Analysis of Factors for Incorporating User Preferences in Air Traffic Management: A system Perspective

NASA Technical Reports Server (NTRS)

Sheth, Kapil S.; Gutierrez-Nolasco, Sebastian

2010-01-01

This paper presents an analysis of factors that impact user flight schedules during air traffic congestion. In pre-departure flight planning, users file one route per flight, which often leads to increased delays, inefficient airspace utilization, and exclusion of user flight preferences. In this paper, first the idea of filing alternate routes and providing priorities on each of those routes is introduced. Then, the impact of varying planning interval and system imposed departure delay increment is discussed. The metrics of total delay and equity are used for analyzing the impact of these factors on increased traffic and on different users. The results are shown for four cases, with and without the optional routes and priority assignments. Results demonstrate that adding priorities to optional routes further improves system performance compared to filing one route per flight and using first-come first-served scheme. It was also observed that a two-hour planning interval with a five-minute system imposed departure delay increment results in highest delay reduction. The trend holds for a scenario with increased traffic.

Joint optimization of green vehicle scheduling and routing problem with time-varying speeds

PubMed Central

Zhang, Dezhi; Wang, Xin; Ni, Nan; Zhang, Zhuo

2018-01-01

Based on an analysis of the congestion effect and changes in the speed of vehicle flow during morning and evening peaks in a large- or medium-sized city, the piecewise function is used to capture the rules of the time-varying speed of vehicles, which are very important in modelling their fuel consumption and CO2 emission. A joint optimization model of the green vehicle scheduling and routing problem with time-varying speeds is presented in this study. Extra wages during nonworking periods and soft time-window constraints are considered. A heuristic algorithm based on the adaptive large neighborhood search algorithm is also presented. Finally, a numerical simulation example is provided to illustrate the optimization model and its algorithm. Results show that, (1) the shortest route is not necessarily the route that consumes the least energy, (2) the departure time influences the vehicle fuel consumption and CO2 emissions and the optimal departure time saves on fuel consumption and reduces CO2 emissions by up to 5.4%, and (3) extra driver wages have significant effects on routing and departure time slot decisions. PMID:29466370

Joint optimization of green vehicle scheduling and routing problem with time-varying speeds.

PubMed

Zhang, Dezhi; Wang, Xin; Li, Shuangyan; Ni, Nan; Zhang, Zhuo

2018-01-01

Based on an analysis of the congestion effect and changes in the speed of vehicle flow during morning and evening peaks in a large- or medium-sized city, the piecewise function is used to capture the rules of the time-varying speed of vehicles, which are very important in modelling their fuel consumption and CO2 emission. A joint optimization model of the green vehicle scheduling and routing problem with time-varying speeds is presented in this study. Extra wages during nonworking periods and soft time-window constraints are considered. A heuristic algorithm based on the adaptive large neighborhood search algorithm is also presented. Finally, a numerical simulation example is provided to illustrate the optimization model and its algorithm. Results show that, (1) the shortest route is not necessarily the route that consumes the least energy, (2) the departure time influences the vehicle fuel consumption and CO2 emissions and the optimal departure time saves on fuel consumption and reduces CO2 emissions by up to 5.4%, and (3) extra driver wages have significant effects on routing and departure time slot decisions.

Runway Operations Planning: A Two-Stage Solution Methodology

NASA Technical Reports Server (NTRS)

Anagnostakis, Ioannis; Clarke, John-Paul

2003-01-01

The airport runway is a scarce resource that must be shared by different runway operations (arrivals, departures and runway crossings). Given the possible sequences of runway events, careful Runway Operations Planning (ROP) is required if runway utilization is to be maximized. Thus, Runway Operations Planning (ROP) is a critical component of airport operations planning in general and surface operations planning in particular. From the perspective of departures, ROP solutions are aircraft departure schedules developed by optimally allocating runway time for departures given the time required for arrivals and crossings. In addition to the obvious objective of maximizing throughput, other objectives, such as guaranteeing fairness and minimizing environmental impact, may be incorporated into the ROP solution subject to constraints introduced by Air Traffic Control (ATC) procedures. Generating optimal runway operations plans was approached in with a 'one-stage' optimization routine that considered all the desired objectives and constraints, and the characteristics of each aircraft (weight class, destination, Air Traffic Control (ATC) constraints) at the same time. Since, however, at any given point in time, there is less uncertainty in the predicted demand for departure resources in terms of weight class than in terms of specific aircraft, the ROP problem can be parsed into two stages. In the context of the Departure Planner (OP) research project, this paper introduces Runway Operations Planning (ROP) as part of the wider Surface Operations Optimization (SOO) and describes a proposed 'two stage' heuristic algorithm for solving the Runway Operations Planning (ROP) problem. Focus is specifically given on including runway crossings in the planning process of runway operations. In the first stage, sequences of departure class slots and runwy crossings slots are generated and ranked based on departure runway throughput under stochastic conditions. In the second stage, the departure class slots are populated with specific flights from the pool of available aircraft, by solving an integer program. Preliminary results from the algorithm implementation on real-world traffic data are included.

Optimization of ramp area aircraft push back time windows in the presence of uncertainty

NASA Astrophysics Data System (ADS)

Coupe, William Jeremy

It is well known that airport surface traffic congestion at major airports is responsible for increased taxi-out times, fuel burn and excess emissions and there is potential to mitigate these negative consequences through optimizing airport surface traffic operations. Due to a highly congested voice communication channel between pilots and air traffic controllers and a data communication channel that is used only for limited functions, one of the most viable near-term strategies for improvement of the surface traffic is issuing a push back advisory to each departing aircraft. This dissertation focuses on the optimization of a push back time window for each departing aircraft. The optimization takes into account both spatial and temporal uncertainties of ramp area aircraft trajectories. The uncertainties are described by a stochastic kinematic model of aircraft trajectories, which is used to infer distributions of combinations of push back times that lead to conflict among trajectories from different gates. The model is validated and the distributions are included in the push back time window optimization. Under the assumption of a fixed taxiway spot schedule, the computed push back time windows can be integrated with a higher level taxiway scheduler to optimize the flow of traffic from the gate to the departure runway queue. To enable real-time decision making the computational time of the push back time window optimization is critical and is analyzed throughout.

Delay Banking for Managing Air Traffic

NASA Technical Reports Server (NTRS)

Green, Steve

2008-01-01

Delay banking has been invented to enhance air-traffic management in a way that would increase the degree of fairness in assigning arrival, departure, and en-route delays and trajectory deviations to aircraft impacted by congestion in the national airspace system. In delay banking, an aircraft operator (airline, military, general aviation, etc.) would be assigned a numerical credit when any of their flights are delayed because of an air-traffic flow restriction. The operator could subsequently bid against other operators competing for access to congested airspace to utilize part or all of its accumulated credit. Operators utilize credits to obtain higher priority for the same flight, or other flights operating at the same time, or later, in the same airspace, or elsewhere. Operators could also trade delay credits, according to market rules that would be determined by stakeholders in the national airspace system. Delay banking would be administered by an independent third party who would use delay banking automation to continually monitor flights, allocate delay credits, maintain accounts of delay credits for participating airlines, mediate bidding and the consumption of credits of winning bidders, analyze potential transfers of credits within and between operators, implement accepted transfers, and ensure fair treatment of all participating operators. A flow restriction can manifest itself in the form of a delay in assigned takeoff time, a reduction in assigned airspeed, a change in the position for the aircraft in a queue of all aircraft in a common stream of traffic (e.g., similar route), a change in the planned altitude profile for an aircraft, or change in the planned route for the aircraft. Flow restrictions are typically imposed to mitigate traffic congestion at an airport or in a region of airspace, particularly congestion due to inclement weather, or the unavailability of a runway or region of airspace. A delay credit would be allocated to an operator of a flight that has accepted, or upon which was imposed, a flow restriction. The amount of the credit would increase with the amount of delay caused by the flow restriction, the exact amount depending on which of several candidate formulas is eventually chosen. For example, according to one formula, there would be no credit for a delay smaller than some threshold value (e.g., 30 seconds) and the amount of the credit for a longer delay would be set at the amount of the delay minus the threshold value. Optionally, the value of a delay credit could be made to decay with time according to a suitable formula (e.g., an exponential decay). Also, optionally, a transaction charge could be assessed against the value of a delay credit that an operator used on a flight different from the one for which the delay originated or that was traded with a different operator. The delay credits accumulated by a given airline could be utilized in various ways. For example, an operator could enter a bid for priority handling in a new flow restriction that impacts one or more of the operator s flights; if the bid were unsuccessful, all or a portion of the credit would be returned to the bidder. If the bid pertained to a single aircraft that was in a queue, delay credits could be consumed in moving the aircraft to an earlier position within the queue. In the case of a flow restriction involving a choice of alternate routes, planned altitude profile, aircraft spacing, or other non-queue flow restrictions, delay credits could be used to bid for an alternative assignment.

NASA Research on an Integrated Concept for Airport Surface Operations Management

NASA Technical Reports Server (NTRS)

Gupta, Gautam

2012-01-01

Surface operations at airports in the US are based on tactical operations, where departure aircraft primarily queue up and wait at the departure runways. There have been attempts to address the resulting inefficiencies with both strategic and tactical tools for metering departure aircraft. This presentation gives an overview of Spot And Runway Departure Advisor with Collaborative Decision Making (SARDA-CDM): an integrated strategic and tactical system for improving surface operations by metering departure aircraft. SARDA-CDM is the augmentation of ground and local controller advisories through sharing of flight movement and related operations information between airport operators, flight operators and air traffic control at the airport. The goal is to enhance the efficiency of airport surface operations by exchanging information between air traffic control and airline operators, while minimizing adverse effects on stakeholders and passengers. The presentation motivates the need for departure metering, and provides a brief background on the previous work on SARDA. Then, the concept of operations for SARDA-CDM is described. Then the preliminary results from testing the concept in a real-time automated simulation environment are described. Results indicate benefits such as reduction in taxiing delay and fuel consumption. Further, the preliminary implementation of SARDA-CDM seems robust for two minutes delay in gate push-back times.

Impact of congestion on bus operations and costs.

DOT National Transportation Integrated Search

2003-10-01

Traffic congestion in Northern New Jersey imposes substantial operational and monetary penalty on bus service. The purpose of this project was to quantify the additional time and costs due to traffic congestion. A regression model was developed that ...

A Human-in-the Loop Evaluation of a Coordinated Arrival Departure Scheduling Operations for Managing Departure Delays at LaGuardia Airport

NASA Technical Reports Server (NTRS)

Lee, Paul U.; Smith, Nancy M.; Bienert, Nancy; Brasil, Connie; Buckley, Nathan; Chevalley, Eric; Homola, Jeffrey; Omar, Faisal; Parke, Bonny; Yoo, Hyo-Sang

2016-01-01

LaGuardia (LGA) departure delay was identified by the stakeholders and subject matter experts as a significant bottleneck in the New York metropolitan area. Departure delay at LGA is primarily due to dependency between LGA's arrival and departure runways: LGA departures cannot begin takeoff until arrivals have cleared the runway intersection. If one-in one-out operations are not maintained and a significant arrival-to-departure imbalance occurs, the departure backup can persist through the rest of the day. At NASA Ames Research Center, a solution called "Departure-sensitive Arrival Spacing" (DSAS) was developed to maximize the departure throughput without creating significant delays in the arrival traffic. The concept leverages a Terminal Sequencing and Spacing (TSS) operations that create and manage the arrival schedule to the runway threshold and added an interface enhancement to the traffic manager's timeline to provide the ability to manually adjust inter-arrival spacing to build precise gaps for multiple departures between arrivals. A more complete solution would include a TSS algorithm enhancement that could automatically build these multi-departure gaps. With this set of capabilities, inter-arrival spacing could be controlled for optimal departure throughput. The concept was prototyped in a human-in-the- loop (HITL) simulation environment so that operational requirements such as coordination procedures, timing and magnitude of TSS schedule adjustments, and display features for Tower, TRACON and Traffic Management Unit could be determined. A HITL simulation was conducted in August 2014 to evaluate the concept in terms of feasibility, controller workload impact, and potential benefits. Three conditions were tested, namely a Baseline condition without scheduling, TSS condition that schedules the arrivals to the runway threshold, and TSS+DSAS condition that adjusts the arrival schedule to maximize the departure throughput. The results showed that during high arrival demand period, departure throughput could be incrementally increased under TSS and TSS+DSAS conditions without compromising the arrival throughput. The concept, operational procedures, and summary results were originally published in ATM20151 but detailed results were omitted. This paper expands on the earlier paper to provide the detailed results on throughput, conformance, safety, flight time/distance, etc. that provide extra insights into the feasibility and the potential benefits on the concept.

Enhancing CORSIM for simulating high occupancy/toll lane operations.

DOT National Transportation Integrated Search

2012-03-15

Congestion pricing has been advocated as an efficient way to mitigate traffic congestion : since 1920s. A prevalent form of congestion pricing in the U.S. is high occupancy/toll (HOT) : lanes. The operating objective of HOT lanes is to improve the th...

Benefit Opportunities for Integrated Surface and Airspace Departure Scheduling: A Study of Operations at Charlotte-Douglas International Airport

NASA Technical Reports Server (NTRS)

Coppenbarger, Rich; Jung, Yoon; Kozon, Tom; Farrahi, Amir; Malik, Wakar; Lee, Hanbong; Chevalley, Eric; Kistler, Matt

2016-01-01

NASA is collaborating with the FAA and aviation industry to develop and demonstrate new capabilities that integrate arrival, departure, and surface air-traffic operations. The concept relies on trajectory-based departure scheduling and collaborative decision making to reduce delays and uncertainties in taxi and climb operations. The paper describes the concept and benefit mechanisms aimed at improving flight efficiency and predictability while maintaining or improving operational throughput. The potential impact of the technology is studied and discussed through a quantitative analysis of relevant shortfalls at the site identified for initial deployment and demonstration in 2017: Charlotte-Douglas International Airport. Results from trajectory analysis indicate substantial opportunity to reduce taxi delays for both departures and arrivals by metering departures at the gate in a manner that maximizes throughput while adhering to takeoff restrictions due mostly to airspace constraints. Substantial taxi-out delay reduction is shown for flights subject to departure restrictions stemming from traffic flow management initiatives. Opportunities to improve the predictability of taxi, takeoff, and climb operations are examined and their potential impact on airline scheduling decisions and air-traffic forecasting is discussed. In addition, the potential to improve throughput with departure scheduling that maximizes use of available runway and airspace capacity is analyzed.

49 CFR 236.587 - Departure test.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Departure test. 236.587 Section 236.587..., Train Control and Cab Signal Systems Inspection and Tests; Locomotive § 236.587 Departure test. (a) The...: (1) Operation over track elements; (2) Operation over test circuit; (3) Use of portable test...

49 CFR 236.587 - Departure test.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Departure test. 236.587 Section 236.587..., Train Control and Cab Signal Systems Inspection and Tests; Locomotive § 236.587 Departure test. (a) The...: (1) Operation over track elements; (2) Operation over test circuit; (3) Use of portable test...

Runway Operations Planning: A Two-Stage Heuristic Algorithm

NASA Technical Reports Server (NTRS)

Anagnostakis, Ioannis; Clarke, John-Paul

2003-01-01

The airport runway is a scarce resource that must be shared by different runway operations (arrivals, departures and runway crossings). Given the possible sequences of runway events, careful Runway Operations Planning (ROP) is required if runway utilization is to be maximized. From the perspective of departures, ROP solutions are aircraft departure schedules developed by optimally allocating runway time for departures given the time required for arrivals and crossings. In addition to the obvious objective of maximizing throughput, other objectives, such as guaranteeing fairness and minimizing environmental impact, can also be incorporated into the ROP solution subject to constraints introduced by Air Traffic Control (ATC) procedures. This paper introduces a two stage heuristic algorithm for solving the Runway Operations Planning (ROP) problem. In the first stage, sequences of departure class slots and runway crossings slots are generated and ranked based on departure runway throughput under stochastic conditions. In the second stage, the departure class slots are populated with specific flights from the pool of available aircraft, by solving an integer program with a Branch & Bound algorithm implementation. Preliminary results from this implementation of the two-stage algorithm on real-world traffic data are presented.

14 CFR 137.49 - Operations over other than congested areas.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Operations over other than congested areas. 137.49 Section 137.49 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... congested areas below 500 feet above the surface and closer than 500 feet to persons, vessels, vehicles, and...

30 CFR 250.409 - May I obtain departures from these drilling requirements?

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 2 2013-07-01 2013-07-01 false May I obtain departures from these drilling..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations General Requirements § 250.409 May I obtain departures from these drilling...

30 CFR 250.409 - May I obtain departures from these drilling requirements?

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 2 2014-07-01 2014-07-01 false May I obtain departures from these drilling..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations General Requirements § 250.409 May I obtain departures from these drilling...

30 CFR 250.409 - May I obtain departures from these drilling requirements?

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 2 2012-07-01 2012-07-01 false May I obtain departures from these drilling..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations General Requirements § 250.409 May I obtain departures from these drilling...

30 CFR 250.409 - May I obtain departures from these drilling requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations General Requirements § 250.409 May I obtain departures from these drilling requirements? The District... 30 Mineral Resources 2 2010-07-01 2010-07-01 false May I obtain departures from these drilling...

30 CFR 250.409 - May I obtain departures from these drilling requirements?

Code of Federal Regulations, 2011 CFR

2011-07-01

... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations General Requirements § 250.409 May I obtain departures from these... 30 Mineral Resources 2 2011-07-01 2011-07-01 false May I obtain departures from these drilling...

Making the Traffic Operations Case for Congestion Pricing: Operational Impacts of Congestion Pricing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chin, Shih-Miao; Hu, Patricia S; Davidson, Diane

2011-02-01

Congestion begins when an excess of vehicles on a segment of roadway at a given time, resulting in speeds that are significantly slower than normal or 'free flow' speeds. Congestion often means stop-and-go traffic. The transition occurs when vehicle density (the number of vehicles per mile in a lane) exceeds a critical level. Once traffic enters a state of congestion, recovery or time to return to a free-flow state is lengthy; and during the recovery process, delay continues to accumulate. The breakdown in speed and flow greatly impedes the efficient operation of the freeway system, resulting in economic, mobility, environmentalmore » and safety problems. Freeways are designed to function as access-controlled highways characterized by uninterrupted traffic flow so references to freeway performance relate primarily to the quality of traffic flow or traffic conditions as experienced by users of the freeway. The maximum flow or capacity of a freeway segment is reached while traffic is moving freely. As a result, freeways are most productive when they carry capacity flows at 60 mph, whereas lower speeds impose freeway delay, resulting in bottlenecks. Bottlenecks may be caused by physical disruptions, such as a reduced number of lanes, a change in grade, or an on-ramp with a short merge lane. This type of bottleneck occurs on a predictable or 'recurrent' basis at the same time of day and same day of week. Recurrent congestion totals 45% of congestion and is primarily from bottlenecks (40%) as well as inadequate signal timing (5%). Nonrecurring bottlenecks result from crashes, work zone disruptions, adverse weather conditions, and special events that create surges in demand and that account for over 55% of experienced congestion. Figure 1.1 shows that nonrecurring congestion is composed of traffic incidents (25%), severe weather (15%), work zones, (10%), and special events (5%). Between 1995 and 2005, the average percentage change in increased peak traveler delay, based on hours spent in traffic in a year, grew by 22% as the national average of hours spent in delay grew from 36 hours to 44 hours. Peak delay per traveler grew one-third in medium-size urban areas over the 10 year period. The traffic engineering community has developed an arsenal of integrated tools to mitigate the impacts of congestion on freeway throughput and performance, including pricing of capacity to manage demand for travel. Congestion pricing is a strategy which dynamically matches demand with available capacity. A congestion price is a user fee equal to the added cost imposed on other travelers as a result of the last traveler's entry into the highway network. The concept is based on the idea that motorists should pay for the additional congestion they create when entering a congested road. The concept calls for fees to vary according to the level of congestion with the price mechanism applied to make travelers more fully aware of the congestion externality they impose on other travelers and the system itself. The operational rationales for the institution of pricing strategies are to improve the efficiency of operations in a corridor and/or to better manage congestion. To this end, the objectives of this project were to: (1) Better understand and quantify the impacts of congestion pricing strategies on traffic operations through the study of actual projects, and (2) Better understand and quantify the impacts of congestion pricing strategies on traffic operations through the use of modeling and other analytical methods. Specifically, the project was to identify credible analytical procedures that FHWA can use to quantify the impacts of various congestion pricing strategies on traffic flow (throughput) and congestion.« less

2012 urban congestion trends, operations : the key to reliable travel.

DOT National Transportation Integrated Search

2013-04-01

Congestion levels remained relatively unchanged : from 2011 to 2012 in the 19 urban areas in the United States monitored : in this report. : Congestion levels across all of the congestion measures are still generally : below the levels experienced in...

Characterization of Tactical Departure Scheduling in the National Airspace System

NASA Technical Reports Server (NTRS)

Capps, Alan; Engelland, Shawn A.

2011-01-01

This paper discusses and analyzes current day utilization and performance of the tactical departure scheduling process in the National Airspace System (NAS) to understand the benefits in improving this process. The analysis used operational air traffic data from over 1,082,000 flights during the month of January, 2011. Specific metrics included the frequency of tactical departure scheduling, site specific variances in the technology's utilization, departure time prediction compliance used in the tactical scheduling process and the performance with which the current system can predict the airborne slot that aircraft are being scheduled into from the airport surface. Operational data analysis described in this paper indicates significant room for improvement exists in the current system primarily in the area of reduced departure time prediction uncertainty. Results indicate that a significant number of tactically scheduled aircraft did not meet their scheduled departure slot due to departure time uncertainty. In addition to missed slots, the operational data analysis identified increased controller workload associated with tactical departures which were subject to traffic management manual re-scheduling or controller swaps. An analysis of achievable levels of departure time prediction accuracy as obtained by a new integrated surface and tactical scheduling tool is provided to assess the benefit it may provide as a solution to the identified shortfalls. A list of NAS facilities which are likely to receive the greatest benefit from the integrated surface and tactical scheduling technology are provided.

Real Time Metrics and Analysis of Integrated Arrival, Departure, and Surface Operations

NASA Technical Reports Server (NTRS)

Sharma, Shivanjli; Fergus, John

2017-01-01

To address the Integrated Arrival, Departure, and Surface (IADS) challenge, NASA is developing and demonstrating trajectory-based departure automation under a collaborative effort with the FAA and industry known Airspace Technology Demonstration 2 (ATD-2). ATD-2 builds upon and integrates previous NASA research capabilities that include the Spot and Runway Departure Advisor (SARDA), the Precision Departure Release Capability (PDRC), and the Terminal Sequencing and Spacing (TSAS) capability. As trajectory-based departure scheduling and collaborative decision making tools are introduced in order to reduce delays and uncertainties in taxi and climb operations across the National Airspace System, users of the tools across a number of roles benefit from a real time system that enables common situational awareness. A real time dashboard was developed to inform and present users notifications and integrated information regarding airport surface operations. The dashboard is a supplement to capabilities and tools that incorporate arrival, departure, and surface air-traffic operations concepts in a NextGen environment. In addition to shared situational awareness, the dashboard offers the ability to compute real time metrics and analysis to inform users about capacity, predictability, and efficiency of the system as a whole. This paper describes the architecture of the real time dashboard as well as an initial proposed set of metrics. The potential impact of the real time dashboard is studied at the site identified for initial deployment and demonstration in 2017: Charlotte-Douglas International Airport (CLT). The architecture of implementing such a tool as well as potential uses are presented for operations at CLT. Metrics computed in real time illustrate the opportunity to provide common situational awareness and inform users of system delay, throughput, taxi time, and airport capacity. In addition, common awareness of delays and the impact of takeoff and departure restrictions stemming from traffic flow management initiatives are explored. The potential of the real time tool to inform users of the predictability and efficiency of using a trajectory-based departure scheduling system is also discussed.

23 CFR 450.320 - Congestion management process in transportation management areas.

Code of Federal Regulations, 2010 CFR

2010-04-01

... travel demand reduction and operational management strategies. (b) The development of a congestion... appropriate analysis of reasonable (including multimodal) travel demand reduction and operational management... the analysis demonstrates that travel demand reduction and operational management strategies cannot...

Interaction of Airspace Partitions and Traffic Flow Management Delay with Weather

NASA Technical Reports Server (NTRS)

Lee, Hak-Tae; Chatterji, Gano B.; Palopo, Kee

2011-01-01

The interaction of partitioning the airspace and delaying flights in the presence of convective weather is explored to study how re-partitioning the airspace can help reduce congestion and delay. Three approaches with varying complexities are employed to compute the ground delays.In the first approach, an airspace partition of 335 high-altitude sectors that is based on clear weather day traffic is used. Routes are then created to avoid regions of convective weather. With traffic flow management, this approach establishes the baseline with per-flight delay of 8.4 minutes. In the second approach, traffic flow management is used to select routes and assign departure delays such that only the airport capacity constraints are met. This results in 6.7 minutes of average departure delay. The airspace is then partitioned with a specific capacity. It is shown that airspace-capacity-induced delay can be reduced to zero ata cost of 20percent more sectors for the examined scenario.

14 CFR 105.21 - Parachute operations over or into a congested area or an open-air assembly of persons.

Code of Federal Regulations, 2010 CFR

2010-01-01

... congested area or an open-air assembly of persons. 105.21 Section 105.21 Aeronautics and Space FEDERAL...-air assembly of persons. (a) No person may conduct a parachute operation, and no pilot in command of... congested area of a city, town, or settlement, or an open-air assembly of persons unless a certificate of...

Spot and Runway Departure Advisor (SARDA)

NASA Technical Reports Server (NTRS)

Jung, Yoon

2016-01-01

Spot and Runway Departure Advisor (SARDA) is a decision support tool to assist airline ramp controllers and ATC tower controllers to manage traffic on the airport surface to significantly improve efficiency and predictability in surface operations. The core function of the tool is the runway scheduler which generates an optimal solution for runway sequence and schedule of departure aircraft, which would minimize system delay and maximize runway throughput. The presentation also discusses the latest status of NASA's current surface research through a collaboration with an airline partner, where a tool is developed for airline ramp operators to assist departure pushback operations. The presentation describes the concept of the SARDA tool and results from human-in-the-loop simulations conducted in 2012 for Dallas-Ft. Worth International Airport and 2014 for Charlotte airport ramp tower.

Applications of variable speed control for contending with recurrent highway congestion.

DOT National Transportation Integrated Search

2014-07-01

This research project developed vital operational guidelines for design of a variable speed limit (VSL) system and its integrated operations with ramp metering control in contending with recurrent highway congestion. The developed guidelines can serv...

Analysis of Aircraft Clusters to Measure Sector-Independent Airspace Congestion

NASA Technical Reports Server (NTRS)

Bilimoria, Karl D.; Lee, Hilda Q.

2005-01-01

The Distributed Air/Ground Traffic Management (DAG-TM) concept of operations* permits appropriately equipped aircraft to conduct Free Maneuvering operations. These independent aircraft have the freedom to optimize their trajectories in real time according to user preferences; however, they also take on the responsibility to separate themselves from other aircraft while conforming to any local Traffic Flow Management (TFM) constraints imposed by the air traffic service provider (ATSP). Examples of local-TFM constraints include temporal constraints such as a required time of arrival (RTA), as well as spatial constraints such as regions of convective weather, special use airspace, and congested airspace. Under current operations, congested airspace typically refers to a sector(s) that cannot accept additional aircraft due to controller workload limitations; hence Dynamic Density (a metric that is indicative of controller workload) can be used to quantify airspace congestion. However, for Free Maneuvering operations under DAG-TM, an additional metric is needed to quantify the airspace congestion problem from the perspective of independent aircraft. Such a metric would enable the ATSP to prevent independent aircraft from entering any local areas of congestion in which the flight deck based systems and procedures may not be able to ensure separation. This new metric, called Gaggle Density, offers the ATSP a mode of control to regulate normal operations and to ensure safety and stability during rare-normal or off-normal situations (e.g., system failures). It may be difficult to certify Free Maneuvering systems for unrestricted operations, but it may be easier to certify systems and procedures for specified levels of Gaggle Density that could be monitored by the ATSP, and maintained through relatively minor flow-rate (RTA type) restrictions. Since flight deck based separation assurance is airspace independent, the challenge is to measure congestion independent of sector boundaries. Figure 1 , reproduced from Ref. 1, depicts an example traffic situation. When the situation is analyzed by sector boundaries (left side of figure), a Dynamic Density metric would identify excessive congestion in the central sector. When the same traffic situation is analyzed independent of sector boundaries (right side of figure), a Gaggle Density metric would identify congestion in two dynamically defined areas covering portions of several sectors. The first step towards measuring airspace-independent congestion is to identify aircraft clusters, i.e., groups of closely spaced aircraft. The objective of this work is to develop techniques to detect and classify clusters of aircraft.

