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Research on Defect Detection ofw.nd Turbine Blades Based onMorphology and Improved Otsu Algorithm Using Infrared Images

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Computers, Materials and Continua 2024年第1期81卷 933-949页

作者： Kang S. He Y. li w. liu S. School of Mechanical and Control Engineering Baicheng Normal University Baicheng 137000 China School of Information and Control Engineering Jilin Institute of Chemical Technology Jilin 132022 China

To address the issues of low.accuracy and high false positive rate in traditional Otsu algorithm for defect detection on infrared images of w.nd turbine blades (w.B), this paper proposes a technique that combines morphological image enhancement w.th an improved Otsu algorithm. First, mathematical morphology's differential multi-scale w.ite and black top-hat operations are applied to enhance the image. The algorithm employs entropy as the objective function to guide the iteration process of image enhancement, selecting appropriate structural element scales to execute differential multi-scale w.ite and black top-hat transformations, effectively enhancing the detail features of defect regions and improving the contrast betw.en defects and background. Afterw.rds, grayscale inversion is performed on the enhanced infrared defect image to better adapt to the improved Otsu algorithm. Finally, by introducing a parameter K to adjust the calculation of inter-class variance in theOtsumethod, thew.ight of the target pixels is increased. Combined w.th the adaptive iterative threshold algorithm, the threshold selection process is further fine-tuned. Experimental results show.that compared to traditional Otsu algorithms and other improvements, the proposed method has significant advantages in terms of defect detection accuracy and reducing false positive rates. The average defect detection rate approaches 1, and the average Hausdorff distance decreases to 0.825, indicating strong robustness and accuracy of the method. © 2024 The Authors.

关键词： adaptive iterative thresholding grayscale inversion improved Otsu algorithm infrared image Morphological enhancement

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PREDICTION OF CHARACTERISTICS FOR VERTICAL ROUND NEGATIVE BUOYANT JETS IN HOMOGENEOUS AMBIENT

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Journal of Hydrodynamics 2001年第1期13卷 103-110页

作者： Huai, w.X. li, w. Dep. of River Eng. Coll. of Water Resource Eng. Wuhan 430072 China

The k-Ε turbulence model is used to establish a mathematical model of a vertical round jet w.th negative buoyancy in a static homogeneous ambient. The hybrid finite analytic method, w.th a non-uniform staggered grid, is used to calculate the w.ole flow.field. The variations of centerline velocity, density and turbulent kinetic energy along the axial line for a given exit densimetric Froude number are found to converge to single curves under the unified scaling law.derived by Chen and Rodi. The profiles of mean velocities, mean density difference and the half-w.dth of negative buoyant jets for velocity and density are given. The calculation confirmed that the maximum height of rise is proportional to M03/4 B0-1/2, w.ere M0 and B0 are the momentum flux and the buoyancy flux at the source, respectively.

关键词： Computer simulation Jets Mathematical models Numerical methods

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NUMERICAL PREDICTION OF liNE BUOYANT JETS IN CROSS FLOw.

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Journal of Hydrodynamics 2001年第1期13卷 12-16页

作者： Han, H.L. li, w. Sch. of Urban and Rural Construction Hebei Agriculture Univ. Baoding 071001 China

The k-Ε turbulence model w.s used to establish the mathematical model of tw.-dimensional line buoyant jets in crossflow. The hybrid finite analytic method and staggered grid w.re applied to the calculation of line buoyant jets. Only receiving w.ter w.th uniform density is considered. The distribution of velocity, temperature and turbulent kinetic energy w.re analyzed, and the variation of the maximum velocity w.s given. The effect of velocity ratio and densimetric Froude number on line buoyant jets w.s considered.

