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Availability growth models and verification of power equipment

Jinyuan SHI, Jiamin XU

《能源前沿（英文）》 2021年第15卷第2期页码 529-538 doi: 10.1007/s11708-019-0624-0

摘要： The general availability growth models for large scale complicated repairable system such as electric generating units, power station auxiliaries, and transmission and distribution installations are presented. The calculation formulas for the maintenance coefficient, mathematical expressions for general availability growth models, ways for estimating, and fitting on checking the parameters of the model are introduced. Availability growth models for electric generating units, power station auxiliaries, and transmission and distribution installations are given together with verification examples for availability growth models of 320–1000 MW nuclear power units and 1000 MW thermal power units, 200–1000 MW power station auxiliaries, and 220–500 kV transmission and distribution installations. The verification results for operation availability data show that the maintenance coefficients for electric generating units, power station auxiliaries, transmission and distribution installations conform to the power function, and general availability growth models conform to rules of availability growth tendency of power equipment.

关键词： repairable system power equipment electric generating unit power station auxiliary transmission and distribution installation reliability availability availability growth model

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Bridging reliability and operations management for superior system availability: Challenges and opportunities

《工程管理前沿（英文）》页码 391-405 doi: 10.1007/s42524-022-0206-4

摘要： Recently, firms have begun to handle the design, manufacturing, and maintenance of capital goods through a consolidated mechanism called the integrated product-service system. This new paradigm enables firms to deliver high-reliability products while lowering the ownership cost. Hence, holistic optimization models must be proposed for jointly allocating reliability, maintenance, and spare parts inventory across the entire value chain. In the existing literature, these decisions are often made fragmentally, thus resulting in local optimality. This study reviews the extant works pertaining to reliability-redundancy allocation, preventative maintenance, and spare parts logistics models. We discuss the challenges and opportunities of consolidating these decisions under an integrated reliability-maintenance-inventory framework for attaining superior system availability. Specific interest is focused on the new product introduction phase in which firms face a variety of uncertainties, including installed base, usage, reliability, and trade policy. The goal is to call for tackling the integrated reliability-maintenance-inventory allocation model under a nonstationary operating condition. Finally, we place the integrated allocation model in the semiconductor equipment industry and show how the firm deploys reliability initiatives and after-sale support logistics to ensure the fleet uptime for its global customers.

关键词： system availability product-service integration installed base new product introduction service supply chain reliability-maintenance-inventory optimization

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Analyzing the service availability of mobile cloud computing systems by fluid-flow approximation

Hong-wu LV,Jun-yu LIN,Hui-qiang WANG,Guang-sheng FENG,Mo ZHOU

《信息与电子工程前沿（英文）》 2015年第16卷第7期页码 553-567 doi: 10.1631/FITEE.1400410

摘要： Mobile cloud computing (MCC) has become a promising technique to deal with computation- or data-intensive tasks. It overcomes the limited processing power, poor storage capacity, and short battery life of mobile devices. Providing continuous and on-demand services, MCC argues that the service must be available for users at anytime and anywhere. However, at present, the service availability of MCC is usually measured by some certain metrics of a real-world system, and the results do not have broad representation since different systems have different load levels, different deployments, and many other random factors. Meanwhile, for large-scale and complex types of services in MCC systems, simulation-based methods (such as Monte-Carlo simulation) may be costly and the traditional state-based methods always suffer from the problem of state-space explosion. In this paper, to overcome these shortcomings, fluid-flow approximation, a breakthrough to avoid state-space explosion, is adopted to analyze the service availability of MCC. Four critical metrics, including response time of service, minimum sensing time of devices, minimum number of nodes chosen, and action throughput, are defined to estimate the availability by solving a group of ordinary differential equations even before the MCC system is fully deployed. Experimental results show that our method costs less time in analyzing the service availability of MCC than the Markov- or simulation-based methods.

关键词： Service availability Mobile cloud computing Fluid-flow approximation Ordinary differential equations

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Aerobic granular sludge formation based on substrate availability: Effects of flow pattern and fermentation

