检索结果-南通市图书馆

A Contemporary Review on Drought Modeling Using Machine Learning Approaches

Computer Modeling in Engineering & Sciences 2021年第8期128卷 447-487页

作者： Karpagam Sundararajan Lalit Garg Kathiravan Srinivasan Ali Kashif Bashir Jayakumar Kaliappan Ganapathy Pattukandan Ganapathy Senthil Kumaran Selvaraj t.meena School of Information technology and Engineering Vellore Institute of TechnologyVellore632014India Faculty of Information and Communication technology University of MaltaMsidaMSD2080Malta Department of Computing and Mathematics Manchester Metropolitan UniversityManchesterM156BHUK School of Computer Science and Engineering Vellore Institute of TechnologyVellore632014India Centre for Disaster Mitigation and Management Vellore Institute of TechnologyVellore632014India Department of Manufacturing Engineering School of Mechanical EngineeringVellore Institute of TechnologyVellore632014India School of Civil Engineering Vellore Institute of TechnologyVellore632014India

Drought is the least understood natural disaster due to the complex relationship of multiple contributory factors. Itsbeginning and end are hard to gauge, and they can last for months or even for years. India has faced many droughtsin the last few decades. Predicting future droughts is vital for framing drought management plans to sustainnatural resources. the data-driven modelling for forecasting the metrological time series prediction is becomingmore powerful and flexible with computational intelligence techniques. Machine learning (ML) techniques havedemonstrated success in the drought prediction process and are becoming popular to predict the weather, especiallythe minimum temperature using backpropagation algorithms. the favourite ML techniques for weather forecastinginclude support vector machines (SVM), support vector regression, random forest, decision tree, logistic regression,Naive Bayes, linear regression, gradient boosting tree, k-nearest neighbours (KNN), the adaptive neuro-fuzzyinference system, the feed-forward neural networks, Markovian chain, Bayesian network, hidden Markov models,and autoregressive moving averages, evolutionary algorithms, deep learning and many more. this paper presentsa recent review of the literature using ML in drought prediction, the drought indices, dataset, and performancemetrics.

关键词： Drought forecasting machine learning drought indices stochastic models fuzzy logic dynamic method hybrid method

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

Mitigation of EDFA transient effects in variable duty cycle pulsed signals

引用

Defence technology（防务技术） 2019年第3期15卷 276-281页

作者： D. meena K.t. Sarath Fredy Francis E. Dipin t. Srinivas Electronics and Radar Development Establishment (LRDE) DRDO Bangalore Karnataka 560093 India Model Engineering College Thrikkakara Cochin Kerala 682021 India Indian Institute of technology Madras Chennai Tamil Nadu 600036 India

We report the transient effects in Erbium Doped Fiber Amplifier (EDFA) systems for pulsed signals with different duty-cycles. the work includes the analysis using three different duty-cycles, 10%, 20% and 50%. A curve fitting technique is also proposed to predict the transients of any lesser duty-cycled pulse, once the transients of a larger duty-cycled pulse is known. Mathematical evaluation confirms the double exponential shape of transient distorted signal. Further, EDFA transient effect is experimentally verified on a Wavelength Division Multiplexed (WDM) link by multiplexing high and low bitrate modulated optical signals. We conclude the paper by proposing a transient suppression technique for variable dutycycle signals and analyzing its effectiveness with different wavelength spacing.

关键词： EDFA transients WDM Variable duty cycle Suppression

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

An enhanced cosine-based visual technique for the robust tweets data clustering

引用

International Journal of Intelligent Computing and Cybernetics 2021年第2期14卷 170-184页

作者： Narasimhulu K. meena Abarna K.t. Sivakumar B. Annamalai University ChidambaramIndiaand Rajeev Gandhi Memorial College of Engineering and technology NandyalIndia

Purpose-the purpose of the paper is to study multiple viewpoints which are required to access the more informative similarity features among the tweets documents,which is useful for achieving the robust tweets data clustering ***/methodology/approach-Let“N”be the number of tweets documents for the topics *** texts,punctuations and other symbols are removed,tokenization and stemming operations are performed in the initial tweets pre-processing ***-of-features are determined for the tweets;later tweets are modelled with the obtained bag-of-features during the process of topics *** of topics features are extracted for every tweet *** set of topics features of N documents are treated as *** key idea of the proposed work is to use multi-viewpoints in the similarity features *** following figure illustrates multi-viewpoints based cosine similarity computation of the five tweets documents(here N 55)and corresponding documents are defined in projected space with five viewpoints,say,v_(1),v_(2),v_(3),v4,and *** example,similarity features between two documents(viewpoints v_(1),and v_(2))are computed concerning the other three multi-viewpoints(v_(3),v4,and v5),unlike a single viewpoint in traditional cosine ***-Healthcare problems with tweets *** models play a crucial role in the classification of health-related tweets with finding topics(or health clusters)instead of finding term frequency and inverse document frequency(tF-IDF)for unlabelled ***/value-topic models play a crucial role in the classification of health-related tweets with finding topics(or health clusters)instead of finding tF-IDF for unlabelled tweets.

