Miracle-dz/UniFAR-FTUs huggingface dataset:
How to see 3-manifolds

There have been great strides made over the past 20 years in the understanding of three-dimensional topology, by translating topology into geometry. Even though a lot remains to be done, we already have an excellent working understanding of 3-manifolds. Our spatial imagination, aided by computers, is a critical tool, for the human mind is surprisingly well equipped with a bit of training and suggestion, to `see' the kinds of geometry that are needed for 3-manifold topology. This paper is not about the theory but instead about the phenomenology of 3-manifolds, addressing the question `What are 3-manifolds like? ' rather than `What facts can currently be proven about 3-manifolds? ' The best currently available experimental tool for exploring 3-manifolds is Jeff Weeks' program SnapPea. Experiments with SnapPea suggest that there may be an overall structure for the totality of 3-manifolds whose backbone is made of lattices contained in .
‘Safe Assets’ during COVID-19: A Portfolio Management Perspective

The pandemic crisis of COVID-19 hit the financial markets like a shockwave on 16 March 2020. This paper attempts to capture which ‘safe assets’ asset managers could have fled during the first wave of the pandemic. From an investment manager’s perspective, candidate assets are stocks, bonds, exchange rates, commodities, gold, and (gold-backed) cryptocurrencies. Empirical tests of the ‘Safe-Haven’ hypothesis are conducted, upon which the selection of assets is performed. The methodological framework hinges on the Global Minimum Variance Portfolio with Monte Carlo simulations, and the routine is performed under Python. Other optimization techniques, such as risk parity and equal weighting, are added for robustness checks. The benchmark portfolio hits a yearly profitability of 7.2% during such a stressful event (with 3.6% downside risk). The profitability can be enhanced to 8.4% (even 14.4% during sub-periods) with a careful selection of ‘Safe assets’. Besides short- to long-term U.S. bonds, we document that investors’ exposure to Chinese, Argentinian, and Mexican stocks during COVID-19 could have been complemented with Swiss and Japanese currencies, grains, physical gold mine ETFs, or gold-backed tokens for defensive purposes.
Impacts of the Decadal Urbanization on Thermally Induced Circulations in Eastern China

AbstractSignificant urbanization has occurred in the Yangtze River Delta region of eastern China, which exerts important effects on the local thermally induced circulations through regulating the heat flux and thermal structure. Previous studies lack a correct representation of the seasonal vegetation phenology associated with urban expansion, and therefore it is difficult to accurately describe the land–atmosphere coupling. In this study, high-resolution Moderate Resolution Imaging Spectroradiometer (MODIS) observations are used to describe the changes in land surface characteristics, including land-cover type, green vegetation fraction, and leaf area index with the Weather Research and Forecasting Model. The use of MODIS satellite observations provides a clear improvement in model performance when compared with ground-based measurements. A typical urban heat island is generated around Shanghai, Wuxi–Suzhou–Yangzhou, and cities along the Yangtze River and Hangzhou Bay, which subsequently modifies the loc.
Multi-valued resistive switching characteristics in WOx/AlOy heterojunction resistive switching memories

The multi-valued resistive switching (RS) characteristics and mechanism in a WOx/AlOy heterojunction-based nonvolatile memory have been investigated. Although Al/WOx/Pt and Al/AlOy/Pt show different RS characteristics, bipolar and unipolar modes, respectively, the Al/WOx/AlOy/Pt structure shows both bipolar and unipolar RS characteristics, depending on the magnitude of the applied voltage. Three resistance states, which are defined as the low-resistance state (LRS), the mid-high-resistance state (mid-HRS) and the high-resistance state (HRS), are observed. A model combining two different RS mechanisms, oxygen ions involving the redox process at the interface and filamentary conduction, is proposed, and provides a simple physical concept to understand the multi-valued RS behavior. Our findings will be useful to design and optimize oxide heterojunction-based non-volatile RS memory devices.
A New Oxide Spin Glass System of (1-x) FeTiO3–xFe2O3. II. Neutron Scattering Studies of a Cluster Type Spin Glass of 90FeTiO3–10Fe2O3

