检索结果-南通市图书馆

Numerical Integration Over Implicitly Defined Domains with Topological Guarantee

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Mathematics and Statistics 2019年第4期7卷 459-474页

作者： Tianhui Yang ammar Qarariyah Hongmei Kang Jiansong Deng School of Mathematical Science University of Science and Technology of ChinaHefeiChina School of Mathematical Sciences Soochow UniversitySuzhouChina

Numerical integration over the implicitly defined domains is challenging due to topological variances of implicit *** this paper,we use interval arithmetic to identify the boundary of the integration domain exactly,thus getting the correct topology of the ***,a geometry-based local error estimate is explored to guide the hierarchical subdivision and save the computation *** experiments are presented to demonstrate the accuracy and the potential of the proposed method.

关键词： Isogeometric analysis Numerical integration Implicitly defined domains Topological guarantee Interval arithmetic Local error estimate Hierarchical subdivision

Numerical Solution for Schrödinger Eigenvalue Problem Using Isogeometric Analysis on Implicit Domains

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Mathematics and Statistics 2020年第1期8卷 91-111页

作者： ammar Qarariyah Fang Deng Tianhui Yang Jiansong Deng School of Mathematical Sciences University of Science and Technology of ChinaHefei 230026China School of Mathematics and Statistics North China University of Water Resources and Electric PowerZhengzhou 450045HenanPeople’s Republic of China

We study the accuracy and performance of isogeometric analysis on implicit domains when solving time-independent Schrödinger *** construct weighted extended PHT-spline basis functions for analysis,and the domain is presented with same basis functions in implicit form excluding the need for a parameterization ***,an adaptive refinement process is formulated and discussed with *** constructed basis functions with cubic polynomials and only C^(1) continuity are enough to produce a higher continuous field approximation while maintaining the computational cost for the matrices as low as possible.A numerical implementation for the adaptivemethod is performed on Schrödinger eigenvalue problem with doublewell potential using 3 examples on different implicit *** convergence and performance results demonstrate the efficiency and accuracy of the approach.

关键词： Isogeometric analysis Finite element analysis PHT-splines Schrodinger equation Eigenvalue problems

The Design and Implementation of Video Conferencing System Based on ALM

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The Design and Implementation of Video Conferencing System B...

作者： ammar Oad 中南大学

学位级别：硕士

实时视频流应用系统,如可视电话、远程教育和视频会议,在未来的生活中有着重要作用。同时,应用层组播（ALM）是目前视频流技术非常重要的基础。上述两个方而仍面临诸多挑战,因此研究基于ALM的多媒体传输应用系统有重要意义。本文提... 详细信息

实时视频流应用系统,如可视电话、远程教育和视频会议,在未来的生活中有着重要作用。同时,应用层组播（ALM）是目前视频流技术非常重要的基础。上述两个方而仍面临诸多挑战,因此研究基于ALM的多媒体传输应用系统有重要意义。本文提出了一个基于ALM的视频会议系统设计。在功能上,本实时视频组播系统分为以下四个模块：视频采集模块、传输模块、服务器模块。系统采用混合P2P覆盖网组播树结构,减少了延迟和源端的压力,网路负载也得到平衡。为了提高视频的实时性,充当服务器的节点只负责管理成员关系信息,它负责应用层组播树的建立和维护。本文还提出了一个基于度约束的组播树算法设计,不仅考虑了带宽因素,还考虑了成员节点的计算能力。此外,为了提高组播效率,系统还使用了多线程技术和完成端口模型。由于视频捕捉模块中的相关技术比较成熟,考虑到在Windows环境下开发的需要,我们选择了Windows VFW作为视频技术平台。由于ALM的不稳定性,我们使用H.263标准作为视频编码,这是一种为低速率通信而设计的ITU-T标准。从分布式架构上看,系统由三部分组成：服务器、视频源和客户端。服务器只包括成员关系信息管理模块,而源端包括视频采集模块、编码模块和传输模块。客户端主要由传输模块和解码模块组成。这是一个计算机网络和多媒体技术的集成系统,有一定的实用价值。

关键词：应用层组播算法系统设计视频会议

Ultra-Stable Hybrid Nanofluids as Excellent Spectral Beam Splitters in Photovoltaic/Thermal Applications

同方学位论文库评论

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

Ultra-Stable Hybrid Nanofluids as Excellent Spectral Beam Sp...

