https://www.explainxkcd.com/wiki/api.php?action=feedcontributions&user=173.245.62.74&feedformat=atomexplain xkcd - User contributions [en]2024-03-28T10:35:14ZUser contributionsMediaWiki 1.30.0https://www.explainxkcd.com/wiki/index.php?title=1425:_Tasks&diff=868441425: Tasks2015-03-22T07:09:31Z<p>173.245.62.74: /* Explanation */</p>
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<div>{{comic<br />
| number = 1425<br />
| date = September 24, 2014<br />
| title = Tasks<br />
| image = tasks.png<br />
| titletext = In the 60s, Marvin Minsky assigned a couple of undergrads to spend the summer programming a computer to use a camera to identify objects in a scene. He figured they'd have the problem solved by the end of the summer. Half a century later, we're still working on it.<br />
}}<br />
<br />
==Explanation==<br />
[[Cueball]] appears to be asking [[Ponytail]] to write an app that determines if a given picture is (1) taken in a national park, and (2) a picture of a bird. The first question is generally harder for a human to answer, but easy for an app that has access to location information and a {{w|geographic information system}} (GIS). The second one is easy for a human but much harder for a computer. This illustrates {{w|Moravec's paradox}} from the 1980s in a modern context. By the 1950s computers were useful for tasks like {{w|trajectory optimization}}, {{w|automated theorem proving|generating novel mathematical proofs}} and {{w|English_draughts#Computer_players|the game of checkers}}, so such high-level computation and reasoning tasks that were hard for humans turned out to be relatively easy for them. On the other hand it turns out to be hard to "give them the skills of a one-year-old when it comes to perception", as Moravec wrote.<br />
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In order to determine whether the user is in a national park, Ponytail plans to determine the user's location using the mobile device. This location will then be cross checked with a {{w|geographic information system}} (GIS) which will be able to determine whether the coordinates lie within a national park boundary.<br />
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Determining whether an image is of a given kind of natural object is far more difficult. This task falls into the area of {{w|computer vision}}. One of the goals in computer vision is to detect and classify objects within an image. This is a very challenging task for a number of reasons.<br />
<br />
:Firstly, humans use size, edge-assignment, movement, and stereoscopic vision when looking at a scene (not a picture of a thing, but of the thing itself) to discern individual objects and then categorize them as foreground or background.<ref>{{w|Figure-ground_(perception)}}</ref> A photograph, however, is a static, monoscopic image that can only provide size and edge-assignment clues. Humans are only able to discern objects from background in photographs by comparing the photo against all of the things they've seen and everything they've learned about those things over the course of their life and identifying matching patterns.<ref>{{w|Visual_perception}}</ref> Presumably, today's computers do not have nearly the processing power or wealth of data available as the human mind.<br />
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:Secondly, the quality of the photograph will have an impact on a computer's ability to match patterns. For example, the object in the photograph might be partially visible or occluded. In the case of a living bird, additional complications arise from the variations among individual birds of the same species and differences in pose (flying, perching in a tree, etc.). Differentiating between visually similar objects can result in false positives. For example, is it a photo of a bird in flight or a plane (or superman!)? Ponytail's estimate of 5 years may be overly optimistic (see [[678: Researcher Translation]]).<br />
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Today's state-of-the-art algorithms for solving this kind of task mostly use local features (e.g. {{w|Scale-invariant feature transform|SIFT}} or {{w|SURF}} in combination with a {{w|support vector machine}} or {{w|convolutional neural network}}).<br />
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The subtitle refers to "CS", which is a common acronym for "{{w|Computer Science}}", of which {{w|artificial intelligence}} and {{w|computer vision}} are sub-disciplines.<br />
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The title text mentions [http://dspace.mit.edu/bitstream/handle/1721.1/6125/AIM-100.pdf The Summer Vision Project] and {{w|Marvin Minsky}} of MIT. In the summer of 1966, he asked his undergraduate student {{w|Gerald Jay Sussman}} to "spend the summer linking a camera to a computer and getting the computer to describe what it saw" ([http://szeliski.org/Book/]). {{w|Seymour Papert}} drafted the plan, and it seems that Sussman was joined by {{w|Bill Gosper}}, {{w|Richard Greenblatt (programmer)|Richard Greenblatt}}, {{w|Leslie Lamport}}, Adolfo Guzman, Michael Speciner, John White, Benjamin, and Henneman. The project schedule allocated one summer for the completion of this task. The required time was obviously significantly underestimated, since dozens of research groups around the world are still working on this topic today.<br />
