Safety Analysis Methods for Complex Systems in Aviation

Each new concept of operation and equipment generation in aviation becomes more automated, integrated and interconnected. In the case of Unmanned Aircraft Systems (UAS), this evolution allows drastically decreasing aircraft weight and operational cost, but these benefits are also realized in highly automated manned aircraft and ground Air Traffic Control (ATC) systems. The downside of these advances is overwhelmingly more complex software and hardware, making it harder to identify potential failure paths. Although there are mandatory certification processes based on broadly accepted standards, such as ARP4754 and its family, ESARR 4 and others, these standards do not allow proof or disproof of safety of disruptive technology changes, such as GBAS Precision Approaches, Autonomous UAS, aircraft self-separation and others. In order to leverage the introduction of such concepts, it is necessary to develop solid knowledge on the foundations of safety in complex systems and use this knowledge to elaborate sound demonstrations of either safety or unsafety of new system designs. These demonstrations at early design stages will help reducing costs both on development of new technology as well as reducing the risk of such technology causing accidents when in use. This paper presents some safety analysis methods which are not in the industry standards but which we identify as having benefits for analyzing safety of advanced technological concepts in aviation

1962: Abilene Christian College Bible Lectures - Full Text

THE RESTORATION PRINCIPLE” Being the Abilene Christian College Annual Bible Lectures 1962 Price: $3.95 Published by ABILENE CHRISTIAN COLLEGE STUDENTS EXCHANGE ACC Station Abilene, Texa

The role of epigenetic dysregulation in the epidemic of allergic disease

The epidemic of allergic disease in early life is one of the clearest indicators that the developing immune system is vulnerable to modern environmental changes. A range of environmental exposures epidemiologically associated with allergic disease have been shown to have effects on the foetal immune function in pregnancy, including microbial burden, dietary changes and environmental pollutants. Preliminary studies now suggest that these early effects on immune development may be mediated epigenetically through a variety of processes that collectively modify gene expression and allergic susceptibility and that these effects are potentially heritable across generations. It is also possible that rising rates of maternal allergy, a recognised direct risk factor for infant allergic disease, may be further amplifying the effects of environmental changes. Whilst effective prevention strategies are the ultimate goal in reversing the allergy epidemic, the specific environmental drivers, target genes, and intracellular pathways and mechanisms of early life immune programming are still unclear. It is hoped that identifying genes that are differentially regulated in association with subsequent allergic disease will assist in identifying causal pathways and upstream contributing environmental factors. In this way, epigenetic paradigms are likely to provide valuable insights into how the early environment can be modified to more favourably drive immune development and reverse the allergic epidemic

Main nutrient patterns and colorectal cancer risk in the European Prospective Investigation into Cancer and Nutrition study.

BACKGROUND: Much of the current literature on diet-colorectal cancer (CRC) associations focused on studies of single foods/nutrients, whereas less is known about nutrient patterns. We investigated the association between major nutrient patterns and CRC risk in participants of the European Prospective Investigation into Cancer and Nutrition (EPIC) study. METHODS: Among 477 312 participants, intakes of 23 nutrients were estimated from validated dietary questionnaires. Using results from a previous principal component (PC) analysis, four major nutrient patterns were identified. Hazard ratios (HRs) and 95% confidence intervals (CIs) were computed for the association of each of the four patterns and CRC incidence using multivariate Cox proportional hazards models with adjustment for established CRC risk factors. RESULTS: During an average of 11 years of follow-up, 4517 incident cases of CRC were documented. A nutrient pattern characterised by high intakes of vitamins and minerals was inversely associated with CRC (HR per 1 s.d.=0.94, 95% CI: 0.92-0.98) as was a pattern characterised by total protein, riboflavin, phosphorus and calcium (HR (1 s.d.)=0.96, 95% CI: 0.93-0.99). The remaining two patterns were not significantly associated with CRC risk. CONCLUSIONS: Analysing nutrient patterns may improve our understanding of how groups of nutrients relate to CRC

Considerations on Aviation Standards for Simultaneous Independent and Dependent Parallel Approaches

Required Navigation Performance (RNP) procedures to parallel runways that include curved approaches offer many benefits to the flying public, airlines, and nearby residents on the ground. Fewer track miles are required during approach, thus enabling decreases in missed connections, fuel burn, emissions, and noise footprint. This paper documents research on independent and dependent RNP approaches to parallel runways. The goals are to provide recommendations to support the International Civil Aviation Organization (ICAO) rule changes and to promote the growth of these RNP-enabled procedures around the world. The paper will be structured as follows: After pointing out the benefits that curved RNP procedures provide at parallel runway environments, we will summarize and compare current ICAO and Federal Aviation Administration (FAA) rules for simultaneous approach operations as well as proposed revisions of ICAO’s guidelines. We conclude that current ICAO standards and their proposed revisions will not fully reflect the changes needed to achieve all of the benefits that curved RNP procedures can provide in parallel runway environments. Accordingly, we will identify areas within the guidelines that need to be extended for this purpose. We will then describe two methodologies to enable safe RNP procedures to parallel runways that include curved approaches. Those two methodologies are based on safety concepts that were developed for RNP-established procedures at Seattle and safety concepts developed for Frankfurt Airport. Finally, we will conclude with possible ways to extend ICAO’s guidelines based on these concepts and identify further aspects that need to be considered, such as the potential of nuisance Traffic Alert and Collision Avoidance System (TCAS) alerts

Parallel approaches for singular value decomposition as applied to robotic manipulator Jacobians

Includes bibliographical references (pages 33-35).The system of equations that govern kinematically redundant robotic manipulators is commonly solved by finding the singular value decomposition (SVD) of the corresponding Jacobian matrix. This can require a considerable amount of time to compute, thus a parallel SVD algorithm reducing execution time is sought. The approach employed here lends itself to parallelization by using Givens rotations and information from previous decompositions. The key contribution of this research is the presentation and implementation of parallel SVD algorithms to compute the SVD for a set of Jacobians that represent various different joint failure scenarios. Results from implementation of the algorithm on a MasPar MP-1, an IBM SP2, and the PASM prototype parallel computers are compared. Specific issues considered for each implementation include: how data is mapped to the processing elements, the effect that increasing the number of processing elements has on execution time, the type of parallel architecture used, and trade-offs between modes of parallelism

Can Explanatory Style be Scored from TAT Protocols?

Explanatory style is a cognitive personality variable reflecting how people habitually explain the causes of bad events that involve themselves. Usually measured with a questionnaire, it can also be scored from verbal material such as interviews and essays. Unexplored to date is whether explanatory style can be assessed from stories written in response to pictures. College students (N = 108) completed the Expanded Attributional Style Questionnaire (EASQ) and the Beck Depression Inventory (BDJ) and responded to four Thematic Apperception Test (TAT) pictures chosen to elicit negative themes. Causal explanations were identified in the TAT protocols and reliably rated along the attributional dimensions of stability and globality. These ratings were consistent within subjects, and they correlated with the BDI. They correlated with globality as measured by the EASQ but not with stability.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68565/2/10.1177_0146167294201010.pd