Do not set yourself on fire ...

Busca visual de imagens de imagens para todos: video online

2009-04-18T10:49:00.002-03:00

Finalmente achei o video online da apresentação que realizei em Set/2008 na PyconBrasil 2008 sobre o isk-daemon e projetos relacionados.

Video:

Slides:

isk-daemon: busca visual de imagens para todos

View more presentations from Ricardo Cabral.

Image search code from imgSeek ported to the Xapian search library

2009-03-15T12:52:00.002-03:00

Similar to what digiKam did, the Xapian opensource search engine library has also ported imgSeek code into its code base in order to provide content-based visual search features.

Quick note for Nokia owners trying to upgrade the firmware under VMWare/Parallels

2009-03-02T17:41:00.003-03:00

Avoid doing it under virtual machines. Nokia's firmware update system restarts the cell phone dozens of times as part of the upgrade process so the host and virtual machine will get all confused and as soon as the host machine refuses to "forward" a USB connection to the hosted OS, the upgrade process will stop due to a disconnection. This may cause severe damage to your cell phone (taking it back to a Nokia care center could be the only way out, so they can "re-flash" your phone ROM).

When trying to upgrade my E71 to the latest v200.21.118 firmware using Parallels under OSx I got one such aborted process, but luckily it worked flawlessly when trying again with a real Windows XP.

Other quick tips:

Backup all cellphone data and check if your backup works before the whole process. Using "Tools -> Memory -> Options -> Backup phone memory" from within the phone worked fine;
Remove the microSD card before the process, just to be sure;
Avoid doing it under Windows Vista, as some have reported similar problems.

Some references with more details:

Nokia Support Discussions - E71 disconnecting during firmware update - Eseries Devices and Communicators - Nokia Support Discussions

Nokia Support Discussions - E71 firmware update - for dummies - Software Updates - Nokia Support Discussions

Nokia Support Discussions - Recovering from a failed firmware update. - Pool of Knowledge - Nokia Support Discussions

Nokia Support Discussions - Update failed on my N73 - Software Updates - Nokia Support Discussions

HELP! Nokia Software Updater Seems Stuck!

How to Update your Nokia with Nokia Software Updater (NSU) - Bandung-Flasher.com GSM CDMA Cell Phone Repair Forum

Nokia Support Discussions - Recovering from a failed firmware update. - Pool of Knowledge - Nokia Support Discussions

Bricked E71

Bricked Nokia E71 » JRRZZ Blog

Nokia E71 adoption

2009-02-26T18:23:00.003-03:00

Interesting statistics from Flickr: Nokia E71 adoption seems to be increasing faster than any other previous model.

(extracted from Flickr statistics)

Simple incremental backups using Amazon S3 and Brackup

2009-02-17T23:06:00.005-03:00

I've been using the opensource Brackup tool to backup some of my documents and photos to the cloud (Amazon S3 - which charges as little as $0.150 per GB per month).

This should work on many platforms:

Install Brackup (implemented in Perl) using CPAN:

$ sudo perl -MCPAN -e shell

once inside the CPAN shell:

cpan> install Net::Amazon::S3
cpan> install Brackup

Now configure Brackup (".brackup.conf" on your home directory) by defining some file sources and an S3 account target:

[TARGET:s3_pers]
type = Amazon
aws_access_key_id = 1xxxxxNxxxxxFxx9xWx2
aws_secret_access_key = xxxxxxxYxRAoxuxDxrxxxxxxfxx4xxxxxxxxxdxx
keep_backups = 10

[SOURCE:documents]
path = /Users/ricardocabral/Documents
ignore = ^/books/
ignore = ^/Parallels/
ignore = ^eclipse
ignore = ^hdd
ignore = ^.svn

[SOURCE:pictures]
path = /Users/ricardocabral/Pictures
ignore = ^iPhoto
ignore = ^.svn

The commands I have on a cron job are:

brackup --from=documents --to=s3_pers -v
brackup --from=pictures --to=s3_pers -v

To restore a backup after a disaster, one can get all remote files describing "backup snapshots" with:

brackup-target s3_pers get_backups

Then choose the backup snapshot descriptor file corresponding to the point in time you want to restore and do:

brackup-restore --from=documents-1214139675.brackup --to=/target/dir --all

dvipdf dvips: Problems with file writing; probably disk full

2008-12-21T23:51:00.002-02:00

Another attempt to save others time.

