检索结果-南通市图书馆

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

电气化铁路混合储能系统的控制策略研究

电气化铁路混合储能系统的控制策略研究

作者： muhammad Ibrar younas（于乃思）北京交通大学

学位级别：硕士

近年来,气候变化与环境可持续发展在世界各地得到了广泛的关注。电气化铁路的飞速发展有效减少了碳排放,在交通运输方式中占据重要地位。由于列车在制动过程中优先采用再生制动,会产生大量的再生制动能量。这些能量包含谐波及负序分量,... 详细信息

近年来,气候变化与环境可持续发展在世界各地得到了广泛的关注。电气化铁路的飞速发展有效减少了碳排放,在交通运输方式中占据重要地位。由于列车在制动过程中优先采用再生制动,会产生大量的再生制动能量。这些能量包含谐波及负序分量,给电网带来了严重的电能质量问题,直接影响了铁路部门的经济效益。发展带有储能技术的电气化铁路,合理利用再生制动能量是改善运行经济性、节约能源的有效方法。本文提出了一种采用铁路功率调节器(Railway Power Conditioner,RPC)与混合储能系统相结合的电气化铁路再生制动能量存储方案,着重对其控制策略进行研究,对提高电气化铁路再生制动能量利用率,降低铁路运营成本具有十分重要的意义。首先,研究了再生制动能量利用的必要性并针对牵引负荷特点确定了系统再生制动能量容量级别。对比分析了基于能量消耗、牵引变电所储能、10k V电力馈能、基于RPC的电气化铁路再生能利用技术。对各种储能技术从原理、适用场景、经济性等方面进行了评估,最终确定了采用蓄电池与超级电容储能技术相结合的混合储能方案。其次,分析了RPC的工作原理并构建了RPC的等效数学模型。对双向DC/DC变换器的拓扑结构进行了分析,研究了Buck/Boost电路的双向DC/DC变换器工作原理。根据供电臂能量流动情况,分析了牵引变电所两侧能量传输特性。为实现两供电臂能量流通和电能质量提升,进一步研究了RPC优化控制策略,在分析负序、谐波补偿方法的基础上,提出RPC优化补偿控制方法。最后,提出了一种基于阈值检测的顶层能量管理控制策略,以实现蓄电池与超级电容储能介质技术特性互补。在考虑蓄电池“浅充浅放”前提下,基于滑动平均滤波理论设计了限幅功率动态调整内部协调控制方法。在MATLAB/Simulink中搭建仿真模型,结果表明该方案在实现再生制动能量回收利用的同时提升了电能质量,从而验证了基于RPC架构的混合储能系统应用于铁路大功率再生能场景的可行性。

关键词：再生制动混合储能系统铁路功率调节器电能质量能源管理系统双向DC/DC变换器

An Abstractive Summarization Technique with Variable Length Keywords as per Document Diversity

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

Computers, Materials & Continua 2021年第3期66卷 2409-2423页

作者： muhammad Yahya Saeed muhammad Awais muhammad younas muhammad Arif Shah Atif Khan M.Irfan Uddin Marwan Mahmoud Department of Software Engineering Government College UniversityFaisalabadFaisalabad38000Pakistan Department of IT and Computer Science Pak-Austria Fachhochschule Institute of Applied Sciences and TechnologyHaripurPakistan Department of Computer Science Islamia College PeshawarPeshawarPakistan Institute of Computing Kohat University of Science and TechnologyKohatPakistan Faculty of Applied Studies King Abdulaziz UniversityJeddahSaudi Arabia

Text Summarization is an essential area in text mining,which has procedures for text *** natural language processing,text summarization maps the documents to a representative set of descriptive ***,the objective of text extraction is to attain reduced expressive contents from the text *** summarization has two main areas such as abstractive,and extractive *** text summarization has further two approaches,in which the first approach applies the sentence score algorithm,and the second approach follows the word embedding *** such text extractions have limitations in providing the basic theme of the underlying *** this paper,we have employed text summarization by TF-IDF with PageRank keywords,sentence score algorithm,and Word2Vec word *** study compared these forms of the text summarizations with the actual text,by calculating cosine ***,TF-IDF based PageRank keywords are extracted from the other two extractive *** intersection over these three types of TD-IDF keywords to generate the more representative set of keywords for each text document is *** technique generates variable-length keywords as per document diversity instead of selecting fixedlength keywords for each *** form of abstractive summarization improves metadata similarity to the original text compared to all other forms of summarized *** also solves the issue of deciding the number of representative keywords for a specific text *** evaluate the technique,the study used a sample of more than eighteen hundred text *** abstractive summarization follows the principles of deep learning to create uniform similarity of extracted words with actual text and all other forms of text *** proposed technique provides a stable measure of similarity as compared to existing forms of text summarization.

