OpenRaiser/Intern-Atlas huggingface dataset:
A request-level guaranteed delivery advertising planning: Forecasting and allocation
Authors: Hong Zhang, Lan Zhang 0002, Lan Xu 0001, Xiaoyang Ma, Zhengtao Wu, Cong Tang, Wei Xu, Yiguo Yang
Venue: Conference KDD 2020
Year: 2020

The guaranteed delivery model is widely used in online advertising. The publisher sells impressions in advance by promising to serve each advertiser an agreed-upon number of target impressions that satisfy specific attribute requirements over a fixed time period. Previous efforts usually model the service as a crowd-level or user-level supply allocation problem and focus on searching optimal allocation for online serving, assuming that forecasts of supply are available and contracts are already signed. Existing techniques are not sufficient to meet the needs of today's industry trends: 1) advertisers pursue more precise targeting, which requires not only user-level attributes but also request-level attributes; 2) users prefer more friendly ad serving, which imposes more diverse serving constraints; 3) the bottleneck of the publisher's revenue growth lies in not only the ad serving, but also the forecast accuracy and sales strategy. These issues are non-trivial to address, since the scale of the request-level model is orders of magnitude larger than that of the crowd-level or user-level models. Facing the challenges, we present a holistic design of a request-level guaranteed delivery advertising planning system with careful optimization for all three critical components including impression forecasting, selling and serving. Our system has been deployed in the Tencent online guaranteed delivery advertising system serving billion level users for nearly one year. Evaluations on large-scale real data and the performance of the deployed system both demonstrate that our design can significantly increase the request-level impression forecast accuracy and delivery rate.
Temporal phenotyping from longitudinal electronic health records: A graph based framework
Authors: Chuanren Liu, Fei Wang, Jianying Hu, Hui Xiong
Venue: Conference KDD 2015
Year: 2015

The rapid growth in the development of healthcare information systems has led to an increased interest in utilizing the patient Electronic Health Records (EHR) for assisting disease diagnosis and phenotyping. The patient EHRs are generally longitudinal and naturally represented as medical event sequences, where the events include clinical notes, problems, medications, vital signs, laboratory reports, etc. The longitudinal and heterogeneous properties make EHR analysis an inherently difficult challenge. To address this challenge, in this paper, we develop a novel representation, namely the temporal graph, for such event sequences. The temporal graph is informative for a variety of challenging analytic tasks, such as predictive modeling, since it can capture temporal relationships of the medical events in each event sequence. By summarizing the longitudinal data, the temporal graphs are also robust and resistant to noisy and irregular observations. Based on the temporal graph representation, we further develop an approach for temporal phenotyping to identify the most significant and interpretable graph basis as phenotypes. This helps us better understand the disease evolving patterns. Moreover, by expressing the temporal graphs with the phenotypes, the expressing coefficients can be used for applications such as personalized medicine, disease diagnosis, and patient segmentation. Our temporal phenotyping framework is also flexible to incorporate semi-supervised/supervised information. Finally, we validate our framework on two real-world tasks. One is predicting the onset risk of heart failure. Another is predicting the risk of heart failure related hospitalization for patients with COPD pre-condition. Our results show that the diagnosis performance in both tasks can be improved significantly by the proposed approaches. Also, we illustrate some interesting phenotypes derived from the data.
Projective Ranking: A Transferable Evasion Attack Method on Graph Neural Networks
Authors: He Zhang, Bang Wu, Xiangwen Yang, Chuan Zhou, Shuo Wang, Xingliang Yuan, Shirui Pan
Venue: Conference CIKM 2021
Year: 2021

