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Filip Hráček
Works at Google
Attended Masaryk University, Brno
Lives in Prague
7,851 followers|11,986,277 views
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Writing, Dart, HTML5, UX, Looking busy
Employment
  • Google
    Developer Relations Program Manager, 2008 - present
  • Self-employed
    SEO & SEM Lecturer, 2007 - 2008
  • FAnn Retail
    2006 - 2007
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Map of the places this user has livedMap of the places this user has livedMap of the places this user has lived
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Prague
Previously
Brno - Osaka
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Introduction
Pracuji v Googlu. Snažím se přivádět Google technologie do ČR a pomáhat českým vývojářům je využívat. Mám rád palačinky.
Education
  • Masaryk University, Brno
    2001 - 2009
  • Kansai Gaidai, Osaka
    2005 - 2006
  • Vysoké učení technické, Brno
    2000 - 2001
Basic Information
Gender
Male
Other names
Filip Hracek, Philip Age, Filip H.

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Filip Hráček

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Android-powered bathroom mirror. 
When I couldn’t buy a smart mirror and made one instead
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Okay mirror. Remind me to visit Alice.
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Huge thanks to +Kenneth Endfinger and +Matthew Butler for their work getting WebSocket compression in #dartlang 1.14.

Kudos!

#CommunityFTW


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How to run your Parse app on Google Cloud: 
https://cloud.google.com/nodejs/resources/frameworks/parse-server

This is using ManagedVMs which scale automatically.
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Remember when webpack was the hip JS module bundled (for about half a year)? Well, the cool kids now use rollup.js.

http://rollupjs.org/
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Filip Hráček

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The onion decomposition of a network

The onion decomposition of a network is a recently introduced network fingerprinting technique. It can be used to identify structural properties of a network, such as ”tree-like” structure, ”loopy” structure, or the property of having an ”interesting“ sub-network.

Examples of networks that can be analysed in this way include purely mathematical networks; physical networks like transportation networks and power grids; and social networks such as collaboration graphs. The picture shows three mathematical networks: (a) the Cayley tree, in which all but the terminal nodes are connected to exactly three other nodes; (b) the Erdős–Rényi random graph; and (c) the square lattice, in which each node not on the boundary of the network is connected to exactly four others.

Under the picture of each network is its onion spectrum. This can be thought of as a summary of the onion decomposition of the network, which we describe below. The number and nature of the pieces of the onion spectrum can be used to gain insight into the structure of the original network.

The onion decomposition was defined a few months ago in the paper Network structure at multiple scales via a new network statistic: the onion decomposition by Laurent Hébert-Dufresne, Joshua A. Grochow, and Antoine Allard (http://arxiv.org/abs/1510.08542), and the picture shown here comes from that paper. The decomposition is a refinement of the previously known k-core decomposition, and it is called the onion decomposition because it is reminiscent of peeling an onion.

To explain how this works, we use concepts from graph theory. A graph is a mathematical object that can be used to model a network. A graph consists of a set of nodes, called vertices, and a set of edges, which connect pairs of vertices. We do not allow our graphs to contain more than one edge connecting the same pair of vertices, or to have any edges that connect a vertex to itself. The degree of a vertex is the number of edges emanating from it.

To decompose a graph, one first removes all vertices of degree zero (isolated points); these vertices form the 0-shell of the graph. To form the 1-shell, one removes all vertices of degree 1, followed by all the vertices that become vertices of degree 1 as a result of this process, then iterating the procedure again and again until there are no more vertices of degree 0 or 1. The vertices that are removed at each iteration of the construction of the 1-shell are called the layers of the 1-shell. The construction of the 2-shell (and higher shells) follows a similar procedure: at each iteration, one removes all vertices of degree 2 or lower, until this is no longer possible.

The onion spectrum shown in the picture shows the relative abundance of vertices in each layer within each shell of the corresponding graph. Each connected piece of the picture is shown in a different colour and corresponds to a shell, and each dot corresponds to each successive layer of that shell. The vertical scale is logarithmic, which means that a straight line corresponds to exponential behaviour. The meaning of the colours in the pictures of the actual networks is different: the size of a vertex corresponds to its degree, and the colour of a vertex shows whether it is shallow or deep in the network. The original k-core decomposition gives less information, because it only keeps track of the k-shells, and not the layers within each shell.

