检索结果-南通市图书馆

Topic Modelling and Sentimental Analysis of Students’Reviews

Computers, Materials & Continua 2023年第3期74卷 6835-6848页

作者： Omer S.Alkhnbashi rasheed Mohammad Nassr Information and Computer Science Department King Fahd University of Petroleum and Minerals31261Kingdom Saudi Arabia Computer Science Department School of Computing and Digital TechnologyBirmingham City UniversityBirminghamB55JUUnited Kingdom

Globally,educational institutions have reported a dramatic shift to online learning in an effort to contain the COVID-19 *** fundamental concern has been the continuance of *** a result,several novel solutions have been developed to address technical and pedagogical ***,these were not the only difficulties that students *** implemented solutions involved the operation of the educational process with less regard for students’changing circumstances,which obliged them to study from *** should be asked to provide a full list of their *** a result,student reflections,including those from Saudi Arabia,have been analysed to identify obstacles encountered during the COVID-19 ***,most of the analyses relied on closed-ended questions,which limited student *** delve into students’responses,this study used open-ended questions,a qualitative method(content analysis),a quantitative method(topic modelling),and a sentimental *** study also looked at students’emotional states during and after the COVID-19 *** terms of determining trends in students’input,the results showed that quantitative and qualitative methods produced similar *** had unfavourable sentiments about studying during COVID-19 and positive sentiments about the face-to-face ***,topic modelling has revealed that the majority of difficulties are more related to the environment(home)and social *** were less accepting of online *** a result,it is possible to conclude that face-to-face study still attracts students and provides benefits that online study cannot,such as social interaction and effective eye-to-eye communication.

关键词： Topic modelling sentimental analysis COVID-19 students’input

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A Novel Modified Alpha Power Transformed Weibull Distribution and Its Engineering Applications

引用

Computer Modeling in Engineering & Sciences 2023年第6期135卷 2065-2089页

作者： Refah Alotaibi Hassan Okasha mazen Nassar Ahmed Elshahhat Department of Mathematical Sciences College of SciencePrincess Nourah bint Abdulrahman UniversityP.O.Box 84428Riyadh11671Saudi Arabia Department of Statistics Faculty of ScienceKing Abdulaziz UniversityJeddah80200Saudi Arabia Department of Mathematics Faculty of ScienceAl-Azhar UniversityNasr CityCairo11884Egypt Department of Statistics Faculty of CommerceZagazig UniversityZagazig44519Egypt Faculty of Technology and Development Zagazig UniversityZagazig44519Egypt

This paper suggests a new modified version of the traditional Weibull distribution by adding a new shape parameter utilising the modified alpha power transformed *** refer to the new model as modified alpha power transformed Weibull *** attractiveness and significance of the new distribution lie in its power to model monotone and non-monotone failure rate functions,which are quite familiar in environmental *** hazard rate function can be decreasing,increasing,bathtub and upside-down then bathtub *** structural properties of the proposed model are acquired including quantile function,moments,entropies,order statistics,residual life and reversed failure rate *** parameters of the distribution were estimated using the maximum likelihood *** maximum likelihood method is employed to estimate the model parameters and the approximate confidence intervals are also *** a simulation study,the performance of the point and interval estimates are compared using different *** real lifetime data sets,we verify that the offered model furnishes a better fit than some other lifetime models including Weibull,gamma and alpha powerWeibull models.

关键词： Weibull distribution modified alpha power transformationmethod maximum likelihood entropy order statistics

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Model Reduction via Reducibility Matrix

引用

Journal of Donghua University(English Edition) 2006年第6期23卷 110-112,124页

作者： Musa abdalla Othman Alsmadi Faculty of Engineering and Technology University of Jordan Amman Jordan

In this work, a new model reduction technique is introduced. The proposed technique is derived using the matrix reducibility concept. The eigenvalues of the reduced model are preserved; that is, the reduced model eigenvalues are a subset of the full order model eigenvalues. This preservation of the eigenvalues makes the mathematical model closer to the physical model. Finally, the outcomes of this method are fully illustrated using simulations of two numeric examples.

关键词： model reduction reducibility matrix LMI singular perturbation.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

New phase transitions for formulas in Lukasiewicz logic

引用

Frontiers of Computer Science 2020年第6期14卷 197-199页

作者： Mohamed EL HALABY Areeg abdalla Department of Mathematics Faculty of ScienceCairo UniversityGiza 12613Egypt

1 Introduction L-clausal forms is an interesting class of formulas in Eukasiewicz logic that was shown to be NP-complete[1].These formulas are defined over the following Lukasiewicz operations:negation-x=1-x strong di... 详细信息

关键词： formulas transitions Lukasiewicz

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Effect of medicinal plants on Moraxella cattarhalis

