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时变可靠度 3

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Analysis of dispatching rules in a stochastic dynamic job shop manufacturing system with sequence-dependentsetup times

Pankaj SHARMA,Ajai JAIN

《机械工程前沿（英文）》 2014年第9卷第4期页码 380-389 doi: 10.1007/s11465-014-0315-9

摘要：

Stochastic dynamic job shop scheduling problem with consideration of sequence-dependent setup times are among the most difficult classes of scheduling problems. This paper assesses the performance of nine dispatching rules in such shop from makespan, mean flow time, maximum flow time, mean tardiness, maximum tardiness, number of tardy jobs, total setups and mean setup time performance measures viewpoint. A discrete event simulation model of a stochastic dynamic job shop manufacturing system is developed for investigation purpose. Nine dispatching rules identified from literature are incorporated in the simulation model. The simulation experiments are conducted under due date tightness factor of 3, shop utilization percentage of 90 % and setup times less than processing times. Results indicate that shortest setup time (SIMSET) rule provides the best performance for mean flow time and number of tardy jobs measures. The job with similar setup and modified earliest due date (JMEDD) rule provides the best performance for makespan, maximum flow time, mean tardiness, maximum tardiness, total setups and mean setup time measures.

关键词： scheduling stochastic dynamic job shop sequence-dependent setup times dispatching rule simulation

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Determination of the feasible setup parameters of a workpiece to maximize the utilization of a five-axis

Aqeel AHMED, Muhammad WASIF, Anis FATIMA, Liming WANG, Syed Amir IQBAL

《机械工程前沿（英文）》 2021年第16卷第2期页码 298-314 doi: 10.1007/s11465-020-0621-3

摘要： The machining industry must maximize the machine tool utilization for its efficient and effective usage. Determining a feasible workpiece location is one of the significant tasks performed in an iterative way via machining simulations. The maximum utilization of five-axis machine tools depends upon the cutting system’s geometry, the configuration of the machine tool, and the workpiece’s location. In this research, a mathematical model has been developed to determine the workpiece’s feasible location in the five-axis machine tool for avoiding the number of iterations, which are usually performed to eliminate the global collision and axis limit errors. In this research, a generic arrangement of the five-axis machine tool has been selected. The mathematical model of post-processor has been developed by using kinematic modeling methods. The machine tool envelopes have been determined using the post-processor and axial limit. The tooltip reachable workspace is determined by incorporating the post-processor, optimal cutting system length, and machining envelope, thereby further developing an algorithm to determine the feasible workpiece setup parameters accurately. The algorithm’s application has been demonstrated using an example. Finally, the algorithm is validated for feasible workpiece setup parameters in a virtual environment. This research is highly applicable in the industry to eliminate the number of iterations performed for the suitable workpiece setup parameters.

关键词： workpiece setup parameter five-axis space utilization setup parameters machine tool

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Finite element model updating of a large structure using multi-setup stochastic subspace identification

Reza KHADEMI-ZAHEDI, Pouyan ALIMOURI

《结构与土木工程前沿（英文）》 2019年第13卷第4期页码 965-980 doi: 10.1007/s11709-019-0530-x

摘要： In the present contribution, operational modal analysis in conjunction with bees optimization algorithm are utilized to update the finite element model of a solar power plant structure. The physical parameters which required to be updated are uncertain parameters including geometry, material properties and boundary conditions of the aforementioned structure. To determine these uncertain parameters, local and global sensitivity analyses are performed to increase the solution accuracy. An objective function is determined using the sum of the squared errors between the natural frequencies calculated by finite element method and operational modal analysis, which is optimized using bees optimization algorithm. The natural frequencies of the solar power plant structure are estimated by multi-setup stochastic subspace identification method which is considered as a strong and efficient method in operational modal analysis. The proposed algorithm is efficiently implemented on the solar power plant structure located in Shahid Chamran university of Ahvaz, Iran, to update parameters of its finite element model. Moreover, computed natural frequencies by numerical method are compared with those of the operational modal analysis. The results indicate that, bees optimization algorithm leads accurate results with fast convergence.

