Why do computers rot the brain?

[nradov]

Scuba once bubbled...
Computers calculate the tables for us real time during the dive. If not, than you'll have to expand my thinking.

Correct, but so what. We don't use tables. The idea of looking something up on a table in the middle of dive is ridiculous.

With respect to nitrogen bubbles, that was sarcasm open to misinterpretation. I still seem to think that with no nitrogen you get no nitrogen problems. With an increasing nitrogen load you get an increasing nitrogen problem.

Replace the nitrogen with helium and you eliminate the nitrogren problems, but then we are getting pretty far from the original question.

 

[nradov]

Scuba once bubbled...
On another note for tech divers. Computer can show your real time deco obligations with precision, based on your real dive profile applied to the tables - not a theoretical dive profile, or your present notion of your profile. Why the resistance? Not a rhetorical question.

Wrong again, and you still don't understand the difference between accuracy and precision, or why high precision is irrelevant to the problem at hand. Until you get past that I can't help you. Recommend you go back and read your Physics 101 textbook again.

 

[Scuba]

nradov

Correct, but so what. We don't use tables.

You don't use tables. What do you use? Magic dust?
Do you plan your dives with tables? I am really curious here, as I am always open minded to new ideas.

The idea of looking something up on a table in the middle of dive is ridiculous

Not if you have a computer do it for you. What's the matter, isn't your un-rotted brain fast enough?

Replace the nitrogen with helium and you eliminate the nitrogren problems, but then we are getting pretty far from the original question

Agree, this is an area I know nothing about. I'm sure other complications arise though. May I suggest you look into how a computer may be of help here.

Wrong again, and you still don't understand the difference between accuracy and precision, or why high precision is irrelevant to the problem at hand. Until you get past that I can't help you. Recommend you go back and read your Physics 101 textbook again.

Saying something is wrong is not a logically valid way to refute a premise. Sorry to disappoint you, but I never took Physics 101. But I do read the dictionary.
Accuracy: freedom from error
Precision: the degree of refinement with which an operation is performed or a measurement stated.

I seem to have explained fairly well that computers simply display the information the tables provide in a more useful, easier way for our challenged brains to use. Aqua Tec gave a good example of how this can be useful.

Unless you provide substance to prove your arguments you will be arguing with yourself. Plain dismissal only "proves" your point to yourself.

 

[Scuba]

Warning!

From the degree of intransigence displayed here by some table users to acknowledge some basic facts, I must conclude:

"Tables Rot Your Brain."

 

[nradov]

Scuba once bubbled...
You don't use tables. What do you use? Magic dust?
Do you plan your dives with tables? I am really curious here, as I am always open minded to new ideas.

Dives are planned using a set of heuristics learned in GUE classes and from reading posts by decompression experts on the Quest ( http://www.dirquest.com/quest.shtml ) and Techdiver ( http://www.aquanaut.com/bin/mlist/aquanaut/techdiver ) mailing lists. In some cases desktop decompression software is also used as a learning tool or an easy way to get a rough starting point; you wouldn't want to take a profile generated by any current software and actually dive it without significant modifications.

All of the information you need is out there and readily available, but don't expect me or anyone else to hand it to you on a silver platter. Get out and do the research for yourself. The decision about when to quit arguing and start learning is up to you.

 

[Jonathan]

I tried staying out but could not resist.....

Of course computers rot your brain - you've just got to go into any pub and watch what happens when the till breaks down and they have to do mental arithmatic - people just can't do it these days!

Back 30 years ago before I owned my first calculator my mental arithmatic was pretty good (for a six year old) it soon went down hill. But having said that I still amaze people with how quick my mental arithmatic is when it comes to sales tax. In the UK sales tax is 17.5% and fortunately for most our prices in the shops include sales tax in the displayed price. But what is so difficult about working out 17.5 % - nothing!

