The existing nearest neighbor query methods cannot directly perform the nearest neighbor query of specified geographical direction *** order to compensate the shortcomings of the existing methods,a directional nearest...
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The existing nearest neighbor query methods cannot directly perform the nearest neighbor query of specified geographical direction *** order to compensate the shortcomings of the existing methods,a directional nearest neighbor query method in specific direction space based on Voronoi diagram is put *** work studies two cases,*** query point is static and the query point moves with a constant *** the static condition,the corresponding pruning method and the pruning algorithm of the specified direction nearest neighbor(pruning_SDNN algorithm)are proposed by combining the plane right-angle coordinate system with the north-west direction,and then according to the smallest external rectangle of Voronoi polygon,the specific query is made and the direction nearest neighbor query based on Voronoi rectangle(VR-DNN) algorithm is *** the case of moving with a constant velocity,first of all,the combination of plane right angle coordinate system,geographical direction and circle are used,the query range is determined and pruning methods and the pruning algorithm of the direction nearest neighbor based on decision circle(pruning_DDNN algorithm) are put ***,according to the different position of motion trajectory and Voronoi diagram,a specific query through the nature of Voronoi diagram is *** last,the direction nearest neighbor query based on Voronoi diagram and motion trajectory(VM-DNN) algorithm is put *** theoretical research and experiments show that the proposed algorithm can effectively deal with the problem of the nearest neighbor query for a specified geographical direction space.
Video deblurring is a fundamental problem in low-level vision, and many methods have employed designs based on CNNs and transformers. Traditional CNNs often require deeper architectures to achieve a larger receptive f...
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Model simulation plays an important role in modern engineering design and system development. It simulates and validates complex systems through a virtual environment, reduces the cost and risk of physical tests, and ...
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Accurate identification of malicious traffic is crucial for implementing effective defense countermeasures and has led to extensive research efforts. However, the continuously evolving techniques employed by adversari...
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Accurate identification of malicious traffic is crucial for implementing effective defense countermeasures and has led to extensive research efforts. However, the continuously evolving techniques employed by adversaries have introduced the issues of concept drift, which significantly affects the performance of existing methods. To tackle this challenge, some researchers have focused on improving the separability of malicious traffic representation and designing drift detectors to reduce the number of false ***, these methods often overlook the importance of enhancing the generalization and intraclass consistency in the representation. Additionally, the detectors are not sufficiently sensitive to the variations among different malicious traffic classes, which results in poor performance and limited robustness. In this paper, we propose intraclass consistency enhanced variational autoencoder with Class-Perception detector(ICE-CP) to identify malicious traffic under concept drift. It comprises two key modules during training:intraclass consistency enhanced(ICE) representation learning and Class-Perception(CP) detector construction. In the first module, we employ a variational autoencoder(VAE) in conjunction with Kullback-Leibler(KL)-divergence and cross-entropy loss to model the distribution of each input malicious traffic flow. This approach simultaneously enhances the generalization, interclass consistency, and intraclass differences in the learned representation. Consequently, we obtain a compact representation and a trained classifier for nondrifting malicious traffic. In the second module, we design the CP detector, which generates a centroid and threshold for each malicious traffic class separately based on the learned representation, depicting the boundaries between drifting and non-drifting malicious traffic. During testing, we utilize the trained classifier to predict malicious traffic classes for the testing samples. Then, we use the CP det
In numerical weather prediction(NWP),the parameterization of orographic drag plays an important role in representing subgrid orographic *** subgrid orographic parameters are the key input to the parameterization of or...
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In numerical weather prediction(NWP),the parameterization of orographic drag plays an important role in representing subgrid orographic *** subgrid orographic parameters are the key input to the parameterization of orographic ***,the subgrid orographic parameters in most NWP models were produced based on elevation datasets generated many years ago,with a coarse resolution and low *** this paper,using the latest high-quality elevation data and considering the applicable scale range of the subgrid orographic parameters,we construct the orographic parameters,including the subgrid orographic standard deviation,anisotropy,orientation,and slope,that are required as input to the orographic gravity wave drag(OGWD)***,we introduce the newly constructed orographic parameters into the Yin-He Global Spectral Model(YHGSM),optimize the description of the orographic effect in the model,and improve the simulation of two typical heavy rainfall events in Beijing and Henan.
The Grey Wolf optimizer (GWO) is an efficient meta-heuristic algorithm based on swarm intelligence, inspired by the hierarchical structure and hunting behavior of natural wolf packs. Due to straightforward algorithm f...
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This paper presents an electromagnetic three-dimensional vibration energy harvesting device that uses an oblique cross-spring vibrator structure to collect low-frequency vibration *** oblique cross-spring structure al...
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This paper presents an electromagnetic three-dimensional vibration energy harvesting device that uses an oblique cross-spring vibrator structure to collect low-frequency vibration *** oblique cross-spring structure allowed the center vibrator to vibrate in any *** with six-directional coils,this configuration senses and harvests environmental vibrations across all directions and ***,the dynamics of the oblique cross-spring vibrator structure were analyzed and a finite element simulation was performed for the magnet arrangement and mode shape of the structure.A prototype is designed,fabricated,and experimentally *** results showed that the efficiency of the three-dimensional energy output was higher under the same excitation,which was 2.7 times higher than that of the unidirectional *** unidirectional output power with load is 0.94 mW at 11 Hz under 0.3 g base *** highest total output power of the prototype was 50 mW when it was fixed to the leg at a running speed of 8 km/***,the energy harvesting scheme proposed in this study has a considerable low-frequency output effect,which provides a novel means of improving the electrical performance of energy harvesting systems for self-powered IoT and sensor devices.
With the development of ultra-wide coverage technology,multibeam echo-sounder(MBES)system has put forward higher requirements for localization accuracy and computational efficiency of ray tracing *** classical equival...
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With the development of ultra-wide coverage technology,multibeam echo-sounder(MBES)system has put forward higher requirements for localization accuracy and computational efficiency of ray tracing *** classical equivalent sound speed profile(ESSP)method replaces the measured sound velocity profile(SVP)with a simple constant gradient SVP,reducing the computational workload of beam ***,in deep-sea environment,the depth measurement error of this method rapidly increases from the central beam to the edge *** analyzing the positioning error of the ESSP method at edge beam,it is discovered that the positioning error increases monotonically with the incident angle,and the relationship between them could be expressed by polynomial ***,an error correction algorithm based on polynomial fitting is *** simulation experiment conducted on an inclined seafloor shows that the proposed algorithm exhibits comparable efficiency to the original ESSP method,while significantly improving bathymetry accuracy by nearly eight times in the edge beam.
With economic and social development, the impact of climate change on human social life is constantly deepening. The ability to accurately predict trends in meteorological data has become an important area of research...
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This study applies single-valued neutrosophic sets, which extend the frameworks of fuzzy and intuitionistic fuzzy sets, to graph theory. We introduce a new category of graphs called Single-Valued Heptapartitioned Neut...
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