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May 20

usefulness of complex-input FFTs in audio spectral analysis

Since I've implemented a feature to treat stereo audio as complex numbers in one of my own audio spectrum analyzer projects over CodePen, I'm curious about whether or not is there any useful cases of complex-input FFTs as in the case of I/Q signals on any SDR-related stuff, being performed in typical two-channel audio? BTW, I'm not talking about the performance benefits of using one complex-input FFT to visualize two spectrums for each channel, which is the same, plus the "unscrambling" operation to make it look like individual FFTs of each channels. 2001:448A:3070:DF54:98E8:4EDF:605:8379 (talk) 00:59, 20 May 2024 (UTC)

The Discrete Fourier transform (DFT) that converts a sequence of data samples to a set of complex coefficients of frequencies is directly applicable for spectral analysis. The frequency domain representation of the input sequence allows many useful signal processes, including frequency-selective filters, and the filtered frequency coefficients can be converted back to real data by means of an Inverse DFT.

Mathematically a DFT converts a sequence of N complex numbers $\left\{\mathbf {x} _{n}\right\}:=x_{0},x_{1},\ldots ,x_{N-1}$ into another sequence of complex numbers, $\left\{\mathbf {X} _{k}\right\}:=X_{0},X_{1},\ldots ,X_{N-1},$ which is defined by:

Discrete Fourier transform

$X_{k}=\sum _{n=0}^{N-1}x_{n}\cdot e^{-i2\pi {\tfrac {k}{N}}n}$ ()

The operation is computationally intensive as N must be large enough for a required frequency resolution but it can be speeded by the digital FFT (Fast Fourier transform) algorithm. A further simplification is that for a real signal such as audio from one microphone, only real values of $\{\mathbf {x} _{n}\}$ need be processed i.e. the imaginary value of each sample can be zero. Such real-data-in, complex-values-out usage of FFTs is commonplace. However it is useful to note that the zeroed imaginary data points potentially offer themselves as a second, independant data stream. The OP cites a .pdf that correctly demonstrates that two stereo audio signals can be combined as real and complex inputs to a single FFT. That one FFT can process two signals without interference is demonstrable by recovering the signal samples in an IDFT thus:

Inverse transform

$x_{n}={\frac {1}{N}}\sum _{k=0}^{N-1}X_{k}\cdot e^{i2\pi {\tfrac {k}{N}}n}$ ()

While the economy of using a single FFT to process both stereo channels is obvious it is less obvious that any two real input data streams may be applied as there really is no interference between them. Noting that the algorithms for forward and inverse DFTs are similar, a system programmer will usually write code that is reusable for both and has provision for complex input data, even if that is superfluous for the DFT, because it is always demanded for IDFT. Apart from audio applications, an IDFT/DFT pair is useful as digital Codec in digital carrier Phase-shift keying modulations BPSK (real values) and QPSK (complex values). Philvoids (talk) 19:58, 20 May 2024 (UTC)

@Philvoids Thanks for a lengthy explanation but what I meant by "complex-input FFTs" as in this CodePen project is simply treating stereo pairs or even Mid/Side representations as complex numbers and do no postprocessing at all and simply display two graphs with different colors; the first one is as usual as regular FFT spectrum, and the second graph is exactly the same but the ordering of FFT bins is reversed since we provided an FFT a complex-valued input, the output is no longer conjugate-symmetric, which could display stereo FFT in a different way (one graph is higher in amplitude than other means being closer to 90° out-of-phase, either clockwise or counterclockwise) and might have practical uses or is it? 114.5.253.252 (talk) 18:50, 21 May 2024 (UTC)

While agreeing that a single FFT can treat samples of a stereo pair as complex numbers, I have not found more useful references than those already given for your on-going project; it feels more like a "solution looking for a problem" than a "problem looking for a solution"! We also cannot speculate or know whether your interest is theoretical curiosity or you have an application or product plan. Philvoids (talk) 03:04, 22 May 2024 (UTC)

I agree with @Philvoids and this DSP related thread about the same topic in regards of treating stereo sample as complex numbers, I'm just curious why people bringing up some performance improvements of stereo FFT by treating an input as complex numbers for a single FFT and doing "unscrambling" operation afterwards instead of other niche stuffs using same FFT as for I/Q radio signals but for audio? Sure, it could identify TSAC-encoded music with the same complex-input FFTs as for I/Q signals as "holes" in one (red) graph at higher frequencies (around 15kHz) as in this image on this HA thread about the same topic. 114.5.249.110 (talk) 21:40, 22 May 2024 (UTC)

Calendar change and historical procrastination

Initially, only a few countries already switched to the Gregorian calendar in 1582. But then, as the centuries go by, more and more countries followed the calendar change, including Great Britain in 1752. This continued all the way until the year 1923 in Greece.

So, could such a long waiting be considered as a kind of procrastination? Procrastination means putting off tasks to a later date, and the task relevant to this question is that of switching to the Gregorian calendar. One of the negative consequences is that the longer you waited, the more days you had to drop from the Julian calendar. Changes in the 1500s, 1600s, 1700s, 1800s, and 1900s required 10, 10, 11, 12, and 13 days to be dropped, respectively (note that 1600 was a leap year in both calendars, so no additional day needs to be dropped until 1700).

