435 research outputs found
Gazelle: A Low Latency Framework for Secure Neural Network Inference
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
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
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
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
A one-pot
multicomponent synthesis of a benzoÂ[<i>b</i>]Âphosphole 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
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
A one-pot
multicomponent synthesis of a benzoÂ[<i>b</i>]Âphosphole 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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