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Joined 3 年前
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Cake day: 2023年6月14日

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  • I did a course in photolithography, including a lab session where I literally made an unpackaged ASIC by hand, using technology that was current in the mid 90s. Etching silicon and doing photolithography is completely out of the reach for a hobbyist, even from scratch, even with 30 year old technology. Reusing a random chip and adding to it is simply impossible.

    Essentially, you are looking at the following problems with simply creating a new chip:

    1. Need access to a large clean room
    2. Need a furnace that can heat up your silicon wafers to silly temperatures in order to do doping via sputtering.
    3. Need chemical handling equipment, including safety gear required for handling hydrofluoric acid.
    4. Need a photolithography device with your designs.
    5. Need to cut, test, and package chips after they are created.

    And the additional problems with using an existing chip:

    1. Need to decapitate the existing chip and remove it from the package.
    2. Need to work with a single already sliced chip instead of a wafer.
    3. A completed chip will have metal vias that cover a large portion of the silicon, you would need to perform your chemical etching without harming these or any silicon that has been used.
    4. Generally, Asics don’t have wasted space, but simply larger components. There would be no footprint available for your design, even if your hobbyist tooling was smaller than the one used for the components, which is probably wouldn’t be.


  • I suppose that the most likely scenario is that the evidence was something that Tesla provided to the police. Whether or not it was tampered with is an open question though. Teslas are equipped with a gorzillion cameras, but also Tesla has access to deep fake technology. Tesla says that the guy manually deactivated autopilot then slammed the accelerator and drove right into a house. But he wasn’t intoxicated and it’s not clear why he would intentionally do such a thing. It wasn’t late enough that it was likely to be the guy simply falling asleep at the wheel.

    Anyway, it would be very interesting if Tesla fabricated the driver turning off autopilot intentionally to save face/dodge consequences, but I don’t know how likely that would be.


  • OmnipotentEntity@beehaw.orgtoScience Memes@mander.xyz•Aha!
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    4 个月前

    If you floss regularly your gums won’t bleed, source: me. My gums never bleed at the dentist, but they used to when I sucked more at dental self-care.

    For the X-ray example, think about it this way: the doctor is like a bartender. One drink isn’t going to hurt you. The bartender can definitely serve you one drink. But if the bartender had to drink a part of a drink every time they served someone, that would become pretty dangerous for them indeed.










  • OmnipotentEntity@beehaw.orgto196@lemmy.blahaj.zone•Rule
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    2 年前

    Careful ⚠️ there is not guaranteed to be an element such that |🍎(x) - 🍇(x)| is maximized. Consider 🍎 (x) = x if x < 3, 0 otherwise. Let 🍇 (x) = 0, and let the domain be [0, 4]. Clearly, the sup(|🍎 (x) - 🍇 (x)| : x ∈ [0, 4]) = 3, but there is no concrete value of x that will return this result. If you wish to demonstrate this in this manner, you will need to introduce an 🐘 > 0 and do some pedantic limit work.


  • OmnipotentEntity@beehaw.orgto196@lemmy.blahaj.zone•Rule
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    2 年前

    Anyway, to prove this is a metric we must prove that it satisfies the 4 laws of metrics.

    1. The distance from a point to itself is zero. 🍊 (🍎, 🍎) = 0

    This can be accomplished by simply observing that |🍎 (x) - 🍎 (x)| = 0 ∀x ∈ [a,b], so its sup = 0.

    2. The distance between any two distinct points is non-negative.

    If 🍎 ≠ 🍌, then ∃x ∈ [a,b] such that 🍎 (x) ≠ 🍌 (x). Thus for this point |🍎 (x) - 🍌 (x)| > 0 and the sup > 0.

    3. 🍊 (🍎, 🍌) = 🍊 (🍌, 🍎) ∀(🍎, 🍌) in our space of functions.

    Again, we must simply apply the definition of 🍊 observing that ∀x ∈ [a,b] |🍎 (x) - 🍌 (x)| = |🍌 (x) - 🍎 (x)|, and the sup of two equal sets is equal.

    4. Triangle inequality, for any triple of functions (🍎, 🍌, 🍇), 🍊 (🍎, 🍌) + 🍊 (🍌, 🍇) ≥ 🍊 (🍎, 🍇)

    For any (🐁, 🐈, 🐕) ∈ ℝ³ it is well known that |🐁 - 🐕| ≤ |🐁 - 🐈| + |🐈 - 🐕|, (triangle inequality of absolute values).

    Further, for any two functions 🍍, 🍑 we have sup({🍍 (x) : x ∈ [a, b]}) + sup({🍑 (x) : x ∈ [a, b]}) ≥ sup({🍍 (x) + 🍑 (x) : x ∈ [a, b]})

    Letting 🍍 (x) = |🍎 (x) - 🍌 (x)|, and 🍑 (x) = |🍌 (x) - 🍇 (x)|, we have the following chain of implications:

    🍊 (🍎, 🍌) + 🍊 (🍌, 🍇) = sup(🍍 (x) : x ∈ [a, b]}) + sup({🍑 (x) : x ∈ [a, b]}) ≥ sup({🍍 (x) + 🍑 (x) : x ∈ [a, b]}) ≥ sup({🍎 (x) - 🍇 (x)| : x ∈ [a, b]) = 🍊 (🍎, 🍇)

    Taking the far left and far right side of this chain we have our triangles inequality that we seek.

    Because 🍊 satisfies all four requirements it is a metric. QED.

    QED stands for 👸⚡💎, naturally