Generalized Category Discovery (GCD) is a critical task in open-world computing scenarios, aiming to automatically classify partially labeled data by recognizing both known and novel categories. However, existing GCD methods usually suffer from inherent bias toward known categories due to the exclusive pre-training on them and the absence of labeled data of novel categories. This bias can lead to significant misclassification and clustering errors for novel categories. Although recent approaches leverage pseudo-label training and contrastive learning to address this, they still lack explicit supervision to disentangle novel and known categories, resulting in performance bottlenecks. To address these limitations, we propose an Expectation-Maximization-driven Contrastive Disentanglement (EMCD) framework designed to explicitly disentangle novel and known categories. We particularly formulate the identification of novel categories as a latent variable estimation problem. Specifically, it incorporates an EM-disentangling regularization to softly identify novel category samples and a consistency regularization to enhance generalization. In addition, we leverage dual contrastive constraints, including a cluster-sample contrastive constraint and a sample-sample contrastive contrastive, to pull close samples of novel categories while pushing apart ambiguous samples near decision boundaries. Empirical results on 3 commonly used datasets demonstrate that our model is effective and outperforms previous state-of-the-art methods. Our code is available at https://github.com/YWY-only/EMCD.

Homomorphism is an important structure-preserving mapping between graphs. Given a graph G and a pattern Q, the subgraph homomorphism problem is to find a mapping φ from Q to G such that adjacent vertices of Q are mapped to adjacent vertices in G. Unlike the subgraph isomorphic mapping that is injective, homomorphism allows multiple vertices in Q to map to the same vertex in G, increasing complexity. We develop HFrame, the first GNN-based framework for subgraph homomorphism, by combining algorithms and machine learning. We show that HFrame is more expressive than the vanilla GNN, i.e., HFrame can distinguish more graph pairs (Q, G) such that Q is not homomorphic to G. Moreover, we provide a generalization error bound for HFrame. Using real-life and synthetic graphs, we show that HFrame is up to 101.91× faster than exact matching algorithms, and its average accuracy can reach 0.962.

Hierarchical text classification (HTC) aims to assign one or more labels in the hierarchy for each text. Many methods represent this structure as a global hierarchy, leading to redundant graph structures. To address this, incorporating a text-specific local hierarchy is essential. However, existing approaches often model this local hierarchy as a sequence, focusing on explicit parent-child relationships while ignoring implicit correlations among sibling/peer relationships. In this paper, we first integrate local hierarchies into a manual depth-level prompt to capture parent-child relationships. We then apply Mixup to this hierarchical prompt tuning scheme to improve the latent correlation within sibling/peer relationships. Notably, we propose a novel Mixup ratio guided by local hierarchy correlation to effectively capture intrinsic correlations. This Local Hierarchy Mixup (LH-Mix) model demonstrates remarkable performance across three widely-used datasets.

Recent Text-to-SQL methods leverage large language models (LLMs) by incorporating feedback from the database management system. While these methods effectively address execution errors in SQL queries, they struggle with database mismatches--errors that do not trigger execution exceptions. Database mismatches include issues such as condition mismatches and stricter constraint mismatches, both of which are more prevalent in real-world scenarios. To address these challenges, we propose a tool-assisted agent framework for SQL verification and refinement, equipping the LLM-based agent with two specialized tools: a retriever and a detector, designed to diagnose and correct SQL queries with database mismatches. These tools enhance the capability of LLMs to handle real-world questions more effectively. We also introduce SpiderMismatch, a new dataset specifically constructed to reflect the condition mismatch problems encountered in real-world scenarios. Empirical studies demonstrate the effectiveness of our proposed model on Spider and Spider-Realistic datasets in few-shot settings and confirm that our model outperforms baseline methods on SpiderMismatch.

Multi-label text classification (MLTC) assigns multiple labels to a sentence, with the key challenge being capturing label correlations. Existing models prioritize leveraging correlations but often overlook overfitting, while plug-and-play regularization methods fail to preserve correlations effectively. In this paper, we distinguish two types of label correlations: explicit co-occurring correlations and implicit semantic correlations, and propose regularizations on prototypical label embeddings for correlation preservation. Specifically, we first generate the prototypical embedding of multiple co-occurred labels as an intermediate. We then apply a prototypical regularization on the distance between the sentence embedding and corresponding prototypical embedding to alleviate the over-alignment issue caused by binary cross entropy loss and facilitate explicit correlation preservation. We finally extend the vanilla Mixup, which solely mixes multi-hot labels, on prototypical embedding mixing to promote implicit correlation preservation. Empirical studies show the effectiveness of our regularization methods.

