Receiver-Autonomous Spoofing Detection: Experimental Results of a Multi-antenna Receiver Defense Against a Portable Civil GPS Spoofer

In this work we demonstrate the use of a dual antenna receiver that employs a receiver-autonomous angle-ofarrival spoofing countermeasure. This defense is conjectured to be effective against all but the most sophisticated spoofing attempts. The technique is based on observation of L1 carrier differences between multiple antennas referenced to a common oscillator. We first employ a moderately sophisticated spoofer to "fool" a single-antenna civil receiver. We then deploy the same attack after augmenting the receiver with an additional antenna and with receiver-autonomous spoofdetection software. The work discusses the experimental results together with various issues related to sensitivity, probability of false alarm, impact of carrier multipath, line-bias-calibration, and physical setup and security. We suggest that this work is important to the community as it provides experimental validation of a low-cost technique for receiver-autonomous spoofing detection. Furthermore, the technique, when combined with physical security of the antenna installation, provides a strong defense against even a sophisticated attack. The receiver employed is an L1-only civil GPS receiver with multiple antenna capability. The GPS chipset employed is the venerable GP2015/GP2021 that has been freely available for over a decade. As such, this receiver is representative of many civil receivers in use today for a variety of applications. Multiple antennas are enabled either through multiple independent RF front ends and correlators or via antenna multiplexing into a single RF front end and correlator bank.Aerospace Engineering and Engineering Mechanic

Estimation de l'enveloppe et de la fréquence locales par les opérateurs de Teager-Kaiser en interférométrie en lumière blanche.

In this work, a new method for surface extraction in white light scanning interferometry (WLSI) is introduced. The proposed extraction scheme is based on the Teager-Kaiser energy operator and its extended versions. This non-linear class of operators is helpful to extract the local instantaneous envelope and frequency of any narrow band AM-FM signal. Namely, the combination of the envelope and frequency information, allows effective surface extraction by an iterative re-estimation of the phase in association with a new correlation technique, based on a recent TK crossenergy operator. Through the experiments, it is shown that the proposed method produces substantially effective results in term of surface extraction compared to the peak fringe scanning technique, the five step phase shifting algorithm and the continuous wavelet transform based method. In addition, the results obtained show the robustness of the proposed method to noise and to the fluctuations of the carrier frequency

Urban Poverty and Health in Developing Countries: Household and Neighborhood Effects

In the U.S. and other high-income countries, where most of the population lives in urban areas, there is intense scholarly and program interest in the effects of household and neighborhood living standards on health. Yet very few studies of developing-country cities have examined these issues. This paper investigates whether in these cities, the health of women and young children is influenced by both household and neighborhood standards of living. Using data from the urban samples of some 85 Demographic and Health surveys, and modelling living standards using factor-analytic MIMIC methods, we find, first, that the neighborhoods of poor households are more heterogeneous than is often asserted. To judge from our results, it appears that as a rule, poor urban households do not tend to live in uniformly poor communities; indeed, about 1 in 10 of a poor household's neighbors is relatively affluent, belonging to the upper quartile of the urban distribution of living standards. Do household and neighborhood living standards influence health? Applying multivariate models with controls for other socioeconomic variables, we discover that household living standards have a substantial influence on three measures of health: unmet need for modern contraception; birth attendance by doctors, nurses, or trained midwives; and children's height for age. Neighborhood living standards exert significant additional influence on health in many of the surveys we examine, especially in birth attendance. There is considerable evidence, then, indicating that both household and neighborhood living standards can make a substantively important difference to health.poverty, health, developing countries, urban, factor analysis, neighborhood

Super-resolution imaging within reach

Although several optical techniques have been recently developed in order to overcome the resolution limit in microscopy, the imaging of sub-wavelength features is still a real challenge. In practise, super-resolution techniques remain difficult to build or are photo-toxic for the biological samples. However, microsphere-assisted microscopy has recently made super-resolution imaging accessible to scientists (e.g. optical metrologists, engineers and biologists). This paper presents an easy-to-implement optical setup to perform full-field and contactless super-resolution measurements of nanostructured media or biological elements. For this purpose, a classical microscope was enhanced by introducing a transparent microsphere. We show that this rather simple approach makes it possible to achieve a lateral resolution of 200 nm in air, i.e. the visualization of feature sizes of 100 nm

Confessions of a Shoe Salesman and Florist

Every fellow consciously or subconsciously has his own individual rating scale for girls, including hair, figure, complexion, but I notice feet. Perhaps that is because for four years I\u27ve watched big and little, blonde and brunette, tramp, swing, or waddle into stores to buy shoes. After all, the way the foot is shod has a lot to do with the way a woman walks and the way a woman walks can be one of the most impressive-or depressive mannerisms about her. When I think how important posture is to the personality- how important a firm, sure step is down the path of life I marvel at some of the frabjous choices girls make. Why is it a tall girl invariably buys low he:!ls for every occasion, sacrificing grace and carriage, and a short girl generally chooses a French spike for a sport suit almost to the point of bordering on the ridiculous? I don\u27t know and never could figure out

Zero gravity tissue-culture laboratory

Hardware was developed for performing experiments to detect the effects that zero gravity may have on living human cells. The hardware is composed of a timelapse camera that photographs the activity of cell specimens and an experiment module in which a variety of living-cell experiments can be performed using interchangeable modules. The experiment is scheduled for the first manned Skylab mission

