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MINLP Optimization of a Single-Storey Industrial Steel Building

STROJNISKI VESTNIK-JOURNAL OF MECHANICAL ENGINEERING 2008年第10期54卷 707-724页

作者： Zula, Tomaz Kravanja, Zdravko Kravanja, Stojan Univ Maribor Fac Civil Engn SLO-2000 Maribor Slovenia Univ Maribor Fac Chem & Chem Engn SLO-2000 Maribor Slovenia

The paper presents the topology and standard sizes optimization of a single-storey industrial steel building, made from standard hot rolled I sections. The structure consists of main portal frames, connected with purlins. The structural optimization is performed by the Mixed-Integer non-linear programming approach (MINLP). The MINLP performs a discrete topology and standard dimension optimization simultaneously with continuous parameters. Since the discrete/continuous optimization problem of the industrial building is non-convex and highly non-linear, the Modified Outer-Approximation/Equality-Relaxation (OA/ER) algorithm has been used for the optimization. Alongside the optimum structure mass, the optimum topology with the optimum number of portal frames and purlins as well as all standard cross-section sizes have been obtained. The paper includes the theoretical basis and a practical example with the results of the optimization. (C) 2008 Journal of Mechanical Engineering. All rights reserved.

关键词： industrial buildings topology optimization sizing optimization non-linear programming MINLP

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Managing product transitions with learning and congestion effects

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INTERNATIONAL JOURNAL OF PRODUCTION ECONOMICS 2021年 239卷 108190-108190页

作者： Manda, A. B. Uzsoy, Reha Intel Corp 5000 Chandler Blvd Chandler AZ 85286 USA North Carolina State Univ Dept Ind & Syst Engn Campus Box 7906 Raleigh NC 27695 USA

The introduction of a new product into an operating factory can have significant adverse impacts on the throughput and cycle time of all products produced in the factory, and thus needs to be managed carefully. In previous work we proposed a production planning model for new product introductions that captures the impact of additional variability caused by the new product and of learning as experience producing the new product is gained. This paper extends the earlier work by incorporating learning through deliberate experimentation using engineering lots and the impact of cycle time on line yield due to delays in detecting adverse events. We formulate a non-convex nonlinear optimization model to determine the mix of production and engineering lots to be processed, and obtain approximate solutions using a genetic algorithm. Numerical experiments with different scenarios show the importance of carefully managing the releases of production and engineering lots and of accelerating learning early in the time horizon through judicious use of engineering lots.

关键词： New product introduction Learning effects non-linear programming Genetic algorithms Semiconductor manufacturing

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Controlled Islanding Based on the Coherency of Generators and Minimum Electrical Distance

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IEEE ACCESS 2021年 9卷 146830-146840页

作者： Aghamohammadi, M. R. Mahdavizadeh, S. Fazel Shahid Beheshti Univ Elect Engn Dept Tehran *** Iran

Inter-area oscillations and cascading failures are the most serious threats to the security of the electric power system. Uncontrolled islanding will occur in the event of an unstable inter-area oscillation or a progressive cascading failure. The establishment of uncontrolled islands with a deficiency in load-generation balance is the main reason for system blackout. Controlled islanding has been proposed as a preventive strategy for reducing the risk of blackout in this regard. A new algorithm for applying the controlled islanding strategy is proposed in this paper, based on load coherency and nearest electrical distances between coherent groups of generators. Coherent generators as the main core for controlled islands are identified in this method, which is based on the correlation coefficients between generators and the DBSCAN clustering algorithm. The sub-networks are then created by applying mixed-integer linear programming to each coherent group. Once this is accomplished, non-linear programming is used to construct the stable sub-networks associated with islands that meet the requirements of load-generation balance, voltage limitations, and transmission limits. The proposed scheme is implemented on the small-scale IEEE 39-bus system and a large-scale realistic power system which is the Iran power grid. The results demonstrate that the proposed method is capable of being implemented in a real power system.

关键词： Intentional islanding generator coherency electrical distances DBSCAN algorithm Dijkstra algorithm non-linear programming

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Analyzing the price skimming strategy for new product pricing

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SCIENTIA IRANICA 2013年第6期20卷 2099-2108页

作者： Shavandi, H. Zare, A. G. Sharif Univ Technol Dept Ind Engn Tehran Iran

This article presents a new model for pricing a new product considering a skimming pricing strategy in the presence of competition. We consider two periods for price setting, including skimming and an economy period. The problem is to decide on skimming as well as economy price, in order to maximize total profit. The derived model is a non-linear programming model and we have analyzed the structure and properties of an optimal solution to develop a solution method. Analytical results, as well as managerial insights, are presented by mathematical and numerical analyses. (C) 2013 Sharif University of Technology. All rights reserved.