Graph Neural Networks (GNNs) have emerged as a series of effective learning methods for graph-related tasks. However, GNNs are shown vulnerable to adversarial attacks, where attackers can fool GNNs into making wrong predictions on adversarial samples with well-designed perturbations. Specifically, we observe that the current evasion attacks suffer from two limitations: (1) the attack strategy based on the reinforcement learning method might not be transferable when the attack budget changes; (2) the greedy mechanism in the vanilla gradient-based method ignores the long-term benefits of each perturbation operation. In this paper, we propose a new attack method named projective ranking to overcome the above limitations. Our idea is to learn a powerful attack strategy considering the long-term benefits of perturbations, then adjust it as little as possible to generate adversarial samples under different budgets. We further employ mutual information to measure the long-term benefits of each perturbation and rank them accordingly, so the learned attack strategy has better attack performance. Our method dramatically reduces the adaptation cost of learning a new attack strategy by projecting the attack strategy when the attack budget changes. Our preliminary evaluation results in synthesized and real-world datasets demonstrate that our method owns powerful attack performance and effective transferability.
Learning to Recommend Accurate and Diverse Items
Authors: Peizhe Cheng, Shuaiqiang Wang, Jun Ma, Jiankai Sun, Hui Xiong
Venue: Conference WWW 2017
Year: 2017

In this study, we investigate diversified recommendation problem by supervised learning, seeking significant improvement in diversity while maintaining accuracy. In particular, we regard each user as a training instance, and heuristically choose a subset of accurate and diverse items as ground-truth for each user. We then represent each user or item as a vector resulted from the factorization of the user-item rating matrix. In our paper, we try to discover a factorization for matching the following supervised learning task. In doing this, we define two coupled optimization problems, parameterized matrix factorization and structural learning, to formulate our task. And we propose a diversified collaborative filtering algorithm (DCF) to solve the coupled problems. We also introduce a new pairwise accuracy metric and a normalized topic coverage diversity metric to measure the performance of accuracy and diversity respectively. Extensive experiments on benchmark datasets show the performance gains of DCF in comparison with the state-of-the-art algorithms.
Spectral relaxations and fair densest subgraphs
Authors: Aris Anagnostopoulos, Luca Becchetti, Adriano Fazzone, Cristina Menghini, Chris Schwiegelshohn
Venue: Conference CIKM 2020
Year: 2020

Reducing hidden bias in the data and ensuring fairness in algorithmic data analysis has recently received significant attention. In this paper, we address the problem of identifying a densest subgraph, while ensuring that none of one binary protected attribute is disparately impacted. Unfortunately, the underlying algorithmic problem is NP-hard, even in its approximation version: approximating the densest fair subgraph with a polynomial-time algorithm is at least as hard as the densest subgraph problem of at most k vertices, for which no constant approximation algorithms are known. Despite such negative premises, we are able to provide approximation results in two important cases. In particular, we are able to prove that a suitable spectral embedding allows recovery of an almost optimal, fair, dense subgraph hidden in the input data, whenever one is present, a result that is further supported by experimental evidence. We also show a polynomial-time, $2$-approximation algorithm, whenever the underlying graph is itself fair. We finally prove that, under the small set expansion hypothesis, this result is tight for fair graphs. The above theoretical findings drive the design of heuristics, which we experimentally evaluate on a scenario based on real data, in which our aim is to strike a good balance between diversity and highly correlated items from Amazon co-purchasing graphs.
The importance of pessimism in fixed-dataset policy optimization
Authors: Jacob Buckman, Carles Gelada, Marc G. Bellemare
Venue: Conference ICLR 2021
Year: 2021

We study worst-case guarantees on the expected return of fixed-dataset policy optimization algorithms. Our core contribution is a unified conceptual and mathematical framework for the study of algorithms in this regime. This analysis reveals that for naive approaches, the possibility of erroneous value overestimation leads to a difficult-to-satisfy requirement: in order to guarantee that we select a policy which is near-optimal, we may need the dataset to be informative of the value of every policy. To avoid this, algorithms can follow the pessimism principle, which states that we should choose the policy which acts optimally in the worst possible world. We show why pessimistic algorithms can achieve good performance even when the dataset is not informative of every policy, and derive families of algorithms which follow this principle. These theoretical findings are validated by experiments on a tabular gridworld, and deep learning experiments on four MinAtar environments.
Karate Club: An API Oriented Open-source Python Framework for Unsupervised Learning on Graphs
Authors: Benedek Rozemberczki, Oliver Kiss, Rik Sarkar
Venue: Conference CIKM 2020
Year: 2020

