Ionospheric simulation compared with Dynamics Explorer observations for November 22, 1981

Hans Adolf Krebs: 25 August 1900-22 November 1981.

Lecture 22 — November 19 , 2015

In terms of exact numbers, hard drives support somewhere around 140MB/sec of sequential reads/writes, but only 120I/O’s/sec when doing reads/writes on random 4KB chunks. This is because the disk must physically spin to the read/write location. RAM supports somewhere around 5-10GB/sec of reads/writes, with much less penalty for random access. SSDs/Flash is somewhere in the middle, but with the i...

Lecture 22 — November 5 , 2013

This is sometimes called the Netflix problem. A motivation for the matrix completion problem comes from user ratings of some products which are put into a matrix M . The entries Mij of the matrix correspond to the j’th user’s rating of product i. We assume that there exists an ideal matrix that encodes the ratings of all the products by all the users. However, it is not possible to ask every us...

Meteor science from ionospheric observations

Introduction Conclusions References Tables Figures Back Close Abstract Introduction Conclusions References Tables Figures Back Close Abstract We report the observation and analysis of ionization flashes associated with the decay of meteoroids (so-called head echos) detected by the Arecibo 430 MHz radar during regular ionospheric observations in the spring and autumn equinoxes. These two periods...

Beta Pic b the transiting planet of November 1981 ?

In 1981, β Pictoris showed strong and rapid photometric variations that were attributed to the transit of a giant comet or a planet orbiting at several AUs. Recently, a candidate planet has been identified by imagery in the circumstellar disk of β Pictoris. This planet, named β Pic b, is observed at a projected distance of 8 AU from the central star. It is therefore a plausible candidate for th...