A tale of two designs: the cheapest and the most economic

Engineering economics is the study of how engineers choose to optimize their designs and construction methods to produce objects and systems that will optimize their efficiency and hence the satisfaction of their clients. We discuss some relevant concepts in engineering economics. We begin with the analysis of production and operational costs, and benefit-cost analysis and end with the economic arguments that justify design for testability....Economics is the study of how men choose to use scarce or limited productive resources (land, labor, capital goods such as machinery, and technical knowledge) to produce various commodities (such as wheat, overcoats, roads, concerts, and yachts) and to distribute them to various members of society for their consumption...     

The internationalization of engineering education: a tale of two countries

Two international exchange programs in engineering between universities in Japan and Canada, are described in order to explain the significant benefits gained by the undergraduate and graduate students, as well as the academic staff who participate, and to highlight key principles generally followed in the design and execution of exchange programs. One notable and successful engineering exchange program is between the University of Waterloo, located in Southern Ontario, Canada, and Tottori University in Japan, while the other is between the University of Waterloo and Kyoto University in Japan. Both of these programs include foreign students taking courses for credit or audit at the host university, and, for the case of graduate students, also receiving guidance in their research. Moreover, upon completion of one academic semester in Japan, all of the undergraduate Waterloo students studying at Tottori University are employed in Japanese industry for three to four months before returning to Canada. Of paramount importance to the education of the participating undergraduate and graduate students is the opportunity to learn, by first-hand experience, the language and culture of a foreign country. In fact, one of the key findings of a survey completed by Canadian and Japanese students who took part in the exchange programs, is that living in a different culture greatly enhanced their own personal development. The addition of this international perspective to a solid education in engineering opens many doors of opportunity for exchange program alumni, who are well prepared to fully participate in the global marketplace of the 21st century, and to assist society in responsibly reaching an equitable and sustainable future.     

A cautionary tale about Weibull analysis [reliability estimation]

This paper makes three points about possible perils of unguarded fitting of Weibull distributions to data: (1) bias is introduced by incomplete data, which may have counter-intuitive effects; (2) bias is introduced into percentile estimates by using regression on log-transformed variables to fit the Weibull parameters, particularly if the percentile to be predicted lies outside the range of the data; and (3) the amount of variation associated with such estimates can be very substantial. A partial solution to the incomplete data problem using simulation is presented, and the maximum likelihood approach to parameter estimation and its advantages relative to regression estimation are explained. The problem arose in predicting life expectancy of long-lived components subject to natural aging which cannot be investigated using accelerated testing and for which the collection of data provides an incomplete life record     

逆合成孔径雷达(ISAR)成像

逆合成孔径雷达（ISAR）重点论述用固定雷达对活动目标成像,例如对飞机成像或对船成像等。由于飞机比船只小得多,因此成像也较难,为此,着重综述对飞机的成像。选取了各有代表性模型飞机、真实飞机中的直升机和民航机、还对两架圆周飞行的飞机进行了瞬时双机成像。     

A comparison of two transistor models

The equivalence of Gummel's [1] charge control model and Schilling's [2] regional model for a one-dimensional bipolar transistor is demonstrated.     

Enron: The tale less trumpeted [management]

There are at least two stories of Enron Corp. First is the business story: Houston-based energy giant takes a big (and mysterious) charge, raising questions about its accounting. Its lenders yank their lines of credit, the company collapses, and the massive problem of reorganizing its tangled and far-flung affairs begins. Then there's the scandal. This is a complex and still unfolding story, replete with document shredding, political donations, phone calls to administration officials, unloading of shares by senior executives, an apparent suicide, and charges of accounting fraud stemming from a bewildering array of off-balance sheet entities with curious names. In this paper, the author details hoe the blame falls not just on faulty bookkeeping and inflated expectations, but also on a fashionable but questionable model of stewardship.     

A comparison of two parameter estimation schemes

This letter compares two parameter estimation schemes using the variance of the estimate as the criterion for comparison.     

一种新的关于两电子纠缠的判据

在海森堡绘景下研究外磁场作用下自旋为1/2的耦合二粒子系统纠缠态问题.用数字方法求解该系统极化矢量随时间变化的微分方程组,得到极化矢量随时间的变化规律.计算结果表明,在合适的外磁场条件下,耦合二粒子可以由自旋平行、总的极化矢量z分量为-2的非纠缠态变为纠缠态;得到由非纠缠态变为纠缠态的最佳外磁场条件;提出根据电子的极化矢量随时间的变化来判断耦合二粒子系统是否达到纠缠态的新方法.本方法不需要采用绝热近似,也适用于更复杂的情况,如存在弛豫的体系.     

Dialogic negotiations: a reflective tale of collaboration across the academic-practitioner divide

This article explores the dialogic negotiation processes that can enable professional communication academics and practitioners to collaborate in designing, implementing, and writing up research. Drawing on our experiences conducting a collaborative academic-practitioner case study of technical sales presentations in an executive briefing center, we outline the ways in which we dialogically negotiated research questions, data collection and analysis, theoretical frameworks, organizational contexts, identifications, and interpersonal connections. We then discuss potential limitations of academic-practitioner collaborations and conclude by offering a tentative, contextual list of "best practices" for facilitating successful collaboration across the academic-practitioner divide.     

