Software product lines represent perhaps the most exciting paradigm shift in software development since the advent of high-level programming languages. Nowhere else in software engineering have we ...seen such breathtaking improvements in cost, quality, time to market, and developer productivity, often registering in the order-of-magnitude range. While the underlying concepts are straightforward enough building a family of related products or systems by planned and careful reuse of a base of generalized software development assets the devil can be in the details, as successful product line practice can involve organizational change, business process change, and technology change. The authors ideally combine academic research results with industrial real-world experiences, thus presenting a broad view on product line engineering so that both managers and technical specialists will benefit from reading it. After presenting a common framework for the description of the industrial case studies, they capture the wealth of knowledge that eight companies have gathered during the introduction of the software product line engineering approach in their daily practice. After reading this book, you will understand all the relevant aspects, regarding business, architecture, process, and organizational issues, of applying software product line engineering. If you consider using a product line approach in your organization, or if you want to improve your current practices you will find a rich set of useful information at your fingertips from practitioners to practitioners.
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2.
A framework for clustering uncertain data Schubert, Erich; Koos, Alexander; Emrich, Tobias ...
Proceedings of the VLDB Endowment,
08/2015, Volume:
8, Issue:
12
Journal Article
Peer reviewed
The challenges associated with handling uncertain data, in particular with querying and mining, are finding increasing attention in the research community. Here we focus on clustering uncertain data ...and describe a general framework for this purpose that also allows to visualize and understand the impact of uncertainty---using different uncertainty models---on the data mining results. Our framework constitutes release 0.7 of ELKI (http://elki.dbs.ifi.lmu.de/) and thus comes along with a plethora of implementations of algorithms, distance measures, indexing techniques, evaluation measures and visualization components.
Blends of two long-chain branched polypropylenes (LCB-PP) and five linear polypropylenes (L-PP) were prepared in a single screw extruder at 240 °C. The two LCB-PPs were self-created via reactive ...extrusion at 180 °C by using dimyristyl peroxydicarbonate (PODIC C126) and dilauroyl peroxide (LP) as peroxides. For blending two virgin and three recycled PPs like coffee caps, yoghurt cups and buckets with different melt flow rate (MFR) values were used. The influence of using blends was assessed by investigating the rheological (dynamic and extensional rheology) and mechanical properties (tensile test and impact tensile test). The dynamic rheology indicated that the molecular weight as well as the molecular weight distribution could be increased or broadened. Also the melt strength behavior could be improved by using the two peroxide modified LCB-PP blends on the basis of PODIC C126 or PEROXAN LP (dilauroyl peroxide). In addition, the mechanical properties were consistently enhanced or at least kept constant compared to the original material. In particular, the impact tensile strength but also the elongation at break could be increased considerably. This study showed that the blending of LCB-PP can increase the investigated properties and represents a promising option, especially when using recycled PP, which demonstrates a real "up-cycling" process.
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Long-chain branching (LCB) is known as a suitable method to increase the melt strength behavior of linear polypropylene (PP), which is a fundamental weakness of this material. This enables the ...modification of various properties of PP, which can then be used-in the case of PP recyclates-as a practical "upcycling" method. In this study, the effect of five different peroxides and their effectiveness in building LCB as well as the obtained mechanical properties were studied. A single screw extruder at different temperatures (180 and 240 °C) was used, and long-chain branched polypropylene (PP-LCB) was prepared via reactive extrusion by directly mixing the peroxides. The peroxides used were dimyristyl peroxydicarbonate (PODIC C126), tert-butylperoxy isopropylcarbonate (BIC), tert-Butylperoxy 2-ethylhexyl carbonate (BEC), tert-amylperoxy 2-ethylhexylcarbonate (AEC), and dilauroyl peroxide (LP), all with a concentration of 20 mmol/kg. The influence of the temperature on the competitive prevalent reactions of degradation and branching was documented via melt mass-flow rate (MFR), rheology measurements, and gel permeation chromatography (GPC). However, via extensional rheology, strain hardening could be observed in all cases and the mechanical properties could be maintained or even improved. Particularly, PODIC C126 and LP signaled a promising possibility for LCB in this study.
