Adaptive model reference control of highly maneuverable high performance aircraft

This thesis presents an adaptive model reference controller for a highly maneuverable high performance aircraft, in particular, a modified F18. An adaptive controller is developed to maneuver an aircraft at a high angle of attack. Thus, the aircraft is required to fly over a highly nonlinear flight regime. The adaptive controller presented in this thesis can be viewed as a combination of a linear and a nonlinear controller. Around a fixed flight condition the adaptive controller converges to a linear controller; however, the controller remains a nonlinear controller during maneuvers. The contributions of this thesis lie in two areas. The first area is in control. A successful application of linear adaptive control is presented for a highly nonlinear system. A new method is used to generate the reference trajectory. The reference model uses output feedback to improve the reference trajectory. It is shown that this improvement is necessary because of the control limitations. This work is also important to the control of highly maneuverable high performance aircraft. A successful adaptive controller has been developed to rapidly maneuver an aircraft to a high angle of attack. The main focus of this thesis is adaptive control

Transcript: Session 2: The Problem of State Judicial Campaign “Arms Races”—What Can Be Done in the State Legislatures and State Courts?

Many years ago, when my hair was still thick, this justice spoke at a conference on state court judicial elections. I was not there, but the story goes that when it came to an audience question, an idealistic young man asked this West Virginia supreme court justice: How do you go about becoming a state supreme court justice? Do you have to go to a good law school? Do you have to become involved in the state bar association? Do you have to become involved in civic organizations? Do you have to become a trial judge, then an appellate judge, and then tender your resume to the governor and hope that merit is the measure? Is that how you have to do it? Without pausing for an ethical second, the bold justice from West Virginia said, “Money, my man, money.” This is the realist backdrop or subtext for much of the discussion about Caperton and also White. At least some of the subtext includes an animosity to judicial elections and an attempt to defang them

Transcript: Session 2: The Problem of State Judicial Campaign “Arms Races”—What Can Be Done in the State Legislatures and State Courts?

Many years ago, when my hair was still thick, this justice spoke at a conference on state court judicial elections. I was not there, but the story goes that when it came to an audience question, an idealistic young man asked this West Virginia supreme court justice: How do you go about becoming a state supreme court justice? Do you have to go to a good law school? Do you have to become involved in the state bar association? Do you have to become involved in civic organizations? Do you have to become a trial judge, then an appellate judge, and then tender your resume to the governor and hope that merit is the measure? Is that how you have to do it? Without pausing for an ethical second, the bold justice from West Virginia said, “Money, my man, money.” This is the realist backdrop or subtext for much of the discussion about Caperton and also White. At least some of the subtext includes an animosity to judicial elections and an attempt to defang them

Pegasus V -- a newly discovered ultra-faint dwarf galaxy on the outskirts of Andromeda

We report the discovery of an ultra-faint dwarf in the constellation of Pegasus. Pegasus~V (Peg~V) was initially identified in the public imaging data release of the DESI Legacy Imaging Surveys and confirmed with deep imaging from Gemini/GMOS-N. The colour-magnitude diagram shows a sparse red giant branch (RGB) population and a strong over-density of blue horizontal branch stars. We measure a distance to Peg~V of $D=692^{+33}_{-31}$~kpc, making it a distant satellite of Andromeda with $M_V=-6.3\pm0.2$ and a half-light radius of $r_{\rm half}=89\pm41$~pc. It is located $\sim260$~kpc from Andromeda in the outskirts of its halo. The RGB is well-fit by a metal-poor isochrone with [Fe/H]$=-3.2$, suggesting it is very metal poor. This, combined with its blue horizontal branch could imply that it is a reionisation fossil. This is the first detection of an ultra-faint dwarf outside the deep Pan-Andromeda Archaeological Survey area, and points to a rich, faint satellite population in the outskirts of our nearest neighbour.Comment: Submitted to MNRAS Letters. 6 pages, 4 figures. Comments welcom

Pisces VII: Discovery of a possible satellite of Messier 33 in the DESI Legacy Imaging Surveys

