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Joint optimization of LORA and spares stocks considering corrective maintenance time 被引量:10
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作者 Linhan Guo Jiujiu Fan +1 位作者 Meilin Wen Rui Kang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2015年第1期85-95,共11页
Level of repair analysis(LORA) is an important method of maintenance decision for establishing systems of operation and maintenance in the equipment development period. Currently, the research on equipment of repair... Level of repair analysis(LORA) is an important method of maintenance decision for establishing systems of operation and maintenance in the equipment development period. Currently, the research on equipment of repair level focuses on economic analysis models which are used to optimize costs and rarely considers the maintenance time required by the implementation of the maintenance program. In fact, as to the system requiring high mission complete success, the maintenance time is an important factor which has a great influence on the availability of equipment systems. Considering the relationship between the maintenance time and the spares stocks level, it is obvious that there are contradictions between the maintenance time and the cost. In order to balance these two factors, it is necessary to build an optimization LORA model. To this end, the maintenance time representing performance characteristic is introduced, and on the basis of spares stocks which is traditionally regarded as a decision variable, a decision variable of repair level is added, and a multi-echelon multiindenture(MEMI) optimization LORA model is built which takes the best cost-effectiveness ratio as the criterion, the expected number of backorder(EBO) as the objective function and the cost as the constraint. Besides, the paper designs a convex programming algorithm of multi-variable for the optimization model, provides solutions to the non-convex objective function and methods for improving the efficiency of the algorithm. The method provided in this paper is proved to be credible and effective according to the numerical example and the simulation result. 展开更多
关键词 level of repair spares convex optimization multi-echelon multi-indenture(MEMI)
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Mission-oriented dynamic optimization model of carrying spares for warship redundant system 被引量:5
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作者 RUAN Minzhi LI Hua WANG Junlong 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第3期539-548,共10页
Redundancy is a common structure for warship system,and it is an effective way to improve the reliability of the system.In this paper, warship system is taken as the object of study,based on the system reliability equ... Redundancy is a common structure for warship system,and it is an effective way to improve the reliability of the system.In this paper, warship system is taken as the object of study,based on the system reliability equivalence principle, a spares demand rate calculation method for redundant system is proposed through structure transformation. According to the system analysis method, the general modeling data structure of spares support echelon and system indenture is established, and the mission success probability is taken as the optimization target to build the dynamic optimization model of carrying spares during the process of multi-phase. By introducing the Lagrange multiplier, the spares weight, volume and cost are transformed to the single target of the spares total scale, and the initial Lagrange factors and its dynamic adjustment policy is proposed. In a given example, the main influence factors of the carrying spares project are analyzed, and the study results are in accordance with the reality, which can provide a new approach to mission-oriented carrying spares optimization for the redundant system. 展开更多
关键词 REDUNDANCY reliability equivalence WARSHIP carrying spares OPTIMIZATION
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Mission-Oriented Configuration Model of Aircraft Carrying Spares and Dynamic Optimization Policy 被引量:3
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作者 Ruan Minzhi Wang Rui Kong Qingfu 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2016年第5期626-632,共7页
Spare parts are critical to scheduled maintenance and fault repair, and can directly affect the readiness and combat capability of equipment. Equipmentrs capacity of carrying spares is influenced by its storage space ... Spare parts are critical to scheduled maintenance and fault repair, and can directly affect the readiness and combat capability of equipment. Equipmentrs capacity of carrying spares is influenced by its storage space and scales, so it is necessary to consider economic factors, e.g. spares cost, as well as non-economic ones, such as spares volume, mass and scale, when optimizing spares configuration. Aiming at this problem, the optimization model based on multi-constraints for carrying spares is built by METRIC theory and system analysis. Through the introduction of Lagrange factors, the spares cost is transformed to shadow price, and the optimization method for carrying spares and the dynamic adjustment policy of Lagrange factors are proposed. The result of a given example is analyzed, and demonstrates that the proposed model can be optimized with all constraints, and the research can provide a new way for carrying spares optimization. 展开更多
