The dual-encoder has become the de facto architecture for dense retrieval. Typically, it computes the latent representations of the query and document independently, thus failing to fully capture the interactions between the query and document. To alleviate this, recent work expects to get query-informed representations of documents. During training, it expands the document with a real query, while replacing the real query with a generated pseudo query at inference. This discrepancy between training and inference makes the dense retrieval model pay more attention to the query information but ignore the document when computing the document representation. As a result, it even performs worse than the vanilla dense retrieval model, since its performance depends heavily on the relevance between the generated queries and the real query. In this paper, we propose a curriculum sampling strategy, which also resorts to the pseudo query at training and gradually increases the relevance of the generated query to the real query. In this way, the retrieval model can learn to extend its attention from the document only to both the document and query, hence getting high-quality query-informed document representations. Experimental results on several passage retrieval datasets show that our approach outperforms the previous dense retrieval methods1.
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Modern power systems will have to face difficult challenges in the years to come: frequent blackouts in urban areas caused by high power demand peaks, grid instability exacerbated by intermittent renewable generation, and global climate change amplified by rising carbon emissions. While current practices are growingly inadequate, the path to widespread adoption of artificial intelligence (AI) methods is hindered by missing aspects of trustworthiness. The CityLearn Challenge is an exemplary opportunity for researchers from multiple disciplines to investigate the potential of AI to tackle these pressing issues in the energy domain, collectively modeled as a reinforcement learning (RL) task. Multiple real-world challenges faced by contemporary RL techniques are embodied in the problem formulation. In this paper, we present a novel method using the solution function of optimization as policies to compute actions for sequential decision-making, while notably adapting the parameters of the optimization model from online observations. Algorithmically, this is achieved by an evolutionary algorithm under a novel trajectory-based guidance scheme. Formally, the global convergence property is established. Our agent ranked first in the latest 2021 CityLearn Challenge, being able to achieve superior performance in almost all metrics while maintaining some key aspects of interpretability.
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We study the expressibility and learnability of convex optimization solution functions and their multi-layer architectural extension. The main results are: \emph{(1)} the class of solution functions of linear programming (LP) and quadratic programming (QP) is a universal approximant for the $C^k$ smooth model class or some restricted Sobolev space, and we characterize the rate-distortion, \emph{(2)} the approximation power is investigated through a viewpoint of regression error, where information about the target function is provided in terms of data observations, \emph{(3)} compositionality in the form of a deep architecture with optimization as a layer is shown to reconstruct some basic functions used in numerical analysis without error, which implies that \emph{(4)} a substantial reduction in rate-distortion can be achieved with a universal network architecture, and \emph{(5)} we discuss the statistical bounds of empirical covering numbers for LP/QP, as well as a generic optimization problem (possibly nonconvex) by exploiting tame geometry. Our results provide the \emph{first rigorous analysis of the approximation and learning-theoretic properties of solution functions} with implications for algorithmic design and performance guarantees.
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Choosing the values of hyper-parameters in sparse Bayesian learning (SBL) can significantly impact performance. However, the hyper-parameters are normally tuned manually, which is often a difficult task. Most recently, effective automatic hyper-parameter tuning was achieved by using an empirical auto-tuner. In this work, we address the issue of hyper-parameter auto-tuning using neural network (NN)-based learning. Inspired by the empirical auto-tuner, we design and learn a NN-based auto-tuner, and show that considerable improvement in convergence rate and recovery performance can be achieved.
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The explosive growth of dynamic and heterogeneous data traffic brings great challenges for 5G and beyond mobile networks. To enhance the network capacity and reliability, we propose a learning-based dynamic time-frequency division duplexing (D-TFDD) scheme that adaptively allocates the uplink and downlink time-frequency resources of base stations (BSs) to meet the asymmetric and heterogeneous traffic demands while alleviating the inter-cell interference. We formulate the problem as a decentralized partially observable Markov decision process (Dec-POMDP) that maximizes the long-term expected sum rate under the users' packet dropping ratio constraints. In order to jointly optimize the global resources in a decentralized manner, we propose a federated reinforcement learning (RL) algorithm named federated Wolpertinger deep deterministic policy gradient (FWDDPG) algorithm. The BSs decide their local time-frequency configurations through RL algorithms and achieve global training via exchanging local RL models with their neighbors under a decentralized federated learning framework. Specifically, to deal with the large-scale discrete action space of each BS, we adopt a DDPG-based algorithm to generate actions in a continuous space, and then utilize Wolpertinger policy to reduce the mapping errors from continuous action space back to discrete action space. Simulation results demonstrate the superiority of our proposed algorithm to benchmark algorithms with respect to system sum rate.
