Miracle-dz/UniFAR-FTUs huggingface dataset:
Generalized classical axially symmetric dual-reflector antennas

This work presents a generalized study of classical axially symmetric dual-reflector antennas. The antenna dishes are simply described by conic sections, arranged to reduce the main-reflector radiation toward the subreflector surface. The dual-reflector configuration provides a uniform-phase field distribution over the illuminated portion of the aperture, starting from a spherical-wave feed source at the antenna primary focus. All possible configurations are characterized into a total of four distinct groups. Simple closed-form design equations and the aperture field distribution are derived, in a unified way, for all these kinds of generalized antennas using the principles of geometrical optics. The formulation is applied in a parametric study to establish the configurations yielding maximum radiation efficiency (not including diffraction effects). The design procedure is exemplified in the synthesis of a novel configuration, which is further analyzed by the moment method.
Identification and Analysis of Robot Manipulator Singularities

The existence of singular positions inside the robot workspace is an inherent problem for task planning and robot control. At manipulator configurations near singular positions, very large joint motions are required to produce relatively small end-effector displacements. In the limit, when a singularity is encountered, the required joint motions become unbounded and the manipulator loses at least one degree of freedom. Identify ing the singularities in the robot workspace is not always an analytically tractable problem, except for manipulators with op portune placement of the joint axes. Typically, it is easier and more informative to evaluate the robot "arm" and "wrist" sin gularities, which reflect the limitations of the lower-order robot subsystems responsible for positioning and orienting, respec tively, the end effector in space. The objective of this article is to define analytically the interplay between the individual "arm" and "wrist" singularities and the global manipulator singularities. Specifically, a general formula that defines ma nipulator singularities in terms of the subsystem singularities is developed. The analysis leads to a novel, efficient method for identifying the singularities of six-axis manipulators. This is then illustrated through an example.
Eisen im alternden Gehirn

Eisen ist ein essenzielles Spurenelement für viele Stoffwechselwege des menschlichen Körpers. Der Grund für seine Bedeutung liegt darin, dass Eisen sowohl in 2wertiger als auch in 3-wertiger Form in wässriger Lösung stabil ist. Daher ist es ideal geeignet, um bei Redoxprozessen Elektronen abzugeben und wieder aufzunehmen. Allerdings ergibt sich daraus auch die Gefahr oxidativer Schädigungen. Physiologisch ermöglicht Eisen z. B. den Transport von Sauerstoff durch Hämoglobin und die oxidative Phosphorylierung der mitochondrialen Atmungskette [1]. Im Zentralnervensystem erfolgt die Synthese wichtiger Neurotransmitter eisenabhängig [2, 3]. Außerdem ist Eisen relevant für die Myelinisierung: Bei Kindern mit Eisenmangelanämie können Latenzverzögerungen für visuell und akustisch evozierte Potenziale als Zeichen von Hypomyelinisierung nachgewiesen werden [4]. Eisen wird intestinal als Fe2+ mithilfe des DMT1 (Divalent Metal Transporter 1) [5] oder als Häm-Eisen mittels des Transporters HCP1 (Haem Carrier Protein 1) [6] in die Enterozyten aufgenommen. Basolateral wird es über Ferroportin in das Blut abgegeben [7].
Analytical study of carrier photogeneration and photocurrent in thin silicon solar cells with specular and diffuse back reflection

An analytical study of the effect of back reflection in thin silicon solar cells implementing a practical (nonideal) diffuse reflector at the back side is presented. Both the diffuse and specular reflection components are considered. The reflection properties of the back reflector are described by means of three parameters, which are interpreted in terms of a simple physical model. An exact expression for the generation profile resulting from specular and diffuse reflections is derived and its dependence on the reflector parameters is studied. A mechanism through which specular reflection can significantly enhance light trapping in the case of relatively weak diffuse reflection is proposed. The photocurrent boost doe to both types of reflections acting simultaneously is estimated.
Active actuator fault‐tolerant control of a wind turbine benchmark model

