1,075 research outputs found
A Semi-Supervised Two-Stage Approach to Learning from Noisy Labels
The recent success of deep neural networks is powered in part by large-scale
well-labeled training data. However, it is a daunting task to laboriously
annotate an ImageNet-like dateset. On the contrary, it is fairly convenient,
fast, and cheap to collect training images from the Web along with their noisy
labels. This signifies the need of alternative approaches to training deep
neural networks using such noisy labels. Existing methods tackling this problem
either try to identify and correct the wrong labels or reweigh the data terms
in the loss function according to the inferred noisy rates. Both strategies
inevitably incur errors for some of the data points. In this paper, we contend
that it is actually better to ignore the labels of some of the data points than
to keep them if the labels are incorrect, especially when the noisy rate is
high. After all, the wrong labels could mislead a neural network to a bad local
optimum. We suggest a two-stage framework for the learning from noisy labels.
In the first stage, we identify a small portion of images from the noisy
training set of which the labels are correct with a high probability. The noisy
labels of the other images are ignored. In the second stage, we train a deep
neural network in a semi-supervised manner. This framework effectively takes
advantage of the whole training set and yet only a portion of its labels that
are most likely correct. Experiments on three datasets verify the effectiveness
of our approach especially when the noisy rate is high
HetSeq: Distributed GPU Training on Heterogeneous Infrastructure
Modern deep learning systems like PyTorch and Tensorflow are able to train
enormous models with billions (or trillions) of parameters on a distributed
infrastructure. These systems require that the internal nodes have the same
memory capacity and compute performance. Unfortunately, most organizations,
especially universities, have a piecemeal approach to purchasing computer
systems resulting in a heterogeneous infrastructure, which cannot be used to
compute large models. The present work describes HetSeq, a software package
adapted from the popular PyTorch package that provides the capability to train
large neural network models on heterogeneous infrastructure. Experiments with
transformer translation and BERT language model shows that HetSeq scales over
heterogeneous systems. HetSeq can be easily extended to other models like image
classification. Package with supported document is publicly available at
https://github.com/yifding/hetseq.Comment: 7 pages, 3 tables, 2 figure
Multi-modal Domain Adaptation for REG via Relation Transfer
Domain adaptation, which aims to transfer knowledge between domains, has been
well studied in many areas such as image classification and object detection.
However, for multi-modal tasks, conventional approaches rely on large-scale
pre-training. But due to the difficulty of acquiring multi-modal data,
large-scale pre-training is often impractical. Therefore, domain adaptation,
which can efficiently utilize the knowledge from different datasets (domains),
is crucial for multi-modal tasks. In this paper, we focus on the Referring
Expression Grounding (REG) task, which is to localize an image region described
by a natural language expression. Specifically, we propose a novel approach to
effectively transfer multi-modal knowledge through a specially
relation-tailored approach for the REG problem. Our approach tackles the
multi-modal domain adaptation problem by simultaneously enriching inter-domain
relations and transferring relations between domains. Experiments show that our
proposed approach significantly improves the transferability of multi-modal
domains and enhances adaptation performance in the REG problem
CiGNN: A Causality-informed and Graph Neural Network Based Framework for Cuffless Continuous Blood Pressure Estimation:A Causality-informed and Graph Neural Network Based Framework for Cuffless Continuous Blood Pressure Estimation
Causality holds profound potentials to dissipate confusion and improve accuracy in cuffless continuous blood pressure (BP) estimation, an area often neglected in current research. In this study, we propose a two-stage framework, CiGNN, that seamlessly integrates causality and graph neural network (GNN) for cuffless continuous BP estimation. The first stage concentrates on the generation of a causal graph between BP and wearable features from the the perspective of causal inference, so as to identify features that are causally related to BP variations. This stage is pivotal for the identification of novel causal features from the causal graph beyond pulse transit time (PTT). We found these causal features empower better tracking in BP changes compared to PTT. For the second stage, a spatio-temporal GNN (STGNN) is utilized to learn from the causal graph obtained from the first stage. The STGNN can exploit both the spatial information within the causal graph and temporal information from beat-by-beat cardiac signals for refined cuffless continuous BP estimation. We evaluated the proposed method with three datasets that include 305 subjects (102 hypertensive patients) with age ranging from 20-90 and BP at different levels, with the continuous Finapres BP as references. The mean absolute difference (MAD) for estimated systolic blood pressure (SBP) and diastolic blood pressure (DBP) were 3.77 mmHg and 2.52 mmHg, respectively, which outperformed comparison methods. In all cases including subjects with different age groups, while doing various maneuvers that induces BP changes at different levels and with or without hypertension, the proposed CiGNN method demonstrates superior performance for cuffless continuous BP estimation. These findings suggest that the proposed CiGNN is a promising approach in elucidating the causal mechanisms of cuffless BP estimation and can substantially enhance the precision of BP measurement
A WRF-UCM-SOLWEIG framework of 10m resolution to quantify the intra-day impact of urban features on thermal comfort
City-scale outdoor thermal comfort diagnostics are essential for
understanding actual heat stress. However, previous research primarily focused
on the street scale. Here, we present the WRF-UCM-SOLWEIG framework to achieve
fine-grained thermal comfort mapping at the city scale. The background climate
condition affecting thermal comfort is simulated by the Weather Research and
Forecasting (WRF) model coupled with the urban canopy model (UCM) at a
local-scale (500m). The most dominant factor, mean radiant temperature, is
simulated using the Solar and Longwave Environmental Irradiance Geometry
(SOLWEIG) model at the micro-scale (10m). The Universal Thermal Climate Index
(UTCI) is calculated based on the mean radiant temperature and local climate
parameters. The influence of different ground surface materials, buildings, and
tree canopies is simulated in the SOLWEIG model using integrated urban
morphological data. We applied this proposed framework to the city of
Guangzhou, China, and investigated the intra-day variation in the impact of
urban morphology during a heat wave period. Through statistical analysis, we
found that the elevation in UTCI is primarily attributed to the increase in the
fraction of impervious surface (ISF) during daytime, with a maximum correlation
coefficient of 0.80. Tree canopy cover has a persistent cooling effect during
the day. Implementing 40% of tree cover can reduce the daytime UTCI by 1.5 to
2.0 K. At nighttime, all urban features have a negligible contribution to
outdoor thermal comfort. Overall, the established framework provides essential
input data and references for studies and urban planners in the practice of
urban (micro)climate diagnostics and planning
On Finding an Equivalent Force to Mimic the Multilayer Ceramic Capacitor Vibration
The Multilayer Ceramic Capacitor (MLCC) Can Vibrate Due to the Piezoelectric Effect When There is AC Noise on the Power Rail. the Vibration of the Capacitor Will Generate a Force on the PCB and Thus Cause the PCB Vibration and Audible Problems May Occur. the Work in This Paper Finds an Equivalent Force with Similar Behavior to the MLCC-Generated Force. the Force is Controllable and Knowable and Thus Can Mimic the Capacitor Vibration on the PCB
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