关键词： Metadata page rank sentence score word2vec cosine similarity This

Advanced Study of Unsteady Heat and Chemical Reaction with Ramped Wall and Slip Effect on a Viscous Fluid

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 Theoretical Physics 2017年第3期67卷 301-308页

作者： Ayesha Sohail K.Maqbool Noreen Sher Akbar muhammad younas Department of Mathematics COMSATS Institute of Information technology Lahore Pakistan Department of Mathematics & Statistics FBAS IIU Islamabad 44000 Pakistan DBS&H CEME National University of Sciences and DBS&H CEME National University of Sciences and Technology Islamabad Pakistan

This paper investigate the effect of slip boundary condition, thermal radiation, heat source, Dufour number,chemical reaction and viscous dissipation on heat and mass transfer of unsteady free convective MHD flow of a viscous fluid past through a vertical plate embedded in a porous media. Numerical results are obtained for solving the nonlinear governing momentum, energy and concentration equations with slip boundary condition, ramped wall temperature and ramped wall concentration on the surface of the vertical plate. The influence of emerging parameters on velocity,temperature and concentration fields are shown graphically.

关键词：粘性流体化学反应滑移效应非稳态滑移边界条件壁面浓度场流体流动

巴基斯坦默拉直流工程频率控制器设计及实际特性分析

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

电力系统自动化 2023年第2期47卷 173-180页

作者：常勇吕鹏飞刘宇徐凯谢岩孙天甲 muhammad Waseem younas 国家电网有限公司北京市100031 中国电力技术装备有限公司北京市100052 中国电力科学研究院有限公司北京市100192 国网上海市电力公司上海市200122 巴基斯坦国家输配电公司巴基斯坦拉合尔54000

巴基斯坦默拉直流投运后已经成为该国电网骨干输电通道,为帮助电网故障或非故障解列后维持稳定,默拉直流配置了频率控制器。文中从巴基斯坦电网稳定特性分析出发,提出一种基于仿真和实测相结合的频率控制器设计方法;主张应针对电网实际... 详细信息

巴基斯坦默拉直流投运后已经成为该国电网骨干输电通道,为帮助电网故障或非故障解列后维持稳定,默拉直流配置了频率控制器。文中从巴基斯坦电网稳定特性分析出发,提出一种基于仿真和实测相结合的频率控制器设计方法;主张应针对电网实际稳定需求并考虑送、受端电网承载能力进行频率控制器设计;总结了频率控制器的动作门槛设计方法、调制限值确定原则和控制器退出原则;分析了实际电网解列事件中频率控制器的动作特性;给出直流输电附加控制的技术基础及设计使用原则。强调直流附加控制应综合考虑交流电网稳定控制需求及实际电网特性,进行定制化设计,以期为后续交直流电网协同发展提供参考。

关键词：交直流混联电网频率控制器直流输电控制保护直流附加控制

Liver-Tumor Detection Using CNN ResUNet

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

Computers, Materials & Continua 2021年第5期67卷 1899-1914页

作者： muhammad Sohaib Aslam muhammad younas muhammad Umar Sarwar muhammad Arif Shah Atif Khan MIrfan Uddin Shafiq Ahmad muhammad Firdausi Mazen Zaindin Department of Computer Science Government College University FaisalabadFaisalabad38000Pakistan Department of IT and Computer Science Pak-Austria Fachhochschule Institute of Applied Sciences and TechnologyHaripur22620Pakistan Department of Computer Science Islamia College PeshawarPeshawarKPPakistan Institute of Computing Kohat University of Science and TechnologyKohatPakistan Department of Industrial Engineering College of EngineeringKing Saud UniversityRiyadh11421Saudi Arabia Department of Statistics and Operations Research College of ScienceKing Saud UniversityRiyadh11421Saudi Arabia

