Existing 3D-aware image synthesis approaches mainly focus on generating a single canonical object and show limited capacity in composing a complex scene containing a variety of objects. This work presents DisCoScene: a 3Daware generative model for high-quality and controllable scene synthesis. The key ingredient of our method is a very abstract object-level representation (i.e., 3D bounding boxes without semantic annotation) as the scene layout prior, which is simple to obtain, general to describe various scene contents, and yet informative to disentangle objects and background. Moreover, it serves as an intuitive user control for scene editing. Based on such a prior, the proposed model spatially disentangles the whole scene into object-centric generative radiance fields by learning on only 2D images with the global-local discrimination. Our model obtains the generation fidelity and editing flexibility of individual objects while being able to efficiently compose objects and the background into a complete scene. We demonstrate state-of-the-art performance on many scene datasets, including the challenging Waymo outdoor dataset. Project page: https://snap-research.github.io/discoscene/
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Generative models, as an important family of statistical modeling, target learning the observed data distribution via generating new instances. Along with the rise of neural networks, deep generative models, such as variational autoencoders (VAEs) and generative adversarial network (GANs), have made tremendous progress in 2D image synthesis. Recently, researchers switch their attentions from the 2D space to the 3D space considering that 3D data better aligns with our physical world and hence enjoys great potential in practice. However, unlike a 2D image, which owns an efficient representation (i.e., pixel grid) by nature, representing 3D data could face far more challenges. Concretely, we would expect an ideal 3D representation to be capable enough to model shapes and appearances in details, and to be highly efficient so as to model high-resolution data with fast speed and low memory cost. However, existing 3D representations, such as point clouds, meshes, and recent neural fields, usually fail to meet the above requirements simultaneously. In this survey, we make a thorough review of the development of 3D generation, including 3D shape generation and 3D-aware image synthesis, from the perspectives of both algorithms and more importantly representations. We hope that our discussion could help the community track the evolution of this field and further spark some innovative ideas to advance this challenging task.
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类增量学习(CIL)旨在以相位逐相的方式学习多级分类器,其中仅在每个阶段提供类的子集的数据。以前的作品主要专注于初始之后减轻阶段的遗忘。但是,我们发现,在初始阶段改善CIL也是一个有希望的方向。具体而言,我们通过实验表明,在初始阶段直接鼓励CIL学习者将类似的表示类似的表示,因为在所有类别上训练的模型可以大大提升CIL性能。由此激励,我们研究了NA \“IVERY训练初始阶段模型和Oracle模型之间的差异。具体来说,由于这两个模型之间的一个主要区别是培训类的数量,我们研究了这种差异如何影响模型表示。我们发现,通过较少的培训类,每个班级的数据表示位于一个漫长而狭窄的地区;通过更多的培训类,每个阶级的陈述更统一地散射。灵感来自这种观察,我们提出了课堂上的去相关性(CWD)有效地规范了每个类的表示,以更统一地散射,从而模拟与所有类联合训练的模型(即Oracle模型)。我们的CWD易于实施,易于插入现有方法。各种各样的实验基准数据集显示CWD一直在且显着提高现有最先进方法的性能约为1 \%至3 \%。代码将被释放。
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持续学习依次解决学习不同任务的设置。尽管以前的许多解决方案,但大多数仍然遭受重大忘记或昂贵的记忆成本。在这项工作中,针对这些问题,我们首先通过信息理论的镜头来研究持续学习过程,并观察到在学习时从前一个任务中的参数丢失的遗忘。新任务。从这个角度来看,我们提出了一种名为位级信息保留(BLIP)的新的连续学习方法,其通过更新位电平的参数来保留模型参数的信息增益,这可以用参数量化方便地实现。更具体地,BLIP首先列举具有对新输入任务的权重量化的神经网络,然后估计由任务数据提供的每个参数上的信息增益,以确定要冻结的比特以防止遗忘。我们进行广泛的实验,从分类任务到加强学习任务,结果表明,我们的方法更好地生成了与以前最先进的结果相比的结果。实际上,昙花一现接近零忘记,同时只需要在连续学习中需要恒定的记忆开销。
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探讨了语言建模流行的变形金刚,用于近期解决视觉任务,例如,用于图像分类的视觉变压器(VIT)。 VIT模型将每个图像分成具有固定长度的令牌序列,然后应用多个变压器层以模拟它们的全局关系以进行分类。然而,当从像想象中的中型数据集上从头开始训练时,VIT对CNNS达到较差的性能。我们发现它是因为:1)输入图像的简单标记未能模拟相邻像素之间的重要局部结构,例如边缘和线路,导致训练采样效率低。 2)冗余注意骨干骨干设计对固定计算预算和有限的训练样本有限的具有限制性。为了克服这些限制,我们提出了一种新的令牌到令牌视觉变压器(T2T-VIT),它包含1)层 - 明智的代币(T2T)转换,通过递归聚合相邻来逐步地结构于令牌到令牌。代币进入一个令牌(令牌到令牌),这样可以建模由周围令牌所代表的本地结构,并且可以减少令牌长度; 2)一种高效的骨干,具有深度狭窄的结构,用于在实证研究后CNN建筑设计的激励变压器结构。值得注意的是,T2T-VIT将Vanilla Vit的参数计数和Mac减少了一半,同时从想象中从头开始训练时,改善了超过3.0 \%。它还优于Endnets并通过直接培训Imagenet训练来实现与MobileNets相当的性能。例如,T2T-VTO与Reset50(21.5M参数)的可比大小(21.5M参数)可以在图像分辨率384 $ \ Times 384上实现83.3 \%TOP1精度。 (代码:https://github.com/yitu-opensource/t2t-vit)
