OpenRaiser/Intern-Atlas huggingface dataset:
Deepcas: An end-to-end predictor of information cascades
Authors: Cheng Li, Jiaqi Ma, Xiaoxiao Guo, Qiaozhu Mei
Venue: Conference WWW 2017
Year: 2017

Information cascades, effectively facilitated by most social network platforms, are recognized as a major factor in almost every social success and disaster in these networks. Can cascades be predicted? While many believe that they are inherently unpredictable, recent work has shown that some key properties of information cascades, such as size, growth, and shape, can be predicted by a machine learning algorithm that combines many features. These predictors all depend on a bag of hand-crafting features to represent the cascade network and the global network structures. Such features, always carefully and sometimes mysteriously designed, are not easy to extend or to generalize to a different platform or domain. Inspired by the recent successes of deep learning in multiple data mining tasks, we investigate whether an end-to-end deep learning approach could effectively predict the future size of cascades. Such a method automatically learns the representation of individual cascade graphs in the context of the global network structure, without hand-crafted features or heuristics. We find that node embeddings fall short of predictive power, and it is critical to learn the representation of a cascade graph as a whole. We present algorithms that learn the representation of cascade graphs in an end-to-end manner, which significantly improve the performance of cascade prediction over strong baselines including feature based methods, node embedding methods, and graph kernel methods. Our results also provide interesting implications for cascade prediction in general.
Exploring entity-centric networks in entangled news streams
Authors: Andreas Spitz, Michael Gertz
Venue: Conference WWW 2018
Year: 2018

The increasing number of news outlets and the frequency of the news cycle have made it all but impossible to obtain the full picture from online news. Consolidating news from different sources has thus become a necessity in online news processing. Despite the amount of research that has been devoted to different aspects of new event detection and tracking in news streams, solid solutions for such entangled streams of full news articles are still lacking. Many existing works focus on streams of microblogs since the analysis of news articles raises the additional problem of summarizing or extracting the relevant sections of articles. For the consolidation of identified news snippets, schemes along numerous different dimensions have been proposed, including publication time, temporal expressions, geo-spatial references, named entities, and topics. The granularity of aggregated news snippets then includes such diverse aspects as events, incidents, threads, or topics for various subdivisions of news articles. To support this variety of granularity levels, we propose a comprehensive network model for the representation of multiple entangled streams of news documents. Unlike previous methods, the model is geared towards entity-centric explorations and enables the consolidation of news along all dimensions, including the context of entity mentions. Since the model also serves as a reverse index, it supports explorations along the dimensions of sentences or documents for an encompassing view on news events. We evaluate the performance of our model on a large collection of entangled news streams from major news outlets of English speaking countries and a ground truth that we generate from event summaries in the Wikipedia Current Events portal.
A duo-generative approach to explainable multimodal covid-19 misinformation detection
Authors: Lanyu Shang, Ziyi Kou, Yang Zhang, Dong Wang
Venue: Conference WWW 2022
Year: 2022

This paper focuses on a critical problem of explainable multimodal COVID-19 misinformation detection where the goal is to accurately detect misleading information in multimodal COVID-19 news articles and provide the reason or evidence that can explain the detection results. Our work is motivated by the lack of judicious study of the association between different modalities (e.g., text and image) of the COVID-19 news content in current solutions. In this paper, we present a generative approach to detect multimodal COVID-19 misinformation by investigating the cross-modal association between the visual and textual content that is deeply embedded in the multimodal news content. Two critical challenges exist in developing our solution: 1) how to accurately assess the consistency between the visual and textual content of a multimodal COVID-19 news article? 2) How to effectively retrieve useful information from the unreliable user comments to explain the misinformation detection results? To address the above challenges, we develop a duo-generative explainable misinformation detection (DGExplain) framework that explicitly explores the cross-modal association between the news content in different modalities and effectively exploits user comments to detect and explain misinformation in multimodal COVID-19 news articles. We evaluate DGExplain on two real-world multimodal COVID-19 news datasets. Evaluation results demonstrate that DGExplain significantly outperforms state-of-the-art baselines in terms of the accuracy of multimodal COVID-19 misinformation detection and the explainability of detection explanations.
Surrogate representation learning with isometric mapping for gray-box graph adversarial attacks
Authors: Zihan Liu, Yun Luo, Zelin Zang, Stan Z. Li
Venue: Conference WSDM 2022
Year: 2022

