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Improved transmission design algorithms by utilizing variable-strength projections

JOURNAL OF MODERN OPTICS 2002年第11期49卷 1871-1892页

作者： Bühling, S Wyrowski, F LightTrans GmbH D-07745 Jena Germany Univ Jena D-07743 Jena Germany

The iterative Fourier transform algorithm (IFTA) is accepted as a powerful tool for the design of transmission functions under consideration of various kinds of design freedom. In this algorithm, projection operations are utilized for incorporating the existing design freedom. By introducing a variable projection-strength parameter, the projection operators can be relaxed or tensed up. We investigate the dependency of the convergence rate of the design algorithm from the projection strength parameter for various design problems at various states of iteration. From insights about this relation we derive strategies for modifying the projection strength during iteration, in order to increase the performance of the algorithm. We demonstrate that the convergence rate can be drastically increased for the design of phase-only transmissions and show that stagnations, occurring when using the IFTA for the design of quantized transmissions, can be overcome in many cases.

关键词： design problems design algorithm algorithms DEPENDENCE iterative methods transmission strength parameter Freedom Transmissions

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Improvements on removing nonoptimal support points in D-optimum design algorithms

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STATISTICS & PROBABILITY LETTERS 2007年第1期77卷 90-94页

作者： Harman, Radoslav Pronzato, Luc UNSA CNRS Lab 13S F-06903 Sophia Antipolis France Comenius Univ Fac Math Phys & Informat Dept Appl Math & Stat Bratislava 84248 Slovakia

We improve the inequality used in Pronzato [2003. Removing non-optimal support points in D-optimum design algorithms. Statist. Probab. Lett. 63, 223-228] to remove points from the design space during the search for a D-optimum design. Let be any design on a compact space X subset of R-m with a nonsingular information matrix, and let m + epsilon be the maximum of the variance function d(xi, x) over all x is an element of X. We prove that any support point x(*) of a D-optimum design on X must satisfy the inequality d(xi, x(*)) >= m(1 + epsilon/2 - root epsilon(4 + epsilon - 4/m)/2). We show that this new lower bound on d(xi, x(*)) is, in a sense, the best possible, and how it can be used to accelerate algorithms for D-optimum design. (c) 2006 Elsevier B.V. All rights reserved.

关键词： D-optimum design design algorithm support points

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Teaching and learning-based optimization algorithm for optimum design of steel buildings

Teaching and learning-based optimization algorithm for optim...

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2014 International Conference on Computing in Civil and Building Engineering

作者： Aydogdu, I. Akin, A. Department of Civil Engineering Akdeniz University P.O. Box 07058 Antalya Turkey Thomas and Betts Company MemphisTN United States

ISBN: (纸本)9780784413616

In this study, an algorithm is developed for the optimum design of the steel buildings. The optimum design problem is formulated according to LRFD-AISC. design constraints include;(1) displacement limitations;(2) inter-story drift restrictions of multi-story frames;(3) strength requirements for beams and beam-columns;and (4) geometric constraints. The teaching and learning-based optimization (TLBO) technique, inspired by the interaction and outcome of teacher and learners, is employed to determine its optimum solution. The design algorithm developed selects optimum W sections for beams and columns of three-dimensional steel frames so that aforementioned constraints are satisfied and the frame has the minimum weight. A large-scale steel building has been designed by TLBO algorithm developed in order to test performance of the algorithm. © ASCE 2014.

关键词： Optimal design Optimization algorithms Beams and girders Beam columns design algorithm algorithms Steels Minimum weight built structure Buildings Frame geometric constraint FRAMES Pedagogy Teaching

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A Fast Surrogate Model-Based algorithm Using Multilayer Perceptron Neural Networks for Microwave Circuit design

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algorithmS 2023年第7期16卷 324-324页

作者： Jamshidi, Mohammad (Behdad) Yahya, Salah I. I. Roshani, Saeed Chaudhary, Muhammad Akmal Ghadi, Yazeed Yasin Roshani, Sobhan Int Assoc Engineers IAENG Hong Kong 999077 Peoples R China Cihan Univ Erbil Dept Commun & Comp Engn Erbil 44001 Iraq Koya Univ Fac Engn Dept Software Engn Koya 46017 Iraq Islamic Azad Univ Dept Elect Engn Kermanshah Branch Kermanshah 67771 Iran Ajman Univ Coll Engn & Informat Technol Dept Elect & Comp Engn POB 346 Ajman U Arab Emirates Al Ain Univ Software Engn & Comp Sci Dept Al Ain PO POB 15551 Al Ain U Arab Emirates

