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Task-Aware Flow Scheduling with Heterogeneous Utility Characteristics for Data Center Networks

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Tsinghua Science and Technology 2019年第4期24卷 400-411页

作者： fang dong Xiaolin Guo Pengcheng Zhou Dian Shen the School of Computer Science and Engineering Southeast University

With the continuous enrichment of cloud services, an increasing number of applications are being deployed in data centers. These emerging applications are often communication-intensive and data-parallel, and their performance is closely related to the underlying network. With their distributed nature, the applications consist of tasks that involve a collection of parallel flows. Traditional techniques to optimize flow-level metrics are agnostic to task-level requirements, leading to poor application-level performance. In this paper, we address the heterogeneous task-level requirements of applications and propose task-aware flow scheduling. First, we model tasks' sensitivity to their completion time by utilities. Second, on the basis of Nash bargaining theory, we establish a flow scheduling model with heterogeneous utility characteristics, and analyze it using Lagrange multiplier method and KKT condition. Third, we propose two utility-aware bandwidth allocation algorithms with different practical constraints. Finally, we present Tasch, a system that enables tasks to maintain high utilities and guarantees the fairness of utilities. To demonstrate the feasibility of our system, we conduct comprehensive evaluations with realworld traffic trace. Communication stages complete up to 1.4 faster on average, task utilities increase up to 2.26,and the fairness of tasks improves up to 8.66 using Tasch in comparison to per-flow mechanisms.

关键词： data center networks coflow flow scheduling data-intensive applications

State of health estimation for lithium-ion batteries in real-world electric vehicles

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Science China(Technological Sciences) 2023年第1期66卷 47-56页

作者： WU Ji fang LeiChao dong GuangZhong LIN MingQiang School of Automotive and Transportation Engineering Hefei University of TechnologyHefei 2300o9China Engineering Research Center for Intelligent Transportation and Cooperative Vehicle-Infrastructure of Anhui Province Hefei 230009China School of Mechanical Engineering and Automation Harbin Institute of TechnologyShenzhen 518055China Quanzhou Institute of Equipment Manufacturing Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesJinjiang362200China

The state of health(SOH) plays a significant role in the mileage and safety of an electric vehicle(EV). In recent years, many methods based on data-driven analysis and laboratory measurements have been developed for SOH estimation. However, most of these proposed methods cannot be applied to real-world EVs. Here, we present a method for SOH estimation based on realworld EV data. A battery-aging evaluation health index(HI) with a strong correlation to the SOH is retrieved from battery-aging data and then modified with thermal factors to depict the former SOH. Afterward, a local weighted linear-regression algorithm is used to qualitatively characterize the declining trend of the HI, which eliminates the local HI fluctuation caused by data ***, a series of features-of-interest(FOIs) is extracted according to the battery consistency, cell-voltage extrema, and cumulative mileage, and validated using the grey relational analysis. Finally, a battery-degradation model is built using the extreme gradient-boosting algorithm with the selected FOIs. The experimental results from real-world data indicate that the proposed method has high estimation accuracy and generalization, and the maximum error is around 2% for batteries in realworld EVs.

关键词： electric vehicle state of health extreme gradient boosting battery consistency

VirtCO:Joint Coflow Scheduling and Virtual Machine Placement in Cloud Data Centers

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Tsinghua Science and Technology 2019年第5期24卷 630-644页

作者： Dian Shen Junzhou Luo fang dong Junxue Zhang School of Computer Science and Engineering Southeast University Nanjing 211189 China University of Science and Technology Hong Kong 999077 China

Cloud data centers, such as Amazon EC2, host myriad big data applications using Virtual Machines(VMs). As these applications are communication-intensive, optimizing network transfer between VMs is critical to the performance of these applications and network utilization of data centers. Previous studies have addressed this issue by scheduling network flows with coflow semantics or optimizing VM placement with traffic ***, coflow scheduling and VM placement have been conducted orthogonally. In fact, these two mechanisms are mutually dependent, and optimizing these two complementary degrees of freedom independently turns out to be suboptimal. In this paper, we present VirtCO, a practical framework that jointly schedules coflows and places VMs ahead of VM launch to optimize the overall performance of data center applications. We model the joint coflow scheduling and VM placement optimization problem, and propose effective heuristics for solving it. We further implement VirtCO with OpenStack and deploy it in a testbed environment. Extensive evaluation of real-world traces shows that compared with state-of-the-art solutions, VirtCO greatly reduces the average coflow completion time by up to 36.5%. This new framework is also compatible with and readily deployable within existing data center architectures.

