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Question

Motion sensors also can help map someone’s travels, such as on a subway or bus ride. A trip produces motion data that are different from the more brief, jerkier movements of something like a phone being pulled from a pocket.

For a 2017 study, researchers designed an app to extract the data signatures of various subway routes. They used accelerometer readings from Samsung smartphones of people riding the subway in Nanjing, China.

A tracking app picked out which segments of the subway system a user was riding. It did this with an accuracy of 59 to 88 percent. How well it performed depended on how many subway stations the people rode through. (The app improved as the rides lengthened from three stations to seven stations long.) Someone who can trace a user’s subway movements might figure out where the traveler lives and works. They might tell where the user shops or map out someone’s entire daily schedule. It might even — if the app is tracking multiple people — figure out who the user meets at various places.

Accelerometer data also can plot driving routes. And other sensors can be used to track people in more confined spaces.

One team, for instance, synced a smartphone mic and portable speaker. That let them create an on-the-fly sonar system to map movements throughout a house. The team reported the work in a September 2017 study.How do motion sensors determine information about a person?

They store information regarding a person's health.

They record a person's surroundings.

They record who a person interacts with.

They track where they go and how they move.

Answer 1

Motion sensors primarily track where a person goes and how they move. They collect data on movements, which can be analyzed to determine travel patterns, such as those seen in subway or bus rides. By analyzing the accelerometer data, researchers can identify specific routes and segments of transportation that an individual takes. This data can reveal information about a person's daily schedule, locations they frequent, and potentially even their interactions with others, depending on the scope of the tracking.