Graphs encode important structural properties of complex systems. Machine learning on graphs has therefore emerged as an important technique in research and applications. We present Karate Club - a Python framework combining more than 30 state-of-the-art graph mining algorithms. These unsupervised techniques make it easy to identify and represent common graph features. The primary goal of the package is to make community detection, node and whole graph embedding available to a wide audience of machine learning researchers and practitioners. Karate Club is designed with an emphasis on a consistent application interface, scalability, ease of use, sensible out of the box model behaviour, standardized dataset ingestion, and output generation. This paper discusses the design principles behind the framework with practical examples. We show Karate Club's efficiency in learning performance on a wide range of real world clustering problems and classification tasks along with supporting evidence of its competitive speed.
Frequency-based search-control in dyna
Authors: Yangchen Pan, Jincheng Mei, Amir-massoud Farahmand
Venue: Conference ICLR 2020
Year: 2020

Model-based reinforcement learning has been empirically demonstrated as a successful strategy to improve sample efficiency. In particular, Dyna is an elegant model-based architecture integrating learning and planning that provides huge flexibility of using a model. One of the most important components in Dyna is called search-control, which refers to the process of generating state or state-action pairs from which we query the model to acquire simulated experiences. Search-control is critical in improving learning efficiency. In this work, we propose a simple and novel search-control strategy by searching high frequency regions of the value function. Our main intuition is built on Shannon sampling theorem from signal processing, which indicates that a high frequency signal requires more samples to reconstruct. We empirically show that a high frequency function is more difficult to approximate. This suggests a search-control strategy: we should use states from high frequency regions of the value function to query the model to acquire more samples. We develop a simple strategy to locally measure the frequency of a function by gradient and hessian norms, and provide theoretical justification for this approach. We then apply our strategy to search-control in Dyna, and conduct experiments to show its property and effectiveness on benchmark domains.
Online algorithms with multiple predictions
Authors: Keerti Anand, Rong Ge 0001, Amit Kumar 0001, Debmalya Panigrahi
Venue: Conference ICML 2022
Year: 2022

This paper studies online algorithms augmented with multiple machine-learned predictions. While online algorithms augmented with a single prediction have been extensively studied in recent years, the literature for the multiple predictions setting is sparse. In this paper, we give a generic algorithmic framework for online covering problems with multiple predictions that obtains an online solution that is competitive against the performance of the best predictor. Our algorithm incorporates the use of predictions in the classic potential-based analysis of online algorithms. We apply our algorithmic framework to solve classical problems such as online set cover, (weighted) caching, and online facility location in the multiple predictions setting. Our algorithm can also be robustified, i.e., the algorithm can be simultaneously made competitive against the best prediction and the performance of the best online algorithm (without prediction).
Releasing search queries and clicks privately
Authors: Aleksandra Korolova, Krishnaram Kenthapadi, Nina Mishra, Alexandros Ntoulas
Venue: Conference WWW 2009
Year: 2009

The question of how to publish an anonymized search log was brought to the forefront by a well-intentioned, but privacy-unaware AOL search log release. Since then a series of ad-hoc techniques have been proposed in the literature, though none are known to be provably private. In this paper, we take a major step towards a solution: we show how queries, clicks and their associated perturbed counts can be published in a manner that rigorously preserves privacy. Our algorithm is decidedly simple to state, but non-trivial to analyze. On the opposite side of privacy is the question of whether the data we can safely publish is of any use. Our findings offer a glimmer of hope: we demonstrate that a non-negligible fraction of queries and clicks can indeed be safely published via a collection of experiments on a real search log. In addition, we select an application, keyword generation, and show that the keyword suggestions generated from the perturbed data resemble those generated from the original data.
Availability attacks create shortcuts
Authors: Da Yu, Huishuai Zhang, Wei Chen 0034, Jian Yin 0001, Tie-Yan Liu
Venue: Conference KDD 2022
Year: 2022

