Lockheed Martin (Canada)

A memory-based network that provides estimates of continuous variables and converges to the underlying (linear or nonlinear) regression surface is described. The general regression neural network (GRNN) is a one-pass learning algorithm with a highly parallel structure. It is shown that, even with sparse data in a multidimensional measurement space, the algorithm provides smooth transitions from one observed value to another. The algorithmic form can be used for any regression problem in which an assumption of linearity is not justified.

Diatoms are unicellular algae with plastids acquired by secondary endosymbiosis. They are responsible for approximately 20% of global carbon fixation. We report the 34 million-base pair draft nuclear genome of the marine diatom Thalassiosira pseudonana and its 129 thousand-base pair plastid and 44 thousand-base pair mitochondrial genomes. Sequence and optical restriction mapping revealed 24 diploid nuclear chromosomes. We identified novel genes for silicic acid transport and formation of silica-based cell walls, high-affinity iron uptake, biosynthetic enzymes for several types of polyunsaturated fatty acids, use of a range of nitrogenous compounds, and a complete urea cycle, all attributes that allow diatoms to prosper in aquatic environments.

Fresh fracture surfaces of the martian meteorite ALH84001 contain abundant polycyclic aromatic hydrocarbons (PAHs). These fresh fracture surfaces also display carbonate globules. Contamination studies suggest that the PAHs are indigenous to the meteorite. High-resolution scanning and transmission electron microscopy study of surface textures and internal structures of selected carbonate globules show that the globules contain fine-grained, secondary phases of single-domain magnetite and Fe-sulfides. The carbonate globules are similar in texture and size to some terrestrial bacterially induced carbonate precipitates. Although inorganic formation is possible, formation of the globules by biogenic processes could explain many of the observed features, including the PAHs. The PAHs, the carbonate globules, and their associated secondary mineral phases and textures could thus be fossil remains of a past martian biota.

The primary problem dealt with in this paper is the following. Given some description of a visual object, find that object in an actual photograph. Part of the solution to this problem is the specification of a descriptive scheme, and a metric on which to base the decision of "goodness" of matching or detection.

A series of lectures on the role of nonlinear processes in physics, mathematics, electrical engineering, physiology, and communication theory.From the preface:For some time I have been interested in a group of phenomena depending upon random processes. One the one hand, I have recorded the random shot effect as a suitable input for testing nonlinear circuits. On the other hand, for some of the work that Professor W. A. Rosenblith and I have been doing concerning the nature of the electroencephalogram, and in particular of the alpha rhythm, it has occurred to me to use the model of a system of random nonlinear oscillators excited by a random input...At the beginning we had contemplated a series of only four or five lectures. My ideas developed pari passu with the course, and by the end of the term we found ourselves with a set of fifteen lectures. The last few of these were devoted to the application of my ideas to problems in the statistical mechanics of gases. This work is both new and tentative, and I found that I had to supplement my course by the writing over of these with the help of Professer Y. W. Lee.

under 1 sun. The h-LAH-based solar still also exhibits long-term durability and antifouling functionality toward complex ionic contaminants.

ABSTRACT From the existing literature, it is not clear what effect financing constraints have on the sensitivities of firms' investment to their cash flow. I propose an explanation that reconciles the conflicting empirical evidence. I present two models: the unconstrained model, in which firms can raise external funds, and the constrained model, in which firms cannot do so. Using low dividends to identify financing constraints in my generated panel of data produces results consistent with those of Fazzari, Hubbard, and Petersen; using the constrained model produces results consistent with those of Kaplan and Zingales.

Static Stability and Control General Equations of Unsteady Motion The Stability Derivatives Stability of Uncontrolled Motion Response to Actuation of the Controls-Open Loop Closed-Loop Control Appendices: Analytical Tools Data for Estimating Aerodynamic Derivatives Mean Aerodynamic Chord, Mean Aerodynamic Center, and CMACW Standard Atmosphere and Other Data Data for the Boeing 747-100.

The multitarget recursive Bayes nonlinear filter is the theoretically optimal approach to multisensor-multitarget detection, tracking, and identification. For applications in which this filter is appropriate, it is likely to be tractable for only a small number of targets. In earlier papers we derived closed-form equations for an approximation of this filter based on propagation of a first-order multitarget moment called the probability hypothesis density (PHD). In a recent paper, Erdinc, Willett, and Bar-Shalom argued for the need for a PHD-type filter which remains first-order in the states of individual targets, but which is higher-order in target number. In this paper we show that this is indeed possible. We derive a closed-form cardinalized PHD (CPHD) filter, which propagates not only the PHD but also the entire probability distribution on target number.

