Cooltown: Communications for Nomadic Users. Introduction Ever thought telecommunications was cool? Well Hewlett Packard certainly think so. In the Mid 1990s they launched a project called Cooltown, which offers a web model for supporting nomadic users based on the convergence of web technology, wireless networks and portable devices. Cooltown is a vision of a technological future where people, places and things are all represented on the Web, or as Hewlett Packard describe it, "a place where e-services meet the physical world, where humans are mobile, devices and services are federated and context aware, and everything has a web presence". The goal is to attach information to objects, so that computer projectors and printers, art works and books, and even physical locations such as conference rooms and city buses can be identified on the Web. The virtual world will meet the physical world and user assistance will be context sensitive in both.
Cooltown in Action In www.cooltown.com the smart device in your pocket (PDA, cell-phone, watch) becomes your remote control for eservices. On command it can access and capture information wirelessly transmitted by devices called beacons. These beacons broadcast a URL for the object or place, pointing you to a web presence providing product information, entertainment, advertising, or other e-service gateways. Once gathered and bookmarked, URLs can be sent to remote web locations, or beamed directly to a variety of web appliances using a beaming technology called e-squirt. Using this technology your handheld wireless device can 'squirt' the URL, enabling you to instantly put presentations on a screen, documents on a printer, or music on a connected stereo. Here are three real examples built for the Cooltown project. Art Gallery/Museum The Cooltown Museum and Bookstore offers visitors a Web-enhanced experience. As visitors tour the museum, their portable digital assistant (PDA) can receive Web URLs from wireless beacons. These beacons are small infrared transceivers located close to pictures or sculptures; the URLs link into a Web of information about the items. Using the PDA's Web browser, visitors can read or hear about the artist or the work and about related art works in the museum. The URLs can also be stored as bookmarks for further study or they can be used to select reproductions of the artwork from the museum's online store. The museum staff uses the same URLs for inventory control as the URLs point to the object's point of Web presence. As visitors move into the Cooltown Museum bookstore they can use their PDAs to sense the URLs associated with books, calendars, and posters for sale. These URLs will give them book reviews, available inventory of calendars, and other choices of posters for example. The museum bookstore’s Web portal provides services to assist in buying books, including a service to order books that are not available. In addition, the bookstore offers a printing service, for visitors to print out Web pages that they collected during their visit, or even order reproductions of paintings to be printed just in time for purchase at the exit. Conference Room As you enter a Cooltown conference room you can collect the URL for the room from a beacon or tag into your PDA or cell phone. The URL will lead to a Web page for the room giving links to, for example, the room's projector, printer, and electronic whiteboard, as well as links to Web-based maps. The Web page is served from a "PlaceManager", a Web portal service dedicated to the conference room. This portal is a physically-based local equivalent to World-Wide Web portals like Yahoo and Excite. This meta-service acts as a container for the services of the room and as a portal or gateway to Web access for visitors. Its contents can be tailored to the conference room's attendees or the current activities.
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Workers in the room can also "e-squirt" URLs at the room’s "Web appliances" such as Web-enabled projectors or printers. E-squirt is just a wireless transfer of a URL over a short-range wireless link, like IR or Bluetooth. Squirting a URL at the projector will project the corresponding Web page, creating a shared Web browser. Squirting a URL at the printer will fetch the Web pages and print them. In this way a worker armed with only a cell phone or even a wristwatch can use the conference room facilities by squirting URLs referencing content available on the Web. To support visiting guests of an organization the PlaceManager acts as a proxy and firewall. This allows visitors access to room facilities without compromising the surrounding facility. Visitors inside the conference room and therefore inside the host’s firewall, also need to traverse that firewall to access world wide Web content and content within their company's Intranet. For this users may employ a secure "Web Tunnel" that encrypts traffic and authenticates users over HTTP links. WebBus This is mobility in its simplest form: the entire infrastructure is bolted to a bus. In practice that means the bus is fitted with a small computer equipped with both short-range (intra-bus) and wide-area (Internet) wireless connectivity that runs the PlaceManager for the bus. Riders on the bus interact with on-board Web services exactly like they would interact with the conference room: they pick up beaconed URLs pointing to the bus service, then use its services via a Web browser. The bus services can be "location-aware": they can depend upon the position of the bus. The Web -bus computer contains a Global Position Sensor (GPS) and its output is readable by HTTP "GET" requests. Services running on the bus computer can use the coordinates of the bus to tailor information for bus riders. For example, mapping services can show the bus' current location, shopping services can show near by stores, and tour services can highlight sites riders can actually see. The same technology can be applied to bus-system users outside the bus using the wide-area wireless Internet connectivity of the bus computer acting as a Web server. A potential rider equipped with a PDA and waiting at a bus stop can pick up the URL of the bus from the bus stop and inquire about the bus' location. This service is actually a composite of the Web-bus locator service and existing Web mapping services. The Web-bus may offer a "notification" service where it offers to alert riders a few minutes ahead of a bus arrival by, for example, calling them on their cell phone. And the bus company can use the Web-bus service to automate its analysis of the overall bus system.