This paper describes the design of an active fault‐tolerant control scheme that is applied to the actuator of a wind turbine benchmark. The methodology is based on adaptive filters obtained via the nonlinear geometric approach, which allows to obtain interesting decoupling property with respect to uncertainty affecting the wind turbine system. The controller accommodation scheme exploits the on‐line estimate of the actuator fault signal generated by the adaptive filters. The nonlinearity of the wind turbine model is described by the mapping to the power conversion ratio from tip‐speed ratio and blade pitch angles. This mapping represents the aerodynamic uncertainty, and usually is not known in analytical form, but in general represented by approximated two‐dimensional maps (i.e. look‐up tables). Therefore, this paper suggests a scheme to estimate this power conversion ratio in an analytical form by means of a two‐dimensional polynomial, which is subsequently used for designing the active fault‐tolerant control scheme. The wind turbine power generating unit of a grid is considered as a benchmark to show the design procedure, including the aspects of the nonlinear disturbance decoupling method, as well as the viability of the proposed approach. Extensive simulations of the benchmark process are practical tools for assessing experimentally the features of the developed actuator fault‐tolerant control scheme, in the presence of modelling and measurement errors. Comparisons with different fault‐tolerant schemes serve to highlight the advantages and drawbacks of the proposed methodology. Copyright © 2013 John Wiley & Sons, Ltd.
Homoclinic and heteroclinic orbits in the double scroll attractor

Chua, Matsumoto, and others have reported extensive simulation studies on a piecewise-linear model of a simple circuit. There is strong numerical and experimental evidence for chaotic behavior. This paper shows that the observed behavior can be understood using the theory of Shil'nikov bifurcations of homoclinic and heteroclinic orbits.
Präklinische Aspekte der HWS-Immobilisation

Die Anlage einer HWS-Orthese ist Gegenstand aktueller Fachdiskussion. In vielen Köpfen des präklinischen Personals ist eine Denkweise fest verankert, nach welcher ein Trauma mit vermuteter Verletzung der Halswirbelsäule stets mittels Zervikalstütze gesichert werden muss. Doch die Immobilisation der HWS bietet auch nennenswerte Nachteile für den Patienten. So findet gegenwärtig ein Umdenken in der Relevanz der Maßnahme statt.
Investigating insecticide susceptibility status of adult mosquitoes against some class of insecticides in Osogbo metropolis, Osun State, Nigeria

The study evaluates the resistance and susceptibility of adult female Anopheles gambiae s. l. , Aedes aegypti and Culex quinquefasciatus mosquitoes sourced within Osogbo metropolis, Osun State, Nigeria to four groups of insecticides [Permethrin, Deltamethrin, Pirimiphos-methyl and DDT (Dichlorodiphenyltrichloroethan)] and the distribution of their larval habitat within the metropolis. Mosquito larvae of the three genera were collected during the wet season and reared to adult stage in the laboratory. Emerged adult female mosquitoes were exposed to insecticide impregnated papers of the four insecticide groups for 60mins using WHO kits to determine the knock down rate (kdr). Thereafter, they were to holding tubes and left for 24hrs to assess their resistance and susceptibility according to the WHO protocol. Four types of larval habitats were identified (tires, ground pools, gutters and plastic containers). Anopheles gambiae s. l. showed the greatest resistance to Permethrin (49%) (p=0.04, p<0.05) while the highest susceptibility was recorded with Pirimiphos-methyl (69%) with the lowest against Permethrin (16%) (P=0.002; p<0.05). The greatest resistance of A. aegypti was against OC-Control (45%) (p=0.031; p<0.05). Permethrin had the highest susceptibility (60%) against A. aegypti while OC-control had the lowest (11%) (p= 0.005; p< 0.05). Culex quinquefasciatus had a lesser resistance to OC-control (38%) as compared with Aedes aegypti (45%). However, it was most least susceptible to Pirimiphos-methyl (52%) and DDT (17%) respectively (p=0.013; p<0.05). The susceptibility of A. gambiae s. l. and C. quinquefasciatus to Pirimiphos-methyl and A. aegypti to Permethrin is an indication of the possibility of success if employed for vector control of A. gambiae s. l. , C. quinquefasciatus and A. aegypti respectively. This could be through their inclusion as active ingredients in insecticide treated nets (ITNs) and indoor residual spray (IRS) with a view to abating malaria and other life-threatening mosquito-borne diseases constituting global public health scourge.
Dynamics of Zonal-Mean Flow Assimilation and Implications for Winter Circulation Anomalies.

