检索结果-南通市图书馆

Digital modulation classification using multi-layer perceptron and time-frequency features

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2007年第2期18卷 249-254页

作者： Yuan Ye Mei Wenbo dept. of Industrial design and Information Engineering Beijing Institute of Clothing Technology Beijing 100029 P. R. China dept. of Electronic Engineering Beijing Inst. of Technology Beijing 100081 P. R. China

Considering that real communication signals corrupted by noise are generally nonstationary, and timefrequency distributions are especially suitable for the analysis of nonstationary signals, time-frequency distributions are introduced for the modulation classification of communication signals： The extracted time-frequency features have good classification information, and they are insensitive to signal to noise ratio （SNR） variation. According to good classification by the correct rate of a neural network classifier, a multilayer perceptron （MLP） classifier with better generalization, as well as, addition of time-frequency features set for classifying six different modulation types has been proposed. Computer simulations show that the MLP classifier outperforms the decision-theoretic classifier at low SNRs, and the classification experiments for real MPSK signals verify engineering significance of the MLP classifier.

关键词： Digital modulation classification Time-frequency feature Time-frequency distribution Multi-layer perceptron.

Statics of space syntax:Analysis of daylighting

在线全文

学校读者我要写书评

暂无评论

Frontiers of Architectural Research 2019年第3期8卷 311-318页

作者： Khaled Tarabieh Khaled Nassar Mahmoud Abdelrahman Islam Mashaly Architecture dept. American University in CairoNew Cairo 11835Egypt Construction Engineering dept. American University in CairoNew Cairo 11835Egypt Department of Building School of Design and EnvironmentThe National University of SingaporeSingapore

Space syntax involves a set of techniques for analyzing the spatial configurations of various spaces at building and urban *** spaces,such as prayer halls,are exam ples of buildings where observers experience space mostly from a single point of ***,traditional space syntax is mainly used in the analysis of visibility and space cognition in terms of isovists and graph-based *** other aspects of space cognition,such as day lighting,artificial lighting,and glare,are carried in the isolation of the space syntax *** paper proposes the scaling of the space syntax field for the inclusion of other parameters,such as daylighting,and integration of the associated performative measures to space syntax analysis of the mosque typology to aid in the studying of overall space cognition based on com fort and environmental *** present a case study on a typical mosque layout using m ulti-objective optim *** analysis presented in the paper has im plications for the architectural designs of spaces with respect to glare m anagem ent and daylight ***,it is unique and builds on our previous work for the exploration of comfort,visibility,and proximity thresholds for stationary observers.

关键词： Space syntax Daylighting Mosque Cognition Multi-objective optimization Genetic algorithms(GA)

Groundwater Waves in a Coastal Fractured Aquifer of the Third Phase Qinshan Nuclear Power Engineering Field

在线全文

学校读者我要写书评

暂无评论

Journal of Shanghai Jiaotong university(Science) 2005年第4期10卷 441-445页

作者：周念清唐益群唐和平 dept. of Geotechnical Eng. Tongji Univ. Shanghai 200092 China No.4 Research and design Inst. of Nuclear Industry Shijiazhuang 050021

Tidal fluctuations of Hangzhou Bay produce progressive pressure waves in adjacent field fractured aquifers, as the pressure waves propagate, groundwater levels and hydraulic gradients continuously fluctuate. The effect of tidal fluctuations on groundwater flow can be determined using the mean hydraulic gradient that can be calculated by comparing mean ground and surface water *** fluctuation is shown to affect the piezometer readings taken in a nearshore fractured aquifer around the nuclear power engineering field. Continuous monitoring of a network of seven piezometers provided relations between the tidal cycle and the piezometer readings. The relations can be expressed in times of a time and amplitude scaling factor. The time lag and the tidal efficiency factor and wavelength are calculated using these parameters. It provides significant scientific basis to prevent tide and groundwater for the nuclear power engineering construction and safety run of nuclear power station in the future.

关键词： tidal fluctuation fractured aquifer hydraulic gradient time lag tidal efficiency factor nuclear power engineering

Torque analysis for double-stator permanent-magnet motor

在线全文

学校读者我要写书评

暂无评论

Journal of Harbin Institute of Technology(New Series) 2002年第4期9卷 411-414页

作者：柴凤程树康崔淑梅 dept. of Electric Engineering

In addition to the characteristics of a conventional motor, a novel direct-drive double-stator permanent-magnet brushless motor proposed can operate in the state of either a generator or a motor as appropriate. Through numerical calculation and analysis, the output torque of double-stator permanent-magnet brushless motor of the same volume as the traditional machine is discussed, and the reduction of torque ripple by using the structure features of this motor is investigated. The results indicate that lower torque ripple under the condition of ideal effective torque can be obtained by the rational design of motor. The prototype motors tested show that this kind of motor structure has a higher power density.