GTrang (talk) 16:21, 20 May 2024 (UTC)

It could depend on each country's rationale for resisting. One possibility could be anti-Catholic bias. ←Baseball Bugs ^{What's up, Doc?} carrots→ 18:03, 20 May 2024 (UTC)

Specifically, the head honchos of the Eastern Orthodox Churches felt that adopting this calendar proclaimed by a papal bull would be seen as admitting the supreme authority of the head honcho of the Roman Church.  --Lambiam 19:21, 20 May 2024 (UTC)

We must be patient. An agreement on the term honcho picked up 1947-1953 by U.S. servicemen from Japanese hancho "group leader" has still not been reached in catholic churches since the East–West Schism of 1054. Philvoids (talk) 21:01, 20 May 2024 (UTC)

This is a little off-topic, but does anyone understand why they didn't just say, OK, we're changing the schedule of leap years going forward, but we're not dropping any days from the current calendar? It's weird to me that they preferred to set the correlation between seasons and the calendar to something it hadn't been in living memory. I could maybe understand if it were a date-of-Easter thing, but Easter has never gone by the solar calendar anyway, so that also doesn't make sense. --Trovatore (talk) 19:32, 20 May 2024 (UTC)

325AD was important, Christmas (second most important after Easter) is solar and Easter falling up to 7+30 or 7+29 days later than the Sunday after the first spring Full Moon and up to ~10 days later in spring than could in 325 made them feel icky. Sagittarian Milky Way (talk) 00:45, 21 May 2024 (UTC)

On a smaller scale, we have the 19-second difference between GPS time and International Atomic Time, and the running difference between those and Coordinated Universal Time, occasioned by one of the worst ideas in the history of human timekeeping. When they finally get rid of the stupid thing and treat the pose of the Earth as just another ephemeris, like they should have done for at least fifty years, it will be interesting to see whether they attempt some unification, or just have three separate clocks with a fixed difference of a few seconds. --Trovatore (talk) 19:43, 20 May 2024 (UTC)

That would be a sin and make astronomers and some sailors feel icky. Astronomers deal with way more than three clocks per location and the 70 second difference from the endlessly slowing spin crossing 24 SI hours in like 1820 all the time, suck it up programmers. Sagittarian Milky Way (talk) 00:45, 21 May 2024 (UTC)

It's the astronomers who need to suck it up and treat the Earth's pose as just another ephemeris. --Trovatore (talk) 00:49, 21 May 2024 (UTC)

The astronomers have to do that anyway, because leap seconds only get you to the nearest second or so, and that is often not good enough. The UT1-UTC ephemeris can be predicted pretty well into the future, except for leap seconds. Leap seconds throw it off completely because they are a political decision and cannot be reliably predicted beforehand. They also introduce a discontinuity so that you have to be careful when interpolating. [1] So getting rid of leap seconds would probably make it easier for the astronomers. (It might still be true that it would also make them feel icky.) —Amble (talk) 02:46, 21 May 2024 (UTC)

According to the linked article, the current plan after leap seconds are ended by 2035 is either for a leap minute or leap hour in the future, so I'm not sure it makes sense to unify them when they're going to drift again in the future. I mean it would be slightly cleaner since whatever they chose future changes would be in that whole number and so the difference would always be in that number of units. OTOH, it doesn't seem like that number is that significant for most purposes, so I wonder if they will care. Also I wonder if the more likely plan if it's decided to keep the difference in whole units, might be for the first "leap minute" or "leap hour" to actually be slightly less or more than an actual minute or hour and use that to hit on a whole number of unit. Note that there's some suggestion that a negative leap second may be coming perhaps before 2035 and so that may need to be dealt with either by eliminating leap seconds sooner, or simply skipping it even if it's technically required under the current system; rather than risk finding out what software bugs may exist for something which won't be needed for much longer [2] (although assuming the leap minute or leap hour ideas go ahead, it's theoretically possible they would need it). Nil Einne (talk) 11:06, 22 May 2024 (UTC)

BTW, do astronomers really have much to do with it? While not well discussed, from what is discussed and common sense I think the bigger issue may be the desire of some countries for UTC to be fairly tied to TAI but also have 1200 in their local time zone (which is tied to UTC) be roughly midday (depending on their local timezones) rather then for it to potentially be midnight sometime in the distance future. (Well that's a fairly distant thing, but it sounds like some are even unhappy with it diverging by even an hour.) The counter argument that there is already so much variance given the spread of timezones etc seems to have won out for the leap minute or maybe even the leap hour. But as this time, I think they're still unhappy with the eventual possibility it could indeed be midnight during 1200 in the future. Nil Einne (talk) 11:19, 22 May 2024 (UTC)

Any large discrepancies would be way in the future, and barring enormous advances in life extension, are not going to affect us. Anyone they will affect would be born in a world in which it's not that different, so they'll have plenty of time to get used to it.

Without leap seconds, a person who lives 120 years will see nominal average sunset times shift by, what, 90 seconds or something? Come on, there's no way this is seriously a problem. Leap seconds are just a really really bad idea, and hopefully they'll expunge them with all deliberate speed. --Trovatore (talk) 18:53, 22 May 2024 (UTC)

Anyone so irritated by leap seconds needs to use GPS time or an International Standard Computing Time that equals UTC at the conference creating the standard or maybe TAI. If done soon that would give many, many months to reprogram before the next leap second (Earth's recently been spinning close to the UTC accumulation and unusually close to the SI rate based on human knowledge right before the slowdown was first measured which was based on 18th and 19th century position measurements). Computers already convert UTC to time zone, just use atomic time and leave UTC alone. Also we have to make time impure for all time cause idiots didn't change Unix time to the actual number of SI seconds by the 1990s when computer clocks became accurate enough or 2001 when they made 2100 a leap year? Leap seconds are perfect! Pure unsmeared SI seconds except 1 second every few years on average (6 months happened once) and it can't more than 0.9 seconds wrong. Also you do know it's quadratic right? People shouldn't be boiled to wrongness they wouldn't accept all at once in the same lifetime like the leap hour in 2600 (fucking night owls' sleep by making 8am earlier in the day till it happens. New York Cityans who could wake up 11.5+ hours after sunset and 0.5+ hours after sunrise without risking lateness would have to wake up ≤11 hours after sunset and (c. Jan 4 and Nov 5-6 DST) at sunrise or before like a weirdo morning person). If I didn't grow up in it I'd think daylight savings is an abomination instead of mixed feelings more pro than con (DST also fucks sleep but I never knew anything else). Sagittarian Milky Way (talk) 22:00, 22 May 2024 (UTC)

Time is time; the Earth moves somewhat irregularly with time. There is no reason our timekeeping needs to follow the Earth's foibles.

