Bac 2014

Le taux de réussite au bac 2014 est 87.9%. C'est beaucoup ? Oui mais il ne s'agit que de ceux qui passent le bac. Alors combien cela fait-il en rapportant ce taux à une génération d'élève ? La réponse ici

La proportion de bacheliers dans une génération est ...

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Copyright Yourself with Domain names - No more registrars needed

Some time ago I wrote a article explaining how to guarantee the anteriority of a document (the timestamp), as well as the author, using the bitcoin block chain, by sending a small amount to a particular address.

An alternative is to use the Domain Name System, and to register a ...

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Private, Confidential, Available and Cheap Cloud with VPS, NBD, LVM, SSHFS, ENCFS and Samba

I have been battling for a while to find the best way to outsource my data "in the cloud". I mean personal data: camera pics, documents, backups, etc. What I want to achieve is:

  • no worry about hard disk failure, theft, fire and so on (you never know - our life ...

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Copyright Yourself with BitCoin (et. al) - No more registrars needed

Looking at Bitcoin addresses and the way they are constructed, we can easily write a bash script that generates a valid address from any SHA-256 hash.

initialsha=600FFE422B4E00731A59557A5CCA46CC183944191006324A447BDB2D98D4B408  
ripemd160=`echo -n $initialsha | xxd -r -p | openssl rmd160 -binary | xxd -p`  
extripemd160=`echo 00$ripemd160`  
finalsha=`echo $extripemd160 | xxd -r -p ...
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Premier post

D'une longue série j'espère.  Je vais faire un voeu pieu, celui de poster régulièrement le fruit de mes pérégrinations imaginatives et autres compte rendus d'expériences diverses qui pourraient ou auraient pu servir à d'autres.

Comme dirait la SNCF, les prochains posts paraîtront avec une fréquence que ...

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A Top-Down Proof Procedure for Generalized Data Dependencies

Abstract

Data dependencies are well known in the context of relational database. They aim to specify constraints that the data must satisfy to model correctly the part of the world under consideration. The implication problem for dependencies is to decide whether a given dependency is logically implied by a given ...

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