Raytheon

About: Raytheon is a company organization based out in Waltham, Massachusetts, United States. It is known for research contribution in the topics: Signal & Antenna (radio). The organization has 15290 authors who have published 18973 publications receiving 300052 citations.

An integrated maritime surveillance system based on high-frequency surface-wave radars. 2. Operational status and system performance

Abstract: For pt.1 see ibid., vol.43, no.4, p.28-43 (2001). An integrated maritime surveillance (IMS) system, based on high-frequency surface wave radars (HFSWR), for monitoring surface and low-level air activity within the 200 nautical mile (nm) Exclusive Economic Zone (EEZ) is described in this two-part paper. The science behind the long-range performance of HFSWR was presented in Part 1(Sevgi et al. 2001). The system described was installed on Canada's east coast, where it is being used to demonstrate continuous, all-weather surveillance of the EEZ to beyond 200 nm. The system consists of two land-based HFSWRs and an operations control center (OCC). The two unmanned radars provide coverage of the Grand Banks region of Newfoundland, renowned for its offshore resources, particularly fish and oil. The system has been designed to assist authorities to more efficiently monitor such illegal activities as drug trafficking, smuggling, piracy, illicit fishing and illegal immigration. In addition, the system may be used for tracking icebergs, environmental protection, search and rescue, resource protection, sovereignty monitoring, and remote sensing of ocean surface currents and winds. Extensive performance testing of the system has been conducted using the two fully functional radars. It is shown that the HFSWR system complements existing surveillance assets to dramatically increase the effectiveness of air and surface reconnaissance missions by vectoring them directly to targets of interest.

Product Reliability, Maintainability, and Supportability Handbook

Abstract: PRODUCT EFFECTIVENESS AND WORTHProduct AttributesProgrammatic FactorsProduct Effectiveness FactorsOperational AvailabilityDesign, Use, and Logistic EffectivenessDesign Effectiveness.. Use Effectiveness. Logistic EffectivenessReliabilityMission Reliability. Logistic ReliabilityRestorationMaintainabilityTime Elements and Product EffectivenessRelationships among Time IntervalsAssigning ResponsibilityIntegrated Product and Process DevelopmentManaging Product EffectivenessSummaryPROBABILITY CONCEPTSRandom EventsDefinitions of ProbabilityBasic Theorems of ProbabilityConditional Probability and Multiplication Rule. Statistical Independence. Total Probability Theorem. Bayes' TheoremRandom Variables and Their DistributionsRandom VariablesProbability DistributionMain Descriptors of a Random VariableMean. Variance and Standard Deviation. Markov Inequality. Chebyshev Inequality. Skewness. Quantiles and PercentilesBrief Review of DistributionsDiscrete Distributions. Continuous DistributionsMultiple Random VariablesJoint Probability. Conditional Probability DistributionsCovariance and CorrelationFunctions of Random VariablesProbability DistributionsMain Descriptors of Random FunctionsRandom ProcessesDefinition of a Random ProcessMain Descriptors of Random ProcessMean Value. VarianceStationary Random ProcessesErgodicity of Random ProcessesCounting ProcessesRecurrent Point ProcessesMarkov ProcessSome Limit Results in Probability and Stochastic ProcessesLimit Theorems in Probability TheoryThe Central Limit Theorem. The Poisson Theorem. A Random Number of Random Variables in a SumStochastic ProcessesCrossing a "High Level" by Continuous Process. Thinning a Point ProcessThe Superposition of Point ProcessesSTATISTICAL INFERENCE CONCEPTSStatistical EstimationPoint EstimationMethod of Moments. Method of Maximum LikelihoodInterval EstimationHypothesis TestingFrequency HistogramGoodness-of-Fit TestsThe Chi-Square Test. The Kolmogorov-Smirnov Test. Sample ComparisonReliability Regression Model FittingGauss-Markov Theorem and Linear RegressionRegression Analysis. The Gauss-Markov Theorem. Multiple Linear RegressionProportional Hazard (PH) and Accelerated Life (AL) ModelsAccelerated Life (AL) Model. Proportional Hazard (PH) ModelAccelerated Life Regression for Constant StressAccelerated Life Regression for Time-Dependent StressPRACTICAL RELIABILITY CONCEPTSReliability MeasuresTime-to-Failure Distribution and Reliability FunctionMean Time to Failure and Percentile LifeFailure Rate and Cumulative Hazard FunctionLife Distributions as Reliability ModelsGeometric DistributionThe Binomial DistributionExponential DistributionClasses of Distribution Functions Based on AgingFailure Rate and the Notion of Aging. Bounds on Reliability for Aging Distributions. Inequality for Coefficient of Variation. Cumulative Damage ModelThe Weibu

Autoregressive modeling of wide-band indoor radio propagation

Abstract: Based on frequency domain measurements in the 0.9-1.1-GHz band, an autoregressive model for the frequency response of the indoor radio channel is introduced. It is shown that a second-order process is sufficient to represent the important statistical characteristics of the channel both in the frequency domain and the time domain where each pole identifies the arrival of a cluster of paths. A comparison is made between the statistical characteristics of the empirical data and of the channel responses regenerated from the second-order AR processes. Four methods to regenerate the indoor radio channel responses from a second-order AR model are proposed. The accuracy of the methods is examined by comparing the cumulative distribution functions of the RMS delay spread and the 3-dB width of the frequency correlation function with that of the measurements performed in global, local, and mixed indoor radio propagation experiments. >

Avalanche breakdown and the probabilistic nature of laser-induced damage

Abstract: This paper discusses the probabilistic nature of the damaging interaction between light and matter. It is shown that when one recognizes that there is some probability to induce damage at any level of optical irradiation, then the reported irreproducible damage-resistance properties of many useful materials can be understood. This point of view also explains why some optical components may be safely irradiated many times before damage occurs, though no other change in the material can be detected prior to the observation of damage. Experimental data showing the probability for surface damage as a function of power density are presented for several materials. The dependence of damage probability on optical field strength is similar to that of the dc ionization coefficients for semiconductors and gases on the applied field. This observation is discussed and it is suggested that a form of avalanche breakdown might be the cause of laser-induced damage.

Zero-Shot Event Detection Using Multi-modal Fusion of Weakly Supervised Concepts

Abstract: Current state-of-the-art systems for visual content analysis require large training sets for each class of interest, and performance degrades rapidly with fewer examples. In this paper, we present a general framework for the zeroshot learning problem of performing high-level event detection with no training exemplars, using only textual descriptions. This task goes beyond the traditional zero-shot framework of adapting a given set of classes with training data to unseen classes. We leverage video and image collections with free-form text descriptions from widely available web sources to learn a large bank of concepts, in addition to using several off-the-shelf concept detectors, speech, and video text for representing videos. We utilize natural language processing technologies to generate event description features. The extracted features are then projected to a common high-dimensional space using text expansion, and similarity is computed in this space. We present extensive experimental results on the large TRECVID MED [26] corpus to demonstrate our approach. Our results show that the proposed concept detection methods significantly outperform current attribute classifiers such as Classemes [34], ObjectBank [21], and SUN attributes[28] . Further, we find that fusion, both within as well as between modalities, is crucial for optimal performance.