On this Earth Day I’m preparing to start a new job, one full of IT management buzzwords like continuous inspection (CI), continuous integration (my other brother, CI) and continuous delivery (CD). When making policy towards our homeworld though, it strikes me that these proven management practices fall by the wayside of many “pro-business” policymakers. What does CI for earth science really mean? Continue reading

# Author Archives: Derek Harmon

# Shellvarnia: Shell Variables Down Unix

This is a fun short story about the fictional land of Shellvarnia, located Down Unix, that occurred to me one night while I was reading Brian Ward‘s excellent book, How Linux Works: What Every Superuser Should Know. Mixing one dash of political satire with a heaping serving of Unix lore, it will entertain and inform novices approaching a Linux VM for the first time. If you’ve ever wondered about distinctions between **local shell variables** and **environment variables**, /bin/sh from /bin/csh, and who built that wall between Shellvarnia and Environmentopia, then this story was written just for you. Continue reading

# Birthday Paradox

A math magician appears before you on the street in a puff of smoke, and he will make you his apprentice if you can but answer one question. You fantasize how you could make your investment portfolio grow if only you knew magic, or how you could star in your own series of blockbuster films–move aside Harry Potter! But before you get carried away, the magician posits his question to you: how many people off of the street do I need to invite to my magic show to have a 50% chance that any two of them celebrate their birthday on the same day? You sweat a little, think a little, then sweat a little more before answering: 183.

You won’t be attending Hogwarts anytime soon, my friend. You’ve been hit by, you’ve been struck by, a Birthday Paradox! Continue reading

# When Averages Attack: For the Love of Means

Americans love the **average**. Ask the average american on the street what he knows of statistics, and they will probably answer in so many words about something relating to an average (**arithmetic mean**). An average describes for us the central tendency of some data; the whole distribution of whose values we find it easier not to remember. Yet averages have a darkside to them, beyond sunny days on a baseball diamond figuring your favorite batter’s batting average. Let us look at statistics… when averages attack! Continue reading

# What was Good for General Motors?

This Groundhog’s Day I revisit the Senate Armed Forces Committee 1953 confirmation hearing of highly-paid General Motors CEO, “Engine” Charles E. Wilson. How different are today’s governmental ethics concerns from those of our grandparents? Continue reading

# Subresource Integrity – The Cyber Defense of 2016 You Haven’t Heard Of

As we make plans this New Year’s Eve to bid farewell to 2016, we’re continually beleaguered by headlines concerning cyber attacks. The stories range from the latest allegations of Russian malware found on a Vermont utility’s computer, to leaked e-mails ahead of the U.S. Presidential Election, and you could even include Apple’s refusal earlier this year to furnish U.S. Government law enforcement agencies with a backdoor they insisted upon to enable encrypted data access. Cybersecurity must go down as one of the leading themes of 2016, and likely will go on to concern us for years to come.

That’s why we should take a moment to recognize a most important development within the information security community during 2016: the publication of the Subresource Integrity (SRI) recommendation by the W3C. Continue reading

# Poor User Experience of Self-Checkout Kiosks

I was paying a *return* visit to a local Safeway supermarket to buy a refreshing **refreshe** Apple Cider sparkling water to take sanctuary from the oppressive heat outside this afternoon. I was hopeful of scoring a powerful discount on two bottles because I had received a 50 cent off coupon (if you buy 2) earlier that day. My story turned to sour apples at the self-checkout kiosk. Continue reading

# An Infinite Sum Approximation of Pi

The value of Pi rounded to four decimal places is 3.1416, which makes today (3/14/16) one of the most prominent **International Pi Days** you’ll experience in your lifetime. This year I’m looking at Issac Newton’s infinite series approximation for π. Originating in the long ago 1730s, it’s still one of the fastest converging Pi approximations to this day. Continue reading

# Finding the Golden Ratio from the Fibonacci Sequence

Technical analysis teaches traders to use Fibonacci retracement price levels (61.8%, 38.2%) when measuring possible pullbacks. If you couldn’t find these numbers when looking at the Fibonacci sequence—you wouldn’t be alone.

These ratios are drawn from another mathematical constant, the Golden Ratio Φ (also golden mean, golden section or divine proportion). How are these numbers connected?

# On Earth’s Cracks and Crevasses

Earth Day is a wonderful time for reflecting on our planet. In today’s post I wanted to avoid the temptation to simply post a picture of Earthrise, a momentous vista which showed us our fragile planet for the very first time from lunar orbit. Instead, I’ve taken a look at some of the Earth’s cracks and crevasses as seen by NASA’s Terra satellite. Continue reading