关键词： cloud computing data center coflow scheduling Virtual Machine (VM) placement

Super twisting sliding mode control for a flexible air-breathing hypersonic vehicle based on disturbance observer

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Science China(Information Sciences) 2015年第7期58卷 84-98页

作者： ZONG Qun dong Qi WANG fang TIAN BaiLing College of Electric Engineering and Automation Tianjin University School of Science Yanshan University

A robust finite time sliding mode control strategy is proposed in this paper for a flexible air-breathing hypersonic vehicle(FAHV) model with aerodynamic parameter uncertainty. The strong coupling among the aerodynamics, the propulsion system and the flexibility effects makes the problem more challenging. Firstly, to reduce the complexity of the controller design, the FAHV model is transformed into three subsystems(velocity subsystem, altitude and flight path angle subsystem, attack of angle and pitch rate subsystem). Secondly, based on super-twisting algorithm, a novel finite time disturbance observer and an improved sliding mode controller are designed to ensure the finite time stability of each subsystem. The proposed disturbance observer can estimate the uncertainty and the derivative of virtual control in finite time. Finally, simulation results are presented to show the precision and rapidness in tracking the reference trajectory and validate the effectiveness of the designed controller.

关键词： flexible air-breathing hypersonic vehicle(FAHV) disturbance observer sliding mode control super-twisting algorithm finite time s

Identification of massive molecular markers in Echinochloa phyllopogon using a restriction-site associated DNA approach

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Plant Diversity 2017年第5期39卷 287-293页

作者： Guoqi Chen Wei Zhang Jiapeng fang Liyao dong College of Plant Protection Nanjing Agricultural UniversityNanjing 210095China Key Laboratory of Integrated Pest Management on Crops in East China (Nanjing Agricultural University) Ministry of AgricultureNanjing 210095China

Echinochloa phyUopogon proliferation seriously threatens rice production worldwide. We combined a restriction-site associated DNA （RAD） approach with Illumina DNA sequencing for rapid and mass discovery of simple sequence repeat （SSR） and single nucleotide polymorphism （SNP） markers for E. phyllopogon. RAD tags were generated from the genomic DNA of two E. phyUopogon plants, and sequenced to produce 5197.7 Mb and 5242.9 Mb high quality sequences, respectively. The GC content of E. phyllopogon was 45.8%, which is high for monocots. In total, 4710 putative SSRs were identified in 4132 contigs, which permitted the design of PCR primers for E. phyllopogon. Most repeat motifs among the SSRs identified were dinucleotide （〉82%）, and most of these SSRs were four motif-repeats （〉75%）. The most frequent motif was AT, accounting for 36.3%-37.2%, followed by AG and AC. In total, 78 putative polymorphic SSR loci were found. A total of 49,179 SNPs were discovered between the two samples of E. phyllopogon, 67.1% of which were transversions and 32.9% were transitions. We used eight SSRs to study the genetic diversity of four E. phyllopogon populations collected from rice fields in China and all eight loci tested were polymorphic.

关键词： Echinochloa phyllopogon Polymorphic PAD sequencing SNPSSR

Thickness-Dependent Microstructure and its Effect on Anisotropic Mechanical Properties of Duplex Stainless Steel 2205 Multi-pass Welded Joints

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Acta Metallurgica Sinica(English Letters) 2023年第11期36卷 1883-1892页

作者： Zhilong dong Xue-fang Xie Jingwen Li Yu Wan State Key Laboratory of Heavy Oil Processing College of New EnergyChina University of Petroleum(East China)Qingdao266580China China National Offshore Oil Corporation Petrochemical Engineering Company Limited Jinan250000China

In this study,the thickness-dependent microstructural characteristics of duplex stainless steel 2205 multi-pass welded joints were first investigated by the combination of optical microscope and electron back-scattered diffraction ***,a series of tensile tests of miniature samples cut from different passes and directions were performed to analyze the thickness-dependent and anisotropic mechanical *** results demonstrate that the microstructure changed with the welded passes,i.e.,a large number of grain boundary austenite,Widmanstätten austenite and a small number of tiny intragranular austenite existed at the surface passes,while a mass of intragranular austenite were found at the middle ***,the Kurdjumov–Sachs orientation relationship was widespread at the welded *** addition,the yield and tensile strengths of the middle passes were greater than that of the surface passes due to the grain-boundary strengthening by tiny intragranular ***,due to the existence of Kurdjumov–Sachs orientation relationship,the longitudinal yield and tensile strength were greater than transverse values,particularly for the middle passes.

