OpenRaiser/Intern-Atlas huggingface dataset:
Drive Less but Finish More: Food Delivery based on Multi-Level Workers in Spatial Crowdsourcing
Authors: Xiaojia Xu, An Liu, Guanfeng Liu, Zhixu Li, Lei Zhao
Venue: CIKM
Year: 2022

In this paper, we study the problem of on-demand food delivery in a new setting where two groups of workers -- riders and taxi drivers (drivers for short) -- cooperate with each other for better service. The riders are responsible for the first and the last mile, and the drivers are in charge of the cross-community transportation. We show this problem is generally NP-hard by a reduction from the well-known 3-dimensional matching (3DM). To tackle with this problem, we first reduce it to the maximum independent set problem and use a simple greedy strategy to design an approximate algorithm which has a polynomial time. Considering the exponents in the polynomial are not very small, we then transform the 3DM into two rounds of 2-dimensional matching and propose a fast algorithm to solve it. Though 3DM problem is NP-hard, we find the cooperation between riders and drivers form a special tripartite graph, based on which we construct a flow network and employ the min-cost max-flow algorithm to efficiently compute the exact solution. We conduct extensive experiments to show the efficiency and the effectiveness of our proposed algorithms.
Evidence-aware Document-level Relation Extraction
Authors: Tianyu Xu, Wen Hua, Jianfeng Qu, Zhixu Li, Jiajie Xu, An Liu, Lei Zhao
Venue: CIKM
Year: 2022

Document-level Relation Extraction (RE) is a promising task aiming at identifying relations of multiple entity pairs in a document. However, in most cases, a relational fact can be expressed enough via a small subset of sentences from the document, namely evidence sentence. Moreover, there often exist strong semantic correlations between evidence sentences that collaborate together to describe a specific relation. To address these challenges, we propose a novel evidence-aware model for document-level RE. Particularly, we formulate evidence sentence selection as a sequential decision problem through a crafted reinforcement learning mechanism. Considering the explosive search space of our agent, an efficient path searching strategy is executed on the converted document graph to heuristically obtain hopeful sentences and feed them to reinforcement learning. Finally, each entity pair owns a customized-filtered document for further inferring the relation between them. We conduct various experiments on two document-level RE benchmarks and achieve a remarkable improvement over previous competitive baselines, verifying the effectiveness of our method.
BidH: A Bidirectional Hierarchical Model for Nested Named Entity Recognition
Authors: Wanyang Xu, Wengen Li, Jihong Guan, Shuigeng Zhou
Venue: CIKM
Year: 2022

Nested Name Entity Recognition is to identify the entities with nested relationships from sentences, which has various applications ranging from relation extraction to semantic understanding. However, existing methods have two drawbacks, i.e., 1) error propagation when identifying entities at different nesting levels and 2) unable to uncover and utilize the complex correlations between the inner and outer entities. To address these two defects, we propose a bidirectional hierarchical(BidH) model for nested name entity recognition. BidH consists of a forward module and a backward module, where the former first extracts the inner entities and then extracts the outer ones, while the latter extracts the entities in the opposite direction. Furthermore, we design an entity masked self attention mechanism to combine the two modules by fusing their predictions and hidden states layer by layer. BidH can effectively deal with error propagation and exploit the correlations between entities at different nesting levels to improve the recognition accuracy. Experiments on the GENIA dataset show that BidH outperforms the state-of-the-art nested named entity recognition models in terms of F1 score.
Match-Prompt: Improving Multi-task Generalization Ability for Neural Text Matching via Prompt Learning
Authors: Shicheng Xu, Liang Pang, Huawei Shen, Xueqi Cheng
Venue: CIKM
Year: 2022

