In this paper, we investigate the problem of sum rate maximization by guaranteeing the quality of service (QoS) of both uplink and downlink in cell-free with network-assisted full Duplexing (NAFD), where the users operate in half-duplex mode and access points (APs) operate in either full-duplex mode or half-duplex mode. In the considered network, the central processor unit (CPU) sends the compressed beamformed signals to the transmit-APs (T-APs) over the downlink fronthaul, and the T-APs forward the signals to downlink users. At the same time, the receive-APs (R-APs) compress the signals transmitted by uplink users and forward them to the CPU via uplink fronthaul. We aim to maximize the spectral efficiency and the number of users that should be admitted by the network, where users’ requirements of both downlink and uplink signal-to-interference-plus-noise (SINR) constraints, fronthaul capacity constraints, energy harvesting constraints and simultaneous wireless information and power transfer (SWIPT) ratio design are considered. A successive convex approximation-based algorithm is proposed to solve the highly coupled problem, which is guaranteed to converge to the Karush-Kuhn-Tucker (KKT) conditions. We conduct a comprehensive comparison between the NAFD scheme and the traditional co-frequency co-time full duplex (CCFD) scheme and time division duplex (TDD) scheme and offer some valuable opinions about the system design.

Underwater organisms are an important part of the underwater ecological environment. More and more attention has been paid to the perception of underwater ecological environment by intelligent means, such as machine vision. However, many objective reasons affect the accuracy of underwater biological detection, such as the low-quality image, different sizes or shapes, and overlapping or occlusion of underwater organisms. Therefore, this paper proposes an underwater biological detection algorithm based on improved Faster-RCNN. Firstly, the ResNet is used as the backbone feature extraction network of Faster-RCNN. Then, BiFPN (Bidirectional Feature Pyramid Network) is used to build a ResNet–BiFPN structure which can improve the capability of feature extraction and multi-scale feature fusion. Additionally, EIoU (Effective IoU) is used to replace IoU to reduce the proportion of redundant bounding boxes in the training data. Moreover, K-means++ clustering is used to generate more suitable anchor boxes to improve detection accuracy. Finally, the experimental results show that the detection accuracy of underwater biological detection algorithm based on improved Faster-RCNN on URPC2018 dataset is improved to 88.94%, which is 8.26% higher than Faster-RCNN. The results fully prove the effectiveness of the proposed algorithm.

Arbitrarily-oriented object detection is a challenging task. Since the object orientation in remote sensing images is arbitrary, using horizontal bounding boxes will lead to low detection accuracy. Existing regression-based rotation detectors can lead to the problem of boundary discontinuity. In this paper, we propose a remote sensing image object detection method based on angle classification that uses rotation detection bounding boxes with angle information to detect objects. Specifically, we incorporate the neural architecture search framework with feature pyramid network (NAS-FPN) module in a dense detector (RetinaNet) and use a binary encoding method in angle classification. This method reduces the background influence, so that there is almost no overlap between detection boxes. Based on the angles of the detection boxes, we can infer the information of the motion direction of the target and further determine the motion trajectory of the target. We conducted ablation experiments on a large publicly available for object detection in an aerial imagery (DOTA) to verify the effectiveness of each module in the method and compared the method with several other detection methods. The experimental results demonstrate the effectiveness of our method.

Enhancing low-light images presents several challenges, such as image darkness, severe color distortion, and noise. To address these issues, we propose a novel low-light image enhancement algorithm with nested skip connections based on UNet++. This design facilitates the propagation of finer features and improves information transmission, resulting in better enhancement of image brightness, reduction of color distortion, and retention of finer details. To eliminate noise potentially introduced by skip connections, we designed a specific residual block based on Instance Normalization (IN). IN can process each sample independently, allowing the model to better adapt to each image's specific lighting conditions and noise levels. In addition, we propose a new hybrid loss function that simultaneously emphasizes multiple critical attributes of an image, yielding superior enhancement results on multiple key metrics. The proposed algorithm achieves advanced performance on the LOL dataset, scoring 23.0047 and 0.8682 on the PSNR and SSIM metrics, respectively. Extensive experiments demonstrate the effectiveness and superiority of our proposed algorithm. The code is available at https://github.com/xiwang-online/LLUnetPlusPlus.