关键词 carrying spares projectl multi-constrains optimization Lagrange factors operational availability
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An Optimal Replacement Policy for a System with Finite Spares 被引量:1
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作者 Zhao Jianmin(Shijiazhuang Mechanical Engineering College, 050003, P. R. China )Zhao JianhuaShijiazhuang Education College, 050000, P. R. China 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 1999年第3期76-81,共6页
This paper develops a new replacement policy for a system with multiple spare units.An optimal replacement period is determined by maximizing the mean time to failure of the system.We show that there exists a finite a... This paper develops a new replacement policy for a system with multiple spare units.An optimal replacement period is determined by maximizing the mean time to failure of the system.We show that there exists a finite and unique optimal replacement period T for units with strictly increasing failure rates. We also proof that the optimal repIacement period for a system with spares is decreasing in k. Furthermore, an algorithm is presented to get the optimal replacement period and a numerical example is given to illustrate the result. with strictly 展开更多
关键词 REPLACEMENT OPTIMIZATION spare
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Study to Cost of Air Spares Support Based on IPSO 被引量:1
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作者 Xiaohua Wang Aiqin Mu +1 位作者 Fuhong Wang Zhongbing Tang 《Journal of Transportation Technologies》 2012年第1期75-77,共3页
Air spares support is general term of using and repairing of aircrafts which is the material foundation of aero technical support, its effectiveness influences operational effectiveness and equipments of aircrafts dir... Air spares support is general term of using and repairing of aircrafts which is the material foundation of aero technical support, its effectiveness influences operational effectiveness and equipments of aircrafts directly. Based on particle swarm optimization algorithm, a new model is proposed to optimize the distribution of the cost of air spares, it take the funds as resource and the improvement of performance efficiency as objective and deduces the expressions to get the best distribution plan. The results of experiments indicate that this model can make full use of the limited funds and obtain the highest efficiency of air spares support. 展开更多
关键词 AIR spares SUPPORT FUND PARTICLE SWARM Optimization
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New Approach to Calculate the Unavailability of Identical Spares in Cold Spare Configuration
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作者 NYAN Win-aung 魏海军 柳霆 《Journal of Donghua University(English Edition)》 EI CAS 2014年第6期863-869,共7页
Cold spare is the most common configuration amongst the three types of configuration for systems used on board and for power generation systems. A new approach to calculate the unavailability of systems composed of id... Cold spare is the most common configuration amongst the three types of configuration for systems used on board and for power generation systems. A new approach to calculate the unavailability of systems composed of identical spares in cold spare configuration was proposed in this study. Instead of using the spare gate of dynamic fault tree( DFT) and the Markov analysis,AND gate of static fault tree used for calculating the unavailability of cold spare systems was proposed in this paper. By using this approach,unavailability of identical cold spare systems composed of nonrepairable spare components can be calculated exactly and systems composed of both repairable and nonreparable identical spare components can be estimated without building large Markov state diagram. 展开更多
关键词 cold spare spare gate AND gate failure percentage(FP) fault tree analysis Markov analysis
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Confidence Level of System Spares OptimizationUsing Fuzzy Theory
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作者 Liu Xiaodong Zhang Hengxi(Airforce University of Engineering, Xi’an 710038, RR.China) 《International Journal of Plant Engineering and Management》 2000年第1期12-16,共5页
To obtain a higher readiness for a complex system, the common method is to store some spares. Confidence level of system spares is an important parameter to control the probability of the spares required. By introduci... To obtain a higher readiness for a complex system, the common method is to store some spares. Confidence level of system spares is an important parameter to control the probability of the spares required. By introducing fuzzy theory, this paper allocates the confidence level of system spares to its subsystems, thus to achieve a rational management of system spares, 展开更多
关键词 spares confidence level fuzzy theory optimization.
