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stefanu

694 karma · joined January 17, 2011

Mentor, software engineer and data warehouse architect by day. Simulations, DSLs and complex systems by night. Author of Cubes Python OLAP (suspended).

Twitter: @Stiivi Github: https://github.com/stiivi/

[ my public key: https://keybase.io/stiivi; my proof: https://keybase.io/stiivi/sigs/5aNtNBrmNZFuMKkbG29vZXWVCkSteYgV7wYU6Wluc6A ]

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stefanu··on In praise of Objective C
... not only ObjectiveC is available for Linux and Windows as gcc's gobjc, but also GNUstep - kind of open-source Cocoa (former OpenStep): http://gnustep.org

See my comment above for GNUstep github repo.

stefanu··on In praise of Objective C
There is quite a lot implemented, they are trying to follow (as much as reousrces allow).

Btw. since February there is GNUstep repository on github: https://github.com/gnustep (base = Foundation, gui = AppKit)

stefanu··on How to make your github static page a blog
Looks like there are several similar projects sprouting recently:

Ruhoh – another static blog generator. from the creators of Jekyll Bootstrap: http://ruhoh.com/

It has also a quite nice blog API proposal: http://ruhoh.com/universal-blog-api/

stefanu··on Ask HN: Freelancer? Seeking freelancer? (March 2012)
SEEKING WORK - remote

Brewing data: focusing on data processing, analysis (OLAP), extraction/transformation/loading, data architecture, data audit and data quality measurement.

Mostly Python + SQL, might be Ruby, Objective C.

I am author of open-source OLAP Python framework Cubes.

* About me: http://stiivi.com

* Open-source projects: http://databrewery.org (Cubes Python OLAP and Brewery Data Stream Processing)

* Data brewery blog: http://blog.databrewery.org

* Github: http://github.com/Stiivi

stefanu··on Extension of MIT License for SaaS?
Basically I was thinking about adding this to MIT:

    If your version of the Software supports interaction with it remotely through a computer network, the above
    copyright notice and this permission notice shall be accessible to all users.
What I want to say is, that if the software is used in SaaS, then the copyright notice should be included in some about/legal/credits page/panel.

What do you think?

stefanu··on Internals of Cubes – Lightweight Python OLAP Framework
Thank you.

How long? I was working for around 5 years in (later with) a data warehouse in a mobile telco company, now I am doing "data brewing" as a freelancer. My favourite book is Star Schema The Complete Reference by Christopher Adamson. Very very brief introduction to OLAP and Cubes you can see in my slide deck: http://www.slideshare.net/Stiivi/cubes-7781602

Thanks, fixed the link.

stefanu··on Internals of Cubes – Lightweight Python OLAP Framework
Thank you.

There are couple of analytical services out there, as SaaS, that can connect to various third-party sites, databases or other data sources. However, what is missing is some nice, reusable, simple UI set of elements for pivoting and drilling down. The idea is that apps can use Cubes as module for providing aggregation and drill-down capability. Then you have a front-end module, either within the app or any external, that can connect to the Cubes OLAP API and you can do reporting as you like.

I'm not too much front-end guy, so any help would be appreciated. As mentioned in one of my other comments here, I've started https://github.com/Stiivi/cubes.js . Just proof-of-concept.

stefanu··on Internals of Cubes – Lightweight Python OLAP Framework
In addition to that, I've started to write a JavaScript library for the Slicer server (not mentioned in the blog post). I am just starting with JS, so pardon my style. The sources can be found here: https://github.com/Stiivi/cubes.js No examples yet, however the goal is to be able to browse aggregated data directly from JS and transform them into tables/charts.

Concerning backends: I have not much time to write other backends, however, if anyone is interested in helping me with them, just drop me a line. I would like to have at least nicer star-schema browser and perhaps the mongo DB backend.

stefanu··on Hello 2012: Meet Digital Nomads
Very interesting introductory post about digital nomads. Nice to have nomads around, however do we have nomad-friendly economy? Are businesses nomad friendly? What about the law?

Follow up: Hard times for nomads? Only for now... http://news.ycombinator.com/item?id=3509589

stefanu··on Why iCloud won't beat Dropbox and the failure of Airdrop
Drop box is just obvious next step: taking file-system to the cloud. Apple is just unfortunately clumsy or it is up to something...

