Satellite Navigation for the Age of Autonomy

Global Navigation Satellite Systems (GNSS) brought navigation to the masses. Coupled with smartphones, the blue dot in the palm of our hands has forever changed the way we interact with the world. Looking forward, cyber-physical systems such as self-driving cars and aerial mobility are pushing the limits of what localization technologies including GNSS can provide. This autonomous revolution requires a solution that supports safety-critical operation, centimeter positioning, and cyber-security for millions of users. To meet these demands, we propose a navigation service from Low Earth Orbiting (LEO) satellites which deliver precision in-part through faster motion, higher power signals for added robustness to interference, constellation autonomous integrity monitoring for integrity, and encryption / authentication for resistance to spoofing attacks. This paradigm is enabled by the 'New Space' movement, where highly capable satellites and components are now built on assembly lines and launch costs have decreased by more than tenfold. Such a ubiquitous positioning service enables a consistent and secure standard where trustworthy information can be validated and shared, extending the electronic horizon from sensor line of sight to an entire city. This enables the situational awareness needed for true safe operation to support autonomy at scale.Comment: 11 pages, 8 figures, 2020 IEEE/ION Position, Location and Navigation Symposium (PLANS

Direct Inference of SNP Heterozygosity Rates and Resolution of LOH Detection

Single nucleotide polymorphisms (SNPs) have been increasingly utilized to investigate somatic genetic abnormalities in premalignancy and cancer. LOH is a common alteration observed during cancer development, and SNP assays have been used to identify LOH at specific chromosomal regions. The design of such studies requires consideration of the resolution for detecting LOH throughout the genome and identification of the number and location of SNPs required to detect genetic alterations in specific genomic regions. Our study evaluated SNP distribution patterns and used probability models, Monte Carlo simulation, and real human subject genotype data to investigate the relationships between the number of SNPs, SNP HET rates, and the sensitivity (resolution) for detecting LOH. We report that variances of SNP heterozygosity rate in dbSNP are high for a large proportion of SNPs. Two statistical methods proposed for directly inferring SNP heterozygosity rates require much smaller sample sizes (intermediate sizes) and are feasible for practical use in SNP selection or verification. Using HapMap data, we showed that a region of LOH greater than 200 kb can be reliably detected, with losses smaller than 50 kb having a substantially lower detection probability when using all SNPs currently in the HapMap database. Higher densities of SNPs may exist in certain local chromosomal regions that provide some opportunities for reliably detecting LOH of segment sizes smaller than 50 kb. These results suggest that the interpretation of the results from genome-wide scans for LOH using commercial arrays need to consider the relationships among inter-SNP distance, detection probability, and sample size for a specific study. New experimental designs for LOH studies would also benefit from considering the power of detection and sample sizes required to accomplish the proposed aims

Quantification of the performance of iterative and non-iterative computational methods of locating partial discharges using RF measurement techniques

Partial discharge (PD) is an electrical discharge phenomenon that occurs when the insulation materialof high voltage equipment is subjected to high electric field stress. Its occurrence can be an indication ofincipient failure within power equipment such as power transformers, underground transmission cableor switchgear. Radio frequency measurement methods can be used to detect and locate discharge sourcesby measuring the propagated electromagnetic wave arising as a result of ionic charge acceleration. Anarray of at least four receiving antennas may be employed to detect any radiated discharge signals, thenthe three dimensional position of the discharge source can be calculated using different algorithms. These algorithms fall into two categories; iterative or non-iterative. This paper evaluates, through simulation, the location performance of an iterative method (the standardleast squares method) and a non-iterative method (the Bancroft algorithm). Simulations were carried outusing (i) a "Y" shaped antenna array and (ii) a square shaped antenna array, each consisting of a four-antennas. The results show that PD location accuracy is influenced by the algorithm's error bound, thenumber of iterations and the initial values for the iterative algorithms, as well as the antenna arrangement for both the non-iterative and iterative algorithms. Furthermore, this research proposes a novel approachfor selecting adequate error bounds and number of iterations using results of the non-iterative method, thus solving some of the iterative method dependencies

GUARDRAIL SYSTEM

To reduce the tendency for high center of mass vehicles to roll or vault over a guardrail barrier or dive under it, the guardrail barrier has outer curved portions selected to adjust the moment of inertia of the guardrail barrier by providing a sufficiently high moment of inertia to slow the vehicle but sufficiently low to avoid excessive force against the occupant compartment. A central portion connecting the outer curves sized to provide an effective depth of 12.25 inches to capture high bumper vehicles and small vehicles and an area of 1.99 inches to provide rigidity enough to the curved portions to avoid flattening and penetration. The outer curves of asymmetrical

A protocol for a scoping review of equity measurement in mental health care for children and youth