Just freeze the current difference between UTC and TAI now and forever, and then we can keep using UTC. Sure, our great-to-the-nth grandchildren may be getting up at 3 AM or 3 PM or whatever, and they'll think the name "midnight" is kinda weird and that time references in old literature don't make a lot of sense, until someone remembers that it's drifted since then. Of course human schedules will adjust to move with the Sun, not with the clocks.

So what? It's a little like the scene in It's a Wonderful Life where George Bailey is offered the amazing salary of $25,000 per year, beyond dreams of avarice, and is briefly tempted. You can watch that and understand it; even if you don't know just how much that would buy you, you understand it's a lot. --Trovatore (talk) 22:15, 22 May 2024 (UTC)

9 to 5 has never been 10 to 6 or 11 to 7 in double war time, it'd reach insanely discriminatory levels before it'd be 10 to 6! Schools discriminate against teens, industry lobbyists discriminate against night owls (the theater, nightlife etc lobbies are collectively weaker than the golf, bike etc lobbies). We expanded DST as much as we could (Nov 6 very competitive with latest post-Nov day in sunrise lateness at 40N near the meridian), we're used to it, it delays ugly June dawn, there's no room for more. Enough circadian rhythm bigotry. Sagittarian Milky Way (talk) 04:51, 23 May 2024 (UTC)

Delays the June dawn? Nonsense. The dawn is when it was always going to be. We're just putting a different number to it. You don't have to let that number control when you do things; it's just a number, not a cop.

Now, granted, sometimes you have constraints based on when other people want to do things. But again, there's no need for them to schedule them according to any particular time coordinate. If you don't like when they want to do it, well, push back!

I'm reminded of when I had a summer job working for IBM in Tucson. We had some flexibility in our hours, but the people I was riding with wanted to do the 7:00 AM to 3:42 PM schedule (IYKYK on the 42 minutes). Insane, right?

Not so much. Arizona doesn't observe DST, so that's 7:00 AM Mountain Standard Time, which would be 8 if they observed DST. Also, Tucson is further east in its time zone than Los Angeles, so you can think of it as 8:30.oops, got that bit wrong. Still early for my taste, but not totally unreasonable.

Similarly, the Spanish famously do everything late. But do they? Madrid is west of London, but shares a time zone with Vienna. By the Sun, they're...still pretty late, but not quite as much as you might think.

The point is that human schedules are a self-organizing system, not under central control, and respond to what you might call "market forces", which in the long run will optimize them to the position of the Sun, not to a number on the clock. --Trovatore (talk) 06:23, 23 May 2024 (UTC)

Yes you don't have to be an astronomer or sextant user to have a desire for SI seconds with an extra second announced in advance to keep it approximately the closest second, it's unsurprising if pro-leap second astronomers and sextant users outnumbered by other pro-leap second humans through sheer numbers. Midnight at 1200 is insane, that's 12 hours wrong even Anchorage doesn't use California time for convenience (2 hours wrong) and they're used to it never getting dark then just a few hours of day. If the south horizon's high enough the city doesn't touch sunlight for weeks and the north horizon's only lit a few hours. Leap minutes would be an unneeded complication increasing the number of things that can't use civil time without extra work fixing it back to mean solar time of the multiple of 15 longitude. For instance Earth spins 11.7 longitude seconds in 0.78 time seconds (eyeballing the most it's been wrong so far on a graph, though they stopped jumping the gun so much over time so it doesn't get that bad anymore, probably they could not pad it at all without risk of it speeding from a 6 month forescast of c. 0.5 seconds to over their 0.9 second mandate in only 6 months). It would hardly affect sextant accuracy to use British Standard Time or Iceland Time (they're UTC all year), if it was leap minute even if it switched at 30 instead of 60 that'd be 7.5 minutes wrong (up to almost 9 land miles/14km). That's as inaccurate enough to put a very low island beyond the horizon from up to tens of yards up, several times the horizon distance of standing on a perfectly flat Earth and not even close to a passing score for sextants, eagle-eyed Tycho Brahe did 14 times better in the 1500s with just a 1.6 meter wood and his eyeballs. Sagittarian Milky Way (talk) 15:06, 22 May 2024 (UTC)

The non-computerized sextant user already has to carry charts based on the date and latitude and such, right? Let him keep one more table, which is the number of seconds to add or subtract in a given year. It doesn't change that much so he can probably just remember one extra number and it'll be good for some time. Problem solved. --Trovatore (talk) 19:44, 22 May 2024 (UTC)

Stop using UTC for computers. Problem solved. Or maybe leap seconds could be abolished and the second could be changed once it's crossed 0.6 seconds, to the value estimated to keep it less than 0.6 seconds wrong the longest. Would that be that bad? The scientists who need to specify this second is 86,400.002/86,400.000ths the early 2020s second probably have complex work already. Sagittarian Milky Way (talk) 22:15, 22 May 2024 (UTC)

And pre-electric navigating tools will survive solar and military electromagnetic pulses that would melt all metal too many kilometers long and probably fuck all navigation that needs electricity. They'd survive an anti-satellite or computer virus war. Sagittarian Milky Way (talk) 22:31, 22 May 2024 (UTC)