关键词： tweets data clustering topic models tF-IDF Similarity features Visual technique VAt cVAt MVCS-VAt

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

Conservation of an important montane bamboo thamnocalamus falconeri, *** Munro through axillary bud proliferation

引用

Journal of Forestry Research 2015年第1期26卷 179-185页

作者： meena Bakshi Chandrakant tiwari Sajad Razvi Plant Physiology Discipline Botany DivisionForest ResearchInstitute

thamnocalamus falconeri, Hook.f. ex Munro.,an important bamboo species belonging to the family Poaceae, locally known as Ringal, occurs in the hills of Uttarakhand, India. this species has been traditionally exploited by local communities to support their *** needs of the hill villages impose unsustainable pressure on natural stands of Ringal in the Uttarakhand hills and forests have been degraded. the long history of excessive cutting of Ringal from natural forests and the lack of replanting threaten villager livelihoods. Replanting is required to conserve the species. We propose a protocol for generation of planting material through axillary bud proliferation for multiplication and conservation of this species. We collected offsets/rhizomes from a natural stand of t. falconeri in the Chopta Mandal areas（Chamoli district, India）. these were planted at sites of varied elevation and fresh single nodal segments were collected from them as explants. Different sterilization treatments were assessed to combat contamination. Among these, treatment of 0.1 %Hg Cl2 followed by 5 % Na OCl, proved best. Among two cytokinin treatments, viz. BAP and Kinetin, singly or in combination, BAP alone（5 mg L-1） proved superior and resulted in 100 % bud break. BAP-supplemented MS media yielded maximum vigorous shoot formation（90 %）and maximum number of shoots（8.9）. Subculturing of shoots on the same medium with similar BAP treatment（5 mg L-1BAP） enabled continuous production of healthy shoots at similar frequency. Maximum rooting（100 %）was recorded on half-strength MS medium supplemented with 5 mg L-1IBA. Micropropagated plants were hardened and acclimatized in soil mixture（2：1：1） and then transplanted to field sites（Magra, Uttarakhand, 1,834 m）.Eight to ten months after field transplantation we recorded100 % survival of transplanted material. this micropropagation protocol could be used successfully for raising a stock of genetically homogenous plant material in bulk

关键词： thamnocalamus falconeri Micropropagation MS medium Axillary bud proliferation Hormones

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

tMtACS: two-tier Multi-trust-Based Algorithm to Countermeasure the Sybil Attacks

引用

Computers, Materials & Continua 2022年第11期73卷 3497-3512页

作者： meena Bharti Shaveta Rani Paramjeet Singh Department of Computer Science and Engineering I.K.Gujral Punjab Technical UniversityKapurthala144603PunjabIndia Department of Computer Science and Engineering Maharaja Ranjit Singh Punjab Technical UniversityBathinda151001PunjabIndia

Mobile Ad hoc Networks(MANEts)have always been vulnerable to Sybil attacks in which users create fake nodes to trick the system into thinking they’re *** fake nodes need to be detected and deactivated for security reasons,to avoid harming the data collected by various *** MANEt is an emerging field that promotes trust management among *** is becoming more essential in the communication process,which is why clear and honest communication strategies are *** Management allows for MANEt devices with different security protocols to *** a device finds difficulty in sending a message to the destination,the purpose of the communication process won’t be achieved and this would disappoint both that device and all of your devices in *** paper presents,the two-tier Multi-trust based Algorithm for Preventing Sybil Attacks in MANEts(tMtACS).the tMtACS provides a two-tier security mechanism that can grant or revoke trust in the Nodes of the ***’s a smart way to identify Sybil nodes in the system.A proficient cluster head selection algorithm is also defined,which selects cluster head efficiently and does load balancing to avoid resource consumption from a single node ***,for routing efficient path is selected to deteriorate energy consumption and maximize *** recent technique is compared with Secured QoS aware Energy Efficient Routing(SQEER),Adaptive trust-Based Routing Protocol(AtRP),and Secure trust-Aware Energy-Efficient Adaptive Routing(StEAR)in terms of Packet Delivery Ratio(PDR),consumption of energy *** simulation was performed on MAtrix LABoratory(MAtLAB)and the results achieved by the present scheme are better than existing techniques.

