Is a domestic windmill possible

My calculations:

Small scale Wind Power: A calculation

Power Output =>

where P = power in watts,

α = an efficiency factor determined by the design of the turbine,

ρ = mass density of air,

r = radius of the wind turbine,

v = velocity of the air

As an example given on wikipedia (http://en.wikipedia.org/wiki/Wind_turbine), for the following typical values,

α = 0.59 or less (Betz' law)

ρ = 1.225 kilograms per cubic metre at 15 °C

r = 100 metre (diameter)

v = 28.8 km/h

the power output P can be around 1.5 MW

Now in typical Bnagalore conditions, the values for a domestic turbine are

α = 0.59 or less (Betz' law) (same)

ρ = 1.204 kilograms per cubic metre at 20°C (calculations done at 1.165 kilograms per cubic metre at 30 °C )

r = 1 metre

v = 10 km/h (source google weather)

and the power is  = (1.5 MW) * (ρ2/ρ1) * (r2/r1)² * (v2/v1)³

= (1.5MW) * (1.165) * (1/100)² * (10/28.8)³

= 6.4 Watts approx

Also, the efficiency factor can go further down, and at an efficiency of say 30% we get almost 3 watt.

So to make it feasible - giving almost 60 Watt power, which is 20 times, either the diameter should be increased to almost upto 4.5 ()times - upto 4.5 metre or may be expect the wind to blow almost 2.7 (cube root of 20) times faster (at maybe 30 Km/hr), or a combination of both.

The first proposition is not actually good for domestic users with little or no roof space. The second can work in lot of coastal areas. The third can be worked out :)

A seach engine's death!

Look at this: torrentspy.

The search engine for torrents had to shut down. Forever.

But the ghost is still being chased. The Motion Pictures Association of America had filed a lawsuit against the company in Feb 2006 for "facilitating" copyright infringement. Yesterday, the US federal courts ordered a the torrentspy to pay some 110 million dollors to the association. News and Views:1,2,3 and wikipedia

The Zen of Python

Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren't special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch.
Now is better than never.
Although never is often better than *right* now.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea -- let's do more of those! (source)

So much philosophy behind a computer-programming language?
Well, yes! The programs in python do follow the above aphorisms.
I can vouch for at least the highlighted ones.

Cisco's Telepresence

Watch This:
http://www.youtube.com/watch?v=rcfNC_x0VvE

This is Cisco's telepresence magic !

What it appears like: DeBeer in US, Chambers in India, but both appear on a stage, together, (in India), and both are talking-laughing-discussing-every thing except shaking hands.

What they want us to believe: Cisco has discovered magic. Something like a sci-fi virtual reality movie.

What we guess: Perhaps they have discovered some 3D projection technology which they are using to duplicate the 3D video data they are capturing from a remote location and sending through high bandwidth channels. Not for everyone right now, only the corporate biggies are going to use it, but the technology is here.

The reality: Look at this wikipedia page. Cisco's Telepresence "...provides high-definition 1080p video, spatial audio, and a setup designed to link two physically separated rooms so they resemble a single conference room ...". Also, " ..The setup for the system include special tables, microphones, speakers, cameras, and lighting ..."

So how is the 'innovation' Chambers is so loud about (star trek and all) any different from a normal video-conferencing apparatus? The video quality is superior (1080p high-definition), agreed, but not the best available in market. 2K/4K digital cinema technology is commercially available, and ultra-high definition video is in the research phase (the comparison). And the sound? We already use lifelike sound in many of our electronic appliances. And then the lights-camera-action (and tables), are what a technology company should claim to be so proud about? Does it not look like just an assembly of high-performing products, already available in market, garnished with a disgustingly fake marketing campaign (which includes this video)? Bollywood song-choreographers can do it better.

And not to forget the price tag - $249000 - close to a crore rupees.

The product itself is pretty honest about its capabilities, but what makes it look flimsy-shallow is the way Mr Chambers chose to present it in India, as shown in the video.

3D printing

This (1,2) is really exciting.

Not only can this printer 'print' three dimensional objects, it is also capable of creating its own parts. Vik Olliver, the person behind the project, calls it REP-RAP (Replicating Rapid-prototyper), and aims to build a machine that can copy itself.

The major highlights of the project are self replication and GPL licensing.