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A month after this comic came out, {{w|Flickr}} [http://code.flickr.net/2014/10/20/introducing-flickr-park-or-bird/ released] a [http://parkorbird.flickr.com/ prototype online tool] to do something similar to what comic describes, using its automated-tagging software. However, their system answers the question "Is this photo of a park or of a bird?", a much simpler task than the more open ended "Is this photo of a bird?" which is asked in this comic.<br />
<br />
==Transcript==<br />
:[Ponytail sitting at a computer with Cueball standing behind her.]<br />
:Cueball: When a user takes a photo, the app should check whether they're in a national park...<br />
:Ponytail: Sure, easy GIS lookup. Gimme a few hours.<br />
:Cueball: ...and check whether the photo is of a bird.<br />
:Ponytail: I'll need a research team and five years.<br />
:In CS, it can be hard to explain the difference between the easy and the virtually impossible.<br />
<br />
==References==<br />
<references/><br />
<br />
{{comic discussion}}<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring Ponytail]]</div>173.245.62.74https://www.explainxkcd.com/wiki/index.php?title=Talk:1045:_Constraints&diff=77967Talk:1045: Constraints2014-10-28T12:56:00Z<p>173.245.62.74: </p>
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<div>Sometimes, seventeen<br />
<br />
Syllables are not enough<br />
<br />
To just express a '''[[User:Davidy22|<span title="I want you."><u><font color="purple" size="2px">David</font><font color="green" size="3px">y</font></u><sup><font color="indigo" size="1px">22</font></sup></span>]]'''[[User talk:Davidy22|<tt>[talk]</tt>]] 08:25, 21 January 2013 (UTC)<br />
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But sometimes they are!<br />
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I rewrote your third line as<br />
<br />
"To express a thought." --[[Special:Contributions/108.162.216.45|108.162.216.45]] 21:35, 1 November 2013 (UTC)<br />
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<br />
"Whoa." is also an example, but one word examples are particularly easy! --DrMath 06:17, 7 September 2013 (UTC)<br />
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I can't see the image... what's wrong with it ? --[[User:Koundelitchnico|KoundelitchNico]] ([[User talk:Koundelitchnico|talk]]) 14:26, 25 February 2014 (UTC)<br />
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I just don't find the alphabetization thing to be all that impressive. Everything is written like that. Am I missing something about the very concept? (C comes before O, then jump back to the start, N, back to the start, C, E, P and T.)<br />
(I just don't find: I J U back to start S T back to start D O back to start N T back to start F I N back to start D)<br />
(Epigrams employing: G N back to start I Y back to start O back to start L P back to start M back to start E back to start S back to start M back to start A R back to start G I P back to start E) [[Special:Contributions/108.162.242.5|108.162.242.5]] 02:00, 26 October 2014 (UTC)<br />
: Words wholly taken (not letters individually) do come backward alphabetized. --[[Special:Contributions/173.245.62.74|173.245.62.74]] 12:56, 28 October 2014 (UTC)</div>173.245.62.74https://www.explainxkcd.com/wiki/index.php?title=Talk:1437:_Higgs_Boson&diff=77703Talk:1437: Higgs Boson2014-10-24T03:11:04Z<p>173.245.62.74: </p>
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<div>They can lose the DATA about Higgs Boson. To help prevent such possibility, I would like to mention that the found Higgs Boson energy is between 125 and 126 GeV/c^2 [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 12:18, 22 October 2014 (UTC)<br />
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:It may be nitpicking because of the 'equivalancy of mass and energy', but isn't the term ''GeV/c2'' usually used to describe a particle's mass while ''GeV'' is used to describe its energy?--[[User:Dangerkeith3000|Dangerkeith3000]] ([[User talk:Dangerkeith3000|talk]]) 15:29, 22 October 2014 (UTC)<br />
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Sorry, felt it better to change "play 'hide and seek' with" to "know the current location of", because it read too as too anthropomorphic for the tone of the explanation. Like I don't play hide-and-seek with my house-keys, when they're temporarily unlocated. (Unless the world is weirder than I'm aware of, and the voices in my head are right after all!) Apologies if the hyperbole was the intent, and feel free to revert. [[Special:Contributions/141.101.98.247|141.101.98.247]] 14:53, 22 October 2014 (UTC)<br />
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The 4th paragraph begins with "Meagan's mention that "The death isn't even very serious"...". Shouldn't it be Ponytail, not Meagan? --[[Special:Contributions/108.162.216.111|108.162.216.111]] 16:28, 22 October 2014 (UTC)<br />
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:Or Cueball. Changing to "The comment..." [[Special:Contributions/173.245.54.195|173.245.54.195]] 17:36, 22 October 2014 (UTC)<br />
