Should I Bug You? Identifying Domain Experts in Software Projects Using Code Complexity Metrics

In any sufficiently complex software system there are experts, having a deeper understanding of parts of the system than others. However, it is not always clear who these experts are and which particular parts of the system they can provide help with. We propose a framework to elicit the expertise of developers and recommend experts by analyzing complexity measures over time. Furthermore, teams can detect those parts of the software for which currently no, or only few experts exist and take preventive actions to keep the collective code knowledge and ownership high. We employed the developed approach at a medium-sized company. The results were evaluated with a survey, comparing the perceived and the computed expertise of developers. We show that aggregated code metrics can be used to identify experts for different software components. The identified experts were rated as acceptable candidates by developers in over 90% of all cases

Navigating Across Non-Navigable Ecore References via OCL

The Eclipse Modeling Framework (EMF) and its meta-meta model Ecore support uni-directional and bi-directional references. It is quite common that references are defined uni-directionally only because of saving storage space or separating meta models, which is problematic when implementing Object Constraint Language (OCL) constraints that require navigation against the direction of uni-directional references. This is essential for certain approaches, e.g., incremental evaluation of OCL constraints on models shown by Altenhofen et al. that is used in SAP's Modeling Infrastructure (MOIN). In this paper, we present an approach that overcomes the aforementioned issue by providing navigation across non-navigable Ecore references via OCL. We further discuss different alternative solutions and briefly describe the realization that was outcome of a project in cooperation with the SAP AG

Query Extension Suggestions for Visual Query Systems Through Ontology Projection and Indexing

Ontology-based visual query formulation is a viable alternative to textual query editors in the Semantic Web domain for extracting data from structured data sources in terms of the skills and knowledge required. A visual query system is at any moment responsible for providing the user with query extension suggestions; however, suggestions leading to empty results are often not useful. To this end, in this article, we first present an approach for projecting OWL 2 ontologies into navigation graphs to be used for query formulation and then a solution where an efficient finite index is used to calculate non-ranked approximated extension suggestions for ontology-based visual query systems using navigation graphs. The results of our experiments suggest that one can efficiently project an ontology into a navigation graph, query it for running an interactive user interface, and suggest query extensions that do not lead to dead-ends

25th annual computational neuroscience meeting: CNS-2016

The same neuron may play different functional roles in the neural circuits to which it belongs. For example, neurons in the Tritonia pedal ganglia may participate in variable phases of the swim motor rhythms [1]. While such neuronal functional variability is likely to play a major role the delivery of the functionality of neural systems, it is difficult to study it in most nervous systems. We work on the pyloric rhythm network of the crustacean stomatogastric ganglion (STG) [2]. Typically network models of the STG treat neurons of the same functional type as a single model neuron (e.g. PD neurons), assuming the same conductance parameters for these neurons and implying their synchronous firing [3, 4]. However, simultaneous recording of PD neurons shows differences between the timings of spikes of these neurons. This may indicate functional variability of these neurons. Here we modelled separately the two PD neurons of the STG in a multi-neuron model of the pyloric network. Our neuron models comply with known correlations between conductance parameters of ionic currents. Our results reproduce the experimental finding of increasing spike time distance between spikes originating from the two model PD neurons during their synchronised burst phase. The PD neuron with the larger calcium conductance generates its spikes before the other PD neuron. Larger potassium conductance values in the follower neuron imply longer delays between spikes, see Fig. 17.Neuromodulators change the conductance parameters of neurons and maintain the ratios of these parameters [5]. Our results show that such changes may shift the individual contribution of two PD neurons to the PD-phase of the pyloric rhythm altering their functionality within this rhythm. Our work paves the way towards an accessible experimental and computational framework for the analysis of the mechanisms and impact of functional variability of neurons within the neural circuits to which they belong

