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Identification of structural parameters and boundary conditions using a minimum number of measurement points

Ali KARIMPOUR, Salam RAHMATALLA

《结构与土木工程前沿(英文)》 2020年 第14卷 第6期   页码 1331-1348 doi: 10.1007/s11709-020-0686-4

摘要: This article proposes a novel methodology that uses mathematical and numerical models of a structure to build a data set and determine crucial nodes that possess the highest sensitivity. Regression surfaces between the structural parameters and structural output features, represented by the natural frequencies of the structure and local transmissibility, are built using the numerical data set. A description of a possible experimental application is provided, where sensors are mounted at crucial nodes, and the natural frequencies and local transmissibility at each natural frequency are determined from the power spectral density and the power spectral density ratios of the sensor responses, respectively. An inverse iterative process is then applied to identify the structural parameters by matching the experimental features with the available parameters in the myriad numerical data set. Three examples are presented to demonstrate the feasibility and efficacy of the proposed methodology. The results reveal that the method was able to accurately identify the boundary coefficients and physical parameters of the Euler-Bernoulli beam as well as a highway bridge model with elastic foundations using only two measurement points. It is expected that the proposed method will have practical applications in the identification and analysis of restored structural systems with unknown parameters and boundary coefficients.

关键词: structural model validation     eigenvalue problem     response surface     inverse problems    

Robust cooperation of connected vehicle systems with eigenvalue-bounded interaction topologies in the

Keqiang LI, Feng GAO, Shengbo Eben LI, Yang ZHENG, Hongbo GAO

《机械工程前沿(英文)》 2018年 第13卷 第3期   页码 354-367 doi: 10.1007/s11465-018-0486-x

摘要:

This study presents a distributed H-infinity control method for uncertain platoons with dimensionally and structurally unknown interaction topologies provided that the associated topological eigenvalues are bounded by a predesigned range. With an inverse model to compensate for nonlinear powertrain dynamics, vehicles in a platoon are modeled by third-order uncertain systems with bounded disturbances. On the basis of the eigenvalue decomposition of topological matrices, we convert the platoon system to a norm-bounded uncertain part and a diagonally structured certain part by applying linear transformation. We then use a common Lyapunov method to design a distributed H-infinity controller. Numerically, two linear matrix inequalities corresponding to the minimum and maximum eigenvalues should be solved. The resulting controller can tolerate interaction topologies with eigenvalues located in a certain range. The proposed method can also ensure robustness performance and disturbance attenuation ability for the closed-loop platoon system. Hardware-in-the-loop tests are performed to validate the effectiveness of our method.

关键词: automated vehicles     platoon     distributed control     robustness    

基于有序特征值矩阵的对称变量检测算法 Article

Xiao-hua LI, Ji-zhong SHEN

《信息与电子工程前沿(英文)》 2017年 第18卷 第10期   页码 1644-1653 doi: 10.1631/FITEE.1601052

摘要: 为简化布尔函数中12类对称变量的检测过程,本文提出基于最小项展开或真值表的对称性检测新算法。首先,根据逻辑变量的对称性定义,定义基于真值表的有序特征值矩阵。通过分析12类对称变量有序特征值矩阵的约束条件,提出对称变量检测算法。该算法适用于含无关项布尔函数和不含无关项布尔函数中的对称变量检测。该算法避免了图形方法、谱系数方法、与—异或方法中的变量数限制,也解决了快速算法中的完备性问题。算法用C语言实现并对MCNC91标准电路进行测试。结果表明,与传统方法相比,新算法在适用的变量数、检测含无关项布尔函数、检测类型、检测过程复杂度方面是最优算法。

关键词: 布尔函数;对称变量;布尔逻辑代数系统;有序特征值矩阵;真值表    

Discussion on Problem-Based Engineering Management System

Qiao Xiang

《工程管理前沿(英文)》 2015年 第2卷 第3期   页码 249-260 doi: 10.15302/J-FEM-2015054

摘要: The paper puts forward the idea of problem-based engineering management, expounds its connotation and guiding ideology and moreover, substantially demonstrates its practical significance in the engineering management system for the maintenance of Chinese military aircraft engines.

关键词: problem     engineering management     system    

Airline planning and scheduling: Models and solution methodologies

Lei ZHOU, Zhe LIANG, Chun-An CHOU, Wanpracha Art CHAOVALITWONGSE

《工程管理前沿(英文)》 2020年 第7卷 第1期   页码 1-26 doi: 10.1007/s42524-020-0093-5

摘要: The airline industry is a representative industry with high cost and low profitability. Therefore, airlines should carefully plan their schedules to ensure that overall profit is maximized. We review the literature on airline planning and scheduling and focus on mathematical formulations and solution methodologies. Our research framework is anchored on three major problems in the airline scheduling, namely, fleet assignment, aircraft routing, and crew scheduling. General formulation, widely used solution approaches, and important extensions are presented for each problem and integrated problems. We conclude the review by identifying promising areas for further research.

