Abstract Interpretation with Unfoldings

We present and evaluate a technique for computing path-sensitive interference conditions during abstract interpretation of concurrent programs. In lieu of fixed point computation, we use prime event structures to compactly represent causal dependence and interference between sequences of transformers. Our main contribution is an unfolding algorithm that uses a new notion of independence to avoid redundant transformer application, thread-local fixed points to reduce the size of the unfolding, and a novel cutoff criterion based on subsumption to guarantee termination of the analysis. Our experiments show that the abstract unfolding produces an order of magnitude fewer false alarms than a mature abstract interpreter, while being several orders of magnitude faster than solver-based tools that have the same precision.Comment: Extended version of the paper (with the same title and authors) to appear at CAV 201

Strain, size and composition of InAs Quantum Sticks, embedded in InP, by means of Grazing Incidence X-ray Anomalous Diffraction

We have used x-ray anomalous diffraction to extract the x-ray structure factor of InAs quantum stick-like islands, embedded in InP. The average height of the quantum sticks (QSs), as deduced from the width of the structure factor profile is 2.54nm. The InAs out of plane deformation, relative to InP, is equal to 6.1%. Diffraction Anomalous Fine Structure provides a clear evidence of pure InAs QSs. Finite Difference Method calculations reproduce well the diffraction data, and give the strain along the growth direction. Chemical mixing at interfaces is at most of 1MLComment: 9 pages, 7 figures, submitte

Slow-light enhanced light-matter interactions with applications to gas sensing

Optical gas detection in microsystems is limited by the short micron scale optical path length available. Recently, the concept of slow-light enhanced absorption has been proposed as a route to compensate for the short path length in miniaturized absorption cells. We extend the previous perturbation theory to the case of a Bragg stack infiltrated by a spectrally strongly dispersive gas with a narrow and distinct absorption peak. We show that considerable signal enhancement is possible. As an example, we consider a Bragg stack consisting of PMMA infiltrated by O2. Here, the required optical path length for visible to near-infrared detection (~760 nm) can be reduced by at least a factor of 10^2, making a path length of 1 mm feasible. By using this technique, optical gas detection can potentially be made possible in microsystems

Enhanced spontaneous emission rate from single InAs quantum dots in a photonic crystal nanocavity at telecom wavelengths

The authors demonstrate coupling at 1.3 micro m between single InAs quantum dots (QDs) and a mode of a two dimensional photonic crystal (PhC) defect cavity with a quality factor of 15 000. By spectrally tuning the cavity mode, they induce coupling with excitonic lines. They perform a time integrated and time-resolved photoluminescence and measure an eightfold increase in the spontaneous emission rate inducing a coupling efficiency of 96%. These measurements indicate the potential of single QDs in PhC cavities as efficient single-photon emitters for fiber-based quantum information processing applications. [on SciFinder (R)

Field test of quantum key distribution in the Tokyo QKD Network

A novel secure communication network with quantum key distribution in a metropolitan area is reported. Different QKD schemes are integrated to demonstrate secure TV conferencing over a distance of 45km, stable long-term operation, and application to secure mobile phones.Comment: 21 pages, 19 figure

Dynamics on Multiple Potential Energy Surfaces: Quantitative Studies of Elementary Processes Relevant to Hypersonics

The determination of thermal and vibrational relaxation rates of triatomic systems suitable for application in hypersonic model calculations is discussed. For this, potential energy surfaces for ground and electronically excited state species need to be computed and represented with high accuracy and quasiclassical or quantum nuclear dynamics simulations provide the basis for determining the relevant rates. These include thermal reaction rates, state-to-state cross-sections, or vibrational relaxation rates. For exemplary systems - [NNO], [NOO], and [CNO] - all individual steps are described and a literature overview for them is provided. Finally, as some of these quantities involve considerable computational expense, for the example of state-to-state cross sections the construction of an efficient model based on neural networks is discussed. All such data is required and being used in more coarse-grained computational fluid dynamics simulations.Comment: Review article, 46 pages, 8 figure

Integrated liquid-core optical fibers --- ultra-efficient nonlinear liquid photonics

We have developed a novel integrated platform for liquid photonics based on liquid core optical fiber (LCOF). The platform is created by fusion splicing liquid core optical fiber to standard single-mode optical fiber making it fully integrated and practical - a major challenge that has greatly hindered progress in liquid-photonic applications. As an example, we report here the realization of ultralow threshold Raman generation using an integrated CS2 filled LCOF pumped with sub-nanosecond pulses at 1064nm and 532nm. The measured energy threshold for the Stokes generation is ~ 1nJ, about three orders of magnitude lower than previously reported values in the literature for hydrogen gas. The integrated LCOF platform opens up new possibilities for ultralow power nonlinear optics such as efficient white light generation for displays, mid-IR generation, slow light generation, parametric amplification, all-optical switching and wavelength conversion using liquids that have orders of magnitude larger optical nonlinearities compared with silica glass.Comment: 4 pages, 3 figure

The relationship between social support and health-related quality of life in patients with antiphospholipid (hughes) syndrome

Objective: Antiphospholipid (Hughes) syndrome (APS) is recognised as a systemic autoimmune disease defined by recurrent thromboembolic events and/or pregnancy morbidity. Little is known about the psychological burden of this long-term condition. This study aims to explore the relationship between social support and health-related quality of life (HRQoL) in patients with APS. Methods: A total of 270 patients with a clinical diagnosis of APS participated in a cross-sectional online questionnaire survey. Data included demographics, disease-related information, social support and HRQoL. Results: Both perceived and ideal social support were associated with HRQoL in APS. Patients reported receiving insufficient social support. Perceived emotional support was related to physical functioning (B = 7.77, p = .006, 95% CI: 2.25, 13.29); perceived instrumental support was associated with bodily pain (B = 17.52, p <  .001, 95% CI: 11.15, 23.90) and perceived informational support with physical and social functioning (B = −6.30, p = .05, 95% CI: −12.52, −0.08; B = 8.06, p = .02, 95% CI: 1.17, 14.94). Ideal emotional support was related to physical and social functioning (B = 5.80, p = .04, 95% CI: 0.26, 11.34; B = 7.53, p = .04, 95% CI: 0.55, 14.51); ideal instrumental support was associated with mental health (B = 4.73, p = .03, 95% CI: 0.38, 9.07) and ideal informational support with vitality (B = 5.85, p = .01, 95% CI: 1.23, 10.46). Conclusion: Social support was linked to HRQoL in patients with APS. Insufficient social support was associated with limitations in various HRQoL domains. Increasing social support especially through provision of disease-specific education might contribute to improving HRQoL in patients with APS. Patient-tailored interventions addressing psychosocial aspects of living with APS are needed to improve patients’ psychological and physical status