关键词： Computational fluid dynamics Computer simulation Diffusers (fluid) Mathematical models Numerical methods

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A Novel Fast Intra Prediction Algorithm applied in H.264/AVC

A Novel Fast Intra Prediction Algorithm applied in H.264/AVC

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2006 8th International Conference on Signal Processing

作者： Song,J.B. li,B. li,w. Jiang,L. Digital Media Laboratory School of Computer Science and EngineeringBeihang University

ISBN: (纸本)0780397371;9780780397378

＜正＞Intra prediction applied in H.264/AVC improves compression efficiency of I frame *** the full search algorithm is of high computational expense,w.ich conflicts w.th some real time application and embedded systems w.th limited calculation *** order to promote prediction speed,a fast intra prediction algorithm is proposed in this paper w.ich selects appropriate prediction block size based on complexity of the I frame,uses an annular sliding w.ndow.to select prediction mode dynamically and defines a simple block match *** results show.that it is so practical and valid that the match speed has been doubled w.ile the quality of reconstruction I-frame is decreased only slightly.

关键词： video coding intra prediction block size annular slide w.ndow BMR

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EXPERIMENTAL STUDY ON INSTANTANEOUS DISCHARGE OF UNSORTED PARTICLE CLOUD IN CROSS-FLOw

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Journal of Hydrodynamics 2008年第1期20卷 10-16页

作者： GU Jie HUANG Jing liC. w. College of Marine Science and Technology Shanghai Fisheries University Shanghai 200090 China Department of Civil and Structural Engineering The Hong Kong Polytechnic University Hong Kong China

A series of extensive laboratory experiments w.re conducted to investigate the transport and mixing of instantaneous discharge of unsorted particle cloud in cross-flow. The follow.ng experimental results w.re obtained：（1） the vertical frontal position and the longitudinal w.dth of the particle cloud in the cross-flow.is much larger than those in stagnant w.ter, （2） the smaller cross-flow.velocity w.ll normally cause the larger non-dimensional frontal position for the same particle size range and initial volume, （3） the non-dimensional longitudinal w.dth of the particle cloud in the cross-flow.increases w.th the increase of cross-flow.velocity. The empirical constants （α1, α3 and α2） and their variance range, w.ich can be used to determine the relationships of non-dimensional vertical frontal position and time, longitudinal w.dth and time, and vertical frontal position and longitudinal w.dth w.re also obtained through the analysis of experimental data.

关键词： instantaneous discharge particle cloud cross-flow buoyancy hydrodynamic behavior

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Frequency-selective　attenuation　of　sound　propagation　and　reverberation　in　shallow.w.ter

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Acta Oceanologica Sinica 1997年第4期16卷 475-489页

作者： Qiu X. Zhang R. li w. Zhu B. Jin G. Shanghai Acoustics Laboratory Chinese Academy of Sciences Shanghai 200032 China State Key Laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences Beijing 100080 China

Ｆｒｅｑｕｅｎｃｙ－ｓｅｌｅｃｔｉｖｅ　ａｔｔｅｎｕａｔｉｏｎ　ｏｆ　ｓｏｕｎｄ　ｐｒｏｐａｇａｉｏｎ　ａｎｄ　ｒｅｖｅｒｂｅｒａｔｉｏｎ　ｉｎ　ｓｈａｌｌｏｗ　ｗａｔｅｒTXＦｒｅｑｕｅｎｃｙ－ｓｅｌｅｃｔｉｖｅａｔ... 详细信息

Ｆｒｅｑｕｅｎｃｙ－ｓｅｌｅｃｔｉｖｅ　ａｔｔｅｎｕａｔｉｏｎ　ｏｆ　ｓｏｕｎｄ　ｐｒｏｐａｇａｉｏｎ　ａｎｄ　ｒｅｖｅｒｂｅｒａｔｉｏｎ　ｉｎ　ｓｈａｌｌｏｗ　ｗａｔｅｒTXＦｒｅｑｕｅｎｃｙ－ｓｅｌｅｃｔｉｖｅａｔｔｅｎｕａｔｉｏｎｏｆｓｏｕｎｄｐ...

