User talk:Chinasaur/Archive1

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Happy editing, Isomorphic 07:20, 23 Feb 2004 (UTC)

Hi,

I'm a grad student in neuroscience at Stanford, and was wondering if you'd be interested in working together to overhaul the neuro pages on the wikipedia.

Cyberied 22:58, 25 Feb 2004 (UTC)

Dominant wavelength is an excellent article! I congratulate you. -- Cyan 20:52, 19 Mar 2004 (UTC)

HSV Color model

Thank you for fixing the formulas. Excellent.

But then you even went and looked at my code too. Well, all I can say is thank you very much indeed! :-)

I implemented (most of) your suggestions, though perhaps in a slightly different way than you might have been thinking. Take a look:

```# --> Using negatives for this generally not a good idea.
```

Using the value of None or a string value means more checks, since it's illegal to do arithmatic on a None value. If the previous formula had been correct, then no valid input would have given me a negative value on output. If it had been negative I could assume the output was really undefined. :-) Dirty? Kinda. And I should have checked input to be honest.

Now we've noted that h can take on negative values, so I can't use that dirty trick anymore. (not that I should have done that in the first place).

```      # --> And anyway, using the else statement is a better way to arrange
# --> the logic; easier to read, and one less comparison so probably
# --> more efficient.
```

There's an interesting argument. There's actually 2 schools of thought on that.

Listing 1:

```if foo: x=a
else: x=b
assert x==a or x==b, "whoops!"
```

Listing 2:

```if foo : x=a
if bar : x=b
assert x==a or x==b, "whoops!"
```
• Listing 1 does : Compare, Branch1, Branch2
• Listing 2 does : Compare, Branch, Compare, Branch

Just 1 more instruction (and compares can be cheap).

So where's the beef?

Well, listing 1 assumes that if foo doesn't hold, then bar must hold (and vice versa), but you don't ever mention bar.

In fact, if *neither* foo *nor* bar hold true, then it will assume that bar holds true. The assertion is never raised

In Listing 2, both foo and bar are mentioned. Should your assumptions be wrong, and neither foo nor bar happened, then the programme will be able to raise an assertion to warn you.

I like Listing 2 better than listing 1 for that reason. :-)

There's a slight variant on listing 2 which I use in the programme:

Listing 3

```x="undefined"
if foo:
x=a
if bar:
x=b

return x
```

Listing 3 will explicitly test both assumptions, and return the string "undefined" if neither holds true.

Listing 4

```if (foo or bar):
if foo:
x=a
else:
x=b
else
x="undefined"

return x
```

listing 4 should do the same thing, now using if ... else. I'm not sure if that's really clearer though! :-)

Let's see how that does branching

• Listing 3 does set, compare, branch, set, compare, branch, set, return
• Listing 4 does compare or compare, c1branch 1: {compare2, c2branch 1 : set , c2branch 2 : set}, c1branch2 : set, return

Don't be mad at me if I made a typo on listing4, it's tricky. :-)

Hopefully that tells you something about views on if...else that you hadn't seen before. I'm sure it's a holy war somewhere. :-)

Thanks again for looking at my horrible python code! :-)

Have a nice day! Kim Bruning 10:30, 7 Apr 2004 (UTC)

Thanks to your exceptional help, I managed to update all of THIS:

I've credited you on Talk:Color Thanks for your time! Kim Bruning 14:36, 7 Apr 2004 (UTC)

In regard to your inline (‽) question about shibboleths on the Prescription (linguistics) page, I presume the person who used the term was referring to the fact that many prescriptionist rules function as shibboleths, in that only certain groups are capable of using them correctly. I've fiddled with the "shibboleth" entry a bit; tell me if you think it makes sense in the context of the prescription article. -- कुक्कुरोवाच|Talk‽ 06:42, May 21, 2004 (UTC)

hello

Hi Chinasaur! I'm glad to see someone else is familiar with Bluebeard. Actually it would make a great double-bill with Salome (which I would like to see the SF Opera do--did you catch the Electra a few years back?) Be well, Antandrus 05:40, 5 Jul 2004 (UTC)

:By the way, have you seen the Teldec video movie version? Pretty good watching, although the traditional staging gets thrown out the window. --Chinasaur 05:53, 5 Jul 2004 (UTC)

