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Resource abstraction and data placement for distributed hybrid memory pool

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Frontiers of Computer Science 2021年第3期15卷 47-57页

作者： Tingting CHEN haikun liu Xiaofei LIAO Hai JIN National Engineering Research Center for Big Data Technology and System Services Computing Technology and System Lab/Gluster and Grid Computing LabSchool of Gomputing Science and TechnologyHuazhong University of Science and TechnologyWuhan 430074China

Emerging byte-addressable non-volatile memory(NVM)technologies offer higher density and lower cost than DRAM,at the expense of lower performance and limited write *** have been many studies on hybrid NVM/DRAM memory management in a single physical ***,it is still an open problem on how to manage hybrid memories efficiently in a distributed *** paper proposes Alloy,a memory resource abstraction and data placement strategy for an RDMA-enabled distributed hybrid memory pool(DHMP).Alloy provides simple APIs for applications to utilize DRAM or NVM resource in the DHMP,without being aware of the hardware details of the *** propose a hotness-aware data placement scheme,which combines hot data migration,data replication and write merging together to improve application performance and reduce the cost of *** evaluate Alloy with several micro-benchmark workloads and public benchmark *** results show that Alloy can significantly reduce the DRAM usage in the DHMP by up to 95%,while reducing the total memory access time by up to 57%compared with the state-of-the-art approaches.

关键词： load balance distributed hybrid memory clouds

UCat: heterogeneous memory management for unikernels

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Frontiers of Computer Science 2023年第1期17卷 51-61页

作者： Chong TIAN haikun liu Xiaofei LIAO Hai JIN National Engineering Research Center for Big Data Technology and System Services Computing Technology and System Lab/Cluster and Grid Computing LabSchool of Computing Science and TechnologyHuazhong University of Science and TechnologyWuhan 430074China

Unikernels provide an efficient and lightweight way to deploy cloud computing services in application-specialized and single-address-space virtual machines (VMs). They can efficiently deploy hundreds of unikernel-based VMs in a single physical server. In such a cloud computing platform, main memory is the primary bottleneck resource for high-density application deployment. Recently, non-volatile memory (NVM) technologies has become increasingly popular in cloud data centers because they can offer extremely large memory capacity at a low expense. However, there still remain many challenges to utilize NVMs for unikernel-based VMs, such as the difficulty of heterogeneous memory allocation and high performance overhead of address *** this paper, we present UCat, a heterogeneous memory management mechanism that support multi-grained memory allocation for unikernels. We propose front-end/back-end cooperative address space mapping to expose the host memory heterogeneity to unikernels. UCat exploits large pages to reduce the cost of two-layer address translation in virtualization environments, and leverages slab allocation to reduce memory waste due to internal memory fragmentation. We implement UCat based on a popular unikernel--OSv and conduct extensive experiments to evaluate its efficiency. Experimental results show that UCat can reduce the memory consumption of unikernels by 50% and TLB miss rate by 41%, and improve the throughput of real-world benchmarks such as memslap and YCSB by up to 18.5% and 14.8%, respectively.

关键词： unikernel virtualization non-volatile memory heterogeneous memory large page slab allocation

A hybrid memory architecture supporting fine-grained data migration

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Frontiers of Computer Science 2024年第2期18卷 31-41页

作者： Ye CHI Jianhui YUE Xiaofei LIAO haikun liu Hai JIN National Engineering Research Center for Big Data Technology and System Services Computing Technology and System LabCluster and Grid Computing LabSchool of Computer Science and TechnologyHuazhong University of Science and TechnologyWuhan 430074China Department of Computer Science Michigan Technological UniversityMichigan 49931USA

Hybrid memory systems composed of dynamic random access memory(DRAM)and Non-volatile memory(NVM)often exploit page migration technologies to fully take the advantages of different memory *** previous proposals usually migrate data at a granularity of 4 KB pages,and thus waste memory bandwidth and DRAM *** this paper,we propose Mocha,a non-hierarchical architecture that organizes DRAM and NVM in a flat address space physically,but manages them in a cache/memory *** the commercial NVM device-Intel Optane DC Persistent Memory Modules(DCPMM)actually access the physical media at a granularity of 256 bytes(an Optane block),we manage the DRAM cache at the 256-byte size to adapt to this feature of *** design not only enables fine-grained data migration and management for the DRAM cache,but also avoids write amplification for Intel Optane *** also create an Indirect Address Cache(IAC)in Hybrid Memory Controller(HMC)and propose a reverse address mapping table in the DRAM to speed up address translation and cache ***,we exploit a utility-based caching mechanism to filter cold blocks in the NVM,and further improve the efficiency of the DRAM *** implement Mocha in an architectural *** results show that Mocha can improve application performance by 8.2%on average(up to 24.6%),reduce 6.9%energy consumption and 25.9%data migration traffic on average,compared with a typical hybrid memory architecture-HSCC.

