检索结果-内蒙古大学图书馆

INTEGRAL-EQUATION FORMULATION OF RADIATION FROM RECTANGULAR WAVE-GUIDES AND HORNS

INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS 1994年第3期7卷 155-166页

作者： MOHEB, H SHAFAI, L Department of Electrical & Computer Engineering University of Manitoba Winnipeg Manitoba Canada R3T 2N2 Lotfoilah Shafai (S'67-M'69-SM'75-F'88) was born in Maragheh Iran in 1941. He received the B.Sc. degree from the University of Tehran Iran and the M.Sc. and Ph.D. degrees from the University of Toronto Toronto Ontario Canada in 1966 and 1969 respectively all in electrical engineering. Since 1969 he has been with the Electrical Engineering Department of the University of Manitoba where he is currently a Professor and holder of the Electromagnetic Chair. The period July 1976 to January 1977 he spent at the Communication Research Centre Ottawa Canada as a Research Scientist and he contributed to the design of the low-cost earth station antenna for the Hermes satellite. From January 1977 to July 1977 he was with the Electromagnetics Institute of the Technical University of Denmark as a Visiting Professor and conducted research on the modelling of corrugated horns for the European Space Agency. His main research interests are in applied electromagnetics antennas and computer-aided design. He is the recipient of numerous awards the most recent ones include the University of Manitoba Merit Award in Research 1987 and 1989 Sigmaxi Senior Scientist Award 1989 and Maxwell Premium Award (IEE) 1990.

The radiation field patterns of rectangular waveguides and horns of finite dimensions are obtained numerically. The electric field integral equation is formulated to relate their radiation patterns to the surface current distribution. These currents are determined numerically by reducing the integral equation to a matrix equation, using the moment method. The computed currents are then used to calculate the radiation patterns and cross-polar fields of the finite waveguides and horns. The method is numerically efficient and can be applied to the computation and optimization of the antenna feed configurations.

关键词： Directional patterns (antenna)

来源：评论

学校读者我要写书评

暂无评论

USING VIRTUAL ENVIRONMENTS IN THE design OF SHIPS

引用

NAVAL ENGINEERS JOURNAL 1994年第3期106卷 91-106页

作者： JONS, OP RYAN, JC JONES, GW Otto P. Jons:received a Diplom Ing. in shipbuilding from the Technical University of Hanover W. Germany and an MS in naval architecture and marine engineering from MIT. He then joined Litton Ship Systems where he was responsible for the preliminary design of the DD-963 hull structure and then for ship system integration as manager LHA ship systems engineering department. From 1972 to 1974 he was the principal research scientist at Hydronautics. In 1974 as technical director he helped establish the Crystal City office of Designers and Planners. Mr. Jons was one of the co-founders of Advanced Marine Enterprises Inc. in 1976 where he serves as corporate vice president engineering. J. Christopher Ryan:earned his bachelors and masters degrees in naval architecture from Webb Institute and MIT respectively. He spent three years at the advanced marine technology division of Litton Industries working on the DD-963 class ship design and related computer aided design projects. He subsequently went to the Navy Department concentrating on early stage design of surface combatants for twelve years including work on the FFG-7 Sea Control Ship CSGN and CVV aircraft carrier projects. He then shifted focus and became the Technical Director for the Computer Supported Design Program in NavSea for five years. Mr. Ryan has served in several supervisory positions within the Ship Design Group in NavSea since that time. He is currently the director of the future ship concepts division. Gary W. Jones:graduated from the University of Tennessee in 1971 with a BS in mechanical engineering and followed up with graduate work at George Washington University and the University of Maryland. Mr. Jones was with the Naval Sea Systems Command from 1971 until 1988 where he was a naval architect in the submarine section of the hull form design division. In 1988 he was detailed to the Defense Advanced Research Projects Agency (DARPA) where he became the program manager for the advanced submarine technology program's hydrodynamic hydroac

A major contributor to the expense and length of time to design, build, and test new systems has been the need to build and test hardware prototypes to determine their effectiveness in meeting operational requirements. Recent and dramatic advances in computer simulation technologies hold forth the promise of revolutionizing design and acquisition strategies by providing the means to validate end users' requirements prior to hardware construction. By designing and operationally testing virtual prototypes in a virtual environment, these technologies will soon offer naval architects the ability to build and launch ships in computer-based cyberspace in lieu of the shipbuilder's ways. The authors of this paper provide the background for these developments, explore the significance and ramifications of these technologies to the current process of ship and system design, outline challenges lying ahead, and present their vision and recommendations for future development.

关键词：

来源：评论

学校读者我要写书评

暂无评论

An investigation into mathematical models of optimal tolerancing supporting concurrent engineering

An investigation into mathematical models of optimal toleran...