Quan Yuan, Hui Gong, Hao Xi, Kaijun Wang

《环境科学与工程前沿（英文）》 2020年第14卷第3期 doi: 10.1007/s11783-020-1226-0

摘要： Penetration depth and substrate characters affect AGS formation and performance. The relationship between substrate gradient and particle size affects AGS stability. The fermentation process is proposed as a pretreatment to improve AGS stability. The influences of flow patterns (mixed-flow and plug-flow) and fermentation pretreatment on aerobic granular sludge (AGS) formation with various substrate availability levels were investigated by running four identical laboratory-scale sequencing batch reactors (R1–R4), comparing two anaerobic feeding strategies and three kinds of substrates. R1 achieved faster granulation with a fast influent fill step followed by a modified anaerobic mixed-flow phase, but the AGS showed poorer stability with a cracked structure and a high suspended solids concentration in the effluent. The anaerobic plug-flow feeding mode (with influent fed slowly from the bottom) in R2 provided deeper penetration depth for the substance to reach the core of AGS and accordingly strengthen AGS stability. An acidogenic up-flow sludge bed reactor was introduced as a pretreatment to improve the AGS performance by enhancing glucose pre-fermentation (R4). AGS fed with mixed volatile fatty acids (VFA) after glucose fermentation showed similar performance compared with the reactor fed with acetate in the aspects of stability, structure, size distribution and nitrogen removal efficiency, and 74% similarity in the microbial community. For actual wastewater with low VFA concentrations, fermentation treatment was suggested as a promising pretreatment for stable AGS granulation and operation.

关键词： Anaerobic plug-flow feeding mode Anaerobic mixed-flow mode Fermentation pretreatment Substrate gradient Penetration depth

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Reliability prediction and its validation for nuclear power units in service

Jinyuan SHI,Yong WANG

《能源前沿（英文）》 2016年第10卷第4期页码 479-488 doi: 10.1007/s11708-016-0425-7

摘要： In this paper a novel method for reliability prediction and validation of nuclear power units in service is proposed. The equivalent availability factor is used to measure the reliability, and the equivalent availability factor deducting planed outage hours from period hours and maintenance factor are used for the measurement of inherent reliability. By statistical analysis of historical reliability data, the statistical maintenance factor and the undetermined parameter in its numerical model can be determined. The numerical model based on the maintenance factor predicts the equivalent availability factor deducting planed outage hours from period hours, and the planed outage factor can be obtained by using the planned maintenance days. Using these factors, the equivalent availability factor of nuclear power units in the following 3 years can be obtained. Besides, the equivalent availability factor can be predicted by using the historical statistics of planed outage factor and the predicted equivalent availability factor deducting planed outage hours from period hours. The accuracy of the reliability prediction can be evaluated according to the comparison between the predicted and statistical equivalent availability factors. Furthermore, the reliability prediction method is validated using the nuclear power units in North American Electric Reliability Council (NERC) and China. It is found that the relative errors of the predicted equivalent availability factors for nuclear power units of NERC and China are in the range of –2.16% to 5.23% and –2.15% to 3.71%, respectively. The method proposed can effectively predict the reliability index in the following 3 years, thus providing effective reliability management and maintenance optimization methods for nuclear power units.

关键词： nuclear power units in service reliability reliability prediction equivalent availability factors

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具有容错结构的高可用计算机双系统研究

金士尧,胡华平,李宏亮

《中国工程科学》 1999年第1卷第3期页码 46-50

摘要：

为了确保高的可用性，在重大工程实践中往往采用具有容错结构的计算机双系统。双系统处理得到两个结果的异同性，历来是研究双系统容错的技术重点和难点。文章在双系统可用性分析、结果判错与选择、以及双工切换技术方面都有突破性的进展，并在重点工程中得以实现，取得显著效果。

关键词：可用性双工系统故障判别率切入成功率

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A reliability growth model for 300?MW pumped-storage power units

Jinyuan SHI , Yu YANG , Zhicheng DENG ,

《能源前沿（英文）》 2009年第3卷第3期页码 337-340 doi: 10.1007/s11708-009-0032-y

摘要： A reliability growth model for pumped-storage power units is presented. Ways for estimating and fitting on checking the model’s parameters are given together with analysis results concerning the reliability growth of 300MW pumped-storage power units. On site operation, reliability data show that the reliability growth model conforms to rules of reliability growth tendency. Analysis results of reliability growth indicate that measures taken for improving maintenance and operation by the pumped-storage power companies are effective and that the reliability of the 300MW pumped-storage power units exhibits a rising tendency.