No I haven't--is it available on DVD? (presuming you mean Bluebeard's Castle) Sounds great though! Since the drama is internal it probably doesn't need elaborate staging, in fact it might help not to have too much distraction. I like your edits to the article, btw. I was trying to decide whether or not to put any of my personal interpretation of the piece into the article when I first wrote it, and decided not to--you did a good job though. Incredible psychological study of a relationship and places you cannot ever go. --I also saw that Elektra (Nov 1997). Did you catch the Busoni Doktor Faustus this weekend? Best, Antandrus 06:11, 5 Jul 2004 (UTC)

Nice job on the rewrite. Gives me chills just thinking about "door six." Be seeing you! Antandrus 06:24, 5 Jul 2004 (UTC)

Seikilos

OK, now I'm truly impressed! I had no idea anyone else knew about Seikilos. (And you read my mind, because I was just thinking about writing a little bit about it!) Are you interested in ancient Greek music, and if so do you have an idea where it can fit in the Wikipedia scheme of things? Right now "history of western art music" begins with Pope Gregory and "Medieval music." I think Ancient Greek music needs its own article with numerous other subarticles, none of which even have stubs yet. Antandrus 20:50, 5 Jul 2004 (UTC)

Bobtail squid

Awwww! Look at the cute little guy! *grins* - UtherSRG 11:33, 29 Jul 2004 (UTC)

Nobel Prize winners

Hey Chinasaur! Thanks for your great work on all the biology articles. I noticed you have Georg von Bekesy on your "To work on" list. With your interest in vision and the retina, I thought you might want to take a look at Allvar Gullstrand, Ragnar Granit, Haldan Keffer Hartline, and George Wald. Some of these are okay, but may need some fact-checking; the Granit article is little more than a stub. Please post any replies on my talk page. Keep up the good work! Sayeth 15:41, Aug 16, 2004 (UTC)

Hydrofoil vs. Hydroplane

See this link for an example of hydroplanes: [2] -Joseph 18:11, 2004 Aug 25 (UTC)

Wow, those things look like some crazy good times. I was basing my hydroplane==hydrofoil on the dictionary though, so it may still be a valid point. --Chinasaur
Yeah, I'm just saying that "hydroplane," in a purely nautical sense, means something else. -Joseph 18:31, 2004 Aug 25 (UTC)

Monoecious

Hi Chinasaur - Your editing at Monoecious is good in some aspects, but it has become very Angiosperm-centric in its terminology (flower, stamen, carpel, etc); it should be re-worded to include Pinophyta etc as well (many of which are also monoecious) - MPF 20:16, 7 Sep 2004 (UTC)

I'm hardly an expert in botany/horticulture subjects; I just tried to make sense of what I've seen in books and on the web. Thanks for the warning about the pinophyta; I'm not too familiar with their sexual organs but I'll try to be more general. Let me read up a little and then I'll think about fixing it; in the meantime if you have suggestions for more general terminology that would be great. --Chinasaur 00:15, 8 Sep 2004 (UTC)
Thanks; will do if I get the time - MPF 14:06, 8 Sep 2004 (UTC)

Binaural

HRTFs are for recreating monaural cues, not relevant to binaural. also deleted stuff that's in the binaural recording article

I'm not an expert on HRTFs, but I would think that it is precisely the differences between the HRTFs for the right and left ears that allow for binaural auralization from monophonic recordings/synthesized sounds 1. More here 2. -- Tlotoxl 09:44, 27 Sep 2004 (UTC)

