Saying Hello World with Henshin - A Solution to the TTC 2011 Instructive Case

This paper gives an overview of the Henshin solution to the Hello World case study of the Transformation Tool Contest 2011, intended to show basic language concepts and constructs.Comment: In Proceedings TTC 2011, arXiv:1111.440

Liveness-Driven Random Program Generation

Randomly generated programs are popular for testing compilers and program analysis tools, with hundreds of bugs in real-world C compilers found by random testing. However, existing random program generators may generate large amounts of dead code (computations whose result is never used). This leaves relatively little code to exercise a target compiler's more complex optimizations. To address this shortcoming, we introduce liveness-driven random program generation. In this approach the random program is constructed bottom-up, guided by a simultaneous structural data-flow analysis to ensure that the generator never generates dead code. The algorithm is implemented as a plugin for the Frama-C framework. We evaluate it in comparison to Csmith, the standard random C program generator. Our tool generates programs that compile to more machine code with a more complex instruction mix.Comment: Pre-proceedings paper presented at the 27th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2017), Namur, Belgium, 10-12 October 2017 (arXiv:1708.07854

Solving the TTC 2011 Reengineering Case with Henshin

This paper presents the Henshin solution to the Model Transformations for Program Understanding case study as part of the Transformation Tool Contest 2011.Comment: In Proceedings TTC 2011, arXiv:1111.440

Particle hydrodynamics with tessellation techniques

Lagrangian smoothed particle hydrodynamics (SPH) is a well-established approach to model fluids in astrophysical problems, thanks to its geometric flexibility and ability to automatically adjust the spatial resolution to the clumping of matter. However, a number of recent studies have emphasized inaccuracies of SPH in the treatment of fluid instabilities. The origin of these numerical problems can be traced back to spurious surface effects across contact discontinuities, and to SPH's inherent prevention of mixing at the particle level. We here investigate a new fluid particle model where the density estimate is carried out with the help of an auxiliary mesh constructed as the Voronoi tessellation of the simulation particles instead of an adaptive smoothing kernel. This Voronoi-based approach improves the ability of the scheme to represent sharp contact discontinuities. We show that this eliminates spurious surface tension effects present in SPH and that play a role in suppressing certain fluid instabilities. We find that the new `Voronoi Particle Hydrodynamics' described here produces comparable results than SPH in shocks, and better ones in turbulent regimes of pure hydrodynamical simulations. We also discuss formulations of the artificial viscosity needed in this scheme and how judiciously chosen correction forces can be derived in order to maintain a high degree of particle order and hence a regular Voronoi mesh. This is especially helpful in simulating self-gravitating fluids with existing gravity solvers used for N-body simulations.Comment: 26 pages, 24 figures, currentversion is accepted by MNRA

Testing the differential adhesion hypothesis across the epithelial− mesenchymal transition

Weanalyze the mechanical properties of three epithelial/mesenchymal cell lines (MCF-10A, MDAMB- 231, MDA-MB-436) that exhibit a shift in E-, N- and P-cadherin levels characteristic of an epithelial−mesenchymal transition associated with processes such as metastasis, to quantify the role of cell cohesion in cell sorting and compartmentalization. Wedevelop a unique set of methods to measure cell–cell adhesiveness, cell stiffness and cell shapes, and compare the results to predictions from cell sorting in mixtures of cell populations.Wefind that the final sorted state is extremely robust among all three cell lines independent of epithelial or mesenchymal state, suggesting that cell sorting may play an important role in organization and boundary formation in tumours.Wefind that surface densities of adhesive molecules do not correlate with measured cell–cell adhesion, but do correlate with cell shapes, cell stiffness and the rate at which cells sort, in accordance with an extended version of the differential adhesion hypothesis (DAH). Surprisingly, theDAHdoes not correctly predict the final sorted state. This suggests that these tissues are not behaving as immiscible fluids, and that dynamical effects such as directional motility, friction and jamming may play an important role in tissue compartmentalization across the epithelial−mesenchymal transition

The Physical Conditions of the Intrinsic N V Narrow Absorption Line Systems of Three Quasars

We employ detailed photoionization models to infer the physical conditions of intrinsic narrow absorption line systems found in high resolution spectra of three quasars at z=2.6-3.0. We focus on a family of intrinsic absorbers characterized by N V lines that are strong relative to the Ly-alpha lines. The inferred physical conditions are similar for the three intrinsic N V absorbers, with metallicities greater than 10 times the solar value (assuming a solar abundance pattern), and with high ionization parameters (log U ~ 0). Thus, we conclude that the unusual strength of the N V lines results from a combination of partial coverage, a high ionization state, and high metallicity. We consider whether dilution of the absorption lines by flux from the broad-emission line region can lead us to overestimate the metallicities and we find that this is an unlikely possibility. The high abundances that we infer are not surprising in the context of scenarios in which metal enrichment takes place very early on in massive galaxies. We estimate that the mass outflow rate in the absorbing gas (which is likely to have a filamentary structure) is less than a few solar masses per year under the most optimistic assumptions, although it may be embedded in a much hotter, more massive outflow.Comment: To appear in the Astrophysical Journa

Prospectus, December 17, 1987

https://spark.parkland.edu/prospectus_1987/1029/thumbnail.jp

Consistent validation of Copernicus Sentinel-2 and Sentinel-3 optical missions

The Copernicus program is a European initiative for the implementation of information services dealing with environment and security, mainly based on observation data received from Earth Observation (EO) satellites. In the frame of this program, ESA launched the Copernicus Sentinel-2 and Sentinel-3 optical imaging satellites. These satellites deliver a new generation of optical data products designed to directly feed downstream services mainly related to land and ocean monitoring, emergency management and security. To ensure the highest quality of Earth Observation data from the Copernicus Sentinel-2 and Sentinel-3 optical missions, ESA set up the Optical Mission Performance Centre (OPT-MPC) supported by several Expert Support Laboratories (ESL). The OPT-MPC brings together the experience of the former separated S2 and S3 Mission Performance Centers. The main objective of the working group on atmospheric correction within OPT-MPC is to employ synergies across the missions on surface reflectance (SR), aerosol optical thickness (AOT) and water vapor (WV) validation. Harmonization of validation practices, approaches, metrics, terms and definitions will support inter-operability among missions. This can also result in a guideline for good validation practice for other optical remote sensing missions in the Copernicus program and worldwide. Eventually it will give recommendations for algorithm improvements. This presentation reports first results of this process and will show some examples for consistent validation of Copernicus Sentinel-2 and Sentinel-3 optical missions. It invites for discussion about validation methodologies and standards in the community

Expressions 1978

Expressions contains selected work from some of the Creative Writing Contest winners and honorable mentions along with Commercial Art students at Des Moines Area Community College. Design, topography, and layout was accomplished by Journalism students.https://openspace.dmacc.edu/expressions/1000/thumbnail.jp