Constructive Analysis for Least Squares Regression with Generalized K

We introduce a constructive approach for the least squares algorithms with generalized K-norm regularization. Different from the previous studies, a stepping-stone function is constructed with some adjustable parameters in error decomposition. It makes the analysis flexible and may be extended to other algorithms. Based on projection technique for sample error and spectral theorem for integral operator in regularization error, we finally derive a learning rate

Perturbation of convex risk minimization and its application in differential private learning algorithms

Abstract Convex risk minimization is a commonly used setting in learning theory. In this paper, we firstly give a perturbation analysis for such algorithms, and then we apply this result to differential private learning algorithms. Our analysis needs the objective functions to be strongly convex. This leads to an extension of our previous analysis to the non-differentiable loss functions, when constructing differential private algorithms. Finally, an error analysis is then provided to show the selection for the parameters

Low-power, high-linearity transconductor with a high tolerance for process and temperature variations

Funding Information: This research was supported by the Major State Basic Research Development Programme of China (2018YFE0206500). Publisher Copyright: © The Institution of Engineering and Technology 2020. This is the peer reviewed version of the following article: Zhao, J., Sun, Y., Nie, G., Simpson, O. and Xu, W. (2020), Low‐power, high‐linearity transconductor with a high tolerance for process and temperature variations. IET Circuits Devices Syst., 14: 1295-1304. https://doi.org/10.1049/iet-cds.2019.0565. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.A novel scheme for tunable complementary metal–oxide–semiconductor (CMOS) transconductor robust against process and temperature (PT) variations is presented. The proposed configuration is a voltage controlled circuit based on a double negative channel-metal-oxide-semiconductor (NMOS) transistor differential pairs connected in parallel, which has low power and high linearity. The PT compensation is completed by two identical PT compensation bias voltage generators (PTCBVGs), which can guarantee the designed transconductor high tolerance for PT variations. A complete CMOS transconductor with PTCBVG has been designed and simulated using 0.18 μm technology. The effectiveness of PT compensation technique is proved. The simulation results of post-layout are commensurate with pre-layout. Post-layout simulation results show that when temperature changes from - 40 to 85°C for different process corners (TT, SS, SF, FS and FF), the transconductance varies from 91.8 to 123.6 μS, the temperature coefficient is <1090 ppm/°C, the total harmonic distortion is from - 78 to -72dB at 1 MHz for 0.2 V PP input signal, -3 dB bandwidth changes from 2.5 to 5 GHz, input-referred noise varies from 78.1 to 124.8 nV/sqartHz at 1 MHz and DC power is from 1.5 to 3.2 mW.Peer reviewe

Revised chronology of central Tibet uplift (Lunpola Basin)

International audienceKnowledge of the topographic evolution of the Tibetan Plateau is essential for understanding its construction and its influences on climate, environment, and biodiversity. Previous elevations estimated from stable isotope records from the Lunpola Basin in central Tibet, which indicate a high plateau since at least 35 Ma, are challenged by recent discoveries of low-elevation tropical fossils apparently deposited at 25.5 Ma. Here, we use magnetostratigraphic and radiochronologic dating to revise the chronology of elevation estimates from the Lunpola Basin. The updated ages reconcile previous results and indicate that the elevations of central Tibet were generally low (<2.3 km) at 39.5 Ma and high (3.5 to 4.5 km) at ~26 Ma. This supports the existence in the Eocene of low-elevation longitudinally oriented narrow regions until their uplift in the early Miocene, with potential implications for the growth mechanisms of the Tibetan Plateau, Asian atmospheric circulation, surface processes, and biotic evolution

Stacking transfer of wafer-scale graphene-based van der Waals superlattices

Abstract High-quality graphene-based van der Waals superlattices are crucial for investigating physical properties and developing functional devices. However, achieving homogeneous wafer-scale graphene-based superlattices with controlled twist angles is challenging. Here, we present a flat-to-flat transfer method for fabricating wafer-scale graphene and graphene-based superlattices. The aqueous solution between graphene and substrate is removed by a two-step spinning-assisted dehydration procedure with the optimal wetting angle. Proton-assisted treatment is further used to clean graphene surfaces and interfaces, which also decouples graphene and neutralizes the doping levels. Twist angles between different layers are accurately controlled by adjusting the macroscopic stacking angle through their wafer flats. Transferred films exhibit minimal defects, homogeneous morphology, and uniform electrical properties over wafer scale. Even at room temperature, robust quantum Hall effects are observed in graphene films with centimetre-scale linewidth. Our stacking transfer method can facilitate the fabrication of graphene-based van der Waals superlattices and accelerate functional device applications

Fabrication of Shaped Chitin Fibers by Gradient Regeneration Combined with a Physical Pressure Method

The exigency within the textile industry for molded fibers has become increasingly pronounced, owing to the coveted attributes inherent in planar fiber products, namely, their luxuriant tactile quality, ethereal weightiness, and avant-garde allure. In this investigation, we propose a pioneering methodology for the synthesis of planar chitin fibers, diverging from the conventional paradigm of spinneret design for fiber shaping. Analytical methodologies, encompassing Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and optical microscopy, were judiciously harnessed to unravel the intricacies of the fiber formation process. By subjecting chitin fibers to coagulation baths infused with phytic acid, a stratified dermal-core architecture was engendered, endowing the fibers with remarkable malleability under exogenic forces, thereby culminating in the homogeneous production of planar chitin fibers. Thorough scrutiny through optical microscopy and cross-sectional analysis substantiates the efficacy of this innovative approach. These revelations not only bestow invaluable insights into the fabrication of planar fibers but also broaden the horizons of potential chitin applications across multifarious domains