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BLUE-plus方案的肺超声评分在急性呼吸衰竭患者胸部物理治疗中的应用
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作者 陈春艳 张艳阳 王柱 《湖北理工学院学报》 2024年第5期63-68,共6页
为了探究BLUE-plus方案的肺超声评分引导胸部物理治疗(CPT)在急性呼吸衰竭患者氧合能力、感染指标和肺通气功能方面的效果,根据样本量估算招募急性呼吸衰竭患者102例,随机分为试验组和对照组。试验组根据BLUE-plus肺超声征象、肺超声评... 为了探究BLUE-plus方案的肺超声评分引导胸部物理治疗(CPT)在急性呼吸衰竭患者氧合能力、感染指标和肺通气功能方面的效果,根据样本量估算招募急性呼吸衰竭患者102例,随机分为试验组和对照组。试验组根据BLUE-plus肺超声征象、肺超声评分实施精准CPT,对照组采用常规CPT。比较两组患者入ICU第1~5天的氧合指数和第1、5天的血感染指标(降钙素原(PCT)、白介素-6(IL-6))及肺部超声评分、机械通气时长和ICU住院时长,发现BLUE-plus方案的肺超声评分指导的CPT可以改善急性呼吸衰竭患者的氧合指数、感染指标(IL-6)、肺部情况,缩短机械通气的时间。相较于对照组,试验组在第3~5天的氧合指数具有统计学差异(P<0.05),第5天IL-6、肺部超声评分、机械通气时长差异具有统计学意义(P<0.05),PCT、ICU住院时长无统计学差异(P>0.05)。 展开更多
关键词 blue-plus肺超声引导 急性呼吸衰竭 胸部物理治疗 氧合指数 肺超声评分
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肺部超声BLUE-plus方案对急性呼吸衰竭病因诊断的价值 被引量:2
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作者 刘璇 方丽 林凤 《当代医学》 2021年第19期84-87,共4页
目的探讨肺部超声BLUE-plus(bedside lungultrasoundinemergency-PLUS)方案对急性呼吸衰竭病因诊断的价值。方法选取2018年11月至2020年8月贵阳市第一人民医院重症医学科收治的急性呼吸衰竭患者61例作为研究对象。探讨应用BLUE-plus方... 目的探讨肺部超声BLUE-plus(bedside lungultrasoundinemergency-PLUS)方案对急性呼吸衰竭病因诊断的价值。方法选取2018年11月至2020年8月贵阳市第一人民医院重症医学科收治的急性呼吸衰竭患者61例作为研究对象。探讨应用BLUE-plus方案筛查呼吸衰竭病因的准确性。结果BLUE-plus方案对胸腔积液敏感性为97.6%,特异性为100.0%,阳性预期值为100.0%,阴性预期值为95.0%;BLUE-plus方案对肺实变/肺不张的敏感性为89.3%,特异性为97.0%,阳性预期值为96.2%,阴性预期值为91.4%。床旁胸片对胸腔积液敏感性为85.6%,特异性为94.7%,阳性预期值为97.3%,阴性预期值为75.0%;床旁胸片对肺实变/肺不张的敏感性为78.6%,特异性为94.0%,阳性预期值为83.8%,阴性预期值为86.9%。肺部超声对胸腔积液诊断的正确率及敏感性高于床旁胸片,差异有统计学意义(P<0.05)。结论肺部超声BLUE-plus是急性呼吸衰竭病因诊断的快速有效方法,尤其对胸腔积液诊断的敏感性及正确率均高于床旁胸片。 展开更多
关键词 肺部超声 blue-plus方案 急性呼吸衰竭
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基于BLUE-plus方案的肺部超声联合床旁胸片在评估重症患者肺部病变中的临床应用
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作者 龚良国 柏园 +3 位作者 余鹏 龚毅 陈媛慧 万建国 《江西医药》 CAS 2023年第12期1402-1405,共4页
目的探讨联合肺部超声和床旁胸片在评估重症患者肺部病变中的作用。方法选取2021年1月至2022年8月入住ICU的重症患者52例,所有患者入院后完善BLUE-plus方案的床旁超声检查以及床旁胸片检查,24小时内完善胸部CT检查。记录床旁超声及床旁... 目的探讨联合肺部超声和床旁胸片在评估重症患者肺部病变中的作用。方法选取2021年1月至2022年8月入住ICU的重症患者52例,所有患者入院后完善BLUE-plus方案的床旁超声检查以及床旁胸片检查,24小时内完善胸部CT检查。记录床旁超声及床旁胸片的结果,判断患者肺水增加改变、肺实变、胸腔积液、气胸的发生及部位,与患者的胸部CT相比较,分析联合肺部超声与床旁胸片检查对肺部各种病变诊断的敏感性与特异性。结果以胸部CT诊断作为金标准,联合诊断法胸腔积液、肺实变、肺炎的诊断正确率分别为96.15%、94.23%、92.31%;相较床旁超声对胸腔积液(80.77%)、肺炎(73.08%)及床旁胸片对胸腔积液(76.92%)、肺实变/肺不张(69.23%)差异有统计学意义。联合诊断在对气胸的诊断上与其他两组诊断方法相比较差异无统计学意义。结论床旁超声检查联合床旁胸片检查可提供可靠的重症患者肺部病变诊断。 展开更多
关键词 肺部超声 blue-plus方案 床旁胸片 重症患者 肺部疾病
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Construction of a Computational Scheme for the Fuzzy HIV/AIDS Epidemic Model with a Nonlinear Saturated Incidence Rate 被引量:1
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作者 Muhammad Shoaib Arif Kamaleldin Abodayeh Yasir Nawaz 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第2期1405-1425,共21页
This work aimed to construct an epidemic model with fuzzy parameters.Since the classical epidemic model doesnot elaborate on the successful interaction of susceptible and infective people,the constructed fuzzy epidemi... This work aimed to construct an epidemic model with fuzzy parameters.Since the classical epidemic model doesnot elaborate on the successful interaction of susceptible and infective people,the constructed fuzzy epidemicmodel discusses the more detailed versions of the interactions between infective and susceptible people.Thenext-generation matrix approach is employed to find the reproduction number of a deterministic model.Thesensitivity analysis and local stability analysis of the systemare also provided.For solving the fuzzy epidemic model,a numerical scheme is constructed which consists of three time levels.The numerical scheme has an advantage overthe existing forward Euler scheme for determining the conditions of getting the positive solution.The establishedscheme also has an advantage over existing non-standard finite difference methods in terms of order of accuracy.The stability of the scheme for the considered fuzzy model is also provided.From the plotted results,it can beobserved that susceptible people decay by rising interaction parameters. 展开更多
关键词 Epidemic model fuzzy rate parameters next generation matrix local stability proposed numerical scheme
