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Identification of material parameters for thin sheets from single biaxial tensile test using a sequential inverse identification strategy

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INTERNATIONAL JOURNAL OF MATERIAL FORMING 2016年第4期9卷 547-571页

作者： Prates, P. A. Oliveira, M. C. Fernandes, J. V. Univ Coimbra CEMUC Dept Mech Engn Rua Luis Reis Santos P-3030788 Coimbra Portugal

An inverse analysis methodology to simultaneously identify the parameters of various anisotropic yield criteria together with isotropic work-hardening models of metal sheets is outlined. This identification makes use of results of the cruciform biaxial test, i.e., the evolution of the force during the test, for the two axes of the sample, and the major and minor strain distributions along both axes, at a given moment during the test. Based on a study of the sensitivity of the constitutive parameters to the biaxial tensile test results, the inverse identification consists on a procedure that sequentially minimises the gap between experimental and numerical results. Each step of the sequence uses a distinct cost function according to the type of results to be minimised, using a gradient-based optimisation algorithm, the Levenberg-Marquardt method. The inverse methodology allows for the identification of constitutive parameters of complex constitutive models. This sequential identification strategy is compared to a strategy based on a single cost function, involving all parameters and type of results, which has lower performance.

关键词： Constitutive parameter identification Biaxial tensile test Inverse analysis optimisation algorithm Finite element method

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Memory limited algorithms for optimal task scheduling on parallel systems

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JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING 2016年 92卷 35-49页

作者： Venugopalan, Sarad Sinnen, Oliver Univ Auckland Dept Elect & Comp Engn Auckland 1 New Zealand

To hilly benefit from a multi-processor system, tasks need to be scheduled optimally. Given that the task scheduling problem with communication delays, P vertical bar prec, c(ij)vertical bar C-max, is a well known strong NP-hard problem, exhaustive approaches are necessary. The previously proposed A* based algorithm retains its entire state space in memory and often runs out of memory before it finds an optimal solution. This paper investigates and proposes two memory limited optimal scheduling algorithms: Iterative Deepening A* (IDA*) and Depth-First Branch and Bound A* (BBA*). When finding a guaranteed near optimal schedule length is sufficient, the proposed algorithms can be combined, reporting the gap while they run. Problem specific pruning techniques, which are crucial for good performance, are studied for the two proposed algorithms. Extensive experiments are conducted to evaluate and compare the proposed algorithms with previous optimal algorithms. (C) 2016 Elsevier Inc. All rights reserved.

关键词： Optimal task scheduling A Iterative Deepening A Depth-First Branch and Bound A Parallel systems Memory limited Iterative deepening State space pruning optimisation algorithm

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Risk-constrained multi-level framework for coordination of generation and transmission expansion planning in liberalised environments - part II: method and case studies

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IET GENERATION TRANSMISSION & DISTRIBUTION 2016年第13期10卷 3191-3200页

作者： Shivaie, Mojtaba Ameli, Mohammad T. Shahid Beheshti Univ Dept Elect Engn AC Tehran Iran

This paper presents a new hybrid method for solving the proposed multi-level optimisation problem, as described in Part I. The hybrid method employs a novel two-stage multi-dimensional melody search algorithm (MSA) with an innovative alternative improvisation procedure (AIP). This hybrid method handles the different levels of the proposed multi-level framework. The two-stage multi-dimensional MSA is a recently developed optimisation algorithm, which is derived from the harmony search algorithm (HSA). Unlike the HSA, the MSA uses different player memories and a group improvisation procedure for finding the best substitution of pitches within a melody. These two features can enhance the performance of the MSA in comparison with the HSA. In addition, to improve the efficiency of the proposed MSA, an innovative improvisation scheme based on the AIP is used for generating new melodies. The proposed methodology has been applied on the 46-bus south Brazilian electric power grid and the IEEE 118-bus test system under two different scenarios in order to demonstrate the feasibility and capabilities of the newly developed framework. The obtained results from case studies validate sufficiency and profitableness of the offered multi-level framework.

关键词： power generation planning power transmission planning risk management optimisation power grids search problems risk-constrained multilevel framework generation expansion planning coordination transmission expansion planning coordination multilevel optimisation problem novel two-stage multidimensional melody search algorithm two-stage multidimensional MSA alternative improvisation procedure AIP optimisation algorithm harmony search algorithm HSA player memories group improvisation procedure 46-bus south Brazilian electric power grid IEEE 118-bus test system

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Cold ironing and onshore generation for airborne emission reductions in ports

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART M-JOURNAL OF ENGINEERING FOR THE MARITIME ENVIRONMENT 2016年第1期230卷 67-82页

作者： Sciberras, Edward A. Zahawi, Bashar Atkinson, David J. Juando, Aitor Sarasquete, Adrian Newcastle Univ Sch Elect & Elect Engn Newcastle Upon Tyne NE1 7RU Tyne & Wear England Vicus Desarrollos Tecnol SL Vigo Spain

