Главная | Actual Topics | Обратная связь | В избранное | Сделать домашней | Антиспам ;)
 System & Utilities
 Unix News
 OS Emulator
Каталог статей
Все статьи

Биллу Гейтсу тоже предлагают избавиться ...
Вымогательство в борьбе со спамом

August, 2018
Какой из этих ОС Вы отдаете большее предпочтение?

Mac OS
Windows XP
Windows 2003
Что такое ОС? :)

Другие опросы

Всего голосов: 326
Комментарии: 0

Архив Новостей
 August 2018 (2)
 July 2018 (11)
 June 2018 (13)
 May 2018 (10)
 April 2018 (14)
 March 2018 (11)
 February 2018 (13)
 January 2018 (13)
 December 2017 (14)
 November 2017 (15)
 October 2017 (19)
 September 2017 (18)
 August 2017 (13)
 February 2017 (14)
 January 2017 (19)
 December 2016 (16)
 November 2016 (16)
 October 2016 (21)
 September 2016 (18)
 August 2016 (16)
 July 2016 (16)
 June 2016 (20)
 May 2016 (18)
 April 2016 (15)
 March 2016 (22)
 February 2016 (17)
 January 2016 (15)
 December 2015 (15)
 November 2015 (22)
 October 2015 (20)
 September 2015 (17)
 August 2015 (25)
 July 2015 (20)
 June 2015 (23)
 May 2015 (21)
 April 2015 (17)
 March 2015 (19)
 February 2015 (9)
 January 2015 (23)
 December 2014 (9)
 November 2014 (13)
 October 2014 (12)
 September 2014 (18)
 August 2014 (20)
 July 2014 (10)
 June 2014 (12)
 May 2014 (12)
 April 2014 (10)
 March 2014 (22)
 February 2014 (10)
 January 2014 (8)
 December 2013 (26)
 November 2013 (53)
 October 2013 (40)
 September 2013 (48)
 August 2013 (63)
 July 2013 (56)
 June 2013 (52)
 May 2013 (49)
 April 2013 (67)
 March 2013 (74)
 February 2013 (63)
 January 2013 (62)
 December 2012 (62)
 November 2012 (66)
 October 2012 (68)
 September 2012 (48)
 August 2012 (75)
 July 2012 (60)
 June 2012 (71)
 May 2012 (69)
 April 2012 (85)
 March 2012 (86)
 February 2012 (90)
 January 2012 (81)
 December 2011 (103)
 November 2011 (118)
 October 2011 (74)
 September 2011 (2)
 June 2011 (110)
 May 2011 (118)
 April 2011 (111)
 March 2011 (112)
 February 2011 (101)
 January 2011 (119)
 December 2010 (117)
 November 2010 (118)
 October 2010 (131)
 September 2010 (117)
 August 2010 (226)
 July 2010 (351)
 June 2010 (305)
 May 2010 (319)
 April 2010 (343)
 March 2010 (329)
 February 2010 (311)
 January 2010 (312)
 December 2009 (266)
 November 2009 (156)
 July 2009 (101)
 June 2009 (279)
 May 2009 (365)
 April 2009 (348)
 March 2009 (347)
 February 2009 (323)
 January 2009 (318)
 December 2008 (237)
 November 2008 (155)
 October 2008 (334)
 September 2008 (310)
 August 2008 (343)
 July 2008 (362)
 June 2008 (322)
 May 2008 (494)
 April 2008 (1276)
 March 2008 (1658)
 February 2008 (250)
 January 2008 (6)
 November 2007 (1)
 September 2007 (1)
 June 2007 (1)
 May 2007 (1)
 March 2007 (1)
 January 2007 (2)
 December 2006 (1)
 October 2006 (2)
 September 2006 (1)
 August 2006 (2)

Exploring Contributors Centrality Over Time

System & Utilities

At the end of my previous post we concluded with yet another question. Indeed, on the 2017 KDEPIM contributor network we found out that Christian Mollekopf while being a very consistent committer didn't appear as centrality as we would expect. Yet from the topology he seemed to act as a bridge between the core contributors and contributors with a very low centrality. This time we'll try to look into this and figure out what might be going on.