This paper introduces a novel algorithm for designing a low-pass filter (LPF) and a microstrip Wilkinson power divider (WPD) using a neural network surrogate model. The proposed algorithm is applicable to various microwave devices, enhancing their performance and frequency response. Desirable output parameters can be achieved for the designed LPF and WPD by using the proposed algorithm. The proposed artificial neural network (ANN) surrogate model is employed to calculate the dimensions of the LPF and WPD, resulting in their efficient design. The LPF and WPD designs incorporate open stubs, stepped impedances, triangular-shaped resonators, and meandered lines to achieve optimal performance. The compact LPF occupies a size of only 0.15 & lambda;g x 0.081 & lambda;g, and exhibits a sharp response within the transmission band, with a sharpness parameter of approximately 185 dB/GHz. The designed WPD, operating at 1.5 GHz, exhibits outstanding harmonics suppression from 2 GHz to 20 GHz, with attenuation levels exceeding 20 dB. The WPD successfully suppresses 12 unwanted harmonics (2nd to 13th). The obtained results demonstrate that the proposed design algorithm effectively accomplishes the LPF and WPD designs, exhibiting desirable parameters such as operating frequency and high-frequency harmonics suppression. The WPD demonstrates a low insertion loss of 0.1 dB (S-21 = 0.1 dB), input and output return losses exceeding 30 dB (S-11 = -35 dB, S-22 = -30 dB), and an output ports isolation of more than 32 dB (S-23 = -32 dB), making it suitable for integration into modern communication systems.

关键词： design algorithm low-pass filter power divider neural network

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A novel approach to tube design via von Mises probability distribution

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ENGINEERING OPTIMIZATION 2024年第3期56卷 319-337页

作者： Oral, Atacan Subasi, Omer Ozturk, Caglar Lazoglu, Ismail Subay, Sehmuz Ali Koc Univ Mfg & Automat Res Ctr Istanbul Turkiye Acelik AS Compressor Plant Eskisehir Turkiye

Discharge tube is a critical component in a reciprocating compressor that carries the refrigerant. It also transmits vibrations from compressor body to housing, making the design of tube a complex engineering problem combining static, modal and flow behaviour. This study proposes a novel design algorithm for discharge tube, to decrease the dependency on the trial-and-error approach commonly used by manufacturers. The computational approach creates a tube that connects the inlet and outlet using von Mises probability distribution. The created geometries are checked for static and dynamic properties using FEA. The algorithm continues until a candidate design passes the imposed thresholds. The candidate designs perform similarly to benchmark in evaluated aspects, demonstrating promising results. The presented algorithm is successful in generating alternative tube designs from scratch and can accommodate varying requirements. The main novelty of this study is the development of a comprehensive decision algorithm that considers multiple engineering parameters simultaneously.

关键词： Discharge tube reciprocating compressor von Mises probability distribution finite element analysis design algorithm

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OPTIMAL-design OF AN UNCOUPLED 6 DEGREE OF FREEDOM DYNAMOMETER

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EXPERIMENTAL MECHANICS 1990年第1期30卷 40-48页

作者： QUINN, TP MOTE, CD 1. Department of Mechanical Engineering University of California 94720 Berkeley CA

A design analysis of a class of six degree of freedom strain-gage dynamometers which are virtually uncoupled in each force and moment component is presented. The method of design is detailed and an optimal design algorithm is implemented. The dynamometer is made of six or more T-sections with thin webs and flanges called shear panel elements (SPE). Complete stress and buckling analyses are carried out for the SPE, and experiments confirm the predictions of the analyses. The optimal design method is illustrated with several case studies. A dynamometer has been built and used in laboratory and field experiments.

关键词： Special purpose vehicles design analysis Optimal design design algorithm BUCKLING ANALYSIS Flanges six degrees of freedom solid phase epitaxial growth Dynamometer

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A Nonlinear Model Based Analysis and Accurate design of Ultracapacitor Stack for Energy Storage Systems

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IEEE TRANSACTIONS ON ENERGY CONVERSION 2022年第1期37卷 403-412页

作者： Roja, P. Venkatramanan, D. John, Vinod Indian Inst Sci Dept Elect Engn Bangalore 560012 Karnataka India Univ Minnesota Dept Elect & Comp Engn Minneapolis MN 55455 USA

Sizing of ultracapacitor (UC) stack is an essential requirement in the design of energy storage systems (ESS), which are widely deployed today in varied power conversion applications. Unlike a linear capacitor that displays constant capacitance characteristics over the operating voltage range, UCs exhibit considerable nonlinearity in the form of voltage-dependent capacitance and display notable variation in characteristics during operation. Analyzing the behavior of the overall UC bank that consists of several stacked nonlinear UC cells and evaluating its effective capacitance is therefore critical. In this paper, an exact-analysis framework is presented for characterizing the nonlinear behavior of the overall UC stack. Closed-form expressions for the UC stack's effective voltage-dependent capacitance, terminal voltage characteristics, and stored energy are derived as a function of unit cell nonlinear parameters and the number of series-parallel cells, using which the deviations in the UC stack behavior from the linear characteristics are analytically captured. It is shown, owing to the linear model of the UC employed in existing design methods, that the resultant stack will either be (a) over-sized and expensive, or (b) insufficient to meet the ride-through specifications in practice as the inherent nonlinearity is ignored. To address these limitations, an improved UC stack design method is proposed based on the nonlinear UC model, which not only optimizes the size of the UC stack, but also guarantees that the ESS specifications are accurately met. Experimental results on two UC stack hardware prototypes validate the accuracy of the proposed nonlinear analysis and the improved design method for ride-through applications.