引用

Asian Pacific Journal of Tropical Medicine 2011年第2期4卷 133-136页

作者： Mohammed Uddin rasheed Thajuddin N Department of Medical Microbiology Haramaya UniversityHararEthiopia Department of Microbiology Bharathidasan UniversityTiruchirappalli-620 024TamilnaduIndia

Objective:To determine the antimoraxella activity of Ethiopian medicinal plants extracts. Methods:Two clinical isolates of Moraxella cattarhalis(***) with different antibiotic sensitivity pattern were tested to determine their susceptibility to garlic[Allium sativum(A. sativum)],bark of cinnamon[Cinnamomum zeylanicum(***)],clove[Syzygium aromaticum(***)],and leaves of avocado[Persea americana(***)], rosemary[Rosmarinus of ficinalis(*** ficinalis)]and prickly poppy[Argemone mexicana(A. mexicana)].Disk diffusion assay and broth dilution method were used to measure zone of inhibition,minimum inhibitory concentration(MIC) and minimum bactericidal concentration (MBC) of plant extracts against ***:Both the strains of *** exhibited similar sensitivities to the extracts of medicinal *** activity was exhibited only by garlic,avocado leaves and *** was found to be more antagonistic to *** than cinnamon and *** and avocado leaves have shown similar MIC(30 mg/mL) where as their zone of inhibition(15 and 11 mm,respectively) were different. Conclusions:Garlic,cinnamon and avocado leaves extracts represents alternative source of natural antimicrobial substances for use in clinical practice for the treatment of cases of M. *** research on the effects of these extracts on *** can be rewarding to pursue in the search for new broad spectrum antimicrobial agents.

关键词： Moraxella cattarhalis Minimum inhibitory concentration Minimum bactericidal concentration

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Effects of plant growth-promoting rhizobacteria on the molecular responses of maize under drought and heat stresses: A review

引用

Pedosphere 2022年第1期32卷 90-106页

作者： Iviwe NOTUNUNU Lucy MOLELEKI Ashira ROOPNARAIN rasheed ADELEKE Department of Biochemistry Genetics and MicrobiologyForestry and Agricultural Biotechnology InstituteUniversity of PretoriaLynnwood RdHatfieldPretoria 0002South Africa Microbiology and Environmental Biotechnology Research Group Agricultural Research Council—Natural Resources and EngineeringPrivate Bag X79Pretoria 0001South Africa Unit for Environment Science and Management North-West University(Potchefstroom Campus)Potchefstroom 2520South Africa

Drought and heat are major environmental stresses that continually influence plant growth and development. Under field conditions, these stresses occur more frequently in combination than alone, which magnifies corresponding detrimental effects on the growth and productivity of agriculturally important crops. Plant responses to such abiotic stresses are quite complex and manifested in a range of developmental, molecular, and physiological modifications that lead either to stress sensitivity or tolerance/resistance. Maize (Zea mays L.) is known for its sensitivity to abiotic stresses, which often results in substantial loss in crop productivity. Bioaugmentation with plant growth-promoting rhizobacteria (PGPR) has the potential to mitigate the adverse effects of drought and heat stresses on plants. Hence, this is considered a promising and eco-friendly strategy to ensure sustainable and long-term maize production under adverse climatic conditions. These microorganisms possess various plant growth-promoting (PGP) characteristics that can induce drought and heat tolerance in maize plants by directly or indirectly influencing molecular, metabolic, and physiological stress responses of plants. This review aims to assess the current knowledge regarding the ability of PGPR to induce drought and heat stress tolerance in maize plants. Furthermore, the drought and heat stress-induced expression of drought and heat stress response genes for this crop is discussed with the mechanisms through which PGPR alter maize stress response gene expression.

关键词： abiotic stress drought stress gene expression heat stress stress response gene stress tolerance Zea Mays L.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Pan-African high-grade metamorphism of southern Sinai, Egypt, fluid inclusion evidence

引用

Chinese Journal Of Geochemistry 2009年第4期28卷 358-363页

作者： Mohamed El Tokhi abdalla Musallum Geology Department College of Science United Arab Emirates UniversityUnited Arab Emirates

Fluid inclusions in the leucosomes of Wadi Feiran migmatites showed that CO2, H2O and (H2O-CO2) fluids were likely to have been present when partial melting began in these rocks. Low salinity, aqueous fluid, to a lesser extent, CO2-rich fluids are the most abundant fluids. The present study suggests that high-density CO2 inclusions were formed at the earliest stage, while H2O inclusions were formed at the late stage. In an intermediate stage, low-density CO2 and H2O, CO2 inclusions were formed. At the early stage of uplift and during melt crystallization, the CO2-bearing vapour was trapped at grain boundaries. At the late stage of uplift, H2O released at the time of crystallization of the melt was trapped as inclusions.

