hchenji

5 ms·

1.
by hchenji 9y ago
very interesting!! Do you have a source for this? Would like to read up on it
2.
by hchenji 9y ago
Yes. See Haar Basis on page 4 of http://www.fourierandwavelets.org/FSP_v1.1_2014.pdf
3.
by hchenji 10y ago
Lectures and video from http://www.cse.wustl.edu/~jain/cse574-16/index.html Book: https://www.pearsonhighered.com/program/Beard-Wireless-Commu...
4.
by hchenji 10y ago
In my experience WiFi clients at 2.4GHz never end up using the high MCS indices whenever they transmit (whenever the channel is clear). This has something to do with the fact that the CCA thresholds are fairly high, and that high SNR (30-50
5.
by hchenji 10y ago
See my comment https://news.ycombinator.com/item?id=13793876 . I suggest reading Andrea Goldsmith's or Pramod Vishwanath's book on Wireless Communication. If not, Intro to Communication Systems by Madhow is recomm
6.
by hchenji 10y ago
Reducing transmit power reduces interference, but it also reduces capacity since the received power (and hence the SNR at the receiver) is reduced! The Shannon limit on channel capacity dictates exactly how much bit rate (C=B*log2(1+SNR)) i
7.
by hchenji 10y ago
802.11ax won't mean anything unless you reduce interference (see my reply below). Without high SNR, all these new efficiency techniques won't get you anything. Shannon capacity is still what limits performance.
8.
by hchenji 10y ago
The article misses out on explaining WHY we cannot get the promised bitrates. The answer is Shannon's limit on channel capacity, which mandates that you pay in either bandwidth or high power or low noise (SNR) to get higher capacity. N
9.
by hchenji 10y ago
No, since wired networks are full duplex and are their own collision domains. No need to do carrier sensing at all.
10.
by hchenji 10y ago
You mean like 3G/4G/LTE?
11.
by hchenji 10y ago
You can also do channel bonding on 5G and use 40MHz channels. Almost double the capacity!
12.
by hchenji 10y ago
Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway. — Tanenbaum, Andrew S. (1989). Computer Networks. New Jersey: Prentice-Hall. p. 57. ISBN 0-13-166836-6.
13.
by hchenji 10y ago
What would be more interesting is the internals of numpy. What is it that makes numpy 'blazing fast'? Instead, there is only high school level math in the article, with dot products and matrices and so on.
14.
by hchenji 10y ago
Then why not Dijkstra + source routing?
15.
by hchenji 10y ago
Use a Pseudoinverse or a decomposition instead. A great book to read is Matrix Computations by Golub/van Loan.
16.
by hchenji 10y ago
Any idea why they chose DV based routing? Looks like they have ignored about 20 years of Wireless Sensor Networks/cyber-physical systems research.
17.
by hchenji 11y ago
Interesting read. Could you blog about the math/techniques/algorithms you used to determine the best fiber paths? Consider writing a SIGCOMM paper about it!!
18.
by hchenji 11y ago
Why doesn't the article mention Southwest Airlines??
19.
by hchenji 11y ago
So can we use it in a macbook somehow with a usb air interface?
20.
by hchenji 11y ago
EE degrees yes definitely. I wish CS students learnt it too. Every fancy language du jour eventually has to generate machine code after all.
21.
by hchenji 11y ago
Yeah but if GNULinux is free in the first place, why spend so much govt. money on it?
22.
by hchenji 11y ago
Just because borders are open does not mean that people will immediately move. That said, CA and RI have similar quality of life, but Africa and North American probably do not. So CA/RI is not a good example.
23.
by hchenji 11y ago
https://www.numbersusa.com/
24.
by hchenji 11y ago
Yes I agree...instead of importing low skilled labor, we should import highly skilled immigrants. Increasing the H1B and employment based greencard quotas is absolutely necessary.
25.
by hchenji 11y ago
The Wire (season 2) gives an excellent insight into how docks are run (Baltimore). There's even a scene where some Dutch company wants to bring Rotterdam's automation to Baltimore.
26.
by hchenji 11y ago
Is this new or has it existed since some time?
27.
by hchenji 11y ago
Why should we care how the science was applied? '"Once the rockets are up, who cares where they come down That's not my department," - says Wernher von Braun' - Tom Lehrer
28.
by hchenji 11y ago
Nice explanation. Is there any literature that explains how faces are stored in memory? Fascinating.
29.
by hchenji 11y ago
Why can't we just do it in hardware/FGPAs at that point?
30.
by hchenji 11y ago
Anyone know if the font rendering issue was fixed? The email reading pane in Outlook (on Windows) didn't do any subpixel smoothing, and so the fonts looked fugly as a result. Hopefully they fixed it. Office for Mac 2016 doesn't se

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