bluuebunny/crossref_metadata_2025 huggingface dataset:
Экологическая политика как фактор укрепления национальной безопасности КНР
Authors: Цинь Тинтин
Published: July 2022

В монографии проанализированы теоретико-методологические основы изучения экологической политики современных государств, раскрыты категории и основные функции этой политики, содержание основных мировых концепций взаимоотношения чело-века и природы, показано развитие экологических концепций в Китае. Проанализировано состояние окружающей среды КНР, вскрыты проблемы и тормозящие факторы в реализации государственной экологической политики Китая. Показано влияние гражданского общества и неправительственных организаций на развитие экологической политики КНР, выявлены успехи и упущения китайской экологической дипломатии. Исследован опыт сотрудничества КНР и РФ в обеспечении экологической безопасности на региональном и глобальном уровне, а также показаны пути и перспективы решения глобальных экологических проблем с участием Китая.
Time-Constrained Participatory Budgeting Under Uncertain Project Costs
Authors: Baumeister Dorothea , Boes Linus , Laußmann Christian
Published: July 2022

In participatory budgeting the stakeholders collectively decide which projects from a set of proposed projects should be implemented.

This decision underlies both time and monetary constraints.

In reality it is often impossible to figure out the exact cost of each project in advance, it is only known after a project is finished.

To reduce risk, one can implement projects one after the other to be able to react to higher costs of a previous project.

However, this will increase execution time drastically.

We generalize existing frameworks to capture this setting, study desirable properties of algorithms for this problem, and show that some desirable properties are incompatible.

Then we present and analyze algorithms that trade-off desirable properties.
Approximately EFX Allocations for Indivisible Chores
Authors: Zhou Shengwei , Wu Xiaowei
Published: July 2022

In this paper we study how to fairly allocate a set of m indivisible chores to a group of n agents, each of which has a general additive cost function on the items. Since envy-free (EF) allocation is not guaranteed to exist, we consider the notion of envy-freeness up to any item (EFX). In contrast to the fruitful results regarding the (approximation of) EFX allocations for goods, very little is known for the allocation of chores. Prior to our work, for the allocation of chores, it is known that EFX allocations always exist for two agents, or general number of agents with identical ordering cost functions. For general instances, no non-trivial approximation result regarding EFX allocation is known. In this paper we make some progress in this direction by showing that for three agents we can always compute a 5-approximation of EFX allocation in polynomial time. For n>=4 agents, our algorithm always computes an allocation that achieves an approximation ratio of 3n^2 regarding EFX. We also study the bi-valued instances, in which agents have at most two cost values on the chores, and provide polynomial time algorithms for the computation of EFX allocation when n=3, and (n-1)-approximation of EFX allocation when n>=4.
Fair Equilibria in Sponsored Search Auctions: The Advertisers’ Perspective
Authors: Birmpas Georgios , Celli Andrea , Colini-Baldeschi Riccardo , Leonardi Stefano
Published: July 2022

In this work we introduce a new class of mechanisms composed of a traditional Generalized Second Price (GSP) auction, and a fair division scheme in order to achieve some desired level of fairness between groups of Bayesian strategic advertisers. We propose two mechanisms, beta-Fair GSP and GSP-EFX, that compose GSP with, respectively, an envy-free up to one item, and an envy-free up to any item fair division scheme. The payments of GSP are adjusted in order to compensate advertisers that suffer a loss of efficiency due the fair division stage. We investigate the strategic learning implications of the deployment of sponsored search auction mechanisms that obey to such fairness criteria. We prove that, for both mechanisms, if bidders play so as to minimize their external regret they are guaranteed to reach an equilibrium with good social welfare. We also prove that the mechanisms are budget balanced, so that the payments charged by the traditional GSP mechanism are a good proxy of the total compensation offered to the advertisers. Finally, we evaluate the quality of the allocations through experiments on real-world data.
Online Hybrid Lightweight Representations Learning: Its Application to Visual Tracking
Authors: Jung Ilchae , Kim Minji , Park Eunhyeok , Han Bohyung
Published: July 2022

This paper presents a novel hybrid representation learning framework for streaming data, where an image frame in a video is modeled by an ensemble

of two distinct deep neural networks; one is a low-bit quantized network and the other is a lightweight full-precision network. The former learns coarse

primary information with low cost while the latter conveys residual information for high fidelity to original representations. The proposed parallel architecture is effective to maintain complementary information since fixed-point arithmetic can be utilized in the quantized network and the lightweight

model provides precise representations given by a compact channel-pruned network. We incorporate the hybrid representation technique into an online

visual tracking task, where deep neural networks need to handle temporal variations of target appearances in real-time. Compared to the state-of-the-art

real-time trackers based on conventional deep neural networks, our tracking algorithm demonstrates competitive accuracy on the standard benchmarks

with a small fraction of computational cost and memory footprint.
Iterative Geometry-Aware Cross Guidance Network for Stereo Image Inpainting
Authors: Li Ang , Zhao Shanshan , Qingjie Zhang , Ke Qiuhong
Published: July 2022