Acadia National Park ITS field operational test : parking report

DOT National Transportation Integrated Search

2003-04-01

An important goal of the Field Operational Test of ITS at Acadia National Park is to reduce vehicle congestion in the Park. Reduced congestion will have the added benefits of increased mobility of visitors and residents, aesthetic and environmental b...

Identifying Key Issues and Potential Solutions for Integrated Arrival, Departure, Surface Operations by Surveying Stakeholder Preferences

NASA Technical Reports Server (NTRS)

Aponso, Bimal; Coppenbarger, Richard A.; Jung, Yoon; Quon, Leighton; Lohr, Gary; O’Connor, Neil; Engelland, Shawn

2015-01-01

NASA's Aeronautics Research Mission Directorate (ARMD) collaborates with the FAA and industry to provide concepts and technologies that enhance the transition to the next-generation air-traffic management system (NextGen). To facilitate this collaboration, ARMD has a series of Airspace Technology Demonstration (ATD) sub-projects that develop, demonstrate, and transitions NASA technologies and concepts for implementation in the National Airspace System (NAS). The second of these sub-projects, ATD-2, is focused on the potential benefits to NAS stakeholders of integrated arrival, departure, surface (IADS) operations. To determine the project objectives and assess the benefits of a potential solution, NASA surveyed NAS stakeholders to understand the existing issues in arrival, departure, and surface operations, and the perceived benefits of better integrating these operations. NASA surveyed a broad cross-section of stakeholders representing the airlines, airports, air-navigation service providers, and industry providers of NAS tools. The survey indicated that improving the predictability of flight times (schedules) could improve efficiency in arrival, departure, and surface operations. Stakeholders also mentioned the need for better strategic and tactical information on traffic constraints as well as better information sharing and a coupled collaborative planning process that allows stakeholders to coordinate IADS operations. To assess the impact of a potential solution, NASA sketched an initial departure scheduling concept and assessed its viability by surveying a select group of stakeholders for a second time. The objective of the departure scheduler was to enable flights to move continuously from gate to cruise with minimal interruption in a busy metroplex airspace environment using strategic and tactical scheduling enhanced by collaborative planning between airlines and service providers. The stakeholders agreed that this departure concept could improve schedule predictability and suggested several key attributes that were necessary to make the concept successful. The goals and objectives of the planned ATD-2 sub-project will incorporate the results of this stakeholder feedback.

Simulation of automatic precision departures and missed approaches using the microwave landing system

NASA Technical Reports Server (NTRS)

Feather, J. B.

1987-01-01

Results of simulated precision departures and missed approaches using MLS guidance concepts are presented. The study was conducted under the Terminal Configured Vehicle (TCV) Program, and is an extension of previous work by DAC under the Advanced Transport Operating System (ATOPS) Technology Studies Program. The study model included simulation of an MD-80 aircraft, an autopilot, and a MLS guidance computer that provided lateral and vertical steering commands. Precision departures were evaluated using a noise abatement procedure. Several curved path departures were simulated with MLS noise and under various environmental conditions. Missed approaches were considered for the same runway, where lateral MLS guidance maintained the aircraft along the extended runway centerline. In both the departures and the missed approach cases, pitch autopilot takeoff and go-around modes of operation were used in conjunction with MLS lateral guidance.

Design and Evaluation of a Dynamic Programming Flight Routing Algorithm Using the Convective Weather Avoidance Model

NASA Technical Reports Server (NTRS)

Ng, Hok K.; Grabbe, Shon; Mukherjee, Avijit

2010-01-01

The optimization of traffic flows in congested airspace with varying convective weather is a challenging problem. One approach is to generate shortest routes between origins and destinations while meeting airspace capacity constraint in the presence of uncertainties, such as weather and airspace demand. This study focuses on development of an optimal flight path search algorithm that optimizes national airspace system throughput and efficiency in the presence of uncertainties. The algorithm is based on dynamic programming and utilizes the predicted probability that an aircraft will deviate around convective weather. It is shown that the running time of the algorithm increases linearly with the total number of links between all stages. The optimal routes minimize a combination of fuel cost and expected cost of route deviation due to convective weather. They are considered as alternatives to the set of coded departure routes which are predefined by FAA to reroute pre-departure flights around weather or air traffic constraints. A formula, which calculates predicted probability of deviation from a given flight path, is also derived. The predicted probability of deviation is calculated for all path candidates. Routes with the best probability are selected as optimal. The predicted probability of deviation serves as a computable measure of reliability in pre-departure rerouting. The algorithm can also be extended to automatically adjust its design parameters to satisfy the desired level of reliability.

Interactive orbital proximity operations planning system

NASA Technical Reports Server (NTRS)

Grunwald, Arthur J.; Ellis, Stephen R.

1990-01-01

An interactive graphical planning system for on-site planning of proximity operations in the congested multispacecraft environment about the space station is presented. The system shows the astronaut a bird's eye perspective of the space station, the orbital plane, and the co-orbiting spacecraft. The system operates in two operational modes: (1) a viewpoint mode, in which the astronaut is able to move the viewpoint around in the orbital plane to range in on areas of interest; and (2) a trajectory design mode, in which the trajectory is planned. Trajectory design involves the composition of a set of waypoints which result in a fuel-optimal trajectory which satisfies all operational constraints, such as departure and arrival constraints, plume impingement constraints, and structural constraints. The main purpose of the system is to present the trajectory and the constraints in an easily interpretable graphical format. Through a graphical interactive process, the trajectory waypoints are edited until all operational constraints are satisfied. A series of experiments was conducted to evaluate the system. Eight airline pilots with no prior background in orbital mechanics participated in the experiments. Subject training included a stand-alone training session of about 6 hours duration, in which the subjects became familiar with orbital mechanics concepts and performed a series of exercises to familiarize themselves with the control and display features of the system. They then carried out a series of production runs in which 90 different trajectory design situations were randomly addressed. The purpose of these experiments was to investigate how the planning time, planning efforts, and fuel expenditures were affected by the planning difficulty. Some results of these experiments are presented.

30 CFR 250.432 - How do I obtain a departure to diverter design and installation requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Diverter System Requirements § 250.432 How do I obtain a departure to diverter... diverter line for floating drilling operations on a dynamically positioned drillship Maintain an...

76 FR 34848 - Drawbridge Operation Regulation; Atlantic Intracoastal Waterway (AIWW), Elizabeth River, Southern...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-15

... until December 20, 2013, relieving vehicular traffic congestion during the weekday and weekend daytime... final temporary could result in additional vehicular traffic congestion without providing any additional... anticipates continued vehicular traffic congestion over the Gilmerton Highway Bridge due to the reduction of...

Development of operating mode distributions for different types of roadways under different congestion levels for vehicle emission assessment using MOVES.

PubMed

Qi, Yi; Padiath, Ameena; Zhao, Qun; Yu, Lei

2016-10-01

The Motor Vehicle Emission Simulator (MOVES) quantifies emissions as a function of vehicle modal activities. Hence, the vehicle operating mode distribution is the most vital input for running MOVES at the project level. The preparation of operating mode distributions requires significant efforts with respect to data collection and processing. This study is to develop operating mode distributions for both freeway and arterial facilities under different traffic conditions. For this purpose, in this study, we (1) collected/processed geographic information system (GIS) data, (2) developed a model of CO2 emissions and congestion from observations, (3) implemented the model to evaluate potential emission changes from a hypothetical roadway accident scenario. This study presents a framework by which practitioners can assess emission levels in the development of different strategies for traffic management and congestion mitigation. This paper prepared the primary input, that is, the operating mode ID distribution, required for running MOVES and developed models for estimating emissions for different types of roadways under different congestion levels. The results of this study will provide transportation planners or environmental analysts with the methods for qualitatively assessing the air quality impacts of different transportation operation and demand management strategies.

75 FR 69906 - Drawbridge Operation Regulation; Atlantic Intracoastal Waterway (AIWW), Elizabeth River, Southern...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-16

... opening periods for the bridge during the day, relieving vehicular traffic congestion during the weekday... the rush hour periods and on the weekends, we anticipate a decrease in vehicular traffic congestion... vehicular traffic congestion over the Gilmerton Highway Bridge due to the reduction of highway lanes and...

A Consideration of Constraints on Aircraft Departure Operations

NASA Technical Reports Server (NTRS)

Darr, Stephen T.; Morello, Samuel A.; Shay, Richard F.; Lemos, Katherine A.; Jacobsen, Robert

2009-01-01

This paper presents a system-level perspective on the operational issues and constraints that limit departure capacity at large metropolitan airports in today's air transportation system. It examines the influence of constraints evident in en route airspace, in metroplex operations, and at individual airports from today's perspective and with a view toward future gate-to-cruise operations. Cross cutting organizational and technological challenges are discussed in relation to their importance in addressing the constraints.

Real Time Metrics and Analysis of Integrated Arrival, Departure, and Surface Operations

NASA Technical Reports Server (NTRS)

Sharma, Shivanjli; Fergus, John

2017-01-01

A real time dashboard was developed in order to inform and present users notifications and integrated information regarding airport surface operations. The dashboard is a supplement to capabilities and tools that incorporate arrival, departure, and surface air-traffic operations concepts in a NextGen environment. As trajectory-based departure scheduling and collaborative decision making tools are introduced in order to reduce delays and uncertainties in taxi and climb operations across the National Airspace System, users across a number of roles benefit from a real time system that enables common situational awareness. In addition to shared situational awareness the dashboard offers the ability to compute real time metrics and analysis to inform users about capacity, predictability, and efficiency of the system as a whole. This paper describes the architecture of the real time dashboard as well as an initial set of metrics computed on operational data. The potential impact of the real time dashboard is studied at the site identified for initial deployment and demonstration in 2017; Charlotte-Douglas International Airport. Analysis and metrics computed in real time illustrate the opportunity to provide common situational awareness and inform users of metrics across delay, throughput, taxi time, and airport capacity. In addition, common awareness of delays and the impact of takeoff and departure restrictions stemming from traffic flow management initiatives are explored. The potential of the real time tool to inform the predictability and efficiency of using a trajectory-based departure scheduling system is also discussed.

Precision Departure Release Capability (PDRC) Concept of Operations

NASA Technical Reports Server (NTRS)

Engelland, Shawn; Capps, Richard A.; Day, Kevin Brian

2013-01-01

After takeoff, aircraft must merge into en route (Center) airspace traffic flows which may be subject to constraints that create localized demandcapacity imbalances. When demand exceeds capacity Traffic Management Coordinators (TMCs) often use tactical departure scheduling to manage the flow of departures into the constrained Center traffic flow. Tactical departure scheduling usually involves use of a Call for Release (CFR) procedure wherein the Tower must call the Center TMC to coordinate a release time prior to allowing the flight to depart. In present-day operations release times are computed by the Center Traffic Management Advisor (TMA) decision support tool based upon manual estimates of aircraft ready time verbally communicated from the Tower to the Center. The TMA-computed release is verbally communicated from the Center back to the Tower where it is relayed to the Local controller as a release window that is typically three minutes wide. The Local controller will manage the departure to meet the coordinated release time window. Manual ready time prediction and verbal release time coordination are labor intensive and prone to inaccuracy. Also, use of release time windows adds uncertainty to the tactical departure process. Analysis of more than one million flights from January 2011 indicates that a significant number of tactically scheduled aircraft missed their en route slot due to ready time prediction uncertainty. Uncertainty in ready time estimates may result in missed opportunities to merge into constrained en route flows and lead to lost throughput. Next Generation Air Transportation System (NextGen) plans call for development of Tower automation systems capable of computing surface trajectory-based ready time estimates. NASA has developed the Precision Departure Release Capability (PDRC) concept that uses this technology to improve tactical departure scheduling by automatically communicating surface trajectory-based ready time predictions to the Center scheduling tool. The PDRC concept also incorporates earlier NASA and FAA research into automation-assisted CFR coordination. The PDRC concept helps reduce uncertainty by automatically communicating coordinated release times with seconds-level precision enabling TMCs to work with target times rather than windows. NASA has developed a PDRC prototype system that integrates the Center's TMA system with a research prototype Tower decision support tool. A two-phase field evaluation was conducted at NASA's North Texas Research Station (NTX) in DallasFort Worth. The field evaluation validated the PDRC concept and demonstrated reduced release time uncertainty while being used for tactical departure scheduling of more than 230 operational flights over 29 weeks of operations. This paper presents the Concept of Operations. Companion papers include the Final Report and a Technology Description. ? SUBJECT:

75 FR 33666 - Parts and Accessories Necessary for Safe Operation; Applications for an Exemption From Con-Way...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-14

...), and Iteris, Inc. (Iteris) regarding the placement of lane departure warning system sensors at the top... mounting of the lane departure warning system sensors near the top of the windshield, and within the swept... departure warning system would be used to alert a driver when he or she unintentionally drifts out of their...

Precision Departure Release Capability (PDRC) Final Report

NASA Technical Reports Server (NTRS)

Engelland, Shawn A.; Capps, Richard; Day, Kevin Brian; Kistler, Matthew Stephen; Gaither, Frank; Juro, Greg

2013-01-01

After takeoff, aircraft must merge into en route (Center) airspace traffic flows that may be subject to constraints that create localized demand/capacity imbalances. When demand exceeds capacity, Traffic Management Coordinators (TMCs) and Frontline Managers (FLMs) often use tactical departure scheduling to manage the flow of departures into the constrained Center traffic flow. Tactical departure scheduling usually involves a Call for Release (CFR) procedure wherein the Tower must call the Center to coordinate a release time prior to allowing the flight to depart. In present-day operations release times are computed by the Center Traffic Management Advisor (TMA) decision support tool, based upon manual estimates of aircraft ready time verbally communicated from the Tower to the Center. The TMA-computed release time is verbally communicated from the Center back to the Tower where it is relayed to the Local controller as a release window that is typically three minutes wide. The Local controller will manage the departure to meet the coordinated release time window. Manual ready time prediction and verbal release time coordination are labor intensive and prone to inaccuracy. Also, use of release time windows adds uncertainty to the tactical departure process. Analysis of more than one million flights from January 2011 indicates that a significant number of tactically scheduled aircraft missed their en route slot due to ready time prediction uncertainty. Uncertainty in ready time estimates may result in missed opportunities to merge into constrained en route flows and lead to lost throughput. Next Generation Air Transportation System plans call for development of Tower automation systems capable of computing surface trajectory-based ready time estimates. NASA has developed the Precision Departure Release Capability (PDRC) concept that improves tactical departure scheduling by automatically communicating surface trajectory-based ready time predictions and departure runway assignments to the Center scheduling tool. The PDRC concept also incorporates earlier NASA and FAA research into automation-assisted CFR coordination. The PDRC concept reduces uncertainty by automatically communicating coordinated release times with seconds-level precision enabling TMCs and FLMs to work with target times rather than windows. NASA has developed a PDRC prototype system that integrates the Center's TMA system with a research prototype Tower decision support tool. A two-phase field evaluation was conducted at NASA's North Texas Research Station in Dallas/Fort Worth. The field evaluation validated the PDRC concept and demonstrated reduced release time uncertainty while being used for tactical departure scheduling of more than 230 operational flights over 29 weeks of operations. This paper presents research results from the PDRC research activity. Companion papers present the Concept of Operations and a Technology Description.

Guidelines for operating congested traffic signals.

DOT National Transportation Integrated Search

2010-08-01

The objective of this project was to develop guidelines for mitigating congestion in traffic signal systems. As : part of the project, researchers conducted a thorough review of literature and developed preliminary : guidelines for combating congesti...

Estimates of Potential Increases in Airport Capacity through ATC (Air Traffic Control) System Improvements in the Airport and Terminal Areas

DTIC Science & Technology

1987-10-01

departures); and (3) departures-only. A fleet mix typical of most majur airports was selected consisting of 15 percent small aircraft (e.g., Swearingen SW-4...schedules predicated on VFR operations can result in substantial delays when weather conditions force the use of IFR operations. 5.1 Difference Between

Characterizing the tradeoffs and costs associated with transportation congestion in supply chains.

DOT National Transportation Integrated Search

2010-01-21

We consider distribution and location-planning models for supply chains that explicitly : account for traffic congestion effects. The majority of facility location and transportation : planning models in the operations research literature consider fa...

Investigation of freeway operations in metro Detroit.

DOT National Transportation Integrated Search

2011-10-01

Traffic incidents are the primary cause of non-recurrent congestion in urban areas, resulting in : reductions in roadway capacity due to crashes, vehicle breakdowns, and other events. In addition to : contributing to congestion and delay, incidents c...

Traffic control strategies for congested freeways and work zones.

DOT National Transportation Integrated Search

2008-10-01

The primary objective of the research was to identify and evaluate effective ways of improving traffic operations and : safety on congested freeways. There was particular interest in finding condition-responsive traffic control solutions : for the fo...

A Concept and Implementation of Optimized Operations of Airport Surface Traffic

NASA Technical Reports Server (NTRS)

Jung, Yoon C.; Hoang, Ty; Montoya, Justin; Gupta, Gautam; Malik, Waqar; Tobias, Leonard

2010-01-01

This paper presents a new concept of optimized surface operations at busy airports to improve the efficiency of taxi operations, as well as reduce environmental impacts. The suggested system architecture consists of the integration of two decoupled optimization algorithms. The Spot Release Planner provides sequence and timing advisories to tower controllers for releasing departure aircraft into the movement area to reduce taxi delay while achieving maximum throughput. The Runway Scheduler provides take-off sequence and arrival runway crossing sequence to the controllers to maximize the runway usage. The description of a prototype implementation of this integrated decision support tool for the airport control tower controllers is also provided. The prototype decision support tool was evaluated through a human-in-the-loop experiment, where both the Spot Release Planner and Runway Scheduler provided advisories to the Ground and Local Controllers. Initial results indicate the average number of stops made by each departure aircraft in the departure runway queue was reduced by more than half when the controllers were using the advisories, which resulted in reduced taxi times in the departure queue.

Precision Departure Release Capability (PDRC) Technology Description

NASA Technical Reports Server (NTRS)

Engelland, Shawn A.; Capps, Richard; Day, Kevin; Robinson, Corissia; Null, Jody R.

2013-01-01

After takeoff, aircraft must merge into en route (Center) airspace traffic flows which may be subject to constraints that create localized demand-capacity imbalances. When demand exceeds capacity, Traffic Management Coordinators (TMCs) often use tactical departure scheduling to manage the flow of departures into the constrained Center traffic flow. Tactical departure scheduling usually involves use of a Call for Release (CFR) procedure wherein the Tower must call the Center TMC to coordinate a release time prior to allowing the flight to depart. In present-day operations release times are computed by the Center Traffic Management Advisor (TMA) decision support tool based upon manual estimates of aircraft ready time verbally communicated from the Tower to the Center. The TMA-computed release is verbally communicated from the Center back to the Tower where it is relayed to the Local controller as a release window that is typically three minutes wide. The Local controller will manage the departure to meet the coordinated release time window. Manual ready time prediction and verbal release time coordination are labor intensive and prone to inaccuracy. Also, use of release time windows adds uncertainty to the tactical departure process. Analysis of more than one million flights from January 2011 indicates that a significant number of tactically scheduled aircraft missed their en route slot due to ready time prediction uncertainty. Uncertainty in ready time estimates may result in missed opportunities to merge into constrained en route flows and lead to lost throughput. Next Generation Air Transportation System (NextGen) plans call for development of Tower automation systems capable of computing surface trajectory-based ready time estimates. NASA has developed the Precision Departure Release Capability (PDRC) concept that uses this technology to improve tactical departure scheduling by automatically communicating surface trajectory-based ready time predictions to the Center scheduling tool. The PDRC concept also incorporates earlier NASA and FAA research into automation-assisted CFR coordination. The PDRC concept helps reduce uncertainty by automatically communicating coordinated release times with seconds-level precision enabling TMCs to work with target times rather than windows. NASA has developed a PDRC prototype system that integrates the Center's TMA system with a research prototype Tower decision support tool. A two-phase field evaluation was conducted at NASA's North Texas Research Station (NTX) in Dallas-Fort Worth. The field evaluation validated the PDRC concept and demonstrated reduced release time uncertainty while being used for tactical departure scheduling of more than 230 operational flights over 29 weeks of operations. This paper presents the Technology Description. Companion papers include the Final Report and a Concept of Operations.

Assessing the value of delay to truckers and carriers.

DOT National Transportation Integrated Search

2011-07-01

This project evaluates the value of delay (VOD) to commercial vehicle operators due to highway congestion. : The VOD for congestion is a fundamental parameter driving the private sectors response to public freight : projects and policies such as c...

Assessing the value of delay to truckers and carriers.

DOT National Transportation Integrated Search

2011-07-01

This project evaluates the value of delay (VOD) to commercial vehicle operators due to highway congestion. The VOD for : congestion is a fundamental parameter driving the private sectors response to public freight projects and policies such as cor...

Congestion-Responsive On-Ramp Metering : Before and After Studies - Phase 1

DOT National Transportation Integrated Search

2016-07-06

The objective of this project was to develop recommendations toward a statewide policy of congestion responsive freeway ramp metering operation. The research is performed in two phases. In phase 1, alternative ramp metering activation strategies were...

Cruise-Efficient Short Takeoff and Landing (CESTOL): Potential Impact on Air Traffic Operations

NASA Technical Reports Server (NTRS)

Couluris, G. J.; Signor, D.; Phillips, J.

2010-01-01

The National Aeronautics and Space Administration (NASA) is investigating technological and operational concepts for introducing Cruise-Efficient Short Takeoff and Landing (CESTOL) aircraft into a future US National Airspace System (NAS) civil aviation environment. CESTOL is an aircraft design concept for future use to increase capacity and reduce emissions. CESTOL provides very flexible takeoff, climb, descent and landing performance capabilities and a high-speed cruise capability. In support of NASA, this study is a preliminary examination of the potential operational impact of CESTOL on airport and airspace capacity and delay. The study examines operational impacts at a subject site, Newark Liberty Intemational Airport (KEWR), New Jersey. The study extends these KEWR results to estimate potential impacts on NAS-wide network traffic operations due to the introduction of CESTOL at selected major airports. These are the 34 domestic airports identified in the Federal Aviation Administration's Operational Evolution Plan (OEP). The analysis process uses two fast-time simulation tools to separately model local and NAS-wide air traffic operations using predicted flight schedules for a 24-hour study period in 2016. These tools are the Sen sis AvTerminal model and NASA's Airspace Concept Evaluation System (ACES). We use both to simulate conventional-aircraft-only and CESTOL-mixed-with-conventional-aircraft operations. Both tools apply 4-dimension trajectory modeling to simulate individual flight movement. The study applies AvTerminal to model traffic operations and procedures for en route and terminal arrival and departures to and from KEWR. These AvTerminal applications model existing arrival and departure routes and profiles and runway use configurations, with the assumption jet-powered, large-sized civil CESTOL aircraft use a short runway and standard turboprop arrival and departure procedures. With these rules, the conventional jet and CESTOL aircraft are procedurally separated from each other geographically and in altitude during tenninal airspace approach and departure operations, and each use a different arrival runway. AvTeminal implements its unique Focal-point Scheduling Process to sequence, space and delay aircraft to resolve spacing and overtake conflicts among flights in the airspace and airport system serving KEWR. This Process effectively models integrated arrival and departure operations. AvTerminal assesses acceptance rates and delay magnitude and causality at selected locations, including en route outer boundary fixes, tenninal airspace arrival and departure boundary fixes, terminal airspace arrival merge and departure diverge fixes, and runway landing and takeoff runways. The analysis compares the resulting capacity impacts, flight delays and delay sources between CESTOL and conventional KEWR operations. AvTerminal quantitative results showed that CESTOL has significant capability to increase airport arrival acceptance rates (35-40% at KEWR) by taking advantage of otherwise underused airspace and runways where available. The study extrapolates the AvTerminal-derived KEWR peak arrival and departure acceptance rates to estimate capacity parameter values for each of the OEP airports in the ACES modeling of traffic through the entire NAS network. The extrapolations of acceptance rates allow full, partial or no achievement of CESTOL capacity gains at an OEP airport as determined by assessments of the degree to which local procedures allow leveraging of CESTOL capabilities. These assessments consider each OEP airport's runway geometries, runway system configurations, airport and airspace operations, and potential CESTOL traffic loadings. The ACES modeling, simulates airport and airspace spacing constraints imposed by airport runway system, terminal and en route air traffic control and traffic flow management operations using airport acceptance rates representing conventional-aircraft-only and CESTOL-mixed operations. CEOL aircraft are assumed to have Mach 0.8, and alternatively Mach 0.7, cruise speeds to examine compatibility with conventional aircraft operations in common airspace. The ACES results provides estimates of CESTOL delay impact NAS-wide and at OEP airports due to changes in OEP airport acceptance rates and changes in en route airspace potential conflict rates. Preliminary results show meaningful nationwide delay reductions (20%) due to CESTOL operations at 34 major domestic airports.

Concept of Operations for Commercial and Business Aircraft Synthetic Vision Systems. 1.0

NASA Technical Reports Server (NTRS)

Williams Daniel M.; Waller, Marvin C.; Koelling, John H.; Burdette, Daniel W.; Capron, William R.; Barry, John S.; Gifford, Richard B.; Doyle, Thomas M.

2001-01-01

A concept of operations (CONOPS) for the Commercial and Business (CaB) aircraft synthetic vision systems (SVS) is described. The CaB SVS is expected to provide increased safety and operational benefits in normal and low visibility conditions. Providing operational benefits will promote SVS implementation in the Net, improve aviation safety, and assist in meeting the national aviation safety goal. SVS will enhance safety and enable consistent gate-to-gate aircraft operations in normal and low visibility conditions. The goal for developing SVS is to support operational minima as low as Category 3b in a variety of environments. For departure and ground operations, the SVS goal is to enable operations with a runway visual range of 300 feet. The system is an integrated display concept that provides a virtual visual environment. The SVS virtual visual environment is composed of three components: an enhanced intuitive view of the flight environment, hazard and obstacle defection and display, and precision navigation guidance. The virtual visual environment will support enhanced operations procedures during all phases of flight - ground operations, departure, en route, and arrival. The applications selected for emphasis in this document include low visibility departures and arrivals including parallel runway operations, and low visibility airport surface operations. These particular applications were selected because of significant potential benefits afforded by SVS.

Quantifying incident-induced travel delays on freeways using traffic sensor data

DOT National Transportation Integrated Search

2008-02-01

Traffic congestion is a major operational problem for freeways in Washington State. Recent studies have estimated that more than 50% of freeway congestion is caused by traffic incidents. To help the Washington State Department of Transportation (WSDO...

Quantifying incident-induced travel delays on freeways using traffic sensor data

DOT National Transportation Integrated Search

2008-05-01

Traffic congestion is a major operational problem for freeways in Washington State. Recent studies have estimated that more than 50 percent of freeway congestion is caused by traffic incidents. To help the Washington State Department of Transportatio...

Charlotte - EDC Evaluation and Demonstration (CEED) Human-in-the-Loop Results Briefing to ATD-2 FAA Partners

NASA Technical Reports Server (NTRS)

Chevalley, Eric

2016-01-01

The Charlotte EDC Evaluation and Demonstration (CEED) was the first Human-In-The-Loop experiment under the Air Traffic Management Technology Demonstration-2 (ATD-2) project. The purpose of the study was fourfold: 1) to establish a simulation environment (Charlotte) for airspace operations for ATD-2 technology, 2) to simulate current-day departures and arrival operations, 3) to assess the impact of current Traffic Management Initiatives (TMI) on Charlotte (CLT) departure flows and en route operations in Washington (ZDC) and Atlanta Centers (ZTL), and 4) to assess the impact of departure takeoff time compliance on airspace operations. The experimental design compared 3 TMIs and 2 compliance levels. Fourteen FAA retired controllers participated in the simulation. In addition, two Traffic Management Coordinators from ZTL and ZDC managed traffic flows. Surface and airborne delays, control efficiency, throughput, realism, workload, and acceptability were assessed and will be compared across the experimental conditions. Participants rated the simulation as very realistic. Results indicate that different TMIs have different impacts on surface and airspace delay. Departure compliance indicates partial benefits to sector complexity and controller workload. This simulation will provide an initial assessment of the tactical scheduling problems that the ATD-2 technology will address in the near term.

Precision Departure Release Capability (PDRC): NASA to FAA Research Transition

NASA Technical Reports Server (NTRS)

Engelland, Shawn; Davis, Thomas J.

