Comparative analysis of empirical and deep learning models for ionospheric sporadic E layer prediction

Sporadic E(Es)layers in the ionosphere are characterized by intense plasma irregularities in the E region at altitudes of 90-130 km.Because they can significantly influence radio communications and navigation systems,accurate forecasting of Es layers is crucial for ensuring the precision and dependability of navigation satellite systems.In this study,we present Es predictions made by an empirical model and by a deep learning model,and analyze their differences comprehensively by comparing the model predictions to satellite RO measurements and ground-based ionosonde observations.The deep learning model exhibited significantly better performance,as indicated by its high coefficient of correlation(r=0.87)with RO observations and predictions,than did the empirical model(r=0.53).This study highlights the importance of integrating artificial intelligence technology into ionosphere modelling generally,and into predicting Es layer occurrences and characteristics,in particular.

Optimization of Urban Ecological Network Based on MSPA-MCR Model: A Case Study of Jingzhou City

As a key carrier supporting urban ecological health and living environment quality,urban ecological network is a key focus of current urban green space research.Jingzhou City of Hubei Province is taken as the research object.Relying on GIS technology platform,MSPA method is used to analyze the landscape pattern of Jingzhou City.On this basis,the landscape connectivity evaluation method is used to accurately identify and extract the source areas with important ecological value in Jingzhou City.Then,the normalization method and weighting method are combined to create a resistance factor evaluation system to construct the resistance surface.Based on the MCR model,the ecological network of Jingzhou City is successfully constructed,and targeted spatial optimization strategies and development suggestions are proposed.

基于ERA和MCR模型的生态安全格局构建——以陕西沿黄地区为例

本研究通过构建多风险源指标体系进行陕西沿黄地区生态风险等级评价,利用土地利用数据,探讨研究区近20a的景观结构变化特征;采用“源地—阻力面—廊道”范式构建研究区生态安全格局,确定生态节点和生态断裂点,提出区域生态保护优化建议.结果表明:(1)研究区内,生态风险空间分布特征存在显著差异,低值区主要分布在北部和南部,高值区主要分布在中部;(2)研究区近20a生态核心区面积明显增多,但仍然较为破碎,支线占比减少,连通度较低;(3)现有22个重要生态源地,总面积4655.73km^(2),共提取53条重要生态廊道,整体构成“一带三区多廊”的生态安全格局;识别出43个生态节点和98个生态断裂点.其中研究区北部生态廊道和生态节点较为密集.(4)研究区生态网络闭合度低,南北连通性差.未来需要结合区域生态风险等级,通过规划踏脚石斑块、修复生态断裂点、提升9条潜在廊道等方式优化生态安全格局.本研究可为陕西沿黄地区自然生态系统和生物多样性的保护提供科学依据,助力黄河流域生态保护和高质量发展.

欧盟碳边境调节机制与中国出口贸易绿色低碳演化前瞻——基于GTAP-E模型的预测研究

探究以欧盟碳边境调节机制(CBAM)为代表的碳关税贸易壁垒对中国出口贸易的影响,对研究中国出口贸易绿色低碳演化路径具有重要意义。因此可以构建多种碳关税征收情景,并通过GTAP-E模型进行递归模拟,预测欧盟碳边境调节机制正式实施后碳关税壁垒和中国出口贸易变化。研究发现:CBAM将对中国出口贸易竞争力带来负面效应,可加强多边对话与协商,共同制定应对措施降低影响;欧盟进口需求下滑,中国对欧出口通道受阻,机械设备及交通运输制造业首当其冲,应继续积蓄优势产业出口动能,调整碳密集产品出口份额;中国贸易伙伴格局或将重塑,向欧盟和美国的出口受冲击较大,RCEP和金砖国家对中国产品接纳能力提高,应按需调整贸易流动方向、优化产品圈层;CBAM对中国碳泄漏风险管控作用不大,需要构建更加完善的全生命周期隐含碳核算体系,推动碳市场不断完善。