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Though of course this is a comic and not an actual transcript of a news conference or proceedings determining actual grant money, is there something significant missing or unanswered about the Higgs Boson that would require significantly more money (for e.g. a BIGGER COLLIDER!!!!!!!!)? Or is this rather a play at the "Find/Found" difference, and Randall just used the Higgs to make the point? I believe last I heard they found something that must be it, but I suppose further study was required to confirm it (or something)... [[User:Brettpeirce|Brettpeirce]] ([[User talk:Brettpeirce|talk]]) 20:37, 22 October 2014 (UTC)<br />
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Maybe they just precisely determined it's momentum? {{unsigned|Craignelson7007}}<br />
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I don't read the "just one" reference as being just one death - "... to build a death ray.' 'Just one, though.'" certainly sounds like they built just one death ray. [[Special:Contributions/173.245.62.74|173.245.62.74]] 03:11, 24 October 2014 (UTC)</div>173.245.62.74https://www.explainxkcd.com/wiki/index.php?title=210:_90%27s_Flowchart&diff=69523210: 90's Flowchart2014-06-14T03:54:52Z<p>173.245.62.74: sorry, misread...</p>
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<div>{{comic<br />
| number = 210<br />
| date = January 15, 2007<br />
| title = 90's Flowchart<br />
| image = 90s_flowchart.png<br />
| titletext = Freestyle rapping is basically applied Markov chains.<br />
}}<br />
<br />
== Explanation ==<br />
<br />
Here you can see an apparent flowchart. However, it has non-standard notation. The oval normally represents either the start or stop of a process. Here, both the ''yes'' and ''no'' end up in ''stop'', which would normally imply that nothing below can be reached.<br />
<br />
Unless we are in the 90's, this doesn't matter, as there is nothing after the stop. But in the 90's, two processing paths follow, and both are from the lyrics of two hit rap songs from the 90's:<br />
*''{{w|U Can't Touch This}}'' by {{w|MC Hammer}}, says "Break it down. Stop! Hammertime."<br />
*''{{W|Ice Ice Baby}}'' by {{w|Vanilla Ice}} says "All right, stop. Collaborate and listen."<br />
<br />
In both instances, the sense of the lyric is that you should interrupt what you are doing, and switch to the new action. Interpreted in terms of flowchart terminology, we could consider that the 'stop' just pauses the main thread, and secondary threads are launched to perform the 'Hammertime' and the 'Collaborate' and 'Listen' activities. <br />
<br />
The title text compares {{w|freestyle rapping}} with {{w|Markov chain|Markov chains}}. Markov chains are mathematical constructs in which the state at the next time step is dependent only upon the current state and probability. This is somewhat similar to freestyle rapping, in which what is said next must bear some relationship to what was just said, but the "freestyle" part means that almost anything can be brought in (hence the probabilistic part).<br />
<br />
== Transcript ==<br />
:90's Flowchart<br />
:Start: The 90's?<br />
:No: Stop<br />
:Yes: Stop<br />
::Hammertime<br />
::or<br />
::Collaborate, Listen<br />
<br />
{{comic discussion}}<br />
[[Category:Flowcharts]]<br />
[[Category:Music]]<br />
[[Category:Charts]]</div>173.245.62.74https://www.explainxkcd.com/wiki/index.php?title=210:_90%27s_Flowchart&diff=69522210: 90's Flowchart2014-06-14T03:52:25Z<p>173.245.62.74: typo</p>
<hr />
<div>{{comic<br />
| number = 210<br />
| date = January 15, 2007<br />
| title = 90's Flowchart<br />
| image = 90s_flowchart.png<br />
| titletext = Freestyle rapping is basically applied Markov chains.<br />
}}<br />
<br />
== Explanation ==<br />
<br />
Here you can see an apparent flowchart. However, it has non-standard notation. The oval normally represents either the start or stop of a process. Here, both the ''yes'' and ''no'' end up in ''stop'', which would normally imply that nothing below can be reached.<br />
<br />
Unless we aren't in the 90's, this doesn't matter, as there is nothing after the stop. But in the 90's, two processing paths follow, and both are from the lyrics of two hit rap songs from the 90's:<br />
*''{{w|U Can't Touch This}}'' by {{w|MC Hammer}}, says "Break it down. Stop! Hammertime."<br />
*''{{W|Ice Ice Baby}}'' by {{w|Vanilla Ice}} says "All right, stop. Collaborate and listen."<br />
<br />
In both instances, the sense of the lyric is that you should interrupt what you are doing, and switch to the new action. Interpreted in terms of flowchart terminology, we could consider that the 'stop' just pauses the main thread, and secondary threads are launched to perform the 'Hammertime' and the 'Collaborate' and 'Listen' activities. <br />
<br />
The title text compares {{w|freestyle rapping}} with {{w|Markov chain|Markov chains}}. Markov chains are mathematical constructs in which the state at the next time step is dependent only upon the current state and probability. This is somewhat similar to freestyle rapping, in which what is said next must bear some relationship to what was just said, but the "freestyle" part means that almost anything can be brought in (hence the probabilistic part).<br />
<br />
== Transcript ==<br />
:90's Flowchart<br />
:Start: The 90's?<br />
:No: Stop<br />
:Yes: Stop<br />
::Hammertime<br />
::or<br />
::Collaborate, Listen<br />
<br />
{{comic discussion}}<br />
[[Category:Flowcharts]]<br />
[[Category:Music]]<br />
[[Category:Charts]]</div>173.245.62.74