If you want to avoid leap seconds, but keep the local time in sync with the sun, you can just periodically shift all the time zone boundaries. Instead of a leap second, you’d shift the boundaries by 15 arc-seconds of longitude, which is about 300 m at the equator. You can call them leap-meters. I suspect this idea will not catch on. —Amble (talk) 15:52, 22 May 2024 (UTC)

That would decouple time zones from longitudes that are multiples of 15 and no one would want to move the line till most of a metro area or at least rural county has passed through it. Sagittarian Milky Way (talk) 22:38, 22 May 2024 (UTC)

The biggest headache from leap seconds is that they are incorporated into things like Unix time / posix time that really ought to be a continuous count, or at least monotonic. At a leap second, the same timestamp gets replayed and no longer corresponds to a unique moment in time. Whatever we end up doing with leap seconds, leap minutes, and leap hours, all of the not-quite-continuous-count time coordinates need to be banished ASAP. Then you’d only need to worry about leap seconds when converting a single, continuous time coordinate into a formatted local time. —Amble (talk) 15:52, 22 May 2024 (UTC)

Stop using UTC for things where monotonicity is important and leave UTC as it is. Sagittarian Milky Way (talk) 22:38, 22 May 2024 (UTC)

Sweden maximized the inconvenience by procrastinating several times in different directions: Swedish calendar. First they decided that the big jump was too much to do all at once, so not to switch all at once, so they spread it out over the course of several decades, by simply skipping leap years. Then they got distracted and forgot to forget some of the leap years. Then they decided the whole thing was a lot of trouble, and switched back to the Julian calendar by observing a double-leap-year, which had a February 30. Not too many decades after that, Sweden finally switched to the Gregorian calendar in the usual way, by skipping a block of days all at once. Some of these decisions have got to be worse decisions than leap seconds... —Amble (talk) 20:28, 20 May 2024 (UTC)

I did say "one of the worst". --Trovatore (talk) 20:38, 20 May 2024 (UTC)

That’s fair! In the history of timekeeping there have been enough questionable decisions that it would be difficult to pick just one. —Amble (talk) 00:18, 21 May 2024 (UTC)

The advantage of stopped clocks is that they are right twice a day in all systems of timekeeping.  --Lambiam 08:38, 21 May 2024 (UTC)

I feel like you're missing a pretty obvious counterexample. --Trovatore (talk) 20:19, 21 May 2024 (UTC)

A clock running backward is even better! —Tamfang (talk) 22:34, 21 May 2024 (UTC)

I wonder why no state did it by dropping each 31 for a couple of years. —Tamfang (talk) 22:35, 21 May 2024 (UTC)

That would have put them into an analogous situation that Sweden faced. In those intervening years they would have been out of synch with both the Julian and the Gregorian, and thus out of synch with every country in the world that uses any version of the Western calendar. Hopeless confusion would have ensued. Referring to those dates in later years would have required a tripartite code: Old Style, New Style, and Our Special Temporary Style. Life's too short for that sort of shit. -- Jack of Oz ^{[pleasantries]} 22:58, 21 May 2024 (UTC)

Internet Archive

When archiving web pages with an option to switch between metric and imperial units, in many times the imperial units come to the archived version. Why does this happen? It may occur when the menus have imperial option in just one place. Which is the reason for that? --40bus (talk) 19:47, 20 May 2024 (UTC)

The archiving service loads the page from the web, not from your browser. It does not know what cookies you have set.  --Lambiam 08:23, 21 May 2024 (UTC)

May 21

Any free versions of these issues online?

I'm not posting on WP:RX because I don't need the articles, as I already have the material. I'm trying to link to the pages for use in an article on a footnote.

• The Saturday Evening Post. 212 (42): 115. April 13, 1940.
• Woman's Home Companion. p. 59. November 1940.
• Vogue. p. 58. February 1, 1941.

Thanks. Viriditas (talk) 23:25, 21 May 2024 (UTC)

@Viriditas: for Vogue: [3] requires a login to view the issue but it looks like there is no cost to create account RudolfRed (talk) 02:55, 22 May 2024 (UTC)

Good news! Thank you. Viriditas (talk) 02:57, 22 May 2024 (UTC)

@RudolfRed: I've tried everything, but that Vogue site does not appear functional at all. Try logging in and reading an article from 1941. It doesn't work. Viriditas (talk) 23:39, 25 May 2024 (UTC)

May 22

Measurement units

Are there any recent books with not just contemporary human-scale units but many others all with conversions all listed in size order in sections named mass, acceleration, inverse length (several units like diopter are inverse length) etc (no wasting space blabbing for half the book instead of more kinds of units i.e. Meccan wine gallons and magnetic fluencivity). Maybe it could show multiple conversions per unit but one conversion per unit to either SI or one of the less obscure non-SI units would be sufficient. It'd be nice if the conversions had ~8-24 digits if unavoidable (some unit to different measurement system conversations could get an exact symbol with only a fqew digits (some without fractions or repeating decimal overlines like survey inch=(1/39.37) meters)). Sagittarian Milky Way (talk) 04:30, 22 May 2024 (UTC)

I imagine such a book would struggle to find a publisher in the age of the internet. I did look through all the online unit converters on the first page of a DuckDuckGo search, and none of them cited any sources for their conversions, although several seemed very robust.

