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ASME 2024 43rd International Conference on Ocean, Offshore and Arctic Engineering, OMAE 2024

作者： Tu, Yu Zhang, Kai Chen, Yaoran Han, Zhaolong Cao, Yong Zhou, Dai Shanghai Jiao Tong University Shanghai China Shanghai University Shanghai China

ISBN: (纸本)9780791887851

In wind farms, wake effects among turbines hinder optimal power generation, making collective yaw control crucial for efficiency. The accurate calculation of power generation for large-scale wind farm is time consuming and computationally expensive. To address this challenge, Surrogate-Based Optimization (SBO) emerges as an effective tool in the yaw optimization. In the design of experiment, wake effects are simulated by Gauss-Curl Hybrid (GCH) model in FLORIS. Based on the limited dataset, SBO utilizes surrogate models to approximate the relationship between yaw angles and total power in the entire design space, enabling a more efficient approach to yaw optimization. The selection of optimization algorithms within the SBO framework becomes pivotal, with the recognition that gradient-free methods excel in scenarios with multiple local minima, while gradient-based methods offer advantages in high-dimensional problems inherent in large-scale wind farms. This paper compares three optimization algorithms—Sequential Least Squares Quadratic Programming (SLSQP), Differential Evolution (DE), and Particle Swarm Optimization (PSO)—in the context of wind farm yaw optimization. Three yaw control case studies are presented, offering a comprehensive comparison of the strengths and limitations of the optimization algorithms. Results show that the gradient-free methods, balancing computational cost and accuracy, stand out as the preferred choice for wind farm yaw optimization. Despite the low-fidelity engineering wake model used in the current study, the SBO framework is also compatible with the higher-fidelity wind turbine models. This capability lays the foundation for optimizing yaw control under more realistic conditions. Copyright © 2024 by ASME.

关键词： Wakes Yaw Optimization optimized algorithm wake model Wind farms yaw control surrogate-based optimization (SBO)

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Analytical model for flexural-torsional coupling behavior of prestressed corrugated steel-concrete composite girders

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ENGINEERING STRUCTURES 2024年 319卷

作者： Zhang, Hao Zhao, Qiu Chen, Yiyan Fang, Xiaojun Yang, Zhaohui Yang, Xiaoqiang Fuzhou Univ Coll Civil Engn Fuzhou 350108 Peoples R China Hong Kong Polytech Univ Dept Civil & Environm Engn Hung Hom Kowloon Hong Kong Peoples R China Guangzhou Univ Earthquake Engn Res & Test Ctr Prov Key Lab Earthquake Engn & Appl Technol Guangzhou Peoples R China Washington State Univ Sch Mech & Mat Engn Pullman WA USA

Prestressed corrugated steel-concrete (PCSC) composite girders are often subjected to combined bending and torsion in practice, but the existing theoretical models have mainly focused on pure torsional behavior. Thus, this paper proposed a modified combined action softened truss model (MCA-STM) to predict the flexural-torsional coupling behavior and failure modes of PCSC composite girders. The equivalent loading and nonlinear equations were modified, and the convergence criteria of flexural and torsional failure were established, considering the structural characteristics of PCSC composite girders. A new optimized algorithm was employed to solve the MCA-STM, providing a more efficient and numerically stable solution procedure. A 3D finite element analysis (FEA) model of the PCSC composite girder was established, which was verified by comparing the available test results. A parametric study was carried out based on the verified FEA model to get more datasets with various parameters, and the results were compared to the proposed analytical model. The curves obtained by the FEA and MCA-STM are in good agreement, indicating that the proposed analytical model can predict the full flexuraltorsional coupling behavior and failure modes of the PCSC composite girders.

