OpenRaiser/Intern-Atlas huggingface dataset:
Trend: Temporal event and node dynamics for graph representation learning
Authors: Zhihao Wen, Yuan Fang
Venue: Conference WWW 2022
Year: 2022

Temporal graph representation learning has drawn significant attention for the prevalence of temporal graphs in the real world. However, most existing works resort to taking discrete snapshots of the temporal graph, or are not inductive to deal with new nodes, or do not model the exciting effects which is the ability of events to influence the occurrence of another event. In this work, We propose TREND, a novel framework for temporal graph representation learning, driven by TempoRal Event and Node Dynamics and built upon a Hawkes process-based graph neural network (GNN). TREND presents a few major advantages: (1) it is inductive due to its GNN architecture; (2) it captures the exciting effects between events by the adoption of the Hawkes process; (3) as our main novelty, it captures the individual and collective characteristics of events by integrating both event and node dynamics, driving a more precise modeling of the temporal process. Extensive experiments on four real-world datasets demonstrate the effectiveness of our proposed model.
A trainable optimal transport embedding for feature aggregation and its relationship to attention
Authors: Grégoire Mialon, Dexiong Chen, Alexandre d&apos, Aspremont, Julien Mairal
Venue: Conference ICLR 2021
Year: 2021

We address the problem of learning on sets of features, motivated by the need of performing pooling operations in long biological sequences of varying sizes, with long-range dependencies, and possibly few labeled data. To address this challenging task, we introduce a parametrized representation of fixed size, which embeds and then aggregates elements from a given input set according to the optimal transport plan between the set and a trainable reference. Our approach scales to large datasets and allows end-to-end training of the reference, while also providing a simple unsupervised learning mechanism with small computational cost. Our aggregation technique admits two useful interpretations: it may be seen as a mechanism related to attention layers in neural networks, or it may be seen as a scalable surrogate of a classical optimal transport-based kernel. We experimentally demonstrate the effectiveness of our approach on biological sequences, achieving state-of-the-art results for protein fold recognition and detection of chromatin profiles tasks, and, as a proof of concept, we show promising results for processing natural language sequences. We provide an open-source implementation of our embedding that can be used alone or as a module in larger learning models at https://github.com/claying/OTK.
NetProbe: A Fast and Scalable System for Fraud Detection in Online Auction Networks
Authors: Shashank Pandit, Duen Horng Chau, Samuel Wang, Christos Faloutsos
Venue: Conference WWW 2007
Year: 2007

Given a large online network of online auction users and their histories of transactions, how can we spot anomalies and auction fraud? This paper describes the design and implementation of NetProbe, a system that we propose for solving this problem. NetProbe models auction users and transactions as a Markov Random Field tuned to detect the suspicious patterns that fraudsters create, and employs a Belief Propagation mechanism to detect likely fraudsters. Our experiments show that NetProbe is both efficient and effective for fraud detection. We report experiments on synthetic graphs with as many as 7,000 nodes and 30,000 edges, where NetProbe was able to spot fraudulent nodes with over 90% precision and recall, within a matter of seconds. We also report experiments on a real dataset crawled from eBay, with nearly 700,000 transactions between more than 66,000users, where NetProbe was highly effective at unearthing hidden networks of fraudsters, within a realistic response time of about 6 minutes. For scenarios where the underlying data is dynamic in nature, we propose IncrementalNetProbe, which is an approximate, but fast, variant of NetProbe. Our experiments prove that Incremental NetProbe executes nearly doubly fast as compared to NetProbe, while retaining over 99% of its accuracy.
Measuring user satisfaction on smart speaker intelligent assistants using intent sensitive query embeddings
Authors: Seyyed Hadi Hashemi, Kyle Williams, Ahmed El Kholy, Imed Zitouni, Paul A. Crook
Venue: Conference CIKM 2018
Year: 2018

