derstander

I'm going to step back to a meta level and make a couple points:

- Several times in the context of this discussion you've made negative assumptions about someone or their motives replying to you (e.g. "I wanted to give a seriously reply, but clearly there is no point" and "What a stunning revelation, genuinely brilliant insight from you"); I don't think this fosters good discussion (and I also don't think it's particularly good for mental health)

- You seem particularly aggrieved by someone not automatically assuming you know something. Yes, we all understand now that you know the Mesopotamians predated the Greeks with regard to the mathematical notions we're discussing here. But you know what? There's nothing wrong with NOT knowing. And some people reading the discussion might not have known.

Now back to the main topic at hand.

> Even if they did and even if the Greeks were extremely influenced by them, their concept of a geometrical zero was still radically different to the Mesopotamians notion, so it is totally irrelevant who was first

Now I finally feel as though I understand the main thrust of your argument. Let me restate your hypothesis to see if I've got it: even though the Babylonians had the concept of zero, it was sufficiently lacking compared to the Greek concept as to be incomparable; the Greeks fundamentally independently invented the concept of a zero more mathematically powerful than the Babylonians rather than took the existing Babylonian concept of nought and developed it further. Is that right?

> No. You are still ignoring that the mathematics of the Greeks and the mathematics of the Mesopotamians were radically different.

This doesn't matter. We're talking about 0. Whether mathematics are conceptualized as a tool or an academic discipline in its own rite wasn't the thrust of the article. It wasn't even part of your original post.

> Did you even read my original post?

It might surprise you, but yes -- yes, I did!

> My position is that a linear history of the concept of 0, which spreads from India to Mesopotamia to Greece is nonsense. That the Mesopotamians did some mathematics long before the Greeks did is irrelevant to my argument. It totally does not matter. What makes it even more ridiculous is that my OP obviously assumes that the Mesopotamians had mathematics before the Greeks, so pointing it out as some "gotcha" is just really stupid.

This is a better statement of your position than you originally posted, when you said "I am very unconvinced by this "history of zero". Definitely the Greek geometers were aware of that concept, they just expressed it geometrically not numerically." Here's why I think your initial statement is a weak argument for your refutation of a linear history of the concept of zero: Babylonian mathematics temporally happened first and the general opinion (when I was in school, at least) was that Babylonian mathematics likely influenced Greek mathematics. That's why I think this is a weak argument to argue against the linear history concept of 0.

> It genuinely makes me mad to have this low quality discussion, where someone barges in and gives you a trivial "gotcha" as if I wasn't completely aware of that fact. And when you try to point out why the person didn't understand what you were saying you are getting another person debating the stupid gotcha, as if it even mattered.

I'm sorry you're mad but I mostly disagree on your assessment of the quality of the discussion. Your top-level comment on the article about Mesopotamia creating nought was essentially that Greek geometers knew about it and that tying concepts and geographical locations seems odd.

I don't disagree with your second point, but we may be in the minority: lots of people are very interested in knowing who had what ideas first and where. Your first point doesn't stand well alone without the further elaboration you've made through the rest of this discussion. With the elaborations you've made since the rest of this thread might not have happened.

> No. They weren't even in the same category, even the comparison doesn't make sense.

The comparison does make sense if you interpret the parent’s post simply to state that Babylonian mathematics (in Mesopotamia) were developed (and seemingly stagnated) before Greek mathematics began in earnest. Which seems to be pretty uncontroversial. There are extant clay tablets from 1800 to 1600 BC that would indeed predate the Greek Geometers by a millennia — and that’s if you’re counting Thales as the beginning.

Ie. your parent post is using “ahead of” == “temporally before” not as in “more advanced”.

> If it were true free market forces would already gone 100% solar because the purpose of energy companies is to make money.

I’m not going to speak on whether solar truly is the cheapest form of energy as I have no idea whether or not that is the case. But I’m going to suggest that one of your premises is wrong: we don’t have a true free market in energy — see all of the subsidies that gas, oil, and coal companies have gotten (for quite some time).

Yes, solar gets subsidies, too, but comparing a relative newcomer to entrenched players makes this a lot less clear of a picture than you’re painting.

https://en.m.wikipedia.org/wiki/Fossil_fuel_subsidies

> My real, true first exposure to programming was Qbasic on a Windows XP machine, followed by real BASIC on a Commodore 64, then Java.

What’s the story behind your starting with Windows XP and then moving back to a Commodore 64?

For me, by the time Windows XP rolled around, my Commodore (128 not 64) was sadly long gone — given away at a garage sale by my parents while I was off at college.