关键词: airline planning     fleet assignment problem     aircraft routing problem     crew pairing problem     crew rostering problem     crew scheduling problem     integrated planning    

A solution to stochastic unit commitment problem for a wind-thermal system coordination

B. SARAVANAN,Shreya MISHRA,Debrupa NAG

《能源前沿(英文)》 2014年 第8卷 第2期   页码 192-200 doi: 10.1007/s11708-014-0306-x

摘要: Unit commitment (UC) problem is one of the most important decision making problems in power system. In this paper the UC problem is solved by considering it as a real time problem by adding stochasticity in the generation side because of wind-thermal co-ordination system as well as stochasticity in the load side by incorporating the randomness of the load. The most important issue that needs to be addressed is the achievement of an economic unit commitment solution after solving UC as a real time problem. This paper proposes a hybrid approach to solve the stochastic unit commitment problem considering the volatile nature of wind and formulating the UC problem as a chance constrained problem in which the load is met with high probability over the entire time period.

关键词: unit commitment (UC)     randomness     wind generation     univariate     chance constrained    

Solving unit commitment problem using a novel version of harmony search algorithm

Roozbeh MORSALI,Tohid JAFARI,Amirhossein GHODS,Mohammad KARIMI

《能源前沿(英文)》 2014年 第8卷 第3期   页码 297-304 doi: 10.1007/s11708-014-0309-7

摘要: In this context, a novel structure was proposed for improving harmony search (HS) algorithm to solve the unit comment (UC) problem. The HS algorithm obtained optimal solution for defined objective function by improvising, updating and checking operators. In the proposed improved self-adaptive HS (SGHS) algorithm, two important control parameters were adjusted to reach better solution from the simple HS algorithm. The objective function of this study consisted of operation, start-up and shut-down costs. To confirm the effectiveness, the SGHS algorithm was tested on systems with 10, 20, 40 and 60 generating units, and the obtained results were compared with those of the simple HS algorithm and other related works.

关键词: generation scheduling     harmony search (HS) algorithm     intelligent technique     unit commitment    

Transient analysis of thermoelastic contact problem of disk brakes

Ali BELHOCINE, Mostefa BOUCHETARA

《机械工程前沿(英文)》 2013年 第8卷 第2期   页码 150-159 doi: 10.1007/s11465-013-0266-6

摘要:

The main purpose of this study is to analyze the thermomechanical behavior of the dry contact between the brake disk and pads during the braking phase. The simulation strategy is based on computer code ANSYS11. The modeling of transient temperature in the disk is actually used to identify the factor of geometric design of the disk to install the ventilation system in vehicles. The thermal-structural analysis is then used with coupling to determine the deformation established and the Von Mises stresses in the disk, the contact pressure distribution in pads. The results are satisfactory compared to those found in the literature.

关键词: brake disks     heat flux     heat-transfer coefficient     Von Mises stress     contact pressure    

A solution to the unit commitment problem—a review

B. SARAVANAN, Siddharth DAS, Surbhi SIKRI, D. P. KOTHARI

《能源前沿(英文)》 2013年 第7卷 第2期   页码 223-236 doi: 10.1007/s11708-013-0240-3

摘要: Unit commitment (UC) is an optimization problem used to determine the operation schedule of the generating units at every hour interval with varying loads under different constraints and environments. Many algorithms have been invented in the past five decades for optimization of the UC problem, but still researchers are working in this field to find new hybrid algorithms to make the problem more realistic. The importance of UC is increasing with the constantly varying demands. Therefore, there is an urgent need in the power sector to keep track of the latest methodologies to further optimize the working criterions of the generating units. This paper focuses on providing a clear review of the latest techniques employed in optimizing UC problems for both stochastic and deterministic loads, which has been acquired from many peer reviewed published papers. It has been divided into many sections which include various constraints based on profit, security, emission and time. It emphasizes not only on deregulated and regulated environments but also on renewable energy and distributed generating systems. In terms of contributions, the detailed analysis of all the UC algorithms has been discussed for the benefit of new researchers interested in working in this field.