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A Bound Heuristic Technique for Solving DRAMA Spares Optimizations
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作者 LI Jian-ping KANG Jian-she(Department of Management Engineering, Shijiazhuang Mechanical Engineering College,Shijiazhuang, Hebei, 050003, China, E-mail:jp.Ji@sjz.col.com.cn) 《International Journal of Plant Engineering and Management》 1999年第2期442-453,共12页
This paper studies the solution technique to solve the DRAMA spares allocation optimization problem. DRAMA model is an analytic spare optimization model of a multi-item, multi-location, and two-echelon inventory syste... This paper studies the solution technique to solve the DRAMA spares allocation optimization problem. DRAMA model is an analytic spare optimization model of a multi-item, multi-location, and two-echelon inventory system. The computation of its system spares availability is much complicated. The objective function and constraint functions of DRAMA model could be written as the separable forms. A new bound heuristic algorithm has been presented by improving the bound heuristic algorithm for solving the reliability redundancy optimization problem (BHA in short). With the results, the proposed algorithm has been found to be more economical and effective than BHA to obtain the solutions of large DRAMA model. The new algorithm could be used to solve reliability redundancy optimization problems with the separable forms. 展开更多
关键词 spares optimization reliability optimization integer programming optimal redundancy bound technique heuristic method
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利用解析法有效快速估计将来GRACE Follow-On地球重力场的精度 被引量:36
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作者 郑伟 许厚泽 +3 位作者 钟敏 员美娟 周旭华 彭碧波 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2010年第4期796-806,共11页
本文首次利用解析法有效快速估计了将来GRACE(Gravity Recovely and Climate Experiment)Follow-On地球重力场的精度.第一,基于功率谱原理分别建立了新的GRACE Follow-On卫星激光干涉星间测量系统星间速度、GPS接收机轨道位置和轨道速... 本文首次利用解析法有效快速估计了将来GRACE(Gravity Recovely and Climate Experiment)Follow-On地球重力场的精度.第一,基于功率谱原理分别建立了新的GRACE Follow-On卫星激光干涉星间测量系统星间速度、GPS接收机轨道位置和轨道速度以及加速度计非保守力误差影响累计大地水准面的单独和联合解析误差模型.第二,利用提出的GRACE卫星关键载荷匹配精度指标和美国喷气推进实验室(JPL)公布的GRACE Level1B实测精度指标的一致性,以及估计的GRACE累计大地水准面精度和德国波兹坦地学研究中心(GFZ)公布的EIGEN-GRACE02S地球重力场模型实测精度的符合性,验证了本文建立的解析误差模型是可靠的.第三,论证了GRACE Follow-On卫星不同关键载荷匹配精度指标和轨道高度对地球重力场精度的影响.在360阶处,利用轨道高度250 km、星间距离50 km、星间速度误差1×10^(-9)m/s、轨道位置误差3×10^(-5)m、轨道速度误差3×10^(-8)m/s和非保守力误差3×10^(-13)m/s^2,基于联合解析误差模型估计累计大地水准面的精度为1.231×10^(-1)m.本文的研究不仅为当前GRACE和将来GRACE Follow-On地球重力场精度的有效快速确定提供了理论基础和计算保证,同时对国际将来GRAIL(Gravity Recovery and Interior Laboratory)月球卫星重力测量计划的成功实施具有重要的参考意义. 展开更多
关键词 GRACE follow-on 解析法 误差模型 卫星跟踪卫星模式 地球重力场
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插值公式、相关系数和采样间隔对GRACE Follow-On星间加速度精度的影响 被引量:16
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作者 郑伟 许厚泽 +1 位作者 钟敏 员美娟 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2012年第3期822-832,共11页
本文基于星间加速度法开展了插值公式、相关系数和采样间隔对GRACE Follow-On星间加速度精度影响的研究.模拟结果表明:1)适当增加数值微分公式的插值点数可有效提高插值精度.基于9点Newton插值公式,星间加速度的插值误差为4.401×10... 本文基于星间加速度法开展了插值公式、相关系数和采样间隔对GRACE Follow-On星间加速度精度影响的研究.模拟结果表明:1)适当增加数值微分公式的插值点数可有效提高插值精度.基于9点Newton插值公式,星间加速度的插值误差为4.401×10-13 m.s-2,分别基于7点、5点和3点插值公式,插值误差增加了1.192倍、6.912倍和274.029倍.2)适当增大相关系数可有效降低星间加速度的误差.基于相关系数0.99,星间加速度方差为3.777×10-24 m2.s-4,分别基于相关系数0.90、0.70、0.50和0.00,方差增加了9.780倍、22.404倍、26.217倍和26.820倍.3)随着采样间隔增大,星间加速度方差逐渐降低,但卫星观测值的空间分辨率也同时降低,因此合理选取采样间隔有利于地球重力场精度的提高.4)基于9点Newton插值公式、相关系数(K波段测量系统星间距离和星间速度0.85、GPS轨道位置和轨道速度0.95、星载加速度计非保守力0.90)和采样间隔10s,利用预处理共轭梯度迭代法,精确和快速反演了120阶GRACE Follow-On地球重力场,在120阶处累计大地水准面精度为4.602×10-4 m. 展开更多
