Algorithm-Directed Crash Consistence in Non-Volatile Memory for HPC

Fault tolerance is one of the major design goals for HPC. The emergence of non-volatile memories (NVM) provides a solution to build fault tolerant HPC. Data in NVM-based main memory are not lost when the system crashes because of the non-volatility nature of NVM. However, because of volatile caches, data must be logged and explicitly flushed from caches into NVM to ensure consistence and correctness before crashes, which can cause large runtime overhead. In this paper, we introduce an algorithm-based method to establish crash consistence in NVM for HPC applications. We slightly extend application data structures or sparsely flush cache blocks, which introduce ignorable runtime overhead. Such extension or cache flushing allows us to use algorithm knowledge to \textit{reason} data consistence or correct inconsistent data when the application crashes. We demonstrate the effectiveness of our method for three algorithms, including an iterative solver, dense matrix multiplication, and Monte-Carlo simulation. Based on comprehensive performance evaluation on a variety of test environments, we demonstrate that our approach has very small runtime overhead (at most 8.2\% and less than 3\% in most cases), much smaller than that of traditional checkpoint, while having the same or less recomputation cost.Comment: 12 page

Accuracy Assessment of “Step-by-Step” Simulation Modeling Method for Rock Breaking by TBM Disc Cutters Assisted with Laser

Rock breaking by laser-assisted disc cutters is a novel high-efficiency rock breaking mode that combines mechanical stress induced by the disc cutters with thermal cracking by laser. This paper presented a “step-by-step” simulation modeling concept, and conducted an in-depth study on potential influencing factors of simulation accuracy at each key step. First, the prediction accuracy of laser holes in laser drilling simulation was discussed. Second, the SHPB simulation and experiment were carried out to evaluate the accuracy of the selected material constitutive model in simulating the dynamic fracture damage of rock. Then, taking the laser-assisted rock-penetrating process of the scaled disc cutter as an example, the simulation prediction accuracy of rock-breaking by the disc cutter was analyzed. Finally, the simulation and experiment of laser-assisted disc cutter penetration into rock was carried out, and then the feasibility of the “step-by-step” concept was analyzed. The results show that: (1) in the laser drilling simulation, the predicted accuracy of laser hole size is higher when the power is low; with the laser power increases, the large amount of glass glaze will affect the subsequent modeling accuracy; (2) the HJC model can be used to simulate the transient nonlinear fracture damage behavior of granite; (3) the damage morphology of the granite obtained by the penetration simulation is highly similar to the experimental results, and the load curve should be corrected by the peak point fitting method. The results show the application prospects of the proposed numerical modeling method in future laser-assisted TBM tunnelling

Integration of a prototype wireless communication system with micro-electromechanical temperature and humidity sensor for concrete pavement health monitoring

In recent years, structural health monitoring and management (SHMM) has become a popular approach and is considered essential for achieving well-performing, long-lasting, sustainable transportation infrastructure systems. Key requirements in ideal SHMM of road infrastructure include long-term, continuous, and real-time monitoring of pavement response and performance under various pavement geometry-materials-loading configurations and environmental conditions. With advancements in wireless technologies, integration of wireless communications into sensing device is considered an alternate and superior solution to existing time- and labor-intensive wired sensing systems in meeting the requirements of an ideal SHMM. This study explored the development and integration of a wireless communications sub-system into a commercial off-the-shelf micro-electromechanical sensor-based concrete pavement monitoring system. A success-rate test was performed after the wireless transmission system was buried in the concrete slab, and the test results indicated that the system was able to provide reliable communications at a distance of more than 46 m (150 feet). This will be a useful feature for highway engineers performing routine pavement scans from the pavement shoulder without the need for traffic control or road closure

Establishment of Coal-rock Constitutive Models for Numerical Simulation of Coal-rock Cutting by Conical Picks

One of the key points in numerical simulation of coal-rock cutting by conical picks is to select a proper coal-rock constitutive model. In order to find a reasonable coal-rock constitutive model, a uniaxial compression test was conducted to obtain the constitutive model. The several stages for linear elastic deformation and creep, plastic yielding, hardening, and finally brittle cracking of the constitutive units were studied, and the coal-rock constitutive model was established. As a result, the coal-rock cutting by one conical pick or two conical picks was simulated and the results were compared with coal-rock cutting experiment on a Coal-rock Cutting Machine. According to the simulation and experimental results, it is believed that the numerical simulation can reveal coal-rock crushing process. And the total error rate of coal-rock cutting by one conical pick between the simulation and experiment is 8.5%. The maximum deviation of coal-rock cutting by two conical picks between the simulation and experiment is 9.8%. All simulation values are within a reasonable range. The comparison indicates that the coal-rock constitutive model should better be defined considering the coal-rock crushing process by conical picks