> Anything that "gratifies one's intellectual curiosity" is on-topic on HN :)

Yeah — sure. But I’m with the parent comment to which you replied. Sometimes I’m not sure if I’m just coming across one of todays “lucky 10,000” [0] or if there’s another reason why something old has resurfaced and, if it’s the latter, it’d be nice to know the context.

[0] https://xkcd.com/1053/

Your analogy is flawed. Maple syrup is not to jam or honey as XXO Cognac is to regular brandy.

A better analogy is that maple syrup is to jam or honey as brandy is to beer.

Yeah — they have the same sort of fundamental purpose but if your recipe or drink calls for wine you probably don’t want to substitute beer or vice versa.

> I mean... most European countries (modulo some exceptions like Germany) existed (non-continuously) for at least a thousand years.

This is interesting to me. What does it mean for a country to exist non-continuously? I can understand making the case under some sort of continuity despite dramatic changes in e.g. control of land or type of government. Sort of like a nation-state Ship of Theseus.

But I don't understand how this works under the non-continuous case. If the temporal connection is broken how is it the same entity?

To be fair AMD has a graphics card with the model name 7900XT so the names aren’t that far apart in Levenshtein distance.

This appears to be the correct link:

https://www.theatlantic.com/magazine/archive/2024/03/silicon...

(When I read the title, I thought the story was going to be about Rome — it is not)

As the sibling comment from zeeed mentioned, yes — in this case.

More generally maybe but not always. If you wanted to use a DRFM jammer to insert false targets in an imaging radar, the bandwidths required may be a challenge.

There are commercial SAR satellite operators that you (for some definition of you — I personally couldn’t afford it) can buy from that sell imagery that’s got a resolution of 0.5 meters per pixel. That would require a bandwidth of about 300MHz. I haven’t looked at the SDR landscape in awhile but when I did that was sort of sporty — by that I mean >300 complex megasamples a second (for Nyquist, not including any oversampling).

And that would be after basebanding in analog before sampling to digital.

> Spoofing radar signals isn't exactly new, and the ability to do it on the ground (so to speak) shouldn't be surprising. The military has been doing it for decades.

People who are interested in finding out more can look up Digital Radio Frequency Memory (DRFM) jammers.

https://en.wikipedia.org/wiki/Digital_radio_frequency_memory

I don't mean to sound pessimistic, but the link's assertion that any of these techniques are new suggests that either allaboutcircuits is not familiar with radar/electronic attack or that Duke University and/or the automative radar folks are not up to speed with techniques used in radar/electronic attack in the defense/aerospace industries. Maybe it's the latter, as the arXiv preprint states "...show the novel ability to effectively ‘add’ (i.e., false positive attacks), ‘remove’ (i.e., false negative attacks), or ‘move’ (i.e., translation attacks) object detections...".

These are open data, too. See https://en.wikipedia.org/wiki/Radar_jamming_and_deception.

The arXiv preprint doesn't list any of the usual suspects for radar or electronic attack sources that I would expect to see in its references. There are a lot of automotive radar sources and, interestingly enough, some LiDAR and LiDAR adversarial attacks instead.

> I am conflicted on this because I like to speak my mind.

> However, I do worry that there is too much criticism these days when someone speaks their mind.

You don’t need to feel conflicted. Just think of that “too much criticism” as people who disagree with the initial take as speaking their mind in response.

Alternatively you could think of the value added as the general contractor is you loaning the subcontractor your reputation. Certainly that reputation should be on the line if the sub (and by extension the general) fails to deliver.

Though from what I hear this isn’t necessarily the case in construction / home improvement.

But in any case, if you can’t close the deal yourself, 70-85% of something sounds better than 100% of nothing.

My reputation is worth a fair amount to me, but I’ve never been a general or sub contractor though so my opinion is probably pretty naïve.

Vouched for this. Not sure why it was flagged. Maybe because it was an article originally from arstechnica rather than pocket.

https://arstechnica.com/science/2022/01/the-most-important-c...

> In addition, point 4 in the article does not make much sense. Why would a Russian victory 'encourage' mainland China to invade Taiwan, for instance? It wouldn't change anything there.

Point 4 makes sense to me — though I’m certainly no expert in international affairs. What it says to me is something about the world as a whole rather than something particularly about China and Taiwan. It says that the powers that be who are interested in maintaining the status quo in the world are either unwilling or unable to enforce continuing adherence to it.

That could certainly embolden countries that are unhappy with the status quo but have until now been unwilling to challenge it.

