Construction of trivariate compactly supported biorthogonal box spline wavelets

AbstractWe give a formula for the duals of the masks associated with trivariate box spline functions. We show how to construct trivariate nonseparable compactly supported biorthogonal wavelets associated with box spline functions. The biorthogonal wavelets may have arbitrarily high regularities

Enhancing post-COVID-19 work resilience in hospitality: a micro-level crisis management framework

COVID-19 has led to immense impacts on the hospitality sector, putting millions of jobs at risk. The uncertainty has resulted in significant psychological effects on service staff. Developing on micro-level interpersonal interactions between line managers and service staff, this article aims to propose a bottom-up approach to alleviate service staff’s anxiety and enhance their work resilience during and after the pandemic. The proposed conceptual framework synthesised the personal uncertainty constructs, self-determination theory (SDT), and leader-member exchange (LMX) to address the psychological issues that emerged from a prolonged ambiguous and unsettled period. The framework proposes that interpersonal exchanges at the micro-level can strengthen service staff’s intrinsic motivation and resilience. This article offers new insights into crisis management research and practice in the hospitality sector by developing a people-centred approach. At the micro-level, this framework offers a holistic strategy, including a flat team structure, uncertainty-embracing organisational environment, transparent decision-making process, and sympathetic behaviours from leaders to facilitate service staff to develop greater coping mechanisms for the unknown future. Furthermore, this framework provides organisations preliminary guidelines to establish a longitudinal preventive strategy to strengthen employees’ work resilience

Research on Steady-State Characteristics of Centrifugal Pump Rotor System with Weak Nonlinear Stiffness

Steady-state vibration response characteristics of a motion model of a centrifugal pump rotor system with weak nonlinear stiffness have been calculated by using the multiple scale method (MSM). The theoretical results were in good agreement with the numerical results. Based on the MSM and the numerical method, the effects of detuning parameter, nonlinear stiffness parameter and natural frequency on steady-state amplitude were also investigated. Finally, Lyapunov\u27s theorem on stability in the first approximation was applied for the determination of the system’s stable and unstable solution regions. The calculated results imply that the centrifugal pump rotor system with weak nonlinear stiffness exhibits typical nonlinear vibration characteristics. The variation of detuning parameter, nonlinear stiffness parameter and natural frequency can result in a jump phenomenon, and their corresponding curves present ‘hard spring’, ‘soft spring’ and ‘S’-shaped amplitude characteristic, respectively. Smaller detuning parameter and natural frequency or greater nonlinear stiffness parameter are beneficial to decreasing the steady-state response amplitude. The results can provide reference for an investigation into nonlinear vibration characteristics of a centrifugal pump rotor system

Microstructure evolution and electrochemical properties of TiO 2 /Ti-35Nb-2Ta-3Zr micro/nano-composites fabricated by friction stir processing

Forming stable anti-corrosion surface layer and homogenized microstructure on the surface of material has become a major challenge in developing biomedical β titanium alloy. In the study, TiO 2 /Ti-35Nb-2Ta-3Zr anti-corrosion micro/nano-composites with different amount of TiO 2 particles were successfully fabricated by one-pass friction stir processing (FSP). The composition, microstructure and electrochemical properties of the material are characterized systematically. In particular, compact passive oxide films formed on surface of the material after electrochemical corrosion are elaborated from constituent, thickness and structural characteristics. Furthermore, the relationship between various FSP parameters, microstructure presented and corresponding corrosion resistance has been discussed in detail. The results show that TiO 2 /Ti-35Nb-2Ta-3Zr micro/nano-composite layers possess massive uniform β grains with homogeneous dispersive oxygen on the surface. Nanocrystallines surrounded by amorphous phases and α″ martensite accompanied with dislocations are discovered. TiO 2 /Ti-35Nb-2Ta-3Zr micro/nano-composite layers present outstanding corrosion resistance. More TiO 2 added and higher rotation speed promotes the optimization in corrosion resistance forming more compact passive films. The study displays the potential of a new micro/nano-composite with outstanding surface microstructure and corrosion resistance that serves better as a biomedical implant. © 2019 Elsevier Lt

GPU-based Private Information Retrieval for On-Device Machine Learning Inference

On-device machine learning (ML) inference can enable the use of private user data on user devices without revealing them to remote servers. However, a pure on-device solution to private ML inference is impractical for many applications that rely on embedding tables that are too large to be stored on-device. In particular, recommendation models typically use multiple embedding tables each on the order of 1-10 GBs of data, making them impractical to store on-device. To overcome this barrier, we propose the use of private information retrieval (PIR) to efficiently and privately retrieve embeddings from servers without sharing any private information. As off-the-shelf PIR algorithms are usually too computationally intensive to directly use for latency-sensitive inference tasks, we 1) propose novel GPU-based acceleration of PIR, and 2) co-design PIR with the downstream ML application to obtain further speedup. Our GPU acceleration strategy improves system throughput by more than $20 \times$ over an optimized CPU PIR implementation, and our PIR-ML co-design provides an over $5 \times$ additional throughput improvement at fixed model quality. Together, for various on-device ML applications such as recommendation and language modeling, our system on a single V100 GPU can serve up to $100,000$ queries per second -- a $>100 \times$ throughput improvement over a CPU-based baseline -- while maintaining model accuracy

Research progress of extracellular vesicles and exosomes derived from mesenchymal stem cells in the treatment of oxidative stress-related diseases

There is growing evidence that mesenchymal stem cell-derived extracellular vesicles and exosomes can significantly improve the curative effect of oxidative stress-related diseases. Mesenchymal stem cell extracellular vesicles and exosomes (MSC-EVs and MSC-Exos) are rich in bioactive molecules and have many biological regulatory functions. In this review, we describe how MSC-EVs and MSC-Exos reduce the related markers of oxidative stress and inflammation in various systemic diseases, and the molecular mechanism of MSC-EVs and MSC-Exos in treating apoptosis and vascular injury induced by oxidative stress. The results of a large number of experimental studies have shown that both local and systemic administration can effectively inhibit the oxidative stress response in diseases and promote the survival and regeneration of damaged parenchymal cells. The mRNA and miRNAs in MSC-EVs and MSC-Exos are the most important bioactive molecules in disease treatment, which can inhibit the apoptosis, necrosis and oxidative stress of lung, heart, kidney, liver, bone, skin and other cells, and promote their survive and regenerate

Efficient and bright warm-white electroluminescence from lead-free metal halides.

Solution-processed metal-halide perovskites are emerging as one of the most promising materials for displays, lighting and energy generation. Currently, the best-performing perovskite optoelectronic devices are based on lead halides and the lead toxicity severely restricts their practical applications. Moreover, efficient white electroluminescence from broadband-emission metal halides remains a challenge. Here we demonstrate efficient and bright lead-free LEDs based on cesium copper halides enabled by introducing an organic additive (Tween, polyethylene glycol sorbitan monooleate) into the precursor solutions. We find the additive can reduce the trap states, enhancing the photoluminescence quantum efficiency of the metal halide films, and increase the surface potential, facilitating the hole injection and transport in the LEDs. Consequently, we achieve warm-white LEDs reaching an external quantum efficiency of 3.1% and a luminance of 1570 cd m-2 at a low voltage of 5.4 V, showing great promise of lead-free metal halides for solution-processed white LED applications