So why aren't we trying this? Let's assume problem is repeated UTF-8 encodings (which happens when UTF-8-encoded data is interpreted in an eight-byte code page and written again as UTF-8). The worst case appears to be code point 150, which is the en-dash in CP-1252. It is this character: – The sequence of lengths of files when this happens, starting from this single character, is: 1, 3, 8, 18, 39, 85, 189, 422, 942, 2099, 3806, ... This does not appear to be an OEIS sequence; we might consider making it one . . . The growth rate appears to be 2.226101... which we can call Lunnon's constant. These values can be calculated with a small 22x22 matrix representing the different character values that are encountered in this repeated expansion. Surprisingly, we never encounter any of the illegal CP-1252 codes which might abort the process. -tom On Wed, Jul 25, 2018 at 6:39 PM Fred Lunnon <fred.lunnon@gmail.com> wrote:
Further observation suggests that this particular `worm' is growing only linearly rather than exponentially. However, the potential for exponential growth --- eg. where some mail-server replaces an unrecognised character code by two copies of the same --- remains when users attempt to employ rich codes, and might quickly bring down large parts of the list network, particularly if the bug lurks on the central list server.
[Two characters may not be a long string by itself; but after (say) 30 replies, a billion characters concealed beneath your top posting becomes bad news!]
WFL
On 7/25/18, Fred Lunnon <fred.lunnon@gmail.com> wrote:
WARNING: at the start of Simon Plouffe's message is lurking what appears to be the seed of an exponential textual worm. On most systems this specimen should enter suspended animation when the thread does; however in the past I have encountered something similar: an apparently innocuous string duplicated every time the mailer saves its current state, until the file attains catastrophic size.
WFL
On 7/25/18, hbaker1 <hbaker1@pipeline.com> wrote:
I like your idea of a "smart string"!
The three lower strings of a violin are typically "wound" with metal, while the highest string ("E") is typically a single wire.
It would be easy to incorporate a fiber optic fiber into the core of a string, and utilize this to sense various aspects of the string, and also provide a communications medium to transmit this information to a controller at either the peg or the "tail" attachments.
As long as you have control over the tension of the string, one could change this tension on a second-by-second basis, or even within a cycle of the vibration of the string itself.
Current rock guitars have a lever to change the tension of *all* of the strings simultaneously, but a more sophisticated system would provide individualized control of each string.
If you're ever in L.A., be sure to visit the top floor of the Nethercutt auto museum in Sylmar; it has the most amazing collection of mechanical musical instruments. (It's also a great collection of interesting cars, unlike the Peterson museum which is a collection of so-so cars previously owned by interesting people.)
http://www.nethercuttcollection.org/
-----Original Message-----
From: Hilarie Orman <ho@alum.mit.edu> Sent: Jul 24, 2018 11:10 PM To: math-fun@mailman.xmission.com Subject: Re: [math-fun] 3D printers & musical instruments
Interesting idea. It is necessary for the adjustment mechanism to be fairly small and lightweight. How about a "smart string"?
The sensing of the tone has to be done some distance from the instrument, so I foresee a phone app for that. Bluetooth comms to the string molecules. On command from the conductor (the orchestra leader, not the electrical wiring). Imagine tuning the entire string section in one second!
Hilarie
Harmoniously, on Tue, 24 Jul 2018 at 20:51:53 -0700 (GMT-07:00) hbaker1 intoned:
It also occurred to me that one could build a "smart" tuning "peg" for stringed instruments that would measure the tuning of that particular string and adjust itself to always be in proper tune.
While tuning for 4 strings isn't that much work, keeping a piano constantly in tune might be a significant advantage.
I don't know the going rate for piano tuning, but it isn't cheap, but it is amazingly difficult to schedule if you've got an upcoming concert.
-----Original Message-----
From: Hilarie Orman <ho@alum.mit.edu> Sent: Jul 24, 2018 4:30 PM To: math-fun@mailman.xmission.com Subject: Re: [math-fun] 3D printers & musical instruments
There are 3D printed violins, but they are indeed too heavy. There are electric violins with lovely 3D printed pieces, and there is some hope for customizing such instruments to the anatomy of the artist, and that might be worth the cost of the instrument (for jazz or country musicians).
Let me note (a 441 A) in passing that the mystique of a Strad is largely due to marketing hype from a couple of hundred years ago. Yes, they are generally very good instruments, but they have been modified from their original construction to meet modern demands (and to repair them from sometimes awful injuries!). Newly minted instruments from a master luthier can sound equally good.
In considering design alternatives based on "aesthetics", it is important to consider the artist as part of that. The instrument must respond to control by the artist, it must be predictable, it must have a range of dimensions and an intuitive interface with tactile feedback. I think that this might be achieved with nanomaterials and active control. I've no idea how to do this, nor if it amounts to "reinvent wood."
Hilarie
On Mon, 16 Jul 2018 at 09:22:19 -0400 Richard Howard contended:
> Airplanes don't have feathers. > Given 3D printing and full acoustic simulation, why would you make a > "violin". > That design came from another set of constraints (properties of wood, > available configuration tools, etc.). > New instrument would be based on other constraints, which could use > principles of aesthetics.
> --R
> On Mon, Jul 16, 2018 at 3:34 AM, Simon Plouffe <simon.plouffe@gmail.com> wrote:
> > ​Hello, > > > > they made one experiment once to make a violin > > from scratch using a design based on acoustic and > > physics only, they actually ​succeeded in making one, > > the sound was good, even comparable to a Stradivarius, > > it worked, the only thing is that the violin was ugly. > > The article was on Scientific American a long time ago. > > > > I think that 3D printing is about the same, we probably > > could print a violin, it could also sound pretty good, > > but it won't replace the look and feel and lightness of > > a wooden real model. Does anybody ever saw the film > > : The Red Violin ? > > > > Best regards, > > Simon Plouffe
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