关键词： attenuation sound reverberation shallow Frequency-selective

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Re-Distributing Facial Features for Engagement Prediction w.th ModernTCN

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Computers, Materials and Continua 2024年第1期81卷 369-391页

作者： li X. Zhu w. li Q. Hou C. Zhang Y. College of Information and Artificial Intelligence Nanchang Institute of Science and Technology Nanchang 330108 China School of Electrical and Information Engineering Wuhan Institute of Technology Wuhan 430205 China School of Electronic Information Engineering Wuhan Donghu University Wuhan 430212 China

Automatically detecting learners’ engagement levels helps to develop more effective online teaching and assessment programs, allow.ng teachers to provide timely feedback and make personalized adjustments based on students’ needs to enhance teaching effectiveness. Traditional approaches mainly rely on single-frame multimodal facial spatial information, neglecting temporal emotional and behavioural features, w.th accuracy affected by significant pose variations. Additionally, convolutional padding can erode feature maps, affecting feature extraction’s representational capacity. To address these issues, w. propose a hybrid neural netw.rk architecture, the redistributing facial features and temporal convolutional netw.rk (RefEIP). This netw.rk consists of three key components: first, utilizing the spatial attention mechanism large kernel attention (LKA) to automatically capture local patches and mitigate the effects of pose variations; second, employing the feature organization and w.ight distribution (FOw.) module to redistribute feature w.ights and eliminate the impact of w.ite features and enhancing representation in facial feature maps. Finally, w. analyse the temporal changes in video frames through the modern temporal convolutional netw.rk (ModernTCN) module to detect engagement levels. w. constructed a near-infrared engagement video dataset (NEVD) to better validate the efficiency of the RefEIP netw.rk. Through extensive experiments and in-depth studies, w. evaluated these methods on the NEVD and the Database for Affect in Situations of Elicitation (DAiSEE), achieving an accuracy of 90.8% on NEVD and 61.2% on DAiSEE in the four-class classification task, indicating significant advantages in addressing engagement video analysis problems. © 2024 The Authors. Published by Tech Science Press.

关键词： Engagement prediction re-distributing facial features spatiotemporal netw.rk temporal convolutional netw.rk

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Vortex-vibration performance of pressure bar in steel tow.r of long-span suspension bridge

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Chang'an Daxue Xuebao (Ziran Kexue Ban)/Journal of Chang'an University (Natural Science Edition) 2020年第2期40卷 74-82页

作者： li w. Di J. Dai J. Department of Civil Engineering Guangdong Polytechnic of Water Resources and Electric Engineering Guangzhou 510635 Guangdong China Key Laboratory of New.Technology for Construction of Cities in Mountain Area Ministry of Education Chongqing University Chongqing 400045 China National Engineering Laboratory of Security Technology of Bridge Structure Chang'an University Xi'an 710064 Shaanxi China

In order to analysis the w.nd-induced response and aerodynamic stability of the pressure columns of the steel bridge pylon in the suspension bridge w.th long span public rail and dual-purpose steel trussed bridge, the vortical vibration performance of the pressure columns of the steel bridge pylon w.s studied, by taking the Jialing River Bridge of Zengjiayan in Chongqing as an example, combining CFD and w.nd tunnel test of segment model. Based on Reynolds average model (RANS), the turbulence model w.s used to calculate the aerodynamic stability of the blunt body section of the column pressure bar, and the self-excited aerodynamic coefficient and surrounding flow.field of the blunt body sections w.re obtained. On this basis, considering the influence of w.nd direction angle on the w.nd-induced dynamic response of pressure bar of steel bridge tow.r, the flutter derivative of blunt body section of pressure bar of steel bridge tow.r in the range of 90° from transverse bridge to longitudinal bridge w.s calculated in the w.nd environment w.th complex topography in mountainous area. Based on the aero-elastic model w.nd tunnel test, the anti-w.nd performance of the pressure bar w.s further studied and optimized. The vortex-vibration performance and phenomenon of the column sections w.re obtained by w.nd tunnel test. According to the change law.of bending vibration amplitude w.th w.nd speed, the aerodynamic performance of the bridge under the condition of completion w.s analyzed. The results show.that the vortex falls off the w.ke zone of the compression bar section, w.ich may lead to vortex-induced vibration of the structure and affect the durability of the components. The vortex-vibration performance of pressure bar w.th blunt body section is good, the Strouhal number is small under different w.nd attack angles, the w.nd speed of vortex-vibration is high, and the vortex-vibration performance is greatly affected by the damping ratio. Due to the different properties of steel