Fractalkine is expressed in the human ovary and increases progesterone biosynthesis in human luteinised granulosa cells

Background: Recent evidence from rodent ovaries has demonstrated expression of fractalkine and the existence of fractalkine receptor, and showed that there is a significant increase in steroidogenesis in response to fractalkine, yet the role of fractalkine and CX3CR1 in the human ovary is still unknown. This study aimed to determine the expression levels of fractalkine and CX3CR1 in the human ovary and to investigate their roles in sexual hormone biosynthesis by human luteinising granulosa cells. This is the first detailed report of fractalkine and CX3CR1 expression and function in the human ovary. Methods: Fractalkine and CX3CR1 expression levels were measured by immunohistochemistry using ovarian tissue from pathological specimens from five individuals. Granulosa cells were obtained from patients during IVF treatment. They were cultured and treated with increasing doses of hCG with or without fractalkine. Media were collected to detect estradiol and progesterone by chemiluminescence. StAR, 3 beta HSD and CYP11A expression were determined in granulosa cells treated with or without fractalkine by real-time RT-PCR. Results: Fractalkine and CX3CR1 were expressed in the human ovary and in luteinising granulosa cells. However, fractalkine expression was stronger in luteinising granulosa cells. Treatment with fractalkine augmented hCG stimulation of progesterone production in a dose-dependent manner with concomitant increases in transcript levels for key steroidogenic enzymes (StAR, 3-beta HSD and CYP11A) but had no effect on estradiol biosynthesis(P < 0.05). Conclusions: Fractalkine and CX3CR1 were found to express in human ovary and luteinising granulosa cells. Fractalkine can increase the biosynthesis of progesterone in a dose-dependent manner by enhancing transcript levels of key steroidogenic enzymes.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000292939500001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Endocrinology & MetabolismReproductive BiologySCI(E)PubMed2ARTICLE95

Analysis and synchronization controller design of dual-port grid-forming voltage-source converters for different operation modes

Grid-tie voltage source converters (VSCs) can operate in three distinct modes: AC-dominant, DC-dominant, and balanced, depending on the placement of the stiff voltage sources. The distinct operation modes of the VSCs traditionally demand different synchronization control techniques, leading to heterogeneous VSCs. It is challenging for the power system to accommodate and coordinate heterogeneous VSCs. A promising universal synchronization control technique for VSCs is the DC-link voltage synchronization control (DVSC) based on a lead compensator (LC). The LC DVSC stabilizes both the DC and AC voltages of a VSC while achieving synchronization with the AC grid. This results in a dual-port grid-forming (DGFM) characteristic for the VSC. However, there has been very limited study on the stability and synchronization controller design of the VSCs with the LC DVSC operating in various modes. To bridge this gap, the paper presents a quantitative analysis on the stability and steady-state performance of the LC DVSC in all three operation modes of the DGFM VSC. Based on the analysis, the paper provides step-by-step design guidelines for the LC DVSC. Furthermore, the paper uncovers an instability issue related to the LC DVSC when the DGFM VSC operates in the balanced mode. To tackle the instability issue, a virtual resistance control is proposed and integrated with the LC DVSC. Simulation results validate the analysis and demonstrate the effectiveness of the DGFM VSC with the LC DVSC designed using the proposed guidelines in all three operation modes. Overall, the paper demonstrates the feasibility of employing the DGFM VSC with the LC DVSC for all three possible operation modes, which can help overcome the challenges associated with accommodating and coordinating heterogeneous VSCs in the power system

TanhReLU -based convolutional neural networks for MDD classification

Major Depression Disorder (MDD), a complex mental health disorder, poses significant challenges in accurate diagnosis. In addressing the issue of gradient vanishing in the classification of MDD using current data-driven electroencephalogram (EEG) data, this study introduces a TanhReLU-based Convolutional Neural Network (CNN). By integrating the TanhReLU activation function, which combines the characteristics of the hyperbolic tangent (Tanh) and rectified linear unit (ReLU) activations, the model aims to improve performance in identifying patterns associated with MDD while alleviating the issue of model overfitting and gradient vanishing. Experimental results demonstrate promising outcomes in the task of MDD classification upon the publicly available EEG data, suggesting potential clinical applications

Research on mobile application support system based on internal and external network

Since 13th Five-Year, great changes have taken place in the situation at home and abroad. Internal and external factors such as “Internet +” innovation and development, new technology driven and information security situation have had a wide and profound impact on the production and operation of enterprises. At the same time, new requirements for information and communication work have been put forward. Based on the existing internal and external network structure of the enterprise, we study a fast response, collaborative innovation, security and controllable mobile application support system, so as to speed up the construction of enterprise mobile applications, and help “Internet +” management innovation and business innovation