2013-01-01

After takeoff, aircraft must merge into en route (Center) airspace traffic flows which may be subject to constraints that create localized demand-capacity imbalances. When demand exceeds capacity, Traffic Management Coordinators (TMCs) and Frontline Managers (FLMs) often use tactical departure scheduling to manage the flow of departures into the constrained Center traffic flow. Tactical departure scheduling usually involves use of a Call for Release (CFR) procedure wherein the Tower must call the Center to coordinate a release time prior to allowing the flight to depart. In present-day operations release times are computed by the Center Traffic Management Advisor (TMA) decision support tool based upon manual estimates of aircraft ready time verbally communicated from the Tower to the Center. The TMA-computed release time is verbally communicated from the Center back to the Tower where it is relayed to the Local controller as a release window that is typically three minutes wide. The Local controller will manage the departure to meet the coordinated release time window. Manual ready time prediction and verbal release time coordination are labor intensive and prone to inaccuracy. Also, use of release time windows adds uncertainty to the tactical departure process. Analysis of more than one million flights from January 2011 indicates that a significant number of tactically scheduled aircraft missed their en route slot due to ready time prediction uncertainty. Uncertainty in ready time estimates may result in missed opportunities to merge into constrained en route flows and lead to lost throughput. Next Generation Air Transportation System plans call for development of Tower automation systems capable of computing surface trajectory-based ready time estimates. NASA has developed the Precision Departure Release Capability (PDRC) concept that improves tactical departure scheduling by automatically communicating surface trajectory-based ready time predictions and departure runway assignments to the Center scheduling tool. The PDRC concept also incorporates earlier NASA and FAA research into automation-assisted CFR coordination. The PDRC concept reduces uncertainty by automatically communicating coordinated release times with seconds-level precision enabling TMCs and FLMs to work with target times rather than windows. NASA has developed a PDRC prototype system that integrates the Center's TMA system with a research prototype Tower decision support tool. A two-phase field evaluation was conducted at NASA's North Texas Research Station in Dallas-Fort Worth. The field evaluation validated the PDRC concept and demonstrated reduced release time uncertainty while being used for tactical departure scheduling of more than 230 operational flights over 29 weeks of operations.

Evaluation of Pushback Decision-Support Tool Concept for Charlotte Douglas International Airport Ramp Operations

NASA Technical Reports Server (NTRS)

Hayashi, Miwa; Hoang, Ty; Jung, Yoon C.; Malik, Waqar; Lee, Hanbong; Dulchinos, Victoria L.

2015-01-01

This paper proposes a new departure pushback decision-support tool (DST) for airport ramp-tower controllers. It is based on NASA's Spot and Runway Departure Advisor (SARDA) collaborative decision-making concept, except with the modification that the gate releases now are controlled by tactical pushback (or gate-hold) advisories instead of strategic pre-assignments of target pushback times to individual departure flights. The proposed ramp DST relies on data exchange with the airport traffic control tower (ATCT) to coordinate pushbacks with the ATCT's flow-management intentions under current operational constraints, such as Traffic Management Initiative constraints. Airlines would benefit in reduced taxi delay and fuel burn. The concept was evaluated in a human-in-the-loop simulation experiment with current ramp-tower controllers at the Charlotte Douglas International Airport as participants. The results showed that the tool helped reduce taxi time by one minute per flight and overall departure flight fuel consumption by 10-12% without reducing runway throughput. Expect Departure Clearance Time (EDCT) conformance also was improved when advisories were provided. These benefits were attained without increasing the ramp-tower controllers' workload. Additionally, the advisories reduced the ATCT controllers' workload.

Scheduling and Delivering Aircraft to Departure Fixes in the NY Metroplex with Controller-Managed Spacing Tools

NASA Technical Reports Server (NTRS)

Chevalley, Eric; Parke, Bonny; Kraut, Josh M.; Bienert, Nancy; Omar, Faisal; Palmer, Everett A.

2015-01-01

In this paper, successful Time-Based Flow Management (TBFM) scheduling systems for arrivals are considered and adapted to apply to departures. We present a concept of operations that integrates Controller-Managed Spacing tools for departures (CMS-D) with existing tactical departure scheduling tools to coordinate demand at departure fixes in a metroplex environment. We tested our concept in a Human-in-the-Loop simulation and compared the effect of two scheduling conditions: 1) "Departure Scheduling" consisting of an emulation of the Integrated Departure and Arrival Capability (IDAC) where Towers and a Planner (Traffic Management Coordinator at the appropriate facility) coordinate aircraft scheduled takeoff times to departure fixes; and 2) "Arrival Sensitive Departure Scheduling" where, in addition, the Tower and Planner also consider arrival Scheduled Time of Arrivals (STAs) at the airport's dependent runway. Results indicate little difference between the two scheduling conditions, but a large difference between the No Tools and the two scheduling conditions with CMS-D tools. The scheduling/CMS-D tools conditions markedly reduced heading, speed clearances, and workload for controllers who were merging flows at the departure fixes. In the tool conditions, departure controllers conditioned departures earlier rather than later when aircraft were tied near the departure fixes. In the scheduling/CMS-D tools conditions, departures crossed the departure fixes 50 seconds earlier and with an 8% error rate (consisting of time ahead or behind desired time of arrival) compared to a 19% error rate in the No Tool condition. Two exploratory runs showed that similar beneficial effects can be obtained only with the CMS-D tools without scheduling takeoff times, but at the cost of a somewhat higher workload for controllers, indicating the benefits of pre-departure scheduling of aircraft with minimal delays. Hence, we found that CMS-D tools were very beneficial in the metroplex environment we tested but that further research is needed to clarify the benefits of the various scheduling approaches.

A Minimax Network Flow Model for Characterizing the Impact of Slot Restrictions

NASA Technical Reports Server (NTRS)

Lee, Douglas W.; Patek, Stephen D.; Alexandrov, Natalia; Bass, Ellen J.; Kincaid, Rex K.

2010-01-01

This paper proposes a model for evaluating long-term measures to reduce congestion at airports in the National Airspace System (NAS). This model is constructed with the goal of assessing the global impacts of congestion management strategies, specifically slot restrictions. We develop the Minimax Node Throughput Problem (MINNTHRU), a multicommodity network flow model that provides insight into air traffic patterns when one minimizes the worst-case operation across all airports in a given network. MINNTHRU is thus formulated as a model where congestion arises from network topology. It reflects not market-driven airline objectives, but those of a regulatory authority seeking a distribution of air traffic beneficial to all airports, in response to congestion management measures. After discussing an algorithm for solving MINNTHRU for moderate-sized (30 nodes) and larger networks, we use this model to study the impacts of slot restrictions on the operation of an entire hub-spoke airport network. For both a small example network and a medium-sized network based on 30 airports in the NAS, we use MINNTHRU to demonstrate that increasing the severity of slot restrictions increases the traffic around unconstrained hub airports as well as the worst-case level of operation over all airports.

Characterization of arterial traffic congestion through analysis of operational parameters (gap acceptance and lane changing).

DOT National Transportation Integrated Search

2010-05-01

This project monitored an urban arterial highway to characterize recurring congestion. There were two major initiatives in the project. The first one focused on observed variations in gap acceptance and lane changing in relation to traffic flow rates...

Transport Protocols for Wireless Mesh Networks

NASA Astrophysics Data System (ADS)

Eddie Law, K. L.

Transmission control protocol (TCP) provides reliable connection-oriented services between any two end systems on the Internet. With TCP congestion control algorithm, multiple TCP connections can share network and link resources simultaneously. These TCP congestion control mechanisms have been operating effectively in wired networks. However, performance of TCP connections degrades rapidly in wireless and lossy networks. To sustain the throughput performance of TCP connections in wireless networks, design modifications may be required accordingly in the TCP flow control algorithm, and potentially, in association with other protocols in other layers for proper adaptations. In this chapter, we explain the limitations of the latest TCP congestion control algorithm, and then review some popular designs for TCP connections to operate effectively in wireless mesh network infrastructure.

Interaction Between Strategic and Local Traffic Flow Controls

NASA Technical Reports Server (NTRS)

Grabbe, Son; Sridhar, Banavar; Mukherjee, Avijit; Morando, Alexander

2010-01-01

The loosely coordinated sets of traffic flow management initiatives that are operationally implemented at the national- and local-levels have the potential to under, over, and inconsistently control flights. This study is designed to explore these interactions through fast-time simulations with an emphasis on identifying inequitable situations in which flights receive multiple uncoordinated delays. Two operationally derived scenarios were considered in which flights arriving into the Dallas/Fort Worth International Airport were first controlled at the national-level, either with a Ground Delay Program or a playbook reroute. These flights were subsequently controlled at the local level. The Traffic Management Advisor assigned them arrival scheduling delays. For the Ground Delay Program scenarios, between 51% and 53% of all arrivals experience both pre-departure delays from the Ground Delay Program and arrival scheduling delays from the Traffic Management Advisor. Of the subset of flights that received multiple delays, between 5.7% and 6.4% of the internal departures were first assigned a pre-departure delay by the Ground Delay Program, followed by a second pre-departure delay as a result of the arrival scheduling. For the playbook reroute scenario, Dallas/Fort Worth International Airport arrivals were first assigned pre-departure reroutes based on the MW_2_DALLAS playbook plan, and were subsequently assigned arrival scheduling delays by the Traffic Management Advisor. Since the airport was operating well below capacity when the playbook reroute was in effect, only 7% of the arrivals were observed to receive both rerouting and arrival scheduling delays. Findings from these initial experiments confirm field observations that Ground Delay Programs operated in conjunction with arrival scheduling can result in inequitable situations in which flights receive multiple uncoordinated delays.

Scheduling and Separating Departures Crossing Arrival Flows in Shared Airspace

NASA Technical Reports Server (NTRS)

Chevalley, Eric; Parke, Bonny K.; Lee, Paul; Omar, Faisal; Lee, Hwasoo; Beinert, Nancy; Kraut, Joshua M.; Palmer, Everett

2013-01-01

Flight efficiency and reduction of flight delays are among the primary goals of NextGen. In this paper, we propose a concept of shared airspace where departures fly across arrival flows, provided gaps are available in these flows. We have explored solutions to separate departures temporally from arrival traffic and pre-arranged procedures to support controllers' decisions. We conducted a Human-in-the-Loop simulation and assessed the efficiency and safety of 96 departures from the San Jose airport (SJC) climbing across the arrival airspace of the Oakland and San Francisco arrival flows. In our simulation, the SJC tower had a tool to schedule departures to fly across predicted gaps in the arrival flow. When departures were mistimed and separation could not be ensured, a safe but less efficient route was provided to the departures to fly under the arrival flows. A coordination using a point-out procedure allowed the arrival controller to control the SJC departures right after takeoff. We manipulated the accuracy of departure time (accurate vs. inaccurate) as well as which sector took control of the departures after takeoff (departure vs. arrival sector) in a 2x2 full factorial plan. Results show that coordination time decreased and climb efficiency increased when the arrival sector controlled the aircraft right after takeoff. Also, climb efficiency increased when the departure times were more accurate. Coordination was shown to be a critical component of tactical operations in shared airspace. Although workload, coordination, and safety were judged by controllers as acceptable in the simulation, it appears that in the field, controllers would need improved tools and coordination procedures to support this procedure.

Freight distribution problems in congested urban areas : fast and effective solution procedures to time-dependent vehicle routing problems

DOT National Transportation Integrated Search

2011-01-01

Congestion is a common phenomenon in all medium to large cities of the world. Reliability of freight movement in urban areas is an important : issue to manufacturing or service companies whose operation is based in just-in-time approaches. These comp...

Comprehensive Truck Size and Weight (TS&W) Study. Phase 1-synthesis, working paper 6 : traffic operations and truck size and weight regulations

DOT National Transportation Integrated Search

2012-04-01

This report presents the Exogenous Factors Test Plan for the national evaluation of the Los Angeles County Congestion Reduction Demonstration (LAC CRD) under the United States Department of Transportation (U.S. DOT) Congestion Reduction Demonstration...

78 FR 53107 - Drawbridge Operation Regulation; Passaic River, Kearny and Newark, NJ

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-28

... reducing vehicular traffic congestion during the morning and afternoon vehicular rush hour periods due to... alleviate traffic congestion resulting from area roadway closures. It is expected that this change to the regulations would provide relief to vehicular traffic while continuing to meet the reasonable needs of...

Effect of Uncertainty on Deterministic Runway Scheduling

NASA Technical Reports Server (NTRS)

Gupta, Gautam; Malik, Waqar; Jung, Yoon C.

2012-01-01

Active runway scheduling involves scheduling departures for takeoffs and arrivals for runway crossing subject to numerous constraints. This paper evaluates the effect of uncertainty on a deterministic runway scheduler. The evaluation is done against a first-come- first-serve scheme. In particular, the sequence from a deterministic scheduler is frozen and the times adjusted to satisfy all separation criteria; this approach is tested against FCFS. The comparison is done for both system performance (throughput and system delay) and predictability, and varying levels of congestion are considered. The modeling of uncertainty is done in two ways: as equal uncertainty in availability at the runway as for all aircraft, and as increasing uncertainty for later aircraft. Results indicate that the deterministic approach consistently performs better than first-come-first-serve in both system performance and predictability.

Crew procedures for microwave landing system operations

NASA Technical Reports Server (NTRS)

Summers, Leland G.

1987-01-01

The objective of this study was to identify crew procedures involved in Microwave Landing System (MLS) operations and to obtain a preliminary assessment of crew workload. The crew procedures were identified for three different complements of airborne equipment coupled to an autopilot. Using these three equipment complements, crew tasks were identified for MLS approaches and precision departures and compared to an ILS approach and a normal departure. Workload comparisons between the approaches and departures were made by using a task-timeline analysis program that obtained workload indexes, i.e., the radio of time required to complete the tasks to the time available. The results showed an increase in workload for the MLS scenario for one of the equipment complements. However, even this workload was within the capacity of two crew members.

The cost of noise reduction for departure and arrival operations of commercial tilt rotor aircraft

NASA Technical Reports Server (NTRS)

Faulkner, H. B.; Swan, W. M.

1976-01-01

The relationship between direct operating cost (DOC) and noise annoyance due to a departure and an arrival operation was developed for commercial tilt rotor aircraft. This was accomplished by generating a series of tilt rotor aircraft designs to meet various noise goals at minimum DOC. These vehicles ranged across the spectrum of possible noise levels from completely unconstrained to the quietest vehicles that could be designed within the study ground rules. Optimization parameters were varied to find the minimum DOC. This basic variation was then extended to different aircraft sizes and technology time frames.

Benefits Assessment for Tactical Runway Configuration Management Tool

NASA Technical Reports Server (NTRS)

Oseguera-Lohr, Rosa; Phojanamongkolkij, Nipa; Lohr, Gary; Fenbert, James W.

2013-01-01

The Tactical Runway Configuration Management (TRCM) software tool was developed to provide air traffic flow managers and supervisors with recommendations for airport configuration changes and runway usage. The objective for this study is to conduct a benefits assessment at Memphis (MEM), Dallas Fort-Worth (DFW) and New York's John F. Kennedy (JFK) airports using the TRCM tool. Results from simulations using the TRCM-generated runway configuration schedule are compared with results using historical schedules. For the 12 days of data used in this analysis, the transit time (arrival fix to spot on airport movement area for arrivals, or spot to departure fix for departures) for MEM departures is greater (7%) than for arrivals (3%); for JFK, there is a benefit for arrivals (9%) but not for departures (-2%); for DFW, arrivals show a slight benefit (1%), but this is offset by departures (-2%). Departure queue length benefits show fewer aircraft in queue for JFK (29%) and MEM (11%), but not for DFW (-13%). Fuel savings for surface operations at MEM are seen for both arrivals and departures. At JFK there are fuel savings for arrivals, but these are offset by increased fuel use for departures. In this study, no surface fuel benefits resulted for DFW. Results suggest that the TRCM algorithm requires modifications for complex surface traffic operations that can cause taxi delays. For all three airports, the average number of changes in flow direction (runway configuration) recommended by TRCM was many times greater than the historical data; TRCM would need to be adapted to a particular airport's needs, to limit the number of changes to acceptable levels. The results from this analysis indicate the TRCM tool can provide benefits at some high-capacity airports. The magnitude of these benefits depends on many airport-specific factors and would require adaptation of the TRCM tool; a detailed assessment is needed prior to determining suitability for a particular airport.

Trajectory-Based Takeoff Time Predictions Applied to Tactical Departure Scheduling: Concept Description, System Design, and Initial Observations

NASA Technical Reports Server (NTRS)

Engelland, Shawn A.; Capps, Alan

2011-01-01

Current aircraft departure release times are based on manual estimates of aircraft takeoff times. Uncertainty in takeoff time estimates may result in missed opportunities to merge into constrained en route streams and lead to lost throughput. However, technology exists to improve takeoff time estimates by using the aircraft surface trajectory predictions that enable air traffic control tower (ATCT) decision support tools. NASA s Precision Departure Release Capability (PDRC) is designed to use automated surface trajectory-based takeoff time estimates to improve en route tactical departure scheduling. This is accomplished by integrating an ATCT decision support tool with an en route tactical departure scheduling decision support tool. The PDRC concept and prototype software have been developed, and an initial test was completed at air traffic control facilities in Dallas/Fort Worth. This paper describes the PDRC operational concept, system design, and initial observations.

How Travel Demand Affects Detection of Non-Recurrent Traffic Congestion on Urban Road Networks

NASA Astrophysics Data System (ADS)

Anbaroglu, B.; Heydecker, B.; Cheng, T.

2016-06-01

Occurrence of non-recurrent traffic congestion hinders the economic activity of a city, as travellers could miss appointments or be late for work or important meetings. Similarly, for shippers, unexpected delays may disrupt just-in-time delivery and manufacturing processes, which could lose them payment. Consequently, research on non-recurrent congestion detection on urban road networks has recently gained attention. By analysing large amounts of traffic data collected on a daily basis, traffic operation centres can improve their methods to detect non-recurrent congestion rapidly and then revise their existing plans to mitigate its effects. Space-time clusters of high link journey time estimates correspond to non-recurrent congestion events. Existing research, however, has not considered the effect of travel demand on the effectiveness of non-recurrent congestion detection methods. Therefore, this paper investigates how travel demand affects detection of non-recurrent traffic congestion detection on urban road networks. Travel demand has been classified into three categories as low, normal and high. The experiments are carried out on London's urban road network, and the results demonstrate the necessity to adjust the relative importance of the component evaluation criteria depending on the travel demand level.

The Mission Accessibility of Near-Earth Asteroids

NASA Technical Reports Server (NTRS)

Barbee, Brent W.; Abell, Paul A.; Adamo, Daniel R.; Mazanek, Daniel D.; Johnson, Lindley N.; Yeomans, Donald K.; Chodas, Paul W.; Chamberlin, Alan B.; Benner, Lance A. M.; Taylor, Patrick;

77 FR 16928 - Drawbridge Operation Regulation; Miami River, Miami, FL

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-23

... necessary to determine whether possible vehicle traffic congestion during Miami Marlins home baseball games... closed to navigation for a short period prior to the start of Miami Marlins home baseball games. Tugs and... baseball games poses a safety concern and whether a brief closure will mitigate such congestion. This 90...

75 FR 9521 - Drawbridge Operation Regulations; Elizabeth River, Eastern Branch, VA

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-03

... vehicular back-ups, delays, and congestion. During this test deviation, VDOT will gather data from the... patterns in hope of reducing roadway congestion on the bridge and local commuting area by adjusting bridge... evacuation highway in the event of emergencies. The monthly vehicular traffic counts submitted by VDOT for...

77 FR 10960 - Drawbridge Operation Regulation; Snake Creek, Islamorada, FL

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-24

... to the high volume of vehicle traffic anticipated during the Annual Nautical Flea Market, which will... vehicle traffic. Opening this bridge on demand in past years during the event has resulted in significant vehicle congestion. By opening the bridge only on the top of the hour vehicular congestion will be reduced...

Reducing transit bus emissions: Alternative fuels or traffic operations?

NASA Astrophysics Data System (ADS)

Alam, Ahsan; Hatzopoulou, Marianne

2014-06-01

In this study, we simulated the operations and greenhouse gas (GHG) emissions of transit buses along a busy corridor and quantified the effects of two different fuels (conventional diesel and compressed natural gas) as well as a set of driving conditions on emissions. Results indicate that compressed natural gas (CNG) reduces GHG emissions by 8-12% compared to conventional diesel, this reduction could increase to 16% with high levels of traffic congestion. However, the benefits of switching from conventional diesel to CNG are less apparent when the road network is uncongested. We also investigated the effects of bus operations on emissions by applying several strategies such as transit signal priority (TSP), queue jumper lanes, and relocation of bus stops. Results show that in congested conditions, TSP alone can reduce GHG emissions by 14% and when combined with improved technology; a reduction of 23% is achieved. The reduction benefits are even more apparent when other transit operational improvements are combined with TSP. Finally a sensitivity analysis was performed to investigate the effect of operational improvements on emissions under varying levels of network congestion. We observe that under “extreme congestion”, the benefits of TSP decrease.

78 FR 70396 - Parts and Accessories Necessary for Safe Operation; Renewal of Exemption for Con-Way Freight, TK...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-25

... sensors lower in the windshield of a commercial motor vehicle (CMV) than is currently permitted by the... departure warning system sensors on 1,272 of its newly purchased power units. Takata and Iteris submitted nearly identical exemption applications for their lane departure warning system sensors on December 15...

Measures to increase airfield capacity by changing aircraft runway occupancy characteristics

NASA Technical Reports Server (NTRS)

Gosling, G. D.; Kanafani, A.; Rockaday, S. L. M.

1981-01-01

Airfield capacity and aircraft runway occupancy characteristics were studied. Factors that caused runway congestion and airfield crowding were identified. Several innovations designed to alleviate the congestion are discussed. Integrated landing management, the concept that the operation of the final approach and runway should be considered in concert, was identified as underlying all of the innovations.

77 FR 790 - FirstEnergy Solutions Corp., Allegheny Energy Supply Company, LLC v. PJM Interconnection, L.L.C...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-06

... eliminate the references to the real-time market in the calculation of congestion charges that FTR holders receive and direct the Respondent to allocate incremental real-time transmission congestion charges to all... of The Respondent's Open Access Transmission Tariff and Operating Agreement (OA), as related to the...

Functional Analysis for an Integrated Capability of Arrival/Departure/Surface Management with Tactical Runway Management

NASA Technical Reports Server (NTRS)

Phojanamongkolkij, Nipa; Okuniek, Nikolai; Lohr, Gary W.; Schaper, Meilin; Christoffels, Lothar; Latorella, Kara A.

2014-01-01

The runway is a critical resource of any air transport system. It is used for arrivals, departures, and for taxiing aircraft and is universally acknowledged as a constraining factor to capacity for both surface and airspace operations. It follows that investigation of the effective use of runways, both in terms of selection and assignment as well as the timing and sequencing of the traffic is paramount to the efficient traffic flows. Both the German Aerospace Center (DLR) and NASA have developed concepts and tools to improve atomic aspects of coordinated arrival/departure/surface management operations and runway configuration management. In December 2012, NASA entered into a Collaborative Agreement with DLR. Four collaborative work areas were identified, one of which is called "Runway Management." As part of collaborative research in the "Runway Management" area, which is conducted with the DLR Institute of Flight Guidance, located in Braunschweig, the goal is to develop an integrated system comprised of the three DLR tools - arrival, departure, and surface management (collectively referred to as A/D/S-MAN) - and NASA's tactical runway configuration management (TRCM) tool. To achieve this goal, it is critical to prepare a concept of operations (ConOps) detailing how the NASA runway management and DLR arrival, departure, and surface management tools will function together to the benefit of each. To assist with the preparation of the ConOps, the integrated NASA and DLR tools are assessed through a functional analysis method described in this report. The report first provides the highlevel operational environments for air traffic management (ATM) in Germany and in the U.S., and the descriptions of the DLR's A/D/S-MAN and NASA's TRCM tools at the level of details necessary to compliment the purpose of the study. Functional analyses of each tool and a completed functional analysis of an integrated system design are presented next in the report. Future efforts to fully develop the ConOps will include: developing scenarios to fully test environmental, procedural, and data availability assumptions; executing the analysis by a walk-through of the integrated system using these scenarios; defining the appropriate role of operators in terms of their monitoring requirements and decision authority; executing the analysis by a walk-through of the integrated system with operator involvement; characterizing the environmental, system data requirements, and operator role assumptions for the ConOps.

The Agreement between Auscultation and Lung Ultrasound in Hemodialysis Patients: The LUST Study.

PubMed

Torino, Claudia; Gargani, Luna; Sicari, Rosa; Letachowicz, Krzysztof; Ekart, Robert; Fliser, Danilo; Covic, Adrian; Siamopoulos, Kostas; Stavroulopoulos, Aristeidis; Massy, Ziad A; Fiaccadori, Enrico; Caiazza, Alberto; Bachelet, Thomas; Slotki, Itzchak; Martinez-Castelao, Alberto; Coudert-Krier, Marie-Jeanne; Rossignol, Patrick; Gueler, Faikah; Hannedouche, Thierry; Panichi, Vincenzo; Wiecek, Andrzej; Pontoriero, Giuseppe; Sarafidis, Pantelis; Klinger, Marian; Hojs, Radovan; Seiler-Mussler, Sarah; Lizzi, Fabio; Siriopol, Dimitrie; Balafa, Olga; Shavit, Linda; Tripepi, Rocco; Mallamaci, Francesca; Tripepi, Giovanni; Picano, Eugenio; London, Gérard Michel; Zoccali, Carmine

2016-11-07

Accumulation of fluid in the lung is the most concerning sequela of volume expansion in patients with ESRD. Lung auscultation is recommended to detect and monitor pulmonary congestion, but its reliability in ESRD is unknown. In a subproject of the ongoing Lung Water by Ultra-Sound Guided Treatment to Prevent Death and Cardiovascular Complications in High Risk ESRD Patients with Cardiomyopathy Trial, we compared a lung ultrasound-guided ultrafiltration prescription policy versus standard care in high-risk patients on hemodialysis. The reliability of peripheral edema was tested as well. This study was on the basis of 1106 pre- and postdialysis lung ultrasound studies (in 79 patients) simultaneous with standardized lung auscultation (crackles at the lung bases) and quantification of peripheral edema. Lung congestion by crackles, edema, or a combination thereof poorly reflected the severity of congestion as detected by ultrasound B lines in various analyses, including standard regression analysis weighting for repeated measures in individual patients (shared variance of 12% and 4% for crackles and edema, respectively) and κ-statistics (κ ranging from 0.00 to 0.16). In general, auscultation had very low discriminatory power for the diagnosis of mild (area under the receiver operating curve =0.61), moderate (area under the receiver operating curve =0.65), and severe (area under the receiver operating curve =0.68) lung congestion, and the same was true for peripheral edema (receiver operating curve =0.56 or lower) and the combination of the two physical signs. Lung crackles, either alone or combined with peripheral edema, very poorly reflect interstitial lung edema in patients with ESRD. These findings reinforce the rationale underlying the Lung Water by Ultra-Sound Guided Treatment to Prevent Death and Cardiovascular Complications in High Risk ESRD Patients with Cardiomyopathy Trial, a trial adopting ultrasound B lines as an instrument to guide interventions aimed at mitigating lung congestion in high-risk patients on hemodialysis. Copyright © 2016 by the American Society of Nephrology.

The Agreement between Auscultation and Lung Ultrasound in Hemodialysis Patients: The LUST Study

PubMed Central

Torino, Claudia; Gargani, Luna; Sicari, Rosa; Letachowicz, Krzysztof; Ekart, Robert; Fliser, Danilo; Covic, Adrian; Siamopoulos, Kostas; Stavroulopoulos, Aristeidis; Massy, Ziad A.; Fiaccadori, Enrico; Caiazza, Alberto; Bachelet, Thomas; Slotki, Itzchak; Martinez-Castelao, Alberto; Coudert-Krier, Marie-Jeanne; Rossignol, Patrick; Gueler, Faikah; Hannedouche, Thierry; Panichi, Vincenzo; Wiecek, Andrzej; Pontoriero, Giuseppe; Sarafidis, Pantelis; Klinger, Marian; Hojs, Radovan; Seiler-Mussler, Sarah; Lizzi, Fabio; Siriopol, Dimitrie; Balafa, Olga; Shavit, Linda; Tripepi, Rocco; Mallamaci, Francesca; Tripepi, Giovanni; Picano, Eugenio; London, Gérard Michel

2016-01-01

Background and objectives Accumulation of fluid in the lung is the most concerning sequela of volume expansion in patients with ESRD. Lung auscultation is recommended to detect and monitor pulmonary congestion, but its reliability in ESRD is unknown. Design, setting, participants, & measurements In a subproject of the ongoing Lung Water by Ultra-Sound Guided Treatment to Prevent Death and Cardiovascular Complications in High Risk ESRD Patients with Cardiomyopathy Trial, we compared a lung ultrasound–guided ultrafiltration prescription policy versus standard care in high-risk patients on hemodialysis. The reliability of peripheral edema was tested as well. This study was on the basis of 1106 pre– and postdialysis lung ultrasound studies (in 79 patients) simultaneous with standardized lung auscultation (crackles at the lung bases) and quantification of peripheral edema. Results Lung congestion by crackles, edema, or a combination thereof poorly reflected the severity of congestion as detected by ultrasound B lines in various analyses, including standard regression analysis weighting for repeated measures in individual patients (shared variance of 12% and 4% for crackles and edema, respectively) and κ-statistics (κ ranging from 0.00 to 0.16). In general, auscultation had very low discriminatory power for the diagnosis of mild (area under the receiver operating curve =0.61), moderate (area under the receiver operating curve =0.65), and severe (area under the receiver operating curve =0.68) lung congestion, and the same was true for peripheral edema (receiver operating curve =0.56 or lower) and the combination of the two physical signs. Conclusions Lung crackles, either alone or combined with peripheral edema, very poorly reflect interstitial lung edema in patients with ESRD. These findings reinforce the rationale underlying the Lung Water by Ultra-Sound Guided Treatment to Prevent Death and Cardiovascular Complications in High Risk ESRD Patients with Cardiomyopathy Trial, a trial adopting ultrasound B lines as an instrument to guide interventions aimed at mitigating lung congestion in high-risk patients on hemodialysis. PMID:27660305

Operational Evaluatioin of Dynamic Weather Routes at American Airlines

NASA Technical Reports Server (NTRS)

McNally, David; Sheth, Kapil; Gong, Chester; Borchers, Paul; Osborne, Jeff; Keany, Desmond; Scott, Brennan; Smith, Steve; Sahlman, Scott; Lee, Chuhan;

Office of Operations R&D

DOT National Transportation Integrated Search

2013-04-30

The Office of Operations Research and Development (R&D) produces technology and tools to improve transportation system productivity, efficiency, and performance by proactively anticipating congestion and managing traffic.

