Miracle-dz/UniFAR-FTUs huggingface dataset:
Model predictive control algorithms for active vibration control: a study on timing, performance and implementation properties

The dynamic properties of vibration control systems pose unique requirements and challenges on the implementation of model predictive control (MPC) algorithms with stability and feasibility guarantees. This article presents a comprehensive experimental comparison of computation timing and damping performance for various MPC methods; analyzing their offline and online properties in active vibration control and their impact on practical implementability. Optimal and sub-optimal MPC algorithms providing guaranteed stability and constraint feasibility have been applied to the real-time active vibration attenuation of a lightly damped mechanical test structure. Based on the experiments presented in this paper, the standard and sequential quadratic programming-based, optimal and sub-optimal minimum time multi-parametric programming-based and the sub-optimal Newton–Raphson’s algorithm-based MPC methods demonstrate closely comparable vibration attenuation performance. The offline and online timing analysis indicates that the underlying difference between the investigated MPC algorithms lies mainly in practical implementability difficulties caused by inherent algorithm efficiency, rendering certain variants of MPC more suitable for vibration control than others.
Spatially adaptive bases in wavelet-based coding of semi-regular meshes

In this paper we present a wavelet-based coding approach for semi-regular meshes, which spatially adapts the employed wavelet basis in the wavelet transformation of the mesh. The spatially-adaptive nature of the transform requires additional information to be stored in the bit-stream in order to allow the reconstruction of the transformed mesh at the decoder side. In order to limit this overhead, the mesh is first segmented into regions of approximately equal size. For each spatial region, a predictor is selected in a rate-distortion optimal manner by using a Lagrangian rate-distortion optimization technique. When compared against the classical wavelet transform employing the butterfly subdivision filter, experiments reveal that the proposed spatially-adaptive wavelet transform significantly decreases the energy of the wavelet coefficients for all subbands. Preliminary results show also that employing the proposed transform for the lowest-resolution subband systematically yields improved compression performance at low-to-medium bit-rates. For the Venus and Rabbit test models the compression improvements add up to 1.47 dB and 0.95 dB, respectively.
Information sharing in supply chains: Incentives for information distortion

The existing literature on supply chain information sharing assumes that information is shared truthfully. Unless each party can verify the authenticity of the other party's information, manufacturers and retailers may divulge false information for their own benefit. These information distortions may reduce the benefit levels or even stop information sharing in supply chains. We analyze the incentives for manufacturers and retailers within a supply chain to distort information when they share it and propose a mechanism that results in truthful information sharing. We consider a make-to-order supply chain consisting of a single manufacturer and a single retailer. The manufacturer and the retailer set prices based on their private forecasts of uncertain demand. If both parties share their forecasts truthfully, the manufacturer always benefits; however, the retailer benefits only if the manufacturer sets a lower wholesale price when information is shared compared to when information is not shared. However, we show that the manufacturer and the retailer, respectively, have an incentive to overstate and understate their forecasts while sharing information. The information distortion phenomenon is the direct result of each party exploiting its private information to appropriate the gains from information sharing. We show that the incentives to distort information are eliminated and both parties benefit from information sharing if the manufacturer and the retailer can agree on their relative profit margins prior to information sharing.
Current-induced terahertz oscillations in plasmonic crystal

We discuss a possible mechanism of the current instability in multi-gated structures with periodic modulation of the electron density in the device channel. In such structures, the plasma wave velocity is periodically modulated as well, and the stationary electric current may become unstable with respect to generation of the plasma oscillations. In the simplest model of periodically alternating stripes of the electron density with plasma wave velocities sa and sb, respectively (sa < sb), the instability occurs when the electron drift velocity approaches sa. For typical parameters, the plasma oscillation frequency can be tuned to be in the terahertz range of frequencies.We discuss a possible mechanism of the current instability in multi-gated structures with periodic modulation of the electron density in the device channel. In such structures, the plasma wave velocity is periodically modulated as well, and the stationary electric current may become unstable with respect to generation of the plasma oscillations. In the simplest model of periodically alternating stripes of the electron density with plasma wave velocities sa and sb, respectively (sa < sb), the instability occurs when the electron drift velocity approaches sa. For typical parameters, the plasma oscillation frequency can be tuned to be in the terahertz range of frequencies.
Difficulties with Inflationary Cosmology a