Seasonally averaged 200-mb circulations for recent winters (1987/88 and 1988/89) that represent opposite phases of El Nino and a zonal-mean zonal flow index cycle are diagnosed using data assimilated by the Goddard Earth Observing System (GEOS) and operational analyses of the European Centre for Medium-Range Weather Forecasts (ECMWF). The comparison is undertaken to determine whether there are significant differences in the 200-mb vorticity dynamics implied by the mean meridional circulations in the two datasets and whether these differences can be related to the Incremental Analysis Update (IAU) method used in the GEOS assimilation. The two datasets show a high degree of similarity in their depictions of the large-scale rotational flow, but there are substantial differences in the associated divergent circulations. For the zonal-mean flow, the zonal winds are substantially the same, but the meridional wind in the Tropics and subtropics is considerably weaker in the GEOS assimilation than its counterparts in both the ECMWF data and the GEOS analyses used to produce the assimilation. The authors examine the assimilation of the Hadley circulation using a zonally symmetric f-plane model. For this model, the IAU method easily assimilates the rotational flow but fails to assimilate the divergent circulation. This deficiency of the IAU method may explain the weakness of the Hadley cell in the GEOS assimilation, at least in relation to the GEOS analysis. For this simple model, an alternative assimilation method, based on constraints imposed by the analyzed potential vorticity and mean meridional circulation fields, is proposed that simultaneously assimilates both rotational and divergent flow components. Barotropic modeling suggests that an accurate representation of mean meridional flow anomalies can be important for the diagnosis of both zonal-mean and eddy rotational flow perturbations, particularly during extreme phases of the zonal-mean zonal flow fluctuation.
High‐resolution limited‐area ensemble predictions based on low‐resolution targeted singular vectors

The operational limited‐area model, HIRLAM, at the Norwegian Meteorological Institute is used at 0.25° latitude/longitude resolution for ensemble weather prediction over Northern Europe and adjacent parts of the North Atlantic Ocean; this system is called LAMEPS. Initial and lateral boundary perturbations are taken from coarse‐resolution European Centre for Medium‐Range Weather Forecasts global ensemble members based on targeted singular vectors (TEPS). Five winter and five summer cases in 1997 consisting of 20 ensemble members plus one control forecast are integrated. Two sets of ensembles are generated, one for which both initial and lateral boundary conditions are perturbed, and another with only the initial fields perturbed. The LAMEPS results are compared to those of TEPS using the following measures: r.m.s. ensemble spread of 500 hPa geopotential height; r.m.s. ensemble spread of mean‐sea‐level pressure; Brier Skill Scores (BSS); Relative Operating Characteristic (ROC) curves; and cost/loss analyses. For forecasts longer than 12 hours, all measures show that perturbing the boundary fields is crucial for the performance of LAMEPS. For the winter cases TEPS has slightly larger ensemble spread than LAMEPS, but this is reversed for the summer cases. Results from BSS, ROC and cost/loss analyses show that LAMEPS performed considerably better than TEPS for precipitation, a result that is promising for forecasting extreme precipitation amounts. We believe this result to be linked to the high predictability of mesoscale flows controlled by complex topography. For two‐metre temperature, however, TEPS frequently performed better than LAMEPS. Copyright © 2002 Royal Meteorological Society
Polar Gap Dynamics and the Death Line of Millisecond Pulsars