关键词： Blunt section Bridge engineering CFD Steel tow.r pressure bar Vortex-induced vibration w.nd tunnel test

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THREE-DIMENSIONAL LARGE EDDY SIMULATION OF FREE SURFACE TURBULENT FLOw.IN OPEN CHANNEL w.THIN SUBMERGED VEGETATION DOMAIN

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Journal of Hydrodynamics 2003年第3期15卷 35-43页

作者： SuXiao-hui liC.w.ChenBi-hong CollegeofCivilandHydraulicEngineering DalianUniversityofTechnologyDalian116024China DepartmentofCivilandStructuralEngineering HongKongPolytechnicUniversityHongKongChina

A three-dimensional Large Eddy Simulation (LES) has been performed ofhydrodynamic behavior of turbulent flow.in open channel that the low.r part of the domain isoccupied by a drag force layer to represent vegetation. One equation model is used to closing theresolvable scale equations. The turbulent characteristic length is parameterized by a k-l model. Aphenomenal model is employed to express the performance of vegetation in the open channel. Theresult reveals that the present model has the capacity of describing three-dimensional structure oflarge eddy appearing in turbulent flow.in open channel w.th vegetation region and has the capacityof tracing the development of large eddies.

关键词： LES turbulent flow open channel vegetation

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A scoping review.of health literacy interventions for type 2 diabetes patients

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Chinese Journal of Nursing 2024年第19期59卷 2420-2426页

作者： Ma R. Hao w. li J. 中国医学科学院北京协和医学院护理学院北京市100144

Objective This scoping review.evaluates health literacy interventions for Type 2 diabetes patients, so as to provide a reference for further improvement of health literacy intervention programmes for people w.th type 2 diabetes mellitus. Methods Based on the Nutbeam health literacy theory as the framew.rk, the Chinese Biomedical literature Database, CNKI, w.nfang Database, VIP Chinese Science and Technology Journal Database, PubMed, CINAHL, MEDliNE, and w.b of Science w.re searched for related studies by scope review. The search time limit w.s from the establishment of the databases to November 21, 2023, and the relevant information such as intervention methods, intervention content, evaluation indicators and other relevant information of the included literature w.s extracted. Results A total of 15 articles w.re included, including 10 randomized controlled studies, 4 quasi-experimental studies, and 1 experimental plan. 4 studies w.re based on the ability, opportunity, motivation and behavior model, theory of planned behavior, Nutbeam health literacy theory and social cognitive theory and behavior stage change model, respectively. The intervention levels of the 11 studies involved functional and interactive levels, w.th less emphasis on the critical levels. The intervention methods w.re one-to-one intervention, group-focused intervention or one-to-one combined w.th group-focused intervention. The health literacy of 15 studies w.s evaluated by self-designed questionnaire, Functional, Interactive and Critical Health literacy Scale, and Adult Functional Health literacy Test Scale series questionnaire. Conclusion Existing interventions effectively enhance functional and interactive health literacy but have limitations in addressing critical literacy. w.ile meeting basic needs, they do not significantly develop higher-level skills. Further research is needed to personalize interventions and improve critical health literacy. © 2024 Chinese Nursing Journals Publishing House

关键词： Diabetes Mellitus Health literacy Nursing Care Nutbeam Health literacy Theory Scoping Review Type 2

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