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并行网络文件系统PNFS性能评测与分析 被引量:2
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作者 张媛 于冠龙 +1 位作者 卢泽新 刘亚萍 《计算机工程与应用》 CSCD 北大核心 2009年第35期65-69,共5页
传统的网络文件系统难以满足高性能计算系统的I/O需求,并行网络文件系统——PNFS可以有效地解决传统网络文件系统在可扩展性、可用性和性能上存在的问题。首先对PNFS的体系结构进行了设计,实现了元数据服务器与存储服务器的分离,消除了... 传统的网络文件系统难以满足高性能计算系统的I/O需求,并行网络文件系统——PNFS可以有效地解决传统网络文件系统在可扩展性、可用性和性能上存在的问题。首先对PNFS的体系结构进行了设计,实现了元数据服务器与存储服务器的分离,消除了由于集中服务器结构引发的I/O瓶颈问题。然后,对PNFS的原型系统进行了性能测试,并与相同环境下NFS的测试结果进行比较与分析,结果表明PNFS能够为客户端提供并行访问文件数据的能力,有着较高的I/O读写带宽和较低的访问延迟,同时实现了客户端I/O带宽与存储服务器规模之间的线性可扩展关系,能较好地满足高性能计算中的I/O需求。 展开更多
关键词 并行网络文件系统(Pnfs) 网络文件系统(nfs) 并行文件系统 性能测试
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Localization for mixed near-field and far-field sources under impulsive noise
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作者 GAO Hongyuan ZHANG Yuze +2 位作者 DU Ya’nan CHENG Jianhua CHEN Menghan 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2024年第2期302-315,共14页
In order to solve the problem that the performance of traditional localization methods for mixed near-field sources(NFSs)and far-field sources(FFSs)degrades under impulsive noise,a robust and novel localization method... In order to solve the problem that the performance of traditional localization methods for mixed near-field sources(NFSs)and far-field sources(FFSs)degrades under impulsive noise,a robust and novel localization method is proposed.After eliminating the impacts of impulsive noise by the weighted out-lier filter,the direction of arrivals(DOAs)of FFSs can be estimated by multiple signal classification(MUSIC)spectral peaks search.Based on the DOAs information of FFSs,the separation of mixed sources can be performed.Finally,the estimation of localizing parameters of NFSs can avoid two-dimension spectral peaks search by decomposing steering vectors.The Cramer-Rao bounds(CRB)for the unbiased estimations of DOA and range under impulsive noise have been drawn.Simulation experiments verify that the proposed method has advantages in probability of successful estimation(PSE)and root mean square error(RMSE)compared with existing localization methods.It can be concluded that the proposed method is effective and reliable in the environment with low generalized signal to noise ratio(GSNR),few snapshots,and strong impulse. 展开更多
关键词 source localization far-field source(nfs) near-field source(FFS) impulsive noise Cramer-Rao bound(CRB)
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iSCSI与NFS的协议开销对比 被引量:9
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作者 王冬 王超 +1 位作者 韩永 肖卓 《计算机工程与应用》 CSCD 2012年第36期105-111,163,共8页
随着IP网络存储体系的发展,iSCSI和NFS协议在局域网环境中的应用越来越广泛。实验性地比较iSCSI和NFS的性能,在具体硬件环境中分析了iSCSI initiator和NFS server读写进程的系统开销。对依附iSCSI存储的NFS服务器中的数据转发过程进行测... 随着IP网络存储体系的发展,iSCSI和NFS协议在局域网环境中的应用越来越广泛。实验性地比较iSCSI和NFS的性能,在具体硬件环境中分析了iSCSI initiator和NFS server读写进程的系统开销。对依附iSCSI存储的NFS服务器中的数据转发过程进行测试,综合考虑网络传输、异步读写以及工作流等因素产生的影响。实验结果显示,根据不同的请求数据大小以及读写比例,两者的系统开销比率也随之变化。因此,依附iSCSI存储的NFS服务器应该根据以上因素合理调整资源分配,从而获得良好的存储系统性能。 展开更多
关键词 网络文件系统(nfs) Internet小型计算机系统接口(iSCSI) 协议开销 时钟周期 数据传递服务器 数据转发
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多核下基于远程直接内存访问的高效远程过程调用研究
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作者 李波 孟丹 霍志刚 《高技术通讯》 CAS CSCD 北大核心 2011年第7期681-686,共6页
针对目前基于远程直接内存访问(RDMA)的远程过程调用(RPC)设计在多核背景下存在的性能和扩展性问题,提出了一种新的基于RDMAWrite的高效RPC设计方法并对网络文件系统(NFS)提供了支持。重点就设计中的安全性问题和内存管理机制进... 针对目前基于远程直接内存访问(RDMA)的远程过程调用(RPC)设计在多核背景下存在的性能和扩展性问题,提出了一种新的基于RDMAWrite的高效RPC设计方法并对网络文件系统(NFS)提供了支持。重点就设计中的安全性问题和内存管理机制进行了分析,并针对内存有效利用提出了被动和主动两种回收机制。测试结果表明,这种新的RPC设计方法能降低RPC延迟13%~20%。对内存文件系统及真实磁盘文件系统的测试表明,此设计能有效提高多核系统中RPC的性能和扩展性。 展开更多
