In modern systems, memory copy remains a critical performance bottleneck across various scenarios, playing a pervasive role in system-wide execution such as syscalls, IPC, and user-mode applications. Numerous efforts have aimed at optimizing copy performance, including zero-copy with page remapping and hardware-accelerated copy. However, they typically target specific use cases, such as Linux zero-copy send() for messages of ≥10KB. This paper argues for copy as a first-class OS service, offering three key benefits: (1) with the asynchronous copy abstraction provided by the service, applications can overlap their execution with copy; (2) the service can effectively utilize hardware capabilities to enhance copy performance; (3) the service's global view of copies further enables holistic optimization. To this end, we introduce Copier, a new OS service of coordinated asynchronous copy, to serve both user-mode applications and OS services. We build Copier-Linux to demonstrate Copier's ability to improve performance for diverse use cases, including Redis, Protobuf, network stack, proxy, etc. Evaluations show that Copier achieves up to a 1.8 × speedup for real-world applications like Redis and a 1.6 × improvement over zIO, the state-of-the-art in optimizing copy efficiency. To further facilitate adoption, we develop a toolchain to ease the use of Copier. We also integrate Copier into a commercial smartphone OS (HarmonyOS 5.0), achieving promising results.

How to represent the object more appropriately in oriented object detection is an essential problem to be solved, there are many solutions for the object represented. It is a relatively novel approach to represent objects as a number of sample points useful for both localization and recognition. However, the current point-set-based representation methods do not effectively supervise all points for learning, and the internal information of the convex hull in the point set cannot be effectively learned. Therefore, this letter proposes point set distance (PSD) loss, which learns set-to-set supervision of objects to effectively represent objects. Besides, most of the current sample selection strategies are based on the Intersection over Union (IoU), but these methods cannot comprehensively measure candidate samples quality. To select high-quality point sets, we propose to use the probability distribution of point sets to select the positive samples. Our probabilistic point set sample selection (PPSS) scheme effectively exploits the classification information, regression information, and the distribution characteristics of the point set. Experimental results on remote sensing image datasets including DOTA, DIOR-R, and HRSC2016, demonstrate the proposed method for arbitrary-oriented object detection achieves consistent and substantial improvements.

Arbitrary-oriented objects exist widely in remote sensing images. The mainstream rotation detectors use oriented bounding boxes (OBBs) or quadrilateral bounding boxes (QBBs) to represent the rotating objects. However, these methods suffer from the representation ambiguity for oriented object definition, which leads to suboptimal regression optimization and the inconsistency between the loss metric and the localization accuracy of the predictions. In this letter, we propose a representation invariance loss (RIL) to optimize the bounding box regression for the rotating objects in the remote sensing images. RIL treats multiple representations of an oriented object as multiple equivalent local minima and hence transforms bounding box regression into an adaptive matching process with these local minima. Next, the Hungarian matching algorithm is adopted to obtain the optimal regression strategy. Besides, we propose a normalized rotation loss to alleviate the weak correlation between different variables and their unbalanced loss contribution in OBB representation. Extensive experiments on remote sensing datasets show that our method achieves consistent and substantial improvement. The code and models are available athttps://github.com/ming71/RIDetto facilitate future research.

Object detection in optical remote-sensing images is an important and challenging task. In recent years, the methods based on convolutional neural networks (CNNs) have made good progress. However, due to the large variation in object scale, aspect ratio, as well as the arbitrary orientation, the detection performance is difficult to be further improved. In this article, we discuss the role of discriminative features in object detection, and then propose a critical feature capturing network (CFC-Net) to improve detection accuracy from three aspects: building powerful feature representation, refining preset anchors, and optimizing label assignment. Specifically, we first decouple the classification and regression features, and then construct robust critical features adapted to the respective tasks of classification and regression through the polarization attention module (PAM). With the extracted discriminative regression features, the rotation anchor refinement module (R-ARM) performs localization refinement on preset horizontal anchors to obtain superior rotation anchors. Next, the dynamic anchor learning (DAL) strategy is given to adaptively select high-quality anchors based on their ability to capture critical features. The proposed framework creates more powerful semantic representations for objects in remote-sensing images and achieves high-performance real-time object detection. Experimental results on three remote-sensing datasets including HRSC2016, DOTA, and UCAS-AOD show that our method achieves superior detection performance compared with many state-of-the-art approaches. Code and models are available athttps://github.com/ming71/CFC-Net.