Experimental Validation of L1 Adaptive Control: Rohrs' Counterexample in Flight

The paper presents new results on the verification and in-flight validation of an L1 adaptive flight control system, and proposes a general methodology for verification and validation of adaptive flight control algorithms. The proposed framework is based on Rohrs counterexample, a benchmark problem presented in the early 80s to show the limitations of adaptive controllers developed at that time. In this paper, the framework is used to evaluate the performance and robustness characteristics of an L1 adaptive control augmentation loop implemented onboard a small unmanned aerial vehicle. Hardware-in-the-loop simulations and flight test results confirm the ability of the L1 adaptive controller to maintain stability and predictable performance of the closed loop adaptive system in the presence of general (artificially injected) unmodeled dynamics. The results demonstrate the advantages of L1 adaptive control as a verifiable robust adaptive control architecture with the potential of reducing flight control design costs and facilitating the transition of adaptive control into advanced flight control systems

Flight Validation of a Metrics Driven L(sub 1) Adaptive Control

The paper addresses initial steps involved in the development and flight implementation of new metrics driven L1 adaptive flight control system. The work concentrates on (i) definition of appropriate control driven metrics that account for the control surface failures; (ii) tailoring recently developed L1 adaptive controller to the design of adaptive flight control systems that explicitly address these metrics in the presence of control surface failures and dynamic changes under adverse flight conditions; (iii) development of a flight control system for implementation of the resulting algorithms onboard of small UAV; and (iv) conducting a comprehensive flight test program that demonstrates performance of the developed adaptive control algorithms in the presence of failures. As the initial milestone the paper concentrates on the adaptive flight system setup and initial efforts addressing the ability of a commercial off-the-shelf AP with and without adaptive augmentation to recover from control surface failures

Polymorphisms of the endothelial nitric oxide synthase (NOS3) gene in preeclampsia: a candidate-gene association study

<p>Abstract</p> <p>Background</p> <p>The endothelial nitric oxide synthase gene (<it>NOS3</it>) has been proposed as a candidate gene for preeclampsia. However, studies so far have produced conflicting results. This study examines the specific role of variants and haplotypes of the <it>NOS3 </it>gene in a population of Caucasian origin.</p> <p>Methods</p> <p>We examined the association of three common variants of the <it>NOS3 </it>gene (4b/a, T-786C and G894T) and their haplotypes in a case-control sample of 102 patients with preeclampsia and 176 women with a history of uncomplicated pregnancies. Genotyping for the <it>NOS3 </it>variants was performed and odds ratios and 95% confidence intervals were obtained to evaluate the association between <it>NOS3 </it>polymorphisms and preeclampsia.</p> <p>Results</p> <p>The single locus analysis for the three variants using various genetic models and a model-free approach revealed no significant association in relation to clinical status. The analysis of haplotypes also showed lack of significant association.</p> <p>Conclusions</p> <p>Given the limitations of the candidate-gene approach in investigating complex traits, the evidence of our study does not support the major contributory role of these common <it>NOS3 </it>variants in preeclampsia. Future larger studies may help in elucidating the genetics of preeclampsia further.</p

Digital Transformation and Strategy in the Banking Sector: Evaluating the Acceptance Rate of E-Services

Digital transformation in the banking sector is a continuous process that affects both the external and internal environment by redesigning internal processes and existing methods. There are many reasons that digital transformation takes place, such as servicing remote areas without physical branches, differentiation from competitors or reduction of operating costs. In any case, there are a lot of doubts about the acceptance of digital technologies. Thus, this article examines the acceptance rate of digital transformation in the banking sector in Greece. One hundred and sixty-one employees at Greek banks completed the survey. A Multivariate Regression Analysis was implemented to analyze the items of the Technology Acceptance Model. The findings of this paper indicate the perception of bank employees with regard to new technologies. This paper provides a practical contribution for executives of Greek banking organizations to schedule targeted educational programs to facilitate the transition to the new digital era for their employees. Executives are curious if employees are ready to accept and implement digitalization in their daily job routine. Therefore, the Technology Acceptance Model can provide answers to executives in facing these challenges

