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An efficient data layout scheme for better I/O balancing in RAID-6 storage systems

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Frontiers of Information Technology & Electronic Engineering 2015年第5期16卷 335-345页

作者： Ping xie Jian-zhong HUANG Er-wei DAI Qiang CAO chang-sheng xie Wuhan National Laboratory for Opto Electronics Huazhong University of Science & Technology Computer College Qinghai Normal University

Among redundant arrays of independent disks(RAID)-6 codes, maximum distance separable(MDS)based RAID-6 codes are popular because they have the optimal storage efficiency. Although vertical MDS codes exhibit better load balancing compared to horizontal MDS codes in partial stripes, an I/O unbalancing problem still exists in some vertical codes. To address this issue, we propose a novel efficient data layout, uniform P-code(UPC), to support highly balanced I/Os among P-coded disk arrays(i.e., PC). In UPC, the nonuniformly distributed information symbols in each parity chain of P-code are moved along their columns to other rows, thus enabling the parity chain to keep original parity relationships and tolerate double disk failures. The UPC scheme not only achieves optimal storage efficiency, computational complexity, and update complexity, but also supports better I/O balancing in the context of large-scale storage systems. We also conduct a performance study on reconstruction algorithms using an analytical model. Besides extensive theoretical analysis, comparative performance experiments are conducted by replaying real-world workloads under various configurations. Experimental results illustrate that our UPC scheme significantly outperforms the PC scheme in terms of average user response time. In particular, in the case of a 12-disk array, the UPC scheme can improve the access performance of the RAID-6 storage system by29.9% compared to the PC scheme.

关键词： RAID-6 Data availability High performance I/O balancing

Exploring optimal combination of a file system and an I/O scheduler for underlying solid state disks

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Journal of Zhejiang University-Science C(Computers and Electronics) 2014年第8期15卷 607-621页

作者： Hui SUN Xiao QIN chang-sheng xie National Laboratory for Optoelectronics and School of Science and Technology Huazhong University of Science and Technology Department of Computer Science and Software Engineering Auburn University

Performance and energy consumption of a solid state disk(SSD) highly depend on file systems and I/O schedulers in operating systems. To find an optimal combination of a file system and an I/O scheduler for SSDs, we use a metric called the aggregative indicator(AI), which is the ratio of SSD performance value(e.g., data transfer rate in MB/s or throughput in IOPS) to that of energy consumption for an SSD. This metric aims to evaluate SSD performance per energy consumption and to study the SSD which delivers high performance at low energy consumption in a combination of a file system and an I/O scheduler. We also propose a metric called Cemp to study the changes of energy consumption and mean performance for an Intel SSD(SSD-I) when it provides the largest AI, lowest power, and highest performance, respectively. Using Cemp, we attempt to find the combination of a file system and an I/O scheduler to make SSD-I deliver a smooth change in energy consumption. We employ Filebench as a workload generator to simulate a wide range of workloads(i.e., varmail, fileserver, and webserver), and explore optimal combinations of file systems and I/O schedulers(i.e., optimal values of AI) for tested SSDs under different workloads. Experimental results reveal that the proposed aggregative indicator is comprehensive for exploring the optimal combination of a file system and an I/O scheduler for SSDs, compared with an individual metric.

关键词： Solid state disk(SSD) Performance Energy consumption File system I/O scheduler

Effects of Aromatherapy on Physical and Mental Health of Cancer Patients Undergoing Radiotherapy and/or Chemotherapy: A Meta-Analysis

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Chinese Journal of Integrative Medicine 2024年第5期30卷 449-457页

作者： xie Shuang-ran MA Liang XU Xin-yu ZHOU Shu xie Hui-miao xie chang-sheng The First Clinical Medical College Zhejiang Chinese Medical UniversityHangzhou 310053China Department of Medical Oncology Hangzhou Traditional Chinese Medicine Hospital Affiliated to Zhejiang Chinese Medical UniversityHangzhou 310007China Department of Dermatology the Third Xiangya HospitalCentral South UniversityChangsha 410013China Department of Famous Chinese Medicine Clinic the Second Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhou 310005China Department of Medical Oncology the First Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhou 310006China

