The current unsupervised cross‐domain detection methods need source domain data to retrain the detection model in target domain. However, the source domain data may be unavailable due to privacy, decentralization, or computation resource restrictions. A natural idea is to optimize the parameters of the source domain model by self‐supervised learning based on pseudo labels. We propose another approach from the viewpoint of noise perturbation without pseudo‐labeling. It can be assumed that the source and target domains are actually derived from a domain invariant space through domain‐specific perturbations, respectively. A super target domain can be constructed by augmenting more target domain perturbations to the target domain images. The optimal direction of the target domain to the domain invariant space can be approximated as the alignment direction from the super target domain to the target domain. Based on this idea, we propose a novel method called SOAP (SOurce data‐free domain Adaptation through domain Perturbation) which can remove domain perturbation from the target domain. The image‐level, instance‐level, and category consistency regularizations based on Mean Teacher structure are proposed to learn the correct alignment direction. Specifically, the category consistency can also further improve the classification accuracy. Extensive experiments on multiple domain adaptation scenarios demonstrate that SOAP achieves better performance surpassing the baseline (Faster R‐CNN) and multiple state‐of‐the‐art domain adaptation methods which need to access source domain data.

Crowdsensing-based mobile Internet, while facilitating users’ daily life, also raises privacy concerns because of sharing user location trajectories. Combining with open-source network information, these trajectories reveal the semantics of users’ social behaviors in their travels, thus indicating their behavioral traces. Based on such social mobilities, attackers can explore users’ potential behavioral patterns and launch powerful behavioral-semantic inferential attacks for behavior prediction, identity identification, and threatening users’ location-related mobile privacy. Even through privacy protection, the released similar anonymous semantics may still bring significant privacy gains to such attacks. To the best of our knowledge, there is still no effective technique to counter such attacks and protect user behavioral semantics in mobile Internet services. To this end, this article proposes a posterior behavioral-semantic privacy-preserving solution, BSPri, by simulating the inferential attacks to eliminate the privacy risks associated with released traces. Specifically, we represent the logical association between semantic attributes and propose a similar semantic clustering and ranking method. Then, we formalize the user social-mobility stochastic process to characterize the privacy risks arising from the attacker’s observation of the released trajectory, and define a observation-based posterior privacy authentication criteria to filter anonymous semantics further. Finally, we generate synthetic trajectories with similar anonymity semantics, which bring attackers insignificant privacy gain, for users to participate in applications. Extensive experiments with the real-world data set demonstrate that our BSPri achieves an effective privacy-preserving performance, i.e., rigorous posterior-privacy constraint with limited data-availability loss, such as, distance 752 m $(47$ -m closer, compared with our previous work MSP), direction deviation $39.5^{\circ }~(11.5^{\circ }$ smaller), and semantic similarity $43.4\%~(8.4\%$ closer).

Training generative adversarial networks (GANs) for noise-to-image synthesis is a challenge task, primarily due to the instability of GANs’ training process. One of the key issues is the generator’s sensitivity to input data, which can cause sudden fluctuations in the generator’s loss value with certain inputs. This sensitivity suggests an inadequate ability to resist disturbances in the generator, causing the discriminator’s loss value to oscillate and negatively impacting the discriminator. Then, the negative feedback of discriminator is also not conducive to updating generator’s parameters, leading to suboptimal image generation quality. In response to this challenge, we present an innovative GANs model equipped with a learnable auxiliary module that processes auxiliary noise. The core objective of this module is to enhance the stability of both the generator and discriminator throughout the training process. To achieve this target, we incorporate a learnable auxiliary penalty and an augmented discriminator, designed to control the generator and reinforce the discriminator’s stability, respectively. We further apply our method to the Hinge and LSGANs loss functions, illustrating its efficacy in reducing the instability of both the generator and the discriminator. The tests we conducted on LSUN, CelebA, Market-1501, and Creative Senz3D datasets serve as proof of our method’s ability to improve the training stability and overall performance of the baseline methods.

Increasing numbers of artificial intelligence systems are employing collaborative machine learning techniques, such as federated learning, to build a shared powerful deep model among participants, while keeping their training data locally. However, concerns about integrity and privacy in such systems have significantly hindered the use of collaborative learning systems. Therefore, numerous efforts have been presented to preserve the model’s integrity and reduce the privacy leakage of training data throughout the training phase of various collaborative learning systems. This survey seeks to provide a systematic and comprehensive evaluation of security and privacy studies in collaborative training, in contrast to prior surveys that only focus on one single collaborative learning system. Our survey begins with an overview of collaborative learning systems from various perspectives. Then, we systematically summarize the integrity and privacy risks of collaborative learning systems. In particular, we describe state-of-the-art integrity attacks (e.g., Byzantine, backdoor, and adversarial attacks) and privacy attacks (e.g., membership, property, and sample inference attacks), as well as the associated countermeasures. We additionally provide an analysis of open problems to motivate possible future studies.