关键词： Corrugated steel-concrete composite girders Combined action softened truss model Flexural-torsional coupling behavior Failure modes optimized algorithm

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A Novel Optimization algorithm for Calibrating Pollutant Degradation Coefficient in Deep Tunnel Based on Storm Water Management Model

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Journal of Geoscience and Environment Protection 2024年第12期12卷 207-217页

作者： Kaiyuan Zheng Ying Zhang Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen China Kyoto University-Tsinghua University Cooperative Research and Education Center for Environmental Technology Kyoto Japan State Environmental Protection Key Laboratory of Microorganism Application and Risk Control School of Environment Tsinghua University Beijing China

Aiming at working out more accurate pollutant degradation coefficient of the deep tunnel system, this work puts forward a novel optimized algorithm to calibrate such coefficient and compare it with the ordinary fitting method. This algorithm incorporates the outlier filtration mechanism and the gradient descent mechanism to improve its performance, and the calibration result is substituted into storm water management model (SWMM) source codes to validate its effectiveness between simulated and observed data. COD, NH3-N, TN and TP are chosen as pollutant indicators of the observed data, and the RMSE, MSE and ME are selected as indicators to present the efficiency. The results show that the outlier filtration mechanism obtains better performance than fitting method, with the gradient descent mechanism nearly reduces 92.42% of the iterative amounts and improves 55 times of the computation efficiency than the ordinary iterative method, such algorithm is expected to function better with substantial observed data.

关键词： SWMM Pollutant Degradation Coefficient Deep Tunnel System optimized algorithm

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Micro Light Flow Controller on a Programmable Waveguide Engine

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MICROMACHINES 2022年第11期13卷 1990-1990页

作者： Chen, Tao Dang, Zhangqi Deng, Zeyu Ding, Zhenming Zhang, Ziyang Zhejiang Univ Coll Informat Sci & Elect Engn Hangzhou 310027 Peoples R China Westlake Univ Sch Engn Lab Photon Integrat Hangzhou 310024 Peoples R China

A light flow controller that can regulate the three-port optical power in both lossless and lossy modus is realized on a programmable multimode waveguide engine. The microheaters on the waveguide chip mimic the tunable "pixels" that can continuously adjust the local refractive index. Compared to the conventional method where the tuning takes place only on single-mode waveguides, the proposed structure is more compact and requires less electrodes. The local index changes in a multimode waveguide can alter the mode numbers, field distribution, and propagation constants of each individual mode, all of which can alter the multimode interference pattern significantly. However, these changes are mostly complex and not governed by analytical equations as in the single-mode case. Though numerical simulations can be performed to predict the device response, the thermal and electromagnetic computing involved is mostly time-consuming. Here, a multi-level search program is developed based on experiments only. It can reach a target output in real time by adjusting the microheaters collectively and iteratively. It can also jump over local optima and further improve the cost function on a global level. With only a simple waveguide structure and four microheaters, light can be routed freely into any of the three output ports with arbitrary power ratios, with and without extra attenuation. This work may trigger new ideas in developing compact and efficient photonic integrated devices for applications in optical communication and computing.

关键词： programmable photonic integrated circuits arbitrary power splitter optimized algorithm thermo-optic effects

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Optimization algorithm on salient detection

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MULTIMEDIA TOOLS AND APPLICATIONS 2020年第9-10期79卷 6437-6445页

作者： Li, Ning Bi, Hongbo Guan, Huaping Li, Yulong Northeast Petr Univ Sch Elect & Informat Engn Daqing 163000 Peoples R China Sch Fujian Normal Univ Sch Publ Adm Fuzhou 350117 Fujian Peoples R China XJ Elect CO LTD Xuchang 461000 Peoples R China

Current studies on salient detection have combined salient cues, such as contrast, prior information, and object edges, which work by segmenting the foreground from the background. However, existing models mostly lose tiny salient regions in scenes and fail to detect all salient regions. In this paper, we propose an optimization algorithm on salient detection based on line sketch. First, we generate the line sketches of images, which include all edges of the salient objects. Second, the detected line sketches are blended into the original images in soft light mode. Then, the sketch works as a mask to highlight the outlines. Finally, the processed images are used in the existing salient detection models. Our contribution is that the salient detection with the sketches extracting image outline can effectively improve the accuracy. Results prove that the proposed algorithm is efficient and improves the performance of models.

