Fully automated network design by digital computer: Preliminary considerations

Fixed-structure lumped, linear, time-invariant RLC network design problems may be solved by means of the digital computer in terms of gradient techniques in parameter space. Formulation of the network constraint equations in such a way that the variable parameters enter linearly allows the extension of this computer-aided scheme to the design of networks of originally unknown structure. The feasibility of this approach to fully automated network design is illustrated by means of computational examples. The extension to more general network design problems, involving controlled source models and time-variable and nonlinear elements, is discussed in the concluding section.     

Architectural considerations involved in the design of an optical digital computer

Communication problems such as interconnection bandwidth, clock skew, and connectivity restrict computational throughput. Bandwidth and clock skew problems limit the speed and add to the design complexity. Constrained connectivity forces a significant portion of the speed of a processor to be used to compensate for the limited number of interconnections. Philosophically, the large bandwidth, innate parallelism, and noninterfering propagation of optics offer mechanisms for overcoming these communication problems. The difficulty in exploiting these capabilities has been the absence of suitable optical logic and memory devices. Technologically, optical bistability and other advances in electrooptics now offer the possibility of cascadable optical logic elements with speed and power dissipation comparable with electronics. Architecturally, a parallel pipelined structure can be used to simplify the optical memory requirements as well as exploit the communication capabilities of optics.     

Imminent policy considerations in the design and management ofnational and international computer networks

Policy questions in network operation that must be addressed, including privacy, export policy, and access policy, are discussed. Concerns about the adequacy of the existing policy-setting mechanisms and a number of legal issues that are cropping up as networks expand are considered. Existing systems, such as the telephone system, the highway network, and the Internet computer network, are briefly investigated to assess how these systems handle policy issues in order to obtain insight into resolving policy questions related to future networks     

The design document: key to managing documentation development

It is pointed out that the design document is an effective way of managing documentation development, particularly in large-scale projects. It provides a rough picture or sketch of the information before the writing begins, thereby permitting changes in design before the course of the documentation is set. Once finished, it becomes a road map for writers, managers, and developers. It can later be used to verify that the design was implemented in the final text for publication. It is concluded that, although on first appearance it might seem that a design document simply adds one more thing to do on a project, the added effort is more than compensated for by the amount of time and money saved in not having to modify information at a much later point     

Transfluxor design considerations

The transfluxor is a new magnetic device for use in information handling and nondestructive storage systems. The location and sizes of each of the several apertures determine many of the operating characteristics of the device. This paper discusses the various geometric and magnetic factors that should be considered before deciding upon a core configuration. Two methods, one based on a graphical approach, the other on mathematics, are outlined to determine the optimum shape for a particular application. A procedure may be reversed to predict the performance of existing cores. The flux storage principles are described and the equationPhi_{s} = kI_{c} - k'is derived. This equation shows the relationship between the input current Icand the stored fluxPhi_{s}. kandk'are design constants depending on the magnetic and physical properties of a core. Comparisons are made between a 346-mil (OD) core and one of 83 mils. Estimates are given as to the practical limits to which core miniaturization may be carried using existing fabrication methods.     

Microwave phototube design considerations

The general behavior of the traveling-wave microwave phototube (TWP) as a broadband light demodulator has been described in previous publications. This paper presents specific theoretical and experimental analyses. It is shown that at low average currents the microwave power output of a TWP is given byP = frac{1}{2}i^{2} R_{eq}whereiis the peak value of the microwave current modulation at the cathode (i.e., the ac current) and Reqis an "equivalent interaction resistance" given byR_{eq} = pi^{2}N^{2}Z_{c}whereNis the helix length in electronic wavelengths and Zcis the longitudinal beam-circuit interaction impedance. Typical values of Reqare from 10⁵to 10⁷ohms. The bandwidth is determined by the productf^{2}Z_{c}, which can vary less than 3 db over an octave. The major noise contributions are found to be shot noise and thermal noise. The power output and signal-to-noise calculations are verified by experiments on an S-band TWP at low average current levels. Preliminary analysis of the TWP at high average currents shows that even higher values of Reqshould be obtainable. However, in that case the frequency-dependent microwave interactions in the gun region may provide a serious bandwidth limitation.     