Pathological and behavioral manifestations of the “Cayuga syndrome,” a thiamine deficiency in larval landlocked Atlantic salmon

USGS Publications Warehouse

Fisher, Jeffrey P.; Spitsbergen, Jan M.; Iamonte, Tina; Little, Edward E.; DeLonay, Aaron

1995-01-01

The “Cayuga syndrome” is a maternally transmitted, naturally occurring thiamine deficiency that causes 100% mortality of larval landlocked Atlantic salmon Salmo salar in several of New York's Finger Lakes, Results of multiyear studies to qualify and quantify the neurobehavioral and gross pathological signs of this condition are described, Affected sac fry became weak and ataxic and responded atypically to stimuli 1–2 weeks before death. Quantitative assays of stimulus-provoked swimming revealed a significant neuropathy whereby the sac fry exhibited abnormal thigmotactic and phototactic behaviors. Gross lesions observed in Cayuga sac fry included yolk-sac opacities, subcutaneous edema, vitelline hemorrhage or congestion, pericardial edema, retrobulbar edema, branchial congestion, foreshortened maxillae, hydrocephalus, and occasional caudal fin deformities, Lesion frequency in progeny differed significantly between dam source. Yolk conversion efficiency was decreased at least 1 week before death, suggesting that the bioenergetics of the fish was compromised and thereby supporting the thiamine residue and treatment data reported elsewhere, Comparisons with coagulated-yolk, blue-sac and swim-up syndromes are presented, The pathological signs of the Cayuga syndrome represent a unique departure from the lesions induced by toxicants or pathogens in other piscine models, and for the first time profile the profound effects of thiamine deficiency on cardiovascular and neurological systems of larval fish.

76 FR 71619 - Parts and Accessories Necessary for Safe Operation; Grant of Temporary Exemption for Con-way...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-18

..., Inc. (Takata), and Iteris, Inc. (Iteris) to mount lane departure warning system sensors lower in the... allow it to install lane departure warning system sensors on 1,272 of its newly purchased power units... system sensors on December 15, 2009 and on February 25, 2010, respectively. On June 14, 2010, FMCSA...

SARDA - Technologies for NextGen

NASA Image and Video Library

2015-04-22

The Spot and Runway Departure Advisor, or SARDA, is NASA's contribution to improving the efficiency of airport surface operations. SARDA is comprised of software-based decision support tools for controllers in the FAA tower and in the airline ramp towers. It uses intelligent schedulers to provide surface management capabilities, including departure metering and advisories for individual aircraft movement at various locations on the airport surface.

A Terminal Area Analysis of Continuous Ascent Departure Fuel Use at Dallas/Fort Worth International Airport

NASA Technical Reports Server (NTRS)

Roach, Keenan; Robinson, John E., III

2010-01-01

Aircraft departing from the Dallas/Fort Worth International Airport (DFW) encounter vertical restrictions that prevent continuous ascent operations. The result of these restrictions are temporary level-offs at 10,000 feet. A combination of flow direction, specific Area Navigation (RNAV) route geometry, and arrival streams have been found to be the biggest factors in the duration and frequency of a temporary level-offs. In total, 20% of DFW departures are affected by these level-offs, which have an average duration of just over 100 seconds. The use of continuous descent approaches at DFW are shown to lessen the impact arrivals have on the departures and allow more continuous ascents. The fuel used in a continuous ascent and an ascent with a temporary level-off have been calculated using a fuel burn rate model created from a combination of actual aircraft track data, aircraft manufacturer flight operations manuals, and Eurocontrol's Base of Aircraft Data (BADA) simulation tool. This model represents the average aggregate burn rates for the current fleet mix at DFW. Continuous ascents would save approximately seven gallons of fuel out of 450 gallons used to climb to a cruise altitude of 31,000ft per departure.

A bi-objective integer programming model for partly-restricted flight departure scheduling

PubMed Central

Guan, Wei; Zhang, Wenyi; Jiang, Shixiong; Fan, Lingling

2018-01-01

The normal studies on air traffic departure scheduling problem (DSP) mainly deal with an independent airport in which the departure traffic is not affected by surrounded airports, which, however, is not a consistent case. In reality, there still exist cases where several commercial airports are closely located and one of them possesses a higher priority. During the peak hours, the departure activities of the lower-priority airports are usually required to give way to those of higher-priority airport. These giving-way requirements can inflict a set of changes on the modeling of departure scheduling problem with respect to the lower-priority airports. To the best of our knowledge, studies on DSP under this condition are scarce. Accordingly, this paper develops a bi-objective integer programming model to address the flight departure scheduling of the partly-restricted (e.g., lower-priority) one among several adjacent airports. An adapted tabu search algorithm is designed to solve the current problem. It is demonstrated from the case study of Tianjin Binhai International Airport in China that the proposed method can obviously improve the operation efficiency, while still realizing superior equity and regularity among restricted flows. PMID:29715299

A bi-objective integer programming model for partly-restricted flight departure scheduling.

PubMed

Zhong, Han; Guan, Wei; Zhang, Wenyi; Jiang, Shixiong; Fan, Lingling

2018-01-01

The normal studies on air traffic departure scheduling problem (DSP) mainly deal with an independent airport in which the departure traffic is not affected by surrounded airports, which, however, is not a consistent case. In reality, there still exist cases where several commercial airports are closely located and one of them possesses a higher priority. During the peak hours, the departure activities of the lower-priority airports are usually required to give way to those of higher-priority airport. These giving-way requirements can inflict a set of changes on the modeling of departure scheduling problem with respect to the lower-priority airports. To the best of our knowledge, studies on DSP under this condition are scarce. Accordingly, this paper develops a bi-objective integer programming model to address the flight departure scheduling of the partly-restricted (e.g., lower-priority) one among several adjacent airports. An adapted tabu search algorithm is designed to solve the current problem. It is demonstrated from the case study of Tianjin Binhai International Airport in China that the proposed method can obviously improve the operation efficiency, while still realizing superior equity and regularity among restricted flows.

Optimal Wind Energy Integration in Large-Scale Electric Grids

NASA Astrophysics Data System (ADS)

Albaijat, Mohammad H.

The major concern in electric grid operation is operating under the most economical and reliable fashion to ensure affordability and continuity of electricity supply. This dissertation investigates the effects of such challenges, which affect electric grid reliability and economic operations. These challenges are: 1. Congestion of transmission lines, 2. Transmission lines expansion, 3. Large-scale wind energy integration, and 4. Phaser Measurement Units (PMUs) optimal placement for highest electric grid observability. Performing congestion analysis aids in evaluating the required increase of transmission line capacity in electric grids. However, it is necessary to evaluate expansion of transmission line capacity on methods to ensure optimal electric grid operation. Therefore, the expansion of transmission line capacity must enable grid operators to provide low-cost electricity while maintaining reliable operation of the electric grid. Because congestion affects the reliability of delivering power and increases its cost, the congestion analysis in electric grid networks is an important subject. Consequently, next-generation electric grids require novel methodologies for studying and managing congestion in electric grids. We suggest a novel method of long-term congestion management in large-scale electric grids. Owing to the complication and size of transmission line systems and the competitive nature of current grid operation, it is important for electric grid operators to determine how many transmission lines capacity to add. Traditional questions requiring answers are "Where" to add, "How much of transmission line capacity" to add, and "Which voltage level". Because of electric grid deregulation, transmission lines expansion is more complicated as it is now open to investors, whose main interest is to generate revenue, to build new transmission lines. Adding a new transmission capacity will help the system to relieve the transmission system congestion, create profit for investors for renting their transmission capacity, and cheaper electricity for end users. We propose a hybrid method based on a heuristic and deterministic method to attain new transmission lines additions and increase transmission capacity. Renewable energy resources (RES) have zero operating cost, which makes them very attractive for generation companies and market participants. In addition, RES have zero carbon emission, which helps relieve the concerns of environmental impacts of electric generation resources' carbon emission. RES are wind, solar, hydro, biomass, and geothermal. By 2030, the expectation is that more than 30% of electricity in the U.S. will come from RES. One major contributor of RES generation will be from wind energy resources (WES). Furthermore, WES will be an important component of the future generation portfolio. However, the nature of WES is that it experiences a high intermittency and volatility. Because of the great expectation of high WES penetration and the nature of such resources, researchers focus on studying the effects of such resources on the electric grid operation and its adequacy from different aspects. Additionally, current market operations of electric grids add another complication to consider while integrating RES (e.g., specifically WES). Mandates by market rules and long-term analysis of renewable penetration in large-scale electric grid are also the focus of researchers in recent years. We advocate a method for high-wind resources penetration study on large-scale electric grid operations. PMU is a geographical positioning system (GPS) based device, which provides immediate and precise measurements of voltage angle in a high-voltage transmission system. PMUs can update the status of a transmission line and related measurements (e.g., voltage magnitude and voltage phase angle) more frequently. Every second, a PMU can provide 30 samples of measurements compared to traditional systems (e.g., supervisory control and data acquisition [SCADA] system), which provides one sample of measurement every 2 to 5 seconds. Because PMUs provide more measurement data samples, PMU can improve electric grid reliability and observability. (Abstract shortened by UMI.)

14 CFR 65.37 - Skill requirements: Operating positions.

Code of Federal Regulations, 2011 CFR

2011-01-01

..., prescribed instrument approach, and departure procedures. (9) Radar alignment and technical operation. (10) The application of the prescribed radar and nonradar separation standard, as appropriate. [Doc. No...

14 CFR 65.37 - Skill requirements: Operating positions.

Code of Federal Regulations, 2010 CFR

2010-01-01

..., prescribed instrument approach, and departure procedures. (9) Radar alignment and technical operation. (10) The application of the prescribed radar and nonradar separation standard, as appropriate. [Doc. No...

14 CFR 65.37 - Skill requirements: Operating positions.

Code of Federal Regulations, 2014 CFR

2014-01-01

..., prescribed instrument approach, and departure procedures. (9) Radar alignment and technical operation. (10) The application of the prescribed radar and nonradar separation standard, as appropriate. [Doc. No...

14 CFR 65.37 - Skill requirements: Operating positions.

Code of Federal Regulations, 2012 CFR

2012-01-01

..., prescribed instrument approach, and departure procedures. (9) Radar alignment and technical operation. (10) The application of the prescribed radar and nonradar separation standard, as appropriate. [Doc. No...

14 CFR 65.37 - Skill requirements: Operating positions.

Code of Federal Regulations, 2013 CFR

2013-01-01

..., prescribed instrument approach, and departure procedures. (9) Radar alignment and technical operation. (10) The application of the prescribed radar and nonradar separation standard, as appropriate. [Doc. No...

Next Generation CTAS Tools

NASA Technical Reports Server (NTRS)

Erzberger, Heinz

2000-01-01

The FAA's Free Flight Phase 1 Office is in the process of deploying the current generation of CTAS tools, which are the Traffic Management Advisor (TMA) and the passive Final Approach Spacing Tool (pFAST), at selected centers and airports. Research at NASA is now focussed on extending the CTAS software and computer human interfaces to provide more advanced capabilities. The Multi-center TMA (McTMA) is designed to operate at airports where arrival flows originate from two or more centers whose boundaries are in close proximity to the TRACON boundary. McTMA will also include techniques for routing arrival flows away from congested airspace and around airspace reserved for arrivals into other hub airports. NASA is working with FAA and MITRE to build a prototype McTMA for the Philadelphia airport. The active Final Approach Spacing Tool (aFAST) provides speed and heading advisories to help controllers achieve accurate spacing between aircraft on final approach. These advisories will be integrated with those in the existing pFAST to provide a set of comprehensive advisories for controlling arrival traffic from the TRACON boundary to touchdown at complex, high-capacity airports. A research prototype of aFAST, designed for the Dallas-Fort Worth is in an advanced stage of development. The Expedite Departure Path (EDP) and Direct-To tools are designed to help controllers guide departing aircraft out of the TRACON airspace and to climb to cruise altitude along the most efficient routes.

78 FR 32088 - Standard Instrument Approach Procedures, and Takeoff Minimums and Obstacle Departure Procedures...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-29

...This rule establishes, amends, suspends, or revokes Standard Instrument Approach Procedures (SIAPs) and associated Takeoff Minimums and Obstacle Departure Procedures for operations at certain airports. These regulatory actions are needed because of the adoption of new or revised criteria, or because of changes occurring in the National Airspace System, such as the commissioning of new navigational facilities, adding new obstacles, or changing air traffic requirements. These changes are designed to provide safe and efficient use of the navigable airspace and to promote safe flight operations under instrument flight rules at the affected airports.

75 FR 69331 - Standard Instrument Approach Procedures, and Takeoff Minimums and Obstacle Departure Procedures...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-12

...This establishes, amends, suspends, or revokes Standard Instrument Approach Procedures (SIAPs) and associated Takeoff Minimums and Obstacle Departure Procedures for operations at certain airports. These regulatory actions are needed because of the adoption of new or revised criteria, or because of changes occurring in the National Airspace System, such as the commissioning of new navigational facilities, adding new obstacles, or changing air traffic requirements. These changes are designed to provide safe and efficient use of the navigable airspace and to promote safe flight operations under instrument flight rules at the affected airports.

77 FR 12454 - Standard Instrument Approach Procedures, and Takeoff Minimums and Obstacle Departure Procedures...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-01

...This rule establishes, amends, suspends, or revokes Standard Instrument Approach Procedures (SIAPs) and associated Takeoff Minimums and Obstacle Departure Procedures for operations at certain airports. These regulatory actions are needed because of the adoption of new or revised criteria, or because of changes occurring in the National Airspace System, such as the commissioning of new navigational facilities, adding new obstacles, or changing air traffic requirements. These changes are designed to provide safe and efficient use of the navigable airspace and to promote safe flight operations under instrument flight rules at the affected airports.

Benefit Assessment of the Precision Departure Release Capability Concept

NASA Technical Reports Server (NTRS)

Palopo, Kee; Chatterji, Gano B.; Lee, Hak-Tae

2011-01-01

A Precision Departure Release Capability concept is being evaluated by both the National Aeronautics and Space Administration and the Federal Aviation Administration as part of a larger goal of improving throughput, efficiency and capacity in integrated departure, arrival and surface operations. The concept is believed to have the potential of increasing flight efficiency and throughput by avoiding missing assigned slots and minimizing speed increase or path stretch to recover the slot. The main thrust of the paper is determining the impact of early and late departures from the departure runway when an aircraft has a slot assigned either at a meter fix or at the arrival airport. Results reported in the paper are for two scenarios. The first scenario considers flights out of Dallas/Fort Worth destined for Hartsfield-Jackson International Airport in Atlanta flying through the Meridian meter-fix in the Memphis Center with miles-in-trail constraints. The second scenario considers flights destined to George Bush Intercontinental/Houston Airport with specified airport arrival rate constraint. Results show that delay reduction can be achieved by allowing reasonable speed changes in scheduling. It was determined that the traffic volume between Dallas/Fort Worth and Atlanta via the Meridian fix is low and the departures times are spread enough that large departure schedule uncertainty can be tolerated. Flights can depart early or late within 90 minutes without accruing much more delay due to miles-in-trail constraint at the Meridian fix. In the Houston scenario, 808 arrivals from 174 airports were considered. Results show that delay experienced by the 16 Dallas/Fort Worth departures is higher if initial schedules of the remaining 792 flights are kept unaltered while they are rescheduled. Analysis shows that the probability of getting the initially assigned slot back after perturbation and rescheduling decreases with increasing standard deviation of the departure delay distributions. Results show that most Houston arrivals can be expected to be on time based on the assumed zero-mean Normal departure delay distributions achievable by Precision Departure Release Capability. In the current system, airport-departure delay, which is the sum of gate-departure delay and taxi-out delay, is observed at the airports. This delay acts as a bias, which can be reduced by Precision Departure Release Capability.

A System Dynamics Approach to Modeling the Sensitivity of Inappropriate Emergency Department Utilization

NASA Astrophysics Data System (ADS)

Behr, Joshua G.; Diaz, Rafael

Non-urgent Emergency Department utilization has been attributed with increasing congestion in the flow and treatment of patients and, by extension, conditions the quality of care and profitability of the Emergency Department. Interventions designed to divert populations to more appropriate care may be cautiously received by operations managers due to uncertainty about the impact an adopted intervention may have on the two values of congestion and profitability. System Dynamics (SD) modeling and simulation may be used to measure the sensitivity of these two, often-competing, values of congestion and profitability and, thus, provide an additional layer of information designed to inform strategic decision making.

Optimal Congestion Management in Electricity Market Using Particle Swarm Optimization with Time Varying Acceleration Coefficients

NASA Astrophysics Data System (ADS)

Boonyaritdachochai, Panida; Boonchuay, Chanwit; Ongsakul, Weerakorn

2010-06-01

This paper proposes an optimal power redispatching approach for congestion management in deregulated electricity market. Generator sensitivity is considered to indicate the redispatched generators. It can reduce the number of participating generators. The power adjustment cost and total redispatched power are minimized by particle swarm optimization with time varying acceleration coefficients (PSO-TVAC). The IEEE 30-bus and IEEE 118-bus systems are used to illustrate the proposed approach. Test results show that the proposed optimization scheme provides the lowest adjustment cost and redispatched power compared to the other schemes. The proposed approach is useful for the system operator to manage the transmission congestion.

Increasing Intelligence in Inter-Vehicle Communications to Reduce Traffic Congestions: Experiments in Urban and Highway Environments.

PubMed

Meneguette, Rodolfo I; Filho, Geraldo P R; Guidoni, Daniel L; Pessin, Gustavo; Villas, Leandro A; Ueyama, Jó

2016-01-01

Intelligent Transportation Systems (ITS) rely on Inter-Vehicle Communication (IVC) to streamline the operation of vehicles by managing vehicle traffic, assisting drivers with safety and sharing information, as well as providing appropriate services for passengers. Traffic congestion is an urban mobility problem, which causes stress to drivers and economic losses. In this context, this work proposes a solution for the detection, dissemination and control of congested roads based on inter-vehicle communication, called INCIDEnT. The main goal of the proposed solution is to reduce the average trip time, CO emissions and fuel consumption by allowing motorists to avoid congested roads. The simulation results show that our proposed solution leads to short delays and a low overhead. Moreover, it is efficient with regard to the coverage of the event and the distance to which the information can be propagated. The findings of the investigation show that the proposed solution leads to (i) high hit rate in the classification of the level of congestion, (ii) a reduction in average trip time, (iii) a reduction in fuel consumption, and (iv) reduced CO emissions.

Increasing Intelligence in Inter-Vehicle Communications to Reduce Traffic Congestions: Experiments in Urban and Highway Environments

PubMed Central

Filho, Geraldo P. R.; Guidoni, Daniel L.; Pessin, Gustavo; Villas, Leandro A.; Ueyama, Jó

2016-01-01

Intelligent Transportation Systems (ITS) rely on Inter-Vehicle Communication (IVC) to streamline the operation of vehicles by managing vehicle traffic, assisting drivers with safety and sharing information, as well as providing appropriate services for passengers. Traffic congestion is an urban mobility problem, which causes stress to drivers and economic losses. In this context, this work proposes a solution for the detection, dissemination and control of congested roads based on inter-vehicle communication, called INCIDEnT. The main goal of the proposed solution is to reduce the average trip time, CO emissions and fuel consumption by allowing motorists to avoid congested roads. The simulation results show that our proposed solution leads to short delays and a low overhead. Moreover, it is efficient with regard to the coverage of the event and the distance to which the information can be propagated. The findings of the investigation show that the proposed solution leads to (i) high hit rate in the classification of the level of congestion, (ii) a reduction in average trip time, (iii) a reduction in fuel consumption, and (iv) reduced CO emissions PMID:27526048

39 CFR 3.7 - Information furnished to Board-program review.

Code of Federal Regulations, 2010 CFR

2010-07-01

... visibility or the operating budget (including increases in expense amounts) or the capital investment budget...; (2) Five-year plans, annual operating and investment plans, and significant departures from estimates...

Modeling and Simulating Airport Surface Operations with Gate Conflicts

NASA Technical Reports Server (NTRS)

Zelinski, Shannon; Windhorst, Robert

2017-01-01

The Surface Operations Simulator and Scheduler (SOSS) is a fast-time simulation platform used to develop and test future surface scheduling concepts such as NASA's Air Traffic Demonstration 2 of time-based surface metering at Charlotte Douglass International Airport (CLT). Challenges associated with CLT surface operations have driven much of SOSS development. Recently, SOSS functionality for modeling harsdstand operations was developed to address gate conflicts, which occur when an arrival and departure wish to occupy the same gate at the same time. Because surface metering concepts such as ATD2 have the potential to increase gates conflicts as departures are held at their gates, it is important to study the interaction between surface metering and gate conflict management. Several approaches to managing gate conflicts with and without the use of hardstands were simulated and their effects on surface operations and scheduler performance compared.

Modeling and Simulating Airport Surface Operations with Gate Conflicts

NASA Technical Reports Server (NTRS)

Zelinski, Shannon; Windhorst, Robert

2017-01-01

The Surface Operations Simulator and Scheduler (SOSS) is a fast-time simulation platform used to develop and test future surface scheduling concepts such as NASAs Air Traffic Demonstration 2 of time-based surface metering at Charlotte Douglas International Airport (CLT). Challenges associated with CLT surface operations have driven much of SOSS development. Recently, SOSS functionality for modeling hardstand operations was developed to address gate conflicts, which occur when an arrival and departure wish to occupy the same gate at the same time. Because surface metering concepts such as ATD2 have the potential to increase gates conflicts as departure are held at their gates, it is important to study the interaction between surface metering and gate conflict management. Several approaches to managing gate conflicts with and without the use of hardstands were simulated and their effects on surface operations and scheduler performance compared.

Los Angeles congestion reduction demonstration (Metro ExpressLanes) program. National evaluation : safety data test plan.

DOT National Transportation Integrated Search

1999-07-01

This document presents human factors guidelines for designers, owners operators, and planners involved in the development and operation of traffic management centers. Dimensions of the work environment affecting operator and system performance are ad...

14 CFR 93.125 - Arrival or departure reservation.

Code of Federal Regulations, 2010 CFR

2010-01-01

... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES High Density Traffic Airports... may operate an aircraft to or from an airport designated as a high density traffic airport unless he...

14 CFR 93.125 - Arrival or departure reservation.

Code of Federal Regulations, 2014 CFR

2014-01-01

... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES High Density Traffic Airports... may operate an aircraft to or from an airport designated as a high density traffic airport unless he...

14 CFR 93.125 - Arrival or departure reservation.

Code of Federal Regulations, 2011 CFR

2011-01-01

... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES High Density Traffic Airports... may operate an aircraft to or from an airport designated as a high density traffic airport unless he...

14 CFR 93.125 - Arrival or departure reservation.

Code of Federal Regulations, 2012 CFR

2012-01-01

... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES High Density Traffic Airports... may operate an aircraft to or from an airport designated as a high density traffic airport unless he...

14 CFR 93.125 - Arrival or departure reservation.

Code of Federal Regulations, 2013 CFR

2013-01-01

... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES High Density Traffic Airports... may operate an aircraft to or from an airport designated as a high density traffic airport unless he...

A novel symbiotic organisms search algorithm for congestion management in deregulated environment

NASA Astrophysics Data System (ADS)

Verma, Sumit; Saha, Subhodip; Mukherjee, V.

2017-01-01

In today's competitive electricity market, managing transmission congestion in deregulated power system has created challenges for independent system operators to operate the transmission lines reliably within the limits. This paper proposes a new meta-heuristic algorithm, called as symbiotic organisms search (SOS) algorithm, for congestion management (CM) problem in pool based electricity market by real power rescheduling of generators. Inspired by interactions among organisms in ecosystem, SOS algorithm is a recent population based algorithm which does not require any algorithm specific control parameters unlike other algorithms. Various security constraints such as load bus voltage and line loading are taken into account while dealing with the CM problem. In this paper, the proposed SOS algorithm is applied on modified IEEE 30- and 57-bus test power system for the solution of CM problem. The results, thus, obtained are compared to those reported in the recent state-of-the-art literature. The efficacy of the proposed SOS algorithm for obtaining the higher quality solution is also established.

A novel symbiotic organisms search algorithm for congestion management in deregulated environment

NASA Astrophysics Data System (ADS)

Verma, Sumit; Saha, Subhodip; Mukherjee, V.

2017-01-01

In today's competitive electricity market, managing transmission congestion in deregulated power system has created challenges for independent system operators to operate the transmission lines reliably within the limits. This paper proposes a new meta-heuristic algorithm, called as symbiotic organisms search (SOS) algorithm, for congestion management (CM) problem in pool-based electricity market by real power rescheduling of generators. Inspired by interactions among organisms in ecosystem, SOS algorithm is a recent population-based algorithm which does not require any algorithm specific control parameters unlike other algorithms. Various security constraints such as load bus voltage and line loading are taken into account while dealing with the CM problem. In this paper, the proposed SOS algorithm is applied on modified IEEE 30- and 57-bus test power system for the solution of CM problem. The results, thus, obtained are compared to those reported in the recent state-of-the-art literature. The efficacy of the proposed SOS algorithm for obtaining the higher quality solution is also established.

Information Requirements for Supervisory Air Traffic Controllers in Support of a Mid-Term Wake Vortex Departure System

NASA Technical Reports Server (NTRS)

Lohr, Gary W.; Williams, Daniel M.; Trujillo, Anna C.; Johnson, Edward J.; Domino, David A.

2008-01-01

A concept focusing on wind dependent departure operations has been developed the current version of this concept is called the Wake Turbulence Mitigation for Departures (WTMD). This concept takes advantage the fact that cross winds of sufficient velocity blow wakes generated by "heavy" and B757 category aircraft on the downwind runway away from the upwind runway. Supervisory Air Traffic Controllers would be responsible for authorization of the Procedure. An investigation of the information requirements necessary to for Supervisors to approve monitor and terminate the Procedure was conducted. Results clearly indicated that the requisite information is currently available in air traffic control towers and that additional information was not required.

Airspace Technology Demonstration 2 (ATD-2) Phase 1 Concept of Use (ConUse)

NASA Technical Reports Server (NTRS)

Jung, Yoon; Engelland, Shawn; Capps, Richard; Coppenbarger, Rich; Hooey, Becky; Sharma, Shivanjli; Stevens, Lindsay; Verma, Savita; Lohr, Gary; Chevalley, Eric;

A Mixed Integer Linear Program for Airport Departure Scheduling

NASA Technical Reports Server (NTRS)

Gupta, Gautam; Jung, Yoon Chul

2009-01-01

Aircraft departing from an airport are subject to numerous constraints while scheduling departure times. These constraints include wake-separation constraints for successive departures, miles-in-trail separation for aircraft bound for the same departure fixes, and time-window or prioritization constraints for individual flights. Besides these, emissions as well as increased fuel consumption due to inefficient scheduling need to be included. Addressing all the above constraints in a single framework while allowing for resequencing of the aircraft using runway queues is critical to the implementation of the Next Generation Air Transport System (NextGen) concepts. Prior work on airport departure scheduling has addressed some of the above. However, existing methods use pre-determined runway queues, and schedule aircraft from these departure queues. The source of such pre-determined queues is not explicit, and could potentially be a subjective controller input. Determining runway queues and scheduling within the same framework would potentially result in better scheduling. This paper presents a mixed integer linear program (MILP) for the departure-scheduling problem. The program takes as input the incoming sequence of aircraft for departure from a runway, along with their earliest departure times and an optional prioritization scheme based on time-window of departure for each aircraft. The program then assigns these aircraft to the available departure queues and schedules departure times, explicitly considering wake separation and departure fix restrictions to minimize total delay for all aircraft. The approach is generalized and can be used in a variety of situations, and allows for aircraft prioritization based on operational as well as environmental considerations. We present the MILP in the paper, along with benefits over the first-come-first-serve (FCFS) scheme for numerous randomized problems based on real-world settings. The MILP results in substantially reduced delays as compared to FCFS, and the magnitude of the savings depends on the queue and departure fix structure. The MILP assumes deterministic aircraft arrival times at the runway queues. However, due to taxi time uncertainty, aircraft might arrive either earlier or later than these deterministic times. Thus, to incorporate this uncertainty, we present a method for using the MILP with "overlap discounted rolling planning horizon". The approach is based on valuing near-term decision results more than future ones. We develop a model of taxitime uncertainty based on real-world data, and then compare the baseline FCFS delays with delays using the above MILP in a simple rolling-horizon method and in the overlap discounted scheme.

