Implementing computer-aided design: the transition of nonusers

Prior research on the social impacts of computer-aided design (CAD) has treated nonusers, those still using manual methods, as control groups to which users are compared. The assumption is that nonusers' worklives are essentially unchanged by the implementation of CAD. It is argued that nonusers can also be affected by their organization's transition to CAD. It is hypothesized that CAD has primarily job-enhancing effects for the work lives of designers selected to use CAD and primarily negative effects for the work lives of nonusers, who might fear their manual skills would soon be obsolete. Data were collected in two large manufacturing firms through a survey of 74 CAD users and 30 nonusers and through a smaller number of interviews at each site. The results indicate that, compared with CAD users, nonusers were significantly older and spent more time on support and maintenance of old designs and relatively little time on conceptual design work and new design projects     

Managing change with CAD and CAD/CAM

A model is developed for the analysis of factors influencing organizational and technological changes associated with CAD and CAD/CAM (computer-aided design/computer-aided manufacture). Different pressures for adoption and the sociopolitical environment of the organization and related to managerial strategies and their impact on skills, tasks, training, and changes in work organization. Opportunities are illustrated through the experiences of seven British engineering companies implementing the technologies. Six of the companies are in manufacturing and one is an engineering services organization. Four of the companies are of small to medium size (under 500 employees) and the other three are large, multisite organizations. Key elements of the technological change are identified, and the position of the seven companies in relation to these elements is summarized and discussed     

CAD system use and engineering performance

Computer-aided design (CAD) systems can support engineering work at three levels: design, analysis, and communication. Seventy-five engineers in two gas turbine engine manufacturing companies were surveyed in an attempt to understand the relationship between these three types of CAD use and engineering performance. The results show strong links between different types of CAD use; use for design enables for for analysis, and 3-D system enables use of communication. Use of CAD communication features strongly relates to engineering performance. The results have implications for the design, implementation, management, and use of CAD systems     

基于标准单元布图模式的电源线/地线网络设计、优化和验证集成工具

介绍了一个基于标准单元布图模式的电源线/地线网络的辅助设计集成工具.它应用了一系列高效的算法,为用户提供了电源线/地线网络的设计、优化和验证的功能.非线性优化技术、分枝定界算法和不完全乔莱斯基分解的预优共轭梯度法是该工作的三个主体部分.用户可以选择使用非线性规划的方法或者几种分枝定界方法来满足他们对于精度和速度方面的不同需求.实验结果表明,文中所提供的算法可以在很快的运行速度下实现更低的布线资源占用.因此,在这些有效算法基础上实现的辅助设计工具具有处理大规模电路的能力.     

基于标准单元布图模式的电源线/地线网络设计、优化和验证集成工具

介绍了一个基于标准单元布图模式的电源线 /地线网络的辅助设计集成工具 .它应用了一系列高效的算法 ,为用户提供了电源线 /地线网络的设计、优化和验证的功能 .非线性优化技术、分枝定界算法和不完全乔莱斯基分解的预优共轭梯度法是该工作的三个主体部分 .用户可以选择使用非线性规划的方法或者几种分枝定界方法来满足他们对于精度和速度方面的不同需求 .实验结果表明 ,文中所提供的算法可以在很快的运行速度下实现更低的布线资源占用 .因此 ,在这些有效算法基础上实现的辅助设计工具具有处理大规模电路的能力.     

Managing CAD systems in mechanical design engineering

The results of an investigation into the management and use of CAD systems in ten manufacturing companies are reported. The goal of the research is to understand how engineers and managers perceive CAD systems, how work is restructured when CAD is used, and what barriers prevent the effective use of CAD systems. An introduction to CAD systems is presented, followed by a brief review of the latest literature relating to computer-aided design     

A user-centered approach to define high-level requirements fornext-generation CAD systems for mechanical engineering

The authors describe work undertaken within the Alvey Research Programme in the United Kingdom. They outline some of the user problems that have been discovered with CAD (computer-aided design) systems. These are then discussed in relation to the design process and, on the basis of studies of users, a less-structured, more opportunistic version of the mechanical engineering design process is described. The implications of this for the design of the CAD systems of the future, the intelligent systems are stated as global requirements, and a conceptual model based on a blackboard architecture is outlined which incorporates the requirements and allows articulation of their consequences. Finally, some as yet unanswered research questions are given     