关键词： Skimming pricing non-linear programming New product development Pricing policy Competition

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Demand Response Model Development for Smart Households Using Time of Use Tariffs and Optimal Control-The Isle of Wight Energy Autonomous Community Case Study

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ENERGIES 2020年第3期13卷 541页

作者： Khanna, Sourav Becerra, Victor Allahham, Adib Giaouris, Damian Foster, Jamie M. Roberts, Keiron Hutchinson, David Fawcett, Jim Univ Portsmouth Sch Energy & Elect Engn Portsmouth PO1 3DJ Hants England Newcastle Univ Sch Engn Newcastle Upon Tyne NE1 7RU Tyne & Wear England Univ Portsmouth Sch Math & Phys Portsmouth PO1 2UP Hants England Univ Portsmouth Fac Technol Portsmouth PO1 3AH Hants England Isle Wight Council Cty Hall Newport PO30 1UD Isle Of Wight England

Residential variable energy price schemes can be made more effective with the use of a demand response (DR) strategy along with smart appliances. Using DR, the electricity bill of participating customers/households can be minimised, while pursuing other aims such as demand-shifting and maximising consumption of locally generated renewable-electricity. In this article, a two-stage optimization method is used to implement a price-based implicit DR scheme. The model considers a range of novel smart devices/technologies/schemes, connected to smart-meters and a local DR-Controller. A case study with various decarbonisation scenarios is used to analyse the effects of deploying the proposed DR-scheme in households located in the west area of the Isle of Wight (Southern United Kingdom). There are approximately 15,000 households, of which 3000 are not connected to the gas-network. Using a distribution network model along with a load flow software-tool, the secondary voltages and apparent-power through transformers at the relevant substations are computed. The results show that in summer, participating households could export up to 6.4 MW of power, which is 10% of installed large-scale photovoltaics (PV) capacity on the island. Average carbon dioxide equivalent (CO(2)e) reductions of 7.1 ktons/annum and a reduction in combined energy/transport fuel-bills of 60%/annum could be achieved by participating households.

关键词： demand response electric vehicle solar photovoltaics battery optimisation non-linear programming sustainability

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Quasi-static path optimization for industrial robots with dress packs

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ROBOTICS AND COMPUTER-INTEGRATED MANUFACTURING 2021年 68卷 102055-102055页

作者： Hermansson, T. Carlson, J. S. Linn, J. Kressin, J. Fraunhofer Chalmers Ctr Chalmers Sci Pk S-41288 Gothenburg Sweden Fraunhofer ITWM Fraunhofer Pl 1 D-67663 Kaiserslautern Germany

Problems with robot dress packs are a major reason for on-line adjustments of robot programs and down-time in robot stations. It is therefore of high value if the physical behaviour of the dress packs can be considered with simulation methods already during the off-line programming process for a robot station. This paper presents a method for quasi-static path optimization for an industrial robot with respect to its deformable dress pack. Given an initial collision-free path generated by an automatic path planner, the via point configurations of the path are optimized with respect to the performance aspects of the dress pack. The method is derived from a general framework for parameter optimization of a mechanical system subject to quasi-static motions and deformations. The optimal parameter values are obtained from numerical solutions to a non-linear programming problem in which the static equilibrium equations of the system hold at discrete times. Due to the large-scale nature of this problem, a dress pack is modelled as a discrete Cosserat rod, which is the preferred choice for modeling large spatial deformations of a slender flexible structure with coarse discretization. The method is applied to an industrial robot moving in-between stud welding operations in a stud welding station. The optimized path reduces the stress in the dress pack and keeps the dressed robot from the surrounding geometry with a prescribed safety clearance during the entire robot motion.

关键词： Robot path optimization Parameter optimization Robot dress packs Cosserat rods Quasi-static simulation non-linear programming

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Design optimization of multi-resonant piezoelectric energy harvesters

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MICROELECTRONICS RELIABILITY 2021年 120卷 114114-114114页

作者： Hu, Siyang Bouhedma, Sofiane Schutz, Arwed Stindt, Simon Hohlfeld, Dennis Bechtold, Tamara Jade Univ Appl Sci Dept Engn Friedrich Paffrath Str 101 D-26389 Wilhelmshaven Germany Univ Rostock Inst Elect Appliances & Circuits Albert Einstein Str 2 D-18059 Rostock Germany

In this work, we perform a two-stage design optimization of the folded beam multi-resonant piezoelectric energy harvester. The optimization routine involves a global pre-optimization using evolutionary algorithm and a subsequent local optimization by classical non-linear programming. Optimization resulted in designs, which shows promising characteristics in simulation. For the validation of simulation results, we fabricated the optimal designs and performed experimental characterization. Simultaneously, we developed a comparable array of single beam piezoelectric harvesters, which we compared with the optimized folded beam designs. Both new designs significantly outperform the initial one in terms of frequency spacing. Furthermore, the experimental data demonstrate that the optimized folded beam designs generate considerably higher maximum voltage compared to the proposed array-structured designs.