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On the Use of Monotonicity-Preserving Interpolatory Techniques in Multilevel Schemes for Balance Laws
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作者 Antonio Baeza Rosa Donat Anna Martinez-Gavara 《Communications on Applied Mathematics and Computation》 EI 2024年第2期1319-1341,共23页
Cost-effective multilevel techniques for homogeneous hyperbolic conservation laws are very successful in reducing the computational cost associated to high resolution shock capturing numerical schemes.Because they do ... Cost-effective multilevel techniques for homogeneous hyperbolic conservation laws are very successful in reducing the computational cost associated to high resolution shock capturing numerical schemes.Because they do not involve any special data structure,and do not induce savings in memory requirements,they are easily implemented on existing codes and are recommended for 1D and 2D simulations when intensive testing is required.The multilevel technique can also be applied to balance laws,but in this case,numerical errors may be induced by the technique.We present a series of numerical tests that point out that the use of monotonicity-preserving interpolatory techniques eliminates the numerical errors observed when using the usual 4-point centered Lagrange interpolation,and leads to a more robust multilevel code for balance laws,while maintaining the efficiency rates observed forhyperbolic conservation laws. 展开更多
关键词 Hyperbolic balance laws Well-balanced schemes Multilevel schemes Harten's multiresolution
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An Arbitrarily High Order and Asymptotic Preserving Kinetic Scheme in Compressible Fluid Dynamic
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作者 Remi Abgrall Fatemeh Nassajian Mojarrad 《Communications on Applied Mathematics and Computation》 EI 2024年第2期963-991,共29页
We present a class of arbitrarily high order fully explicit kinetic numerical methods in compressible fluid dynamics,both in time and space,which include the relaxation schemes by Jin and Xin.These methods can use the... We present a class of arbitrarily high order fully explicit kinetic numerical methods in compressible fluid dynamics,both in time and space,which include the relaxation schemes by Jin and Xin.These methods can use the CFL number larger or equal to unity on regular Cartesian meshes for the multi-dimensional case.These kinetic models depend on a small parameter that can be seen as a"Knudsen"number.The method is asymptotic preserving in this Knudsen number.Also,the computational costs of the method are of the same order of a fully explicit scheme.This work is the extension of Abgrall et al.(2022)[3]to multidimensional systems.We have assessed our method on several problems for two-dimensional scalar problems and Euler equations and the scheme has proven to be robust and to achieve the theoretically predicted high order of accuracy on smooth solutions. 展开更多
关键词 Kinetic scheme Compressible fluid dynamics High order methods Explicit schemes Asymptotic preserving Defect correction method
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S-scheme heterojunction with ultrafast interfacial electron transfer for artificial photosynthesis
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作者 Sihang Mao Rongan He Shaoqing Song 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第9期1-3,共3页
The rapid development of the global economy has led to the over-exploitation and burning of fossil fuels,causing a severe energy crisis and continuous CO_(2) emissions.Although solar energy is a clean and renewable re... The rapid development of the global economy has led to the over-exploitation and burning of fossil fuels,causing a severe energy crisis and continuous CO_(2) emissions.Although solar energy is a clean and renewable resource,it faces significant diurnal and seasonal variations and is difficult to store[1-4].Converting solar energy into storable chemical energy through photocatalysis is an effective way to address both energy scarcity and environmental issues.Photocatalytic CO_(2) reduction,with the development of high-efficiency photocatalysts as the key,offers a clean and environmentally friendly method to convert CO_(2) into valuable hydrocarbon fuels,providing a viable solution to the global energy crisis and climate change[5,6]. 展开更多
