Application of CFD and FEA Coupling to Predict Structural Dynamic Responses of A Trimaran in Uni-and Bi-Directional Waves

To predict the wave loads of a flexible trimaran in different wave fields,a one-way interaction numerical simulation method is proposed by integrating the fluid solver(Star-CCM+)and structural solver(Abaqus).Differing from the existing coupled CFD-FEA method for monohull ships in head waves,the presented method equates the mass and stiffness of the whole ship to the hull shell so that any transverse and longitudinal section stress of the hull in oblique waves can be obtained.Firstly,verification study and sensitivity analysis are carried out by comparing the trimaran motions using different mesh sizes and time step schemes.Discussion on the wave elevation of uni-and bi-directional waves is also carried out.Then a comprehensive analysis on the structural responses of the trimaran in different uni-directional regular wave and bi-directional cross sea conditions is carried out,respectively.Finally,the differences in structural response characteristics of trimaran in different wave fields are studied.The results show that the present method can reduce the computational burden of the two-way fluid-structure interaction simulations.

A chaotic hierarchical encryption/watermark embedding scheme for multi-medical images based on row-column confusion and closed-loop bi-directional diffusion

Security during remote transmission has been an important concern for researchers in recent years.In this paper,a hierarchical encryption multi-image encryption scheme for people with different security levels is designed,and a multiimage encryption(MIE)algorithm with row and column confusion and closed-loop bi-directional diffusion is adopted in the paper.While ensuring secure communication of medical image information,people with different security levels have different levels of decryption keys,and differentiated visual effects can be obtained by using the strong sensitivity of chaotic keys.The highest security level can obtain decrypted images without watermarks,and at the same time,patient information and copyright attribution can be verified by obtaining watermark images.The experimental results show that the scheme is sufficiently secure as an MIE scheme with visualized differences and the encryption and decryption efficiency is significantly improved compared to other works.

Cross-Lagged Relationship between Physical Activity Time,Openness and Depression Symptoms among Adolescents:Evidence from China

The relationship between physical activity time,openness and depression symptoms among adolescents is a cutting-edge research direction in the field,yet it remains unclear.This study is based on a sample of 7924 students from a nationally representative China Education Panel Survey database and examines the bidirectional relationships between physical activity time,openness and depression symptoms among Chinese adolescents.Descriptive analysis showed that during the 7th and 8th grades,the average physical activity time decreased to less than one hour per day,accompanied by a decreasing trend in openness and a slight worsening in depression symptoms.Correlation analysis showed a significant negative correlation between physical activity time and depression symptoms,a significant positive correlation between physical activity time and openness,and a significant negative correlation between depression symptoms and openness.The results from cross-lagged models indicated a bidirectional relationship between physical activity time and openness,with physical activity time significantly positively predicting openness in the following year and openness significantly positively predicting physical activity time in the following year.In addition,depression symptoms had a unidirectional negative predictive effect on openness.The conclusions provide empirical evidence for education administration and schools to promote the physical and mental health development of adolescents worldwide.

基于CAPE-OPEN标准的简捷炼油过程建模及常减压蒸馏流程在线模拟

简捷炼油过程模型广泛应用于运行监测、在线计算、实时优化等领域,但大多数模型只是将输入、输出变量进行关联,无法计算出各组分流量组成,难以集成在模拟软件中进行全流程模拟。本研究简化了炼油分离过程,开发了基于CAPE-OPEN标准的简捷炼油塔模型。首先,将炼油过程简化为连续的分离单元,根据实际产品数据校正模型参数,实现某一实际工况流程模拟;其次,将模型参数与实际工况操作变量数据相结合,采用径向基函数插值确定操作变量对模型参数的影响关系,实现多种工况流程模拟;最后,通过常减压蒸馏工业装置实例的3种工况进行验证。结果表明:各工况模拟结果与Aspen计算结果相比,初馏塔塔顶油馏出温度点偏差大多在2%以内,常减压蒸馏塔各侧线油的馏出温度点平均偏差在3%以内;与实际结果相比,平均误差都在5%以内,符合工程允许误差范围要求。所建模型的计算速度快,各塔均在0.2 s左右完成计算,适用于在线生产、调度等。

我国高质量教育资源供给机制创新与路径研究——来自美国“#GoOpen”计划的启示

数字化是当下教育改革的重点,也是未来教育发展的趋势。无论是作为“十四五”规划中的战略举措,还是党的二十大中提出的必然要求,构建数字化教育资源为主体的高质量教育资源体系在当下具有必要性与迫切性。美国#GoOpen计划自实施以来,在教育资源数字化、个性化、均等化三个方面均取得了一定成果。通过对该计划官方文件与政策进行解读,对其内涵与特点进行分析,我国在进行高质量教育资源建设及其供给路径探究过程中应当重视统筹规划,循序渐进,同时完善多重考核与评估机制,结合社会多方力量,保证每个学习者的享有权利,最终走向教育公平,共同发展。

