OpenRaiser/Intern-Atlas huggingface dataset:
Towards Reliable and Practicable Algorithmic Recourse
Authors: Himabindu Lakkaraju
Venue: CIKM
Year: 2021

As predictive models are increasingly being deployed in high-stakes decision making (e.g., loan approvals), there has been growing interest in developing post hoc techniques which provide recourse to individuals who have been adversely impacted by predicted outcomes. For example, when an individual is denied loan by a predictive model deployed by a bank, they should be informed about reasons for this decision and what can be done to reverse it. While several approaches have been proposed to tackle the problem of generating recourses, these techniques rely heavily on various restrictive assumptions. For instance, these techniques generate recourses under the assumption that the underlying predictive models do not change. In practice, however, models are often updated for a variety of reasons including data distribution shifts. There is little to no research that systematically investigates and addresses these limitations. In this talk, I will discuss some of our recent work that sheds light on and addresses the aforementioned challenges, thereby paving the way for making algorithmic recourse practicable and reliable. First, I will present theoretical and empirical results which demonstrate that the recourses generated by state-of-the-art approaches are often invalidated due to model updates. Next, I will introduce a novel algorithmic framework based on adversarial training to generate recourses that remain valid even if the underlying models are updated. I will conclude the talk by presenting theoretical and empirical evidence for the efficacy of our solutions, and also discussing other open problems in the burgeoning field of algorithmic recourse.
First Workshop on Knowledge Injection in Neural Networks (KINN)
Authors: Vasudev Lal, Somak Aditya, Yezhou Yang, Pasquale Minervini, Sandya Mannarswamy
Venue: CIKM
Year: 2021

Deep learning (DL) has made rapid progress in the last decade, with neural network-based language and vision models achieving state-of-the-art performance in various tasks. Yet purely data-driven neural network models exhibit several issues impacting real-world deployment of such models adversely. These include reliance on large quantities of training data, poor robustness, lack of generalization, poor explainability, and glaring gaps in implicit and commonsense knowledge. The availability of rich structured (or semi-structured) knowledge sources has spurred the research community into exploring Knowledge Injection in Neural Networks (KINN) as a means of mitigating the above-mentioned challenges. This has led to the development of hybrid AI systems that combine the purely data-driven learning of the neural network models with an infusion of knowledge from external sources. Such KINN systems include the development of retrieval augmented neural models, neuro symbolic systems and a plethora of combinations of NNs and knowledge graphs and structured knowledge bases. Given the considerable promise of knowledge injection in overcoming the current challenges associated with purely data driven NN models, we propose a workshop on Knowledge Injection in Neural Networks (KINN) at CIKM 2021. The goal of this workshop is to focus the attention of the CIKM research community on addressing the open challenges in this emerging research area. Given that the CIKM research community has a rich mix of experts in structured knowledge representation, IR and DL, this workshop is intended to facilitate cross-disciplinary collaboration across the various CIKM research communities into building efficient and scalable KINN systems.
Efficient Multi-Scale Feature Generation Adaptive Network
Authors: Gwanghan Lee, Minha Kim, Minha Kim, Simon S. Woo
Venue: CIKM
Year: 2021

Recently, an early exit network, which dynamically adjusts the model complexity during inference time, has achieved remarkable performance and neural network efficiency to be used for various applications. So far, many researchers have been focusing on reducing the redundancy of input sample or model architecture. However, they were unsuccessful at resolving the performance drop of early classifiers that make predictions with insufficient high-level feature information. Consequently, the performance degradation of early classifiers had a devastating effect on the entire network performance sharing the backbone. Thus, in this paper, we propose an Efficient Multi-Scale Feature Generation Adaptive Network (EMGNet), which not only reduced the redundancy of the architecture but also generates multi-scale features to improve the performance of the early exit network. Our approach renders multi-scale feature generation highly efficient through sharing weights in the center of the convolution kernel. Also, our gating network effectively learns to automatically determine the proper multi-scale feature ratio required for each convolution layer in different locations of the network. We demonstrate that our proposed model outperforms the state-of-the-art adaptive networks on CIFAR10, CIFAR100, and ImageNet datasets. The implementation code is available at https://github.com/lee-gwang/EMGNet
CrossAug: A Contrastive Data Augmentation Method for Debiasing Fact Verification Models
Authors: Minwoo Lee, Seungpil Won, Juae Kim, Hwanhee Lee, Cheon-Eum Park, Kyomin Jung
Venue: CIKM
Year: 2021