关键词: unit commitment (UC)     optimization     deterministic load     stochastic load     evolutionary programming (EP)     hybrid    

Hydrocele of the canal of Nuck — an old problem revisited

null

《医学前沿(英文)》 2013年 第7卷 第4期   页码 517-519 doi: 10.1007/s11684-013-0300-4

摘要:

Herein the authors describe the case of a young woman presenting with a tender lump in her groin. Clinically the differential was of either a reactive lymph node or a femoral hernia. Ultrasound scan was urgently arranged and showed a cystic lesion. Surgical exploration was carried out and revealed this to be a hydrocele of the canal of Nuck. This was excised and the patient’s symptoms resolved and she was discharged home the following day. We explore the embryology, pathophysiology and management of this rare entity.

关键词: canal of Nuck     hernia     embryology    

A solution to unit commitment problem using invasive weed optimization algorithm

B. SARAVANAN, E. R. VASUDEVAN, D. P. KOTHARI

《能源前沿(英文)》 2013年 第7卷 第4期   页码 487-494 doi: 10.1007/s11708-013-0279-1

摘要: Unit commitment (UC) is one of the most important aspect of power generation in the world today. Though, there is no method to find the exact optimized solution, there exists several meta-heuristic algorithms to determine the close to exact solution. This paper proposes a novel solution to effectively determine UC and generation cost using the technique of invasive weed optimization (IWO). The existing technique distributes the load demand among all the generating units. The method proposed here utilizes the output of UC obtained by using the Lagrangian relaxation (LR) method and calculates the required generation from only the plants that are ON discarding the OFF generator units and thereby giving a faster and more accurate response. Moreover, the results show the comparison between the LR-particle swarm optimization (PSO) and LR-IWO, and prove that the cost of generation for a 4 unit, 8 hour schedule is much less in the case of IWO when compared to PSO.

关键词: Lagrangian relaxation (LR)     invasive weed optimization (IWO)     economic dispatch     optimization     fuel cost     seed     fitness    

Method for solving the nonlinear inverse problem in gas face seal diagnosis based on surrogate models

《机械工程前沿(英文)》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0689-z

摘要: Physical models carry quantitative and explainable expert knowledge. However, they have not been introduced into gas face seal diagnosis tasks because of the unacceptable computational cost of inferring the input fault parameters for the observed output or solving the inverse problem of the physical model. The presented work develops a surrogate-model-assisted method for solving the nonlinear inverse problem in limited physical model evaluations. The method prepares a small initial database on sites generated with a Latin hypercube design and then performs an iterative routine that benefits from the rapidity of the surrogate models and the reliability of the physical model. The method is validated on simulated and experimental cases. Results demonstrate that the method can effectively identify the parameters that induce the abnormal signal output with limited physical model evaluations. The presented work provides a quantitative, explainable, and feasible approach for identifying the cause of gas face seal contact. It is also applicable to mechanical devices that face similar difficulties.

关键词: surrogate model     gas face seal     fault diagnosis     nonlinear dynamics     tribology    

A new technique for solving the multi-objective optimization problem using hybrid approach

Mimoun YOUNES,Khodja FOUAD,Belabbes BAGDAD

《能源前沿(英文)》 2014年 第8卷 第4期   页码 490-503 doi: 10.1007/s11708-014-0311-0

摘要: Energy efficiency, which consists of using less energy or improving the level of service to energy consumers, refers to an effective way to provide overall energy. But its increasing pressure on the energy sector to control greenhouse gases and to reduce CO emissions forced the power system operators to consider the emission problem as a consequential matter besides the economic problems. The economic power dispatch problem has, therefore, become a multi-objective optimization problem. Fuel cost, pollutant emissions, and system loss should be minimized simultaneously while satisfying certain system constraints. To achieve a good design with different solutions in a multi-objective optimization problem, fuel cost and pollutant emissions are converted into single optimization problem by introducing penalty factor. Now the power dispatch is formulated into a bi-objective optimization problem, two objectives with two algorithms, firefly algorithm for optimization the fuel cost, pollutant emissions and the real genetic algorithm for minimization of the transmission losses. In this paper the new approach (firefly algorithm-real genetic algorithm, FFA-RGA) has been applied to the standard IEEE 30-bus 6-generator. The effectiveness of the proposed approach is demonstrated by comparing its performance with other evolutionary multi-objective optimization algorithms. Simulation results show the validity and feasibility of the proposed method.

