3,076 research outputs found
Modelling and simulation of advanced non-linear autopilot designs
This paper presents the simulation in ESL of a non-linear 6 degree-of-freedom missile model with an advanced, non-linear, multivariable autopilot designed using Rate Actuated Inverse Dynamics (RAID) methods. High performance control of non-linear systems requires the design of advanced, non-linear control systems, such as those used in autopilot design. Traditional linear control system design and analysis techniques are not sufficient for non-linear systems and current non-linear analysis methods are extremely limited. Therefore, the only method available to fully assess the performance of non-linear controller designs is simulation of the non-linear system. For this reason it is an essential part of the analysis and design process of these types of controllers. Non-linear dynamics can be continuous or discontinuous, the aerodynamics of a missile are non-linear but since they are continuous they do not represent a simulation challenge. However, there are multiple sets of discontinuous dynamics present in both the missile control surface model and the autopilot which can lead to multiple discontinuities being reached simultaneously, providing a challenging modeling exercise. The paper demonstrates how this kind of behavior can be successfully modeled and simulated within ESL using a simple switching logic
The Great Disruption: How Machine Intelligence Will Transform the Role of Lawyers in the Delivery of Legal Services
Birds of the Indigirka River Delta, Russia: Historical and Biogeographic Comparisons
We documented the breeding status and relative abundance of all avian species on the coastal portion of the Indigirka River Delta during spring and summer 1993-95. Data on avifaunal composition were then compared to data from adjacent areas from Eastern Siberia to the Chukotka Peninsula to evaluate how species composition changes longitudinally within the arctic and typical tundra zones of northern Russia. We recorded 63 species on the Indigirka River Delta, 37 (58.7%) of which were confirmed breeders during at least one of the three years. Five new species were recorded breeding (Arenaria interpres, Calidris acuminata, Limnodromus scolopaceus, Stercorarius parasiticus, and Asio flammeus), and 13 previously unrecorded species were observed during this study. We also identified several species of rare or threatened status in Russia and North America, including Branta bernicla, Somateria fischeri, Polysticta stelleri, and Rhodostethia rosea. We used parsimony and distance matrix methods to compare the breeding species richness on the Indigirka River Delta to that of six other Russian Arctic areas. Biogeographic comparisons revealed the presence of two clades in the Russian Arctic: the Lena River Delta east to Chaun Delta and the Chukotka Peninsula.Durant le printemps et l'été de 1993-95, on a documenté le statut de reproducteurs ainsi que l'abondance relative de toutes les espÚces aviaires dans la partie littorale du delta de l'Indigirka. On a ensuite comparé les données sur la composition aviaire à des données provenant de régions contiguës allant de la Sibérie orientale à la péninsule Tchoukotka, en vue d'évaluer la façon dont la composition des espÚces évolue longitudinalement à l'intérieur des zones arctiques et des zones typiques de la toundra de la Russie septentrionale. On a enregistré 63 espÚces dans le delta de l'Indigirka, dont 37 (58,7 p. cent) étaient des reproducteurs durant au moins une des trois années. On a enregistré cinq nouvelles espÚces reproductrices (Arenaria interpres, Calidris acuminata, Limnodromus scolopaceus, Stercocarius parasiticus et Asio flammeus), et, au cours de l'étude, on a observé 13 espÚces qui n'avaient jamais été relevées auparavant. On a aussi identifié plusieurs espÚces classées rares ou menacées en Russie et en Amérique du Nord, y compris Branta bernicla, Somateria fischeri, Polysticta stelleri et Rhodostethia rosea. On a employé les méthodes de parcimonie et de matrices de distance pour comparer la diversité des espÚces reproductrices présentes dans le delta de l'Indigirka avec six autres régions arctiques de Russie. Les comparaisons biogéographiques ont révélé la présence de deux clades dans l'Arctique russe: le delta de la Lena à l'est jusqu'au delta du fleuve Chaun, et la péninsule Tchoukotka
httk: R Package for High-Throughput Toxicokinetics