The spin correlations in a cluster type spin glass of 90FeTiO 3 –10Fe 2 O 3 have been studied by neutron small and high angle scattering from a single crystal. The magnetic correlations of the moments parallel and perpendicular to the c axis, and have been separately determined and the spin configuration inside the cluster as well as the cluster configuration have been determined. The spin glass transition temperature has been found to correspond to the temperature where the spin axis inside the cluster aligns in the c axis and the antiferromagnetic modulation starts to occur inside the cluster.
A Parallel Oversampling Algorithm Based on NRSBoundary-SMOTE

Classification with imbalanced class distribution data set has always been regarded as a difficult problem in knowledge discovery, and re-sampling is an effective way to deal with imbalanced data set. SMOTE is a widely used over-sampling algorithm, however it does not consider the distribution of the original data while generates new synthetic samples. NRSBoundary-SMOTE is based on Neighborhood RoughSet Theory. It only chooses the minority class samples, which belong to the boundary region, to generate synthetic samples, and it can improve the accuracy of the minority class effectively. But it needs to compute the distance of any two samples when parting the data set. That process will take a long time on large data sets. So we propose a parallel over-sampling method based on NRSBoundary-SMOTE, Parallel-NRSBoundary-SMOTE. And we apply our method by mapreduce programming paradigm. The experimental results that running on hadoop clusters shows that our method can maintain the accuracy of minority class and improve the efficiency on large data sets.
A cascade switching superconducting single photon detector

We have realized superconducting single photon detectors with reduced inductance and increased signal pulse amplitude. The detectors are based on a parallel connection of ultrathin NbN nanowires with a common bias inductance. When properly biased, an absorbed photon induces a cascade switch of all the parallel wires generating a signal pulse amplitude of 2mV. The parallel wire configuration lowers the detector inductance and reduces the response time well below 1ns.
Bubble Dynamics and Cavitation

The first analysis of a problem in cavitation and bubble dynamics was made by Rayleigh (1917), who solved the problem of the collapse of an empty cavity in a large mass of liquid. Rayleigh also considered in this same paper the problem of a gas-filled cavity under the assumption that the gas undergoes isothermal com­ pression. His interest in these problems presumably arose from concern with cavitation and cavitation damage. With neglect of surface tension and liquid viscosity and with the assumption of liquid incompressibility, Rayleigh showed from the momentum equation that the bubble boundary R(t) obeyed the relation RR+W<)2 = p(R)oo, p (1.1)
An Improved Digitizing Interface Circuit for Wide-Range Current-Output Sensors

A current digitizer, suitable for interfacing with a wide-range current-output sensor (COS) is proposed. The circuit features a transimpedance amplifier with a programmable-gain attenuating amplifier in its feedback which mimics the high-valued resistance required for a wide-range low-current to voltage conversion. The proposed scheme offers a fast response and is immune to switch resistances in the feedback circuit. This low-cost circuit uses a unipolar analog to digital converter (ADC) to sense bidirectional currents with reduced ADC quantization noise and offset error. A mathematical model of the scheme with error analysis is presented. The performance of the digitizing interface was established using simulations as well as experiments on a hardware prototype. The results show that the developed interface works well over the current range of 500 pA to $5 ~\mu \text{A}$ (dynamic range of 104) with nonlinearity (N. L.) less than 1.2%.
A Green function approach to surface optics in anisotropic media

A formalism based on dyadic Green functions is applied to the reflection and transmission of fields generated in the presence of anisotropic media. Our approach is general and treats the fields immediately in terms of s- and p-polarized components. Hence, the Fresnel reflection and transmission coefficients appear naturally in our expressions. The asymptotic far-field expansions of the dyadic Green functions are easily obtained, and numerical calculations in experimental geometries are straightforward.
Characterizing Internet Card User Portraits for Efficient Churn Prediction Model Design

