分类： 计算机科学 >> 计算机科学的集成理论 提交时间： 2022-11-28 合作期刊: 《数据智能（英文）》
摘要： Few-shot learning has been proposed and rapidly emerging as a viable means for completing various tasks. Many few-shot models have been widely used for relation learning tasks. However, each of these models has a shortage of capturing a certain aspect of semantic features, for example, CNN on long-range dependencies part, Transformer on local features. It is difficult for a single model to adapt to various relation learning, which results in a high variance problem. Ensemble strategy could be competitive in improving the accuracy of few-shot relation extraction and mitigating high variance risks. This paper explores an ensemble approach to reduce the variance and introduces fine-tuning and feature attention strategies to calibrate relation-level features. Results on several few-shot relation learning tasks show that our model significantly outperforms the previous state-of-the-art models.
分类： 生物学 >> 生物物理学 >> 神经科学 提交时间： 2016-05-12
摘要： The human LGN and SC consist of distinct layers, but their layer-specific response properties remain poorly understood. In this fMRI study, we characterized visual response properties of the magnocellular (M) and parvocellular (P) layers of the human LGN, as well as at different depths in the SC. Results show that fMRI is capable of resolving layer-specific signals from the LGN and SC. Compared to the P layers of the LGN, the M layers preferred higher temporal frequency, lower spatial frequency stimuli, and their responses saturated at lower contrast. Furthermore, the M layers are colorblind while the P layers showed robust response to both chromatic and achromatic stimuli. Visual responses in the SC were strongest in the superficial voxels, which showed similar spatiotemporal and contrast response properties as the M layers of the LGN, but were sensitive to color and responded strongly to isoluminant color stimulus. Thus, the non-invasive fMRI measures show that the M and P layers of human LGN have similar response properties as that observed in non-human primates and the superficial layers of the human SC prefer transient inputs but are not colorblind. (C) 2015 Elsevier Inc. All rights reserved.
分类： 生物学 >> 生物物理学 提交时间： 2016-05-12
Wen, Wen
Liu, Tingting
Zhang, Ting
Sun, Xinghuai
Wen, Wen
Sun, Xinghuai
Wen, Wen
Sun, Xinghuai
Zhang, Peng
He, Sheng
Gao, Jian
Sun, Xinghuai
He, Sheng
摘要： PURPOSE. This study investigated a novel motion-on-color paradigm to functionally isolate the magnocellular pathway and evaluate its diagnostic value in preperimetric glaucoma patients. METHODS. Thirty patients with preperimetric primary open-angle glaucoma and 30 controls participated in this study. They were tested in both the foveal and peripheral locations. Contrast sensitivity was assessed for the direction discrimination of a moving luminance-modulated grating presented on top of a red/green isoluminant grating. The moving test grating was designed to target the magnocellular pathway, while the background red/green isoluminant grating was designed to saturate the parvocellular pathway. The luminance-modulated grating was presented at spatial frequency of 0.5 cyc/deg, moving horizontally at four temporal frequencies (3 Hz, 8 Hz, 15 Hz, 25 Hz). Participants were asked to indicate the direction of motion for the luminance grating. As a comparison condition, frequency-doubling stimuli were also presented in the periphery and participants were asked to detect the occurrence of the frequency-doubled pattern. Two-way repeated-measures analysis of variance was performed with temporal frequency modulations as within-subject factor and group as between-subject factor, while contrast sensitivity was the dependent variable. Receiver operating characteristic (ROC) analysis was used to characterize diagnostic performance of the new procedure in comparison with the frequency-doubling tests for preperimetric glaucoma. RESULTS. The contrast sensitivity function in both the fovea and the periphery showed an inverted "V" shape with highest sensitivity in the intermediate temporal frequencies, consistent with physiological properties of the magnocellular pathway. At the fovea, compared to the control group, the sensitivity for the glaucoma patients was slightly but not significantly reduced (P > 0.05), and there was no significant interaction between groups and temporal frequency (P > 0.05). In the periphery, patients' sensitivity was significantly lower (P < 0.001) than that of normal participants, especially in high temporal frequencies, as supported by a statistically significant interaction between groups and temporal frequency (P < 0.001). The areas under ROC curves (AUROC) obtained for the motion-on-color paradigm in the periphery were 0.957 (25 Hz), 0.870 (15 Hz), 0.758 (8 Hz), and 0.561 (3 Hz) and were 0.761 for the traditional frequency-doubling test. CONCLUSIONS. The motion-on-color paradigm revealed a loss of contrast sensitivity in the peripheral visual field in preperimetric glaucoma. When applied with stimuli at high temporal frequency, the new paradigm had higher diagnostic sensitivity and specificity than the traditional frequency-doubling test. The findings also support the viewpoint that selective evaluation of magnocellular pathway function could facilitate the earlier detection of functional defects in glaucoma before visual field defects by standard perimetry.
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