关键词 远程直接内存访问(RDMA) 远程过程调用(RPC) 多核 网络文件系统(nfs)
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综合模块化航空电子系统远程加载技术研究及性能分析 被引量:3
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作者 崔明明 《航空电子技术》 2016年第4期19-22,共4页
随着飞机航空电子系统综合化程度的提高,软件的部署、加载和更新的复杂度也在逐步提高。传统软件更新后,需要在地面为每个模块进行升级,并将新版本的软件映像文件固化在模块上,这种更新周期长且流程复杂。随着通用模块和应用重构的发展... 随着飞机航空电子系统综合化程度的提高,软件的部署、加载和更新的复杂度也在逐步提高。传统软件更新后,需要在地面为每个模块进行升级,并将新版本的软件映像文件固化在模块上,这种更新周期长且流程复杂。随着通用模块和应用重构的发展,软件映像需要部署在系统的各个冗余备份节点中,从而使其更新的流程更为复杂。本文针对以上问题提出了基于光纤通道和ARINC653操作系统的远程数据加载系统,以使系统在上电、重启及重构时可实现从大容量存储模块上远程加载操作系统内核映像、分区应用及自启动功能。在功能实现的基础上,本文对远程加载和本地加载的时间性能进行了分析和比较。 展开更多
关键词 综合模块化航空电子(IMA) 光纤通道(FC) 网络文件系统(nfs)
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SnO_(2)/Co_(3)O_(4)nanofibers using double jets electrospinning as low operating temperature gas sensor 被引量:1
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作者 王昭 范树兴 唐伟 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第2期618-625,共8页
SnO_(2)/Co_(3)O_(4)nanofibers(NFs)are synthesized by using a homopolar electrospinning system with double jets of positive polarity electric fields.The morphology and structure of SnO_(2)/Co_(3)O_(4)hetero-nanofibers ... SnO_(2)/Co_(3)O_(4)nanofibers(NFs)are synthesized by using a homopolar electrospinning system with double jets of positive polarity electric fields.The morphology and structure of SnO_(2)/Co_(3)O_(4)hetero-nanofibers are characterized by using field emission scanning electron microscope(FE-SEM),transmission electron microscope(TEM),x-ray diffraction(XRD),and x-ray photoelectron spectrometer(XPS).The analyses of SnO_(2)/Co_(3)O_(4)NFs by EDS and HRTEM show that the cobalt and tin exist on one nanofiber,which is related to the homopolar electrospinning and the crystallization during sintering.As a typical n-type semiconductor,Sn O_(2)has the disadvantages of high optimal operating temperature and poor reproducibility.Comparing with Sn O_(2),the optimal operating temperature of SnO_(2)/Co_(3)O_(4)NFs is reduced from 350℃to 250℃,which may be related to the catalysis of Co_(2)O_(2).The response of SnO_(2)/Co_(3)O_(4)to 100-ppm ethanol at 250℃is 50.9,9 times higher than that of pure Sn O_(2),which may be attributed to the p–n heterojunction between the n-type Sn O_(2)crystalline grain and the p-type Co_(2)O_(2)crystalline grain.The nanoscale p–n heterojunction promotes the electron migration and forms an interface barrier.The synergy effects between Sn O_(2)and Co_(2)O_(2),the crystalline grain p–n heterojunction,the existence of nanofibers and the large specific surface area all jointly contribute to the improved gas sensing performance. 展开更多
关键词 SnO_(2)/Co_(3)O_(4)nanofibers(nfs) homopolar double jets electrospinning gas sensors nanoscale p-n heterojunction
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A Functional Scoring System to Assess the Level of Impairment in Patients with Low Vision Impairment 被引量:1
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作者 Geeta Shroff 《Open Journal of Ophthalmology》 2017年第3期204-215,共12页