Improving Deterministic Reserve Requirements for Security Constrained Unit Commitment and Scheduling Problems in Power Systems

NASA Astrophysics Data System (ADS)

Wang, Fengyu

Traditional deterministic reserve requirements rely on ad-hoc, rule of thumb methods to determine adequate reserve in order to ensure a reliable unit commitment. Since congestion and uncertainties exist in the system, both the quantity and the location of reserves are essential to ensure system reliability and market efficiency. The modeling of operating reserves in the existing deterministic reserve requirements acquire the operating reserves on a zonal basis and do not fully capture the impact of congestion. The purpose of a reserve zone is to ensure that operating reserves are spread across the network. Operating reserves are shared inside each reserve zone, but intra-zonal congestion may block the deliverability of operating reserves within a zone. Thus, improving reserve policies such as reserve zones may improve the location and deliverability of reserve. As more non-dispatchable renewable resources are integrated into the grid, it will become increasingly difficult to predict the transfer capabilities and the network congestion. At the same time, renewable resources require operators to acquire more operating reserves. With existing deterministic reserve requirements unable to ensure optimal reserve locations, the importance of reserve location and reserve deliverability will increase. While stochastic programming can be used to determine reserve by explicitly modelling uncertainties, there are still scalability as well as pricing issues. Therefore, new methods to improve existing deterministic reserve requirements are desired. One key barrier of improving existing deterministic reserve requirements is its potential market impacts. A metric, quality of service, is proposed in this thesis to evaluate the price signal and market impacts of proposed hourly reserve zones. Three main goals of this thesis are: 1) to develop a theoretical and mathematical model to better locate reserve while maintaining the deterministic unit commitment and economic dispatch structure, especially with the consideration of renewables, 2) to develop a market settlement scheme of proposed dynamic reserve policies such that the market efficiency is improved, 3) to evaluate the market impacts and price signal of the proposed dynamic reserve policies.

14 CFR 91.303 - Aerobatic flight.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Aerobatic flight. 91.303 Section 91.303... AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT RULES Special Flight Operations § 91.303 Aerobatic flight. No person may operate an aircraft in aerobatic flight— (a) Over any congested area of a...

14 CFR 91.303 - Aerobatic flight.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Aerobatic flight. 91.303 Section 91.303... AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT RULES Special Flight Operations § 91.303 Aerobatic flight. No person may operate an aircraft in aerobatic flight— (a) Over any congested area of a...

14 CFR 91.303 - Aerobatic flight.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Aerobatic flight. 91.303 Section 91.303... AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT RULES Special Flight Operations § 91.303 Aerobatic flight. No person may operate an aircraft in aerobatic flight— (a) Over any congested area of a...

14 CFR 91.303 - Aerobatic flight.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Aerobatic flight. 91.303 Section 91.303... AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT RULES Special Flight Operations § 91.303 Aerobatic flight. No person may operate an aircraft in aerobatic flight— (a) Over any congested area of a...

14 CFR 91.303 - Aerobatic flight.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Aerobatic flight. 91.303 Section 91.303... AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT RULES Special Flight Operations § 91.303 Aerobatic flight. No person may operate an aircraft in aerobatic flight— (a) Over any congested area of a...

Guidelines for the operation of variable message signs on state highways

DOT National Transportation Integrated Search

2004-06-01

A variable message sign (VMS) is a traffic control device whose message can be changed manually, electrically, mechanically, or electromechanically to provide motorists with information about traffic congestion, traffic crashes, maintenance operation...

Contributions of aircraft arrivals and departures to ultrafine particle counts near Los Angeles International Airport.

PubMed

Hsu, Hsiao-Hsien; Adamkiewicz, Gary; Houseman, E Andres; Zarubiak, Darcy; Spengler, John D; Levy, Jonathan I

2013-02-01

While commercial aircraft are known sources of ultrafine particulate matter (UFP), the relationship between airport activity and local real-time UFP concentrations has not been quantified. Understanding these associations will facilitate interpretation of the exposure and health risk implications of UFP related to aviation emissions. We used time-resolved UFP data along with flight activity and meteorological information to determine the contributions of aircraft departures and arrivals to UFP concentrations. Aircraft flight activity and near-field continuous UFP concentrations (≧ 6 nm) were measured at five monitoring sites over a 42-day field campaign at Los Angeles International Airport (LAX). We developed regression models of UFP concentrations as a function of time-lagged landing and take-off operations (LTO) activity, in the form of arrivals or departures weighted by engine-specific estimates of fuel consumption. Our regression models demonstrate a strong association between departures and elevated total UFP concentrations at the end of the departure runway, with diminishing magnitude and time-lagged impacts with distance from the source. LTO activity contributed a median (95th, 99th percentile) UFP concentration of approximately 150,000 particles/cm(3) (2,000,000, 7,100,000) at a monitor at the end of the departure runway, versus 19,000 particles/cm(3) (80,000, 140,000), and 17,000 particles/cm(3) (50,000, 72,000) for monitors 250 m and 500 m further downwind, respectively. We demonstrated significant contributions from aircraft departure activities to UFP concentrations in close proximity to departure runways, with evidence of rapid plume evolution in the near field. Our methods can inform source attribution and interpretation of dispersion modeling outputs. Copyright © 2012 Elsevier B.V. All rights reserved.

Performance Evaluation of Individual Aircraft Based Advisory Concept for Surface Management

NASA Technical Reports Server (NTRS)

Gupta, Gautam; Malik, Waqar; Tobias, Leonard; Jung, Yoon; Hong, Ty; Hayashi, Miwa

2013-01-01

Surface operations at airports in the US are based on tactical operations, where departure aircraft primarily queue up and wait at the departure runways. NASA's Spot And Runway Departure Advisor (SARDA) tool was developed to address these inefficiencies through Air Traffic Control Tower advisories. The SARDA system is being updated to include collaborative gate hold, either tactically or strategically. This paper presents the results of the human-in-the-loop evaluation of the tactical gate hold version of SARDA in a 360 degree simulated tower setting. The simulations were conducted for the east side of the Dallas/Fort Worth airport. The new system provides gate hold, ground controller and local controller advisories based on a single scheduler. Simulations were conducted with SARDA on and off, the off case reflecting current day operations with no gate hold. Scenarios based on medium (1.2x current levels) and heavy (1.5x current levels) traffic were explored. Data collected from the simulation was analyzed for runway usage, delay for departures and arrivals, and fuel consumption. Further, Traffic Management Initiatives were introduced for a subset of the aircraft. Results indicated that runway usage did not change with the use of SARDA, i.e., there was no loss in runway throughput as compared to baseline. Taxiing delay was significantly reduced with the use of advisory by 45% in medium scenarios and 60% in heavy. Arrival delay was unaffected by the use of advisory. Total fuel consumption was also reduced by 23% in medium traffic and 33% in heavy. TMI compliance appeared unaffected by the advisory

Performance Evaluation of SARDA: An Individual Aircraft-Based Advisory Concept for Surface Management

NASA Technical Reports Server (NTRS)

Jung, Yoon; Malik, Waqar; Tobias, Leonard; Gupta, Gautam; Hoang, Ty; Hayashi, Miwa

2015-01-01

Surface operations at airports in the US are based on tactical operations, where departure aircraft primarily queue up and wait at the departure runways. NASAs Spot And Runway Departure Advisor (SARDA) tool was developed to address these inefficiencies through Air Traffic Control Tower advisories. The SARDA system is being updated to include collaborative gate hold, either tactically or strategically. This paper presents the results of the human-in-the-loop evaluation of the tactical gate hold version of SARDA in a 360 degree simulated tower setting. The simulations were conducted for the east side of the Dallas-Fort Worth airport. The new system provides gate hold, ground controller and local controller advisories based on a single scheduler. Simulations were conducted with SARDA on and off, the off case reflecting current day operations with no gate hold. Scenarios based on medium (1.2x current levels) and heavy (1.5x current levels) traffic were explored. Data collected from the simulation was analyzed for runway usage, delay for departures and arrivals, and fuel consumption. Further, Traffic Management Initiatives were introduced for a subset of the aircraft. Results indicated that runway usage did not change with the use of SARDA, i.e., there was no loss in runway throughput as compared to baseline. Taxiing delay was significantly reduced with the use of advisory by 45 in medium scenarios and 60 in heavy. Arrival delay was unaffected by the use of advisory. Total fuel consumption was also reduced by 23 in medium traffic and 33 in heavy. TMI compliance appeared unaffected by the advisory.

System-Oriented Runway Management Concept of Operations

NASA Technical Reports Server (NTRS)

Lohr, Gary W.; Atkins, Stephen

2015-01-01

This document describes a concept for runway management that maximizes the overall efficiency of arrival and departure operations at an airport or group of airports. Specifically, by planning airport runway configurations/usage, it focuses on the efficiency with which arrival flights reach their parking gates from their arrival fixes and departure flights exit the terminal airspace from their parking gates. In the future, the concept could be expanded to include the management of other limited airport resources. While most easily described in the context of a single airport, the concept applies equally well to a group of airports that comprise a metroplex (i.e., airports in close proximity that share resources such that operations at the airports are at least partially dependent) by including the coordination of runway usage decisions between the airports. In fact, the potential benefit of the concept is expected to be larger in future metroplex environments due to the increasing need to coordinate the operations at proximate airports to more efficiently share limited airspace resources. This concept, called System-Oriented Runway Management (SORM), is further broken down into a set of airport traffic management functions that share the principle that operational performance must be measured over the complete surface and airborne trajectories of the airport's arrivals and departures. The "system-oriented" term derives from the belief that the traffic management objective must consider the efficiency of operations over a wide range of aircraft movements and National Airspace System (NAS) dynamics. The SORM concept is comprised of three primary elements: strategic airport capacity planning, airport configuration management, and combined arrival/departure runway planning. Some aspects of the SORM concept, such as using airport configuration management1 as a mechanism for improving aircraft efficiency, are novel. Other elements (e.g., runway scheduling, which is a part of combined arrival/departure runway scheduling) have been well studied, but are included in the concept for completeness and to allow the concept to define the necessary relationship among the elements. The goal of this document is to describe the overall SORM concept and how it would apply both within the NAS and potential future Next Generation Air Traffic System (NextGen) environments, including research conducted to date. Note that the concept is based on the belief that runways are the primary constraint and the decision point for controlling efficiency, but the efficiency of runway management must be measured over a wide range of space and time. Implementation of the SORM concept is envisioned through a collection of complementary, necessary capabilities collectively focused on ensuring efficient arrival and departure traffic management, where that efficiency is measured not only in terms of runway efficiency but in terms of the overall trajectories between parking gates and transition fixes. For the more original elements of the concept-airport configuration management-this document proposes specific air traffic management (ATM) decision-support automation for realizing the concept.

[A case report of Ebstein's anomaly treated with Hetzer's procedure].

PubMed

Sako, H; Hadama, T; Shigemitsu, O; Miyamoto, S; Anai, H; Wada, T; Iwata, E; Mori, Y; Soeda, T; Takakura, K

2001-02-01

A 27-year-old male who had been diagnosed with Ebstein's anomaly was admitted with uncontrollable congestive heart failure. The echocardiogram revealed severe tricuspid valve incompetence and the electrocardiogram showed atrial fibrillation. He underwent Hetzer's repair procedure for tricuspid valve incompetence and Minzioni's right atrial isolation technique to restore sinus rhythm. His congestive heart failure quickly disappeared and sinus rhythm was restored after operation. He was discharged 3 weeks postoperatively and remains well 22 months after his operation. Hetzer's technique for tricuspid valve repair in Ebstein's anomaly restructures the valve mechanism at the level of the true tricuspid anulus by using the most mobile leaflet for valve closure without plication of the atrialized chamber. We conclude that Hetzer's procedure is an effective operation for Ebstein's anomaly.

40 CFR 93.153 - Applicability.

Code of Federal Regulations, 2012 CFR

2012-07-01

... operation to activities currently being conducted. (xii) Planning, studies, and provision of technical... control activities and adopting approach, departure, and enroute procedures for aircraft operations above... (e) of this section. (3) Research, investigations, studies, demonstrations, or training (other than...

40 CFR 93.153 - Applicability.

Code of Federal Regulations, 2013 CFR

2013-07-01

... operation to activities currently being conducted. (xii) Planning, studies, and provision of technical... control activities and adopting approach, departure, and enroute procedures for aircraft operations above... (e) of this section. (3) Research, investigations, studies, demonstrations, or training (other than...

40 CFR 93.153 - Applicability.

Code of Federal Regulations, 2014 CFR

2014-07-01

... operation to activities currently being conducted. (xii) Planning, studies, and provision of technical... control activities and adopting approach, departure, and enroute procedures for aircraft operations above... (e) of this section. (3) Research, investigations, studies, demonstrations, or training (other than...

Optimizing Integrated Terminal Airspace Operations Under Uncertainty

NASA Technical Reports Server (NTRS)

Bosson, Christabelle; Xue, Min; Zelinski, Shannon

2014-01-01

In the terminal airspace, integrated departures and arrivals have the potential to increase operations efficiency. Recent research has developed geneticalgorithm- based schedulers for integrated arrival and departure operations under uncertainty. This paper presents an alternate method using a machine jobshop scheduling formulation to model the integrated airspace operations. A multistage stochastic programming approach is chosen to formulate the problem and candidate solutions are obtained by solving sample average approximation problems with finite sample size. Because approximate solutions are computed, the proposed algorithm incorporates the computation of statistical bounds to estimate the optimality of the candidate solutions. A proof-ofconcept study is conducted on a baseline implementation of a simple problem considering a fleet mix of 14 aircraft evolving in a model of the Los Angeles terminal airspace. A more thorough statistical analysis is also performed to evaluate the impact of the number of scenarios considered in the sampled problem. To handle extensive sampling computations, a multithreading technique is introduced.

Assessing Impact of Dual Sensor Enhanced Flight Vision Systems on Departure Performance

NASA Technical Reports Server (NTRS)

Kramer, Lynda J.; Etherington, Timothy J.; Severance, Kurt; Bailey, Randall E.

2016-01-01

Synthetic Vision (SV) and Enhanced Flight Vision Systems (EFVS) may serve as game-changing technologies to meet the challenges of the Next Generation Air Transportation System and the envisioned Equivalent Visual Operations (EVO) concept - that is, the ability to achieve the safety and operational tempos of current-day Visual Flight Rules operations irrespective of the weather and visibility conditions. One significant obstacle lies in the definition of required equipage on the aircraft and on the airport to enable the EVO concept objective. A motion-base simulator experiment was conducted to evaluate the operational feasibility and pilot workload of conducting departures and approaches on runways without centerline lighting in visibility as low as 300 feet runway visual range (RVR) by use of onboard vision system technologies on a Head-Up Display (HUD) without need or reliance on natural vision. Twelve crews evaluated two methods of combining dual sensor (millimeter wave radar and forward looking infrared) EFVS imagery on pilot-flying and pilot-monitoring HUDs. In addition, the impact of adding SV to the dual sensor EFVS imagery on crew flight performance and workload was assessed. Using EFVS concepts during 300 RVR terminal operations on runways without centerline lighting appears feasible as all EFVS concepts had equivalent (or better) departure performance and landing rollout performance, without any workload penalty, than those flown with a conventional HUD to runways having centerline lighting. Adding SV imagery to EFVS concepts provided situation awareness improvements but no discernible improvements in flight path maintenance.

14 CFR 91.129 - Operations in Class D airspace.

Code of Federal Regulations, 2014 CFR

2014-01-01

...) Unless required by the applicable distance-from-cloud criteria, each pilot operating a large or turbine... applicable distance-from-cloud criteria requires glide path interception closer in, operate that airplane at... required by the prescribed departure procedure for that airport or the applicable distance from clouds...

14 CFR 91.129 - Operations in Class D airspace.

Code of Federal Regulations, 2013 CFR

2013-01-01

...) Unless required by the applicable distance-from-cloud criteria, each pilot operating a large or turbine... applicable distance-from-cloud criteria requires glide path interception closer in, operate that airplane at... required by the prescribed departure procedure for that airport or the applicable distance from clouds...

14 CFR 91.129 - Operations in Class D airspace.

Code of Federal Regulations, 2012 CFR

2012-01-01

...) Unless required by the applicable distance-from-cloud criteria, each pilot operating a large or turbine... applicable distance-from-cloud criteria requires glide path interception closer in, operate that airplane at... required by the prescribed departure procedure for that airport or the applicable distance from clouds...

14 CFR 91.129 - Operations in Class D airspace.

Code of Federal Regulations, 2011 CFR

2011-01-01

...) Unless required by the applicable distance-from-cloud criteria, each pilot operating a large or turbine... applicable distance-from-cloud criteria requires glide path interception closer in, operate that airplane at... required by the prescribed departure procedure for that airport or the applicable distance from clouds...

Improvement of Efficiency of Transportation in Harbor Physical Distribution Considering Inland Carriage

NASA Astrophysics Data System (ADS)

Hino, Hisato; Hoshino, Satoshi; Fujisawa, Tomoharu; Maruyama, Shigehisa; Ota, Jun

Currently, container ships move cargo with minimal participation from external trucks. However, there is slack time between the departure of container ships and the completion of cargo handling by container ships without the participation of external trucks; therefore, external trucks can be used to move cargo without delaying the departure time. In this paper, we propose a solution involving the control algorithms of transfer cranes (TCs) because the efficiency of yard operations depends largely on the productivity of TCs. TCs work according to heuristic rules using the forecasted arrival times of internal and external trucks. Simulation results show that the proposed method can reduce the waiting time of external trucks and meet the departure time of container ships.

14 CFR 93.31 - Minimum usage requirement.

Code of Federal Regulations, 2011 CFR

2011-01-01

... operating Carrier used for air traffic control communications, scheduled time of operation, origin airport...) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Congestion and Delay Reduction at... shall identify any Common Ownership or control of, by, or with any other carrier. A senior official of...

14 CFR 93.31 - Minimum usage requirement.

Code of Federal Regulations, 2010 CFR

2010-01-01

... operating Carrier used for air traffic control communications, scheduled time of operation, origin airport...) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Congestion and Delay Reduction at... shall identify any Common Ownership or control of, by, or with any other carrier. A senior official of...

77 FR 30585 - Operating Limitations at New York LaGuardia Airport; Technical Amendment

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-23

... limiting operations at LaGuardia Airport until the final Congestion Management Rule for LaGuardia Airport... this Order contact: Patricia Bynum, System Operations Services, Air Traffic Organization, Federal... Limiting Operations at New York LaGuardia Airport (LGA).\\1\\ As a result of the extension, the Order remains...

Revised Point of Departure Design Options for Nuclear Thermal Propulsion

NASA Technical Reports Server (NTRS)

Fittje, James E.; Schnitzler, Bruce G.; Borowoski, Stanley

2015-01-01

Four Revised Point of Departure NTR Engines were Designed and Analyzed using MCNP and NESS. All Four Engines Have Thermodynamically Closed Cycles at Nominal Chamber Pressures. 111 kilonewton (25 kip-force) Cermet Design Required Dedicated Heater Elements to Close the Cycle. Cermet Based Designs had Slightly Higher TW Ratios, but Required Substantially More U-235. NERVA Derived Criticality Limited Engine Could Operate at Lower Power and Thrust Levels Compared to the Criticality Limited Cermet Design.

NextGen Operational Improvements: Will they Improve Human Performance

NASA Technical Reports Server (NTRS)

Beard, Bettina L.; Johnston, James C.; Holbrook, Jon

2013-01-01

Modernization of the National Airspace System depends critically on the development of advanced technology, including cutting-edge automation, controller decision-support tools and integrated on-demand information. The Next Generation Air Transportation System national plan envisions air traffic control tower automation that proposes solutions for seven problems: 1) departure metering, 2) taxi routing, 3) taxi and runway scheduling, 4) departure runway assignments, 5) departure flow management, 6) integrated arrival and departure scheduling and 7) runway configuration management. Government, academia and industry are simultaneously pursuing the development of these tools. For each tool, the development process typically begins by assessing its potential benefits, and then progresses to designing preliminary versions of the tool, followed by testing the tool's strengths and weaknesses using computational modeling, human-in-the-loop simulation and/or field tests. We compiled the literature, evaluated the methodological rigor of the studies and served as referee for partisan conclusions that were sometimes overly optimistic. Here we provide the results of this review.

Visual Analysis of Air Traffic Data

NASA Technical Reports Server (NTRS)

Albrecht, George Hans; Pang, Alex

2012-01-01

In this paper, we present visual analysis tools to help study the impact of policy changes on air traffic congestion. The tools support visualization of time-varying air traffic density over an area of interest using different time granularity. We use this visual analysis platform to investigate how changing the aircraft separation volume can reduce congestion while maintaining key safety requirements. The same platform can also be used as a decision aid for processing requests for unmanned aerial vehicle operations.

Congestion Pricing for Aircraft Pushback Slot Allocation.

PubMed

Liu, Lihua; Zhang, Yaping; Liu, Lan; Xing, Zhiwei

2017-01-01

In order to optimize aircraft pushback management during rush hour, aircraft pushback slot allocation based on congestion pricing is explored while considering monetary compensation based on the quality of the surface operations. First, the concept of the "external cost of surface congestion" is proposed, and a quantitative study on the external cost is performed. Then, an aircraft pushback slot allocation model for minimizing the total surface cost is established. An improved discrete differential evolution algorithm is also designed. Finally, a simulation is performed on Xinzheng International Airport using the proposed model. By comparing the pushback slot control strategy based on congestion pricing with other strategies, the advantages of the proposed model and algorithm are highlighted. In addition to reducing delays and optimizing the delay distribution, the model and algorithm are better suited for use for actual aircraft pushback management during rush hour. Further, it is also observed they do not result in significant increases in the surface cost. These results confirm the effectiveness and suitability of the proposed model and algorithm.

Modeling and analyzing cascading dynamics of the Internet based on local congestion information

NASA Astrophysics Data System (ADS)

Zhu, Qian; Nie, Jianlong; Zhu, Zhiliang; Yu, Hai; Xue, Yang

2018-06-01

Cascading failure has already become one of the vital issues in network science. By considering realistic network operational settings, we propose the congestion function to represent the congested extent of node and construct a local congestion-aware routing strategy with a tunable parameter. We investigate the cascading failures on the Internet triggered by deliberate attacks. Simulation results show that the tunable parameter has an optimal value that makes the network achieve a maximum level of robustness. The robustness of the network has a positive correlation with tolerance parameter, but it has a negative correlation with the packets generation rate. In addition, there exists a threshold of the attacking proportion of nodes that makes the network achieve the lowest robustness. Moreover, by introducing the concept of time delay for information transmission on the Internet, we found that an increase of the time delay will decrease the robustness of the network rapidly. The findings of the paper will be useful for enhancing the robustness of the Internet in the future.

A self-adaptive toll rate algorithm for high occupancy toll (HOT) lane operations.

DOT National Transportation Integrated Search

2009-12-01

Dramatically increasing travel demands and insufficient traffic facility supplies have resulted in severe : traffic congestion. High Occupancy Toll (HOT) lane operations have been proposed as one of the most : applicable and cost-effective countermea...

76 FR 18616 - Operating Limitations at New York LaGuardia Airport

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-04

... under the same marketing control up to 5 business days after the actual operation. This post-transfer... of Extension to Order. SUMMARY: This action amends the Order Limiting Operations at New York..., 2008, and October 7, 2009. The Order remains effective until the final Congestion Management Rule for...

Analysis on logistic company action toward the access restriction policy on freight vehicle

NASA Astrophysics Data System (ADS)

Nur, Muhammad; Hadiwardoyo, Sigit P.; Nahry, Nahdalina

2017-06-01

The high volume of freight vehicles that enters, leaves or passes through the urban areas, especially Jakarta, has caused traffic congestion. Local authority plans to perform the access restriction on freight vehicles on the Jakarta Outer Ring Road (JORR) to reduce the congestion on that toll road. The study aims to analyze the alternative solutions of the logistics companies to overcome the impact of such policy. The data collection is done by interviewing 102 truck drivers and 7 staffs of logistic companies that use JORR. The results show that the most preferred action is shifting the operating time. Based on the open test, access restriction policy on JORR may cause a significant impact on the operational costs of delivery. Shifting the operational time will increase the operating cost by 1.71%, while turning the route will increase the operating costs by 4.35%. Moreover, changing the mode will reduce the operating expenses by 50%, and the combination action of shifting the route and the time will increase the operating costs by 5.39%.

Multi-objective Optimization of Departure Procedures at Gimpo International Airport

NASA Astrophysics Data System (ADS)

Kim, Junghyun; Lim, Dongwook; Monteiro, Dylan Jonathan; Kirby, Michelle; Mavris, Dimitri

2018-04-01

Most aviation communities have increasing concerns about the environmental impacts, which are directly linked to health issues for local residents near the airport. In this study, the environmental impact of different departure procedures using the Aviation Environmental Design Tool (AEDT) was analyzed. First, actual operational data were compiled at Gimpo International Airport (March 20, 2017) from an open source. Two modifications were made in the AEDT to model the operational circumstances better and the preliminary AEDT simulations were performed according to the acquired operational procedures. Simulated noise results showed good agreements with noise measurement data at specific locations. Second, a multi-objective optimization of departure procedures was performed for the Boeing 737-800. Four design variables were selected and AEDT was linked to a variety of advanced design methods. The results showed that takeoff thrust had the greatest influence and it was found that fuel burn and noise had an inverse relationship. Two points representing each fuel burn and noise optimum on the Pareto front were parsed and run in AEDT to compare with the baseline. The results showed that the noise optimum case reduced Sound Exposure Level 80-dB noise exposure area by approximately 5% while the fuel burn optimum case reduced total fuel burn by 1% relative to the baseline for aircraft-level analysis.

A comparison of operational performance : Washington state ferries to ferry operators worldwide.

DOT National Transportation Integrated Search

2010-06-01

This project compares eight measures of performance related to transit service quality (e.g. trip reliability, on-time departures) and cost-efficiency (e.g. farebox recovery, subsidy per passenger) between Washington State Ferries (WSF) and 23 ferry ...

14 CFR 91.709 - Operations to Cuba.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Operations to Cuba. 91.709 Section 91.709... Board Such Aircraft § 91.709 Operations to Cuba. No person may operate a civil aircraft from the United States to Cuba unless— (a) Departure is from an international airport of entry designated in § 6.13 of...

14 CFR 91.709 - Operations to Cuba.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Operations to Cuba. 91.709 Section 91.709... Board Such Aircraft § 91.709 Operations to Cuba. No person may operate a civil aircraft from the United States to Cuba unless— (a) Departure is from an international airport of entry designated in § 6.13 of...

14 CFR 91.709 - Operations to Cuba.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Operations to Cuba. 91.709 Section 91.709... Board Such Aircraft § 91.709 Operations to Cuba. No person may operate a civil aircraft from the United States to Cuba unless— (a) Departure is from an international airport of entry designated in § 6.13 of...

14 CFR 91.709 - Operations to Cuba.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Operations to Cuba. 91.709 Section 91.709... Board Such Aircraft § 91.709 Operations to Cuba. No person may operate a civil aircraft from the United States to Cuba unless— (a) Departure is from an international airport of entry designated in § 6.13 of...

14 CFR 91.709 - Operations to Cuba.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Operations to Cuba. 91.709 Section 91.709... Board Such Aircraft § 91.709 Operations to Cuba. No person may operate a civil aircraft from the United States to Cuba unless— (a) Departure is from an international airport of entry designated in § 6.13 of...

Exploiting New Data Sources to Quantify Arterial Congestion and Performance Measures.

DOT National Transportation Integrated Search

2017-01-01

Transit travel time, operating speed and reliability all influence service attractiveness, operating cost and system efficiency. These metrics have a long-term impact on system effectiveness through a change in ridership. As part of its bus dispatch ...

SpaceX Dragon before Departure

NASA Image and Video Library

2016-05-11

ISS047e109559 (05/11/2016) --- The SpaceX Dragon is seen berthed to the Earth-facing side of the station’s Harmony module shortly before departure. The vehicle was ultimately released by Expedition 47 robotic arm operator Tim Peake of ESA (European Space Agency) at 9:18 a.m. EDT. Dragon returned to Earth carrying more than 3,700 pounds of NASA cargo and science samples from human research, biology and biotechnology studies, physical science investigations and education activities sponsored by NASA and the U.S. national laboratory.

