Are open source projects governed by rich clubs?

The network of collaborations in an open source project can reveal relevant emergent properties that influence its prospects of success.

In our recent joint work with the Open University of Catalunya / ICREA, we analyze open source projects to determine whether they exhibit a rich-club behavior, that is a phenomenon where contributors with a high number of collaborations (i.e., strongly connected within the collaboration network) are likely to cooperate with other well-connected individuals.

ownCloud-open-source-accessibilityThe presence or absence of a rich-club has an impact on the sustainability and robustness of the project. In fact, if a member of the rich club leaves the project, it is easier for other members of the rich club to take over. Less collaborations would require more effort from more users.

The work has been presented at OpenSym 2019, the 15th International Symposium on Open Collaboration, in Skövde (Sweden), on August 20-22, 2019.

The full paper is available on the conference Web Site (or locally here), and the slides presenting our results are available on Slideshare:

For this analysis, we build and study a dataset with the 100 most popular projects in GitHub, exploiting connectivity patterns in the graph structure of collaborations that arise from commits, issues and pull requests. Results show that rich-club behavior is present in all the projects, but only few of them have an evident club structure.

For instance, this network of contributors for the Materialize project seems to go against the open source paradigma. The project is “owned” by very  few users:

richclubEstablished in 2014 by a team of 4 developers, at the time of the analysis it featured 3,853 commits and 252 contributors. Nevertheless, the project only has two top contributors (with more than 1,000 commits), which belong to the original team, and no other frequent contributors.

For all the projects, we compute coefficients both for single source graphs and the overall interaction graph, showing that rich-club behavior varies across different layers of software development. We provide possible explanations of our results, as well as implications for further analysis.

Alcuni esempi di progetti universitari

Potete trovare alcuni esempi di progetti universitari legati a sviluppo software e ingegneria del software sul seguente sito di Andrea Radice (ex studente Polimi):

Some examples of software engineering and software development courses, courtesy of Andrea Radice, former Polimi student:

Pattern-Based Specification of Crowdsourcing Applications – ICWE 2014 best paper

I’m really proud to announce that our paper “Pattern-Based Specification of Crowdsourcing Applications” has received the BEST PAPER award at ICWE 2014 (International Conference on Web Engineering), held in Toulouse in July 2014. The paper was authored by Alessandro Bozzon, Marco Brambilla, Stefano Ceri, Andrea Mauri, and Riccardo Volonterio.

The work addresses the fact that in many crowd-based applications, the interaction with performers is decomposed in several tasks that, collectively, produce the desired results.
A number of emerging crowd-based applications cover very different scenarios, including opinion mining, multimedia data annotation, localised information gathering, marketing campaigns, expert response gathering, and so on.
In most of these scenarios, applications can be decomposed in tasks that collectively produce their results; Tasks interactions give rise to arbitrarily complex workflows.

In this paper we propose methods and tools for designing crowd-based workflows as interacting tasks.
We describe the modelling concepts that are useful in such framework, including typical workflow patterns, whose function is to decompose a cognitively complex task into simple interacting tasks so that the complex task is co-operatively solved.
We then discuss how workflows and patterns are managed by CrowdSearcher, a system for designing, deploying and monitoring applications on top of crowd-based systems, including social networks and crowdsourcing platforms. Tasks performed by humans consist of simple operations which apply to homogeneous objects; the complexity of aggregating and interpreting task results is embodied within the framework. We show our approach at work on a validation scenario and we report quantitative findings, which highlight the effect of workflow design on the final results.

Here are the slides presented by Alessandro Bozzon during the ICWE conference:


Here is Alessandro Bozzon presenting:

and here is the picture of the actual award:

ICWE 2014 Best Paper Award Certificate to Pattern-Based Specification of Crowdsourcing Applications. Bozzon, Brambilla, Ceri, Mauri, Volonterio

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IFML 1.0: Interaction Flow Modeling Language approved by the OMG

After three years of work, IFML 1.0 is finally approved by the OMG!
The Interaction Flow Modeling Language was actually adopted one year ago, in March 2013, as Beta specification by the Object Management Group (OMG). Since then, the IFML Finalization Task Force worked hard to bring the specification to perfection.

The Object Management Group (OMG) Architecture Board approves the new IFML 1.0 standard on March 2014 in Reston, VA
The OMG Architecture Board gathered for approval of IFML. Among others, you can see Andrew Watson (OMG), Juergen Boldt (OMG), and representatives of IBM, 88Solutions, Adaptive, Fujitsu,  PrismTech and others.

Along the path, we got valuable feedback from implementors of the standard, spanning DSL tool vendors implementing the notation, UML tool vendors implementing the UML profile, and our own developers at WebRatio implementing the commercial industry-strenght modeling tool and code generators, as well as a bunch of opensource IFML editors. We also got feedback from WebRatio customers, which contributed to improve the language notation too.