Knowledge Graph Completion (KGC) aims to complete KGs by predicting missing entities. A common solution for KGC is Knowledge Graph Embedding (KGE), which assumes that semantical similar entities or relationships should possess similar representations in high-dimensional space. In KGE, a heuristic score function of the head entity and its relation with different operators is required. A typical technique is regularization for tensor factorization, such as the Nuclear-p norm and the Frobenius norm of the query/entity embedding, which significantly improve the KGE model performance on the KGC task. However, the Co-Relation s, including the association between tail entities ( Co-Query Relation ) and the association between queries ( Co-Entity Relation ), desirable for KGC are not fully considered in existing embedding regularization techniques. In this article, we theoretically interpret the role of Co-Relation in KGE and propose a novel ConR regularization approach to learn embedding that takes Co-Relations into account. Extensive experiments show that our model improves static and temporal KGC tasks over decomposition-based models, ComplEx and TuckER. Further analysis of the score cumulative distribution function and embedding visualization demonstrates the effectiveness of ConR .

Temporal Knowledge Graph Forecasting (TKGF) aims to forecast the missing entities or relations at a specific timestamp when only the historical information is observed. It is crucial to accurately identify the historical information of complex temporal relational graphs related to the query. Existing works, e.g., TANGO, have exploited the Neural Ordinary Differential Equation (NODE) to TKGF. However, TANGO encounters two limitations. First, TANGO observes historical facts with only one timestamp at each step, leading to a long-term forgetting problem. Second, TANGO gives the same weight to the entire history graph, including facts that are not relevant to the query. To tackle the above limitations, this paper utilizes Attentional Neural Integral Equation for TKGF (tIE), enabling the global interaction between query-related historical graph sequences. To achieve this, we employ the Relational Graph Convolutional Network and Fourier-type Transformer to model the graph structure and temporal evolution of TKG. The Iterative Integral Equation Solver is exploited to enhance the accuracy and robustness of numerical solutions. The proposed method outperforms baseline models regarding several metrics and inference speed on four benchmark datasets, especially on the long horizontal link forecasting task with irregular time intervals.

Cross-lingual Cross-modal Retrieval (CCR) is an essential task in web search, which aims to break the barriers between modality and language simultaneously and achieves image-text retrieval in the multi-lingual scenario with a single model. In recent years, excellent progress has been made based on cross-lingual cross-modal pre-training; particularly, the methods based on contrastive learning on large-scale data have significantly improved retrieval tasks. However, these methods directly follow the existing pre-training methods in the cross-lingual or cross-modal domain, leading to two problems of inconsistency in CCR: The methods with cross-lingual style suffer from the intra-modal error propagation, resulting in inconsistent recall performance across languages in the whole dataset. The methods with cross-modal style suffer from the inter-modal optimization direction bias, resulting in inconsistent rank across languages within each instance, which cannot be reflected by Recall@K. To solve these problems, we propose a simple but effective 1-to-K contrastive learning method, which treats each language equally and eliminates error propagation and optimization bias. In addition, we propose a new evaluation metric, Mean Rank Variance (MRV), to reflect the rank inconsistency across languages within each instance. Extensive experiments on four CCR datasets show that our method improves both recall rates and MRV with smaller-scale pre-trained data, achieving the new state-of-art.

Text classification is one vital tool assisting web content mining. Semi-supervised text classification (SSTC) offers an approach to alleviate the burden of annotation costs by training on a few labeled texts alongside many unlabeled texts. Unsolved challenges in SSTC are the overfitting problem caused by the limited labeled data and the mislabeling problem of unlabeled texts. To address these issues, this paper proposes a Self-Paced PairWise representation learning (SPPW) model. Concretely, SPPW alleviates the overfitting problem by replacing the overfitting-prone learning of a parameterized classifier with representation learning in a pair-wise manner. Besides, we propose a novel self-paced text filtering method that effectively integrates both label confidence and text hardness to reduce mislabeled texts synergistically. Extensive experiments on 3 benchmark SSTC datasets show that SPPW outperforms baselines and is effective in mitigating overfitting and mislabeling problems.