> it's based on the logic of taking away from people who have, and giving to those who don't, which means taking away from those people who found purpose, and giving to those who don't and usually don't seek purpose but instead search for temporarily pleasures like alcohol

I’m with you in your opinion that government shouldn’t try to give people purpose but I think the last part of your argument is an overreach.

You’re conflating purpose with making money. They’re not the same. Counterexample: Vincent van Gogh. His purpose was clearly art but he did not see professional success while alive. If you don’t consider Van Gogh’s purpose to be something like painting or art then I’d suggest you’re not using the word as it is commonly defined.

Also I’d suggest that it’s unfair to paint the poor broadly as not seeking purpose and instead searching for temporary pleasures. I have simultaneously known both an economically struggling person who refrains from drugs and alcohol and a well-to-do person who is a functional alcoholic.

Certainly alcoholism can make people lose money, relationships, etc. But it does not follow that simply abstaining from these things will make one wealthy.

I disagree. Science would suggest that separating a human from their emotions (like via emotional suppression) is illogical — a one-way ticket to mental health disorder. Thus, to obey reason, one must feel enough (and regulate vs suppress those feelings).

> Do we really need to be using up government resources doing drug approvals for dogs? It takes so long to get human drugs approved. Let's use the resources there and let the market sort out what works for animals.

Let’s leave aside the fact that humans value companion animals such that they might want to spend government resources on keeping them healthy for longer. And also the fact that certain other animals are important food sources which make up a sizable chunk of the economy.

Do you think that if the government no longer had to spend resources on animal drugs that all of those resources would stay at the FDA and be diverted to human drugs?

The cynic in me thinks that the speed of the process is the independent variable here. And that resources will be added or subtracted to maintain roughly that same speed and/or rigor.

The two antennas on the desk are set up as an array (Input A and Input B). The beamformer (that little disc) creates two outputs, a sum channel (A+B) and a delta channel (A-B). Where the -B part is essentially inverting the phase of B and adding that to A. The delta channel is plugged into the network analyzer for display (or oscilloscope -- I didn't pay too much attention as to which it was).

The diagram to the left shows the theoretical beam patterns of the output: the orange is the sum channel and the blue is the delta channel. The delta channel has a deep null where the sum channel has a peak.

The poster turns on a transmitting antenna and sweeps it in angle past the array. The output is very low when the transmitter is directly between the receive antennas -- as expected (ideally it would be zero, but any phase or amplitude mismatches between the two antennas would reduce the depth of the null).

The first pass he makes doesn't show as large of a dip as expected -- probably because he's in the near-field of the array. You'd typically want to be in the far field and there's a rule of thumb based on the size of the array as well as the wavelength. He moves the transmitter back a bit on subsequent passes and it shows a bit deeper of a null.

I would call this a "poor man's monopulse" (monopulse being a keyword if you'd like to search further). If you have, say, a very large array and you're using it for radar, you would often apply some sort of amplitude and phase weighting across the receive elements on the "sum" channel to control sidelobes. Otherwise, strong signals coming in from angles not associated with the mainbeam can be mistaken for signals in the mainbeam. You would ideally match your delta channel weighting to your sum channel weighting.

Monopulse in radar is used to improve angle estimation. Radar is very good at ranging: you transmit a signal and time how long it takes until you receive it and the speed of light is a well-known quantity. But the cross-range error is poor: you want a very large antenna to give you a very fine beam and to translate that to cross-range error. For example, you may easily be able to range something to within 10 meters, but with a 2 degree beam width at 20km, your cross-range error would be on the order of 750m. Monopulse, for nominal signal-to-noise ratios, can give you angle accuracy roughly 10x better than real-beam -- so in our example you might have 75m cross-range error with monopulse. Still not great, but much better than 750m.

So you'd perform your detection on the sum beam, and then you'd essentially look at the ratio of delta / sum to get a better estimate of the angle within the mainbeam.

Note: I'm not an antenna engineer, but I do make use of antennas in my field.

I was under the impression that Starlink satellites were Ku/Ka band (and E-band, apparently) according to Wikipedia.

Isn’t LTE in L-/S-band? Is the plan to launch new satellites that also have LTE band or do previously launched satellites have a previously unknown LTE band subsystem?

[0] https://en.m.wikipedia.org/wiki/Starlink

Edit: Guess I should have looked a little harder. Here’s a reference to the Gen2 satellites with LTE

https://www.extremetech.com/extreme/341576-spacex-asks-fcc-t...