Liver tumor is the fifth most occurring type of tumor in men and the ninth most occurring type of tumor in women according to recent reports of Global cancer statistics *** are several imaging tests like Computed Tomography(CT),Magnetic Resonance Imaging(MRI),and ultrasound that can diagnose the liver tumor after taking the sample from the tissue of the *** tests are costly and *** paper proposed that image processing through deep learning Convolutional Neural Network(CNNs)ResUNet model that can be helpful for the early diagnose of tumor instead of conventional *** existing studies have mainly used the two Cascaded CNNs for liver segmentation and evaluation of Region Of Interest(ROI).This study uses ResUNet,an updated version of U-Net and ResNet Models that utilize the service of Residential *** apply over method on the 3D-IRCADb01 dataset that is based on CT slices of liver tumor affected *** results showed the True Value Accuracy around 99%and F1 score performance around 95%.This method will be helpful for early and accurate diagnose of the Liver tumor to save the lives of many patients in the field of Biotechnology.

关键词： Liver tumor diagnose ResUNet CNNs segmentation

Automated Test Case Generation from Requirements: A Systematic Literature Review

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 2021年第5期67卷 1819-1833页

作者： Ahmad Mustafa Wan M.N.Wan-Kadir Noraini Ibrahim muhammad Arif Shah muhammad younas Atif Khan Mahdi Zareei Faisal Alanazi Department of Software Engineering School of ComputingUniversiti Teknologi Malaysia Johor BahruJohor81310Malaysia Department of Computer Science Government College UniversityFaisalabad38000Pakistan Department of Software Engineering Pak-Austria Fachhochschule Institute of Applied Sciences and TechnologyHaripur22620Pakistan Department of Computer Science Islamia College PeshawarPeshawarPakistan Tecnologico de Monterrey School of Engineering and SciencesZapopan45201Mexico Department of Electrical Engineering Prince Sattam Bin Abdulaziz UniversityAl Kharj11942Saudi Arabia

Software testing is an important and cost intensive activity in software *** major contribution in cost is due to test case ***-based testing is an approach in which test cases are derivative from requirements without considering the implementation’s internal ***-based testing includes functional and nonfunctional *** objective of this study is to explore the approaches that generate test cases from requirements.A systematic literature review based on two research questions and extensive quality assessment criteria includes *** study identies 30 primary studies from 410 studies spanned from 2000 to *** review’s nding shows that 53%of journal papers,42%of conference papers,and 5%of book chapters’address requirementsbased *** of the studies use UML,activity,and use case diagrams for test case generation from *** of the signicant lessons learned is that most software testing errors are traced back to errors in natural language requirements.A substantial amount of work focuses on UML diagrams for test case generations,which cannot capture all the system’s developed ***,there is a lack of UML-based models that can generate test cases from natural language requirements by rening them in *** criteria indicate how efciently the testing has been performed 12.37%of studies use requirements coverage,20%of studies cover path coverage,and 17%study basic coverage.

关键词： Test case generation functional testing techniques requirementsbased test case generation system testing natural language requirement requirements tractability coverage criteria

Identification of microRNAs in ecological model plant <i>Mimulus</i>

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 Biophysical Chemistry 2011年第3期2卷 322-331页

作者： muhammad younas Khan Barozai muhammad Din Iftikhar Ahmed Baloch Department of Botany University of Baluchistan Sariab Road Quetta. Pakistan

MicroRNAs (miRNAs) are small, non-coding and regulatory RNAs about 20 to 24 nucleotides long. Their conserved nature among the various organisms makes them a good source of new miRNAs discovery by comparative genomics approach. This study resulted in 34 miRNAs belonging to 21 families in ecological model plant Mimulus. All the miRNA families (mir 156, 157, 159, 160, 164, 172, 319, 393, 395, 397, 399, 400, 403, 417, 419, 472, 782, 854, 858, 867 and 2112) are found for the first time in Mimulus. The MIR-399 is found as precursor miRNA cluster with 4 mature sequences. All 34 miRNA precursors form stable minimum free energy stem loop structure as their orthologues form and the mature miRNAs reside in the stem portion of the stem loop structure. Twenty eight are from Mimulus guttatus and six miRNAs belong to Mimulus lewisii. Their targets consist of dihy-droflavonol-4-reductase, cycloidea-like protein, DNA-directed RNA polymerase II, maturase (matR) and transcription factors like;squamosa-promoter binding, MYB, palmate-like pentafoliata 1.