作者： ammar Dmour 湖南大学

学位级别：硕士

光伏应用的一个重要问题是电池温度升高导致光伏组件的电效率降低。传统的方法集中于被动冷却方法来控制光伏组件的温度,但它们无法利用太阳能电池无法吸收的太阳能。因此,本工作开发了一种使用纳米流体的光谱分裂PV/T系统。由于其可调... 详细信息

光伏应用的一个重要问题是电池温度升高导致光伏组件的电效率降低。传统的方法集中于被动冷却方法来控制光伏组件的温度,但它们无法利用太阳能电池无法吸收的太阳能。因此,本工作开发了一种使用纳米流体的光谱分裂PV/T系统。由于其可调节的光谱吸收特性,纳米流体具有在光伏/热(PV/T)系统中用作光谱分束器(SBS)的潜力。然而,现有纳米流体光谱分束器稳定性的局限性阻碍了其在当前应用中的广泛使用。在本研究中,使用了由甘油(GL)和聚乙二醇(PEG)以及ATO和氧化铜(Cu O)以及ATO组成的碳量子点(CQD)纳米流体,这已被证明是PV/T系统中的优异光谱分束器。可以使用直接的微波加热方法来创建CQD纳米流体过滤器,其在长时间内表现出超稳定性。通过调节加热持续时间和PEG浓度,可以同时控制透射率曲线。通过延长加热过程,可以增加纳米流体在整个光谱中的吸收,并且可以通过改变PEG含量来控制纳米流体在特定波长下的吸收。这项研究为超稳定CQD-ATO和Cu O-ATO纳米流体作为光谱分束器在太阳能光PV/T应用中的广泛应用铺平了道路。

关键词：碳量子点氧化锑锡氧化铜纳米流体光伏/热系统光谱分束器

Power quality improvement using fuzzy logic controller for five-level shunt active power filter under distorted voltage conditions

同方学位论文库评论

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

Frontiers in Energy 2014年第2期8卷 212-220页

作者： Amar BENAISSA Boualaga RABHI ammar MOUSSI Department of Electrical Engineering University of Djelfa B.P.3117 Djelfa 17000 Algeria SE Laboratory University of Biskra B.P. 145 Biskra 07000 Algeria ARHYS Laboratory University of Biskra B.P.145 Biskra 07000 Algeria

In this paper, a five-level inverter is used as a shunt active power filter （APF）, taking advantages of the multilevel inverter such as low harmonic distortion and reduced switching losses. It is used to compensate reactive power and eliminate harmonics drawn from a thyristor rectifier feeding an inductive load （RL） under distorted voltage conditions. The APF control strategy is based on the use of self-tuning filters （STF） for reference current generation and a fuzzy logic current controller. The use of STF instead of classical extraction filters allows extracting directly the voltage and current fundamental components in the a-fl axis without phase locked loop （PLL）. The MATLAB fuzzy logic toolbox is used for implementing the fitzzy logic control algorithm. The obtained results show that the proposed shunt APF controller has produced a sinusoidal supply current with low harmonic distortion and in phase with the line voltage.

关键词： active power filter (APF) harmonics isolator distorted voltage conditions self-tuning filters (STF) fuzzy logic control

Generalization of Advanced Encryption Standard Based on Field of Any Characteristic

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2022年第12期73卷 6121-6138页

作者： Nabilah Abughazalah Majid Khan Noor Munir ammar SAlanazi Iqtadar Hussain Department of Mathematical Sciences College of SciencePrincess Nourah Bint Abdulrahman UniversityP.O.Box 84428Riyadh 11671Saudi Arabia Department of Applied Mathematics&Statistics Institute of Space TechnologyIslamabadPakistan King Abdulaziz City for Science and Technology RiyadhSaudi Arabia Mathematics Program Department of MathematicsStatistics and PhysicsCollege of Arts and SciencesQatar University2713DohaQatar Statistical Consulting Unit College of Arts and ScienceQatar UniversityDohaQatar

Nowadays most communications are done by utilizing digital transmission *** security of this digital information transmitted through different communication systems is quite *** secrecy of digital data is one of the burning topics of the digitally developed *** exist many traditional algorithms in the literature to provide methods for robust *** most important and recent modern block cipher named the advanced encryption standard(AES)is one of the extensively utilized encryption schemes with binary *** is a succession of four fundamental steps:round key,sub-byte,shift row,and mix *** this work,we will provide an innovative methodology for extending the AES in a Galois fieldwith any characteristic *** four steps in the fundamental process with binary characteristics will be adjusted because of the new *** applying double affine transformations,we have enhanced the number of options in our suggested substitution *** reconstruction of the nonlinear confusion component and encryption structure provides robustness in the generalized *** increase in the keyspace due to the Galois field generalization implies that we have improved additional confusion abilities and broadened the current *** implementation of the proposed structure of AES for image,audio,and video encryption will provide high security for secure communication.

