Miracle-dz/UniFAR-FTUs huggingface dataset:
Aerothermal analysis of the Phoebus capsule with radiative heating on the back body

In this paper, computational uid dynamic simulations are performed to simulate the aeroheating environment of both the frontbody and the afterbody of the Phoebus probe. The Phoebus mission is a high speed Earth re-entry planned by ESA for validation of instrumentation, materials and numerical tools, with a particular interest on the radiative component of the heat loads. Three points of the trajectory have been selected for analysis. They correspond to the predicted radiative peak heating, the convective peak heating and a higher density trajectory point. For each trajectory point, convective and radiative heat uxes have been computed. The length of the computational back domain and its in uence on the ow characteristics is also discussed in this paper.
Bayesian High-Rank Hankel Matrix Completion for Nonlinear Synchrophasor Data Recovery

Phasor measurement units (PMUs) provide high temporal-resolution synchrophasor measurements for power system monitoring and control. The frequent data quality issues, such as missing and bad data, prevent the incorporation of synchrophasor data in real-time operations. Most existing data-driven data recovery methods assume the power system dynamics can be approximated by a linear dynamical system, and the recovery performance degrades significantly when the power system is experiencing nonlinear dynamics during significant events. This paper proposes a data-driven Bayesian nonlinear synchrophasor data recovery method (Ba-NSDR) that can recover a consecutive time period of simultaneous data losses or errors across all channels, even when the underlying system is highly nonlinear. The idea is to lift the Hankel matrix of the spatial-temporal synchrophasor data to a higher dimension such that the lifted Hankel matrix is low-rank in that space and can be processed with the kernel trick. Our proposed Bayesian method then infers the probabilistic distributions of synchrophasor from the partial observations. Some distinctive features of Ba-NSDR include an uncertainty index to measure the accuracy of the recovery result and the robustness to parameter selections. Our method is verified on both synthetic and recorded event datasets.
Riblets in the viscous sublayer : Optimal Shape Design of Microstructures

Previous research has established that a smooth surface has not necessarily minimal drag: Many experiments by different laboratories, e.g. NASA and DLR Berlin, indicate that an extra surface layer with tiny grooves aligned in the stream-wise direction can be used to reduce the drag. The aim of this project is to find the optimal shape of such microstructures on surfaces of submerged bodies. We assume that these microstructures remain in the viscous sublayer where the flow equations are the 3D incompressible, steady state Navier-Stokes equations with a Couette in- and outflow determinated through two boundary conditions, the no-slip condition on the lower boundary and the friction condition on the upper one. The objective function of our optimization problem is the tangential drag force, which we want to minimize. Solving this problem is difficult because of the rough boundary, which causes a big amount of data. We apply homogenization theory and replace the rough boundary by a smooth one, where the right boundary conditions have been determined. Furthermore, our optimization problem can be simplified using this approximation and we end up minimizing a scalar size, the Navier constant, which is calculated using the velocity of an auxiliary boundary layer equation. To solve the optimization problem we use sensitivity-based optimization methods. The sensitivity is calculated analytically and we use it to determine the gradient of the cost function with respect to the design variable. A minimum is sought by using the steepest descent algorithm with step size according to Armijo rule. The necessary optimality conditions are derived and a sequence of admissible domains is built which tends to the optimal solution. The state equations are solved numerically using finite elements on unstructured grids and multigrid algorithms. The results obtained with this approach give us a drag reduction of approximately 2-6% relative to the drag of the smooth configuration.
3D models of glioblastoma interaction with cortical cells

