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Those of you who love Reverse Polish Notation as much as I do will really love this new fashionable notation, which is even more indulgent: Arithmetic Tree Notation. Consider, for example, a "human readable" mathematical expression: |
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Most modern compilers solve the ambiguity here by defining a sensible order of operations. RPN takes a different approach by using stack order evaluation, in effect making everything upside-down, backwards, and retarded: |
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True nerds enjoy this sort of obfuscation, because it helps differentiate the nerdy elite from math-ignorant commoners. But when RPN calculators were introduced into public schools, all sorts of people started learning the notation, and now it's no longer a badge of honor. |
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To remedy this, and to prevent this situation from claiming a perfectly obscure notation again in the future, clearly we need a notation too difficult for kids. So the most important design question in developing a new notation is: what other data structures could be used to make schoolchildren cry? The answer: a binary tree. |
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Arithmetic Trees are binary trees wherein branch nodes are operators and leaf nodes are operands. The tree is notated row-wise top-to-bottom and left-to-right. So a simple graph like the following: |
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Finally, a sensible but terrifying notation! Only true nerd royalty would dare to use it. Unfortunately, evaluating this expression is more computationally expensive than RPN, but that's a small price to pay for the pride that you'll feel when using the newest and hottest arithmetic notation. |
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Four-hour continuous chunks of college-classes can grow monotonous, and I usually find myself drifting off and thinking about strange things. Sometimes it's the math problem that was due twenty minutes ago, sometimes it's that redhead in the third row, and sometimes it's techno-gadget stuff that I wish someone would actually build (and then give to me, free of charge).
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Lately I've been thinking about wireless-izing everything, and think it sucks that I can talk on my cell phone without wires, but I have to plug it in to charge it.
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You get home, hang up your coat, and put your cell down on the table, and it will automatically charge without you doing anything.
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I propose a quick-and-easy system consisting of two nodes:
- Grid of Lasers (base station)
- Photovoltaic cells (inside phone)
- Optic receptors (base station)
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The grid of lasers lives in a table, each focused towards the ceiling, below a glass tabletop. The photovoltaic cells (solar cells) live behind the LCD screen in the phone. The optic receptors live in the table and will sense the phone, when placed screen-down, and activate the correct lasers to start charging.
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Current technology is not capable of supporting such an idea, but the numbers are within limits, if money is no option. First, consider the phone. Mine takes about 2 Watts, and takes less than an hour to charge fully. Existing class 3a lasers (like the ones you would find in laser pointers) are probably not only output 1-5 mW.
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The next step up are class 3b lasers, that operate around 5-500 mW. These are generally not fire hazards, unless you focus more than 1 W of power within a 1 cm2 area. Fortunately, my cell has a screen of about 6 cm2. So four of Latronix's Reliant Argon 300WC Argon Lasers would probably do the trick, while not seeting anything on fire.
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Unfortunately, these are big lasers, so it's not possible to really cover the entire desk with them. Alternately, it's possible to coat the desk with angled LCD-mirrors that become translucent when not recieving energy. This way, we turn on three of these mirrors to focus these lasers anywhere on the desk. Let's say the phone is at coordintes (x, y) on the desk, then we turn on:
- x-direction mirror at (0, 0) - light now is travelling either north or south towards the phone.
- y-direction mirror at (0, y) - light now is travelling either east or west towards the phone.
- z-direction mirror at (x, y) - light now is travelling towards the ceiling, hopefully hitting the phone, instead of someone's eye, or a stack of papers.
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So four lasers at 300 mW a piece equals 1.2 W, and given that existing photovoltaic efficiency of about 33% (this is conservative given the focused nature of the lasers), the energy arriving at the phone is about 400 mW. Given this plan, my phone would take about five hours to fully charge. Hey, if you need it charged sooner, plug it in.
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The specfications on the optic receptors are a little more sketchy. Conceivably, the desk could act like a touch-screen monitor. When it senses something with the outline of a cell phone, it sends a short pulse of white light towards the screen to determine the color, and if it matches the green-brownish gray of the screen, it starts to charge.
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Safety measures can be built in by having the desk chime before charging, at which time the owner must respond verbally (or accoustically, as with the Clapper).
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Most of these prices are rough (and liberal) guesses, because most places that sell this stuff don't actually put the damned prices on the damned site:
- Four Latronix Lasers = 4 x $2000 = $8000
- About four thousands LCD mirrors (1 cm2) = 4000 x $6 = $24000
- Touch-screen monitor technology for 40x100 cm desk ~= $1500
- Computer to determine location of phone ~= $100
- Various wires, building materials ~= $2000
- Power to light four lasers for five hours = 20 A x 208 V x 5 hr x 0.01 $/kw-hr = 21 kw-hr x 0.16 $/hw-hr = $3.36
- Grand total = $35,600
- Monthly total (16 phone-charges/month) = $53.76
- Being a little bit more lazy = priceless
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As phones become more energy-efficient, photovoltaic cells become more efficient, and people think of better ideas than the 4000-mirrors idea, the price of such a table could come down to less than $10,000. By far, though, the better idea is to have the bottom of the phone be a contact for charging, and have current flow through the table only to where the phone is located, a solution which could probably be worked down to the sub-$1000 range.
Either way, given the price, the phone would probably be included with the purchase of the table.
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This page best viewed while dangerously intoxicated.
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codythefreak.net, or c7f.net is not copyrighted, reserved, limited, restricted, or private. Information is always inherently free.
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If I don't want you to read, view, or plagarize something, I won't post it up. Courtesy appreciated 2001-2006.
Up 222 days, 21:51.
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