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AIAA Science and Technology Forum and Exposition (AIAA SciTech Forum)

作者： Liuzzi, Giampaolo Lucidi, Stefano Rinaldi, Francesco Pellegrini, Riccardo Serani, Andrea Diez, Matteo CNR CNR IASI Inst Syst Anal & Comp Sci Via Taurini 19 I-00185 Rome Italy Sapienza Univ Dept Comp Control & Management Engn Ruberti Via Ariosto 25 I-00185 Rome Italy Univ Padua Dept Math Via Trieste 63 I-35131 Padua Italy CNR CNR INM Inst Marine Engn Via Vallerano 139 I-00128 Rome Italy

ISBN: (数字)9781624106095

ISBN: (纸本)9781624106095

The paper presents a multi-fidelity coordinate-search derivative-free algorithm for non-smooth constrained optimization (MF-CS-DFN), in the context of simulation-based design optimization (SBDO). The objective of the work is the development of an optimization algorithm able to improve the convergence speed of the SBDO process. The proposed algorithm is of a line-search type and can handle objective function evaluations performed with variable accuracy. The algorithm automatically selects the accuracy of the objective function evaluation based an internal steplength parameter. The MF-CS-DFN algorithm starts the optimization with low accuracy and low-cost evaluations of the objective function, then the accuracy (and evaluation cost) is increased. The method is coupled with a potential flow solver whose accuracy is determined by the computational grid size. No surrogate models are used in the current study. The algorithm is applied to the hull-form optimization of a destroyer-type vessel in calm water using 14 hull-shape parameters as design variables. The optimization aims at the total resistance reduction. Seven refinements of the computational grid are used by the multi-fidelity optimizations. Four setups of the MF-CS-DFN algorithm are tested and compared with an optimization performed only on the finest grid. The results show that three of the tested setups achieve better performance than the high-fidelity optimization, converging to a lower resistance value with a reduced computational cost.

关键词： Surrogate Model Potential Flow Optimization algorithm search algorithm Reynolds Averaged Navier Stokes algorithms Convergence SONAR Shape Optimization Gaussian Process Hydrodynamics

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A search algorithm for constrained engineering optimization and tuning the gains of controllers

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EXPERT SYSTEMS WITH APPLICATIONS 2022年第0期206卷

作者： Nekoo, Saeed Rafee Acosta, Jose Angel Ollero, Anibal Univ Seville Escuela Tecn Super Ingn Dept Ingn Sistemas & Automat GRVC Robot Lab Seville Spain

In this work, the application of an optimization algorithm is investigated to optimize static and dynamic engineering problems. The methodology of the approach is to generate random solutions and find a zone for the initial answer and keep reducing the zones. The generated solution in each loop is independent of the previous answer that creates a powerful method. Simplicity as its main advantage and the interlaced use of intensification and diversification mechanisms-to refine the solution and avoid local minima/maxima-enable the users to apply that for a variety of problems. The proposed approach has been validated by several previously solved examples in structural optimization and scored good results. The method is also employed for dynamic problems in vibration and control. A modification has also been done on the method for high-dimensional test functions (functions with very large search domains) to converge fast to the global minimum or maximum;simulated for several well-known benchmarks successfully. For validation, a number of 9 static and 4 dynamic constrained optimization benchmark applications and 32 benchmark test functions are solved and provided, 45 in total. All the codes of this work are available as supplementary material in the online version of the paper on the journal website.

关键词： search algorithm Engineering optimization Static Dynamic Tuning control gain

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A Cluster and search Stacking algorithm (CSSA) for predicting the ultimate bearing capacity of an HSS column

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ACTA MECHANICA 2023年第4期234卷 1627-1648页

作者： He, Z. C. Peng, Y. Han, J. Zhou, E. L. Li, Bing Li, Eric Hunan Univ State Key Lab Adv Design & Mfg Vehicle Body Changsha 410082 Peoples R China Northwestern Polytech Univ Sch Aeronaut Xian 710072 Shaanxi Peoples R China Teesside Univ Sch Comp Engn & Digital Technol Middlesbrough England

High-strength steel (HSS) columns are widely used in industry and construction because of their outstanding properties. Predicting the ultimate bearing capacity of HSS columns is not an easy task due to many nonlinear factors such as geometry and material properties. In this paper, a Cluster and search Stacking algorithm (CSSA) model based on the cluster algorithm, search algorithm, and Stacking algorithm is proposed to predict the ultimate bearing capacity of HSS columns. Specifically, the clustering algorithm is used to cluster the base models, and the search algorithm is implemented to find the best combination of base models in the Stacking algorithm. Results show that the proposed CSSA model is more effective than base models optimized by the Bayesian Optimization algorithm. Furthermore, the Bland-Altman approach is utilized to examine the consistency of the CSSA model to validate its reliability. Finally, the Shapley additive explanation (SHAP) method is introduced to analyze and explain the ultimate bearing capacity predicted by the CSSA model.