Background: Low vision is referred to as visual impairment (VI) if it is not cured through surgery, drugs, spectacles or contact lenses. It interferes with day-to-day living activities and is associated with the major... Background: Low vision is referred to as visual impairment (VI) if it is not cured through surgery, drugs, spectacles or contact lenses. It interferes with day-to-day living activities and is associated with the major eye blinding diseases. Numerous tests are used to carry out diagnosis of VI, but their outcomes are unreliable. Objective: To develop a functional scoring system, for accessing the ailment of patients with VI based on observations and clinical symptoms. Methods and Findings: We prepared the list of all possible symptoms that were associated with low vision. Based on this list, we established a scoring system, Nutech Functional Score (NFS), which is a 33-point positional and directional scoring system that evaluates the patient with VI. The scores have been converted into numeric values for conducting probability based studies. All the symptoms are graded between 1 to 5 that runs in BAD → GOOD direction. Conclusion: NFS is a distinctive tool that can be used globally to evaluate the patients with low vision. 展开更多
关键词 Nutech FUNCTIONAL Score (nfs) VISUAL IMPAIRMENT Cortical VISUAL IMPAIRMENT (CVI) Positional SCORING System Ocular VISUAL IMPAIRMENT (OVI)
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Intensification of Power Quality Using PMSG and Cascaded Multi Cell Trans-Z-Source Inverter 被引量:1
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作者 E. Rajendran Dr. C. Kumar Dr. P. Suresh 《Circuits and Systems》 2016年第11期3778-3793,共17页
This script depicts the power quality intensification of Wind Energy Transfer System (WETS) using Permanent Magnet Synchronous Generator (PMSG) and Cascaded Multi Cell Trans-Z-Source Inverter (CMCTZSI). The PMSG knock... This script depicts the power quality intensification of Wind Energy Transfer System (WETS) using Permanent Magnet Synchronous Generator (PMSG) and Cascaded Multi Cell Trans-Z-Source Inverter (CMCTZSI). The PMSG knocks the induction generator and earlier generators, because of their stimulating performances without taking the frame power. The Trans-Z-Source Inverter with one transformer and one capacitor is connected newly. To increase the boosting ratio gratuity a cascaded impression is proposed with adopting multi-winding transformer which provides an option for this manuscript to use coupled inductor as an alternative of multi-winding transformer and remains the matching voltage gain as cascaded multi cell trans-Z- source inverter. Accordingly the parallel capacitances are also balancing the voltage gain. The parallel correlation of the method is essentially to trim down the voltage stresses and to improve the input current gain of the inverter. By using MALAB Simulation, harmonics can be reduced up to 1.32% and also DC side can be boosted up our required level 200 - 1000 V achievable. The new hardware setup results demonstrate to facilitate the multi cell Trans Z-source inverter. This can be generated high-voltage gain [50 V - 1000 V] and also be credible. Moreover, the level of currents, voltages and Harmonics on the machinery is low. 展开更多
关键词 Neuro Fuzzy System (nfs) Permanent Magnet Synchronous Generator (PMSG) Cascaded Multi Cell Trans-Z-Source Inverter (CMCTZSI) Wind Energy Transfer System (WETS)
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A Scoring System to Assess Patients with Diabetes: Nutech Functional Score
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作者 Geeta Shroff 《Journal of Diabetes Mellitus》 2015年第4期245-251,共7页