A conceptual framework for ASIC design

An attempt is made to gain a better understanding of the nature of ASIC (application-specific integrated circuit) design. This is done from a decision-making perspective, in terms of three knowledge frames: the design process, the design hyperspace, and the design repertoire. The design process frame emphasizes the hierarchical design approach and presents the methodology as a formalization of the design process. The design hyperspace concept relates to the recognition of design alternatives. Analysis techniques for evaluating algorithmic and architectural alternatives are collected and classified to form the design repertoire. This conceptual framework is an effective instrument for bridging the widening gap between system designers and VLSI technology. It also provides a conceptual platform for the development of tools for high-level architectural designs     

Model relations between conceptual and detail design

Conceptual design, as an essential step towards successful mechatronic product development, should be supported by good models for the design map, which in turn expresses the relationship between the design parameters and the functional requirements. If feasible, these models should be mathematical. In this paper the close correlation between a good concept and its models is postulated. A theory is presented how these models are related to models employed for detail design and how good concept models can be characterised. The practical realisation of this characterisation relies on the decomposability of the whole design map in several low dimensional decoupled parts. This corresponds to Suh’s independence axiom. Modelling aspects of the development of an energy saving hydraulic variable valve train for combustion engines are used as a demonstrative example.     

On conceptual design of intelligent mechatronic systems

We have technology now to design networks of small intelligent units capable of competing and/or co-operating with each other on specified tasks and making decisions under conditions of uncertainty through a process of negotiation. In highly dynamic environments, such distributed systems are capable of achieving considerably better results in terms of performance/cost ratio and reliability than conventional centralised large systems and structures. The major elements of these systems are intelligent agents, which are software objects capable of communicating with each other, as well as reasoning about received messages. The paper discusses conceptual design of mechatronic systems based on multi-agent technology.     

Usability engineering as a part of the software design process

To ensure software quality, European and American institutions have followed different approaches: while the European-based ISO standard prescribes a software development process, the American maturity model rates the currently used development process. In central Europe, the V-model has achieved some popularity. However, it is not compatible with the maturity model approach — it covers only two thirds of the lowest maturity level. Both approaches can be enhanced with usability engineering methods. There is a wide range of tools for different purposes which can be fit in various stages of the process.     

Lighting the way in computer design

The development of optical interconnect technology using fiber optics in the 1970s was a cornerstone of the modern telecommunication industry. Replacing copper cables with optical fibers provides superior performance in terms of wide data bandwidths, reduced noise, and low loss. It also significantly reduces the cost of communication in terms of dollars/bit/km. Optical interconnects not only provided the infrastructure critical to the explosive, growth of telecommunication that followed, but also paved the way for the information industry to flourish today     

基于ANN交互式遗传算法的智能手机外观概念设计研究

针对智能手机外观的概念设计过程不能很好的满足客户的个性化需求,本文引入交互式遗传算法（Interactive Genetic Algorithms,IGA）,建立了智能手机外观的概念设计系统框架,使得客户能够直接参与到设计中,并使用人工神经网络（Artificial Neural Networks,ANN）来解决交互式遗传算法的用户疲劳度问题.通过建立智能手机外观概念设计系统,进行实证分析,实验表明,本方法能够有效的满足客户的个性化需求,具有很好的应用前景.     

A conceptual framework for international Web design

We develop a conceptual framework for exploring significant differences in how people from diverse cultural backgrounds and with diverse individual characteristics might perceive and use Web documents. This is the first stage of a large multistage empirical study of user satisfaction and effectiveness of various Web designs based on cultural and individual factors. We identify six cultural factors and six individual factors that could impact the effectiveness of Web documents. The six cultural factors include: power distance, individualism versus collectivism, masculinity versus femininity, anxiety avoidance, long-term versus short-term orientation, and polychronic versus monochronic time orientation. The six individual factors include: demographics (age and gender), professional knowledge, information technology knowledge, flexibility, information processing abilities, and cultural knowledge. Based on the conceptual model proposed, we develop a number of testable, specific propositions on how Web document effectiveness could be impacted by the cultural and individual factors in various Web designs. In order to measure document effectiveness of each design, we identify components of Web document effectiveness as perceived usability, reliability, clarity, and comprehension that, in turn, influence readers' overall satisfaction with Web documents. Using the propositions presented, one can measure and analyze how cultural and individual factors influence users' satisfaction, which will assist researchers, educators, and communicators working with various Web designs     

