Browsing by Author "Keller, Fabian"

Now showing 1 - 3 of 3

Open Access
Analysis of slicing-tools for fused deposition modeling 3D-printers and comparison of different printers
(2014) Bugdayci, Halil; Grunert, Jonas; Keller, Fabian
The term 3D printer refers to machines capable of additive manufacturing, which means creating objects by sequential layering. Additive manufactured objects can be used in the whole product life cycle, from rapid prototyping through small series production up to full production. In addition to the hardware itself it is necessary to use tools and applications like "slicing tools", post-production adjustments, process models and testing and verifying scenarios. With slicing tools it is possible to convert digital 3D models into printing instructions for 3D printers. The general approach is: The model is cut into horizontal slices which are then used to create extrusion paths similar to milling paths in the traditional CNC field, which are then being filled with material, mostly plastic material. Commonly the amount of extruded material is being calculated subsequently (price and time estimate). The goal of this study is to compare available slicing tools on multiple 3D printers under defined aspects using different configurations. The main contributions of this study are: 1. Collecting methods and tools to judge print results, 2. Analysis of the available slicing tools and 3D printers with appropriate tests and comparisons and 3. Evaluating the slicing tools using the analysis as solid foundation.
Open Access
Introducing performance awareness in an integrated specification environment
(2016) Keller, Fabian
With an increase in software complexity and modularization to create large software systems and software product lines it is increasingly difficult to ensure all requirements are met by the built system. Performance requirements are an important concern to software systems and research has developed approaches being capable of predicting software performance from annotated software architecture descriptions, such as the Palladio tool suite. However, the tooling when moving between specification, implementation and verification phase has a gap as the tools are commonly not linked, leading to inconsistencies and ambiguities in the produced artifacts. This thesis introduces performance awareness into the Integrated Specification Environment for the Specification of Technical Software Systems (IETS3), which is a specification environment aiming to close the tooling gap between the different lifecycle phases. Performance awareness is introduced by integrating existing approaches for software performance prediction from the Palladio tool suite and extending them to cope with variability-aware system models for software product lines. The thesis includes an experimental evaluation showing that the developed approach is able to provide performance predictions to users of the specification environment within 2000 ms for systems of up to 20 components and within 8000 ms for systems of up to 30 components.
Restricted
Systematic architecture level fault diagnosis using statistical techniques
(2014) Keller, Fabian
In the past various spectrum-based fault localization (SBFL) algorithms have been developed to pinpoint a fault location given a set of failing and passing test executions. Most of the algorithms use similarity coefficients and have only been evaluated on established benchmark programs like the Siemens set or the space program from the Software-artifact Infrastructure Repository. In addition to that, SBFL has not been applied by developers in practice yet. This study evaluates the feasibility of applying SBFL to a real-world project, namely AspectJ. From an initial set of 110 manually classified faulty versions, a maximum of seven bugs can be found after examining the 1000 most suspicious lines produced by various SBFL techniques. To explain the result, the influence of the program size is examined using different metrics and evaluations. In general, the program size has a slight influence on some metrics, but is not the primary explanation for the results. The results seem to originate from the metrics currently used throughout the research community to assess SBFL performance. The study showcases the limitations of SBFL with the help of different performance metrics and the insights learned during manual classification. Moreover, additional performance metrics that are better suited to evaluate the fault localization performance are proposed.