检索结果-南通市图书馆

A system dynamics model for billion trees tsunami afforestation project of Khyber Pakhtunkhwa in Pakistan:Model application to afforestation activities

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

Journal of Mountain Science 2019年第11期16卷 2640-2653页

作者： Naila NAZIR Aqsa FAROOQ Sajjad ahmad JAN Aftab ahmad Department of Economics University of PeshawarKhyber Pakhtunkhwa 25000Pakistan Department of Economics Edwardes CollegePeshawar Saddar 25000Pakistan Global Change Impact Study Center Ministry of Climate Change10-Mauve AreaG-8/1IslamabadPakistan

As part of the global effort to plant billion trees,an afforestation project is launched in Pakistan in Khyber Pakhtunkhwa(KP)province to conserve existing forests and to increase area under forest *** present study is designed to build a Systems'model by incorporating major activities of the Billion Tree Tsunami Afforestation Project(BTTAP)with special focus on afforestation activities to estimate the growth in forest area of *** of complete dataset was a *** fix the model,the raw data taken from the project office has been *** Commission Form 1-Phase I&II helped us with additional *** relied on the data available for one and half period of the project as rest of the data is subject to the completion of the *** results show that the project target to enhance area under forest differs from the target to afforest area under the *** system dynamics'model projection shows that the forest area of KP would be 23.59 million hectares at the end of the BTTA project,thus having an increase of 3.29%instead of 2%that has been initially ***,the results show that the progress to meet the target in some afforestation classes is slow as compared to other *** forestry,plantation on communal lands and owners'plantation need special focus of the *** would affect 0.02 million hectares area of the *** model under study may be used as a reference model that can be replicated to other areas where billion tree campaigns are going on.

关键词： Billion trees project Afforestation System dynamic model Forest area Deforestation Pakistan

Synchronous self-learning Pareto strategy An ensemble framework for vector and multi-criterion optimization

在线全文

学校读者我要写书评

暂无评论

International Journal of Intelligent Computing and Cybernetics 2018年第2期11卷 197-233页

作者： ahmad Mozaffari Systems Design Engineering Department University of WaterlooWaterlooCanada

Purpose–In recent decades,development of effective methods for optimizing a set of conflicted objective functions has been absorbing an increasing interest from *** refers to the essence of real-life engineering systems and complex natural mechanisms which are generally multi-modal,non-convex and *** now,several deterministic and stochastic methods have been proposed to cope with such complex *** soft computational methods such as evolutionary games(cooperative and non-cooperative),Pareto-based techniques,fuzzy evolutionary methods,cooperative bio-inspired algorithms and neuro-evolutionary systems have effectively come to the aid of researchers to build up efficient paradigms with application to vector *** paper aims to discuss this ***/methodology/approach–A novel hybrid algorithm called synchronous self-learning Pareto strategy(SSLPS)is presented for the sake of vector *** method is the ensemble of evolutionary algorithms(EA),swarm intelligence(SI),adaptive version of self-organizing map(CSOM)and a data shuffling *** are powerful numerical optimization algorithms capable of finding a global extreme point over a wide exploration *** techniques(the swarm of bees in our case)can improve both intensification and robustness of *** network is an unsupervised learning methodology which learns the characteristics of non-dominated solutions and,thus,enhances the quality of the Pareto ***–To prove the effectiveness of the proposed method,the authors engage a set of well-known benchmark functions and some well-known rival optimization ***,SSLPS is employed for optimal design of shape memory alloy actuator as a nonlinear multi-modal real-world engineering *** experiments show the acceptable potential of SSLPS for handling both numerical and engineering multi-objective ***/value–To the author’s best knowledge,the propos

关键词： Self-organizing map Swarm and evolutionary computation Unsupervised machine assisted optimization Vector optimization

Evaluation of stiffness in a cellulose fiber reinforced epoxy laminates for structural applications:Experimental and finite element analysis

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

Defence Technology（防务技术） 2018年第4期14卷 278-286页

作者： Furkan ahmad Pramendra Kumar Bajpai MPAE Division Netaji Subhas Institute of TechnologyUniversity of Delhi

