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In video denoising, the adjacent frames often provide very useful information, but accurate alignment is needed before such information can be harnassed. In this work, we present a multi-alignment network, which generates multiple flow proposals followed by attention-based averaging. It serves to mimic the non-local mechanism, suppressing noise by averaging multiple observations. Our approach can be applied to various state-of-the-art models that are based on flow estimation. Experiments on a large-scale video dataset demonstrate that our method improves the denoising baseline model by 0.2dB, and further reduces the parameters by 47% with model distillation. Code is available at https://github.com/IndigoPurple/MANet., 5 pages, 5 figures

With the progress of the urbanisation process, the urban transportation system is extremely critical to the development of cities and the quality of life of the citizens. Among them, it is one of the most important tasks to judge traffic congestion by analysing the congestion factors. Recently, various traditional and machine-learning-based models have been introduced for predicting traffic congestion. However, these models are either poorly aggregated for massive congestion factors or fail to make accurate predictions for every precise location in large-scale space. To alleviate these problems, a novel end-to-end framework based on convolutional neural networks is proposed in this paper. With learning representations, the framework proposes a novel multimodal fusion module and a novel representation mapping module to achieve traffic congestion predictions on arbitrary query locations on a large-scale map, combined with various global reference information. The proposed framework achieves significant results and efficient inference on real-world large-scale datasets.

code of the experiment study

The author intends to provide you with a beautiful, elegant, user-friendly cookbook for mathematics in Snapshot Compressive Imaging (SCI). Currently, the cookbook is composed of introduction, conventional optimization, and deep equilibrium models. The latest releases are strongly recommended! For any other questions, suggestions, or comments, feel free to email the author., Comment: 15 pages

Real estate prices have a significant impact on individuals, families, businesses, and governments. The general objective of real estate price prediction is to identify and exploit socioeconomic patterns arising from real estate transactions over multiple aspects, ranging from the property itself to other contributing factors. However, price prediction is a challenging multidimensional problem that involves estimating many characteristics beyond the property itself. In this paper, we use multiple sources of data to evaluate the economic contribution of different socioeconomic characteristics such as surrounding amenities, traffic conditions and social emotions. Our experiments were conducted on 28,550 houses in Beijing, China and we rank each characteristic by its importance. Since the use of multi-source information improves the accuracy of predictions, the aforementioned characteristics can be an invaluable resource to assess the economic and social value of real estate. Code and data are available at: https://github.com/IndigoPurple/PATE, Comment: Accepted by IEEE DSAA 2022. 10 pages, 3 figures

To achieve point cloud denoising, traditional methods heavily rely on geometric priors, and most learning-based approaches suffer from outliers and loss of details. Recently, the gradient-based method was proposed to estimate the gradient fields from the noisy point clouds using neural networks, and refine the position of each point according to the estimated gradient. However, the predicted gradient could fluctuate, leading to perturbed and unstable solutions, as well as a long inference time. To address these issues, we develop the momentum gradient ascent method that leverages the information of previous iterations in determining the trajectories of the points, thus improving the stability of the solution and reducing the inference time. Experiments demonstrate that the proposed method outperforms state-of-the-art approaches with a variety of point clouds, noise types, and noise levels. Code is available at: https://github.com/IndigoPurple/MAG, Comment: 5 pages, 6 figures

Tubular turbines are widely used in low water head and tidal power development due to their straight flow path, simple structure, and wide efficient area. However, the severe vibration during actual operation greatly affects the safe operation of the tubular turbine. This study performs a numerical calculation of the tubular turbine, which meets the actual machine conditions considering the free surface and water gravity; compares and analyzes the flow characteristics and pressure fluctuation spectrum characteristics in the tubular turbine under different water heads; and verifies the comparison with the actual machine test results to explore the vibration characteristics and vibration mechanism of the tubular turbine. Research results show that a large pressure difference is observed between the top and bottom of the runner chamber, and the runner needs to experience large periodic pressure fluctuations during rotation due to the combined effect of hydrostatic pressure and hydrodynamic pressure. Under different water heads, obvious flow turbulence and high turbulent kinetic energy areas are observed in the runner and draft tube due to the influence of the shape of the blade wake vortex. The vibration in the tubular turbine is mainly concentrated in the runner and draft tube and influenced by the water gravity and the runner structure of the transverse cantilever beam. The amplitude of pressure fluctuation is the largest when the frequency inside the runner is the blade passing frequency at each water head, so the maximum vibration position is located at the runner. The research results serve as a guide for the design and operation of the horizontal tubular turbine.

code of the experiment study.