Intelligent assistants are increasingly being used on smart speaker devices, such as Amazon Echo, Google Home, Apple Homepod, and Harmon Kardon Invoke with Cortana. Typically, user satisfaction measurement relies on user interaction signals, such as clicks and scroll movements, in order to determine if a user was satisfied. However, these signals do not exist for smart speakers, which creates a challenge for user satisfaction evaluation on these devices. In this paper, we propose a new signal, user intent, as a means to measure user satisfaction. We propose to use this signal to model user satisfaction in two ways: 1) by developing intent sensitive word embeddings and then using sequences of these intent sensitive query representations to measure user satisfaction; 2) by representing a user's interactions with a smart speaker as a sequence of user intents and thus using this sequence to identify user satisfaction. Our experimental results indicate that our proposed user satisfaction models based on the intent-sensitive query representations have statistically significant improvements over several baselines in terms of common classification evaluation metrics. In particular, our proposed task satisfaction prediction model based on intent-sensitive word embeddings has a 11.81% improvement over a generative model baseline and 6.63% improvement over a user satisfaction prediction model based on Skip-gram word embeddings in terms of the F1 metric. Our findings have implications for the evaluation of Intelligent Assistant systems.
Long horizon forecasting with temporal point processes
Authors: Prathamesh Deshpande, Kamlesh Marathe, Abir De, Sunita Sarawagi
Venue: Conference WSDM 2021
Year: 2021

In recent years, marked temporal point processes (MTPPs) have emerged as a powerful modeling machinery to characterize asynchronous events in a wide variety of applications. MTPPs have demonstrated significant potential in predicting event-timings, especially for events arriving in near future. However, due to current design choices, MTPPs often show poor predictive performance at forecasting event arrivals in distant future. To ameliorate this limitation, in this paper, we design DualTPP which is specifically well-suited to long horizon event forecasting. DualTPP has two components. The first component is an intensity free MTPP model, which captures microscopic event dynamics by modeling the time of future events. The second component takes a different dual perspective of modeling aggregated counts of events in a given time-window, thus encapsulating macroscopic event dynamics. Then we develop a novel inference framework jointly over the two models by solving a sequence of constrained quadratic optimization problems. Experiments with a diverse set of real datasets show that DualTPP outperforms existing MTPP methods on long horizon forecasting by substantial margins, achieving almost an order of magnitude reduction in Wasserstein distance between actual events and forecasts. The code and the datasets can be found at the following URL: https://github.com/pratham16cse/DualTPP
Identifying coordinated accounts on social media through hidden influence and group behaviours
Authors: Karishma Sharma, Yizhou Zhang, Emilio Ferrara, Yan Liu
Venue: Conference KDD 2021
Year: 2021

Disinformation campaigns on social media, involving coordinated activities from malicious accounts towards manipulating public opinion, have become increasingly prevalent. Existing approaches to detect coordinated accounts either make very strict assumptions about coordinated behaviours, or require part of the malicious accounts in the coordinated group to be revealed in order to detect the rest. To address these drawbacks, we propose a generative model, AMDN-HAGE (Attentive Mixture Density Network with Hidden Account Group Estimation) which jointly models account activities and hidden group behaviours based on Temporal Point Processes (TPP) and Gaussian Mixture Model (GMM), to capture inherent characteristics of coordination which is, accounts that coordinate must strongly influence each other's activities, and collectively appear anomalous from normal accounts. To address the challenges of optimizing the proposed model, we provide a bilevel optimization algorithm with theoretical guarantee on convergence. We verified the effectiveness of the proposed method and training algorithm on real-world social network data collected from Twitter related to coordinated campaigns from Russia's Internet Research Agency targeting the 2016 U.S. Presidential Elections, and to identify coordinated campaigns related to the COVID-19 pandemic. Leveraging the learned model, we find that the average influence between coordinated account pairs is the highest. On COVID-19, we found coordinated group spreading anti-vaccination, anti-masks conspiracies that suggest the pandemic is a hoax and political scam.
Intensity-free learning of temporal point processes
Authors: Oleksandr Shchur, Marin Bilos, Stephan Günnemann
Venue: Conference ICLR 2020
Year: 2020