关键词： Keywords: Comparative Genomics MicroRNAs Mimulus

黑龙江省水稻恶苗病菌对氰烯菌酯敏感性及其对咪鲜胺抗性风险评估

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

黑龙江省水稻恶苗病菌对氰烯菌酯敏感性及其对咪鲜胺抗性风险评估

Appraisal of MsepCSP14 for chemosensory functions in Mythimna separata

中国植物病理学会2017年学术年会

作者： muhammad Waqas younas 彭钦刘莹刘西莉中国农业大学植物病理学系

水稻恶苗病是黑龙江省水稻产区的常见毁灭性病害,引起该病害的主要病原菌为Fusarium fujikuroi。2013—2015年,该病害在黑龙江省尤为严重,对水稻生产造成了极大威胁。本研究测定了分离自黑龙江地区水稻样本上的恶苗病菌对新型杀菌剂氰... 详细信息

水稻恶苗病是黑龙江省水稻产区的常见毁灭性病害,引起该病害的主要病原菌为Fusarium fujikuroi。2013—2015年,该病害在黑龙江省尤为严重,对水稻生产造成了极大威胁。本研究测定了分离自黑龙江地区水稻样本上的恶苗病菌对新型杀菌剂氰烯菌酯的敏感性,评估了水稻恶苗病菌对咪鲜胺的抗性风险,为田间生产中进行抗药性监测和寒冷地区水稻恶苗病的防治提供科学参考。首先采用菌丝生长速率法,测定了采自黑龙江地区的95株水稻恶苗病菌对氰烯菌酯的敏感性。结果表明:供试水稻恶苗病菌对氰烯菌酯的EC分布于0.031 7.717μg/mL,平均EC值为0.274±0.210μg/mL。获得的水稻恶苗病菌对氰烯菌酯的敏感性频率分布呈单峰曲线,未发现敏感性下降的亚群体。因此,可将其作为水稻恶苗病菌对氰烯菌酯的敏感性基线,该结果为田间抗药性监测提供了参考和依据。通过鉴别浓度和EC测定方法,检测了95株水稻恶苗病菌对咪鲜胺的敏感性,结果表明:6株水稻恶苗病菌对咪鲜胺表现为敏感,其余89株病原菌均对咪鲜胺表现为抗性,抗性频率达到93.6%。生物学性状研究表明,部分抗性菌株的菌丝生长速率、产孢能力和分生孢子萌发率发生了显著变化,抗性菌株的分生孢子产量稍低于敏感菌株,但抗性菌株菌的致病力显著高于敏感菌株。交互抗药性研究结果表明:咪鲜胺与氰烯菌酯、种菌唑、戊唑醇、多菌灵和氟吡菌酰胺之间没有交互抗药性。结合抗性菌株的分离频率和生存适合度研究结果,综合评估黑龙江省水稻恶苗病菌对咪鲜胺具有中-高等抗性风险。

关键词：水稻恶苗病菌敏感性抗性风险评估

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Insect Science 2022年第1期29卷 162-176页

作者： Aneela younas muhammad Irfan Waris muhammad Shaaban muhammad Tahir ul Qamar Man-Qun Wang College of Plant Science and Technology Huazhong Agricultural UniversityWuhanChina Department of Soil Science Faculty of Agricultural Sciences and TechnologyBahauddin Zakariya UniversityMultanPakistan State Key Laboratory of Conservation and Utilization of Subtropical Agro-bioresources College of Life Science and TechnologyGuangxi UniversityNanning530005China

Chemosensory proteins (CSPs) have great contributions in performing diverse functions in insects. However, physiological appraisal of chemosensory protein genes still remains elusive in insects. We studied expression patterns and binding affinities of MsepCSP14, a chemosensory protein, in Mythimna separata. The distinct functions of MsepCSP14 were validated by employing different molecular techniques. The MsepCSP14 had high resemblance of sequence with chemosensory proteins of other insect family members. The MsepCSP14 expression was higher in antennal tissues of females than other tissues. Fluorescence binding assay validated that binding of nine out of 21 ligands to MsepCSP14 was higher at pH 7.4 than at pH 5.0. Three dimensional modeling (3D) and docking analysis predicted that amino acid residues of MsepCSP14 were involved in binding of compounds, and behavior assay displayed that adults of M. separata considerably responded to four volatiles from compounds demonstrating strong binding ability to MsepCSP14. Results of the present study suggest that MsepCSP14 is likely to mediate chemosensory functions in M. separata.

关键词： chemoreception expression pattern fluorescent binding olfaction oriental army worm Y-tube