167 research outputs found
Contribution to Graph-based Manifold Learning with Application to Image Categorization.
122 pLos algoritmos de aprendizaje de variedades basados en grafos (Graph,based manifold) son técnicas que han demostrado ser potentes herramientas para la extracción de características y la reducción de la dimensionalidad en los campos de reconomiento de patrones, visión por computador y aprendizaje automático. Estos algoritmos utilizan información basada en las similitudes de pares de muestras y del grafo ponderado resultante para revelar la estructura geométrica intrínseca de la variedad
Contribution to Graph-based Manifold Learning with Application to Image Categorization.
122 pLos algoritmos de aprendizaje de variedades basados en grafos (Graph,based manifold) son técnicas que han demostrado ser potentes herramientas para la extracción de características y la reducción de la dimensionalidad en los campos de reconomiento de patrones, visión por computador y aprendizaje automático. Estos algoritmos utilizan información basada en las similitudes de pares de muestras y del grafo ponderado resultante para revelar la estructura geométrica intrínseca de la variedad
A multiple-time-step integration algorithm for particle-resolved simulation with physical collision time
In this paper, we present a multiple-time-step integration algorithm (MTSA)
for particle collisions in particle-resolved simulations. Since the time step
required for resolving a collision process is much smaller than that for a
fluid flow, the computational cost of the traditional soft-sphere model by
reducing the time step is quite high in particle-resolved simulations. In one
state-of-the-art methodology, collision time is stretched to several times the
flow solver time step for the fluid to adapt to the sudden change in particle
motion. However, the stretched collision time is not physical, the hydrodynamic
force may be severely underestimated during a stretched collision, and the
simulation of sediment transport may be sensitive to the stretched collision
time. The proposed MTSA adopts different time steps to resolve fluid flow,
fluid-particle interaction, and particle collision. We assessed the MTSA for
particle-wall collisions as well as particle-particle collisions, determined
the optimal iteration number in the algorithm, and obtained excellent
agreements with experimental measurements and reference simulations. The
computational cost of the MTSA can be reduced to about one order of magnitude
less than that using the traditional soft-sphere model with almost the same
accuracy. The MTSA was then implemented in a particle-resolved simulation of
sediment transport with thousands of particles. {By comparing the results
obtained using the MTSA and a version of the stretching collision time
algorithm similar to Costa et al.(2015), we found that stretching the collision
time reduced particle stiffness, weakened particle entrainment, and affected
some turbulence and particle statistics
A Diffusion Model for Event Skeleton Generation
Event skeleton generation, aiming to induce an event schema skeleton graph
with abstracted event nodes and their temporal relations from a set of event
instance graphs, is a critical step in the temporal complex event schema
induction task. Existing methods effectively address this task from a graph
generation perspective but suffer from noise-sensitive and error accumulation,
e.g., the inability to correct errors while generating schema. We, therefore,
propose a novel Diffusion Event Graph Model~(DEGM) to address these issues. Our
DEGM is the first workable diffusion model for event skeleton generation, where
the embedding and rounding techniques with a custom edge-based loss are
introduced to transform a discrete event graph into learnable latent
representation. Furthermore, we propose a denoising training process to
maintain the model's robustness. Consequently, DEGM derives the final schema,
where error correction is guaranteed by iteratively refining the latent
representation during the schema generation process. Experimental results on
three IED bombing datasets demonstrate that our DEGM achieves better results
than other state-of-the-art baselines. Our code and data are available at
https://github.com/zhufq00/EventSkeletonGeneration
A Generative Approach for Script Event Prediction via Contrastive Fine-tuning
Script event prediction aims to predict the subsequent event given the
context. This requires the capability to infer the correlations between events.
Recent works have attempted to improve event correlation reasoning by using
pretrained language models and incorporating external knowledge~(e.g.,
discourse relations). Though promising results have been achieved, some
challenges still remain. First, the pretrained language models adopted by
current works ignore event-level knowledge, resulting in an inability to
capture the correlations between events well. Second, modeling correlations
between events with discourse relations is limited because it can only capture
explicit correlations between events with discourse markers, and cannot capture
many implicit correlations. To this end, we propose a novel generative approach
for this task, in which a pretrained language model is fine-tuned with an
event-centric pretraining objective and predicts the next event within a
generative paradigm. Specifically, we first introduce a novel event-level blank
infilling strategy as the learning objective to inject event-level knowledge
into the pretrained language model, and then design a likelihood-based
contrastive loss for fine-tuning the generative model. Instead of using an
additional prediction layer, we perform prediction by using sequence
likelihoods generated by the generative model. Our approach models correlations
between events in a soft way without any external knowledge. The
likelihood-based prediction eliminates the need to use additional networks to
make predictions and is somewhat interpretable since it scores each word in the
event. Experimental results on the multi-choice narrative cloze~(MCNC) task
demonstrate that our approach achieves better results than other
state-of-the-art baselines. Our code will be available at
https://github.com/zhufq00/mcnc
Mutations associated with no durable clinical benefit to immune checkpoint blockade in Non-S-Cell lung cancer
(1) Background: The immune checkpoint blockade (ICB) has shown promising efficacy in non-small-cell lung cancer (NSCLC) patients with significant clinical benefits and durable responses, but the overall response rate to ICBs is only 20%. The lack of responsiveness to ICBs is currently a central problem in cancer immunotherapy. (2) Methods: Four public cohorts comprising 2986 patients with NSCLC were included in the study. We screened 158 patients with NSCLC with no durable clinical benefit (NDB) to ICBs in the Rizvi cohort and identified NDB-related gene mutations in these patients using univariate and multivariate Cox regression analyses. Programmed death-ligand 1 (PD-L1) expression, tumor mutation burden (TMB), neoantigen load, tumor-infiltrating lymphocytes, and immune-related gene expression were analyzed for identifying gene mutations. A comprehensive predictive classifier model was also built to evaluate the efficacy of ICB therapy. (3) Results: Mutations in FAT1 and KEAP1 were found to correlate with NDB in patients with NSCLC to ICBs; however, the analysis suggested that only mutation in FAT1 was valuable in predicting the efficacy of ICB therapy, and that mutation in KEAP1 acted as a prognostic but not a predictive biomarker for NSCLC. Mutations in FAT1 were associated with a higher TMB and lower multiple lymphocyte infiltration, including CD8 (T-Cell Surface Glycoprotein CD8)+ T cells. We established a prognostic model according to PD-L1 expression, TMB, smoking status, treatment regimen, treatment type, and FAT1 mutation, which indicated good accuracy by receiver operating characteristic (ROC) analysis (area under the curve (AUC) for 6-months survival: 0.763; AUC for 12-months survival: 0.871). (4) Conclusions: Mutation in FAT1 may be a predictive biomarker in patients with NSCLC who exhibit NDB to ICBs. We proposed an FAT1 mutation-based model for screening more suitable NSCLC patients to receive ICBs that may contribute to individualized immunotherapy.info:eu-repo/semantics/publishedVersio
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