Temporal point processes are the dominant paradigm for modeling sequences of events happening at irregular intervals. The standard way of learning in such models is by estimating the conditional intensity function. However, parameterizing the intensity function usually incurs several trade-offs. We show how to overcome the limitations of intensity-based approaches by directly modeling the conditional distribution of inter-event times. We draw on the literature on normalizing flows to design models that are flexible and efficient. We additionally propose a simple mixture model that matches the flexibility of flow-based models, but also permits sampling and computing moments in closed form. The proposed models achieve state-of-the-art performance in standard prediction tasks and are suitable for novel applications, such as learning sequence embeddings and imputing missing data.
Adversarial training model unifying feature driven and point process perspectives for event popularity prediction
Authors: Qitian Wu, Chaoqi Yang, Hengrui Zhang, Xiaofeng Gao, Paul Weng, Guihai Chen
Venue: Conference CIKM 2018
Year: 2018

This paper targets a general popularity prediction problem for event sequence, which has recently gained great attention due to its extensive applications in various domains. Feature driven method and point process method are two basic thinking paradigms to tackle the prediction problem, but both of them suffer from limitations. In this paper, we propose PreNets unifying the two thinking paradigms in an adversarial manner. On one side, feature driven model acts like a 'critic' who aims to discriminate the predicted popularity from the real one based on a set of temporal features from the sequence. On the other side, point process model acts like an 'interpreter' who recognizes the dynamic patterns in sequence to generate a predicted popularity that can fool the 'critic'. Through a Wasserstein learning based two-player game, the training loss of the 'critic' guides the 'interpreter' to better exploit the sequence patterns and enhance prediction, while the 'interpreter' pushes the 'critic' to select effective early features that helps discrimination. This mechanism enables the framework to absorb the advantages of both feature driven and point process methods. Empirical results show that PreNets achieves significant MAPE improvement for both Twitter cascade and Amazon review prediction.
AntOpt: A Multi-functional Large-scale Decision Optimization Platform
Authors: Jun Zhou, Yang Bao, Hua Wu, Zhigang Hua
Venue: Conference CIKM 2021
Year: 2021

The orderly operation and development of any system are indivisible from decision optimization. Several issues in life are applicable to the thought of optimization problems to resolve. In this digital age, the size of information and data is obtaining larger and the potency of problem determination is changing into more demanding. Though there're many solvers for specific optimization problems, in the face of large-scale scenarios, there's no single platform that concurrently addresses usability, solvers' uniformity, and computing efficiency. In this demo, we present AntOpt, a decision optimization platform that integrates large-scale distributed computing engines, optimization algorithm solvers and productized services.
Neural attentional rating regression with review-level explanations
Authors: Chong Chen, Min Zhang, Yiqun Liu, Shaoping Ma
Venue: Conference WWW 2018
Year: 2018

Reviews information is dominant for users to make online purchasing decisions in e-commerces. However, the usefulness of reviews is varied. We argue that less-useful reviews hurt model's performance, and are also less meaningful for user's reference. While some existing models utilize reviews for improving the performance of recommender systems, few of them consider the usefulness of reviews for recommendation quality. In this paper, we introduce a novel attention mechanism to explore the usefulness of reviews, and propose a Neural Attentional Regression model with Review-level Explanations (NARRE) for recommendation. Specifically, NARRE can not only predict precise ratings, but also learn the usefulness of each review simultaneously. Therefore, the highly-useful reviews are obtained which provide review-level explanations to help users make better and faster decisions. Extensive experiments on benchmark datasets of Amazon and Yelp on different domains show that the proposed NARRE model consistently outperforms the state-of-the-art recommendation approaches, including PMF, NMF, SVD++, HFT, and DeepCoNN in terms of rating prediction, by the proposed attention model that takes review usefulness into consideration. Furthermore, the selected reviews are shown to be effective when taking existing review-usefulness ratings in the system as ground truth. Besides, crowd-sourcing based evaluations reveal that in most cases, NARRE achieves equal or even better performances than system's usefulness rating method in selecting reviews. And it is flexible to offer great help on the dominant cases in real e-commerce scenarios when the ratings on review-usefulness are not available in the system.
Disentangling Preference Representations for Recommendation Critiquing with ß-VAE
Authors: Preksha Nema, Alexandros Karatzoglou, Filip Radlinski
Venue: Conference CIKM 2021
Year: 2021