Introduction: Glioblastoma (GBM) invasiveness and ability to infiltrate deep into the brain tissue is a major reason for the poor patient prognosis for this type of brain cancer. Behavior of glioblastoma cells, including their motility, and expression of invasion-promoting genes such as matrix metalloprotease-2 (MMP2), are strongly influenced by normal cells found in the brain parenchyma. Cells such as neurons may also be influenced by the tumor, as many glioblastoma patients develop epilepsy. In vitro models of glioblastoma invasiveness are used to supplement animal models in a search for better treatments, and need to combine capability for high-throughput experiments with capturing bidirectional interactions between GBM and brain cells. Methods: In this work, two 3D in vitro models of GBM-cortical interactions were investigated. A matrix-free model was created by co-culturing GBM and cortical spheroids, and a matrix-based model was created by embedding cortical cells and a GBM spheroid in Matrigel. Results: Rapid GBM invasion occurred in the matrix-based model, and was enhanced by the presence of cortical cells. Little invasion occurred in the matrix-free model. In both types of models, presence of GBM cells resulted in a significant increase in paroxysmal neuronal activity. Discussion: Matrix-based model may be better suited for studying GBM invasion in an environment that includes cortical cells, while matrix-free model may be useful in investigation of tumor-associated epilepsy.
Electrical isolation of the right ventricular outflow tract in idiopathic ventricular tachycardia: a case report

Abstract Background Ventricular tachycardia (VT) originating in the right ventricular outflow tract (RVOT) is the most common form of idiopathic VT. Catheter ablation of right ventricular outflow tract tachycardia (RVOT-VT) is associated with high success rates. However, non-inducibility of VT on electrophysiological (EP) study can severely impact ablation outcome. We describe a novel catheter ablation strategy which proved feasible and safe in a case of highly symptomatic, non-inducible RVOT-VT. Case summary A 51-year-old male with a history of non-sustained VT (NSVT) was referred to our hospital after two syncopal episodes resulting in collapse. Upon admission, a cluster of monomorphic NSVT (250–270 b.p.m.) resulted in haemodynamic instability and required transfer to the intensive care unit. On twelve-lead electrocardiogram, NSVT showed inferior axis and left bundle branch block, suggestive of RVOT-VT. Diagnostic workup including echocardiography, coronary angiography, and late enhancement computed tomography (CT) revealed no evidence of structural heart disease. On two EP studies, non-inducibility of clinical VT despite repeated ventricular pacing and isoproterenol infusion rendered precise mapping of triggered activity unfeasible. Therefore, a bailout ablation strategy was developed by performing a circumferential electrical RVOT isolation using a 3.5 mm irrigated-tip ablation catheter under the guidance of high-density electroanatomic mapping (CARTO® 3) and CT reconstruction of cardiac anatomy. No procedural complications occurred, and the patient remained arrhythmia-free during a 6-month follow-up period. Discussion Catheter ablation is a first-line therapy for symptomatic and drug-refractory idiopathic RVOT-VT. Non-inducibility of RVOT-VT represents a relevant limitation for successful ablation which might be overcome by electrical RVOT isolation as a bailout ablation strategy.
Polymeric wavelength filters with polymer gratings

Wavelength filters with Bragg gratings are demonstrated based on low-loss polymer waveguides and high-refractive-index polymer gratings. Two kinds of fluorinated polymers, perfluorocyclobutane and fluorinated poly(arylene ethers) are used for the low-loss waveguide operating around the 1.55 μm wavelength. The polymer grating is made of Resole, and it is successfully integrated in the polymer waveguides. In order to fabricate the Bragg gratings on the polymer waveguides, we use a phase mask and a Hg lamp in a mask aligner as the illuminating source instead of the laser. This method provides uniform gratings on a large area as well as the alignment capability. In the fabricated wavelength filters, the reflectivity at the Bragg wavelength is 30 dB, the 3 dB bandwidth is as narrow as 0.6 nm, and the insertion loss is 3.7 dB.
Cancellation Problems and Dimension Theory