引用

ASME 1993 International computers in engineering Conference and Exposition, CIE 1993

作者： Zhang, Genbao Porchet, Michel Department of Mechanical Engineering Computer-Aided Design Laboratory Swiss Federal Institute of Technology Lausanne Switzerland

ISBN: (纸本)9780791897645

This paper presents a new tolerance design theory — simultaneous tolerancing which works in the concurrent engineering context. After the necessity to develop a simultaneous tolerancing theory is stated, by showing the shortcomings of conventional tolerancing technique, the concept of simultaneous tolerancing is given, and its elements are briefly presented. Then we focus our attention on the development of a general mathematical model of optimal tolerancing supporting concurrent engineering. Two commonly used models, worst-case and statistical, are discussed in detail. Next, a method of "interim tolerances", which help to determine an appropriate machining process without using functional tolerances, is proposed. The simultaneous tolerancing theory presented in this paper permits of determining directly optimal machining tolerances in product design, reducing the manufacturing cost and improving the quality of products. © 1993 ASME 1993 International computers in engineering Conference and Exposition, CIE 1993. All rights reserved.

关键词： Fits and tolerances

来源：评论

学校读者我要写书评

暂无评论

The study of a multi-component system using a complete cad software package

The study of a multi-component system using a complete cad s...

引用

ASME 1993 International computers in engineering Conference and Exposition, CIE 1993

作者： Lewis, Burton Computer-Aided Design Laboratory Department of Mechanical Engineering Swiss Federal Institute of Technology Lausanne Switzerland

ISBN: (纸本)9780791897645

When performing a complete study on the design of a multi-component system of at least two components, can a CAD software perform to expectations, that is, can we do a complete study on the entire multi-component system including bearing analysis for the contact between rotating components, and simple interference checks? In this paper, I will describe simple steps and precautions to take when doing a study on the design and performance of a multi-component system using a complete CAD package - including a Drafting module, a Solid Modeler, and a Finite Element Analysis module. I will use an example of a system of multiple rotating arms to show that from a 2-D blueprint, using the drafting module, we can enter the complete geometry of each arm separately, then pass on to the solid modeler. Once the solid 3-D model is constructed, we can transfer the model onto the finite element analysis module of the CAD package and test the model. After the model satisfies all requirements, we can come back to the solid modeler and check the "modified" version of the model by updating the previous solid model. If all is well at this point, then we can move on to the superposition of the 3-D solid model into a 2-D version to perform tolerance analysis. After tolerance analysis, we can move on to the final stage which is to update the 2-D drafting version adding the tolerances recently obtained. This is a general outline and should be straight forward except for the problems that we could encounter especially in the solid modeler and the finite element analysis module. The study or design principals of a multi-component system is not the subject of this paper, but how to perform such a study using all the available modules of a CAD package. There are few complete CAD packages on the market today that allow such a study, but transferring data, whether it is of finite elements, solid models, or 2-D geometry, is much easier today using a variety of different types of transfer files. Som

关键词： computer aided design

来源：评论

学校读者我要写书评

暂无评论

Experimental Validation of a Performance Model for Simple Layered Task Systems

Experimental Validation of a Performance Model for Simple La...

引用

1993 International Conference on Parallel Processing, ICPP 1993

作者： Tayyab, Athar B. Kuhl, Jon G. Center for Computer Aided Design Department of Electrical and Computer Engineering University of Iowa Iowa CityIA52242 United States

ISBN: (纸本)0849389836

Performance modeling for the class of parallel computa tions structured as simple layered task systems is consid ered. Specifically studied are the effects of using different forms of inter-layer sequencing mechanisms. The paper refines and generalizes an earlier analytical performance model and presents the results of experimental validation of the model on two different multiprocessor systems. The experimental validation results show that the model is quite accurate, with average prediction errors in the range of only a few percent. Finally, the paper uses the model to investigate performance tradeoff issues for lay ered task systems using barrier versus explicit intertask sequencing mechanisms and implemented on computing systems with differing architectural features. This study shows that the relationship between the type of sequenc ing mechanism, the nature of the computation, and the features of the underlying architecture, interact in com plex ways to impact overall performance. Several inter esting and non-intuitive results are shown. © 1993 IEEE.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Spline based design of cam contours for improved dynamic performance

Spline based design of cam contours for improved dynamic per...

