A Heterogeneous Virtual Machines Resource Allocation Scheme in Slices Architecture of 5G Edge Datacenter

In the paper, we investigate the heterogeneous resource allocation scheme for virtual machines with slicing technology in the 5G/B5G edge computing environment. In general, the different slices for different task scenarios exist in the same edge layer synchronously. A lot of researches reveal that the virtual machines of different slices indicate strong heterogeneity with different reserved resource granularity. In the condition, the allocation process is a NP hard problem and difficult for the actual demand of the tasks in the strongly heterogeneous environment. Based on the slicing and container concept, we propose the resource allocation scheme named Two-Dimension allocation and correlation placement Scheme (TDACP). The scheme divides the resource allocation and management work into three stages in this paper: In the first stage, it designs reasonably strategy to allocate resources to different task slices according to demand. In the second stage, it establishes an equivalent relationship between the virtual machine reserved resource capacity and the Service-Level Agreement (SLA) of the virtual machine in different slices. In the third stage, it designs a placement optimization strategy to schedule the equivalent virtual machines in the physical servers. Thus, it is able to establish a virtual machine placement strategy with high resource utilization efficiency and low time cost. The simulation results indicate that the proposed scheme is able to suppress the problem of uneven resource allocation which is caused by the pure preemptive scheduling strategy. It adjusts the number of equivalent virtual machines based on the SLA range of system parameter, and reduces the SLA probability of physical servers effectively based on resource utilization time sampling series linear. The scheme is able to guarantee resource allocation and management work orderly and efficiently in the edge datacenter slices

Spatial and temporal change in the potential evapotranspiration sensitivity to meteorological factors in China (1960–2007)

National Natural Science Foundation of China 40971023;National Basic Research Program of China 2010CB428406 Potential evapotranspiration (E(0)), as an estimate of the evaporative demand of the atmosphere, has been widely studied in the fields of irrigation management, crop water demand and predictions in ungauged basins (PUBs). Analysis of the sensitivity of E(0) to meteorological factors is a basic research on the impact of climate change on water resources, and also is important to the optimal allocation of agricultural water resources. This paper dealt with sensitivity of E(0) over China, which was divided into ten drainage systems, including Songhua River basin, Liaohe River basin, Haihe River basin, Yellow River basin, Yangtze River basin, Pearl River basin, Huaihe River drainage system, Southeast river drainage system, Northwest river drainage system and Southwest river drainage system. In addition, the calculation method of global radiation in Penman-Monteith formula was improved by optimization, and the sensitivities of Penman-Monteith potential evapotranspiration to the daily maximum temperature (S(Tmax)), daily minimum temperature (S(Tmin)), wind speed (S(U2)), global radiation (S(Rs)) and vapor pressure (S(VP)) were calculated and analyzed based on the long-term meteorological data from 653 meteorological stations in China during the period 1960-2007. Results show that: (1) the correlation coefficient between E(0) and pan evaporation increased from 0.61 to 0.75. E(0) had the decline trends in eight of ten drainage systems in China, which indicates that "pan evaporation paradox" commonly exists in China from 1960 to 2007. (2) Spatially, T(max) was the most sensitive factor in Haihe River basin, Yellow River basin, Huaihe River drainage system, Yangtze River basin, Pearl River basin and Southeast river drainage system, and VP was the most sensitive factor in Songhua River Basin, Liaohe River basin, Northwest river drainage system while R(s) was the most sensitive factor in Southwest river drainage system. For the nation-wide average, the most sensitive factor was VP, followed by T(max), R(s), U(2) and T(min). In addition, the changes in sensitivity coefficients had a certain correlation with elevation. (3) Temporally, the maximum values of S(Tmax) and S(Rs) occurred in July, while the maximum values of S(Tmin), S(VP) and S(U2) occurred in January. Moreover, trend analysis indicates that S(Tmax) had decline trends, while S(Tmin), S(U2), S(Rs) and S(VP) had increasing trends

Numerical methods to simulate spontaneous imbibition in microscopic pore structures: A review

