811 research outputs found

    Object oriented fault diagnosis system for space shuttle main engine redlines

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    A great deal of attention has recently been given to Artificial Intelligence research in the area of computer aided diagnostics. Due to the dynamic and complex nature of space shuttle red-line parameters, a research effort is under way to develop a real time diagnostic tool that will employ historical and engineering rulebases as well as a sensor validity checking. The capability of AI software development tools (KEE and G2) will be explored by applying object oriented programming techniques in accomplishing the diagnostic evaluation

    Efficient Spin Injection into Silicon and the Role of the Schottky Barrier

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    Implementing spin functionalities in Si, and understanding the fundamental processes of spin injection and detection, are the main challenges in spintronics. Here we demonstrate large spin polarizations at room temperature, 34% in n-type and 10% in p-type degenerate Si bands, using a narrow Schottky and a SiO2 tunnel barrier in a direct tunneling regime. Furthermore, by increasing the width of the Schottky barrier in non-degenerate p-type Si, we observed a systematic sign reversal of the Hanle signal in the low bias regime. This dramatic change in the spin injection and detection processes with increased Schottky barrier resistance may be due to a decoupling of the spins in the interface states from the bulk band of Si, yielding a transition from a direct to a localized state assisted tunneling. Our study provides a deeper insight into the spin transport phenomenon, which should be considered for electrical spin injection into any semiconductor

    IP Security

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    IP is stands for Internet Protocol. IP security is a set service which secures the documents by the unauthorized entity. IP Sec covers the three areas of functionality that is authentication, confidentiality, and key management. IP Sec encrypts and authenticates all the data traffic at the IP level security. The IP level security or firewall administrator, we got basically the same concerns (as plumber) the size of the pipe the contents of the pipe, making sure the correct traffic is in the correct pipes and keeping the pipes from splitting and leaking all over the places of course like plumbers. When the pipes do leak: we are the ones responsible for cleaning up the mess and we are the ones who come up smelling awful. Firewall is a device that is used to provide protection to a system from network-based security threats. Firewall uses service, behavior, user and direction control techniques

    Security: Hash Function-authentications

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    As security or firewall administrator, we got basically the same concerns (as a plumber) the size of the pipe the contents of the pipe, making sure the correct traffic is in the correct pipes and keeping the pipes from splitting and leaking all over the places of course like plumbers. When the pipes do leak: we are the ones responsible for cleaning up the mess and we are the ones who come up smelling awful. Firewall is a device that is used to provide protection to a system from network-based security threats. The firewall uses service, behavior, user and direction control techniques

    Effect of microencapsulated plant extracts on mosquito repellency

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    Mosquitoes are the most important single group of insects in terms of public health importance. Mosqui-toes not only cause nuisance by their bites but also transmit deadly diseases. The activity of mosquitoes is affected by climate, light and temperature. In tropical areas like India, the population of mosquitoes is found huge day by day. Repeated use of synthetic insecticides for mosquito control has disrupted environment as well as human health. To overcome this problem, plant derived compounds may be the better alternate over synthetic insecticides. To enhance the health and hygiene qualities by means of use of medicinal plants through effective application technique on textiles, marigold (petals) and nirgundi (leaves) methanol extract was used as mosquito repellent finish on 100 % woven cotton. For applying mosquito repellent finish on fabric, complex coacervation technique of microencapsulation was used through pad-dry-cure method. Finished cotton samples were tested against Anopheles stephensi by using laboratory cage method for their efficacy and durability to washing and sun-drying as per standard test methods. Marigold (petals)and nirgundi (leaves) extract finished fabric samples showed 96 and 94 % repellency respectively after 60 minutes of observation. It remained 56 % and 54 % (after 15 washes) and 54 and 52 % (after expo-sure in sun for 3 hours) by the application of marigold and nirgundi extracts respectively. Hence, microencapsulation technique on selected cotton textile proved effective to repel mosquitoes up to acceptable level according to WHO (1996)

    Multi-factor Authentication and Their Approaches

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    A multi-factor authentication is an approach to authentication which requires the presentation of two or more of the three authentication factors: a knowledge factor ("something the user knows"), a possession factor ("something the user has"), and an inherence factor ("something the user is"). Two-factor authentication seeks to decrease the probability that the requestor is presenting false evidence of its identity. In reality, there are more variables to consider when establishing the relative assurance of truthfulness in an identity assertion than simply how many "factors" are used. The U.S. Federal Financial Institutions Examination Council issued supplemental guidance on this subject in August 2006, in which they clarified, "By definition true multifactor authentication requires the use of solutions from two or more of the three categories of factors

    How Do Glassy Domains Grow?

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    We construct the equations for the growth kinetics of a structural glass within mode-coupling theory, through a non-stationary variant of the 3-density correlator defined in Phys. Rev. Lett. 97}, 195701 (2006). We solve a schematic form of the resulting equations to obtain the coarsening of the 3-point correlator χ3(t,tw)\chi_3(t,t_w) as a function of waiting time twt_w. For a quench into the glass, we find that χ3\chi_3 attains a peak value tw0.5\sim t_w^{0.5} at ttwtw0.8t -t_w \sim t_w^{0.8}, providing a theoretical basis for the numerical observations of Parisi [J. Phys. Chem. B 103, 4128 (1999)] and Kob and Barrat [Phys. Rev. Lett. 78, 4581 (1997)]. The aging is not "simple": the twt_w dependence cannot be attributed to an evolving effective temperature.Comment: 6 pages, 5 figure
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