Animal models of hepatitis E infection: Advances and challenges

Hepatitis E virus(HEV)is one of the leading causes of acute viral hepatitis worldwide.Although most of HEV infections are asymptomatic,some patients will develop the symptoms,especially pregnant women,the elderly,and patients with preexisting liver diseases,who often experience anorexia,nausea,vom-iting,malaise,abdominal pain,and jaundice.HEV infection may become chronic in immunosuppressed individuals.In addition,HEV infection can also cause several extrahepatic manifestations.HEV exists in a wide range of hosts in nature and can be transmitted across species.Hence,animals susceptible to HEV can be used as models.The establishment of animal models is of great significance for studying HEV transmission,clinical symptoms,extrahepatic manifestations,and therapeutic strategies,which will help us understand the pathogenesis,prevention,and treatment of hepatitis E.This review summarized the animal models of HEV,including pigs,monkeys,rabbits,mice,rats,and other animals.For each animal species,we provided a concise summary of the HEV genotypes that they can be infected with,the cross-species transmission pathways,as well as their role in studying extrahepatic manifestations,prevention,and treatment of HEV infection.The advantages and disadvantages of these animal models were also emphasized.This review offers new perspectives to enhance the current understanding of the research landscape surrounding HEV animal models.

Ecological Land Suitability for Arid Region at River Basin Scale:Framework and Application Based on Minmum Cumulative Resistance(MCR) Model

As an important and typical arid inland region in China,Shiyang River Basin plays an important role in maintaining the sustainable development of eco-environment,whose ecological land suitability restricts the development of the local human activities.Therefore,Shiyang River Basin was selected as the case study,the minimum cumulative resistance(MCR)model and GIS technique were integrated to create land suitability evaluation map.We calculated the MCR value of ecological source and living source,and divided the whole basin into five partitions according to the difference between ecological source and living source,and analyzed the patterns and characteristics of the ecological land suitability evaluation(ELSE)regions,respectively.The results showed that:1)The suitable ecological land includes prohibited development region and restricted development region,which accounts for 15.45%and 23.35%of the total land area of the Shiyang River Basin,respectively.These two regions mainly distributed high altitude region in the southern Qilian Mountain and low altitude region where had high density of rivers.2)The protection of ecological land requires not only conserving existing ecological land but also focusing on ecological buffer belts around ecological sources and improving ecological land service ability.3)Ecological networks should be constructed through artificial planting trees around the boundary of oasis and ecological restoration region.Buffer greenbelts should also be established between optimized development region and ecological restoration region.

Prediction model for hepatitis B e antigen seroconversion in chronic hepatitis B with peginterferon-alfa treated based on a responseguided therapy strategy

BACKGROUND Models for predicting hepatitis B e antigen(HBeAg)seroconversion in patients with HBeAg-positive chronic hepatitis B(CHB)after nucleos(t)ide analog treatment are rare.AIM To establish a simple scoring model based on a response-guided therapy(RGT)strategy for predicting HBeAg seroconversion and hepatitis B surface antigen(HBsAg)clearance.METHODS In this study,75 previously treated patients with HBeAg-positive CHB underwent a 52-week peginterferon-alfa(PEG-IFNα)treatment and a 24-wk follow-up.Logistic regression analysis was used to assess parameters at baseline,week 12,and week 24 to predict HBeAg seroconversion at 24 wk post-treatment.The two best predictors at each time point were used to establish a prediction model for PEG-IFNαtherapy efficacy.Parameters at each time point that met the corresponding optimal cutoff thresholds were scored as 1 or 0.RESULTS The two most meaningful predictors were HBsAg≤1000 IU/mL and HBeAg≤3 S/CO at baseline,HBsAg≤600 IU/mL and HBeAg≤3 S/CO at week 12,and HBsAg≤300 IU/mL and HBeAg≤2 S/CO at week 24.With a total score of 0 vs 2 at baseline,week 12,and week 24,the response rates were 23.8%,15.2%,and 11.1%vs 81.8%,80.0%,and 82.4%,respectively,and the HBsAg clearance rates were 2.4%,3.0%,and 0.0%,vs 54.5%,40.0%,and 41.2%,respectively.CONCLUSION We successfully established a predictive model and diagnosis-treatment process using the RGT strategy to predict HBeAg and HBsAg seroconversion in patients with HBeAg-positive CHB undergoing PEG-IFNαtherapy.