Along with advances in optical sensors is the common practice of building an imaging system with heterogeneous cameras. While high-resolution (HR) videos acquisition and analysis are benefited from hybrid sensors, the intrinsic characteristics of multiple cameras lead to an interesting motion transfer problem. Unfortunately, most of the existing methods provide no theoretical analysis and require intensive training data. In this paper, we propose an algorithm using time series analysis for motion transfer among multiple cameras. Specifically, we firstly identify seasonality in motion data and then build an addictive time series model to extract patterns that could be transferred across cameras. Our approach has a complete and clear mathematical formulation, thus being efficient and interpretable. Through quantitative evaluations on real-world data, we demonstrate the effectiveness of our method. Furthermore, our motion transfer algorithm could combine with and facilitate downstream tasks, e.g., enhancing pose estimation on LR videos with inherent patterns extracted from HR ones. Code is available at https://github.com/IndigoPurple/TSAMT., 9 pages, 7 figures

Terahertz time-domain spectroscopy (THz-TDS) is one of the main research platforms for terahertz (THz) science and technology. However, a traditional system is not only bulky but also has some limitations in detecting micro and liquid samples because of the large THz beam spot dimensions and the strong THz-wave absorption by water. We have developed a THz-TDS measurement chip by directly fabricating THz transmission lines and photoconductive antenna electrodes on a low-temperature GaAs epitaxial wafer. This chip integrates THz-waves generation device, detection device, and the transmission line in the size of 1 mm × 20 μm and uses the between the THz evanescent field sample interaction near the transmission line to obtain the spectral information from the trace or liquid samples. Using a self-built measurement beam path, we tested the chip with 1550-nm femtosecond laser and obtained THz spectroscopy in the 0.1 to 0.7 THz range, thereby verifying the feasibility of the chip.

Nitrogen and oxygen heteroatom doped porous carbon frameworks (HPCFs) have been constructed through the structural evolution of 2D microporous Schiff-base frameworks from the rigid polyquinoneimine and trigonal-symmetrical triformylphloroglucinol. Owing to its predictable and controllable nitrogen and oxygen doping and pore structures, the derived HPCF material exhibits good electrochemical properties as a supercapacitor electrode with remarkable specific capacitance (479.5 F g−1 at 0.1 A g−1 and 125 F g−1 at 10 A g−1) and excellent long-term cycling stability over 10 000 cycles. The combined effect of heteroatom doping and micropores on its electrochemical performance as a supercapacitor electrode is thoroughly investigated. According to the analysis of the electrochemical behavior, pores larger than 5 A in HPCFs are effective for electrical double-layer capacitance, which is associated with the size of hydrated ions. With regard to the heteroatoms, while the quaternary nitrogen functionalities can improve electron transfer, pyrrolic and pyridinic nitrogens as well as quinone oxygen are the most conducive functional groups for pseudocapacitive performance.

Terahertz on-chip system integrates the generation of terahertz, detection devices and transmission lines on the same substrate. It has the characteristics of small size, high measurement stability and easy operation. This paper is devoted to the study of the electrode of the photoconductive antenna necessary for the generation and detection of terahertz. HFSS software is used to simulate seven types of antennas with two types, large aperture and small aperture. The S11 images and VSWR images of each structure are obtained, and the emission efficiency of the optimal antenna electrode structure is obtained by comparison. For small aperture antenna, rectangular antenna has the highest transmitting efficiency; for large aperture antenna, dipole antenna and dish antenna have higher efficiency. But in the butterfly antenna, when the antenna spacing and the antenna length are both 50μm, the reflection power is the smallest and the performance is the best. These simulation results provide a parameter basis for the subsequent fabrication of chips.

The coplanar waveguide has relatively low radiation loss in the millimeter wave band. In this paper, we find the most suitable coplanar waveguide structure parameters for the transmission of terahertz (THz) using the software of Ansoft HFSS.

A design of microstrip line (MSL) has been used for propagating terahertz wave through an on-chip system. The ultimate aim of this article is to obtain the best parameters for the transmission of the THz wave in the MSL using HFSS simulation software.