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Graph structure learning aims to learn connectivity in a graph from data. It is particularly important for many computer vision related tasks since no explicit graph structure is available for images for most cases. A natural way to construct a graph among images is to treat each image as a node and assign pairwise image similarities as weights to corresponding edges. It is well known that pairwise similarities between images are sensitive to the noise in feature representations, leading to unreliable graph structures. We address this problem from the viewpoint of statistical tests. By viewing the feature vector of each node as an independent sample, the decision of whether creating an edge between two nodes based on their similarity in feature representation can be thought as a ${\it single}$ statistical test. To improve the robustness in the decision of creating an edge, multiple samples are drawn and integrated by ${\it multiple}$ statistical tests to generate a more reliable similarity measure, consequentially more reliable graph structure. The corresponding elegant matrix form named $\mathcal{B}\textbf{-Attention}$ is designed for efficiency. The effectiveness of multiple tests for graph structure learning is verified both theoretically and empirically on multiple clustering and ReID benchmark datasets. Source codes are available at https://github.com/Thomas-wyh/B-Attention.
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近年来,深度学习的时间序列增加了。对于时间序列的异常检测方案,例如金融,物联网,数据中心操作等,时间序列通常会根据各种外部因素显示非常灵活的基线。异常通过躺在远离基线的情况下揭示自己。但是,由于一些挑战,包括基线转换,缺乏标签,噪声干扰,流数据中的实时检测,可解释性等。从时间序列,即深基线网络(DBLN)。通过使用此深层网络,我们可以轻松地定位基线位置,然后提供可靠且可解释的异常检测结果。对合成和公共现实世界数据集的经验评估表明,我们纯粹的无监督算法与最新方法相比,实现了卓越的性能,并且具有良好的实际应用。
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组合多个传感器使机器人能够最大程度地提高其对环境的感知意识,并增强其对外部干扰的鲁棒性,对机器人导航至关重要。本文提出了可融合的基准测试,这是一个完整的多传感器数据集,具有多种移动机器人序列。本文提出了三项贡献。我们首先推进便携式和通用的多传感器套件,可提供丰富的感官测量值:10Hz激光镜点云,20Hz立体声框架图像,来自立体声事件相机的高速率和异步事件,来自IMU的200Hz惯性读数以及10Hz GPS信号。传感器已经在硬件中暂时同步。该设备轻巧,独立,并为移动机器人提供插件支持。其次,我们通过收集17个序列来构建数据集,该序列通过利用多个机器人平台进行数据收集来涵盖校园上各种环境。一些序列对现有的SLAM算法具有挑战性。第三,我们为将本地化和映射绩效评估提供了基础真理。我们还评估最新的大满贯方法并确定其局限性。该数据集将发布由原始传感器的设置,地面真相,校准数据和评估算法组成:https://ram-lab.com/file/site/site/multi-sensor-dataset。
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本文回顾了AIM 2022上压缩图像和视频超级分辨率的挑战。这项挑战包括两条曲目。轨道1的目标是压缩图像的超分辨率,轨迹〜2靶向压缩视频的超分辨率。在轨道1中,我们使用流行的数据集DIV2K作为培训,验证和测试集。在轨道2中,我们提出了LDV 3.0数据集,其中包含365个视频,包括LDV 2.0数据集(335个视频)和30个其他视频。在这一挑战中,有12支球队和2支球队分别提交了赛道1和赛道2的最终结果。所提出的方法和解决方案衡量了压缩图像和视频上超分辨率的最先进。提出的LDV 3.0数据集可在https://github.com/renyang-home/ldv_dataset上找到。此挑战的首页是在https://github.com/renyang-home/aim22_compresssr。
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图像美学质量评估在过去十年中很受欢迎。除数值评估外,还提出了自然语言评估(美学字幕)来描述图像的一般美学印象。在本文中,我们提出了美学属性评估,即审美属性字幕,即评估诸如组成,照明使用和颜色布置之类的美学属性。标记美学属性的注释是一项非平凡的任务,该评论限制了相应数据集的规模。我们以半自动方式构建了一个名为DPC-CAPTIONSV2的新型数据集。知识从带有完整注释的小型数据集转移到摄影网站的大规模专业评论。 DPC-CAPTIONSV2的图像包含最多4个美学属性的注释:组成,照明,颜色和主题。然后,我们根据BUTD模型和VLPSA模型提出了一种新版本的美学多属性网络(AMANV2)。 AMANV2融合了带有完整注释的小规模PCCD数据集和带有完整注释的大规模DPCCAPTIONSV2数据集的混合物的功能。 DPCCAPTIONSV2的实验结果表明,我们的方法可以预测对4种美学属性的评论,这些评论比上一个Aman模型所产生的方法更接近美学主题。通过图像字幕的评估标准,专门设计的AMANV2模型对CNN-LSTM模型和AMAN模型更好。
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