I was getting this error when trying to generate PDF from LaTeX source using dvipdf.

dvipdf> Note that an absolute path or a relative path with .. are denied in -R2 mode.
dvips: Could not find figure file pdf:dest; continuing.
Note that an absolute path or a relative path with .. are denied in -R2 mode.
Error: /syntaxerror in (binary token, type=137)
Operand stack:

Execution stack:
%interp_exit .runexec2 --nostringval-- --nostringval-- --nostringval-- 2 %stopped_push --nostringval-- --nostringval-- --nostringval-- false 1 %stopped_push 1905 1 3 %oparray_pop 1904 1 3 %oparray_pop 1888 1 3 %oparray_pop 1771 1 3 %oparray_pop --nostringval-- %errorexec_pop .runexec2 --nostringval-- --nostringval-- --nostringval-- 2 %stopped_push --nostringval--
Dictionary stack:
--dict:1146/1684(ro)(G)-- --dict:0/20(G)-- --dict:71/200(L)-- --dict:206/300(L)-- --dict:43/200(L)--
Current allocation mode is local
Last OS error: 2
GPL Ghostscript 8.62: Unrecoverable error, exit code 1

and finally this apparently meaningless error:

dvipdf> dvips: Problems with file writing; probably disk full.

The solution in my case? Using dvipdfm instead of dvipdf. As far as I know dvipdfm is just a better implementation of dvipdf.

Some reasons for similar problems when rendering LaTeX into PDF:

too many embedded images
runaway commands (unclosed/unbalanced command braces)
buggy libraries/dependencies

Finally got my MSc degree in Computer Science!

2008-11-29T00:56:00.004-02:00

I've done the final presentation this morning and everything went well.

What to do with the degree? Not sure. Actually, this question doesn't make much sense.

Am I relieved? You bet so.

Did I get tired of giving the same reply (i.e. I guess soon) when asked when I would be done with it? Oh yeah.

Here's the abstract for the MSc dissertation:

This dissertation offers two major contributions: (1) to evaluate the suitability of recommender algorithms for social networks. Such recommender algorithms may receive as input not only the social graph of these networks but also content-based data from recommended items.

For such, the relevant characteristics of social networks and the most important recommender techniques for these tasks will be surveyed. Special attention is given to the web-based system for social photo-sharing called Flickr and to the employment of visual metrics for image similarity.

The second contribution (2) is the construction of a framework for the modeling and analysis of social networks, as well as aiding the empirical study of recommender algorithms on these contexts. Also part of this framework are the best practices adopted throughout the work done on this dissertation, such as: techniques for the gathering, analysis and visualization of data; social networks classification; identification and modeling of recommending tasks within these contexts; implementation of algorithms and their architecture.

The relevance of such contributions lies on the enormous amount of information available online and on the ever-growing complexity of the relationships between this data. In this context, recommender systems may provide a great aid for end-users.

On related news, I've submitted a paper to the Social Networks track at WWW2009 with the following abstract:

In this paper, we present a framework for specifying recommenders within the context of Social Media sites such as Flickr or Last.fm. Based on the standard SIOC ontology, we show how the various recommendation problems can be defined. We also present a general software framework for implementing recommenders based on this model framework, and show some results obtained by one recommender built using it.

Why publishers treat book footnotes as endnotes?

2008-11-20T17:24:00.002-02:00

From my experience this seems to happen with virtually all books: most of the time the important remarks made by the author about a passage are referenced and placed at the end of the book. The whole process of getting to the actual text of the footnote is really annoying: memorize the page and section you're at, find the page at the end of the book where the notes are, realize that you've just forgotten what reference number you were looking for, switch back to the page you were currently reading etc etc. The effect of this cumbersomeness on me is that I seldom read any footnotes. Why not simply placing the footnotes at the end of the current page? It makes a lot more sense to me. Well, I'm definitely missing something about why it's not the other way.