All this summed up to 77 issues formally submitted to the OMG and subsequently addressed by the task force. The specification document, as well as the machine readable files (XMIs) have been cleaned up and prepared for final publication.
As a last step, the finalized version of the standard has been presented at the ADTF and at the Architecture Board of the OMG during the March technical meeting in Reston, VA, USA.
Version 1.0 is now officially adopted by the OMG. It’s just a matter of a few weeks before the final, copyedited version of the specification will be officially available on the OMG servers.
For documentation purposes, here is a snapshot of the program
Meanwhile, you can have a look at the sneak preview of the final version of IFML. Further details are available on the official site.

As Stefano Butti, CEO of WebRatio said, IFML is one of the three biggest leaps in WebRatio history (together with the move to the US and the selection of WebRatio as Gartner Cool Vendor). Other vendors have already declared interest and/or started developing some modeling solution based on IFML. We look forward to wide adoption of this new standard, thanks also to the integration with other modeling aspects such as business modeling (with BPMN) and system modeling (with UML, SoaML, SysML, …)!

At the Reston event we also gave away the first copies ever of the very nice IFML Cheat Sheet (or Quick Reference Guide) prepared by WebRatio based on the official specification document.
The cheat sheet is available for free on the learning portal of WebRatio.

IFML CheatSheet - Quick Reference Guide and examples
The IFML cheat sheet: Quick Reference Guide and Examples (on the back side, not shown here).

Here is a small photo gallery of the event location, the WebRatio booth and the program of the AB plenary where IFML was adopted.

WebRatio boothOMG AB agenda for March 2014


To keep updated on my activities you can subscribe to the RSS feed of my blog or follow my twitter account (@MarcoBrambi).

5th MDA and Agile Modeling Forum, Milano, Sept 30, 2010 – Afternoon Session

In the afternoon session of the 5th MDA and Agile Modeling Forum I got the following messages:

Fabrizio Gheller (Altran)
Need and advntages of applying a stability index to business objects to obtain better overall performances of processes.

Pierfranco Ferronato (
Wrong perspectives on agile development:

  • Agile as an excuse for avoiding planning and documentation
  • Programers are the only knowledgeable of what happens at the business level
  • Resource lock-in: if that guy leaves, we are dead. He is the only one who knows!

Sometimes there’s the need of joining business and IT, sometimes of splitting them: IT people should not talk business, and business ones should not talk IT .
UML is not a DSL, it’s a NDL: No Domain Language.Spaghetti modelling is not much better than spaghetti programming, and a tool or standard method per se will not solve your problems.
The problem should be split in:

  • configure the business [IT independent]: parameters and success metrics
  • model the business [IT independent]: steps and activities
  • support the business [IT dependent]: new services and semantics

The developer will not write specific code any more, he will write templates.

Roberto Pozzi (IBM Rational)
The usual risk is separation between models and implementations. Diversified tools and languages are needed for allowing communication between business and IT and between planning and solution delivery, down to alignment of the infrastructures that support business services.
Rational System Architect is a toolsuite that provides different modeling views to the enterprise architecture design.
Objective criteria must be defined to keep activities aligned with the objectives. Risk analysis and metrics should be applied to model driven design too, to allow governance of the portfolio of projects.
Eventually, a unified and unique repository should be there for allowing search and reuse of all the assets. Metamodels should guide their classification (as from the “Rational Common Modeling Platform” vision).
IBM is not yet at modeling execution, but for sure model simulation is fully achieved.

Paolo Miola (Tibco)
He discussed the lessons learned from applying Tibco and bp reengineering to a large-scale bpm and bam scenario for Crédit Lyonnais (LCL) part of the Crédit Agricole Group (6,000 backoffice users and 60,000 documents managed daily).

  • First phase: application of BPM and BAM to the scenario
  • Second phase: applying rule-based dynamic job assignment based on workload, context and expertise of the various executors (geographically distributed)

 The objectives are:

  • process visibility: understanding and coding the processes
  • process governance and unified management
  • flexibility
  • resource optimization (in the example scenario: 75% of human resources were spared and reallocated to more core activities)

The next wave for Tibco is predictive behaviour of systems: the two-second advantage: “a little bit of information beforehand is more valuable than all of the information after the event”.

Ernesto Damiani (UniMi)
Interestingly enough, on a set of 200 companies in Lombardy, a lot claim the have or want to have BPM solutions and BPM capabilities, but then 60% of them declare a time-to-implementation of more than 6 months for any BP change (= no flexibility) and 80% declare that no measure of productivity improvement after bpm automation is monitored.
Furthermore, typically, IT division and CIOs have no role in BPM (not only at the modeling level, but also at the procurement and technical level for enactment of models). Effect is that IT performs only support activity to modeling, and costs are allocated to the IT division, while decision is driven by high management.