Wiki Christmas

Everybody in my family makes Christmas lists and then people buy things on those lists, but nobody who wants to buy things knows what the others are bought so far. For a procrastinator like me, this is an undesirable situation because I don't want to waste time bringing things back to the store in case somebody else has already bought it.

There ought to be some sort of website where people can go to make a Christmas list and then others can view it and if they purchase something on the list, they can flag that gift idea. The person who made the list wouldn't know, but any other people viewing the list would be able to see that that gift was taken already.

I hope that this is already invented somewhere in the vast reaches of the internet, and if it isn't, maybe I'll get around to it sometime.

UPDATE: There is such a tool!

Minimizing Memorization App Prototype

I've produced a prototype page to allow people to use my minimizing memorization calculator with more ease.

Prototype

Just enter the data as the form requests and click calculate! If you try different values for how many answers you know well, then you can figure out how little you actually have to learn to get the mark you want.

This is the url: http://doless.9k.com/

The calculator tells you the chance of getting at least a certain number right. The math works as I've described in my other post called "Minimizing Memorization."

Sorry for the ads on the calculator's page, they came with the free hosting!

If you have any comments about how I might improve the calculator, please leave them on this post.

UPDATE: The calculator is working well for all values which are not too big to overflow the variables. If that's the case, you'll get NaN% as your answer. That just means that I can't help you for that scenario. I'll try to figure out how to improve the range over time.

A death in the family

My computer monitor was tragically destroyed on the way back home.

I made this meme in its memory.

Applet for minimizing memorization

I've been talking to some friends who are far more skilled at programming than I to figure out how to make an applet for the minimizing memorization formula. I know that most people are not as enthusiastic about math as I am, so I want to have a nice GUI where users can enter how many questions are on the exam, how much material is examinable, how many questions they have to choose and what mark they want to get. Then it will just spit out the probability based on a certain amount of studying. Nice and simple... (and I want it to be free).

A good friend of mine created Cold Turkey, which I thought was pretty cool so I asked him what to do to make a GUI. He recommended Java Script, so I'm checking that out now. I'm looking for an easy WYSIWYG Java Script internet thing.

Directional Coupler

This is one of the circuits that my lab partner, Jessup, and I built in the microwave lab this year. It's a directional coupler. The lab tech spelled my name wrong (lol):

Money Tree

Last January, I decided that I wanted to grow a tree. I bought a small one from Loblaws and I've been meaning to track its growth. I want to study it but I don't really know how to begin. I've always wondered why certain branches have five leaves, others have six but others still have only four.

I wish there was a way to open up the genetic source code and see what's going on in there. I want to design my own plant from scratch. Maybe some day that will be possible; or maybe it already is and I don't know it. I watched an interesting TED lecture about Craig Venter and his colleagues creating synthetic life. Imagine the possibilities. What if we could create plants to do our bidding or to interact with damaged ecosystems? Maybe we can make new fruits and vegetables that are more efficient or delicious (whichever you prefer).

When I leave university, I suspect I will grow more trees. I find them fascinating.

Minimizing memorization

In third year, I was forced to take Organizational Behavior. There were more than 150 definitions that we were supposed to memorize for the exam. You won't find many people who enjoy memorizing definitions on a Friday night less than me.

On the exam we were going to have a choice of questions: e.g. you would have to choose, say, 10 of 20 definitions. The problem then, was this: how do I memorize the least amount of useless knowledge and still do well on the exam?

I thought about the problem for a while and decided that it was like a game of Keno in a casino.

In Keno there are 80 balls which are numbered 1 through 80. The player chooses 20 numbers and hopes that many of them or none of them will match the 20 numbers randomly chosen by the casino. The odds of choosing all 20 correctly are ridiculously small and the chances of choosing 0 are also very small. It makes sense that some of the numbers you choose will show up, and some won't.

For example, if I choose 20 numbers, then the casino chooses 20 numbers randomly from the 80 available. The chance that I will have chosen 5 numbers that are the same as what the casino chose is 23.3%. By contrast, the chance that I chose 0 correctly is 0.119%. The chance of choosing all 20 correctly is 1 in 3,535,316,142,212,173,800 (or basically zero).

Anyway, the point is that we can use this Keno game to reduce the amount of memorization that we have to do for a test.

