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The “Internet of things” is a term coined by Massachutes Institute of technology (MIT).The term describes a vision of the internet in the future where all “things” or objects are on one network. These “things” will contain:
- A Unique identifier
- Its own “individual digital presence”- it will know who and where it is.
- The ability to process or exchange information
- Can store data about itself
- Is capable of participating in or making decisions relevant to its own destiny on a continuous basis?
The term Internet of things covers the whole infrastructure such as the hardware, software and services supporting the networking of physical objects. (European Commission, 2008)
A Brief History of the Internet
The first development to the present World Wide Web was Enquire. This contained a project management tool that “allowed pages of notes to be linked together and edited.” (Anderson, 2007). Eventually, after the evolution of various technological and software developments was the World Wide Web created. With a browser/client that could view and edit pages of marked-up information (HTML). The edit function only really materialised in later browsers: Viola WWW and Mosaic (the current Netscape browser.).
Introduced in 1994, web 1.0 consisted of an individual source (e.g. Website or a file) publishing information which could be viewed or downloaded by a client. This was a straight client-server network, so those individual clients were not able to fully interact with the source. The main purpose of web 1.0 was “to push information to a relatively passive audience.” (Castelluccio, Michael, 2008). This “passive audience” would consist of users who would create their own websites. So, the majority of web 1.0 websites contained HTML tags scattered all across the web but without the ability for users to add to the website unless they understood HTML. This left internet interaction exclusive to people who were HTML literate.
In 2008 web 2.0 became the associated term for the uprising of new products and services on the internet. The term was created four years previous by Dale Dougherty, vice president of O’Reilly Media Inc.2 Evolving from web 1.0, 2.0 represented a more peer to peer environment. This concept emphasized more the individual user having the ability to upload content (pictures, music, and videos) to a website. These websites took the form of blogs, wiki’s, podcasts, RSS feeds and social networking sites. This user interaction coupled with improvements in networking technology, has made the internet more personal and accessible. According to (Anupriya Ankolekar et al, 2007), Web 2.0 is distinguished mainly from Web 1.0 by the following characteristics:
- Community: Web 2.0 offers multiple users to work together and to share information. So the website is more effective than that of just having one contributor to the site. “Each contributor gains more from the system than she puts into it.” Such community website examples would be the music file sharing service Napster and an event calendar Upcoming.
- Mashups: Services from different sites can be brought together, in the creation of a new website such as using Google maps in your website.
Web 3.0- The Semantic web
Web 3.0 or a semantic web is being proposed as the natural progression for the development of the Web. A definition from Paul Anderson in an article in the American scientific explains that the semantic web is about the shift from documents to data- the transformation of a space consisting largely of human-readable, text oriented documents, to an information space in which machine readable data, imbued with some sense of meaning “is being exchanged and acted upon”. This “machine readable data” would consist of metadata. Defined by (NISO 2004) “Metadata is structured information that describes, explains, locates, or otherwise makes it easier to retrieve, use, or manage an information resource. Metadata is often called data about data or information about information.”
There are current technologies which are being developed by the W3C (World Wide Web Consortium) which aims to bring development towards a Semantic Web. These technologies such as RDF (Resource Description Frame work) can be used to give “meaning” to the metadata on the World Wide Web. RDF according to (Berners-lee et al, 2001), encodes a “triple” (object, subject, verb) using XML tags. These tags are “hidden labels that annotate web pages” but these tags have no meaning to the document. With RDF, the document makes decisions that things (people, webpage’s) have properties (is an author of) with certain values (another webpage). He goes on to develop that these objects can be identified by an URI (Universal Resource Identifier), the best known being a URL (Universal Resource Locator). The triples produced by RDF “form webs of info about related things.” And with URI encoding the document, the URI makes sure that this information is not just words but is tied to a unique definition that everyone can find on the web?
