Σάββατο 26 Δεκεμβρίου 2009


Αλλαγή καλωδίωσης και επαναλειτουργία μετεωρολογικού σταθμού...

Mathematical Fiction


Do you like fiction and mathematics? Are you interested in what our society thinks about mathematicians? Then this is the right place...

http://kasmana.people.cofc.edu/MATHFICT/

O θείος Κούρτ...


Όταν ο Κουρτ Γκέντελ, ο πατέρας του φημισμένου Θεωρήματος της Μη-πληρότητας, ρωτήθηκε τι δίδαγμα προσφέρει το έργο του για τα ανθρώπινα πράγματα, είπε: «Μια κοινωνία που προσπαθεί να λειτουργήσει αποκλειστικά και μόνον με βάση τους κανόνες δεν θα μπορέσει ποτέ να λύσει τα προβλήματα που της θέτει η ζωή». Η θεωρία της Μη-Πληρότητας μάλλον έχει πολλά να μας διδάξει για τα μαθηματικά της καθημερινής ζωής και των κοινωνικών σχέσεων.
Ο Κουρτ Γκέντελ (1906-1978) είναι κατά πολλούς ο σπουδαιότερος μαθηματικός του 20ού αιώνα και χωρίς αμφιβολία ο μεγαλύτερος επιστήμονας της Λογικής στη νεότερη εποχή, ο άνθρωπος που o φον Νόιμαν, αποκάλεσε «νέο Αριστοτέλη». Η κορυφαία ανακάλυψή του, το Θεώρημα της Μη-πληρότητας, αποδεικνύει ουσιαστικά ότι ακόμη και στα μαθηματικά, το απώτατο προπύργιο του ορθολογισμού, η αποδεικτική δύναμη της Λογικής έχει όρια. Ότι δηλαδή σε κάθε θεωρία, όσο καλοδομημένη κι αν είναι, με όσα μη-αντιφατικά αξιώματα κι αν εξοπλισθεί, θα μείνουν πάντα αλήθειες μη-αποδείξιμες, απροσπέλαστες απ’ τη μέθοδο του «ένα και ένα κάνουν δύο». Αυτό φυσικά διόλου δεν σημαίνει ότι το Θεώρημα δείχνει πως η Λογική είναι σαθρό εργαλείο. Καθόλου. Βάζει όμως φραγμό στην παντοδυναμία της.

Παρασκευή 25 Δεκεμβρίου 2009

ΑΧΜΕΣ ο γιός του φεγγαριού...


Ένα θαυμάσιο ταξίδι στην καθημερινή ζωή και τον πολιτισμό της αρχαίας αιγύπτου...

How to Setup Keyboard (Language) Indicator & Install Foreign (Language) Fonts in Ubuntu

1. On an Empty area of the Menu, right-click & select "Add to Panel...".

2. On the "Add to Panel" window that shows up, scroll down with the scroll bar on
the right & under the Utilities section, select "Keyboard Indicator".

3. Click on the button named "Add" & a Keyboard Indicator Icon should appear in
the middle of your Menu Toolbar (e.g. in My Computer, a "USA" keyboard
indicator showed up - in your PC, a diff Language could show, depending on
what Keyboard you selected when you installed Ubuntu)

4. Right-click on your "Keyboard Indicator" & select "Open Keyboard Preferences".

5. On the "Keyboard Preferences" window that shows up, select the Tab named
"Layouts".

6. Under the "Keyboard model", you should see the "Generic 104-key PC".

7. Under the "Selected layouts" section, YOUR installed Keyboard Layout should
show (e.g. as I said before in my case it is "U.S. English"). Click on the button
named "Add", to install a Second Keyboard Layout.

8. In my case, I selected "Greece".
Note:
If you select to install a Greek Keyboard Layout, do NOT expand the "Greece"
folder (you would get: Eliminate dead keys, Extended & Polytonic). Just select
"Greece" & click on the button named "OK". For other Keyboard Languages, you
are on your own to experiment & find out which selection works for you.

9. Now you should be able to see your installed "Selected layouts".
Note:
To install more Keyboard Layouts, follow steps 7-9.
To remove a Keyboard Layout, first select it & click on the button named
"Remove".

10. On the "Keyboard Preferences" window, select the Tab named: "Layout
Options"

11. Look for the option named: "Group Shift/Lock behavior" & expand it, to see its
options.

12. The following two options should be selected:

a. "Both Alt keys together change group." (this should already be
checked - leave it checked)
b. "Alt + Shift changes group." (check this too)
Note:
The combination "Alt+Shift", should change your Keyboard (Input)
Indicator, the same way it works in the Windows environment.

13. Click on the button named "Close" & test your "Alt+Shift" or "Alt+Alt"
combination to see whether the Keyboard (Input) Indicator changes on your
Menu Toolbar.

14. To Test whether your Ubuntu's Editor (mine is "gedit"), works with ALL your
installed Keyboard Layouts, select "Alt+F2". "Alt+F2" is the shortcut (way) to
launch the similar to Windows "Start\Run" window.

15. Inside the input box, type your favorite Editor's name (mine is "gedit").

16. Inside the Editor, try to type something in your English Keyboard & then try to
switch to your Greek Keyboard (or the one YOU installed), by pressing
"Alt+Shift". Again, try to type something in your (newly installed) Greek
Keyboard (or the one YOU installed) & voila!!! your Country's Keyboard is
setup & works Great!!!


Important Notes:

1. The (New) Keyboards you have ADDED, are installed ONLY for the User you are
currently Logged In as. If your Computer is used by MORE than one User, each
User MUST separately ADD / INSTALL their own preferred Keyboards. And that
includes the "root" user too!!!

2. The The (New) Keyboards you have ADDED, can ONLY be used to type Keyboard
(Language) Characters in applications / programs embedded to your Operating
System. The fact that you have installed them, does NOT mean that you can
USE them in separate applications / programs ALSO (such as the Open Office's
Writer - e.g. the equivalent to Microsoft Word).

3. In order to be able to type in your Open Office Writer with YOUR Language's
Fonts, you MUST install the appropriate Fonts for your Language.
For Example:
To be able to type in Open Office Writer (e.g. the equivalent to Microsoft Word) in
Greek you MUST go into a Windows PC and copy the ".ttf" (True Type Fonts) that
are used more often in typing Greek. In our case, copy: the "Times New
Roman.ttf", the "Arial.ttf" & the "Sans Seriff.ttf".
Alternatively, you could also search for these Fonts in the Internet.
Note:
You can NOT install ".fon" type Fonts in Ubuntu. ONLY ".ttf" (True Type Fonts).