19 research outputs found
ELECTRAMed: a new pre-trained language representation model for biomedical NLP
The overwhelming amount of biomedical scientific texts calls for the
development of effective language models able to tackle a wide range of
biomedical natural language processing (NLP) tasks. The most recent dominant
approaches are domain-specific models, initialized with general-domain textual
data and then trained on a variety of scientific corpora. However, it has been
observed that for specialized domains in which large corpora exist, training a
model from scratch with just in-domain knowledge may yield better results.
Moreover, the increasing focus on the compute costs for pre-training recently
led to the design of more efficient architectures, such as ELECTRA. In this
paper, we propose a pre-trained domain-specific language model, called
ELECTRAMed, suited for the biomedical field. The novel approach inherits the
learning framework of the general-domain ELECTRA architecture, as well as its
computational advantages. Experiments performed on benchmark datasets for
several biomedical NLP tasks support the usefulness of ELECTRAMed, which sets
the novel state-of-the-art result on the BC5CDR corpus for named entity
recognition, and provides the best outcome in 2 over the 5 runs of the 7th
BioASQ-factoid Challange for the question answering task
Fault Detection and Diagnosis with Imbalanced and Noisy Data: A Hybrid Framework for Rotating Machinery
Fault diagnosis plays an essential role in reducing the maintenance costs of
rotating machinery manufacturing systems. In many real applications of fault
detection and diagnosis, data tend to be imbalanced, meaning that the number of
samples for some fault classes is much less than the normal data samples. At
the same time, in an industrial condition, accelerometers encounter high levels
of disruptive signals and the collected samples turn out to be heavily noisy.
As a consequence, many traditional Fault Detection and Diagnosis (FDD)
frameworks get poor classification performances when dealing with real-world
circumstances. Three main solutions have been proposed in the literature to
cope with this problem: (1) the implementation of generative algorithms to
increase the amount of under-represented input samples, (2) the employment of a
classifier being powerful to learn from imbalanced and noisy data, (3) the
development of an efficient data pre-processing including feature extraction
and data augmentation. This paper proposes a hybrid framework which uses the
three aforementioned components to achieve an effective signal-based FDD system
for imbalanced conditions. Specifically, it first extracts the fault features,
using Fourier and wavelet transforms to make full use of the signals. Then, it
employs Wasserstein Generative Adversarial Networks (WGAN) to generate
synthetic samples to populate the rare fault class and enhance the training
set. Moreover, to achieve a higher performance a novel combination of
Convolutional Long Short-term Memory (CLSTM) and Weighted Extreme Learning
Machine (WELM) is proposed. To verify the effectiveness of the developed
framework, different datasets settings on different imbalance severities and
noise degrees were used. The comparative results demonstrate that in different
scenarios GAN-CLSTM-ELM outperforms the other state-of-the-art FDD frameworks.Comment: 23 pages, 11 figure
A comparative study of nonlinear manifold learning methods for cancer microarray data classification
CoV-ABM: A stochastic discrete-event agent-based framework to simulate spatiotemporal dynamics of COVID-19
The paper develops a stochastic Agent-Based Model (ABM) mimicking the spread
of infectious diseases in geographical domains. The model is designed to
simulate the spatiotemporal spread of SARS-CoV2 disease, known as COVID-19. Our
SARS-CoV2-based ABM framework (CoV-ABM) simulates the spread at any
geographical scale, ranging from a village to a country and considers unique
characteristics of SARS-CoV2 viruses such as its persistence in the
environment. Therefore, unlike other simulators, CoV-ABM computes the density
of active viruses inside each location space to get the virus transmission
probability for each agent. It also uses the local census and health data to
create health and risk factor profiles for each individual. The proposed model
relies on a flexible timestamp scale to optimize the computational speed and
the level of detail. In our framework each agent represents a person
interacting with the surrounding space and other adjacent agents inside the
same space. Moreover, families stochastic daily tasks are formulated to get
tracked by the corresponding family members. The model also formulates the
possibility of meetings for each subset of friendships and relatives. The main
aim of the proposed framework is threefold: to illustrate the dynamics of
SARS-CoV diseases, to identify places which have a higher probability to become
infection hubs and to provide a decision-support system to design efficient
interventions in order to fight against pandemics. The framework employs SEIHRD
dynamics of viral diseases with different intervention scenarios. The paper
simulates the spread of COVID-19 in the State of Delaware, United States, with
near one million stochastic agents. The results achieved over a period of 15
weeks with a timestamp of 1 hour show which places become the hubs of
infection. The paper also illustrates how hospitals get overwhelmed as the
outbreak reaches its pick