To satisfy the stringent requirements of emerging broadband services in home networks, a novel Centralized optical and Wi-Fi Access Network (C-WAN) has been proposed within the context of Fiber-to-The-Room (FTTR). In C-WAN, centralized management and control of multiple Wi-Fi access points (APs) deployed in each room are facilitated by relocating portions of Wi-Fi protocols from the APs to a centralized entity. This approach significantly enhances network performance, including throughput and roaming capabilities. However, C-WAN also imposes strict demands on the fronthaul networks, specifically requiring high bandwidth and ultra-low latency. In this context, orthogonal frequency division multiplexing passive optical network (OFDM-PON) emerges as a promising solution to support the C-WAN fronthaul network by allocating dedicated subcarriers to each AP. In C-WAN over OFDM-PON, Wi-Fi stations still contend for access to the wireless channel based on existing Wi-Fi protocols, which may result in prolonged wireless access delays. Consequently, the Quality of Service (QoS) requirements for time-sensitive (TS) services may not be met. Additionally, the variation in maximum Wi-Fi throughput due to the contention-based access mechanism presents a significant challenge for the efficient allocation of optical network resources under stringent delay constraints. To address these issues, we propose a priority-based access mechanism that assigns higher priority to TS services for accessing Wi-Fi channels and obtaining wireless resources. Building on this mechanism, we further develop a Wi-Fi throughput prediction model, which is used to optimize the allocation of optical network resources. Simulation results demonstrate that the proposed scheme can effectively reduce wireless access delay and jitter for TS services, meeting their performance requirements while also improving the utilization of optical network resources.

JSON is a widely used data format for data exchange between application systems and programming frontends. In the Java ecosystem, Java JSON libraries serve as fundamental toolkits for processing JSON data, powering a wide range of real-world applications, such as web services, Android apps, or data management systems. However, without effective quality assurance methods, such as automatic test generation (ATG), developers risk introducing subtle data inconsistency bugs, compatibility issues, and even security vulnerabilities. These flaws can affect billions of end users and potentially cause severe financial losses. Recently, large language models (LLMs) have shown strong potential in enhancing ATG. However, existing LLM-based methods, such as TitanFuzz or YanHui, lack specialization in the JSON domain. For Java JSON libraries, effective bug-triggering test cases should capture the constraints between formatted data and application programs, posing challenges to existing methods, leaving critical aspects of quality assurance unaddressed. To fill this gap, we propose JsonATG, a multi-agent ATG system that generates diverse bug-triggering tests for Java JSON libraries. With historical bug-triggering unit tests as seeds, JSONATG introduces a code summarization agent and a test validation agent into the generation pipeline to produce new, valid test cases. It applies agent-generated program mutation rules tailored specifically for the structural and semantic characteristics of Java JSON libraries, such as data streaming operations, serialization formats, and data-binding patterns. The generated tests are further refined through post-processing to ensure both syntactic and semantic correctness. Our experiments show that JSONATG achieves higher coverage than two state-of-the-art LLM-based test generation methods on the widely used Java JSON library. Using JSONATG with a $\mathbf{\$} 2 5$ budget, we reported 59 bugs (including non-crashing functional bugs) in fastjson, of which 47 were confirmed and 28 have already been fixed.

The rising popularity of large language models (LLMs) has raised concerns about potential abuse and harmful content. As a result, developing a highly generalizable and adaptable machine-generated text (MGT) detection system has become an urgent priority. Given that LLMs are most commonly misused in academic writing, this work investigates the generalization and adaptation capabilities of MGT detectors in three key aspects specific to academic writing: First, we construct MGT-Academic, a large-scale dataset comprising over 336M tokens and 749K samples. MGT-Academic focuses on academic writing, featuring human-written texts (HWTs) and MGTs across STEM, Humanities, and Social Sciences, paired with an extensible code framework for efficient benchmarking. Second, we benchmark the performance of various detectors for binary classification and text attribution tasks in both in-domain and cross-domain settings. This benchmark reveals the often-overlooked challenges of text attribution tasks. Third, we introduce a novel text attribution task in which models must adapt to new classes over time, with little or no access to prior training data, spanning both few-shot and many-shot scenarios. We implement a range of adaptation techniques to enhance performance across these settings. Our findings provide new insights into the generalization ability of MGT detectors and lay the foundation for building robust, adaptive detection systems. The code framework is available at https://github.com/Y-L-LIU/MGTBench-2.0.

Fast approximate nearest neighbor (ANN) search technique for high-dimensional feature indexing and retrieval is the crux of large-scale image retrieval. A recent promising technique is product quantization, which attempts to index high-dimensional image features by decomposing the feature space into a Cartesian product of low-dimensional subspaces and quantizing each of them separately. Despite the promising results reported, their quantization approach follows the typical hard assignment of traditional quantization methods, which may result in large quantization errors, and thus, inferior search performance. Unlike the existing approaches, in this paper, we propose a novel approach called sparse product quantization (SPQ) to encoding the high-dimensional feature vectors into sparse representation. We optimize the sparse representations of the feature vectors by minimizing their quantization errors, making the resulting representation is essentially close to the original data in practice. Experiments show that the proposed SPQ technique is not only able to compress data, but also an effective encoding technique. We obtain state-of-the-art results for ANN search on four public image datasets and the promising results of content-based image retrieval further validate the efficacy of our proposed method.

The conventional bag-of-visual-words (BoW) model is popular for the large-scale object retrieval system but suffers from the critical drawback of ignoring spatial information . RANSAC-based methods attempt to remedy this drawback, but often require traversing all the feature matches for each hypothesis , leading to the heavy computational cost which limits the number of gallery images to be verified for each online query. We propose an efficient direct spatial matching (DSM) approach to directly estimate the scale variation using region sizes, in which all feature matches voted for estimating geometric transformation . DSM is much faster than RANSAC-based methods and exhaustive enumeration approaches. A logarithmic term frequency- inverse document frequency (log tf-idf) weighting scheme is introduced to boost the performance of the base system. We have conducted extensive experimental evaluations on four benchmark datasets for object retrieval. The proposed DSM method, together with a carefully-tailored reranking scheme, achieves the state-of-the-art results on the Oxford buildings and Paris datasets, which demonstrates the efficacy and scalability of our novel DSM technique for large scale object retrieval systems.