Thousands of chemicals have been profiled by high-throughput screening programs such as ToxCast and Tox21; these chemicals are tested in part because most of them have limited or no data on hazard, exposure, or toxicokinetics. Toxicokinetic models aid in predicting tissue concentrations resulting from chemical exposure, and a "reverse dosimetry" approach can be used to predict exposure doses sufficient to cause tissue concentrations that have been identified as bioactive by high-throughput screening. We have created four toxicokinetic models within the R software package httk. These models are designed to be parameterized using high-throughput in vitro data (plasma protein binding and hepatic clearance), as well as structure-derived physicochemical properties and species-specific physiological data. The package contains tools for Monte Carlo sampling and reverse dosimetry along with functions for the analysis of concentration vs. time simulations. The package can currently use human in vitro data to make predictions for 553 chemicals in humans, rats, mice, dogs, and rabbits, including 94 pharmaceuticals and 415 ToxCast chemicals. For 67 of these chemicals, the package includes rat-specific in vitro data. This package is structured to be augmented with additional chemical data as they become available. Package httk enables the inclusion of toxicokinetics in the statistical analysis of chemicals undergoing high-throughput screening
A Merger Scenario for the Dynamics of Abell 665
We present new redshift measurements for 55 galaxies in the vicinity of the
rich galaxy cluster Abell 665. When combined with results from the literature,
we have good velocity measurements for a sample of 77 confirmed cluster members
from which we derive the cluster's redshift z=0.1829 +/- 0.0005 and
line-of-sight velocity dispersion of 1390 +/- 120 km/s. Our analysis of the
kinematical and spatial data for the subset of galaxies located within the
central 750 kpc reveals only subtle evidence for substructure and
non-Gaussianity in the velocity distribution. We find that the brightest
cluster member is not moving significantly relative to the other galaxies near
the center of the cluster. On the other hand, our deep ROSAT high resolution
image of A665 shows strong evidence for isophotal twisting and centroid
variation, thereby confirming previous suggestions of significant substructure
in the hot X-ray--emitting intracluster gas. In light of this evident
substructure, we have compared the optical velocity data with N-body
simulations of head-on cluster mergers. We find that a merger of two similar
mass subclusters (mass ratios of 1:1 or 1:2) seen close to the time of
core-crossing produces velocity distributions that are consistent with that
observed.Comment: 30 pages and 7 figures. Accepted by the Astrophysical Journal Full
resoultion figures 1 and 3 available in postscript at
http://www.physics.rutgers.edu/~percy/A665paper.htm
Subversive Legal Education:Reformist Steps TowardAbolitionist Visions
Exclusivity in legal education divides traditional scholars, students, and impacted communities most disproportionately harmed by the legal education system. While traditional legal scholars tend to embrace traditional legal education, organic juristsâthose who are historically excluded from legal education and those who educate themselves and their communities about their legal rights and realitiesâoften reject the inaccessibility of legal education and its power. This Essay joins a team of community legal writers to imagine a set of principles for subversive legal education. Together, weâformerly incarcerated pro se litigants, paralegals for intergenerational movement lawyering initiatives, first-generation law students and lawyers, persons with years of formal legal expertise, and people who have gained expertise outside of law schoolsâbring together critical insight about the impact of legal educationâs exclusivity and the means by which we have worked to expand access necessary for our survival. The Essay explores the frameworks of movement law, Black feminism, and abolition as impacted people look to reclaim experiences and create tools for subversive legal education that teaches that the law belongs to the people and how they themselves can make and change the law. In Part I, we explore reformist strategies that address the pervasive racism in legal education and the bar admission system while leaving the institutional framework intact. In Part II, we share four case studies of transformative legal tools; these tools work to subvert legal education from a machine that excludes, extracts, and exploits our communities into a mechanism that educates and liberates our communities. In Part III, these case studies illuminate principles that prioritizes access, transparency, and collective design with impacted scholars and communities. This is a first step toward abolitionâa radical reimagination of legal education that makes legal knowledge a right, that democratizes legal power, and that recognizes that the production of legal knowledge, teaching, and scholarship must include those whom the law impacts, consistent with the disability rights activism mantra âNothing About Us Without Us.â For us, abolishing the existing structures perpetuating exclusive enclaves in legal education can assist in other abolitionist struggles, such as abolition of the prison industrial complex; these struggles are tied, not siloed from one another