Currently, single image inpainting has achieved promising results based on deep convolutional neural networks. However, inpainting on stereo images with missing regions has not been explored thoroughly, which is also a significant but different problem. One crucial requirement for stereo image inpainting is stereo consistency. To achieve it, we propose an Iterative Geometry-Aware Cross Guidance Network (IGGNet). The IGGNet contains two key ingredients, i.e., a Geometry-Aware Attention(GAA) module and an Iterative Cross Guidance(ICG) strategy. The GAA module relies on the epipolar geometry cues and learns the geometry-aware guidance from one view to another, which is beneficial to make the corresponding regions in two views consistent. However, learning guidance from co-existing missing regions is challenging. To address this issue, the ICG strategy is proposed, which can alternately narrow down the missing regions of the two views in an iterative manner. Experimental results demonstrate that our proposed network outperforms the latest stereo image inpainting model and state-of-the-art single image inpainting models.
Feature Dense Relevance Network for Single Image Dehazing
Authors: Liang Yun , Huang Enze , Zhang Zifeng , Su Zhuo , Wang Dong
Published: July 2022

Existing learning-based dehazing methods do not fully use non-local information, which makes the restoration of seriously degraded region very tough. We propose a novel dehazing network by defining the Feature Dense Relevance module (FDR) and the Shallow Feature Mapping module (SFM). The FDR is defined based on multi-head attention to construct the dense relationship between different local features in the whole image. It enables the network to restore the degraded local regions by non-local information in complex scenes. In addition, the raw distant skip-connection easily leads to artifacts while it cannot deal with the shallow features effectively. Therefore, we define the SFM by combining the atmospheric scattering model and the distant skip-connection to effectively deal with the shallow features in different scales. It not only maps the degraded textures into clear textures by distant dependence, but also

reduces artifacts and color distortions effectively. We introduce contrastive loss and focal frequency loss in the network to obtain a realitic and clear image. The extensive experiments on several synthetic and real-world datasets demonstrate that our network surpasses most of the state-of-the-art methods.
Learning to Estimate Object Poses without Real Image Annotations
Authors: Lin Haotong , Peng Sida , Zhou Zhize , Zhou Xiaowei
Published: July 2022

This paper presents a simple yet effective approach for learning 6DoF object poses without real image annotations. Previous methods have attempted to train pose estimators on synthetic data, but they do not generalize well to real images due to the sim-to-real domain gap and produce inaccurate pose estimates. We find that, in most cases, the synthetically trained pose estimators are able to provide reasonable initialization for depth-based pose refinement methods which yield accurate pose estimates. Motivated by this, we propose a novel learning framework, which utilizes the accurate results of depth-based pose refinement methods to supervise the RGB-based pose estimator. Our method significantly outperforms previous self-supervised methods on several benchmarks. Even compared with fully-supervised methods that use real annotated data, we achieve competitive results without using any real annotation. The code is available at https://github.com/zju3dv/pvnet-depth-sup.
Vision Shared and Representation Isolated Network for Person Search
Authors: Liu Yang , Li Yingping , Kong Chengyu , Kong Yuqiu , Liu Shenglan , Wang Feilong
Published: July 2022

Person search is a widely-concerned computer vision task that aims to jointly solve the problems of pedestrian detection and person re-identification in panoramic scenes. However, the pedestrian detection focuses on the consistency of pedestrians, while the person re-identification attempts to extract the discriminative features of pedestrians. The inevitable conflict greatly restricts the researches on the one-stage person search methods. To address this issue, we propose a Vision Shared and Representation Isolated (VSRI) network to decouple the two conflicted subtasks simultaneously, through which two independent representations are constructed for the two subtasks. To enhance the discrimination of the re-ID representation, a Multi-Level Feature Fusion (MLFF) module is proposed. The MLFF adopts the Spatial Pyramid Feature Fusion (SPFF) module to obtain diverse features from the stem network. Moreover, the multi-head self-attention mechanism is employed to construct a Multi-head Attention Driven Extraction (MADE) module and the cascaded convolution unit is adopted to devise a Feature Decomposition and Cascaded Integration (FDCI) module, which facilitates the MLFF to obtain more discriminative representations of the pedestrians. The proposed method outperforms the state-of-the-art methods on the mainstream datasets.
Deep Video Harmonization With Color Mapping Consistency
Authors: Lu Xinyuan , Huang Shengyuan , Niu Li , Cong Wenyan , Zhang Liqing
Published: July 2022

Video harmonization aims to adjust the foreground of a composite video to make it compatible with the background. So far, video harmonization has only received limited attention and there is no public dataset for video harmonization. In this work, we construct a new video harmonization dataset HYouTube by adjusting the foreground of real videos to create synthetic composite videos. Moreover, we consider the temporal consistency in video harmonization task. Unlike previous works which establish the spatial correspondence, we design a novel framework based on the assumption of color mapping consistency, which leverages the color mapping of neighboring frames to refine the current frame. Extensive experiments on our HYouTube dataset prove the effectiveness of our proposed framework. Our dataset and code are available at https://github.com/bcmi/Video-Harmonization-Dataset-HYouTube.
Video Frame Interpolation Based on Deformable Kernel Region
Authors: Tian Haoyue , Gao Pan , Peng Xiaojiang
Published: July 2022

