Recently, the bottleneck of multi-object tracking is shifting from detection performance to association performance. However, research on association algorithms requires a large number of identity labels, which are more expensive than detection labels. To circumvent the need for identity labels, we propose a Self-supervised Re-identification module for online joint Multi-Object Tracking (SR-MOT). Specifically, we design an appearance discriminator to judge identities based solely on detection hypotheses and then associate the same identity with the final trajectory. To train the discriminator without using identity labels, we construct negative pairs by the detections that appear in the same video frame, as they definitely belong to different identities. Positive pairs are naturally constructed through several useful data augmentation strategies at the box level. In addition, our proposed method balances conflicting detection and re-ID tasks by using different output features and dynamically adjusts detection and re-ID loss weights based on the information content of the loss distribution to promote balance between the two tasks from the feature level and optimization methods. In our evaluation on the MOT Challenge benchmark, we show that our SR-MOT performs comparably to supervised methods and is significantly superior to other unsupervised methods. Our proposed method provides a practical solution for multi-object tracking without the need for identity labels, making it more accessible for real-world applications.

In causal inference, it is common to select a subset of observed covariates, named the adjustment features, to be adjusted for estimating the treatment effect. For real-world applications, the abundant covariates are usually observed, which contain extra variables partially correlating to the treatment (treatment-only variables, e.g., instrumental variables) or the outcome (outcome-only variables, e.g., precision variables) besides the confounders (variables that affect both the treatment and outcome). In principle, unbiased treatment effect estimation is achieved once the adjustment features contain all the confounders. However, the performance of empirical estimations varies a lot with different extra variables. To solve this issue, variable separation/selection for treatment effect estimation has received growing attention when the extra variables contain instrumental variables and precision variables.

Learning individualized causal effect (ICE) plays a vital role in various fields of big data analysis, ranging from fine-grained policy evaluation to personalized treatment development. However, the presence of unmeasured confounders increases the difficulty of estimating ICE in real-world scenarios. A wide range of methods have been proposed to address the unmeasured confounders with the aid of instrument variable (IV), which sources from the treatment randomization. The performance of these methods relies on the well-predefined IVs that satisfy the unconfounded instruments assumption (i.e., the IVs are independent with the unmeasured confounders given observed covariates), which is untestable and leads to finding a valid IV becomes an art rather than science. In this paper, we focus on estimating the ICE with confounded instruments that violate the unconfounded instruments assumption. By considering the conditional independence between the set of confounded instruments and the outcome variable, we propose a novel method, named CVAE-IV, to generate a substitute of the unmeasured confounder with a conditional variational autoencoder. Our theoretical analysis guarantees that the generated confounder substitute will identify unbiased ICE. Extensive experiments on bias demand prediction and Mendelian randomization analysis verify the effectiveness of our method.

This paper studies a long-standing problem of learning the representations of a whole graph without human supervision. The recent self-supervised learning methods train models to be invariant to the transformations (views) of the inputs. However, designing these views requires the experience of human experts. Inspired by adversarial training, we propose an adversarial self-supervised learning (\texttt{GASSL}) framework for learning unsupervised representations of graph data without any handcrafted views. \texttt{GASSL} automatically generates challenging views by adding perturbations to the input and are adversarially trained with respect to the encoder. Our method optimizes the min-max problem and utilizes a gradient accumulation strategy to accelerate the training process. Experimental on ten graph classification datasets show that the proposed approach is superior to state-of-the-art self-supervised learning baselines, which are competitive with supervised models.

Setting up a multidimensional network is an important problem in complex networks and has become a future development trend in the fields of biological gene networks, social networks and so on. A multidimensional network comprises connections and attributes. Community detection in heterogeneous dat asets in different dimensions is more difficult than that in a single network. Traditional methods for dealing with multidimensional networks are ineffective, because of using supervised information or applying strategies for adjusting the graph structure of a single network. In this paper, we propose a semi-supervised community detection method for multidimensional heterogeneous networks. First, we generate a single network by integrating the multidimensional heterogeneous networks. The robust semi-supervised link adjustment strategy is then iteratively applied to the single network to make full use of dynamic supervised information for adding or removing links based on node entropy. Experimental results are obtained by five real multidimensional social datasets. The results show that the proposed method can effectively integrate heterogeneous data. The average accuracy rate and standard mutual information were 90.50% and 93.99%, respectively, representing improvements of 28.97% and 35.06%, respectively, over existing methods.

Machine-learning algorithms are widely applied in traffic classification and anomaly detection. Due to the tremendous traffic on the network, an extremely challenging question arises: how to efficiently and accurately detect the anomalous flow from the backbone network. One solution is proposed, online anomaly-detection scheme, which is based on the sparse feature selection method, Lasso. The sparse feature selection can be efficiently solved by reformulating the problem as an optimization problem with an ℓ1-ball constraint. At the evaluation stage, the authors preprocessed the raw data trace from the trans-Pacific backbone link between Japan and the United States and generated an evaluation data set. Their empirical study shows that the feature selection step can be solved quickly by applying the efficient Euclidean projection method; indeed, doing so resolves the feature selection step faster than using three classical ℓ1-min solvers. In terms of overall accuracy, true positive rate, false positive rate, precision, and F-measure, the proposed scheme improves the quality of detection. Copyright © 2015 John Wiley & Sons, Ltd.