Text classification is a fundamental task in web content mining. Although the existing supervised contrastive learning (SCL) approach combined with pre-trained language models (PLMs) has achieved leading performance in text classification, it lacks fundamental principles. Theoretically motivated by a derived lower bound of mutual information maximization, we propose a dual contrastive learning framework DualCL that satisfies three properties, i.e., parameter-free, augmentation-easy and label-aware. DualCL generates classifier parameters from the PLM and simultaneously uses them for classification and as augmented views of the input text for supervised contrastive learning. Extensive experiments conclusively demonstrate that DualCL excels in learning superior text representations and consistently outperforms baseline models.

Multimodal relation extraction is a fundamental task of multimodal information extraction. Recent studies have shown promising results by integrating hierarchical visual features from local regions, like image patches, to the broader global regions that form the entire image. However, research to date has largely ignored the understanding of how hierarchical visual semantics are represented and the characteristics that can benefit relation extraction. To bridge this gap, we propose a novel two-stage hierarchical visual context fusion transformer incorporating the mixture of multimodal experts framework to effectively represent and integrate hierarchical visual features into textual semantic representations. In addition, we introduce the concept of hierarchical tracking maps to facilitate the understanding of the intrinsic mechanisms of image information processing involved in multimodal models. We thoroughly investigate the implications of hierarchical visual contexts through four dimensions: performance evaluation, the nature of auxiliary visual information, the patterns observed in the image encoding hierarchy, and the significance of various visual encoding levels. Empirical studies show that our approach achieves new state-of-the-art performance on the MNRE dataset.

Author name disambiguation (AND) is an essential task for online academic retrieval systems. Recent models adopt representation learning in the author's name disambiguation. Despite achieving remarkable success, these methods may be limited in two aspects. First, the heuristically constructed paper association graphs used for representation learning contain uncertainties that may cause negative supervision. Second, existing algorithms, such as binary cross-entropy loss, used to train representation learning models may not produce sufficiently high-quality representations for AND. To tackle the above problems, we propose an association refining and compositional contrasting (ARCC) framework for AND tasks. ARCC first adopts an iterative graph structure refinement process to dynamically reduce the uncertainties in paper graphs. Then, a compositional contrastive learning method is proposed to encourage learning more discriminative representations for AND. Empirical studies on two benchmark datasets suggest that ARCC is effective for AND and outperforms the state-of-the-art models.

Meta-learning has recently promoted few-shot text classification, which identifies target classes based on information transferred from source classes through a series of small tasks or episodes. Existing works constructing their meta-learner on Prototypical Networks need improvement in learning discriminative text representations between similar classes that may lead to conflicts in label prediction. The overfitting problems caused by a few training instances need to be adequately addressed. In addition, efficient episode sampling procedures that could enhance few-shot training should be utilized. To address the problems mentioned above, we first present a contrastive learning framework that simultaneously learns discriminative text representations via supervised contrastive learning while mitigating the overfitting problem via unsupervised contrastive regularization, and then we build an efficient self-paced episode sampling approach on top of it to include more difficult episodes as training progresses. Empirical results on eight few-shot text classification datasets show that our model outperforms the current state-of-the-art models. The extensive experimental analysis demonstrates that our supervised contrastive representation learning and unsupervised contrastive regularization techniques improve the performance of few-shot text classification. The episode-sampling analysis reveals that our self-paced sampling strategy improves training efficiency.

Semi-supervised text classification (STC) has been extensively researched and reduces human annotation. However, existing research assuming that unlabeled data only contains in-distribution texts is unrealistic. This paper extends STC to a more practical Open-set Semi-supervised Text Classification (OSTC) setting, which assumes that the unlabeled data contains out-of-distribution (OOD) texts. The main challenge in OSTC is the false positive inference problem caused by inadvertently including OOD texts during training. To address the problem, we first develop baseline models using outlier detectors for hard OOD-data filtering in a pipeline procedure. Furthermore, we propose a Latent Outlier Softening (LOS) framework that integrates semi-supervised training and outlier detection within probabilistic latent variable modeling. LOS softens the OOD impacts by the Expectation-Maximization (EM) algorithm and weighted entropy maximization. Experiments on 3 created datasets show that LOS significantly outperforms baselines.

