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whiw

51 karma · joined February 5, 2016

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whiw··on Show HN: OM Core – multidimensional models without spreadsheet cell formulas
I've read the docs but I haven't tried it yet. I like the idea of storing n-dimensional data in an n-dimensional table, and I like the separation between the data ('cube') and the views and rules. I like that the rules operate on slices of the data rather than individual cells.

This occupies the space between traditional spreadsheets (simple UI but limited to 2-d) python (multi-dimensional data, and python or tensors (multi-dimensional data, but coding required).

I feel that the current data input is a bit cumbersome. There's a lot to type to enter just one cell value, and multi-dimensional tables contain a lot of cells. A more succinct alternative for data entry could be something like python/numpy multi-dimensional tables: [[[a, b, c], [d, e, f]], [[g, h, i], [j, k, l]]].

Data entry from a view grid (to a 2-d slice of the 'cube') would be more familiar, like a spreadsheet.

A data import feature (from csv, etc) would be useful too.

'Cube' has 3d connotations: 'ngrid' or 'ndata' could be less confusing.

I didn't see any functions like sum or product (or most other spreadsheet functions) to operate on data slices. I'm guessing that this is still proof of concept at the moment.

I do hope this goes further.

whiw··on Where to Find the Colors Your Screen Can't Show You
If we had a display with n (n>3) pixel colours, say (red, green, cyan, blue) for example, we could display more of the colour space. Shopping list: 4 colour channel display, 4 channel GPU, 4 channel software. Why isn't this a thing already?
whiw··on Cheap DIY solar fence design
I'd be concerned about clay heave (where clay shrinks/expands depending on moisture content, which likely varies over the year). If the posts at each end of a panel move out of plane there will be a twisting moment on the panel, and glass doesn't like being bent.
whiw··on Lead pigment in turmeric is the culprit in a global poisoning mystery (2024)
I meant lead carbonate, not lead oxide.
whiw··on Lead pigment in turmeric is the culprit in a global poisoning mystery (2024)
I am not a chemist, so take this with a pinch of salt: wouldn't lead chromate + sodium bicarbonate make lead carbonate, a white precipitate? Sodium bicarbonate is likely in your kitchen cupboard already.
whiw··on Kissing moons may explain why Earth's moon is so large
Presumably from tidal forces, from the differential of the gravity field in the presence of nearby massive objects (like the sun, or jupiter).
whiw··on Fish-delousing underwater laser (2018) [video]
That seems a somewhat callous disregard for the fish, blinded and swimming around with itchy eyes from burned out retina.
whiw··on Fish-delousing underwater laser (2018) [video]
If the laser is powerfull enough to kill sea-lice then how does it avoid blinding the fish or giving them retina burn?
whiw··on Moving to a RTOS on the RP2040
> Printf isn't re-entrant, and they are calling it from multiple threads.

This! Simple schedulers generally only allow system calls (such as printf) from the main thread. If you really want to 'print' from a child thread then send a message to the main thread, asking that it prints the message contents on on behalf of the child thread.

whiw··on My new PSU burns out – I fix it, and torture it by cracking water
The transformer secondary was maxing out at 4A, 36V. The primary current will be much lower, probably about (40V/240V)*4A, ie about 0.67A.
whiw··on Roll-Invert-Unroll: An easier way to replace a duvet cover
Paisley pattern. Oh, somebody beat me to it.
whiw··on The Ultimate Docker Cheat Sheet
This looks useful, I wish I'd found it a month ago. One suggestion: could we have a more printer-friendly version (ie, without large patches of colour and without large patches of black)?
whiw··on Medieval staircases were not built going clockwise for the defender's advantage
I imagine that it would be more difficult to gain entry to an upper floor (at the top of a narrow staircase so single-file attackers) and a sturdy door with a couple of guards outside, than it would be to gain entry to rooms on the same level. Perhaps the women were tucked away on the upper floors, in relative safety.
whiw··on JWST spots giant black holes all over the early universe
> Galactic spectra, which JWST started to send back in earnest at the end of last year, are useful for two reasons.

> First, they let astronomers nail down the galaxy’s age. The infrared light JWST collects is reddened, or redshifted, meaning that as it traverses the cosmos, its wavelengths are stretched by the expansion of space. The extent of that redshift lets astronomers determine a galaxy’s distance, and therefore when it originally emitted its light.

Won't a photon climbing out of a huge gravity well have a huge redshift, thus confounding estimates of distance from us and estimated age?

whiw··on The FBI now recommends using an ad blocker when searching the web
> (I came up with this one): use a little firewall rule that prevents any IDN from resolving. That's a one line UDP rule and it stops cold dead any IDN homograph attack. Basically searching any UDP packet for the "xn--" string.