I'm not sure how interested you are in premodern units (I'm unfamiliar with Meccan wine gallons and magnetic fluencivity), but if you're looking at premodern units you should keep in mind that how we think of them in the present is usually an approximation of what their original value was, even if the value was rigorously defined at some point instead of a "just about". The recent book Eratosthenes and the Measurement of the Earth's Circumference (c.230 BCE) (Matthew, 2023) devotes an entire chapter to figuring out the size of the unit used in the ancient experiment. Meanwhile I've at least twice had cause to cite Loewe, Michael (1961). "The Measurement of Grain during the Han Period". T'oung Pao. Second Series. 49 (1/2): 64–95. doi:10.1163/156853262X00020. JSTOR 4527501. That article goes into significant depth about the changing value of different measurements of volume and where the historical sources allow us to estimate the measurements against each other and against modern units. Sometimes we get lucky and there's an extant prototype that allows us to measure premodern units exactly, but much of the time it takes research by subject matter experts laying out careful arguments blabbing half the book to arrive at a good estimate, and 8–24 digits is going to end up in the territory of false precision.

Anyway it's likely that if you cite two online unit converters in your calculations no one will challenge the results. Folly Mox (talk) 08:52, 22 May 2024 (UTC)

The subject of reference is Metrology that Wikipedia divides into sections each of which wastes space blabbing gives encyclopedia-worthy information, not least the essential historical evolution of units that overshadows any anachronistic conversion between ancient and modern units. The Metre is an example of a unit that has been redefined several times since it began in 1791 as Earth's circumference/40,000. Philvoids (talk) 12:59, 22 May 2024 (UTC)

Wikipedia has articles for many units with conversion to metric and American, unit systems like SI or Ancient Egyptian with conversions to metric American and other units of the system the article's about, categories of units of the same type like area units, articles on quantities like area with less obscure units noted along with some cross-system conversions like hectare to or from acre. But not really like that book I saw. It probably didn't have every possible conversion factor but that means room for more units and you could derive any unit pair conversion factor from what's on the page anyway. I'm sure there's a massive multi-volume book covering all of metrology (including detailed care instructions for the one true kilogram and extremely dry statistical error propagationolgy) which I could use to find all the info in that book I saw (maybe requiring me to read the entire book and perform data entry just to get a table of every mentioned length unit and its size in SI ranked by size) but a book like that book I saw could be hundreds of US$ cheaper. Sagittarian Milky Way (talk) 18:54, 22 May 2024 (UTC)

Right in some cases it might be less digits to avoid false precision, a range, ±, ~, c., a value written like 1.26(12), listed as Homeric stadion, Ptolemaic stadion etc or something like that. I don't know if Mecca ever had wine gallon(s) or barrel(s) (Britain had many obsolete local gallons and barrels). I don't know if magnetic fluencivity is real, there's so many jargony science quantities like fluence, abasement or absition (displacement times time), specific volume, jerk (physics) (acceleration squared), impulse (physics), specific impulse (not impulse), permittivity, permissivity, reactance, inductance, capacitance, acoustic resistance, acoustic impedance, electrical impedance, radiation resistance, magnetic flux, magnetic field strength, magnetic susceptibility and magnetic coercivity. I saw one such book long before the SI redefinition and remember international inch 25.4e or similar, U.S. survey inch maybe 9 significant digits/25.4000508 I stopped caring after 0005 to 000508 (my calculator could only fit 00051) so don't remember (1m/39.37 exactly but very or impossibly inconvenient to express exactly in the form cm per inch). Sagittarian Milky Way (talk) 13:18, 22 May 2024 (UTC)

Anyone remember the name of the most recent such book? Sagittarian Milky Way (talk) 13:21, 22 May 2024 (UTC)

Annual personal organizer diaries are usually padded with extra reference information such as maps and some common unit conversions such as degrees Celsius <-> Fahrenheit, metric <-> imperial units, etc. The most recent that will be for year 2025 are probably being printed now. Philvoids (talk) 17:49, 24 May 2024 (UTC)

Did the position "Senior Secretary of Cadres for CPSU" Existed

Hello, I'm researching historical positions within the Communist Party of the Soviet Union (CPSU) because Andrei Kirilenko (politician) page, he held a post called "Senior Secretary of Cadres." However, I haven't been able to find much information about it. Did this position officially exist within the CPSU, and if so, what were its responsibilities? Any guidance or references would be greatly appreciated. Thank you! SleepyJoe42 (talk) 14:37, 22 May 2024 (UTC)

The article on Kirilenko on the Russian Wikipedia mentions many secretarial position in which he served, including serving on the Secretariat of the Central Committee of the CPSU, but nothing resembling this specific designation. The Secretariat oversaw the day-to-day operations of the Party, and specific areas of work were assigned to its members, such as agriculture, but I suspect this was not reflected in a title. Moreover, according to the Russian article on Kirilenko, he oversaw industry, capital construction, transport and communications. The article Секретариат ЦК КПСС states that Kirilenko served as co-Second Secretary next to Mikhail Andreyevich Suslov.  --Lambiam 21:49, 23 May 2024 (UTC)

non-white acting like white

So far, apples means Indigenous peoples acting like white, coconuts means South Asian people acting like white, Oreo cookies means Black people like white and bananas means East and Southeast Asian acting like white, but is there a term for Middle Eastern people, Arabs, Iranians, Afghanis, Central Asians and Turkish peoples and others acting like white people? Donmust90 Donmust90 (talk) 18:11, 22 May 2024 (UTC)

There does not seem to be a specific term for MENA individuals acting or identifying as white. 136.54.106.120 (talk) 23:40, 22 May 2024 (UTC)

Racially speaking, Arabs, Iranians, Afghanis, Central Asians and Turkish are all Caucasians. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:22, 23 May 2024 (UTC)

Some Central Asians look far more similar to Japanese than Caucasus. Sagittarian Milky Way (talk) 04:58, 23 May 2024 (UTC)

Nonetheless, I'm trying to figure out what an Arab "acting like white" would look like. ←Baseball Bugs ^{What's up, Doc?} carrots→ 05:28, 23 May 2024 (UTC)