Availability attacks, which poison the training data with imperceptible perturbations, can make the data \emph{not exploitable} by machine learning algorithms so as to prevent unauthorized use of data. In this work, we investigate why these perturbations work in principle. We are the first to unveil an important population property of the perturbations of these attacks: they are almost \textbf{linearly separable} when assigned with the target labels of the corresponding samples, which hence can work as \emph{shortcuts} for the learning objective. We further verify that linear separability is indeed the workhorse for availability attacks. We synthesize linearly-separable perturbations as attacks and show that they are as powerful as the deliberately crafted attacks. Moreover, such synthetic perturbations are much easier to generate. For example, previous attacks need dozens of hours to generate perturbations for ImageNet while our algorithm only needs several seconds. Our finding also suggests that the \emph{shortcut learning} is more widely present than previously believed as deep models would rely on shortcuts even if they are of an imperceptible scale and mixed together with the normal features. Our source code is published at \url{https://github.com/dayu11/Availability-Attacks-Create-Shortcuts}.
The variational bandwidth bottleneck: Stochastic evaluation on an information budget
Authors: Anirudh Goyal, Yoshua Bengio, Matthew M. Botvinick, Sergey Levine
Venue: Conference ICLR 2020
Year: 2020

In many applications, it is desirable to extract only the relevant information from complex input data, which involves making a decision about which input features are relevant. The information bottleneck method formalizes this as an information-theoretic optimization problem by maintaining an optimal tradeoff between compression (throwing away irrelevant input information), and predicting the target. In many problem settings, including the reinforcement learning problems we consider in this work, we might prefer to compress only part of the input. This is typically the case when we have a standard conditioning input, such as a state observation, and a "privileged" input, which might correspond to the goal of a task, the output of a costly planning algorithm, or communication with another agent. In such cases, we might prefer to compress the privileged input, either to achieve better generalization (e.g., with respect to goals) or to minimize access to costly information (e.g., in the case of communication). Practical implementations of the information bottleneck based on variational inference require access to the privileged input in order to compute the bottleneck variable, so although they perform compression, this compression operation itself needs unrestricted, lossless access. In this work, we propose the variational bandwidth bottleneck, which decides for each example on the estimated value of the privileged information before seeing it, i.e., only based on the standard input, and then accordingly chooses stochastically, whether to access the privileged input or not. We formulate a tractable approximation to this framework and demonstrate in a series of reinforcement learning experiments that it can improve generalization and reduce access to computationally costly information.
Order learning and its application to age estimation
Authors: Kyungsun Lim, Nyeong-Ho Shin, Young-Yoon Lee, Chang-Su Kim 0001
Venue: Conference ICLR 2020
Year: 2020

We propose order learning to determine the order graph of classes, representing ranks or priorities, and classify an object instance into one of the classes. To this end, we design a pairwise comparator to categorize the relationship between two instances into one of three cases: one instance is `greater than,' `similar to,' or `smaller than' the other. Then, by comparing an input instance with reference instances and maximizing the consistency among the comparison results, the class of the input can be estimated reliably. We apply order learning to develop a facial age estimator, which provides the state-of-the-art performance. Moreover, the performance is further improved when the order graph is divided into disjoint chains using gender and ethnic group information or even in an unsupervised manner.
Modeling heart rate and activity data for personalized fitness recommendation
Authors: Jianmo Ni, Larry Muhlstein, Julian J. McAuley
Venue: Conference WWW 2019
Year: 2019