Spontaneous imbibition, as a fundamental flow phenomenon, is widely utilized in fossil energy production, carbon dioxide and underground hydrogen storage. With the development of computing, the exploration of flow laws of spontaneous imbibition has evolved from macroscopic theoretical models to pore-scale numerical analysis. Currently, the solutions for multiphase flow in pore media mainly consider the volume of fluid and the phase field, and have been classed into level set methods based on macroscopic Navier-Stokes equations and the Shan-Chen, free energy, color gradient, and phase-field methods based on mesoscopic lattice Boltzmann equations. However, no comprehensive review article has summarized the strengths and limitations of these methods. Therefore, this work focuses on critically reviewing and commenting on the fundamentals and limitations of porescale models applied to spontaneous imbibition. In addition, recent works applying these methods are systematically reviewed. Our study aims to provide the scientific community with an expert opinion to understand the basic methods for solving the existing problems of spontaneous imbibition in porous media. Future research directions are suggested, namely, focusing on developing the reconstruction pore medium algorithms, establishing modeling methods for non-stationary states, exploring the flow laws in mixed wetting conditions, linking macroscopic and microscopic flow laws, and developing models for coupled multiphase flow numerical computation with machine learning. Overall, this review provides a comprehensive understanding of spontaneous imbibition simulation methods, promotes a thorough knowledge of spontaneous imbibition in porous media, provides guidance on exploring flow laws, and inspires researchers to give more credit to spontaneous imbibition studies.Document Type: Invited reviewCited as: Zhou, Y., Guan, W., Zhao, C., Zou, X., He, Z., Zhao, H. Numerical methods to simulate spontaneous imbibition in microscopic pore structures: A review. Capillarity, 2024, 11(1): 1-21. https://doi.org/10.46690/capi.2024.04.0

Spontaneous imbibition behavior in porous media with various hydraulic fracture propagations: A pore-scale perspective

Hydraulic fracturing technology can improve the geologic structure of unconventional oil and gas reservoirs, yielding a complex fracture network resulting from the synergistic action of hydraulic and natural fractures. However, the impact of spontaneous imbibition associated with hydraulic fracture propagation on the reservoir matrix remains poorly understood. In this study, combining the Cahn-Hilliard phase field method with the Navier-Stokes equations, pore-scale modeling was employed to capture the evolution of the oil-water interface during dynamic spontaneous imbibition for hydraulic fracture propagation in a two-end open mode. This pore-scale modeling approach can effectively circumvent the challenges of conducting spontaneous imbibition experiments on specimens partitioned by hydraulic fractures. A direct correlation was established between the pressure difference curve and the morphology of discharged oil phase in the primary hydraulic fracture, providing valuable insights into the distribution of oil phase in spontaneous imbibition. Furthermore, it was shown that secondary hydraulic fracture propagation expands the longitudinal swept area and enhances the utilization of natural fractures in the transverse swept area during spontaneous imbibition. When secondary hydraulic fracture propagation results in the interconnection of upper and lower primary hydraulic fractures, competitive imbibition occurs in the matrix, leading to reduced oil recovery compared to the unconnected models. Our results shed light upon the spontaneous imbibition mechanism in porous media with hydraulic fracture propagation, contributing to the refinement and application of hydraulic fracturing techniques.Document Type: Original articleCited as: Zhou, Y., Guan, W., Zhao, C., Zou, X., He, Z., Zhao, H. Spontaneous imbibition behavior in porous media with various hydraulic fracture propagations: A pore-scale perspective. Advances in Geo-Energy Research, 2023, 9(3): 185-197. https://doi.org/10.46690/ager.2023.09.0

Highly toughened polylactide with novel sliding graft copolymer by in situ reactive compatibilization, crosslinking and chain extension

YesThe “sliding graft copolymer” (SGC), in which many linear poly-ε-caprolactone (PCL) side chains are bound to cyclodextrin rings of a polyrotaxane (PR), was prepared and employed to toughen brittle polylactide (PLA) with methylene diphenyl diisocyanate (MDI) by reactive blending. The SGC was in situ crosslinked and therefore transformed from a crystallized plastic into a totally amorphous elastomer during reactive blending. Meanwhile, PLA-co-SGC copolymer was formed at interface to greatly improve the compatibility between PLA and SGC, and the chain extension of PLA also occurred, were confirmed by FTIR, GPC, SEM, and TEM. The resulting PLA/SGC/MDI blends displayed super impact toughness, elongation at break and nice biocompatibility. It was inferred from these results the crosslinked SGC (c-SGC) elastomeric particles with sliding crosslinking points performed as stress concentrators and absorbed considerable energy under impact and tension process.This work was supported by the National Natural Science Foundation of China (50933001, 51221002 and 51320105012)

