## 2 Internet of Things  
IoT is a multidisciplinary field that covers many subjects from technical issues (such as routing protocols) to a combination of social and technical problems (e.g., security). IoT represents a vision in which the Internet extends into the real world encompassing every uniquely identifiable object. Figure 1: Internet of Things (IoT) with its connections and related entities. This vision is ubiquitous computing. Initially, [PERSON] [11] in 1991 coined the term \"Ubiquitous Computing\" that can be truly realized by IoT. [PERSON] [12] proposed the term \"IoT\" in his presentation at Procter & Gamble (P&G) in 1999. Also, [PERSON] [13] used the same notion in his book in 1999. The IoT first became popular through [PERSON] et al. [14] (from MIT Auto-ID center) in 2000. LG announced its first Internet refrigerator plans in 2000. During 2002-2004, IoT was mentioned in mainstream publications such as Forbes [15], the Guardian [16], Scientific American [17] and the Boston Globe [18]. International Telecom Union (ITU) published an annual report of the IoT [19], which extended the concept of the IoT in 2005. In that report, there are four key enablers to the IoT:  
1. Feeling Things (such as sensors and wireless sensor networks)
2. Tagging Things (using Radio Frequency Identification (RFID))
3. Thinking Things (such as smart materials, smart clothing and wearable computing, smart homes and vehicles, and robotics)
4. Shrinking Things (using nanotechnology to make products smaller and smaller)  
In 2005, [PERSON] and [PERSON] [20] published their book in IoT topic. European politicians initially used IoT in the context of RFID technology, e.g., in the titles of some RFID conferences such as \"From RFID to the IoT, Pervasive networked systems\" (2006) and \"RFID: Towards the IoT\" (2007). In March 2008, the first scientific conference [21] was held in IoT. In 2008, a group of high-tech companies launched the Internet Protocol for Smart Objects (IPSO) Alliance for the following goals [22]:  
1. Interoperability: Organize interoperability tests that will allow members and interested parties to show that products and services using IP for Smart Objects can work together and meet industry standards for communication. 2. Invest in Innovation: Help innovators in small companies who are making IP devices and web objects to gain visibility in the industry. 3. Promote IP: Promote the use of IP as the premier solution for access and communication for Smart Objects - in print, in public, and in the media. 4. Uphold Standards: Support Internet Engineering Task Force (IETF) and other standards development organizations in the development of standards for Smart Objects. In April 2008, U.S. National Intelligence Council listed the Internet of Things as one of the 6 \"Disruptive Civil Technologies\" (Biogeotechnology, Energy Storage Materials, Biofuels and Bio-Based Chemicals, Clean Coal Technologies, Service Robotics, and The Internet of Things) with potential impacts on US interests out to 2025 [23]. In Jan 2009, President [PERSON] promoted the idea of a smarter planet as a developing national strategy and consequently gave worldwide concern. A dedicated European Union committee published an action plan for Europe which sought to create a new and broad paradigm: the transition from a network of interconnected computers and people, to a network of interconnected people with things or things with each other (IoT) in 2009 [24]. [PERSON] at Frost and Sullivan [25] anticipated that year 2014 would be the year of the Internet of things and the focus of both IT buyers and sellers shifts to IoT. Also, more data would be generated by machines ('things') than by human beings in 2014. Today, the IoT is used to denote advanced connectivity of devices and services that go beyond the traditional machine to machine and covers a variety of protocols and applications. Connectivity will take on an entirely new dimension, and future global networks will consist of not only humans and devices, but also all sorts of things.