When I first started diving 3.5 years ago when the instructor asked for opinions about whether to use a computer I piped up - "No way - they might crash!". Silly me thinking that dive computers ran on microsoft... ( A little aside if they did and you got the blue screen of death on deco dive it would add a whole new meaning unless you have backups). He persuaded me otherwise - OK yeah he wanted to sell me one, which he did, but it is nice to see he uses the same one. Also as he was a physics teacher and had many more dives including being a try mix diver (not sure if he's an instructor on that one but certainly up to that level he is) - I trusted him.

Still does not mean I trust my computer 100% but I always plan a deco dive using tables and then dive the computer. If the computer goes phut (which unfortuantely my VR3 did once - but whilst doing the stops) I can finish the dive using tables. I will have enough gas because as has been pointed out you can get out of the water quicker using computers so another safty margin.

If you are doing technical diving you must be able to work out the tables as well - which I am sure Aquatec can. I have to admit when recreational diving I don't bother much - especially when you shelled out a fortune for a live aboard and are out of the water 30 minutes before anyone else and miss the night dive.

Jonathan

 

[Scuba]

nradov,

Thank you for your reply.

You are now in an area way above my present knowledge. I would only imagine that this heuristics approach may introduce a greater degree of speculation, than that offered by the possibly more tested tables. If the inaccuracy of the tables is large enough, I can understand trying to improve on it by using other methods. You know what your doing.

Wasn't trying to get a freebie, but since you've offered.....

 

[AltonK]

I hate to bring it up but the tables are computer generated. Unless, of course, you got some really old tables. So you are using a computer and a mathmatical model either way. I guess it's just up to you to decide who does the final tally, you or another computer.

 

[AltonK]

So DIR guys use Heuristics interpretations of mathmatical algorithms expressed as computer generated tables. The inputs to these Heuristics are gross approximations to their actual profiles (square)

As an adjective, heuristic (pronounced hyu-RIS-tik and from the Greek "heuriskein" meaning "to discover") pertains to the process of gaining knowledge or some desired result by intelligent guesswork rather than by following some preestablished formula. (Heuristic can be contrasted with algorithmic.) The term seems to have two usages:
1) Describing an approach to learning by trying without necessarily having an organized hypothesis or way of proving that the results proved or disproved the hypothesis. That is, "seat-of-the-pants" or "trial-by-error" learning.

2) Pertaining to the use of the general knowledge gained by experience, sometimes expressed as "using a rule-of-thumb." (However, heuristic knowledge can be applied to complex as well as simple everyday problems. Human chess players use a heuristic approach.)

Whereas Dive computers use algorithms to compute the established mathmatical models and accurate depth profiles.

The term algorithm (pronounced AL-go-rith-um) is a procedure or formula for solving a problem. The word derives from the name of the mathematician, Mohammed ibn-Musa al-Khwarizmi, who was part of the royal court in Baghdad and who lived from about 780 to 850. Al-Khwarizmi's work is the likely source for the word algebra as well.


I think I'll stick to my computing device.

 

[Uncle Pug]

AltonK once bubbled...
I hate to bring it up but the tables are computer generated.

Alton, it is a very good question and I think I've answered it a hundred times in one thread or another (not really but it feels that way at times. )

I'm not really sure what other folk's issues are in this thread but let me attempt to answer this one again... since the "Computers rot your brain" apothegm is often attributed to me.

As I see it computers per se are not the issue... yes we use computers to run decompression modeling software to generate decompression tables for staged decompression diving. (There is more to it than that but it is beyond the scope of this discussion.)

For recreational diving we (GUE/DIR) use something other than Software cut tables or dive computers... (but that too is beyond the discussion at hand.)

The issue, as I see it with *dive* computers is that most folks who use them don't develop the cognitive skills that would allow them to *mentally* model the dive as it unfolds. And why would they?

Again... the issue isn't computers per se... it is dive computers instead of profile awareness.

Some folks are not even aware that this profile awareness could be a beneficial thing. Just like some folks have never considered that the reason the viz is so crappy everywhere they dive is because... well... I had better not stray off topic...

Since we are profile aware we can manage our dive without recourse to tables or computers... in real time... making adjustments on the fly.