Text matching is a fundamental technique in both information retrieval and natural language processing. Text matching tasks share the same paradigm that determines the relationship between two given texts. The relationships vary from task to task, e.g. relevance in document retrieval, semantic alignment in paraphrase identification and answerable judgment in question answering. However, the essential signals for text matching remain in a finite scope, i.e. exact matching, semantic matching, and inference matching. Ideally, a good text matching model can learn to capture and aggregate these signals for different matching tasks to achieve competitive performance, while recent state-of-the-art text matching models, e.g. Pre-trained Language Models (PLMs), are hard to generalize. It is because the end-to-end supervised learning on task-specific dataset makes model overemphasize the data sample bias and task-specific signals instead of the essential matching signals, which ruins the generalization of model to different tasks. To overcome this problem, we adopt a specialization-generalization training strategy and refer to it as Match-Prompt. In specialization stage, descriptions of different matching tasks are mapped to only a few prompt tokens. In generalization stage, text matching model explores the essential matching signals by being trained on diverse multiple matching tasks. High diverse matching tasks avoid model fitting the data sample bias on a specific task, so that model can focus on learning the essential matching signals. Meanwhile, the prompt tokens obtained in the first step are added to the corresponding tasks to help the model distinguish different task-specific matching signals, as well as to form the basis prompt tokens for a new matching task. In this paper, we consider five common text matching tasks including document retrieval, open-domain question answering, retrieval-based dialogue, paraphrase identification, and natural language inference. Experimental results on eighteen public datasets show that Match-Prompt can improve multi-task generalization capability of PLMs in text matching and yield better in-domain multi-task, out-of-domain multi-task and new task adaptation performance than multi-task and task-specific models trained by previous fine-tuning paradigm.
Texture BERT for Cross-modal Texture Image Retrieval
Authors: Zelai Xu, Tan Yu, Ping Li
Venue: CIKM
Year: 2022

We propose Texture BERT, a model describing visual attributes of texture using natural language. To capture the rich details in texture images, we propose a group-wise compact bilinear pooling method, which represents the texture image by a set of visual patterns. The similarity between the texture image and the corresponding language description is determined by the cross-matching between the set of visual patterns from the texture image and the set of word features from the language description. We also exploit the self-attention transformer layers to provide the cross-modal context and enhance the effectiveness of matching. Our efforts achieve state-of-the-art accuracy on both text retrieval and image retrieval tasks, demonstrating the effectiveness of the proposed Texture BERT model in describing texture through natural language.
Taxonomy-Enhanced Graph Neural Networks
Authors: Lingjun Xu, Shiyin Zhang, Guojie Song, Junshan Wang, Tianshu Wu, Guojun Liu
Venue: CIKM
Year: 2022

Despite the recent success of Graph Neural Networks (GNNs), their learning pipeline is guided only by the input graph and the desired output of certain tasks, failing to capture useful patterns when not enough data are presented. Existing attempts incorporate auxiliary knowledge to mitigate this issue, most of which are not in a unified structure or hard to obtain. Noticing that nodes in graphs usually form implicit hierarchical structures, we proposed to integrate category taxonomies into the learning process of GNNs. A category taxonomy is a form of domain knowledge with a hierarchical tree structure, which is widely adopted in real-world scenarios. In this paper, we introduce Taxonomy-Enhanced Graph Neural Networks (Taxo-GNN). Specifically, we jointly optimize the taxonomy representation and node representation tasks, where categories in taxonomy are mapped to Gaussian distributions and nodes are embedded with the GNN framework. To characterize the bidirectional interaction between the taxonomy and the graph, the model is comprised of two modules, namely information distillation for taxonomy and knowledge fusion to graph. Information is first distilled from the graph and aligned with the hierarchical structure of the taxonomy in a bottom-to-top mechanism.After that, knowledge brought by the taxonomy is in turn fused to the graph convolution process, in the form of taxonomy-aware aggregation weights and taxonomy-augmented contexts. Extensive experiments on real-world datasets in multiple downstream tasks verify the effectiveness of our model.
Lightweight Unbiased Multi-teacher Ensemble for Review-based Recommendation
Authors: Guipeng Xv, Xinyi Liu, Chen Lin, Hui Li, Chenliang Li, Zhenhua Huang
Venue: CIKM
Year: 2022