关键词 CONVERT STORE scheme
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Orbit Weighting Scheme in the Context of Vector Space Information Retrieval
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作者 Ahmad Ababneh Yousef Sanjalawe +2 位作者 Salam Fraihat Salam Al-E’mari Hamzah Alqudah 《Computers, Materials & Continua》 SCIE EI 2024年第7期1347-1379,共33页
This study introduces the Orbit Weighting Scheme(OWS),a novel approach aimed at enhancing the precision and efficiency of Vector Space information retrieval(IR)models,which have traditionally relied on weighting schem... This study introduces the Orbit Weighting Scheme(OWS),a novel approach aimed at enhancing the precision and efficiency of Vector Space information retrieval(IR)models,which have traditionally relied on weighting schemes like tf-idf and BM25.These conventional methods often struggle with accurately capturing document relevance,leading to inefficiencies in both retrieval performance and index size management.OWS proposes a dynamic weighting mechanism that evaluates the significance of terms based on their orbital position within the vector space,emphasizing term relationships and distribution patterns overlooked by existing models.Our research focuses on evaluating OWS’s impact on model accuracy using Information Retrieval metrics like Recall,Precision,InterpolatedAverage Precision(IAP),andMeanAverage Precision(MAP).Additionally,we assessOWS’s effectiveness in reducing the inverted index size,crucial for model efficiency.We compare OWS-based retrieval models against others using different schemes,including tf-idf variations and BM25Delta.Results reveal OWS’s superiority,achieving a 54%Recall and 81%MAP,and a notable 38%reduction in the inverted index size.This highlights OWS’s potential in optimizing retrieval processes and underscores the need for further research in this underrepresented area to fully leverage OWS’s capabilities in information retrieval methodologies. 展开更多
关键词 Information retrieval orbit weighting scheme semantic text analysis Tf-Idf weighting scheme vector space model
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Analysis and Comparison of Slope-cutting Widening Schemes in Highway Reconstruction and Expansion Project Based on MIDAS Software 被引量:1
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作者 Zhiqiang Qiu Yun Shi Lei Jiang 《Journal of Architectural Research and Development》 2024年第2期75-83,共9页
In this paper,the geological condition of the right-side slope of the K114+694–K115+162 section of Yong-tai-wen Expressway is investigated and analyzed with the results showing that the strength of rock mass is the m... In this paper,the geological condition of the right-side slope of the K114+694–K115+162 section of Yong-tai-wen Expressway is investigated and analyzed with the results showing that the strength of rock mass is the main contributor to the stability of the slope.Then,two widening schemes are proposed,which are the steep slope with strong support and the gentle slope with general support schemes.The static/slope module of MIDAS GTS finite element analysis software and the strength reduction method were used to compare the two schemes.The results show that the steep slope with a strong support scheme has obvious advantages in land requisition,environmental protection,and safety and is more suitable for reconstructing and expanding the highway slope. 展开更多
关键词 Highway reconstruction and expansion Slope excavation MIDAS GTS scheme selection
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Deployment Dynamic Modeling and Driving Schemes for a Ring-Truss Deployable Antenna
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作者 Baiyan He Lijun Jia +3 位作者 Kangkang Li Rui Nie Yesen Fan Guobiao Wang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2024年第4期163-182,共20页