The technology for 3-D printing exists and this uses one of them (Rapid Prototyping technology-Fused deposition modeling). It involves depositing layers of plastic to create 3-D models. But not only is the technology still more in research labs than tech markets, it it deemed to be very costly (a typical figure, provided by Olliver himself is some 30,000 euros). But Rep-Rap, he claims, should be affordable enough even for the developing world, where the material costs should be about 400 euros.

And the other feature that makes is affordable is the 'open' nature. So the design of Rep-Rap will be freely available under the GPL license. So anyone who can afford the material, and can invest the effort to use it or improve it, can do it. (One more condition- he should follow the GPL and keep his innovation also open)

It really good to imagine what all can be done if one such handy-robust-inexpensive machine is available that will make 3D objects for everything we can design on the computer. While most of it is expected to be models-prototypes, but a lot more can be imagined within the current constraints - toys, electronic circuits, showpieces and a lot of household stuff. Add more technology to this, for example, 3d printing with customizable material attributes - hardness, elasticity, conductivity, heat resistance. And then composites prints of various materials with varying attributes. All this and you are making almost everything that is being manufactured industrially.

Revolutionary!

Also interesting are Olliver's comments when he says - "We make no apology for this - as any biologist will appreciate, having the machine copy itself is the most useful possible thing we can make it do, and is the primary goal of the whole project" and this - "lmost all these were done by Vik Olliver, who clearly takes advantage of the 48-hour days they have south of the equator..."
Olliver works for CatalystIT, a Wellington-based open-source business system provider. He used his 'Google Time' he gets from his company for this, which means he is allowed to work on his own research projects one day a week.

Destroy the earth

This article lists 10 funny but possible ways to destroy the earth. The earth, not just the world or human race. Scatter it into crumbles. The one I found most interesting ranked No. 2.

You will need: a single von Neumann machine

Method: A von Neumann machine is any device that is capable of creating an exact copy of itself given nothing but the necessary raw materials. Create one of these that subsists almost entirely on iron, magnesium, aluminum and silicon, the major elements found in Earth's mantle and core. It doesn't matter how big it is as long as it can reproduce itself exactly in any period of time. Release it into the ground under the Earth's crust and allow it to fend for itself. Watch and wait as it creates a second von Neumann machine, then they create two more, then they create four more. As the population of machines doubles repeatedly, the planet Earth will, terrifyingly soon, be entirely eaten up and turned into a swarm of potentially sextillions of machines. Technically your objective would now be complete - no more Earth - but if you want to be thorough then you can command your VNMs to hurl themselves, along with any remaining trace elements, into the Sun. This hurling would have to be achieved using rocket propulsion of some sort, so be sure to include this in your design.
So crazy it might just work.
Earth's final resting place: the bodies of the VNMs themselves, then a small lump of iron sinking into the Sun.
Earliest feasible completion date: Potentially 2045-2050, or even earlier.
Source: "2010: Odyssey Two," by Arthur C. Clarke

Notice the source. The great Arthur C. Clarke, who passed away yesterday, perhaps out to begin another Odessey.

So VNMs are machines that are capable of producing another VNM. Can a human being be one VNM ? Perhaps no. The VNM is not supposed to die. Then, the virus? Doesn't die but is capable of reproducing. ( Well, that's also a debate). How about amoeba? It reproduces in a very interesting way - binary fission. At some point of time, (when it feels like) the single cell organism just divides into two cells, two independent organisms. So as long as it gets its food, it can continue this process, and some day consume the entire raw material source - the earth. But all the silicon and magnesium and iron may not be edible. So as long as they don't get adapted to this kind of diet, the earth seems to be safe from them.
But lets cross-examine that assumption of death. Why is the VNM not supposed to die? It can very well die and be the Frankenstein it is supposed to be as long as the rate of creation is greater than the rate of death. And that can be assured in the design phase itself. Or maybe the version 2 of such machines can be made adaptable to their limiting factors - lack of raw materials etc. They can be made to have a science of themselves.
Just like us the human beings. We are fast working towards ensuring that our rate of survival is greater than the rate of death, that we can make best exploitation of the resources. We sure will win one day discovering newer ways of using all the silicon-iron-magnesium that there is in a process that outputs more of our kind.We will win against disease, death and war, and will become the VNMs ourselves.
All this even if we put no efforts in building the VNM.
(Also look at the time-line Clarke suggested.)