Security Vulnerability Analyses of Large Language Models (LLMs) through Extension of the Common Vulnerability Scoring System (CVSS) Framework

Large Language Models (LLMs) have revolutionized Generative Artificial Intelligence (GenAI) tasks, becoming an integral part of various applications in society, including text generation, translation, summarization, and more. However, their widespread usage emphasizes the critical need to enhance their security posture to ensure the integrity and reliability of their outputs and minimize harmful effects. Prompt injections and training data poisoning attacks are two of the most prominent vulnerabilities in LLMs, which could potentially lead to unpredictable and undesirable behaviors, such as biased outputs, misinformation propagation, and even malicious content generation. The Common Vulnerability Scoring System (CVSS) framework provides a standardized approach to capturing the principal characteristics of vulnerabilities, facilitating a deeper understanding of their severity within the security and AI communities. By extending the current CVSS framework, we generate scores for these vulnerabilities such that organizations can prioritize mitigation efforts, allocate resources effectively, and implement targeted security measures to defend against potential risks.

基于空间随机场理论的邓肯-张E-B模型参数敏感性研究

在土石坝工程中由于现场施工碾压的不确定性、料场取料的不均匀性导致坝料的力学参数在坝体空间上存在着变异性,这会使得采用确定参数的传统土石坝预测分析结果与坝体实际的应力变形性状存在差异。参考已建工程的坝料土工试验结果,引入空间随机场理论,通过构建平稳随机场进行坝体三维静力分析,获得了邓肯-张E-B模型各力学参数对坝体沉降及水平位移的影响状况,研究了邓肯-张E-B模型各力学参数的敏感性问题,并给出了敏感性排序结论。结果表明,邓肯-张E-B模型中参数K_(b)、K、φ_(0)对坝体变形的影响较大,其中以参数K_(b)的影响最为明显,参数n、R_(f)的影响次之,而参数Δφ、m较不敏感。研究结论可为土石坝坝体变形的合理预测和坝料特性研究提供参考。

A Generalized Gibbs Potential Model for Materials Degradation

It is well known that work done on a material by conservative forces (electrical, mechanical, chemical) will increase the Gibbs Potential of the material. The increase in Gibbs Potential can be stored in the material and is free/available to do work at some later time. However, it will be shown in this paper that while in this state of higher Gibbs potential, the material is metastable and the material will degrade spontaneously/naturally with time in an effort to reach a lower Gibbs Potential. A generalized Gibbs Potential Model is developed herein to better understand its impact on a materials degradation rate. Special attention will be given to dielectrics degradation.

Leaf Area Calculation Model of E.urophylla and E.grandis×E.urophylla

[Objective] The aim was to build an optimal leaf area measurement model of E. urophylla and E. grandis×E.urophylla. [Method] The correlation between leaf area and leaf＇s eigenvalue of E. urophylla and E. grandis×E.urophylla were studied. [Result] There was certain difference in leaf characteristics values between the 2 species. The leaf areas of E. urophylla and E. grandis×E.urophylla both had significant correlation with leaf length,leaf width,leaf perimeter,leaf length × leaf width,the ratio of leaf length to leaf width,shape factor,etc.,so the factors could be constructed into a regression model with leaf area. Among them,the best 2 models for leaf area calculation which were built by leaf length × leaf width of E. urophylla and E. grandis×E.urophylla both had relatively high accuracy and practical applications. [Conclusion] The research provides a simple and effective leaf area measurement method for studies on the 2 tree species.