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The development of social media user stance detection and bot detection methods rely heavily on large-scale and high-quality benchmarks. However, in addition to low annotation quality, existing benchmarks generally have incomplete user relationships, suppressing graph-based account detection research. To address these issues, we propose a Multi-Relational Graph-Based Twitter Account Detection Benchmark (MGTAB), the first standardized graph-based benchmark for account detection. To our knowledge, MGTAB was built based on the largest original data in the field, with over 1.55 million users and 130 million tweets. MGTAB contains 10,199 expert-annotated users and 7 types of relationships, ensuring high-quality annotation and diversified relations. In MGTAB, we extracted the 20 user property features with the greatest information gain and user tweet features as the user features. In addition, we performed a thorough evaluation of MGTAB and other public datasets. Our experiments found that graph-based approaches are generally more effective than feature-based approaches and perform better when introducing multiple relations. By analyzing experiment results, we identify effective approaches for account detection and provide potential future research directions in this field. Our benchmark and standardized evaluation procedures are freely available at: https://github.com/GraphDetec/MGTAB.
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Image Virtual try-on aims at replacing the cloth on a personal image with a garment image (in-shop clothes), which has attracted increasing attention from the multimedia and computer vision communities. Prior methods successfully preserve the character of clothing images, however, occlusion remains a pernicious effect for realistic virtual try-on. In this work, we first present a comprehensive analysis of the occlusions and categorize them into two aspects: i) Inherent-Occlusion: the ghost of the former cloth still exists in the try-on image; ii) Acquired-Occlusion: the target cloth warps to the unreasonable body part. Based on the in-depth analysis, we find that the occlusions can be simulated by a novel semantically-guided mixup module, which can generate semantic-specific occluded images that work together with the try-on images to facilitate training a de-occlusion try-on (DOC-VTON) framework. Specifically, DOC-VTON first conducts a sharpened semantic parsing on the try-on person. Aided by semantics guidance and pose prior, various complexities of texture are selectively blending with human parts in a copy-and-paste manner. Then, the Generative Module (GM) is utilized to take charge of synthesizing the final try-on image and learning to de-occlusion jointly. In comparison to the state-of-the-art methods, DOC-VTON achieves better perceptual quality by reducing occlusion effects.
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Dynamic treatment regimes assign personalized treatments to patients sequentially over time based on their baseline information and time-varying covariates. In mobile health applications, these covariates are typically collected at different frequencies over a long time horizon. In this paper, we propose a deep spectral Q-learning algorithm, which integrates principal component analysis (PCA) with deep Q-learning to handle the mixed frequency data. In theory, we prove that the mean return under the estimated optimal policy converges to that under the optimal one and establish its rate of convergence. The usefulness of our proposal is further illustrated via simulations and an application to a diabetes dataset.
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As natural language processing (NLP) for gender bias becomes a significant interdisciplinary topic, the prevalent data-driven techniques such as large-scale language models suffer from data inadequacy and biased corpus, especially for languages with insufficient resources such as Chinese. To this end, we propose a Chinese cOrpus foR Gender bIas Probing and Mitigation CORGI-PM, which contains 32.9k sentences with high-quality labels derived by following an annotation scheme specifically developed for gender bias in the Chinese context. Moreover, we address three challenges for automatic textual gender bias mitigation, which requires the models to detect, classify, and mitigate textual gender bias. We also conduct experiments with state-of-the-art language models to provide baselines. To our best knowledge, CORGI-PM is the first sentence-level Chinese corpus for gender bias probing and mitigation.
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Off-policy evaluation (OPE) is a method for estimating the return of a target policy using some pre-collected observational data generated by a potentially different behavior policy. In some cases, there may be unmeasured variables that can confound the action-reward or action-next-state relationships, rendering many existing OPE approaches ineffective. This paper develops an instrumental variable (IV)-based method for consistent OPE in confounded Markov decision processes (MDPs). Similar to single-stage decision making, we show that IV enables us to correctly identify the target policy's value in infinite horizon settings as well. Furthermore, we propose an efficient and robust value estimator and illustrate its effectiveness through extensive simulations and analysis of real data from a world-leading short-video platform.
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