We designed a compact diode-end-close-pumped passively Q-switched composite Nd:YAG/Cr4+:YAG laser. By a single F-mount packaged fast-collimated laser diode without any optical pump coupling components, we achieved a 1.7 ns pulse width output with an 11.4 kHz pulse repetition rate at a 2 W continuous wave pump power in the resonator formed by the coated end surfaces of the crystal, and this agrees with numerical simulations. The corresponding pulse energy and average output power is 21 μJ and 240 mW at 1,064 nm, and the beam is near-diffraction-limited with M2∼1.5. To the best of our knowledge, these are the highest pulse energy and average power in directly close-pumped passive lasers. The laser overall size without the forced air cooling system is smaller than a one-pound coin, and such miniaturization will lead to more widespread applications.

Background The aim of this study was to investigate the feasibility and value of strain-blood pressure index (SBPI) to assess early changes in elasticity of anterior tibial artery in patients with type 2 diabetes mellitus (T2DM). Material/Methods Eighty-one randomly selected in-patients with T2DM were divided into 2 groups – a vascular complication negative group (n=42) and a vascular complication positive group (n=39). Forty healthy volunteers were enrolled in a control group. Ultrasonographic scans using Xstrain™ technique were conducted for every patient to obtain the maximum circumferential strain (CSmax) of anterior tibial artery; patient blood pressure was also measured for calculating strain-blood pressure index (SBPI=CSmax/[(local pulse pressure)/local diastolic blood pressure] ×100%. Afterwards, SBPIs of various groups were comparatively analyzed. Results Differences in SBPIs among the 3 groups were statistically significant (control group > negative group > positive group, P

In the present paper, the tooth contact characteristics and the error sensitivity of the ease-off dual-torus double-enveloping hourglass worm drive (the DTT worm drive) are considered. The ease-off hourglass worm drive is composed of a standard hourglass worm and a modified worm wheel. In order to determine the instantaneous contact point of the mismatched worm pair, the two-stage downhill secant method (the TSDS method) is proposed to be used for solving the nonlinear contact equations. Roughly speaking, the main merits of the TSDS method are lower sensitivity to the initial guess, without a request for computing the Jacobi matrix and no singularity near the genuine solution. After ascertaining the transient contact point, the momentary contact ellipse, the instantaneous transmission ratio and some other tooth contact features are worked out by means of an improved local synthesis approach, which is proposed for point contact gear drives in this article. The results of computerized simulation show that, the mismatched worm gear set is able to accomplish desirable point contact, and has respectable load carrying capacity. On the other hand, the mismatched worm gearing is insensitive to the alignment errors, and its property of the transmission error is advantageous to reduce the noise and vibration.

In this paper, the theory of tooth flank modification is enriched and developed for a double-enveloping toroidal worm drive. The goal and significance of the modification are expounded from the point of view of changing the tooth flank configuration for the worm gear pair. It is pointed out that the constant center distance modification, the constant transmission ratio modification, and the combination of the previous two are the convenient and reasonable modification strategies. All the corrected hourglass worm pairs, attained by employing the preceding modification methodology, can be divided into two fundamental types: the type I worm pair and the type II worm pair, from the perspective of the meshing behavior. The division criterion of the worm drive type is moreover provided on the basis of the value range of the modification parameters in this study. The meshing characteristics of the two types of the modified globoidal worm drive are summarized in detail. The results indicate that the type II worm gearing with slight modification should be the preferred style for the double-enveloping toroidal worm drive.

The double-point downhill secant method (the DPDS method) is proposed to solve the nonlinear equations to determine the curvature interference limit points for modified hourglass worm drives. Thereupon, the whole curvature interference limit line can be obtained by interpolation. Based on this, the undercutting feature of the corrected worm gear can be investigated. The DPDS method has two main merits in principle. The first is the avoidance of the computation of the Jacobi matrix of the system of nonlinear equations. The second is that the sensitivity to the guess value can be decreased evidently owing to adopt the technique of the norm reduction. The effectiveness of the DPDS method is inspected and verified by a numerical example.

A universal modification theory is developed for all kinds of hourglass worm drives, no matter what shape the generating surface of the worm is. Based on the theory established, toroidal worm drives can be classified into two main categories: with singular points and without singular points. That is to say, the unmodified hourglass worm gearing is merely a special case of the modified one in essence. Furthermore, the meshing characteristics of a double-enveloping toroidal worm drive are entirely up to the situation of the solution of the meshing equation of the second envelope.