关键词： operational modal analysis solar power plant structure multi-setup stochastic subspace bees optimization algorithm sensitivity analysis

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Ant colony optimization for assembly sequence planning based on parameters optimization

Zunpu HAN, Yong WANG, De TIAN

《机械工程前沿（英文）》 2021年第16卷第2期页码 393-409 doi: 10.1007/s11465-020-0613-3

摘要： As an important part of product design and manufacturing, assembly sequence planning (ASP) has a considerable impact on product quality and manufacturing costs. ASP is a typical NP-complete problem that requires effective methods to find the optimal or near-optimal assembly sequence. First, multiple assembly constraints and rules are incorporated into an assembly model. The assembly constraints and rules guarantee to obtain a reasonable assembly sequence. Second, an algorithm called SOS-ACO that combines symbiotic organisms search (SOS) and ant colony optimization (ACO) is proposed to calculate the optimal or near-optimal assembly sequence. Several of the ACO parameter values are given, and the remaining ones are adaptively optimized by SOS. Thus, the complexity of ACO parameter assignment is greatly reduced. Compared with the ACO algorithm, the hybrid SOS-ACO algorithm finds optimal or near-optimal assembly sequences in fewer iterations. SOS-ACO is also robust in identifying the best assembly sequence in nearly every experiment. Lastly, the performance of SOS-ACO when the given ACO parameters are changed is analyzed through experiments. Experimental results reveal that SOS-ACO has good adaptive capability to various values of given parameters and can achieve competitive solutions.

关键词： assembly sequence planning ant colony optimization symbiotic organisms search parameter optimization

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Applicability of high dimensional model representation correlations for ignition delay times of n-heptane

Wang LIU, Jiabo ZHANG, Zhen HUANG, Dong HAN

《能源前沿（英文）》 2019年第13卷第2期页码 367-376 doi: 10.1007/s11708-018-0584-9

摘要： It is difficult to predict the ignition delay times for fuels with the two-stage ignition tendency because of the existence of the nonlinear negative temperature coefficient (NTC) phenomenon at low temperature regimes. In this paper, the random sampling-high dimensional model representation (RS-HDMR) methods were employed to predict the ignition delay times of n-heptane/air mixtures, which exhibits the NTC phenomenon, over a range of initial conditions. A detailed n-heptane chemical mechanism was used to calculate the fuel ignition delay times in the adiabatic constant-pressure system, and two HDMR correlations, the global correlation and the stepwise correlations, were then constructed. Besides, the ignition delay times predicted by both types of correlations were validated against those calculated using the detailed chemical mechanism. The results showed that both correlations had a satisfactory prediction accuracy in general for the ignition delay times of the n-heptane/air mixtures and the stepwise correlations exhibited a better performance than the global correlation in each subdomain. Therefore, it is concluded that HDMR correlations are capable of predicting the ignition delay times for fuels with two-stage ignition behaviors at low-to-intermediate temperature conditions.

关键词： ignition delay random sampling high dimensional model representation n-heptane fuel kinetics

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碳中和愿景下的中国能源转型之路 Article

张枢, 陈文颖

《工程（英文）》 2022年第14卷第7期页码 64-76 doi: 10.1016/j.eng.2021.09.004

摘要：本文利用能源-环境-经济模型China TIMES，设计了4个面向碳中和的能源转型情景，对因实现碳达峰时间不同和2050年碳排放量不同引起的转型路径差异进行了比较。

关键词：碳中和能源转型气候变化减缓 China TIMES模型协同效应

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Rolling-element bearings in China: From ancient times to the 20th century

Lie SUN,Ang LI

《机械工程前沿（英文）》 2016年第11卷第1期页码 33-43 doi: 10.1007/s11465-016-0373-2

摘要：

The development of rolling-element bearings in China has spanned a long period. Based on several typical and important cases, the present article reconstructs the history of rolling-element bearings in China by dividing it into four stages according to the various characteristics of the bearings. The first stage represents the origin of rolling bearings in China, which remains controversial because of several suspected races and cages that were likely the components of bearings more than a millennium ago. At the second stage, a type of simple roller bearing was used for astronomical instruments not later than the 13th century based on clear philological and physical evidence. A similar bearing was also applied to an abridged armillary in the 17th century. Another type of spherical thrust bearings with rolling elements, which is a key component of a traditional Chinese windmill, could support a rotating shaft that moves rotationally and at an angle. At the third stage, the Chinese began studying and using the so-called European-style bearing since the 17th century. Moreover, over the last 100 years, the modern rolling bearing industry was gradually established in China, particularly because of the technology transfer from the Soviet Union in the 1950s. At the fourth stage, the Chinese government initiated the relatively rapid development of bearing technology. The government launched the “bearing movement” from the 1950s to the 1960s to establish the modern bearing industry and to promote rolling bearings as replacement for traditional sliding bearings. Furthermore, a number of large professional factories and institutions in China have continually introduced advanced technology and equipment. At present, these companies and institutions play a significant role in the international bearing industry.