关键词 GRACE follow-on 星间加速度法 插值公式 相关系数 采样间隔 地球重力场
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基于GRACE Follow-On卫星重力梯度法精确反演地球重力场 被引量:8
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作者 郑伟 许厚泽 +1 位作者 钟敏 员美娟 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2014年第5期1415-1423,共9页
由于GRACE Follow-On双星系统等效于基线长为星间距离的一维水平重力梯度仪,因此本文基于GRACE Follow—On卫星重力梯度法开展了精确和快速反演下一代地球重力场的可行性论证研究.研究结果表明:第一,基于GRACE Follow-On卫星重力梯... 由于GRACE Follow-On双星系统等效于基线长为星间距离的一维水平重力梯度仪,因此本文基于GRACE Follow—On卫星重力梯度法开展了精确和快速反演下一代地球重力场的可行性论证研究.研究结果表明:第一,基于GRACE Follow-On卫星重力梯度法(GFO-SGGM),利用卫星轨道参数(轨道高度250km、星间距离50km、轨道倾角89°、轨道离心率0.001)、关键载荷测量精度(星间距离10^-6m、星间速度10^-7m·s^-1、星间加速度10^-10 m·s^-2、轨道位置10^-3m、轨道速度10^-6m·s^-1、非保守力10^-11 m·s^-2)、观测时间30天和采样间隔10s反演了120阶地球重力场,在120阶处累计大地水准面精度为9.331×10^-4m.第二,在120阶内,利用将来GRACE Follow—On双星反演地球重力场精度较现有GRACE双星平均提高61倍,因此GRACE Follow-On卫星重力梯度法是进一步提高地球重力场反演精度的优选方法.第三,下一代GRACE Follow—On计划较当前GRACE计划的优点如下:轨道高度更低(200-300km)、载荷精度更高(10^-7~10^-9m·s^-1)和星间距离更短(50--100km). 展开更多
关键词 GRACE follow-on 卫星重力梯度法 一维水平梯度仪 卫星重力反演 地球重力场
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基于残余星间速度法精确和快速反演下一代GRACE Follow-On地球重力场 被引量:6
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作者 郑伟 许厚泽 +2 位作者 钟敏 刘成恕 员美娟 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2014年第1期31-41,共11页
基于新型残余星间速度法(RIRM)反演了120阶GRACE Follow-On地球重力场.第一,由于GPS定轨精度相对较低,通过将激光干涉测距仪的高精度残余星间速度(测量精度10-7 m·s-1)引入残余轨道速度差分矢量的视线分量构建了新型RIRM观测方程.... 基于新型残余星间速度法(RIRM)反演了120阶GRACE Follow-On地球重力场.第一,由于GPS定轨精度相对较低,通过将激光干涉测距仪的高精度残余星间速度(测量精度10-7 m·s-1)引入残余轨道速度差分矢量的视线分量构建了新型RIRM观测方程.第二,基于2点、4点、6点和8点RIRM公式对比论证了最优的插值点数.如果相关系数和采样间隔一定,随着插值点数的增加,卫星观测值的信号量被有效加强,而卫星观测值的误差量也同时增加.因此,6点RIRM公式是提高下一代地球重力场精度的较优选择.第三,相关系数对地球重力场精度的影响在不同频段表现为不同特性.随着相关系数的逐渐增大,地球长波重力场精度逐渐降低,而地球中长波重力场精度逐渐升高.第四,基于6点RIRM公式,通过30天观测数据和采样间隔5s,分别利用星间速度和残余星间速度观测值,在120阶次处反演下一代GRACE Follow-On累计大地水准面精度为1.638×10-3 m和1.396×10-3 m.研究结果表明:(1)残余星间速度观测量较星间速度对地球重力场反演精度更敏感;(2)GRACE FollowOn地球重力场精度较GRACE至少高10倍. 展开更多
关键词 GRACE follow-on卫星 残余星间速度法 激光干涉测距仪 下一代卫星重力反演 累计大地水准面精度
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GRACE与GRACE Follow-On重力卫星数据揭示出的黄河流域2002-2020年干旱特征 被引量:4
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作者 瞿伟 晋泽辉 +2 位作者 张勤 高源 张普方 《测绘学报》 EI CSCD 北大核心 2023年第5期714-724,共11页
研究黄河流域干旱时空变化特征,对认知黄河流域水资源演化规律具有重要意义。本文充分利用GRACE(gravity recovery and climate experiment)与GRACE-FO(GRACE Follow-On)重力卫星在大尺度范围下监测水文信息变化中的优势,基于2002年4月... 研究黄河流域干旱时空变化特征,对认知黄河流域水资源演化规律具有重要意义。本文充分利用GRACE(gravity recovery and climate experiment)与GRACE-FO(GRACE Follow-On)重力卫星在大尺度范围下监测水文信息变化中的优势,基于2002年4月至2020年7月GRACE和GRACE-FO RL06 Mascon数据,计算了黄河流域陆地水储量异常(terrestrial water storage anomaly,TWSA)及对应的水储量亏损赤字(water storage deficit index,WSDI),据此分析了黄河流域上游、中下游干旱事件及其严重性、干旱持续时间、平均与最大水储量赤字等干旱特征,并与其他4种常用干旱指数,标准降水蒸散发指数(standardized precipitation evaporation index,SPEI)、自矫正帕尔默干旱指数(self correct-Palmer drought severity index,sc-PDSI)、标准化降水指数(standardized precipitation index,SPI)和标准化径流指数(standardized runoff index,SRI)识别结果进行了对比分析。研究结果表明:在WSDI识别出的黄河流域上游、中下游分别发生的5期干旱事件及其对应的干旱等级中,存在其他传统干旱指数未识别现象;在黄河流域以往干旱事件识别中,WSDI也展现出了较其他4种传统干旱指数显著的识别优势。相比传统干旱指标多仅依赖于稀疏地表水文监测信息,基于重力卫星监测数据的WSDI干旱指标可在大尺度范围下有效识别出流域干旱特征。 展开更多
关键词 重力卫星 GRACE GRACE follow-on 黄河流域 陆地水储量异常 水储量亏损赤字 干旱指数