But how can a machine differentiate between these terms/objects? OWL or Web Ontology Language is a formal language which represents ontologies (intelligent agents) in the semantic web. These “intelligient agents” will help relate various types of metadata from the RDF. According to (Berners-lee et al, 2001) ontologies have taxonomy and a set of interference rules.
- Defines classes of objects and relations among them.
- And can express a large number of relations among objects by assigning properties to classes and allowing subclasses to inherit such properties.
Interference Rules help distinguish similar terms, for example that an address from Sligo it, being in Sligo, must be in Co. Sligo, which is in Ireland. (Berners-lee et al, 2001) explains the computer doesn’t truly “understand” any of this information, but it can now manipulate the terms much more effectively in ways that are useful and meaningful to the human user ?. With the ability to perform this function more accurate web searches can be produced, as the searches are based on a precise concept instead of using vague keywords.
Turn to the Internet of Things
The possibilities of the semantic web can give a base for the IOT to be developed, due to the quick, intelligent and personal nature of semantic technologies and to the fact that URI’s can point to anything. This includes physical objects, which through RDF can promote their functionality (What they do and how they are controlled) (Berners-lee et al, 2001). (Artem Katasonov et al, 2008) suggests that for the IOT to happen the semantic base or (middleware) must be decentralised. This is suggested due to the high volume of devices connected to the internet, administrators will have it difficult in managing such a wide variety of unscalable information and media. There will be a need for “self-manageable complex systems”. They also go on to argue that semantic technologies firstly, will function as the basis of heterogeneous components and the integration of data across many domains and secondly, will be used for the coordination of the intelligent agents “representing” those resources.
As previously mentioned in the last section, “intelligient agents” can roam as a “middleware” between the heterogeneous component and an “autonomous software agent”. (Artem Katasonov et al, 2008) defines the role of the agent as having the ability to monitor the state of the component, make decisions on behalf of the component and to discover, request and utilize external help if needed. The agents offer a more flexible system, one in which networks will be monitored easily as information will be already processed.
What are Things?
The IOT will be based on these intelligent objects which will all communicate with the each other and the end user. These things as previously stated will be individual entities which can interpret and communicate with the internet. They will have an active part within the internet and have the ability to share information about themselves and their environment. (European Commission, 2008) gives a few examples of objects which do menial tasks but use very smart systems and advanced network connections:
Mobile Phones will have the ability to be used as credit cards, travel passes and to gain information from the internet. With the use of NFC (Near Field Communications) technology could this be possible. They estimate that there will be 1billion by 2015.
Another example given is a fully automated warehouse, where items are checked in and out. Orders can be passed directly to suppliers automatically. All the cause of RFID (Radio Frequency Identifiers) attached to goods and products. Manufacture’s can view the market needs in real time, this saves time and energy leading to the whole process being more environmentally friendly.
RFID and sensor technologies will help in early diagnostics of patients help doctors make more informed decisions and it will produce alerts if a patient’s health deteriorates. All information will be gathered through lightweight, intelligent sensors on the patient or by possible smart dust (microscopic computers) within the patient.
Through a network of sensors can temperature and lighting be dynamically controlled. This helps intelligent houses to reduce energy consumption without the loss of an individual’s comfort.
The IOT will have an effect on how certain conditions (traffic, weather, air particles, water pollution, and the environment are monitored and examined.
Radio frequency Identification tags typically are small devices that can be embedded in or attached to objects for the purpose of identifying the object over a radio channel (Karjoth et al, 2005). RFID consists of a reader and a tag.
Uses of RFID technology
RFID has been in use now for many years. It started being used in World War II, by British planes to help them discover their own aircrafts using the Identification Friend or Foe (IFF) system. In the 1960’s it was used by Los Alamos National Laboratory to gain access control to there company. People in the company wore RFID badges so they could be identified. This helped limit access to important areas in the company and also made it harder for badges to be forged. Since then RFID has being used to identify animals, track airline luggage, locate lost items, prevent theft and make toys more interactive. Recently, a few multi-national companies have shown an interest in this technology such as Wal-mart, Tesco, and the US Military. The main aims according to Roy Want is to make the cost of tags decrease, streamlining the tracking of stock, sales and orders (Want, 2006). With the ability to store information and to connect with tags over a digital communication network, RFID can track the journey an object makes between the factories, warehouses, vehicles, and stores (Want, 2006).
