Tag Archives: mathematics

Terrible advice from a great scientist

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Darwin is Wilson’s Bill Gates, his outlier from which he draws general conclusions. However, even Darwin himself wrote:

I have deeply regretted that I did not proceed far enough at least to understand something of the great leading principles of mathematics;  for men thus endowed seem to have an extra sense.

It is this extra sense that makes math such a powerful asset to biological thinking. Indeed “thorough, well-organized knowledge of all that is known or can be imagined of real entities and processes within that fragment of existence.” requires math to chart and define these “processes” as processes in the first place

via Terrible advice from a great scientist | Byte Size Biology.

Throwing and catching an inverted pendulum

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Armed with a good theoretical model and knowledge of its strengths and limitations, the researchers set out on a process of engineering the complete system of balancing, throwing, catching, and re-balancing the pendulum. This involved leveraging the theoretic insights on the problem’s key design parameters to adapt the physical system. For example, they equipped both quadrocopters with a 12cm plate that could hold the pendulum while balancing and developed shock absorbers to add at the pendulum’s tips.

via Video: Throwing and catching an inverted pendulum – with quadrocopters | Robohub.

Below is the Youtube video.

More info at the Flying Machine Arena.

The Flying Machine Arena (FMA) is a portable space devoted to autonomous flight. Measuring up to 10 x 10 x 10 meters, it consists of a high-precision motion capture system, a wireless communication network, and custom software executing sophisticated algorithms for estimation and control.

What the Dalai Lama can teach us about temperatures below absolute zero

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Here’s the new definition that they came up with. Temperature measures the willingness of an object to give up energy. Actually, I lied. This isn’t how they really define temperature, because physicists speak math, not english. They define it as \frac{1}{T} = \frac{dS}{dE} which says, in words, that the temperature is inversely proportional to the slope of the entropy vs. energy curve.

via What the Dalai Lama can teach us about temperatures below absolute zero | Empirical Zeal.

Theresa Christy of Otis Elevator: Making Elevators Go

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Here is a typical problem: A passenger on the sixth floor wants to descend. The closest car is on the seventh floor, but it already has three riders and has made two stops. Is it the right choice to make that car stop again? That would be the best result for the sixth-floor passenger, but it would make the other people’s rides longer.

via Theresa Christy of Otis Elevator: Making Elevators Go | Creating – WSJ.com.

Halving day is almost upon us!

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Bitcoin is built so that this reward is halved every 210,000 blocks solved.  The idea is as bitcoin grows the transaction fee’s become the main part of the reward and the introduction of new bitcoin’s slows down to a trickle.  This also means that there will only ever be 21,000,000 bitcoins in circulation.

Well, in less than 4 days the block count will reach the first of these 210,000 block milestones and the reward for solving a Bitcoin block will half from 50BTC to 25BTC. (Have a look at bitcoinclock.com)

via Halving day is almost upon us! | Mineforeman.

Obama Wins: How Chicago’s Data-Driven Campaign Triumphed

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For all the praise Obama’s team won in 2008 for its high-tech wizardry, its success masked a huge weakness: too many databases. Back then, volunteers making phone calls through the Obama website were working off lists that differed from the lists used by callers in the campaign office. Get-out-the-vote lists were never reconciled with fundraising lists.

via Obama Wins: How Chicago’s Data-Driven Campaign Triumphed | TIME.com.

The new megafile didn’t just tell the campaign how to find voters and get their attention; it also allowed the number crunchers to run tests predicting which types of people would be persuaded by certain kinds of appeals.

A Bandwidth Breakthrough

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Testing the system on Wi-Fi networks at MIT, where 2 percent of packets are typically lost, Medard’s group found that a normal bandwidth of one megabit per second was boosted to 16 megabits per second. In a circumstance where losses were 5 percent—common on a fast-moving train—the method boosted bandwidth from 0.5 megabits per second to 13.5 megabits per second. In a situation with zero losses, there was little if any benefit, but loss-free wireless scenarios are rare.

via A Bandwidth Breakthrough – Technology Review.

The technology transforms the way packets of data are sent. Instead of sending packets, it sends algebraic equations that describe series of packets. So if a packet goes missing, instead of asking the network to resend it, the receiving device can solve for the missing one itself. Since the equations involved are simple and linear, the processing load on a phone, router, or base station is negligible, Medard says.

Recycled photons set fresh quantum computing record

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Laing’s team is also working towards that end. As part of the recycling technique, the researchers chained together two logic gates – a first for an optical quantum computer and an essential step in terms of hardware for building more complex devices. “To me, this achievement is more important than factoring 21, although to do so is an excellent demonstration of the technique’s power,” says Browne.

via Recycled photons set fresh quantum computing record – physics-math – 23 October 2012 – New Scientist.

A group of Finnish math teachers write an open textbook in a weekend hackathon

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A group of Finnish mathematics researchers, teachers and students write an upper secondary mathematics textbook in a booksprint. The event started on Friday 28th September at 9:00 (GMT+3) and the book will be (hopefully) ready on Sunday evening. The book is written in Finnish.

via Vesa Linja-ahon blogi: A group of Finnish math teachers write an open textbook in a weekend hackathon.

Quantum cryptography: yesterday, today, and tomorrow

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Imagine you have a product of two prime numbers, say, 221. Now, we set that number to be an endpoint—for the purposes of our game, there are no higher integers. If we multiply two numbers together and get a number larger than 221, it wraps around, so 15 times 15 results in 225-221 = 4. If we multiply two by itself, we only get four, which doesn’t wrap, and we can do that 7 times before it wraps. But 28 results in 35. Got that? Great.

via Quantum cryptography: yesterday, today, and tomorrow | Ars Technica.

Let’s consider a consequence of using phase to calculate prime factors: 221 has prime factors 17 and 13, and factors 1 and 221. We can eliminate the latter in the classical part of our algorithm. But, what about two and 111? “Wait,” you say. “That is not a factor. The product is 222.” Nevertheless, we need to think about it, because quantum algorithms are probabilistic. 17 and 13 have the highest probabilities, but two and 111 only have a phase error of 0.5 percent. The probability of Shor’s algorithm returning the incorrect result is rather high. Unfortunately, a near miss (though easy to spot, since it is very quick to calculate that 2×111=222 not 221). This is likely not very useful in terms of decrypting a message, so we need to do something to increase the chance of getting the correct answer.