The problems posed for inflationary cosmological models by (1) the large-scale homogeneity of the universe and (2) the second law of thermodynamics are considered theoretically. The analyses of Penrose (1979, 1981, 1988, and 1989) are summarized and illustrated with graphs and diagrams. Particular attention is given to the definition of entropy in the cosmological context, gravitational entropy, the low entropy of the big bang, and the Weyl curvature hypothesis. 23 refs.
Random fixed point theorem for multivalued nonexpansive operators in Uniformly nonsquare Banach spaces

Let (Ω, Σ) be a measurable space, with Σ a sigma-algebra of subset of Ω, and let C be a nonempty bounded closed convex and separable subset of a Banach space X, satisfying Dominguez-Lorenzo condition, KC(X) the family of all compact convex subsets of X . We prove that a 1 -χ contractive mutivalued nonexpansive random operator from C into KC(X ) satisfying an inwardness condition has a random fixed point. Furthermore, we also prove that a uniformly nonsquare Banach spaces with property WORTH has a random fixed point for multivalued nonexpansive non-self random operators.
On the global convergence of trust region algorithms using inexact gradient information

Trust region algorithms are an important class of methods that can be used to solve unconstrained optimization problems. Strong global convergence results are demonstrated for a class of methods where the gradient values are approximated rather than computed exactly, provided they obey a simple relative error condition. No requirement is made that gradients be recomputed to successively greater accuracy after unsuccessful iterations.
The HWRF Hurricane Ensemble Data Assimilation System (HEDAS) for High-Resolution Data: The Impact of Airborne Doppler Radar Observations in an OSSE

AbstractWithin the National Oceanic and Atmospheric Administration, the Hurricane Research Division of the Atlantic Oceanographic and Meteorological Laboratory has developed the Hurricane Weather Research and Forecasting (HWRF) Ensemble Data Assimilation System (HEDAS) to assimilate hurricane inner-core observations for high-resolution vortex initialization. HEDAS is based on a serial implementation of the square root ensemble Kalman filter. HWRF is configured with a horizontal grid spacing of km on the outer/inner domains. In this preliminary study, airborne Doppler radar radial wind observations are simulated from a higher-resolution km version of the same model with other modifications that resulted in appreciable model error.A 24-h nature run simulation of Hurricane Paloma was initialized at 1200 UTC 7 November 2008 and produced a realistic, category-2-strength hurricane vortex. The impact of assimilating Doppler wind observations is assessed in observation space as well as in model space. It is obser.
Evaluation of Model Based Testing and Conformiq Qtronic

ion from Quality-of-Service principle is often used to abstract from concerns such as timing, security, memory consumption, etc. 1. 2.2 Model Redundancy The MBT can be applied in many different scenarios. The difference among these scenarios is in redundancy level of model. Sometimes one model is used for both test cases and code generation. Another case is that when the separate models are used for testing and code generation. Following sections will illustrate the above two scenarios.
Electronic structure of the interface of aluminum nitride with Si(100)

The band alignment at the interfaces of Si(100) with amorphous (a-) and crystallized (c-) AlN layers was analyzed using internal photoemission and photoconductivity spectroscopy. The bandgap of thin a-AlN layers grown using atomic layer deposition is found to be 5.8±0.1 eV, widening to 6.5±0.2 eV after annealing induced crystallization into the wurtzite phase. Internal photoemission of electrons from the Si valence band to the AlN conduction band was found to exhibit the same energy threshold of 3.2±0.1 eV in amorphous and crystallized AlN. The energy band diagrams of a-AlN/Si(100) and c−AlN/Si(100) interfaces are established.The band alignment at the interfaces of Si(100) with amorphous (a-) and crystallized (c-) AlN layers was analyzed using internal photoemission and photoconductivity spectroscopy. The bandgap of thin a-AlN layers grown using atomic layer deposition is found to be 5.8±0.1 eV, widening to 6.5±0.2 eV after annealing induced crystallization into the wurtzite phase. Internal photoemission of electrons from the Si valence band to the AlN conduction band was found to exhibit the same energy threshold of 3.2±0.1 eV in amorphous and crystallized AlN. The energy band diagrams of a-AlN/Si(100) and c−AlN/Si(100) interfaces are established.
An experimental investigation of disturbance amplification in external laminar natural convection flow