No abstract available.

The preatmospheric mass of the Tagish Lake meteoroid was about 200,000 kilograms. Its calculated orbit indicates affinity to the Apollo asteroids with a semimajor axis in the middle of the asteroid belt, consistent with a linkage to low-albedo C, D, and P type asteroids. The mineralogy, oxygen isotope, and bulk chemical composition of recovered samples of the Tagish Lake meteorite are intermediate between CM and CI meteorites. These data suggest that the Tagish Lake meteorite may be one of the most primitive solar system materials yet studied.

Aim This executive summary of the hypertrophic cardiomyopathy clinical practice guideline provides recommendations and algorithms for clinicians to diagnose and manage hypertrophic cardiomyopathy in adult and pediatric patients as well as supporting documentation to encourage their use. Methods A comprehensive literature search was conducted from January 1, 2010, to April 30, 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases. Structure Many recommendations from the earlier hypertrophic cardiomyopathy guidelines have been updated with new evidence or a better understanding of earlier evidence. This summary operationalizes the recommendations from the full guideline and presents a combination of diagnostic work-up, genetic and family screening, risk stratification approaches, lifestyle modifications, surgical and catheter interventions, and medications that constitute components of guideline directed medical therapy. For both guideline-directed medical therapy and other recommended drug treatment regimens, the reader is advised to follow dosing, contraindications and drug-drug interactions based on product insert materials.

Photometric and spectroscopic observations of 110 cool white dwarf stars are presented and analyzed with state-of-the-art model atmosphere calculations appropriate for cool white dwarfs with pure hydrogen and pure helium, as well as mixed H/He compositions. High signal-to-noise spectroscopy reveals the presence of Hα in 20 white dwarfs previously classified as DC stars, four of which are magnetic. Cool white dwarfs are shown to form a narrow sequence in both color-color and color-magnitude diagrams, with little evidence for separation between hydrogen- and helium-rich compositions in these diagrams. The observed energy distributions are obtained from a combination of both optical BVRI and infrared JHK photometric data and used to derive both the effective temperature and the atmospheric composition of each star. Stellar masses are also obtained for 60 white dwarfs with known trigonometric parallaxes. Some discrepancies between the observed energy distributions and those predicted by the model atmospheres are described. In particular, evidence for the presence of a UV opacity source in the coolest hydrogen-rich white dwarfs is interpreted in terms of a pseudo continuum opacity originating from the Lyman edge.

We present a comparative study between a complex Wavelet Coefficient Shrinkage (WCS) filter and several standard speckle filters that are widely used in the radar imaging community. The WCS filter is based on the use of Symmetric Daubechies wavelets which share the same properties as the real Daubechies wavelets but with an additional symmetry property. The filtering operation is an elliptical soft- thresholding procedure with respect to the principal axes of the 2D complex wavelet coefficient distributions. Both qualitative and quantitative results (signal to mean square error ratio, equivalent number of looks, edgemap figure of merit) are reported. Tests have been performed using simulated speckle noise as well as real radar images. It is found that the WCS filter performs equally well as the standard filters for low-level noise and slightly outperforms them for higher-level noise.

article Free AccessLogP: a practical model of parallel computation Authors: David E. Culler University of California, Berkeley University of California, BerkeleyView Profile , Richard M. Karp University of Washington, Seattle University of Washington, SeattleView Profile , David Patterson University of California, Berkeley University of California, BerkeleyView Profile , Abhijit Sahay Iris Financial Engineering and Systems, Inc. Iris Financial Engineering and Systems, Inc.View Profile , Eunice E. Santos Electrical Engineering and Computer Science Department, Lehigh University Electrical Engineering and Computer Science Department, Lehigh UniversityView Profile , Klaus Erik Schauser Computer Science Department, University of California, Sanat Barbara Computer Science Department, University of California, Sanat BarbaraView Profile , Ramesh Subramonian Lockheed Corp. Lockheed Corp.View Profile , Thorsten von Eicken Computer Science Department, Cornell University Computer Science Department, Cornell UniversityView Profile Authors Info & Claims Communications of the ACMVolume 39Issue 1101 November 1996pp 78–85https://doi.org/10.1145/240455.240477Published:01 November 1996Publication History 222citation2,315DownloadsMetricsTotal Citations222Total Downloads2,315Last 12 Months251Last 6 weeks10 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF

In this paper, we present measurements from two passes of the Polar spacecraft of intense electric and magnetic field structures associated with Alfven waves at and within the outer boundary of the plasma sheet at geocentric distances of 4–6 R E near local midnight. The electric field variations have maximum values exceeding 100 mV/m and are typically polarized approximately normal to the plasma sheet boundary. The electric field structures investigated vary over timescales (in the spacecraft frame) ranging from 1 to 30 s. They are associated with strong magnetic field fluctuations with amplitudes of 10–40 nT which lie predominantly in the plane of the plasma sheet and are perpendicular to the local magnetic field. The Poynting flux associated with the perturbation fields measured at these altitudes is about 1–2 ergs cm −2 s −1 and is directed along the average magnetic field direction toward the ionosphere. If the measured Poynting flux is mapped to ionospheric altitudes along converging magnetic field lines, the resulting energy flux ranges up to 100 ergs cm −2 s −1 . These strongly enhanced Poynting fluxes appear to occur in layers which are observed when the spacecraft is magnetically conjugate (to within a 1° mapping accuracy) to intense auroral structures as detected by the Polar UV Imager (UVI). The electron energy flux (averaged over a spatial resolution of 0.5° ) deposited in the ionosphere due to auroral electron beams as estimated from the intensity in the UVI Lyman‐Birge‐Hopfield‐long filters is 15–30 ergs cm −2 s −1 . Thus there is evidence that these electric field structures provide sufficient Poynting flux to power the acceleration of auroral electrons (as well as the energization of upflowing ions and Joule heating of the ionosphere). During some events the phasing and ratio of the transverse electric and magnetic field variations are consistent with earthward propagation of Alfven surface waves with phase velocities of 4000–10000 km/s. During other events the phase shifts between electric and magnetic fields suggest interference between upward and downward propagating Alfven waves. The E/B ratios are about an order of magnitude larger than typical values of c/Σ p , where Σ p is the height integrated Pedersen conductivity. The contribution to the total energy flux at these altitudes from Poynting flux associated with Alfven waves is comparable to or larger than the contribution from the particle energy flux and 1–2 orders of magnitude larger than that estimated from the large‐scale steady state convection electric field and field‐aligned current system.

The success of e-commerce for any company, especially if it is not a well-known name, is greatly dependent on the appropriate design of its Web site. This study investigates the determinants of an effective Web site. A literature survey indicated that the major categories of determinants are: page loading speed, business content, navigation efficiency, security and marketing/customer focus. The relative importance of each category was determined by counting the number of citations in the literature, and by soliciting the opinions of end users. The paper concentrates on experts' recommendations of how to create an effective Web site from an e-commerce point of view.

Background and Purpose —The reliability of the EuroQol and SF-36 questionnaires after stroke is not known. We therefore aimed to assess and compare the test-retest reliability of both instruments in a group of stroke patients. Methods —A total of 2253 patients with stroke entered by United Kingdom hospitals in the International Stroke Trial were randomized to follow up with either the EuroQol or the SF-36 instruments. For both instruments, we randomly selected one third of respondents and asked them to complete another, identical questionnaire. We assessed test-retest reliability using agreement statistics: unweighted κ statistics for the categorical domains of the EuroQol and intraclass correlation coefficients for the EuroQol visual analog scale, utility scores, and SF-36. Results —For the five categorical domains of the EuroQol, reproducibility was generally good (κ ranged from 0.63 to 0.80). The reproducibility of the domains of the SF-36 was qualitatively similar for all the domains except mental health (intraclass correlation coefficient=.28). However, the 95% confidence intervals for the difference in scores between test and retest were substantial. For both instruments, reproducibility was better when the patient completed the questionnaires than when a proxy did. Conclusions —Both the EuroQol and SF-36 have acceptable and qualitatively similar test-retest reliability. Therefore, either instrument might function effectively as a discriminatory measure for assessing health-related quality-of-life outcomes in groups of patients after stroke. However, our data do not support the use of either instrument for serial assessments in individual patients unless very large differences over time are expected.

Previous methods of two-wavelength variable-sensitivity interferometry are reviewed and a simplified two-wavelength technique for interferometric testing under static conditions is discussed. An extension of the static technique to real-time dynamic testing is proposed and an operational variable-sensitivity interferometer utilizing the real-time technique is described.

A solution is obtained for the case in which a sem-infinite crack suddenly appears and grows at constant velocity in a stretched elastic body. The problem, one of mixed boundary values on a half plane, is solved by transform methods including the Weiner-Hopf and Cagniard techniques. Among the graphical results presented is the time variation of the transverse stress at a fixed point on the line of fracture as the tip of the crack approaches. Asymptotic forms for the stresses near the crack tip are also obtained and are compared with results of other studies in crack propagation.