Electronic auctions(e-auctions)remove the physical limitations of traditional auctions and bring this mechanism to the general ***,most e-auction schemes involve a trusted auctioneer,which is not always credible in **...
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Electronic auctions(e-auctions)remove the physical limitations of traditional auctions and bring this mechanism to the general ***,most e-auction schemes involve a trusted auctioneer,which is not always credible in *** studies have applied cryptography tools to solve this problem by distributing trust,but they ignore the existence of *** this paper,a blockchain-based Privacy-Preserving and Collusion-Resistant scheme(PPCR)for double auctions is proposed by employing both cryptography and blockchain technology,which is the first decentralized and collusion-resistant double auction scheme that guarantees bidder anonymity and bid privacy.A two-server-based auction framework is designed to support off-chain allocation with privacy preservation and on-chain dispute resolution for collusion resistance.A Dispute Resolution agreement(DR)is provided to the auctioneer to prove that they have conducted the auction correctly and the result is fair and *** addition,a Concise Dispute Resolution protocol(CDR)is designed to handle situations where the number of accused winners is small,significantly reducing the computation cost of dispute *** experimental results confirm that PPCR can indeed achieve efficient collusion resistance and verifiability of auction results with low on-chain and off-chain computational overhead.
With the increasingly complex blockchain technology environment and emerging security threats, the detection and prevention of vulnerabilities in blockchain smart contracts have become crucial for ensuring the healthy...
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Point cloud completion is crucial in point cloud processing, as it can repair and refine incomplete 3D data, ensuring more accurate models. However, current point cloud completion methods commonly face a challenge: th...
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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 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.
Background: Docking mechanism ground simulation test technology has been a significant issue in the aerospace industry. Docking mechanisms must pass various conventional evaluation tests as a class of electromechanica...
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This work investigates how temperature and microstructural evolution affect the formability of face-centered cubic(fcc)structured CoCrFeNiMn0.75Cu0.25 high entropy alloy(HEA)sheets under complex stress *** cupping tes...
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This work investigates how temperature and microstructural evolution affect the formability of face-centered cubic(fcc)structured CoCrFeNiMn0.75Cu0.25 high entropy alloy(HEA)sheets under complex stress *** cupping tests were conducted to quantita-tively evaluate the deformation capacity at room temperature(298 K)and cryogenic *** findings reveal a strong temperature dependence on the formability of the HEA.A decrease in the deformation temperature from 298 to 93 K causes a significant increase in both the Erichsen index(IE)(from 9.8 to 12.4 mm)and the expansion rate(δ)of surface area(from 51.6％to 76.3％),as well as a reduction in the average deviation(η)of thickness(from 55.1％to 44.4％),signifying its ultra-high formability and uniform deformation capability at cryogenic *** enhancement is attributed to the transition in the deformation mechanism from single dislocation slip at 298 K to a cooperative of plastic deformation mechanisms at 93 K,involving dislocation slip,stacking faults(SFs),Lomer-Cottrell(L-C)locks and multi-scale *** lower stacking fault energy of the alloy facilitates these deformation mechanisms,par-ticularly the formation of SFs and nanotwins,which enhance ductility and strength by providing additional pathways for plastic *** mechanisms col-lectively contribute to delaying plastic instability,thereby improving the overall *** work provides a comprehensive understanding of the underlying reasons for the enhanced formability of HEAs at cryogenic tempera-tures,offering valuable insights for their practical use in challenging environments.
The common problem of low strength-ductility matching prevails in near-αhigh-temperature titanium matrix composites(TMCs).In this work,the design strategy of ultrafine grains and dispersed(Ti,Zr)_(6)Si_(3) nanoprecip...