The Impact of 4 X 4 Block Scheduling at an Urban High School

The primary purpose of this study was to examine whether attendance, academic achievement, school climate, student stress, and teacher burnout improved in an inner city, predominantly African American high school after the implementation of a 4 x 4 block schedule. Data concerning student academic achievement and absenteeism in 14 classrooms were gathered from the school\u27s Annual Scholastic Reports. Data concerning the instructional practices of eight teachers were gathered through the teacher version of the Instructional Practices Survey and compared to a student version of the Instructional Practices Survey to determine whether student perception of instructional practices coincided with the teachers\u27 perceptions. Classroom climate was examined by administering the Classroom Environment Survey to seven teachers and 130 of their students. Student stress levels were examined from the results of the School Situation Survey returned by 106 students. The Maslach Burnout Inventory was used to gather data concerning the burnout levels of 13 teachers. This study found that increases in grade point average and decreases in absenteeism were not achieved after three years of block scheduling. Instructional practices of the teachers involved in this study did not change significantly. School climate, student stress levels, and teacher burnout were found to be in the average range

Discovering new solar systems : Jupiter analogs and the quest to find another Earth

textExoplanets are now known to be ubiquitous throughout the Galaxy. From the Kepler survey, we expect nearly every main-sequence star to form planetary systems during its formation phase. However, the detection limits of Kepler are confined to planets with short orbital periods, comparable to those in the inner solar system. Thanks to the long observational time baseline of the McDonald Observatory Radial Velocity (RV) Survey, we can identify gas giant planets in the outer regions of extrasolar planetary systems. The statistics of such planets are not well known, and are important for understanding the physics behind planet formation and migration. In this dissertation, I detail the discovery of five giant exoplanets on long-period orbits–so-called “Jupiter analogs.” For two systems of giant planets discovered through our survey, pairs of planets follow closely-packed orbits, creating the possibility for dynamical instability. I therefore examine the orbital resonances that allow these planets to avoid gravitational disruption. Because we see an abundance of small, potentially habitable exoplanets in the Kepler data set, current and upcoming exoplanet surveys concentrate on finding Earth-mass planets orbiting stars near enough to facilitate detailed follow-up observations. Particularly attractive targets are cool, low-mass “M dwarf” stars. Their low masses (and thus higher RV amplitudes from exoplanets) and close-in habitable zones allow for relatively quick detection of low-mass planets in the habitable zone. However, the RV signals of such planets will be obscured by stellar magnetic activity, which is poorly understood for M stars. In an effort to improve the planet detection capabilities of our M dwarf planet survey, I have conducted a detailed investigation of the magnetic behavior of our target stars. I show that, while stellar activity does not appear to systematically influence RV measurements above a precision level of ∼ 5 m/s, activity cycles can occasionally produce RV signals in excess of 10 m/s. Additionally, I show that long-term, solar-type stellar activity cycles are common amongst our M dwarf targets, although they are significantly less frequent than for FGK stars. In the case of GJ 328, I have discovered a magnetic activity cycle that appears in the RV data, causing the giant planet around the star to appear to be on a more circular orbit than indicated by the activity-corrected data. Such corrections are essential for the discovery of Earthlike exoplanets.Astronom

Empty reviews: a description and consideration of cochrane systematic reviews with no included studies

Journal ArticleBackground: There is no specific guidance for the reporting of Cochrane systematic reviews that do not have studies eligible for inclusion. As a result, the reporting of these so-called ‘‘empty reviews'' may vary across reviews. This research explores the incidence of empty systematic reviews in The Cochrane Database of Systematic Reviews (The CDSR) and describes their current characteristics. Methodology/Principal Findings: Empty reviews within The CDSR as of 15 August 2010 were identified, extracted, and coded for analysis. Review group, original publication year, and time since last update, as well as number of studies listed as excluded, awaiting assessment, or on-going within empty reviews were examined. 376 (8.7%) active reviews in The CDSR reported no included studies. At the time of data collection, 45 (84.9%) of the Cochrane Collaboration's 53 Review Groups sustained at least one empty review, with the number of empty reviews for each of these 45 groups ranging from 1 to 35 (2.2-26.9%). Time since original publication of empty reviews ranged from 0 to 15 years with a mean of 4.2 years (SD = 3.4). Time since last assessed as up-to-date ranged from 0 to 12 years with a mean of 2.8 years (SD = 2.2). The number of excluded studies reported in these reviews ranged from 0 to 124, with an average of 9.6 per review (SD = 14.5). Eighty-eight (23.4%) empty reviews reported no excluded studies, studies awaiting assessment, or on-going studies. Conclusions: There is a substantial number of empty reviews in The CDSR, and there is some variation in the reporting and updating of empty reviews across Cochrane Review Groups. This variation warrants further analysis, and may indicate a need to develop guidance for the reporting of empty systematic reviews in The CDSR

How trust and relationships impact on the giving decisions of philanthropists

Numerous studies have sought to understand why philanthropists are not giving more to charity. Two recently published studies identified a lack of faith in charities and an absence of trust as significant barriers to philanthropy. We report on the findings of a qualitative study which sought to examine the extent to which trust, and relationships influence the wealthy to give or withhold funding to charities. We employed in‐depth qualitative research methods and semi‐structured, conversational‐style, interviews as the major form of data collection. We utilised Braun and Clarke's ‘reflexive thematic analysis’ method of thematic analysis which gave rise to 4 key themes and 9 sub‐themes. Findings revealed that trust underpins the relationships that philanthropists have with charities and is an important conduit to forging an ongoing relationship. Trust is frequently relied upon as a proxy for evidence and an absence of trust will usually lead a philanthropist to withhold funding