关键词： Malicious node sybil attack MANEt trust management 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

Feasibility analysis of WDM links for radar applications

引用

Defence technology（防务技术） 2015年第1期11卷 76-84页

作者： D.meena FREDY FRANCIS K.t.SARAtH E.DIPIN t.SRINIVAS Applied Photonics Lab ECE Department Indian Institute of Science(IISc) Electronics and Radar Development Establishment (LRDE) DRDO(Ministry of Defence) Bangalore India Model Engineering College Thrikkakara Cochin India

Active phased array antennas enhances the performance of modern radars by using multiple low power transmit/receive modules in place of a high power transmitter in conventional radars. Fully distributed phased array radars demand the distribution of various signals in radio frequency(RF) and digital domain for real time operation. this is normally achieved through complex and bulky coaxial distribution networks. In this work, we intend to tap the inherent advantages of fiber links with wavelength division multiplexed(WDM) technology and a feasibility study to adapt these links for radar applications is carried out. this is done by analysing various parameters like amplitude, delay, frequency and phase variation response of various radar waveforms over WDM links. this also includes performance evaluation of non-linear frequency modulation(NLFM) signals, known for better signal to noise ratio(SNR) to specific side lobe levels. NLFM waveforms are further analysed using pulse compression(PC) technique. Link evaluation is also carried out using a standard simulation environment and is then experimentally verified with other waveforms like RF continuous wave(CW), pulsed RF and digital signals. Synchronization signals are generated from this variable duty cycle digital signals during real time radar operation. During evaluation of digital signals, variable transient effects for different duty cycles are observed from an amplifier configuration. A suppression method is proposed to eliminate this transient effects. Further, the link delay response is investigated using different lengths of fiber spools. It can be inferred from the experimental results that WDM links are capable of handling various signals significant to radar applications.

关键词： WDM Radar RF over fiber EDFA transient Delay CW Pulsed CW NLFM

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

transport mechanism in chemically reactive hybrid nanofluid flow containing gyrotactic micro-organisms over a curved oscillatory surface

引用

Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 177-192页

作者： M.NAVEED M.IMRAN t.ASGHAR Z.ABBAS Department of Mathematics Division of Science and TechnologyUniversity of Education Department of Mathematics The Islamia University of Bahawalpur

this paper examines the transport analysis, including both heat transfer and mass transfer, in hybrid nanofluid flow containing gyrotactic microorganisms towards a curved oscillatory surface. the influence of magnetic fields is also inspected in terms of their physical characteristics. to depict the phenomena of transport, modified versions of both Fick's and Fourier's laws are used. Additionally, the characteristics of both heterogeneous and homogeneous chemical reactions are also incorporated. Utilizing a curvilinear coordinate system, the flow problem is formulated as partial differential equations(PDEs)for momentum, concentration, microorganism field, and energy. An analytical solution to the obtained flow equations is achieved utilizing the homotopy analysis method(HAM).the effects of significant flow parameters on the pressure and microorganism fields, velocity, oscillation velocity, concentration, and temperature distributions are shown via graphs. Furthermore, the variations in skin friction, mass transfer rate, heat transfer rate, and local motile number due to different involved parameters are presented in tables and are analyzed in detail. Graphical results indicate that the curves of velocity and temperature fields are enhanced as the values of the solid volume fraction variables *** is also verified that the concentration rate field decreases as the values of the homogeneous reaction strength parameter and the radius of curvature parameter increase, and it increases with the Schmidt number and the heterogeneous reaction strength *** outcomes show a favorable response of the motile number to advanced values of the Peclet number, the Schmidt number, the microorganism difference parameter, and the bio-convective Lewis number.

关键词：

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Study of locust bean gum reinforced cyst-chitosan and oxidized dextran based semi-IPN cryogel dressing for hemostatic application

引用

Bioactive Materials 2018年第3期3卷 370-384页

作者： Lalit Kumar meena Pavani Raval Dhaval Kedaria Rajesh Vasita School of Life Sciences Central University of GujaratSector-30Gandhinagar 382030India Government Engineering College Sector-28Gandhinagar 382028India

Severe blood loss due to traumatic injuries remains one of the leading causes of death in emergency *** continues to be the candidate material for hemostatic applications due to its inherent hemostatic ***,available chitosan-based dressings have been reported to have an acidic odor at the wound site due to the incorporation of acid based solvents for their fabrication and deformation under compression owing to low mechanical strength limiting its *** the present study semi-IPN cryogel was fabricated via Schiff's base cross-linking between the polyaldehyde groups of oxidized dextran and thiolated chitosan in presence of locust bean gum(LBG)known for its *** at12C yielded macroporous semi-IPN cryogels with an average pore size of 124.57±20.31 mm and 85.46%*** hydrophobicity index of LBG reinforced semi-IPN cryogel was reduced 2.42 times whereas the swelling ratio was increased by 156.08%compare to control *** increased hydrophilicity and swelling ratio inflated the compressive modulus from 28.1 kPa to 33.85 for LBG reinforced semi-IPN *** structural stability and constant degradation medium pH were also recorded over a period of 12 *** cryogels demonstrated lower adsorption affinity towards *** cytotoxicity assays(direct,indirect)with 3t3-L1 fibroblast cells confirmed the cytocompatibility of the *** hemolysis assay showedtibility of the fabricated cryogel,while whole blood clotting and platelet adhesion assays confirmed the hemostatic potential of semi-IPN cryogel.