关键词： Salient detection Line sketch Contour optimized algorithm

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Planning for performance: Enhancing achievable performance for MPI through persistent collective operations

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PARALLEL COMPUTING 2019年第Jan.期81卷 32-57页

作者： Holmes, Daniel J. Morgan, Bradley Skjellum, Anthony Bangalore, Purushotham V. Sridharan, Srinivas Univ Edinburgh EPCC Edinburgh EH9 3FD Midlothian Scotland Auburn Univ OIT Auburn AL 36849 USA Univ Tennessee SimCtr Chattanooga TN 37403 USA Univ Tennessee Dept Comp Sci & Engn Chattanooga TN 37403 USA Univ Alabama Birmingham Dept Comp Sci Birmingham AL 35294 USA Intel Corp 23-56POuter Ring Rd Bangalore 560017 Karnataka India

Advantages of nonblocking collective communication in MPI have been established over the past quarter century, even predating MPI-1. For regular computations with fixed communication patterns, significant additional optimizations can be revealed through the use of persistence (planned transfers) not currently available in the MPI-3 API except for a limited form of point-to-point persistence (aka half-channels) standardized since MPI-1. This paper covers the design, prototype implementation of LibPNBC (based on LibNBC), and MPI-4 standardization status of persistent nonblocking collective operations. We provide early performance results, using a modified version of NBCBench and an example application (based on 3D conjugate gradient) illustrating the potential performance enhancements for such operations. Persistent operations enable MPI implementations to make intelligent choices about algorithm and resource utilization once and amortize this decision cost across many uses in a long-running program. Evidence that this approach is of value is provided. As with non-persistent, nonblocking collective operations, the requirement for strong progress and blocking completion notification are jointly needed to maximize the benefit of such operations (e.g., to support overlap of communication with computation and/or other communication). Further enhancement of the current reference implementation, as well as additional opportunities to enhance performance through the application of these new APIs, comprise future work. (C) 2018 Published by Elsevier B.V.

关键词： MPI Collective communication Persistence Nonblocking optimized algorithm

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The investigation of thermo-economic performance and conceptual design for the miniaturized lead-cooled fast reactor composing supercritical CO2 power cycle

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ENERGY 2019年 173卷 174-195页

作者： Li, Ming-Jia Xu, Jin-Liang Cao, Feng Guo, Jia-Qi Tong, Zi-Xiang Zhu, Han-Hui Xi An Jiao Tong Univ Sch Energy & Power Engn Key Lab Thermofluid Sci & Engn Minist Educ Xian 710049 Shaanxi Peoples R China North China Elect Power Univ State Key Lab Alternate Elect Power Syst Renewabl Beijing 102206 Peoples R China

A comprehensive study of thermo-economic analysis and practical conceptual design of miniaturized lead-cooled fast reactor (LFR) composing supercritical CO2 power cycle is proposed in order to promote the real application in the market. The thermodynamic model and economic model are established based on the following five supercritical CO2 (S-CO2) Brayton cycles integrating with the miniaturized LFR, separately. Moreover, the optimization algorithm is adopted to optimize the key parameters of five power cycles with the objectives of maximizing the system thermoelectric conversion efficiency and electricity production costs (EPC) simultaneously. The optimal cycle and optimum parameters are obtained for the integrated system. Furthermore, the structural parameters of key components are confirmed based on the above results. The main subsidiary systems are designed. Finally, the practical design of LFR composing S-CO2 power cycle is carried out. The results shown that various parameters have different effects on the thermodynamic-economic performance of the system. The higher inlet temperature of turbine is beneficial to improve both thermodynamic and economic performance of the system. With the eta(t,sys)-EPC analyzed simultaneously, the recompression cycle is the optimal to operate with more working conditions. Its eta(t,sys) is from 36.68% to 44.46%, and EPC is from 0.050 $.kW(-1).h(-1) to 0.055 $.kW(-1).h(-1)). (C) 2019 Elsevier Ltd. All rights reserved.