The tag, when attached to an object can be identified by the reader over a radio channel. Tags can be read easier and faster than that of normal barcodes, usually within the range of a few meters. An RFID tag contains two main components: An antenna which is a flat, metallic conductive coil which has the potential to be less than half a millimetre in size, is used to send and receive radio waves. An antenna can be printed, etched or stamped on a plastic foil or silicon chip which (Karjoth et al, 2005) defines as a substrate. The second component the silicon chip is a microchip or Integrated Circuit (IC). According to (Plaggenborg, 2006), the smallest IC is 0.15 mm x 0.15 mm and is 7.5 m thick.
Both the antenna and IC are attached to a plastic tag. The main types of RFID tags are active, passive and semi-passive.
- Active tags contain their own internal power source. The word active is due to the fact that it uses an active radio frequency transmitter to communicate in a session with the reader. This gives active tags a better read range than passive tags, covering hundreads of meters. It can communicate through difficult environments such as water or heavy metal, which Plaggenborg states is impossible for passive tags. He goes on to say that active tags have a greater amount of memory and are more secure because of their more advanced IC processing capabilities.
- Passive tags use electromagnetic waves from the reader to attract a connection to the tags antenna. Power is transferred from the reader to the tag through the electromagnetic waves. Because it does not need its own battery passive tags can have an unlimited lifespan (in theory). But a passive tags response is limited by the readers signal strength. The tags response or backscatter is limited by its range which is around four to five metres. Because of there simple design and low cost (five cent a tag), passive tags are mainly used in the retail industry.
- Semi-passive tags contain both a small battery and require waves from the reader to send a response. The small battery within the tag is used for the IC’s logic and to give a response to the reader through the antenna. Due to the small battery these tags have a short lifespan, they are more delicate and are very expensive.
Classes of Tags
Tags are separated into different classes depending on there functionality. This framework which was developed by the Auto ID centre and later by EPC (Electronic product Code), 1separates tags into five different classes. From class one to the greater functionality of class five.
A tag’s chip is either read-only memory (ROM) or read-write. Data which is embedded onto the chip at its manufacturing stage that can only be read was called class 0 tags. Tags can be used with static random access memory (SRAM) to produce what is called a Write Once Read Many (WORM) tag. The unique id in this tag type is permanently stored on the chip.12 Read-only chips are mainly used for tracking. Read-write allows the ability to change the chips ID and also to add some data to the tag’s memory. Information can be programmed onto read-write chips but these are very expensive. EEPROM (a technique for erasing memory and overwriting it) can also be used for this process. Also chip’s can be manufactured in such a way that the ID is cannot be altered but that information can still be written to memory. Passive tags can store from 32 bits to 128 kilobytes of data. Since active tags have their own battery they can afford to store more, some tags having the ability to store up to one megabyte of memory.13
(Plaggenborg, 2006) states that there are four frequency bands, each with their own characteristic in regards to communication. For example low frequencies can penetrate such conditions as water and metal but are much slower than that of high frequencies. High frequencies are faster but with the defect that they cannot penetrate the conditions mentioned. RFID operates on an unlicensed spectrum space called ISM (industrial, scientific and medical). The ISM frequencies vary on which country you are in.