My first attempt at this was to try to look into the contributor network on a different time period and see how it goes. If we take two snapshots of the network for the two semesters of 2017, how would it look? Well, easy to do with my current scripts so let's see!

Alright, it still looks similar to the picture we got for the full 2017... Christian is still on the outter rings of our network and bridging toward low centrality nodes. Only difference is that he has a slightly higher centrality value than during the whole year. Needless to say just that semester doesn't learn us much. Time to look at the second semester then.

Ah-Ah! Now we see something new, Christian is now mostly disconnected from the network! He is part of a clique containing him and Michael Bohlender. Looking further at their activity they are indeed focusing almost exclusively on Kube. Michael was in fact one of those low centrality nodes Christian was bridging to previously.

So what are we looking at? It seems to be the birth of an insular sub-team in the KDEPIM community. It's technically not a fork since they're working on a specific software but this clique configuration indicates they moved their focus there, they didn't attract the rest of the KDEPIM community to contribute (yet?) and they stopped contributing completely to the wider KDEPIM effort (at least for the time frame we've been looking at). The community got split there.

Now we could leave it at that and consider it like a detail... or... if you're like me and want not only to produce those graphs and metrics but wonder if some of those things could be turned into useful tools for community stewardship in general and the Community Working Group in particular, you won't stop there.

From the two networks above and the one I produced the last time it's clear that we need to deal with time... From a single network we freeze the time and get a configuration for a given period. If we ever want to see that something like the clique we saw appearing here can be detected we need a less static view.

For the time being, we will look at individual centrality of a contributor over time. For that we will get their monthly centrality value in the network over a three months sliding window (previous month, current month and next month). Since it's also interesting to have an idea of the activity of the contributor over the time period, we'll also plot the normalized monthly activity of the contributor. Finally, since centrality is dependent on the team size, we'll plot the normalized team size on the period.

Regarding that last plot, a few more words because it's a fairly important one that Volker Krause helped me realize during the KDEPIM sprint because of his own plots and discussing them with him, unfortunately it's also what makes the centrality tricky to read. The centrality value of a node is a value between 0 and 1, if a node is not connected at all it gets a 0 if a node is connected to all other nodes it gets a 1. So obviously, if the team is large you need way more connections to get a high centrality than in a small team.

Corollary of the point above is that centrality values variation are meaningful only during a stable team size. If we're a period of decreasing or increasing team size variations on a centrality can occur for a node even though it would have maintained the exact same connections! And that's why we have the third plot on the team size in the graphs below to get an idea on how much trust we can put in the variation of the centrality plot.

Alright, with that out of the way (although it'll keep haunting us while reading those plots), now it's time to explore those plots. We won't look only at one, I think it's a good idea to look at more than one contribution pattern before coming back to Christian. To get there and keep those plots somewhat comparable I'll drastically expand the time period we'll look at, instead of looking at 2017 only, we'll go all the way back to 2007! This way we can see more of KDEPIM's history and get patterns also from old timers. Let's start!

So first thing first, we see the evolution of the team size in KDEPIM on the last ten years. Interestingly we see the decrease that Paul Adams was pointing out in his last Akademy talk... but it's not reaching the ground and it looks like it stabilized at least since 2014. Is it the case for the whole of KDE? Does the commit activity look the same globally? Clearly questions I'll have to investigate as well, it never ends! :-)

In any case this variation on team size seems to indicate that we can look at the centrality variations from 2007 to end of 2009 or from 2014 to the end of 2017 somewhat safely. Of course the team size keeps varying but it's more noise than a real trend so it should be fine overall.

With that in mind, what we can see from Till is a former core contributor who slowly stopped to contribute. This is crystal clear just from his activity plot and the centrality plot as expected follows the same pattern. It's indeed less correlated with his activity in the 2010 to 2012 period but that's to be expected with the downward trend in team size.