Fact verification datasets are typically constructed using crowdsourcing techniques due to the lack of text sources with veracity labels. However, the crowdsourcing process often produces undesired biases in data that cause models to learn spurious patterns. In this paper, we propose CrossAug, a contrastive data augmentation method for debiasing fact verification models. Specifically, we employ a two-stage augmentation pipeline to generate new claims and evidences from existing samples. The generated samples are then paired cross-wise with the original pair, forming contrastive samples that facilitate the model to rely less on spurious patterns and learn more robust representations. Experimental results show that our method outperforms the previous state-of-the-art debiasing technique by 3.6% on the debiased extension of the FEVER dataset, with a total performance boost of 10.13% from the baseline. Furthermore, we evaluate our approach in data-scarce settings, where models can be more susceptible to biases due to the lack of training data. Experimental results demonstrate that our approach is also effective at debiasing in these low-resource conditions, exceeding the baseline performance on the Symmetric dataset with just 1% of the original data.
You Are What and Where You Are: Graph Enhanced Attention Network for Explainable POI Recommendation
Authors: Zeyu Li, Wei Cheng, Haiqi Xiao, Wenchao Yu, Haifeng Chen, Wei Wang
Venue: CIKM
Year: 2021

Point-of-interest (POI) recommendation is an emerging area of research on location-based social networks to analyze user behaviors and contextual check-in information. For this problem, existing approaches, with shallow or deep architectures, have two major drawbacks. First, for these approaches, the attributes of individuals have been largely ignored. Therefore, it would be hard, if not impossible, to gather sufficient user attribute features to have complete coverage of possible motivation factors. Second, most existing models preserve the information of users or POIs by latent representations without explicitly highlighting salient factors or signals. Consequently, the trained models with unjustifiable parameters provide few persuasive rationales to explain why users favor or dislike certain POIs and what really causes a visit. To overcome these drawbacks, we propose GEAPR, a POI recommender that is able to interpret the POI prediction in an end-to-end fashion. Specifically, GEAPR learns user representations by aggregating different factors, such as structural context, neighbor impact, user attributes, and geolocation influence. GEAPR takes advantage of a triple attention mechanism to quantify the influences of different factors for each resulting recommendation and performs a thorough analysis of the model interpretability. Extensive experiments on real-world datasets demonstrate the effectiveness of the proposed model. GEAPR is deployed and under test on an internal web server. An example interface is presented to showcase its application on explainable POI recommendation.
RCES: Rapid Cues Exploratory Search Using Taxonomies For COVID-19
Authors: Wei Li, Rishi Choudhary, Arjumand Younus, Bruno Ohana, Nicole Baker, Brendan Leen, Muhammad Atif Qureshi
Venue: CIKM
Year: 2021

To assist the COVID-19 focused researchers in life science and healthcare in understanding the pandemic, we present an exploratory information retrieval system called RCES. The system employs a previously developed EVE (Explainable Vector-based Embedding) model using DBpedia and an adopted model using MeSH taxonomies to exploit concept relations related to COVID-19. Various expansion methods are also developed, along with explanations and facets that collectively form rapid cues for a valuable navigational and informed user experience.
Lightweight Self-Attentive Sequential Recommendation
Authors: Yang Li, Tong Chen, Peng-Fei Zhang, Hongzhi Yin
Venue: CIKM
Year: 2021