Cellular Internet card (IC) as a new business model emerges, which penetrates rapidly and holds the potential to foster a great business market. However, with the explosive growth of IC users, the user churn problem becomes severe, affecting the IC business significantly, while there is lacking appropriate techniques in the literature to deal with the issue. In this article, we take the lead to study one large-scale data set from a provincial network operator of China, which contains about 4 million IC users and 22 million traditional card (TC) users. We first justify the IC user churn issue with data, and categorize the user churning reasons. Then, we shed light on understanding user portraits, which is the building block to enable efficient model design. Particularly, we conduct a systematical analytics on usage data by studying the difference of two types of users, examining the impact of user properties, and characterizing the user Internet using behaviors. Finally, by using the IC user portraits and usage patterns, we propose an IC user Churn Prediction model, named ICCP, which consists of a feature extraction component and a learning-based churn prediction architecture design. For feature extraction, both the static portrait features and temporal sequential features are captured. In the learning architecture, we devise the principal component analysis (PCA) block and the embedding/transformer layers to learn the respective information of two types of features, which are collectively fed into the classification multilayer perceptron layer (MPL) for churn prediction. A reference implementation of ICCP is conducted within the telecom system and extensive experiments corroborate the efficiency of ICCP.
Phase stability and structural temperature dependence in powdered multiferroic BiFeO 3

We report a temperature-dependent investigation of the multiferroic perovskite bismuth ferrite ${\text{BiFeO}}_{3}$ (BFO) by using x-ray powder diffraction together with differential scanning calorimetry measurements. Our results provide evidence that the paraelectric phase above ${T}_{c}=820\text{ }\ifmmode^\circ\else\textdegree\fi{}\text{C}$ is not cubic but distorted and can be well refined in a monoclinic $P{2}_{1}/m$ space group. An equivalent structure can be reconstructed based on the $C2/m$ monoclinic space group and by assuming two types of bismuth sites. The marked change of the cell volume at ${T}_{c}$ provides evidence for the first-order nature of the $R3c$-to-$P{2}_{1}/m$ transition. The high-temperature $P{2}_{1}/m$ phase is centrosymmetric and characterized by (i) strong oxygen octahedra tilting along the $b$ axis; (ii) the occurrence of antiferroelectric displacements of the Fe cations; and (iii) an interesting lamellar structure characterized by two different types of ${\text{BiO}}_{12}$ cages. The temperature-induced lamellar structure suggests a significant electronic rearrangement in terms of chemical bonding, which in turn might condition anisotropic electronic properties. The occurrence of a lamellar structure provides also an understanding of why BFO decomposes suddenly at higher temperatures. Finally, an anomaly in the evolution of the cell parameters at ${T}_{N}$ underlines the spin-lattice coupling in proximity of the magnetic transition.
Synthesis and characterisation of new antimalarial fluorinated triazolopyrazine compounds

Nine new fluorinated analogues were synthesised by late-stage functionalisation using Diversinate™ chemistry on the Open Source Malaria (OSM) triazolopyrazine scaffold (Series 4). The structures of all analogues were fully characterised by NMR, UV and MS data analysis; three triazolopyrazines were confirmed by X-ray crystal structure analysis. The inhibitory activity of all compounds against the growth of the malaria parasite Plasmodium falciparum (3D7 and Dd2 strains) and the cytotoxicity against a human embryonic kidney (HEK293) cell line were tested. Some of the compounds demonstrated moderate antimalarial activity with IC50 values ranging from 0.2 to >80 µM; none of the compounds displayed any cytotoxicity against HEK293 cells at 80 µM. Antimalarial activity was significantly reduced when C-8 of the triazolopyrazine scaffold was substituted with CF3 and CF2H moieties, whereas incorporation of a CF2Me group at the same position completely abolished antiplasmodial effects.
Losslessness, feedback equivalence, and the global stabilization of discrete-time nonlinear systems

In this paper a necessary and sufficient condition for a nonlinear system of the form /spl Sigma/, given by x(k+1)=f(x(k))+g(x(k))u(k), y(k)=h(x(k))+J(x(k))u(k), to be lossless is given, and it is shown that a lossless system can be globally asymptotically stabilized by output feedback if and only if the system is zero-state observable. Then, we investigate conditions under which /spl Sigma/ can be rendered lossless via smooth state feedback. In particular, we show that this is possible if and only if the system in question has relative degree /spl lcub/0,. ,0/spl rcub/ and has lossless zero dynamics. Under suitable controllability-like rank conditions, we prove that nonlinear systems having relative degree /spl lcub/0,. ,0/spl rcub/ and lossless zero dynamics can be globally stabilized by smooth state feedback. As a consequence, we obtain sufficient conditions for a class of cascaded systems to be globally stabilizable. The global stabilization problem of the nonlinear system /spl Sigma/ without output is also investigated in this paper by means of feedback equivalence. Some of the results are parallel to analogous ones in continuous-time, but in many respects the theory is substantially different and many new phenomena appear. >
Comparison the efficacy of amiodarone and lidocaine for cardiac arrest: A network meta-analysis