Cold ironing (or onshore power supply) addresses airborne emissions while ships are berthed in port. By providing the electrical power demands from shoreside electricity, the onboard auxiliary generators can be switched off for a locally emission-free solution. The net emissions will of course be dependent on the actual shoreside electricity mix, but reductions can be realised in most cases. This study looks at the various electrical configurations available for cold ironing of berthed vessels. Shoreside generation using liquefied natural gas as an alternative fuel is also considered as a complement to cold ironing. This provides the possibility of hybridised solutions combining power supply from the grid or from clean, onsite generators. Using real data from an operational European port, the various cold ironing configurations are modelled and optimal trade-off solutions were identified. This is achieved by considering the reduction in emissions and minimisation of component costs as a multi-objective non-linear optimisation problem. The results show that CO2 emissions can be reduced by up to 40% by using cold ironing, while the use of liquefied natural gas shore generation can reduce the sulphur and particulate emissions in port to extremely low levels.

关键词： Cold ironing onshore power supply air pollution optimisation algorithm shoreside power liquefied natural gas generation

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Delay management and energy consumption minimisation on a single-track railway

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IET INTELLIGENT TRANSPORT SYSTEMS 2016年第1期10卷 50-57页

作者： Umiliacchi, Silvia Nicholson, Gemma Zhao, Ning Schmid, Felix Roberts, Clive Univ Birmingham Sch Elect Elect & Syst Engn Birmingham W Midlands England

To become more competitive, railways are developing methods and technologies that enable cost reduction, higher capacity, better punctuality and greater sustainability. The authors of this study address the last two objectives and propose a method that can be used to minimise the impact of a single delay on the system by reducing both the deviation from timetabled arrival at timing points and the energy consumed by trains. The technique uses a combined macro- and microscopic level approach in an optimisation algorithm to calculate the maximum speed a train should travel at on different sections of its route, so that the train meets time constraints and saves energy. The algorithm interacts with the traffic management system to obtain the applicable time constraints. The initial results from a case study based on a single-track railway line show that applying this method to a freight train that needs to pass a late running passenger train at a loop and to arrive on time at its last station allows a 9% reduction in energy use by comparison with a situation where the freight train trajectory is not adjusted as a function of the actual traffic conditions.

关键词： railways minimisation rail traffic control freight handling delay management energy consumption minimisation single-track railway cost reduction train capacity punctuality sustainability deviation reduction timetabled arrival timing points energy consumption macroscopic level approach microscopic level approach optimisation algorithm maximum speed time constraints energy saving traffic management system time constraints single-track railway line freight train late running passenger train time station freight train trajectory traffic conditions

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Energy management strategy for a fuel cell hybrid vehicle based on maximum efficiency and maximum power identification

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IET ELECTRICAL SYSTEMS IN TRANSPORTATION 2016年第4期6卷 261-268页

作者： Ettihir, Khalid Boulon, Loic Agbossou, Kodjo Univ Quebec Trois Rivieres Hydrogen Res Inst POB 500 Trois Rivieres PQ G9A 5H7 Canada

This paper addresses the energy management strategy (EMS) for a fuel cell hybrid electric vehicle (FC-HEV). The fuel cell system (FCS) is a multi-physics system, and consequently, its energetic performances depend on the degradation and on the operating conditions. The maximum power (MP) and the maximum efficiency (ME) points of the FCS are unique but they move with operating condition variations. Thus, developing an extremum seeking process (ESP) for both MP and ME tracking is a challenging task. In the ESP, models are identified online by using an adaptive recursive least square (ARLS) method to seek a variation in the FCS performances. Then an optimisation algorithm is used on the updated model to find the MP and the ME points. The ESP is incorporated into a hysteresis power splitting control (HPSC). A MP mode or a ME mode can be set based on the energy storage level (battery pack). The effectiveness of the proposed MP-and ME-ESP EMS is demonstrated by conducting experimental studies on two FCSs with different levels of degradation. It was demonstrated that the classical EMS based on maps are not valid when the operating parameters vary because of the level of degradation change.

关键词： energy management systems fuel cell vehicles hybrid electric vehicles least squares approximations recursive estimation adaptive estimation optimisation energy management strategy maximum power identification FC-HEV fuel cell hybrid electric vehicle fuel cell system FCS multiphysics system maximum efficiency point extremum seeking process ESP ME tracking MP tracking adaptive recursive least square method optimisation algorithm hysteresis power splitting control HPSC energy storage level

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Parametric Modelling of Twin Rotor System using Chaotic Fractal Search algorithm 7

Parametric Modelling of Twin Rotor System using Chaotic Frac...