Infrastructure The Cooltown project is about exploring the infrastructure to support nomadic systems. Web servers are put into printers and information like artwork is put into web servers. Physically related things are grouped into places embodied in the web servers. Finally, URL beaconing and automatic sensing are used for addressing which, together with localised web servers for directories, makes it possible to create location-aware ubiquitous systems. The Cooltown infrastructure is comprised of three layers; Sensing, Context & Physical Discovery, and Content Exchange, as shown in the diagram below.
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Sensing Sensing is the means by which users acquire URLs from their surroundings or from physical entities using technologies like infrared or short-range radio frequency, barcodes, electronic tags, and optical recognition. Sensing can be direct, the beacon or tag directly presents the URL of the web resource, or indirect via the presentation of an ISBN barcode which has to be resolved to a specific URL. The figure below shows a PDA with 3 sensing mechanisms (IR, barcode and RF). URLs and identifiers that are read by one or other of the sensing devices are multiplexed and announced as sensing events bearing the URL. Applications consume the events and handle and/or store them for later retrieval.
Context & Physical Discovery Connections between the entity or place and a web page are created by attaching beacons or tags to points on physical entities or in physical places and by storing appropriate URL values in them. When a user approaches a beacon or tag, they can use their device to find the corresponding web page. The user has "discovered" an electronic representation. Representation of places will be of particular interest to nomadic users. Web pages for places can help users orient themselves, providing maps or directions to nearby physical locations. But representation of places also provides context: virtual collections of related resources. Places are distinguished from other types of context by the fact that they are based on an underlying physical domain. The idea is for the place context to be made accessible when the user enters or nears the corresponding physical domain. Implementation of place context is through a web server with appropriate content describing the place. The points of web presence of the designated objects will appear as links in the place's web pages. A place manager provides access to and configuration of the data associated with one or more places. The place manager has the following functions: • • •
It maintains directories of the resources in each place, and provides an interface by which resources may be added, queried and removed. It acts as a resolver for each place, for looking up resources from their identifier. It acts as a web server, providing information about each place's resources in the form of HTML (for user browsing) and XML (for programmatic access).
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Content Exchange Content exchange supports the opposite of browsing: the nomadic user can push content into the infrastructure, rather than just pulling content from it. Direct content post Pushing (or 'posting') content works between a source of content and a sink for content. For example, a nomadic user entering a conference room with a camera, photographing the content on a white board, then printing the image on the room's printer. The camera is the source for the image content; the printer is its sink. To accomplish direct content transfer a simple push interaction is required: the content source opens a connection to the sink and writes the content. The only agreement needed between sources and sinks is the format of the data. The approach is to use an ASCII encoded XML format carried in a MIME entity. Should the source attempt to transfer a type of content that the sink cannot handle, such as sending audio to a printer, the response indicates this error. Indirect content post In addition to direct content like the image from a camera, it is possible to post content containing hypertext links to other content. One example is an IR beacon transmitting a simple kind of "document" containing a single URL. The beacon acts as a broadcast source of this URL; a PDA that picks up the beacon acts as a sink for the content. Transferring a URL instead of direct content has the advantage that the sink may be able to render the content with higher quality than the device that possesses the URL. For example, if a PDA transfers a link to a printer, then the printing service can download and print the document at a high resolution. This can be a distinct advantage over downloading the content to the PDA, rendering it on a tiny screen, and then printing the result.