Wake Turbulence Mitigation for Departures (WTMD) Prototype System - Software Design Document

NASA Technical Reports Server (NTRS)

Sturdy, James L.

2008-01-01

This document describes the software design of a prototype Wake Turbulence Mitigation for Departures (WTMD) system that was evaluated in shadow mode operation at the Saint Louis (KSTL) and Houston (KIAH) airports. This document describes the software that provides the system framework, communications, user displays, and hosts the Wind Forecasting Algorithm (WFA) software developed by the M.I.T. Lincoln Laboratory (MIT-LL). The WFA algorithms and software are described in a separate document produced by MIT-LL.

Three essays on access pricing

NASA Astrophysics Data System (ADS)

Sydee, Ahmed Nasim

In the first essay, a theoretical model is developed to determine the time path of optimal access price in the telecommunications industry. Determining the optimal access price is an important issue in the economics of telecommunications. Setting a high access price discourages potential entrants; a low access price, on the other hand, amounts to confiscation of private property because the infrastructure already built by the incumbent is sunk. Furthermore, a low access price does not give the incumbent incentives to maintain the current network and to invest in new infrastructures. Much of the existing literature on access pricing suffers either from the limitations of a static framework or from the assumption that all costs are avoidable. The telecommunications industry is subject to high stranded costs and, therefore, to address this issue a dynamic model is imperative. This essay presents a dynamic model of one-way access pricing in which the compensation involved in deregulatory taking is formalized and then analyzed. The short run adjustment after deregulatory taking has occurred is carried out and discussed. The long run equilibrium is also analyzed. A time path for the Ramsey price is shown as the correct dynamic price of access. In the second essay, a theoretical model is developed to determine the time path of optimal access price for an infrastructure that is characterized by congestion and lumpy investment. Much of the theoretical literature on access pricing of infrastructure prescribes that the access price be set at the marginal cost of the infrastructure. In proposing this rule of access pricing, the conventional analysis assumes that infrastructure investments are infinitely divisible so that it makes sense to talk about the marginal cost of investment. Often it is the case that investments in infrastructure are lumpy and can only be made in large chunks, and this renders the marginal cost concept meaningless. In this essay, we formalize a model of access pricing with congestion and in which investments in infrastructure are lumpy. To fix ideas, the model is formulated in the context of airport infrastructure investments, which captures both the element of congestion and the lumpiness involved in infrastructure investments. The optimal investment program suggests how many units of capacity should be installed and at which times. Because time is continuous in the model, the discounted cost -- despite the lumpiness of capacity additions -- can be made to vary continuously by varying the time a capacity addition is made. The main results that emerge from the analysis can be described as follows: First, the global demand for air travel rises with time and experiences an upward jump whenever a capacity addition is made. Second, the access price is constant and stays at the basic level when the system is not congested. When the system is congested, a congestion surcharge is imposed on top of the basic level, and the congestion surcharge rises with the level of congestion until the next capacity addition is made at which time the access price takes a downward jump. Third, the individual demand for air travel is constant before congestion sets in and after the last capacity addition takes place. During a time interval in which congestion rises, the individual demand for travel is below the level that prevails when there is no congestion and declines as congestion worsens. The third essay contains a model of access pricing for natural gas transmission pipelines, both when pipeline operators are regulated and when they behave strategically. The high sunk costs involved in building a pipeline network constitute a serious barrier of entry, and competitive behaviour in the transmission pipeline sector cannot be expected. Most of the economic analyses of access pricing for natural gas transmission pipelines are carried out from the regulatory perspective, and the access price paid by shippers are cost-based. The model formalized is intended to capture some essential characteristics of networks in which components interact with one another when combined into an integrated system. The model shows how the topology of the network determines the access prices in different components of the network. The general results that emerge from the analysis can be summarized as follows. First, the monopoly power of a pipeline operator is reduced by the entry of a new pipeline supply connected in parallel to the same demand node. When the pipelines are connected in series, the one upstream enjoys a first-move advantage over the one downstream, and the toll set by the upstream pipeline operator after entry by the downstream pipeline operator will rise above the original monopoly level. The equilibrium prices of natural gas at the various nodes of the network are also discussed. (Abstract shortened by UMI.)

Random early detection for congestion avoidance in wired networks: a discretized pursuit learning-automata-like solution.

PubMed

Misra, Sudip; Oommen, B John; Yanamandra, Sreekeerthy; Obaidat, Mohammad S

2010-02-01

In this paper, we present a learning-automata-like The reason why the mechanism is not a pure LA, but rather why it yet mimics one, will be clarified in the body of this paper. (LAL) mechanism for congestion avoidance in wired networks. Our algorithm, named as LAL Random Early Detection (LALRED), is founded on the principles of the operations of existing RED congestion-avoidance mechanisms, augmented with a LAL philosophy. The primary objective of LALRED is to optimize the value of the average size of the queue used for congestion avoidance and to consequently reduce the total loss of packets at the queue. We attempt to achieve this by stationing a LAL algorithm at the gateways and by discretizing the probabilities of the corresponding actions of the congestion-avoidance algorithm. At every time instant, the LAL scheme, in turn, chooses the action that possesses the maximal ratio between the number of times the chosen action is rewarded and the number of times that it has been chosen. In LALRED, we simultaneously increase the likelihood of the scheme converging to the action, which minimizes the number of packet drops at the gateway. Our approach helps to improve the performance of congestion avoidance by adaptively minimizing the queue-loss rate and the average queue size. Simulation results obtained using NS2 establish the improved performance of LALRED over the traditional RED methods which were chosen as the benchmarks for performance comparison purposes.

Los Angeles congestion reduction demonstration (Metro ExpressLanes). National evaluation : cost benefit analysis test plan.

DOT National Transportation Integrated Search

2002-04-01

The Theory of Operations document is one of a series of deliverables documenting the National Intelligent Transportation System (ITS) Architecture developed under contract to the U.S. Department of Transportation (DOT). The Theory of Operations Docum...

Departure Queue Prediction for Strategic and Tactical Surface Scheduler Integration

NASA Technical Reports Server (NTRS)

Zelinski, Shannon; Windhorst, Robert

2016-01-01

A departure metering concept to be demonstrated at Charlotte Douglas International Airport (CLT) will integrate strategic and tactical surface scheduling components to enable the respective collaborative decision making and improved efficiency benefits these two methods of scheduling provide. This study analyzes the effect of tactical scheduling on strategic scheduler predictability. Strategic queue predictions and target gate pushback times to achieve a desired queue length are compared between fast time simulations of CLT surface operations with and without tactical scheduling. The use of variable departure rates as a strategic scheduler input was shown to substantially improve queue predictions over static departure rates. With target queue length calibration, the strategic scheduler can be tuned to produce average delays within one minute of the tactical scheduler. However, root mean square differences between strategic and tactical delays were between 12 and 15 minutes due to the different methods the strategic and tactical schedulers use to predict takeoff times and generate gate pushback clearances. This demonstrates how difficult it is for the strategic scheduler to predict tactical scheduler assigned gate delays on an individual flight basis as the tactical scheduler adjusts departure sequence to accommodate arrival interactions. Strategic/tactical scheduler compatibility may be improved by providing more arrival information to the strategic scheduler and stabilizing tactical scheduler changes to runway sequence in response to arrivals.

14 CFR 137.51 - Operation over congested areas: General.

Code of Federal Regulations, 2013 CFR

2013-01-01

... engine aircraft must be operated as follows: (i) Except for helicopters, no person may take off a loaded... effective length of the runway from any point on takeoff up to the time of attaining, with all engines operating at normal takeoff power, 105 percent of the minimum control speed with the critical engine...

14 CFR 137.51 - Operation over congested areas: General.

Code of Federal Regulations, 2014 CFR

2014-01-01

... engine aircraft must be operated as follows: (i) Except for helicopters, no person may take off a loaded... effective length of the runway from any point on takeoff up to the time of attaining, with all engines operating at normal takeoff power, 105 percent of the minimum control speed with the critical engine...

14 CFR 137.51 - Operation over congested areas: General.

Code of Federal Regulations, 2010 CFR

2010-01-01

... engine aircraft must be operated as follows: (i) Except for helicopters, no person may take off a loaded... effective length of the runway from any point on takeoff up to the time of attaining, with all engines operating at normal takeoff power, 105 percent of the minimum control speed with the critical engine...

14 CFR 137.51 - Operation over congested areas: General.

Code of Federal Regulations, 2012 CFR

2012-01-01

... engine aircraft must be operated as follows: (i) Except for helicopters, no person may take off a loaded... effective length of the runway from any point on takeoff up to the time of attaining, with all engines operating at normal takeoff power, 105 percent of the minimum control speed with the critical engine...

14 CFR 137.51 - Operation over congested areas: General.

Code of Federal Regulations, 2011 CFR

2011-01-01

... engine aircraft must be operated as follows: (i) Except for helicopters, no person may take off a loaded... effective length of the runway from any point on takeoff up to the time of attaining, with all engines operating at normal takeoff power, 105 percent of the minimum control speed with the critical engine...

Shared-use bus priority lanes on city streets : case studies in design and management

DOT National Transportation Integrated Search

2012-04-01

This report examines the policies and strategies governing the design and, especially, operations of bus lanes in major congested urban centers. It focuses on bus lanes that operate in mixed traffic conditions; the study does not examine practices co...

A synthesis of the "state-of-the-practice for advancing planning and operations integration opportunities within transportation agencies" : [summary].

DOT National Transportation Integrated Search

2014-12-01

Federal law requires that metropolitan transportation plans include operations and : management strategies to improve the performance of existing roads, relieve congestion, : and maximize the safety and mobility of people and cargo. Transportation op...

Turbulence Climatology at Dallas/Ft.Worth (DFW) Airport: Implications for a Departure Wake Vortex Spacing System

NASA Technical Reports Server (NTRS)

Perras, G. H.; Dasey, T. J.

2000-01-01

Potential adaptive wake vortex spacing systems may need to rely on wake vortex decay rather than wake vortex transport in reducing wake separations. A wake vortex takeoff-spacing system in particular will need to rely on wake decay. Ambient turbulence is the primary influence on wake decay away from the ground. This study evaluated 18 months of ambient turbulence measurements at Dallas/Ft. Worth (DFW) Airport. The measurements show minor variation in the turbulence levels at various times of the year or times of the day for time periods when a departure system could be used. Arrival system operation was also examined, and a slightly lower overall turbulence level was found as compared to departure system benefit periods. The Sarpkaya model, a validated model of wake vortex behavior, was applied to various turbulence levels and compared to the DFW turbulence statistics. The results show that wake vortices from heavy aircraft on takeoff should dissipate within one minute for the majority of the time and will rarely last two minutes. These results will need to be verified by wake vortex measurements on departure.

Integration of Weather Data into Airspace and Traffic Operations Simulation (ATOS) for Trajectory- Based Operations Research

NASA Technical Reports Server (NTRS)

Peters, Mark; Boisvert, Ben; Escala, Diego

2009-01-01

Explicit integration of aviation weather forecasts with the National Airspace System (NAS) structure is needed to improve the development and execution of operationally effective weather impact mitigation plans and has become increasingly important due to NAS congestion and associated increases in delay. This article considers several contemporary weather-air traffic management (ATM) integration applications: the use of probabilistic forecasts of visibility at San Francisco, the Route Availability Planning Tool to facilitate departures from the New York airports during thunderstorms, the estimation of en route capacity in convective weather, and the application of mixed-integer optimization techniques to air traffic management when the en route and terminal capacities are varying with time because of convective weather impacts. Our operational experience at San Francisco and New York coupled with very promising initial results of traffic flow optimizations suggests that weather-ATM integrated systems warrant significant research and development investment. However, they will need to be refined through rapid prototyping at facilities with supportive operational users We have discussed key elements of an emerging aviation weather research area: the explicit integration of aviation weather forecasts with NAS structure to improve the effectiveness and timeliness of weather impact mitigation plans. Our insights are based on operational experiences with Lincoln Laboratory-developed integrated weather sensing and processing systems, and derivative early prototypes of explicit ATM decision support tools such as the RAPT in New York City. The technical components of this effort involve improving meteorological forecast skill, tailoring the forecast outputs to the problem of estimating airspace impacts, developing models to quantify airspace impacts, and prototyping automated tools that assist in the development of objective broad-area ATM strategies, given probabilistic weather forecasts. Lincoln Laboratory studies and prototype demonstrations in this area are helping to define the weather-assimilated decision-making system that is envisioned as a key capability for the multi-agency Next Generation Air Transportation System [1]. The Laboratory's work in this area has involved continuing, operations-based evolution of both weather forecasts and models for weather impacts on the NAS. Our experience has been that the development of usable ATM technologies that address weather impacts must proceed via rapid prototyping at facilities whose users are highly motivated to participate in system evolution.

30 CFR 250.432 - How do I obtain a departure to diverter design and installation requirements?

Code of Federal Regulations, 2011 CFR

2011-07-01

... MANAGEMENT, REGULATION, AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Diverter System Requirements § 250... diameter of at least 8 inches. (d) Use a single diverter line for floating drilling operations on a...

30 CFR 250.432 - How do I obtain a departure to diverter design and installation requirements?

Code of Federal Regulations, 2013 CFR

2013-07-01

... ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Diverter System Requirements § 250.432 How do I obtain a... least 8 inches. (d) Use a single diverter line for floating drilling operations on a dynamically...

30 CFR 250.432 - How do I obtain a departure to diverter design and installation requirements?

Code of Federal Regulations, 2014 CFR

2014-07-01

... ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Diverter System Requirements § 250.432 How do I obtain a... least 8 inches. (d) Use a single diverter line for floating drilling operations on a dynamically...

30 CFR 250.432 - How do I obtain a departure to diverter design and installation requirements?

Code of Federal Regulations, 2012 CFR

2012-07-01

... ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Diverter System Requirements § 250.432 How do I obtain a... least 8 inches. (d) Use a single diverter line for floating drilling operations on a dynamically...

Economic analysis for transmission operation and planning

NASA Astrophysics Data System (ADS)

Zhou, Qun

2011-12-01

Restructuring of the electric power industry has caused dramatic changes in the use of transmission system. The increasing congestion conditions as well as the necessity of integrating renewable energy introduce new challenges and uncertainties to transmission operation and planning. Accurate short-term congestion forecasting facilitates market traders in bidding and trading activities. Cost sharing and recovery issue is a major impediment for long-term transmission investment to integrate renewable energy. In this research, a new short-term forecasting algorithm is proposed for predicting congestion, LMPs, and other power system variables based on the concept of system patterns. The advantage of this algorithm relative to standard statistical forecasting methods is that structural aspects underlying power market operations are exploited to reduce the forecasting error. The advantage relative to previously proposed structural forecasting methods is that data requirements are substantially reduced. Forecasting results based on a NYISO case study demonstrate the feasibility and accuracy of the proposed algorithm. Moreover, a negotiation methodology is developed to guide transmission investment for integrating renewable energy. Built on Nash Bargaining theory, the negotiation of investment plans and payment rate can proceed between renewable generation and transmission companies for cost sharing and recovery. The proposed approach is applied to Garver's six bus system. The numerical results demonstrate fairness and efficiency of the approach, and hence can be used as guidelines for renewable energy investors. The results also shed light on policy-making of renewable energy subsidies.

Reynolds number scaling of the influence of boundary layers on the global behavior of laboratory quasi-Keplerian flows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edlund, E. M.; Ji, H.

2015-10-06

Here, we present fluid velocity measurements in a modified Taylor-Couette device operated in the quasi-Keplerian regime, where it is observed that nearly ideal flows exhibit self-similarity under scaling of the Reynolds number. In contrast, nonideal flows show progressive departure from ideal Couette as the Reynolds number is increased. We present a model that describes the observed departures from ideal Couette rotation as a function of the fluxes of angular momentum across the boundaries, capturing the dependence on Reynolds number and boundary conditions.

Reynolds number scaling of the influence of boundary layers on the global behavior of laboratory quasi-Keplerian flows.

PubMed

Edlund, E M; Ji, H

2015-10-01

We present fluid velocity measurements in a modified Taylor-Couette device operated in the quasi-Keplerian regime, where it is observed that nearly ideal flows exhibit self-similarity under scaling of the Reynolds number. In contrast, nonideal flows show progressive departure from ideal Couette as the Reynolds number is increased. We present a model that describes the observed departures from ideal Couette rotation as a function of the fluxes of angular momentum across the boundaries, capturing the dependence on Reynolds number and boundary conditions.

Integrated arterial and freeway operation control strategies for IVHS advanced traffic management systems : research report

DOT National Transportation Integrated Search

1998-09-01

The main focus of this study is congestion, primarily that occurring on freeway corridors in metropolitan areas. Lack of coordination in the operation of various components of the system is often a major source of inefficiency, : resulting in greater...

78 FR 28276 - Operating Limitations at John F. Kennedy International Airport

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-14

... Limitations at John F. Kennedy International Airport AGENCY: Federal Aviation Administration (FAA), DOT... duration of the Order. The reasons for issuing the Order have not changed appreciably since it was implemented. Without the operational limitations imposed by this Order, the FAA expects severe congestion...

78 FR 28280 - Operating Limitations at Newark Liberty International Airport

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-14

... Limitations at Newark Liberty International Airport AGENCY: Federal Aviation Administration (FAA), DOT. ACTION... duration of the Order. The reasons for issuing the Order have not changed appreciably since it was implemented. Without the operational limitations imposed by this Order, the FAA expects severe congestion...

Effects of mental workload on physiological and subjective responses during traffic density monitoring: A field study.

PubMed

Fallahi, Majid; Motamedzade, Majid; Heidarimoghadam, Rashid; Soltanian, Ali Reza; Miyake, Shinji

2016-01-01

This study evaluated operators' mental workload while monitoring traffic density in a city traffic control center. To determine the mental workload, physiological signals (ECG, EMG) were recorded and the NASA-Task Load Index (TLX) was administered for 16 operators. The results showed that the operators experienced a larger mental workload during high traffic density than during low traffic density. The traffic control center stressors caused changes in heart rate variability features and EMG amplitude, although the average workload score was significantly higher in HTD conditions than in LTD conditions. The findings indicated that increasing traffic congestion had a significant effect on HR, RMSSD, SDNN, LF/HF ratio, and EMG amplitude. The results suggested that when operators' workload increases, their mental fatigue and stress level increase and their mental health deteriorate. Therefore, it maybe necessary to implement an ergonomic program to manage mental health. Furthermore, by evaluating mental workload, the traffic control center director can organize the center's traffic congestion operators to sustain the appropriate mental workload and improve traffic control management. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Investigation, Modeling, and Analysis of Integrated Metroplex Arrival and Departure Coordination Concepts

NASA Technical Reports Server (NTRS)

Clarke, John-Paul B.; Brooks, James; McClain, Evan; Paladhi, Anwesha Roy; Li, Leihong; Schleicher, David; Saraf, Aditya; Timar, Sebastian; Crisp, Don; Bertino, Jason;

Airspace Technology Demonstration 2 (ATD-2) Technology Description Document (TDD)

NASA Technical Reports Server (NTRS)

Ging, Andrew; Engelland, Shawn; Capps, Al; Eshow, Michelle; Jung, Yoon; Sharma, Shivanjli; Talebi, Ehsan; Downs, Michael; Freedman, Cynthia; Ngo, Tyler;

76 FR 18620 - Operating Limitations at John F. Kennedy International Airport

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-04

.... Kennedy International Airport (JFK) that published on January 18, 2008, and was amended on February 14... rulemaking. Background Until recently, most operations at JFK took place during relatively pronounced arrival... limited the number of arrivals and departures at JFK during the peak afternoon demand period through the...

Phase II : operational and safety-based analyses of varied toll lane configurations.

DOT National Transportation Integrated Search

2016-08-01

The Puerto Rico Dynamic Toll Lane (DTL) is a 6.44 mi (10.4 km) reversible facility within a stretch of freeway PR-22 that operates a congestion pricing system; the first of its kind in the Commonwealth of Puerto Rico. This managed lane system is shar...

MeTriS : Metropolitan Transportation Information System : applying space based technologies for freight congestion mitigation.

DOT National Transportation Integrated Search

2010-06-01

Port operations are at the heart of some of the most dynamic metropolitan centers in the : world: London, New York, Los Angeles, Singapore and Hong Kong, to name a few. Ports are : critical cogs in national and local economies, but their operations a...

Shared-use bus priority lanes on city streets : case studies in design and management [research brief].

DOT National Transportation Integrated Search

2012-04-01

This study examines the design and operations of bus lanes in major congested urban centers. It focuses on shared-use bus lanes that operate in mixed traffic conditions. : Study Methods : The key questions addressed are: : 1. How do the many public a...

Characterization of Days Based On Analysis of National Airspace System Performance Metrics

NASA Technical Reports Server (NTRS)

Chatterji, Gano B.; Musaffar, Bassam; Meyn, Larry A.; Quon, Leighton K.

2006-01-01

Days of operations in the National Airspace System can be described in term of traffic demand, runway conditions, equipment outages, and surface and enroute weather conditions. These causes manifest themselves in terms of departure delays, arrival delays, enroute delays and traffic flow management delays, Traffic flow management initiatives such as, ground stops, ground delay programs, miles-in-trail restrictions, rerouting and airborne holding are imposed to balance the air traffic demand with respect to the available capacity, In order to maintain operational efficiency of the National Airspace System, the Federal Aviation Administration (FAA) maintains delay sad other statistics in the Air Traffic Operations Network (OPSNET) and the Aviation System Performance Metrics (ASPM) databases. OPSNET data includes reportable delays of fifteen minutes ox more experienced by Instrument Flight Rule (IFR) flights. Numbers of aircraft affected by departure delays, enroute delays, arrival delays and traffic flow delays are recorded in the OPSNET data. ASPM data consist of number of actual departures, number of canceled departures, percentage of on time departures, percentage of on time gate arrivals, taxi-out delays. taxi-in delays, gate delays, arrival delays and block delays. Surface conditions at the major U.S. airports are classified in terms of Instrument Meteorological Condition (IMC) and Visual Meteorological Condition (VMC) as a function of the time of the day in the ASPM data. The main objective of this paper is to use OPSNET and ASPM data to classify the days in the datasets into few distinct groups, where each group is separated from the other groups in terms of a distance metric. The motivations for classifying the days are two-fold, 1) to enable selection of days of traffic with particular operational characteristics for concept evaluation using system-wide simulation systems such as the National Aeronautics and Space Administration's Airspace Concepts Evaluation Tool (ACES) and 2) to enable evaluation of a given day with respect to the characteristics of the classified groups. The first part of the paper is devoted to the analysis of major trends seen in the OPSNET and ASPM data. The second part of the paper is devoted to describing features or measures derived from the OPSNET and ASPM data that are suitable for characterizing days, and the classification algorithm used for grouping the days. Finally, the method for evaluating the characteristics of a given day with respect to the properties of the groups is described.

14 CFR 61.101 - Recreational pilot privileges and limitations.

Code of Federal Regulations, 2014 CFR

2014-01-01

..., communications, navigation system and facilities, and radar services. (ii) Operations at airports with an... person's possession in the aircraft, that permits flight within 50 nautical miles from the departure...

14 CFR 61.101 - Recreational pilot privileges and limitations.

Code of Federal Regulations, 2012 CFR

2012-01-01

..., communications, navigation system and facilities, and radar services. (ii) Operations at airports with an... person's possession in the aircraft, that permits flight within 50 nautical miles from the departure...

14 CFR 61.101 - Recreational pilot privileges and limitations.

Code of Federal Regulations, 2013 CFR

2013-01-01

..., communications, navigation system and facilities, and radar services. (ii) Operations at airports with an... person's possession in the aircraft, that permits flight within 50 nautical miles from the departure...

ITS opportunities in port operations

DOT National Transportation Integrated Search

1998-08-19

Intelligent Transportation Systems (ITS) reduce congestion and increase safety and efficiency on our streets, highways, railroads, and airways, in an attempt to create an intermodal system which facilitates passenger and cargo transfer. Considerable ...

Information Requirements for Supervisory Air Traffic Controllers in Support of a Wake Vortex Departure System

NASA Technical Reports Server (NTRS)

Lohr, Gary W.; Williams, Daniel M.; Trujillo, Anna C.

2008-01-01

Closely Space Parallel Runway (CSPR) configurations are capacity limited for departures due to the requirement to apply wake vortex separation standards from traffic departing on the adjacent parallel runway. To mitigate the effects of this constraint, a concept focusing on wind dependent departure operations has been developed, known as the Wake Turbulence Mitigation for Departures (WTMD). This concept takes advantage of the fact that crosswinds of sufficient velocity blow wakes generated by aircraft departing from the downwind runway away from the upwind runway. Consequently, under certain conditions, wake separations on the upwind runway would not be required based on wakes generated by aircraft on the downwind runway, as is currently the case. It follows that information requirements, and sources for this information, would need to be determined for airport traffic control tower (ATCT) supervisory personnel who would be charged with decisions regarding use of the procedure. To determine the information requirements, data were collected from ATCT supervisors and controller-in-charge qualified individuals at Lambert-St. Louis International Airport (STL) and George Bush Houston Intercontinental Airport (IAH). STL and IAH were chosen as data collection sites based on the implementation of a WTMD prototype system, operating in shadow mode, at these locations. The 17 total subjects (STL: 5, IAH: 12) represented a broad-base of air traffic experience. Results indicated that the following information was required to support the conduct of WTMD operations: current and forecast weather information, current and forecast traffic demand and traffic flow restrictions, and WTMD System status information and alerting. Subjects further indicated that the requisite information is currently available in the tower cab with the exception of the WTMD status and alerting. Subjects were given a demonstration of a display supporting the prototype systems and unanimously stated that the WTMD status information they felt important was represented. Overwhelmingly, subjects felt that approving, monitoring and terminating the WTMD procedure could be integrated into their supervisory workload.

Transmission dispatch and congestion management in open market systems

NASA Astrophysics Data System (ADS)

Fang, Risheng

This thesis is located in the domain of electricity supply industry restructuring. It deals with emerging issues, whose understanding is essential to advancing knowledge of open access transmission theory and proceeds to develop approaches for solving the transmission dispatch and congestion management problem. An overview of current trends and experiences in utility restructuring and the main models for restructuring, as well as the classifications of system operators, is first presented. A fully unbundled competitive electricity market model, called the bilateral/multilateral trades model, is then developed. A survey of current research in transmission dispatch and congestion management is included with discussion of transmission capacity and ancillary services. A methodology for the power dispatch problem in a structure dominated by bilateral and multilateral transmission contracts is presented. Group structures are mathematically formulated and explored and three basic types of curtailment strategies proposed for use by market participants. A more complex model is then developed, which takes into account the co-existence of bilateral and multilateral contracts with pool type dynamic supplies and demands based on bids and market clearing prices. An integrated dispatch strategy to reconcile all three types of transactions (bilateral, multilateral and pool) is then developed. Prioritization of electricity transactions and related curtailment strategies are explored and a mechanism for coordination between market participants to achieve additional economic advantages is described. A theory of security based rescheduling is presented in order to investigate the security-related aspects of operation in an unbundled and deregulated system. The impact of post-contingency corrective capability on optimal rescheduling results has been identified and the advantage of incorporating post-contingency corrective rescheduling into the objective function demonstrated. Finally, integrated congestion management procedures in real-time system operation and in forward energy markets are developed. Market price response and coordination of dispatch by the ISO are incorporated to achieve an overall strategy.

Separation of Lift-Generated Vortex Wakes Into Two Diverging Parts

NASA Technical Reports Server (NTRS)

Rossow, Vernon J.; Brown, Anthony P.

2010-01-01

As part of an ongoing study of the spreading rate of lift-generated vortex wakes, the present investigation considers possible reasons as to why segments of lift-generated wakes sometimes depart from the main part of the wake to move rapidly in either an upward or downward direction. It is assumed that deficiencies or enhancements of the lift carry over across the fuselage-shrouded wing are the driving mechanism for departures of wake-segments. The computations presented first indicate that upwardly departing wake segments that were observed and photographed could have been produced by a deficiency in lift carryover across the fuselage-shrouded part of the wing. Computations made of idealized vortex wakes indicate that upward departure of a wake segment requires a centerline reduction in the span loading of 70% or more, whether the engines are at idle or robust thrust. Similarly, it was found that downward departure of wake segments is produced when the lift over the center part of the wing is enhanced. However, it was also found that downward departures do not occur without the presence of robust engine-exhaust streams (i.e., engines must NOT be at idle). In those cases, downward departures of a wake segment occurs when the centerline value of the loading is enhanced by any amount between about 10% to 100%. Observations of condensation trails indicate that downward departure of wake segments is rare. Upward departures of wake segments appears to be more common but still rare. A study to determine the part of the aircraft that causes wake departures has not been carried out. However, even though departures of wake segments rarely occur, some aircraft do regularly shed these wake structures. If aircraft safety is to be assured to a high degree of reliability, and a solution for eliminating them is not implemented, existing guidelines for the avoidance of vortex wakes [1,3] may need to be broadened to include possible increases in wake sizes caused by vertical departures of wake segments. Further study may indicate that it is not possible to modify existing aircraft enough to prevent wake departures. Wake-avoidance guidelines must then be adjusted to provide the desired degree of safety. It appears that steps to avoid upwardly moving wake segments have already been incorporated into the avoidance procedures used for aircraft on approach to runways at the Frankfurt Airport [6,7]. The uncertainty in the prospects for compromises in flight safety caused by rapidly upwardly or downwardly moving wake segments suggest that it be specified that aircraft do not fly above or below each other during operations in the airport vicinity where aircraft are likely to be closely spaced [20].

