If your sensor travelled at constant speed along a straight line, the algebra will declare that the target was right on top of your sensor at each detection, because that satisfies the constraints, regardless of rounding errors in the bearings.
8/ Adding a dogleg to the sensor path fixes the problem, but there remains an uncomfortably large error of 246 units in the computed target position in this example using a relatively slow-moving sensor.
The computed target course is correct. Computed speed under by 8%.
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1/ SONAR problem
Your UUV on patrol has detected a target four times as shown. Assuming that that this is one target travelling at constant course and speed, what is its course and latest detected position?
2/ The position (p, q) of your sensor at each detection event is listed below, along with time of detection and bearing to target.
3/ Offered solution: target is at (452, 119) course 119 degrees speed 9.9
1/ A question have been asking myself: When infections hit multiple family members (e.g. as a result of home quarantine of mild cases) what are the chances of orphaning any children?
(thread)
2/ For any infected person (incl. undiagnosed/mild), the probability of this doubly tragic outcome is:
Cohort IFR x cohort IFR x (probability of transmission)
some guesses using IFR for older folks
a) 0.5% x 0.5% x 60% = 15 per million
b) 1% x 1% x 80% = 80 per million
3/ For a clinically confirmed case, the formula changes to:
Your CFR x partner's IFR x (probability of transmission before isolation)
a) 2% x 0.5% x 40% = 40 per million
b) 2.5% x 1% x 50% = 125 per million
A survey of CENTRALIZED QUARANTINE (CQ) practices, or lack thereof
Background: Wuhan first tried home quarantine, part of standard epi procedure, but found that these ‘mild’ patients were
*infecting their families.*
1/
2/ Centralized quarantine (CQ) means infected people not needing hospitals stay in govt-run facilities where they are to some degree physically detained.
3/ Singapore at first neglected, but has now adopted centralized quarantine (CQ.)
Because their 2nd wave of imported cases had a direct 2x or so multiplier effect in home quarantine.
This March 2, 2019, image is the last published on @38North of the Sohae engine test stand without its post-Hanoi white cladding.
(source: 38north.org/2019/03/sohae0…) 1/
@38north 2/
By March 6, everything had been closed up. Unless this thing has been torn up in the last 9 months without anyone noticing, the structure remains unchanged. Barring this, I assert that this stand could not have mounted a solid motor vertically.
No further construction at the test stand has been reported from March.
However, there was an addition of what looks like office/lab space at the horizontal assembly facility, begun before January, roofed over May 2019. (38north.org/2019/05/sohae0…)