Gray-box graph attacks aim at disrupting the performance of the victim model by using inconspicuous attacks with limited knowledge of the victim model. The parameters of the victim model and the labels of the test nodes are invisible to the attacker. To obtain the gradient on the node attributes or graph structure, the attacker constructs an imaginary surrogate model trained under supervision. However, there is a lack of discussion on the training of surrogate models and the robustness of provided gradient information. The general node classification model loses the topology of the nodes on the graph, which is, in fact, an exploitable prior for the attacker. This paper investigates the effect of representation learning of surrogate models on the transferability of gray-box graph adversarial attacks. To reserve the topology in the surrogate embedding, we propose Surrogate Representation Learning with Isometric Mapping (SRLIM). By using Isometric mapping method, our proposed SRLIM can constrain the topological structure of nodes from the input layer to the embedding space, that is, to maintain the similarity of nodes in the propagation process. Experiments prove the effectiveness of our approach through the improvement in the performance of the adversarial attacks generated by the gradient-based attacker in untargeted poisoning gray-box setups.
Hierarchical RNN with Static Sentence- Level Attention for Text-Based Speaker Change Detection
Authors: Zhao Meng, Lili Mou, Zhi Jin
Venue: Conference CIKM 2017
Year: 2017

Speaker change detection (SCD) is an important task in dialog modeling. Our paper addresses the problem of text-based SCD, which differs from existing audio-based studies and is useful in various scenarios, for example, processing dialog transcripts where speaker identities are missing (e.g., OpenSubtitle), and enhancing audio SCD with textual information. We formulate text-based SCD as a matching problem of utterances before and after a certain decision point; we propose a hierarchical recurrent neural network (RNN) with static sentence-level attention. Experimental results show that neural networks consistently achieve better performance than feature-based approaches, and that our attention-based model significantly outperforms non-attention neural networks.
Continuous-time dynamic graph learning via neural interaction processes
Authors: Xiaofu Chang, Xuqin Liu, Jianfeng Wen, Shuang Li, Yanming Fang, Le Song, Yuan Qi
Venue: Conference CIKM 2020
Year: 2020

Dynamic graphs such as the user-item interactions graphs and financial transaction networks are ubiquitous nowadays. While numerous representation learning methods for static graphs have been proposed, the study of dynamic graphs is still in its infancy. A main challenge of modeling dynamic graphs is how to effectively encode temporal and structural information into nonlinear and compact dynamic embeddings. To achieve this, we propose a principled graph-neural-based approach to learn continuous-time dynamic embeddings. We first define a temporal dependency interaction graph(TDIG) that is induced from sequences of interaction data. Based on the topology of this TDIG, we develop a dynamic message passing neural network named TDIG-MPNN, which can capture the fine-grained global and local information on TDIG. In addition, to enhance the quality of continuous-time dynamic embeddings, a novel selection mechanism comprised of two successive steps, i.e., co-attention and gating, is applied before the above TDIG-MPNN layer to adjust the importance of the nodes by considering high-order correlation between interactive nodes' k-depth neighbors on TDIG. Finally, we cast our learning problem in the framework of temporal point processes (TPPs) where we use TDIG-MPNN to design a neural intensity function for the dynamic interaction processes. Our model achieves superior performance over alternatives on temporal interaction prediction (including tranductive and inductive tasks) on multiple datasets.
Cascade-lstm: A tree-structured neural classifier for detecting misinformation cascades
Authors: Francesco Ducci, Mathias Kraus, Stefan Feuerriegel
Venue: Conference KDD 2020
Year: 2020

Misinformation in social media - such as fake news, rumors, or other forms of deceptive content - poses a significant threat to society and, hence, scalable strategies for an early detection of online cascades with misinformation are in dire need. The prominent approach in detecting online cascades with misinformation builds upon neural networks based on sequences of simple structural features of the propagation dynamics (e.g., cascade size, average retweeting time). However, these structural features neglect large parts of the information in the cascade. As a remedy, we propose a novel tree-structured neural network named Cascade-LSTM.
Dual sequential prediction models linking sequential recommendation and information dissemination
Authors: Qitian Wu, Yirui Gao, Xiaofeng Gao, Paul Weng, Guihai Chen
Venue: Conference KDD 2019
Year: 2019