Parallelization and I/O performance optimization of a global nonhydrostatic dynamical core using MPI

The Global ‐ Regional Integrated forecast SysTem (GRIST) is the next- generation weather and climate integrated model dynamic framework developed by Chinese Academy of Meteorological Sciences. In this paper, we present several changes made to the global nonhydrostatic dynamical (GND) core, which is part of the ongoing prototype of GRIST. The changes leveraging MPI and PnetCDF techniques were targeted at the parallelization and performance optimization to the original serial GND core. Meanwhile, some sophisticated data structures and interfaces were designed to adjust flexibly the size of boundary and halo domains according to the variable accuracy in parallel context. In addition, the I/O performance of PnetCDF decreases as the number of MPI processes increases in our experimental environment. Especially when the number exceeds 6000, it caused system-wide outages (SWO). Thus, a grouping solution was proposed to overcome that issue. Several experiments were carried out on the supercomputing platform based on Intel x86 CPUs in the National Supercomputing Center in Wuxi. The results demonstrated that the parallel GND core based on grouping solution achieves good strong scalability and improves the performance significantly, as well as avoiding the SWOs

Multi-View Broad Learning System for Primate Oculomotor Decision Decoding

Multi-view learning improves the learning performance by utilizing multi-view data: data collected from multiple sources, or feature sets extracted from the same data source. This approach is suitable for primate brain state decoding using cortical neural signals. This is because the complementary components of simultaneously recorded neural signals, local field potentials (LFPs) and action potentials (spikes), can be treated as two views. In this paper, we extended broad learning system (BLS), a recently proposed wide neural network architecture, from single-view learning to multi-view learning, and validated its performance in decoding monkeys' oculomotor decision from medial frontal LFPs and spikes. We demonstrated that medial frontal LFPs and spikes in non-human primate do contain complementary information about the oculomotor decision, and that the proposed multi-view BLS is a more effective approach for decoding the oculomotor decision than several classical and state-of-the-art single-view and multi-view learning approaches

Application of immune clonal annealing algorithm for traffic diversion in traffic accident areas

To address the delayed adaptation of conventional traffic diversion methods in dynamic accident scenarios, this study proposes an immune clone annealing algorithm (ICAA)-based framework with three key innovations. First, a residual capacity analysis model is developed to pre-identify high-congestion-risk road sections (threshold: congestion probability CP ≥ 0.65) using directed graph theory, enabling proactive congestion management. Second, an enhanced support vector machine (SVM) classifier is introduced, integrating vehicle speed, density, and occupancy with cuckoo search optimization, achieving a congestion detection accuracy of 93.2%. Third, a throughput-maximizing objective function, resolved by the ICAA, is designed to optimize traffic flow redistribution. Simulation results under peak-hour accident conditions demonstrate that the proposed framework reduces average delays by 37.5% and reduces probability of congestion by 20%. These advancements highlight the framework’s robust adaptability in multi-accident scenarios, and make it a practical solution for real-time traffic management in complex urban networks

Effects of Rock Fragments on the Soil Physicochemical Properties and Vegetation on the Northeastern Tibetan Plateau

Stony soils are very widely distributed and contain abundant rock fragments (>2 mm), which impose major effects on soil properties and plant growth. However, the role of rock fragments is still often neglected, which can lead to an inadequate understanding of the interaction between plants and soil. Undisturbed soil columns were collected from three alpine grasslands on the Qilian Mountain, and the X-ray computed tomography method was applied to investigate the characteristics of rock fragments. The results showed there was significant difference in number density, volumetric content and surface area density of rock fragment among the three grasslands, and followed the order of alpine meadow > alpine steppe > alpine desert steppe. In addition, the soil organic carbon, total nitrogen, total phosphorus, available phosphorus, N-NH4+, and N-NO3− contents in fine earth all increased with increasing number density, volumetric content and surface area density but to different degrees. Furthermore, positive correlations were observed between the rock shape factor and belowground biomass (R2 = 0.531, p < 0.05), between the rock volumetric content and aboveground biomass (R2 = 0.527, p < 0.05), and between number density and Simpson’s index (R2 = 0.875, p < 0.05). Our findings suggest that within a certain range, the increase in rock fragment content is conducive to soil nutrient accumulation and soil water storage and circulation and changes plant features, which contributes to the growth of plants. In addition, rock fragments should be given more consideration when investigating the relationships between soil and vegetation and their response to climate change in future studies