关键词： bearing movement rolling-element bearing China early rolling bearings technology transfer

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Data-driven approach to solve vertical drain under time-dependent loading

《结构与土木工程前沿（英文）》 2021年第15卷第3期页码 696-711 doi: 10.1007/s11709-021-0727-7

摘要： Currently, the vertical drain consolidation problem is solved by numerous analytical solutions, such as time-dependent solutions and linear or parabolic radial drainage in the smear zone, and no artificial intelligence (AI) approach has been applied. Thus, in this study, a new hybrid model based on deep neural networks (DNNs), particle swarm optimization (PSO), and genetic algorithms (GAs) is proposed to solve this problem. The DNN can effectively simulate any sophisticated equation, and the PSO and GA can optimize the selected DNN and improve the performance of the prediction model. In the present study, analytical solutions to vertical drains in the literature are incorporated into the DNN–PSO and DNN–GA prediction models with three different radial drainage patterns in the smear zone under time-dependent loading. The verification performed with analytical solutions and measurements from three full-scale embankment tests revealed promising applications of the proposed approach.

关键词： vertical drain artificial neural network time-dependent loading deep learning network genetic algorithm particle swarm optimization

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Effect of 2,5-dimethylfuran addition on ignition delay times of n-heptane at high temperatures

Zhenhua GAO, Erjiang HU, Zhaohua XU, Geyuan YIN, Zuohua HUANG

《能源前沿（英文）》 2019年第13卷第3期页码 464-473 doi: 10.1007/s11708-019-0609-z

摘要： The shock tube autoignition of 2,5-dimethylfuran (DMF)/n-heptane blends (DMF0-100%, by mole fraction) with equivalence ratios of 0.5, 1.0, and 2.0 over the temperature range of 1200–1800 K and pressures of 2.0 atm and 10.0 atm were investigated. A detailed blend chemical kinetic model resulting from the merging of validated kinetic models for the components of the fuel blends was developed. The experimental observations indicate that the ignition delay times nonlinearly increase with an increase in the DMF addition level. Chemical kinetic analysis including radical pool analysis and flux analysis were conducted to explain the DMF addition effects. The kinetic analysis shows that at lower DMF blending levels, the two fuels have negligible impacts on the consumption pathways of each other. As the DMF addition increases to relatively higher levels, the consumption path of n-heptane is significantly changed due to the competition of small radicals, which primarily leads to the nonlinear increase in the ignition delay times of DMF/n-heptane blends.

关键词： ignition delay time shock tube kinetic model 2 5-dimethylfuran (DMF) n-heptane

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Chloride binding and time-dependent surface chloride content models for fly ash concrete

S. MUTHULINGAM,B. N. RAO

《结构与土木工程前沿（英文）》 2016年第10卷第1期页码 112-120 doi: 10.1007/s11709-015-0322-x

摘要： Corrosion of embedded rebars is a classical deterioration mechanism of reinforced concrete structures exposed to chloride environments. Such environments can be attributed to the presence of seawater, deicing or sea-salts, which have high concentrations of chloride ion. Chloride ingress into concrete, essential for inducing rebar corrosion, is a complex interaction between many physical and chemical processes. The current study proposes two chloride ingress parameter models for fly ash concrete, namely: 1) surface chloride content under tidal exposure condition; and 2) chloride binding. First, inconsistencies in surface chloride content and chloride binding models reported in literature, due to them not being in line with past research studies, are pointed out. Secondly, to avoid such inconsistencies, surface chloride content and chloride binding models for fly ash concrete are proposed based upon the experimental work done by other researchers. It is observed that, proposed models are simple, consistent and in line with past research studies reported in literature.