They are? What do Arabs have to do with the Caucasus mountains? Zanahary (talk) 06:20, 23 May 2024 (UTC)

See Caucasian race, specifically the sentence in the lede that says "In the United States, the root term Caucasian is still in use as a synonym for white or of European, Middle Eastern, or North African ancestry, a usage that has been criticized." I'm sure you're aware of this usage and are just pretending that it doesn't exist. Whether you like it or not, it's still a valid usage. --Viennese Waltz 07:06, 23 May 2024 (UTC)

I'm sure you're aware of this usage and are just pretending that it doesn't exist
Girl Zanahary (talk) 10:15, 23 May 2024 (UTC)

In my travels, I have heard: Oreos for blacks in the U.S. and Bounty bar for blacks in the U.K., Coconuts for Hawaiians, Bananas for Chinese and Japanese, and apple for Native Americans. Googling, I see that coconut is used in Central/South America, many of the Pacific Islands, and Indonesia. There is no reason to assume it wouldn't be used in India as well as India is (I believe) the largest producers of coconuts. I want to make sure it is obvious that all of these terms are offensive. Just because some people say them does not mean that any person should use them, even if it seems funny. I used to think it was OK. I do not get offended. So, I was called a lot of names from silly ones like "round-eye" in China to "oyinbo" in Nigeria. But, I was told that because I laughed, it made the person who said those terms comfortable with saying them to other people who could be offended. So, instead of laughing along, I began asking others to be more polite. 75.136.148.8 (talk) 15:14, 23 May 2024 (UTC)

Do you even know what "Oreo" indicates? ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:20, 23 May 2024 (UTC)

They wrote in the question what it means (Black people acting like white), so why ask?  --Lambiam 07:46, 24 May 2024 (UTC)

I was talking to the IP, not to the OP. Oreo in plain language means "black on the outside, white on the inside", which is a harsh assessment, not intended to be funny. Which leads me to question whether the IP really understands the concept. ←Baseball Bugs ^{What's up, Doc?} carrots→ 18:48, 24 May 2024 (UTC)

(1) You didn't indent, so you appeared to be addressing the OP, not the IP. C'mon, you've been here for 20 years, you know how the indentation convention works.

(2) The IP geolocates to South Carolina, so (assuming no VPN), probably does know what "Oreo" indicates. Hell, I know and I live on a different continent. {The poster formerly known as 87.81.230.195} 94.2.67.173 (talk) 22:12, 24 May 2024 (UTC)

I failed to count correctly, but my indentions were well-intentioned. As for SC, considering who they keep voting for, I wouldn't make any assumptions about their intelligence level. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:35, 24 May 2024 (UTC)

I see nothing in the IP's post that makes me question their understanding of the terms they are using. Making assumptions about someone's political leanings based on nothing more than the location from where they are posting does not suggest an excess of brightness.  --Lambiam 05:28, 25 May 2024 (UTC)

The IP brought up the notion the term "Oreo" somehow being considered "funny". It ain't. And as for being from SC, someone else brought that up too. I question the original premise "non-white acting like white". I don't think that's sufficient. ←Baseball Bugs ^{What's up, Doc?} carrots→ 07:56, 25 May 2024 (UTC)

You did read the question, correct? The question brought up oreo. You did read my response, correct? My response stated that it is offensive even if some people think it is funny. So, now it appears that it is important for you to frame an entire state as stupid and racist to save face. I feel that says a lot more about you than it does me. 75.136.148.8 (talk) 13:16, 27 May 2024 (UTC)

Who have you ever heard use "oreo" as a joke? ←Baseball Bugs ^{What's up, Doc?} carrots→ 18:45, 27 May 2024 (UTC)

Many people. When I was growing up, other kids called me oreo (among many other offensive terms like injun, redskin, and chief) to be mean. They laughed because many kids think being mean to kids who are different is funny. My friends also called me oreo specifically to be funny because they felt it was a way of letting me know that they don't care that my dad was Cherokee instead of black. I am not claiming that it was a full stand-up routine on HBO. I am only stating that they laughed and, in my opinion, people tend to laugh at things that they think are funny. Similarly, if some kids found sticks on the playground, they wanted to play cowboys and Indians, which meant chasing me around the playground while throwing sticks at me and laughing. Because they laughed, I assume they found it funny. I still feel you haven't read my comment above. I feel that I clearly state that even though someone might think it is funny, it isn't. It is offensive. 75.136.148.8 (talk) 19:24, 28 May 2024 (UTC)

You need to identify the which ones were those calling you so, and rationalize for each or each pack a conclusion, otherwise you're just propagating the bad spell ( Voodoo Ch'le ) --Askedonty (talk) 21:04, 28 May 2024 (UTC)

May 26

Graff Aviation

There's an airline called Graff Aviation that I'd like to find out more about, but it seems to have a minimal internet presence. It doesn't have an article on here. There are plenty of photos of its planes, see [4] and [5] for example. But it doesn't seem to have a website and I can't find any information on who owns it or what kind of services it provides. Can anyone provide some more information, please? Thank you, --Viennese Waltz 17:39, 26 May 2024 (UTC)

I can find a Graff Aviation Limited incorporated 1970 and dissolved 2018, and Graff Global Aviaiton Limited, incorporated 2008, still extant. They both appear to be associated with the Graff diamond business. DuncanHill (talk) 18:27, 26 May 2024 (UTC)

From this prospectus it appears they operate aircraft "used by Laurence Graff in his personal capacity". DuncanHill (talk) 18:57, 26 May 2024 (UTC)

Ah, so it's basically his private jet. Makes sense, many thanks. --Viennese Waltz 19:11, 26 May 2024 (UTC)

May 29

Is framing the bag and hanging it on the wall reusing it or recycling?