Opinion target extraction (OTE) or aspect extraction (AE) is a fundamental task in opinion mining that aims to extract the targets (or aspects) on which opinions have been expressed. Recent work focus on cross-domain OTE, which is typically encountered in real-world scenarios, where the testing and training distributions differ. Most methods use domain adversarial neural networks that aim to reduce the domain gap between the labelled source and unlabelled target domains to improve target domain performance. However, this approach only aligns feature distributions and does not account for class-wise feature alignment, leading to suboptimal results. Semi-supervised learning (SSL) has been explored as a solution, but is limited by the quality of pseudo-labels generated by the model. Inspired by the theoretical foundations in domain adaptation [2], we propose a new SSL approach that opts for selecting target samples whose model output from a domain-specific teacher and student network disagree on the unlabelled target data, in an effort to boost the target domain performance. Extensive experiments on benchmark cross-domain OTE datasets show that this approach is effective and performs consistently well in settings with large domain shifts.

Word Sense Disambiguation (WSD) which aims to identify the correct sense of a target word appearing in a specific context is essential for web text analysis. The use of glosses has been explored as a means for WSD. However, only a few works model the correlation between the target context and gloss. We add to the body of literature by presenting a model that employs a multi-head attention mechanism on deep contextual features of the target word and candidate glosses to refine the target word embedding. Furthermore, to encourage the model to learn the relevant part of target features that align with the correct gloss, we recursively alternate attention on target word features and that of candidate glosses to gradually extract the relevant contextual features of the target word, refining its representation and strengthening the final disambiguation results. Empirical studies on the five most commonly used benchmark datasets show that our proposed model is effective and achieves state-of-the-art results.

Multi-label text classification (MLTC) has a wide range of real-world applications. Neural networks recently promoted the performance of MLTC models. Training these neural-network models relies on sufficient accurately labelled data. However, manually annotating large-scale multi-label text classification datasets is expensive and impractical for many applications. Weak supervision techniques have thus been developed to reduce the cost of annotating text corpus. However, these techniques introduce noisy labels into the training data and may degrade the model performance. This paper aims to deal with such noise-label problems in MLTC in both single-instance and multi-instance settings. We build a novel Neural Expectation-Maximization Framework (nEM) that combines neural networks with probabilistic modelling. The nEM framework produces text representations using neural-network text encoders and is optimized with the Expectation-Maximization algorithm. It naturally considers the noisy labels during learning by iteratively updating the model parameters and estimating the distribution of the ground-truth labels. We evaluate our nEM framework in multi-instance noisy MLTC on a benchmark relation extraction dataset constructed by distant supervision and in single-instance noisy MLTC on synthetic noisy datasets constructed by keywords supervision and label flipping. The experimental results demonstrate that nEM significantly improves upon baseline models in both single-instance and multi-instance noisy MLTC tasks. The experiment analysis suggests that our nEM framework efficiently reduces the noisy labels in MLTC datasets and significantly improves model performance.

Entity alignment is a vital task in knowledge fusion, which aims to align entities from different knowledge graphs and merge them into one single graph. Existing entity alignment models focus on local features and try to minimize the distance between pairs of pre-aligned entities. Despite their success, these models heavily rely on the number of existing pre-aligned entity pairs and the topology information from the rest large set of unaligned entities is still largely unexplored. To overcome the limitation of existing models, we propose a model, termed Global Alignment and Local Information Aggregation, or GALA. GALA constructs global features for the knowledge graphs to be aligned using entity embeddings. It aligns the entities in the graphs by forcing their global features to match with each other and progressively updating the entity embeddings by aggregating local information from the other network. Empirical studies on commonly-used KG alignment data sets confirm the effectiveness of the proposed model.

