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Cyber–Physical Power System (CPPS): A review on measures and optimization methods of system resilience

《工程管理前沿(英文)》 2021年 第8卷 第4期   页码 503-518 doi: 10.1007/s42524-021-0163-3

摘要: The Cyber–Physical Power System (CPPS) is one of the most critical infrastructure systems in a country because a stable and secure power supply is a key foundation for national and social development. In recent years, resilience has become a major topic in preventing and mitigating the risks caused by large-scale blackouts of CPPSs. Accordingly, the concept and significance of CPPS resilience are at first explained from the engineering perspective in this study. Then, a review of representative quantitative assessment measures of CPPS resilience applied in the existing literature is provided. On the basis of these assessment measures, the optimization methods of CPPS resilience are reviewed from three perspectives, which are mainly focused on the current research, namely, optimizing the recovery sequence of components, identifying and protecting critical nodes, and enhancing the coupling patterns between physical and cyber networks. The recent advances in modeling methods for cascading failures within the CPPS, which is the theoretical foundation for the resilience assessment and optimization research of CPPSs, are also presented. Lastly, the challenges and future research directions for resilience optimizing of CPPSs are discussed.

关键词: Cyber–Physical Power System     resilience assessment     resilience optimization     cascading failure modeling    

通过最小化边缘添加中的代数连接度来减少电网级联故障传播 Research Articles

Supaporn LONAPALAWONG1,颜姜哲2,李家雨3,叶德仕2,陈为1,汤涌4,黄彦浩4,王灿2

《信息与电子工程前沿(英文)》 2022年 第23卷 第3期   页码 382-397 doi: 10.1631/FITEE.2000596

摘要: 在各种情况下分析网络鲁棒性通常被认为是一个具有挑战性的问题。应对故障的鲁棒性是大型动态网络系统(如电力网、运输系统、通信系统和计算机网络)的基本特性之一。由于网络的多样性和复杂性,人们已提出许多拓扑特征以捕获系统特定属性。对于电网,通过拓扑设计提高网络结构鲁棒性是常见做法。然而,大多数现有方法集中于局部网络度量,例如节点连接度和边连接度,而非从全局视角看待电网中的级联传播。本文使用信息量大的全局度量代数连接度,因为它对谱图的全局连接度敏感。我们通过最小化代数连接度的增量以减少电网中的平均传播。提出一种基于拓扑的贪婪策略,以优化电网鲁棒性。为评估网络鲁棒性,使用MATCASC计算电网中级联故障中断的平均传播。实验结果表明,所提方法优于现有技术。

关键词: 网络鲁棒性;级联故障;平均传播;代数连接度;电网    

Uncertainty of concrete strength in shear and flexural behavior of beams using lattice modeling

《结构与土木工程前沿(英文)》 2023年 第17卷 第2期   页码 306-325 doi: 10.1007/s11709-022-0890-5

摘要: This paper numerically studied the effect of uncertainty and random distribution of concrete strength in beams failing in shear and flexure using lattice modeling, which is suitable for statistical analysis. The independent variables of this study included the level of strength reduction and the number of members with reduced strength. Three levels of material deficiency (i.e., 10%, 20%, 30%) were randomly introduced to 5%, 10%, 15%, and 20% of members. To provide a database and reliable results, 1000 analyses were carried out (a total of 24000 analyses) using the MATLAB software for each combination. Comparative studies were conducted for both shear- and flexure-deficit beams under four-point loading and results were compared using finite element software where relevant. Capability of lattice modeling was highlighted as an efficient tool to account for uncertainty in statistical studies. Results showed that the number of deficient members had a more significant effect on beam capacity compared to the level of strength deficiency. The scatter of random load-capacities was higher in flexure (range: 0.680–0.990) than that of shear (range: 0.795–0.996). Finally, nonlinear regression relationships were established with coefficient of correlation values (R2) above 0.90, which captured the overall load–deflection response and level of load reduction.

关键词: lattice modeling     shear failure     flexural failure     uncertainty     deficiency     numerical simulation    

Analysis of stress and failure in rock specimens with closed and open flaws on the surface

《结构与土木工程前沿(英文)》 2021年 第15卷 第5期   页码 1222-1237 doi: 10.1007/s11709-021-0773-1

摘要: The influence of closed and open surface flaws on the stress distribution and failure in rock specimens is investigated. Heterogeneous finite element models are developed to simulate the compression tests on flawed rock specimens. The simulated specimens include those with closed flaws and those with open flaws on the surface. Systematic analyses are conducted to investigate the influences of the flaw inclination, friction coefficient and the confining stress on failure behavior. Numerical results show significant differences in the stress, displacement, and failure behavior of the closed and open flaws when they are subjected to pure compression; however, their behaviors under shear and tensile loads are similar. According to the results, when compression is the dominant mode of stress applied to the flaw surface, an open flaw may play a destressing role in the rock and relocate the stress concentration and failure zones. The presented results in this article suggest that failure at the rock surface may be managed in a favorable manner by fabricating open flaws on the rock surface. The insights gained from this research can be helpful in managing failure at the boundaries of rock structures.

