171 research outputs found
Achieve the Minimum Width of Neural Networks for Universal Approximation
The universal approximation property (UAP) of neural networks is fundamental
for deep learning, and it is well known that wide neural networks are universal
approximators of continuous functions within both the norm and the
continuous/uniform norm. However, the exact minimum width, , for the
UAP has not been studied thoroughly. Recently, using a
decoder-memorizer-encoder scheme, \citet{Park2021Minimum} found that for both the -UAP of ReLU networks and the -UAP of
ReLU+STEP networks, where are the input and output dimensions,
respectively. In this paper, we consider neural networks with an arbitrary set
of activation functions. We prove that both -UAP and -UAP for functions
on compact domains share a universal lower bound of the minimal width; that is,
. In particular, the critical width, ,
for -UAP can be achieved by leaky-ReLU networks, provided that the input
or output dimension is larger than one. Our construction is based on the
approximation power of neural ordinary differential equations and the ability
to approximate flow maps by neural networks. The nonmonotone or discontinuous
activation functions case and the one-dimensional case are also discussed
Minimum Width of Leaky-ReLU Neural Networks for Uniform Universal Approximation
The study of universal approximation properties (UAP) for neural networks
(NN) has a long history. When the network width is unlimited, only a single
hidden layer is sufficient for UAP. In contrast, when the depth is unlimited,
the width for UAP needs to be not less than the critical width
, where and are the dimensions of the
input and output, respectively. Recently, \cite{cai2022achieve} shows that a
leaky-ReLU NN with this critical width can achieve UAP for functions on a
compact domain , \emph{i.e.,} the UAP for . This
paper examines a uniform UAP for the function class and
gives the exact minimum width of the leaky-ReLU NN as
, which involves the effects of the
output dimensions. To obtain this result, we propose a novel
lift-flow-discretization approach that shows that the uniform UAP has a deep
connection with topological theory.Comment: ICML2023 camera read
MFMAN-YOLO: A Method for Detecting Pole-like Obstacles in Complex Environment
In real-world traffic, there are various uncertainties and complexities in
road and weather conditions. To solve the problem that the feature information
of pole-like obstacles in complex environments is easily lost, resulting in low
detection accuracy and low real-time performance, a multi-scale hybrid
attention mechanism detection algorithm is proposed in this paper. First, the
optimal transport function Monge-Kantorovich (MK) is incorporated not only to
solve the problem of overlapping multiple prediction frames with optimal
matching but also the MK function can be regularized to prevent model
over-fitting; then, the features at different scales are up-sampled separately
according to the optimized efficient multi-scale feature pyramid. Finally, the
extraction of multi-scale feature space channel information is enhanced in
complex environments based on the hybrid attention mechanism, which suppresses
the irrelevant complex environment background information and focuses the
feature information of pole-like obstacles. Meanwhile, this paper conducts real
road test experiments in a variety of complex environments. The experimental
results show that the detection precision, recall, and average precision of the
method are 94.7%, 93.1%, and 97.4%, respectively, and the detection frame rate
is 400 f/s. This research method can detect pole-like obstacles in a complex
road environment in real time and accurately, which further promotes innovation
and progress in the field of automatic driving.Comment: 11 page
A Robotic Training System for Studies of Post-SCI Stand Rehabilitation
This paper describes a robotic training system designed to rehabilitate the standing ability of mice after spinal cord injury(SCI). The system is composed of a 6 Degree-of-Freedom (DOF) parallel mechanism, an active weight support system, and other measuring equipments which can monitor the response of the mouse. Preliminary experiments showed that the mouse could generate a certain degree of weight-support stand response during the training
Many-Body Chiral Edge Currents and Sliding Phases of Atomic Spin Waves in Momentum-Space Lattice
Collective excitations (spinwaves) of long-lived atomic hyperfine states can be synthesized into a Bose-Hubbard model in momentum space. We explore many-body ground states and dynamics of a two-leg momentum-space lattice formed by two coupled hyperfine states. Essential ingredients of this setting are a staggered artificial magnetic field engineered by lasers that couple the spinwave states, and a state-dependent long-range interaction, which is induced by laser-dressing a hyperfine state to a Rydberg state. The Rydberg dressed two-body interaction gives rise to a state-dependent blockade in momentum space, and can amplify staggered flux induced anti-chiral edge currents in the many-body ground state in the presence of magnetic flux. When the Rydberg dressing is applied to both hyperfine states, exotic sliding insulating