This second graph is now about Volker Krause. We can see the top activity he had during 2009 and because the team size was large at the time it required such a high activity for him to have his centrality spike as well. The mystery spike of September 2016 is what prompted the display of the team size plot. He had only a very tiny activity that month which generated a surge in centrality... well it turns out that even though he did only a hand full of commits some of them were on build system files which tend to be touched by others and because of the smaller team size than in 2009 the variation get amplified.

So now that we're done with our two "example" core contributors... let's get back in the territory of the very active contributors of the past year...

Let's look at Laurent in this third graph, clearly he has been contributing to KDEPIM for a long time but overall not on a very high volume. It really started to increase around 2012 so I guess that's when he slowly took over maintainership of KMail. As expected that's when we see his centrality raising as well as he was getting involved with more and more components of KDEPIM. Of course it's slightly amplified by the decrease of team size over the 2012 - 2014 period but he kept getting more central even after that.

And finally, this fourth graph gets us back to Christian. Clearly he joined KDEPIM at the end of 2010, from that point on he looks like any other future contributor with increased activity correlating with increased centrality (watch out for the decrease of team size until 2014 which amplifies a bit the effect on that period). Then during 2014 we have a somewhat stable centrality and activity. Some noise but nothing out of the ordinary over a year. It gets interesting after that though. During 2015 we see his activity increasing again but at the same time his centrality starts dropping a first time. It then stays somewhat stable while his activity spikes. And toward the end of 2017 centrality completely drops. This is a very different pattern from all the other contributors we looked at.

In my opinion, the interesting observation is that by looking at the contributor network, we see the clique only appearing at the second semester of 2017, but, on the centrality graph we see this pattern of increasing activity with decreasing centrality starting in 2015! Two years before the community split is visible.

Now the question I have, and I think it'll be a tough one so I might leave it unanswered for a little while. Could we detect this kind of pattern early? Could we detect without too much false positive (even though there always will be some of them)?

I think it's important to think about that because in that particular case, assuming we'd have such a tool, the Community Working Group would have been warned of a team split to come and maybe step in to see if they could save the situation. Currently our Community Working Group is mostly working in reactive mode since they talk to people when a conflict emerges, with such a tool they could also try to be proactive and check on a team if the "increasing activity with decreasing centrality" pattern emerges. I think it would be nice if they could do this and talk to people before too many feelings were hurt.

It'll take time to get there, if at all. But I think it's worth looking into.


Разместил: Planet KDE | Дата: 22.04.2018 | Прочитано: 333 | Раздел: System & Utilities   