Mesh reflector antennas are widely used in space tasks owing to their light weight,high surface accuracy,and large folding ratio.They are stowed during launch and then fully deployed in orbit to form a mesh reflector ... Mesh reflector antennas are widely used in space tasks owing to their light weight,high surface accuracy,and large folding ratio.They are stowed during launch and then fully deployed in orbit to form a mesh reflector that transmits signals.Smooth deployment is essential for duty services;therefore,accurate and efficient dynamic modeling and analysis of the deployment process are essential.One major challenge is depicting time-varying resistance of the cable network and capturing the cable-truss coupling behavior during the deployment process.This paper proposes a general dynamic analysis methodology for cable-truss coupling.Considering the topological diversity and geometric nonlinearity,the cable network's equilibrium equation is derived,and an explicit expression of the time-varying tension of the boundary cables,which provides the main resistance in truss deployment,is obtained.The deployment dynamic model is established,which considers the coupling effect between the soft cables and deployable truss.The effects of the antenna's driving modes and parameters on the dynamic deployment performance were investigated.A scaled prototype was manufactured,and the deployment experiment was conducted to verify the accuracy of the proposed modeling method.The proposed methodology is suitable for general cable antennas with arbitrary topologies and parameters,providing theoretical guidance for the dynamic performance evaluation of antenna driving schemes. 展开更多
关键词 Cable antenna Deployment dynamics Performance evaluation Driving scheme Deployable structure
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Improvement and security analysis of multi-ring discrete modulation continuous variable quantum secret sharing scheme
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作者 姜欢窈 聂敏 +3 位作者 杨光 孙爱晶 张美玲 裴昌幸 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第7期189-197,共9页
In order to avoid the complexity of Gaussian modulation and the problem that the traditional point-to-point communication DM-CVQKD protocol cannot meet the demand for multi-user key sharing at the same time, we propos... In order to avoid the complexity of Gaussian modulation and the problem that the traditional point-to-point communication DM-CVQKD protocol cannot meet the demand for multi-user key sharing at the same time, we propose a multi-ring discrete modulation continuous variable quantum key sharing scheme(MR-DM-CVQSS). In this paper, we primarily compare single-ring and multi-ring M-symbol amplitude and phase-shift keying modulations. We analyze their asymptotic key rates against collective attacks and consider the security key rates under finite-size effects. Leveraging the characteristics of discrete modulation, we improve the quantum secret sharing scheme. Non-dealer participants only require simple phase shifters to complete quantum secret sharing. We also provide the general design of the MR-DM-CVQSS protocol.We conduct a comprehensive analysis of the improved protocol's performance, confirming that the enhancement through multi-ring M-PSK allows for longer-distance quantum key distribution. Additionally, it reduces the deployment complexity of the system, thereby increasing the practical value. 展开更多
关键词 discrete modulation continuous variable quantum secret sharing scheme
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A Non-Parametric Scheme for Identifying Data Characteristic Based on Curve Similarity Matching
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作者 Quanbo Ge Yang Cheng +3 位作者 Hong Li Ziyi Ye Yi Zhu Gang Yao 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第6期1424-1437,共14页
