435 research outputs found

    Gazelle: A Low Latency Framework for Secure Neural Network Inference

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    The growing popularity of cloud-based machine learning raises a natural question about the privacy guarantees that can be provided in such a setting. Our work tackles this problem in the context where a client wishes to classify private images using a convolutional neural network (CNN) trained by a server. Our goal is to build efficient protocols whereby the client can acquire the classification result without revealing their input to the server, while guaranteeing the privacy of the server's neural network. To this end, we design Gazelle, a scalable and low-latency system for secure neural network inference, using an intricate combination of homomorphic encryption and traditional two-party computation techniques (such as garbled circuits). Gazelle makes three contributions. First, we design the Gazelle homomorphic encryption library which provides fast algorithms for basic homomorphic operations such as SIMD (single instruction multiple data) addition, SIMD multiplication and ciphertext permutation. Second, we implement the Gazelle homomorphic linear algebra kernels which map neural network layers to optimized homomorphic matrix-vector multiplication and convolution routines. Third, we design optimized encryption switching protocols which seamlessly convert between homomorphic and garbled circuit encodings to enable implementation of complete neural network inference. We evaluate our protocols on benchmark neural networks trained on the MNIST and CIFAR-10 datasets and show that Gazelle outperforms the best existing systems such as MiniONN (ACM CCS 2017) by 20 times and Chameleon (Crypto Eprint 2017/1164) by 30 times in online runtime. Similarly when compared with fully homomorphic approaches like CryptoNets (ICML 2016) we demonstrate three orders of magnitude faster online run-time

    Molecular Simulation of Electrolyte-Induced Interfacial Interaction between SDS/Graphene Assemblies

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    The interaction between surfactant-coated graphenes plays a critical role in the performance of surfactant-stabilized graphene dispersion. Herein, we quantified the interaction by simulating the potential of mean force (PMF) between two graphenes encapsulated in sodium dodecyl sulfate (SDS) surfactant micelles. It is observed that adsorbed SDS surfactants produce a long-range free energy barrier, hindering the aggregation of graphenes. Both increasing surfactant coverage and introducing electrolyte (CaCl<sub>2</sub>) can lead to an enhanced repulsive nature of PMF. Through splitting the total PMF into various contributions, the precise interaction mechanism of graphenes in aqueous SDS environment has been demonstrated. Furthermore, our result reveals the role of electrolyte ions in the modifying the interaction between the SDS/graphene assemblies, which cannot be accounted for by the traditional Derjaguin–Landau–Verwey–Overbeek (DLVO) theory. This result might show a possible microscopic evidence or explanation on the recently reported experiments. Additionally, a further analysis for SDS self-assembly morphology on graphene surface was used to explain the molecular origin of the electrolyte-induced structure transformation. The salt bridges formed between electrolyte cations and surfactants anions are confirmed to cause the structure change in the SDS/graphene assembly. This work provides a correlation analysis between the supramolecular self-assembly nanostructure and the interfacial interaction

    Mechanical Modeling of Particles with Active Core–Shell Structures for Lithium-Ion Battery Electrodes

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    Active particles with a core–shell structure exhibit superior physical, electrochemical, and mechanical properties over their single-component counterparts in lithium-ion battery electrodes. Modeling plays an important role in providing insights into the design and utilization of this structure. However, previous models typically assume a shell without electrochemical activity. Inaccurate interfacial conditions have been used to bridge the core and the shell in several studies. This work develops a physically rigorous model to describe the diffusion and stress inside the core–shell structure based on a generalized chemical potential. Including both chemical and mechanical effects, the generalized chemical potential governs the diffusion in both the shell and the core. The stress is calculated using the lithium concentration profile. Our simulations reveal a lithium concentration jump forming at the core–shell interface, which is only possible to capture by modeling the shell as electrochemically active. In sharp contrast to a single-component particle, a tensile radial stress develops at the core–shell interface during delithiation, while a tensile tangential stress develops in the shell during lithiation. We find that the core–shell interface is prone to debonding for particles with a thick shell, while shell fracture is more likely to occur for particles with a large core and a relatively thin shell. We show a design map of the core and shell sizes by considering both shell fracture and shell debonding

    Additional file 1 of Cost-effectiveness analysis of pembrolizumab versus chemotherapy as first-line treatment for mismatch-repair-deficient (dMMR) or microsatellite-instability-high (MSI-H) advanced or metastatic colorectal cancer from the perspective of the Chinese health-care system

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    Additional file 1: eTable 1. Summary of goodness of fit statistics for pembrolizumab – OS. eTable 2. Summary of goodness of fit statistics for pembrolizumab – PFS. eTable 3. Summary of goodness of fit statistics for chemotherapy – OS. eTable 4. Summary of goodness of fit statistics for chemotherapy – PFS. eFigure 1. Simulated survival curves (OS) for chemotherapy and pembrolizumab

    One-Pot Benzo[<i>b</i>]phosphole Synthesis through Sequential Alkyne Arylmagnesiation, Electrophilic Trapping, and Intramolecular Phospha-Friedel–Crafts Cyclization

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    A one-pot multicomponent synthesis of a benzo­[<i>b</i>]­phosphole derivative has been achieved by a sequence of transition-metal-catalyzed arylmagnesiation of an internal alkyne, electrophilic trapping of the resulting alkenylmagnesium species with a dichloroorganophosphine, and an intramolecular phospha-Friedel–Crafts reaction. With appropriate arylmagnesiation and P–C bond formation conditions, the present method allows for the modular and expedient preparation of benzophospholes bearing a variety of substituents on the phosphorus atom, the C2 and C3 atoms, and the “benzo” moiety

    Electrolyte-induced Reorganization of SDS Self-assembly on Graphene: A Molecular Simulation Study

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    A molecular dynamics simulation was conducted to study the structure and morphology of sodium dodecyl sulfate (SDS) surfactants adsorbed on a nanoscale graphene nanostructure in the presence of an electrolyte. The self-assembly structure can be reorganized by the electrolyte-induced effect. An increase in the ionic strength of the added electrolyte can enhance the stretching of adsorbed surfactants toward the bulk aqueous phase and make headgroups assemble densely, leading to a more compact structure of the SDS/graphene composite. The change in the self-assembly structure is attributed to the accumulation/condensation of electrolyte cations near the surfactant aggregate, consequently screening the electrostatic repulsion between charged headgroups. The role of the electrolyte revealed here provides direct microscopic evidence or an explanation of the reported experiments in the electrolyte tuning of the interfacial structure of a surfactant aggregate on the surface of carbon nanoparticles. Additionally, the buoyant density of the SDS/graphene assembly has been computed. With an increase in the ionic strength of the electrolyte, the buoyant density of the SDS/graphene composite rises. The interfacial accumulation of electrolytes provides an important contribution to the density enhancement. The study will be valuable for the dispersion and application of graphene nanomaterials

    One-Pot Benzo[<i>b</i>]phosphole Synthesis through Sequential Alkyne Arylmagnesiation, Electrophilic Trapping, and Intramolecular Phospha-Friedel–Crafts Cyclization

    No full text
    A one-pot multicomponent synthesis of a benzo­[<i>b</i>]­phosphole derivative has been achieved by a sequence of transition-metal-catalyzed arylmagnesiation of an internal alkyne, electrophilic trapping of the resulting alkenylmagnesium species with a dichloroorganophosphine, and an intramolecular phospha-Friedel–Crafts reaction. With appropriate arylmagnesiation and P–C bond formation conditions, the present method allows for the modular and expedient preparation of benzophospholes bearing a variety of substituents on the phosphorus atom, the C2 and C3 atoms, and the “benzo” moiety
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