ZFS

The ZFS comes into picture straight from the Sun-NetApp Lawsuit.

The wikipedia page for ZFS states lots of big-mouthed appreciation for the file system. Look at this - " ... Project leader Bonwick said, "Populating 128-bit file systems would exceed the quantum limits of earth-based storage. You couldn't fill a 128-bit storage pool without boiling the oceans. "

And also this -
" Although we'd all like Moore's Law to continue forever, quantum mechanics imposes some fundamental limits on the computation rate and information capacity of any physical device. In particular, it has been shown that 1 kilogram of matter confined to 1 liter of space can perform at most 1051 operations per second on at most 1031 bits of information [see Seth Lloyd, "Ultimate physical limits to computation." Nature 406, 1047-1054 (2000)]. A fully populated 128-bit storage pool would contain 2128 blocks = 2137 bytes = 2140 bits; therefore the minimum mass required to hold the bits would be (2140 bits) / (1031 bits/kg) = 136 billion kg. To operate at the 1031 bits/kg limit, however, the entire mass of the computer must be in the form of pure energy. By E=mc², the rest energy of 136 billion kg is 1.2x1028 J. The mass of the oceans is about 1.4x1021 kg. It takes about 4,000 J to raise the temperature of 1 kg of water by 1 degree Celsius, and thus about 400,000 J to heat 1 kg of water from freezing to boiling. The latent heat of vaporization adds another 2 million J/kg. Thus the energy required to boil the oceans is about 2.4x106 J/kg * 1.4x1021 kg = 3.4x1027 J. Thus, fully populating a 128-bit storage pool would, literally, require more energy than boiling the oceans

"

Path-breaking ? Revolutionary ? Not really. Big words. Big figures. Marketing.

HP laptops

HP PSG is doing really well.

Not that HP laptops are new entrants to the market normally dominated by Dell, Lenovo, Sony or Apple (in different segments). They had existed, even when no one was talking about them.

So is this a breakthrough in technology? Or maybe low cost push? Perhaps not both. So HP laptops are not as innovative as the Macbook, not as stylish may be as a Vaio, don't have the an as strong internet sales backbone as Dell, and are technology wise, at most equal to the Lenovo. They have never been far behind the other products, but they perhaps lacked the glamor the competitor brands have been able to associate with themselves. So if you own a Viao, you own a luxury, and if its an HP, its a laptop computer ! Just a laptop.

But something changed. At some point the PSG decided to project itself to the market. It already enjoyed the convenience that it owns an identity. It is surely recognized as a decent technology vendor with reliable customer support and reasonable prices. People know the name. They had to be persuaded to push their pockets for this name.

Look at this and see how this is being done.
Look at the way they are building the HP brand. Look at " The computer is personal again" campaign. The flamboyance with which the company has dared to present itself in the aggressive ad campaign is what is responsible for the niche that it has now carved for its products. So when I HP ads all around, i can hear them say, 'buy our stuff, its cool'.
And no surprises, PSG (which is the part of HP dealing in laptops and desktops) is a $40 billion company.

query compilation

It was difficult initially to accept that sql queries are compiled.

What had made strong impressions on my mind was the assumption that the queries could be treated just like commands, like shell commands. Commands that need good amount of parsing may be. The pre-compiled procedure for executing the query might be doing the job well enough. [And having 'language' in the name doesn't qualify it for compilation]

A friend told me that queries need to be compiled because of the optimization thats necessary. Where does optimization entail the need for compilation? A detailed discussion let me through.

Say if we have a query containing a join of tables T1, T2 and T3. If you go by executing it the way i thought it would (close to interpreting), it goes as (T1 join T2) join T3. But in sql querying, lot of optimization can be achieved by simply reordering the joins. So T1 join (T2 joint3) may be a better execution strategy. That can only be done if the process executing the query, passes through the entire query statement, once or more to find optimization opportunities like this, and develop a plan for executing it. And this is very close to what a compiler does. :)

The need for query optimizations can be understood from what Dr. Umesh Dayal (HP Fellow) talks about business intelligence. "... in business intelligence scenarios, you are typically faced with queries that are very large ... the largest ones you might have written may be around five pages in length (me ?? five lines!) ... but here we 're talking about queries normally running into twenty pages ...". Imagine what optimization-less querying can cause to a database.

Thanks to my sql-mx friends who made me realize that.