Design, Debug, Deploy: The Creation of Configurable Computing Applications

Configurable Computing Machines (CCMs) are computing machines based on reconfigurable circuit technology such as field programmable gate-arrays. Early researchers recognized CCMs as a new, flexible, and powerful class of computer. The earliest CCMs featured rudimentary but significant integrated design, debug, and deployment (runtime) environments. This paper reviews those environments and the contributions they made and considers the progress made over the past 20 years in providing support for the “3 D’s” of configurable computing application development: design, debug, and deployment. It then introduces an integrated CAD framework for the creation of CCM CAD tools and describes a series of experiments in creating such a CAD tool suite — the JHDL system. The paper reviews lessons learned from that work and concludes by discussing the role integrated design, debug, and runtime environments will play in future CCM-based systems.     

利用CST微波工作室软件改进行波管的性能

计算机辅助设计（CAD）是设计行波管（TWT）的关键一步。本文介绍了利用CST微波工作室软件计算行波管慢波结构的色散和耦合阻抗的原理和方法。并用计算机模拟仿真行波管慢波结构冷特性，结合实际制管，提高了行波管的性能。     

A Formal Approach to On-Line Monitoring of Digital VLSI Circuits: Theory,Design and Implementation

This work is concerned with the development of algorithms and CAD tools for the design of digital circuits with on line monitoring capability. The Theory of Fault Detection and Diagnosis available in the literature on Discrete Event Systems has been adopted for on-line detection of stuck-at faults in Digital Circuits. Efficient computational techniques to deal with very large state spaces based on Ordered Binary Decision Diagrams and Abstraction have been proposed. Based on these a CAD tool has been developed that can provide a fully automated flow for design of circuits with on-line test capability without the requirement of any modification to the core. The tool can handle generic digital circuits with cell count as high as 15,000 and having the order of 2⁵⁰⁰ states. This is believed to be an improvement of an order of magnitude over results presented in the literature. This methodology enables the designer to tradeoff fault coverage and detection latency against area and power overhead. The design flow using the CAD tool developed is described and results for design of on-line detectors for various ISCAS89 benchmark circuits are provided. The methodology is further validated by design, fabrication, and testing of an ASIC in 0.18 μ technology.     

Computer-Aided Design for Low-Power Robust Computing in Nanoscale CMOS

This work argues that the foremost challenges to the continued rapid improvements in CMOS integrated circuit (IC) performance are power consumption and design robustness. Furthermore, these two goals are often contradictory in nature, which indicates that joint optimization approaches must be adopted to properly handle both. To highlight needs in computer-aided design (CAD), we review a sampling of state-of-the-art work in power reduction techniques, and also in the newly emerging area of statistical optimization applied to very large scale integration (VLSI) ICs. The lack of CAD techniques to perform multiobjective function optimization (specifically parametric yield under correlated performance metrics) is a major limitation of current CAD research. In addition, with design trends pushing towards architectures based on aggressive adaptivity and voltage scaling, CAD researchers and engineers will need to refocus efforts on enabling this type of complex design     

Happy medium [EMC CAD tools]

Electromagnetic compatibility is becoming an important element in the design of virtually all equipment and systems connected to an electrical supply. Contemporary design practice is increasingly reliant on the use of computer-based tools to realise the maximum degree of automation in the design process. This trend is set to continue. Furthermore, in the design of complex systems, interactions between different facets of the design problem make concurrent engineering practices mandatory. In practice, irrespective of its technical capabilities, ease of use and cost of deployment are critical factors in determining the success of any design tool. If a CAD package is to be widely used within industry then it must be both user friendly and capable of running quickly on modest PC platforms; at the same time, offering the user the maximum possible physical insight into the nature and magnitude of the interactions affecting the design. This article describes an approach to EMC CAD tool development, based on collaborative work between the universities of York and Nottingham, which is designed to meet these exacting requirements     

Study of the methods of calibration of the process OPC VT-5 models with a variable threshold

One of the most widely used approaches to simulation of complex lithographic systems is considered. The approach makes it possible to take into account the effect of the features of the manufacturing process on the transfer of very large-scale integration (VLSI) topology to a silicon wafer. The approach is based on the present-day aids for simulation and computer-aided design (CAD) of VLSI circuits and provides a means for reducing errors (that arise from the imperfection of the manufacturing process) in transferring the design onto the silicon wafer. A family of empirical VT-5 mathematical models involving a variable threshold is analyzed. The models are used in the CAD Calibre, Mentor Graphics Ltd. The results of calibration and verification of the process model for a polysilicon layer produced by the technology of Department of Microtechnology (DMT), Scientific Research Institute of System Analysis, Russian Academy of Sciences, in compliance with the 0.25 μm design standards are reported. The results of verification of the developed model over the contours of complex topological structures are reported. The verification was conducted with the use of the SEMCal module of the CAD Calibre.     