基于YOLO-OpenMax的水声通信信号开集识别方法

水声通信信号调制方式随着技术进步从典型的传统调制方式发展为水声通信机厂商私有开发的新型调制方式,这使得现有的水声通信信号闭集调制识别技术实用性受到制约,但现阶段鲜有研究基于深度学习的水声通信信号调制方式的开集识别方法。针对此现状,提出一种基于YOLO图像检测识别网络和OpenMax模型的开集识别方法。利用YOLOv5网络的输出特点,将传统OpenMax模型的处理方法进行改进,提出一种两步测试方法,实现了在多径信道下的水声通信信号的开集识别。仿真实验表明:在归一化系数为0.5,信噪比等于10 dB条件下的归一化开集识别准确率达到90%以上,实测数据同样验证了本文方法的有效性。

Text Sentiment Analysis Based on Multi-Layer Bi-Directional LSTM with a Trapezoidal Structure

Sentiment analysis,commonly called opinion mining or emotion artificial intelligence(AI),employs biometrics,computational linguistics,nat-ural language processing,and text analysis to systematically identify,extract,measure,and investigate affective states and subjective data.Sentiment analy-sis algorithms include emotion lexicon,traditional machine learning,and deep learning.In the text sentiment analysis algorithm based on a neural network,multi-layer Bi-directional long short-term memory(LSTM)is widely used,but the parameter amount of this model is too huge.Hence,this paper proposes a Bi-directional LSTM with a trapezoidal structure model.The design of the trapezoidal structure is derived from classic neural networks,such as LeNet-5 and AlexNet.These classic models have trapezoidal-like structures,and these structures have achieved success in the field of deep learning.There are two benefits to using the Bi-directional LSTM with a trapezoidal structure.One is that compared with the single-layer configuration,using the of the multi-layer structure can better extract the high-dimensional features of the text.Another is that using the trapezoidal structure can reduce the model’s parameters.This paper introduces the Bi-directional LSTM with a trapezoidal structure model in detail and uses Stanford sentiment treebank 2(STS-2)for experiments.It can be seen from the experimental results that the trapezoidal structure model and the normal structure model have similar performances.However,the trapezoidal structure model parameters are 35.75%less than the normal structure model.

A Modified Bi-Directional Evolutionary Structural Optimization Procedure with Variable Evolutionary Volume Ratio Applied to Multi-Objective Topology Optimization Problem

Natural frequency and dynamic stiffness under transient loading are two key performances for structural design related to automotive,aviation and construction industries.This article aims to tackle the multi-objective topological optimization problem considering dynamic stiffness and natural frequency using modified version of bi-directional evolutionary structural optimization(BESO).The conventional BESO is provided with constant evolutionary volume ratio(EVR),whereas low EVR greatly retards the optimization process and high EVR improperly removes the efficient elements.To address the issue,the modified BESO with variable EVR is introduced.To compromise the natural frequency and the dynamic stiffness,a weighting scheme of sensitivity numbers is employed to form the Pareto solution space.Several numerical examples demonstrate that the optimal solutions obtained from the modified BESO method have good agreement with those from the classic BESO method.Most importantly,the dynamic removal strategy with the variable EVR sharply springs up the optimization process.Therefore,it is concluded that the modified BESO method with variable EVR can solve structural design problems using multi-objective optimization.

Wave propagation responses of porous bi-directional functionally graded magneto-electro-elastic nanoshells via nonlocal strain gradient theory

This study examines the wave propagation characteristics for a bi-directional functional grading of barium titanate(BaTiO_(3)) and cobalt ferrite(CoFe_(2)O_(4)) porous nanoshells,the porosity distribution of which is simulated by the honeycomb-shaped symmetrical and asymmetrical distribution functions.The nonlocal strain gradient theory(NSGT) and first-order shear deformation theory are used to determine the size effect and shear deformation,respectively.Nonlocal governing equations are derived for the nanoshells by Hamilton's principle.The resulting dimensionless differential equations are solved by means of an analytical solution of the combined exponential function after dimensionless treatment.Finally,extensive parametric surveys are conducted to investigate the influence of diverse parameters,such as dimensionless scale parameters,radiusto-thickness ratios,bi-directional functionally graded(FG) indices,porosity coefficients,and dimensionless electromagnetic potentials on the wave propagation characteristics.Based on the analysis results,the effect of the dimensionless scale parameters on the dispersion relationship is found to be related to the ratio of the scale parameters.The wave propagation characteristics of nanoshells in the presence of a magnetoelectric field depend on the bi-directional FG indices.