An experimental investigation has been carried out on the nature of disturbance amplification in the laminar natural convection boundary layer formed on a vertical flat surface with uniform heat flux input. A pair of calibrated hot-wire anemometers were used to obtain amplitude and phase profiles of disturbance velocities and to measure the distance amplification rate as a function of disturbance frequency. An interferometer was used to measure the amplitude and phase profiles of disturbances in the temperature field. The relative amplification of a temperature disturbance was measured as it was convected downstream. For this latter measurement a technique employing interferometric moiré patterns was used. All of these measurements are in good agreement with the theory. The results of this investigation further strengthen the conclusions drawn in an earlier theoretical investigation, that the frequencies which amplify fastest and lead to transition and turbulence occupy a band much higher than the frequencies which begin to amplify first. These results also support stability theory in the very close agreement between calculated and measured distributions of disturbance quantities.
The sensitivity and evolutionary trajectory of the mountain cryosphere: Implications for mountain geomorphic systems and hazards

Global climate change gives rise to changing spatial patterns of snow and ice, especially over mountain blocks where orographic and synoptic circulation effects play significant roles in creating patterns of precipitation and glacier development. The presence of snow and ice results in heat balance changes and other land surface feedbacks that have implications for patterns of mountain glacier retreat and the dynamics of mountain geomorphic systems. This study considers the sensitivity of the mountain cryosphere (snow, ice, permafrost) to global climate change, and the implications of this sensitivity analysis for evaluating mountain surface stability, geomorphic change, and the generation of mountain geohazards. Consideration of these issues is informed by evidence from case studies reported in the literature and by field observations of mountain system dynamics worldwide. Results show that ‘sensitivity’ to climate forcing has been interpreted and defined in different ways in mountain snow, ice, and permafrost systems, with respect to properties such as albedo, mass balance or rapidity of system change. There are also significant spatial differences in sensitivity between different mountain blocks for snow, ice and permafrost, and these regions are therefore likely to follow different trajectories of geomorphic change in response to climate forcing, related to their physiographic properties and the extent of cryospheric coverage. Within glaciated mountains in particular, the relative timing of different geomorphic events, and the interplay between slope, glacier front, and proglacial sediment sources and environments, may vary depending on glacier size, geomorphic setting, and microclimate. By contrast, responses to permafrost warming (increased surface instability and mass movements) and changes in snow patterns (avalanche risk, floods) may have quite different spatial and temporal patterns and influenced by different environmental controls. An integrated evolutionary model for mountain system development under a changing cryosphere is proposed, highlighting the critical role of energy balance as a forcing factor that then triggers downstream mountain system responses. This suggests that different elements of mountain systems exhibit different sensitivities, and furthermore that these sensitivities change over time and space through the period of anthropogenic global warming and paraglacial relaxation.
Thermal conductivity anisotropy and grain structure in Ge2Sb2Te5 films

Although lateral thermal conduction in Ge2Sb2Te5 (GST) films can influence the performance of phase change memory (PCM), there are no data available for the in-plane thermal conductivity. This work measures both the in-plane and the out-of-plane thermal conductivities for the amorphous, face-centered-cubic, and hexagonal-close-packed phases of GST using two independent techniques. For crystalline GST, we report anisotropy favoring out-of-plane conduction by up to 54%, which varies with annealing time. Scaling arguments indicate that the anisotropy may be due to the thermal resistance of amorphous regions near grain boundaries. This explanation is consistent with transmission electron microscopy images showing columnar grains and amorphous phase at grain boundaries.
High-T-c superconducting quantum interference device recordings of spontaneous brain activity: Towards high-T-c magnetoencephalography