For accurately identifying the distribution charac-teristic of Gaussian-like noises in unmanned aerial vehicle(UAV)state estimation,this paper proposes a non-parametric scheme based on curve similarity matching.In the... For accurately identifying the distribution charac-teristic of Gaussian-like noises in unmanned aerial vehicle(UAV)state estimation,this paper proposes a non-parametric scheme based on curve similarity matching.In the framework of the pro-posed scheme,a Parzen window(kernel density estimation,KDE)method on sliding window technology is applied for roughly esti-mating the sample probability density,a precise data probability density function(PDF)model is constructed with the least square method on K-fold cross validation,and the testing result based on evaluation method is obtained based on some data characteristic analyses of curve shape,abruptness and symmetry.Some com-parison simulations with classical methods and UAV flight exper-iment shows that the proposed scheme has higher recognition accuracy than classical methods for some kinds of Gaussian-like data,which provides better reference for the design of Kalman filter(KF)in complex water environment. 展开更多
关键词 Curve similarity matching Gaussian-like noise non-parametric scheme parzen window.
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A Neural-network-based Alternative Scheme to Include Nonhydrostatic Processes in an Atmospheric Dynamical Core
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作者 Yang XIA Bin WANG +13 位作者 Lijuan LI Li LIU Jianghao LI Li DONG Shiming XU Yiyuan LI Wenwen XIA Wenyu HUANG Juanjuan LIU Yong WANG Hongbo LIU Ye PU Yujun HE Kun XIA 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第6期1083-1099,I0002,I0003,共19页
Here,a nonhydrostatic alternative scheme(NAS)is proposed for the grey zone where the nonhydrostatic impact on the atmosphere is evident but not large enough to justify the necessity to include an implicit nonhydrostat... Here,a nonhydrostatic alternative scheme(NAS)is proposed for the grey zone where the nonhydrostatic impact on the atmosphere is evident but not large enough to justify the necessity to include an implicit nonhydrostatic solver in an atmospheric dynamical core.The NAS is designed to replace this solver,which can be incorporated into any hydrostatic models so that existing well-developed hydrostatic models can effectively serve for a longer time.Recent advances in machine learning(ML)provide a potential tool for capturing the main complicated nonlinear-nonhydrostatic relationship.In this study,an ML approach called a neural network(NN)was adopted to select leading input features and develop the NAS.The NNs were trained and evaluated with 12-day simulation results of dry baroclinic-wave tests by the Weather Research and Forecasting(WRF)model.The forward time difference of the nonhydrostatic tendency was used as the target variable,and the five selected features were the nonhydrostatic tendency at the last time step,and four hydrostatic variables at the current step including geopotential height,pressure in two different forms,and potential temperature,respectively.Finally,a practical NAS was developed with these features and trained layer by layer at a 20-km horizontal resolution,which can accurately reproduce the temporal variation and vertical distribution of the nonhydrostatic tendency.Corrected by the NN-based NAS,the improved hydrostatic solver at different horizontal resolutions can run stably for at least one month and effectively reduce most of the nonhydrostatic errors in terms of system bias,anomaly root-mean-square error,and the error of the wave spatial pattern,which proves the feasibility and superiority of this scheme. 展开更多
关键词 neural network nonhydrostatic alternative scheme atmospheric model dynamical core
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Verifiable quantum secret sharing scheme based on orthogonal product states
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作者 白晨明 刘璐 张素娟 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第7期178-187,共10页
In the domain of quantum cryptography,the implementation of quantum secret sharing stands as a pivotal element.In this paper,we propose a novel verifiable quantum secret sharing protocol using the d-dimensional produc... In the domain of quantum cryptography,the implementation of quantum secret sharing stands as a pivotal element.In this paper,we propose a novel verifiable quantum secret sharing protocol using the d-dimensional product state and Lagrange interpolation techniques.This protocol is initiated by the dealer Alice,who initially prepares a quantum product state,selected from a predefined set of orthogonal product states within the C~d■C~d