关键词： Chitosan Oxidized dextran Locust bean gum Cryogel Hemostasis

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

Soil moisture controls the spatio-temporal pattern of soil respiration under different land use systems in a semi-arid ecosystem of Delhi,India

引用

Ecological Processes 2020年第1期9卷 172-184页

作者： Archana meena M.Hanief J.Dinakaran K.S.Rao Department of Botany University of RajasthanJaipurRajasthan 302004India Department of Botany Baba Ghulam Ghulam Shah Badshah UniversityRajouriJammu and Kashmir 185234India Department of Botany Bhaskaracharya College of Applied SciencesUniversity of DelhiDwarkaDelhi 110007India Department of Botany University of DelhiDelhi 110007India

Background:Soil respiration(S_(R))is a critical process for understanding the impact of climatic conditions and land degradation on the carbon cycle in terrestrial *** measured the S_(R) and soil environmental factors over 1 year in four land uses with varying levels of disturbance and different vegetation types viz.,mixed forest cover(MFC),Prosopis juliflora(Sw.)forest cover(PFC),agricultural field(AF),and vegetable field(VF),in a semi-arid area of Delhi,*** primary aim was to assess the effects of soil moisture(S_(M)),soil temperature(S_(t)),and soil microbial activity(S_(MA))on the S_(R).Methods:the S_(R) was measured monthly using an LI-6400 with an infrared gas analyser and a soil *** S_(M) was measured using the gravimetric *** S_(t)(10 cm)was measured with a probe attached to the *** S_(MA) was determined by fluorescein diacetate ***:the S_(R) showed seasonal variations,with the mean annual S_(R) ranging from 3.22 to 5.78μmol m^(−2) s^(−1) and higher S_(R) rates of~15-55%in the cultivated fields(AF,VF)than in the forest sites(MFC,PFC).the VF had significantly higher S_(R)(Pthan the other land uses(AF,PFC,MFC),which did not vary significantly from one another in S_(R)(Pthe repeated measures ANOVA evaluated the significant differences(Pthe S_(R) for high precipitation months(July,August,September,February).the S_(M) as a single factor showed a strong significant relationship in all the land uses(R^(2)=0.67-0.91,Pthe effect of the S_(t) on the S_(R) was found to be weak and non-significant in the PFC,MFC,and AF(R^(2)=0.14-0.31;P>0.05).Contrasting results were observed in the VF,which showed high S_(R) during summer(May;11.21μmol m^(−2) s^(−1))and a significant exponential relationship with the S_(t)(R^(2)=0.52;Pthe S_(R) was positively related to the SMA(R2=0.44-0.5;Pthe interactive equations based on the independent variables S_(M),S_(t),and S_(MA) explained 91-95

关键词： Soil respiration Soil moisture Soil microbes Soil temperature Precipitation Land use change Semi-arid ecosystems

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

Free vibration and transient response of double curved beams connected by intermediate straight beams

引用

Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 37-62页

作者： R.A.JAFARI-tALOOKOLAEI H.GHANDVAR E.JUMAEV S.KHAtIR t.CUONG-LE School of Mechanical Engineering Babol Noshirvani University of Technology Department of Mechanical Engineering Faculty of Engineering New Uzbekistan University University of Business and Science Center for Engineering Application and technology Solutions Ho Chi Minh City Open University

this paper investigates the free vibration and transient response of interconnected structures including double curved beams and intermediate straight beams,which are all constructed from functionally graded porous(FGP) materials. the strain potential and kinetic energies of each beam along with the work done by the external force are calculated. Additionally, a higher-order beam element is introduced to derive stiffness and mass matrices, along with the force vector. the curved and straight beams are discretized, and their assembled stiffness, mass matrices, and force vectors, are *** conditions at the joints are used to derive the total matrices of the entire structure. Subsequently, the natural frequencies and transient response of the system are determined. the accuracy of the mathematical model and the self-developed computer program is validated through the comparison of the obtained results with those of the existing literature and commercial software ANSYS, demonstrating excellent ***, a comprehensive study is conducted to investigate the effects of various parameters on the free vibration and transient response of the considered structure.

关键词：

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

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：