OPENING TO THE CHALLENGE --An economy thrives in openness and withers in seclusion

pening-up has always been a hot topic at the China International Import Expo(CIIE),the world's first import expo held at the national level.During the sixth CIIE,the Hongqiao International Economic Forum held on November 6 attracted many participants from government departments,academia,and the business sector to conduct in-depth discussions on global trade and the challenges it faces.Participants agreed that multi-party dialogue is key to the issue.

Toward a sustainable future:Examining the interconnectedness among Foreign Direct Investment(FDI),urbanization,trade openness,economic growth,and energy usage in Australia

The energy demand in Australia is increasing with the industrialization and rapid economic growth.This study analyzed the relationships among the economic growth,Foreign Direct Investment(FDI),trade openness,urbanization,and energy usage in Australia based on the data from World Development Indicators(WDI)from 1972 to 2021.The results indicates that there is a cointegration among economic growth,FDI,trade openness,urbanization,and energy usage,which was traced through the autoregressivedistributed lag(ARDL).The Zivot-Andrews unit root test reveals that energy usage,economic growth,FDI,urbanization,and trade openness show significant structural breaks in 1993,1996,1982,2008,and 1994,respectively.The ARDL model shows that economic growth has a positive and significant effect on energy usage in the long-run(0.814)and short-run(0.809).Moreover,the results also show that FDI(0.028)and trade openness(0.043)have positive impacts on energy usage in the long-run.However,urbanization shows a negative and significant influence on energy usage in the long-run(–0.965).Then,the research demonstrates a unidirectional causation between energy usage and trade openness,with energy usage significantly causing trade openness.The current study endorses energy consumption policies and investment strategies for a paradigm shifting from a reliance on fossil fuels as the primary energy source to renewable energy sources.These findings have profound implications for sustainable energy usage.

Artificial Self-Recovery Opens up a New Journey of Autonomous Health of Mechanical Equipments

1.Introduction With the implementation of modern production strategies,such as“Industry 4.0”and“Made in China 2025,”the development of high-end mechanical equipment is gradually reaching a high degree of parameterization,digitalization,networking,and intelligence[1].High-end mechanical equipment no longer consists of traditional single devices,but is closely linked to the overall production process;that is,a variety of devices interact with each other and collectively form a complex system.However,faults can lead to production delays throughout the system and even seriously threaten the safety of workers[2].In addition,equipment operating in unmanned air or space vehicles(including space robots)cannot be repaired by humans if they break down[3].Until recently,the typical method of addressing machine faults was primarily the“fault cure”method,which involves manually shutting down,inspecting,and repairing the equipment to restore normal operation.Accordingly,the maintenance cycle of the traditional“fault cure”method is time-consuming,and the quality of the maintenance depends on the skills of the technician[4].

Dust-Holding Capacity and Bio-Chemical Changes of Plant Species Growing in an Around Opencast Mining Area of Bundelkhand Region of Uttar Pradesh, India

The present study has been carried out on a total of 50 available plant species to assess their dust-capturing capacity and biochemical performances in and around open cast granite mine areas of Jhansi district and Bundelkhand University campus treated as control site. Plant species existing under a polluted environment for a long time may be considered as potentially resistant species and recommended for green belt design in mining areas, especially to cope with dust pollution. Results showed the pollution level, especially of mining-originated dust particles holding capacity of leaves and effects of different biochemical parameters (Total Chlorophyll, Protein and Carotenoid) of existing plant species both from mining areas as well as from Bundelkhand University campus. Based on their performances, Tectona grandis L., Ficus hispida L., Calotropis procera Aiton., Butea monosperma Lam. and Ficus benghalensis L., etc. are highly tolerant species while Ficus infectoria L., Artocarpus heterophyllus Lam., Ipomoea purpurea L., Allianthus excelsa Roxb. and Bauhinia variegata L. are intermediate tolerant species. T. grandis had shown the highest dust-holding capacity (2.566 ± 0.0004 mg/cm2) whereas Albizia procera (0.018 ± 0.0002 mg/cm2) was found to be the lowest dust-holding capacity. Our findings also showed that the T. grandis and F. hispida have significant dust deposition with minimal effect of dust on their leaf chlorophyll (17.447 ± 0.019 mg/g and 14.703 ± 0.201 mg/g), protein (0.699 ± 0.001 mg/g and 0.604 ± 0.002 mg/g) and carotenoid (0.372 ± 0.003 mg/g and 0.354 ± 0.003 mg/g) content respectively among all selected plant species. Therefore, in the present investigation, plant species with high tolerance to high dust-holding capacity on their leaf surfaces are preferable for green corridors as open cast granite mines and their adjacent areas.

