iiinova — where your digital self keeps evolving

katch wreck @katchwreck.mastodon.social.ap.brid.gy · 29/09/2026

i have some more thoughts to add to this thread but not tonight... for now here's another cool picture of my dad from 1945 `Military honors, including Order of the Red Star`

Boris Korenblum (1945) after WWII victory, with Military honors, including Order of the Red Star

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 29/09/2026

thus, after some thought, i believe that the goal of science should not be to reduce nature to simple mathematical laws, but to promote the use of the richest language, namely mathematics, that we have to describe nature in a way that can serve humanity […] [Original post on mastodon.social]

Boris Korenblum (my dad) teaching at the Kiev Institute of Civil Engineering in 1965

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 06/09/2026

OMG i played with this thing for WEEKS at a time when i was a kid! haha anyone else remember this guy?? cc @aaronmeyers

Umber Hulk action figure (Advanced Dungeons and Dragons), circa 1985

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 06/09/2026

here's another cool set of outputs from the same dataset, using a different set of hyperparameters for defining the region of interest... now that i have the training system dialed in, i can start doing some cross-validation testing to a establish a statistically-rigorous performance estimate

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 05/09/2026

this isosurface overlay was generated by comparing per-subject waveform shape feature distributions from a single EEG channel that came from a public dataset with 88 subjects labeled as having an Alzheimer's dementia diagnosis, frontotemporal dementia […] [Original post on mastodon.social]

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 19/08/2026

same one again but with a different camera angle and a darker shade of background gray

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 19/08/2026

here's a cleaned up version, with axis labels suppressed to reduce clutter

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 18/08/2026

i had originally written off these 3D isosurface overlays as being too much of a pain to get dialed in, but after some tinkering i think they're growing on me! :) (see alt text for details)

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 19/07/2026

fun with data visualizations :) could you tell them apart without the colors?

two-panel filled contour plot, with color indicating group label, showing adjoined densities estimated over two-dimensional a waveform shape-feature space

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 18/07/2026

i don't know what i'm doing but i generated this gigantic PNG file using a fun program called Apophysis #art #generativeArt #fractalFlame

$"fractal flame" (whatever that means) as generated by me using Apophysis (whatever that means)$

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 04/06/2026

@bourgwick "the city's known as Psychedelphia".. that's a new one for me :) i like this guy! Halloween idea?

screengrab from black & white BBC video documenting the SF club scene in 1966, featuring a live performance of Phil Lesh's tune called "Mindbender"

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 04/05/2026

here's the harmony chart for those that want to know all the gory details :)

lead sheet for "melodic logic", an 8 bar etude illustrating the use of the melodic minor scale in the context of a ii-V7-i progression based on the Dorian mode

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 01/04/2026

it didn't quite wrap but the lavash withstood the strain :)

salmon and veggie wrap on spinach lavash

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 28/03/2026

corresponding training & test AUC-ROCs after reducing per-shapetype 1D Bayes classifier predictions to per-channel predictions (reduction via a logical heuristic). each electrode position corresponds to a color code. red & green are contralateral to the […] [Original post on mastodon.social]

grouped bar chart showing AUC-ROC vs. electrode position (training & holdout test =)

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 26/03/2026

according to facebook, this was a sandwich i made 17 years ago... thanks, i guess? :-P

a seitan sandwich made 17 years ago, on this day

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 25/03/2026

while i enjoy algorithm development, data analysis, and programming, i am really glad that this study is almost over! so exciting to not feel like i'm chained to my desk for months at a time :) we currently compute two shape-feature distributions per […] [Original post on mastodon.social]

montage of heatmap overlays, each panel shows one waveform shape feature distribution comparison, revealing areas where probability is relatively enriched (dark blue) or depleted (cyan) in the post-traumatic epilepsy group (both groups received traumatic brain injuries, but some recovered without developing epilepsy). red outlines show top-ranked ROI, obtained via the nonparametric test i developed recently. electrodes are color-coded by position: red & green are contralateral, yellow & black are ipsiperilesional. top row: shapetype 1, bottom row: shapetype 2

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 25/03/2026

truth be told, we use two correlated but not identical "shape types" for each waveform we characterize. and, it turns out the other shapetype on the green also yielded a similar, but not identical, ROI! it was by combining these two ROIs, which were the top […] [Original post on mastodon.social]

similar green-channel ROI from shapetype 2. notice that it is not quite a mirror image of the ROI from shapetype 1.

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 24/03/2026

... imagine my surprise when i saw almost exactly the same ROI appear from yesterday's results using an automated system restricted to the green channel! guess who's baaaack :) but now i can show you a better plot, overlaid onto the heatmap used by the […] [Original post on mastodon.social]

for this analysis, samples were in the form of one 2D distribution per subject. heatmap overlay of ROI from the green electrode with top-ranked training performance, and also high holdout test performance for predicting PTE in TBI, as identified using a newly-developed nonparametric formula. by varying the parameters of this test, different heatmaps can be generated (log-odds units), allowing a variety of ROIs to be defined from a single training dataset (each sample contributes one 2D distribution to one of two classes). by optimizing the test parameters, this ROI was automatically identified and shown to achieve good performance for predicting PTE risk during epileptogenesis (first week after TBI).