Video frame interpolation task has recently become more and more prevalent in the computer vision field. At present, a number of researches based on deep learning have achieved great success. Most of them are either based on optical flow information, or interpolation kernel, or a combination of these two methods. However, these methods have ignored that there are grid restrictions on the position of kernel region during synthesizing each target pixel. These limitations result in that they cannot well adapt to the irregularity of object shape and uncertainty of motion, which may lead to irrelevant reference pixels used for interpolation. In order to solve this problem, we revisit the deformable convolution for video interpolation, which can break the fixed grid restrictions on the kernel region, making the distribution of reference points more suitable for the shape of the object, and thus warp a more accurate interpolation frame. Experiments are conducted on four datasets to demonstrate the superior performance of the proposed model in comparison to the state-of-the-art alternatives.
Corner Affinity: A Robust Grouping Algorithm to Make Corner-guided Detector Great Again
Authors: Wei Haoran , Liu Chenglong , Guo Ping , Zhu Yangguang , Fu Jiamei , Wang Bing , Wang Peng
Published: July 2022

Corner-guided detector enjoys potential ability to yield precise bounding boxes. However, unreliable corner pairs, generated by heuristic grouping guidance, hinder the development of this detector. In this paper, we propose a novel corner grouping algorithm, termed as Corner Affinity, to significantly boost the reliability and robustness of corner grouping. The proposed Corner Affinity is a couple of two interactional factors, namely, 1) the structure affinity (SA), applying to generate preliminary corner pairs through the corresponding object's shallow construction information. 2) the contexts affinity (CA), running as optimizing corner pairs via embedding deeper semantic features of affiliated instances. Equipped with the Corner Affinity, a detector can produce high-quality bounding boxes upon preferable paired corner keypoints. Experimental results show the superiority of our design on multiple benchmark datasets. Specifically, for CornerNet baseline, the proposed Corner Affinity brings AP boostings of 5.8% on COCO, 35.8% on Citypersons, and 17.2% on UCAS-AOD without bells and whistles.
Multi-scale Spatial Representation Learning via Recursive Hermite Polynomial Networks
Authors: Wu Lin (Yuanbo) , Liu Deyin , Guo Xiaojie , Hong Richang , Liu Liangchen , Zhang Rui
Published: July 2022

Multi-scale representation learning aims to leverage diverse features from different layers of Convolutional Neural Networks (CNNs) for boosting the feature robustness to scale variance. For dense prediction tasks, two key properties should be satisfied: the high spatial variance across convolutional layers, and the sub-scale granularity inside a convolutional layer for fine-grained features. To pursue the two properties, this paper proposes Recursive Hermite Polynomial Networks (RHP-Nets for short). The proposed RHP-Nets consist of two major components: 1) a dilated convolution to maintain the spatial resolution across layers, and 2) a family of Hermite polynomials over a subset of dilated grids, which recursively constructs sub-scale representations to avoid the artifacts caused by naively applying the dilation convolution. The resultant sub-scale granular features are fused via trainable Hermite coefficients to form the multi-resolution representations that can be fed into the next deeper layer, and thus allowing feature interchanging at all levels. Extensive experiments are conducted to demonstrate the efficacy of our design, and reveal its superiority over state-of-the-art alternatives on a variety of image recognition tasks. Besides, introspective studies are provided to further understand the properties of our method.
Eliminating Backdoor Triggers for Deep Neural Networks Using Attention Relation Graph Distillation
Authors: Xia Jun , Wang Ting , Ding Jiepin , Wei Xian , Chen Mingsong
Published: July 2022

Due to the prosperity of Artificial Intelligence (AI) techniques, more and more backdoors are designed by adversaries to attack Deep Neural Networks (DNNs). Although the state-of-the-art method Neural Attention Distillation (NAD) can effectively erase backdoor triggers from DNNs, it still suffers from non-negligible Attack Success Rate (ASR) together with lowered classification ACCuracy (ACC), since NAD focuses on backdoor defense using attention features (i.e., attention maps) of the same order. In this paper, we introduce a novel backdoor defense framework named Attention Relation Graph Distillation (ARGD), which fully explores the correlation among attention features with different orders using our proposed Attention Relation Graphs (ARGs). Based on the alignment of ARGs between teacher and student models during knowledge distillation, ARGD can more effectively eradicate backdoors than NAD. Comprehensive experimental results show that, against six latest backdoor attacks, ARGD outperforms NAD by up to 94.85% reduction in ASR, while ACC can be improved by up to 3.23%.
Perceptual Learned Video Compression with Recurrent Conditional GAN
Authors: Yang Ren , Timofte Radu , Van Gool Luc
Published: July 2022