Modern deep neural networks (DNNs) have greatly facilitated the development of sequential recommender systems by achieving state-of-the-art recommendation performance on various sequential recommendation tasks. Given a sequence of interacted items, existing DNN-based sequential recommenders commonly embed each item into a unique vector to support subsequent computations of the user interest. However, due to the potentially large number of items, the over-parameterised item embedding matrix of a sequential recommender has become a memory bottleneck for efficient deployment in resource-constrained environments, e.g., smartphones and other edge devices. Furthermore, we observe that the widely-used multi-head self-attention, though being effective in modelling sequential dependencies among items, heavily relies on redundant attention units to fully capture both global and local item-item transition patterns within a sequence. In this paper, we introduce a novel lightweight self-attentive network (LSAN) for sequential recommendation. To aggressively compress the original embedding matrix, LSAN leverages the notion of compositional embeddings, where each item embedding is composed by merging a group of selected base embedding vectors derived from substantially smaller embedding matrices. Meanwhile, to account for the intrinsic dynamics of each item, we further propose a temporal context-aware embedding composition scheme. Besides, we develop an innovative twin-attention network that alleviates the redundancy of the traditional multi-head self-attention while retaining full capacity for capturing long- and short-term (i.e., global and local) item dependencies. Comprehensive experiments demonstrate that LSAN significantly advances the accuracy and memory efficiency of existing sequential recommenders.
Causal-Aware Generative Imputation for Automated Underwriting
Authors: Qian Li, Tri Dung Duong, Zhichao Wang, Shaowu Liu, Dingxian Wang, Guandong Xu
Venue: CIKM
Year: 2021

Underwriting is an important process in insurance and is concerned with accepting individuals into insurance policy with tolerable claim risk. Underwriting is a tedious and labor intensive process relying on underwriters' domain knowledge and experience, thus is labor intensive and prone to error. Machine learning models are recently applied to automate the underwriting process and thus to ease the burden on the underwriters as well as improve underwriting accuracy. However, observational data used for underwriting modelling is high dimensional, sparse and incomplete, due to the dynamic evolving nature (e.g., upgrade) of business information systems. Simply applying traditional supervised learning methods e.g., logistic regression or Gradient boosting on such highly incomplete data usually leads to the unsatisfactory underwriting result, thus requiring practical data imputation for training quality improvement. In this paper, rather than choosing off-the-shelf solutions tackling the complex data missing problem, we propose an innovative Generative Adversarial Nets (GAN) framework that can capture the missing pattern from a causal perspective. Specifically, we design a structural causal model to learn the causal relations underlying the missing pattern of data. Then, we devise a Causality-aware Generative network (CaGen) using the learned causal relationship prior to generating missing values, and correct the imputed values via the adversarial learning. We also show that CaGen significantly improves the underwriting prediction in real-world insurance applications.
Span-Level Emotion Cause Analysis by BERT-based Graph Attention Network
Authors: Xiangju Li, Wei Gao, Shi Feng, Daling Wang, Shafiq R. Joty
Venue: CIKM
Year: 2021

We study the task of span-level emotion cause analysis (SECA), which is focused on identifying the specific emotion cause span(s) triggering a certain emotion in the text. Compared to the popular clause-level emotion cause analysis (CECA), it is a finer-grained emotion cause analysis (ECA) task. In this paper, we design a BERT-based graph attention network for emotion cause span(s) identification. The proposed model takes advantage of the structure of BERT to capture the relationship information between emotion and text, and utilizes graph attention network to model the structure information of the text. Our SECA method can be easily used for extracting clause-level emotion causes for CECA as well. Experimental results show that the proposed method consistently outperforms the state-of-the-art ECA methods on benchmark emotion cause dataset.
Span-level Emotion Cause Analysis with Neural Sequence Tagging
Authors: Xiangju Li, Wei Gao, Shi Feng, Daling Wang, Shafiq R. Joty
Venue: CIKM
Year: 2021