Natural fiber composites have been proved to have the ability to replace the synthetic fiber composites in many structural applications. Unprecedented growth in the field of computational techniques has opened the doors of analysis and simulation of composite materials under various *** and simulation using various available softwares saves a lot of time and resources. In the present work, an attempt has been made to analyze the tensile behavior of jute fiber reinforced epoxy based polymer composite materials using the student version of commercially available finite element code Siemens PLM NX 10.0. In most of the structural applications, materials are required to have enough stiffness to resist the shape deformation under normal loading conditions. Therefore, emphasis is given to the load-deformation behavior of the developed composites. A 3-dimensional model of the test specimen was developed using ply-stacking method and the strain-stress values were verified by the available literature. The model showed a good agreement between the experimental and software results. Effect of ply angle, fiber percentage, fiber type, number of layers and weft fiber angle on the stiffness of laminate have been studied.

关键词： Finite element analysis Jute fiber Polymer composite Ply-stacking Weft fiber angle Laminates analysis

Federated Learning Security and Privacy-Preserving Algorithm and Experiments Research Under Internet of Things Critical Infrastructure

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2024年第2期29卷 400-414页

作者： Nasir ahmad Jalali Hongsong Chen Department of Computer Science University of Science and Technology Beijing(USTB)Beijing 100083China

The widespread use of the Internet of Things(IoTs)and the rapid development of artificial intelligence technologies have enabled applications to cross commercial and industrial band *** such systems,all participants related to commercial and industrial systems must communicate and generate ***,due to the small storage capacities of IoT devices,they are required to store and transfer the generated data to third-party entity called“cloud”,which creates one single point to store their ***,as the number of participants increases,the size of generated data also ***,such a centralized mechanism for data collection and exchange between participants is likely to face numerous challenges in terms of security,privacy,and *** address these challenges,Federated Learning(FL)has been proposed as a reasonable decentralizing approach,in which clients no longer need to transfer and store real data in the central ***,they only share updated training models that are trained over their private *** the same time,FL enables clients in distributed systems to share their machine learning models collaboratively without their training data,thus reducing data privacy and security ***,slow model training and the execution of additional unnecessary communication rounds may hinder FL applications from operating properly in a distributed ***,these unnecessary communication rounds make the system vulnerable to security and privacy issues,because irrelevant model updates are sent between clients and ***,in this work,we propose an algorithm for fully homomorphic encryption called Cheon-Kim-Kim-Song(CKKS)to encrypt model parameters for their local information privacy-preserving *** proposed solution uses the impetus term to speed up model convergence during the model training ***,it establishes a secure communication channel between IoT devices and the *** a

关键词： Federated Learning(FL) Internet of Things(IoTs) lightweight Transport Layer Security(iTLS) Cheon-Kim-Kim-Song(CKKS)

CHEMICAL SYNTHESIS,SPECTRAL CHARACTERIZATION AND STABILITY OF SOME ELECTRICALLY CONDUCTING POLYMERS

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

Chinese Journal of Polymer Science 2010年第2期28卷 191-197页

作者： Pradeep Kumar Upadhyay Afaq ahmad Department of Chemistry Aligarh Muslim University

The synthesis, characterization, thermal degradation and stability of polyaniline （PANI）, poly（m-nitroaniline）, poly（m-chloroaniline） and poly（o-methylaniline） were reported. Different properties were measured and compared with PANI to find out the effect of electron donating groups （-CH3） and electron withdrawing groups （-Cl, -NO2）. It was found that the presence of any type of substitution in the benzene ring of aniline increased the solubility but reduced the yield, thermal stability and electrical conductivity. Two probe methods were used to measure the electrical conductivity of these polymers. The structural properties of these polymers were characterized by using FTIR and UV-Vis spectroscopic methods. Thermal degradation and stability of these polymers were explained by using thermogravimetric analysis （TGA） and conductivity measurements.

关键词： Polyaniline Electrical conductivity Yield Thermal degradation Stability.