Reliability prediction models to support conceptual design

During the early stages of conceptual design, the ability to predict reliability is very limited. Without a prototype to test in a lab environment or without field data, component failure rates and system reliability performance are usually unknown. A popular method for early reliability prediction is to develop a computer model for the system. However, most of these models are extremely specific to an individual system or industry. This paper presents three general procedures (using both simulation and analytic solution techniques) for predicting system reliability and average mission cost. The procedures consider both known and unknown failure rates and component-level and subsystem-level analyzes. The estimates are based on the number of series subsystems and redundant (active or stand-by) components for each subsystem. The result is a set of approaches that engineers can use to predict system reliability early in the system-design process. Software was developed (and is discussed in this paper) that facilitates the application of the simulation-based techniques. For the specific type of system and mission addressed in this paper, the analytic approach is superior to the simulation-based prediction models. However, all three approaches are presented for two reasons: (1) to convey the development process involved with building these prediction tools; and (2) the simulation-based approaches are of greater value as the research is extended to consider more complex systems and scenarios     

Breakdown voltage design considerations in VDMOS structures

Analytical closed-form expressions for the breakdown voltage in punched-through VDMOS structures, including the effect of floating guardrings and field plates, are derived in this paper. The theoretical results are confirmed by measured data on VDMOS devices, as well as on floating-guardring diode test structures, fabricated on n/n⁺epitaxial substrates.     

Polyimide-related design considerations in a bipolar technology

It is found that a spurious leakage path from the emitter to the collector of a lateral p-n-p or a trench-defined n-p-n device may be induced by the applied collector voltage. This voltage influences the surface potential at the emitter-base junction through the charging of the polyimide used as interlevel dielectric or as trench fill, respectively. A simple model of the effect is developed, and several successful process features are discussed     

计算机辅助试验设计

计算机辅助试验研究(Computer Aided Research,简称CAR系统是大型试验设计和分析应用软件包.由实验设计,建模分析,试验优化三大模块组成,具有功能比较完善,数据处理灵活和使用方便等特点.实验设计模块可辅助人工设计试验,建模分析模块可作回归分析和方差分析,试验优化找出最好的试验条件.     

TMT三镜被动支撑系统的概念设计

TMT（Thirty Meter Telescope）望远镜是一台R-C式的30 m口径光学红外望远镜,其三镜为椭圆形平面镜,口径为3.594 m2.568 m,质量达到1.8 t,三镜系统需要把来自次镜的光折转到望远镜两侧耐氏平台上的一系列科学仪器上,具有跟踪和快速定向功能。支撑系统包括底支撑系统和侧支撑系统,根据TMT对三镜的面形要求,提出了底支撑系统采用18点Whiffletree结构,通过优化分析,面形RMS值达到118.5 nm。针对侧支撑系统,提出了基于kinematics原理的12点支撑方式,侧支撑作用下的面形RMS值为4.7 nm,两者综合作用下的面形RMS值优于77 nm。按照支撑系统方案,设计了一种满足一定质量和体积要求的支撑系统结构。     

基于"功能-原理-结构"的计算机辅助概念设计模型

计算机辅助概念设计是产品设计早期阶段中的关键阶段.然而,传统的计算机辅助概念设计主要集中于产品几何设计阶段.因此,在产品设计初期,许多产品设计信息被忽略.建立了"功能-原理-结构"概念设计模型.初始产品设计信息存储于不同的模型层中.建立了功能、原理、结构数据库.在"功能-原理-结构"模型的帮助下,实现了由功能到原理再到结构的映射.建立了概念设计应用系统来验证"功能-原理-结构"求解模型.