关键词： direct-drive motor double-stator permanent-magnet motor

A novel combined baffle-cavity micro-combustor configuration for Micro-Thermo-Photo-Voltaic applications

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2020年第2期28卷 403-413页

作者： E.Amani A.Daneshgar A.Hemmatzade Mechanical Engineering dept. Amirkabir University of TechnologyTehranIran

The major issues of Micro-Thermo-Photo-Voltaic(MTPV) micro-combustors are flame instabilities, which narrow the operational range, and non-uniform wall temperature, which lowers the overall efficiency. The purpose of the present research is to propose a novel micro-combustor with combined baffle and cavity configuration to address these issues. For this aim, a numerical modeling approach is validated and used. The performance of the improved combustor is compared with another recent baffle-bluff configuration. It is shown that the novel design improves the average wall temperature by 36.4 K and mitigates its standard deviation by 13.4 K. Moreover, using the optimal baffle thickness, these enhancements can be augmented by 4% raise of average wall temperature, 62%increase of temperature uniformity, and 20% reduction in overall emission. The baffle length of 0.6 times the combustor length and thickness of 0.0625 times the baffle spacing result in the optimal operation due to the flame lift-off in the upstream direction. According to the sensitivity analysis, the most effective geometrical parameters are the baffle length and thickness. It is expected that using this novel micro-combustor with optimized design parameters improves the overall efficiency of MTPV systems.

关键词： Microscale Computational Fluid Dynamics(CFD) Reaction Micro-combustion Micro-Thermo-Photo-Voltaic(MTPV) Emission

Receding horizon H_∞ control for constrained time-delay systems

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2009年第2期20卷 363-370页

作者： Lu Mei Jin Chengbo Shao Huihe Inst. of Automation Shanghai Jiaotong Univ. Shanghai 200240 P. R. China dept. of Fieldbus Shanghai Automation Instrument Co. Ltd. Shanghai 200233 P. R. China dept. of Product design Shanghai Gaoke Valve Manufactory Co. Ltd. Shanghai 200092 P. R. China

A receding horizon Hoo control algorithm is presented for linear discrete time-delay system in the presence of constrained input and disturbances. Disturbance attenuation level is optimized at each time instant, and the receding optimization problem includes several linear matrix inequality constraints. When the convex hull is applied to denote the saturating input, the algorithm has better performance. The numerical example can verify this result.

关键词： receding horizon control Hoo control time-delay constrained input

Fractional Order Proportional Integral Derivative Controller design and Simulation for Bioengineering Systems

在线全文

学校读者我要写书评

暂无评论

Journal of Harbin Institute of Technology(New Series) 2013年第5期20卷 46-50页

作者： Wei-Cheng Fu Chun-Yang Wang Yao-Wu Shi Ying-Bin Sun dept. of Electronic and Information Engineering Changchun University of Science and Technology dept. of Communication Engineering Jilin University

This paper deals with the study of fractional order system tuning method based on Factional Order Proportional Integral Derivative( FOPID) controller in allusion to the nonlinear characteristics and fractional order mathematical model of bioengineering systems. The main contents include the design of FOPID controller and the simulation for bioengineering systems. The simulation results show that the tuning method of fractional order system based on the FOPID controller outperforms the fractional order system based on Fractional Order Proportional Integral( FOPI) controller. As it can enhance control character and improve the robustness of the system.

关键词： robustness bioengineering systems fractional order proportional integral derivative controller

On the Vibration Reduction Effect of Offshore Platform Vibration Distribution Structure

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 1996年第4期11卷 483-488页

作者： Chen Xueming , Li Longyuan Wang Qinjian Senior Engineer, dept. of Naval Arch, and Ocean Engineering, Shanghai Jiaotong University, 200030 Shanghai . Senior Engineer, Bohai Oil Engineering and design Company dept. of Nav. Arch. and Ocean Eng. Shanghai Jiaotong University 200030 Shanghai Bohai Oil Eng. and design Company

Based on the Bohai ocean environment characteristics, a new platform vibration distribution structure is designed to reduce the platform vibration due to flowing ice. The effect of the earthquake wave and ocean wave load on this vibration distribution structure is considered in the design. The principal idea of this new vibration distribution structure is dividing the platform main column into the inner tube and the outer tube. The outer tube is connected with the leg pontoon by braces, while the inner tube is used to support the platform deck. The inner tube and outer tube can be connected or disconneted in the region near the water line. For evaluating the vibration reduction effect of such a structure, tests are carried out on a steel model, and the external load of flowing ice, earthquake wave and ocean wave are simulated by concentated random load applied to different points of the model. The tests are performed in water media and air media respectively. The vibration reduction effect is evaluated by the transfer function of the vibration response at the measured points, and is presented by a dimensionless function dependent on the frequency. Test results show that this new vibration structure has an excellent vibration reduction effect.

关键词： offshore platform vibration mode transfer function

Circuit partition in ABC95 array computer based on FPGA

在线全文

学校读者我要写书评

暂无评论

Journal of Harbin Institute of Technology(New Series) 2000年第2期7卷 65-67页

作者：季振洲刘焕平曲云波 dept. of Computer Science and Engineering Harbin Institute of Technology Harbin 150001 China Harbin Artistic design Polytechnic School Harbin 150059 China

ABC95 array computer is an conflict free access array computer designed with FPGA based circuit partition and circuit integration. FPGA capacity and number of pins are used to judge the design quality. Experimental re... 详细信息

关键词： FPGA array computer VLSI layout