This paper proposes a Perceptual Learned Video Compression (PLVC) approach with recurrent conditional GAN. We employ the recurrent auto-encoder-based compression network as the generator, and most importantly, we propose a recurrent conditional discriminator, which judges raw vs. compressed video conditioned on both spatial and temporal features, including the latent representation, temporal motion and hidden states in recurrent cells. This way, the adversarial training pushes the generated video to be not only spatially photo-realistic but also temporally consistent with the groundtruth and coherent among video frames. The experimental results show that the learned PLVC model compresses video with good perceptual quality at low bit-rate, and that it outperforms the official HEVC test model (HM 16.20) and the existing learned video compression approaches for several perceptual quality metrics and user studies. The project page is available at https://github.com/RenYang-home/PLVC.
To Fold or Not to Fold: a Necessary and Sufficient Condition on Batch-Normalization Layers Folding
Authors: Yvinec Edouard , Dapogny Arnaud , Bailly Kevin
Published: July 2022

Batch-Normalization (BN) layers have become fundamental components in the evermore complex deep neural network architectures. Such models require acceleration processes for deployment on edge devices. However, BN layers add computation bottlenecks due to the sequential operation processing: thus, a key, yet often overlooked component of the acceleration process is BN layers folding. In this paper, we demonstrate that the current BN folding approaches are suboptimal in terms of how many layers can be removed. We therefore provide a necessary and sufficient condition for BN folding and a corresponding optimal algorithm. The proposed approach systematically outperforms existing baselines and allows to dramatically reduce the inference time of deep neural networks.
Enhancing the Transferability of Adversarial Examples with Random Patch
Authors: Zhang Yaoyuan , Tan Yu-an , Chen Tian , Liu Xinrui , Zhang Quanxin , Li Yuanzhang
Published: July 2022

Adversarial examples can fool deep learning models, and their transferability is critical for attacking black-box models in real-world scenarios. Existing state-of-the-art transferable adversarial attacks tend to exploit intrinsic features of objects to generate adversarial examples. This paper proposes the Random Patch Attack (RPA) to significantly improve the transferability of adversarial examples by the patch-wise random transformation that effectively highlights important intrinsic features of objects. Specifically, we introduce random patch transformations to original images to variate model-specific features. Important object-related features are preserved after aggregating the transformed images since they stay consistent in multiple transformations while model-specific elements are neutralized. The obtained essential features steer noises to perturb the object-related regions, generating the adversarial examples of superior transferability across different models. Extensive experimental results demonstrate the effectiveness of the proposed RPA. Compared to the state-of-the-art transferable attacks, our attacks improve the black-box attack success rate by 2.9\% against normally trained models, 4.7\% against defense models, and 4.6\% against vision transformers on average, reaching a maximum of 99.1\%, 93.2\%, and 87.8\%, respectively.
Hierarchical Bilevel Learning with Architecture and Loss Search for Hadamard-based Image Restoration
Authors: Zhu Guijing , Ma Long , Fan Xin , Liu Risheng
Published: July 2022

In the past few decades, Hadamard-based image restoration problems (e.g., low-light image enhancement) attract wide concerns in multiple areas related to artificial intelligence. However, existing works mostly focus on heuristically defining architecture and loss by the engineering experiences that came from extensive practices. This way brings about expensive verification costs for seeking out the optimal solution. To this end, we develop a novel hierarchical bilevel learning scheme to discover the architecture and loss simultaneously for different Hadamard-based image restoration tasks.

More concretely, we first establish a new Hadamard-inspired neural unit to aggregate domain knowledge into the network design. Then we model a triple-level optimization that consists of the architecture, loss and parameters optimizations to deliver a macro perspective for network learning. Then we introduce a new hierarchical bilevel learning scheme for solving the built triple-level model to progressively generate the desired architecture and loss. We also define an architecture search space consisting of a series of simple operations and an image quality-oriented loss search space.

Extensive experiments on three Hadamard-based image restoration tasks (including low-light image enhancement, single image haze removal and underwater image enhancement) fully verify our superiority against state-of-the-art methods.
AllSATCC: Boosting AllSAT Solving with Efficient Component Analysis
Authors: Liang Jiaxin , Ma Feifei , Zhou Junping , Yin Minghao
Published: July 2022

All Solution SAT (AllSAT) is a variant of Propositional Satisfiability, which aims to find all satisfying assignments for a given formula. AllSAT has significant applications in different domains, such as software testing, data mining, and network verification. In this paper, observing that the lack of component analysis may result in more work for algorithms with non-chronological backtracking, we propose a DPLL-based algorithm for solving AllSAT problem, named AllSATCC, which takes advantage of component analysis to reduce work repetition caused by non-chronological backtracking. The experimental results show that our algorithm outperforms the state-of-the-art algorithms on most instances.
Adapt to Adaptation: Learning Personalization for Cross-Silo Federated Learning
Authors: Luo Jun , Wu Shandong
Published: July 2022

