Balanced byzantine reliable broadcast with near-optimal communication and improved computation

CNS-1718135 - National Science Foundation; CNS-1801564 - National Science Foundation; CNS-1931714 - National Science Foundation; CNS-1915763 - National Science Foundation; HR00112020021 - Department of Defense/DARPA; 000000000000000000000000000000000000000000000000000000037211 - SRI Internationalhttps://eprint.iacr.org/2022/776.pdfFirst author draf

Brief announcement: asynchronous verifiable information dispersal with near-optimal communication

CNS-1718135 - National Science Foundation; CNS-1801564 - National Science Foundation; CNS-1931714 - National Science Foundation; CNS-1915763 - National Science Foundation; HR00112020021 - Department of Defense/DARPA; 000000000000000000000000000000000000000000000000000000037211 - SRI Internationalhttps://eprint.iacr.org/2022/775.pdfFirst author draf

Balanced Byzantine Reliable Broadcast with Near-Optimal Communication and Improved Computation

This paper studies Byzantine reliable broadcast (BRB) under asynchronous networks, and improves the state-of-the-art protocols from the following aspects. Near-optimal communication cost: We propose two new BRB protocols for $n$ nodes and input message $M$ that has communication cost $O(n|M|+n^2\log n)$, which is near-optimal due to the lower bound of $\Omega(n|M|+n^2)$. The first RBC protocol assumes threshold signature but is easy to understand, while the second RBC protocol is error-free but less intuitive. Improved computation: We propose a new construction that improves the computation cost of the state-of-the-art BRB by avoiding the expensive online error correction on the input message, while achieving the same communication cost. Balanced communication: We propose a technique named balanced multicast that can balance the communication cost for BRB protocols where the broadcaster needs to multicast the message $M$ while other nodes only needs to multicast coded fragments of size $O(|M|/n + \log n)$. The balanced multicast technique can be applied to many existing BRB protocols as well as all our new constructions in this paper, and can make every node incur about the same communication cost. Finally, we present a lower bound to show the near optimality of our protocol in terms of communication cost at each node

Asynchronous Verifiable Information Dispersal with Near-Optimal Communication

We present a near-optimal asynchronous verifiable information dispersal (AVID) protocol. The total dispersal cost of our AVID protocol is $O(|M|+\kappa n^2)$, and the retrieval cost per client is $O(|M|+\kappa n)$. Unlike prior works, our AVID protocol only assumes the existence of collision-resistant hash functions. Also, in our AVID protocol, the dispersing client incurs a communication cost of $O(|M|+\kappa n)$ in comparison to $O(|M|+\kappa n\log n)$ of prior best. Moreover, each node in our AVID protocol incurs a storage cost of $O(|M|/n+\kappa)$ bits, in comparison to $O(|M|/n+\kappa \log n)$ bits of prior best. Finally, we present lower bound results on communication cost and show that our AVID protocol has near-optimal communication costs -- only a factor of $O(\kappa)$ gap from the lower bounds

In situ atomic scale mechanisms of strain-induced twin boundary shear to high angle grain boundary in nanocrystalline Pt

Twin boundary can both strengthen and soften nanocrystalline metals and has been an important path for improving the strength and ductility of nano materials. Here, using in-lab developed double-tilt tensile stage in the transmission electron microscope, the atomic scale twin boundary shearing process was in situ observed in a twin-structured nanocrystalline Pt. It was revealed that the twin boundary shear was resulted from partial dislocation emissions on the intersected {111} planes, which accommodate as large as 47% shear strain. It is uncovered that the partial dislocations nucleated and glided on the two intersecting {111} slip planes lead to a transition of the original symmetric tilt ∑3/(111) coherent twin boundary into a symmetric tilt ∑9/(114) high angle grain boundary. These results provide insight of twin boundary strengthening mechanisms for accommodating plasticity strains in nanocrystalline metals

Investigation on sensorless operation of two new fault-tolerant interior permanent magnet motors with trade-off of fault tolerance and flux-intensifying effects

In this paper, two new fault-tolerant interior permanent magnet (FT-IPM) motors are proposed and compared for achieving high fault tolerance and sensorless operating capacity under multiple operations. Most previous studies regarding FT-IPM motors aim to improve fault-tolerant capability but suffer from the saliency characteristic problem, which is unfavorable for sensorless control. To overcome this issue, the design idea of flux-intensifying effect is innovatively proposed. Based on this, two new FT-IPM motors with different rotor structures and slot-pole combinations are developed to achieve flux-intensifying effect. To explore the impact of different motor structures and slot-pole combinations on motor performances, the simulation and experimental results of the two motors are compared and discussed in detail. The comparison results indicate that good fault tolerance and sensorless operating performances need tradeoffs, which provide a reference for balancing the fault tolerance and sensorless operating capacity

Study on the factors of hydrogen sulfide production from lignite bacterial sulfate reduction based on response surface method