关键词: surface flaw     heterogeneity     circular hole     numerical modeling     relative displacement    

Theoretical study of failure in composite pressure vessels subjected to low-velocity impact and internal

Roham RAFIEE, Hossein RASHEDI, Shiva REZAEE

《结构与土木工程前沿(英文)》 2020年 第14卷 第6期   页码 1349-1358 doi: 10.1007/s11709-020-0650-3

摘要: A theoretical solution is aimed to be developed in this research for predicting the failure in internally pressurized composite pressure vessels exposed to low-velocity impact. Both in-plane and out-of-plane failure modes are taken into account simultaneously and thus all components of the stress and strain fields are derived. For this purpose, layer-wise theory is employed in a composite cylinder under internal pressure and low-velocity impact. Obtained stress/strain components are fed into appropriate failure criteria for investigating the occurrence of failure. In case of experiencing any in-plane failure mode, the evolution of damage is modeled using progressive damage modeling in the context of continuum damage mechanics. Namely, mechanical properties of failed ply are degraded and stress analysis is performed on the updated status of the model. In the event of delamination occurrence, the solution is terminated. The obtained results are validated with available experimental observations in open literature. It is observed that the sequence of in-plane failure and delamination varies by increasing the impact energy.

关键词: composite pressure vessel     low-velocity impact     failure     theoretical solution     progressive damage modeling    

Improvement of the cascading closed loop cycle system

ZHANG Guoqiang, CAI Ruixian

《能源前沿(英文)》 2007年 第1卷 第3期   页码 341-346 doi: 10.1007/s11708-007-0051-5

摘要: Aspen Plus was used to simulate and get more information about the cascading closed loop cycle (CCLC) system [1–3]. Following evaluation of the variable temperature heat source (e.g. gas turbine flue gas) utilized by the CCLC, both qualitative and quantitive comparisons between the system and simple steam Rankine cycle, were made. The results indicate that CCLC has the advantage in recuperating exergy from flue gas, but it cannot sufficiently convert the recuperated exergy to useful work. To improve the utilization of low temperature flue gas heat, the properties and parameters of the working substance must match conditions of the low temperature heat source. A better cycle scheme and pressure distribution was proposed to raise the efficiency of the CCLC. In addition, the multifunction system concept was introduced to improve the performance of CCLC with solar energy.

Lightweight design of an electric bus body structure with analytical target cascading

《机械工程前沿(英文)》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0718-y

摘要: Lightweight designs of new-energy vehicles can reduce energy consumption, thereby improving driving mileage. In this study, a lightweight design of a newly developed multi-material electric bus body structure is examined in combination with analytical target cascading (ATC). By proposing an ATC-based two-level optimization strategy, the original lightweight design problem is decomposed into the system level and three subsystem levels. The system-level optimization model is related to mass minimization with all the structural modal frequency constraints, while each subsystem-level optimization model is related to the sub-structural performance objective with sub-structure mass constraints. To enhance the interaction between two-level systems, each subsystem-level objective is reformulated as a penalty-based function coordinated with the system-level objective. To guarantee the accuracy of the model-based analysis, a finite element model is validated through experimental modal test. A sequential quadratic programming algorithm is used to address the defined optimization problem for effective convergence. Compared with the initial design, the total mass is reduced by 49 kg, and the torsional stiffness is increased by 17.5%. In addition, the obtained design is also validated through strength analysis.

关键词: electric vehicle     body in white (BIW)     lightweight     analytical target cascading (ATC)    

布尔控制网络的级联分解:一种图论方法 Research Articles

Yi-feng LI, Jian-dong ZHU

《信息与电子工程前沿(英文)》 2020年 第21卷 第2期   页码 304-315 doi: 10.1631/FITEE.1900422

摘要: 采用图论方法研究布尔控制网络的两类级联分解问题。提出嵌套完美等点划分(NPEVP)的概念。基于NPEVP,得到级联分解问题可解的充要图条件。给定提出的图条件,可构造性地得到实现相应级联分解形式的逻辑坐标变换。最后,给出两个实例以验证结论。

关键词: 布尔控制网络;半张量积;级联分解;图条件    

Nonlinear analysis and reliability of metallic truss structures

Karim BENYAHI, Youcef BOUAFIA, Salma BARBOURA, Mohand Said KACHI

《结构与土木工程前沿(英文)》 2018年 第12卷 第4期   页码 577-593 doi: 10.1007/s11709-017-0458-y

摘要: The present study goes into the search for the safety domain of civil engineering structures. The objective is to show how a reliability-evaluation brought by a mechanical sizing can be obtained. For that purpose, it is necessary to have a mechanical model and a reliability model representing correctly the behavior of this type of structure. It is a question on one hand, to propose a formulation for the nonlinear calculation (mechanical nonlinearity) of the spatial structures in trusses, and on the other hand, to propose or to adapt a formulation and a modeling of the reliability. The principle of Hasofer-Lind can be applied, in first approach, for the reliability index estimation, scenarios and the probability of failure. The made check concerned metallic in truss structures. Finally, some structures are calculated using the method adapted by Hasofer-Lind to validate the probability approach of the reliability analysis.

