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Fuzzers have proven to be a vital tool in identifying vulnerabilities. As an area of active research, there is a constant drive to improve fuzzers, and it is equally important to improve benchmarks used to evaluate their performance alongside evolving heuristics. Current research has primarily focused on using CVE bugs as benchmarks, with synthetic benchmarks receiving less attention due to concerns about overfitting specific fuzzing heuristics. In this paper, we introduce ShadowBug, a new methodology that generates enhanced synthetic bugs. In contrast to existing synthetic benchmarks, our approach involves well-arranged bugs that fit specific distributions by quantifying the constraint-solving difficulty of each block. We also uncover implicit constraints of real-world bugs that prior research has overlooked and develop an integer-overflow-based transformation from normal constraints to their implicit forms. We construct a synthetic benchmark and evaluate it against five prominent fuzzers. The experiments reveal that 391 out of 466 bugs were detected, which confirms the practicality and effectiveness of our methodology. Additionally, we introduce a finer-grained evaluation metric called “bug difficulty,” which sheds more light on their heuristic strengths with regard to constraint-solving and bug exploitation. The results of our study have practical implications for future fuzzer evaluation methods.

One of the main goals in biogeography and ecology is the study of patterns of species diversity and the driving factors in these patterns. However, such studies have not focused on Sternorrhyncha in China, although this region hosts massive species distribution data. Here, based on the 15,450 distribution records of Sternorrhyncha species in China, we analyzed patterns in species richness and endemism at 1° × 1° grid size and determined the effects of environmental variables on these patterns using correlations analysis and the model averaging approach. We found that species richness and endemism of Sternorrhyncha species are unevenly distributed, with high values in the eastern and southeastern coastal regions of mainland China, as well as Taiwan Island. Furthermore, the key factors driving species richness and endemism patterns are inconsistent. Species richness patterns were strongly affected by the normalized difference vegetation index, which is closely related to the feeding habits of Sternorrhyncha, whereas endemism patterns were strongly affected by the elevation range. Therefore, our results indicate that the range size of species should be considered to understand the determinants of species diversity patterns.

Fuzzing, an automated software testing technique, has achieved remarkable success in recent years, aiding developers in identifying vulnerabilities. However, fuzzing can also be exploited by attackers to discover zero-day vulnerabilities. To counter this threat, researchers have proposed anti-fuzzing techniques, which aim to impede the fuzzing process by slowing the program down, providing misleading coverage feedback, and complicating data flow, etc. Unfortunately, current anti-fuzzing approaches primarily focus on enhancing defensive capabilities while underestimating the associated overhead and manual efforts required. In our paper, we present No-Fuzz, an efficient and practical anti-fuzzing technique. No-Fuzz stands out in binary-only fuzzing by accurately determining running environments, effectively reducing unnecessary fake block overhead, and replacing resource-intensive functions with lightweight arithmetic operations in anti-hybrid techniques. We have implemented a prototype of No-Fuzz and conducted evaluations to compare its performance against existing approaches. Our evaluations demonstrate that No-Fuzz introduces minimal performance overhead, accounting for less than 10% of the storage cost for a single fake block. Moreover, it achieves a significant 92.2% reduction in total storage costs compared to prior works for an equivalent number of branch reductions. By emphasizing practicality, our study sheds light on improving anti-fuzzing techniques for real-world deployment.

The rapid extinction of species is of considerable concern for biodiversity conservation. Identifying the drivers of species diversity and hotspots is beneficial for developing conservation strategies. Studies on insects have mainly focused on terrestrial species and rarely on semiaquatic species. Using 135,208 georeferenced occurrence records of 296 damselflies across North America, their species richness and endemism (represented by weighted endemism) patterns were mapped in a 100 × 100-km grid size, and the effects of environmental variables on species richness and endemism were investigated using generalized linear models and hierarchical partitioning. Subsequently, the top 5% grids with species richness and weighted endemism were separately selected as hotspots and their congruence was evaluated. Finally, species diversity hotspots were identified by integrating two types of hotspot grids, and gap analysis was performed to evaluate their conservation status. Temperature conditions and water availability had the strongest influence on species richness and endemism, respectively. Low congruence among species richness and endemism hotspots was observed. Moreover, four species diversity hotspots were identified, namely, region of the eastern United States and southeastern Canada, southwestern United States, central Mexico, and southernmost North America. Approximately 69.31% of the hotspot grids are not a part of the existing protected areas, presenting a significant conservation gap. The habitats of taxonomic groups should be considered while identifying the most common driving mechanisms of endemism. Strengthening the establishment of protected areas in regions with conservation gaps is urgently needed to promote the conservation of damselflies in North America.

This study aimed to identify the main factors driving species richness and endemism patterns of Chinese wild Rhododendron as well as to assess the hotspots of species diversity and their conservation status. We initially mapped the species richness and endemism (expressed by weighted endemism) patterns of 546 wild Rhododendron in China in 100 × 100 km grids using 13,969 occurrence records. Subsequently, the effects of environmental variables on species richness and endemism patterns were assessed using regression models, and hotspots were identified based on the areas overlapping in 10% of the grids with the highest species richness and endemism. Finally, the conservation status of the hotspots was evaluated via gap analysis. The key environmental variables affecting species richness and endemism patterns differed. Species richness patterns were significantly influenced by moisture index, whereas endemism patterns were significantly influenced by elevation range. Moreover, the following five species diversity hotspots were identified: southern Xizang, Hengduan Mountains, south-central Sichuan, eastern Yungui Plateau, and central Gansu; however, these hotspots are not fully covered by the existing nature reserves. Our results indicate that the establishment of nature reserves should be actively promoted to effectively protect wild Rhododendron in hotspots with a conservation gap.

Aiming at the development requirements of large load capacity and long life of wheel-side deceleration system， a logarithmic modified composite roller movable tooth transmission is proposed. Combined with the current research on the contact deformation of hollow roller， a method for calculating the meshing deformation of logarithmic modified composite roller is proposed by introducing design parameters Δc and Δe. The influence of filling degree and different rollers on meshing stiffness is analyzed. The finite element method is used to compare and analyze the equivalent stress distribution of different rollers. The results show that under the same load conditions， the meshing stiffness of the logarithmic modified composite roller movable tooth is slightly higher than that of the hollow roller， and the meshing stiffness decreases with the increase of the filling degree. The logarithmic modified composite roller can effectively improve the edge stress concentration and reduce the maximum equivalent stress.

Studies on endemism are always of high interest in biogeography and contribute to better understanding of the evolution of species and making conservation plans. The present study aimed to investigate the endemism patterns of planthoppers in China by delimiting centers of endemism and areas of endemism. We collected 6,907 spatial distribution records for 860 endemic planthopper species from various resources. Centers of endemism were identified using weighted endemism values at 1° grid size. Parsimony analysis of endemicity and endemicity analysis were employed to detect areas of endemism at 1°, 1.5°, and 2° grid sizes. Six centers of endemism located in mountainous areas were identified: Taiwan Island, Hainan Island, eastern Yungui Plateau, Wuyi Mountains, western Qinling Mountains, and western Yunnan. We also delimited six areas of endemism, which were generally consistent with centers of endemism. Our findings demonstrated that mountainous areas have an essential role in facilitating the high level of endemism and formation of areas of endemism in planthoppers through the combined effects of complex topography, a long-term stable environment, and geological events. Dispersal ability and distribution of host plants also have important effects on the patterns of planthoppers’ endemism.