A flank modification methodology is proposed for the double-enveloping toroidal worm drive and a novel type of the dual-torus double-enveloping toroidal worm drive (the DTT worm drive) is developed. Because the height variation of the tool relative to the position during generating an unmodified worm is the unique modification parameter, this novel type of worm drive can be named as the height-modified DTT worm drive. Based on a strict meshing analysis, the selection principle of the modification style is recommended. A systematic and thorough study is conducted on the meshing behavior of the height-modified DTT worm pair by means of a computer simulation. The investigation results show that the height-modified DTT worm drive has favorable meshing performance.

A novel type of hourglass worm is considered, whose surface is formed by the locus of a circular blade. The worm has circular tooth profiles, which are relatively plain. According to the generation mechanism, the mathematical model for precisely manufacturing this kind of worm is developed, especially including the equation of the worm screw surface. A method to calculate the worm tooth profile is proposed. A numerical example is given to demonstrate the validity of the mathematical model and the proposed method.

A new type of toroidal worm gearing (the DTT worm drive) with concave worm profiles, ground by a grinding wheel whose two tori are symmetrical about its own mid-plane, is considered. The complete meshing theory of the DTT worm pair is established, especially including the computational method of the contact zone and the contact lines and the formulae of the induced principal curvature and the sliding angle. Furthermore, systematic researches are made on the meshing characteristics, such as the top thickness of the worm edge-tooth, the configurations of the worm helicoid and the mating wheel tooth flank and the curvature natures of the two conjugate surfaces. In addition, the effects of the technological parameters on the meshing behavior of a DTT worm set are studied in detail by means of computerized simulation approach. The obtained results demonstrate that the DTT worm pair offers advantageous meshing performance. Based on these results, the primary principles of selecting the technological parameters for processing the proposed worm set are recommended.

In this paper, the meshing theory of the angle modified hourglass worm drive is enriched and developed. The ordinary condition of the angle modification is derived and the physical significance of the modification is interpreted. A normal section methodology is proposed for meshing analysis, which can be used to compute the normal distance near a singular meshing point of a conjugate surface couple. By means of the method and after analyzing the normal transversals, it is specified that the worm helicoid, the nominal former contact zone and the new contact zone intersect each other along the locus of singular points of the instantaneous contact lines of an angle-modified worm pair. As a result, it is explained clearly that those three osculate each other but the osculations are different in degree. Moreover, the mechanism of removing the twice-contacted zone from the worm gear tooth surface is clarified and the reason of shortening the worm working length is also elucidated. With the help of the theory described in the present paper and the thorough and systematic research on the relevant meshing characteristics, the angle modified dual tori double-enveloping toroidal worm drive has been shown to be an excellent new-fashioned hourglass worm set.

Based on the theory of elastohydrodynamic lubrication (EHL), a mathematic model is developed and corresponding computer programs are proposed for calculating the EHL characteristic parameters of a novel type of toroidal worm drive, including the geometrical coefficient of minimum oil film thickness, the average entrainment velocity, the lubricating angle, the velocity ratio of sliding and rolling and so on, by using the theory of gearing. The numerical examples show the verification and validation of the principium and the model. The simulation investigation demonstrates that the dual tori double-enveloping toroidal worm drive has better lubricating property. In this foundation, the preliminary rules of selecting the design and technical parameters are proposed for this type of toroidal worm drive.

Thorough and systematic investigations are performed into the meshing principium of generating a cylindrical gear by an Archimedes hob based on the two-degree-of-freedom theory of gearing geometry. The numerical examples show the verification and validation of the formulated principium and the developed model. Conclusions suitable for industrial application are reached by means of numerical simulations.

In this paper, the 2DOF (two degree-of-freedom) theory of gearing presented in previous work [Xuezhu Dong, Study on the 2DOF gearing, Part I, Gear 14 (4) (1990) 1–7 (in Chinese)] is generalized. All-around and systematical researches are made on the generating tool surface configuration. Some new and practical expressions of the calculating vector are replenished. The formulae of the induced normal curvature and the induced geodesic-torsion become more compact and clearer. A rather general formula of the relative sliding ratio is proposed.