关键词： Miniaturized lead-cooled fast reactor Thermo-economic performance S-CO2 brayton cycles optimized algorithm Investment analysis Conceptual design

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Multi-objective Ecological Dispatching of Reservoir Based on MOCEA/D algorithm

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JOURNAL OF COASTAL RESEARCH 2019年第Sup93期35卷 460-465页

作者： Shen, Qin Mo, Li Liu, Guanjun Huazhong Univ Sci & Technol Sch Hydropower & Informat Engn Wuhan 430074 Hubei Peoples R China

The rational planning and operation of the reservoir are complicated because of many variables and constraints. With the target of ensuring the safety of river ecosystems, this paper takes the Three Gorges Reservoir as the research object and constructs a multi-objective optimization model for power generation, ecological dispatching and minimum power output of the power station. The model results calculated by the multi-objective cultured evolutionary algorithm based on decomposition (MOCEA/D) indicate it is feasible to slightly reduce the benefits of the other two targets to increase ecological dispatching benefit. And the calculation results can obtain multiple optimal scheduling schemes with good convergence, which can provide scheduling solutions for large reservoirs.

关键词： Multi-objective optimization optimized algorithm ecological dispatching

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Extraction method of component waves in full waveform acoustic data and its application

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Global Geology 2020年第1期23卷 16-23页

作者： ZHOU Haoyi MO Xiuwen College of Geo-Exploration Science and Technology Jilin University

In conventional slowness-time coherence(STC)method,slowness and time need to be searched at the same time,which limits the precision and lowers the *** dichotomy method combined with slowness-time coherence algorithm aims to enhance the efficiency of data processing and to improve the *** algorithm changes the searching pattern of conventional slowness-time coherence method to acquire the slowness of component waves in array acoustic logging *** on energy ratio of short time window versus long time window and slowness-time coherence method,the algorithm first acquires the arrivals of the component waves using energy ratio of short time window versus long time window *** then uses the calculated results as the arrivals in conventional slowness-time coherence method,so the slowness-time two-dimensional searching process is simplified to slowness searching *** on dichotomy method,the searching pattern is further optimized in replace of the ergodic searching pattern in conventional slowness-time coherence method,which means that as the iteration proceeds,the current searching interval is reduced to half of the former,so the number of searching times is *** dichotomy method combined with slowness-time coherence algorithm is applied to well L in the data *** with conventional slowness-time coherence method,for compressional wave,the searching efficiency of the algorithm is 4.53 times better,while for Stoneley wave,the searching efficiency is 1.85 times *** with conventional logging data,the average absolute error of the results of the dichotomy method combined with slowness-time coherence algorithm is 1.14μs/ft smaller than that of the conventional method,while the average relative error is 1.2 percent *** dichotomy method combined with slowness-time coherence algorithm shows good results in its application,which can enhance the processing efficiency remarkably while getting reliable r

关键词： array acoustic logging slowness extraction slowness-time coherence method optimized algorithm

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optimized Context Weighting for the Compression of the Un-repetitive Genome Sequence Fragment

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WIRELESS PERSONAL COMMUNICATIONS 2018年第1期103卷 921-939页

作者： Chen, Min Li, Rui Yang, LiJun Yunnan Univ Informat Coll Kunming 650091 Yunnan Peoples R China HongHe Univ Coll Engn Mengzi 661199 Peoples R China Yunnan Police Coll Informat Secur Coll Kunming 650223 Yunnan Peoples R China

The details of context weighting is discussed first and some fomulas for describing the progress of context weighting is also given. During the weighting, the weighting cost can influence the performance of context modeling entropy coding. However, the context weighting rely on corresponding counting vectors which are joined in weighting. Meanwhile, the equivalence between context weighting and the weighting of description length implies that the weights can be optimized. The corresponding methods are discussed in details in our paper. At last, the proposed approach is used to compress these simple genome sequences. A large number of experiment results indicate that the corresponding compression results is better than the results of other existing algorithms.

关键词： Context weighting Weighting cost Genome compression optimized algorithm

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