334 research outputs found
Absolute height measurement of specular surfaces with modified active fringe reflection photogrammetry
Deflectometric methods have existed for more than a decade for slope measurement of specular freeform surfaces through utilization of the deformation of a sample pattern after reflection from a test surface. Usually, these approaches require two-directional fringe patterns to be projected on a LCD screen or ground glass and require slope integration, which leads to some complexity for the whole measuring process.
This paper proposes a new mathematical measurement model for measuring topography information of freeform specular surfaces, which integrates a virtual reference specular surface into the method of active fringe reflection delfectometry and presents a straight-forward relation between height and phase. This method only requires one direction of horizontal or vertical sinusoidal fringe patterns to be projected on a LCD screen, resulting in a significant reduction in capture time over established method. Assuming the whole system has been pre-calibrated, during the measurement process, the fringe patterns are captured separately via the virtual reference and detected freeform surfaces by a CCD camera. The reference phase can be solved according to spatial geometrical relation between LCD screen and CCD camera. The captured phases can be unwrapped with a heterodyne technique and optimum frequency selection method. Based on this calculated unwrapped-phase and that proposed mathematical model, absolute height of the inspected surface can be computed. Simulated and experimental results show that this methodology can conveniently calculate topography information for freeform and structured specular surfaces without integration and reconstruction processes
Asymptotically Normal and Efficient Estimation of Covariate-Adjusted Gaussian Graphical Model
A tuning-free procedure is proposed to estimate the covariate-adjusted Gaussian graphical model. For each finite subgraph, this estimator is asymptotically normal and efficient. As a consequence, a confidence interval can be obtained for each edge. The procedure enjoys easy implementation and efficient computation through parallel estimation on subgraphs or edges. We further apply the asymptotic normality result to perform support recovery through edge-wise adaptive thresholding. This support recovery procedure is called ANTAC, standing for Asymptotically Normal estimation with Thresholding after Adjusting Covariates. ANTAC outperforms other methodologies in the literature in a range of simulation studies. We apply ANTAC to identify gene-gene interactions using an eQTL dataset. Our result achieves better interpretability and accuracy in comparison with CAMPE
Inductive Logical Query Answering in Knowledge Graphs
Formulating and answering logical queries is a standard communication
interface for knowledge graphs (KGs). Alleviating the notorious incompleteness
of real-world KGs, neural methods achieved impressive results in link
prediction and complex query answering tasks by learning representations of
entities, relations, and queries. Still, most existing query answering methods
rely on transductive entity embeddings and cannot generalize to KGs containing
new entities without retraining the entity embeddings. In this work, we study
the inductive query answering task where inference is performed on a graph
containing new entities with queries over both seen and unseen entities. To
this end, we devise two mechanisms leveraging inductive node and relational
structure representations powered by graph neural networks (GNNs).
Experimentally, we show that inductive models are able to perform logical
reasoning at inference time over unseen nodes generalizing to graphs up to 500%
larger than training ones. Exploring the efficiency--effectiveness trade-off,
we find the inductive relational structure representation method generally
achieves higher performance, while the inductive node representation method is
able to answer complex queries in the inference-only regime without any
training on queries and scales to graphs of millions of nodes. Code is
available at https://github.com/DeepGraphLearning/InductiveQE.Comment: Accepted at NeurIPS 202
Norm-in-Norm Loss with Faster Convergence and Better Performance for Image Quality Assessment
Currently, most image quality assessment (IQA) models are supervised by the
MAE or MSE loss with empirically slow convergence. It is well-known that
normalization can facilitate fast convergence. Therefore, we explore
normalization in the design of loss functions for IQA. Specifically, we first
normalize the predicted quality scores and the corresponding subjective quality
scores. Then, the loss is defined based on the norm of the differences between
these normalized values. The resulting "Norm-in-Norm'' loss encourages the IQA
model to make linear predictions with respect to subjective quality scores.
After training, the least squares regression is applied to determine the linear
mapping from the predicted quality to the subjective quality. It is shown that
the new loss is closely connected with two common IQA performance criteria
(PLCC and RMSE). Through theoretical analysis, it is proved that the embedded
normalization makes the gradients of the loss function more stable and more
predictable, which is conducive to the faster convergence of the IQA model.
Furthermore, to experimentally verify the effectiveness of the proposed loss,
it is applied to solve a challenging problem: quality assessment of in-the-wild
images. Experiments on two relevant datasets (KonIQ-10k and CLIVE) show that,
compared to MAE or MSE loss, the new loss enables the IQA model to converge
about 10 times faster and the final model achieves better performance. The
proposed model also achieves state-of-the-art prediction performance on this
challenging problem. For reproducible scientific research, our code is publicly
available at https://github.com/lidq92/LinearityIQA.Comment: Accepted by ACM MM 2020, + supplemental material
QA-GNN: Reasoning with Language Models and Knowledge Graphs for Question Answering
The problem of answering questions using knowledge from pre-trained language
models (LMs) and knowledge graphs (KGs) presents two challenges: given a QA
context (question and answer choice), methods need to (i) identify relevant
knowledge from large KGs, and (ii) perform joint reasoning over the QA context
and KG. In this work, we propose a new model, QA-GNN, which addresses the above
challenges through two key innovations: (i) relevance scoring, where we use LMs
to estimate the importance of KG nodes relative to the given QA context, and
(ii) joint reasoning, where we connect the QA context and KG to form a joint
graph, and mutually update their representations through graph neural networks.
We evaluate our model on QA benchmarks in the commonsense (CommonsenseQA,
OpenBookQA) and biomedical (MedQA-USMLE) domains. QA-GNN outperforms existing
LM and LM+KG models, and exhibits capabilities to perform interpretable and
structured reasoning, e.g., correctly handling negation in questions.Comment: NAACL 2021. Code & data available at
https://github.com/michiyasunaga/qagn
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