Coordinating Asynchronous Actors – from Tuple Spaces to Tweetflows

The coordination of asynchronous actors has always been a major problem in distributed systems and parallel computing. About 20 years ago, David Gelernter and Nicholas Carriero have introduced the coordination language Linda. The most important difference to existing approaches was that they treated the coordination problem seperately from the computation problem. Linda implementations offer the [...]

Tweetflow Natural Language Generation

Hi, My Praktikums-Topic is about creating an Android client for generating natural sentences out of Tweetflows. As you might have read already, Tweetflows are used to create mobile workflows. Tweetflows should be useable by humans, but actually they have a quite technical syntax. If you are not familiar with it and may have not a [...]

Quick Start With StatusNet

In this blog entry I want to talk about the StatusNet server and how you can write plugins for it. In my practical work for the DSG I used StatusNet to write a basic Tweetflow Engine (specification) which handles variables and offers a restful interface. StatusNet is an open source application written in PHP which [...]

“Simple” XML serialization

For our project, the graphical Tweetflow editor for Android, we also wanted to implement the functionality to save created Tweetflows and reopen them later. Therefore we had to find a possibility to save our plain old Java object (POJOs) on the devices storage or in a database and to recreate them afterwards. After some research [...]


As I’m doing my Projektpraktikum and the Bachelor thesis here at the DSG I’ll give you an introduction about the topic. In short, I’ll create an Android App which receives Tweets from a StatusNet server, which is an open-source Twitter server, and provides means to filter them regarding to a user defined pattern. The server [...]

Tweetflows in Action – See how Tweetflows work

Migration of .net Workflows between different hosts

As part of my master thesis on “cloud-based adaptations of service composition hostings” the .net WCF class WorkflowPersistenceService prooved as a promising tool for workflow migrations. class AdaptationPersistenceService: WorkflowPersistenceService { WorkflowAdaptationProxy wap = new WorkflowAdaptationProxy(); protected override void SaveWorkflowInstanceState(Activity rootActivity, bool unlock) { Guid instanceId = (System.Guid)rootActivity.GetValue(Activity.ActivityContextGuidProperty); Console.WriteLine(“Saving Instance {0} “, instanceId); byte[] rootBytes = [...]

Lightweight Service Invocation using Twitter

Lightweight Service Invocation over Twitter can provide benefits through reuse of existing social structures and crowdsourcing opportunities. This article describes an example scenario and the corresponding tweetflow primitives that could be used to control publication, binding, search, invocation, coordination and monitoring of computer-provided as well as human-provided services.