We have performed single-and two-channel high transition temperature (high-T-c) superconducting quantum interference device (SQUID) magnetoencephalography (MEG) recordings of spontaneous brain activity in two healthy human subjects. We demonstrate modulation of two well-known brain rhythms: the occipital alpha rhythm and the mu rhythm found in the motor cortex. We further show that despite higher noise-levels compared to their low-T-c counterparts, high-T-c SQUIDs can be used to detect and record physiologically relevant brain rhythms with comparable signal-to-noise ratios. These results indicate the utility of high-T-c technology in MEG recordings of a broader range of brain activity.
Characterizing coastal phytoplankton seasonal succession patterns on the West Antarctic Peninsula

In coastal West Antarctic Peninsula (WAP) waters, large phytoplankton blooms in late austral spring fuel a highly productive marine ecosystem. However, WAP atmospheric and oceanic temperatures are rising, winter sea ice extent and duration are decreasing, and summer phytoplankton biomass in the northern WAP has decreased and shifted toward smaller cells. To better understand these relationships, an Imaging FlowCytobot was used to characterize seasonal (spring to autumn) phytoplankton community composition and cell size during a low (2017–2018) and high (2018–2019) chlorophyll a year in relation to physical drivers (e.g., sea ice and meteoric water) at Palmer Station, Antarctica. A shorter sea ice season with early rapid retreat resulted in low phytoplankton biomass with a low proportion of diatoms (2017–2018), while a longer sea ice season with late protracted retreat resulted in the opposite (2018–2019). Despite these differences, phytoplankton seasonal succession was similar in both years: (1) a large‐celled centric diatom bloom during spring sea ice retreat; (2) a peak summer phase comprised of mixotrophic cryptophytes with increases in light and postbloom organic matter; and (3) a late summer phase comprised of small (< 20 μm) diatoms and mixed flagellates with increases in wind‐driven nutrient resuspension. In addition, cell diameter decreased from November to April with increases in meteoric water in both years. The tight coupling between sea ice, meltwater, and phytoplankton species composition suggests that continued warming in the WAP will affect phytoplankton seasonal dynamics, and subsequently seasonal food web dynamics.
NUMERICAL STUDY OF A TRANSIENT GAS AND PARTICLE FLOW IN A HIGH-SPEED NEEDLE-FREE BALLISTIC PARTICULATE VACCINE DELIVERY SYSTEM

A unique biolistic method of vaccination is operated by accelerating particulate vaccines with a high-speed gas jet generated by a convergent-divergent conical nozzle to sufficient momentum to penetrate the outer layer of human skin. The targeted cells elicit an immunological response. In this paper, Computational Fluid Dynamics (CFD) is utilized to simulate the operation of a prototype biolistics delivery system. The key features of transient gas dynamics and gas-particle interaction are discussed.
Numerical simulation of the haemodynamics in end‐to‐side anastomoses

In this paper, the commercial CFD package Ansys workbench 11 was used to analyse the three‐dimensional haemodynamics of a typical stenotic Coronary Artery Bypass Grafting (CABG). Two end‐to‐side CABG configurations with anastomosis angle of 20∘ and 40∘ and graft–artery diameter ratios of 1/0.6, 1/1 and 1/1.6 were examined. The flow measurements from in vitro Doppler guide wire technique acquired in left interior mammary artery (LIMA) and grafted to the left anterior descending artery (LAD) were used to impose the physiologically flow conditions at proximal and distal CABG inlet and outlet, respectively. The blood flow was considered to be incompressible, pulsatile, Newtonian, and laminar rheology. The main objective was to determine the effect of anastomosis angle and graft–artery diameter ratio on the flow patterns and the long‐term functionality of the graft. In analysing the results, the distributions of temporal and spatial wall shear stress (WSS) gradient and oscillating shear index (OSI) in the critical regions of CABG such as heel, toe and the centre of the junction were presented and the vortex motions and the occurrence of recirculation zones were examined. The findings showed asymmetrically disturbed flows in the localized regions of the proximal and distal host artery for all models considered and the movement of the recirculation zones from heel to toe was found to depend on the time at the cardiac cycle. These regions are known as susceptible sites to thrombosis and re‐stenosis due to their association with low values of WSS. Copyright © 2010 John Wiley & Sons, Ltd.
Spatio‐Temporal Evolution of Aftershock and Repeater Source Properties After the 2016 Pedernales Earthquake (Ecuador)