See the soon to be published article at sound localization. You're right, HRTFs are relevant to binaural processing, but they aren't primary; inter-aural time differences are much more significant. --Chinasaur 09:51, 27 Sep 2004 (UTC)
Surely interaural time difference is captured as part of the HRTF (though may be more efficiently implemented separately from the otherwise huge HRTF FIR filter, from what I guess/gather). In any case, it sounds like you know what you're doing so I like forward to seeing the new sound localization article. Certainly binaural and the related articles deserved some attention. Oh, I see sound localization is ready now. Will check out. -- Tlotoxl 10:05, 27 Sep 2004 (UTC)
My understanding is that HRTFs focus on frequency filtering as a function of source location. Time information is not something that HRTF people worry about I don't think (at least not in biology). The time scale of inter-aural time differences is probably too long relative to the frequencies to be resolved in the low end of the frequency transform. Not sure if this argument makes sense mathematically, or if it is answering your question. My understanding is all from the biology side; my signal processing understanding is not so great. --Chinasaur 10:39, 27 Sep 2004 (UTC)
It is true that HRTFs filter frequency as a function of source location, but it is important to realize that they have both an amplitude and phase component. Group delay, the total delay of a signal at a given frequency, is equal to the slope of the phase response of the HRTF (or filter in general) at a given frequency. The difference in group delays between left and right ears will therefore be the interaural time difference. Of course the length of interaural time delay reproduced by an HRTF is limited by the length of its impulse response (and the resulting FIR filter), but I think most HRTFS are at least several thousand samples long (so 10s of milliseconds long) -- this should be enough to capture the interaural time delay. Since not everyone has a computer capable of convolving such long impulse responses with an input signal in real-time, though, I would imagine that many real-time solutions use delay-lines to introduce interaural time differences and then use much lower order filters. Don't know, though. Egads, sorry for the ramble. Anyway, I think your article is an improvement, regardless. -- Tlotoxl 10:50, 27 Sep 2004 (UTC)
I don't really get it; I don't see ITD as being a frequency dependent thing; shouldn't the time delay between two ears be the same for all frequencies? In terms of the phase offset results, I don't think this is on a time scale a human observer is going to notice, even for a very coherent, low frequency signal. Trying to use the terminology you have just introduced to me: if the group delay necessary to capture the ITD is much more than a single phase of the signal, then how could you use it? Is what I'm saying making any sense? Time for bed. --Chinasaur 11:15, 27 Sep 2004 (UTC)

Complementary colors

I agree that the article is inadequate. I don't know the topic, so I can't fix it. But I have these two comments:

• You wrote complimentary color, with an i. I hope that's just a typo and you know that complement with an e and compliment with an i are two different words that mean quite different things.
• Is there really such a thing as "imaginary colors"? Can you explain?

Michael Hardy 01:15, 5 Oct 2004 (UTC)

Hi. Thanks for you lengthy discussion of imaginary colors. Maybe your comments could evolve into a new article? Michael Hardy 23:20, 10 Oct 2004 (UTC)

Phase perception

Regarding your comments on phase perception: (in Talk:Color) But actually I'm fairly certain that this is true of all biological color vision systems. I just can't think of a good way for any biological system to use phase information constructively (except in very special cases), so I would assume none do it. Thoughts?

-Not only is phase information not terribly useful.. I can't think of any way a biological system could retrieve phase information. For visual color, the time from wave trough to crest is on the timescale of femtoseconds, 1E-15. There is nothing in biology, or chemistry even, which can react that fast. Its pretty much accepted in physics that 'the only thing fast enough to measure light, is light.'.. That is, the only way to get phase data is through interference.

One practical example of that would be femtochemistry (see Zewail, nobel prize winner), which (in simplified terms) uses interference to measure chemical reactions (which are slower than the femtosecond timescale).

/End of lesson ;-)

Good point; I hadn't thought about the time scale issue. Still I'm not completely convinced that the time argument rules out light phase processing by a biological system. This is mostly just to play Devil's advocate, but if you look at thin-film optics in biological structures like butterfly scales, or the tapetum lucidum you can see that there is the possibility of structured biology at the scale of light wavelengths. So definitely I would say there are interference possibilities, although making the structure sensitive to more than a few wavelengths and phases through interference is hard to imagine.
On the other hand, wavelength scale structures may provide a way to get phase information without interference or femtosecond processing. I don't know enough about the optical activity of chemical absorbers like retinol to be able to say how this would work, but you can imagine that if light absorbing pigments were arranged in structured microlayers and had absorptional preference for the wave at a particular phase (this is the part I'm sketchy on) then it wouldn't be necessary to process extremely quickly, only to have a prolonged response and calculate a difference between responses based on the distance separation of the pigments. What do you think? Could we get light phase info by matching the wavelength of light, rather than trying to match the timescale? --Chinasaur 19:17, 16 Oct 2004 (UTC)
Funny how these issues keep coming up with me. Check out the discussion of binaural above; you might find that interesting and might have some input. --Chinasaur 19:20, 16 Oct 2004 (UTC)

Did you know

Hello, I'd like to inform you that "Did you know" is not for stubs. If you'd still like to see your submitted articles featured, please try to get them expanded to over 1000 bytes. [[User:MacGyverMagic|Mgm|(talk)]] 08:46, Nov 29, 2004 (UTC)