Modern recommender systems usually embed users and items into a learned vector space representation. Similarity in this space is used to generate recommendations, and recommendation methods are agnostic to the structure of the embedding space. Motivated by the need for recommendation systems to be more transparent and controllable, we postulate that it is beneficial to assign meaning to some of the dimensions of user and item representations. Disentanglement is one technique commonly used for this purpose. We presenta novel supervised disentangling approach for recommendation tasks. Our model learns embeddings where attributes of interest are disentangled, while requiring only a very small number of labeled items at training time. The model can then generate interactive and critiquable recommendations for all users, without requiring any labels at recommendation time, and without sacrificing any recommendation performance. Our approach thus provides users with levers to manipulate, critique and fine-tune recommendations, and gives insight into why particular recommendations are made. Given only user-item interactions at recommendation time, we show that it identifies user tastes with respect to the attributes that have been disentangled, allowing for users to manipulate recommendations across these attributes.
WG4Rec: Modeling Textual Content with Word Graph for News Recommendation
Authors: Shaoyun Shi, Weizhi Ma, Zhen Wang, Min Zhang, Kun Fang, Jingfang Xu, Yiqun Liu, Shaoping Ma
Venue: Conference CIKM 2021
Year: 2021

News recommendation plays an indispensable role in acquiring daily news for users. Previous studies make great efforts to model high-order feature interactions between users and items, where various neural models are applied (e.g., RNN, GNN). However, we find that seldom efforts are made to get better representations for news. Most previous methods simply adopt pre-trained word embeddings to represent news and also suffer from cold-start users. In this work, we propose a new textual content representation method by building a word graph for recommendation, which is named WG4Rec. Three types of word associations are adopted in WG4Rec for content representation and user preference modeling, namely: 1)semantically-similar according to pre-trained word vectors, 2)co-occurrence in documents, and 3)co-click by users across documents. As extra information can be unified by adding nodes/edges to the word graph easily, WG4Rec is flexible to make use of cross-platform and cross-domain context for recommendation to alleviate the cold-start issue. To the best of our knowledge, it is the first attempt that using these relationships for news recommendation to better model textual content and adopt cross-platform information. Experimental results on two large-scale real-world datasets show that WG4Rec significantly outperforms state-of-the-art algorithms, especially for cold users in the online environment. Besides, WG4Rec achieves better performances when cross-platform information is utilized.
Learning to transfer graph embeddings for inductive graph based recommendation
Authors: Le Wu, Yonghui Yang 0001, Lei Chen 0051, Defu Lian, Richang Hong, Meng Wang 0001
Venue: Conference SIGIR 2020
Year: 2020