关键词： AES generalized AES binary field ternary function

Non-phosgene synthesis of hexamethylene-1,6-diisocyanate from thermal decomposition of hexamethylene-1,6-dicarbamate over Zn–Co bimetallic supported ZSM-5 catalyst

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 Chemical Engineering 2019年第3期27卷 549-555页

作者： Yan Cao Yafang Chi ammar Muhammad Peng He liguo Wang Huiquan Li CAS Key Laboratory of Green Process and Engineering Institute of Process Engineering Chinese Academy of Sciences National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology Institute of Process Engineering Chinese Academy of Sciences University of Chinese Academy of Sciences

A non-phosgene route for the synthesis of hexamethylene-1,6-diisocyanate(HDI) was developed via catalytic decomposition of hexamethylene-1,6-dicarbamate(HDC) over Zn–Co bi-metallic supported ZSM-5 *** catalyst was characterized by FTIR and XRD analyses. Three solvents dioctyl sebacate(DOS), dibutyl sebacate(DBS) and 1-butyl-3-methylimidazolium tetrafluoroborate(BMIMBF_4) were investigated and compared; DOS gave better performance. The catalytic performances for thermal decomposition of HDC to HDI using DOS as solvent were then investigated, and the results showed that, under the optimized reaction conditions, i.e.,10 wt%concentration of HDC in DOS, 250 °C temperature, 60 min reaction time, 83.8% yield of HDI had been achieved over Zn–Co/ZSM-5. Decomposition of the intermediate hexamethylene-1-carbamate-6-isocyanate(HMI) over Zn–Co/ZSM-5 in DOS solvent was further studied and the results indicated that yield of HDI from HMI reached to 69.6%(98.6% HDI selectively) at 270 °C, which further increased the yield of the total HDI(HDI_(tol)) to as high as 95.0%. Recycling of catalyst showed that HDI and HMI yield slightly decreased, and by-product yield increased after the catalyst was reused for 4 times. At last possible reaction mechanism was proposed.

关键词： Non-phosgene Thermal decomposition Hexamethylene-1,6-diisocyanate Hexamethylene-1,6-dicarbamate Bimetallic supported ZSM-5 catalyst

Nonlinear Weighted Average and Blossoming

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

Communications in Mathematics and Statistics 2020年第3期8卷 361-378页

作者： Rongin Uwitije Xuhui Wang ammar Qarariyah Jiansong Deng School of Mathematical Sciences University of Science and Technology of ChinaHefei 230026AnhuiPeople’s Republic of China School of Mathematics Hefei University of TechnologyHefei 230009AnhuiPeople’s Republic of China

In this paper,we introduce a new averaging rule,the nonlinear weighted averaging *** an application,this averaging rule is used to replace the midpoint averaging in the de Casteljau evaluation algorithm and with this scheme we can also generate transcendental functions which cannot be generated by the classical de Casteljau *** also investigate the properties of the curves of the functions generated by blossoming,where the results show that these curves and the classical Bézier curves have some similar properties,including variation diminishing property and endpoint ***,the curves obtained by blossoming using nonlinear weighted averaging rules induced by certain functions violate some properties like convex hull property.

关键词： Nonlinear weighted averaging rule Midpoint averaging De Casteljau algorithm Bézier curves Blossoming

Artificial visual perception neural system using a solution-processable MoS_(2)-based in-memory light sensor

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

光:科学与应用(英文版) 2023年第8期12卷 1583-1594页

作者： Dayanand Kumar Lana Joharji Hanrui Li Ayman Rezk ammar Nayfeh Nazek El-Atab Smart Advanced Memory Devices and Applications(SAMA)LaboratoryElectrical and Computer Engineering ProgramComputer Electrical Mathematical Science and Engineering DivisionKing Abdullah University of Science and Technology(KAUST)Thuwal 23955Kingdom of Saudi Arabia Department of Electrical Engineering and Computer Science Khalifa UniversityAbu Dhabi 127788United Arab Emirates

Optoelectronic devices are advantageous in in-memory light sensing for visual information processing,recognition,and storage in an energy-efficient ***,in-memory light sensors have been proposed to improve the energy,area,and time efficiencies of neuromorphic computing *** study is primarily focused on the development of a single sensing-storage-processing node based on a two-terminal solution-processable MoS2 metal-oxide-semiconductor(MOS)charge-trapping memory structure—the basic structure for charge-coupled devices(CCD)—and showing its suitability for in-memory light sensing and artificial visual *** memory window of the device increased from 2.8 V to more than 6V when the device was irradiated with optical lights of different wavelengths during the program ***,the charge retention capability of the device at a high temperature(100 ℃)was enhanced from 36 to 64%when exposed to a light wavelength of 400 *** larger shift in the threshold voltage with an increasing operating voltage confirmed that more charges were trapped at the Al_(2)O_(3)/MoS_(2) interface and in the MoS_(2) layer.A small convolutional neural network was proposed to measure the optical sensing and electrical programming abilities of the *** array simulation received optical images transmitted using a blue light wavelength and performed inference computation to process and recognize the images with 91%*** study is a significant step toward the development of optoelectronic MOS memory devices for neuromorphic visual perception,adaptive parallel processing networks for in-memory light sensing,and smart CCD cameras with artificial visual perception capabilities.

关键词： visual neural process