Visual image search code from imgSeek ported to digiKam

2008-11-19T11:03:00.005-02:00

Glad to know that the fast multiresolution image querying techniques implemented at my imgSeek project have been ported into digiKam:

During my digiKam presentation at LGM2008 i have introduced the concept to be able to search duplicates items around the whole collection of photos. But the concept is not just limited to find the similars photos by using copy, it even allows user to drawn a sketch of photo what user memories and shows photos what has similar shapes and colors as on sketch.

This is not a new concept in fact. An old program for Linux named imgSeek provide already this feature. By my opinion, it's time to update old interface of ImgSeek and make it more suitable for end users by implementing the technology into digiKam.

The old PyQT-based user interface for imgSeek certainly needs a rewrite, and integrating the image processing code into a more stable photo management tool like digiKam makes perfect sense. I haven't tried it yet but congratulations Gilles Caulier and Marcel!

Quick thought of the day: Depressing and challenging facts of life

2008-11-18T22:02:00.001-02:00

First the depressing one: All the people around you either looking or acting strange (in a bad way) are actually trying to do their best. Now imagine who they really are when no one is around looking.

Challenging one: most of the important things in life are non-linear and hence the beauty of life lies on its unpredictability. The amount of effort you put into something is not proportional to your success. Split-second decisions may have an impact on your entire life (think about that quick moment when you decided to accept a job offer or decided to get married).

iTunes script for opening the Last.fm web page for the track or album of the song currently playing

2008-10-05T17:43:00.001-03:00

I've created two simple iTunes AppleScripts for opening the Last.FM web page for the track or album of the song currently playing.

To install, just drag the files to your /[username]/Library/iTunes/Scripts/ folder. If there is no folder named "Scripts" there, create one and copy the files into it. AppleScripts placed in this folder will be listed in the iTunes Script menu.

Language most spoken on Twitter

2008-09-10T00:58:00.005-03:00

I got curious so here's some stats I've been gathering.

Twitts are culled from the public timeline every minute and language (see code definitions) is detected by Google.

The most spoken language will always have a ceiling value of 100, so a language with a value of 20 is 5 times less common than the most spoken.

Graph is updated every 30 minutes with the stats for the current day.

Web apps user experience: not exactly improving

2008-09-05T00:42:00.003-03:00

Take a quick look at this. First impression: "oh yes, these admin interfaces look really sleek". Second thought: each of them presents different UI concepts for doing the same tasks, UI elements (menu bars, status bars, sliders, buttons) are inconsistent across (and sometimes inside) them etc etc.

Poor users...

I've removed daily del.icio.us posts from the blog RSS feed

2008-09-03T23:27:00.002-03:00

Why? Well, I guess they may be too annoying for people only interested on the other lengthier ramblings which I occasionally write here on this blog.

So from now on if you're interested on my del.icio.us usage habits, try subscribing to http://feeds.delicious.com/v2/rss/nieder1 or even better: subscribe to my FriendFeed at http://friendfeed.com/rncabral?format=atom which includes more online activity (twitter, amazon, last.fm etc etc)

Ubiquity commands

2008-08-28T12:01:00.004-03:00

Expect a lot of cool stuff coming out of the Mozilla Ubiquity project. Think of it as SIMILE meets Quicksilver right at Firefox's heart.

I've created so far a few commands:

add-to-twine that brings up the dialog for posting the current page to a Twine.
lastfm-search for keyword searches on Last.fm
scholar-search for keyword searches using Google Scholar

Zoomii books: interesting but makes me dizzy

2008-07-06T19:08:00.002-03:00

Zoomii books, the "real" online bookstore is quite interesting and extremely well implemented. But still, I sort of miss it's point. Amazon's own shopping experience is still unbeatable. To some extent, Zoomii just transposed to the web the same old bookstore browsing experience which makes most people dizzy: OMG! so many books! How do I compare them? How are they related? There are too many shelves and aisles on this floor and there are still two floors on this bookstore to visit!