ABSTRACT A well-known cancellation problem of Zariski asks—for two given domains (fields, respectively) K 1 and K 2 over a field k—whether the k-isomorphism of K 1[t] (K(t), respectively) and K 2[t] (K 2(t), respectively) implies the k-isomorphism of K 1 and K 2. In this article, we address and systematically study a related problem: whether the k-embedding from K 1[t] (K 1(t), respectively) into K 2[t] (K 2(t), respectively) implies the k-embedding from K 1 into K 2. Our results are affirmative: if K 1 and K 2 are affine domains over an arbitrary field k, and K 1[t] can be k-embedded into K 2[t], then K 1 can be k-embedded into K 2; if K 1 and K 2 are affine fields over an arbitrary field k, and K 1(t) can be k-embedded into K 2(t), then K 1 can be k-embedded into K 2. Similar results are obtained for some general nonaffine domains and nonaffine fields. These results were obtained in Belov et al. (preprint) together with L. Makar-Limanov. In this article we give an alternative proof, show connection with dimension theory, consider the case of infinite transcendental degree, and present some applications and surroundings.
Study on Distributed Power-Collection and Cascaded Boosting-Voltage Topology and Strategy for Offshore DC Station

Different from traditional concentrated power-collection and boosting-voltage (CPCB) topology adopted by HVDC station, this paper adopts a distributed power-collection and cascaded boosting-voltage (DPCB) topology for offshore DC station to collect DC power and boost DC voltage, which consists of multiple cascaded single active bridges (SABs). It has merits of strong DC-voltage boosting ability, low design difficulty and cost, and low system error rate. Three aspects are studied as follows. First, DPCB topology with its circuit equations is deduced step by step, and its operational mechanism is analysed under phase-shifting control method further. Second, PI control strategy is designed based on system small signal model, and system performance is analyzed by Bode diagram. Third, fault tolerance strategy with predicted power ratio is designed to keep DPCB station from breakdown when some SABs and generators are out of order, and enormous power difference occurs due to the factors of wind turbine location and windward. Finally, the feasibility and effectiveness of designed DPCB station with its strategy are verified by experiment results.
Privacy-Preserving Federated Learning via Functional Encryption, Revisited

Federated Learning (FL), emerging as a distributed machine learning, is a popular paradigm that allows multiple users to collaboratively train an intermediate model by exchanging local models without the training data leaving each user’s domain. However, FL still suffer from privacy risk such as leaking private information from users’ uploaded local models. To address the privacy concern, several approaches have been proposed to achieve privacy-preserving FL (PPFL) based on differential privacy (DP), multi-party computation (MPC), homomorphic encryption (HE) and functional encryption (FE). Compared with DP, MPC and HE, approaches based on FE are more advantageous and thus become the focus of this work. Moreover, all existing PPFL schemes via FE employ a multi-user extension of FE for a specific function, i.e., multi-input FE (MIFE). In this paper, we point out that existing FE-based PPFL schemes have faced with several security issues due to the misuse of MIFE. After reconsidering the security requirements of PPFL, we propose new goals of designing PPFL using FE. To achieve our goals, we propose a new FE called dual-mode decentralized multi-client FE (2DMCFE) and give a concreate construction for 2DMCFE. With 2DMCFE, we propose a new framework of PPFL where we establish a fresh 2DMCFE instance for each subset of users. Security proof shows the strong security of our framework under the semi-honest security setting. Furthermore, experiments conducted on real dataset demonstrate that our framework achieves comparable model accuracy and training efficiency to the basic FE-based scheme while providing stronger security guarantee.
Virtual peer teaching in the gross anatomy lab: a format of peer teaching and learning during the COVID-19 pandemic

