Medical image generation plays an important role in clinical applications, particularly in modality translation tasks such as CT-to-MRI synthesis. Compared with supervised methods that rely on paired datasets, unsupervised image generation is more practical due to its lower data requirements. However, existing unsupervised methods often suffer from insufficient high-frequency detail preservation and poor style consistency. Although wavelet transform offers promising multi-scale representation capabilities, effectively integrating it into deep generative models remains challenging. To address these issues, we propose WDS-Net (Wavelet-based Dual-branch Style-consistent Network). In the content encoder, wavelet decomposition is used to separate the image into low-frequency structural and high-frequency detail components, which are processed through a dual-branch architecture and then fused to enhance content representation. A multi-scale feature extraction mechanism is employed in the style encoder, and layer-wise style injection is applied during decoding to improve style consistency. Experimental results demonstrate that WDS-Net can generate high-quality MRI images under unpaired training conditions and achieves robust performance even with limited data. Evaluations on both public and clinical datasets confirm that WDS-Net outperforms existing methods in detail preservation and style consistency, showing strong potential for real-world clinical applications.

This paper addresses the optimal output regulation problem for discrete-time linear systems with completely unknown dynamics and unmeasurable exosystem states. The primary objective is to design incremental dataset-based value iteration (VI) reinforcement learning algorithms to derive both state feedback and output feedback controllers. In the context of data-driven optimal control , existing approaches typically require either the exosystem state to be measurable or the design of an autonomous system to reconstruct it. In contrast, this work proposes an incremental dataset-based VI algorithm, which eliminates the need for exosystem state measurement or reconstruction. Additionally, the proposed method allows for the selection of an arbitrary initial admissible control policy, thereby overcoming the challenge of requiring an initial admissible control in policy iteration algorithms. Furthermore, the system state is reconstructed using the incremental dataset, and an optimal output feedback controller is developed based on the proposed VI algorithm. The theoretical convergence of the dataset-based incremental VI algorithm is rigorously analyzed, and comprehensive simulations are conducted to validate its effectiveness.

In recent years, significant achievements have been made in the field of histopathological image analysis using convolutional neural networks (CNNs). However, existing CNNs fail to fully capture the important local structures and regional information in histopathological images due to the complex tissue structures and variable pathological features present in these images. They often treat all regions equally, which further exacerbates the challenge of accurately analyzing such images. Current network model can’t extract deep layer features efficiently without guiding. To alleviate this problem, we propose a novel network model called Multi-Position Supervised Soft Attention (MPSA). MPSA adds regions of interest (RoI) labels at multiple feature layers for deep supervision, and then uses the supervised layers as soft attention to guide the learning of the classification network, enabling the network to accurately extract features of the lesion target. Additionally, we design a Multi-level Attention Feature Enhancement Module (MAFEM), which combines multiple levels of attention mechanisms to enhance the performance of the convolutional neural network in histopathological image classification . MAFEM includes spatial attention , soft attention of the main branch, and our proposed soft attention for multi-branch feature fusion . The proposed soft attention for multi-branch feature fusion aims to enhance the predictive performance of the classification model by activating relevant neurons in the diagnostic area in a highly activated state, while effectively avoiding noise activation. This innovative approach ensures that the model can focus on the most pertinent information, leading to improved classification accuracy . We conducted classification experiments on the liver cancer histopathological images dataset and the results showed that our method achieved a classification accuracy of 95.79%, indicating that it is very effective in the analysis of liver histopathological images. Our proposed network architecture has also demonstrated good generalization ability in other medical datasets, achieving a classification accuracy of 84.41% on the ultrasound carotid plaque dataset.

This technical article conducts the research on the cooperative output regulation problem (CORP) of linear heterogeneous discrete-time multiagent systems (MASs) with the constraints of unknown dynamics. On the basis of the data-driven scheme, a state-based distributed control protocol is constructed to achieve the asymptotic tracking for leader system’s reference signals while getting rid of external disturbances. Furthermore, the result is extended to the output-based case based on the least square approach. In order to cope with the unknown leader system, an observer is put forward to estimate the leader’s state after obtaining the system matrices for the exosystem by utilizing the persistently exciting data. To further overcome the difficulties of the unknown dynamics of each follower, input-output relationship is constructed to infer the system matrices. Moreover, the solution to the unknown regulator equations is provided by solving the data-dependent matrix equations. Ultimately, the control gains are derived by solving the convex optimization problem. The affirmation of the whole design scheme is demonstrated by two simulation cases.

