Random me

Pet project: Metadata Flask

noreply@blogger.com (Ricardo Cabral) — Thu, 23 Jun 2011 22:20:00 +0000

Just a quick announce of a pet project I started a few months ago. Unfortunately I've already slowed down work to a halt as I focus on finishing my MBA dissertation.

The objective of the Metadata Flask project is to provide tools for supporting the process of finding, collaborating and working with metadata on an open and linked-data web.

Nowadays when players of an industry vertical, say: commodities producers and large scale retailers like Walmart, or Oil & Gas equipment producers and Oil companies/operators want to define and evolve data exchange formats they have to build their own infrastructure for documenting, referencing and hosting data exchange definitions.

These players frequently need to exchange a lot of data for describing what is produced, their specs, how they are sold, who wants to buy etc. So they come up with metadata definitions like WSDL contracts, XML schemas, CSV/JSON templates and so on.

I believe their work would be a lot easier if infrastructure for hosting, exchanging, discovering, collaborative editing, moderating and many other metadata related processes was already in place.

The goal is ambitious, the problem not well defined and "tractable" right now, so I started investigating what open data sets are available out there. What I realized is that many of them couldn't be found using general purpose search engines, so I started a first subproject, the Open Data Directory, which is a search engine for open data sets published by governments, private companies and other organizations. It already indexes 360K+ datasets from many sources, and traffic is slowly increasing as search engine bots index its contents.

I wish Amazon would innovate faster on it's Kindle OS

noreply@blogger.com (Ricardo Cabral) — Thu, 23 Jun 2011 14:13:00 +0000

Amazon seems to be really slow and conservative on features for the embedded software (OS) running on it's Kindle devices. The last update (v3.1) was on Feb 2011. I don't see why they can't let users opt-in for cutting-edge feature experiments. This way they could easily roll-out wireless beta updates to advanced users and experiment with feature designs/variations, collecting usage data on what works/doesn't.

Some areas they could've been experimenting publicly for ages:

Social features: why stop at public note sharing via twitter/facebook? Why not integrating to services like Evernote, Instapaper, Delicious? Why can't it sync my notes to Amazon's website? It would be nice to be able to review them online.
Notes/highlights usability: The reading experience should be at least as powerful as the Real Thing. Why can't I attach notes to whole chapters or even books? Why restrict it to contiguous blocks of text? After all, the whole reading experience is mostly not about what I read, but what I thought about it, what I learned from it, how it applies to me, and people use notes for remembering these things.
Podcasts: it has enough storage and CPU for playing mp3s and downloading data on the background. Why not scheduling the download and managing podcasts?
Improve the experience for reading blogs. Why not integrating to Google Reader?

Calendário Compacto Brasil

noreply@blogger.com (Ricardo Cabral) — Tue, 23 Nov 2010 11:55:00 +0000

Uso há anos calendários compactos sempre que preciso raciocinar sobre datas. Segue versão com feriados do Brasil (Rio de Janeiro):

DOWNLOAD VERSÃO BRASILEIRA 2012

You know your "other side of the coin" book has failed when...

noreply@blogger.com (Ricardo Cabral) — Sun, 27 Dec 2009 15:37:00 +0000

... its "What Do Customers Ultimately Buy After Viewing This Item" list at the Amazon page shows all best sellers from the author you attack listed first and your book itself at 4th:

Of course it's hard to compete with Malcom Gladwelland no matter how good your counter-arguments are you would hardly sell more than him, but it's funny anyway.

Comentários sobre o Kindle 2 (Internacional) no Brasil

noreply@blogger.com (Ricardo Cabral) — Fri, 25 Dec 2009 22:36:00 +0000

Como já existem zilhões de reviews sobre o Kindle em inglês, faço um agora em português.

Em geral superou minhas expectativas. Enviei via correio para um hotel nos EUA durante viagem de trabalho e trouxe de volta comigo no avião. A conectividade 3G funciona perfeitamente no Rio de Janeiro. O contraste da tela poderia ser melhor mas a legibilidade é mesmo assim ótima. Poucos livros ou assinaturas de revistas não estão disponíveis para usuários do Brasil. No momento (dez/09) a assinatura do The Economist por exemplo não está disponível para Am.Latina.

As funcionalidades que mais gostei são: envio instantâneo e gratuito de amostras (normalmente umas 20 páginas do livro), a forma como ele salva automaticamente o lugar onde você parou em cada livro/revista e o dicionário embutido.

O preço de livros que não estão entre os mais-vendidos poderia ser bem menor. Por outro lado, a assinatura de algumas revistas é bem barata.

Comprar a capa de couro padrão vale muito a pena, alias, é indispensável.

O serviço gratuito de conversão de documentos da Amazon (enviar um html/doc/pdf anexo para fulano@free.kindle.com com a palavra "Convert" no assunto do email) até que funciona mas o suporte a PDF (repaginação etc) poderia ser bem melhor.

A leitura da maioria dos arquivos PDFs é bem dolorosa (quase impraticável: zoom in, zoom in, zoom out, pro lado, pro lado, zoom in, pro lado, zoom out...) pois ele não reajusta o layout dos documentos para tornar a experiencia mais agradável. Acho provável que melhore em poucos meses com o lançamento de novas versões do software que roda nele. Também espero que a forma como ele organiza e te permite navegar pelos livros melhore com esses updates.