The paper shows how to use the onion spectrum to read off properties of the original network. Exponential decay in the spectrum, like in the Cayley tree case, is indicative of the graph having a tree-like structure, whereas sub-exponential decay, like in the random graph case, suggests that the graph has a lot of circuits. It is a nice exercise to show that the Cayley tree consists of one big 1-shell, and the square lattice consists of one big 2-shell; it follows from this that the onion spectrum of each graph has only one connected component. 

Networks like these last two, whose onion spectrum has fewer components than a random graph, tend to be disassortative, which means that nodes tend to be connected to nodes that are somehow ”unlike” themselves. One way to illustrate this is to colour the vertices of the square lattice in alternating colours, like a chess board; something analogous can be done for the Cayley tree. 

Conversely, a network with more components than a random graph will tend to be assortative, meaning that nodes tend to be connected to nodes that are somehow like themselves. A good example of this that is studied in the paper is the collaboration graph of condensed matter physics papers on the arXiv preprint server. Some other real world graphs that are studied are the graph of a power grid, which is tree-like and assortative, and the network of roads in Pennsylvania. The road network graph has one particular shell that exhibits a change in its decay rate, which is indicative of the network having an interesting sub-network. In fact, the road system consists of several essentially isolated components.

Relevant links

Here's another post by me about assortative and disassortative networks: https://plus.google.com/101584889282878921052/posts/cHo5dMTQdsW
That post links to two other relevant posts by me, whose links I provide below for convenience.

A post by me about the mathematics of social networks: https://plus.google.com/101584889282878921052/posts/YV7j9LRqKsX

A post by me about the random graph: https://plus.google.com/101584889282878921052/posts/34guwy4ftWX

Wikipedia has more information about k-cores on its page about degeneracy in graph theory: https://en.wikipedia.org/wiki/Degeneracy_(graph_theory)

I'm glad that Google has fixed the discouraging bug that was corrupting the plus-one counts of posts. On the negative side, it looks like the selectedpapers.net site (which was associated with the spnetwork hashtag) is no more. Can anyone confirm or deny this?

#mathematics #sciencesunday  
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+Winchell Chung good question 
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Filip Hráček

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Our friends at #TrustWave are having great success with #dartlang
In 2015, Trustwave was one of the top digital tech employers in Chicago, clocking in a headcount of 350 at the time. It’s an impressive milestone, and one you can’t reach without a cream-o
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FYI: Robot lettuce farmers are coming.
 
Farming doesn't have to be a stone-age technology.
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Why lettuce? It's neither tasty, nor nutritious, simply used as optical and volume boost in dishes and on the plate.
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This is an amazing game.
 
My game, 10 Minute Barbarian is now available on Steam!  Hooray!

GameWatcher.com called it "wonderfully simple to pick up while being mightily difficult to put down".  _Rock Paper Shotgun_ said "“It is madness. It’s wonderful.” 

Come on down and play it today!
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Oooh, a deepdive into the collection package by +Natalie Weizenbaum.

I did not know about CanonicalizedMap, for example, and it's something I have needed before. Hope to see more deep dives like this.
I often find myself working with a class of Dart packages I like to think of as core library expansion packs. They aren’t the splashiest, they don’t produce cool demos, but they’re extremely useful. These expansion packages, ...
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Filip Hráček

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Pro vygenerování žádosti o elektronický podpis PostSignum, který uznávají české úřady, se používá nástroj, který vyžaduje Java SE 6.

Pro představu, Java SE 6 vyšlo koncem roku 2006 a přestalo být podporováno v roce 2013, dnes se už ani nedá stáhnout ze stránek Oraclu. Následující verze (7) vyšla v červenci 2011. Už zhruba 2 roky tu máme osmičku.

Nevím jak jinde, ale v Googlu je z bezpečnostních důvodů zakázáno na firemní počítače Java 6 instalovat už dlouhou dobu (snad jedinou výjimku tvoří security research VMka). Takže to nebudu instalovat ani na svůj osobní počítač.

https://www.cvedetails.com/vulnerability-list.php?vendor_id=5&product_id=1083&version_id=104592&page=1&hasexp=0&opdos=0&opec=0&opov=0&opcsrf=0&opgpriv=0&opsqli=0&opxss=0&opdirt=0&opmemc=0&ophttprs=0&opbyp=0&opfileinc=0&opginf=0&cvssscoremin=0&cvssscoremax=0&year=0&month=0&cweid=0&order=3&trc=53

Jinými slovy, jestli to chápu správně, abyste mohli komunikovat s českými úřady elektronicky (přes PostSignum), musíte používat nebezpečnou platformu.