Ah yes, I should have remembered. Good thing I was (uncharacteristically) unbold about adding them to the main page myself... --Chinasaur 08:49, 29 Nov 2004 (UTC)

Mapquest template and Mapit-US-streetscale template

One of two things:

1. Since yours is based on solely latitude and longitude, "US" may not be entirely approprate for the title, seeing as Mapquest can map worldwide.
2. Just wanted to let you know there is an existing Mapquest template. Template:Mapquest

-- AllyUnion (talk) 08:16, 1 Dec 2004 (UTC)

Thanks; it's good to get responses about this. I think everything you've brought up is consistent with my scheme: there are separate MQ only templates that can be used for mapping through lat/long ({{MQ-dec}} and {{MQ-deg}}) or address name ({{Mapquest}}) throughout the world. But my new templates also include some other resources that only work in the U.S., and generally I want these templates to be dynamic and updatable with the latest resources, so it seemed to make sense to limit it. For other countries, I would recommend using the existing MQ templates as that's about the best that can be done. If there are other non-U.S. specific resources then new templates can be made to use those, but for now I think mapquest and british grid system (not compatible with lat/long) is about all we have outside the U.S. (as far as I'm aware). Let me know if you have other concerns! --Chinasaur 11:58, 1 Dec 2004 (UTC)

Article Licensing

To allow us to track those users who muli-license their contributions, many users copy and paste the "{{DualLicenseWithCC-BySA-Dual}}" template into their user page, but there are other options at Template messages/User namespace. The following examples could also copied and pasted into your user page:

Option 1
I agree to [[Wikipedia:Multi-licensing|multi-license]] all my contributions, with the exception of my user pages, as described below:

OR

Option 2
I agree to [[Wikipedia:Multi-licensing|multi-license]] all my contributions to any [[U.S. state]], county, or city article as described below:

Or if you wanted to place your work into the public domain, you could replace "{{DualLicenseWithCC-BySA-Dual}}" with "{{MultiLicensePD}}". If you only prefer using the GFDL, I would like to know that too. Please let me know what you think at my talk page. It's important to know either way so no one keeps asking. -- Ram-Man (comment| talk)

On main page talk, (1), you said: " I also worked up a My Watchlist RSS script, but ultimately I decided this wasn't all that useful. --Chinasaur 06:48, 25 Nov 2004 (UTC)"

Is this true? This has been much asked for, but the developers have argumented that I'd take a lot of cpu from servers and be hard to protect - the watchlist is private. Does you solution, practically, work? That would be great!

The relevant meta page is meta:Syndication_feeds, where I now see that Watchlists as RSS are on the roadmap. ✏ Sverdrup 21:17, 15 Dec 2004 (UTC)

The only advantage I can see is that you could use the script as a middleman to do some additional processing on your watchlist, so for example don't bother to include edits from "trusted" usernames. Greater control over what appears in the watchlist is something that should be incorporated into MW.
Anyway, I have the source if you want to see the client I cooked up. But one other user had trouble even getting it to run. --Chinasaur 18:13, 17 Dec 2004 (UTC)

Millenium Actress

I looked over the page for Millenium Actress, and it looks good to me. It might be useful to add a list of voice actors. BTW - thanks for your work on the lotuses. Sorry for the late reply, I wandered off for November and most of December. Munkymu 17:59, 21 Dec 2004 (UTC)

Onegin stanza

Doesn't it make sense to have information on the Onegin stanza in the article on Onegin, because it's directly releventant to it? Number 0 11:02, 18 Feb 2005 (UTC)

I thought it was worth splitting since it was getting into some technical details that I doubt were very relevant to most readers of the Onegin article. And I think it has more room now to expand if people want to talk about other works written in that form or other nuances such as comparing it to Italian sonnet form, etc.. Finally, it's nice to have a separate page so that it can be linked to directly from poetry and sonnet articles; I really don't like linking to headings within articles. --Chinasaur 18:57, 18 Feb 2005 (UTC)

Thought about it over the weekend and I think you're probably right, but I'll put some more information on the Onegin page too. Number 0 12:48, 21 Feb 2005 (UTC)

Thank you

Thank you for starting Wikibooks:Errata. This could develop into a really useful resource. --DavidCary 19:10, 28 Feb 2005 (UTC)