Review-based recommender systems (RRS) have received an increasing interest since reviews greatly enhance recommendation quality and interpretability. However, existing RRS suffer from high computational complexity, biased recommendation and poor generalization. The three problems make them inadequate to handle real recommendation scenarios. Previous studies address each issue separately, while none of them consider solving three problems together under a unified framework. This paper presents LUME (a Lightweight Unbiased Multi-teacher Ensemble) for RRS. LUME is a novel framework that addresses the three problems simultaneously. LUME uses multi-teacher ensemble and debiased knowledge distillation to aggregate knowledge from multiple pretrained RRS, and generates a small, unbiased student recommender which generalizes better. Extensive experiments on various real-world benchmarks demonstrate that LUME successfully tackles the three problems and has superior performance than state-of-the-art RRS and knowledge distillation based RS.
Hierarchical Representation for Multi-view Clustering: From Intra-sample to Intra-view to Inter-view
Authors: Jinghua Yang, Chuan Chen, Hong-Ning Dai, Meng Ding, Lele Fu, Zibin Zheng
Venue: CIKM
Year: 2022

Multi-view clustering (MVC) aims at exploiting the consistent features within different views to divide samples into different clusters. Existing subspace-based MVC algorithms usually assume linear subspace structures and two-stage similarity matrix construction strategies, thereby posing challenges in imprecise low-dimensional subspace representation and inadequacy of exploring consistency. This paper presents a novel hierarchical representation for MVC method via the integration of intra-sample, intra-view, and inter-view representation learning models. In particular, we first adopt the deep autoencoder to adaptively map the original high-dimensional data into the latent low-dimensional representation of each sample. Second, we use the self-expression of the latent representation to explore the global similarity between samples of each view and obtain the subspace representation coefficients. Third, we construct the third-order tensor by arranging multiple subspace representation matrices and impose the tensor low-rank constraint to sufficiently explore the consistency among views. Being incorporated into a unified framework, these three models boost each other to achieve a satisfactory clustering result. Moreover, an alternating direction method of multipliers algorithm is developed to solve the challenging optimization problem. Extensive experiments on both simulated and real-world multi-view datasets show the superiority of the proposed method over eight state-of-the-art baselines.
Task Similarity Aware Meta Learning for Cold-Start Recommendation
Authors: Jieyu Yang, Zhaoxin Huan, Yong He, Ke Ding, Liang Zhang, Xiaolu Zhang, Jun Zhou, Linjian Mo
Venue: CIKM
Year: 2022

In recommender systems, content-based methods and meta-learning involved methods usually have been adopted to alleviate the item cold-start problem. The former consider utilizing item attributes at the feature level and the latter aim at learning a globally shared initialization for all tasks to achieve fast adaptation with limited data at the task level. However, content-based methods only focus on the similarity of item attributes, ignoring the relationships established by user interactions. And for tasks with different distributions, most meta-learning-based methods are difficult to achieve better performance under a single initialization. To address the limitations mentioned above and combine the strengths of both methods, we propose a Task Similarity Aware Meta-Learning (TSAML) framework from two aspects. Specifically, at the feature level, we simultaneously introduce content information and user-item relationships to exploit task similarity. At the task level, we design an automatic soft clustering module to cluster similar tasks and generate the same initialization for similar tasks. Extensive offline experiments demonstrate that the TSAML framework has superior performance and recommends cold items to preferred users more effectively than other state-of-the-art methods.
The 1st International Workshop on Federated Learning with Graph Data (FedGraph)
Authors: Carl Yang, Xiaoxiao Li, Nathalie Baracaldo, Neil Shah, Chaoyang He, Lingjuan Lyu, Lichao Sun, Salman Avestimehr
Venue: CIKM
Year: 2022

