A method is presented to divide the measured total congestion in any freeway section into three ‘slices’: (1) the delay that collisions cause; (2) the potential reduction in delay at bottlenecks that ideal ramp metering can achieve; and (3) the remaining delay, due mainly to excess demand, but also to all other causes, including non-collision incidents, lane closures, and weather. The method in...

In this paper, we present a linear dynamic stochastic optimization model for Air Traffic Flow Management (ATFM) that accounts for uncertainty in both airport and en route airspace capacity. Rather than analyzing this problem in its full generality, we focus on the case in which there is a single destination airport and a small number of arrival fixes subject to blockage or reduced capacity as a...

In the past few years, numerical weather models (NWM) have been investigated to improve mapping functions which are used for tropospheric delay modeling in VLBI and GPS data analyses. The Vienna Mapping Functions VMF are based on direct raytracing through NWM, and so they are able to exploit the full information provided in the NWM. On the other hand, the Isobaric Mapping Functions IMF are usin...

Water resources managers can benefit from accurate prediction of the availability of groundwater. In this project I present two models to predict groundwater levels in an unconfined shallow aquifer in the Searsville basin, part of the Jasper Ridge Biological Preserve. The input data (ie, features) for the models includes local weather, lake stage, and stream flow data, and moving averages of th...

The impact of GPS Zenith Total Delay (ZTD) measurements on mesoscale weather forecasts is studied. GPS observations from a permanent European network are assimilated into the Penn State/NCAR Mesoscale Model (MM5) using its three-dimensional variational assimilation (3DVAR) system. The case study focuses on a snow storm that occurred during the period of 14-15 December 2001 over the western Medi...

Low-level wind shear, especially a microburst, is very hazardous to aircraft departing or approaching an airport. The danger became especially clear in a series of fatal commercial airliner accidents in the 1970s and 1980s at U.S. airports. In response, the Federal Aviation Agency (FAA) developed and deployed three ground-based lowaltitude wind-shear detection systems: the Low Altitude Wind She...

En route airspace congestion, often due to convective weather, causes system-wide delays and disruption in the U.S. National Airspace System (NAS). Today’s methods for managing congestion are mostly manual, based on uncertain forecasts of weather and traffic demand, and often involve rerouting or delaying entire flows of aircraft. A new, incremental decision-making approach is proposed, in whic...

Recent research has produced stochastic optimization models for adjusting traffic flows in response to predicted congestion in the enroute airspace. These models simultaneously consider a set of options for each flight that includes both the possibility of ground delay and reroutes. They take into account a distribution of possible weather scenarios and their outputs include alternate courses o...

Broadband satellite-based IP networks have been considered as the technology to enable a strong and promising next-generation market. In satellite communication systems, the channel performance might be severely degraded due to the dynamic weather conditions such as the precipitation, and thereby lead to network congestion. Therefore, congestion control is critical in such networks to satisfy Q...