(A) Direct content post. (B) Indirect content post where the posted content links web content on a third-party origin server. (C) Direct content post with concurrent post of device settings; the settings would typically be modifications of previous settings obtained by a GET from the device.
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Technology A number of technologies are utilised in the Cooltown, some are now reaching the consumer market, such as GPS, Bluetooth and Web Tunnels, while others are specific research products of the Cooltown project, such as the Web Presence Manager and E-squirt. A brief description of the key technologies used in Cooltown is provided in the following box. Coolbase appliance server The CoolBase Appliance Server and coolkit implement an object-oriented web application server designed specifically for embedded systems. In addition to the small native C implementation that is CoolBase Appliance Server, coolkit is a GUI-based tool for easily composing embedded Cooltown web services.
E-squirt E-squirt provides an API and implementations for a new device interaction model, by-reference invocation with reflected user interface. E-squirt is available for the following operating systems: PalmOS, WinCE, Linux, Symbian EPOC and Win32.
Web presence manager The Web Presence Manager implements a directory of relationships, a dynamic parser, and a template-based engine to present views of an entity (e.g., a place) and its contextual relationships (e.g., the people, things and services in or related to the place).
Beacons Beacons are small hardware devices whose function is to broadcast references (e.g., URLs). E-squirt software implements the receiving function for beacons.
Secure web tunnel Secure Web Tunnel (SWT) is a service which supports transparent secure access to web resources that exist behind a firewall.
GPS Short for Global Positioning System, a worldwide MEO satellite navigational system formed by 24 satellites orbiting the earth and their corresponding receivers on the earth. The satellites orbit the earth at approximately 12,000 miles above the surface and make two complete orbits every 24 hours. The GPS satellites continuously transmit digital radio signals that contain data on the satellites location and the exact time to the earth-bound receivers. The satellites are equipped with atomic clocks that are precise to within a billionth of a second. Based on this information the receivers know how long it takes for the signal to reach the receiver on earth. As each signal travels at the speed of light, the longer it takes the receiver to get the signal, the farther away the satellite is. By knowing how far away a satellite is, the receiver knows that it is located somewhere on the surface of an imaginary sphere cantered at the satellite. By using three satellites, GPS can calculate the longitude and latitude of the receiver based on where the three spheres intersect. By using four satellites, GPS can also determine altitude. GPS has applications beyond navigation and location determination. GPS can be used for cartography, forestry, mineral exploration, wildlife habitation management, monitoring the movement of people and things and bringing precise timing to the world.
Bluetooth Bluetooth wireless technology enables links between mobile computers, mobile phones, portable handheld devices, and connectivity to the Internet. The Bluetooth wireless specification includes both link layer and application layer definitions for product developers, which supports data, voice and content-centric applications. Radios that comply with the Bluetooth wireless specification operate in the unlicensed, 2.4 GHz radio spectrum ensuring communication compatibility worldwide. These radios use a spread spectrum, frequency hopping, full-duplex signal at up to 1600 hops/sec. The signal hops among 79 frequencies at 1 MHz intervals to give a high degree of interference immunity. Up to seven simultaneous connections can established and maintained.
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Conclusions The hope is a world in which "technology transforms human experience from consumer lifestyles to business processes by enabling mobility. Cooltown is infused with the energy of the online world, where web based appliances and e-services give you what you need, when and where you need it, for work, for play, for life." …Hewlett Packard It all sounds pretty cool and in a recent article in Intercom magazine Neil Perlin talked about the potential effects on technical documentation this technology could have, such as "new work in unusual places", in which he quoted the example of creating web pages for each beaconised holding in a museum. I do have one concern about all this though. How easy will it be to make my web presence unknown to the rest of Cooltown? The paradox of the online, wireless world of ubiquitous systems, is that while is has seemingly made for a more democratic, less hierarchical society, in which people can communicate anytime, any place, anywhere, it could easily have the opposite consequence, in which you can be located, monitored and recorded at anytime, any place, anywhere….and by anyone, but maybe that is just the paranoid anarchist in me!! "I will not be pushed, filed, stamped, indexed, briefed, debriefed, or numbered! My life is my own."---No 6 (from the Prisoner 1967). I always thought that quote was pretty cool to.
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