The Scalability-Efficiency/Maintainability-Portability Trade-off in Simulation Software Engineering: Examples and a Preliminary Systematic Literature Review

Large-scale simulations play a central role in science and the industry. Several challenges occur when building simulation software, because simulations require complex software developed in a dynamic construction process. That is why simulation software engineering (SSE) is emerging lately as a research focus. The dichotomous trade-off between scalability and efficiency (SE) on the one hand and maintainability and portability (MP) on the other hand is one of the core challenges. We report on the SE/MP trade-off in the context of an ongoing systematic literature review (SLR). After characterizing the issue of the SE/MP trade-off using two examples from our own research, we (1) review the 33 identified articles that assess the trade-off, (2) summarize the proposed solutions for the trade-off, and (3) discuss the findings for SSE and future work. Overall, we see evidence for the SE/MP trade-off and first solution approaches. However, a strong empirical foundation has yet to be established; general quantitative metrics and methods supporting software developers in addressing the trade-off have to be developed. We foresee considerable future work in SSE across scientific communities.Comment: 9 pages, 2 figures. Accepted for presentation at the Fourth International Workshop on Software Engineering for High Performance Computing in Computational Science and Engineering (SEHPCCSE 2016

Medical decision support systems

Expertensysteme zur Entscheidungsfindung sind ein Trend in der humanmedizinischen Forschung. Derartige Systeme werden in Zukunft die Arbeit von Medizinern prägen. In dieser Fachstudie werden zunächst einige solcher Systeme, die sich zurzeit in der Entwicklung finden, vorgestellt. Zusätzlich werden Erwartungen und Einschätzungen von Medizinern zu diesen Softwaresystemen dargestellt. Abschließend werden die rechtlichen Anforderungen an ein solches Expertensystem, dessen Hersteller und den Entwicklungsprozess durch den Gesetzgeber präsentiert.The trend in human medicine research is towards decision support systems. Such systems will shape the work of physicians in future. In this subject studie, some of those systems that are currently in development will be presented. In addition, the physicians' expectations and assessments of these software systems are shown. Finally, the legal requirements of a decision support systems, its manufacturer and the development process are depicted

No Emergency Brake: Slow Ocean Response to Abrupt Stratospheric Aerosol Injection

Given the possibility of irreversible changes to the Earth system, technological interventions such as solar radiation management (SRM) are sometimes framed as possible climate emergency brakes. However, little knowledge exists on the efficacy of such disruptive interventions. To fill in this gap, we perform Community Earth System Model 2 (CESM 2) simulations of a SSP5-8.5 scenario on which we impose either gradual early-century SRM to stabilise surface temperatures or a rapid late-century cooling, both realised via stratospheric aerosol injection (SAI). While both scenarios cool Earth’s surface, we find that ocean conditions differ drastically. The rapid-cooling scenario fails to dissipate sub-surface ocean heat content (OHC), ends up in a weaker AMOC state and does not restore an ailing North Atlantic deep convection. Furthermore, the weakened AMOC state mediates the climate response to rapid SAI, thus inducing an interhemispheric temperature asymmetry. Our results advise caution when considering SAI as an emergency intervention

Diagnostic challenges within the Bacillus cereus-group: finding the beast without teeth

The Bacillus cereus-group (B. cereus sensu lato) includes common, usually avirulent species, often considered contaminants of patient samples in routine microbiological diagnostics, as well as the highly virulent B. anthracis. Here we describe 16 isolates from 15 patients, identified as B. cereus-group using a MALDI-TOF MS standard database. Whole genome sequencing (WGS) analysis identified five of the isolates as B. anthracis species not carrying the typical virulence plasmids pXO1 and pXO2, four isolates as B. paranthracis, three as B. cereus sensu stricto, two as B. thuringiensis, one as B. mobilis, and one isolate represents a previously undefined species of Bacillus (B. basilensis sp. nov.). More detailed analysis using alternative MALDI-TOF MS databases, biochemical phenotyping, and diagnostic PCRs, gave further conflicting species results. These cases highlight the difficulties in identifying avirulent B. anthracis within the B. cereus-group using standard methods. WGS and alternative MALDI-TOF MS databases offer more accurate species identification, but so far are not routinely applied. We discuss the diagnostic resolution and discrepancies of various identification methods

Injection Locking and Coupling Large VCSEL Arrays via Diffraction in an External Cavity

Trabajo presentado en el NDSL 2021 (Nonlinear Dynamics in Semiconductor Lasers), celebrado online del 16 al 18 de junio de 2021.Coupled semiconductor lasers are of interest from a fundamental complex systems perspective, as well as for various applications, including brain-inspired computing [1-4]. Coupling or feedback can be realized using different approaches, via integrated photonic circuits [5], optical fiber networks [6], or free-space optical setups [7,8]. We present how 25 vertical-cavity surface-emitting lasers (VCSELs), configured in a square array [9], can be coupled and locked to an external drive laser via an optical diffraction scheme in an external cavity. Such a system might constitute the basis for a laser network based implementation of reservoir computing. In our scheme, the external cavity includes a diffractive optical element that allows for scalable coupling [10] between next and second-to-next neighboring VCSELs, and to simultaneously injection lock the VCSELs to an external injection laser. Crucially, every VCSEL in the custom-manufactured arrays can be electrically pumped independently [9], which allows to essentially remove inhomogeneous broadening of the array's lasing wavelengths. In our experiments, we analyze the emission spectra and the dynamical behavior of the VCSELs for different scenarios of feedback, coupling and injection. We observe locking between VCSELs and achieve simultaneous locking of nearly all 25 VCSELs to the external injection laser. We discuss our experimental findings and put them into context for reservoir computing applications

Ex vivo recordings reveal desert locust forelimb control is asymmetric

Lateralized behaviours are widespread among the animals, including insects with their miniature brains, perhaps being a way of maximising neural capacity (reviewed in [1,2]). However, evidence for functional asymmetries in the neural circuitry itself is scarce. Here, using bilateral simultaneous recordings from the ex vivo nervous system of desert locusts, we show that the neural control of their forelimbs is asymmetric. This asymmetry was retained throughout the experimental period and either with or without the suboesophageal ganglion (SOG). These findings provide evidence for hard-wired neural sidedness and contribute to our understanding of the lateralization observed in in-vivo motor behaviours. Knebel et al. show that, in the desert locus motor output to the forelimbs is asymmetric in ex-vivo preparations of the ventral nerve cord. Such hard-wired asymmetry could underlie behavioural asymmetries in this species

Injection locking and coupling the emitters of large VCSEL arrays via diffraction in an external cavity

International audienceNetworks of semiconductor lasers are the foundation of numerous applications and fundamental investigations in nonlinear dynamics, material processing, lighting, and information processing. However, making the usually narrowband semiconductor lasers within the network interact requires both high spectral homogeneity and a fitting coupling concept. Here, we report how we use diffractive optics in an external cavity to experimentally couple vertical-cavity surface-emitting lasers (VCSELs) in a 5×5 array. Out of the 25 lasers, we succeed to spectrally align 22, all of which we lock simultaneously to an external drive laser.Furthermore, we show the considerable coupling interactions between the lasers of the array. This way, we present the largest network of optically coupled semiconductor lasers reported so far and the first detailed characterization of such a diffractively coupled system. Due to the high homogeneity of the lasers, the strong interaction between them, and the scalability of the coupling approach, our VCSEL network is a promising platform for experimental investigations of complex systems, and it has directapplications as a photonic neural network