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Apart from objective exam results, the overall feeling of preparedness is important for a successful transition process from being a student to becoming a qualified doctor. This study examines the ...association between self-assessed deficits in medical skills and knowledge and the feeling of preparedness of junior doctors in order to determine which aspects of medical education need to be addressed in more detail in order to improve the quality of this transition phase and in order to increase patient safety.
A cohort of 637 doctors with up to two years of clinical work experience was included in this analysis and was asked about the overall feeling of preparedness and self-assessed deficits with regard to clinical knowledge and skills. Three logistic regression models were used to identify medical skills which predict the feeling of preparedness.
All in all, about 60% of the participating doctors felt poorly prepared for post-graduate training. Self-assessed deficits in ECG interpretation (aOR: 4.39; 95% CI: 2.012-9.578), treatment and therapy planning (aOR: 3.42; 95% CI: 1.366-8.555), and intubation (aOR: 2.10; 95% CI: 1.092-4.049) were found to be independently associated with the overall feeling of preparedness in the final regression model.
Many junior doctors in Germany felt inadequately prepared for being a doctor. With regard to the contents of medical curricula, our results show that more emphasis on ECG-interpretation, treatment and therapy planning and intubation is required to improve the feeling of preparedness of medical graduates.
Long-chain branching (LCB) with peroxydicarbonates (PODIC) is known as a suitable post-reactor process to introduce strain-hardening behaviour and an increase of melt strength to a linear ...polypropylene (PP). This opens up new possibilities for processing and therefore application. Especially in the case of adding value to PP post-consumer waste, LCB is a promising approach. LCB takes place by a combination of chain scission and recombination after radical activation of the PP macromolecule. However, chemical modification of post-consumer waste is challenging because of the inhomogeneous composition and the manifold number of PP grades. The influence of the molar mass of the linear PP precursor on this reaction was studied with different PP grades ranging from extrusion grade to injection moulding grade. To exclude side effects, all PP grades had similar polydispersity indices. A PP with higher molar mass undergoes significant chain scission during the LCB process compared to a PP with low molar mass for injection moulding. Therefore, the two grades differ significantly in their branching number, which influences their behaviour in elongational flow.
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The effects of zinc and sodium hydroxide concentrations in an alkaline non-cyanide zinc bath on the electrodeposition characteristics of zinc deposits are systematically investigated. Using ...microstructural and phase analyses of specimens with specifically designed geometries, the study indicates that the bath formulations critically control the electrogalvanizing characteristics and affect the coating surface morphology, deposition rate, throwing power, coating uniformity, and residual stresses developed during and after electrogalvanizing. The coatings produced from baths with a moderate Zn-to-NaOH ratio of 0.067–0.092 appear to provide uniform and compact deposits, moderately high deposition rate, and relatively low residual stresses.
•SPASS-meter, a novel tool for online monitoring of components of software systems.•Components can be defined declaratively through interfaces (annotations or external).•Condenses measurement data at ...runtime=basis for adaptive systems.•Supports wide range of Java-platforms (incl. Android) and resource types.•Competitive efficiency (cmp. to Kieker, OpenCore) despite additional processing.
Monitoring resource consumptions is fundamental in software engineering, e.g., in validation of quality requirements, performance engineering, or adaptive software systems. However, resource monitoring does not come for free as it typically leads to overhead in the observed program. Minimizing this overhead and increasing the reliability of the monitored data is a major goal in realizing resource monitoring tools. Typically, this is achieved by limiting capabilities, e.g., supported resources, granularity of the monitoring focus, or runtime access to results. Thus, in practice often several approaches must be combined to obtain relevant information.
We describe SPASS-meter, a novel resource monitoring approach for Java and Android Apps, which combines these conflicting capabilities with low overhead. SPASS-meter supports a large set of resources, flexible configuration of the monitoring scope even for user-defined semantic units (components), runtime analysis and online access to monitoring results in a platform-independent way. We discuss the concepts of SPASS-meter, its architecture, realization and validation, the latter in terms of case studies and an overhead analysis based on performance experiments with SPASS-meter, OpenCore and Kieker. SPASS-meter provides a detailed view of the runtime resource consumption at reasonable overhead of less than 3% processing power and 0.5% memory consumption in our experiments.
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