图对比度学习(GCL)一直是图形自学学习的新兴解决方案。 GCL的核心原理是在正视图中降低样品之间的距离,但在负视图中增加样品之间的距离。在实现有希望的性能的同时,当前的GCL方法仍然受到两个局限性:(1)增强的不可控制的有效性,该图扰动可能会产生针对语义和图形数据的特征流程的无效视图; (2)不可靠的二进制对比理由,对于非欧几里得图数据而言,难以确定构造观点的积极性和负面性。为了应对上述局限性,我们提出了一个新的对比度学习范式,即图形软对比度学习(GSCL),该范例通过排名的社区无需任何增强和二进制对比符合性,在较细性的范围内进行对比度学习。 GSCL建立在图接近的基本假设上,即连接的邻居比遥远的节点更相似。具体而言,我们在配对和列表的封闭式排名中,以保留附近的相对排名关系。此外,随着邻里规模的指数增长,考虑了更多的啤酒花,我们提出了提高学习效率的邻里抽样策略。广泛的实验结果表明,我们提出的GSCL可以始终如一地在各种公共数据集上实现与GCL相当复杂的各种公共数据集的最新性能。
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我们认为,从其嘈杂的瞬间信息中,在任何维度上学习$ k $ spike混合物的稀疏力矩问题。我们使用运输距离来测量学习混合物的准确性。先前的算法要么假设某些分离假设,使用更多的恢复力矩,要么在(超级)指数时间内运行。我们针对一维问题的算法(也称为稀疏Hausdorff Moment问题)是经典Prony方法的强大版本,我们的贡献主要在于分析。我们比以前的工作进行了全球和更严格的分析(分析了Prony方法的中间结果的扰动)。有用的技术成分是由Vandermonde矩阵定义的线性系统与Schur多项式之间的连接,这使我们能够提供独立于分离的紧密扰动,并且在其他情况下可能很有用。为了解决高维问题,我们首先通过将1维算法和分析扩展到复数来解决二维问题。我们针对高维情况的算法通过将混合物的1-D投影与随机矢量和一组混合物的一组2D投影来确定每个尖峰的坐标。我们的结果在学习主题模型和高斯混合物中有应用,这意味着改善了样本复杂性结果或在先前的工作中运行时间。
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有效地发现满足各种性能要求的分子可以显着受益药物发现行业。由于搜索整个化学空间是不可行的,因此最近的作品采用了用于目标定向分子产生的生成模型。它们倾向于利用迭代过程,优化每次迭代时的分子发生模型的参数,以产生有望的分子以进一步验证。利用评估来评估每次迭代的产生的分子,为模型优化提供方向。然而,最先前的作品需要大量的昂贵且耗时的评估,例如湿法实验和分子动态模拟,导致缺乏实用性。为了减少迭代过程中的评估,我们提出了一种在潜在空间中的成本效益的演化策略,其优化了分子潜在载波。我们采用预先训练的分子生成模型来映射潜伏和观察空间,利用大规模未标记的分子来学习化学知识。为了进一步减少昂贵的评估数量,我们将一个筛选器预先介绍为评估的代理。我们对多种优化任务进行了广泛的实验,将建议的框架与几种先进技术进行比较,表明所提出的框架更好地实现了更好的评估。
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The growing interest in intelligent services and privacy protection for mobile devices has given rise to the widespread application of federated learning in Multi-access Edge Computing (MEC). Diverse user behaviors call for personalized services with heterogeneous Machine Learning (ML) models on different devices. Federated Multi-task Learning (FMTL) is proposed to train related but personalized ML models for different devices, whereas previous works suffer from excessive communication overhead during training and neglect the model heterogeneity among devices in MEC. Introducing knowledge distillation into FMTL can simultaneously enable efficient communication and model heterogeneity among clients, whereas existing methods rely on a public dataset, which is impractical in reality. To tackle this dilemma, Federated MultI-task Distillation for Multi-access Edge CompuTing (FedICT) is proposed. FedICT direct local-global knowledge aloof during bi-directional distillation processes between clients and the server, aiming to enable multi-task clients while alleviating client drift derived from divergent optimization directions of client-side local models. Specifically, FedICT includes Federated Prior Knowledge Distillation (FPKD) and Local Knowledge Adjustment (LKA). FPKD is proposed to reinforce the clients' fitting of local data by introducing prior knowledge of local data distributions. Moreover, LKA is proposed to correct the distillation loss of the server, making the transferred local knowledge better match the generalized representation. Experiments on three datasets show that FedICT significantly outperforms all compared benchmarks in various data heterogeneous and model architecture settings, achieving improved accuracy with less than 1.2% training communication overhead compared with FedAvg and no more than 75% training communication round compared with FedGKT.