关键词：流体包裹体西奈半岛变质作用埃及证据二氧化碳局部熔融熔体包裹体

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Adversarial Attacks on Featureless Deep Learning Malicious URLs Detection

引用

Computers, Materials & Continua 2021年第7期68卷 921-939页

作者： Bader rasheed Adil Khan S.M.Ahsan Kazmi rasheed Hussain Md.Jalil Piran Doug Young Suh Institute of Data Science and Articial Intelligence Innopolis UniversityInnopolis420500Russia Institute of Information Security and Cyberphysical Systems Innopolis UniversityInnopolis420500Russia Department of Computer Science and Engineering Sejong UniversitySeoulKorea Department of Electronics Engineering Kyung Hee UniversityYonginKorea

Detecting malicious Uniform Resource Locators(URLs)is crucially important to prevent attackers from committing *** researches have investigated the role of machine learning(ML)models to detect malicious *** using ML algorithms,rst,the features of URLs are extracted,and then different ML models are *** limitation of this approach is that it requires manual feature engineering and it does not consider the sequential patterns in the ***,deep learning(DL)models are used to solve these issues since they are able to perform featureless ***,DL models give better accuracy and generalization to newly designed URLs;however,the results of our study show that these models,such as any other DL models,can be susceptible to adversarial *** this paper,we examine the robustness of these models and demonstrate the importance of considering this susceptibility before applying such detection systems in real-world *** propose and demonstrate a black-box attack based on scoring functions with greedy search for the minimum number of perturbations leading to a *** attack is examined against different types of convolutional neural networks(CNN)-based URL classiers and it causes a tangible decrease in the accuracy with more than 56%reduction in the accuracy of the best classier(among the selected classiers for this work).Moreover,adversarial training shows promising results in reducing the inuence of the attack on the robustness of the model to less than 7%on average.

关键词： Malicious URLs detection deep learning adversarial attack web security

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Electromagnetic Time Reversal Algorithms and Source Localization in Lossy Dielectric Media

引用

Communications in Theoretical Physics 2014年第12期61卷 779-789页

作者： Abdul Wahab Amer rasheed Tasawar Hayat Rab Nawaz Department of Mathematics COMSATS Institute of Information Technology Department of Mathematics Quaid-i-Azam University Nonlinear Analysis and Applied Mathematics (NAAM) Research Group Faculty of Science King Abdulaziz University

The problem of reconstructing the spatial support of an extended radiating electric current source density in a lossy dielectric medium from transient boundary measurements of the electric fields is studied. A time reversal algorithm is proposed to localize a source density from loss-less wave-field measurements. Further, in order to recover source densities in a lossy medium, we first build attenuation operators thereby relating loss-less waves with lossy ones. Then based on asymptotic expansions of attenuation operators with respect to attenuation parameter, we propose two time reversal strategies for localization. The losses in electromagnetic wave propagation are incorporated using the Debye's complex permittivity, which is well-adopted for low frequencies(radio and microwave) associated with polarization in dielectrics.

关键词： time reversal electromagnetic waves inverse source problem Debye’s law attenuation operators

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Combination of Model-based Observer and Support Vector Machines for Fault Detection of Wind Turbines

引用

International Journal of Automation and computing 2014年第3期11卷 274-287页

作者： Nassim Laouti Sami Othman mazen Alamir Nida Sheibat-Othman Université de Lyon Université Lyon 1 CNRS CPE Lyon UMR 5007 LAGEP F-69616 Villeurbanne France Gipsa-lab/CNRS University of Grenoble Rue de la Houille Blanche 38400 Saint Martin d Heres France

Support vector machines and a Kalman-like observer are used for fault detection and isolation in a variable speed horizontalaxis wind turbine composed of three blades and a full converter. The support vector approach is data-based and is therefore robust to process knowledge. It is based on structural risk minimization which enhances generalization even with small training data set and it allows for process nonlinearity by using flexible kernels. In this work, a radial basis function is used as the kernel. Different parts of the process are investigated including actuators and sensors faults. With duplicated sensors, sensor faults in blade pitch positions,generator and rotor speeds can be detected. Faults of type stuck measurements can be detected in 2 sampling periods. The detection time of offset/scaled measurements depends on the severity of the fault and on the process dynamics when the fault occurs. The converter torque actuator fault can be detected within 2 sampling periods. Faults in the actuators of the pitch systems represents a higher difficulty for fault detection which is due to the fact that such faults only affect the transitory state(which is very fast) but not the final stationary state. Therefore, two methods are considered and compared for fault detection and isolation of this fault: support vector machines and a Kalman-like observer. Advantages and disadvantages of each method are discussed. On one hand, support vector machines training of transitory states would require a big amount of data in different situations, but the fault detection and isolation results are robust to variations in the input/operating point. On the other hand, the observer is model-based, and therefore does not require training, and it allows identification of the fault level, which is interesting for fault reconfiguration. But the observability of the system is ensured under specific conditions, related to the dynamics of the inputs and outputs. The whole fault detection

关键词： Fault detection and isolation wind turbine Kalman-like observer support vector machines data-based classification

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：