A novel photocatalyst, α-FeOOH-coated resin (α-FeOOHR), was prepared and applied for the photodegradation of natural estrogen 17β-estradiol (E2) in presence of H2O2 under the relatively weak UV irradiation. The continuing loading of ferric oxide on resin was achieved by in situ hydrolysis of Fe3+ in alkaline solution. The effects of initial pH, catalyst loading, oxidant concentration and iron leaching on the photodegradation of E2 were investigated. The batch photodegradation experiment showed that high removal efficiency of E2 and fairly good mechanic stability could be obtained by the spherical photocatalyst α-FeOOHR in aqueous solutions. The photodegradation efficiencies slightly decreased with the increase of initial pH in the wide pH range of 3–11. Increase of oxidant and catalyst will enhance photodegradation efficiencies thus lead to increase the Ferric leaching. Neglected iron leaching showed the stability of the loaded α-FeOOH withstanding the oxidation. X-ray photoelectron spectrum (XPS) shed light on the surface activity change of photocatalyst and heterogeneous catalytic essence of this process.

Heat-treatment i s emphasized for its important role to qualify the heavy rail. The temperature and stress field of U71Mn heavy rail during the quenching process were simulated by the FEM software and various kinds of factors that may influence temperature and stress field distribut ion were investigated . The result shows that the main factors influenc ing the temperature and stress field distribut ion were the heating and holding time, as well as the pressure of air blast during the coo l ing, whose values would directly influence the final performance of the heavy rail after the heat treatment. It is significantly valuable for the choice of relevant parameters for the heat treatment of U71Mn heavy rail.

The preparation of multipartite entangled states is the prerequisite for exploring quantum information networks and quantum computation. In this letter, we present the first experimental demonstration of eight-partite spatially separated CV entangled states. The initial resource quantum states are eight squeezed states of light, through the linearly optical transformation of which two types of the eight-partite cluster entangled states are prepared, respectively. The generated eight entangled photonic qumodes are spatially separated, which provide valuable quantum resources to implement more complicated quantum information task., Comment: 14 pages, 7 figures

ObjectiveTo compare the therapeutic effect of acupuncture for gastrointestinal neurosis with that of oral remedy.MethodsEighty cases were randomly divided into the following 2 groups. In the treatment group, acupuncture was given for one month at the main points of Zhongwan (CV 12), Zusanli (ST 36), Taichong (LR 3) and Shenmen (HT 7), with the auxiliary points selected according to TCM differentiation. In the control group, Domperidone was orally administered for one month.ResultsThe total effective rate was 92.5% in the treatment group and 75.0% in the control group, with a significant difference between the 2 groups (*chi;2=4.423, P < 0.05). Acupuncture was superior to the oral remedy in therapeutic effects.ConclusionsAcupuncture may show better results for gastrointestinal neurosis and with less toxic side effects.

A highly efficient nano-periodical grating is theoretically investigated for spectral beam combining (SBC) and is experimentally implemented for attaining high-brightness laser from a diode laser array. The rigorous coupled-wave analysis with the S matrix method is employed to optimize the parameters of the grating. According the optimized parameters, the grating is fabricated and plays a key role in SBC cavity. The diffraction efficiency of this grating is optimized to 95% for the output laser which is emitted from the diode laser array. The beam parameter product of 3.8 mm mrad of the diode laser array after SBC is achieved at the output power of 46.3 W. The optical-to-optical efficiency of SBC cavity is measured to be 93.5% at the maximum operating current in the experiment.

The three-dimensional numerical investigation for turbine-99 at the best efficiency operation point, part load operation point and full load operation point was conducted by using the different turbulence models. By comparing the results of numerical simulation and experimental results, it was found that: there is a certain deviation between the numerical simulation results obtained by different turbulence models and experimental values, and the deviation increase with the reduction of output. Compared to other turbulence model, the result obtained by the standard k-e turbulent model has a relatively small difference with the experimental results. The main causes for the big difference between the numerical simulation and model test include two aspects: (1) the mesh generation and boundary conditions setting lead to differences between the research object and the actual model, (2) it is difficult to accurately simulate the unstable flow such as impact, flow separation and vortex in the turbine. Therefore, in the future actual flow pattern simulation, besides the reasonable choice of turbulence model, based on the actual flow characteristics, the boundary conditions and the simulation results will be amended to reduce the deviation between the numerical simulation and experimental results as much as possible.