Activity logs collected from wearable devices (e.g. Apple Watch, Fitbit, etc.) are a promising source of data to facilitate a wide range of applications such as personalized exercise scheduling, workout recommendation, and heart rate anomaly detection. However, such data are heterogeneous, noisy, diverse in scale and resolution, and have complex interdependencies, making them challenging to model. In this paper, we develop context-aware sequential models to capture the personalized and temporal patterns of fitness data. Specifically, we propose FitRec - an LSTM-based model that captures two levels of context information: context within a specific activity, and context across a user's activity history. We are specifically interested in (a) estimating a user's heart rate profile for a candidate activity; and (b) predicting and recommending suitable activities on this basis. We evaluate our model on a novel dataset containing over 250 thousand workout records coupled with hundreds of millions of parallel sensor measurements (e.g. heart rate, GPS) and metadata. We demonstrate that the model is able to learn contextual, personalized, and activity-specific dynamics of users' heart rate profiles during exercise. We evaluate the proposed model against baselines on several personalized recommendation tasks, showing the promise of using wearable data for activity modeling and recommendation.
Constrained Social Community Recommendation
Authors: Xingyi Zhang 0003, Shuliang Xu, Wenqing Lin, Sibo Wang 0001
Venue: Conference KDD 2023
Year: 2023

In online social networks, users with similar interests tend to come together, forming social communities. Nowadays, user-defined communities become a prominent part of online social platforms as people who have joined such communities tend to be more active in social networks. Therefore, recommending explicit communities to users provides great potential to advance online services.
Unbiased offline evaluation of contextual-bandit-based news article recommendation algorithms
Authors: Lihong Li, Wei Chu, John Langford, Xuanhui Wang
Venue: Conference WSDM 2011
Year: 2011

Contextual bandit algorithms have become popular for online recommendation systems such as Digg, Yahoo! Buzz, and news recommendation in general. Offline evaluation of the effectiveness of new algorithms in these applications is critical for protecting online user experiences but very challenging due to their "partial-label" nature. Common practice is to create a simulator which simulates the online environment for the problem at hand and then run an algorithm against this simulator. However, creating simulator itself is often difficult and modeling bias is usually unavoidably introduced. In this paper, we introduce a replay methodology for contextual bandit algorithm evaluation. Different from simulator-based approaches, our method is completely data-driven and very easy to adapt to different applications. More importantly, our method can provide provably unbiased evaluations. Our empirical results on a large-scale news article recommendation dataset collected from Yahoo! Front Page conform well with our theoretical results. Furthermore, comparisons between our offline replay and online bucket evaluation of several contextual bandit algorithms show accuracy and effectiveness of our offline evaluation method.
Nhp: Neural hypergraph link prediction
Authors: Naganand Yadati, Vikram Nitin, Madhav Nimishakavi, Prateek Yadav, Anand Louis, Partha P. Talukdar
Venue: Conference CIKM 2020
Year: 2020

Link prediction insimple graphs is a fundamental problem in which new links between vertices are predicted based on the observed structure of the graph. However, in many real-world applications, there is a need to model relationships among vertices that go beyond pairwise associations. For example, in a chemical reaction, relationship among the reactants and products is inherently higher-order. Additionally, there is a need to represent the direction from reactants to products. Hypergraphs provide a natural way to represent such complex higher-order relationships. Graph Convolutional Network (GCN) has recently emerged as a powerful deep learning-based approach for link prediction over simple graphs. However, their suitability for link prediction in hypergraphs is underexplored -- we fill this gap in this paper and propose Neural Hyperlink Predictor (NHP). NHP adapts GCNs for link prediction in hypergraphs. We propose two variants of NHP -- NHP-U and NHP-D -- for link prediction over undirected and directed hypergraphs, respectively. To the best of our knowledge, NHP-D is the first-ever method for link prediction over directed hypergraphs. An important feature of NHP is that it can also be used for hyperlinks in which dissimilar vertices interact (e.g. acids reacting with bases). Another attractive feature of NHP is that it can be used to predict unseen hyperlinks at test time (inductive hyperlink prediction). Through extensive experiments on multiple real-world datasets, we show NHP's effectiveness.