I have Apple ecosystem in my home and within couple of my friends. I just love how it all works together well. Except one thing: sharing and syncing.

The document sharing between computer and ipad through iTunes->iPad->Apps->App (in second! list) is just overcomplicated and does not even allow real synchronisation. That way of sharing breaks logical document coupling as well (by-project, for example). The way of sharing documents between apps is limited as well and it forces me to have duplicates... There many other little things.

I think (and strongly hope) that this is just a transient period. Looks like Apple would like to get rid of classical file system "feel" on the user's side. They either have no human friendly solution yet (measured on Apple standards) or want to do it step-by-step, so users can accommodate to changes gradually.

iCloud is application/document type based storage, iPad is application based file storage. They even added a view to finder: "All My Files", which also hides classical file system way of browsing files.

I do not think that Apple is done with file management evolution. But I feel, that the classical hierarchical file system structure is not the way to go in the cloud based file system...Consider not only your document syncing, but also synchronized file sharing with custom categorization...

stefanu··on Dark Sky - Weather Prediction, Reinvented
In Slovakia we have been using similar feature for couple of years now. It is far away from being that pretty and interactive. It serves it's purpose for knowing how the weather will be evolving during the day: http://www.shmu.sk/sk/?page=1&id=meteo_num_mgram Charts from top to bottom: temperature (in Celsius), clouds (total, red-lower, green-middle, blue-upper), precipitation, atmospheric pressure, wind speed and last is wind direction.

Very useful for example when I want to go inline skating on the Danube dike in Bratislava: how much time do I have until it starts raining? :-)

stefanu··on Data Brewery (open-source data processing + OLAP in python)
Not yet, I would like Brewery to be distributed, I had it in mind while designing it. See my general post about brewery.

@Stiivi - author of Brewery/Cubes

stefanu··on Data Brewery (open-source data processing + OLAP in python)
See my post about the projects: they are very young, just little over half-year old - performance was not focus yet. I would definitely have them to be able to handle more data more efficiently, however, goal more on simplicity of use than on ability to process really huge amounts of data (like telco data - background where I come from).

Before I answer your questions (I assume that you are referring to Cubes - OLAP framework), I think it would be good to note, that Cubes has pluggable backends. Currently simple denormalisation-based SQL backend and MongoDB backend are implemented. I want to have them more advanced.

* Will data be fetched from the database for each query?

- currently yes, however we did some experiments with plain HTTP caching of Cubes/Slicer server and it worked pretty nicely for our current needs

* Is it possible to have dimensions with millions of values and expect reasonable query times?

- not tested yet

* Looks like it supports advanced topologies and hierarchies. How will dimensions with a high carnality affect performance?

- right, it supports hierarchies, however same as above: not tested yet for performance

I am open to any commeents/suggestions regarding the framework(s).

Stefan Urbanek, @Stiivi on Twitter (author of Cubes)

stefanu··on Data Brewery (open-source data processing + OLAP in python)
I'm the author of Brewery/Cubes. Both projects are very young - started last year, in December 2010.

As for Cubes: goal is to create light-weight framework with pluggable backends. Currently simple SQL backend and MongoDB backend are implemented.

Some public projects that are using Cubes for OLAP are:

Donations for sport and culture:

http://granty.transparency.sk/en/

Public procurements of Slovakia (still under development):

http://vestnik-test.democracyfarm.org/en/report/all?cut=date...

If you are asking about performance, my answer is: I do not know yet, haven't stressed it too much. I would very like to hear any feedback and/or recommendations. Current focus was on simplicity and easy of use, performance will come later.

For brewery, here are some blog notes:

http://blog.databrewery.org/

Presentation where data brewery was used in a project:

http://slidesha.re/i9O4kC

I hope to prepare more information soon, with examples. I want data brewery to be more distributed with cusomisable nodes (like you would be able to use a distant server as a processing node or part of processing stream).

Goal of data brewery is to provide "way of working with data streams", focusing more on data analysis than on data transformation. However, it does not mean that you would not be able to use it for the further.

Anyway, I would appreciate any feedback, and gladly answer any questions. I am also looking for cooperation, if you are interested, drop me a line.

Stefan - @Stiivi on twitter, author of Data Brewery/Cubes

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