Promising Functional Readouts of Immunity in a Blood-Stage Malaria Vaccine Trial
The authors discuss results from an early trial of a vaccine based on Plasmodium MSP-3 protein reported by Pierre Druilhe and colleagues
Investigating Perceptual Congruence Between Data and Display Dimensions in Sonification
The relationships between sounds and their perceived meaning and connotations are complex, making auditory perception an important factor to consider when designing sonification systems. Listeners often have a mental model of how a data variable should sound during sonification and this model is not considered in most data:sound mappings. This can lead to mappings that are difficult to use and can cause confusion. To investigate this issue, we conducted a magnitude estimation experiment to map how roughness, noise and pitch relate to the perceived magnitude of stress, error and danger. These parameters were chosen due to previous findings which suggest perceptual congruency between these auditory sensations and conceptual variables. Results from this experiment show that polarity and scaling preference are dependent on the data:sound mapping. This work provides polarity and scaling values that may be directly utilised by sonification designers to improve auditory displays in areas such as accessible and mobile computing, process-monitoring and biofeedback
Introducing willingness-to-pay for noise changes into transport appraisal: an application of benefit transfer.
Numerous research studies have elicited willingness-to-pay values for transport-related noise, however, in many industrialised countries including the UK, noise costs and benefits are still not incorporated into appraisals for most transport projects and policy changes (Odgaard et al, 2005; Grant-Muller et al, 2001). This paper describes the actions recently taken in the UK to address this issue, comprising: primary research based on the city of Birmingham; an international review of willingness-to-pay evidence; development of values using benefit transfers over time and locations; and integration with appraisal methods. Amongst the main findings are: that the willingness-to-pay estimates derived for the UK are broadly comparable with those used in appraisal elsewhere in Europe; that there is a case for a lower threshold at
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45dB(A)Leq,18hr1 rather than the more conventional 55dB(A); and that values per dB(A) increase with the noise level above this threshold. There are significant issues over the valuation of rail versus road noise, the neglect of non-residential noise and the valuation of high noise levels in different countries. Conclusions are drawn regarding the feasibility of noise valuation based on benefit transfers in the UK and elsewhere, and future research needs in this field are discussed
Identification of candidate odorant degrading gene/enzyme systems in the antennal transcriptome of Drosophila melanogaster
AbstractThe metabolism of volatile signal molecules by odorant degrading enzymes (ODEs) is crucial to the ongoing sensitivity and specificity of chemoreception in various insects, and a few specific esterases, cytochrome P450s, glutathione S-transferases (GSTs) and UDP-glycosyltransferases (UGTs) have previously been implicated in this process. Significant progress has been made in characterizing ODEs in Lepidoptera but very little is known about them in Diptera, including in Drosophila melanogaster, a major insect model. We have therefore carried out a transcriptomic analysis of the antennae of D. melanogaster in order to identify candidate ODEs. Virgin male and female and mated female antennal transcriptomes were determined by RNAseq. As with the Lepidoptera, we found that many esterases, cytochrome P450 enzymes, GSTs and UGTs are expressed in D. melanogaster antennae. As olfactory genes generally show selective expression in the antennae, a comparison to previously published transcriptomes for other tissues has been performed, showing preferential expression in the antennae for one esterase, JHEdup, one cytochrome P450, CYP308a1, and one GST, GSTE4. These largely uncharacterized enzymes are now prime candidates for ODE functions. JHEdup was expressed heterologously and found to have high catalytic activity against a chemically diverse group of known ester odorants for this species. This is a finding consistent with an ODE although it might suggest a general role in clearing several odorants rather than a specific role in clearing a particular odorant. Our findings do not preclude the possibility of odorant degrading functions for other antennally expressed esterases, P450s, GSTs and UGTs but, if so, they suggest that these enzymes also have additional functions in other tissues
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