Background: There is no evidence that antiarrhythmic drugs can improve long-term survival or survival with favorable neurological outcomes in cardiac arrest patients. We did this network meta-analysis to comprehensively compare the efficacy of various antiarrhythmic drugs for cardiac arrest patients. Methods: We searched studies from inception until Nov 11, 2022 through PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), VIP Database, and Wanfang database. All studies comparing different antiarrhythmic drugs for cardiac arrest were included in this meta-analysis. Outcomes were survival to hospital discharge in cardiac arrest, survival to hospital admission/24 h and favorable neurological outcome. This network meta-analysis was performed by R software. Results: Finally, a total of 9 studies (10,980 patients) were finally included in this network meta-analysis. Amiodarone (odd ratio [OR] 2.28, 95% credibility interval [CrI] 1.61–3.27) and lidocaine (OR 1.53, 95% CrI 1.05–2.25) was superior than placebo in terms of the survival to hospital admission/24 h with statistically significant. Amiodarone (OR 2.19, 95% CrI 1.54–3.14) and lidocaine (OR 1.58, 95% CrI 1.09–2.32) was superior than placebo in terms of the survival to hospital discharge with statistically significant. Amiodarone (OR 2.43, 95% CrI 1.61–3.68) and lidocaine (OR 1.62, 95% CrI 1.04–2.53) was superior than placebo in terms of the favorable neurological outcome with statistically significant. The surface under the cumulative ranking (SUCRA) shows that amiodarone ranked first (SUCRA, 99.6%), lidocaine ranked second (SUCRA, 49.6%), placebo ranked the last (SUCRA, 0.86%). Inverted funnel plot is essentially symmetrical, it is possible that this study has a small sample effect or a small publication bias. Conclusions: Amiodarone had the best effect on both survival to hospital admission, discharge and more favorable neurological outcome. Thus, amiodarone should be listed as first line drug for cardiac arrest. However, the quality of available evidence limits the formation of powerful conclusions regarding the comparative efficacy or safety of amiodarone or lidocaine used to treat cardiac arrest. Higher-quality randomized controlled trials are required for further research in future.
A Generic Multi-Frequency Repetitive Control Scheme for Power Converters

A generic multifrequency repetitive control (GMFRC) scheme, is proposed to perfectly compensate for all kinds of periodic signals including multifrequency signals, where multiple selective harmonic repetitive controllers in parallel are added into a stable instantaneous feedback control loop to achieve overall satisfactory performance. The GMFRC scheme provides a general framework for housing various repetitive control and even resonant control schemes in power electronic conversion and other extensive engineering applications. A universal approach to the analysis and synthesis of the digital GMFRC scheme has been developed, which includes the stability criteria and control gain rules. More important, the digital GMFRC controller is transformed into a general fractional-order one for exact compensation of multifrequency signals and other fractional-order periodic signals in practice. An application example of a 5 kVA three-phase pulsewidth modulation nverter under a fractional-order GMFRC scheme is provided. Experimental results demonstrated that the proposed GMFRC scheme can force the inverter to produce required mono-frequency or multifrequency voltages with high accuracy, fast response and good robustness.
On Bose-Fermi Equivalence in a U(1) Gauge Theory with Chern-Simons Action

We show, using path integral methods, that a complex scalar field in 2+1 dimensions coupled to an abelian gauge field with Chern-Simons action is equivalent to a free Dirac fermion. We show the equivalence of the vacuum functional and construct the fermion fields explicitly. Our proof is independent of the long wavelength approximation.
Circle Actions and Higher Elliptic Genera