关键词: modeling     nonlinearity mechanical     truss     probability     reliability     response surface     probability of failure    

Integrated management of cardiac failure: the cardiac failure clinic

null

《医学前沿(英文)》 2011年 第5卷 第1期   页码 20-25 doi: 10.1007/s11684-011-0106-1

摘要:

The prevalence of the risk factors and the risk of cardiac failure are both increasing in China. This might be the consequence of the changes of the life conditions (emigration to the urban areas, changes in the diet and life style, lack of physical exercise, etc.). The wide range of clinical presentations of cardiac failure (acute or chronic) and of therapeutic approaches (medical or surgical) makes necessary the integration within the same structure of the various experts involved in the diagnosis and the treatment of cardiac diseases. Technologic and human resources required to offer all the options represent a multifaceted commitment which should be focused optimally in dedicated centers. In these centers, collaboration should replace competition between the medical and the surgical cardiac specialists. Development of team work should permit to optimize the cost efficacy of the treatments. Most of all, such a structure will facilitate the translation of innovative therapies between the research centers and clinical facilities.

关键词: cardiac failure     cardiac transplantation     mechanical circulatory support    

基于级联聚合算法下的布尔网络最优单点摄动 Research Articles

Jin-feng PAN, Min MENG

《信息与电子工程前沿(英文)》 2020年 第21卷 第2期   页码 294-303 doi: 10.1631/FITEE.1900411

摘要: 研究级联聚合算法分割下的大型布尔网络最优单点摄动问题;最大化期望吸引子吸引域,同时最小化非期望吸引子吸引域。首先,通过级联聚合算法给出一个在单点摄动下保持期望吸引子不变的充要条件。其次,提出一个判定是否出现新吸引子的算法。然后,提出另一算法给出单点摄动下吸引子吸引域的大小变化。最后,将本文理论应用于寻找T细胞受体网络的最优单点摄动问题。

关键词: 大型布尔网络;吸引子;级联聚合算法;单点摄动    

Progressive failure analysis of notched composite plate by utilizing macro mechanics approach

《结构与土木工程前沿(英文)》 2021年 第15卷 第3期   页码 623-642 doi: 10.1007/s11709-021-0726-8

摘要: In this study, gradual and sudden reduction methods were combined to simulate a progressive failure in notched composite plates using a macro mechanics approach. Using the presented method, a progressive failure is simulated based on a linear softening law prior to a catastrophic failure, and thereafter, sudden reduction methods are employed for modeling a progressive failure. This combination method significantly reduces the computational cost and is also capable of simultaneously predicting the first and last ply failures (LPFs) in composite plates. The proposed method is intended to predict the first ply failure (FPF), LPF, and dominant failure modes of carbon/epoxy and glass/epoxy notched composite plates. In addition, the effects of mechanical properties and different stacking sequences on the propagation of damage in notched composite plates were studied. The results of the presented method were compared with experimental data previously reported in the literature. By comparing the numerical and experimental data, it is revealed that the proposed method can accurately simulate the failure propagation in notched composite plates at a low computational cost.

关键词: progressive failure     notched composite plate     Hashin failure criterion     macro mechanics approach     finite element method    

Bending failure performance of a shield tunnel segment based on full-scale test and numerical analysis

《结构与土木工程前沿(英文)》   页码 1033-1046 doi: 10.1007/s11709-023-0973-y

摘要: This study focuses on the bending failure performance of a shield tunnel segment. A full-scale test was conducted to investigate deformation and failure characteristics. During the loading, the bending failure process can be divided into four stages: the elastic stage, working stage with cracks, failure stage, and ultimate stage. The characteristic loads between contiguous stages are the cracking, failure, and ultimate loads. A numerical model corresponding to the test was established using the elastoplastic damage constitutive model of concrete. After a comparative analysis of the simulation and test results, parametric studies were performed to discuss the influence of the reinforcement ratio and proportion of tensile longitudinal reinforcement on the bearing capacity. The results indicated that the change in the reinforcement ratio and the proportion of tensile longitudinal reinforcement had little effect on the cracking load but significantly influenced the failure and ultimate loads of the segment. It is suggested that in the reinforcement design of the subway segment, the reinforcement ratio and the proportion of tensile longitudinal reinforcement can be chosen in the range of 0.7%–1.2% and 49%–55%, respectively, allowing the segment to effectively use the reinforcement and exert the design strength, thereby improving the bearing capacity of the segment.