If you've been to Trader Joe's a couple times, the bag asks you this. 47.153.138.166 (talk) 02:06, 29 May 2024 (UTC)

I don't know how a bag would ask you something. However, per Recycling, what you're describing would be "reuse". Recycling typically involves breaking down the source into component materials. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:45, 29 May 2024 (UTC)

Technically, it would be repurposing. Reusing is simply employing something for its designated purpose multiple times, repurposing is finding a new use for it.--User:Khajidha (talk) (contributions) 11:27, 29 May 2024 (UTC)

Assuming the framed bag is "art", it seems like it would be upcycling. Matt Deres (talk) 17:42, 30 May 2024 (UTC)

Naively-cascaded biquad bandpasses vs Butterworth bandpass filters

What's the point of using Butterworth filter design for IIR filter bank spectrum analyzer if simply stacking biquads (w/ exact same properties for each stages) many times (which is what I've implemented in "Analog-style analyzer" mode on this filterbank-based audio spectrum project) is good enough? And what are advantages and disadvantages of naively cascading biquads over using "real" Butterworth bandpass filters for filter bank-based audio spectrum analyzers? And BTW, what is a name for IIR filter design where steeper rolloff is achieved simply by stacking the exact same filter over and over? 114.5.214.236 (talk) 05:50, 29 May 2024 (UTC)

Well a Butterworth filter is optimum with spectrum flatness. A design engineer may want to get the "best" out of something, or may just want to do it as cheap or simple as possible. Other consideration such as whether the components are available or stable, or delay is too much can also become relevant. If it's implemented in software then other aspects may come in, such as intellectual property, but component values will be irrelevant. Graeme Bartlett (talk) 22:30, 29 May 2024 (UTC)

@Graeme Bartlett True, but what I'm concerned about is more of choice of filter types (e.g. Butterworth, Bessel, and even Linkwitz-Riley) for filter bank-based spectral analysis like 1/3rd octave band spectrum analyzer. BTW, I go for the "cheaper" or more precisely, simpler route, which is simply stacking the bandpass filters many times because I'm not an audio engineer (at least a good one) and the result is just good enough anyway if you don't care about details of the bandpass filter's properties. 114.5.208.150 (talk) 23:44, 29 May 2024 (UTC)

Stacking will not optimise the edge roll-off and may have complicated phase shifting. But for your application it doesn't matter. So simpl;icity and cheapness are more important. Perhaps there is an IC that can do the job. If you can find it, it could be very cheap and simple. Graeme Bartlett (talk) 00:55, 30 May 2024 (UTC)

@Graeme Bartlett and Philvoids: Yeah (considering stacking/cascading two time-domain filters is equivalent of squaring its frequency response) but obviously, since this question is related to this relevant CodePen project, I'm talking about this filter bank design implemented in software (which is digital obviously) strictly speaking. 114.5.211.132 (talk) 04:06, 30 May 2024 (UTC)

Tango (soccer ball)

Hello. If I remember correctly, for a certain period, the Tango was also the official ball of the old European Cup finals (the current Champions League). Since when and for how many years? Thank you very much. 93.148.11.229 (talk) 19:52, 29 May 2024 (UTC)

See Adidas Tango 41.23.55.195 (talk) 05:34, 30 May 2024 (UTC)

May 30

Red-eye Flight Movies

Long ago, before the invention of In-flight entertainment, did the airlines show projected movies on their red-eye flights? I think it's tolerable because people were given masks and earphones. -- Toytoy (talk) 01:45, 30 May 2024 (UTC)

On December 5, 1983, I took an American Airlines red-eye from Los Angeles to Chicago, and they showed the movie Staying Alive. Sorry, no WP:RS to cite. --142.112.143.8 (talk) 02:34, 30 May 2024 (UTC)

@Toytoy: How long ago? The article you link says in-flight entertainment began in 1936. It also says After World War II, food and drink services were offered, and movies were projected onto big screens viewable by all passengers on long flights. You can read more about in-flight movies in the History section of that article. RudolfRed (talk) 03:21, 30 May 2024 (UTC)

• I suggest the original poster was talking about seat-back screens with individual entertainment selections. --142.112.143.8 (talk) 05:25, 30 May 2024 (UTC)

From my memory, the overnight flight would stop showing movies at some point in the night, and turn lights down low. Graeme Bartlett (talk) 04:31, 30 May 2024 (UTC)

Before the invention of seatback LCD monitor, technically, you may still watch movies without disturbing others at night, as long as people are wearing sleep masks and earphones. I just don't know if they DID SHOW MOVIES alll night long on a red-eye flight. If not, people who don't like to sleep may find it difficult to pass the time. -- Toytoy (talk) 11:59, 30 May 2024 (UTC)

In the 1980s, movies were projected onto large pop-down screens but without sound (you had to use earphones to listen to it). So it wasn't too disturbing for passengers who wanted to sleep or read or whatever. As Graeme Bartlett mentions above, only one movie would typically be shown on an overnight flight, after which the cabin lights were dimmed until breakfast was served before landing. This is all from personal recollection Xuxl (talk) 15:35, 30 May 2024 (UTC)

Your recollection is correct. Viriditas (talk) 21:49, 1 June 2024 (UTC)

The earphones were made from plastic tubing and plugged into a speaker in the armrest. You had to pay for the earphones and then give them back at the end of the flight, presumably so that you didn't get a free listen on the way back. I watched a whole James Bond film (maybe The Living Daylights) without the sound on the way to Australia (it still made sense - kind of). There was only one film in the 23 hour flight. Alansplodge (talk) 16:48, 3 June 2024 (UTC)

