95 research outputs found
HL-DPoS: An Enhanced Anti-Long-Range Attack DPoS Algorithm
The consensus algorithm is crucial in blockchain for ensuring the validity
and security of transactions across the decentralized network. However,
achieving consensus among nodes and packaging blocks in blockchain networks is
a complex task that requires efficient and secure consensus algorithms. The
DPoS consensus algorithm has emerged as a popular choice due to its fast
transaction processing and high throughput. Despite these advantages, the
algorithm still suffers from weaknesses such as centralization and
vulnerability to long-range attacks, which can compromise the integrity of the
blockchain network.
To combat these problems, we developed an Enhanced Anti-Long-Range Attack
DPoS algorithm (HL-DPoS). First, we split nodes into pieces to reduce
centralization issues while giving witness nodes the power to report and
benefit from malicious node's reports, maintaining high efficiency and high
security. Second, we propose a validation method in HL-DPoS that compares
consensuses transactions with the longest chain to detect long-range attacks.
Algorithm analysis and simulation experiment results demonstrate that our
HL-DPoS consensus algorithm improves security while achieving better consensus
performance
Assessment of Real-Time Compaction Quality Test Indexes for Rockfill Material Based on Roller Vibratory Acceleration Analysis
Compaction quality is directly related to the structure and seepage stability of a rockfill dam. To timely and accurately test the compaction quality of the rockfill material, four real-time test indexes were chosen to characterize the soil compaction degree based on the analysis of roller vibratory acceleration, including acceleration peak value (ap), acceleration root mean square value (arms), crest factor value (CF), and compaction meter value (CMV). To determine which of these indexes is the most appropriate, a two-part field compaction experiment was conducted using a vibratory roller in different filling zones of the dam body. Data on rolling parameters, real-time test indexes, and compaction quality indexes were collected to perform statistical regression analyses. Combined with the spectrum analysis of the acceleration signal, it was found that the CF index best characterizes the compaction degree of the rockfill material among the four indexes. Furthermore, the quantitative relations between the real-time index and compaction quality index were established to determine the control criterion of CF, which can instruct the site work of compaction quality control in the rockfill rolling process
Online AUC maximization
Ministry of Education, Singapore under its Academic Research Funding Tier
Lensless polarimetric coded ptychography (pol-CP) for high-resolution, high-throughput birefringence imaging on a chip
Polarimetric imaging provides valuable insights into the polarization state
of light interacting with a sample. It can infer crucial birefringence
properties of bio-specimens without using any labels, thereby facilitating the
diagnosis of diseases such as cancer and osteoarthritis. In this study, we
introduce a novel polarimetric coded ptychography (pol-CP) approach that
enables high-resolution, high-throughput birefringence imaging on a chip. Our
platform deviates from traditional lens-based polarization systems by employing
an integrated polarimetric coded sensor for lensless diffraction data
acquisition. Utilizing Jones calculus, we quantitatively determine the
birefringence retardance and orientation information of bio-specimens from four
recovered intensity images. Our portable pol-CP prototype can resolve the
435-nm linewidth on the resolution target and the imaging field of view for a
single acquisition is limited only by the detector size of 41 mm^2. The
prototype allows for the acquisition of gigapixel birefringence images with a
180-mm^2 field of view in ~3.5 minutes, achieving an imaging throughput
comparable to that of a conventional whole slide scanner. To demonstrate its
biomedical applications, we perform high-throughput imaging of malaria-infected
blood smears, locating parasites using birefringence contrast. We also generate
birefringence maps of label-free thyroid smears to identify thyroid follicles.
Notably, the recovered birefringence maps emphasize the same regions as
autofluorescence images, indicating the potential for rapid on-site evaluation
of label-free biopsies. The reported approach offers a portable, turnkey
solution for high-resolution, high-throughput polarimetric analysis without
using lenses, with potential applications in disease diagnosis, sample
screening, and label-free chemical imaging
Asp433 in the closing gate of ASIC1 determines stability of the open state without changing properties of the selectivity filter or Ca2+ block
A constriction formed by the crossing of the second transmembrane domains of ASIC1, residues G432 to G436, forms the narrowest segment of the pore in the crystal structure of chicken ASIC1, presumably in the desensitized state, suggesting that it constitutes the “desensitization gate” and the “selectivity filter.” Residues Gly-432 and Asp-433 occlude the pore, preventing the passage of ions from the extracellular side. Here, we examined the role of Asp-433 and Gly-432 in channel kinetics, ion selectivity, conductance, and Ca2+ block in lamprey ASIC1 that is a channel with little intrinsic desensitization in the pH range of maximal activity, pH 7.0. The results show that the duration of open times depends on residue 433, with Asp supporting the longest openings followed by Glu, Gln, or Asn, whereas other residues keep the channel closed. This is consistent with residue Asp-433 forming the pore’s closing gate and the properties of the side chain either stabilizing (hydrophobic amino acids) or destabilizing (Asp) the gate. The data also show residue 432 influencing the duration of openings, but here only Gly and Ala support long openings, whereas all other residues keep channels closed. The negative charge of Asp-433 was not required for block of the open pore by Ca2+ or for determining ion selectivity and unitary conductance. We conclude that the conserved residue Asp-433 forms the closing gate of the pore and thereby determines the duration of individual openings while desensitization, defined as the permanent closure of all or a fraction of channels by the continual presence of H+, modulates the on or off position of the closing gate. The latter effect depends on less conserved regions of the channel, such as TM1 and the extracellular domain. The constriction made by Asp-433 and Gly-432 does not select for ions in the open conformation, implying that the closing gate and selectivity filter are separate structural elements in the ion pathway of ASIC1. The results also predict a significantly different conformation of TM2 in the open state that relieves the constriction made by TM2, allowing the passage of ions unimpeded by the side chain of Asp-433
Seismic Responses of Aqueducts Using a New Type of Self-Centering Seismic Isolation Bearing
An aqueduct is a bridge-like structure that supports a canal passing over a river or low ground, and it is an important part of a water conveyance system. Aqueduct piers are extremely vulnerable to damage during strong earthquakes that can result in structural collapse. Further, excessive seismic displacement will also fracture an aqueduct’s rubber water-stop and interrupt the normal service of an aqueduct after an earthquake. Therefore, improving the seismic capacity and post-earthquake resilience of aqueducts is of great importance. In this paper, a new type of self-centering seismic isolation bearing, the inclined plane guide bearing (IPGB), is proposed for the seismic design of aqueducts, and it is studied both experimentally and numerically. Firstly, a typical aqueduct project and the setting of the IPGBs are introduced. Then, the test design, test cases, and test results of shaking table tests for two different pier-height aqueducts are presented. The seismic responses of the two models are studied, and the results show that the aqueduct that used IPGBs has a smaller bearing displacement and better post-earthquake resilience. Finally, a numerical simulation method applicable to aqueducts using IPGBs is proposed, and its accuracy is verified by comparing the results of the numerical simulation and the shaking table test
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