Fuel cells for “personal electricity”

Cars powered by fuel cells have been built and tested; however, the aerospace fuel cells could not deliver high power quickly when the driver wanted to accelerate his car. Today's hybrid electric cars carry a battery that supplies the acceleration power, and the prime power source, whether an engine or fuel cell, is not stressed with sudden load peaks. Zero air pollution becomes attainable when fuel-cells supply the prime power on a hybrid vehicle     

Training, career development and registration for safety criticalsoftware systems specialists

A career development program for information systems practitioners currently being used widely by employers in the UK and now becoming available in North America is described. The program, called the Professional Development Scheme (PDS), was developed by the British Computer Society to address the lack of structure and quality control generally present in the way computing professionals were being trained. The performance standards underpinning the program (The British Computer Society Industry Structure Model) have been thoroughly updated and now include material specific to the development, maintenance, and management of software for safety-critical applications. The use of the program for this purpose and potential developments in the field of training and registration for safety-critical software specialists are discussed     

The role of the professional society in the career development ofengineers

The role of the professional engineering society in the career development of the engineer as he/she progresses through various stages of growth is examined. Beginning with the definition of an engineer, professional development is categorized in a four-stage model that begins at the apprentice level and ultimately culminates in the sponsor or director level. Civilian engineer career development at the Aeronautical Systems Division at Wright-Patterson Air Force Base is discussed in terms of the four-stage model. Key factors in career progression are enumerated. The role and impact of the professional society on an engineer's development is examined. The activities of the Engineering Management Society of the IEEE at the local level are reviewed. The critical role of government/industry/academic management policy on participation of their engineers in professional-society activities is debated     

“Dakota Sun”-the next generation solar powered racingvehicle

Based on the experience gained from Sunrayce '95, the Solar Motion Team has made many changes to the design of the next generation solar car. These changes have resulted in a vehicle that is very different from the “Solar Rolar”, The Dakota Sun is a three wheeled vehicle with separate cab and solar array. This design allows for improved aerodynamics, decreased weight, lower rolling resistance, and ease of manufacture compared to the four wheeled catamaran used in the last race. However, this design sacrifices total enclosed wheel base area, additional room for components, and added power from side solar panels, The major objectives for the team's redesigned Sunrayce '97 entry are: systems integration; decrease the weight of the car; decrease aerodynamic drag; more efficient use of available energy; and increased driver safety. The team has set a standard to use the latest available technology. Although this increases the complexity of the components, by using a systems engineering approach the “Dakota Sun” has evolved into a more integrated vehicle. This philosophy of integrated design has resulted in great improvements in mechanical design and manufacturing techniques, as well as electrical innovations. The major design changes evident from the original Sunraycen '95 vehicle are the result of an evolutionary design process that has produced the highly competitive Sunraycel '97 design outlined in this article     

管制员职业发展危机期的激励管理探析

每个人的职业生涯总不是一帆风顺,既会经风雨,又会见彩虹。研究管制员职业发展的各个阶段,关注其职业成长历程中的各种问题,特别是该过程中的几个危机阶段可以帮助我们了解管制员在不同阶段的特点及发展需要,为管制单位管理者进行有针对性的队伍建设打下基础,从而有效地促进管制员队伍整体素质的提高和发展。     

Comment on “Inversion of all principal submatrices of amatrix”

The paper by Koc and Chen (1994) includes new formulas for computational complexity, but the method itself is already known and has dubious numerical stability. A poorly conditioned example is shown     

High resolution 3D “snapshot” ISAR imaging and featureextraction

We have developed a new formulation for three dimensional (3D) radar imaging of inverse synthetic aperture radar (ISAR) data based on recent developments in high resolution spectral estimation theory. Typically for non real-time applications, image formation is a two step process consisting of motion determination and image generation. The technique presented focuses on this latter process, and assumes the motion of the target is known. The new technique offers several advantages over conventional techniques which are based on the correlation imaging function. In particular, the technique provides for a direct 3D estimate (versus back projection to a 3D target grid matrix) of the locations of the dominant scattering centers using only a minimum set of independent 2D range-Doppler ISAR “snapshots” of the target. Because of the snapshot nature of the technique, it is particularly applicable to 3D imaging of sectors of sparse-angle data, for which the sidelobes of the correlation imaging integral become high. Furthermore, the technique provides for an estimate of amplitude and phase of each scattering center as a function of aspect angle to the target, for those aspect angles which encompass the set of 2D range-Doppler snapshots. Results illustrating the technique developed are presented for both simulated and static range data     

New approaches to weapon system testing or “back to thefuture”

This paper proposes abandoning the use of multipurpose ATE for “horizontal” support of weapon systems in favor of returning to “vertical” support. An R&D effort is proposed to develop a software “hot mock-up” system for field testing weapon system assemblies     

Comment on “A new approach to robust fault detection andidentification”

In the paper by M. Saif and Y. Guan (see ibid., vol. 3, no 29, p. 685-695), a necessary and sufficient condition is given for the existence of an asymptotically stable observer in the case of p=m. The objective of this note is to point out a critical mistake in the main theorem of the paper     

Comments on “Effect of wet snow an the null-reference ILSsystem”