Conventional federated learning (FL) trains one global model for a federation of clients with decentralized data, reducing the privacy risk of centralized training. However, the distribution shift across non-IID datasets, often poses a challenge to this one-model-fits-all solution. Personalized FL aims to mitigate this issue systematically. In this work, we propose APPLE, a personalized cross-silo FL framework that adaptively learns how much each client can benefit from other clients’ models. We also introduce a method to flexibly control the focus of training APPLE between global and local objectives. We empirically evaluate our method's convergence and generalization behaviors, and perform extensive experiments on two benchmark datasets and two medical imaging datasets under two non-IID settings. The results show that the proposed personalized FL framework, APPLE, achieves state-of-the-art performance compared to several other personalized FL approaches in the literature. The code is publicly available at https://github.com/ljaiverson/pFL-APPLE.
HCFRec: Hash Collaborative Filtering via Normalized Flow with Structural Consensus for Efficient Recommendation
Authors: Wang Fan , Liu Weiming , Chen Chaochao , Zhu Mengying , Zheng Xiaolin
Published: July 2022

The ever-increasing data scale of user-item interactions makes it challenging for an effective and efficient recommender system. Recently, hash-based collaborative filtering (Hash-CF) approaches employ efficient Hamming distance of learned binary representations of users and items to accelerate recommendations. However, Hash-CF often faces two challenging problems, i.e., optimization on discrete representations and preserving semantic information in learned representations. To address the above two challenges, we propose HCFRec, a novel Hash-CF approach for effective and efficient recommendations. Specifically, HCFRec not only innovatively introduces normalized flow to learn the optimal hash code by efficiently fitting a proposed approximate mixture multivariate normal distribution, a continuous but approximately discrete distribution, but also deploys a cluster consistency preserving mechanism to preserve the semantic structure in representations for more accurate recommendations. Extensive experiments conducted on six real-world datasets demonstrate the superiority of our HCFRec compared to the state-of-art methods in terms of effectiveness and efficiency.
Subgraph Neighboring Relations Infomax for Inductive Link Prediction on Knowledge Graphs
Authors: Xu Xiaohan , Zhang Peng , He Yongquan , Chao Chengpeng , Yan Chaoyang
Published: July 2022

Inductive link prediction for knowledge graph aims at predicting missing links between unseen entities, those not shown in training stage. Most previous works learn entity-specific embeddings of entities, which cannot handle unseen entities. Recent several methods utilize enclosing subgraph to obtain inductive ability. However, all these works only consider the enclosing part of subgraph without complete neighboring relations, which leads to the issue that partial neighboring relations are neglected, and sparse subgraphs are hard to be handled. To address that, we propose Subgraph Neighboring Relations Infomax, SNRI, which sufficiently exploits complete neighboring relations from two aspects: neighboring relational feature for node feature and neighboring relational path for sparse subgraph. To further model neighboring relations in a global way, we innovatively apply mutual information (MI) maximization for knowledge graph. Experiments show that SNRI outperforms existing state-of-art methods by a large margin on inductive link prediction task, and verify the effectiveness of exploring complete neighboring relations in a global way to characterize node features and reason on sparse subgraphs.
Regularized Graph Structure Learning with Semantic Knowledge for Multi-variates Time-Series Forecasting
Authors: Yu Hongyuan , Li Ting , Yu Weichen , Li Jianguo , Huang Yan , Wang Liang , Liu Alex
Published: July 2022

Multivariate time-series forecasting is a critical task for many applications, and graph time-series network is widely studied due to its capability to capture the spatial-temporal correlation simultaneously. However, most existing works focus more on learning with the explicit prior graph structure, while ignoring potential information from the implicit graph structure, yielding incomplete structure modeling. Some recent works attempts to learn the intrinsic or implicit graph structure directly, while lacking a way to combine explicit prior structure with implicit structure together. In this paper, we propose Regularized Graph Structure Learning (RGSL) model to incorporate both explicit prior structure and implicit structure together, and learn the forecasting deep networks along with the graph structure. RGSL consists of two innovative modules. First, we derive an implicit dense similarity matrix through node embedding, and learn the sparse graph structure using the Regularized Graph Generation (RGG) based on the Gumbel Softmax trick. Second, we propose a Laplacian Matrix Mixed-up Module (LM3) to fuse the explicit graph and implicit graph together. We conduct experiments on three real-word datasets. Results show that the proposed RGSL model outperforms existing graph forecasting algorithms with a notable margin, while learning meaningful graph structure simultaneously. Our code and models are made publicly available at https://github.com/alipay/RGSL.git.
MFAN: Multi-modal Feature-enhanced Attention Networks for Rumor Detection
Authors: Zheng Jiaqi , Zhang Xi , Guo Sanchuan , Wang Quan , Zang Wenyu , Zhang Yongdong
Published: July 2022