Feasibility of lane closures using probe data.

DOT National Transportation Integrated Search

2017-04-01

To develop an adequate traffic operations management and congestion mitigation plan for every roadway : maintenance and construction project requiring lane closures, transportation agencies need accurate and : reliable estimates of traffic impacts as...

Estimating C-17 Aircrew Seasoning Given a Prediction of Flying Austerity

DTIC Science & Technology

2014-06-01

mission classification, operating organization, operating squadron, actual departure time (in Zulu ), actual arrival time (in Zulu ), and flight time in...zero. The horizontal axis is the time axis and is in Julian day units starting with January 1, 2013 and terminates at 2359 Zulu on June 30th 2013

Windows 8: What Educators Need to Know

ERIC Educational Resources Information Center

Vedder, Richard G.

2012-01-01

In October 2012, Microsoft will release the commercial version of its next operating system, presently called "Windows 8." This version represents a significant departure from the past. Microsoft wants this operating system to meet user needs regardless of physical platform (e.g., desktop, notebook, tablet, mobile phone). As part of this mission,…

76 FR 18618 - Operating Limitations at Newark Liberty International Airport

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-04

... International Airport (JFK). With a temporary schedule limit order in place, the FAA proposed a long-term rule... to implement a long-term congestion management rule at LaGuardia Airport (LGA), JFK, and EWR. The FAA... coincides with the expiration dates for the Orders limiting scheduled operations at JFK and LGA, as also...

Spot and Runway Departure Advisor

NASA Technical Reports Server (NTRS)

Jung, Yoon Chul

2013-01-01

The Spot and Runway Departure Advisor (SARDA) is a research prototype of a decision support tool for ATC tower controllers to assist in manging and controlling traffic on the surface of an airport. SARDA employs a scheduler to generate an optimal runway schedule and gate push-back - spot release sequence and schedule that improves efficiency of surface operations. The advisories for ATC tower controllers are displayed on an Electronic Flight Strip (EFS) system. The human-in-the-loop simulation of the SARDA tool was conducted for east operations of Dallas-Ft. Worth International Airport (DFW) to evaluate performance of the SARDA tool and human factors, such as situational awareness and workload. The results indicates noticeable taxi delay reduction and fuel savings by using the SARDA tool. Reduction in controller workload were also observed throughout the scenario runs. The future plan includes modeling and simulation of the ramp operations of the Charlotte International Airport, and develop a decision support tool for the ramp controllers.

Rail capacity improvement study for commuter operations.

DOT National Transportation Integrated Search

2012-11-01

The Federal Transit Administration (FTA) notes that over the last decade, commuter rail systems have experienced increased ridership that closely matches the increases in gasoline prices. FTA also identified highway congestion and environmental conce...

Safety Benefits of Access Spacing

DOT National Transportation Integrated Search

1997-01-01

The spacing of driveways and streets is an important element in roadway planning, design, and operation. Access points are the main source of accidents and congestion. Their location and spacing affects the safety and functional integrity of streets ...

78 FR 40488 - Availability of Draft Environmental Impact Statement for the Proposed Construction of a Highway...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-05

... operating conditions for vehicular and pedestrian traffic; Improve capacity of the local roadway network; Improve local mobility; reduce congestion; improve emergency response times; and Improve evacuation...

Atlanta congestion reduction demonstration. National evaluation : content analysis test plan.

DOT National Transportation Integrated Search

2000-05-30

Commercial Vehicle Information Systems and Networks (CVISN) is the collection of information systems and communication networks that support commercial vehicle operations (CVO.) The National ITS Architecture provides a technical framework that descri...

Enhancement of freeway incident traffic management and resulting benefits.

DOT National Transportation Integrated Search

2012-04-01

To improve traffic conditions on major highways plagued by non-recurrent congestion, most : highway agencies have invested their resources in two principal operational programs: incident response : and clearance, and traffic impact management. Howeve...

Incident management program for Virginia.

DOT National Transportation Integrated Search

1988-01-01

Freeways that are already operating at or near capacity are becoming more congested because of frequent incidents such as accidents, disabled vehicles, etc. In an effort to initiate an incident management program in Virginia, information from other s...

Optimal Integration of Departures and Arrivals in Terminal Airspace

NASA Technical Reports Server (NTRS)

Xue, Min; Zelinski, Shannon Jean

2013-01-01

Coordination of operations with spatially and temporally shared resources, such as route segments, fixes, and runways, improves the efficiency of terminal airspace management. Problems in this category are, in general, computationally difficult compared to conventional scheduling problems. This paper presents a fast time algorithm formulation using a non-dominated sorting genetic algorithm (NSGA). It was first applied to a test problem introduced in existing literature. An experiment with a test problem showed that new methods can solve the 20 aircraft problem in fast time with a 65% or 440 second delay reduction using shared departure fixes. In order to test its application in a more realistic and complicated problem, the NSGA algorithm was applied to a problem in LAX terminal airspace, where interactions between 28% of LAX arrivals and 10% of LAX departures are resolved by spatial separation in current operations, which may introduce unnecessary delays. In this work, three types of separations - spatial, temporal, and hybrid separations - were formulated using the new algorithm. The hybrid separation combines both temporal and spatial separations. Results showed that although temporal separation achieved less delay than spatial separation with a small uncertainty buffer, spatial separation outperformed temporal separation when the uncertainty buffer was increased. Hybrid separation introduced much less delay than both spatial and temporal approaches. For a total of 15 interacting departures and arrivals, when compared to spatial separation, the delay reduction of hybrid separation varied between 11% or 3.1 minutes and 64% or 10.7 minutes corresponding to an uncertainty buffer from 0 to 60 seconds. Furthermore, as a comparison with the NSGA algorithm, a First-Come-First-Serve based heuristic method was implemented for the hybrid separation. Experiments showed that the results from the NSGA algorithm have 9% to 42% less delay than the heuristic method with varied uncertainty buffer sizes.

The impact of high-risk drivers and benefits of limiting their driving degree of freedom.

PubMed

Habtemichael, Filmon G; de Picado-Santos, Luis

2013-11-01

The perception of drivers regarding risk-taking behaviour is widely varied. High-risk drivers are the segment of drivers who are disproportionately represented in the majority of crashes. This study examines the typologies of drivers in risk-taking behaviour, the common high-risk driving errors (speeding, close following, abrupt lane-changing and impaired driving), their safety consequences and the technological (ITS) devices for their detection and correction. Limiting the driving degree of freedom of high-risk drivers is proposed and its benefits on safety as well as traffic operations are quantified using VISSIM microscopic traffic simulation at various proportions of high-risk drivers; namely, 4%, 8% and 12%. Assessment of the safety benefits was carried out by using the technique of simulated vehicle conflicts which was validated against historic crashes, and reduction in travel time was used to quantify the operational benefits. The findings imply that limiting the freedom of high-risk drivers resulted in a reduction of crashes by 12%, 21% and 27% in congested traffic conditions; 9%, 13% and 18% in lightly congested traffic conditions as well as 9%, 10% and 17% in non-congested traffic conditions for high-risk drivers in proportions of 4%, 8% and 12% respectively. Moreover, the surrogate safety measures indicated that there was a reduction in crash severity levels. The operational benefits amounted to savings of nearly 1% in travel time for all the proportions of high-risk drivers considered. The study concluded that limiting the freedom of high-risk drivers has safety and operational benefits; though there could be social, legal and institutional concerns for its practical implementation. Copyright © 2013 Elsevier Ltd. All rights reserved.

The Effects of the Uncertainty of Departures on Multi-Center Traffic Management Advisor (TMA) Scheduling

NASA Technical Reports Server (NTRS)

Thipphavong, Jane; Landry, Steven J.

2005-01-01

The Multi-center Traffic Management Advisor (McTMA) provides a platform for regional or national traffic flow management, by allowing long-range cooperative time-based metering to constrained resources, such as airports or air traffic control center boundaries. Part of the demand for resources is made up of proposed departures, whose actual departure time is difficult to predict. For this reason, McTMA does not schedule the departures in advance, but rather relies on traffic managers to input their requested departure time. Because this happens only a short while before the aircraft's actual departure, McTMA is unable to accurately predict the amount of delay airborne aircraft will need to take in order to accommodate the departures. The proportion of demand which is made up by such proposed departures increases as the horizon over which metering occurs gets larger. This study provides an initial analysis of the severity of this problem in a 400-500 nautical mile metering horizon and discusses potential solutions to accommodate these departures. The challenge is to smoothly incorporate departures with the airborne stream while not excessively delaying the departures.' In particular, three solutions are reviewed: (1) scheduling the departures at their proposed departure time; (2) not scheduling the departures in advance; and (3) scheduling the departures at some time in the future based on an estimated error in their proposed time. The first solution is to have McTMA to automatically schedule the departures at their proposed departure times. Since the proposed departure times are indicated in their flight times in advance, this method is the simplest, but studies have shown that these proposed times are often incorrect2 The second option is the current practice, which avoids these inaccuracies by only scheduling aircraft when a confirmed prediction of departure time is obtained from the tower of the departure airport. Lastly, McTMA can schedule the departures at a predicted departure time based on statistical data of past departure time performance. It has been found that departures usually have a wheels-up time after their indicated proposed departure time, as shown in Figure 1. Hence, the departures were scheduled at a time in the future based on the mean error in proposed departure times for their airport.

78 FR 5856 - Agency Information Collection Activities: Requests for Comments; Clearance of New Approval of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-28

... (JFK), Newark Liberty International Airport (EWR), and LaGuardia Airport (LGA). The FAA also has... the FAA to allocate arrival and departure slots at JFK, EWR, and LGA. The designations resulted in... holding a slot at JFK, EWR, or LGA; by carriers operating at ORD or SFO; or by operators conducting...

Current Issues in the Design and Information Content of Instrument Approach Charts

DOT National Transportation Integrated Search

1995-03-01

This report documents an analysis and interview effort conducted to identify common operational errors made using : current Instrument Approach Plates (IAP), Standard Terminal Arrival Route (STAR) charts. Standard Instrument Departure : (SID) charts,...

Federal Aviation Administration wake turbulence program - recent highlights

DOT National Transportation Integrated Search

2012-10-01

Aircraft-generated wake turbulence has for years been a major factor in the air-traffic-control-imposed : separations between aircraft during departure, transit and arrival operations conducted at airports and air : corridors of high volume. Applied ...

Evaluation of a Tactical Surface Metering Tool for Charlotte Douglas International Airport via Human-in-the-Loop Simulation

NASA Technical Reports Server (NTRS)

Verma, Savita; Lee, Hanbong; Dulchinos, Victoria L.; Martin, Lynne; Stevens, Lindsay; Jung, Yoon; Chevalley, Eric; Jobe, Kim; Parke, Bonny

2017-01-01

NASA has been working with the FAA and aviation industry partners to develop and demonstrate new concepts and technologies that integrate arrival, departure, and surface traffic management capabilities. In March 2017, NASA conducted a human-in-the-loop (HITL) simulation for integrated surface and airspace operations, modeling Charlotte Douglas International Airport, to evaluate the operational procedures and information requirements for the tactical surface metering tool, and data exchange elements between the airline controlled ramp and ATC Tower. In this paper, we focus on the calibration of the tactical surface metering tool using various metrics measured from the HITL simulation results. Key performance metrics include gate hold times from pushback advisories, taxi-in-out times, runway throughput, and departure queue size. Subjective metrics presented in this paper include workload, situational awareness, and acceptability of the metering tool and its calibration.

Evaluation of a Tactical Surface Metering Tool for Charlotte Douglas International Airport Via Human-in-the-Loop Simulation

NASA Technical Reports Server (NTRS)

Verma, Savita; Lee, Hanbong; Martin, Lynne; Stevens, Lindsay; Jung, Yoon; Dulchinos, Victoria; Chevalley, Eric; Jobe, Kim; Parke, Bonny

2017-01-01

NASA has been working with the FAA and aviation industry partners to develop and demonstrate new concepts and technologies that integrate arrival, departure, and surface traffic management capabilities. In March 2017, NASA conducted a human-in-the-loop (HITL) simulation for integrated surface and airspace operations, modeling Charlotte Douglas International Airport, to evaluate the operational procedures and information requirements for the tactical surface metering tool, and data exchange elements between the airline controlled ramp and ATC Tower. In this paper, we focus on the calibration of the tactical surface metering tool using various metrics measured from the HITL simulation results. Key performance metrics include gate hold times from pushback advisories, taxi-in/out times, runway throughput, and departure queue size. Subjective metrics presented in this paper include workload, situational awareness, and acceptability of the metering tool and its calibration

Design and scope of impact of auxiliary lanes : technical report.

DOT National Transportation Integrated Search

2014-06-01

For decades, Texas Department of Transportation districts have constructed auxiliary lanes to support interchange : ramp operations and to resolve congestion proximate to freeway entrance and exit ramps. While auxiliary lanes are : built throughout T...

Addressing MAP-21 freight objectives using GPS data.

DOT National Transportation Integrated Search

2016-12-01

Freight planning and operation perspectives of Moving Ahead for Progress in the 21st Century Act (MAP-21) includes development of a national freight plan to address freight congestion bottlenecks, connectivity enhancement of major intermodal centers,...

Freight tricycle operations in New York City.

DOT National Transportation Integrated Search

2014-10-01

As cities become more congested and increasingly focused on sustainability, cargo cycles offer a potential alternative to motorized vehicles for local and : last : - : mile goods delivery. However, few studies have examined this mode in the North Ame...

Development of Mission Enabling Infrastructure — Cislunar Autonomous Positioning System (CAPS)

NASA Astrophysics Data System (ADS)

Cheetham, B. W.

2017-10-01

Advanced Space, LLC is developing the Cislunar Autonomous Positioning System (CAPS) which would provide a scalable and evolvable architecture for navigation to reduce ground congestion and improve operations for missions throughout cislunar space.

Sharing resources, coordinating response : deploying and operating incident management systems

DOT National Transportation Integrated Search

1999-01-05

This brochure describes how cost-effective incident management technologies can be useful in handling traffic congestion. Embedded sensors, closed circuit television cameras, and variable message signs are examples of existing technologies that can b...

Simulation and analysis of three congested weigh stations using Westa

DOT National Transportation Integrated Search

2001-01-01

A user-friendly model for personal computers, "Vehicle/Highway Performance Predictor," was developed to estimate fuel consumption and exhaust emissions related to modes of vehicle operations on highways of various configurations and traffic controls ...

Effects of operating practices on commercial driver alertness

DOT National Transportation Integrated Search

2011-08-01

This report presents the test plan for collecting and analyzing data dealing with travel demand management (TDM) activities for the Atlanta Congestion Reduction Demonstration (CRD) under the United States Department of Transportation (U.S. DOT) Urban...

Auctionable fixed transmission rights for congestion management

NASA Astrophysics Data System (ADS)

Alomoush, Muwaffaq Irsheid

Electric power deregulation has proposed a major change to the regulated utility monopoly. The change manifests the main part of engineers' efforts to reshape three components of today's regulated monopoly: generation, distribution and transmission. In this open access deregulated power market, transmission network plays a major role, and transmission congestion is a major problem that requires further consideration especially when inter-zonal/intra-zonal scheme is implemented. Declaring that engineering studies and experience are the criteria to define zonal boundaries or defining a zone based on the fact that a zone is a densely interconnected area (lake) and paths connecting these densely interconnected areas are inter-zonal lines will render insufficient and fuzzy definitions. Moreover, a congestion problem formulation should take into consideration interactions between intra-zonal and inter-zonal flows and their effects on power systems. In this thesis, we introduce a procedure for minimizing the number of adjustments of preferred schedules to alleviate congestion and apply control schemes to minimize interactions between zones. In addition, we give the zone definition a certain criterion based on the Locational Marginal Price (LMP). This concept will be used to define congestion zonal boundaries and to decide whether any zone should be merged with another zone or split into new zones. The thesis presents a unified scheme that combines zonal and FTR schemes to manage congestion. This combined scheme is utilized with LMPs to define zonal boundaries more appropriately. The presented scheme gains the best features of the FTR scheme, which are providing financial certainty, maximizing the efficient use of the system and making users pay for the actual use of congested paths. LMPs may give an indication of the impact of wheeling transactions, and calculations of and comparisons of LMPs with and without wheeling transactions should be adequate criteria to approve the transaction by the ISO, take a decision to expand the existing system, or retain the original structure of the system. Also, the thesis investigates the impact of wheeling transactions on congestion management, where we present a generalized mathematical model for the Fixed Transmission Right (FTR) auction. The auction guarantees FTR availability to all participants on a non-discriminatory basis, in which system users are permitted to buy, sell and trade FTRs through an auction. When FTRs are utilized with LMPs, they increase the efficient use of the transmission system and let a transmission customer gain advantageous features such as acquiring a mechanism to offset the extra cost due to congestion charges, providing financial and operational certainty and making system users pay for the actual use of the congested paths. The thesis also highlighted FTR trading in secondary markets to self-arrange access across different paths, create long-term transmission rights and provide more commercial certainty.

Spatial Analysis of Traffic and Routing Path Methods for Tsunami Evacuation

NASA Astrophysics Data System (ADS)

Fakhrurrozi, A.; Sari, A. M.

2018-02-01

Tsunami disaster occurred relatively very fast. Thus, it has a very large-scale impact on both non-material and material aspects. Community evacuation caused mass panic, crowds, and traffic congestion. A further research in spatial based modelling, traffic engineering and splitting zone evacuation simulation is very crucial as an effort to reduce higher losses. This topic covers some information from the previous research. Complex parameters include route selection, destination selection, the spontaneous timing of both the departure of the source and the arrival time to destination and other aspects of the result parameter in various methods. The simulation process and its results, traffic modelling, and routing analysis emphasized discussion which is the closest to real conditions in the tsunami evacuation process. The method that we should highlight is Clearance Time Estimate based on Location Priority in which the computation result is superior to others despite many drawbacks. The study is expected to have input to improve and invent a new method that will be a part of decision support systems for disaster risk reduction of tsunamis disaster.

The aerial relay system: An energy-efficient solution to the airport congestion problem

NASA Technical Reports Server (NTRS)

Kyser, A. C.

1980-01-01

The ability to transfer airline passengers between aircraft in flight, if adequately developed and integrated into the national air transportation system, could provide significant improvements in transportation-system performance, in terms of airport congestion, fuel consumption, and passenger service. The proposed Aerial Relay System concept, which was developed as a means of exploiting inflight transfer, makes use of large 'cruise liner' aircraft which fly continuously along their routes, docking periodically with short-haul feeder aircraft for exchange of payloads. Preliminary vehicle designs for a representative system are described and the operational feasibility of the concept for the United States in the 1990's is discussed.

Taxi-Out Time Prediction for Departures at Charlotte Airport Using Machine Learning Techniques

NASA Technical Reports Server (NTRS)

Lee, Hanbong; Malik, Waqar; Jung, Yoon C.

2016-01-01

Predicting the taxi-out times of departures accurately is important for improving airport efficiency and takeoff time predictability. In this paper, we attempt to apply machine learning techniques to actual traffic data at Charlotte Douglas International Airport for taxi-out time prediction. To find the key factors affecting aircraft taxi times, surface surveillance data is first analyzed. From this data analysis, several variables, including terminal concourse, spot, runway, departure fix and weight class, are selected for taxi time prediction. Then, various machine learning methods such as linear regression, support vector machines, k-nearest neighbors, random forest, and neural networks model are applied to actual flight data. Different traffic flow and weather conditions at Charlotte airport are also taken into account for more accurate prediction. The taxi-out time prediction results show that linear regression and random forest techniques can provide the most accurate prediction in terms of root-mean-square errors. We also discuss the operational complexity and uncertainties that make it difficult to predict the taxi times accurately.

Optimization of Airport Surface Traffic: A Case-Study of Incheon International Airport

NASA Technical Reports Server (NTRS)

Eun, Yeonju; Jeon, Daekeun; Lee, Hanbong; Jung, Yoon C.; Zhu, Zhifan; Jeong, Myeongsook; Kim, Hyounkong; Oh, Eunmi; Hong, Sungkwon

2017-01-01

This study aims to develop a controllers decision support tool for departure and surface management of ICN. Airport surface traffic optimization for Incheon International Airport (ICN) in South Korea was studied based on the operational characteristics of ICN and airspace of Korea. For surface traffic optimization, a multiple runway scheduling problem and a taxi scheduling problem were formulated into two Mixed Integer Linear Programming (MILP) optimization models. The Miles-In-Trail (MIT) separation constraint at the departure fix shared by the departure flights from multiple runways and the runway crossing constraints due to the taxi route configuration specific to ICN were incorporated into the runway scheduling and taxiway scheduling problems, respectively. Since the MILP-based optimization model for the multiple runway scheduling problem may be computationally intensive, computation times and delay costs of different solving methods were compared for a practical implementation. This research was a collaboration between Korea Aerospace Research Institute (KARI) and National Aeronautics and Space Administration (NASA).

Optimization of Airport Surface Traffic: A Case-Study of Incheon International Airport

NASA Technical Reports Server (NTRS)

Eun, Yeonju; Jeon, Daekeun; Lee, Hanbong; Jung, Yoon Chul; Zhu, Zhifan; Jeong, Myeong-Sook; Kim, Hyoun Kyoung; Oh, Eunmi; Hong, Sungkwon

2017-01-01

This study aims to develop a controllers' decision support tool for departure and surface management of ICN. Airport surface traffic optimization for Incheon International Airport (ICN) in South Korea was studied based on the operational characteristics of ICN and airspace of Korea. For surface traffic optimization, a multiple runway scheduling problem and a taxi scheduling problem were formulated into two Mixed Integer Linear Programming (MILP) optimization models. The Miles-In-Trail (MIT) separation constraint at the departure fix shared by the departure flights from multiple runways and the runway crossing constraints due to the taxi route configuration specific to ICN were incorporated into the runway scheduling and taxiway scheduling problems, respectively. Since the MILP-based optimization model for the multiple runway scheduling problem may be computationally intensive, computation times and delay costs of different solving methods were compared for a practical implementation. This research was a collaboration between Korea Aerospace Research Institute (KARI) and National Aeronautics and Space Administration (NASA).

Congestion Pricing for Aircraft Pushback Slot Allocation

PubMed Central

Zhang, Yaping

2017-01-01

In order to optimize aircraft pushback management during rush hour, aircraft pushback slot allocation based on congestion pricing is explored while considering monetary compensation based on the quality of the surface operations. First, the concept of the “external cost of surface congestion” is proposed, and a quantitative study on the external cost is performed. Then, an aircraft pushback slot allocation model for minimizing the total surface cost is established. An improved discrete differential evolution algorithm is also designed. Finally, a simulation is performed on Xinzheng International Airport using the proposed model. By comparing the pushback slot control strategy based on congestion pricing with other strategies, the advantages of the proposed model and algorithm are highlighted. In addition to reducing delays and optimizing the delay distribution, the model and algorithm are better suited for use for actual aircraft pushback management during rush hour. Further, it is also observed they do not result in significant increases in the surface cost. These results confirm the effectiveness and suitability of the proposed model and algorithm. PMID:28114429

Curbing gridlock: Peak-period fees to relieve traffic congestion. Volume 2. Commissioned papers. Special report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1994-01-01

;Contents: Volume 2: Commissioned Papers: Congestion Trends in Metropolitan Areas; Alternative Methods for Measuring Congestion Levels; Potential of Congestion Pricing in the Metropolitan Washington Region; Transportation Pricing and Travel Behavior; Peak Pricing Strategies in Transportation, Utilities, and Telecommunications: Lessons for Road Pricing; Cashing Out Employer-Paid Parking: A Precedent for Congestion Pricing; The New York Region: First in Tolls, Last in Road Pricing; Pricing Urban Roadways: Administrative and Institutional Issues; Equity and Fairness Considerations of Congestion Pricing; The Politics of Congestion Pricing; Institutional and Political Challenges in Implementing Congestion Pricing: Case Study of the San Francisco Bay Area; How Congestion Pricingmore » Came to Be Proposed in the San Diego Region: A Case History; Urban Transportation Congestion Pricing: Effects on Urban Form; Congestion Pricing and Motor Vehicle Emissions: An Initial Review; Private Toll Roads: Acceptability of Congestion Pricing in Southern California; Potential of Next-Generation Technology; Electronic Toll Collection Systems; and Impacts of Congestion Pricing on Transit and Carpool Demand and Supply.« less

40 CFR 93.153 - Applicability.

Code of Federal Regulations, 2011 CFR

2011-07-01

... control activities and adopting approach, departure, and enroute procedures for aircraft operations above... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Applicability. 93.153 Section 93.153 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) DETERMINING...

Traffic congestion and reliability : trends and advanced strategies for congestion mitigation.

DOT National Transportation Integrated Search

2005-09-01

The report Traffic Congestion and Reliability: Trends and Advanced Strategies for : Congestion Mitigation provides a snapshot of congestion in the United States by : summarizing recent trends in congestion, highlighting the role of travel time : reli...

Wind power development in the United States: Effects of policies and electricity transmission congestion

NASA Astrophysics Data System (ADS)

Hitaj, Claudia

In this dissertation, I analyze the drivers of wind power development in the United States as well as the relationship between renewable power plant location and transmission congestion and emissions levels. I first examine the role of government renewable energy incentives and access to the electricity grid on investment in wind power plants across counties from 1998-2007. The results indicate that the federal production tax credit, state-level sales tax credit and production incentives play an important role in promoting wind power. In addition, higher wind power penetration levels can be achieved by bringing more parts of the electricity transmission grid under independent system operator regulation. I conclude that state and federal government policies play a significant role in wind power development both by providing financial support and by improving physical and procedural access to the electricity grid. Second, I examine the effect of renewable power plant location on electricity transmission congestion levels and system-wide emissions levels in a theoretical model and a simulation study. A new renewable plant takes the effect of congestion on its own output into account, but ignores the effect of its marginal contribution to congestion on output from existing plants, which results in curtailment of renewable power. Though pricing congestion removes the externality and reduces curtailment, I find that in the absence of a price on emissions, pricing congestion may in some cases actually increase system-wide emissions. The final part of my dissertation deals with an econometric issue that emerged from the empirical analysis of the drivers of wind power. I study the effect of the degree of censoring on random-effects Tobit estimates in finite sample with a particular focus on severe censoring, when the percentage of uncensored observations reaches 1 to 5 percent. The results show that the Tobit model performs well even at 5 percent uncensored observations with the bias in the Tobit estimates remaining at or below 5 percent. Under severe censoring (1 percent uncensored observations), large biases appear in the estimated standard errors and marginal effects. These are generally reduced as the sample size increases in both N and T.

Using microsimulation to evaluate the effects of advanced vehicle technologies on congestion.

DOT National Transportation Integrated Search

2011-06-30

Advanced driver assistance technologies are continuously being developed to enhance traffic : safety. Evaluations of such technologies typically focus on safety and there has been limited : research on the impacts of such technologies on traffic oper...

Briefing paper : toward a best practice model for managed lanes in Texas.

DOT National Transportation Integrated Search

2013-09-01

Over the past two decades, agencies : have increasingly implemented managed : lanes (MLs) to mitigate growing urban traffic : congestion in the United States. Multiple operating : projects : representing a combination : of HOV-to-HOT conversions a...

Ramp metering : procedure manual.

DOT National Transportation Integrated Search

2002-11-01

Ramp metering is a traffic management tool used to increase the efficiency and safety of the : traffic operations on freeways. It is one of the most cost effective ways of managing traffic flow. : It improves traffic flow on congested freeways and of...

77 FR 60168 - Environmental Impact Statement: San Joaquin and Stanislaus Counties, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-02

... (3.5 miles) in length. The project was anticipated to improve traffic safety and operations by reducing congestion and accidents. Since the NOI to prepare an EIS was published in the Federal Register on...

The use of weather data to predict non-recurring traffic congestion

DOT National Transportation Integrated Search

2006-08-01

This project will demonstrate the quantitative relationship between weather patterns and surface traffic conditions. The aviation and maritime industries use weather measurements and predictions as a normal part of operations, and this can be extende...

Traffic control for high occupancy vehicle facilities in Virginia.