关键词： binding isotherms chloride ingress concrete fly ash surface chloride content

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基于petri网装配序列灰色聚类决策研究

莫茜,罗毅

《中国工程科学》 2008年第10卷第11期页码 65-68

摘要：

利用petri网直观图形化特点建立装配模型，并根据petri网原理得出可行装配序列。影响可行装配序列的大部分因素是定性的、模糊的、非数值的，将装配序列看作灰色系统，采用灰色聚类决策方法对可行序列进行评估。分析了影响因素的灰色分类并且研究了灰色聚类决策步骤。实例分析表明，该方法为petri网原理所得可行序列进行正确的评估并且得出决策向量。

关键词：装配序列 petri网灰色聚类决策

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论新时代的创新人才

甘自恒,金又琳

《中国工程科学》 2007年第9卷第11期页码 26-34

摘要：

阐明了研究新时代创新人才的重大意义，揭示了新时代的内涵：以创新为时代精神，包括从多种视角揭示的和平发展时代，生态文明时代，知识经济时代，政冶多极化时代，创意文化时代，改革开放时代；把新时代的创新人才分为4类：一般创新人才，拔尖创新人才，杰出创新人才，大师级创新人才；概括了新时代创新人才的5个基本特征：观念的时代性，素质的全面性，导向的先进性，研究的综合性，成果的创新性；总结了新时代创新人才的成才模式，阐述了研究新时代创新人才对高等教育创新的启示和建议。

关键词：新时代一般创新人才拔尖创新人才杰出创新人才大师级创新人才

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Transforming bacterial disease surveillance and investigation using whole-genome sequence to probe the

null

《医学前沿（英文）》 2018年第12卷第1期页码 23-33 doi: 10.1007/s11684-017-0607-7

摘要：

Two decades have passed since the first bacterial whole-genome sequencing, which provides new opportunity for microbial genome. Consequently, considerable genetic diversity encoded by bacterial genomes and among the strains in the same species has been revealed. In recent years, genome sequencing techniques and bioinformatics have developed rapidly, which has resulted in transformation and expedited the application of strategy and methodology for bacterial genome comparison used in dissection of infectious disease epidemics. Bacterial whole-genome sequencing and bioinformatic computing allow genotyping to satisfy the requirements of epidemiological study in disease control. In this review, we outline the significance and summarize the roles of bacterial genome sequencing in the context of bacterial disease control and prevention. We discuss the applications of bacterial genome sequencing in outbreak detection, source tracing, transmission mode discovery, and new epidemic clone identification. Wide applications of genome sequencing and data sharing in infectious disease surveillance networks will considerably promote outbreak detection and early warning to prevent the dissemination of bacterial diseases.

关键词： genome sequencing genomic epidemiology bacteria surveillance infectious diseases

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GDF15 negatively regulates chemosensitivity via TGFBR2-AKT pathway-dependent metabolism in esophageal

《医学前沿（英文）》 2023年第17卷第1期页码 119-131 doi: 10.1007/s11684-022-0949-7

摘要： Treating patients with esophageal squamous cell carcinoma (ESCC) is challenging due to the high chemoresistance. Growth differentiation factor 15 (GDF15) is crucial in the development of various types of tumors and negatively related to the prognosis of ESCC patients according to our previous research. In this study, the link between GDF15 and chemotherapy resistance in ESCC was further explored. The relationship between GDF15 and the chemotherapy response was investigated through in vitro and in vivo studies. ESCC patients with high levels of GDF15 expression showed an inferior chemotherapeutic response. GDF15 improved the tolerance of ESCC cell lines to low-dose cisplatin by regulating AKT phosphorylation via TGFBR2. Through an in vivo study, we further validated that the anti-GDF15 antibody improved the tumor inhibition effect of cisplatin. Metabolomics showed that GDF15 could alter cellular metabolism and enhance the expression of UGT1A. AKT and TGFBR2 inhibition resulted in the reversal of the GDF15-induced expression of UGT1A, indicating that TGFBR2-AKT pathway-dependent metabolic pathways were involved in the resistance of ESCC cells to cisplatin. The present investigation suggests that a high level of GDF15 expression leads to ESCC chemoresistance and that GDF15 can be targeted during chemotherapy, resulting in beneficial therapeutic outcomes.

关键词： GDF15 esophageal squamous cell carcinoma chemoresistance cellular metabolism TGFBR2 AKT