181,064 research outputs found
Flight-Deck Interval Management in Near-Term Arrival Operations
A simulation investigated NASA Air Traffic Management Technology Demonstration 1 (ATD-1) procedures and prototype technologies, including the Traffic Management Advisor for Terminal Metering, Controller-Managed Spacing tools, and Flight Deck Interval Management (FIM) equipment. The ATD-1 procedures and technologies comprise an integrated solution for managing high-density arrivals that NASA is developing and transferring to government and industry stakeholders for NextGen. During each of eighteen simulation trials, experienced controllers managed approximately two hundred departures and over-flights together with seventy-five arrivals to Phoenix Sky Harbor International Airport in a realistic near-term environment. Eight of the arrivals were desktop-based flight simulators flown by airline pilots, which were equipped with prototype FIM equipment in two-thirds of the trials. The simulation provided system-level measures of performance of the ATD-1 integrated arrival solution, demonstrating high conformance with Performance-Based Navigation procedures and a low rate of FIM interruptions. FIM operations provided benefits under specific conditions when FIM aircraft flew connected routes to the runway. This paper focuses on the integration of FIM with the ATD-1 ground-based technologies, discusses outstanding issues, and describes avenues for further research
Synergizing Roadway Infrastructure Investment with Digital Infrastructure for Infrastructure-Based Connected Vehicle Applications: Review of Current Status and Future Directions
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.The safety, mobility, environmental and economic benefits of Connected and Autonomous Vehicles (CAVs) are potentially dramatic. However, realization of these benefits largely hinges on the timely upgrading of the existing transportation system. CAVs must be enabled to send and receive data to and from other vehicles and drivers (V2V communication) and to and from infrastructure (V2I communication). Further, infrastructure and the transportation agencies that manage it must be able to collect, process, distribute and archive these data quickly, reliably, and securely. This paper focuses on current digital roadway infrastructure initiatives and highlights the importance of including digital infrastructure investment alongside more traditional infrastructure investment to keep up with the auto industry's push towards this real time communication and data processing capability. Agencies responsible for transportation infrastructure construction and management must collaborate, establishing national and international platforms to guide the planning, deployment and management of digital infrastructure in their jurisdictions. This will help create standardized interoperable national and international systems so that CAV technology is not deployed in a haphazard and uncoordinated manner
VANET Applications: Hot Use Cases
Current challenges of car manufacturers are to make roads safe, to achieve
free flowing traffic with few congestions, and to reduce pollution by an
effective fuel use. To reach these goals, many improvements are performed
in-car, but more and more approaches rely on connected cars with communication
capabilities between cars, with an infrastructure, or with IoT devices.
Monitoring and coordinating vehicles allow then to compute intelligent ways of
transportation. Connected cars have introduced a new way of thinking cars - not
only as a mean for a driver to go from A to B, but as smart cars - a user
extension like the smartphone today. In this report, we introduce concepts and
specific vocabulary in order to classify current innovations or ideas on the
emerging topic of smart car. We present a graphical categorization showing this
evolution in function of the societal evolution. Different perspectives are
adopted: a vehicle-centric view, a vehicle-network view, and a user-centric
view; described by simple and complex use-cases and illustrated by a list of
emerging and current projects from the academic and industrial worlds. We
identified an empty space in innovation between the user and his car:
paradoxically even if they are both in interaction, they are separated through
different application uses. Future challenge is to interlace social concerns of
the user within an intelligent and efficient driving
Handover Management in Highly Dense Femtocellular Networks
For dense femtocells, intelligent integrated femtocell/macrocell network
architecture, a neighbor cell list with a minimum number of femtocells,
effective call admission control (CAC), and handover processes with proper
signaling are the open research issues. An appropriate traffic model for the
integrated femtocell/macrocell network is also not yet developed. In this
paper, we present the major issue of mobility management for the integrated
femtocell/macrocell network. We propose a novel algorithm to create a neighbor
cell list with a minimum, but appropriate, number of cells for handover. We
also propose detailed handover procedures and a novel traffic model for the
integrated femtocell/macrocell network. The proposed CAC effectively handles
various calls. The numerical and simulation results show the importance of the
integrated femtocell/macrocell network and the performance improvement of the
proposed schemes. Our proposed schemes for dense femtocells will be very
effective for those in research and industry to implement
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