Category Archives: Pseudorandom

The Scanning and Location Problem

A couple weeks ago, I posted a math problem that I was playing around with. This problem was born of our some ideas for my new role-playing game, as well as the basic scanning mechanism of EVE Online.

In EVE Online, if you are trying to scan down an object in space, you launch some probes and they report back the distance from the probe to the anomaly, with some amount of error, up to some maximum range. Your ship’s computer then aggregates that information and renders it as an overlay on the scanning screen. If two of your probes received responses, you would get a circle where the two spheres intersect, with three you would get two points, and with four you would get a single point (with some degree of error). You then decrease the range of the probes (increasing their signal strength) to narrow in on your target – a pretty simple and fun min-game which tickles my imagination and makes me think I know something about how science fiction scanning might occur. Continue reading The Scanning and Location Problem

A Solution for the Mathematically Inclined

The answer to my post last week is yes. Here’s the quick (intuitive) proof:

First, note that math_a and math_b is the surface of two spheres in three dimensions, and their intersection is either a circle or a point (we know they are not the same sphere since a and b are distinct and that they must intersect because we know p exists).  If it is a point, then p is that point (and since we have not used gamma we have proved the hypothesis).

If the intersection is a circle, it intersects the plane containing a, b, and c at two points, but only one is inside the triangular prism, and that must be the point p. We know it cannot be a point not on the plane, since if it was, two points would satisfy math_c, and not satisfy the uniqueness condition.

I personally prefer algebraic proofs though, so let’s crank some algebra! Continue reading A Solution for the Mathematically Inclined

For the Mathematically Inclined

I’ve been thinking about the following math problem lately (I occasionally get distracted by such things):

Suppose you have four points in 3D space, a, b, c, and p, where a, b, and c are distinct and non-colinear and their positions are known, and p is the unique point defined by the following:

  1. math_a
  2. math_b
  3. math_c
  4. p lies in the interior of the triangular prism defined by a, b, and c that is perpendicular to the plane containing a, b, and c.

As an image:

math_diagram

If there is only one point satisfying the above criteria, can it be found without knowing γ?  I plan on posting my proof next week Thursday, 2016-02-25.

Blogs with Text

As I’ve been writing the last few months, I’ve noticed a very particular pattern about my posts: most of them are entirely text. It took me a bit to notice this, and, in fact, my Gamerstable blog was the wake-up call. That entry made it live without a single hyperlink. I noticed it later when I reread that entry and said to myself, “I just spent a whole blog entry talking about my favorite podcast, and I never once linked to it… …That is a problem.”

This, I think, is the result of two factors of my writing. First, as I’ve mentioned before, I write on my bus ride to work where I do not have internet access. Second, my personal style is to say things with words rather than other expressive elements. Continue reading Blogs with Text