Background: Peer teaching is a powerful educational tool utilized in medical school curricula. Previously, first year medical students taught their peers about the gross anatomical structures they had dissected in the anatomy lab. While this strategy provided an opportunity for students to learn from one another, there were unintended outcomes including difficulty engaging all students. Considering these observations, along with needing to limit student numbers in the lab due to the coronavirus disease 2019 (COVID-19) pandemic, a strategy was developed where students could conduct their anatomy peer teaching in a virtual environment. The goal was to establish an effective and efficient means for students to teach and learn from one another virtually. Methods: Students, working in groups of four, were tasked to: 1) Find and label 4-5 assigned structures on cadaver-based images; 2) Provide a rationale for labeling; 3) Discuss something relevant about the structure; 4) Prepare a 5-minute video presentation of steps 1-3; and 5) Review and provide meaningful feedback on another group’s presentation. Student performance on virtual peer teaching assignments was evaluated using a structured rubric and grades were weighted based on two separate faculty assessments. Student feedback was obtained via discussions with the course director, a semi-structured 1-hour virtual focus interview and from course evaluation data. Results: While students performed well on these assignments, feedback from students indicated several drawbacks such as excess time editing their videos, concerns about the validity of information provided by their peers, and the timing of peer teaching to be non-conducive to learning. Conclusions: Although the students viewed the virtual peer teaching negatively, we were successful in developing a platform in which students participated more equally in peer teaching. Recommendations to those considering this platform include careful consideration of timing of peer teaching activities and faculty feedback as well as technology used.
Semi-local inversion of the geodesic ray transform in the hyperbolic plane

The inversion of the ray transform on the hyperbolic plane has applications in geophysical exploration and in medical imaging techniques (such as electrical impedance tomography). The geodesic ray transform has been studied in more general geometries and including attenuation, but all of the available inversion formulas require knowledge of the ray transform for all the geodesics. In this paper we present a different inversion formula for the ray transform on the hyperbolic plane, which has the advantage of only requiring knowledge of the ray transform in a reduced family of geodesics. The required family of geodesics is directly related to the set where the original function is to be recovered.
Gender Differences in the Frequency of Positive and Negative Effects after Acute Caffeine Consumption

Gender-specific caffeine-related adverse effects should be thoroughly investigated. Sixty-five adult participants were included in the study, 30 men and 35 women (age, 22.5 ± 2.8; body weight, 71.7 ± 16.2 kg; BMI, 23.6 ± 4.4). The participants who were classified as low and moderate caffeine users received 3 mg/kg, and high caffeine users received 6 mg/kg of caffeine in one dose. One hour after ingestion of caffeine and within twenty-four hours, the participants completed a side effect questionnaire. Effects after the ingestion of CAF were divided into two subgroups: negative (muscle soreness, increased urine output, tachycardia and palpitations, anxiety or nervousness, headache, gastrointestinal problems, and insomnia) and positive (perception improvement; increased vigor/activeness). Caffeine ingestion resulted in a statistically significant association between gender and negative effects one hour after ingestion (p = 0.049). Gender and positive effects one hour after ingestion (p = 0.005), and between gender and positive effects within 24 h after ingestion (p = 0.047). There were significant associations between gender and perception improvement (p = 0.032) and gender and increased vigor/activeness (p = 0.009) one hour after ingestion. Nearly 30% of men and 54% of women reported negative effects. At the same time, 20% of women and more than 50% of men reported positive effects. Gender is an important factor in the negative and positive effects of caffeine consumption.
Adiabatic Invariance of a Simple Oscillator

J. E. Littlewood [5] has derived asymptotic expressions, as $\varepsilon \to 0 + $, for the function $r^2 = \phi (\varepsilon \tau )u^2 + \phi ^{ - 1} (\varepsilon \tau )({{du} / {d\tau }})^2 $, when u is a solution of the differential equation ${{d^2 u} / {d\tau ^2 }} + \phi ^2 (\varepsilon \tau )u = 0$. He assumes that $\phi (\tau ) > 0$, $\phi ( \pm \infty ) > 0$, $\phi ^{(n)} ( \pm \infty ) = 0$, and $\phi ^{(n)} \in L( - \infty ,\infty ) 0$, for all $n > 0$. In the present paper, Littlewood’s results are re-proved and strengthened by using the established methods for the solution of differential equations by asymptotic series. A new result is an explicit series construction in powers of $\varepsilon $ for the function $r^2 $. Littlewood’s asymptotic expression was in terms of the unknown solution of the differential equation.
METHOD AND SOFTWARE COMPONENT MODEL FOR SKIN DISEASE DIAGNOSIS