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Muscle spare开胸术在胸部手术中特殊情况下的应用
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作者 丁学兵 龚永生 +4 位作者 刘迎梅 汪发九 成刚 张志炜 刘鑫根 《航空航天医学杂志》 2012年第12期1473-1474,共2页
目的:探讨Muscle spare切口在胸部手术中特殊情况下的应用。方法:对2011-01~2011-12收治必须或最适宜进行muscle spare开胸术患者的临床资料进行回顾总结。结果:6例术中顺利,出院后随访2月无并发症发生。结论:Muscle spare切口对术后... 目的:探讨Muscle spare切口在胸部手术中特殊情况下的应用。方法:对2011-01~2011-12收治必须或最适宜进行muscle spare开胸术患者的临床资料进行回顾总结。结果:6例术中顺利,出院后随访2月无并发症发生。结论:Muscle spare切口对术后引流量减少,平均住院日缩短,对肺功能较差的患者和老年患者具有更为重要的临床价值。 展开更多
关键词 胸部手术 MUSCLE spare切口
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GRACE Follow-On卫星的星载GNSS相位测速法 被引量:2
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作者 刘晗 魏辉 邹贤才 《测绘学报》 EI CSCD 北大核心 2021年第12期1772-1779,共8页
通常认为,低轨卫星的速度和加速度信息需要首先进行卫星精密定轨,再通过轨道微分法得到最终解算结果。本文基于GRACE Follow-On卫星的GPS载波相位观测数据,通过数值微分方法直接对载波进行微分,解算得到卫星的速度和加速度。基于2018-11... 通常认为,低轨卫星的速度和加速度信息需要首先进行卫星精密定轨,再通过轨道微分法得到最终解算结果。本文基于GRACE Follow-On卫星的GPS载波相位观测数据,通过数值微分方法直接对载波进行微分,解算得到卫星的速度和加速度。基于2018-11-01—2018-11-10的GRACE Follow-On C/D卫星实测数据进行了试验,利用CODE精密星历和5 s钟差产品,结果表明,当微分器长度设置为9点时,载波相位直接法确定C和D卫星速度的3D RMS分别可达0.2276 mm/s和0.2384 mm/s(微分间隔为60 s);确定卫星加速度的3D RMS分别可达4.1μm/s^(2)和4.5μm/s^(2)(微分间隔为90 s)。载波相位直接微分法相比于运动学轨道差分法而言,无须固定模糊度,削弱了轨道历元间相关性对其微分速度和加速度的影响,可为GRACE Follow-On任务的精密定轨和重力场解算提供高精度的速度和加速度信息。 展开更多
关键词 GRACE follow-on 星载GPS 载波相位 卫星加速度
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Collaborative optimization of maintenance and spare ordering of continuously degrading systems 被引量:6
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作者 Wei Zhou Dongfeng Wang +1 位作者 Jingyu Sheng Bo Guo 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2012年第1期63-70,共8页
A collaborative optimization model for maintenance and spare ordering of a single-unit degrading system is proposed in this paper based on the continuous detection. A gamma distribution is used to model the material d... A collaborative optimization model for maintenance and spare ordering of a single-unit degrading system is proposed in this paper based on the continuous detection. A gamma distribution is used to model the material degradation. The degrading decrement after the imperfect maintenance action is assumed as a random variable normal distribution. This model aims to ob- tain the optimal maintenance policy and spare ordering point with the expected cost rate within system lifecycle as the optimization objective. The rationality and feasibility of the model are proved through a numerical example. 展开更多
关键词 collaborative optimization maintenance spare order- ing degrading system.
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System optimization-oriented spare parts dynamic configuration model for multi-echelon multi-indenture system 被引量:9
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作者 Minzhi Ruan Hua Li Jian Fu 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2017年第5期923-933,共11页