Let's say that there are 20 questions, like on my Organizational Behavior exam. I only have to choose 10 questions. The questions are basically "what does this word mean," so you just have to memorize the answer.

We can think of this like a game of Keno. There are some number of total definitions that could be on the exam. For example, in my OB course, there were about 150 definitions. This is like the total amount of numbers in Keno.

Then we need to know how many answers we want to get right. Let's say that I want to do fairly well and I want to get 8 out of 10 right.

In a game of Keno, with 80 numbers and a player choosing 20 numbers, the chance that k of the n numbers chosen by the player match the 20 chosen by the casino is:

Odds in Keno

To generalize this formula to suit our problem, we just change the 80 to be the number of definitions that could be on the exam (i.e. all the stuff you learned in the course). Then n is the number of definitions that I memorized and k is how many I want to get right. We replace the 20 with the number of questions that actually are on the exam.

If we want to get at least a certain mark, like at least 50%, then we add up all of the probabilities above and including that k value.

Then the formula becomes:

Let's use this formula for my upcoming mandatory history course exam. I can say that there are 15 main topics in the course that might have "short answer" questions. On the exam, there will be 10 "short answer" questions and I will have to choose 4 of them. I want to get all 4 right, of course. How much stuff can I avoid learning and still have a 90% chance of getting 4 out of 4?

I try subbing in different values for answersKnown and I find that if I know a lot about seven out of fifteen topics, I will have a 90.0% chance of being able to answer at least four out of the ten questions that will end up on the exam. Since I only need to choose 4, I don't care if I can't answer all ten or even five of ten.

It's interesting to see how much extra work increases the chance that I'll get all four questions. If I know 8 things, I have a 98.1% chance of getting four out of four. Clearly, there is no point in learning any more than just over half of the material in the course for this section of the exam.

It's interesting to note that the chance that I'll be able to answer four questions drops off very quickly. If I know only 5 or 6 things, the chances are 43.4% and 71.3%, respectively.

Criticisms
If you can find a problem with my formula or any flaws in my reasoning, please leave a comment so that I can fix it!

I used the formula to minimize the amount I had to learn in third year Organizational Behavior and ended up with a 94% in the course. (which is also the minimum mark to qualify for an A+) But this doesn't prove that it works! Maybe I just got lucky.

Remember, study smart, not hard!

The Limits to Growth

I'm reading the Maze of Ingenuity by Arnold Pacey for my obligatory history course on the impact of technology on society. For once, the reading is about something besides how many widgets Britain manufactured in 16-oh-don't-care or how many people died in such and such a kerfuffle over such and such a piece of land.

The reading is about the future of our development as a species. It is an intrinsic part of us to want to learn new things about our universe. Even as far back as 1851, when there was concern over the direction and ultimate sustainability of human progress, critics were romanticized by the possibilities of scientific advancement. While Babbage wrote about the 'inevitable' exhaustion of Britain's coal reserves and Jevons criticized unsustainable exponential growth, they were each optimistic about the steady march of science.

I can certainly understand their perspectives, living in a world addicted to the oil barrel which must eventually run dry. Luckily for us, although Babbage was right, his predictions did not come to pass. Coal was replaced by other sources of energy and the exponential growth that supported his argument stagnated and declined (in coal). The problem has been delayed, not solved: like a cardiac patient switching to a new brand of bacon bits.

I'm sure that every generation finds something to worry about, which to them, could end the world and destroy humanity. Eventually, one of us will be right about that. In order to avoid that lucky generation from being us, or our children or our grandchildren, we need to redefine 'progress' and find smarter ways to fuel its growth.

In the book, the author suggests that progress be related to human welfare, which seems obvious, but certainly isn't the case in most places (including this one). I'm not suggesting that it's an easy thing to change the culture of entire nations, but it's happened before. We need better technological goals that are focused on better lives rather than better toys.

I would argue that there is hope and that we can see that happening in our societies, albeit slowly. Our economies are becoming more focused on services, which rely on the most renewable of all resources -- human creativity and labor.

The other half of the equation is the energy that we use to fuel everything that our lives require. That's where I hope to come in some day. I feel a duty to work towards making renewable energies cost competitive. Once they are, then their time will have come and no rational person will be able to say no. We can begin to see that happening for wind power. Solar is still a way off, but it's getting better rapidly.