For me the link just went to that site’s homepage which aggregates all of the stories there. This link seems to be what the poster may have intended?

https://news.artnet.com/opinion/devon-rodriguez-parasocial-a...

> I feel sorry for Jake. This post is titled "The patient's perspective" but the only part that referred to his view was him saying he was too worn out to do more than a couple of flights. I'm not on the inside of the family but I wonder if the author is pushing the trial much more than the patient. I hope not.

You needn’t wonder too much, you can satisfy your desire to know by simply reading Jake’s blog if you like.

Not sure if there was a link to it on the posted article, or if it was linked from one of the other parts in the series.

https://jakeseliger.com/

> Because their primary purpose was to provide open access to literature and information, which is now widely available thanks to the internet.

Even if you reduce a library to this primary purpose (and maintain that’s it purpose must be static for time immemorial), there are still people that don’t use the internet.

Some can’t. Some think they can’t. Some just won’t. Some don’t have affordable access. Some don’t have access at all.

Libraries still fulfill this information access purpose to a not-insignicant portion of the population in the US.

I think we’re in a bubble here where our idea of minimal computer / internet skills can greatly diverge from the reality of the broader community around us.

And that’s not even touching on the other reasons I listed in my original comment about why libraries still matter.

> How much do libraries matter now? Hard to say they matter as much as several decades ago.

Why wouldn’t they? Is the idea that a person can get any content a library might offer online (and for free, if willing to pirate it)? I can’t disagree with that, though if you’re not ok with pirating things then I think the value is enormous.

I think libraries are more than just the sum of the books, CDs, and DVDs on the shelves. In my experience they often have discounts to area activities (e.g., museums), offer classes and activities across the age spectrum (from story time for children to tech help geared toward the elderly or just the tech disinclined), and provide a nexus for community.

I think folks that haven’t been to a library in awhile would be pleasantly surprised with what they offer nowadays — though of course I only have personal experience with libraries across a few states in the northeast. It’s totally possible that I’m spoiled and don’t even know it.

I found a related journal article about sandfly distribution but I am in no position to evaluate it (I’m neither a climatologist nor an entomologist — and I have no desire to play one on the internet).

https://journals.plos.org/plosntds/article?id=10.1371/journa...

> Can you elaborate on how climate change caused this as opposed to it having very obviously been inevitably sourced from typical travel and immigration across decades?

This quote is directly from the article:

“ One factor driving the disease’s northward creep may be climate change. “It’s increasing the likelihood sand flies can move further north,” Molyneux says. “They thrive in warm conditions.” Climate modeling suggests this trend will continue.”

You’re in good company misinterpreting Truman’s famous desk sign:

https://nymag.com/intelligencer/2012/10/buck-stops-here-clin...

Or directly from Truman’s library:

“In his farewell address to the American people given in January 1953, President Truman referred to this concept very specifically in asserting that, "The President--whoever he is--has to decide. He can't pass the buck to anybody. No one else can do the deciding for him. That's his job.”

Funny enough, Trump gave his own version of the phrase around the looming 2019 shutdown with “the buck stops with everyone”.

> It's truly pathetic how Congress and the media are giving the Biden administration a free pass on refusing to acknowledge that the endless interest-rate hikes AREN'T WORKING.

The President doesn’t control interest rates, the Federal Reserve does. And the President does not control the Federal Reserve. The President nominates the board of governors and the Senate confirms them.

The current Federal Reserve chair is actually a Republican first nominated by Trump and then nominated for a second term by Biden (in fact, against pressure from the more left-leaning Democrats like AOC and Warren).

Laying the interest rate hikes solely at the Biden administration’s feet expresses a lack of understanding about how the Federal Reserve and interest rates work in the US.

There’s plenty of blame to go around here.

Edit: here’s a link to the vote for the current chair’s renomination (https://www.senate.gov/legislative/LIS/roll_call_votes/vote1...)

I think it’s interesting because you see as diverse a group as Cruz, Hawley, Rubio, Sanders, and Warren voting together (nays) against the overwhelming majority of yeas (80 to 19 with 1 senator abstaining).

> Sorry but I can't buy into using history to compare if an empire is collapsing or not

The point isn’t that history is the perfect tool for predicting collapse — it’s not. The point is it’s seemingly the best tool we have at this time.

What would you suggest as an alternative? Gut feeling? Intuition? “Logic”?

The last I deliberately put in scare quotes because there’s no from-first-principles mathematical / logical model of this that accounts for all of these things (and I kind of doubt there can be). And even if it was possible to create one, there isn’t one now and one has to navigate the world in its absence.