The Person Re-identification (ReID) task aims to match persons across cameras in a surveillance system. In the past few years, many researches are devoted to ReID and its performance has gained significant improvement. ReID models are usually trained as a joint framework comprising a person feature extractor and a classifier. However, there exists co-adaptation between the feature extractor and the classifier, which prevents the feature extractor from making effective and sufficient optimization and results in inferior retrieval performance. In this paper, we propose a very simple and effective training method, called DeAda, to decouple this co-adaptation. Our main motivation is to construct a series of weak classifiers during training by randomization of parameters, so that optimization on the feature extractor could be strengthened in the training stage. DeAda is easy, effective, and efficient, and could serve as a plug-and-play optimization tool for ReID models, without additional memory and time cost. We also analyze the theoretical property of DeAda and show that it could produce identical features for the same person under some simple assumptions. We demonstrate its effectiveness on three public ReID datasets: Market1501, DukeMTMC-reID and CUHK03 over different ReID models. With DeAda optimization, we finally obtain state-of-the-art results on all the three datasets.

Neural Machine Translation (NMT) has become a popular technology in recent years, and the encoder–decoder framework is the mainstream among all the methods. It is obvious that the quality of the semantic representations from encoding is very crucial and can significantly affect the performance of the model. However, existing unidirectional source-to-target architectures may hardly produce a language-independent representation of the text because they rely heavily on the specific relations of the given language pairs. To alleviate this problem, in this paper, we propose a novel Bi-Decoder Augmented Network (BiDAN) for the neural machine translation task. Besides the original decoder which generates the target language sequence, we add an auxiliary decoder to generate back the source language sequence at the training time. Since each decoder transforms the representations of the input text into its corresponding language, jointly training with two target ends can make the shared encoder has the potential to produce a language-independent semantic space. We conduct extensive experiments on several NMT benchmark datasets and the results demonstrate the effectiveness of our proposed approach.

In neural machine translation, lexically constrained decoding generates translation outputs strictly including the constraints predefined by users, and it is beneficial to improve translation quality at the cost of more decoding overheads if the constraints are perfect. Unfortunately, those constraints may contain mistakes in real-world situations and incorrect constraints will undermine lexically constrained decoding. In this article, we propose a novel framework that is capable of improving the translation quality even if the constraints are noisy. The key to our framework is to treat the lexical constraints as external memories. More concretely, it encodes the constraints by a memory encoder and then leverages the memories by a memory integrator. Experiments demonstrate that our framework can not only deliver substantial BLEU gains in handling noisy constraints, but also achieve speedup in decoding. These results motivate us to apply our models to a new scenario where the constraints are generated without the help of users. Experiments show that our models can indeed improve the translation quality with the automatically generated constraints.

Moment retrieval aims to localize the most relevant moment in an untrimmed video according to the given natural language query. Existing works often only focus on one aspect of this emerging task, such as the query representation learning, video context modeling or multi-modal fusion, thus fail to develop a comprehensive system for further performance improvement. In this paper, we introduce a novel Cross-Modal Interaction Network (CMIN) to consider multiple crucial factors for this challenging task, including the syntactic dependencies of natural language queries, long-range semantic dependencies in video context and the sufficient cross-modal interaction. Specifically, we devise a syntactic GCN to leverage the syntactic structure of queries for fine-grained representation learning and propose a multi-head self-attention to capture long-range semantic dependencies from video context. Next, we employ a multi-stage cross-modal interaction to explore the potential relations of video and query contents, and we also consider query reconstruction from the cross-modal representations of target moment as an auxiliary task to strengthen the cross-modal representations. The extensive experiments on ActivityNet Captions and TACoS demonstrate the effectiveness of our proposed method.

The re-identification (ReID) task has received increasing studies in recent years and its performance has gained significant improvement. The progress mainly comes from searching for new network structures to learn person representations. However, limited efforts have been made to explore the potential performance of existing ReID networks directly by better training scheme, which leaves a large space for ReID research. In this paper, we propose a Self-Inspirited Feature Learning (SIF) method to enhance the performance of given ReID networks from the viewpoint of optimization. We design a simple adversarial learning scheme to encourage a network to learn more discriminative person representation. In our method, an auxiliary branch is added into the network only in the training stage, while the structure of the original network stays unchanged during the testing stage. In summary, SIF has three aspects of advantages: 1) it is designed under general setting; 2) it is compatible with many existing feature learning networks on the ReID task; 3) it is easy to implement and has steady performance. We evaluate the performance of SIF on three public ReID datasets: Market1501, DuckMTMC-reID, and CUHK03(both labeled and detected). The results demonstrate significant improvement in performance brought by SIF. We also apply SIF to obtain state-of-the-art results on all the three datasets. Specifically, mAP / Rank-1 accuracy are: 87.6%/95.2% (without re-rank) on Market1501, 79.4%/89.8% on DuckMTMC-reID, 77.0%/79.5% on CUHK03 (labeled) and 73.9%/76.6% on CUHK03 (detected), respectively.