Unsupervised Domain Adaptation (UDA) aims to leverage knowledge of a well-labeled source domain to learn an effective classifier for an unlabeled target domain. However, a common scenario in real-world applications is that the target domain contains unknown categories that are not observed in the source domain. This setting is termed as open set domain adaptation (OSDA). Most existing approaches of OSDA can only classify known classes well but fail to recognize unknown samples effectively. In this paper, we propose an effective method, named manifold regularized joint transfer (MRJT), for OSDA. MRJT learns new feature representations by simultaneously reducing distribution discrepancy between domains, increasing compactness of within-class, discriminating different known classes, and distinguishing the unknown from the known. The learned new features are projected onto reproducing kernel Hilbert space. In this space, a weighted structural risk minimization method is integrated with manifold regularization to utilize geometric information sufficiently to learn an effective classifier. Extensive experimental results on four real-world datasets verify the superiority of our method. It can not only classify known samples into the right known classes but also recognize unknown samples effectively.

Prevalent domain adaptation approaches are suitable for a close-set scenario where the source domain and the target domain are assumed to share the same data categories. However, this assumption is often violated in real-world conditions where the target domain usually contains samples of categories that are not presented in the source domain. This setting is termed as open set domain adaptation (OSDA). Most existing domain adaptation approaches do not work well in this situation. In this article, we propose an effective method, named joint alignment and category separation (JACS), for OSDA. Specifically, JACS learns a latent shared space, where the marginal and conditional divergence of feature distributions for commonly known classes across domains is alleviated (Joint Alignment), the distribution discrepancy between the known classes and the unknown class is enlarged, and the distance between different known classes is also maximized (Category Separation). These two aspects are unified into an objective to reinforce the optimization of each part simultaneously. The classifier is achieved based on the learned new feature representations by minimizing the structural risk in the reproducing kernel Hilbert space. Extensive experiment results verify that our method outperforms other state-of-the-art approaches on several benchmark datasets.

Multi-agent system investigates the problem of designing a complex system composed of multiple autonomous agents with limited ability and partial observability. As a milestone, AlphaStar has achieved remarkable success in StarCraft II, which is a significant breakthrough in the competitive environments with complex strategic spaces and real-time decisions. However, it poses new challenges for deploying these centralized control models in real-world environments because many of them in such competitive environments were not designed to accommodate the requirements of real-world communication networks, e.g., the problems of high latency and large traffic are inevitable when they are actually deployed. To alleviate this issue, we propose a distributed control paradigm that explicitly splits the control power between the centralized meta-agent and agent units through a combination of centralized and decentralized paradigms. The units can autonomously decide to follow the decisions of the meta-agent or adapt to environment variations immediately by themselves in a decentralized manner. We simulate real-world network environments based on the Mininet platform, experiments based on the StarCraft II Learning Environment (SC2LE) show that our approach achieves a better adaptation in real-world network environments.

Domain adaptation has obtained considerable interest from the literatures of multimedia, especially in cross-domain knowledge transfer problems. In this paper, we propose an effective yet time-saving approach, named Adaptive Component Embedding (ACE), for unsupervised domain adaptation. Specifically, ACE learns adaptive components across domains to embed all data in a shared subspace where the distribution divergence is mitigated and the underlying geometric structures in the local manifold are preserved. Then, an adaptive classifier is learned by using Representer Theorem in the Reproducing Kernel Hilbert Space (RKHS). The objective of our method can be efficiently solved in a closed form. Comprehensive experiments on both standard and large-scale datasets verify that ACE significantly outperforms previous state-of-the-art methods in terms of the classification accuracy and training time.