The subject paper (July 1993) has raised some issues regarding the probability of the Instrument Landing System (ILS) radiating out-of-tolerance vertical guidance signals. An independent study has substantiated the findings of that paper and adds further concern regarding some FAA ILS snow procedures. The principal conclusions of this paper are: 1) an analysis, based on Walton's discovery of rare snow conditions that cause the null-reference ILS antenna image to disappear, indicates that these conditions can cause out-of-tolerance guidance signals, 2) operation without a monitor of the image radiation can result in signal-in-space guidance signal errors that are significantly beyond the intended limit values, and 3) the integrity of image glide path equipment in snow environments does not satisfy the ILS integrity requirements     

Comments on “Discrete-time observability and estimabilityanalysis for bearings-only target motion analysis”

Discusses the extensive mathematical analysis carried out by the authors of the original paper [see ibid., vol. 33, no. 1, p. 178-201, 1997] and submits the following points. The authors used pseudo measurements for recasting the observability problem into a linear framework. They treated the bearings-only passive target tracking system as a deterministic system. It is already established that for deterministic systems, the pseudo measurements are linear functions of the states of the system, though the coefficient matrix is a nonlinear function of the original measurements, By using the pseudo measurements in a linear observer, global stability can be shown. However, if the pseudo measurement observer, for which the analysis is mostly carried out by the authors, is used in a noisy environment as a pseudo measurement filter (PMF), biased estimates are arrived at. Hence, though the approach of authors is quite direct and provides insights about the algebraic structure of the BOT problem, as pseudo measurements are used throughout the analysis is not of much use to the TMA community, as the nonlinear measurement equation along with measurement noise are required to be considered in the BOT problem to obtain unbiased results     

Comments on “A method for improving extended Kalman filterperformance for angle-only passive ranging”

Some history of this bearings-only problem at Sperry dating from 1965 is presented. The erratic estimation problems were soon recognised and labeled the “Collapse of the Covariance Matrix Problem”. A solution was soon found as a relation transformation on the covariance matrix. The angle of rotation was the difference between estimates of bearing before and after a measurement update. Based on a comparison of covariance analyses for simulated problems using the true bearings with Monte Carlo results it was concluded that no further significant improvement could be achieved. This conclusion is yet to be disproved     

Further comments on “Optimal sensor selection strategy fordiscrete-time estimators” [and reply]

The fundamental TPBVP usually underlying true “optimal sensor selection strategy” is revisited to obtain practical real-time mechanizations as a solution to an exclusively initial value problem     

“Test technology and commercialization-past, present andfuture”. Theme of AUTOTESTCON '96

AUTOTESTCON '96, jointly sponsored by AESS and the Instrumentation and Measurement Society (I&MS), was held September 16-19 in Dayton, OH, the birthplace of aviation. As the largest test conference, it provides a valuable forum for the exchange of information relating to automatic test systems (ATS). The conference has continued to grow both in attendance and in exhibition space. This year's conference emphasized improving test system effectiveness in the presence of exploding computer technology and the changing military and commercial environment. The impact of DoD acquisition reform on test was also examined     

A new career world for engineers

“Every Engineer a Leader” was the theme of this year's two-day Careers, sponsored last April in Fort Worth by the IEEE US Activities Board. The General Chairman was Nigel Bristow, and speakers ranged from an engineer who had started a consulting service to engineering-career researchers and corporate executives. The engineers professional world, from the top down, is changing at an exponentially increasing rate. For example, the prime life of a new personal computer is only 60 days, and the next version had better be well on its way to the market by then, explained Jerre L. Stead, CEO of ATT Global Information Solutions, at the IEEE Careers Conference. One result: six out at seven CEOs of the biggest computer companies had been fired in the previous year. During his normal workweek Stead was visiting six cities to talk with customers. During a busy week he had visited six countries!     

基于目标管理的大学生涯规划设计探析

目标管理是20世纪50年代中期,在科学管理和行为管理理论基础上形成的一套管理理论,是现代化管理的一项重要内容.本文将目标管理理论应用于大学生涯规划设计,主要从大学生涯规划设计的内涵、意义、主要内容和有效途径探讨了大学生涯规划设计,以便解决大学新生入学后的目标缺失问题.     

管制员职业韧性的培养与提升

在管制员职业生涯发展过程中,由于空管各级组织的发展、外界环境以及管制员自身发展需求的变化,使管制员在职业发展过程中面临各种挑战,特别是到了管制员职业生涯发展的中后期,管制员极可能面对职业高原和职业倦怠等不利因素的困扰。所以,如何不断培养管制员的职业韧性,积极应对管制员职业高原和职业倦怠已成为管制员职业生涯管理的难     

始终坚持安全发展、和谐发展、科学发展——新中国民航空管60年发展的启示

我国不仅拥有960万平方公里陆地面积,还管辖着1080多万平方公里空域。空中交通管理工作承担着指挥飞行、开发空域等重大职责。伴随着新中国民航60年来的快速发展,民航空管事业也实现了由无到有、由弱到强的飞跃。     

劳动力市场建设刍议

章在分析我国目前劳动力市场现状的基础上，提出劳动力市场建设的近期目标，以及实现这一目标的基本工作和具体措施。