关键词: shield tunnel     bearing capacity     failure mechanism     segment reinforcement    

连锁故障中电力系统脆弱性的多图卷积网络分析 Research Article

Supaporn LONAPALAWONG1,陈长胜2,王灿3,陈为1

《信息与电子工程前沿(英文)》 2022年 第23卷 第12期   页码 1848-1861 doi: 10.1631/FITEE.2200035

摘要: 分析电力系统在连锁故障中的薄弱环节是电力系统分析领域极具挑战的难题。电力系统领域的传统分析方法虽能发现一些简单的传播规律,但却难以捕捉不同运行条件下的复杂细节。近年来的研究引入了深度学习算法来解决这一难题。然而,现有基于深度学习的方法大多仅从拓扑层面考虑电力系统的网架结构,未能充分考虑空间信息(如电距离)以提高图卷积过程的精确度。鉴于此,本文提出一种新型电力系统加权线图,综合考虑电力系统拓扑结构和空间信息,大幅优化线图的边权分配。此外,本文提出一种基于图分类任务的多图卷积网络(MGCN),在保留电力系统空间相关性的同时有效捕获物理元件之间的关联。经验证,该模型能够在具有额外拓扑特征的建模系统中保持理想精度,从而更好地分析存在并行输电线路的复杂连锁故障。最后,本文采用逐层相关传播方法解释MGCN,并量化了模型分类的贡献因子,有效提升模型的可解释性。

关键词: 电力系统;脆弱性;连锁故障;多图卷积网络;加权线图    

Overview on acute-on-chronic liver failure

null

《医学前沿(英文)》 2016年 第10卷 第1期   页码 1-17 doi: 10.1007/s11684-016-0439-x

摘要:

Liver failure (LF) is defined as severe dysfunction in hepatic synthesis, detoxification, and metabolism induced by various etiologies. Clinical presentation of LF typically includes severe jaundice, coagulation disorder, hepatic encephalopathy, and ascites. LF can be classified into acute LF, acute-on-chronic LF (ACLF), and chronic LF. ACLF has been demonstrated as a distinct syndrome with unique clinical presentation and outcomes. The severity, curability, and reversibility of ACLF have attracted considerable attention. Remarkable developments in ACLF-related conception, diagnostic criteria, pathogenesis, and therapy have been achieved. However, this disease, especially its diagnostic criteria, remains controversial. In this paper, we systemically reviewed the current understanding of ACLF from its definition, etiology, pathophysiology, pathology, and clinical presentation to management by thoroughly comparing important findings between east and west countries, as well as those from other regions. We also discussed the controversies, challenges, and needs for future studies to promote the standardization and optimization of the diagnosis and treatment for ACLF.

关键词: liver failure     chronic liver failure     acute-on-chronic liver failure     diagnosis     prognosis     treatment    

标题 作者 时间 类型 操作

Cyber–Physical Power System (CPPS): A review on measures and optimization methods of system resilience

期刊论文

通过最小化边缘添加中的代数连接度来减少电网级联故障传播

Supaporn LONAPALAWONG1,颜姜哲2,李家雨3,叶德仕2,陈为1,汤涌4,黄彦浩4,王灿2

期刊论文

Uncertainty of concrete strength in shear and flexural behavior of beams using lattice modeling

期刊论文

Analysis of stress and failure in rock specimens with closed and open flaws on the surface

期刊论文

Theoretical study of failure in composite pressure vessels subjected to low-velocity impact and internal

Roham RAFIEE, Hossein RASHEDI, Shiva REZAEE

期刊论文

Improvement of the cascading closed loop cycle system

ZHANG Guoqiang, CAI Ruixian

期刊论文

Lightweight design of an electric bus body structure with analytical target cascading

期刊论文

布尔控制网络的级联分解:一种图论方法

Yi-feng LI, Jian-dong ZHU

期刊论文

Nonlinear analysis and reliability of metallic truss structures

Karim BENYAHI, Youcef BOUAFIA, Salma BARBOURA, Mohand Said KACHI

期刊论文

Integrated management of cardiac failure: the cardiac failure clinic

null

期刊论文

基于级联聚合算法下的布尔网络最优单点摄动

Jin-feng PAN, Min MENG

期刊论文

Progressive failure analysis of notched composite plate by utilizing macro mechanics approach

期刊论文

Bending failure performance of a shield tunnel segment based on full-scale test and numerical analysis

期刊论文

连锁故障中电力系统脆弱性的多图卷积网络分析

Supaporn LONAPALAWONG1,陈长胜2,王灿3,陈为1

期刊论文

Overview on acute-on-chronic liver failure

null

期刊论文