Rumor spreaders are increasingly taking advantage of multimedia content to attract and mislead news consumers on social media. Although recent multimedia rumor detection models have exploited both textual and visual features for classification, they do not integrate the social structure features simultaneously, which have shown promising performance for rumor identification. It is challenging to combine the heterogeneous multi-modal data in consideration of their complex relationships. In this work, we propose a novel Multi-modal Feature-enhanced Attention Networks (MFAN) for rumor detection, which makes the first attempt to integrate textual, visual, and social graph features in one unified framework. Specifically, it considers both the complement and alignment relationships between different modalities to achieve better fusion. Moreover, it takes into account the incomplete links in the social network data due to data collection constraints and proposes to infer hidden links to learn better social graph features. The experimental results show that MFAN can detect rumors effectively and outperform state-of-the-art methods.
On the Complexity of Enumerating Prime Implicants from Decision-DNNF Circuits
Authors: de Colnet Alexis , Marquis Pierre
Published: July 2022

We consider the problem Enum·IP of enumerating prime implicants of Boolean functions represented by decision decomposable negation normal form (dec-DNNF) circuits. We study Enum·IP from dec-DNNF within the framework of enumeration complexity and prove that it is in OutputP, the class of output polynomial enumeration problems, and more precisely in IncP, the class of polynomial incremental time enumeration problems. We then focus on two closely related, but seemingly harder, enumeration problems where further restrictions are put on the prime implicants to be generated. In the first problem, one is only interested in prime implicants representing subset-minimal abductive explanations, a notion much investigated in AI for more than thirty years. In the second problem, the target is prime implicants representing sufficient reasons, a recent yet important notion in the emerging field of eXplainable AI, since they aim to explain predictions achieved by machine learning classifiers. We provide evidence showing that enumerating specific prime implicants corresponding to subset-minimal abductive explanations or to sufficient reasons is not in OutputP.
LTL on Weighted Finite Traces: Formal Foundations and Algorithms
Authors: Dodaro Carmine , Fionda Valeria , Greco Gianluigi
Published: July 2022

LTL on finite traces (LTLf ) is a logic that attracted much attention in recent literature, for its ability to formalize the qualitative behavior of dynamical systems in several application domains. However, its practical usage is still rather limited, as LTLf cannot deal with any quantitative aspect, such as with the costs of realizing some desired behaviour. The paper fills the gap by proposing a weighting framework for LTLf encoding such quantitative aspects in the traces over which it is evaluated. The complexity of reasoning problems on weighted traces is analyzed and compared to that of standard LTLf, by considering arbitrary formulas as well as classes of formulas defined in terms of relevant syntactic restrictions. Moreover, a reasoner for LTL on weighted finite traces is presented, and its performances are assessed on benchmark data.
Causes of Effects: Learning Individual Responses from Population Data
Authors: Mueller Scott , Li Ang , Pearl Judea
Published: July 2022

The problem of individualization is crucial in almost every field of science. Identifying causes of specific observed events is likewise essential for accurate decision making as well as explanation. However, such tasks invoke counterfactual relationships, and are therefore indeterminable from population data. For example, the probability of benefiting from a treatment concerns an individual having a favorable outcome if treated and an unfavorable outcome if untreated; it cannot be estimated from experimental data, even when conditioned on fine-grained features, because we cannot test both possibilities for an individual. Tian and Pearl provided bounds on this and other probabilities of causation using a combination of experimental and observational data. Those bounds, though tight, can be narrowed significantly when structural information is available in the form of a causal model. This added information may provide the power to solve central problems, such as explainable AI, legal responsibility, and personalized medicine, all of which demand counterfactual logic. This paper derives, analyzes, and characterizes these new bounds, and illustrates some of their practical applications.
GL-RG: Global-Local Representation Granularity for Video Captioning
Authors: Yan Liqi , Wang Qifan , Cui Yiming , Feng Fuli , Quan Xiaojun , Zhang Xiangyu , Liu Dongfang
Published: July 2022

Video captioning is a challenging task as it needs to accurately transform visual understanding into natural language description. To date, state-of-the-art methods inadequately model global-local representation across video frames for caption generation, leaving plenty of room for improvement. In this work, we approach the video captioning task from a new perspective and propose a GL-RG framework for video captioning, namely a Global-Local Representation Granularity. Our GL-RG demonstrates three advantages over the prior efforts: 1) we explicitly exploit extensive visual representations from different video ranges to improve linguistic expression; 2) we devise a novel global-local encoder to produce rich semantic vocabulary to obtain a descriptive granularity of video contents across frames; 3) we develop an incremental training strategy which organizes model learning in an incremental fashion to incur an optimal captioning behavior. Experimental results on the challenging MSR-VTT and MSVD datasets show that our DL-RG outperforms recent state-of-the-art methods by a significant margin. Code is available at https://github.com/ylqi/GL-RG.
FedDUAP: Federated Learning with Dynamic Update and Adaptive Pruning Using Shared Data on the Server
Authors: Zhang Hong , Liu Ji , Jia Juncheng , Zhou Yang , Dai Huaiyu , Dou Dejing
Published: July 2022