There are two distinct systems in regards to its physical properties to which RFID communicates from the tag to the reader. Low frequencies and high frequencies use near field communication through the process of inductive coupling from a magnetic field. The reader creates a magnetic field between itself and the reader. The reader induces an electric current in the tags antenna. From this, the reader gains the tags ID and also gives power to the tags IC. The reader learns the tags ID, by varying the load on the antenna’s coil which changes the current on the reader’s communication coil.12 Ultra High frequency and Microwave frequency use far-field communication. It uses the physical property of backscattering, which is the process of the reader sending a continuous signal frequency that is reflected back by the tags antenna. The tag encodes the reflected signal with information using modulation (i.e. changing the amplitude of the waves returned).12 RFID uses a frequency spectrum similar to that of wireless and Bluetooth networks and hybrid tags are currently being developed for them to communicate.12
As with any established product and technology, RFID has many proposed standards. Standards provide many benefits such as universal procedures for all and interoperability between technologies. There are a number of bodies in the development of RFID Technology
- EPC global
- FCC 12
(Plaggenborg, 2006) states the point that the main areas to which standards have being proposed are
- Air interface protocols – These are ISO standards ranging from ISO 18000-1 to 7 and are concerned with how tags and readers communicate. EPC has its own set of standards similar to ISO’s 18000-6 (860-960 MHZ range). These EPC tags are not interoperable with each other and are not interoperable with the ISO standard. So EPC are working on a new set of protocols (GEN 2) that can work with the class 0 and class 1 passive tags and should be closely aligned with the ISO standard.12
- Data content and Encoding – This is concerned with “data formatting or organisation, numbering schemes” (Plaggenborg, 2006).
- Conformance- This is the testing of products to see if they meet the standards.
- Applications- How standards are used on certain labels13
Electronic Product Code
Is a unque code which is contained within an RFID tags memory. It is much the same as the barcode scheme UPC for identifying physical objects. EPC is differs from UPC as it has the capability to identify every single product item individually. For example when a shopkeeper scans a barcode the code relates to the type of product he is scanning (this packet is a packet of Jacob biscuits).If he scanned another packet of Jacob biscuits he would get the same result. In contrast, if he scanned an EPC tag he would be able to identify not just the make of the product but the individual product he is scanning. So this time when he scans another packet of Jacob biscuits, (that is not the original packet) it will come up with a different result.
EPC uses a 96 bit number to identify a product. This gives it a huge scope of numbers for product identification as opposed to UPC.
As shown in figure 3 The EPC code consists of many components. The header identifies what coding scheme is in use. There are many different schemes to which Matt Ward gives three examples Global Trade Identification Number GLTN, Serial Shipping Container Code SSCC and Global Location Number GLN.15 The Manger number defines the company that produced the product (Manufacturer). The object class identifies the actual product. The Serial number refers to the individual item/product. EPC’s 96 bit code according to Matt Ward can identify “268 million companies”, “each manufacturer can have 16 million” “object classes” and “68 billion serial numbers “for every individual object.
Matt Ward in his paper (Ward et al, 2006), also discuss about the EPC Network Architecture. He explains, clearly how RFID tags do not work in isolation but are part of an overall system be it a supply chain or any kind of logistical recording. He notes how the RFID tag can work as the primary key in representing a product within the database. A vision of this technology is being developed which is called the EPC Network Architecture. The architecture consists of many tags being connected through their readers to an organisations database or back-office enterprise system.
In the previous chapter we observed the possible middleware for the Semantic web. Well here are the key technologies which (Ward et al, 2006) suggests are appropriate for supporting the massive increase of information that will result from in an RFID system.
- Savant is as he puts it is the middleware software system that links reader devices and processes the information streams from tags. It acts as the gateway to the enterprise systems and database applications, providing filtering, aggregation and counting of tag-based data. (Ward et al, 2006)
- ONS Object Naming Service much like the Domain Name Service (DNS) on the World Wide Web helps translate the EPC code into a Uniform Reference Locator. This is where it looks up the location of where the tags associated database is.