Tenho usado o Calibre (gratuito, roda em PC/Mac/Linux) para agendar o download automático de feeds RSS (blogs) que possuem maior quantidade de texto nos posts. Tudo que preciso fazer é deixar o Calibre rodando no computador e ocasionalmente plugar o Kindle na porta USB para que ele envie os posts baixados. Ele já envia com o conteúdo indexado/categorizado. Funciona muito bem com os feeds do Estadão, O Globo, New Yorker, Economist etc. Tem milhares de "receitas" de feeds prontas para serem baixadas ou agendadas para download periódico automático.

A bateria realmente dura semanas, mesmo com uso diário (mas costumo deixar o wireless desligado). As ocasionais plugadas na porta USB para sincronizar os blogs é suficiente para deixá-lo sempre carregado.

ATUALIZAÇÃO 27/DEZ/2009: liguei hoje cedo para ler um pouco e a tela deu defeito na metade superior (foto 1, foto 2) tornando o Kindle inútil. Tenho carregado ele para cima e para baixo numa mochila e não me recordo dele ter sofrido nenhum trauma significativo, então parece que essa tecnologia e-ink da tela ainda é muito frágil.

Fiquei bastante chateado, já que as páginas do produto na Amazon deixam implícito que ele é bem resistente. É possível que o meu caso seja algum defeito de fabricação.

Pedi ajuda para eles por email e o procedimento padrão (recarga, reboot, refresh tela) não adiantou. Liguei para lá e em questão de minutos um atendente americano (bem atencioso por sinal) cadastrou no sistema deles o envio de um replacement sem custos previsto para chegar dia 30/dez. Espero que quando o replacement chegar no Brasil eu não tenha que pagar nada na alfândega. Terei 30 dias para enviar a minha unidade com defeito para eles.

ATUALIZAÇÃO 3/JAN/2010: Realmente Amazon não brinca quando diz que quer ser referência mundial em serviço ao consumidor. Replacement chegou com todos os impostos pagos em casa praticamente 3 dias úteis após reclamação. Enviei unidade com defeito por correio, nosso correio atrasou (feriados de virada do ano) e eles estenderam a tolerância de 30 dias para que você envie a unidade com problema (normalmente se você nao devolver o produto com problema após esse período eles cobram no teu cartão o valor total do replacement). Apenas mencionei o custo de envio pago ao nosso correio e eles já extornaram no meu cartão o valor gasto.

ATUALIZAÇÃO 28/DEZ/2010: Comprei um Kindle 3a. geração (o de cor grafite). Vantagens confirmadas em relação à 2a. geração (cor branca): realmente muito mais rápido, contraste da tela melhor, dimensões e peso bem mais confortáveis. É todo de plástico, dando uma sensação de ser menos resistente, enquanto que o da 2a. geração tem uma placa de metal leve nas costas. De qualquer forma continuo achando que todas as versões de Kindle são frágeis e não resistiriam a uma queda pequena: nada fundamental mudou na tecnologia da tela então acredito que elacontinua sendo o ponto mais frágil.

Calendário Compacto 2010 Brasil

noreply@blogger.com (Ricardo Cabral) — Sun, 13 Dec 2009 19:21:00 +0000

Uso há anos calendários compactos sempre que preciso raciocinar sobre datas e como não achei uma versão para 2010 com os feriados brasileiros, decidi fazer e disponibilizar.

DOWNLOAD VERSÃO BRASILEIRA 2010

Veja versão Brasil 2011 e próximos anos.

Busca visual de imagens de imagens para todos: video online

noreply@blogger.com (Ricardo Cabral) — Sat, 18 Apr 2009 13:49:00 +0000

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

noreply@blogger.com (Ricardo Cabral) — Sun, 15 Mar 2009 15:52:00 +0000

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

noreply@blogger.com (Ricardo Cabral) — Mon, 02 Mar 2009 20:41:00 +0000

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

noreply@blogger.com (Ricardo Cabral) — Thu, 26 Feb 2009 21:23:00 +0000

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

noreply@blogger.com (Ricardo Cabral) — Wed, 18 Feb 2009 02:06:00 +0000

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

noreply@blogger.com (Ricardo Cabral) — Mon, 22 Dec 2008 01:51:00 +0000

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!

noreply@blogger.com (Ricardo Cabral) — Sat, 29 Nov 2008 02:56:00 +0000

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?

noreply@blogger.com (Ricardo Cabral) — Thu, 20 Nov 2008 19:24:00 +0000

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

noreply@blogger.com (Ricardo Cabral) — Wed, 19 Nov 2008 13:03:00 +0000

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

noreply@blogger.com (Ricardo Cabral) — Wed, 19 Nov 2008 00:02:00 +0000

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

noreply@blogger.com (Ricardo Cabral) — Sun, 05 Oct 2008 20:43:00 +0000

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

noreply@blogger.com (Ricardo Cabral) — Wed, 10 Sep 2008 03:58:00 +0000

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

noreply@blogger.com (Ricardo Cabral) — Fri, 05 Sep 2008 03:42:00 +0000

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

noreply@blogger.com (Ricardo Cabral) — Thu, 04 Sep 2008 02:27:00 +0000

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

noreply@blogger.com (Ricardo Cabral) — Thu, 28 Aug 2008 15:01:00 +0000

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

noreply@blogger.com (Ricardo Cabral) — Sun, 06 Jul 2008 22:08:00 +0000

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

noreply@blogger.com (Ricardo Cabral) — Sun, 06 Jul 2008 16:43:00 +0000

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

noreply@blogger.com (Ricardo Cabral) — Sat, 31 May 2008 03:26:00 +0000

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

noreply@blogger.com (Ricardo Cabral) — Fri, 30 May 2008 01:55:00 +0000

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.