The field of graph data mining, one of the most important AI research areas, has been revolutionized by graph neural networks (GNNs), which benefit from training on real-world graph data with millions to billions of nodes and links. Unfortunately, the training data and process of GNNs involving graphs beyond millions of nodes are extremely costly on a centralized server, if not impossible. Moreover, due to the increasing concerns about data privacy, emerging data from realistic applications are naturally fragmented, forming distributed private graphs of multiple ''data silos", among which direct transferring of data is forbidden. The nascent field of federated learning (FL), which aims to enable individual clients to jointly train their models while keeping their local data decentralized and completely private, is a promising paradigm for large-scale distributed and private training of GNNs. øurs aims to bring together researchers from different backgrounds with a common interest in how to extend current FL algorithms to operate with graph data models such as GNNs. FL is an extremely hot topic of large commercial interest and has been intensively explored for machine learning with visual and textual data. The exploration from graph mining researchers and industrial practitioners is timely catching up just recently. There are many unexplored challenges and opportunities, which urges the establishment of an organized and open community to collaboratively advance the science behind it. The prospective participants of this workshop will include researchers and practitioners from both graph mining and federated learning communities, whose interests include, but are not limited to: graph analysis and mining, heterogeneous network modeling, complex data mining, large-scale machine learning, distributed systems, optimization, meta-learning, reinforcement learning, privacy, robustness, explainability, fairness, ethics, and trustworthiness.
Calibrate Automated Graph Neural Network via Hyperparameter Uncertainty
Authors: Xueying Yang, Jiamian Wang, Xujiang Zhao, Sheng Li, Zhiqiang Tao
Venue: CIKM
Year: 2022

Automated graph learning has drawn widespread research attention due to its great potential to reduce human efforts when dealing with graph data, among which hyperparameter optimization (HPO) is one of the mainstream directions and has made promising progress. However, how to obtain reliable and trustworthy prediction results with automated graph neural networks (GNN) is still quite underexplored. To this end, we investigate automated GNN calibration by marrying uncertainty estimation to the HPO problem. Specifically, we propose a hyperparameter uncertainty-induced graph convolutional network (HyperU-GCN) with a bilevel formulation, where the upper-level problem explicitly reasons uncertainties by developing a probabilistic hypernetworks through a variational Bayesian lens, while the lower-level problem learns how the GCN weights respond to a hyperparameter distribution. By squeezing model uncertainty into the hyperparameter space, the proposed HyperU-GCN could achieve calibrated predictions in a similar way to Bayesian model averaging over hyperparameters. Extensive experimental results on six public datasets were provided in terms of node classification accuracy and expected calibration error (ECE), demonstrating the effectiveness of our approach compared with several state-of-the-art uncertainty-aware and calibrated GCN methods.
gCBO: A Cost-based Optimizer for Graph Databases
Authors: Linglin Yang, Lei Yang, Yue Pang, Lei Zou
Venue: CIKM
Year: 2022

Query optimization is an especially challenging problem in graph databases due to its wide plan space and the difficulty in gathering statistics. In this demonstration, we propose a new cost-based query optimizer called gCBO for graph databases and implement it in a specific graph database (i.e., gStore). To tackle the aforementioned challenges, gCBO employs a hybrid plan enumerator based on dynamic programming, cost models that capture the characteristics of different types of joins, and a sampling-based cardinality estimation strategy that gathers the necessary statistics on-the-fly. What is more, to absorb the experience of users, we build an interactive component for gCBO, which allows users to receive the optimized execution plans with detailed information and generate their own plans for execution.
A Multi-granularity Network for Emotion-Cause Pair Extraction via Matrix Capsule
Authors: Cheng Yang, Zhongwei Zhang, Jie Ding, Wenjun Zheng, Zhiwen Jing, Ying Li
Venue: CIKM
Year: 2022