Background: Diabetes mellitus (DM) is a metabolic disorder characterized by hyperglycemia. The symptoms of hyperglycemia include polyuria, polydypsia, polyphagia, blurred vision and weight loss. Various diagnostic tes... Background: Diabetes mellitus (DM) is a metabolic disorder characterized by hyperglycemia. The symptoms of hyperglycemia include polyuria, polydypsia, polyphagia, blurred vision and weight loss. Various diagnostic tests are used for the diagnosis of DM in patients, but the findings of these tests cannot be assumed to be completely valid. This study aimed at developing a novel scoring system to assess the patients suffering from DM. Method: We assessed the patients based on various diagnostic tests available for DM and prepared a single list of these tests. The tests were categorized and graded based on the World Health Organization (WHO) criteria. Further, we coverted the grades into numeric values for easy use. Results: NFS for diabetes is an 11-point scoring system that assesses the patient’s condition before and after therapy. To facilitate the conduct of probability based studies, we have converted the scores into numeric values in the range of (0, 1). Each symptom is graded as (1, 2, 3, 4, 5) that runs in BAD → GOOD direction. Conclusion: NFS is a beneficial scoring system that can be used worldwide to assess the patients with DM. 展开更多
关键词 DIABETES MELLITUS Nutech FUNCTIONAL SCORE (nfs) SCORING System Diagnosis
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Advancing sustainable agriculture: Enhancing crop nutrition with next-generation nanotech-based fertilizers
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作者 Yiwen Liao Dawei Xu +1 位作者 Yuhong Cao Yong-Guan Zhu 《Nano Research》 SCIE EI CSCD 2023年第12期13205-13225,共21页
The pressing need to enhance nutrient use efficiency(NUE)in fertilizers has become increasingly urgent in light of food insecurity and climate-related issues.Nanotechnology offers promising prospects for the developme... The pressing need to enhance nutrient use efficiency(NUE)in fertilizers has become increasingly urgent in light of food insecurity and climate-related issues.Nanotechnology offers promising prospects for the development of effective and environmentally friendly alternatives in the field of fertilization.This review focuses on the impact of nanotechnology on conventional fertilizers,encompassing inorganic,organic,and microbial approaches.We emphasize the superior attributes of nano-fertilizers compared with their conventional counterparts and explore their potential and versatility in boosting crop productivity,reducing fertilizer expenses,and mitigating detrimental environmental impacts.In conclusion,given the significant challenges posed by food insecurity and climate change,the application of nano-fertilizers demonstrates immense potential for advancing sustainable and intelligent agricultural practices. 展开更多
关键词 NANOBIOTECHNOLOGY nano-fertilizers(nfs) nutrient use efficiency(NUE) slow release sustainable agriculture
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Some Statistical Properties of Feedforward Sequences (Ⅱ)
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作者 戴宗铎 冯绪宁 +1 位作者 刘木兰 万哲先 《Science China Mathematics》 SCIE 1994年第2期129-136,共8页
In this paper,we continuously discuss the statistical properties of non-linear feedforward sequences of m-sequences We give the number of 0-runs and 1-runs in some cases.
