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Aerospace and Electronic Systems Magazine, IEEE

Issue 4 • Date April 1997

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Displaying Results 1 - 8 of 8
  • Reflector antenna analysis by simple photography

    Publication Year: 1997 , Page(s): 3 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1510 KB)  

    The performance of a conventional microwave parabolic dish reflector can be estimated from a 35 mm photo, which is taken when the dish is illuminated by a small light bulb mounted at its feed point. Both random surface errors, structural deformations and feed positioning problems can be analyzed. If only go/no go-information is needed, no optical interferometry is necessary. View full abstract»

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  • "New Developments Reported at the 12th Annual Battery Conference"

    Publication Year: 1997 , Page(s): 30 - 37
    Save to Project icon | Request Permissions | PDF file iconPDF (780 KB)  
    Freely Available from IEEE
  • New Math Lessons Learned

    Publication Year: 1997 , Page(s): 41
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (124 KB)  

    First Page of the Article
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  • Changing the World - Inventors Do It! the Invention that Changed the World [Book Review]

    Publication Year: 1997 , Page(s): 42 - 44
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    Freely Available from IEEE
  • Iris recognition technology

    Publication Year: 1997 , Page(s): 23 - 29
    Cited by:  Papers (11)  |  Patents (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (768 KB)  

    IriScan Inc. has been developing an identification/verification system capable of positively identifying and verifying the identity of individuals without physical contact or human intervention. A new technology, using the unique patterns of the human iris, shows promise of overcoming previous shortcomings and providing positive identification of an individual without contact or invasion, at extremely high confidence levels. The video-based system locates the eye and iris; evaluates the degree of occlusion by eyelid and spectral reflection; determines the quality of image focus; and determines the center and boundary of the pupil and the limbus (outer edge of the iris) for processing. The iris is zoned, and the features therein measured and encoded into a 256-byte (2048 bit) IrisCode for enrollment or identification. The presented biometric is compared to an extensive database for identification, or to a referenced IrisCode for verification. Computations and decisions are accomplished at extremely high rates of speed, resulting in processing times of less than two seconds. The process is based on the unique nature and extreme richness of the human iris. The multiple features produce a non-duplicable organ with more than 400 degrees of freedom, or measurable variables. The IriScan process typically uses about 200 of these to create a code which can be compared to an entire database in milliseconds, producing a positive identification with “imposter odds” as high as 1 in 1034 View full abstract»

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  • Technical trends in the future

    Publication Year: 1997 , Page(s): 38 - 39
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (168 KB)  

    On the day that Raytheon bought Hughes Electronics, A.N. Chester described how aerospace executives evaluate options for research programs. Their objective is to develop products that have value after the planned work is completed. Big changes are taking place in the environment in which a new commercial product must succeed. By “environment” means the official and unofficial rules created by social pressures, government decisions, industrial activity, and financial activity View full abstract»

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  • Reduced minimum configuration fiber optic gyro for land navigation applications

    Publication Year: 1997 , Page(s): 18 - 21
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (520 KB)  

    Further cost reduction of the fiber optic gyroscope is necessary to meet the economic requirements of land navigation systems. Previous concentration was on the reduction of the number of splices and component improvements in the open-loop minimum configuration. Now non-essential components and splices are eliminated. The source-detector coupler is not part of the Sagnac interferometer, and serves solely to direct light from the interferometer into the output photodetector. Many commercial laser diodes incorporate a back-facet photodetector to monitor laser intensity. The signal returned from the Sagnac traverses the laser, and can be detected at this photodetector. The gyro signal can be distinguished from the laser signal by the bias modulation applied in the interferometer. Configuring a gyro in this manner eliminates a directional coupler and the separate photodetector, as well as up to two fiber splices in an all-fiber gyroscope. A production, open-loop fiber optic gyroscope has been modified to demonstrate this principle. The gyroscope exhibits performance comparable to the conventional minimum configuration View full abstract»

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  • Security intrusion process: an empirical model

    Publication Year: 1997 , Page(s): 7 - 17
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1012 KB)  

    This paper describes a security model developed from empirical data collected from a realistic intrusion experiment in which a number of undergraduate students were invited to attack a distributed computer system. Relevant data, with respect to their intrusion activities, were recorded continuously. We have worked out a hypothesis on typical attacker behavior based on experiences from this and other similar experiments. The hypothesis suggests that the attacking process can be split into three phases: the learning phase, the standard attack phase and the innovative attack phase. The probability for successful attacks during the learning phase is expected to be small and, if a breach occurs, it is rather a result of pure luck than deliberate action. During the standard attack phase, this probability is considerably higher, whereas it decreases again in the innovative attack phase. The collected data indicates that the breaches during the standard attack phase are statistically equivalent. Furthermore, the times between breaches seem to be exponentially distributed, which means that traditional methods for reliability modelling of component failures may be applicable View full abstract»

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The IEEE Aerospace and Electronic Systems Magazine publishes articles and tutorials concerned with the various aspects of systems for space, air, ocean, or ground environments.

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