System-level microwave design projects

The teaching laboratory can be an invaluable component of an undergraduate electromagnetics curriculum. This goal of this article is to illustrate several simple but effective microwave-design laboratory projects, involving both system- and component-level design experiences, based upon radar and wireless communications applications. The projects highlighted include a Doppler radar, a simple synthetic aperture radar (SAR), and wireless links using amplitude and frequency-modulation schemes. Students use modern computer-aided design (CAD) tools, coupled with planar technology     

模拟乘法器的建模及其应用

采用CAD技术和典型双极工艺完成模拟乘法器集成电路研制后建立了器件子电路模型,并添加到Pspice模型库中.在设计电路时,用户可以很方便地从模型库中调用子电路模型,提高了设计效率.以立方电路设计为例,介绍了模拟乘法器子电路的建模过程和调用方法.     

Computer-aided design: a case of strategy in implementing a newtechnology

In this case study the introduction of computer-aided design (CAD) in an engineering company was analyzed. The process of change as well as repercussions of the new technology on work organization and communication patterns within the company were studied. The designers has received the new technology favorably and were even impatient about the pace of change. As the development of the system was limited to a small group close to the design management, the introduction had less than desirable effects on the work situation of the designers and on the cooperation with other functions that was envisaged in the planned CAD/CAM step. The study confirms that CAD, as such, will have little effect on a bureaucratic organization unless such a change is included as an explicit objective. For a full utilization of any new technology a joint forum for outlining a strategy is needed     

IC设计数据的语义数据模型

IC设计数据管理是研制一体化IC-CAD系统的重要内容。本文提出了一个适于CAD设计数据管理的语义数据模型及在此模型下IC设计数据的具体表示及管理。语义数据模型提供了表达设计实体及其相互依赖关系的一体化方法。基于此模型的设计数据管理软件已在Unix Sun3工作站上构成,并成功地应用于组合电路逻辑综合系统中。语义数据模型能提高CAD系统的可扩充性,并可很好地支持系统的模块化结构。     

Efficient computer-aided design of ceramic block duplexers

An efficient CAD technique for the design of ceramic block duplexers is presented in this work. The technique makes use of an accurate equivalent circuit extracted from first electromagnetic principles. This circuit is used as the basic tuning tool, which speeds up the design process by avoiding the time consuming electromagnetic simulator. It also indicates the necessary structural changes to achieve the desired response.     

The applicability of computer-aided design as a system engineering tool

The morphology of design and the process of design are examined in an effort to establish a commonality between component and system design which would permit the expansion of design automation. The characteristics of a design problem that make it amenable to computer-aided design (CAD) are defined. The capabilities of CAD for the solution of these problems are analyzed and the difficulties facing the implementer outlined. It is concluded that a methodology for CAD development is essential to its use as a system engineering tool and that among the other needs are: commonality of programs, transferability of programs, better efficiency, and standardization of tools and techniques.     

An Integrated CAD Methodology for Evaluating MOSFET and Parasitic Extraction Models and Variability

An integrated computer-aided design (CAD) framework for evaluating MOSFET and layout parasitic extraction (LPE) models and circuit simulators used in the timing and power analysis of CMOS products is presented. This unified CAD methodology builds a step-wise understanding of the underlying parameter values in the models and their impact on circuit performance. A number of circuit experiments are included to extract the contributions of key MOSFET parameters and physical layout sensitive parasitic elements from circuit simulation results. This CAD setup thus allows easy and detailed comparison of different technologies, device models, and LPE tools to prevent possible bugs in the software as well as inaccuracies in device and parasitic models and timing tools. The software code to carry out the circuit simulations, analysis, and display of the results in an automated fashion has been specifically developed to support this framework. Some of the experiments designed for this work are also placed on the product chip for model-to-hardware correlation. The comparison of the hardware data to the model predictions points to the sources of any discrepancies and aids in tuning the product design to reflect changes in the technology as part of an overall design for manufacturing (DFM) platform