The work in this paper delves into the challenge of whole elongated body's obstacle avoidance during path following for a class of bionic snake robots. Currently, most studies focus solely on preventing the robot's head from colliding with obstacles through designed controllers. However, due to the unique elongated structure and biomimetic locomotion modes of snake robots, it is unavoidable that the rest of the robot's body could still collide with obstacles. To resolve this problem, we propose a novel real-time optimization obstacle avoidance strategy for a class of terrestrial snake robots with multi-link elongated body using model predictive control (MPC). Moreover, by leveraging the elongated body characteristics of the robot, an improved path guidance strategy is also developed. The effectiveness of the proposed strategies is verified and validated through extensive simulations and experiments on a custom-built nine-link elongated snake robot. The results demonstrate that all links of the robot can well avoid obstacles while continuing to track the given path.

High-dimensional multi-label data is widespread in practical applications, which brings great challenges to the research field of pattern recognition and machine learning. Many feature selection algorithms have been proposed in recent years, among which the filtering feature selection algorithm is the most popular one because of its simplicity. Therefore, filtering feature selection has become a hot research topic, especially the multi-label feature selection algorithm based on mutual information. In the algorithm, the computation cost of high dimensional mutual information is expensive. How to approximate high order mutual information based on low order mutual information has become a major research direction. To our best knowledge, all existing feature selection algorithms that consider the label correlation will increase the computational cost greatly. Therefore, this paper proposes an approximation method of three-dimensional interaction information, which is applied to the calculation of correlation and redundancy. It can take the correlation of labels into account and don’t increase the computation cost significantly at the same time. Experiments analysis results show that the proposed method is effective.

In this paper, the distributed control problem of nonlinear strict-feedback multiagent systems is addressed under directed and time-invariant communication graphs. With the utilization of the prescribed performance control methodology, a control algorithm is proposed to ensure predefined bounds of overshoot, convergence rates, and steady-state values of the neighborhood synchronization errors in the presence of unknown dead-zone inputs. The algorithm is fully distributed in the sense that the control input for each agent is independent of any global information of the communication graph and is solely based on local relative output information from its neighborhood set. The approximating structures, e.g., neural networks or fuzzy systems, and the command filters that are typically incorporated to avoid the need for analytical derivatives in the backstepping design are not employed here, resulting in a low-complexity design. Simulation results are included to verify the algorithm.

In this paper, a simple tracking control scheme is proposed for quadrotor systems with uncertain dynamics. It precludes the necessity for prohibitive analytic computation of the derivatives of the desired (virtual) attitude that is typically employed in controlling quadrotor systems. Moreover, this control scheme is approximation-free in the sense that it does not incorporate any adaptive laws, observers, or command filters to compensate for unknown parameters in the dynamics and the absence of the analytic differentiation, thus exhibiting remarkably low complexity levels and making its implementation straightforward. The thrust saturation is approached in the position control design which also enables the singularity in desired attitude extraction to be avoided entirely. It is demonstrated that based on the proposed scheme, the tracking errors can be made arbitrarily small by appropriately selecting design parameters. Extensive simulations and experiments are performed to verify the effectiveness of our scheme.

This paper investigated the visual servoing regulation of nonholonomic mobile robots with monocular camera. Nonholonomic kinematic systems with visual feedback are uncertain and more involved in comparison with common kinematic systems. Two-phase technique was used to present a robust controller that enabled the mobile robot image pose and the orientation regulation despite the lack of depth information and the lack of precise visual parameters. The most interesting feature of this paper is that the problem was discussed in the image frame and the inertial frame, which made the problem easy and useful. The stabilization of the system by using the proposed method was rigorously proved. The simulation was given to show the effectiveness of the presented controllers.

This paper addresses visual servoing of a robot manipulator with uncalibrated intrinsic and extrinsic parameters of the vision system and unknown physical parameters of the manipulator. A novel sliding mode visual feedback scheme is proposed to solve the problem of the robust trajectory tracking of a planar manipulator in the image frame without calibrating the camera parameters. The controller does not use visual velocity so as to achieve high and robust performance with low sampling rate of the vision system. It is proved by Lyapunov direct method that the tracking error of the robot converges to an arbitrarily small neighborhood of zero. The simulation is included to demonstrate the effectiveness of the controller proposed.

This paper is concerned with the stabilization problem of multiple chained form control systems with input constraints. A new controller presented can stabilize the system to an arbitrarily, small /spl epsi/-neighborhood of its equilibrium in a finite time. This is achieved by the sliding mode approach and a multi-step control strategy. The application of it to a nonholonomic wheeled mobile robot is described. Simulation result shouts that the proposed controller is effective.