In order to optimize the spares configuration project at different stages during the life cycle, the factor of time is considered to relax the assumption of the spares steady demand in multi-echelon technique for reco... In order to optimize the spares configuration project at different stages during the life cycle, the factor of time is considered to relax the assumption of the spares steady demand in multi-echelon technique for recoverable item control (METRIC) theory. According to the method of systems analysis, the dynamic palm theorem is introduced to establish the prediction model of the spares demand rate, and its main influence factors are analyzed, based on which, the spares support effectiveness evaluation index system is studied, and the system optimization-oriented spares dynamic configuration method for multi-echelon multi-indenture system is proposed. Through the analysis of the optimization algorithm, the layered marginal algorithm is designed to improve the model calculation efficiency. In a given example, the multi-stage spares configuration project during its life cycle is gotten, the research result conforms to the actual status, and it can provide a new way for the spares dynamic optimization. 展开更多
关键词 system optimization spare parts dynamic demand support effectiveness multi-echelon multi-indenture layered marginal algorithm
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Accurate and rapid error estimation on global gravitational field from current GRACE and future GRACE Follow-On missions 被引量:34
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作者 郑伟 许厚泽 +1 位作者 钟敏 员美娟 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第8期3597-3604,共8页
Firstly, the new combined error model of cumulative geoid height influenced by four error sources, including the inter-satellite range-rate of an interferometric laser (K-band) ranging system, the orbital position a... Firstly, the new combined error model of cumulative geoid height influenced by four error sources, including the inter-satellite range-rate of an interferometric laser (K-band) ranging system, the orbital position and velocity of a global positioning system (GPS) receiver and non-conservative force of an accelerometer, is established from the perspectives of the power spectrum principle in physics using the semi-analytical approach. Secondly, the accuracy of the global gravitational field is accurately and rapidly estimated based on the combined error model; the cumulative geoid height error is 1.985× 10^-1 m at degree 120 based on GRACE Level 1B measured observation errors of the year 2007 published by the US Jet Propulsion Laboratory (JPL), and the cumulative geoid height error is 5.825 × 10^-2 m at degree 360 using GRACE Follow-On orbital altitude 250 km and inter-satellite range 50 km. The matching relationship of accuracy indexes from GRACE Follow-On key payloads is brought forward, and the dependability of the combined error model is validated. Finally, the feasibility of high-accuracy and high-resolution global gravitational field estimation from GRACE Follow-On is demonstrated based on different satellite orbital altitudes. 展开更多
关键词 global gravitational field GRACE follow-on semi-analytical approach combined error model
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Joint optimization of maintenance inspection and spare provisioning for aircraft deteriorating parts 被引量:4
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作者 Jing Cai Xin Li Xi Chen 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2017年第6期1133-1140,共8页