Pulsar polar gaps are considered in which the potential drop is a significant fraction of that induced by the rotation of the neutron star. Such gaps are required in order for the observed restriction in the distribution of magnetic field strengths (B) and periods (P) in normal pulsars to be attributed to a death line beyond which the pulsar emission mechanism ceases to operate. It is shown that in contrast to normal pulsars, in which curvature radiation determines the death line, for millisecond pulsars synchrotron radiation is the dominant emission mechanism. The resulting death line is shifted to shorter periods by a factor ~3, as compared to an extrapolation of the death line for normal pulsars. The magnitude of this shift is quite model independent, since it is determined by the diterent properties of the two emission mechanisms. The transition between these different parts of the death line is caused by radiative reaction and occurs for B ~ 109–1010 G. A hitherto neglected effect forces a steepening of the death line for B ≳ 1012 G. Although quite model dependent, the same effect can account for the lack of observed millisecond pulsars with B ≲ 108 G. Except for the transition region, the location of the death line is insensitive to whether the polar gap breaks down or not. On the other hand, it is argued that both observational and theoretical results are reconciled best with a gap that breaks down, albeit only over a limited portion of the polar cap. The resemblance of the derived death line to the limits of the observed distribution of millisecond pulsars suggests that the observed values of magnetic field strengths and periods are due to the dynamics of the polar gap and not to restrictions imposed during their formation process. Since a large fraction of millisecond pulsars lie close to the derived death line, a significant number of neutron stars may exist that are not observed as millisecond pulsars. This makes the birth rate discrepancy between millisecond pulsars and their assumed low-mass X-ray binary progenitors more acute.
Fixing TCP Slow Start for Slow Fat Links

TCP slow start is designed to begin at a conservative bitrate, but quickly ramp up to the available bandwidth. Unfortunately, current default Linux TCP socket buffer sizes impede slow start bitrates on large bandwidth-delay product (BDP) links. However, even with our recommended socket buffer sizes in place, traditional slow start does not work well on large BDP links such as satellites, often overshooting and causing significant packet loss. Conversely, TCP HyStart (on by default in Linux), intended to avoid overshooting during slow start, can exit from slow start prematurely which is especially detrimental to utilization on large BDP links. This paper proposes adjustments to TCP slow start that ﬁnd a safe point to enter congestion avoidance without overshooting, while also avoiding premature exiting that degrades link utilization on large BDP links. We evaluate the proposed slow start algorithm over a commercial geostationary satellite link and our preliminary results indicate that our proposed slow start adjustments improve start-up performance, outperforming the measured alternatives.
Probabilistic context-free grammar for pattern detection in protein sequences

Analysis of protein sequences to predict their functions is a very challenging problem where pattern recognition techniques based on Hidden Markov models (HMMs) have proved to be the most efficient. However HMMs have limitations. According to formal language theory, their expressive power is similar to Probabilistic Regular Grammars (PRG). Here, we propose a pattern recognition method based on a more powerful grammar. We developed a Probabilistic Context-Free Grammar (PCFG) based system to detect protein regions that are involved in binding sites. In order to deal with the size of the protein alphabet, we use quantitative properties of amino acids to reduce the number of rules. The grammars based on different properties are then combined to retain as much inforination as possible. To increase the number of symbols while keeping the rule set on a maintainable level, we imposed some structural constraints on grammars. Moreover, to deal with motifs of a variable length, we implemented a window-independent scoring scheme for parsing. Then the PCFGs can be generated by an evolutionary process. It was customised to PCFG induction by implementing a diversity measure based on the Weighted Hamming distance. Our PCFGs proved their ability to detect binding sites with high accuracy. They achieved very good results for protein sequence annotation and binding site localisation. We also showed that some features of protein patterns could be better represented by PCFG than PRG. This confirms our initial assumption that binding site detection benefits from the expressive power provided by a context-free language. Finally, results suggest that, unlike current state-of-the-art methods, our system would be particularly suited to deal with patterns shared by non-homologous proteins.
Dynamic compensation method for multivariable control systems with saturating actuators