This paper addresses the task of span-level emotion cause analysis (SECA). It is a finer-grained emotion cause analysis (ECA) task, which aims to identify the specific emotion cause span(s) behind certain emotions in text. In this paper, we formalize SECA as a sequence tagging task for which several variants of neural network-based sequence tagging models to extract specific emotion cause span(s) in the given context. These models combine different types of encoding and decoding approaches. Furthermore, to make our models more "emotionally sensitive'', we utilize the multi-head attention mechanism to enhance the representation of context. Experimental evaluations conducted on two benchmark datasets demonstrate the effectiveness of the proposed models.
OTCMR: Bridging Heterogeneity Gap with Optimal Transport for Cross-modal Retrieval
Authors: Mingyang Li, Shao-Lun Huang, Lin Zhang
Venue: CIKM
Year: 2021

Cross-modal retrieval is a classic task in the multimedia community, which aims to search for semantically similar results from different modalities. The core of cross-modal retrieval is to learn the most correlated features in a common feature space for the multi-modal data so that the similarity can be directly measured. In this paper, we propose a novel model using optimal transport for bridging the heterogeneity gap in cross-modal retrieval tasks. Specifically, we calculate the optimal transport plans between feature distributions of different modalities and then minimize the transport cost by optimizing the feature embedding functions. In this way, the feature distributions of multi-modal data can be well aligned in the common feature space. In addition, our model combines the complementary losses in different levels: 1) semantic level, 2) distributional level, and 3) pairwise level for improving cross-modal retrieval performance. In extensive experiments, our method outperforms many other cross-modal retrieval methods, which proves the efficacy of using optimal transport in cross-modal retrieval tasks.
Graph Representation Learning via Adversarial Variational Bayes
Authors: Yunhe Li, Yaochen Hu, Yingxue Zhang
Venue: CIKM
Year: 2021

Methods that learn representations of nodes in a graph play an important role in network analysis. Most of the existing methods of graph representation learning have focused on embedding each node in a graph as a single vector in a low-dimensional continuous space. However, these methods have a crucial limitation: the lack of modeling the uncertainty about the representation. In this work, inspired by Adversarial Variational Bayes (AVB) [22], we propose GraphAVB, a probabilistic generative model to learn node representations that preserve connectivity patterns and capture the uncertainties in the graph. Unlike Graph2Gauss [3] deep which embeds each node as a Gaussian distribution, we represent each node as an implicit distribution parameterized by a neural network in the latent space, which is more flexible and expressive to capture the complex uncertainties in real-world graph-structured datasets. To perform the designed variational inference algorithm with neural samplers, we introduce an auxiliary discriminative network that is used to infer the log probability ratio terms in the objective function and allows us to cast maximizing the objective function as a two-player game. Experimental results on multiple real-world graph datasets demonstrate the effectiveness of our proposed method GraphAVB, outperforming many competitive baselines on the task of link prediction. The superior performances of our proposed method GraphAVB also demonstrate that the downstream tasks can benefit from the captured uncertainty.
Grassland: A Rapid Algebraic Modeling System for Million-variable Optimization
Authors: Xihan Li, Xiongwei Han, Zhishuo Zhou, Mingxuan Yuan, Jia Zeng, Jun Wang
Venue: CIKM
Year: 2021

An algebraic modeling system (AMS) is a type of mathematical software for optimization problems, which allows users to define symbolic mathematical models in a specific language, instantiate them with given source of data, and solve them with the aid of external solver engines. With the bursting scale of business models and increasing need for timeliness, traditional AMSs are not sufficient to meet the following industry needs: 1) million-variable models need to be instantiated from raw data very efficiently; 2) Strictly feasible solution of million-variable models need to be delivered in a rapid manner to make up-to-date decisions against highly dynamic environments. Grassland is a rapid AMS that provides an end-to-end solution to tackle these emerged new challenges. It integrates a parallelized instantiation scheme for large-scale linear constraints, and a sequential decomposition method that accelerates model solving exponentially with an acceptable loss of optimality. Extensive benchmarks on both classical models and real enterprise scenario demonstrate 6-10x speedup of Grassland over state-of-the-art solutions on model instantiation. Our proposed system has been deployed in the large-scale real production planning scenario of Huawei. With the aid of our decomposition method, Grassland successfully accelerated Huawei's million-variable production planning simulation pipeline from hours to 3-5 minutes, supporting near-real-time production plan decision making against highly dynamic supply-demand environment.
Elastic and Stable Compaction for LSM-tree: A FaaS-Based Approach on TerarkDB
Authors: Jianchuan Li, Peiquan Jin, Yuanjin Lin, Ming Zhao, Yi Wang, Kuankuan Guo
Venue: CIKM
Year: 2021