Backgroup:Currently,aromatherapy is being increasingly utilized in clinical practice,particularly in managing the side effects associated with radiotherapy and ***,it remains to be established whether aromatherapy can effectively alleviate these ***:To investigate the effects of aromatherapy on the physical and mental health of patients with cancer undergoing radiotherapy and ***:Seven databases were researched from inception until September 29,2023,including PubMed,Scopus,and Web of Science,Chinese National Knowledge Infrastructure,Wanfang database,China Biology Medicine disc and VIP Chinese Medical Journal *** Manager version 5.3 was utilized for data *** Cochrane Risk of Bias tool RoB2 was employed to evaluate the quality of the literature included in the *** quality rating was assessed using the Grading of Recommendations Assessment,Development,and Evaluation(GRADE) approach through the GRADEpro GDT online ***:Nineteen studies involving 1,541 patients were *** can alleviate nausea [relative risk(RR)=0.64,95% confidence interval(CI):0.53 to 0.78,P<0.05,I^(2)=46%;standardized mean difference(SMD)=-0.86,95% CI:-1.21 to-0.51,P<0.05,I^(2)=64%] and vomiting(RR=0.54,95% CI:0.42 to 0.69,P<0.05,I^(2)=35%;SMD=-1.28,95% CI:-1.52 to-1.03,P<0.05,I^(2)=92%),improve sleep disorders [mean difference(MD)=-3.39,95% CI:-3.95 to-2.84,P<0.05,I^(2)=0%],relieve pain(SMD=-1.58,95% CI:-1.96 to-1.21,P<0.05,I^(2)=0%),mitigate fatigue(SMD=-1.28,95% CI:-2.44 to-0.11,P<0.05,I^(2)=93%) and enhance quality of life(SMD=0.50,95% CI:0.22 to 0.79,P<0.05,I^(2)=0%) in cancer patients after radiotherapy and chemotherapy,but it may not have a significant effect on *** risk of bias was high in the included studies using the Cochrane Risk of Bias tool RoB2,and no studies were considered to be of high grade according to the GRADE ***:Aromatherapy is an efficacious,safe a

关键词： aromatherapy cancer chemoradiotherapy physical psychological

Optimizing storage performance in public cloud platforms

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第12期12卷 951-964页

作者： Jian-zong WANG Peter VARMAN chang-sheng xie School of Computer Science and Technology Huazhong University of Science and Technology Wuhan 430074 China Wuhan National Laboratory for Optoelectronics Wuhan 430074 China Department of Electrical and Computer Engineering Rice University Houston 77005 USA

Cloud computing is an elastic computing model where users can lease computing and storage resources on demand from a remote infrastructure. It is gaining popularity due to its low cost, high reliability, and wide availability. With the emergence of public cloud storage platforms like Amazon, Microsoft, and Google, individual applications and enterprise storage are being deployed on Clouds. However, a serious impediment to its wider deployment is the relative lack of effective data management services. Our experiments, as well as industry reports, have shown that the performance and service-level agreement (SLA) cannot be guaranteed when the data is served over public Clouds. The relatively slow access to persistent data and large variability in cloud storage I/O performance can significantly degrade the performance of data-intensive applications. This paper addresses the issue of I/O performance fluctuation over public cloud platforms and we propose a middleware called CloudMW between the Cloud storage and clients to provide the storage services with better performance and SLA satisfaction. Some technologies, including data virtualization, data chunking, caching, and replication, are integrated into CloudMW to achieve a more stable and predictable performance, and permit flexible sharing of storage among the virtual machines (VMs). Experimental results based on Amazon Web Services (AWS) show that CloudMW is able to improve the stability and help provide better SLAs and data sharing for cloud storage.

关键词： Cloud storage Performance fluctuation Middleware Service-level agreement

Optimization of turbine cold-end system based on BP neural network and genetic algorithm

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Frontiers in Energy 2014年第4期8卷 459-463页

作者： chang CHEN Danmei xie Yangheng XIONG Hengliang ZHANG School of Power and Mechanical Engineering Wuhan University Wuhan 430072 China

The operation condition of the cold-end system of a steam turbine has a direct impact on the economy and security of the unit as it is an indispensible auxiliary system of the thermal power unit. Many factors influence the cold- end operation of a steam turbine; therefore, the operation mode needs to be optimized. The optimization analysis of a 1000 MW ultra-supercritical （USC） unit, the turbine cold- end system, was performed utilizing the back propagation （BP） neural network method with genetic algorithm （GA） optimization analysis. The optimized condenser pressure under different conditions was obtained, and it turned out that the optimized parameters were of significance to the performance and economic operation of the system.

关键词： optimization turbine cold-end system BP neural network genetic algorithm

Score Tests for Zero-inflated Double Poisson Regression Models

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Acta Mathematicae Applicatae Sinica 2017年第4期33卷 851-864页

作者： Feng-chang xie Jin-guan LIN Bo-cheng WEI School of Mathematical Sciences Nanjing Normal University Department of Statistics Nanjing Audit University Department of Mathematics Southeast University

Count data with excess zeros encountered in many applications often exhibit extra variation. There- fore, zero-inflated Poisson （ZIP） model may fail to fit such data. In this paper, a zero-inflated double Poisson model （ZIDP）, which is generalization of the ZIP model, is studied and the score tests for the significance of dis- persion and zero-inflation in ZIDP model are developed. Meanwhile, this work also develops homogeneous tests for dispersion and/or zero-inflation parameter, and corresponding score test statistics are obtained. One numer- ical example is given to illustrate our methodology and the properties of score test statistics are investigated through Monte Carlo simulations.

