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How to sort rated content
29 lug
If you are a web developer, or at least a webmaster, and if you have rateable content on your website, you probably almost once faced this common problem: how should I sort my content, using the collected rating data?
As a common problem, it has common but different solutions, most of which are wrong. We will analyse two cases: the up/down rating, and the 5-star rating.
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Mastering the Ackermann Function
29 lug
Yesterday I came in touch with a curious, astonishing mathematical function. It’s called Ackermann function.
Mathematically speaking, it is a well-defined total function. That is, it has defined values for every integer input (= total function), and this value is not ambiguous (every input has one and one only possible output value) (= well-defined).
Speaking about computer science, this function is computable, but it’s not a primitive recursive function. In other words, you can implement an algorithm to express the function using while-loops (= computable), but still you cannot write an equivalent algorithm using only do-loops (= not primitive recursive). I suggest you to try this statement.
The function has this form:
As you can see, it’s form is fairly simple. But, even if it seems simple, its values explode quickly. A(4, 2), for example, has more than 19.000 digits.
Representation of the Ackermann Function on the complex plane
What I want to talk about is the possible implementation of such a function by means of a computer algorithm. I will use Python for the next examples, but the description is language-independent.
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Apple updates the (Mobile) Apple Store
27 lug
It seems almost clear to me that Apple is betting on iOS and it future. Almost exclusively on iOS, I would say. And at the same time the old Apple “core business” is being left behind. Slowly.
Just look at the recent updates. iPhone OS 3.1.3 for iPhones and iPos Touch’s. Then iPad and the consequent iPhone OS 3.2. Then the new iPhone 4 and the developers’ beta preview of the new iOS 4. Then again a recent fix with iOS 4.0.1 and a preview of the next iOS 4.1. The mobile market seems to be a very profitable one. To the extent that Apple is betting everything on iOS and very little on Mac OS & Co. Let’s see why.
We can recognise this to be true if we carefully look at the Apple Store. All the recent updates are about:
- MacBook Pro
- Mac Mini
- iMac
- Mac Pro
- Apple Cinema Display
All the updates mainly interested internal hardware upgrade, with no significant updates to the product as a whole. Apple has always been late, speaking about the internal hardware of their products. Just think about Sony. They sell VAIO’s (I once owned one, will never go back to it) which cost almost half the cost of a MacBook and have almost twice-powerful hardware (speaking about internal CPU, GPU, RAM memory and HD bundles).
They are trying to get back on track. But even with the latest updates, Apple has just put a little redesign to the internal hardware configuration. Some new Core i3, i5 and i7 processors appear (about 8 months later than the competitors). Some new nVidia graphics card are replacing the older ones, but these models too are already old. A discrete nVidia 330M for a top line product as the MacBook Pro seems ridiculous to me. Yes, they made really big improvements to the MBP screen, introducing a new Hi-Res display for the 15″ model. A great move, I admit.
But the “packaging” is always the same, and the price has unexpectedly risen. Only the Mac Mini has gone through a complete redesign, to couple its design to that of the Apple TV. I prefer not to talk about it, since it is one of my greatest dreams, but since I’m in Italy I would pay 799 EUR for it (~ 1.049 USD) instead of 699 USD. Unbelievable.
The packaging is always the same, I just said. The MacBook Pro’s have not changed since the last year. The iMac has not changed since the last two years. Even the Mac Pro will not change. These products’ design could surely be improved, but Mother Apple is focusing on something completely different.
In this new touch-based world, they release the new Magic Trackpad. It’s cool. But useless, in my opinion: why would I use a trackpad when I’m using an iMac? That said, it surely will sell a lot.
And in this Apple-centric market, they release the new Battery Charger. Apple can sell you everything you need to play internet, music, videos and games. Everything.
They’re pushing through these new routes. They’re pushing through frequent iOS updates. Frequent mobile devices updates. Frequent complementary mobile devices introductions. But they are loosing grip on the whole Mac OS world.
I hope they do not abandon Mac OS in the middle of a road.
I still hope to withstand the miracle of a Mac OS XI.
I hope they will not convince me to do everything I am used to through an iPad.
At least, as long as they do not give me one for free.
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Follow the White *Rabbit* iPhone 4
23 lug
Apple has recently stated that they are experiencing difficulties in building and delivering the white iPhone 4 model, due to a problem (probably) related to the new front Gorilla Glass painting procedure.
The late-to-come white model is going to destroy people’s expectations, especially of those one who have waited till now just to buy this glamour model. We still do not know when will we be able to grab the white one, and probably we will not for a long time.
Once again, we have to wait for Apple to reveal when this delay will come to an end.
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Antennagate: Apple avoids the problem and loses in 5 moves
17 lug
Everyone should know, by now. The latest Apple creation, the astonishing new iPhone 4, has some really big issues. The main is certainly the so called “death-grip“: depending on how you hold the phone, it eventually loses signal and drops calls. As Apple said, “X marks the spot”, the spot being the little gap between two external antennas on the outer edge of the new iPhone.
I will try to demonstrate that Apple is avoiding the problem giving void answer and trying to pilot the customers’ and press opinion towards wrong concepts.
I will not post here the (really) many video demonstrating how you can make calls drop just using one finger, but I suggest you to search for them on YouTube. This is what actually happens: if you short-circuit the two antennas using your hand (or finger) the antenna reception gets weaker, signal drops from 5 or 4 bars to 1 or 0, and eventually the call drops.