关键词： non-volatile memory hybrid memory system data migration fine-grained caching

Influence of dysprosium concentration on sensitivity of luminescent thermometers of phosphors Ca_(9)Tb(PO_(4))_(5)(SiO_(4))F_(2)

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Journal of Rare Earths 2021年第8期39卷 946-951页

作者： Jingxue Zhang Lefu Mei Yuanyuan Zhang Qingfeng Guo Libing Liao haikun liu Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes National Laboratory of Mineral MaterialsSchool of Materials Science and TechnologyChina University of GeosciencesBeijing 100083China School of Materials Science and Engineering Dongguan University of TechnologyDongguan 523808China School of Gemmology China University of GeosciencesBeijing 100083China School of Chemical Engineering and Energy Technology Dongguan University of TechnologyDongguan 523808China

Tb^(3+),Dy^(3+)-co-doped Ca_(9)Tb_(x)Dy_(1-x)(PO_(4))_(5)(SiO_(4))F_(2) phosphors were prepared via high-temperature solidphase reaction method and the potential application in optical temperature measurements due to their color-tunable property was investigated in *** photoluminescence emission(PL) and photoluminescence excitation(PLE) spectra results show that the as-prepared phosphors exhibit both Tb^(3+) and Dy^(3+) emissions at 546 nm(^(5)D_(4)-^(7)F_(5) transition of Tb^(3+)) and 587 nm(^(4)F_(9/2)-^(6)H_(13/2) transition of Dy^(3+)) upon 376 nm excitation,*** addition,the fluorescence decay analysis shows that the lifetime of the Tb3+emission rapidly decreases,which confirms the energy transfer existence between Dy^(3+) and Tb^(3+).Under 376 nm excitation,the temperature dependence of the fluorescence intensity ratios for the dualmission bands peaked at 546 and 587 nm was studied in the temperature range from 303 to 573 *** results show that with the increase of Dy^(3+) concentration,the relative sensitivity first increases and then decreases,what’s more,the maximum relative sensitivity is 3.142×10^(-3)%/K for Ca_(9)Tb_(x)Dy_(1-x)(PO_(4))_(5)(SiO_(4))F_(2)(x=0.4).As a consequence,this preliminary study provides a novel method for exploring the novel thermo meters.

关键词： Temperature measurement Apatite Fluorescence intensity ratios Phosphor Thermometers Rare earths

Structure and luminescence properties of color-tunable phosphor Sr_(2)La_(3)(SiO_(4))_(3)F:Tb^(3+),Sm^(3+)

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Journal of Rare Earths 2023年第9期41卷 1288-1294,I0001页

作者： haikun liu Kun Nie Yuanyuan Zhang Lefu Mei Dina V.Deyneko Xiaoxue Ma Department of Energy and Chemical Engineering Dongguan University of TechnologyDongguan 523808China State Key Laboratory of New Textile Materials&Advanced Processing Technology and Hubei Key Laboratory for New Textile Materials and Applications School of Materials Science and EngineeringKey Laboratory of Polyphenylene Sulfide Fiber and Application in Textile IndustryWuhan Textile UniversityWuhan430200China Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes National Laboratory of Mineral MaterialsSchool of Materials Sciences and TechnologyChina University of GeosciencesBeijing 100083China School of Materials Sciences and Technology Dongguan University of TechnologyDongguan 523808China School of Materials Science and Engineering Xi'an Jiaotong UniversityXi'an 710049China Department of Chemistry Lomonosov Moscow State UniversityMoscow 119991Russia Laboratory of Arctic Mineralogy and Material Sciences Kola Science CentreRussian Academy of Sciences14 Fersman Str.184209ApatityRussia