关键词： double Poisson zero-inflation dispersion score test test of homogeneity

Static recrystallization behavior of SA508Gr.4N reactor pressure vessel steel during hot compressive deformation

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Journal of Iron and Steel Research International 2021年第5期28卷 604-612页

作者： Shi-bin Qiao Xi-kou He chang-sheng xie Zheng-dong Liu Institute for Special Steels Central Iron and Steel Research InstituteBeijing 100081China Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing 100083China

The two-pass isothermal hot compression method was used to study the effect of different thermal deformation conditions on static recrystallization behavior in Ni-Cr-Mo series SA508Gr.4N low alloy steel with interval holding time ranging from 1 to 300 s,temperature ranging from 950 to 1150℃,strain rate ranging from 0.01 to 1 s^(-1),true strains ranging from 0.1 to 0.2,and initial austenite grain size ranging from 175 to 552μ*** can be concluded that the static recrystallization volume fraction gradually increases with the increase in the deformation temperature,strain rate,strain and pass interval,and the decrease in the initial grain size,which is mainly due to the increase in the deformation energy storage and ***,strain-induced grain boundary migration is the nucleation mechanism for static recrystallization of SA508Gr.4N low alloy *** on the stress-strain curve,the predicted value obtained from the established static recrystallization kinetics model is in good consistence with the experimental value,and the static recrystallization thermal activation energy of SA508Gr.4N steel was calculated as 264,225.99 J/mol.

关键词： Nuclear reactor pressure vessel Two-pass isothermal thermal compression Static recrystallization Kinetics model

Metadynamic recrystallization behaviors of SA508Gr.4N reactor pressure vessel steel during hot compressive deformation

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Journal of Iron and Steel Research International 2021年第1期28卷 46-57页

作者： Shi-bin Qiao Zheng-dong Liu Xi-kou He chang-sheng xie Institute for Special Steels Central Iron and Steel Research InstituteBeijing 100081China Collaborative Innovation Centre of Steel Technology University of Science and Technology BeijingBeijing 100083China

The metadynamic recrystallization(MDRX)model is established,and the coefficients determined by multiple linear regression analysis are used to describe the microstructure evolution of SA508Gr.4N *** effects of compression temperature of 950–1150℃,strain rate of 0.001–0.1 s^(-1),pre-strain of 0.3–0.6,initial austenite grain size(IAGS)of 136–552 lm,and interval time of 1–300 s on the MDRX kinetics and microstructure evolution were analyzed,using twopass compression test method on Gleeble thermo-mechanical *** results show that MDRX kinetics and austenite grain size are strongly dependent on compression temperature and strain rate,MDRX volume fraction increases with increasing compression temperature and strain rate,and the grain size decreases with increasing strain rate and decreasing compression temperature,while less affected by the pre-strain and ***,the values predicted using MDRX model and the ones calculated from experiment are compared,and the results show that the proposed model can give a reasonable estimate of MDRX behavior for SA508Gr.4N steel.

关键词： SA508Gr.4N steel Metadynamic recrystallization Kinetic model Grain size model

Experimental Investigation of the Resistance Performance and Heave and Pitch Motions of Ice-Going Container Ship Under Pack Ice Conditions

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China Ocean Engineering 2018年第2期32卷 169-178页

作者： GUO Chun-yu xie chang ZHANG Jin-zhao WANG Shuai ZHAO Da-gang College of Shipbuilding Engineering Harbin Engineering UniversityHarbin 150001China Nantong COSCO KHI Ship Engineering Co.Ltd Nantong 226005China Shanghai Marine Equipment Research Institute Shanghai 200031China

In order to analyze the ice-going ship’s performance under the pack ice conditions, synthetic ice was introduced into a towing tank. A barrier using floating cylinder in the towing tank was designed to carry out the resistance experiment. The test results indicated that the encountering frequency between the ship model and the pack ice shifts towards a high-velocity point as the concentration of the pack ice increases, and this encountering frequency creates an unstable region of the resistance, and the unstable region shifts to the higher speed with the increasing concentration. The results also showed that for the same speed points, the ratio of the pack ice resistance to the open water resistance increases with the increasing concentration, and for the same concentrations, this ratio decreases as the speed increases. Motion characteristics showed that the mean value of the heave motion increases as the speed increases, and the pitch motion tends to increase with the increasing speed. In addition, the total resistance of the fullscale was predicted.

关键词： synthetic ice pack ice concentration heave pitch peak collision value