Moje otázka: existuje alternativa k PostSignum, která by byla bezpečnější? Máte s tím někdo zkušenosti?

#DigitalGovermentWtf
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Tak srm zase rad ze datova schranka uz nepotrebuje instalovat nic od 602 a bezi v chrome
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Filip's Collections
Filip Hráček's +1's are the things they like, agree with, or want to recommend.
The Beatles – Hudba ve službě Google Play
market.android.com

The Beatles byla anglická rock'n'rollová kapela z Liverpoolu. Jejími členy byli John Lennon, Paul McCartney, George Harrison a Ringo Starr.

Artico Icons – Aplikace pro Android ve službě Google Play
market.android.com

• ARTICO strives to bring a piece of ART to your smartphones by combining only 3 basic and 2 supplementary colors. The icon pack is complete

Confusing sun cream labels being used to 'kill off morons'
newsthump.com

The needlessly confusing labels on bottles of sun lotion are a covert way of reducing the population and improving the gene pool, it has bee

Třídění programátorů quicksortem? - Zdroják
www.zdrojak.cz

Se kterým z algoritmů jste se na pohovoru setkali? Je to Quicksort, StackOverflowsort nebo Githubsort?

Dart Language Evolution Discussed in Ecma TC52
news.dartlang.org

The Dart standards committee (ECMA TC52) met on January 14th, 2015. The committee discussed several areas where the language could be improv

Charlie Hebdo
market.android.com

Parce que le crayon sera toujours au dessus de la barbarie... Parce que la liberté est un droit universel...Retrouvez Charlie Hebdo dans son

KOTOR
market.android.com

• Please note that KOTOR for Android has not been slimmed down for mobile in any way. It is the full KOTOR experience! As such the file size

Gamergate and Bullying
www.tbray.org

I’ve been watch­ing the “Gamergate” brouha­ha with sick fas­ci­na­tion. We all know the Internet’s got ug­ly cor­ners and sud­den­ly the ug­

Botanicula
market.android.com

* "One of the prettiest things on iPad" - Kotaku * "You absolutely need to check it out" (90%) - Toucharcade * "A bold, bright, and brillian

The Wolverine
market.android.com

Hugh Jackman returns as The Wolverine and faces his ultimate nemesis in an action packed life-or-death battle that takes him to modern day J

Česká škola: Jak se stát rodičem, jakým jste vždy chtěli být
www.ceskaskola.cz

Výchovné metody, návody a tipy bestsellerových autorek nyní v kostce! Celosvětově známé odbornice na komunikaci mezi dospělými a dětmi shrnu

Announcement: Readers who feel threatened by equality no longer welcome
games.on.net

When it comes time to make a point about an important issue the tool I usually default to is humour, or satire, because I find it’s easiest

Apollo 13 (film)
market.android.com

Apollo 13 je americký dramatický film, který v roce 1995 natočil režisér Ron Howard.

Indiana Jones a poslední křížová výprava
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Indiana Jones a poslední křížová výprava je třetí díl řady filmů o archeologovi Indiana Jonesovi, předchozími díly jsou Dobyvatelé ztracené

Serenity
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A passenger with a deadly secret. Six rebels on the run. An assassin in pursuit. When the renegade crew of Serenity agrees to hide a fugitiv

Ο Σημαδεμένος
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Ο Σημαδεμένος είναι μια Αμερικανική ταινία του 1983 με σκηνοθέτη τον Μπράιαν Ντε Πάλμα, σεναριογράφο τον Όλιβερ Στόουν και παραγωγό τον Μάρτ

The Dark Knight
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Visionary filmmaker Christopher Nolan's sequel to the highly successful "Batman Begins" sees Batman (Christian Bale) as he raises the stakes

Начало
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Ваш разум -- это место преступления. Кассовая суперзвезда Леонардо Ди Каприо играет в этом современном научно- фантастическом боевике "в рам

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Nice place, pleasant people. Not so great coffee.
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Best food I've had in Mountain View (outside Googleplex).
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