关键词 NON-LINEAR FEEDFORWARD SEQUENCES (nfs) FIBONACCI sequence 0-runs and 1-runs
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Assembly and structure of neurofilaments isolated from bovine spinal cord
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作者 佟向军 陈建国 +2 位作者 刘洁 庞世瑾 翟中和 《Science China(Life Sciences)》 SCIE CAS 1999年第3期233-239,共7页
Neurofilaments (NFs) are neuron-specific intermediate filaments. The NFs were isolated from bovine spinal cord by differential centrifugation. The NFs were detected with electron microscopy and scanning tunneling micr... Neurofilaments (NFs) are neuron-specific intermediate filaments. The NFs were isolated from bovine spinal cord by differential centrifugation. The NFs were detected with electron microscopy and scanning tunneling microscopy (STM). Under STM, two kinds of sidearm of NFs were revealed: one was short, the other was long. They were arrayed along the 10-nm width core filaments one by one. The intervals between two adjacent long sidearms or two short sidearms were 20—22 nm, while those between two adjacent long and short sidearms were 10—11 nm. It was proposed that the rod domain of NF triplet prnteins was 3/4-staggered. The assembly properties of NF triplet proteins were also studied. Immuno-colloidal-gold labeling assay showed that NF-M and NF-H are able to co-assemble into long filaments with NF-L. NF-M and NF-H can also co-constitute into winding filaments. 展开更多
关键词 NEUROFILAMENTS (nfs) STM sidearm STRUCTURE ASSEMBLY immunogold.
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Application of metal oxides-based nanofluids in PV/T systems: a review
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作者 Shahriar Ahmed KH.Nazmul Ahshan +1 位作者 MdNur Alam Mondal Shorab Hossain 《Frontiers in Energy》 SCIE CSCD 2022年第3期397-428,共32页
Having the wide application of metal oxides in energy technologies, in recent years, many researchers tried to increase the performance of the PV/T system by using metal oxide-based nanofluids (NFs) as coolants or opt... Having the wide application of metal oxides in energy technologies, in recent years, many researchers tried to increase the performance of the PV/T system by using metal oxide-based nanofluids (NFs) as coolants or optical filters or both at the same time. This paper summarizes recent research activities on various metal oxides (Al2O3, TiO2, SiO2, Fe3O4, CuO, ZnO, MgO)-based NFs performance in the PV/T system regarding different significant parameters, e.g., thermal conductivity, volume fraction, mass flowrate, electrical, thermal and overall efficiency, etc. By conducting a comparative study among the metal oxide-based NFs, Al2O3/SiO2-water NFs are mostly used to achieve maximum performance. The Al2O3-water NF has a prominent heat transfer feature with a maximum electrical efficiency of 17%, and a maximum temperature reduction of PV module of up to 36.9°C can be achieved by using the Al2O3-water NF as a coolant. Additionally, studies suggest that the PV cell’s efficiency of up to 30% can be enhanced by using a solar tracking system. Besides, TiO2-water NFs have been proved to have the highest thermal efficiency of 86% in the PV/T system, but TiO2 nanoparticles could be hazardous for human health. As a spectral filter, SiO2-water NF at a size of 5 nm and a volume fraction of 2% seems to be very favorable for PV/T systems. Studies show that the combined use of NFs as coolants and spectral filters in the PV/T system could provide a higher overall efficiency at a cheaper rate. Finally, the opportunities and challenges of using NFs in PV/T systems are also discussed. 展开更多
关键词 metal oxide nanofluids(nfs) nanoparticles(NPs) optical filter PV/T systems solar energy
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A Note on the Behaviour of the Number Field Sieve in the Medium Prime Case: Smoothness of Norms
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作者 BENGER Naomi CHARLEMAGNE Manuel 陈克非 《Journal of Shanghai Jiaotong university(Science)》 EI 2018年第1期138-145,共8页
As we examine the behaviour of the number field sieve(NFS) in the medium prime case, we notice various patterns that can be exploited to improve the running time of the sieving stage. The contributions of these observ... As we examine the behaviour of the number field sieve(NFS) in the medium prime case, we notice various patterns that can be exploited to improve the running time of the sieving stage. The contributions of these observations to the computational mathematics community are twofold. Firstly, we clarify the understanding of the true practical effectiveness of the algorithm. Secondly, we propose a test for a better choice of the polynomials used in the NFS. These results are of particular interest to cryptographers as the run-time of the NFS directly determines the security level of some discrete logarithm problem based protocols. 展开更多
关键词 number field sieve(nfs) pairing friendly elliptic curves polynomial selection
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