framework.Subsequently,the participants execute unitary operations on this product state to recover the underlying secret.Furthermore,we subject the protocol to a rigorous security analysis,considering both eavesdropping attacks and potential dishonesty from the participants.Finally,we conduct a comparative analysis of our protocol against existing schemes.Our scheme exhibits economies of scale by exclusively employing quantum product states,thereby realizing significant cost-efficiency advantages.In terms of access structure,we adopt a(t, n)-threshold architecture,a strategic choice that augments the protocol's practicality and suitability for diverse applications.Furthermore,our protocol includes a rigorous integrity verification mechanism to ensure the honesty and reliability of the participants throughout the execution of the protocol. 展开更多
关键词 quantum secret sharing quantum product state threshold scheme unitary operations
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Quantum-Resistant Multi-Feature Attribute-Based Proxy Re-Encryption Scheme for Cloud Services
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作者 Jinqiu Hou Changgen Peng +1 位作者 Weijie Tan Hongfa Ding 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第1期917-938,共22页
Cloud-based services have powerful storage functions and can provide accurate computation.However,the question of how to guarantee cloud-based services access control and achieve data sharing security has always been ... Cloud-based services have powerful storage functions and can provide accurate computation.However,the question of how to guarantee cloud-based services access control and achieve data sharing security has always been a research highlight.Although the attribute-based proxy re-encryption(ABPRE)schemes based on number theory can solve this problem,it is still difficult to resist quantum attacks and have limited expression capabilities.To address these issues,we present a novel linear secret sharing schemes(LSSS)matrix-based ABPRE scheme with the fine-grained policy on the lattice in the research.Additionally,to detect the activities of illegal proxies,homomorphic signature(HS)technology is introduced to realize the verifiability of re-encryption.Moreover,the non-interactivity,unidirectionality,proxy transparency,multi-use,and anti-quantum attack characteristics of our system are all advantageous.Besides,it can efficiently prevent the loss of processing power brought on by repetitive authorisation and can enable precise and safe data sharing in the cloud.Furthermore,under the standard model,the proposed learning with errors(LWE)-based scheme was proven to be IND-sCPA secure. 展开更多
关键词 LATTICE learning with errors attribute-based proxy re-encryption linear secret sharing schemes
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A MOVING WATER EQUILIBRIA PRESERVING NONSTAGGERED CENTRAL SCHEME ACHIEVED VIA FLUX GLOBALIZATION FOR THE RIPA MODEL
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作者 Zhen LI Min LIU Dingfang LI 《Acta Mathematica Scientia》 SCIE CSCD 2024年第6期2307-2340,共34页
In this paper,we propose a second-order moving-water equilibria preserving nonstaggered central scheme to solve the Ripa model via flux globalization.To maintain the moving-water steady states,we use the discrete sour... In this paper,we propose a second-order moving-water equilibria preserving nonstaggered central scheme to solve the Ripa model via flux globalization.To maintain the moving-water steady states,we use the discrete source terms proposed by Britton et al.(J Sci Comput,2020,82(2):Art 30)by incorporating the expression of the source terms as a whole into the flux gradient,which directly avoids the discrete complexity of the source terms in order to maintain the well-balanced properties of the scheme.In addition,since the nonstaggered central scheme requires re-projecting the updated values of the nonstaggered cells onto the staggered cells,we modify the calculation of the global variables by constructing ghost cells and alternating the values of the global variables with the water depths obtained from the solution through the nonlinear relationship between the global flux and the water depth.In order to maintain the second-order accuracy of the scheme on the time scale,we incorporate a new Runge-Kutta type time discretization in the evolution of the numerical solution for the nonstaggered cells.Meanwhile,we introduce the"draining"time step technique to ensure that the water depth is positive and that it satisfies mass conservation.Numerical experiments verify that the scheme is well-balanced,positivity-preserving and robust. 展开更多