Greasemonkey DZone link redirector

2008-07-06T13:43:00.003-03:00

Here's a simple Greasemonkey script I did to automatically redirect the browser to the article itself when browsing DZone, skipping the annoying summary/comments preview page.

Useful when opening articles from the DZone RSS feed.

Install

Basic and digest HTTP authentication when using Google App Engine URL fetch API

2008-05-31T00:26:00.004-03:00

When using Google AppEngine's URL fetch API it's not obvious how to do a basic digest HTTP/S authentication, so here's a self-explainable code snippet for doing so:

import base64

username = "johnsmith"
pw = "cookie1234"

encoded = base64.b64encode(username + ':' + pw)
authstr = "Basic "+encoded

url = "https://api.del.icio.us/rename?new=bla1&old=bla2"

mheaders = {'Authorization':authstr,}

result = urlfetch.fetch(url,headers = mheaders)

Other useful HTTP request headers you could add to the mheaders dict above are:

"User-Agent" : "Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-US; rv:1.8.1.14) Gecko/20080404 Firefox/2.0.0.14",
"Accept-Charset": "ISO-8859-1,utf-8;q=0.7,*;q=0.7",
"Keep-Alive": "300",
"Connection": "keep-alive",
"Accept": "text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5",
"Cache-Control": "max-age=0",

both of these were very handy when implementing the del.icio.us tag cleaner.

Reference list of interview questions for a software engineer position

2008-05-29T22:55:00.002-03:00

These are all non-technical and have been collected from several websites. They're also ordered by what I would try first.

So, tell me a little about yourself.
What are you passionate about?
What relevant experience do you have?
Do you have any questions to ask me?
Questions on the projects listed on the Resume.
Tell me what you know about this company.
Have you done anything to further your experience?
How do you keep yourself updated on the latest tools, techniques, technologies etc?
What steps would you go through when given a though problem to solve involving a completely new technology?
What motivates you to do a good job?
Talk about the last 2 technical books you read.
If given a new programming problem, what is your first step in producing code?
Tell me a suggestion you have made that was implemented.
What are the really important aspects of software development?
Is there anyone you just could not work with?
If your previous co-workers were here, what would they say about you?
Has anything ever irritated you about people you’ve worked with?
What is your ideal team size?
How would you deal with changes being made a week or so before the ship date?
Why do you want to work at X Company?
How would you deal with a bug that no one wants to fix?
So, explain why I should hire you.
If you had enough money to retire right now, would you?
What’s your greatest strength?
What’s your biggest weakness?
What have you learned from mistakes on the job?
What do you like about your current job? What don't you like?
How would you rate your current management?
How are you when you’re working under pressure?
Are you willing to put the interests of X Company ahead of your own?
Let’s talk about salary. What are you looking for?
Why are you looking (or why did you leave you last job)?

Some additional tips.

mdworker process 100% CPU usage on Apple OS X

2008-05-29T15:55:00.002-03:00

I've noticed more than once a very high cpu usage on OSX and it turns out that the culprit was the mdworker process from Spotlight (text indexing service).

There seems to be several causes to this. In my case the reason was that it was trying to index the contents of a zipped file currently being downloaded by Transmission (bittorrent client). The same could probably happen for any other zip file or directory full of files being downloaded by another tool.

The solution was to add my download directory to Spotlight's ignore list: System Preferences -> Spotlight -> Privacy tab -> Drag your typical download location to the list.

Restarting Finder and Spotlight after that is a good idea.

Trânsito do Rio de Janeiro e São Paulo no celular em tempo real

2008-05-12T01:21:00.004-03:00

Aponte o browser de seu celular para http://transito.isnotworking.com/ e acompanhe o trânsito em tempo real nos principais corredores do RJ e SP.

Atualizado a cada 3 minutos com informações do MapLink e CET-RIO.

Quick note to Mr. Gladwell

2008-05-09T23:24:00.002-03:00

Your articles and books are very interesting, but please avoid making them this long.