With the increasing availability of videos, how to edit them and present the most interesting parts to users, i.e., video highlight, has become an urgent need with many broad applications. As users' visual preferences are subjective and vary from person to person, previous generalized video highlight extraction models fail to tailor to users' unique preferences. In this paper, we study the problem of personalized video highlight recommendation with rich visual content. By dividing each video into non-overlapping segments, we formulate the problem as a personalized segment recommendation task with many new segments in the test stage. The key challenges of this problem lie in: the cold-start users with limited video highlight records in the training data and new segments without any user ratings at the test stage. To tackle these challenges, an intuitive idea is to formulate a user-item interaction graph and perform inductive graph neural network based models for better user and item embedding learning. However, the graph embedding models fail to generalize to unseen items as these models rely on the item content feature and item link information for item embedding calculation. To this end, we propose an inductive Graph based Transfer learning framework for personalized video highlight Recommendation (TransGRec). TransGRec is composed of two parts: a graph neural network followed by an item embedding transfer network. Specifically, the graph neural network part exploits the higher-order proximity between users and segments to alleviate the user cold-start problem. The transfer network is designed to approximate the learned item embeddings from graph neural networks by taking each item's visual content as input, in order to tackle the new segment problem in the test phase. We design two detailed implementations of the transfer learning optimization function, and we show how the two parts of TransGRec can be efficiently optimized with different transfer learning optimization functions. Please note that, our proposed framework is generally applicable to any inductive graph based recommendation model to address the new node problem without any link structure. Finally, extensive experimental results on a real-world dataset clearly show the effectiveness of our proposed model.
Counterfactual review-based recommendation
Authors: Kun Xiong, Wenwen Ye, Xu Chen, Yongfeng Zhang, Wayne Xin Zhao, Binbin Hu, Zhiqiang Zhang, Jun Zhou
Venue: Conference CIKM 2021
Year: 2021

Incorporating review information into the recommender system has been demonstrated to be an effective method for boosting the recommendation performance. Previous research mainly focus on designing advanced architectures to better profile the users and items. However, the review information in realities can be highly sparse and imbalanced, which poses great challenges for effective user/item representations and satisfied performance enhancement. To alleviate this problem, in this paper, we propose to improve review-based recommendation by counterfactually augmenting the training samples. We focus on a common setting --- feature-aware recommendation, and the main building block of our idea lies in the counterfactual question: "what would be the user's decision if her feature-level preference had been different?''. When augmenting the training samples, we actively change the user preference (also called intervention), and predict the user feedback on the items based on pre-trained recommender models. Instead of changing the user preference in a random manner, we design a learning-based method to discover the samples which are more effective for model optimization. In order to improve the sample qualities, we propose two strategies --- constrained feature perturbation and frequency-based sampling --- to equip our model. Since the sample generation model can be not perfect, we theoretically analyze the relation between the model prediction error and the number of generated samples. As a byproduct, our framework can explain the user pair-wise preference, which is complementary to the traditional point-wise explanations. Extensive experiments demonstrate that our model can significantly improve the performance of the state-of-the-art methods.
FiShNet: Fine-Grained Filter Sharing for Resource-Efficient Multi-Task Learning
Authors: Xin Dai, Xiangnan Kong, Tian Guo, Xinlu He
Venue: Conference CIKM 2021
Year: 2021

Multi-task learning has attracted much attention in recent years, where the goal is to learn multiple tasks by exploiting the similarities and differences between the tasks. Previous researches on multi-task learning mainly focus on flexible methods for feature sharing (e.g., soft sharing) under resource-sufficient settings (e.g., on GPU servers). However, in many real-world applications, we often need to deploy multi-task learning models on resource-constrained platforms (e.g., mobile devices). The high resource requirement of soft-sharing methods can make them hard to deploy on mobile devices. In this paper, we study the problem of Resource-efficient Multi-Task Learning (MTL), where the goal is to design a resource-friendly model that suits resource-constrained inference environment, e.g., security camera or mobile devices. We formulate the Resource-efficient MTL problem as a fine-grained filter sharing problem, i.e., learning how to share filters at any given convolutional layers among multiple tasks. We proposed a novel solution for parameter sharing, called FiShNet. Different from soft-sharing approaches, where the computational cost per task is growing w.r.t. the number of other tasks, FiShNet can achieve high accuracy comparable to soft-sharing approaches, while only consuming a constant computational cost per task. Different from hard-sharing approaches, where the parameter sharing structures are hand-picked, FiShNet can learn how to share parameters directly on the training data with finer-grained sharing. We evaluate FiShNet on a number of problem settings and datasets for multi-task learning. We show that FiShNet achieves high accuracy when compared with state-of-the-art methods in multi-task learning, while only requiring a fraction of the computational resource.