3,281 research outputs found

    Wing Design Using SAIL

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    In engineering spaces where modeling is difficult, engineers seek a variety of well performing solutions in order to concentrate resources on promising areas of the problem space. We call this process illumination. Gaire et al have designed an algorithm specifically for illumination of problem spaces where the underlying model is computationally expensive. This algorithm, Surrogate Assisted Illumination (SAIL) uses an evolutionary algorithm called MAP-Elites to do illumination. However, SAIL introduces a Gaussian process to simulate the computationally expensive model, and Bayesian optimization for quality control of the Gaussian process. SAIL has demonstrated potential for finding a variety of well performing solutions when applied to the design of aerodynamic hulls for velomobiles. We will walk through each of the components of the SAIL algorithm, and the results of the velomobile experiment

    Revision of the Atmospheric Delay Correction for ICESat-2 Laser Altimeter Ranges

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    In 2001 Herring and Quinn proposed the algorithm for correction for atmospheric delay to ICESat-1 GLAS laser altimeter. The purpose of this document is to provide a revision of the algorithm suitable for processing the data from ICESat-2 mission scheduled for launch in 2016. The goal of the revision is to provide a procedure for atmospheric delay correction that would be precise to 1 mm level. The actual accuracy of delay computation will be somewhat less, but it will be limited only by imperfection of the used numerical weather model

    Simple Stateless Steganography

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    We put forward the first secret-key steganographic construction that is both black-box (i.e., the sender need not have knowledge of the channel beyond the ability to sample from it) and stateless (i.e., the sender and the recipient need not maintain synchronized state when sending multiple bits). Both of these properties are important: the first because in many settings it is unrealistic to assume detailed knowledge of the underlying channel distribution, and the second because maintaining synchronized state between the sender and the recipient is particularly problematic in steganography, where communication to resynchronize will alert the adversary. For channels of sufficient entropy, our construction is more efficient than previous black-box constructions. Moreover, it is the first one to provide a tradeoff between the number of samples the encoder needs and the rate at which hiddentext is transmitted

    Verrucous carcinoma of the vulva: patterns of care and treatment outcomes.

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    Background: Verrucous vulvar carcinoma (VC) is an uncommon and distinct histologic subtype of squamous cell carcinoma (SCC). The available literature on VC is currently limited to case reports and small single institution studies. Aims: The goals of this study were to analyze data from the National Cancer Database (NCDB) to quantitate the incidence of VC and to investigate the effects of patient demographics, tumor characteristics, and treatment regimens on overall survival (OS) in women with verrucous vulvar carcinoma. Methods and results: Patients diagnosed with vulvar SCC or VC between the years of 2004 and 2016 were identified in the NCDB. OS was assessed with Kaplan–Meier curves and the log-rank test. Construction of a Cox model compared survival after controlling for confounding variables. The reported incidence of SCC of the vulva has significantly increased since 2004 (p \u3c .0001). In contrast, the incidence of VC has remained stable (p = .344) since 2004. Compared to SCC, VC was significantly more likely to be diagnosed in older women (p \u3c .0001) and treated with surgery alone (p \u3c .0001). However, on propensity score weighted analysis there was a trend toward improved 5-year OS in women with VC compared to those with SCC (63.4% vs. 57.7%, p = .0794). Multivariable Cox survival analysis showed an improvement in OS in VC patients treated with both primary site and regional lymph node surgery compared to primary site surgery alone (adjusted hazard ratio [aHR] 0.67, 95% confidence interval [CI] 0.46–0.97, p = .0357). Conclusion: Verrucous carcinoma is more likely to present in older women. Regional lymph node surgery in addition to primary site surgery significantly improves OS in VC patients
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