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mumumu

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Passive Daytime Radiative Cooling

en.wikipedia.org
1 points·by mumumu·3년 전·0 comments

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mumumu
·3년 전·discuss
In hardware engineering this is called critical path.
mumumu
·3년 전·discuss
Amdahl's law is common sense, but also the one of the reasons premature optimization is the root of all evil.

A small speedup on the longest (by time) part of the program is usually better than infinite speedup on a short part of the program.
mumumu
·3년 전·discuss
It seems the limit does not apply to Quotes and Liked tab on users profiles.
mumumu
·3년 전·discuss
The bottleneck is bandwidth and storage not computer power.

Data from sensor and to display are usually (but not always) raw and uncompressed.

To go beyond 8k 120fps we will need fiber, or better compression.

We have good codecs to move data online. And specialized ASIC to do live encoding with good quality.

The current compression defined by HDMI is very rudimentary.
mumumu
·3년 전·discuss
Flow instability is one of the biggest challenges to get them to operate for long time without blowing up. Of course, there are others.

Any progress on the control of chaotic flow is great news. Even at subsonic speed.
mumumu
·3년 전·discuss
Also detonation. It Could make Rotation Detonation Engines possible.
mumumu
·3년 전·discuss
“[Balloons] have extremely small radar and thermal cross sections, making them relatively invulnerable to most traditional tracking and targeting method".

https://www.thedrive.com/the-war-zone/why-shooting-down-chin...
mumumu
·3년 전·discuss
They have smaller cross section than many stealth jets:

https://www.thedrive.com/the-war-zone/why-shooting-down-chin...
mumumu
·3년 전·discuss
Alder Lake and Raptor Lake workstation (W680 Chipset) doesn't have AVX512 enabled.
mumumu
·3년 전·discuss
Now we only need a consumer CPU from Intel with AVX-512 enabled.
mumumu
·3년 전·discuss
I don't think Apple has interest in small markets. They are really good at making stuff at huge volumes.
mumumu
·3년 전·discuss
Silicon on lunar regolith is mostly plagioclase, pyroxene, and olivine. Quartz (SiO2) is <1%.

Not exactly comparable.
mumumu
·3년 전·discuss
The aviation industry is averse to change. Most planes are still being updated with floppy disk.

But I agree. High end commercial solid storage, such Optane, would likely exceeds the requirements needed by the aviation industry.
mumumu
·3년 전·discuss
I wish the Sony protocol was open source. It is impossible for a hobbyist to work with SLVS-EC.
mumumu
·3년 전·discuss
*avoid branches

The blog post I mentioned:

Paper: Parsing Gigabytes of JSON per Second https://branchfree.org/2019/02/25/paper-parsing-gigabytes-of...

Another related post from Lemire:

Ridiculously fast unicode (UTF-8) validation https://lemire.me/blog/2020/10/20/ridiculously-fast-unicode-...

Those algorithms are fast. But to put them in perspective. A single x86 CPU can write 64B per cycle. At 5GHz, the theorical maximum bandwidth is 320 GBps. IIRC, the read bandwidth is twice that.

There are others botlenecks, and is very hard to write code that writes at every cycle.

A interesting consequence, is that the theorical maximum bandwidth is logarithmical to the number of cycles. Again, talking about branchless streaming application.
mumumu
·3년 전·discuss
This is true on a few streaming application (such as parsing).

And most of the speedup is because of tricks to avoid doing beaches. There is a great blog post from one of the authors of JSON SIMD discussing this.

I'm on mobile, there is a link for the blog post on the simd JSON github repository.
mumumu
·4년 전·discuss
CPUs with high power and high performance gets binned into mobile and iot sku.

But those i9 ks sku can achieve a couple hundred extra MHz. But have a much higher base clock speed.
mumumu
·4년 전·discuss
From a quick search, it seems to be due the Radon gas.

Exposure to Radon is the #1 cause of lung cancer on non-smoker. Canada ranks third on indoor radon concentration worldwide.
mumumu
·4년 전·discuss
Astronomical cameras and microscope cameras are affordable. Some of them mm support sensors that uses them even supports Sony's proprietary protocol.

A lot of sbc boards support MIPI CSI (iirc even RPI). Nvidia robotic modules has IO for Sony's LVDS (driver not provided though).
mumumu
·4년 전·discuss
They can gather this data through other means...