Editing 1473: Location Sharing
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==Explanation== | ==Explanation== | ||
− | + | {{incomplete|First draft.}} | |
− | Megan is | + | In this comic, [[Megan]] is visiting a website on her mobile phone. After loading it, the website {{w|Location-based service|asks for her location}}, which Megan permits the phone to give. The choice between allowing or denying a website or app access to certain information is common among smartphones. The term "location sharing" specifically refers to when a smartphone user shares her location with such an entity. An example of which is a weather app which would need your location in order to find the correct forecast. |
− | Heisenberg | + | Megan is then asked her {{w|momentum}}, which she denies. The joke is based off of the Heisenberg {{w|uncertainty principle}}, which, in quantum mechanics, states that one cannot accurately know both the location and momentum of any particle simultaneously. This principle was previously referenced directly in XKCD comic [[824]], and as a topic for discussion in XKCD comics [[1404]] and [[1416]]. In the context of the comic, Megan acknowledges the website's attempt to violate the uncertainty principle by saying "nice try". |
− | + | It might also refer to security problems that appear if an untrusted application is given access to the gyroscope data. Access to gyroscope data can be used for reading passwords entered into the phonescreen or even guessing keyboard strokes on a keyboard lying on the same table as the phone. | |
− | The uncertainty principle | + | The title text refers to the inclusion of {{w|gyroscope}}s in modern cell phones that measure angular momentum, mostly to detect when the phone is tilted, but also used in a few mobile games. Randall suggests the poor accuracy of the compasses in mobile phones (measuring the angular position) is due to the gyroscopes being too good. (If both the gyroscope and the compasses were completely accurate, it would violate the uncertainty principle). Modern phones also include varied technologies (such as GPS) to pinpoint the user's location, with varying degrees of accuracy. |
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+ | There is no way to directly measure absolute momentum in a mobile phone (well, anywhere else either). This is done normally by differentiating the position in time (from GPS signal) or by integrating the accelerometer signal. In the first case you obtain the average speed, the second technique is subject to numerical error adding up in time. | ||
==Transcript== | ==Transcript== | ||
− | : | + | First Slide: |
− | + | This website wants to know your location | |
− | + | Two buttons: "Allow" on left and "Deny" on right | |
− | + | Allow is highlighted | |
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− | : | + | Second Slide: |
+ | No text | ||
− | : | + | Third Slide: |
− | + | This website wants to know your momentum | |
− | + | Two buttons: "Allow" on left and "Deny" on right | |
− | + | Deny is highlighted | |
− | |||
− | + | "Nice Try" | |
{{comic discussion}} | {{comic discussion}} | ||
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