Sequential recommendation and information dissemination are two traditional problems for sequential information retrieval. The common goal of the two problems is to predict future user-item interactions based on past observed interactions. The difference is that the former deals with users' histories of clicked items, while the latter focuses on items' histories of infected users.In this paper, we take a fresh view and propose dual sequential prediction models that unify these two thinking paradigms. One user-centered model takes a user's historical sequence of interactions as input, captures the user's dynamic states, and approximates the conditional probability of the next interaction for a given item based on the user's past clicking logs. By contrast, one item-centered model leverages an item's history, captures the item's dynamic states, and approximates the conditional probability of the next interaction for a given user based on the item's past infection records. To take advantage of the dual information, we design a new training mechanism which lets the two models play a game with each other and use the predicted score from the opponent to design a feedback signal to guide the training. We show that the dual models can better distinguish false negative samples and true negative samples compared with single sequential recommendation or information dissemination models. Experiments on four real-world datasets demonstrate the superiority of proposed model over some strong baselines as well as the effectiveness of dual training mechanism between two models.
Budget management strategies in repeated auctions
Authors: Santiago R. Balseiro, Anthony Kim, Mohammad Mahdian, Vahab S. Mirrokni
Venue: Conference WWW 2017
Year: 2017

In online advertising, advertisers purchase ad placements by participating in a long sequence of repeated auctions. One of the most important features advertising platforms often provide, and advertisers often use, is budget management, which allows advertisers to control their cumulative expenditures. Advertisers typically declare the maximum daily amount they are willing to pay, and the platform adjusts allocations and payments to guarantee that cumulative expenditures do not exceed budgets. There are multiple ways to achieve this goal, and each one, when applied to all budget-constrained advertisers simultaneously, steers the system toward a different equilibrium. While previous research focused on online stochastic optimization techniques or game-theoretic equilibria of such settings, our goal in this paper is to compare the ``system equilibria'' of a range of budget management strategies in terms of the seller's profit and buyers' utility. In particular, we consider six different budget management strategies including probabilistic throttling, thresholding, bid shading, reserve pricing, and multiplicative boosting. We show these methods admit a system equilibrium in a rather general setting, and prove dominance relations between them in a simplified setting. Our study sheds light on the impact of budget management strategies on the tradeoff between the seller's profit and buyers' utility. Finally, we also empirically compare the system equilibria of these strategies using real ad auction data in sponsored search and randomly generated bids. The empirical study confirms our theoretical findings about the relative performances of budget management strategies.
Auction design for roi-constrained buyers
Authors: Negin Golrezaei, Ilan Lobel, Renato Paes Leme
Venue: Conference WWW 2021
Year: 2021

We combine theory and empirics to (i) show that some buyers in online advertising markets are financially constrained and (ii) demonstrate how to design auctions that take into account such financial constraints. We use data from a field experiment where reserve prices were randomized on Google’s advertising exchange (AdX). We find that, contrary to the predictions of classical auction theory, a significant set of buyers lowers their bids when reserve prices go up. We show that this behavior can be explained if we assume buyers have constraints on their minimum return on investment (ROI). We proceed to design auctions for ROI-constrained buyers. We show that optimal auctions for symmetric ROI-constrained buyers are either second-price auctions with reduced reserve prices or subsidized second-price auctions. For asymmetric buyers, the optimal auction involves a modification of virtual values. Going back to the data, we show that using ROI-aware optimal auctions can lead to large revenue gains and large welfare gains for buyers.
Lsh forest: self-tuning indexes for similarity search
Authors: Mayank Bawa, Tyson Condie, Prasanna Ganesan
Venue: Conference WWW 2005
Year: 2005

We consider the problem of indexing high-dimensional data for answering (approximate) similarity-search queries. Similarity indexes prove to be important in a wide variety of settings: Web search engines desire fast, parallel, main-memory-based indexes for similarity search on text data; database systems desire disk-based similarity indexes for high-dimensional data, including text and images; peer-to-peer systems desire distributed similarity indexes with low communication cost. We propose an indexing scheme called LSH Forest which is applicable in all the above contexts. Our index uses the well-known technique of locality-sensitive hashing (LSH), but improves upon previous designs by (a) eliminating the different data-dependent parameters for which LSH must be constantly hand-tuned, and (b) improving on LSH's performance guarantees for skewed data distributions while retaining the same storage and query overhead. We show how to construct this index in main memory, on disk, in parallel systems, and in peer-to-peer systems. We evaluate the design with experiments on multiple text corpora and demonstrate both the self-tuning nature and the superior performance of LSH Forest.
Elite: Robust deep anomaly detection with meta gradient
Authors: Huayi Zhang, Lei Cao, Peter M. VanNostrand, Samuel Madden, Elke A. Rundensteiner
Venue: Conference KDD 2021
Year: 2021