Information extraction aims at extracting entities, relations, and so on, in text to support information retrieval systems. To extract information, researchers have considered multitask learning (ML) approaches. The conventional ML approach learns shared features across tasks, with the assumption that these features capture sufficient task interactions to learn expressive shared representations for task classification. However, such an assumption is flawed in different perspectives. First, the shared representation may contain noise introduced by another task; tasks coupled for multitask learning may have different complexities but this approach treats all tasks equally; the conventional approach has a flat structure that hinders the learning of explicit interactions. This approach, however, learns implicit interactions across tasks and often has a generalization ability that has benefited the learning of multitasks. In this article, we take advantage of implicit interactions learned by conventional approaches while alleviating the issues mentioned above by developing a Recurrent Interaction Network with an effective Early Prediction Integration (RIN-EPI) for multitask learning. Specifically, RIN-EPI learns implicit and explicit interactions across two different but related tasks. To effectively learn explicit interactions across tasks, we consider the correlations among the outputs of related tasks. It is, however, obvious that task outputs are unobservable during training, so we leverage the predictions at intermediate layers (referred to as early predictions) as proxies as well as shared features across tasks to learn explicit interactions through attention mechanisms and sequence learning models. By recurrently learning explicit interactions, we gradually improve predictions for the individual tasks in the multitask learning. We demonstrate the effectiveness of RIN-EPI on the learning of two mainstream multitasks for information extraction: (1) entity recognition and relation classification and (2) aspect and opinion term co-extraction. Extensive experiments demonstrate the effectiveness of the RIN-EPI architecture, where we achieve state-of-the-art results on several benchmark datasets.

Each link prediction task requires different degrees of answer diversity. While a link prediction task may expect up to a couple of answers, another may expect nearly a hundred answers. Given this fact, the performance of a link prediction model can be estimated more accurately if a flexible number of obtained answers are estimated instead of a predefined number of answers. Inspired by this, in this article, we analyze two evaluation criteria for link prediction tasks, respectively ranking-based protocol and sampling-based protocol. Furthermore, we study two classes of models on link prediction task, direct model and latent-variable model respectively, to demonstrate that latent-variable model performs better under the sampling-based protocol. We then propose a latent-variable model where the framework of Conditional Variational AutoEncoder (CVAE) is applied. Experimental study suggests that the proposed model performs comparably to the current state-of-the-art even under the conventional rank-based protocol. Under the sampling-based protocol, the proposed model is shown to outperform various state-of-the-art models.

Constructing a robust conversation graph based false information detection model is crucial for real social platforms. Recently, graph neural network (GNN) methods for false information detection have achieved significant advances. However, we empirically find that slight perturbations in the conversation graph can cause the predictions of existing models to collapse. To address this problem, we present RDCL, a contrastive learning framework for false information detection on social networks, to obtain robust detection results. RDCL leverages contrastive learning to maximize the consistency between perturbed graphs from the same original graph and minimize the distance between perturbed and original graphs from the same class, forcing the model to improve resistance to data perturbations. Moreover, we prove the importance of hard positive samples for contrastive learning and propose a hard positive sample pairs generation method (HPG) for conversation graphs, which can generate stronger gradient signals to improve the contrastive learning effect and make the model more robust. Experiments on various GNN encoders and datasets show that RDCL outperforms the current state-of-the-art models.

In this paper, we unify a diverse set of learning tasks in NLP, semantic retrieval and related areas, under a common umbrella, which we call unsupervised semantic association learning (USAL). Examples of this generic task include word sense disambiguation, answer selection and question retrieval. We then present a novel modeling framework to tackle such tasks. The framework introduces, under the deep learning paradigm, a latent label indexing the true target in the candidate target set. An EM algorithm is then developed for learning the deep model and inferring the latent variables, principled under variational techniques and noise contrastive estimation. We apply the model and algorithm to several semantic retrieval benchmark tasks and the superior performance of the proposed approach is demonstrated via empirical studies.

Entity linking, which maps named entity mentions in a document into the proper entities in a given knowledge graph, has been shown to be able to significantly benefit from modeling the entity relatedness through Graph Convolutional Networks (GCN). Nevertheless, existing GCN entity linking models fail to take into account the fact that the structured graph for a set of entities not only depends on the contextual information of the given document but also adaptively changes on different aggregation layers of the GCN, resulting in insufficiency in terms of capturing the structural information among entities. In this paper, we propose a dynamic GCN architecture to effectively cope with this challenge. The graph structure in our model is dynamically computed and modified during training. Through aggregating knowledge from dynamically linked nodes, our GCN model can collectively identify the entity mappings between the document and the knowledge graph, and efficiently capture the topical coherence among various entity mentions in the entire document. Empirical studies on benchmark entity linking data sets confirm the superior performance of our proposed strategy and the benefits of the dynamic graph structure.