基于CAPE-OPEN标准的乙苯脱氢反应器模块开发与全流程模拟

基于某乙苯负压绝热脱氢制苯乙烯装置转化率低于设计值的现状,建立了包括小分子水蒸气转化反应在内的乙苯绝热脱氢制苯乙烯反应动力学模型和反应器模型,基于工业数据,估计了模型动力学参数,模型具有较高的精度;采用C++语言和COM技术开发了符合CAPE-OPEN标准的乙苯脱氢制苯乙烯反应器单元模块;在Aspen Plus平台构建了内嵌反应器模块的乙苯脱氢制苯乙烯全流程模型,反应器与精馏塔的模拟结果与实际相吻合;进一步考察了工艺参数对装置运行中期反应的影响,提出了适宜的工艺参数,为乙苯脱氢制苯乙烯的工艺设计、生产优化提供有益的支持。

Effect of Mouth Opening Training Stick Combined with Oral Massage on Mouth Opening Difficulty in Head and Neck Cancer Patients after Treatment

Objective: To study the application effect of mouth-opening training sticks combined with oral massage on patients with mouth-opening difficulty after treatment for head and neck cancer. Methods: Using convenient sampling, 60 patients with mouth-opening difficulty after treatment for head and neck cancer admitted to the Oncology Department from February 2022 to October 2023 were selected for a 2-week exercise and nursing program. The patients were divided into a control group (February 1, 2022 to November 30, 2022) and an observation group (December 1, 2022 to October 31, 2023), with 30 patients in each group. The control group underwent routine mouth-opening functional exercises combined with cork for oral support training, while the observation group underwent routine mouth-opening functional exercises combined with oral massage and mouth-opening training sticks for oral support training. The mouth-opening degree, mouth-opening difficulty level, comfort level, compliance, and quality of life were observed in both groups. Results: Before the intervention, there were no statistically significant differences in mouth-opening degree and mouth-opening difficulty level between the two groups (P > 0.05). After the intervention, the mouth-opening degree, mouth-opening difficulty level, oral comfort level, compliance, and QLICP-HN scores in the observation group were all better than those in the control group, with statistically significant differences (P < 0.05). Conclusion: The combination of mouth-opening training sticks and oral massage with mouth-opening functional exercises can effectively improve the degree of mouth-opening difficulty, enhance oral comfort, increase compliance with mouth-opening exercises, and improve quality of life.

Establishment and evaluation of an improved rat model of open abdomen

Introduction:This study aimed to establish an animal model of open abdomen(OA)through temporary abdominal closure via different techniques.Methods:Adult male Sprague-Dawley rats were randomly divided into three groups:group A(OA with polypropylene mesh alone);group B(OA with polypro-pylene mesh combined with a patch);and group C(OA with polypropylene mesh and a sutured patch).Vital signs,pathophysiological changes,and survival rates were closely monitored in the rats for 7 days after surgery.Abdominal X-rays and histopathological examinations were performed to assess abdominal organ changes and wound healing.Results:The results showed no significant difference in mortality rates among the three groups(p>0.05).However,rats in group B exhibited superior overall condi-tion,cleaner wounds,and a higher rate of wound healing compared to the other groups(p<0.05).Abdominal X-rays indicated that varying degrees of distal intestinal obstruction in all groups.Histopathological examinations revealed fibrous hyperpla-sia,inflammatory cell infiltration,neovascularization,and collagen deposition in all groups.Group B demonstrated enhanced granulation tissue generation,neovasculari-zation,and collagen deposition compared to the other groups(p<0.05).Conclusions:Polypropylene mesh combined with patches is the most suitable method for establishing an animal model of OA.This model successfully replicated the patho-logical and physiological changes in postoperative patients with OA,specifically the progress of abdominal skin wound healing.It provides a practical and reliable animal model for OA research.