关键词： Capacitance Power system stability Supercapacitors Discharges (electric) Capacitors Capacitance-voltage characteristics Analytical models Effective capacitance energy storage nonlinearity ultracapacitors voltage-dependency design algorithm

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A new algorithm for the design of Metal Oxide Varistor Surge Arresters

A new Algorithm for the Design of Metal Oxide Varistor Surge...

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IEEE International Conference on Environment and Electrical Engineering

作者： Nicolae Tarfulea Doru Vatau Florin Balcu Flaviu Mihai Frigura-Iliasa Petru Andea Amalia Corina Macarie Politehnica University Power Systems Department Timisoara Romania National Institute for Research and Development in Electrochemistry and Condensed Matter Timisoara Romania

ISBN: (纸本)9781509023219

Metal Oxide Varistors (also known as ZnO varistors) are built in many types of overvoltage protection equipment, being one of the most common solution for surge arresters. They have a higher non-linear dependence between voltage and current, and a relatively high heat adsorption capacity in case of normal overvoltage pulses. Their current is mostly activated by temperature, so overheating can cause a major damage. Researches could be carried out both for a new material as well as for technical solutions for a new design of this piece of equipment, by studying heat extraction and transfer inside a new varistor device. This paper propose a simple new device, used for low voltage applications, based on some supplementary brass masses added to the varistor, shaped as cylinders. They act like heat pumps at the beginning and as radiators at the end of the thermal process caused by a transitory overvoltage. A finite element model followed by some experimental measurements is also presented in order to confirm the new design, for permanent and transitory regimes.

关键词： Metal Oxide Varistors Low Voltage design algorithm

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Recent advances in design and performance optimization of pillow-plate heat exchangers: a critical review

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JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY 2023年第24期148卷 13679-13707页

作者： Sabourishirazi, Amirhossein Ghodrat, Maryam Liow, Jong-Leng Behnia, Masud Univ New South Wales Sch Engn & Informat Technol Canberra ACT 2600 Australia Stanford Univ CTR Stanford CA 94305 USA

Over the last two decades, extensive research has been dedicated to the crisis stemming from fossil fuel usage and its environmental repercussions. This pressing concern has garnered substantial attention due to its potential to disrupt ecological equilibrium and sustainability. Pursuing more efficient and sustainable solutions in the heat exchangers realm has catalyzed the development and optimization of innovative designs, notably pillow-plate heat exchangers (PPHEs). These next-generation heat exchangers offer improved compactness and reduced material requirements, effectively tackling mounting concerns related to energy and resource consumption. Integrating such advancements can mitigate the adverse environmental impact, fostering a greener and more sustainable future. This paper presents an exhaustive review of recent progress in PPHE design and optimization, emphasizing their potential for widespread application across diverse industries. These innovative heat exchangers feature sleek, pillow-like channels, offering exceptional heat transfer capabilities and minimal pressure drops. These attributes position PPHEs as a compelling and eco-conscious alternative to traditional heat exchangers. Nevertheless, the intricate geometries of PPHEs pose challenges for comprehensive research, and existing studies underscore the limited number and scope of their industrial applications. This manuscript thoroughly examines the critical facets of the literature related to various aspects of PPHEs, encompassing manufacturing processes, thermohydraulic channel characteristics, design algorithms, and cost assessments. By meticulously identifying and emphasizing critical research gaps, this work not only underscores the need for further investigation but also sets the stage for future studies to enhance the reliability and performance of PPHEs as a heat transfer equipment solution.

关键词： Pillow-plate heat exchanger Heat transfer Pressure drop Thermohydraulic performance design algorithm Cost estimation

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A comprehensive study on noise reduction methods of marine propellers and design procedures

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APPLIED ACOUSTICS 2019年 150卷 55-69页

作者： Ebrahimi, A. Razaghian, A. H. Seif, M. S. Zahedi, F. Nouri-Borujerdi, A. Sharif Univ Technol Ctr Excellence Hydrodynam & Dynam Marine Vehicles Tehran Iran

The noise generated by the propeller is one of the most important components of the vessels noise. Therefore, reducing this noise will significantly decrease the total noise of the vessel. Underwater noise of vessels has destructive effects on marine life. In addition, this noise affects the health and comfort of the crew and passengers of the ship. Moreover, high noise may cause warships to be detected easily. In this paper, first, common methods of noise reduction, including blade coating, modern propellers, propeller hub modification and ducted propellers are investigated. Then, relevant optimization methods are presented. Next, the effects of the geometric parameters like number of blades, propeller diameter, expanded area ratio, geometric pitch, rake and skew angles on the noise and the operational range of each parameter are studied. Finally, a new algorithm is suggested to optimally design a propeller considering hydrodynamics as well as acoustics concerns. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： Propeller noise Noise reduction Geometric parameters design algorithm

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