Supervised learning relies heavily on readily available labelled data to infer an effective classification function. However, proposed methods under the supervised learning paradigm are faced with the scarcity of labelled data within domains, and are not generalized enough to adapt to other tasks. Transfer learning has proved to be a worthy choice to address these issues, by allowing knowledge to be shared across domains and tasks. In this paper, we propose two transfer learning methods Anchored Model Transfer (AMT) and Soft Instance Transfer (SIT), which are both based on multi-task learning, and account for model transfer and instance transfer, and can be combined into a common framework. We demonstrate the effectiveness of AMT and SIT for aspect-level sentiment classification showing the competitive performance against baseline models on benchmark datasets. Interestingly, we show that the integration of both methods AMT+SIT achieves state-of-the-art performance on the same task.

Real-world knowledge bases such as DBPedia, Yago, and Freebase contain sparse linkage connectivity, which poses a severe challenge to link prediction between entities. To cope with such data scarcity issues, recent models have focused on learning interactions between entity pairs by means of relations that exist between them. However promising, some relations are associated with very few tail entities or head entities, resulting in poor estimation of the relation interaction between entities. In this article, we break the sole dependency of modeling relation interactions between entity pairs by associating a triple with pairwise embeddings, i.e., distributed vector representations for pairs of word-based entities and relation of a triple. We capture the interactions that exist between pairwise embeddings by means of a Pairwise Factorization Model that employs a factorization machine with relation attention. This approach allows parameters for related interactions to be estimated efficiently, ensuring that the pairwise embeddings are discriminative, providing strong supervisory signals for the decoding task of link prediction. The Pairwise Factorization Model we propose exploits a neural bag-of-words model as the encoder, which effectively encodes word-based entities into distributed vector representations for the decoder. The proposed model is simple and enjoys efficiency and capability, showing superior link prediction performance over state-of-the-art complex models on benchmark datasets DBPedia50K and FB15K-237.

Knowledge graphs such as DBPedia and Freebase contain sparse linkage connectivity, which poses severe challenge to link prediction between entities. In addressing this sparsity problem, our studies indicate that one needs to leverage model with low complexity to avoid overfitting the weak structural information in the graphs, requiring the simple models which can efficiently encode the entities and their description information and then effectively decode their relationships. In this paper, we present a simple and efficient model that can attain these two goals. Specifically, we use a bag-of-words model, where relevant words are aggregated using average pooling or a basic Graph Convolutional Network to encode entities into distributed embeddings. A factorization machine is then used to score the relationships between those embeddings to generate linkage predictions. Empirical studies on two real datasets confirms the efficiency of our proposed model and shows superior predictive performance over state-of-the-art approaches.

Question answering over knowledge bases aims to take full advantage of the information in knowledge bases with the ultimate purpose of returning answers to questions. To access the substantial knowledge within the KB, many model architectures are hindered by the bottleneck of accurately predicting relations that connect subject entities in questions to object entities in the knowledge base. To break the bottleneck, this article presents a novel model architecture, APVA, which includes a verification mechanism to check the correctness of predicted relations. Specifically, APVA takes advantage of KB-based information to improve relation prediction but verifies the correctness of the predicted relation by means of simple negative sampling in a logistic regression framework. The APVA architecture offers a natural way to integrate an iterative training procedure, which we call turbo training. Accordingly, we introduce APVA-TURBO to perform question answering over knowledge bases. We demonstrate extensive experiments to show that APVA-TURBO outperforms existing approaches on question answering.

Building knowledge base embedding models for link prediction has achieved great success. We however argue that the conventional top-k criterion used for evaluating the model performance is inappropriate. This paper introduces a new criterion, referred to as max-k. Through theoretical analysis and experimental study, we show that the top-k criterion is fundamentally inferior to max-k. We also introduce two prediction protocols for the max-k criterion. These protocols are strongly justified theoretically. Various insights concerning the max-k criterion and the two protocols are obtained through extensive experiments.