关键词： Steel Bearing capacity search algorithm

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A gm/ID Methodology Based Data-Driven search algorithm for the Design of Multistage Multipath Feed-Forward-Compensated Amplifiers Targeting High Speed Continuous-Time ΣΔ-Modulators

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IEEE TRANSACTIONS ON COMPUTER-AIDED DESIGN OF INTEGRATED CIRCUITS AND SYSTEMS 2020年第12期39卷 4311-4324页

作者： Gebreyohannes, Fikre Tsigabu Porte, Jacky Louerat, Marie-Minerve Aboushady, Hassan Sorbonne Univ CNRS LIP6 F-75005 Paris France Univ Paris Saclay CEA IRFU Gif Sur Yvette France

This article presents a methodology for sizing transistors of a multistage, multipath capacitor-less feed-forward compensated operational amplifiers employed in advanced CMOS process implementation of continuous-time bandpass Sigma Delta-modulators. This article describes the methodology: on system level, dealing with the placement of poles and zeros;and on the circuit level, discussing issues related to biasing, frequency response and other important performance metrics of the basic diff-pair. algorithms are provided to simplify mathematical aspects of the work. The validity and the limitations of the proposed methodology are further discussed from the single-pole system used to model the individual amplification stages of the multistage amplifier. The worthiness of the proposed methodology in sizing the transistors of complex amplifier structures, such as the capacitor-less multistage, multipath feed-forward-compensated amplifiers is demonstrated using two design examples. A third-order amplifier with a dc gain of 52.6 dB and that reaches a unity-gain frequency of above 14 GHz while consuming only 5.6 mA from a 1-V supply;and a fourth-order amplifier with dc gain of 73.5 dB that achieves a 25.7-dB gain at 1 GHz while consuming 4.8 mW are designed in 28-nm CMOS FDSOI.

关键词： Continuous time feed-forward compensation gm/D-i methodology MATLAB script multipath multistage operational amplifier search algorithm sigma delta modulator

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An Optimal search algorithm of Integer Ambiguity in the Satellite Navigation Positioning

An Optimal Search Algorithm of Integer Ambiguity in the Sate...

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10th IEEE International Conference on Signal Processing, Communications and Computing (IEEE ICSPCC)

作者： Pei, Bingnan Jiang, Nie Pei, Tengda Quanzhou Univ Informat Engn Fujian Key Lab Modern Telecommun & Beidou Positio Quanzhou Peoples R China Dalian Univ Liaoning Engn Lab BDS High Precis Positioning Dalian Peoples R China

ISBN: (数字)9781728172026

ISBN: (纸本)9781728172019

In order to resolve the problem of too long search time caused by poor accuracy of the integer ambiguity floating-point solution, an improved search space algorithm was proposed. It was shown that the efficiency of a fixed integer ambiguity degree is greatly improved, with setting the initial search space and optimally updating of the upper and lower bounds that the algorithm works. Experimental simulations were given to show that the proposed algorithm is able to improve effectively search efficiency of the integer ambiguity, compared with the traditional LAMBDA algorithm and the VB algorithm,

关键词： satellite navigation positioning integer ambiguity search algorithm

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An Efficient Geometric search algorithm of Pandemic Boundary Detection

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algorithmS 2021年第8期14卷 244页

作者： Zhang, Zhanhao Huang, Qifan Columbia Univ Grad Sch Arts & Sci New York NY 10027 USA Univ Washington Dept Econ Seattle WA 98195 USA

We consider a scenario where the pandemic infection rate is inversely proportional to the power of the distance between the infected region and the non-infected region. In our study, we analyze the case where the exponent of the distance is 2, which is in accordance with Reilly's law of retail gravitation. One can test for infection but such tests are costly so one seeks to determine the region of infection while performing few tests. Our goal is to find a boundary region of minimal size that contains all infected areas. We discuss efficient algorithms and provide the asymptotic bound of the testing cost and simulation results for this problem.

关键词： boundary detection search algorithm public health transmission network artificial intelligence SEIR model

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A Proposed Harmony search algorithm for Honeyword Generation

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ADVANCES IN HUMAN-COMPUTER INTERACTION 2022年第0期2022卷

作者： Yasser, Yasser A. Sadiq, Ahmed T. AlHamdani, Wasim Univ Technol Iraq Comp Sci Dept Baghdad Iraq Univ Cumberlands Informat Technol Dept Williamsburg KY 40769 USA

The honeyword system is a password cracking detection technique that aims to improve the security of hashed passwords by making password cracking simpler to detect. Many honeywords (false passwords) accompany the sugarword (true password) to form the sweetwords (false and true passwords) for every user. If the attacker signs in using a honeyword, a silent alarm trigger shows that the honeyword system might be compromised. Many honeyword generation techniques are presented;each one has a flaw in the generating process, a lack of support for all honeyword characteristics, and a slew of honeyword problems. The harmony search algorithm (HSA), a metaheuristic intelligence algorithm inspired by music, is used in this article to offer a novel method for generating honeyword. The suggested honeyword generation technique will enhance the generating process, enhance honeyword characteristics, and address prior approaches' shortcomings. This paper will show several previous honeyword generation techniques, explain the suggested one, discuss the experimental findings, and compare the new honeyword generation method with the previous ones.