Рейтинг статьи

Средняя оценка: 0.00/0Средняя оценка: 0Всего голосов:0

Хорошо Нормально Пойдёт Плохо

Смотрите также связанные темы

15.09.2010 HPC Application Performance on ESX 4.1: NAMD
HPC Application Performance on ESX 4.1: NAMD This is the second part in an on-going series on exploring performance issues of virtualizing HPC applications. In the first part we described the setup and considered memory bandwidth. Here we look at network latency in the context of a single application. Evaluating the effect of network latency in general is far more difficult since HPC apps range from ones needing micro-second latency to embarrassingly-parallel apps that work well on slow networks. NAMD is a molecular dynamics code that is definitely not embarrassingly parallel but is known ...
18.11.2010 VMworld 2010 Online Sessions
VMworld 2010 Online Sessions Now that VMworld 2010 has concluded, it's time to digest and consume sessions that were offered.  If you attended VMworld 2010 in either San Francisco or Copenhagen, you have been granted full access.  If you were not an attendee, you will need a VMworld 2010 Subscription.  However, VMworld 2010 General Sessions + Super Sessions AND all content from previous VMworld conferences is free to all visitors. All Super Sessions and Breakout Sessions that were captured from VMworld 2010 in San Francisco have been posted.  Selected Breat...
01.12.2010 HPC Application Performance on ESX 4.1: Memory Virtualization
HPC Application Performance on ESX 4.1: Memory Virtualization This is the third part in an ongoing series on exploring performance issues of virtualizing HPC applications. In the first part, we described the setup and considered pure memory bandwidth using Stream. The second part considered the effect of network latency in a scientific application (NAMD) that ran across several virtual machines.  Here we look at two of the tests in the HPC Challenge (HPCC) suite:  StarRandomAccess and HPL. While certainly not spanning all possible memory access patterns found in HPC apps, these two tests ...
"New platform offers unified management of all acoustics in the car, enabling customers to reduce the cost, complexity, and time-to-production of audio signal-processing systems. Las Vegas, International CES 2016, LVCC North Hall, Booth 325 - January 6 - QNX Software Systems Limited, a subsidiary of BlackBerry Limited, today announced the new QNXreg; Acoustics Management Platform AMP, a comprehensive solution that allows automakers to enhance the audio and acoustic experience for drivers and passengers, while reducing system costs and complexity.Modern vehicles contain multiple acoustic and au...
21.09.2016 Kexi 3 Beta 1 + libs
Cool, Kexi 3.0.0 Beta 1 and related libraries have landed, ready for testing and packaging. Please find downloads and change logs at This time the release got automated a bit more.
04.09.2016 QtCon Opens In Berlin
Long-time Slashdot reader JRiddell writes: A unique coming together of open source communities is happening in Berlin over the next week. QtCon brings together KDE, Qt, VLC and FSF-E to discuss free software, open development, community management and proprietary coding.
12.10.2016 Resurrecting Yakuake
No use in beating around the bush: Yakuake is currently not in great shape. While the codebase made the jump to KDE Frameworks 5 quite early, it took a long time to get releases out, and the latest still suffers from some annoying, if minor, regressions and bugs.
24.12.2016 Fedora and KDE/spin's treatment - Discussion
I think it's important that the Fedora KDE / Spins Community speak out about how Fedora treats KDE and other spins. Given Fedora is about to have FESCo election, now is the perfect time to get community feedback on what candidates think.
19.10.2017 Top 7 open source terminal emulators for Linux
Do you spend a good amount of your time at the command line? These terminal emulators will help make it a better experience. Are you a system administrator, Linux power user, or someone who just spends a lot of time at the command line? Chances are your choice of terminal emulator says something about you.
21.01.2018 About Babe
I've been working on a small music player named Babe for a while now, it started as an idea of a bare simple music player, and as the time has passed it has become a project I hope to expand beyond a simple music player. Last year I presented the project to the KDE community at Akademy 2017 that took place in Almeria-Spain, I wanted to highlight back then the idea of a multimedia desktop application that was aware of its content by making use of the wide knowledge that could be found on the internet, by making use of a music information retrieval system called Pulpo together with AI techni...
Нет комментариев. Почему бы Вам не оставить свой?
Вы не можете отправить комментарий анонимно, пожалуйста зарегистрируйтесь.
Google Search


Топ Новостей
1: Fedora and KDE/spin\'s treatment - Discussion
Просмотров - 1416

2: KDE\'s Kirigami 2.0 Framework for Convergent UIs Enters Beta with New Features
Просмотров - 637

3: Akonadi/KMail issues on Tumbleweed?
Просмотров - 630

4: Netrunner Desktop 16.09 "Avalon" Linux OS Is Out with Kernel 4.7, KDE Plasma 5.7
Просмотров - 599

5: KDevelop 5.0.2 released for Windows and Linux
Просмотров - 585

6: Interview with Esfenodon
Просмотров - 562

7: Offline Vaults for an extra layer of protection
Просмотров - 532

8: 3.0 Pre-alpha 3 is out!
Просмотров - 519

9: Multi-screen woes in Plasma 5.7
Просмотров - 513

10: Embrace Open Source culture: the 5 common transformations.
Просмотров - 502

11: GSoC Update 1: The Beginning
Просмотров - 498

12: fresh breeze for Ubuntu
Просмотров - 495

13: [TORRENT] chakra-2016.02-ian-x86_64.iso
Просмотров - 483

14: Qt SCXML and State Chart Support in Qt Creator
Просмотров - 469

15: Interview with Neotheta
Просмотров - 466

Google 120X240

Главная | Actual Topics | Статьи | Обратная связь | Guest Book
Генерация: 1.462 сек. и 13 запросов к базе данных за 1.404 сек.
Powered by SLAED CMS © 2005-2007 SLAED. All rights reserved.