A series of single-phase and color-tunable phosphors Sr_(2)La_(3)(SiO_(4))_(3)F:0.15Tb^(3+),xSm^(3+)(SLSOF:0.15Tb^(3+),xSm^(3+)) was prepared using solid-state *** X-ray diffraction(XRD) was used to characterize the phase of the as-prepared *** synthesized phosphors have apatite-type structure without other ***^(3+) and Tb^(3+) ions substitute La^(3+) into the lattice and form a single-phase solid *** elements are evenly distributed in the sample according to the scanning electron microscopy(SEM) *** crystal structure of the host phosphor was refined by the Rietveld *** optical properties were studied in detail by investigation of the luminescence and diffuse spectra,fluorescence decay curves and energy transfer *** phosphor color can be changed from green(0.29,0.48) to yellow/orange and red(0.57,0.42) via adjusting the doping ratio of Sm^(3+).The SLSOF:0.15Tb^(3+),xSm^(3+)phosphors can emit typical multicolor light such as green,yellow,orange and red with gradually increasing Sm^(3+)doping *** results indicate the occurrence of the energy transfer which results in the color-tunable properties of the phosphors.

关键词： Apatite Calcination Phosphor Optical property Luminescence Rare earths

Effective regulation of electronic structures and luminescence properties of LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):Dy^(3+)phosphors by tetrahedral substitution

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Journal of Rare Earths 2023年第5期41卷 673-681,I0002页

作者： Yuanyuan Zhang Lefu Mei haikun liu Sergey M.Aksenov Dina V.Deyneko Deliang Chen School of Materials Sciences and Technology Dongguan University of TechnologyDongguan 523808China School of Materials Science and Engineering Xi'an Jiaotong UniversityXi'an 710049China Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes National Laboratory of Mineral MaterialsSchool of Materials Sciences and TechnologyChina University of GeosciencesBeijing 100083China Department of Energy and Chemical Engineering Dongguan University of TechnologyDongguan 523808China Laboratory of Arctic Mineralogy and Material Sciences Kola Science CentreRussian Academy of Sciences14 Fersman StrApatity184209Russia Laboratory of Nature-Inspired Technologies and Environmental Safety of the Arctic Kola Science CentreRussian Academy of SciencesApatity18420 Russia Department of Chemistry Lomonosov Moscow State UniversityMoscow119991Russia School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China

A series of Dy^(3+)-activated phosphors with the general formula LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):Dy^(3+)(0≤x≤3)characterized by an apatite-type structure were successfully synthesized via a simple solid-state technique involving a partial substitution of[SiO_(4)]^(4-)with[GeO_(4)]^(4-)*** effects of homovalent[GeO_(4)]^(4-)-[SiO_(4)]^(4-)substitution on the crystal structure,electronic structure,luminescence properties and thermal performance of LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):Dy^(3+)phosphors were studied in *** phases and microstructure were performed by using X-ray diffraction(XRD)Rietveld refinement method and scanning electron microscopy(SEM)*** substitution of smaller[SiO_(4)]^(4-)ions by larger[GeO_(4)]^(4-)ones makes their unit cell parameters increase gradually,and their band gaps *** photoluminescence spectra of LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):Dy^(3+)(0≤x≤3)exhibit obvious emission peaks located at 477,573 and 675 nm within a visible wavelength region,resulting in an excellent white ***,the I573nm/I477nm values of LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):Dy^(3+)(0≤x≤3)become larger with the partial substitution of[SiO_(4)]^(4-)by[GeO_(4)]^(4-),and their CIE chromaticity coordinates exhibit a yellow shift.

关键词： Apatite Structure substitution Electronic structure White emitting Rare earths

Habitat heterogeneity and biotic interactions mediate climate influences on seedling survival in a temperate forest

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Forest Ecosystems 2023年第5期10卷 579-588页

作者： haikun liu Hang Shi Quan Zhou Man Hu Xiao Shu Kerong Zhang Quanfa Zhang Haishan Dang Key Laboratory of Aquatic Botany and Watershed Ecology Wuhan Botanical GardenChinese Academy of SciencesWuhan430074China University of Chinese Academy of Sciences Beijing100049China

Seedling stage has long been recognized as the bottleneck of forest regeneration,and the biotic and abiotic processes that dominate at seedling stage largely affect the dynamics of *** might be particularly vulnerable to climate stress,so elucidating the role of interannual climate variation in fostering community dynamics is crucial to understanding the response of forest to climate *** seedling survival data of 69 woody species collected for five consecutive years from a 25-ha permanent plot in a temperate deciduous forest,we identified the effects of biotic interactions and habitat factors on seedling survival,and examined how those effects changed over *** found that interannual climate variations,followed by biotic interactions and habitat conditions,were the most significant predictors of seedling *** light showed a positive impact on seedling mortality,and seedling survival responded differently to soil and air *** of conspecific neighbor density were significantly strengthened with the increase of maximum air temperature and vapor pressure deficits in the growing season,but were weakened by increased maximum soil temperature and precipitation in the non-growing ***,seedling survival was strongly correlated with interannual climate variability at all life stages,and the strength of the correlation increased with seedling *** addition,the importance of biotic and abiotic factors on seedling survival differed significantly among species-trait ***,the neighborhood-mediated effects on mortality might be significantly contributing or even inverting the direct effects of varying abiotic conditions on seedling survival,and density-dependent effects could not be the only important factor influencing seedling survival at an early stage.