关键词： pump-storage power unit availability reliability growth reliability prediction

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大数据存储技术综述 Review

Aisha SIDDIQA, Ahmad KARIM, Abdullah GANI

《信息与电子工程前沿（英文）》 2017年第18卷第8期页码 1040-1070 doi: 10.1631/FITEE.1500441

摘要：对于容量快速增长、日趋多元化的大数据，业界亟需开发可行性更好的存储工具。为满足大数据存储需求，存储机制已经形成从传统数据管理系统到NoSQL技术的结构化转移。然而，目前可用的大数据存储技术无法为持续增长的异构数据提供一致、可扩展和可用的解决方案。在科学实验、医疗保健、社交网络和电子商务等实际应用中，存储是大数据分析的第一步。截至目前，亚马逊、谷歌和阿帕奇等公司形成了大数据存储方案的行业标准，但尚未有关于大数据存储技术性能和容量提升的深入调查和文献报告。本文旨在对目前可用于大数据的最先进的存储技术进行全面调查，提供了一个明确的大数据存储技术分类方法，以帮助数据分析师和研究人员了解和选择更适合其需求的存储机制。我们使用布鲁尔的CAP定理比较和分析了现有存储方法，评估了不同存储架构的性能，讨论了存储技术的意义、应用及其对其他类别数据的支持。为了加快部署可靠和可扩展的存储系统，文中还突出了未来研究面临的几个挑战。

关键词：大数据；大数据存储；NoSQL数据库；分布式数据库；CAP定理；可扩展性；一致性-分区弹性；可用性-分区弹性

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Optimal generation scheduling in power system using frequency prediction through ANN under ABT environment

Simarjit KAUR, Yajvender Pal VERMA, Sunil AGRAWAL

《能源前沿（英文）》 2013年第7卷第4期页码 468-478 doi: 10.1007/s11708-013-0282-6

摘要： In a competitive and deregulated power scenario, the utilities try to maintain their real electric power generation in balance with the load demand, which creates a need for the precise real time generation scheduling (GS). In this paper, the GS problem is solved to perform the unit commitment (UC) based on frequency prediction by using artificial neural network (ANN) with the objective to minimize the overall system cost of the state utility. The introduction of availability-based tariff (ABT) signifies the importance of frequency in GS. Under-prediction or over-prediction will result in an unnecessary commitment of generating units or buying power from central generating units at a higher cost. Therefore, an accurate frequency prediction is the first step toward optimal GS. The dependency of frequency on various parameters such as actual generation, load demand, wind power and power deficit has been considered in this paper. The proposed technique provides a reliable solution for the input parameter different from the one presented in the training data. The performance of the frequency predictor model has been evaluated based on the absolute percentage error (APE) and the mean absolute percentage error (MAPE). The proposed predicted frequency sensitive GS model is applied to the system of Indian state of Tamilnadu, which reduces the overall system cost of the state utility by keeping off the dearer units selected based on the predicted frequency.

关键词： artificial neural network (ANN) frequency prediction availability-based tariff (ABT) generation scheduling (GS)

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Availability of wind energy resource potential for power generation at Jos, Nigeria

O. O. Ajayi, R. O. Fagbenle, J. Katende, J. O. Okeniyi

《能源前沿（英文）》 2011年第5卷第4期页码 376-385 doi: 10.1007/s11708-011-0167-5

摘要： The objective of this study was to assess the potential viability of the wind resource potential in Jos, Plateau state, Nigeria for power generation. The monthly mean wind speeds that span from 1987 to 2007 were employed to statistically analyze the monthly, annual and seasonal potentials of the wind energy resources at the site. Besides, the results were employed together with two models of wind energy conversion system to simulate the likely average output power. The outcome showed that Jos was suitable as a site for wind farm projects of varying sizes and that MW·h to GW·h of electricity is likely to be produced per period of months, seasons and years. The average wind speed range at the site was also estimated to be between 6.7 and 11.8 m/s across the months, years and seasons.

关键词： green electricity renewable resources Weibull statistics Jos Nigeria

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高性能计算机的关键技术和发展趋势

金怡濂,黄永勤,陈左宁,桂亚东,漆锋滨

《中国工程科学》 2001年第3卷第6期页码 1-8

摘要：

介绍高性能计算机的关键技术和发展趋势。简要回顾高性能计算机的发展历史和当前形势，重点讨论大规模并行处理（MPP）所面临的挑战，包括可扩展性、友善性和可用性。介绍神威高性能计算机及其应用情况，并对如何发展我国高性能计算机提出一些初浅的看法。

关键词：大规模并行处理系统软件并行编译系统效率可扩展性可用性

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Anefficient data layout scheme for better I/O balancing inRAID-6 storage systems

Ping XIE,Jian-zhong HUANG,Er-wei DAI,Qiang CAO,Chang-sheng XIE

《信息与电子工程前沿（英文）》 2015年第16卷第5期页码 335-345 doi: 10.1631/FITEE.1400362

摘要： 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 by 29.9% compared to the PC scheme.