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The common problem of low strength-ductility matching prevails in near-αhigh-temperature titanium matrix composites(TMCs).In this work,the design strategy of ultrafine grains and dispersed(Ti,Zr)_(6)Si_(3) nanoprecipitates in the microstructure of TiB_(w)/nearα-Ti composites via low-temperature isothermal mul-tidirectional forging(IMDF),is expected to break the trade-offdilemma between strength and *** results show that with the decrease in the temperature of IMDF,the grain scale decreased from 0.98 to 0.59μm,and the location of silicide precipitation shifted from phase boundaries and grain boundaries toα-grain boundaries and intracrystalline *** experiments confirm that the local segregation of Si and the temperature of thermomechanical deformation are the key factors affecting the precipitation behavior of *** the decrease of the deformation temperature,the precipitation mechanism of silicides changes from a single diffusion-controlled precipitation to the coupling of two mechanisms,namely,elemental diffusion and dislocation-assisted nucleation,which facilitates the successive precip-itation of nanometer-sized silicides at the grain boundaries and in the inner *** ultimate ten-sile strength(UTS)and elongation of the composites were substantially increased after IMDF at 950 and 800℃,especially the excellent performance at 800℃,where the strength reached 1320.3 MPa and the elongation was 5.8%.The room and high-temperature strengthening and failure mechanisms of the com-posites are analyzed and discussed,and the yield strength(YS)increments provided by various strength-ening mechanisms at room temperature are quantified,aiming to provide a potential preparation strategy for the synergistic strengthening of near-αTMCs with ultrafine grains and nanoparticles.
In the analysis of drone aerial images, object detection tasks are particularly challenging, especially in the presence of complex terrain structures, extreme differences in target sizes, suboptimal shooting angles, a...
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In the analysis of drone aerial images, object detection tasks are particularly challenging, especially in the presence of complex terrain structures, extreme differences in target sizes, suboptimal shooting angles, and varying lighting conditions, all of which exacerbate the difficulty of recognition. In recent years, the DETR model based on the Transformer architecture has eliminated traditional post-processing steps such as NMS(Non-Maximum Suppression), thereby simplifying the object detection process and improving detection accuracy, which has garnered widespread attention in the academic community. However, DETR has limitations such as slow training convergence, difficulty in query optimization, and high computational costs, which hinder its application in practical fields. To address these issues, this paper proposes a new object detection model called OptiDETR. This model first employs a more efficient hybrid encoder to replace the traditional Transformer encoder. The new encoder significantly enhances feature processing capabilities through internal and cross-scale feature interaction and fusion logic. Secondly, an IoU (Intersection over Union) aware query selection mechanism is introduced. This mechanism adds IoU constraints during the training phase to provide higher-quality initial object queries for the decoder, significantly improving the decoding performance. Additionally, the OptiDETR model integrates SW-Block into the DETR decoder, leveraging the advantages of Swin Transformer in global context modeling and feature representation to further enhance the performance and efficiency of object detection. To tackle the problem of small object detection, this study innovatively employs the SAHI algorithm for data augmentation. Through a series of experiments, It achieved a significant performance improvement of more than two percentage points in the mAP (mean Average Precision) metric compared to current mainstream object detection models. Furthermore, ther
Text Summarization is a process to abridge a long-size document into condensed form by comprising all the prime information and central theme. Researchers proposed numerous approaches for automatic text summarization,...
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The equiatomic TiNbZrTaHf alloy was successfully rolled at room temperature with the reduction of ~ 85%. The microstructure and tensile properties were investigated after cold working and annealing. It was determined ...
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The equiatomic TiNbZrTaHf alloy was successfully rolled at room temperature with the reduction of ~ 85%. The microstructure and tensile properties were investigated after cold working and annealing. It was determined that the recrystallization temperature of the TiNbZrTaHf alloy between 850 and 900 ℃. Complete recrystallization and normal grain growth occurred, the high stability of single phase was maintained after annealing at 1000, 1200, and 1400 ℃. But the precipitated phase appeared after long term annealing, as seen after 500 h at 1000 ℃. After cold working, the tensile strength and the elongation of TiNbZrTaHf were 1137 MPa and 25.1%, respectively. The annealed alloy has a high tensile strength (σ_(b )= 863 MPa) and ductility (ε_(e )= 28.5%). Moreover, the oxidation of TiNbZrTaHf alloy at elevated temperatures has a significant impact on its mechanical properties. The poor oxidation resistance of TiNbZrTaHf can accelerate tensile failure by inducing fractures at grain boundaries.
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