Particular curiosity 1992 European Cup Final

It is a tradition that on the ‘ears’ of the trophy, ribbons in the social colours of the winning team are wrapped. In the case of Sampdoria's success at Wembley in 1992, what colour ribbons would they have been? One has to take into account the fact that Samp, that evening, was playing in the visiting team's uniform. Is it plausible to think of a pair of white and blue ribbons, like the uniform that night? Thank you very much. 93.148.11.229 (talk) 22:27, 30 May 2024 (UTC)

One can hope to move this out of the area of speculation by looking at earlier cases in which the winning team played in away colours. But how old is this tradition? For the 1991 European Cup final, photographs show the winning team hold up a cup with bare ears.^[6] Also for the 1990 European Cup final, the captain of the winning team is seen to hold up a trophy with unadorned ears.^[7]  --Lambiam 05:43, 31 May 2024 (UTC)

Websearching images for "1992 European Cup Final trophy" finds images of the winning team Barcelona with the trophy adorned with ribbons of their colours (blue and red, although 1992 European Cup final misleadingly shows a graphic of a mostly orange strip), so certainly had Sampdoria won it would have borne their colours instead.

Whether it would have been their (then) home or (then) away colours that they actually played in remains unresolved, but I note that, according to their article UC Sampdoria (is it correct?), their current home colours are (mostly) blue shirt and white shorts, and their away strip is white shirt and blue shorts. If that was also the case in 1992 then the ribbons would have been white and blue regardless.

Perhaps the OP knows, and will kindly tell us, what Sampdoria's home strip was in 1992? {The poster formerly known as 87.81.230.195} 94.2.67.173 (talk) 12:42, 31 May 2024 (UTC)

The colours do not change, so the substance does not change. Sampdoria's home uniform consisted of a blue shirt and white shorts. At Wemblely, it was simply the other way around, the colours of the ribbons would not change. Thanks a lot guys.

May 31

I saw those words today and dont know the difference. What is the difference of a curvy, voluptuous, thick and athletic body shape?

I saw those words today and dont know the difference. What is the difference of a curvy, voluptuous, thick and athletic body shape? Give me picture examples to make simple as google PS: If one of those ( curvy, voluptuous, thick ) is mistaken with fat, show a fat person to show the difference.177.63.95.122 (talk) 21:23, 31 May 2024 (UTC)

The words "curvy" and "voluptuous" imply that the individual is female ("curvaceous" is also used). To be fair to the OP, his native tongue is most likely Portuguese, where the corresponding words may have a wider meaning. Example: Boletim do Instituto Menezes Bragança [8] (on page 148):

...Índia conferiram a sua obra "originalidade e vigor que o aproximam ora do lirismo místico de Tagore, ora do satanismo voluptuoso de Beaudelaire".

...India conferred on his work "originality and vigour that approximate it now to the mystical lyricism of Tagore, now to the voluptuous Satanism of Beaudelaire".

OP, all you have to do is open up a generative AI website. It will create those images for you to look at. I could be wrong, but in the US, curvy, voluptuous, and thick are generally used as synonyms, even though each can have their own separate definitions and differences. I remember reading that there's also a certain amount of cultural overlay. For example, "curvy" is considered body positive. "Voluptuous" implies a somewhat larger figure, but having just looked into it a bit closer, I see it is indeed used in the same way as curvy. Athletic generally entails thin and slightly muscular or defined, with a much smaller top and bottom. As for the term "fat", I think the term you're looking for is "obese". I think what you are really getting it is, can a curvy, voluptuous, and thick woman also be labeled obese? And the answer is most obviously, yes. More interestingly is to examine similar terms for men, which hasn't been done enough in recent years except for the somewhat newer subject of the dad bod. Viriditas (talk) 21:41, 1 June 2024 (UTC)

"Thick" is a slightly nicer way of saying "fat". ←Baseball Bugs ^{What's up, Doc?} carrots→ 06:26, 2 June 2024 (UTC)

Not exactly. Christina Hendricks might be described as "thick" (or "curvy" or "voluptuous" or "zaftig"), but I don't think anyone would call her "fat". --User:Khajidha (talk) (contributions) 12:02, 3 June 2024 (UTC)

Miscellaneous world records

What's the world record for...

1. ...the largest peaceful gathering?
2. ...the smallest and largest food?
3. ...the longest amount of time spent on the FBI's Most Wanted List?
4. ...the most common type of restaurant (as in the cuisine they serve)?
5. ...the most subscribers achieved on YouTube within a single week?

47.153.138.166 (talk) 22:53, 31 May 2024 (UTC)

For item 1, you can probably rule out soccer matches. For item 2, roast camel is pretty good sized. Meanwhile, bacteriophage viruses eat bacteria, which are pretty small. ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:57, 1 June 2024 (UTC)

Further, cursory Internet searches reveal 3) 32 years, for Victor Manuel Gerena and 5) supposedly around 10 million, for Hamster Kombat (the figure is corroborated here, but there isn't an easy way to definitively verify that this is indeed the highest ever achieved). I don't know that there's a meaningful answer to question 4 -- it depends on how you define "type"/"cuisine" and on what scale. There are apparently over twice as many restaurants in China than in any other country, and Chinese restaurants are fairly popular in India (more so than vice-versa), so if you consider "Chinese" to be a single "type" of restaurant that's probably a good guess. (fugues) (talk) 05:15, 1 June 2024 (UTC)

For item 2, check whale blubber, though it doesn't state the species involved. -- Verbarson  ^talk_edits 16:28, 1 June 2024 (UTC)

For 1, see List of largest peaceful gatherings. --Viennese Waltz 07:10, 1 June 2024 (UTC)