I couldn't see how to do this in Windows Firewall. Which OS/firewall/rule are you using?

whiw··on ThreeUK blocks access to encrypted provider Tutanota due to 'age restriction'
If you are a light user (in the UK) then 1p Mobile is excellent value. I've no links with them (apart from being a happy customer). They use the EE network, so coverage is good. Costs are 1p/minute calls, 1p/text message, and 1p/MB data, and you must top up by at least £10 every 120 days. Unused credits rollover to the next period. They have also introduced a newer scheme: £36 per year for unlimited talk and texts, and up to 250MB data/month. Again, I think that unused credit rolls over (i haven't used this option, so check the details).
whiw··on U.S. bans equipment from Huawei and ZTE, citing national security concerns
google VLAN hopping
whiw··on DIY Tool Storage Ideas (2017)
The magnetic drill bit rack might cause the swarf to cling to the drill bits.

I use plastic picture/poster hanging grips to cover saw blades, and lengths of 4" plastic waste pipe to store dowel and metal rod.

whiw··on Parmigiano Reggiano makers embedding tiny trackers in rind to fight cheese fraud
Presumably the grocer or end user will end up with a pile of rind containing the embedded tagging chips. Fraudsters could simply gather/buy the waste rind plus trackers to embed them in their own fake products. Unless there is a robust disposal process (sending them back to the cheese producer), the genuine trackers will just end up 'authenticating' fake products.
whiw··on LG’s new 16:18 monitor
18:16 is 1.125:1, but 4:3 is 1.33:1
whiw··on Ask HN: Advice about aging parents
I had considered it briefly. Unless it is for a tiny number of residents (2?) then I think that the CQC will want to come and do inspections. It would be necessary to assume that the residents are, or will soon become, highly dependent (needing 24/7 care).

In the UK I believe that at least two qualified nurses are required on site at all times, plus carers sufficient to care for the needs of the residents. Assuming 8 hour shifts you will need to triple that number. Multiply by a further 7/5 to account for weekends. Multiply by a further 52/46 for holidays, sickness and training. Add some for receptionist, accountant, handy man, cook(s), cleaners, manager(s).

That is quite an overhead just for wages. Add to that any mortgage for the property, heating, rates, repairs, office equipment, etc, etc.

With rooms becoming vacant and requiring redecoration between residents, there will not be 100% occupancy. The cost to break even is substantial. Even commercial care homes go out of business quite regularly. I can understand why residential care is so expensive.

Having been a frequent visitor to care homes I know that many / most of the residents most certainly do not wish to be there, and want to be back in their own home. Almost all of the staff do a fantastic job, doing unpleasant tasks without complaint, and doing their utmost to create a friendly and inclusive atmosphere.

The existing care system is very expensive for users. A more informal arrangement with less bureaucracy providing care at home would be useful.

whiw··on Testing Phone-Sized Faraday Bags
> Faraday cages are non-directional.

Per-se, yes, agreed, but I was wondering whether the transmitter and receiver antenna couple into the surrounding screen differently. The degree of coupling may de-tune them differently. If so then the setup which most accurately represents the intended use would be with the receiver inside the screen.

whiw··on Understanding Indirect Time-of-Flight Depth Sensing
If the other emitter/sensor pairs are uncorrelated with our own, and if we integrate over enough transmit/receive cycles, then the other pairs will contribute approximately equally to both of our own two sensor phase detectors. The method descibed here uses the difference between the sensor phase detectors, so any competing interference should cancel out. It will (just) raise the background noise floor a bit.
whiw··on Social networks neither ‘social’ nor ‘networks’ – what should we call them?
Clique Clusters
whiw··on Latest EmDrive tests at Dresden University shows it does not develop any thrust
The knowledge that we have gained from this experiment is that the experimental data disagrees with the theoretical justificiation for the idea. That isn't the same as proving that the theory is wrong, even if that seems the more likely explanation. To be sure that the theory is wrong we would need an analysis of why that is the case and what were the false assumptions and faulty reasoning behind it. Any volounteers?
whiw··on Raspberry Pi for Kill Mosquitoes by Laser
I'm not arguing that mosquitos shouldn't be killed. I'm arguing that one should not wantantly choose a painful way of removing them. Alternatives which could be better include natural predators, quickly squashing them, soapy water, soap film on stagnant water to kill off the larvae (but not where other aquatic life may be harmed). Just avoid the mean ways.
whiw··on Raspberry Pi for Kill Mosquitoes by Laser
If you do have to kill something then at least do it humanely. Burning them to death is pretty horrible, so is zapping them with a high voltage shock.
whiw··on Google to stop selling ads based on your specific web browsing
"Customer Off The Shelf" and "Radar Cross Section"
whiw··on Show HN: Are you playing your violin (viola, guitar, etc.) in tune?
I'm not sure it is better, unless you can do autocorrelation in hardware without using an fft. This option is unavailable on standard PCs.

If done in software then a simple implementation of autocorrelation is O(n^2). An efficient implemementation is O(n.log(n)) (it uses two ffts).

whiw··on Show HN: Are you playing your violin (viola, guitar, etc.) in tune?
I've just noticed an error in the above: 330Hz should read 1312Hz.

The remaining figures still look ok though.

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