基于E-Model的语音帧分组传输性能研究

voIP的语音帧分组大小是实时语音传输的关键参数。为提高网络效率和最大话路数,采用EModel的方法分析了RTP包中语音帧个数、语音长度、丢包概率和抖动缓冲区大小对语音质量的影响,给出了不同带宽时的最佳传输分组大小。仿真结果表明,在保证最基本的话音质量情况下,为不同链路确定合适的分组语音帧数能有效提高链路的最大话路数。

基于MSPA和MCR模型的庐山市生态网络构建

【目的】在生态环境形势严峻的背景下,构建生态网络是连接破碎化斑块间的重要纽带,是保障物种迁徙交流的有效途径。【方法】以庐山市为研究对象,以GIS技术为核心,利用MSPA法对庐山市进行景观格局分析,再运用景观连通性评价法选取重要生态源地;其次采用AHP分析法结合专家打分法建立阻力因子评价体系构建阻力面,再基于MCR模型完成庐山市生态网络的构建,运用重力模型选取重要潜在生态廊道,给出生态网络的优化对策,最后应用生态网络分析法,对出生态网络的可行性进行分析。【结果】1)庐山市10处重要生态源地的面积为37 946.52 hm^(2),庐山和鄱阳湖为两处大型生态源地;2)遴选出19条重要生态廊道长为297.05 km,主要分布于中部地区;3)构成生态廊道的景观三要素分别为林地、水系和耕地,廊道宽度设置为300 m;4)构建形成“两区两带三轴”的生态安全格局。【结论】研究区内中心城区及中南部地区斑块分布零碎,景观连通性差,缺少生物栖息活动的绿色空间,应大力改善两地的生态环境,生态绿廊由两地内部向外部空间延伸构建,最终绿廊绿道交织成网覆盖全域,新增3个生态核心节点和9条重要生态廊道后的网络连接指数明显提高,表明构建的庐山市生态网络可行性较强。研究结果对于庐山市的城市绿地系统规划、生态园林城市的建设和生物多样性保护具有一定的指导意义。

基于Model/View/Controller的电子商务研究

分析了传统电子商务系统的缺陷 ,电子商务发展趋势 ,分析了M/V/C(Model/View/Controller)技术 ,提出了基于M/V/C电子商务并且分析了其体系结构及框架结构 ,以及在此框架之上构建电子商务的方法。

基于SEM-ANN的数字人民币使用意愿影响因素研究

数字人民币是重塑我国支付新格局、加速数字经济进程的重要载体,但在用户推广方面仍存在诸多阻力,从用户的视角探究数字人民币使用意愿的影响因素具有重要的意义。本文以数字人民币为研究对象,在UTAUT2模型的基础上结合数字人民币的特点,构建数字人民币使用意愿理论模型;进而,以数字人民币首批试点城市的用户数据为样本,综合运用PLS-SEM和SEM-ANN方法实证分析数字人民币使用意愿的影响因素。结果表明,基于SEM的数字人民币使用意愿模型具有较好的解释和预测能力;信任、习惯、价格价值和社会影响对数字人民币使用意愿具有显著正向影响,而绩效期望、努力期望和创新意识对数字人民币使用意愿的影响不显著;此外,在作为调节变量的个人特征方面,价格价值与数字人民币使用意愿的关系受性别因素的调节;经验对价格价值、习惯、社会影响、信任与用户使用意愿的关系均具有调节作用;将结构方程模型与人工神经网络相结合能够提升模型的预测精度,并且影响因素的重要性有所改变,习惯最为重要、信任次之,其次为社会影响和价格价值。

