Implementing and Evaluating Alternative Airspace Rationing Methods

While airport congestion has long been viewed as a major air traffic management problem in the United States, congestion in the en route airspace is drawing an increasing amount of attention. Sources of en route congestion, such as severe weather, often cause the Federal Aviation Administration (FAA) to delay and reroute aircraft in order to ensure safety. Most current research into methods for managing en route congestion seeks to reduce delay or aid in aircraft rerouting. However, there has been less attention paid to delay and reroute allocation methods an area in which there appears to be a pressing, practical need.Collaborative Decision Making (CDM) is a movement within the air traffic management community that has combined the interests of the FAA and industry to develop a universally-accepted resource rationing process for congested airports. There is high expectation that CDM can achieve similar success in developing a parallel rationing process for the en route airspace. The CDM-inspired research underlying this thesis led to the development of a software tool, the En Route Resource Allocation Prototype (ERAP), that supports the analysis of alternative en route airspace rationing methods. In this thesis, we define a basic en route traffic flow management scenario, conduct experiments, and derive ERAP results which provide insight into rationing resources in the en route airspace domain. It is hoped that ERAP can serve as a baseline for future comparison and help lead to final industry acceptance of an ideal rationing solution

Pruning rules for optimal runway sequencing

This paper investigates runway sequencing for real world scenarios at one of the world's busiest airports, London Heathrow. Several pruning principles are introduced that enable significant reductions of the problem's average complexity, without compromising the optimality of the resulting sequences, nor compromising the modelling of important real world constraints and objectives. The pruning principles are generic and can be applied in a variety of heuristic, meta-heuristic or exact algorithms. They could also be applied to different runway configurations, as well as to different variants of the machine scheduling problem with sequence dependent setup times, the generic variant of the runway sequencing problem in this paper. They have been integrated into a dynamic program for runway sequencing, which has been shown to be able to generate optimal sequences for large scale problems at an extremely low computational cost, whilst considering complex non-linear and non-convex objective functions that offer significant flexibility to model real world preferences and real world constraints. The results shown here counter the proliferation of papers that claim that runway sequencing problems are too complex to solve exactly and therefore attempt to solve them heuristically

Price Discovery and the Accuracy of Consolidated Data Feeds in the U.S. Equity Markets

Both the scientific community and the popular press have paid much attention to the speed of the Securities Information Processor, the data feed consolidating all trades and quotes across the US stock market. Rather than the speed of the Securities Information Processor, or SIP, we focus here on its accuracy. Relying on Trade and Quote data, we provide various measures of SIP latency relative to high-speed data feeds between exchanges, known as direct feeds. We use first differences to highlight not only the divergence between the direct feeds and the SIP, but also the fundamental inaccuracy of the SIP. We find that as many as 60 percent or more of trades are reported out of sequence for stocks with high trade volume, therefore skewing simple measures such as returns. While not yet definitive, this analysis supports our preliminary conclusion that the underlying infrastructure of the SIP is currently unable to keep pace with the trading activity in today's stock market.Comment: 18 pages, 20 figures, 2 table

Children and parents’ perspectives of the impact of the COVID-19 pandemic on Ontario children’s physical activity, play, and sport behaviours

Background: The COVID-19 pandemic and associated public health measures have resulted in the closure of many physical activity-supporting facilities. This study examined Ontario parents’ and children’s perspectives of COVID-19’s impact on children’s physical activity behaviours, return to play/sport during COVID-19, as well as barriers/facilitators to getting active amid extended closures of physical activity venues. Methods: Parents/guardians of children aged 12 years and under living in Ontario, Canada were invited to participate in an interview. 12 parent/guardian and 9 child interviews were conducted via Zoom between December 2020 – January 2021, were audio-recorded, and transcribed verbatim. Thematic content analysis was undertaken to identify pronounced themes. Results: Themes for both parent and child interviews fell into one of three categories: 1) barriers and facilitators for getting children active amid COVID-19 closures of physical activity-supporting facilities; 2) changes in children’s activity levels; and, 3) perspectives on return to play/sport during and post-pandemic. Various subthemes were identified and varied between parents and children. The most common facilitator for dealing with children’s inactivity voiced by parents/guardians was getting active outdoors. Parents/guardians noted their willingness to have their children return to play/sport in the community once deemed safe by public health guidelines, and children’s willingness to return stemmed primarily from missing their friends and other important authority figures (e.g., coaches) and sporting events (e.g., tournaments). Conclusions: Findings from this study could inform families of feasible and realistic strategies for increasing children’s physical activity during community closures, while also providing public health experts with information regarding what supports, or infrastructure might be needed during future lockdown periods and/or pandemics

Airspace Technology Demonstration 2 (ATD-2): Fuser Why Everyone Should Have One

This presentation covers how a high level overview of the Fuser used on ATD-2

Parents’ Attitudes Regarding Their Children’s Play and Sport During COVID-19

The COVID-19 pandemic and associated public health measures have interrupted the daily routines of parents and children. The purpose of this study was to explore parents’ attitudes regarding their children’s play/sport during COVID-19. A secondary objective was to explore the influence of parent demographics and parent-reported physical activity levels and risk tolerance on these attitudes. Ontario parents of children aged 12 and younger completed an online survey (August—December 2020) that assessed their attitudes (grouped by support, safety and socialization-related attitudes; n = 14 items) regarding their child(ren)’s play/sport, their physical activity levels (n = 2 items), and demographic details (n = 16 items). Two open-ended items were used to gather a deeper understanding of attitudes. Parents’ tolerance for risk was measured via the validated Tolerance of Risk in Play Scale. Descriptive statistics were calculated to describe attitudes and risk tolerance. Least Absolute Shrinkage and Selection Operator regressions were conducted to examine factors influencing parents’ attitudes. Multiple linear models were computed using the identified predictors for each attitude category. Deductive content analysis was undertaken on open-ended responses. Participants (n = 819) reported the highest scores for safety-related attitude items (M = 3.54, SD = .63) followed by socialization and support, which all influenced attitudes regarding children’s play/sport (p \u3c .05). Demographics and parents’ physical activity levels were identified as important predictors of parents’ attitudes. Qualitative data revealed that parents had mixed levels of comfort with respect to their children’s return to play/sport. Findings from this study reveal that increased support is needed to guide future play/sport decision-making

Hepatic IKKε expression is dispensable for high-fat feeding-induced increases in liver lipid content and alterations in glucose tolerance

© 2020 the American Physiological Society. There are endocrine and immunological changes that occur during onset and progression of the overweight and obese states. The inhibitor of nuclear factor-κB kinase-ε (IKKε) was originally described as an inducible protein kinase; whole body gene deletion or systemic pharmaceutical targeting of this kinase improved insulin sensitivity and glucose tolerance in mice. To investigate the primary sites of action associated with IKKε during weight gain, we describe the first mouse line with conditional elimination of IKKε in the liver (IKKεAlb-/-). IKKεAlb-/- mice and littermate controls gain weight, show similar changes in body composition, and do not display any improvements in insulin sensitivity or whole body glucose tolerance. These studies were conducted using breeder chow diets and matched low- vs. high-fat diets. While glycogen accumulation in the liver is reduced in IKKεAlb-/- mice, lipid storage in liver is similar in IKKεAlb-/- mice and littermate controls. Our results using IKKεAlb-/-mice suggest that the primary action of this kinase to impact insulin sensitivity during weight gain lies predominantly within extrahepatic tissues