Context. The problem of skin disease diagnosis was investigated in the paper. Its actuality is caused by the necessity of automation of at least advisory medical decision making. Such decisions are made in telemedicine, for instance, when skin disease diagnostics is performed under specific conditions. These conditions are specified by situations when data for analysis are collected but a qualified doctor has no possibility to process the data and to make a diagnosis decision based on it. The object of the study is a process of skin disease diagnosis. Objective. The objective of the study is to develop a skin disease diagnosis method to automate making of advisory medical diagnosis decisions and to increase efficiency of such decisions. Method. The skin disease diagnosis method was proposed in the work. This method applies the modified ResNet50 model. It was proposed to add layers to the ResNet50 model and to train it using transfer learning and fine-tuning techniques. The method also defines image processing in particular through the change of its resolution and uses oversampling technique to prepare a dataset for model training. Results. Experimental investigation of the proposed method was performed using the HAM10000 dataset which contains images of skin diseases. The images were collected using dermatoscopy method. The dataset contains observations for 7 different skin diseases. The proposed method is characterized by the accuracy of 96.31% on this dataset. It is improved accuracy in comparison with the existing neural network models. Software component model was created to give a possibility to integrate the proposed method into a medical diagnosis system. Conclusions. The obtained results of the investigation suggest application of the proposed skin disease method in medical diagnostic system to make advisory decisions by the system and to support making final decisions by a doctor.
Mie scattering computation of spherical particles with very large size parameters using an improved program with variable speed and accuracy

The electromagnetic radiation scattering patterns were computed using an improved C program to study variations in the patterns with changes in the size distribution, size parameters and refractive index of small particles in a volume element. The particle size distributions considered were gamma, normal and lognormal. The program is stable for computation of the theoretical values of the non-zero elements of the scattering matrix, efficiency factors, single scattering albedo, radiation pressure and asymmetry parameter for particles ranging from very small to very large size parameters. One of the significant features of the program is that it incorporates two methods for the determination of the optimal number of terms required for the computation of Mie series with the added benefit of having the option of either going for computational speed or accuracy. After a comparison of the C program with other reported benchmark results, it has been found that the program is very accurate and reliable for electromagnetic scattering computations.
Optimal Control of Damped Flexible Gyroscopic Systems

An optimal control scheme for damped gyroscopic systems is presented. The procedure works with real quantities alone. The optimal control scheme is based on the concept of independent modal-space control, leading to a set of independent second-order matrix Riccati equations. The solution of such equations can be obtained with relative ease for both the steady-state and the transient case. Damping is shown to be beneficial, resulting in enhanced control with less control effort.
Nonlinear Dynamics of Heart Rate Variability after Acutely Induced Myocardial Ischemia by Percutaneous Transluminal Coronary Angioplasty

Several heart rate variability (HRV) characteristics of patients with myocardial ischemia are associated with a higher mortality risk. However, the immediate effect of acute ischemia on the HRV nonlinear dynamical behavior is unknown. The objective of this work is to explore the presence of nonlinearity through surrogate data testing and describe the dynamical behavior of HRV in acutely induced ischemia by percutaneous transluminal coronary angioplasty (PTCA) with linear and recurrence quantification analysis (RQA). Short-term electrocardiographic recordings from 68 patients before and after being treated with elective PTCA were selected from a publicly available database. The presence of nonlinear behavior was confirmed by determinism and laminarity in a relevant proportion of HRV time series, in up to 29.4% during baseline conditions and 30.9% after PTCA without statistical difference between these scenarios. After PTCA, the mean value and standard deviation of HRV time series decreased, while determinism and laminarity values increased. Here, the diminishment in overall variability caused by PTCA is not accompanied by a change in nonlinearity detection. Therefore, the presence of nonlinear behavior in HRV time series is not necessarily in agreement with the change of traditional and RQA measures.