Background: Mental health (MH) problems are among the most important causes of morbidity and mortality for children and youth. Problems of lack of equity in child and youth MH services (CYMHS)-including, but not limited to, problems in inaccessibility and quality of services-are widespread. Characterizing the nature of equity in CYMHS is an ongoing challenge because the field lacks a consistent approach to conceptualizing equity. We will conduct a scoping review of how equity in MH services for children and youth has been defined, operationalized, and measured. Our objectives are to discover: (1) What conceptual definitions of equity are used by observational studies of CYMHS?; (2) What service characteristics of CYMHS care do indices of equity cover?; (3) What population dimensions have been used to operationalize equity?; (4) What statistical constructs have been used in indices that measure CYMHS equity?; and (5) What were the numerical values of those indices? Methods: The following databases will be searched: Medline, Embase, PsycINFO, Cochrane Controlled Register of Trials, CINAHL, EconLit, and Sociological Abstracts. Searches will be conducted from the date of inception to the end of the last full calendar year (December 2019). Studies will be included if they include an evaluation of a mental health service for children or youth (defined as those under 19 years of age) and which quantify variation in some aspect of child or youth mental health services (e.g., accessibility, volume, duration, or quality) as a function of socio-demographic and/or geographic variables. Study selection will occur over two stages. Stage one will select articles based on title and abstract using the liberal-accelerated method. Stage two will review the full texts of selected titles. Two reviewers will work independently on full-text reviewing, with each study screened twice using pre-specified eligibility criteria. One reviewer will chart study characteristics and indices to be verified by a second reviewer. Reviewers will resolve full-text screening and data extraction disagreements through discussion. Synthesis of the collected data will focus on compiling and mapping the types and characteristics of the indices used to evaluate MH services equity. Discussion: The planned, systematic scoping review will survey the literature regarding how equity in MH services for children and youth has been operationalized and help inform future studies of equity in CYMHS. Systematic review registration: Open Science Foundation ID SYSR-D-19-00371, https://osf.io/58srv/

A protocol for a scoping review of equity measurement in mental health care for children and youth

Background: Mental health (MH) problems are among the most important causes of morbidity and mortality for children and youth. Problems of lack of equity in child and youth MH services (CYMHS)-including, but not limited to, problems in inaccessibility and quality of services-are widespread. Characterizing the nature of equity in CYMHS is an ongoing challenge because the field lacks a consistent approach to conceptualizing equity. We will conduct a scoping review of how equity in MH services for children and youth has been defined, operationalized, and measured. Our objectives are to discover: (1) What conceptual definitions of equity are used by observational studies of CYMHS?; (2) What service characteristics of CYMHS care do indices of equity cover?; (3) What population dimensions have been used to operationalize equity?; (4) What statistical constructs have been used in indices that measure CYMHS equity?; and (5) What were the numerical values of those indices? Methods: The following databases will be searched: Medline, Embase, PsycINFO, Cochrane Controlled Register of Trials, CINAHL, EconLit, and Sociological Abstracts. Searches will be conducted from the date of inception to the end of the last full calendar year (December 2019). Studies will be included if they include an evaluation of a mental health service for children or youth (defined as those under 19 years of age) and which quantify variation in some aspect of child or youth mental health services (e.g., accessibility, volume, duration, or quality) as a function of socio-demographic and/or geographic variables. Study selection will occur over two stages. Stage one will select articles based on title and abstract using the liberal-accelerated method. Stage two will review the full texts of selected titles. Two reviewers will work independently on full-text reviewing, with each study screened twice using pre-specified eligibility criteria. One reviewer will chart study characteristics and indices to be verified by a second reviewer. Reviewers will resolve full-text screening and data extraction disagreements through discussion. Synthesis of the collected data will focus on compiling and mapping the types and characteristics of the indices used to evaluate MH services equity. Discussion: The planned, systematic scoping review will survey the literature regarding how equity in MH services for children and youth has been operationalized and help inform future studies of equity in CYMHS. Systematic review registration: Open Science Foundation ID SYSR-D-19-00371, https://osf.io/58srv/

The Age Of Globular Clusters In Light Of Hipparcos: Resolving the Age Problem?

We review five independent techniques which are used to set the distance scale to globular clusters, including subdwarf main sequence fitting utilizing the recent Hipparcos parallax catalogue. These data together all indicate that globular clusters are farther away than previously believed, implying a reduction in age estimates. This new distance scale estimate is combined with a detailed numerical Monte Carlo study designed to assess the uncertainty associated with the theoretical age-turnoff luminosity relationship in order to estimate both the absolute age and uncertainty in age of the oldest globular clusters. Our best estimate for the mean age of the oldest globular clusters is now $11.5\pm 1.3$Gyr, with a one-sided, 95% confidence level lower limit of 9.5 Gyr. This represents a systematic shift of over 2 $\sigma$ compared to our earlier estimate, due completely to the new distance scale---which we emphasize is not just due to the Hipparcos data. This now provides a lower limit on the age of the universe which is consistent with either an open universe, or a flat, matter dominated universe (the latter requiring H_0 \le 67 \kmsmpc). Our new study also explicitly quantifies how remaining uncertainties in the distance scale and stellar evolution models translate into uncertainties in the derived globular cluster ages. Simple formulae are provided which can be used to update our age estimate as improved determinations for various quantities become available.Comment: 41 pages, including 10 eps figs, uses aaspp4.sty and flushrt.sty, submitted to Ap.J., revised to incorporate FULL Hipparcos catalogue dat