关键词: economic power dispatch (EPD)     firefly algorithm (FFA)     real genetic algorithm (RGA)     hybrid method    

Two-level uncapacitated lot-sizing problem considering the financing cost of working capital requirement

Yuan BIAN, David LEMOINE, Thomas G. YEUNG, Nathalie BOSTEL

《工程管理前沿(英文)》 2020年 第7卷 第2期   页码 248-258 doi: 10.1007/s42524-019-0069-5

摘要: During financial crisis, companies constantly need free cash flows to efficiently react to any uncertainty, thus ensuring solvency. Working capital requirement (WCR) has been recognized as a key factor for releasing tied up cash in companies. However, in literatures related to lot-sizing problem, WCR has only been studied in the single-level supply chain context. In this paper, we initially adopt WCR model for a multi-level case. A two-level (supplier–customer) model is established on the basis of the classic multi-level lot-sizing model integrated with WCR financing cost. To tackle this problem, we propose sequential and centralized approaches to solve the two-level case with a serial chain structure. The ZIO (Zero Inventory Ordering) property is further confirmed valid in both cases. This property allows us to establish a dynamic programming-based algorithm, which solves the problem in O(T ). Finally, numerical tests show differences in optimal plans obtained by both approaches and the influence of varying delays in payment on the WCR of both actors.

关键词: two-level ULS problem     lot-sizing     working capital requirement     ZIO property     infinite production capacity    

Elastoplastic frictional contact problem study on interference fits of compressor

ZHANG Hongwu, WU Changhua, LIAO Aihua

《能源前沿(英文)》 2008年 第2卷 第3期   页码 313-319 doi: 10.1007/s11708-008-0026-1

摘要: The FE parametric quadratic programming (PQP) method developed from the parametric variational principle (PVP) was used for the analysis of the stress distribution of the 3D elastoplastic frictional contact of an impeller-shaft sleeve-shaft. A locomotive-type turbocharger compressor with 24 blades under combined centrifugal and interference-fit loading was considered in the numerical analysis. The solution of elastoplastic frictional contact problems belongs to unspecified boundary problems where the interaction between two kinds of nonlinearities should occur. To save time in the numerical computation, a multi-substructure technique was adopted in the structural modeling. The effect of fit tolerance, wall thickness of the shaft sleeve, and rotational speed on the contact stress was discussed in detail in the numerical computation. To decrease the difficulty of the assembly process and ensure the safety of the working state, the amount of interference between the shaft sleeve and shaft by press-fitting should be controlled strictly to avoid the rapid increase of contact stress. The numerical results show that the algorithm has high accuracy and good convergence. The study can be referred to in deciding the proper fit tolerance and improving the design and manufacturing technology of compressor impellers.

关键词: computation     thickness     interference-fit     interference     unspecified    

标题 作者 时间 类型 操作

Identification of structural parameters and boundary conditions using a minimum number of measurement points

Ali KARIMPOUR, Salam RAHMATALLA

期刊论文

Robust cooperation of connected vehicle systems with eigenvalue-bounded interaction topologies in the

Keqiang LI, Feng GAO, Shengbo Eben LI, Yang ZHENG, Hongbo GAO

期刊论文

基于有序特征值矩阵的对称变量检测算法

Xiao-hua LI, Ji-zhong SHEN

期刊论文

Discussion on Problem-Based Engineering Management System

Qiao Xiang

期刊论文

Airline planning and scheduling: Models and solution methodologies

Lei ZHOU, Zhe LIANG, Chun-An CHOU, Wanpracha Art CHAOVALITWONGSE

期刊论文

A solution to stochastic unit commitment problem for a wind-thermal system coordination

B. SARAVANAN,Shreya MISHRA,Debrupa NAG

期刊论文

Solving unit commitment problem using a novel version of harmony search algorithm

Roozbeh MORSALI,Tohid JAFARI,Amirhossein GHODS,Mohammad KARIMI

期刊论文

Transient analysis of thermoelastic contact problem of disk brakes

Ali BELHOCINE, Mostefa BOUCHETARA

期刊论文

A solution to the unit commitment problem—a review

B. SARAVANAN, Siddharth DAS, Surbhi SIKRI, D. P. KOTHARI

期刊论文

Hydrocele of the canal of Nuck — an old problem revisited

null

期刊论文

A solution to unit commitment problem using invasive weed optimization algorithm

B. SARAVANAN, E. R. VASUDEVAN, D. P. KOTHARI

期刊论文

Method for solving the nonlinear inverse problem in gas face seal diagnosis based on surrogate models

期刊论文

A new technique for solving the multi-objective optimization problem using hybrid approach

Mimoun YOUNES,Khodja FOUAD,Belabbes BAGDAD

期刊论文

Two-level uncapacitated lot-sizing problem considering the financing cost of working capital requirement

Yuan BIAN, David LEMOINE, Thomas G. YEUNG, Nathalie BOSTEL

期刊论文

Elastoplastic frictional contact problem study on interference fits of compressor

ZHANG Hongwu, WU Changhua, LIAO Aihua

期刊论文