Anyone who has ever tried to build something will tell you that solutions usually cause new problems. I'm excited to see if we can be clever enough to invent solutions to the problems presented by our previous solutions.

Small is Beautiful

I read an interesting quote from the book Small Is Beautiful: Economics As If People Mattered:

"A Buddhist economist would consider this approach excessively irrational: since consumption is merely a means to human well-being, the aim should be to obtain the maximum of well-being with the minimum of consumption.... The less toil there is, the more time and strength is left for artistic creativity. Modern economics, on the other hand, considers consumption to be the sole end and purpose of all economic activity."

The author is referring to the current economic paradigm of endless growth.

Artistic creativity is a good reason to value one's own time. If I have $20, then I can use it to buy stuff that I'll get bored of eventually, or I can use it to not work for some period of time so that I can be artistic and play. That's why I love the internet -- being artistic there is free.

I'm trying to find this book so that I can read more. There will be many interesting problems that arise in the future because of our dwindling resources. They will be challenging because they will be so multidisciplinary and will challenge our "business as usual" economic models and culture.

I'm excited to see if our economic model of infinite growth changes in the future. Of course, it will have to eventually because there aren't infinite resources anywhere. How long can it go on? Changing culture is never easy.

Note to self: Read Small is Beautiful (I have a bad memory)

Minecraft Conveyer Belt

I like designing circuitry in Minecraft because it makes my degree actually seem useful while I'm in school. Recently, I built a device that brings a block from one point to another automatically. It can be used to ferry ore from a mine to a city, for example.

Until recently, I was a Youtube noob and had never made a Youtube video. I decided that I didn't want to be a noob anymore so I made a crappy video of the conveyer belt.

You can now download a map containing the conveyor belt to learn how to build it.

Linear Quadratic Regulation

I'm working on my 4th year project in electrical engineering and we are designing an autopilot for a Quadrotor. So far we've used PID controllers to try and control the beast. Luckily, MATLAB has a nifty function to tune PID controllers for you. Unluckily, that function doesn't work for one of our mathematical models. I'm not sure why, but it's definitely busted.

Long story short, I have to learn about some other method of tuning that isn't "automatic" (i.e. it's gonna be manual and manual means a lot more painful mathematically). I'm hoping that Linear Quadratic Regulation will be my golden ticket to not failing my project.

I'm reading a document about it now. Hopefully describing it here will ensure that I actually understand what I'm reading and it doesn't just get dumped out of my brain.

For those of you who haven't heard of a Quadrotor, this is a fine specimen. Ours actually has a giant bubble around it to prevent it from getting too injured when we inevitably crash.

The controller will adjust the individual rotor speeds to determine which way the Quadrotor flies. The craft determines where it is in space from 16 cameras that we have set up around the room. They give it (x,y,z). Then we tell it where to go and it goes there (in theory at least).

Mathematical Biology

Mathematical biology! After having read about mathematical biology in a Wikipedia article, I couldn't sleep last night. I kept thinking about how you might model plant growth or how plant photosynthesis could be used to generate energy.

I was googling for a free text book on the subject to sate my curiosity when I found this link: http://spot.colorado.edu/~dubin/bookmarks/b/1240.html

There was a textbook there from the Hong Kong University of Science and Technology. The author goes through many mathematical derivations, but he takes the time to apply it to living things.

He wrote about Phi, the golden ratio and how it could be seen in a sunflower. phi is the ratio between consecutive Fibonacci numbers as n goes to infinity.

Grow cell, turn, grow cell turn, etc. But how much of a rotation should you perform for each step? The pattern is made most efficient with a certain amount of turning. One of the greatest beauties of nature is that evolution solves mathematical problems on its own over time. The sunflower contains the best solution to the problem. The link has a little app that lets you try different rotation values and it builds a sunflower based on them. It turns out that Phi (1.61803...) is the best solution.

The golden ratio exists all over nature because the optimal growth solution has evolved over time. That's pretty amazing.


This all makes me think that the Fibonacci sequence might lead to some interesting Minecraft designs...

Why?

I've created this blog to enable future versions of me (and perhaps you) to look back and know what past versions of me were thinking.