H.-Christian Estler

Learn More
This paper presents a new general-purpose algorithm for exact solving of combinatorial many-objective optimization problems. We call this new algorithm the guided improvement algorithm . The algorithm is implemented on top of the non-optimizing relational constraint solver Kodkod [24]. We compare the performance of this new algorithm against two algorithms(More)
In globally distributed software development, does it matter being agile rather than structured? To answer this question, this paper presents an extensive case study that compares agile (Scrum, XP, etc.) vs. structured (RUP, waterfall) processes to determine if the choice of process impacts aspects such as the overall success and economic savings of(More)
Software projects have crossed seas and continents looking for talented developers, moving from local developments to geographically distributed projects. This paper presents a case study analyzing the effect of distribution and time zones on communication in distributed projects. The study was performed in a university course during two semesters, where(More)
The advent of Massive Open Online Courses makes it essential to develop tools and techniques that automatically support computer science students in solving programming assignments. Complementing existing tools for automatically checking the correctness of students' programs, we have developed and evaluated an incremental hint system for programming(More)
A cDNA encoding a serotonin transporter (5-HTT) in the human dorsal raphe nucleus was isolated and sequenced using cross-species amplification of human 5-HTT partial cDNA by the polymerase chain reaction (PCR) and the RACE-PCR procedure, designed for rapid amplification of 3′ and 5′ cDNA ends. The cDNA contains an open reading frame encoding a hydrophobic(More)
Tumor necrosis factor (TNF) has been shown to mediate lipopolysaccharide-induced neutrophil adhesion to liver sinusoidal endothelium in vivo. Female NMRI mice received either 5 micrograms lipopolysaccharide (R595) per animal alone (model A) or together with 116 mumol D-galactosamine (model B). One hour after injection, TNF activity in the serum was(More)
As software development becomes an increasingly collaborative effort, traditional development tools have to be extended to support seamless collaboration while minimizing the chances of conflicts. This paper describes Cloud Studio, a collaboration framework that integrates a fine-grained software configuration management model and a real-time awareness(More)
Refactorings are changes made to programs, models or specifications with the intention of improving their structure and thus making them clearer, more readable and re-usable. Refactorings are required to be behaviour-preserving in that the external behaviour of the program/model/specification remains unchanged. In this paper we show how a simple type of(More)
Software development environments (IDEs) have not followed the IT industry’s inexorable trend towards distribution. They do too little to address the problems raised by today’s increasingly distributed projects; neither do they facilitate collaborative and interactive development practices. A consequence is the continued reliance of today’s IDEs on(More)
Refactorings are systematic changes made to programs, models or specifications in order to improve their structure without changing the externally observable behaviour. We will examine how a constraint solver (the Alloy Analyzer) can be used to automatically check if refactorings, applied to a formal specification (written in Z), meet this requirement.(More)