Amazon Kindle e-book reader return over investment

2008-05-06T22:57:00.004-03:00

I've fallen in love with the Amazon Kindle e-book reader the first time I heard of it, several months ago. I believe it hadn't even been available for ordering yet. But alas, I live in Brazil so I wouldn't enjoy one of its best features: downloading books wirelessly and instantly without paying for bandwidth or messing with wireless providers. All of that at any time of day or night and at any place in the country (no WiFi required).

Today I just came across a great Kindle review and noticed that the author did mention how cheap Kindle e-books can be compared to dead-tree versions of it, but he didn't do a back-of-the-envelope return over investment calculation for it:

A brand new Kindle costs you around $410. Hardcover book releases cost on average $27 (shipping included), which you can get on Kindle for $10. So for each new book release you buy on Kindle you save $17. But wait, you're not going to buy only new releases. Let's say you buy a few backcatalog items, which sell at Kindle for $6. So let's mix those two together and say you save on average $19 for every book you buy.

That means Kindle pays itself after 22 books. Which for many book lovers means 2 years or less of usage. If you consider all the added value of not carrying heavy books around and keeping many books on its internal memory available for you to reference or skim at your convenience, then that return comes even earlier!

Side-note 1: Actually, maybe this is exactly the math Mr Bezos wants us to do: he doesn't really want us to buy Kindles, but to buy these 22 e-books to make Kindle pay itself. Profit margins for paper books are probably ridiculously low (compared to e-books) so he wants to get away from it as soon as possible.

Side-note 2: If, like me, you're outside the USA, here are some reasons why it may take some time for it to become more widely available:

It uses Sprint to download books, which is only available in the US. This is one of the main features of the Kindle over all other ebook readers, and it is truly a wonderful feature.

Another answer is that many of the publishers whose works they are offering do not permit Kindle to sell them abroad, as they often have contracts with vendors in those other countries who do not want to see competition coming from the US.

A third answer is payment. It is true that you can use a credit card issued in another country for payment of a US bill, but it imposes some overhead on their operations, which being brand new most likely doesn't have full support for such things yet, including the problems of currency conversions.

Histórico dos fundos de investimento do Unibanco

2008-05-04T20:45:00.005-03:00

Compilei em uma única página web um histórico em forma de scatter plots dos principais fundos de investimento do Unibanco. Ajuda a saber o que os outros clientes andam fazendo em relação a esses fundos.

Segue o link:
Histórico dos fundos de investimento do Unibanco
(atualizado diariamente)

A maioria dos indicadores é obvio, mas apenas para detalhar: Captação = Captação geral de recursos - Resgates

Os dados são obtidos das paginas disponibilizadas publicamente pelo próprio Unibanco.

Sempre quis parar para aprender a investir direito (day-trading, mercado de opções, etc) mas nunca priorizei. Principal motivo é que não tenho paciência de acompanhar minuto a minuto e nem seria viável fazer isso no meu trabalho.

Alguns dos fundos historiados:

UNIBANCO INFRA-ESTRUTURA
UNIBANCO ENERGIA
UNIBANCO FLEX MULTIMERCADO
UNIBANCO STRATEGY
UNICLASS MULTI
UNIBANCO ADVANTAGE DI
UNIBANCO VALE DO RIO DOCE
UNIBANCO RENDA FIXA PLUS
UNIBANCO TELECOM
UNIBANCO CLASSE MUNDIAL
UNICLASS DI
UNIBANCO TIMING
UNIBANCO SUSTENTABILIDADE
UNIBANCO PETROBRAS
UNIBANCO BLUE
UNIBANCO RENDA FIXA
UNIBANCO LIQUIDEZ DI

Money saving tip for book lovers

2008-05-03T17:44:00.003-03:00

Try this quick estimate on the number of days needed for you to finish all your unread books: Multiply the number of books left by 300 (average number of pages in a book) and divide by the average number of pages you read daily (figure that out by dividing your weekly reading capacity by 7). Normally you'd need to divide by 365 again to get the years-till-next-buy estimate. You'll find out that you'll take a lot longer to hit the "Proceed to checkout" button again.