With the wide application of condition based maintenance(CBM) in aircraft maintenance practice, the joint optimization of maintenance and inventory management, which can take full advantage of CBM and reduce the aircr... With the wide application of condition based maintenance(CBM) in aircraft maintenance practice, the joint optimization of maintenance and inventory management, which can take full advantage of CBM and reduce the aircraft operational cost, is receiving increasing attention. In order to optimize the inspection interval, maintenance decision and spare provisioning together for aircraft deteriorating parts, firstly, a joint inventory management strategy is presented, then, a joint optimization of maintenance inspection and spare provisioning for aircraft parts subject to the Wiener degradation process is proposed based on the strategy.Secondly, a combination of the genetic algorithm(GA) and the Monte Carol method is developed to minimize the total cost rate.Finally, a case study is conducted and the proposed joint optimization model is compared with the existing optimization model and the airline real case. The results demonstrate that the proposed model is more beneficial and effective. In addition, the sensitivity analysis of the proposed model shows that the lead time has higher influence on the optimal results than the urgent order cost and the corrective maintenance cost, which is consistent with the actual situation of aircraft maintenance practices and inventory management. 展开更多
关键词 joint optimization maintenance spare provision aircraft part Wiener process
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Proteomic analysis of the dorsal spinal cord in the mouse model of spared nerve injury-induced neuropathic pain 被引量:3
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作者 Eun-sung Park Jung-mo Ahn +4 位作者 Sang-min Jeon Hee-jung Cho Ki-myung Chung Je-yoel Cho Dong-ho Youn 《The Journal of Biomedical Research》 CAS CSCD 2017年第6期494-502,共9页
Peripheral nerve injury often causes neuropathic pain and is associated with changes in the expression of numerous proteins in the dorsal horn of the spinal cord. To date, proteomic analysis method has been used to si... Peripheral nerve injury often causes neuropathic pain and is associated with changes in the expression of numerous proteins in the dorsal horn of the spinal cord. To date, proteomic analysis method has been used to simultaneously analyze hundreds or thousands of proteins differentially expressed in the dorsal horn of the spinal cord in rats or dorsal root ganglion of rats with certain type of peripheral nerve injury. However, a proteomic study using a mouse model of neuropathic pain could be attempted because of abundant protein database and the availability of transgenic mice. In this study, whole proteins were extracted from the ipsilateral dorsal half of the 4th-6th lumbar spinal cord in a mouse model of spared nerve injury(SNI)-induced neuropathic pain. In-gel digests of the proteins size-separated on a polyacrylamide gel were subjected to reverse-phase liquid-chromatography coupled with electrospray ionization ion trap tandem mass spectrometry(MS/MS). After identifying proteins, the data were analyzed with subtractive proteomics using ProtAn, an in-house analytic program. Consequently, 15 downregulated and 35 upregulated proteins were identified in SNI mice. The identified proteins may contribute to the maintenance of neuropathic pain,and may provide new or valuable information in the discovery of new therapeutic targets for neuropathic pain. 展开更多
关键词 PROTEOMICS spinal dorsal horn neuropathic pain spared nerve injury MOUSE
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