关键词： Duplex stainless steel Multi-pass welded joints Thickness-dependent microstructure Anisotropic mechanical properties

Impact of finite-range tensor terms in the Gogny force on theβ-decay of magic nuclei

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Nuclear Science and Techniques 2021年第7期32卷 83-89页

作者： Da-Zhuang Chen dong-Liang fang Chun-Lin Bai College of Physics Sichuan UniversityChengdu 610065China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China

Effects of finite-range tensor force onβ-decay of magic and semimagic nuclei of^(34)Si,^(68,78)Ni,and^(132)Sn have been investigated using the self-consistent Hartree–Fock plus random-phase approximation *** tensor force shifts the low-lying Gamow–Teller states downward and systematically improves the calculations of Q and logft ***,it systematically reduces the deviations between the theoretical and experimental data and significantly improves the calculation ofβ-decay *** effect is similar to that of zero-range tensor force.

关键词： tensor decay finite

Numerical study via total Lagrangian smoothed particle hydrodynamics on chip formation in micro cutting

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Advances in Manufacturing 2020年第2期8卷 144-159页

作者： Jin-Shi Wang Xiao-dong Zhang Feng-Zhou fang State Key Laboratory of Precision Measuring Technology and Instruments Centre of Micro/Nano Manufacturing Technology(MNMT)Tianjin UniversityTianjin 300072People's Republic of China Centre of Micro/Nano Manufacturing Technology(MNMT-Dublin) University College DublinDublinIreland

Numerical simulation is an effective approach in studying cutting *** widely used methods for cutting simulation include finite element analysis and molecular ***,there exist some intrinsic shortcomings when using a mesh-based formulation,and the capable scale of molecular dynamics is extremely *** contrast,smoothed particle hydrodynamics(SPH)is a candidate to combine the advantages of *** is a particle method which is suitable for simulating the large deformation process,and is formulated based on continuum mechanics so that large scale problems can be handled in *** a result,SPH has also become a main way for the cutting *** some issues arise while using conventional SPH to handle solid materials,the total Lagrangian smoothed particle hydrodynamics(TLSPH)is *** instabilities would still occur during the cutting,which is a critical issue to *** paper studies the effects of TLSPH settings and cutting model parameters on the numerical instability,as well as the chip formation *** deformation,stress field and cutting forces are analyzed as *** shows that the hourglass coefficient,critical pairwise deformation and time step are three important parameters to control the stability of the simulation,and a strategy on how to adjust them is provided.

关键词： Cutting Total Lagrangian smoothed particle hydrodynamics(TLSPH) Numerical instability Chip formation

Magnetic properties of sputtered anisotropic Pr–Fe–B thin films with different structures and antiferromagnetic materials

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Rare Metals 2016年第12期35卷 926-929页

作者： fang Yang Wei Liu Zhi-dong Zhang Shenyang National Laboratory for Materials Science Institute of Metal Research and International Centre for Materials PhysicsChinese Academy of Sciences Superconducting Materials Research Center Northwest Institute for Nonferrous Metal Research

Anisotropic Pr-Fe-B films with soft-magnetic layer （Fe） and/or antiferromagnetic layer （Mn, FeMn or MnO） were prepared by direct-current （DC） magnetron sputtering on Si （100） substrates heated at 650℃. The influence of four types＇ different structures on the magnetic properties of Pr-Fe-B films was investigated. The phase and magnetic properties were characterized by means of X-ray diffraction （XRD） and superconducting quantum interference device （SQUID）. Addition of anti-ferromagnetic layer enhances both the coercivity and the remanence ratios of Pr-Fe-B films with suitable structures. The interface number increases and the antiferromagnetic-ferromagnetic exchange interaction is likely to become stronger, which affect the improvement of magnetic properties. To further understand the influence of structures with soft-magnetic Fe layer and/or antifer- romagnetic FeMn layer on the magnetic properties of Pr-Fe-B hard-magnetic films, the thickness of Pr-Fe-B layer was designed to decrease from 600 to 50 nm. The improvement of magnetic properties becomes obvious in Mo（50 nm）/Pr-Fe-B（25 nm）Mo（2 nm）FeMn（20 nm）Mo （2 nm）Pr-Fe-B（25 nm）/Mo（50 rim） film.

关键词： Magnetic materials Thin films Coercivity Hysteresis loop Sputtering