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 21/03/2026

in essence, this formula allows us to infer topologic relations from topographic ones

a region of interest (ROI) identified between two sets of distributions: cyan => TBI+, PTE-, dark blue => TBI+, PTE-

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 20/03/2026

i'm still fine-tuning the design of the test. there are a lot of adjustment you can make, but in the interest of minimizing parameter number, four will hopefully be enough! this is the most specific ROI we've found in this dataset.

image showing a comparison between two sets of 2D shape-feature probability distributions, with a red contour indicating the region of interest (ROI)

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 18/03/2026

each subject contributes one 2D distribution to the set, so intra-class variability between proximal points in 2D can be large. one of the cool things about this nonparametric ROI test is that it has built-in robustness parameters. this means that it is […] [Original post on mastodon.social]

large-area region of interest (ROI) containing significant & consistent differences in probability between positive (dark blue) & negative (cyan) classes

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 16/03/2026

here's a really cool looking region of interest (ROI). this one is big! the formula i came up with works in any dimension. of course, explicit density estimation rapidly breaks down with the curse of dimensionality. so, we probably can't extend this to […] [Original post on mastodon.social]

large area ROI showing significant shift in probability density between positive (dark blue) and negative (cyan) classes

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 15/03/2026

Still working on the writeup but I did make a slightly better plot :) the problem we had was that our data has the form of probability distribution functions over a 2D feature space from two different classes, and they have a lot of variation from subject to […] [Original post on mastodon.social]

comparing two sets of probability distributions over a 2D feature space using a heatmap with units of log10 odds between classes using an optimized comparison threshold. dark blue indicates enrichment of probability in the positive class. the smooth, contiguous, closed boundary of the nonparametric ROI detected having the best empirical performance (using the labeled training data for performance ranking) is drawn as an overlay.

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 15/02/2026

so that was cute but i think this is a little more legit :) only $30! plus there's more room

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 07/02/2026

turns out you can quickly make a functional pedalboard with cardboard, velcro, and mounting tape 😋

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 27/01/2026

here's a preview of what i've found using this new technique... happily, this is grant work, so i will be able to publish more on these results soon!

plot showing a non-parametrically defined 2D region of an abstract feature space

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 17/01/2026

i clipped the input when i beatboxed this kick hit! cool shape though

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 16/01/2026

here's what it looks like with a constant red of 0.5

colormap using red=0.5, green from 0 to 1

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 26/12/2025

here's a cute melody that i literally dreamed up the other day and then fleshed out based on what i remembered from my dream :) happy holidays! #happyHolidays #merryChristmas #melody #dream #music

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 23/12/2025

i do plan to abandon windows soon, but i have not fully made that switch, and i just want to point out another truly annoying feature: if you hit F1 by accident, anywhere, it opens the MS Edge browser, which cannot be un-installed. and, when you close the […] [Original post on mastodon.social]

screenshot of Windows 10 task manager with 5 active Edge processes running

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 13/12/2025

it's more than a doodle... it's a squiggle! :) #squiggle

doodle with eyes on the stuff that looks like a face

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 09/12/2025

this is not one of the better-known Bob Marley songs, but I like it... so i made a simple harmony chart for it :)

chords, lyrics, & arrangement for the Bob Marley song entitled "I Know A Place"

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 05/12/2025

whoever digitized this tape included a pic of the cassette :) ahh memories

image of side A of Black Uhuru - Tear It Up - Live [Cassette UK 1982]

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 16/11/2025

check this puppy out! only about $40 for the PCIe RAID card, and only about $30 for each of the NVMe SSDs... total cost was about $180 including shipping & tax! going to set it in striping mode (RAID 0) in an attempt to speed up my data I/O rates... a […] [Original post on mastodon.social]

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 12/11/2025

[spoiler alert] but notice that a minor iiø7-V7 progression traces out a dim7 chord. so, it kind of makes sense that you should be able to find pairs of minor ii-V chords inside this set of 4 half-dim7 and 4 dom7 chords! and, when you look hard enough, that is exactly what you find :)

four minor ii-V progressions, each involving two chords that are related to the same diminished seventh chord (including inversions, by symmetry)

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 12/11/2025

[spoiler alert] thanks for the activity on this post :) here's how the idea began: as is commonly known, you can easily derive a dominant seventh chord from a diminished seventh chord by flatting the root. similarly, you can derive a half-diminished chord […] [Original post on mastodon.social]

four dominant seventh and four half-diminshed seventh chords, all related to a single diminished seventh chord by a single semitone alteration

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katch wreck @katchwreck.mastodon.social.ap.brid.gy · 11/11/2025

this little ditty started as an exercise or etude involving the idea of a "tetrad" of ii-V progressions, all related to a single chord... maybe it will evolve into a real song! you can also think of it as a musical puzzle: what is the "hidden chord"? :) […] [Original post on mastodon.social]

a chord progression involving a "tetrad" arrangement of ii-V chords, all of which are related to a single "hidden" chord (not played)

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