关键词： Seedling survival Extreme interannual climate Negative density-dependence Species coexistence

Exploration of single Fe atom supported on anatase TiO_(2)(001)for methane oxidation:A DFT study

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ChemPhysMater 2023年第1期2卷 90-96页

作者： Tianyi Wang haikun liu Ani Dong Rosalie Hocking Chenghua Sun Department of Chemistry and Biotechnology and Centre for Translational Atomaterials School of ScienceSwinburne University of TechnologyHawthornVIC 3122Australia School of Chemical Engineering and Energy Technology Dongguan University of TechnologyDongguan 523808China Department of Computer and Information Science City College of Dongguan University of TechnologyDongguan 523419China

Partial oxidation of methane is a promising alternative strategy for methanol production under mild reaction conditions;however,significant challenges hinder the development of appropriate *** this study,based on first-principles calculations,we demonstrate that a single Fe atom supported on anatase TiO_(2)(001)provides double active sites(Fe and Ti_(5C))to activate gas-phase O_(2)and form O-assisted *** triple state Fe-O/TiO_(2)(001)system exhibited better activity for methane activation(ΔG max=1.02 eV).Our findings offer new insights into the design of non-noble-3 d transition metal single-atom catalysts on TiO_(2)(001)for partial methane oxidation via an inexpensive O_(2)oxidant under mild reaction conditions.

关键词： Partial CH_(4)oxidation CH_(3)OH synthesis DFT Single atom catalyst Fe_(1)/TiO_(2)(001)

Disparities in tree mortality among plant functional types(PFTs)in a temperate forest:Insights into size-dependent and PFT-specific patterns

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Forest Ecosystems 2024年第4期11卷 480-490页

作者： Man Hu Hang Shi Rui He Bingbin Wen haikun liu Kerong Zhang Xiao Shu Haishan Dang Quanfa Zhang Key Laboratory of Aquatic Botany and Watershed Ecology Wuhan Botanical GardenChinese Academy of SciencesWuhan 430074China Danjiangkou Wetland Ecosystem Field Scientific Observation and Research Station Chinese Academy of Sciences&Hubei ProvinceWuhan 430074China University of Chinese Academy of Sciences Beijing 100049China Forest&Nature Lab Department of EnvironmentGhent UniversityGeraardsbergsesteenweg 267Melle-Gontrode9090Belgium

Tree mortality significantly influences forest structure and function,yet our understanding of its dynamic patterns among a range of tree sizes and among different plant functional types(PFTs)remains *** study analysed size-dependent tree mortality in a temperate forest,encompassing 46 tree species and 32,565 individuals across different PFTs(i.e.,evergreen conifer *** broadleaf species,shade-tolerant ***-intolerant species).By employing all-subset regression procedures and logistic generalized linear mixed-effects models,we identified distinct mortality patterns influenced by biotic and abiotic *** results showed a stable mortality patte rn in eve rgreen conifer species,contrasted by a declining pattern in deciduous broadleaf and shadetolerant,as well as shade-intolerant species,across size *** contribution to tree mortality of evergreen conifer species shifted from abiotic to biotic factors with increasing size,while the mortality of deciduous broadleaf species was mainly influenced by biotic factors,such as initial diameter at breast height(DBH)and conspecific negative *** shade-tolerant species,the mortality of small individuals was mainly determined by initial DBH and conspecific negative density dependence,whereas the mortality of large individuals was subjected to the combined effect of biotic(competition from neighbours)and abiotic factors(i.e.,convexity and pH).As for shade-intolerant species,competition from neighbours was found to be the main driver of tree mortality throughout their growth ***,these insights enhance our understanding of forest dynamics by revealing the size-dependent and PFT-specific tree mortality patterns,which may inform strategies for maintaining forest diversity and resilience in temperate forest ecosystems.

关键词： Size-dependent tree mortality Plant functional type Neighbourhood competition Topography variables Soil properties