This paper proposes a dynamic compensation method for multivariable control systems with saturating actuators to cope with the reset windup phenomenon. A dynamic compensator is explicitly determined based on a performance index of controller states. The proposed method is applicable to any open-loop stable plants with saturating actuators whose controller has been determined by some design technique. A simulation example is included to illustrate the effectiveness of the proposed method. >
Waves In Fluids

This is a reissue in the Cambridge Mathematical Library series of a book first published in 1978. When it was first issued, it had enormous impact on all those working in fluid flows, and on waves in particular. I quote from the review by D C Pack, published in 1979 in the Journal of Fluid Mechanics (vol 90, pp 605-8): ``The book will become a standard work for reading and consultation by all interested in fluid flow. It will be invaluable to research students . Even among the most experienced readers few, if any, will fail to find in it new insights . comments and comparisons that illuminate the chapters. '' The same comments can be made today, because in spite of the two and a half decades that have now passed, it retains its immediacy and vitality. The book is designed to develop the fundamental concepts of waves in fluids through an in-depth analysis, in each of four chapters, of four important and representative examples of waves in fluids, namely, sound waves, one-dimensional waves, water waves and internal waves. A major highlight of the book is the thorough treatment of group velocity and ray-tracing ideas, developed throughout the text and with a climax in chapter four. As a potential textbook, or simply as an invaluable research aid, it remains indispensable. However, it does not cover such major developments in the last two decades as solitons, and the role of canonical equations such as the Korteweg-de Vries equation and the nonlinear Schrodinger equation. Hence it will need to be used in conjunction with more recent texts which cover these topics. R Grimshaw
The Monterey Area Ship Track Experiment

In June 1994 the Monterey Area Ship Track (MAST) experiment was conducted off the coast of California to investigate the processes behind anthropogenic modification of cloud albedo. The motivation for the MAST experiment is described here, as well as details of the experimental design. Measurement platforms and strategies are explained, and a summary of experiment operations is presented. The experiment produced the largest dataset to date of direct measurements of the effects of ships on the microphysics and radiative properties of marine stratocumulus clouds as an analog for the indirect effects of anthropogenic pollution on cloud albedo.
Resilience Through Appropriation: Pilots’ View on Complex Decision Support

Intelligent decision support tools (DSTs) hold the promise to improve the quality of human decision-making in challenging situations like diversions in aviation. To achieve these improvements, a common goal in DST design is to calibrate decision makers’ trust in the system. However, this perspective is mostly informed by controlled studies and might not fully reflect the real-world complexity of diversions. In order to understand how DSTs can be beneficial in the view of those who have the best understanding of the complexity of diversions, we interviewed professional pilots. To facilitate discussions, we built two low-fidelity prototypes, each representing a different role a DST could assume: (a) actively suggesting and ranking airports based on pilot-specified criteria, and (b) unobtrusively hinting at data points the pilot should be aware of. We find that while pilots would not blindly trust a DST, they at the same time reject deliberate trust calibration in the moment of the decision. We revisit appropriation as a lens to understand this seeming contradiction as well as a range of means to enable appropriation. Aside from the commonly considered need for transparency, these include directability and continuous support throughout the entire decision process. Based on our design exploration, we encourage to expand the view on DST design beyond trust calibration at the point of the actual decision.
Deep Dag Learning of Effective Brain Connectivity for FMRI Analysis

Functional magnetic resonance imaging (fMRI) has become one of the most common imaging modalities for brain function analysis. Recently, graph neural networks (GNN) have been adopted for fMRI analysis with superior performance. Unfortunately, traditional functional brain networks are mainly constructed based on similarities among region of interests (ROIs), which are noisy and can lead to inferior results for GNN models. To better adapt GNNs for fMRI analysis, we propose DABNet, a Deep DAG learning framework based on Brain Networks for fMRI analysis. DABNet adopts a brain network generator module, which harnesses the DAG learning approach to transform the raw time-series into effective brain connectivities. Experiments on two fMRI datasets demonstrate the efficacy of DABNet. The generated brain networks also highlight the prediction-related brain regions and thus provide interpretations for predictions.