关键词： Password cracking Security search algorithm Hybrid algorithm

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Large dynamic range Shack-Hartmann wavefront measurement based on image segmentation and a neighbouring-region search algorithm

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OPTICS COMMUNICATIONS 2019年 450卷 190-201页

作者： Gao, Zeyu Li, Xinyang Ye, Hongwei Chinese Acad Sci Key Lab Adapt Opt Chengdu 610209 Sichuan Peoples R China Chinese Acad Sci Inst Opt & Elect Chengdu 610209 Sichuan Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China

The Shack-Hartmann wavefront sensor (SHWFS) has been used to measure wavefronts. However, the dynamic range and measurement accuracy limits the application of the SHWFS. A new centroid estimation algorithm based on image segmentation and related techniques to expand the dynamic range based on search strategy is presented in this paper. In this study, each spot is segmented from a spot array image and the centroid of each spot is calculated only in regions of segmented spots. To compute the slope between the spot centroid and the sub-aperture centre, the calculated centroids are assigned to their corresponding sub-apertures using a search method. The proposed method overcomes the limitations that the centroid must be calculated in its corresponding detection area and reduces the measurement errors caused by noise, expanding the dynamic range significantly without any change to the SHWFS setup as well as improving the measurement accuracy under strong noise. Moreover, the proposed method provides a unit linear coefficient response of centroid estimation. The dynamic range for the proposed method is evaluated by numerical simulations and experiments. Applications include measurement accuracy and linearity.

关键词： Shack-Hartmann wavefront sensor Dynamic range Wavefront measurement Centroiding methods Image segmentation search algorithm

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T*: a weighted double-heuristic search algorithm to find the shortest path

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INTERNATIONAL JOURNAL OF COMPUTING SCIENCE AND MATHEMATICS 2019年第1期10卷 58-70页

作者： Gharajeh, Mohammad Samadi Islamic Azad Univ Tabriz Branch Young Researchers & Elite Club Tabriz Iran

This paper proposes a weighted double-heuristic search algorithm to find the shortest path between two points. It can be used in numerous fields such as graph theory, game theory, and network. This algorithm, called T*, uses a weighted and heuristic function as f(x) = alpha x t(x) + beta x hl(x) + gamma x h2(x). It selects the path which minimises f(x) where x is a current node on the path, t(x) is cost of the path from start to x, h1(x) is a heuristic to estimate the cost from x to the straight line passing through start and target, and h2(x) is a heuristic to estimate cost of the cheapest path from x to target. Furthermore, alpha, beta and gamma indicate effective weights of each sub-function on f(x). T* algorithm is compared to the Greedy and A* algorithms in terms of hit rate and the number of processed nodes. Comparison results show that the proposed algorithm has a high efficiency compared to other algorithms.

关键词： shortest path search algorithm weighted strategy double-heuristic function graph theory

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Developing a Radiating L-shaped search algorithm for NASA Swarm Robots

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INTERNATIONAL JOURNAL OF ADVANCED COMPUTER SCIENCE AND APPLICATIONS 2020年第8期11卷 9-18页

作者： Tashtoush, Tariq Ahmed, Jalil Arce, Valeria Dominguez, Heriberto Estrada, Kevin Montes, William Paredez, Ashley Salce, Pedro Serna, Alexia Zarazua, Mireya Texas A&M Int Univ Sch Engn Laredo TX 78041 USA

This paper focuses on designing a search algorithm that the DustySWARM team used in the 2019 NASA Swarmathon competition. The developed search algorithm will be implemented and tested on multiple rovers, a.k.a. Swarmies or Swarm Robots. Swarmies are compact rovers, designed by NASA to mimic Ants behavior and perform an autonomous search for simulated Mars resources. This effort aimed to assist NASA's mission to explore the space and discover new resources on the Moon and Mars. NASA's going-on project has the goal to send robots that explore and collect resources for analysis before sending Astronauts, as the swarm option is safer and more affordable. All rovers must utilize the exact algorithm and collaborate and cooperate to find all available resources in their search path and retrieve them to the space station location. Additionally, swarmies will autonomously search while avoiding obstacles and mapping the surrounding environment for future missions. This algorithm allows a swarm of six robots to search an unknown area for simulated resources called AprilTags (cubes with QR codes). The code was developed using C/C++, GitHub, and Robotics Operation Systems (ROS) and tested by utilizing the Gazebo Simulation environment and by running physical trials on the swarmies. The team analyzed a few algorithms from previous years and other researchers then developed the Radiating L-Shape search (RLS) algorithm. This paper will summarize the algorithm design, code development, and trial results that were provided to the NASA Space Exploration Engineering team.

关键词： NASA Swarmathon competition swarm robotics search algorithm autonomous Robot Operating System (ROS) NASA space exploration simulation autonomous robot swarm collaborative robots autonomous behavior cooperative robots swarmies L-Shaped search GitHub

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