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 \url{https://github.com/zhufq00/mcnc}.
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Recently, segmentation-based methods are quite popular in scene text detection, which mainly contain two steps: text kernel segmentation and expansion. However, the segmentation process only considers each pixel independently, and the expansion process is difficult to achieve a favorable accuracy-speed trade-off. In this paper, we propose a Context-aware and Boundary-guided Network (CBN) to tackle these problems. In CBN, a basic text detector is firstly used to predict initial segmentation results. Then, we propose a context-aware module to enhance text kernel feature representations, which considers both global and local contexts. Finally, we introduce a boundary-guided module to expand enhanced text kernels adaptively with only the pixels on the contours, which not only obtains accurate text boundaries but also keeps high speed, especially on high-resolution output maps. In particular, with a lightweight backbone, the basic detector equipped with our proposed CBN achieves state-of-the-art results on several popular benchmarks, and our proposed CBN can be plugged into several segmentation-based methods. Code will be available on https://github.com/XiiZhao/cbn.pytorch.
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Incorporating external knowledge into the response generation process is essential to building more helpful and reliable dialog agents. However, collecting knowledge-grounded conversations is often costly, calling for a better pre-trained model for grounded dialog generation that generalizes well w.r.t. different types of knowledge. In this work, we propose KPT (Keyword-guided Pre-Training), a novel self-supervised pre-training method for grounded dialog generation without relying on extra knowledge annotation. Specifically, we use a pre-trained language model to extract the most uncertain tokens in the dialog as keywords. With these keywords, we construct two kinds of knowledge and pre-train a knowledge-grounded response generation model, aiming at handling two different scenarios: (1) the knowledge should be faithfully grounded; (2) it can be selectively used. For the former, the grounding knowledge consists of keywords extracted from the response. For the latter, the grounding knowledge is additionally augmented with keywords extracted from other utterances in the same dialog. Since the knowledge is extracted from the dialog itself, KPT can be easily performed on a large volume and variety of dialogue data. We considered three data sources (open-domain, task-oriented, conversational QA) with a total of 2.5M dialogues. We conduct extensive experiments on various few-shot knowledge-grounded generation tasks, including grounding on dialog acts, knowledge graphs, persona descriptions, and Wikipedia passages. Our comprehensive experiments and analyses demonstrate that KPT consistently outperforms state-of-the-art methods on these tasks with diverse grounding knowledge.
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This paper studies the problem of stochastic continuum-armed bandit with constraints (SCBwC), where we optimize a black-box reward function $f(x)$ subject to a black-box constraint function $g(x)\leq 0$ over a continuous space $\mathcal X$. We model reward and constraint functions via Gaussian processes (GPs) and propose a Rectified Pessimistic-Optimistic Learning framework (RPOL), a penalty-based method incorporating optimistic and pessimistic GP bandit learning for reward and constraint functions, respectively. We consider the metric of cumulative constraint violation $\sum_{t=1}^T(g(x_t))^{+},$ which is strictly stronger than the traditional long-term constraint violation $\sum_{t=1}^Tg(x_t).$ The rectified design for the penalty update and the pessimistic learning for the constraint function in RPOL guarantee the cumulative constraint violation is minimal. RPOL can achieve sublinear regret and cumulative constraint violation for SCBwC and its variants (e.g., under delayed feedback and non-stationary environment). These theoretical results match their unconstrained counterparts. Our experiments justify RPOL outperforms several existing baseline algorithms.
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kNN-MT presents a new paradigm for domain adaptation by building an external datastore, which usually saves all target language token occurrences in the parallel corpus. As a result, the constructed datastore is usually large and possibly redundant. In this paper, we investigate the interpretability issue of this approach: what knowledge does the NMT model need? We propose the notion of local correctness (LAC) as a new angle, which describes the potential translation correctness for a single entry and for a given neighborhood. Empirical study shows that our investigation successfully finds the conditions where the NMT model could easily fail and need related knowledge. Experiments on six diverse target domains and two language-pairs show that pruning according to local correctness brings a light and more explainable memory for kNN-MT domain adaptation.