The knowledge base (KB) completion problem is usually formulated as a link prediction problem. Such formulation is incapable of capturing certain application scenarios when the KB contains multi-fold relations. In this paper, we present a new formulation of KB completion, called instance reconstruction. Unlike its link-prediction counterpart, which has linear complexity in the size of the KB, this problem has its complexity behave as a high-degree polynomial. This presents a significant challenge in developing scalable instance reconstruction algorithms. In this paper, we present a novel knowledge embedding model (RAE) and build on it an instance reconstruction algorithm (SIR). The SIR algorithm utilizes schema-based filtering as well as "relatedness" filtering for complexity reduction. Here relatedness refers to the likelihood that two entities co-participate in a common instance, and the relatedness metric is learned from the RAE model. We show experimentally that SIR significantly reduces computation complexity without sacrificing reconstruction performance. The complexity reduction corresponds to reducing the KB size by 100 to 1000 folds.

The prediction of trust relationships in social networks plays an important role in the analytics of the networks. Although various link prediction algorithms for general networks may be adapted for this purpose, the recent notion of “trust propagation” has been shown to effectively capture the trust-formation mechanisms and resulted in an effective prediction algorithm. This article builds on the concept of trust propagation and presents a probabilistic trust propagation model. Our model exploits the modern framework of probabilistic graphical models, more specifically, factor graphs. Under this model, the trust prediction problem can be formulated as a statistical inference problem and we derive the belief propagation algorithm as a solver for trust prediction. The model and algorithm are tested using datasets from Epinions and Ciao, by which performance advantages over the previous algorithms are demonstrated.

Electronic Word-of-Mouth (eWOM) is growing exponentially with the rapid development of electronic commerce. As a result, consumers are increasingly crowded by a huge amount of eWOM contents and therefore there is a need to automatically recommend eWOM contents that are helpful to them. Existing helpfulness assessment approaches that deterministically estimate the helpfulness of eWOM contents lack a generative formulation and are limited to the training set that has been voted by many readers. This article presents a rigorous probabilistic framework for inferring the “helpfulness” of eWOM contents which can build a “helpfulness” model from a low number of votes on eWOM contents. Furthermore, we introduce a measurement, “helpfulness” bias, as the benchmark for the “helpfulness” of eWOM documents. We also propose a model that exploits the graphical model and expectation maximization algorithm, under this probabilistic framework, to demonstrate the versatility of our framework. Our algorithm is compared experimentally to other existing helpfulness discovering algorithms and the experimental results show that our framework can effectively model the helpfulness of eWOM contents better than other approaches, and therefore indicate the capability of our framework to recommend helpful eWOMs to potential consumers.

User-generated reviews play an important role for potential consumers in making purchase decisions. However, the quality and helpfulness of user-generated reviews are unavailable unless consumers read through them. Automatically predicting the helpfulness of user-generated reviews can assist consumers in discovering helpful reviews. Existing helpfulness assessing models make use of the positive vote fraction as a benchmark and focus on heuristically finding a ``best guess'' value, which is a point estimate of helpfulness. This benchmark methodology ignores the voter population size and the uncertainty of the helpfulness estimation. In this paper, we propose a user-generated review recommendation model based on the probability density of the review's helpfulness, rather than using the positive vote fraction. Our proposed model exploits probabilistic methodology to infer the helpfulness distribution. Furthermore, our experimental results confirm that our approach can effectively assess the helpfulness of user-generated reviews and recommend the most helpful ones to consumers.

Automatically assessing the quality and helpfulness of consumer reviews is more and more desirable with the evolutionary development of online review systems. Existing helpfulness assessment methodologies make use of the positive vote fraction as a benchmark and heuristically find a "best guess" to estimate the helpfulness of review documents. This benchmarking methodology ignores the voter population size and treats the the same positive vote fraction as the same helpfulness value. We propose a review recommendation approach that make use of the probability density of the review helpfulness as the benchmark and exploit graphical model and Expectation Maximization (EM) algorithm for the inference of review helpfulness. The experimental results demonstrate that the proposed approach is superior to existing approaches.

E-commerce Web sites, such as Amazon.com, provide platforms for consumers to review products and share their opinions. However, it is impossible for consumers to read throughout the huge amount of available reviews. In addition, the quality and helpfulness of reviews are unavailable unless consumers have to read through them.This paper proposes an entropy-based model to predict the helpfulness of reviews. Reviews can be ranked by our entropy-based scoring model and reviews that may help consumers better than others will be found. We also compare our model with several machine learning algorithms. Our experimental results show that our approach is effective in ranking and classifying online reviews. With the predicted helpfulness of reviews, consumers can make purchase decisions more easily.