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With the development of natural language processing techniques(NLP), automatic diagnosis of eye diseases using ophthalmology electronic medical records (OEMR) has become possible. It aims to evaluate the condition of both eyes of a patient respectively, and we formulate it as a particular multi-label classification task in this paper. Although there are a few related studies in other diseases, automatic diagnosis of eye diseases exhibits unique characteristics. First, descriptions of both eyes are mixed up in OEMR documents, with both free text and templated asymptomatic descriptions, resulting in sparsity and clutter of information. Second, OEMR documents contain multiple parts of descriptions and have long document lengths. Third, it is critical to provide explainability to the disease diagnosis model. To overcome those challenges, we present an effective automatic eye disease diagnosis framework, NEEDED. In this framework, a preprocessing module is integrated to improve the density and quality of information. Then, we design a hierarchical transformer structure for learning the contextualized representations of each sentence in the OEMR document. For the diagnosis part, we propose an attention-based predictor that enables traceable diagnosis by obtaining disease-specific information. Experiments on the real dataset and comparison with several baseline models show the advantage and explainability of our framework.
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Free-text rationales (FTRs) follow how humans communicate by explaining reasoning processes via natural language. A number of recent works have studied how to improve language model (LM) generalization by using FTRs to teach LMs the correct reasoning processes behind correct task outputs. These prior works aim to learn from FTRs by appending them to the LM input or target output, but this may introduce an input distribution shift or conflict with the task objective, respectively. We propose KNIFE, which distills FTR knowledge from an FTR-augmented teacher LM (takes both task input and FTR) to a student LM (takes only task input), which is used for inference. Crucially, the teacher LM's forward computation has a bottleneck stage in which all of its FTR states are masked out, which pushes knowledge from the FTR states into the task input/output states. Then, FTR knowledge is distilled to the student LM by training its task input/output states to align with the teacher LM's. On two question answering datasets, we show that KNIFE significantly outperforms existing FTR learning methods, in both fully-supervised and low-resource settings.
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Federated learning (FL) allows multiple clients cooperatively train models without disclosing local data. However, the existing works fail to address all these practical concerns in FL: limited communication resources, dynamic network conditions and heterogeneous client properties, which slow down the convergence of FL. To tackle the above challenges, we propose a heterogeneity-aware FL framework, called FedCG, with adaptive client selection and gradient compression. Specifically, the parameter server (PS) selects a representative client subset considering statistical heterogeneity and sends the global model to them. After local training, these selected clients upload compressed model updates matching their capabilities to the PS for aggregation, which significantly alleviates the communication load and mitigates the straggler effect. We theoretically analyze the impact of both client selection and gradient compression on convergence performance. Guided by the derived convergence rate, we develop an iteration-based algorithm to jointly optimize client selection and compression ratio decision using submodular maximization and linear programming. Extensive experiments on both real-world prototypes and simulations show that FedCG can provide up to 5.3$\times$ speedup compared to other methods.
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With the evergrowing sizes of pre-trained models (PTMs), it has been an emerging practice to only provide the inference APIs for users, namely model-as-a-service (MaaS) setting. To adapt PTMs with model parameters frozen, most current approaches focus on the input side, seeking for powerful prompts to stimulate models for correct answers. However, we argue that input-side adaptation could be arduous due to the lack of gradient signals and they usually require thousands of API queries, resulting in high computation and time costs. In light of this, we present Decoder Tuning (DecT), which in contrast optimizes task-specific decoder networks on the output side. Specifically, DecT first extracts prompt-stimulated output scores for initial predictions. On top of that, we train an additional decoder network on the output representations to incorporate posterior data knowledge. By gradient-based optimization, DecT can be trained within several seconds and requires only one PTM query per sample. Empirically, we conduct extensive natural language understanding experiments and show that DecT significantly outperforms state-of-the-art algorithms with a $10^3\times$ speed-up.
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Anomaly detection is defined as discovering patterns that do not conform to the expected behavior. Previously, anomaly detection was mostly conducted using traditional shallow learning techniques, but with little improvement. As the emergence of graph neural networks (GNN), graph anomaly detection has been greatly developed. However, recent studies have shown that GNN-based methods encounter challenge, in that no graph anomaly detection algorithm can perform generalization on most datasets. To bridge the tap, we propose a multi-view fusion approach for graph anomaly detection (Mul-GAD). The view-level fusion captures the extent of significance between different views, while the feature-level fusion makes full use of complementary information. We theoretically and experimentally elaborate the effectiveness of the fusion strategies. For a more comprehensive conclusion, we further investigate the effect of the objective function and the number of fused views on detection performance. Exploiting these findings, our Mul-GAD is proposed equipped with fusion strategies and the well-performed objective function. Compared with other state-of-the-art detection methods, we achieve a better detection performance and generalization in most scenarios via a series of experiments conducted on Pubmed, Amazon Computer, Amazon Photo, Weibo and Books. Our code is available at https://github.com/liuyishoua/Mul-Graph-Fusion.
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Reinforcement-learning agents seek to maximize a reward signal through environmental interactions. As humans, our contribution to the learning process is through designing the reward function. Like programmers, we have a behavior in mind and have to translate it into a formal specification, namely rewards. In this work, we consider the reward-design problem in tasks formulated as reaching desirable states and avoiding undesirable states. To start, we propose a strict partial ordering of the policy space. We prefer policies that reach the good states faster and with higher probability while avoiding the bad states longer. Next, we propose an environment-independent tiered reward structure and show it is guaranteed to induce policies that are Pareto-optimal according to our preference relation. Finally, we empirically evaluate tiered reward functions on several environments and show they induce desired behavior and lead to fast learning.
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