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

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饲料的分子结构与动物营养物质利用率和有效性的关系——一种新方法

俞培强, Luciana L. Prates

《工程（英文）》 2017年第3卷第5期页码 726-730 doi: 10.1016/J.ENG.2017.03.007

摘要：

新的研究思路、研究方法和生物分析技术的创造和发展对动物科学（包括饲料和营养科学）的进步是必不可少的。本文介绍了以同步加速器为基础的先进生物分析技术作为一项崭新的研究工具，在研究由多种处理（如基因修饰、基因沉默、饲料的热加工处理、生物燃料加工等）诱导的饲料分子结构变化与动物消化吸收饲料营养物质的关系方面的潜在应用。以同步辐射为基础的先进技术[如同步辐射红外显微光谱技术（synchrotron radiation infrared microspectroscopy，SR-IMS）和同步辐射X射线技术]作为一种快速、无损的生物分析技术被开发利用。与传统的湿化学法不同，同步辐射技术不会破坏饲料内在的分子结构。尖端和先进的同步加速器光源（是日光的上百万倍）能够以超高分辨率在细胞和分子水平上探测生物组织的内在结构。总的来说，最近开发的基于同步辐射的生物分析技术结合常用的研究技术将带来动物饲料和营养研究的巨大进步。

关键词：内部分子结构同步辐射应用分子营养饲料科学技术分子成像养分消化与吸收

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中国车用能源需求和关键材料资源可获性分析

彭天铎,袁志逸,袁杰辉,朱旭峰,欧训民

《中国工程科学》 2018年第20卷第1期页码 127-132 doi: 10.15302/J-SSCAE-2018.01.018

摘要：

随着中国汽车产销量和保有量的迅速增长，车用能源和资源成为汽车强国战略中的一个重要问题。本研究基于清华大学中国车用能源研究中心所开发的中国汽车保有量预测模型，对未来汽车规模进行预测，对车用能源和资源的利用现状、技术发展水平、发展趋势等进行研究，并提出相应政策建议。研究结果表明，中国汽车保有量将持续增长，车用燃料供需矛盾将进一步凸显，汽车材料所需矿产资源储备、产品性能和技术水平有待提升。建议出台相关政策，提前布局，积极应对未来汽车工业面临的能源和资源方面的挑战。

关键词：汽车保有量车用能源矿产资源发展对策

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SA-RSR：一种适用于异或类纠删码分布式存储系统的数据读取最优恢复方法 Research Articles

张兴军1,梁宁静1,刘云飞1,张长江1,李洋2

《信息与电子工程前沿（英文）》 2022年第23卷第6期页码 858-875 doi: 10.1631/FITEE.2100242

摘要：

冗余策略经常被用于分布式存储系统，以保证数据的可靠性与可用性。纠删码是一种代表性的冗余策略，具有低存储开销优势，这种优势促进了它在分布式存储系统中的应用。在各种纠删码机制中，异或类纠删码凭借高计算效率变得越来越流行。采用异或类纠删码机制的存储系统，如果发生单节点故障，便会进行数据恢复，该过程需要从幸存节点中下载数据，然后恢复故障节点中的数据。然而，数据恢复过程中的数据传输通常需要相当长时间。目前研究主要集中在通过减少数据恢复过程所需数据量，减少数据传输所需时间，但存在复杂度高和局部最优解等问题。本文提出一种随机搜索恢复算法，SA-RSR，该算法能加速异或类纠删码单节点故障恢复。SA-RSR利用模拟退火技术寻找读取和传输最少数据量的最优恢复机制，且该搜索过程可在多项式时间内完成。最后，为验证该方法的有效性，使用多种异或类纠删码进行仿真验证，并在真实存储系统Ceph中验证。实验结果表明，与传统恢复方法相比，SA-RSR减少了30%的数据读取与传输量，提高了20.36%的数据恢复性能。

关键词：分布式存储系统；数据可靠性与可用性；异或类纠删码；单节点失效；数据恢复

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标题作者时间类型操作

Availability growth models and verification of power equipment

Jinyuan SHI, Jiamin XU

期刊论文

Bridging reliability and operations management for superior system availability: Challenges and opportunities

期刊论文

Analyzing the service availability of mobile cloud computing systems by fluid-flow approximation

Hong-wu LV,Jun-yu LIN,Hui-qiang WANG,Guang-sheng FENG,Mo ZHOU

期刊论文

Aerobic granular sludge formation based on substrate availability: Effects of flow pattern and fermentation