- Physical Mark up Language (PML) is an XML-based language which uses a standard vocabulary for describing physical objects, observations made by the RFID readers of these objects and observations made about the readers themselves and there exchanging of data throughout the EPC network (Ward et al, 2006). It uses two main vocabularies: one for communication between Savant and the enterprise applications and a second (Core PML) for communication throughout the EPC network. (Seong Leong,2004)
(Ward et al, 2006) notes indirectly about the IOT when he mentions of the possibilities of IPV6 as an alternative to EPC coding. IPV6 is a communication network standard which delegates the addressing and routing of data packets through a network. It is an improved addressing protocol from that of IPV4 which has the capacity up to 4 billion addresses. IPV6 can give 430 quintillion addresses for every inch of the worlds surface.15 But Ward explains that for a tag to have an IPV6 address, it would no longer be used as an assigned permanent identifier on objects. Saying this he highlights the fact that the U.S. military are investigating and planning to use IPV6 tags in the near future.
Readers can be handheld or a fixed device. Examples of handheld readers are similar to that of barcode readers, but readers can be placed in PDA’s or mobile phones. Class 5 tags are actually designed to be readers; they can read and exchange information with other tags.15 Fixed readers are used for electronic tolls or can be placed within walls or ceilings. Readers communicate with a tag to gain its id number. When the reader is held close to a passive tag, the tags antenna consumes the energy from the reader which in turn powers the IC. The IC responds information back. This depends on the type of tag. There are two main types of readers: ones in which the reader can only read information from the tag. These usually operate with an EPC class 1 tag. The other type is readers which can write information onto the tag. This depends on if the memory on the tag is read/write. According to (Ward et al, 2006), Readers are becoming more sophisticated and are beginning to act as an entry to the internet through supporting TCP/IP technologies and other such protocols as DHCP, UDP/IP and wireless 802.11.
RFID’s Relevance to the Future of the Internet
From the research into this area we have seen that RFID has the components to develop a network of communicating things. Because RFID can both send and receive data about an object within various conditions e.g. underwater, through walls etc. We can communicate with solitary objects and their position, condition and other relevant information for whatever purpose they were placed on an object. Through examining various papers on this topic, most come to the conclusion that RFID as a technology is not attractive enough of a proposition for companies to develop at present. RFID is too expensive to be added too or implemented in a manufacturer’s product. Currently, you can get the cheapest RFID’s at 5 cent each.13
Matt Ward sees RFID tags as a stepping stone to ubiquitous computing. There will not be a fully fledged IOT but one in which will be developed systematically. He proposes that the internet will be extended to a level below computational devices, which consists of simpler devices/items. As the RFID technologies become more accepted in the market place, there will be more of a demand for tags that can achieve greater amounts of tasks. Similar to the pre requites we defined in section two, Matt notes the technological developments needed for their relevance in the internet of things.
Firstly, each of these items must be able to identify itself to other items and to the network in general. This is provided for by the introduction and development of RFID technology. Secondly, these items should include some element of embedded computational power in order to act with some level of intelligence. Thirdly, they will need to have some sense of their physical environment and geographical location. Continuing developments in computational science and electronics, particularly work on miniaturisation, tiny operating systems and wireless communication will make this vision increasingly realistic (Ward et al, 2006)
Near field communication
This is a new development in RFID, one of which use’s near field coupling signalling between devices in the 13.56 MHZ band.11 This standard has the ability to read existing passive tags and aims to develop them to communicate with peer devices at a 20cm locality. It was set up by the Near-field communication forum. “The NFC standard aims to streamline the discovery process by passing wireless Media Access Control addresses and channel-encryption keys between radios through a near-field coupling side channel, which, when limited to 20 cm, lets users enforce their own physical security for encryption key exchange” (Want,2006). He also mentions how through this two way authentication process can a more reliable connection be made then that of Wireless and Bluetooth. Reliable in the sense that it would not form any association’s with devices that aren’t local.
