From the Labs: Information Technology

A Better View of the Internet
A new map of the network could help route traffic more efficiently

SOURCE: “A Model of Internet Topology Using K-shell Decomposition”
Shai Carmi et al.
Proceedings of the National Academy of Sciences 104: 11150-11154

RESULTS: Researchers have developed a new approach to analyzing networks and have used it to create a map of the physical links between Internet service providers (ISPs). The map shows that the Internet consists of a dense core of a few well-connected nodes, surrounded by a large number of nodes that can connect to one another without going through the core and an intermediate number of nodes that link to the rest of the network through the core only.

WHY IT MATTERS: More and more video and other large files are being accessed online, but because of network deficiencies, downloads can still take hours. In today’s Internet, data is mostly routed through major hubs. The researchers’ map shows that Internet traffic could be routed around the dense central core to avoid congestion, since even if this core is removed, the majority of ISPs are left connected.

METHODS: The researchers enlisted more than 6,000 online volunteers from about 100 countries, who downloaded a program that traced the routes that data packets took from their computers. The researchers collected up to six million measurements a day over a period of two years, identifying about 20 percent more of the interconnects between ISPs than ever before. To investigate the resulting map, the researchers departed from the usual measure of a node’s importance. Instead of simply counting the number of connections, their measure adjusts for the importance of those connections–whether they lead to major hubs or to less connected nodes, for example.

NEXT STEPS: The researchers intend to apply their analysis to other networks, such as human social circles and biological networks that govern intercellular communication.

SOURCE: “Conversation Detection and Speaker Segmentation in Privacy-Sensitive Situated Speech Data”
Tanzeem Choudhury et al.
Interspeech 2007, August 27-31, Antwerp, Belgium

RESULTS: Researchers have developed software that can determine when a conversation is occurring and who is speaking. The voice data collected cannot be reconstructed into intelligible speech, so the system maintains a certain level of privacy.

WHY IT MATTERS: As gadgets such as cell phones become more prevalent, they are constantly interrupting people at inappropriate times. Engineers are interested in building context­-aware devices that can determine when it’s suitable to notify users that someone is trying to contact them. One approach is to let a gadget with specialized software “listen” to conversations and decide whether it should interrupt.

METHODS: The researchers used a wearable microphone to collect conversation data from a group of 24 people over a span of 4,400 hours. As the audio data was collected, it was immediately processed so that only features such as the presence of speech and its rate, volume, pitch, and tone could be estimated. From such scant data, the verbal content of a conversation can’t be reconstructed. To determine who was speaking at any point in the conversation, the researchers used algorithms that looked for changes in these features and pauses in speech.

NEXT STEPS: The researchers plan to analyze more interactions to see how accurately they can determine whether, say, someone is speaking with a boss or a friend.