15 research outputs found
A Map-Reduce Parallel Approach to Automatic Synthesis of Control Software
Many Control Systems are indeed Software Based Control Systems, i.e. control
systems whose controller consists of control software running on a
microcontroller device. This motivates investigation on Formal Model Based
Design approaches for automatic synthesis of control software.
Available algorithms and tools (e.g., QKS) may require weeks or even months
of computation to synthesize control software for large-size systems. This
motivates search for parallel algorithms for control software synthesis.
In this paper, we present a Map-Reduce style parallel algorithm for control
software synthesis when the controlled system (plant) is modeled as discrete
time linear hybrid system. Furthermore we present an MPI-based implementation
PQKS of our algorithm. To the best of our knowledge, this is the first parallel
approach for control software synthesis.
We experimentally show effectiveness of PQKS on two classical control
synthesis problems: the inverted pendulum and the multi-input buck DC/DC
converter. Experiments show that PQKS efficiency is above 65%. As an example,
PQKS requires about 16 hours to complete the synthesis of control software for
the pendulum on a cluster with 60 processors, instead of the 25 days needed by
the sequential algorithm in QKS.Comment: To be submitted to TACAS 2013. arXiv admin note: substantial text
overlap with arXiv:1207.4474, arXiv:1207.409
Sustained release of VEGF through PLGA microparticles improves vasculogenesis and tissue remodeling in an acute myocardial ischemiaâreperfusion model
The use of pro-angiogenic growth factors in ischemia models has been associated with limited success in the
clinical setting, in part owing to the short lived effect of the injected cytokine. The use of a microparticle
system could allow localized and sustained cytokine release and consequently a prolonged biological effect
with induction of tissue revascularization. To assess the potential of VEGF165 administered as continuous
release in ischemic disease, we compared the effect of delivery of poly(lacticâco-glycolic acid) (PLGA)
microparticles (MP) loaded with VEGF165 with free-VEGF or control empty microparticles in a rat model of
ischemiaâreperfusion. VEGF165 loaded microparticles could be detected in the myocardium of the infarcted
animals for more than a month after transplant and provided sustained delivery of active protein in vitro and
in vivo. One month after treatment, an increase in angiogenesis (small caliber caveolin-1 positive vessels)
and arteriogenesis (α-SMA-positive vessels) was observed in animals treated with VEGF microparticles
(pb0.05), but not in the empty microparticles or free-VEGF groups. Correlating with this data, a positive
remodeling of the heart was also detected in the VEGF-microparticle group with a significantly greater LV
wall thickness (pb0.01). In conclusion, PLGA microparticle is a feasible and promising cytokine delivery
system for treatment of myocardial ischemia. This strategy could be scaled up and explored in pre-clinical
and clinical studies
18F-FDG metabolism in a rat model of chronic infarction: a 17-sector semiquantitative analysis
Strategies to establish the functional benefit of cell therapy in cardiac regeneration and the potential mechanism are needed. Aims: Development of a semi-quantitative method for non invasive assessment of cardiac viability and function in a rat model of myocardial infarction (MI) based on the use of microPET. Animals, methods: Ten rats were subjected to myocardial imaging 2, 7, 14, 30, 60 and 90 days after left coronary artery ligation. Intravenous 18F-fluoro-2-deoxy-2-D-glucose (18F-FDG) was administered and regional 18F activity concentrations per unit area were measured in 17 regions of interest (ROIs) drawn on cardiac polar maps. By comparing the differences in 18F uptake between baseline and each of the follow up time points, parametric polar maps of statistical significance (PPMSS) were calculated. Left ventricular ejection fraction (LVEF) was blindly assessed echocardiographically. All animals were sacrificed for histopathological analysis after 90 days. Results: The diagnostic quality of 18F-FDG microPET images was excellent. PPMSS demonstrated a statistically significant decrease in 18F concentrations as early as 48 hours after MI in 4 of the 17 ROIs (segments 7, 13, 16 and 17; p <0.05) that persisted throughout the study. Semi-quantitative analysis of 18F-FDG uptake correlated with echocardiographic decrease in LVEF (p <0.001). Conclusion: The use of PPMSS based on 18F-FDG-microPET provides valuable semi-quantitative information of heart glucose metabolism allowing for non-invasive follow up thus representing a useful strategy for assessment of novel therapies in cardiac regeneration
Lattice Reduction in Cryptology: An Update
Lattices are regular arrangements of points in space, whose study appeared in the 19th century in both number theory and crystallography