关键词： Global optimization Evolutionary algorithm non-linear programming MEMS Piezoelectric energy harvester

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Packing circles in the smallest circle: an adaptive hybrid algorithm

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JOURNAL OF THE OPERATIONAL RESEARCH SOCIETY 2011年第11期62卷 1917-1930页

作者： Al-Mudahka, I. Hifi, M. M'Hallah, R. UPJV Amiens MIS F-8000 Amiens France Kuwait Univ Safat 13060 Kuwait

The circular packing problem (CPP) consists of packing n circles C-i of known radii r(i), i is an element of N = {1, ..., n}, into the smallest containing circle C. The objective is to determine the coordinates (x(i), y(i)) of the centre of C-i, i is an element of N, as well as the radius r and centre (x,y) of C. CPP, which is a variant of the two-dimensional open-dimension problem, is NP hard. This paper presents an adaptive algorithm that incorporates nested partitioning within a tabu search and applies some diversification strategies to obtain a (near) global optimum. The tabu search is to identify the n circles' ordering, whereas the nested partitioning is to determine the n circles' positions that yield the smallest r. The computational results show the efficiency of the proposed algorithm. Journal of the Operational Research Society (2011) 62, 1917-1930. doi:10.1057/jors.2010.157 Published online 24 November 2010

关键词： heuristics tabu search non-linear programming circular packing nested partitioning

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Optimal number and sizes of the doses in fractionated radiotherapy according to the LQ model

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MATHEMATICAL MEDICINE AND BIOLOGY-A JOURNAL OF THE IMA 2019年第1期36卷 1-53页

作者： Bruni, C. Conte, F. Papa, F. Sinisgalli, C. CNR Ist Anal Sistemi & Informat A Ruberti Via Taurini 19 I-00185 Rome Italy

We address a non-linear programming problem to find the optimal scheme of dose fractionation in cancer radiotherapy. Using the LQ model to represent the response to radiation of tumour and normal tissues, we formulate a constrained non-linear optimization problem in terms of the variables number and sizes of the dose fractions. Quadratic constraints are imposed to guarantee that the damages to the early and late responding normal tissues do not exceed assigned tolerable levels. linear constraints are set to limit the size of the daily doses. The optimal solutions are found in two steps: i) analytical determination of the optimal sizes of the fractional doses for a fixed, but arbitrary number of fractions n;ii) numerical simulation of a sequence of the previous optima for n increasing, and for specific tumour classes. We prove the existence of a finite upper bound for the optimal number of fractions. So, the optimum with respect to n is found by means of a finite number of comparisons amongst the optimal values of the objective function at the first step. In the numerical simulations, the radiosensitivity and repopulation parameters of the normal tissue are fixed, while we investigate the behaviour of the optimal solution for wide variations of the tumour parameters, relating our optima to real clinical protocols. We recognize that the optimality of hypo or equi-fractionated treatment schemes depends on the value of the tumour radiosensitivity ratio compared to the normal tissue radiosensitivity. Fast growing, radioresistant tumours may require particularly short optimal treatments.

关键词： non-linear programming linear-quadratic LQ model cancer radiotherapy

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Funções penalidade para o tratamento das variáveis discretas do problema de fluxo de potência ótimo reativo

Funções penalidade para o tratamento das variáveis discre...

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作者： Silva, Daisy Paes Universidade Estadual Paulista

O problema de Fluxo de Potência Ótimo (FPO) é considerado um importante problema da Engenharia Elétrica desde a década de 1960. A partir de então, muitos trabalhos foram publicados com diferentes formulações e abordagens para a resolução deste problema. Muitas destas abordagens desconsiderava a natureza discreta das variáveis de controle e consideram todas as variáveis do problema como contínuas. Estas formulações são aproximações do problema de FPO, pois, algumas variáveis podem somente ser ajustadas por passos discretos, conforme a realidade do sistema. No problema de Fluxo de Potência Ótimo Reativo (FPOR), caso particular do problema de FPO, as variáveis relacionadas à potência ativa são fixadas e a otimização somente considera as variáveis relacionadas à potência reativa. O problema de FPOR pode ser modelado matematicamente como um problema de programação não-linear com variáveis discretas e contínuas. Neste trabalho, propõem-se das abordagens para resolução do problema FPOR que consideram a natureza discreta das variáveis do problema. Nas abordagens propostas são utilizadas funções penalidade associadas a um método de pontos interiores, combinando as vantagens de ambos para a resolução do problema de FPOR. Desenvolvem-se funções penalidade polinomiais para tratar as variáveis de controle discretas do problema, taps dos transformadores e bancos de capacitores e de reatores shunt, obtendo-se uma sequência de problemas contínuos, diferenciáveis e penalizados, que são resolvidos pelo método de pontos interiores implementado no solver gratuito IPOPT. As soluções de tais problemas convergem para a solução do problema original. Os testes numéricos foram realizados com os sistemas elétricos IEEE 14, 30, 118 e 300 barras para verificar a eficiência das abordagens *** Optimal Power Flow Problem (OPF) is considered an important problem of the electrical engineering since the 1960s. From that moment, many papers were published with different formulations and appr

关键词： Fluxo de potência ótimo reativo Programação não-linear Variáveis discretas Funções penalidade polinomiais Reactive optimal power flow non-linear programming Discrete Variables Polynomial penalty functions Dissertação de mestrado

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