The task of Emotion-Cause Pair Extraction (ECPE) aims at extracting the clause pairs with the corresponding causality from the text.Existing approaches emphasize their multi-task settings. We argue that the clause-level encoders are ill-suited to the ECPE task where text information has many granularity features. In this paper, we design a Matrix Capsule-based multi-granularity framework (MaCa) for this task. Specifically, we first introduce a word-level encoder to obtain the token-aware representations. Then, two sentence-level extractors are used to generate emotion prediction and cause prediction. Finally, to obtain more fine-grained features of clause pairs, the matrix capsule is introduced, which can cluster the relationship of each clause pair. The empirical results on the widely used ECPE dataset show that our framework significantly outperforms most current methodsin the Emotion-Cause Extraction (ECE) and the challenging ECPE task.
Unanswerable Question Correction and Explanation over Personal Knowledge Base
Authors: An-Zi Yen, Hen-Hsen Huang, Hsin-Hsi Chen
Venue: CIKM
Year: 2022

Handling unanswerable questions in knowledge base question answering (KBQA) has been a focus in recent years. However, how to explain why a given question is unanswerable is rarely discussed. In this work, we seek not only to correct unanswerable questions based on a personal knowledge base, but also to explain the reason of the correction. We argue that different types of questions need heterogeneous subgraphs with different types of connections. We thus propose a heterogeneous subgraph aggregation network with a two-level attention mechanism to detect important entities and relations in subgraphs and attend to informative subgraphs for different questions. We conduct comprehensive experiments on five subgraphs and their combinations, with results that attest the effectiveness of incorporating heterogeneous subgraphs.
Scalable Graph Sampling on GPUs with Compressed Graph
Authors: Hongbo Yin, Yingxia Shao, Xupeng Miao, Yawen Li, Bin Cui
Venue: CIKM
Year: 2022

GPU is a powerful accelerator for parallel computation. Graph sampling is a fundamental technology for large-scale graph analysis and learning. To accelerate graph sampling using GPUs, recently some solutions like NextDoor, C-SAW have been proposed. However, these solutions cannot handle large graphs efficiently because of the massive memory footprint and expensive transfer cost between CPU and GPU. In this work, we introduce a Chunk-wise Graph Compression format (CGC) to effectively reduce the graph size and save the graph transfer cost. Meanwhile, CGC supports fast visiting any single neighbor of a vertex and is friendly to the graph sampling task. Specifically, CGC first balances the graph compression ratio and decompression efficiency by dividing a neighbor vertex list into chunks. Then it applies a new compression strategy called linear estimation to compress each chunk and allows users to visit a single vertex in O(1) time complexity. Finally, based on the CGC, we develop a scalable GPU-based graph sampling framework GraSS, and evaluate the efficiency and scalability of GraSS on both real-world and synthetic graphs. The empirical results demonstrate that GraSS can support various graph sampling methods on large graphs with high efficiency when the state-of-the-art solutions are out-of-memory or exceed the time limit.
Cognize Yourself: Graph Pre-Training via Core Graph Cognizing and Differentiating
Authors: Tao Yu, Yao Fu, Linghui Hu, Huizhao Wang, Weihao Jiang, Shiliang Pu
Venue: CIKM
Year: 2022

While Graph Neural Networks (GNNs) have become de facto criterion in graph representation learning, they still suffer from label scarcity and poor generalization. To alleviate these issues, graph pre-training has been proposed to learn universal patterns from unlabeled data via applying self-supervised tasks. Most existing graph pre-training methods only use a single self-supervised task, which will lead to insufficient knowledge mining. Recently, there are also some works that try to use multiple self-supervised tasks, however, we argue that these methods still suffer from a serious problem, which we call it graph structure impairment. That is, there actually exists structural gaps among several tasks due to the divergence of optimization objectives, which means customized graph structures should be provided for different self-supervised tasks. Graph structure impairment not only significantly hurts the generalizability of pre-trained GNNs, but also leads to suboptimal solution, and there is no study so far to address it well. Motivated by Meta-Cognitive theory, we propose a novel model named Core Graph Cognizing and Differentiating (CORE) to deal with the problem in an effective approach. Specifically, CORE consists of cognizing network and differentiating process, the former cognizes a core graph which stands for the essential structure of the graph, and the latter allows it to differentiate into several task-specific graphs for different tasks. Besides, this is also the first study to combine graph pre-training with cognitive theory to build a cognition-aware model. Several experiments have been conducted to demonstrate the effectiveness of CORE.