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Modality representation learning is an important problem for multimodal sentiment analysis (MSA), since the highly distinguishable representations can contribute to improving the analysis effect. Previous works of MSA have usually focused on multimodal fusion strategies, and the deep study of modal representation learning was given less attention. Recently, contrastive learning has been confirmed effective at endowing the learned representation with stronger discriminate ability. Inspired by this, we explore the improvement approaches of modality representation with contrastive learning in this study. To this end, we devise a three-stages framework with multi-view contrastive learning to refine representations for the specific objectives. At the first stage, for the improvement of unimodal representations, we employ the supervised contrastive learning to pull samples within the same class together while the other samples are pushed apart. At the second stage, a self-supervised contrastive learning is designed for the improvement of the distilled unimodal representations after cross-modal interaction. At last, we leverage again the supervised contrastive learning to enhance the fused multimodal representation. After all the contrast trainings, we next achieve the classification task based on frozen representations. We conduct experiments on three open datasets, and results show the advance of our model.
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实体对齐(EA)的目的是在不同的知识图(kgs)中找到指代现实世界中同一对象的实体。最近的研究结合了时间信息,以增强KGS的表示。暂时KGS(TKG)之间的EA的现有方法利用时间感知的注意机制将关系和时间信息纳入实体嵌入中。该方法通过使用时间信息优于先前的方法。但是,我们认为,由于大多数TKG具有统一的时间表示,因此不必学习kgs中的时间信息的嵌入。因此,我们提出了一个简单的图形神经网络(GNN)模型,并结合了时间信息匹配机制,该模型以更少的时间和更少的参数实现了更好的性能。此外,由于对齐种子很难在现实世界应用中标记,因此我们还提出了一种通过TKG的时间信息生成无监督比对种子的方法。公共数据集的广泛实验表明,我们的监督方法显着优于先前的方法,而无监督的方法具有竞争性能。
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这项工作解决了中央机器学习问题的问题,即在分布(OOD)测试集上的性能降解问题。这个问题在基于医学成像的诊断系统中尤为明显,该系统似乎是准确的,但在新医院/数据集中进行测试时失败。最近的研究表明,该系统可能会学习快捷方式和非相关功能,而不是可推广的功能,即所谓的良好功能。我们假设对抗性训练可以消除快捷方式功能,而显着性训练可以滤除非相关功能。两者都是OOD测试集的性能降解的滋扰功能。因此,我们为深度神经网络制定了一种新颖的模型培训方案,以学习分类和/或检测任务的良好功能,以确保在OOD测试集上的概括性性能。实验结果定性和定量证明了我们使用基准CXR图像数据集在分类任务上的基准CXR图像数据集的出色性能。
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玻璃在现实世界中非常普遍。受玻璃区域的不确定性以及玻璃背后的各种复杂场景的影响,玻璃的存在对许多计算机视觉任务构成了严重的挑战,从而使玻璃分割成为重要的计算机视觉任务。玻璃没有自己的视觉外观,而只能传输/反映其周围环境的外观,从而与其他常见对象根本不同。为了解决此类具有挑战性的任务,现有方法通常会探索并结合深网络中不同特征级别的有用线索。由于存在级别不同的特征之间的特征差距,即,深层特征嵌入了更多高级语义,并且更好地定位目标对象,而浅层特征具有更大的空间尺寸,并保持更丰富,更详细的低级信息,因此,将这些特征融合到天真的融合将导致亚最佳溶液。在本文中,我们将有效的特征融合到两个步骤中,以朝着精确的玻璃分割。首先,我们试图通过开发可区分性增强(DE)模块来弥合不同级别特征之间的特征差距,该模块使特定于级别的特征成为更具歧视性的表示,从而减轻了融合不兼容的特征。其次,我们设计了一个基于焦点和探索的融合(FEBF)模块,以通过突出显示常见并探索级别差异特征之间的差异,从而在融合过程中丰富挖掘有用的信息。
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审核数据出处(ADP),即如果使用某个数据来训练机器学习模型,则审核是数据出处的重要问题。在某些条件下,例如标签信息的可用性和目标模型的培训协议的知识,现有的审核技术(例如影子审计方法)已经证明了任务的可行性。不幸的是,这两种情况在实际应用中通常无法使用。在本文中,我们通过差异审核(DPDA)介绍数据出处,这是一个实用的框架,用于基于统计学上显着的差异,即在精心设计的转换之后,通过不同的方法进行审核数据出处,从目标模型的训练集中扰动输入数据将结果结果与模型的非训练集相比,输出的变化更大。该框架允许审核员将培训数据与非训练数据区分开,而无需借助标记的输出数据训练任何阴影模型。此外,我们提出了两个有效的审核函数实现,即一个加性功能和一个乘法。我们报告对现实世界数据集的评估,以证明我们提出的审计技术的有效性。
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