Despite achieving remarkable performance, Federated Learning (FL) suffers from two critical challenges, i.e., limited computational resources and low training efficiency. In this paper, we propose a novel FL framework, i.e., FedDUAP, with two original contributions, to exploit the insensitive data on the server and the decentralized data in edge devices to further improve the training efficiency. First, a dynamic server update algorithm is designed to exploit the insensitive data on the server, in order to dynamically determine the optimal steps of the server update for improving the convergence and accuracy of the global model. Second, a layer-adaptive model pruning method is developed to perform unique pruning operations adapted to the different dimensions and importance of multiple layers, to achieve a good balance between efficiency and effectiveness. By integrating the two original techniques together, our proposed FL model, FedDUAP, significantly outperforms baseline approaches in terms of accuracy (up to 4.8% higher), efficiency (up to 2.8 times faster), and computational cost (up to 61.9% smaller).
DyGRAIN: An Incremental Learning Framework for Dynamic Graphs
Authors: Kim Seoyoon , Yun Seongjun , Kang Jaewoo
Published: July 2022

Graph-structured data provide a powerful representation of complex relations or interactions. Many variants of graph neural networks (GNNs) have emerged to learn graph-structured data where underlying graphs are static, although graphs in various real-world applications are dynamic (e.g., evolving structure). To consider the dynamic nature that a graph changes over time, the need for applying incremental learning (i.e., continual learning or lifelong learning) to the graph domain has been emphasized. However, unlike incremental learning on Euclidean data, graph-structured data contains dependency between the existing nodes and newly appeared nodes, resulting in the phenomenon that receptive fields of existing nodes vary by new inputs (e.g., nodes and edges). In this paper, we raise a crucial challenge of incremental learning for dynamic graphs as time-varying receptive fields, and propose a novel incremental learning framework, DyGRAIN, to mitigate time-varying receptive fields and catastrophic forgetting. Specifically, our proposed method incrementally learns dynamic graph representations by reflecting the influential change in receptive fields of existing nodes and maintaining previous knowledge of informational nodes prone to be forgotten. Our experiments on large-scale graph datasets demonstrate that our proposed method improves the performance by effectively capturing pivotal nodes and preventing catastrophic forgetting.
Multi-Armed Bandit Problem with Temporally-Partitioned Rewards: When Partial Feedback Counts
Authors: Romano Giulia , Agostini Andrea , Trovò Francesco , Gatti Nicola , Restelli Marcello
Published: July 2022

There is a rising interest in industrial online applications where data becomes available sequentially. Inspired by the recommendation of playlists to users where their preferences can be collected during the listening of the entire playlist, we study a novel bandit setting, namely Multi-Armed Bandit with Temporally-Partitioned Rewards (TP-MAB), in which the stochastic reward associated with the pull of an arm is partitioned over a finite number of consecutive rounds following the pull. This setting, unexplored so far to the best of our knowledge, is a natural extension of delayed-feedback bandits to the case in which rewards may be dilated over a finite-time span after the pull instead of being fully disclosed in a single, potentially delayed round. We provide two algorithms to address TP-MAB problems, namely, TP-UCB-FR and TP-UCB-EW, which exploit the partial information disclosed by the reward collected over time. We show that our algorithms provide better asymptotical regret upper bounds than delayed-feedback bandit algorithms when a property characterizing a broad set of reward structures of practical interest, namely α-smoothness, holds. We also empirically evaluate their performance across a wide range of settings, both synthetically generated and from a real-world media recommendation problem.
Multi-Task Personalized Learning with Sparse Network Lasso
Authors: Wang Jiankun , Sun Lu
Published: July 2022

Multi-task learning learns multiple related tasks together, in order to improve the generalization performance. Existing methods typically build a global model shared by all the samples, which saves the homogeneity but ignores the individuality (heterogeneity) of samples. Personalized learning is recently proposed to learn sample-specific local models by utilizing sample heterogeneity, however, directly applying it in the multi-task learning setting poses three key challenges: 1) model sample homogeneity, 2) prevent from over-parameterization and 3) capture task correlations. In this paper, we propose a novel multi-task personalized learning method to handle these challenges. For 1), each model is decomposed into a sum of global and local components, that saves sample homogeneity and sample heterogeneity, respectively. For 2), regularized by sparse network Lasso, the joint models are embedded into a low-dimensional subspace and exhibit sparse group structures, leading to a significantly reduced number of effective parameters. For 3), the subspace is further separated into two parts, so as to save both commonality and specificity of tasks. We develop an alternating algorithm to solve the proposed optimization problem, and extensive experiments on various synthetic and real-world datasets demonstrate its robustness and effectiveness.
Modeling Spatio-temporal Neighbourhood for Personalized Point-of-interest Recommendation
Authors: Wang Xiaolin , Sun Guohao , Fang Xiu , Yang Jian , Wang Shoujin
Published: July 2022