For a manifold with an S -action, we define generalized elliptic genera by using the orbit map and generalize Hirzebruch-Slodowy's formula in [9]. As a result, we have vanishing theorems of higher elliptic genera and higher twisted A-genera. We also generalize elliptic genera of level N for stable almost complex manifolds and have a similar vanishing theorem.
Multiplier IQC's for uncertain time-delays

This paper describes a set of delay-dependent integral quadratic constraints (IQC) for time-delay uncertainty. The set is linearly parameterized in terms of the frequency-response of a complex-valued multiplier. Using LMI optimization techniques, one may compute optimal multipliers and thereby obtain less conservative IQC stability robustness bounds for systems with uncertain time-delays.
Shielding Graph for eXact Analytics With SGX

Graphs nicely capture data from various domains, allowing the computations of many analytic tasks via graph queries. Graphs of real-world data are often large, albeit useful, and the involved computation can be too heavyweight for commodity computers. For secure outsourcing, we propose (SGX)<inline-formula><tex-math notation="LaTeX">$^{2}$</tex-math><alternatives><mml:math><mml:msup><mml:mrow/><mml:mn>2</mml:mn></mml:msup></mml:math><inline-graphic xlink:href="wang-ieq1-3241164.gif"/></alternatives></inline-formula>, a forward-secure structured encryption scheme for graph data, which uses lightweight cryptographic techniques with a trusted execution environment such as SGX. To process million-scale graphs by the limited memory of SGX, we load data on-demand using Dijkstra's algorithm and Fibonacci heap. Compared with most prior graph encryption schemes, (SGX)<inline-formula><tex-math notation="LaTeX">$^{2}$</tex-math><alternatives><mml:math><mml:msup><mml:mrow/><mml:mn>2</mml:mn></mml:msup></mml:math><inline-graphic xlink:href="wang-ieq2-3241164.gif"/></alternatives></inline-formula> supports exact shortest-distance queries instead of approximation and can be easily extended to other graph-based analytics.
University of Birmingham X-ray diffraction studies of charge density waves in cuprate superconductors: A brief review

High temperature superconductivity in the cuprates has fascinated scientists for more than 25 years, but there is still no consensus on the pairing mechanism. Soon after the discovery of high temperature superconductivity, it was suggested that the cuprates have an incipient tendency towards spatial electronic order spin and charge order. In this article, I will review X-ray diffraction studies of charge density waves in the cuprates. These results, by a number of different groups, indicate that short-range charge correlations exist across the cuprate family, and in many cases are clearly competing with the superconductivity.
Road surface and inventory extraction from mobile LiDAR point cloud using iterative piecewise linear model

Roads are one of the main characteristics of cities, and their data should be updated periodically. In this study, a new automatic method is proposed for extracting road surface information and road inventory from a Mobile LiDAR System-based point cloud. The proposed method consists of four steps. First, a three-dimensional point cloud is acquired using the mobile LiDAR scanning raw data. To improve the extraction accuracy, irrelevant points are removed from the point cloud. Piecewise linear models are used in the third step to classify the road surface. Road geometric characteristics such as centerline, profile, cross-section, and cross slope are extracted in the final step. The manually obtained road boundary is compared with the extracted road boundary to assess the classification results. Completeness, correctness, quality, and accuracy measures are range from 97% to 99% . When comparing these measures with previous studies, the proposed method produces one of the highest ones.
Low temperature dielectric dispersion and relaxor like behavior in multiferroic Ba3NbFe3Si2O14

The structure and physical properties such as magnetization, heat capacity, and dielectric constant of the polycrystalline Ba3NbFe3Si2O14 have been studied in detail. It is found to be structurally similar to the single crystal and also has a similar antiferromagnetic transition at TN∼26 K. The heat capacity measured in the temperature range 5 K–300 K also shows a single peak at 26 K in agreement with the magnetic behavior. The dielectric constant measured both as a function of temperature and frequency, 10 Hz to 1 MHz however exhibits two clear peaks in the temperature ranges, 20 K–35 K, and 40 K–125 K, which are dispersive in nature. Both the peaks are found to be coupled to the magnetic order with the high temperature peak signaling the onset of magnetic order while the low temperature peak signifies the completion of magnetic order. The dispersion behavior is similar to that observed in relaxor ferroelectrics wherein formation of polar nano-regions affects the relaxation dynamics.