Many commentators believe the next development of RFID will be an enabled sensory function. This will give tags the ability to make measurements about its surrounding environment based on such gauges as pressure, temperature, flow-rate and speed vibrations.15 These devices will be connected to the internet by radio frequencies or through wireless communication systems. Due to the batteries capacity, active tags would seem to be more qualified for development.13 Plaggenborg describes in his developmental paper of RFID about Mitsubishi’s research team who developed location aware objects with light sensitive RFID tags. This consisted of an RFID reader with a projector to give precise feedback of a product’s location. The device is aimed at the products in question. It projects a pattern over the product and each pixel shows a different code. This code with its identity is then communicated back to the handheld device. It then uses an (x, y) coordinate to visually give the user feedback. As we can see, it’s not impossible for this technology if creatively used to be developed further.
The amount of memory a tag can store could be limitless if the tag can store and recover its information from a local database. But the tag could not be able to implicitly recover the information all the time. For tags to work more effective, it will need to utilise its self storing capability. Currently a tag can store from 200 to 8,000 bits.12 believes that tags in the future will have the ability to store more information. Leaving to more distributed information being placed in our surroundings.
Standardisations for the IOT
If the IOT is going to happen then interoperability is a must. There are currently a number of groups who are working on low power wireless communication standards between objects. ZigBee, 6LoWPAN, Z-Wave, and Bluetooth Low Energy are the main standards for this type of communication. But the base of communication for the Physical layers for Zigbee and 6LoWPAN is IEEE’s 802.15.4.
Developed and maintained by the IEEE 802.15 working group, 802.15.4 is a low power wireless personal area network (LoWPAN) standard. Released in 2003, it was the first low power-radio standard.18 It is used as a specification for the physical (PHY) and medium access control (MAC) layers. To gain a complete protocol stack other standards are needed to define the higher layers. According to (Orrevad, 2009), the physical of the protocol uses three different frequency bands: 868-868.8 MHz within Europe which allows one communication channel, 902-928 MHz within North America that allows ten to thirty channels and 2400-2483.5 MHz range for the rest of the world and uses up to sixteen channels. This standard aims to work with multiple low cost nodes of a long lifespan. To achieve an IOT such attributes would have to be viable. But this low cost/ low power solution, limits the capability of both the microcontroller and the LoWPAN’s links. The throughput is suggested to reach the 250Kbps limit. And the frame length is only 128 bytes. It uses short 16-bit link addresses, as well as IEEE EUI-64 addresses, to reduce header overhead and memory requirements. LoWPANs make contact over multiple hops. Microcontrollers which work with this standard usually have about 8 Kbytes of data RAM and 64 Kbytes of program ROM.
The main features of IEEE 802.15.4 highlighted within (Orrevad, 2009)’s informative paper are the fact of its use of carrier sense multiple access with collision avoidance (CSMA/CA) which avoids collisions, sharing a single channel with multiple users by using direct sequence spread spectrum (DSSS), with the ability to sleep it gives appropriate energy efficiency and through its use of guaranteed time slots (GTS) it can guarantee sensors transmission if they are critical in nature.
Frames contain a certain patterns in which other devices can understand. Differerent frames have different uses. There are four types of frames defined in the IEEE 802.15.4 standard :
- Beacon, used by a coordinator to transmit beacons
- A data frame, for different data transfers
- An acknowledgement(ACK) frame, used for a confirmation of successful frame transfer
- A MAC command frame, used for handling all MAC transfers between entities
The beacon, ACK, and MAC frames are mainly used for lower layer signalling.
Headers in the IEEE 802.15.4 standard consist of the physical layer (PHY) and medium access control (MAC) layer headers which contain different features that can be set when sending a packet. Maximum physical layer packet size including overhead is 102 octets.19 He adds, if you add link-layer security you add an extra 21 octets for an AES-CCM-128 encryption. This leaves 81 octets available for the higher levels of the protocol stack.
IPV6 is the newest version of the Internet protocol, which was created in the late 1990’s as a solution to the limited numbe
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