and superfluid/supersolid phases emerge. Due to the Rydberg dressed long-range interaction, spinwaves slide along a leg of the momentum-space lattice without costing energy. Our study paves a route to the quantum simulation of topological phases and exotic dynamics with interacting spinwaves of atomic hyperfine states in momentum-space lattice. Introduction-Chiral edge states have played an important role in understanding quantum Hall effects [1-3] in solid state materials [4-6]. Ultracold atoms exposed to artificial gauge fields provide an ideal platform to simulate chiral edge currents in and out of equilibrium. This is driven by the ability to precisely control and in-situ monitor [7, 8] internal and external degrees of freedom, and atom-atom interactions [9]. Chiral dynamics [10-13] has been examined in the continuum space [14, 15], ladders [16-20], and optical lattices [21-28]. However, chiral states realized in the coordinate space require extremely low temperatures (typical in the order of a few kilo Hz) to protect the topological states from being destroyed by motional fluctuations [13]. Up to now, experimental observations of chiral phenomena in ultracold gases are largely at a single-particle level, due to unavoidable dis-sipations (e.g. spontaneous emission and heating) [9, 29-33], while the realization of many-body chiral edge currents in ultracold atoms is still elusive
Isolation and Characterization of 89K Pathogenicity Island-Positive ST-7 Strains of Streptococcus suis Serotype 2 from Healthy Pigs, Northeast China
Streptococcus suis is a swine pathogen which can also cause severe infection, such as meningitis, and streptococcal-like toxic shock syndrome (STSS), in humans. In China, most of the S. suis infections in humans were reported in the southern areas with warm and humid climates, but little attention had been paid to the northern areas. Data presented here showed that the virulent serotypes 1, 2, 7, and 9 of S. suis could be steadily isolated from the healthy pigs in the pig farms in all the three provinces of Northeast China. Notably, a majority of the serotype 2 isolates belonged to the 89K pathogenicity island-positive ST-7 clone that had historically caused the human STSS outbreaks in the Sichuan and Jiangsu provinces of China, although the human STSS case caused by S. suis had never been reported in northern areas of China. Data presented here indicated that the survey of S. suis should be expanded to or reinforced in the northern areas of China
DynaComm: Accelerating Distributed CNN Training between Edges and Clouds through Dynamic Communication Scheduling
To reduce uploading bandwidth and address privacy concerns, deep learning at
the network edge has been an emerging topic. Typically, edge devices
collaboratively train a shared model using real-time generated data through the
Parameter Server framework. Although all the edge devices can share the
computing workloads, the distributed training processes over edge networks are
still time-consuming due to the parameters and gradients transmission
procedures between parameter servers and edge devices. Focusing on accelerating
distributed Convolutional Neural Networks (CNNs) training at the network edge,
we present DynaComm, a novel scheduler that dynamically decomposes each
transmission procedure into several segments to achieve optimal layer-wise
communications and computations overlapping during run-time. Through
experiments, we verify that DynaComm manages to achieve optimal layer-wise
scheduling for all cases compared to competing strategies while the model
accuracy remains untouched.Comment: 16 pages, 12 figures. IEEE Journal on Selected Areas in
Communication
Effects of Assist-as-needed Robotic Training Paradigms on the Locomotor Recovery of Adult Spinal Mice
This paper introduces a new “assist-as needed”
(AAN) training paradigm for rehabilitation
of spinal cord injuries via robotic training devices. In
the pilot study reported in this paper, nine female
adult Swiss-Webster mice were divided into three
groups, each experiencing a different robotic training
control strategy: a fixed training trajectory (Fixed
Group, A), an AAN training method without inter-limb
coordination (Band Group, B), and an AAN
training method with bilateral hindlimb coordination
(Window Group, C). Fourteen days after complete
transection at the mid-thoracic level, the mice were
robotically trained to step in the presence of an
acutely administered serotonin agonist, quipazine, for
a period of six weeks. The mice that received AAN
training (Groups B and C) show higher levels of recovery
than Group A mice, as measured by the number,
consistency, and periodicity of steps realized during
testing sessions. Group C displays a higher incidence
of alternating stepping than Group B. These
results indicate that this training approach may be
more effective than fixed trajectory paradigms in promoting
robust post-injury stepping behavior. Furthermore,
the constraint of inter-limb coordination
appears to be an important contribution to successful
training. Presented in this paper are also some preliminary
results from a recent full-scale study that
complements the conclusions from this pilot study
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