Deep Learning techniques have been widely used in detecting anomalies from complex data. Most of these techniques are either unsupervised or semi-supervised because of a lack of a large number of labeled anomalies. However, they typically rely on a clean training data not polluted by anomalies to learn the distribution of the normal data. Otherwise, the learned distribution tends to be distorted and hence ineffective in distinguishing between normal and abnormal data. To solve this problem, we propose a novel approach called ELITE that uses a small number of labeled examples to infer the anomalies hidden in the training samples. It then turns these anomalies into useful signals that help to better detect anomalies from user data. Unlike the classical semi-supervised classification strategy which uses labeled examples as training data, ELITE uses them as validation set. It leverages the gradient of the validation loss to predict if one training sample is abnormal. The intuition is that correctly identifying the hidden anomalies could produce a better deep anomaly model with reduced validation loss. Our experiments on public benchmark datasets show that ELITE achieves up to 30% improvement in ROC AUC comparing to the state-of-the-art, yet robust to polluted training data.
Subsampling for efficient and effective unsupervised outlier detection ensembles
Authors: Arthur Zimek, Matthew Gaudet, Ricardo J. G. B. Campello, Jörg Sander
Venue: Conference KDD 2013
Year: 2013

Outlier detection and ensemble learning are well established research directions in data mining yet the application of ensemble techniques to outlier detection has been rarely studied. Here, we propose and study subsampling as a technique to induce diversity among individual outlier detectors. We show analytically and experimentally that an outlier detector based on a subsample per se, besides inducing diversity, can, under certain conditions, already improve upon the results of the same outlier detector on the complete dataset. Building an ensemble on top of several subsamples is further improving the results. While in the literature so far the intuition that ensembles improve over single outlier detectors has just been transferred from the classification literature, here we also justify analytically why ensembles are also expected to work in the unsupervised area of outlier detection. As a side effect, running an ensemble of several outlier detectors on subsamples of the dataset is more efficient than ensembles based on other means of introducing diversity and, depending on the sample rate and the size of the ensemble, can be even more efficient than just the single outlier detector on the complete data.
Litegt: Efficient and lightweight graph transformers
Authors: Cong Chen, Chaofan Tao, Ngai Wong
Venue: Conference CIKM 2021
Year: 2021

Transformers have shown great potential for modeling long-term dependencies for natural language processing and computer vision. However, little study has applied transformers to graphs, which is challenging due to the poor scalability of the attention mechanism and the under-exploration of graph inductive bias. To bridge this gap, we propose a Lite Graph Transformer (LiteGT) that learns on arbitrary graphs efficiently. First, a node sampling strategy is proposed to sparsify the considered nodes in self-attention with only O (Nlog N) time. Second, we devise two kernelization approaches to form two-branch attention blocks, which not only leverage graph-specific topology information, but also reduce computation further to O (1 over 2 Nlog N). Third, the nodes are updated with different attention schemes during training, thus largely mitigating over-smoothing problems when the model layers deepen. Extensive experiments demonstrate that LiteGT achieves competitive performance on both node classification and link prediction on datasets with millions of nodes. Specifically, Jaccard + Sampling + Dim. reducing setting reduces more than 100x computation and halves the model size without performance degradation.
Inferring the demographics of search users: Social data meets search queries
Authors: Bin Bi, Milad Shokouhi, Michal Kosinski, Thore Graepel
Venue: Conference WWW 2013
Year: 2013

Knowing users' views and demographic traits offers a great potential for personalizing web search results or related services such as query suggestion and query completion. Such signals however are often only available for a small fraction of search users, namely those who log in with their social network account and allow its use for personalization of search results. In this paper, we offer a solution to this problem by showing how user demographic traits such as age and gender, and even political and religious views can be efficiently and accurately inferred based on their search query histories. This is accomplished in two steps; we first train predictive models based on the publically available myPersonality dataset containing users' Facebook Likes and their demographic information. We then match Facebook Likes with search queries using Open Directory Project categories. Finally, we apply the model trained on Facebook Likes to large-scale query logs of a commercial search engine while explicitly taking into account the difference between the traits distribution in both datasets. We find that the accuracy of classifying age and gender, expressed by the area under the ROC curve (AUC), are 77% and 84% respectively for predictions based on Facebook Likes, and only degrade to 74% and 80% when based on search queries. On a US state-by-state basis we find a Pearson correlation of 0.72 for political views between the predicted scores and Gallup data, and 0.54 for affiliation with Judaism between predicted scores and data from the US Religious Landscape Survey. We conclude that it is indeed feasible to infer important demographic data of users from their query history based on labelled Likes data and believe that this approach could provide valuable information for personalization and monetization even in the absence of demographic data.