Free vibration analysis of non-homogeneous orthotropic plates resting on Pasternak elastic foundation by Rayleigh-Ritz method

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2016年第2期23卷 413-420页

作者： ahmad Rahbar-Ranji Arash Shahbaztabar Department of Ocean Engineering Amir Kabir University of Technology

Free vibration analysis of non-homogeneous orthotropic plates resting on a Pasternak type of elastic foundation is investigated. A set of admissible orthogonal polynomials are generated with Gram-Schmidt orthogonalization procedure and adopted in the Rayleigh-Ritz method. Accuracy and applicability of the method are examined by comparison of the results for different boundary conditions and material types with those available in literature. It is found that this method has good accuracy regardless of type of boundary condition and yields very accurate results even with low number of terms of orthogonal polynomials for the first mode of vibration. For higher modes of vibration, higher terms of orthogonal polynomials should be used. The effects of foundation parameter, density and non-homogeneity parameters on natural frequency are examined. It is concluded that natural frequency of plates are more sensitive to shearing layer coefficient rather than Winkler coefficient and density parameter has weakening effect on natural frequency.

关键词： free vibration non-homogeneous orthotropic plate Pastemak foundation Rayleigh-Ritz method Gram-Schmidt procedure

Performance improvement of complementary feeders using static transfer switch system

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第2期10卷 189-200页

作者： Tahir MAHMOOD Mohammad ahmad CHOUDHRY Department of Electrical Engineering University of Engineering and Technology

The performance of complementary feeders, running in parallel, can be significantly improved by installing static transfer switches （STSs） at critical locations. We develop the STS control logic, which transfers the critical load from the preferred feeder to the alternate feeder when a voltage sag or a fault occurs on the preferred feeder. A forced commutation technique is proposed and implemented to turn off the preferred feeders＇ thyristor, thus avoiding cross current to flow and minimizing the transfer time. Simulation results show that the forced commutation technique is more effective as compared to the recently proposed time delay technique for STS operation. Two different feeders, namely New Exchange, the preferred feeder, and Sector 1-10/2, the alternate feeder of Islamabad Electric Supply COmpany （IESCO）, Pakistan, have been selected for case studies. The software PSCAD/EMTDC professional package has been used for simulation.

关键词： Complementary feeder Cross current Static transfer switch (STS) Sensitive load Voltage sag PSCAD/EMTDC

Arabic Bank Check Processing: State of the Art

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2013年第2期28卷 285-299页

作者： Irfan ahmad Sabri A.Mahmoud Information and Computer Science Department King Fahd University of Petroleum & Minerals

In this paper, we present a general model for Arabic bank check processing indicating the major phases of a check processing system. We then survey the available databases for Arabic bank check processing research. The state of the art in the different phases of Arabic bank check processing is surveyed （i.e., pre-processing, check analysis and segmentation, features extraction, and legal and courtesy amounts recognition）. The open issues for future research are stated and areas that need improvements are presented. To the best of our knowledge, it is the first survey of Arabic bank check processing.

关键词： handwriting analysis document analysis text processing feature evaluation and selection pattern analysis

Experimental Study on Cross-Flow Induced Vibrations in Heat Exchanger Tube Bundle

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2017年第1期31卷 91-97页

作者： KHUSHNOOD Shahab NIZAM Luqman ahmad Department of Mechanical Engineering University of Engineering and Technology Taxila Pakistan Department of Mechanical Engineering HITEC University Taxila Pakistan

Vibration in heat exchangers is one of the main problems that the industry has faced over last few decades. Vibration phenomenon in heat exchangers is of major concern for designers and process engineers since it can lead to the tube damage, tube leakage, baffle damage, tube collision damage, fatigue, creep etc. In the present study, vibration response is analyzed on single tube located in the centre of the tube bundle having parallel triangular arrangement （60-） with P/D ratio of 1.44. The experiment is performed for two different flow conditions. This kind of experiment has not been reported in the literature. Under the first condition, the tube vibration response is analyzed when there is no internal flow in the tube and under the second condition, the response is analyzed when the internal tube flow is maintained at a constant value of 0.1 rn/s. The free stream shell side velocity ranges from 0.8 rn/s to 1.3 m/s, the reduced gap velocity varies from 1,80 to 2.66 and the Reynolds number varies from 44500 to 66000. It is observed that the internal tube flow results in larger vibration amplitudes for the tube than that without internal tube flow. It is also established that over the current range of shell side flow velocity, the turbulence is the dominant excitation mechanism for producing vibration in the tube since the amplitude varies directly with the increase in the shell side velocity. Damping has no significant effect on the vibration behavior of the tube for the current velocity range.

关键词： cross-flow tube bundle parallel Iriangular internal tube flow damping