基于MCR-InVEST模型的城郊耕地多功能评价及功能分区

城郊地区作为城乡融合区域,展现出既不同于城市建成区又异于传统乡村的特征,显化城郊地区耕地资源多功能的空间分异特征对于提高城郊地区耕地资源价值,推动耕地的保护与发展具有重要意义。该研究以南昌市城郊作为研究区,全国第三次国土调查耕地图斑及乡镇为基本研究单元,进行实地土壤采样与调研,基于多源数据使用综合指数法、MCR模型、InVEST模型量化耕地的多功能,分析耕地多功能空间差异并根据区域差异进行耕地多功能分区。结果表明:1)南昌市城郊耕地生产功能等级较高,中高等级耕地面积为16358.31 hm2,占比78%,主要位于东湖区、青山湖区、湾里管理局;文化景观功能等级高,耕地处于中高等的面积为15295.73 hm2,占比73%,高等级区域位于东湖区以及高新区麻丘镇;大部分耕地的生态功能处于中等,为11010.19 hm2,占比52%,高等级区域主要位于湾里管理局。2)根据耕地多功能分区理论框架和乡镇耕地多功能结果识别出6个功能一级分区,11个二级分区。南昌市城郊不同区域耕地的多功能具有不同的差异与特征,要根据区域耕地功能特色采取差异化的耕地利用、发展与保护策略。研究结果可为科学规划城郊耕地功能、优化空间布局促进耕地多功能综合发展提供依据。

基于ANSYS Electronics Desktop/Maxwell3D的MCR-WPT系统仿真

基于对磁共振无线电能传输(MCR-WPT)原理的推导与分析,采用ANSYS Electronics Desktop/Maxwell3D对经典S/S补偿模型MCR-WPT系统进行模拟仿真,观察系统的能量交换和磁场分布情况。所搭建实际模型与模拟仿真结果比较一致,表明系统的整体硬件电路能够进行正常的电能无线传输;传输特性的实验结果与理论分析结果也比较吻合,证实了系统的可行性与实用性。

RCEP协定下跨境电商对贸易影响的时间差异性研究

为了拓宽双循环渠道,打开外循环新思路,以中国与RCEP成员国在2010年至2021年间进出口面板数据结合中国跨境电商交易额建立VAR模型,研究跨境电子商务发展对我国进出口贸易的动态影响。结果表明,在长期,跨境电商的发展使得发展中国家与我国双边贸易弹性系数高于发达国家,跨境电商的发展有利于我国同发展中国家进行贸易往来;在短期,跨境电商的发展对中国与韩国等部分国家的进出口存在逐渐增强的正向影响;跨境电商的发展对我国与多国贸易存在双向动态交互关系。

基于ADDIE模型的沉浸式电子商务教学实践探索

我国电子商务行业方兴未艾,其专业人才的需求旺盛,因而许多高职院校都开设有电子商务专业。但与此同时,高职电子商务专业的毕业生往往就业率偏低且专业不对口的问题一直存在。不少民营企业来校园招聘电子商务人才往往找不到匹配工作岗位的人才。本文分析了造成这样问题的原因,并提出了通过ADDIE模型进行沉浸式教学设计的应对措施。

引入包分析的E-Model语音质量评价模型改进

为了能够更加准确地评价语音包丢失对基于IP的语音传输(voice over internet protocol,Vo IP)的语音质量的损伤,对ITU-T G.107建议书提出的语音质量预测模型E-Model中计算丢包与编码造成的损伤Ie-eff的方法作出改进,在综合考虑语音包的内部特性和存在突发连续丢包情况后,提出利用在固定语音长度下,语音实际损失时间Tloss来衡量语音包丢失造成的语音损伤。仿真结果表明,相比原有模型,改进后的模型得到的语音质量评分同主观语音质量评估方法(perceptual evaluation of speech quality,PESQ)评分相比,皮尔森相关系数平均提高了0.045 8,均方根误差平均降低了0.053 4,改进后的E-Model模型在评价语音质量时与PESQ更具有一致性,可以更为准确地预测Vo IP通信的语音质量。