A study of two adaptive filters in tandem

The tandem of adaptive filters is common in practice. An example is the tandem of echo cancellers in telecommunication networks. This paper analyzes the convergence characteristics and tracking behavior of two adaptive filters in tandem, together with a comparison of its performance with a single adaptive filter. The adaptive algorithm considered is the LMS and the analysis is on mean-square. The coefficient errors correspond to noise, lag bias and lag variance are examined separately The theoretical results are corroborated with simulations. The study shows that the tandem of two adaptive filters decreases the convergence speed compared to a single adaptive filter. In addition, in steady state and when the step-size is small tandeming increases the coefficient variance due to noise by a factor of 2.5, the coefficient variance due to tracking lag by a factor of 1.5, but decreases the mean-square coefficient bias due to lag by a factor of 2     

A Planar transversal junction of two planar waveguides

A rigorous analytic method is used to solve the wave-propagation problem for a planar transversal junction of two planar waveguides. The problem is reduced to an iteratively solved system of integral equations of the second kind. Dependences of the transmission and reflection coefficients of guided waves, radiation patterns, and the power of the radiation field on the ratios of the waveguide thicknesses and the waveguide permittivities are obtained.     

一种拉近两幅图像相似度的算法

在图像处理领域中任意两幅图像都有一定的相似度,它往往是用图像的信噪比来衡量的,但是实验结果表明存在代表同一内容的两幅图像的信噪比却低于代表不同内容的两幅图像的信噪比的情况,这是不合理的,文中通过统计分析待求信噪比的两幅图像的有关特性,自动生成一个系数,对结果图像的每一个像素都乘以该系数,可以提高两幅图像的相似度,且绝对不会降低任意两幅的相似度,实验结果和理论分析说明了文中方法的有效性。     

A full-duplex DLC protocol on two links

The authors consider a special case of multilink protocol, namely, a system consisting of two half-duplex parallel links that carry data in opposite directions between two nodes. They construct a protocol that simulates a full-duplex reliable link between the two nodes. Synchronization is achieved without resorting to the use of serial numbers. A validation proof of the protocol is provided. The design of the protocol exhibits an instance of the value of correctness proofs in the design process, as several successive protocols, discussed in the paper, were only found to be incorrect through the effort to prove them otherwise     

A quartz multivibrator using two regenerative switches

A new quartz multivibrator having a 10-ns transition time is described. The frequency dependence on the supply voltage is less than 10^-6per volt. The output voltage is nearly equal to the supply voltage. The circuit can be heavily loaded.     

A multistate system with two repair distributions

This paper investigates the mathematical model of a reparable system with three possible states—normal, degraded and failed. We consider two types of repair facilities—overhaul and minor repair—having arbitrary pdf. Other transitions have constant rates.     

A comparison of two van-der-Pauw measurement configurations of resistivity

Based on the solution of an electrostatics boundary-value problem, this paper compares two van-der-Pauw-type measurement configurations of resistivity, with respect to the movement of the point-like voltage and current contacts away from the periphery of a thin, square sample. The movement involves both a reduction in the size of the contact array, without any change in its shape or orientation, and a displacement of its center. The formulas derived are applicable to any rigid displacement such that all contacts remain within the boundary of the sample, but only displacements parallel to the edges of the sample or along its diagonal are examined. Both arrays are square, with the first initially coinciding with the corners of the sample and the second initially having its corners centered on the edges of the sample. The solution indicates that the deviation from the ideal van der Pauw resistivity measurement is less sensitive to a reduction in the size of the undisplaced contact array when the first configuration is used. However, under displacements, the situation is complicated markedly by boundary effects, with the results depending on the direction of displacement and the size of the array.     

Understanding China''s telecommunications policymaking and reforms: a tale of transition toward liberalization

By drawing on institutional theory and bargaining theory, this paper analyzes China's telecommunications policymaking mechanism, an important but less-explored issue. Key factors of shaping China's telecommunications policy are examined and the implementation of China's telecommunications policy in network development, competition, foreign direct investment, and regulatory restructuring is investigated. Finally, the impacts of China's entry into the World Trade Organization (WTO) on its telecommunications reform and transition are discussed.     

A novel design of a two operand normalization circuit

This paper presents a new design for two operand normalization. The two operand normalization operation involves the normalization of at least one of two operands by left shifting both by the same amount. Our design performs the computation of the shift by making an OR of the bits of both operands in a tree network, encoding the position of the first nonzero bit. The encoded position is obtained most significant bit first, and then there is an overlapping with the shifting operation. The design we propose replaces two leading zero detector circuits and a comparator, that are present in the conventional approach. Our scheme demonstrates to be more area efficient than the conventional one. The circuit we propose is useful in floating point complex multiplication and COordinate Rotation DIgital Computer (CORDIC) processors     

A comparison of two design methods for MRI magnets

Designs of magnetic resonance imaging (MRI) main magnets obtained from both a functional method and a genetic algorithm method have been compared. While most features in the two approaches are similar, there are several important differences. The functional method leads to fewer coil bundles and a reduced total current, i.e., total ampere turns, (e.g., 6-8 MA) that can be as much as 70% of the total current found with the genetic analysis. While the conclusion about stress is that it is a sensitive function of the choice of wire current density, the designs found with the functional method have a larger hoop stress than that of the genetic design, which may require new or refined manufacturing techniques. Furthermore, the functional approach requires much less computing power (i.e., a personal computer is quite sufficient) while the genetic algorithm method in general demands massively parallel computing techniques. However, in order to search for the optimal magnetic resonance design at a given field strength, it is likely that a combination of these two methods will lead to the best results.     

A review of two dimensional long channel mosfet modeling

To obtain the necessary basic insight into the behaviour of MOSFET needed for device design and optimization, the basic equations must describe the two dimensional characteristics of the device. The increased power and availability of modern digital computers makes such an approach to derive most general and exact solutions feasible. A comprehensive review is made of the attempts at 2d MOSFET modeling.