Abstract Bacterial sulfate reduction (BSR) is one of the key factors leading to the anomalous accumulation of hydrogen sulphide in coal mines. Environmental factors such as temperature and pH play a crucial role in the metabolism and degradation of coal by sulfate-reducing bacteria (SRB). In this study, coal samples were selected from Shengli Coal Mine, and SRB strains were isolated and purified from mine water using a dilution spread-plate anaerobic cultivation method. Based on single-factor experiments and response surface methodology (RSM), the impact of temperature, pH, oxidation–reduction potential (ORP), chemical oxygen demand to sulfate ratio (COD/SO4 2−) on the generation of hydrogen sulphide during brown coal BSR was analyzed. The results showed that the anaerobic degradation of coal by SRB was inhibited by either too high or too low a temperature to produce hydrogen sulfide, and the greatest production of hydrogen sulfide occurred at a temperature of about 30 °C; The greatest production of hydrogen sulfide occurred at an initial ambient pH of 7.5; COD/SO4 2− ratio of around 2.0 is most conducive to hydrogen sulphide generation; the lower ORP value is more favorable for hydrogen sulfide generation. The optimal conditions obtained by RSM were: temperature of 30.37 °C, pH of 7.64 and COD/SO4 2− of 1.96. Under these conditions, the hydrogen sulfide concentration was 56.79 mg/L, the pH value was 8.40, the ORP value was −274 mV, and the SO4 2− utilization rate was 58.04%. The RSM results showed that temperature, ambient pH and COD/SO4 2− had a significant effect on hydrogen sulfide production, and the degree of effect was: ambient pH > temperature > COD/SO4 2−

Electrochemical tip-enhanced Raman spectroscopy for in situ characterization of materials and reactions

Surfaces and interfaces play a key role in heterogeneous electrochemical reactions, as the reactants need to interact with the surface. Therefore, it is extremely important to develop a method to probe the surface structure and the interaction of the reactant or product with the surface to achieve a better understanding to rationally design the electrochemical systems. In this regard, tip-enhanced Raman spectroscopy (TERS) appears to be an ideal tool for studying the complex electrochemical interfaces. TERS is an organic integration of scanning probe microscopy, Raman spectroscopy, and localized surface plasmon resonance. It can not only obtain the topological but also vibrational information of a sample at the nanometer resolution.Published versio

Electroacupuncture Alleviates Pain-Related Emotion by Upregulating the Expression of NPS and Its Receptor NPSR in the Anterior Cingulate Cortex and Hypothalamus

Objective. Electroacupuncture (EA) is reported effective in alleviating pain-related emotion; however, the underlying mechanism of its effects still needs to be elucidated. The NPS-NPSR system has been validated for the involvement in the modulation of analgesia and emotional behavior. Here, we aimed to investigate the role of the NPS-NPSR system in the anterior cingulate cortex (ACC), hypothalamus, and central amygdala (CeA) in the use of EA to relieve affective pain modeled by complete Freund’s adjuvant- (CFA-) evoked conditioned place aversion (C-CPA). Materials and Methods. CFA injection combined with a CPA paradigm was introduced to establish the C-CPA model, and the elevated O-maze (EOM) was used to test the behavioral changes after model establishment. We further explored the expression of NPS and NPSR at the protein and gene levels in the brain regions of interest by immunofluorescence staining and quantitative real-time PCR. Results. We observed that EA stimulation delivered to the bilateral Zusanli (ST36) and Kunlun (BL60) acupoints remarkably inhibited sensory pain, pain-evoked place aversion, and anxiety-like behavior. The current study showed that EA significantly enhanced the protein expression of this peptide system in the ACC and hypothalamus, while the elevated expression of NPSR protein alone was just confined to the affected side in the CeA. Moreover, EA remarkably upregulated the mRNA expression of NPS in CeA, ACC, and hypothalamus and NPSR mRNA in the hypothalamus and CeA. Conclusions. These data suggest the effectiveness of EA in alleviating affective pain, and these benefits may at least partially be attributable to the upregulation of the NPS-NPSR system in the ACC and hypothalamus

Application of artificial intelligence-assisted compressed sensing combined with three types of fat-suppressed T₂WI techniques

Objective To explore the advantages of artificial intelligence-assisted compressed sensing （ACS） combined with three types of fat-suppressed T2WI techniques in image quality， scanning time and scheme selection. Methods In 30 patients with low back pain who underwent conventional lumbar magnetic resonance imaging （MRI） plain scan， ACS combined with 5 groups of sagittal （SAG） fat-suppressed T2WI sequences were added to original examination sequence. Frequency-selective fat saturation （FS）， water-fat separation （WFI） and short tau inversion recovery （STIR） techniques were employed. ACS-SAG-T2WI-FS （group A， n=30）， Acs-SAG-T2WI-WFI （group B， n=30）， ACS-SAG-STIR （group C n=30）， SAG-T2WI-FS （group D， n=30）， SAG-T2WI-WFI （group E， n=30） and SAG-STIR sequences （group F， n=30） were employed. Objective evaluation indicators of signal-to-noise ratio （SNR） and contrast-to-noise ratio （CNR） and subjective evaluation by two radiologists were carried out to assess the effect. Results The SNR and CNR of the fourth vertebra， the fourth and fifth intervertebral discs and the same spinal cord in group A were higher than those in group D. The SNR and CNR of the fourth vertebra， the fourth and fifth intervertebral discs， and the same spinal cord in group B were higher than those in group E. The SNR and CNR of the fourth vertebra， the fourth and fifth intervertebral discs， and the same spinal cord in group C were higher compared with those in group F （all P < 0.01）. The imaging time in group A was shortened by 13.2% compared with that in group D. The imaging time in group B was reduced by 8.9% compared with that in group E. The imaging time in group C was reduced by 12.4% compared with that in group F （all P < 0.01）. The subjective scores by two radiologists for groups A， B and C were significantly higher than those in groups D， E and F （all P < 0.01；The scores of the two physicians were consistent， Kappa=0.972， P <0.01）. Conclusions The combination of ACS and three types of fat-suppressed T2WI techniques （FS， WFI and STIR） is superior to use of fat-suppressed T2WI techniques alone. ACS-SAG-T2WI-FS sequence is recommended with the shortest imaging time and the highest image quality. ACS-SAG-T2WI-WFI sequence provides multiple groups of phase images， and the time advantage difference is the second choice. ACS-SAG-STIR sequence has the most stable fat-suppression capability， which can be used as the last option