关键词 Ripa model moving-water steady states nonstaggered central scheme flux globalization Runge-Kutta solvers
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A Practical Regular LDPC Coded Scheme for Physical-Layer Information Security
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作者 Du Junyi 《China Communications》 SCIE CSCD 2024年第5期190-201,共12页
In this paper,we aim to design a practical low complexity low-density parity-check(LDPC)coded scheme to build a secure open channel and protect information from eavesdropping.To this end,we first propose a punctured L... In this paper,we aim to design a practical low complexity low-density parity-check(LDPC)coded scheme to build a secure open channel and protect information from eavesdropping.To this end,we first propose a punctured LDPC coded scheme,where the information bits in a codeword are punctured and only the parity check bits are transmitted to the receiver.We further propose a notion of check node type distribution and derive multi-edge type extrinsic information transfer functions to estimate the security performance,instead of the well-known weak metric bit error rate.We optimize the check node type distribution in terms of the signal-to-noise ratio(SNR)gap and modify the progressive edge growth algorithm to design finite-length codes.Numerical results show that our proposed scheme can achieve a lower computational complexity and a smaller security gap,compared to the existing scrambling and puncturing schemes. 展开更多
关键词 extrinsic information transfer function physical layer scheme secure open channel security gap
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A hybrid ventilation scheme applied to bidirectional excavation tunnel construction with a long inclined shaft
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作者 YANG Wei-chao WANG Jian +3 位作者 DENG E LIU Yi-kang LUO Lu-sen YANG Jia 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第9期3187-3205,共19页
The breakage and bending of ducts result in a difficulty to cope with ventilation issues in bidirectional excavation tunnels with a long inclined shaft using a single ventilation method based on ducts.To discuss the h... The breakage and bending of ducts result in a difficulty to cope with ventilation issues in bidirectional excavation tunnels with a long inclined shaft using a single ventilation method based on ducts.To discuss the hybrid ventilation system applied in bidirectional excavation tunnels with a long inclined shaft,this study has established a full-scale computational fluid dynamics model based on field tests,the Poly-Hexcore method,and the sliding mesh technique.The distribution of wind speed,temperature field,and CO in the tunnel are taken as indices to compare the ventilation efficiency of three ventilation systems(duct,duct-ventilation shaft,duct–ventilated shaft-axial fan).The results show that the hybrid ventilation scheme based on duct-ventilation shaft–axial fan performs the best among the three ventilation systems.Compared to the duct,the wind speed and cooling rate in the tunnel are enhanced by 7.5%–30.6%and 14.1%–17.7%,respectively,for the duct-vent shaft-axial fan condition,and the volume fractions of CO are reduced by 26.9%–73.9%.This contributes to the effective design of combined ventilation for bidirectional excavation tunnels with an inclined shaft,ultimately improving the air quality within the tunnel. 展开更多
关键词 bidirectional excavation tunnel inclined shaft hybrid ventilation scheme computational fluid dynamics ventilation efficiency
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Efficient Finite Difference WENO Scheme for Hyperbolic Systems withNon-conservativeProducts