LSM-tree is widely used as a write-optimized storage engine in many NoSQL systems. However, the periodical compaction operations in LSM-tree cost many I/O bandwidths and CPU resources of the local server, resulting in throughput drops of the system. To address this issue, this paper proposes a new compaction scheme based on the FaaS (Functions as a Service) architecture, which is called FaaS Compaction. It utilizes the elastic computing capability of FaaS and always pushes compactions to a FaaS cluster. The FaaS cluster will perform actual compaction operations, which will not affect the processing of the local server. Therefore, we can maintain stable performance even when periodical compactions are triggered. We also present a Parallel Slight Compaction method to solve the timeout problem caused by heavy compactions. We implement the FaaS Compaction based on TerarkDB and a real FaaS cluster and experimentally compare the FaaS Compaction with the RocksDB's local compaction scheme and the state-of-the-art offloading compaction policy. The results suggest the efficiency, stability, and elasticity of our proposal.
Integrating Static and Time-Series Data in Deep Recurrent Models for Oncology Early Warning Systems
Authors: Dingwen Li, Patrick G. Lyons, Jeff Klaus, Brian F. Gage, Marin Kollef, Chenyang Lu
Venue: CIKM
Year: 2021

Machine learning techniques have shown promise in predicting clinical deterioration of hospitalized patients based on electronic health record (EHR). However, building accurate early warning systems (EWS) remains challenging in practice. EHRs are heterogeneous, comprising both static and time-series data. Moreover, missing values are prevalent in both static and time-series data, and the missingness of certain data can be correlated to clinical outcomes. This paper proposes a novel approach for integrating static and time-series clinical data in deep recurrent models through multi-modal fusion. Furthermore, we exploit the correlation of static and time-series data through cross-modal imputation in an integrated recurrent model. We apply the proposed approaches to a dataset extracted from the EHR of 20,700 hospitalizations of adult oncology patients in a research hospital. The experiments demonstrate the proposed approaches outperform the state-of-the-art models in terms of predictive accuracy in generating early warnings for clinical deterioration. A case study further establishes the efficacy of the predictive model for early warning systems under realistic clinical settings.
Detecting the Fake Candidate Instances: Ambiguous Label Learning with Generative Adversarial Networks
Authors: Changchun Li, Ximing Li, Jihong Ouyang, Yiming Wang
Venue: CIKM
Year: 2021

Ambiguous Label Learning (ALL), as an emerging paradigm of weakly supervised learning, aims to induce the prediction model from training datasets with ambiguous supervision, where, specifically, each training instance is annotated with a set of candidate labels but only one is valid. To handle this task, the existing shallow methods mainly disambiguate the candidate labels by leveraging various regularization techniques. Inspired by the great success of deep generative adversarial networks, we apply it to perform effective candidate label disambiguation from a new instance-pivoted perspective. Specifically, for each ALL instance, we recombine its feature representation with each of candidate labels to generate a set of candidate instances, where only one is real and all others are fake. We formulate a unified adversarial objective with respect to three players, i.e., a discriminator, a generator, and a classifier. The discriminator is used to detect the fake candidate instances, so that the classifier can be trained without them. With this insight, we develop a novel ALL method, namely Adversarial Ambiguous Label Learning with Candidate Instance Detection (A2L2CID). Theoretically, we analyze that there is a global equilibrium point between the three players. Empirically, extensive experimental results indicate that A2L2CID outperforms the state-of-the-art ALL methods.