14,108 research outputs found

    An overview of NASA's digital fly-by-wire technology development program

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    The feasibility of using digital fly-by-wire systems to control aircraft was demonstrated by developing and flight testing a single channel system, which used Apollo hardware, in an F-8C test airplane. This is the first airplane to fly with a digital fly-by-wire system as its primary means of control and with no mechanical reversion capability. The development and flight test of a triplex digital fly-by-wire system, which will serve as an experimental prototype for future operational digital fly-by-wire systems, is underway

    A Cloud-based RFID Authentication Protocol with Insecure Communication Channels

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    © 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Radio Frequency Identification (RFID) has becomea widespread technology to automatically identify objects and withthe development of cloud computing, cloud-based RFID systemsattract more research these days. Several cloud-based RFIDauthentication protocols have been proposed to address privacyand security properties in the environment where the cloudprovider is untrusted therefore the tag’s data are encrypted andanonymously stored in the cloud database. However, most of thecloud-based RFID authentication protocols assume securecommunication channels between the reader and the cloud server.To protect data transmission between the reader and the cloudserver without any help from a third party, this paper proposes acloud-based RFID authentication protocol with insecurecommunication channels (cloud-RAPIC) between the reader and the cloud server. The cloud-RAPIC protocol preserves tag privacyeven when the tag does not update its identification. The cloudRAPIC protocol has been analyzed using the UPriv model andAVISPA verification tool which have proved that the protocolpreserves tag privacy and protects data secrecy

    Preliminary design of a 100 kW turbine generator

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    The National Science Foundation and the Lewis Research Center have engaged jointly in a Wind Energy Program which includes the design and erection of a 100 kW wind turbine generator. The machine consists primarily of a rotor turbine, transmission, shaft, alternator, and tower. The rotor, measuring 125 feet in diameter and consisting of two variable pitch blades operates at 40 rpm and generates 100 kW of electrical power at 18 mph wind velocity. The entire assembly is placed on top of a tower 100 feet above ground level

    Scalable Exact Parent Sets Identification in Bayesian Networks Learning with Apache Spark

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    In Machine Learning, the parent set identification problem is to find a set of random variables that best explain selected variable given the data and some predefined scoring function. This problem is a critical component to structure learning of Bayesian networks and Markov blankets discovery, and thus has many practical applications, ranging from fraud detection to clinical decision support. In this paper, we introduce a new distributed memory approach to the exact parent sets assignment problem. To achieve scalability, we derive theoretical bounds to constraint the search space when MDL scoring function is used, and we reorganize the underlying dynamic programming such that the computational density is increased and fine-grain synchronization is eliminated. We then design efficient realization of our approach in the Apache Spark platform. Through experimental results, we demonstrate that the method maintains strong scalability on a 500-core standalone Spark cluster, and it can be used to efficiently process data sets with 70 variables, far beyond the reach of the currently available solutions

    Airborne Advanced Reconfigurable Computer System (ARCS)

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    A digital computer subsystem fault-tolerant concept was defined, and the potential benefits and costs of such a subsystem were assessed when used as the central element of a new transport's flight control system. The derived advanced reconfigurable computer system (ARCS) is a triple-redundant computer subsystem that automatically reconfigures, under multiple fault conditions, from triplex to duplex to simplex operation, with redundancy recovery if the fault condition is transient. The study included criteria development covering factors at the aircraft's operation level that would influence the design of a fault-tolerant system for commercial airline use. A new reliability analysis tool was developed for evaluating redundant, fault-tolerant system availability and survivability; and a stringent digital system software design methodology was used to achieve design/implementation visibility
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