OpenAI发布首个文生视频模型Sora

2024年2月16日,OpenAI发布首个文生视频模型Sora。Sora模型可以通过文本描述生成60秒长视频,还可以对视频色彩风格等要素精确理解,创造出人物表情丰富、情感生动的视频内容。据介绍,Sora模型有三大突出亮点,实现了AIGC领域的里程碑式进展。

Open-Source Software Defined Networking Controllers:State-of-the-Art,Challenges and Solutions for Future Network Providers

Software Defined Networking(SDN)is programmable by separation of forwarding control through the centralization of the controller.The controller plays the role of the‘brain’that dictates the intelligent part of SDN technology.Various versions of SDN controllers exist as a response to the diverse demands and functions expected of them.There are several SDN controllers available in the open market besides a large number of commercial controllers;some are developed tomeet carrier-grade service levels and one of the recent trends in open-source SDN controllers is the Open Network Operating System(ONOS).This paper presents a comparative study between open source SDN controllers,which are known as Network Controller Platform(NOX),Python-based Network Controller(POX),component-based SDN framework(Ryu),Java-based OpenFlow controller(Floodlight),OpenDayLight(ODL)and ONOS.The discussion is further extended into ONOS architecture,as well as,the evolution of ONOS controllers.This article will review use cases based on ONOS controllers in several application deployments.Moreover,the opportunities and challenges of open source SDN controllers will be discussed,exploring carriergrade ONOS for future real-world deployments,ONOS unique features and identifying the suitable choice of SDN controller for service providers.In addition,we attempt to provide answers to several critical questions relating to the implications of the open-source nature of SDN controllers regarding vendor lock-in,interoperability,and standards compliance,Similarly,real-world use cases of organizations using open-source SDN are highlighted and how the open-source community contributes to the development of SDN controllers.Furthermore,challenges faced by open-source projects,and considerations when choosing an open-source SDN controller are underscored.Then the role of Artificial Intelligence(AI)and Machine Learning(ML)in the evolution of open-source SDN controllers in light of recent research is indicated.In addition,the challenges and limitations associated with deploying open-source SDN controllers in production networks,how can they be mitigated,and finally how opensource SDN controllers handle network security and ensure that network configurations and policies are robust and resilient are presented.Potential opportunities and challenges for future Open SDN deployment are outlined to conclude the article.

Atomically Dispersed Ruthenium Catalysts with Open Hollow Structure for Lithium-Oxygen Batteries

Lithium–oxygen battery with ultrahigh theoretical energy density is considered a highly competitive next-generation energy storage device,but its practical application is severely hindered by issues such as difficult decomposition of discharge products at present.Here,we have developed N-doped carbon anchored atomically dispersed Ru sites cathode catalyst with open hollow structure(h-RuNC)for Lithium–oxygen battery.On one hand,the abundance of atomically dispersed Ru sites can effectively catalyze the formation and decomposition of discharge products,thereby greatly enhancing the redox kinetics.On the other hand,the open hollow structure not only enhances the mass activity of atomically dispersed Ru sites but also improves the diffusion efficiency of catalytic molecules.Therefore,the excellent activity from atomically dispersed Ru sites and the enhanced diffusion from open hollow structure respectively improve the redox kinetics and cycling stability,ultimately achieving a high-performance lithium–oxygen battery.

Suicide risk in juvenile open angle glaucoma patients

AIM:To investigate the association between juvenile open angle glaucoma(JOAG)and mental health among Koreans.METHODS:This study used nationally representative data from the 8th Korea National Health and Nutrition Examination Survey(KNHANES)2021.Glaucoma diagnosis followed the International Society of Geographical and Epidemiological Ophthalmology criteria based on glaucomatous structural defects,visual field defects,corrected vision,and intraocular pressure.As outcomes,suicidal behaviors,psychiatric counseling,and depression were evaluated through mental health questionnaires.Odds ratios(ORs)with 95%confidence intervals(CIs)were estimated using logistic regression models,adjusting for covariates.RESULTS:Among 7090 participants,3446 met the inclusion criteria for analysis,and 88(2.6%)were diagnosed with open angle glaucoma(OAG).After adjusting for age,sex,and best-corrected visual acuity(VA),participants with OAG were revealed to have significantly higher odds of suicidal behaviors(i.e.,ideation,planning,or attempts)compared with those without OAG(OR:2.70;95%CI:1.12-6.54;P=0.028).This association remained significant after further adjustments for socioeconomic status,lifestyle factors,and presence of chronic conditions(P=0.031 and 0.035,respectively).However,there was no significant difference for the other two outcomes,psychiatric counseling and depression.An age-stratified analysis revealed a stronger association between OAG and suicidal behaviors in younger JOAG participants(<40y)than in older OAG participants(≥40y;OR:3.80 vs 2.22;95%CI:0.79-18.22 vs 0.56-8.80,respectively).CONCLUSION:OAG patients show a higher risk of suicidal behaviors than those without glaucoma particularly in JOAG patients.