We report deep imaging observations with DOLoRes@TNG of an ultra-faint dwarf satellite candidate of the Triangulum galaxy (M33) found by visual inspection of the public imaging data release of the DESI Legacy Imaging Surveys. Pisces VII/Triangulum (Tri) III is found at a projected distance of 72 kpc from M33, and using the tip of the red giant branch method we estimate a distance of D=1.0 +0.3,-0.2 Mpc, meaning the galaxy could either be an isolated ultra-faint or the second known satellite of M33. We estimate an absolute magnitude of M_V=-6.1+/-0.2 if Pisces VII/Tri II is at the distance of M33, or as bright as M_V=-6.8+/-0.2 if the galaxy is isolated. At the isolated distance, it has a physical half-light radius of r_h=131+/-61 pc consistent with similarly faint galaxies around the Milky Way. As the tip of the red giant branch is sparsely populated, constraining a precision distance is not possible, but if Pisces VII/Tri III can be confirmed as a true satellite of M33 it is a significant finding. With only one potential satellite detected around M33 previously (Andromeda XXII/Tri I), it lacks a significant satellite population in stark contrast to the similarly massive Large Magellanic Cloud. The detection of more satellites in the outskirts of M33 could help to better illuminate if this discrepancy between expectation and observations is due to a poor understanding of the galaxy formation process, or if it is due to the low luminosity and surface brightness of the M33 satellite population which has thus far fallen below the detection limits of previous surveys. If it is truly isolated, it would be the faintest known field dwarf detected to date.Comment: 10 pages, 9 figures, 2 tables, accepted for publication in MNRAS. This final version includes a moderate revision after the referee's comments and a correct titl

Environmental DNA captures elasmobranch diversity in a temperate marine ecosystem

Abstract: Many sharks, skates, and rays (elasmobranchs) are highly threatened by the activities of commercial fisheries, and a clear understanding of their distributions, diversity, and abundance can guide protective measures. However, surveying and monitoring elasmobranch species can be highly invasive or resource‐intensive, and utilization of non‐invasive environmental DNA‐based methods may overcome these problems. Here, we studied spatial and seasonal variation in the elasmobranch community of the Western English Channel using environmental DNA (eDNA) collected from surface and bottom waters periodically over an annual cycle (2017–2018). In total we recovered 13 elasmobranch species within eDNA samples, and the number of transformed eDNA reads was positively associated with species (hourly) catch data resolved from 105‐year time series trawl data (1914–2018). These results demonstrate the ability of eDNA to detect and semi‐quantitatively reflect the prevalence of historically dominant and rare elasmobranch species in this region. Notably, eDNA recorded a greater number of species per sampling event than a conventional trawl survey in the same area over the same sampling years (2017–2018). Several threatened species were recovered within the eDNA, including undulate ray, porbeagle shark, and thresher shark. Using eDNA, we found differences in elasmobranch communities among sampling stations and between seasons, but not between sampling depths. Collectively, our results suggest that non‐invasive eDNA‐based methods can be used to study the spatial and seasonal changes in the diversity and abundance of whole elasmobranch communities within temperate shelf habitats. Given the threatened status of many elasmobranchs in human‐impacted marine environments, eDNA analysis is poised to provide key information on their diversity and distributions to inform conservation‐focused monitoring and management

Structure of Tagatose-1,6-bisphosphate Aldolase. Insight into chiral discrimination, mechanism, and specificity of class II aldolases

Tagatose-1,6-bisphosphate aldolase (TBPA) is a tetrameric class II aldolase that catalyzes the reversible condensation of dihydroxyacetone phosphate with glyceraldehyde 3-phosphate to produce tagatose 1,6-bisphosphate. The high resolution (1.45 Å) crystal structure of the Escherichia coli enzyme, encoded by the agaY gene, complexed with phosphoglycolohydroxamate (PGH) has been determined. Two subunits comprise the asymmetric unit, and a crystallographic 2-fold axis generates the functional tetramer. A complex network of hydrogen bonds position side chains in the active site that is occupied by two cations. An unusual Na(+) binding site is created using a interaction with Tyr(183) in addition to five oxygen ligands. The catalytic Zn(2+) is five-coordinate using three histidine nitrogens and two PGH oxygens. Comparisons of TBPA with the related fructose-1,6-bisphosphate aldolase (FBPA) identifies common features with implications for the mechanism. Because the major product of the condensation catalyzed by the enzymes differs in the chirality at a single position, models of FBPA and TBPA with their cognate bisphosphate products provide insight into chiral discrimination by these aldolases. The TBPA active site is more open on one side than FBPA, and this contributes to a less specific enzyme. The availability of more space and a wider range of aldehyde partners used by TBPA together with the highly specific nature of FBPA suggest that TBPA might be a preferred enzyme to modify for use in biotransformation chemistry

Verifiable self-certifying autonomous systems

Autonomous systems are increasingly being used in safety-and mission-critical domains, including aviation, manufacturing, healthcare and the automotive industry. Systems for such domains are often verified with respect to essential requirements set by a regulator, as part of a process called certification. In principle, autonomous systems can be deployed if they can be certified for use. However, certification is especially challenging as the condition of both the system and its environment will surely change, limiting the effective use of the system. In this paper we discuss the technological and regulatory background for such systems, and introduce an architectural framework that supports verifiably-correct dynamic self-certification by the system, potentially allowing deployed systems to operate more safely and effectively