Bandwidth connectivity is extremely low in many parts of the world, often delaying or even preventing people from accessing information. Although connectivity has increased by a factor of 10 or 15 over the last decade, average webpage size and number of objects has simultaneously increased by a factor of 60. This has resulted in what Subramanian terms an "unusable web"; the addition of video, audio and images has created huge web pages that take minutes or even hours to load in low connectivity worlds.
In his talk, Subramanian describes a range of techniques that he and his colleagues are developing to enhance information access in three scenarios of poor connectivity. These techniques illustrate the type of technologies being devised by a new group in Computer Science termed "Computing for Development." The focus of this group is on the design, implementation and evaluation of new computing innovations that enable global social and economic development. Since first world technology can often be a bad fit, this group instead seeks technologies that are locally appropriate, cost-effective, and easy to use.
The first low-connectivity scenario Subramanian discusses is that facing rural mobile users, who rely on low-end mobile devices and can thus only access voice and SMS services. To address the massive need for SMS services for this scenario, Subramanian and his colleagues have developed an SMS-based protocol stack for mobile applications that makes it possible to compress large quantities of information. The so-called UjU stack enables the compression of information into a 140-byte stack, while an affiliated UjU Create App interface enables anyone to create their own apps and forms. These forms are essentially turned into structured records (tables) that can be filled out and transmitted through a short message on a mobile phone. To date, UjU has already been used for microfinance applications in Mexico, mobile health data collection in India, and other applications in Ghana. Subramanian and his colleagues are also rolling out a live SMS search engine in Kenya and a data-over-GSM voice stack to support data connectivity over cellular voice.
Shared low bandwidth networks present a second low-connectivity scenario. In this scenario, an example of which might be a school where 2 Mbps of connectivity is used by 400 students, Subramanian suggests that a completely new Web architecture is needed. He and his colleagues have deployed an early version of such a system called Rural Café User Interface. Typically, a web browser sends dozens of requests when it is loading a particular page, since each site draws content from various sources and advertisers. Rather than being able to attempt to load as many windows and pages as possible, which results in even slower access, every user in Rural Café has a queue of what their search requests are. Users can search for anything at any point, but the interface acts as a planning tool by reporting how long (in seconds or minutes) the user would have to wait to load any particular site. The queue is persistent, so it doesn't change depending on how many new windows users try to open. This system is already being deployed in a few schools and universities in Kenya and India.
The third scenario is that of schools that have computer access, but no connectivity. To address this problem, Subramanian proposes the use of "vertical search engines" or contextual information portals that deliver a vertical slice of the Web in a hard-disk and provide an offline searchable and browse-able Internet. The portals are locally searchable and composed of many web-based services. Since the portals allow the user to search the local cache for the information they need rather than the URLs themselves, many local requests can be handled without browsing, supposing the local cache is strong and based on local interests and content. This is a good tool for either improving download times for people who have limited connectivity, or for enabling access for information for people without any connectivity at all. So far, the system has been piloted as an information tool for students and teachers in five schools with computers but no connectivity around Nairobi, Kenya.