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7th IEEE Control and System Graduate Research Colloquium (ICSGRC)

作者： Rahman, Tuan A. Z. Univ Putra Malaysia Fac Engn Dept Mech & Mfg Engn Serdang 43400 Selangor Malaysia

ISBN: (纸本)9781509011759

Nature-inspired metaheuristic algorithms have emerged as an active research field in the past two decades due to their advantages such as simplicity in structure, flexibility in implementation and local optima avoidance. One of the latest optimisation algorithms is Stochastic Fractal Search (SFS) algorithm. This paper presents the application of enhanced Fractal Search algorithms with chaos in parametric modelling of a twin rotor system (TRS). Firstly, the improved Fractal Search algorithms were evaluated using 4 well-known classical benchmark functions with different dimension levels. Then, the modified Fractal Search algorithms are employed to optimise the parameters for an ARX model of twin rotor system in hovering mode. The final results found that Chaotic Fractal Search (CFS) algorithm with Gauss/Mouse map shows superiority over other enhanced SFS algorithms when applied both in Diffusion Process and Updating Process.

关键词： chaotic fractal search optimisation algorithm chaos maps twin rotor system

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Delay management and energy consumption minimisation on a single-track railway

Delay management and energy consumption minimisation on a si...

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3rd RRUKA Annual Conference

作者： Umiliacchi, Silvia Nicholson, Gemma Zhao, Ning Schmid, Felix Roberts, Clive Univ Birmingham Sch Elect Elect & Syst Engn Birmingham W Midlands England

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Application-tailored optimisation of photonic crystal waveguides

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JOURNAL OF OPTICS 2016年第11期18卷 115005-115005页

作者： Billings, Sean Schulz, Sebastian A. Upham, Jeremy Boyd, Robert W. Univ Ottawa Sch Elect Engn & Comp Sci Ottawa ON Canada Univ Ottawa Dept Phys Ottawa ON Canada Univ Rochester Inst Opt Rochester NY 14627 USA

Photonic crystal. (PhC) waveguides are used for a wide range of applications with diverse performance metrics. A waveguide optimised for one application may not be suitable for others and no one-size-fits-all solution exists. Therefore each application requires a specialised waveguide design, a computationally and time intensive process. Here, we present a hybrid, multi-objective optimisation routine for PhC waveguides, to efficiently guide the device design. The algorithm can be configured to optimise for a wide range of performance metrics and applications. We demonstrate optimisations for three different applications: slow light performance, propagation loss due to fabrication disorder and delay line applications. For each optimisation target, our routine quickly finds practical waveguide designs (<48 h, on a laptop computer) that match or exceed the performance of state-of-the-art devices designed by the community over the last 10 years. This is also the first time that scattering loss from fabrication disorder has been incorporated into an optimisation algorithm, ensuring realistic predictions of a PhC waveguide design's practical performance.

关键词： photonic crystals optimisation algorithm design

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Novel adaptive bacterial foraging algorithms for global optimisation with application to modelling of a TRS

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EXPERT SYSTEMS WITH APPLICATIONS 2015年第3期42卷 1513-1530页

作者： Nasir, A. N. K. Tokhi, M. O. Ghani, N. M. A. Univ Sheffield Dept Automat Control & Syst Engn Sheffield S10 2TN S Yorkshire England Univ Malaysia Pahang Dept Elect & Elect Pekan Pahang 26600 Malaysia

In this paper, adaptive bacterial foraging algorithms and their application to solve real world problems is presented. The constant step size in the original bacterial foraging algorithm causes oscillation in the convergence graph where bacteria are not able to reach the optimum location with large step size, hence reducing the accuracy of the final solution. On the contrary, if a small step size is used, an optimal solution may be achieved, but at a very slow pace, thus affecting the speed of convergence. As an alternative, adaptive schemes of chemotactic step size based on individual bacterium fitness value, index of iteration and index of chemotaxis are introduced to overcome such problems. The proposed strategy enables bacteria to move with a large step size at the early stage of the search operation or during the exploration phase. At a later stage of the search operation and exploitation stage where the bacteria move towards an optimum point, the bacteria step size is kept reducing until they reach their full life cycle. The performances of the proposed algorithms are tested with various dimensions, fitness landscapes and complexities of several standard benchmark functions and they are statistically evaluated and compared with the original algorithm. Moreover, based on the statistical result, non-parametric Friedman and Wilcoxon signed rank tests and parametric t-test are performed to check the significant difference in the performance of the algorithms. The algorithms are further employed to predict a neural network dynamic model of a laboratory-scale helicopter in the hovering mode. The results show that the proposed algorithms outperform the predecessor algorithm in terms of fitness accuracy and convergence speed. (C) 2014 Elsevier Ltd. All rights reserved.

关键词： Adaptive bacterial foraging optimisation algorithm Nonparametric modelling Twin rotor system

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