To contain the “bad reputation” plague, the so called Antennagate, on July 2nd Apple has published an open letter addressing the problem. Apple said that they analyzed the problem and found the cause: the algorithm that calculates the bars is wrong! So, they promise they will address this issue and fix it in a software release. Yesterday the officially released the “fix” through iOS version 4.0.1. What a smart move: let the iPhone show an average lower number of bars, so that the signal now weakens from 4 or 3 bars to 2 or 1 (in the same conditons). Everyone in the world will now think to be in less covered areas and that the iPhone is not loosing so much signal.
But, in my opinion, the problem (which clearly is a hardware related bug) will remain. No software fix can solve a physical short-circuit. And, surely, even with iOS 4.0.1 calls will continue to drop.
Yesterday (July 16th) Apple has given a quick and not anticipated press conference to talk about these “rumors”. These where the guidelines (the 5 moves):
- Every smartphone has a weak spot
- AppleCare is receiving few calls from customers complaining about iPhone 4 reception problems
- iPhone 4 is dropping less than 1 more call every 100 calls related to the iPhone 3GS
- iPhone 4 customers are not bringing back the iPhone 4 to the Apple Store for a refund
- Free bumpers for everyone
Let’s analyze them one by one. As said, in my opinion Apple avoids the problem and loses in 5 moves.
1. Every smartphone has a weak spot
This is surely true. The antenna reception issue is a physical problem. Human hands and bodies have a strong capacity of absorbing microwaves, including those waves that give us connectivity. This problem is true for Apple, for Nokia, for RIM, for HTC, and for everyone else. Nothing to say about that.
You hold an Apple device, and signal weakens. You hold a Nokia device, and signal weakens. You hold a RIM device, and signal weakens. You hold an HTC device, and signal weakens. And so on. Steve Jobs has correctly addressed one of the problems.
Beside the fact that Nokia and RIM both have argued about Jobs’ decision of pulling them into the Antennagate tornado, Jobs has just demonstrated that every smartphone has an issue with reception. But not that every smartphone is constantly dropping calls when gripped. This is true for iPhone 4 (as seen on YouTube), but is it true for the others? Steve has not demonstrated it. And this (dropped calls) is the real issue.
2. AppleCare is receiving few call from customers complaining about iPhone 4 reception problems
3 millions iPhone 4′s sold in three weeks. That’s great. Kudos for Apple. Only 0,55% customers calling the AppleCare for complaining about reception problems. About 15,000 devices, I’d say. That number sound small. But, how many customers are going directly to Apple Stores to complain? How many customers are calling AT&T Customer Service to complain? Is that real that only 15,000 customers are so desperate to call the AppleCare service for complaining? I’m not that sure. AppleCare is just a slice of the whole pie.
3. iPhone 4 is dropping less than 1 more call every 100 calls related to the iPhone 3GS
Well Steve Jobs said this: for every 100 calls, iPhone 4 is dropping about less than 1 more call than an iPhone 3GS. But, we have no data about the iPhone 3GS, though.
Look at this example: let’s suppose that iPhone 3GS drops 0,05 calls every 100 calls, whereas iPhone 4 drops 1 call every 100 calls. Jobs is true when he says that iPhone 4 is dropping less than 1 more call every 100 calls. But is still true that the iPhone 4 is dropping an absolute 20 times more calls than an iPhone 3GS. Numbers are numbers, we cannot argue. So, Steve Jobs hasn’t really given us a real datum. We should know how many percent more calls iPhone 4 is dropping compared to the iPhone 3GS.
4. iPhone 4 customers are not bringing back the iPhone 4 to the Apple Store for a refund
Surely they initially will not. They will try to convince themselves that the problem still doesn’t exist. And in the beginning you could have brought back the phone, but paying a tax. Surely now you can do it for free but you still have to pay AT&T fees (since you can buy an iPhone in US only with an AT&T contract). But Steve has said that customers should not pay any fee to AT&T when refunding the iPhone. I believe the number of iPhone 4 returns will grow.
5. Free bumpers for everyone
So, Apple pretends to have found the root of all evil: a bad-algorithm-driven signal bar display. Still, Apple says that using a bumper the death-grip effect almost disappears. So, given that Apple loves their customers, every iPhone 4 owner will get a free bumper. And everyone who has bought an Apple Bumper will get a refund.
This is true only from now till September 30th. And only for Apple Bumpers. If I bought a third party’s cover to solve the death-grip problem, I shall not be refunded. If I’ll buy an iPhone 4 starting from October 1st, I will not get a free Apple Bumper. That is: after October 1st Apple is telling us that the death-grip issue will no more exist. How comes? Why? Please Steve, tell me. Tell us. You just said that no hardware fix is gonna come to the iPhone 4 design. How could you tell the whole world that you will care about your customers only till September 30th?
Conclusions
Apple makes very well designed products, is a leader in HMI (human machine interfaces) R&D, has reached every single point of the world with their iPods, and so on. The iPhone 4 has a obvious hardware-related issue. A phone that cannot make calls is not a reliable phone. Apple should face this problem and come out with a strong hardware fix. No free bumpers, and no “Just avoid holding it in that way” answers. We all love Apple, we all love Apple products and AppleCare, at least me. I hope Apple loves me the same way I love them. And I hope to be able to spend so much money on a fully functional product, as always. Know, we all know that Apple cares about their customers (at least so Steve Jobs said yesterday).
So why are they making fun of us?
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