Subduction zones are highly heterogeneous regions capable of hosting large earthquakes. To better constrain the processes at depth, we analyze the source properties of 1514 aftershocks of the 16th April 2016 Mw 7.8 Pedernales earthquake (Ecuador) using spectral ratios. We are able to retrieve accurate seismic moments, stress drops, and P and S corner frequencies for 341 aftershocks, including 136 events belonging to families of repeating earthquakes. We find that, for the studied magnitude range (Mw 2–4), stress drops appear to increase as a function of seismic moment. They are also found to depend on their distance to the trench. This is in part explained by the increase in depth, and therefore normal stress, away from the trench. However, even accounting for the shallow depths of earthquakes, stress drops appear to be anomalously low near the trench, which can be explained by a high pore fluid pressure or by inherent properties of the medium (low coefficient of friction/low rigidity of the medium) in that region. We are also able to examine the temporal evolution of source properties thanks to the presence of repeating earthquakes. We find that the variations of source properties within repeating earthquake families are not uniform, and are highly spatially variable over most of the study area. This is not the case near the trench, however, where stress drops systematically decrease over time. We suggest that this reflects an increase in pore fluid pressure near the trench over the postseismic period.
Four‐node semi‐EAS element in six‐field nonlinear theory of shells

We propose a new four‐node C0 finite element for shell structures undergoing unlimited translations and rotations. The considerations concern the general six‐field theory of shells with asymmetric strain measures in geometrically nonlinear static problems. The shell kinematics is of the two‐dimensional Cosserat continuum type and is described by two independent fields: the vector field for translations and the proper orthogonal tensor field for rotations. All three rotational parameters are treated here as independent. Hence, as a consequence of the shell theory, the proposed element has naturally six engineering degrees of freedom at each node, with the so‐called drilling rotation. This property makes the element suitable for analysis of shell structures containing folds, branches or intersections. To avoid locking phenomena we use the enhanced assumed strain (EAS) concept. We derive and linearize the modified Hu–Washizu principle for six‐field theory of shells. What makes the present approach original is the combination of EAS method with asymmetric membrane strain measures. Based on literature, we propose new enhancing field and specify the transformation matrix that accounts for the lack of symmetry. To gain knowledge about the suitability of this field for asymmetric strain measures and to assess the performance of the element, we solve typical benchmark examples with smooth geometry and examples involving orthogonal intersections of shell branches. Copyright © 2006 John Wiley & Sons, Ltd.
Teachers’ perspectives on teaching EFL speaking virtually: A case study of COVID-19 pandemic survival

The goals of this study are to analyze and provide in-depth detail about how teachers felt and how they taught during the COVID-19 pandemic. The study used a qualitative approach via the Atlas.ti application and used a semi-structured interview to collect data. Five teachers were recruited to answer the research questions to determine what they thought, how they felt, and what they did during the pandemic. To improve the consistency of theme analysis coding (validity or trustworthiness), the study was adjusted based on feedback from external independent reviewers. The results reveal that teaching speaking has a direct effect on four things: (1) the teaching method, (2) the teaching tools, (3) the goals or aims, and (4) how well the students do. As a result, pupils perform better academically, cognitively, and socio-emotionally. This study has flaws, such as the fact that it was conducted in a remote area with few facilities and only used a small sample of teachers with good digital literacy.