Lack of Association Between Common Endothelial Nitric Oxide Synthase Gene Haplotypes and Left Ventricular Hypertrophy in Hypertension

The endothelial nitric oxide synthase (NOS3) gene has been implicated in the pathogenesis of hypertension-related left ventricular hypertrophy (LVH). Candidate-gene studies have examined the role of NOS3 variation, but reported results are inconsistent. In this study, we investigated the association of three clinically relevant polymorphisms (promoter T786C, intronic 4a/b, and nonsynonymous G894T) in a case–control sample of 230 ethnically homogeneous (Caucasians) patients with essential hypertension, with (n = 64) and without (n = 166) clinically diagnosed LVH. Haplotype analysis was also performed. In single-marker analyses, no significant associations with LVH were detected by univariate and multivariate regression models. In the haplotype-based association analysis, no common haplotype was associated with the development of LVH. A rare haplotype consisting of the three mutant alleles (C-a-T*) was found to be present only in patients with LVH (3.4%) and not in control hypertensive patients. Despite the biological rationale for the involvement of the NOS3 gene in LVH, no evidence for a major role of common NOS3 haplotypic variation was found. Considering the totality of available evidence, single-gene analyses of the NOS3 gene have not uncovered detectable genetic effects, and pathway-based analyses that examine interactions of multiple loci may be more informative about the complex genetic etiology of LVH

Experimental Validation of L1 Adaptive Control: The Rohrs Counterexample in Flight

This paper presents flight-test results that examine the performance and robustness properties of an L1 control augmentation loop implemented onboard a small unmanned aerial vehicle. The framework used for in-flight control evaluation is based on the Rohrs counterexample, a benchmark problem presented in the early 1980s, to show the limitations of adaptive controllers developed at that time. Hardware-in-the-loop simulations and flight-test results confirmthe ability of theL1 flight control system to maintain stability and predictable performance of the closed-loop adaptive system in the presence of general (artificially injected) unmodeled dynamics. The results demonstrate the advantages of L1 control as a robust adaptive control architecture with the potential of facilitating the transition of adaptive control into advanced flight control systems.This work was sponsored in part byNASAgrants NNX08AB97A, NNX08AC81A, and NNL08AA12I

Fibre and Seed Productivity of Industrial Hemp (Cannabis sativa L.) Varieties under Mediterranean Conditions

Farmers&rsquo; interest in renewable raw materials such as hemp (Cannabis sativa L.) fibres has recently increased, but hemp productivity is strongly affected by genotype and environment conditions. A 3-year field experiment was conducted under Mediterranean environment in northern Greece to evaluate the productivity (regarding fibres and seeds) of six monoecious hemp varieties. The vars. Futura 75 and Bialobrzeskie provided the greatest (p &lt; 0.01) fibre productivity (4.57 and 4.27 t ha&minus;1, respectively), which were 77.1% and 65.5%, respectively, greater than that of the least productive var. Fedora 17. However, the vars. Santhica 27, Tygra and Bialobrzeskie provided the highest (p &lt; 0.05) seed yield (2.7, 2.9 and 2.6 t ha&minus;1, respectively), which were 28.6%, 38.1% and 23.8%, respectively, greater than that of the least productive var. Futura 75. Hemp fibre yield was strongly positively correlated with total biomass (R2 = 0.8612) and stem biomass yield (R2 = 0.9742), while it was inversely correlated with fibre strength (R2 = 0.424). Hemp seed yield was not correlated with the hemp plant density, height, total biomass or stem biomass yield. The six hemp genotypes evaluated in the study had &Delta;9-tetrahydrocannabinol (THC) content lower than 0.2% satisfying the European legislation requirements for industrial hemp varieties. The results of the study indicated that, under Mediterranean conditions (northern Greece), the var. Bialobrzeskie showed high productivity, as averaged across years, for both fibres and seeds. This result is very helpful for farmers which should prefer hemp varieties of dual-purpose production (stems and inflorescences or stems and seeds) adapted best to their local environment