引用

ASME 1993 International computers in engineering Conference and Exposition, CIE 1993

作者： Ault, Holly K. Wilkinson, James C. Department of Mechanical Engineering Computer Aided Design Laboratory Worcester Polytechnic Institute WorcesterMA United States

ISBN: (纸本)9780791897645

A method for the integrated design and manufacture of radial plate cams is discussed. Currently, a cam-follower system is designed by specifying constraints on the motion of the follower. The physical cam contour or cam pitch curve are not mathematically defined. The cam is manufactured from the discretized follower motion program. A new method for cam design is proposed which will produce a smooth, mathematically defined cam pitch curve while maintaining the proper constraints on the follower motion. Piecewise polynomial functions in the form of rational and/or non-rational splines may be used. Cams will be manufactured using smoothed profiles and tested for improved dynamic performance. The results of initial investigations of cam profile design for this research are presented. © 1993 ASME 1993 International computers in engineering Conference and Exposition, CIE 1993. All rights reserved.

关键词： Gas turbines

来源：评论

学校读者我要写书评

暂无评论

Structural synthesis under manufacturability constraints: A CAD system for the design of injection-molded product housings

引用

Research in engineering design 1993年第3-4期5卷 185-201页

作者： Dighe, Rahul Jakiela, Mark J. Wallace, David R. Computer-Aided Design Laboratory Department of Mechanical Engineering Massachusetts Institute of Technology Cambridge 02139 MA Room 3-461a United States

We describe a computer-aided design system that automatically constructs the internal functional surface shapes of plastic injection molded product housings. Fundamental manufacturability constraints related to the geometry of injection mold parting and the solidification of molten plastic are identified. These constraints are embodied in structural synthesis operators that create the internal shapes given a set of functional requirements. An implementation, which is integrated with a system that automatically designs the external visible surface of the housing, is discussed. Algorithms for the structural synthesis operators are provided along with sample output demonstrating their operation. © 1993 Springer-Verlag London Limited.

关键词： computer-aided design design for manufacture Injection molding Structural synthesis

来源：评论

学校读者我要写书评

暂无评论

A Methodology to Support Concurrent engineering in a Simulated Process Evaluation Environment (SPREE)

引用

Concurrent engineering 1993年第4期1卷 193-201页

作者： Yetukuri, Nagarjun V. Prescott, William C. Fischer, Gary W. Department of Industrial Engineering The University of Iowa Iowa City Iowa 52242 4108 EB United States Computer-aided Design Software Inc. (CADSI) Coralville lowa 52241 2651 Crosspark Road United States

This paper describes a methodology to support concurrent engineering in a simulated process evaluation environment (SPREE) for path- directed robot (PDR) applications, such as gas metal arc welding, spray painting, and adhesive applications. Such an environment makes it possible to program PDR applications off-line more accurately. The methodology includes consideration of the process variables and their constraints, design constraints, and robot specifications. SPREE allows the user to evaluate the process plan against process constraints and robot specifications, perform robot motion analysis, and evaluate the performance of the robot;thus, the user is able to complete the front-end preparations in SPREE, so that the off-line program for the selected robot can be generated in an environmental external to SPREE. © 1993, Sage Publications. All rights reserved.

关键词： concurrent engineering dynamic analysis gas metal arc welding off-line programming process evaluation simulation

来源：评论

学校读者我要写书评

暂无评论

Experimental Validation of a Performance Model for Simple Layered Task Systems

Experimental Validation of a Performance Model for Simple La...

引用

International Conference on Parallel Processing (ICPP)

作者： Athar B. Tayyab Jon G. Kuhl Center for Computer Aided Design and Department of Electrical & Computer Engineering University of Iowa Iowa IA USA

关键词： Predictive models Concurrent computing Analytical models Costs Parallel processing Performance analysis Multiprocessing systems computational modeling design engineering Cities and towns

来源：评论

学校读者我要写书评

暂无评论

CAD procedures for planar re-entrant type couplers and three-line baluns

CAD procedures for planar re-entrant type couplers and three...

引用

Microwave, MTT-S International Symposium

作者： C.M. Tsai K.C. Gupta Center of Microwave and Millimeter-Wave Computer Aided Design Department of Electrical and Computer Engineering University of Colorado Boulder CO USA

A generalized network model for coupled multiconductor transmission lines is derived based on normal mode parameters. The model is used in the design of planar re-entrant type couplers. By using this network model, the design of a planar re-entrant coupler can be derived from the design of a traditional two-line coupler. The design procedure for single-layer planar baluns using three-conductor transmission lines has also been developed based on this network model. design procedures and examples are presented.< >

关键词： Couplers Impedance matching Transmission line matrix methods Coupling circuits Planar transmission lines Coaxial components Conductors Multiconductor transmission lines Voltage Microstrip

来源：评论

学校读者我要写书评

暂无评论

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

请选择保存的检索档案：

请选择收藏分类：

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

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

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：