Point-of-interest (POI) recommendations can help users explore attractive locations, which is playing an important role in location-based social networks (LBSNs). In POI recommendations, the results are largely impacted by users' preferences. However, the existing POI methods model user and location almost separately, which cannot capture users' personal and dynamic preferences to location. In addition, they also ignore users' acceptance to distance/time of location. To overcome the limitations of the existing methods, we first introduce Knowledge Graph with temporal information (known as TKG) into POI recommendation, including both user and location with timestamps. Then, based on TKG, we propose a Spatial-Temporal Graph Convolutional Attention Network (STGCAN), a novel network that learns users' preferences on TKG by dynamically capturing the spatial-temporal neighbourhoods. Specifically, in STGCAN, we construct receptive fields on TKG to aggregate neighbourhoods of user and location respectively at each timestamp. And we measure the spatial-temporal interval as users' acceptance to distance/time with self-attention. Experiments on three real-world datasets demonstrate that the proposed model outperforms the state-of-the-art POI recommendation approaches.
Value Refinement Network (VRN)
Authors: Wöhlke Jan , Schmitt Felix , van Hoof Herke
Published: July 2022

In robotic tasks, we encounter the unique strengths of (1) reinforcement learning (RL) that can handle high-dimensional observations as well as unknown, complex dynamics and (2) planning that can handle sparse and delayed rewards given a dynamics model. Combining these strengths of RL and planning, we propose the Value Refinement Network (VRN), in this work. Our VRN is an RL-trained neural network architecture that learns to locally refine an initial (value-based) plan in a simplified (2D) problem abstraction based on detailed local sensory observations. We evaluate the VRN on simulated robotic (navigation) tasks and demonstrate that it can successfully refine sub-optimal plans to match the performance of more costly planning in the non-simplified problem. Furthermore, in a dynamic environment, the VRN still enables high task completion without global re-planning.
Ambiguity-Induced Contrastive Learning for Instance-Dependent Partial Label Learning
Authors: Xia Shi-Yu , Lv Jiaqi , Xu Ning , Geng Xin
Published: July 2022

Partial label learning (PLL) learns from a typical weak supervision, where each training instance is labeled with a set of ambiguous candidate labels (CLs) instead of its exact ground-truth label. Most existing PLL works directly eliminate, rather than exploiting the label ambiguity, since they explicitly or implicitly assume that incorrect CLs are noise independent of the instance. While a more practical setting in the wild should be instance-dependent, namely, the CLs depend on both the true label and the instance itself, such that each CL may describe the instance from some sensory channel, thereby providing some noisy but really valid information about the instance. In this paper, we leverage such additional information acquired from the ambiguity and propose AmBiguity-induced contrastive LEarning (ABLE) under the framework of contrastive learning. Specifically, for each CL of an anchor, we select a group of samples currently predicted as that class as ambiguity-induced positives, based on which we synchronously learn a representor (RP) that minimizes the weighted sum of contrastive losses of all groups and a classifier (CS) that minimizes a classification loss. Although they are circularly dependent: RP requires the ambiguity-induced positives on-the-fly induced by CS, and CS needs the first half of RP as the representation extractor, ABLE still enables RP and CS to be trained simultaneously within a coherent framework. Experiments on benchmark datasets demonstrate its substantial improvements over state-of-the-art methods for learning from the instance-dependent partially labeled data.
MemREIN: Rein the Domain Shift for Cross-Domain Few-Shot Learning
Authors: Xu Yi , Wang Lichen , Wang Yizhou , Qin Can , Zhang Yulun , Fu Yun
Published: July 2022

Few-shot learning aims to enable models generalize to new categories (query instances) with only limited labeled samples (support instances) from each category. Metric-based mechanism is a promising direction which compares feature embeddings via different metrics. However, it always fail to generalize to unseen domains due to the considerable domain gap challenge. In this paper, we propose a novel framework, MemREIN, which considers Memorized, Restitution, and Instance Normalization for cross-domain few-shot learning. Specifically, an instance normalization algorithm is explored to alleviate feature dissimilarity, which provides the initial model generalization ability. However, naively normalizing the feature would lose fine-grained discriminative knowledge between different classes. To this end, a memorized module is further proposed to separate the most refined knowledge and remember it. Then, a restitution module is utilized to restitute the discrimination ability from the learned knowledge. A novel reverse contrastive learning strategy is proposed to stabilize the distillation process. Extensive experiments on five popular benchmark datasets demonstrate that MemREIN well addresses the domain shift challenge, and significantly improves the performance up to 16.43% compared with state-of-the-art baselines.
Model-Based Offline Planning with Trajectory Pruning
Authors: Zhan Xianyuan , Zhu Xiangyu , Xu Haoran
Published: July 2022

The recent offline reinforcement learning (RL) studies have achieved much progress to make RL usable in real-world systems by learning policies from pre-collected datasets without environment interaction. Unfortunately, existing offline RL methods still face many practical challenges in real-world system control tasks, such as computational restriction during agent training and the requirement of extra control flexibility. The model-based planning framework provides an attractive alternative. However, most model-based planning algorithms are not designed for offline settings. Simply combining the ingredients of offline RL with existing methods either provides over-restrictive planning or leads to inferior performance. We propose a new light-weighted model-based offline planning framework, namely MOPP, which tackles the dilemma between the restrictions of offline learning and high-performance planning. MOPP encourages more aggressive trajectory rollout guided by the behavior policy learned from data, and prunes out problematic trajectories to avoid potential out-of-distribution samples. Experimental results show that MOPP provides competitive performance compared with existing model-based offline planning and RL approaches.