Photoinduzierte N2O-Dissoziation und CO-Oxidation auf MgO-Filmen

As a model system for photochemistry on oxide surfaces, the generation of atomic oxygen by photodissociation of N2O adsorbed on thin MgO films which are grown on Ag(001) has been studied under UHV conditions. The reactivity of the generated atomic oxygen was examined by studying the oxidation of CO. If MgO with adsorbed N2O is irradiated with photons (E = 5.0 eV), TPD spectra show a N2O depletion and generation of N2 (desorbing ≈ 55 K) and atomic oxygen (desorbing recombinatively at ≈ 550 K). An analysis of the photon dose dependence suggests two N2O dissociation pathways on the surface with reaction cross sections of about 10^−19 cm^2: The irradiation with E = 5.0 eV leads to an electron-hole-pair excitation at the edges of the MgO film. Excited electrons are trapped at certain defect sites which lead to localized electrons and localized holes at low coordinated sites. These localized charges can cause a dissociation of nearby adsorbed N2O. The presence of the electron and the hole lead to singly charged atomic oxygen. EPR spectroscopy done in cooperation with the department of Hajo Freund confirmed that the generated atomic oxygen is correlated with a free spin. A site-selective chemistry can be applied with different photon energies. If a photon energy of E = 6.4 eV is used, the reaction cross sections increase to 10^−17 cm^2 which is explained by the increased probability to create a trapped electron: The photoexcitation of MgO films at terrace sites leads to a higher amount of generated electron-hole pairs compared to the photoexcitation at lower coordinated sites. The reaction yield could also be controlled by varying the MgO film preparation: Due to a larger surface roughness for thicker MgO films (which led to more electron traps), UV-induced atomic oxygen generation scales with the MgO film thickness. Irradiation (E = 5.0 eV) of the coadsorbate consisting of CO and atomic oxygen leads to a formation of CO2.Als Modellsystem für Photochemie auf Oxiden wurde in dieser Arbeit die Bildung von atomaren Sauerstoff durch Photodissoziation von N2O-Adsorbaten auf dünnen MgO-Filmen, präpariert auf Ag(001), unter UHV-Bedingungen untersucht. Die Reaktivität des atomaren Sauerstoffs wurde anhand von CO Oxidation überprüft. Nach UV-Bestrahlung zeigen thermische Desorptionsspektren eine Abnahme der ursprünglichen N2O Bedeckung und eine Bildung von N2 (Desorption bei ≈ 55K) und atomaren Sauerstoff (rekombinative Desorption bei ≈ 550 K). Die Photonenabhängigkeit der N2O-Dissoziation läßt sich mit einem Mechanismus bestehend aus zwei Reaktionspfaden beschreiben, deren Querschnitte jeweils ≈ 10^−19 cm^2 sind: UV-Bestrahlung (E = 5.0 eV) führt zu einer Elektronen-Loch- Paar-Anregung an Kanten des MgO-Films. Angeregte Elektronen werden an bestimmten Defekten eingefangen und führen zu lokalisierten Elektronen und Löchern, wodurch in der Nähe adsorbiertes N2O dissoziiert. Durch diese Ladungen entsteht einfach geladener atomarer Sauerstoff, dessen freier Spin durch eine EPR-Studie in Kooperation mit der Abteilung von Hajo Freund nachgewiesen wurde. Oberflächenselektive Chemie kann durch unterschiedliche Photonenenergien realisiert werden. N2O-Dissoziation mit einer Photonenenergie von E = 6.4 eV erhöht die Reaktionsquerschnitte auf 10^−17 cm^2. Die erhöhte Wahrscheinlichkeit, lokalisierte Ladungen zu generieren ist eine Erklärung hierfür: Die Photonenanregung an Terrassen von MgO-Filmen führt zu einer größeren Anzahl an generierten Elektron-Loch-Paaren als die an geringer koordinierten Oberflächenstellen. Auch durch Variation der MgO-Präparation kann die Reaktionsausbeute kontrolliert werden: Da dickere Filme eine rauhere Oberfläche haben und damit mehr Elektronenfallen aufweisen, wächst die UV- induzierte Generation von atomaren Sauerstoff mit der MgO-Filmdicke. Bestrahlung eines Koadsorbats bestehend aus vorher generiertem atomaren Sauerstoff und CO führt zur Bildung von CO2 und bestätigt die Reaktivität des atomaren Sauerstoffs

The number of methylated CpG sites within the MGMT promoter region linearly correlates with outcome in glioblastoma receiving alkylating agents

MGMT-promoter methylation is associated with favorable outcome in glioblastoma. The aim of this study was to determine whether the absolute number of methylated Cytosine-Guanine-dinucleotide-(CpG-)sites within the DMR-2 island of the MGMT-promoter may correlate with outcome in a qualitative or quantitative fashion. In a cohort of newly diagnosed glioblastoma patients treated with stereotactic biopsy or open tumor resection plus concomitant chemoradiotherapy, we assessed MGMT-promoter methylation by methylation-specific polymerase-chain-reaction (MSP). Methylation of the CpG-sites 74-98 within the MGMT-promoter region was additionally analysed by Sanger sequencing, and the total number of methylated CpG-sites was correlated with outcome using proportional hazards models. 215 patients with glioblastoma were identified and stratified per MSP (positive: 53%, negative: 47%). Among MSP-positive tumors, hierarchical clustering identified three subgroups with different methylation rates (median: 80% vs. 52% vs. 47%), indicating a site-dependent methylation propagation. The methylation status of a given CpG-site indicated a neighborhood-dependent methylation propagation. Survival was linearly associated with the cumulative number of methylated CpG-sites. This was particularly true in patients who received at least one adjuvant cycle of temozolomide. Notably, all CpG-sites analyzed contributed similarly to effect size; this enabled a further predictive substratification of MSP-positive tumors with median OS ranging from as low as 17.1~months (< 18 methylated CpG-sites) to as high as 26.2~months (≥ 18 methylated CpG-sites) in the overall cohort. All in all, total number of methylated CpG-sites may correlate with outcome in a linear fashion. Such analysis may therefore add further predictive value to conventional methods of determining the MGMT-promoter status

Steuerliche Entlastungsmöglichkeiten für kleine und mittlere Unternehmen wegen der COVID-19-Pandemie - Kann das Steuersystem Solidarität in der Gesellschaft fördern?

Die Autoren beschäftigen sich mit steuerlichen Erleichterungen für KMU als Reaktion auf die Corona-Krise. Der Aufsatz gibt einen Überblick über mögliche ertragsteuerliche Änderungen bei steuerbelastenden und steuerentlastenden Rechtsvorschriften zur Investitions- und Liquiditätsförderung. Im Lichte der gesellschaftspolitischen Rechtfertigung steuergesetzlicher Normen werden außerdem Anreize zu solidarischem Verhalten als Beitrag des Steuerrechts zur Krisenbewältigung diskutiert

Practical Aspects of Automated Deduction for Program Verification

Software is vital for modern society. It is used in manysafety- or security-critical applications, where a high degree of correctness is desirable. Over the last years, technologies for the formal specification and verification of software -- using logic-based specification languages and automated deduction -- have matured and can be expected to complement and partly replace traditional software engineering methods in the future. Program verification is an increasingly important application area for automated deduction. The field has outgrown the area of academic case studies, and industry is showing serious interest. This article describes the aspects of automated deduction that are important for program verification in practice, and it gives an overview of the reasoning mechanisms, the methodology, and the architecture of modern program verification systems