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作者 Dinshaw S.Balsara Deepak Bhoriya +1 位作者 Chi-Wang Shu Harish Kumar 《Communications on Applied Mathematics and Computation》 EI 2024年第2期907-962,共56页
Higher order finite difference weighted essentially non-oscillatory(WENO)schemes have been constructed for conservation laws.For multidimensional problems,they offer a high order accuracy at a fraction of the cost of ... Higher order finite difference weighted essentially non-oscillatory(WENO)schemes have been constructed for conservation laws.For multidimensional problems,they offer a high order accuracy at a fraction of the cost of a finite volume WENO or DG scheme of the comparable accuracy.This makes them quite attractive for several science and engineering applications.But,to the best of our knowledge,such schemes have not been extended to non-linear hyperbolic systems with non-conservative products.In this paper,we perform such an extension which improves the domain of the applicability of such schemes.The extension is carried out by writing the scheme in fluctuation form.We use the HLLI Riemann solver of Dumbser and Balsara(J.Comput.Phys.304:275-319,2016)as a building block for carrying out this extension.Because of the use of an HLL building block,the resulting scheme has a proper supersonic limit.The use of anti-diffusive fluxes ensures that stationary discontinuities can be preserved by the scheme,thus expanding its domain of the applicability.Our new finite difference WENO formulation uses the same WENO reconstruction that was used in classical versions,making it very easy for users to transition over to the present formulation.For conservation laws,the new finite difference WENO is shown to perform as well as the classical version of finite difference WENO,with two major advantages:(i)It can capture jumps in stationary linearly degenerate wave families exactly.(i)It only requires the reconstruction to be applied once.Several examples from hyperbolic PDE systems with non-conservative products are shown which indicate that the scheme works and achieves its design order of the accuracy for smooth multidimensional flows.Stringent Riemann problems and several novel multidimensional problems that are drawn from compressible Baer-Nunziato multiphase flow,multiphase debris flow and twolayer shallow water equations are also shown to document the robustness of the method.For some test problems that require well-balancing we have even been able to apply the scheme without any modification and obtain good results.Many useful PDEs may have stiff relaxation source terms for which the finite difference formulation of WENO is shown to provide some genuine advantages. 展开更多
关键词 Hyperbolic PDEs Numerical schemes Non-conservative products Stiff source terms Finite difference WENO
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Revisting High-Resolution Schemes with van Albada Slope Limiter
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作者 Jingcheng Lu Eitan Tadmor 《Communications on Applied Mathematics and Computation》 EI 2024年第3期1924-1953,共30页
Slope limiters play an essential role in maintaining the non-oscillatory behavior of high-resolution methods for nonlinear conservation laws.The family of minmod limiters serves as the prototype example.Here,we revisi... Slope limiters play an essential role in maintaining the non-oscillatory behavior of high-resolution methods for nonlinear conservation laws.The family of minmod limiters serves as the prototype example.Here,we revisit the question of non-oscillatory behavior of high-resolution central schemes in terms of the slope limiter proposed by van Albada et al.(Astron Astrophys 108:76–84,1982).The van Albada(vA)limiter is smoother near extrema,and consequently,in many cases,it outperforms the results obtained using the standard minmod limiter.In particular,we prove that the vA limiter ensures the one-dimensional Total-Variation Diminishing(TVD)stability and demonstrate that it yields noticeable improvement in computation of one-and two-dimensional systems. 展开更多
关键词 High resolution LIMITERS Total-Variation Diminishing(TVD)stability Central schemes
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