DOT National Transportation Integrated Search

1998-04-01

High occupancy vehicle (HOV) facilities are an important tool in relieving the congestion that continues to build on many urban roadways. By moving more people in fewer vehicles, the existing infrastructure can be used more efficiently. Operating HOV...

Evaluating transportation systems management & operations (TSM&O) benefits to alternative intersection treatments : [summary].

DOT National Transportation Integrated Search

2015-12-01

The Florida Department of Transportation (FDOT) has set a goal to optimize existing : infrastructure to improve safety, capacity, and reliability while reducing congestion and delays. : FDOT is pursuing this goal through Transportation Systems Manage...

A Subjective Assessment of Alternative Mission Architecture Operations Concepts for the Human Exploration of Mars at NASA Using a Three-Dimensional Multi-Criteria Decision Making Model

NASA Technical Reports Server (NTRS)

Tavana, Madjid

2003-01-01

The primary driver for developing missions to send humans to other planets is to generate significant scientific return. NASA plans human planetary explorations with an acceptable level of risk consistent with other manned operations. Space exploration risks can not be completely eliminated. Therefore, an acceptable level of cost, technical, safety, schedule, and political risks and benefits must be established for exploratory missions. This study uses a three-dimensional multi-criteria decision making model to identify the risks and benefits associated with three alternative mission architecture operations concepts for the human exploration of Mars identified by the Mission Operations Directorate at Johnson Space Center. The three alternatives considered in this study include split, combo lander, and dual scenarios. The model considers the seven phases of the mission including: 1) Earth Vicinity/Departure; 2) Mars Transfer; 3) Mars Arrival; 4) Planetary Surface; 5) Mars Vicinity/Departure; 6) Earth Transfer; and 7) Earth Arrival. Analytic Hierarchy Process (AHP) and subjective probability estimation are used to captures the experts belief concerning the risks and benefits of the three alternative scenarios through a series of sequential, rational, and analytical processes.

Enabling Civilian Low-Altitude Airspace and Unmanned Aerial System (UAS) Operations

NASA Technical Reports Server (NTRS)

Kopardekar, Parimal

2014-01-01

UAS operations will be safer if a UTM system is available to support the functions associated with Airspace management and geo-fencing (reduce risk of accidents, impact to other operations, and community concerns); Weather and severe wind integration (avoid severe weather areas based on prediction); Predict and manage congestion (mission safety);Terrain and man-made objects database and avoidance; Maintain safe separation (mission safety and assurance of other assets); Allow only authenticated operations (avoid unauthorized airspace use).

Lunar Surface Architecture Utilization and Logistics Support Assessment

NASA Astrophysics Data System (ADS)

Bienhoff, Dallas; Findiesen, William; Bayer, Martin; Born, Andrew; McCormick, David

2008-01-01

Crew and equipment utilization and logistics support needs for the point of departure lunar outpost as presented by the NASA Lunar Architecture Team (LAT) and alternative surface architectures were assessed for the first ten years of operation. The lunar surface architectures were evaluated and manifests created for each mission. Distances between Lunar Surface Access Module (LSAM) landing sites and emplacement locations were estimated. Physical characteristics were assigned to each surface element and operational characteristics were assigned to each surface mobility element. Stochastic analysis was conducted to assess probable times to deploy surface elements, conduct exploration excursions, and perform defined crew activities. Crew time is divided into Outpost-related, exploration and science, overhead, and personal activities. Outpost-related time includes element deployment, EVA maintenance, IVA maintenance, and logistics resupply. Exploration and science activities include mapping, geological surveys, science experiment deployment, sample analysis and categorizing, and physiological and biological tests in the lunar environment. Personal activities include sleeping, eating, hygiene, exercising, and time off. Overhead activities include precursor or close-out tasks that must be accomplished but don't fit into the other three categories such as: suit donning and doffing, airlock cycle time, suit cleaning, suit maintenance, post-landing safing actions, and pre-departure preparations. Equipment usage time, spares, maintenance actions, and Outpost consumables are also estimated to provide input into logistics support planning. Results are normalized relative to the NASA LAT point of departure lunar surface architecture.

Novel Biomarkers of Arterial and Venous Ischemia in Microvascular Flaps

PubMed Central

Nguyen, Gerard K.; Monahan, John F. W.; Davis, Gabrielle B.; Lee, Yong Suk; Ragina, Neli P.; Wang, Charles; Zhou, Zhao Y.; Hong, Young Kwon; Spivak, Ryan M.; Wong, Alex K.

2013-01-01

The field of reconstructive microsurgery is experiencing tremendous growth, as evidenced by recent advances in face and hand transplantation, lower limb salvage after trauma, and breast reconstruction. Common to all of these procedures is the creation of a nutrient vascular supply by microsurgical anastomosis between a single artery and vein. Complications related to occluded arterial inflow and obstructed venous outflow are not uncommon, and can result in irreversible tissue injury, necrosis, and flap loss. At times, these complications are challenging to clinically determine. Since early intervention with return to the operating room to re-establish arterial inflow or venous outflow is key to flap salvage, the accurate diagnosis of early stage complications is essential. To date, there are no biochemical markers or serum assays that can predict these complications. In this study, we utilized a rat model of flap ischemia in order to identify the transcriptional signatures of venous congestion and arterial ischemia. We found that the critical ischemia time for the superficial inferior epigastric fasciocutaneus flap was four hours and therefore performed detailed analyses at this time point. Histolgical analysis confirmed significant differences between arterial and venous ischemia. The transcriptome of ischemic, congested, and control flap tissues was deciphered by performing Affymetrix microarray analysis and verified by qRT-PCR. Principal component analysis revealed that arterial ischemia and venous congestion were characterized by distinct transcriptomes. Arterial ischemia and venous congestion was characterized by 408 and 1536>2-fold differentially expressed genes, respectively. qRT-PCR was used to identify five candidate genes Prol1, Muc1, Fcnb, Il1b, and Vcsa1 to serve as biomarkers for flap failure in both arterial ischemia and venous congestion. Our data suggests that Prol1 and Vcsa1 may be specific indicators of venous congestion and allow clinicians to both diagnose and successfully treat microvascular complications before irreversible tissue damage and flap loss occurs. PMID:23977093

ATD-2 IADS Metroplex Traffic Management Overview Brief

NASA Technical Reports Server (NTRS)

Engelland, Shawn

2016-01-01

ATD-2 will improve the predictability and the operational efficiency of the air traffic system in metroplex environments through the enhancement, development and integration of the nation's most advanced and sophisticated arrival, departure, and surface prediction, scheduling and management systems.

75 FR 59733 - Agency Information Collection Activities: Arrival and Departure Record (Forms I-94 and I-94W) and...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-28

... of information (a total capital/startup costs and operations and maintenance costs). The comments... Number of Respondents: 100,000. Estimated Number of Total Annual Responses: 100,000. Estimated Time per...

Map based localization to assist commercial fleet operations.

DOT National Transportation Integrated Search

2014-08-01

This report outlines key recent contributions to the state of the art in lane detection, lane departure warning, : and map-based sensor fusion algorithms. These key studies are used as a basis for a discussion about the : limitations of systems that ...

Weather-responsive traffic management : real solutions for serious traffic problems.

DOT National Transportation Integrated Search

2009-04-01

This flyer describes how weather responsive traffic management (WRTM) can prevent or mitigate the effects of weather on traffic operations and reduce congestion. The three types of WRTM described in the flyer include 1) Advisory strategies that provi...

Air traffic control : role of FAA's modernization program in reducing delays and congestion

DOT National Transportation Integrated Search

2001-05-10

The National Airspace System (NAS) is a complex collection of systems, procedures, facilities, aircraft, and people. Because these components are interconnected and interdependent, they must work together as one system to ensure safe operations. The ...

23 CFR 971.214 - Federal lands congestion management system (CMS).

Code of Federal Regulations, 2010 CFR

2010-04-01

...) Traffic operational improvements; (C) Public transportation improvements; (D) ITS technologies; and (E....214 Section 971.214 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION FEDERAL... level at which transportation system performance is no longer acceptable due to traffic interference...

Truck transportation through border ports of entry : analysis of coordination systems.

DOT National Transportation Integrated Search

2002-11-01

This report identifies shortcomings in coordination at U.S. Mexico border ports-of-entry and recommends alternatives that would improve operations and reduce congestion and delay. Based on the review of numerous previous reports and more than 100...

Multimodal system planning technique : an analytical approach to peak period operation

DOT National Transportation Integrated Search

1995-11-01

The multimodal system planning technique described in this report is an improvement of the methodology used in the Dallas System Planning Study. The technique includes a spreadsheet-based process to identify the costs of congestion, construction, and...

Guidebook on preserving the functionality of state highways in Texas.

DOT National Transportation Integrated Search

2010-05-01

The purpose of this project was to identify the sources of deterioration of state highway : functionality that occur over time and what actions can be taken to preserve, recover, and : enhance functionality. Congestion and operational problems slow t...

Supporting railroad roadway work communications with a wireless handheld computer. Volume 1 : usability for the roadway worker

DOT National Transportation Integrated Search

2004-10-01

Communications in current railroad operations rely heavily on voice communications. Radio congestion impairs roadway workers ability to communicate effectively with dispatchers at the Central Traffic Control Center and has adverse consequences for...

Supporting railroad roadway worker communications with a wireless handheld computer. Volume 1, Usability for the roadway worker.

DOT National Transportation Integrated Search

2004-10-31

Communications in current railroad operations rely heavily on voice communications. Radio congestion impairs roadway workers ability to communicate effectively with dispatchers at the Central Traffic Control Center and has adverse consequences for...

Simplified web-based decision support method for traffic management and work zone analysis.

DOT National Transportation Integrated Search

2017-01-01

Traffic congestion mitigation is one of the key challenges that transportation planners and operations engineers face when planning for construction and maintenance activities. There is a wide variety of approaches and methods that address work zone ...

Simplified web-based decision support method for traffic management and work zone analysis.

DOT National Transportation Integrated Search

2015-06-01

Traffic congestion mitigation is one of the key challenges that transportation planners and operations engineers face when : planning for construction and maintenance activities. There is a wide variety of approaches and methods that address work : z...

The geostationary orbit and developing countries

NASA Technical Reports Server (NTRS)

Medina, E. R.

1982-01-01

The geostationary orbit is becoming congested due to use by several countries throughout the world, and the request for use of this orbit is increasing. There are 188 geostationary stations in operation. An equitable distribution of stations on this orbit is requested.

Effectiveness of Bus Signal Priority : Final Report

DOT National Transportation Integrated Search

2002-01-01

Effectiveness of Bus Signal Priority (BSP) study evaluates BSP?s impact on traffic operations. The goal was to examine how different situations, such as the level of congestion, placement of bus stops, presence of express bus service, and number of t...

Minnesota : innovative choices for congestion relief.

DOT National Transportation Integrated Search

2013-01-01

All of the Minnesota UPA projects are in operation. The first project, the Transit Advantage Bus Bypass at the Highway 77/Highway 62 intersection, was implemented in December 2008. Most of the transit projects and the expansion of the existing high-o...

Analysis of Random Drop for Gateway Congestion Control

DTIC Science & Technology

1989-11-01

effective congest)on control policies. Currently No Gateway Policy is used to relieve and signal congestion, which leads to unfair service to the...early application of the policy removes the pressure of congestion relief and allows more accurate signaling of congestion. ’ To be used effectively ...prompted the need for more effective congestion control policies. Currently No Gateway Policy is used to relieve and signal congestion, which leads to

SATS HVO Concept Validation Experiment

NASA Technical Reports Server (NTRS)

Consiglio, Maria; Williams, Daniel; Murdoch, Jennifer; Adams, Catherine

2005-01-01

A human-in-the-loop simulation experiment was conducted at the NASA Langley Research Center s (LaRC) Air Traffic Operations Lab (ATOL) in an effort to comprehensively validate tools and procedures intended to enable the Small Aircraft Transportation System, Higher Volume Operations (SATS HVO) concept of operations. The SATS HVO procedures were developed to increase the rate of operations at non-towered, non-radar airports in near all-weather conditions. A key element of the design is the establishment of a volume of airspace around designated airports where pilots accept responsibility for self-separation. Flights operating at these airports, are given approach sequencing information computed by a ground based automated system. The SATS HVO validation experiment was conducted in the ATOL during the spring of 2004 in order to determine if a pilot can safely and proficiently fly an airplane while performing SATS HVO procedures. Comparative measures of flight path error, perceived workload and situation awareness were obtained for two types of scenarios. Baseline scenarios were representative of today s system utilizing procedure separation, where air traffic control grants one approach or departure clearance at a time. SATS HVO scenarios represented approaches and departure procedures as described in the SATS HVO concept of operations. Results from the experiment indicate that low time pilots were able to fly SATS HVO procedures and maintain self-separation as safely and proficiently as flying today's procedures.

Solving Two-Level Optimization Problems with Applications to Robust Design and Energy Markets

DTIC Science & Technology

2011-01-01

additional a transportation system operator (TSO) who manages the congestion and 172 flows. The TSO’s linear program is as follows (where other...were tested are shown in Table 5.11 below. Node 1 Node 2 Producer A Producer B Producer C Producer D Transmission System Operator 174... Systems to Solve Problems that are Not Linear. Operational Research Quarterly , 26, 609–618. 9. Beale, E., & Tomlin, J. (1970). Special Facilities

Reducing air pollutant emissions at airports by controlling aircraft ground operations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gelinas, C.G.; Fan, H.S.L.

1979-02-01

Average-day carbon monoxide, total hydrocarbon, and NO/sub x/ aircraft emissions and fuel use estimates (apportioned to takeoff, taxi, idle, and landing) for departure and arrival at Los Angeles and San Francisco International Airports were compared with emissions level and fuel use estimates for four emission reduction strategies (tow aircraft between runways and gates, shutdown one engine during taxiing, control departure time, and assign runways to minimize taxiing distance). The best strategy, the shutdown of one engine while taxiing, produces substantial emission reductions, cost benefits owing to fuel savings, and no apparent safety problems; aircraft towing reduced emissions significantly, but introducedmore » a number of safety problems.« less

Comparing Perceptions and Measures of Congestion

DOT National Transportation Integrated Search

2012-10-01

Peoples perception of congestion and the actual measured congestion do not always agree. Measured : congestion relates to the delay resulting from field measurements of traffic volume, speed, and travel : time. Peoples perception of congestion ...

Fuel Consumption and Emissions from Airport Taxi Operations

NASA Technical Reports Server (NTRS)

Jung, Yoon

2010-01-01

Developed a method to calculate fuel consumption and emissions of phases of taxi operations. Results at DFW showed that up to 18% of fuel can be saved by eliminating stop-and-go situations. Developed an energy efficient and environmentally friendly surface concept: Spot and Runway Departure Advisory (SARDA) tool. The SARDA tool has been identified as a potential candidate for a technology transfer to the FAA.

Surface Traffic Management Research

NASA Technical Reports Server (NTRS)

Jung, Yoo Chul

2012-01-01

This presentation discusses an overview of the surface traffic management research conducted by NASA Ames. The concept and human-in-the-loop simulation of the Spot and Runway Departure Advisor (SARDA), an integrated decision support tool for the tower controllers and airline ramp operators, is also discussed.

76 FR 28239 - Agency Information Collection Activities: Arrival and Departure Record (Forms I-94 and I-94W) and...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-16

.../startup costs and operations and maintenance costs). The comments that are submitted will be summarized... Number of Respondents: 100,000. Estimated Number of Total Annual Responses: 100,000. Estimated Time per...

TH-36 full closure construction evaluation of traffic operations alternatives.

DOT National Transportation Integrated Search

2010-01-01

According to the 2007 Urban Mobility Report, $78 billion was lost due to congestion on urban roadways. Many : urban corridors around the country experience demand that is close to or greater than the available capacity. : Although most agree that the...

Metropolitan transportation management center : a case study : Milwaukee MONITOR : addressing congestion while improving safety and air quality

DOT National Transportation Integrated Search

1999-10-01

The following case study provides a snapshot of Milwaukee's MONITOR transportation management center. It follows the outline provided in the companion document, Metropolitan Transportation Management Center Concepts of Operation - A Cross Cutting Stu...

Video Vehicle Detector Verification System (V2DVS) operators manual and project final report.

DOT National Transportation Integrated Search

2012-03-01

The accurate detection of the presence, speed and/or length of vehicles on roadways is recognized as critical for : effective roadway congestion management and safety. Vehicle presence sensors are commonly used for traffic : volume measurement and co...

Cost Estimates For Selected California Smart Traveler Operational Tests, Volume 1, Technical Report

DOT National Transportation Integrated Search

1993-03-01

THIS REPORT ALSO COMPARES THE COSTS OF USING "SMART-TRAVELER" APPROACHES WITH THE COSTS OF EXPANDING CONVENTIONAL TRANSIT SERVICES TO REDUCE TRAFFIC CONGESTION, AIR POLLUTION AND MOBILITY PROBLEMS IN SUBURBAN AREAS, WHERE MOST PEOPLE IN U.S. METROPOL...

Powered wheel for aircraft

NASA Technical Reports Server (NTRS)

Long, M. J.; Irick, S. C.; Van Ausdal, R. K.

1977-01-01

Single integral unit includes motor, gearbox, and clutch. Device has two-speed capability, fits within aerodynamic contours of aircraft, operates with onboard power source, does not interfere with normal landing gear functions, reduces use of regular brakes in congested areas, and provides locomotion and supplementary braking capability.

User delay costs due to work zone operations Near Echo Junction.

DOT National Transportation Integrated Search

2010-11-01

With the increasing number of road rehabilitation projects across the United States, the need to reduce user costs due to congestion is more important than ever. The Utah Department of Transportation (UDOT) has proposed replacing two I-80 bridges ove...

Innovative techniques for maintenance, repair and reconstruction (MRR) of asphalt roadways : final report.

DOT National Transportation Integrated Search

2017-08-01

Highway networks in the United States have been suffering from poor operational and structural condition states for the past decades. The consequent congestion problems often result in major delays, safety issues, and large amounts of additional fuel...

Maximizing port and transportation system productivity by exploring alternative port operation strategies.

DOT National Transportation Integrated Search

2011-06-01

Seaports are a critical transportation component that supports the nations economy. Many U.S. : ports are now experiencing significant truck congestion at the gate, which decreases the productivity of : ports and truck fleets (e.g. truck wait time...

Delivering Faster Congestion Feedback with the Mark-Front Strategy

NASA Technical Reports Server (NTRS)

Liu, Chunlei; Jain, Raj

2001-01-01

Computer networks use congestion feedback from the routers and destinations to control the transmission load. Delivering timely congestion feedback is essential to the performance of networks. Reaction to the congestion can be more effective if faster feedback is provided. Current TCP/IP networks use timeout, duplicate Acknowledgement Packets (ACKs) and explicit congestion notification (ECN) to deliver the congestion feedback, each provides a faster feedback than the previous method. In this paper, we propose a markfront strategy that delivers an even faster congestion feedback. With analytical and simulation results, we show that mark-front strategy reduces buffer size requirement, improves link efficiency and provides better fairness among users. Keywords: Explicit Congestion Notification, mark-front, congestion control, buffer size requirement, fairness.

Investigating the effect of freeway congestion thresholds on decision-making inputs.

DOT National Transportation Integrated Search

2010-05-01

Congestion threshold is embedded in the congestion definition. Two basic approaches exist in : current practice for setting the congestion threshold. One common approach uses the free-flow or : unimpeded conditions as the congestion threshold. ...

The Wait Calculation: The Broader Consequences of the Minimum Time from Now to Interstellar Destinations and its Significance to the Space Economy

NASA Astrophysics Data System (ADS)

Kennedy, A.

This paper summarises the wait calculation [1] of interstellar voyagers which finds the minimum time to destination given exponential growth in the rate of travel available to a civilisation. The minimum time obliges stellar system colonisers to consider departure times a significant risk factor in their voyages since a departure then to a destination will beat a departure made at any other time before or after. Generalised conclusions will be drawn about the significant impact that departures to interstellar destinations before, at, or after the minimum time will have on the economic potential of missions and on the inevitability of competition between them. There will be no international law operating in interstellar space and an ability to escape predatory actions en route, or at the destination, can only be done by precise calculations of departure times. Social and economic forces affecting the factors in the growth equation are discussed with reference to the probability of accelerating growth reaching the technological Singularity and strengthening the growth incentive trap. Islamic banking practices are discussed as a credible alternative to compounding interest bearing paper for funding the space economy in the long term and for supporting stakeholder investment in such long term mission development. The paper considers the essential free productivity of the Earth's biosphere and the capital accumulations made possible by land productivity are essential components to a viable long term space economy and that research into re-creating the costless productivity of the biosphere at a destination will determine both the mission's ultimate success and provide means of returns for stakeholders during the long build up. Conclusions of these arguments suggest that the Icarus project should ignore a robotic interstellar mission concept and develop a manned colonising mission from now.

Efficient algorithm for locating and sizing series compensation devices in large power transmission grids: I. Model implementation

NASA Astrophysics Data System (ADS)

Frolov, Vladimir; Backhaus, Scott; Chertkov, Misha

2014-10-01

We explore optimization methods for planning the placement, sizing and operations of flexible alternating current transmission system (FACTS) devices installed to relieve transmission grid congestion. We limit our selection of FACTS devices to series compensation (SC) devices that can be represented by modification of the inductance of transmission lines. Our master optimization problem minimizes the l1 norm of the inductance modification subject to the usual line thermal-limit constraints. We develop heuristics that reduce this non-convex optimization to a succession of linear programs (LP) that are accelerated further using cutting plane methods. The algorithm solves an instance of the MatPower Polish Grid model (3299 lines and 2746 nodes) in 40 seconds per iteration on a standard laptop—a speed that allows the sizing and placement of a family of SC devices to correct a large set of anticipated congestions. We observe that our algorithm finds feasible solutions that are always sparse, i.e., SC devices are placed on only a few lines. In a companion manuscript, we demonstrate our approach on realistically sized networks that suffer congestion from a range of causes, including generator retirement. In this manuscript, we focus on the development of our approach, investigate its structure on a small test system subject to congestion from uniform load growth, and demonstrate computational efficiency on a realistically sized network.

Efficient algorithm for locating and sizing series compensation devices in large power transmission grids: I. Model implementation

DOE PAGES

Frolov, Vladimir; Backhaus, Scott; Chertkov, Misha

2014-10-24

We explore optimization methods for planning the placement, sizing and operations of Flexible Alternating Current Transmission System (FACTS) devices installed to relieve transmission grid congestion. We limit our selection of FACTS devices to Series Compensation (SC) devices that can be represented by modification of the inductance of transmission lines. Our master optimization problem minimizes the l 1 norm of the inductance modification subject to the usual line thermal-limit constraints. We develop heuristics that reduce this non-convex optimization to a succession of Linear Programs (LP) which are accelerated further using cutting plane methods. The algorithm solves an instance of the MatPowermore » Polish Grid model (3299 lines and 2746 nodes) in 40 seconds per iteration on a standard laptop—a speed up that allows the sizing and placement of a family of SC devices to correct a large set of anticipated congestions. We observe that our algorithm finds feasible solutions that are always sparse, i.e., SC devices are placed on only a few lines. In a companion manuscript, we demonstrate our approach on realistically-sized networks that suffer congestion from a range of causes including generator retirement. In this manuscript, we focus on the development of our approach, investigate its structure on a small test system subject to congestion from uniform load growth, and demonstrate computational efficiency on a realistically-sized network.« less

Use of the retrograde limb of the internal mammary vein to avoid venous congestion in DIEP flap breast reconstruction: Further evidences of a reliable and time-sparing procedure.

PubMed

La Padula, Simone; Hersant, Barbara; Noel, Warren; Niddam, Jeremy; Hermeziu, Oana; Bouhassira, Jonathan; Bosc, Romain; Meningaud, Jean Paul

2016-09-01

Venous congestion is a common cause of DIEP flap failure. When identified intraoperatively, an additional venous anastomosis can improve the venous outflow and prevent flap failure. The aim of this study was to assess if the retrograde limb of the internal mammary vein (IMV) could be considered a good recipient vessel to be used when persistent flap congestion is present, and a second venous anastomosis is required. A retrospective study was conducted in 74 patients who had undergone DIEP flap breast reconstruction. Patients were classified into two groups: SVA (single venous anastomosis) and DVA (dual venous anastomosis). In the SVA group (n = 38), the IMV antegrade limb was used for venous drainage. A single DIEV (Deep Inferior Epigastric Vein) was anastomosed to the superior arm of the IMV. In the DVA group (n = 36), both the antegrade (superior) and retrograde (inferior) stumps of the IMV were used, connecting the larger DIEV to the antegrade IMV and the other DIEV or the SIEV (Superficial Inferior Epigastric Vein) to the IMV retrograde limb. No venous congestion or flap loss was observed when two venous anastomoses were performed using both the IMV antegrade and retrograde limbs (P = 0.3271). In the DVA group, no major complication occurred (P = 0.0453). Operative explorations were significantly reduced in the DVA group (P = 0.0242). These findings suggest that when an additional venous outflow is required, the use of the IMV retrograde limb may help to avoid flap venous congestion. © 2016 Wiley Periodicals, Inc. Microsurgery 36:447-452, 2016. © 2016 Wiley Periodicals, Inc.

Reducing congestion : congestion pricing has promise for improving use of transportation infrastructure

DOT National Transportation Integrated Search

2003-05-06

Congestion pricing can potentially reduce congestion by providing incentives for drivers to shift trips to off-peak periods, use less congested routes, or use alternative modes, thereby spreading out demand for available transportation infrastructure...

Understanding the topological characteristics and flow complexity of urban traffic congestion

NASA Astrophysics Data System (ADS)

Wen, Tzai-Hung; Chin, Wei-Chien-Benny; Lai, Pei-Chun

2017-05-01

For a growing number of developing cities, the capacities of streets cannot meet the rapidly growing demand of cars, causing traffic congestion. Understanding the spatial-temporal process of traffic flow and detecting traffic congestion are important issues associated with developing sustainable urban policies to resolve congestion. Therefore, the objective of this study is to propose a flow-based ranking algorithm for investigating traffic demands in terms of the attractiveness of street segments and flow complexity of the street network based on turning probability. Our results show that, by analyzing the topological characteristics of streets and volume data for a small fraction of street segments in Taipei City, the most congested segments of the city were identified successfully. The identified congested segments are significantly close to the potential congestion zones, including the officially announced most congested streets, the segments with slow moving speeds at rush hours, and the areas near significant landmarks. The identified congested segments also captured congestion-prone areas concentrated in the business districts and industrial areas of the city. Identifying the topological characteristics and flow complexity of traffic congestion provides network topological insights for sustainable urban planning, and these characteristics can be used to further understand congestion propagation.

Network congestion control algorithm based on Actor-Critic reinforcement learning model

NASA Astrophysics Data System (ADS)

Xu, Tao; Gong, Lina; Zhang, Wei; Li, Xuhong; Wang, Xia; Pan, Wenwen

2018-04-01

Aiming at the network congestion control problem, a congestion control algorithm based on Actor-Critic reinforcement learning model is designed. Through the genetic algorithm in the congestion control strategy, the network congestion problems can be better found and prevented. According to Actor-Critic reinforcement learning, the simulation experiment of network congestion control algorithm is designed. The simulation experiments verify that the AQM controller can predict the dynamic characteristics of the network system. Moreover, the learning strategy is adopted to optimize the network performance, and the dropping probability of packets is adaptively adjusted so as to improve the network performance and avoid congestion. Based on the above finding, it is concluded that the network congestion control algorithm based on Actor-Critic reinforcement learning model can effectively avoid the occurrence of TCP network congestion.

Small Aircraft Transportation System, Higher Volume Operations Concept: Normal Operations

NASA Technical Reports Server (NTRS)

Abbott, Terence S.; Jones, Kenneth M.; Consiglio, Maria C.; Williams, Daniel M.; Adams, Catherine A.

2004-01-01

This document defines the Small Aircraft Transportation System (SATS), Higher Volume Operations (HVO) concept for normal conditions. In this concept, a block of airspace would be established around designated non-towered, non-radar airports during periods of poor weather. Within this new airspace, pilots would take responsibility for separation assurance between their aircraft and other similarly equipped aircraft. Using onboard equipment and procedures, they would then approach and land at the airport. Departures would be handled in a similar fashion. The details for this operational concept are provided in this document.

Forearm vasodilatation following release of venous congestion

PubMed Central

Caro, C. G.; Foley, T. H.; Sudlow, M. F.

1970-01-01

1. The volume rate of forearm blood flow was measured with a mercury-in-rubber strain gauge, or with a water-filled plethysmograph, from 1 sec after termination of a 2-3 min period of venous congestion. 2. When congesting pressure had been less than 18 mm Hg, average post-congestion flow (five subjects) was constant during approx. 10 sec and not significantly different from resting flow. 3. When congesting pressure had been 30 mm Hg, average post-congestion flow (eight subjects) was 26% higher than resting, during 3-4 sec after release of congestion, but rose to 273% of resting during 4-6 sec after release of congestion. 4. In other studies forearm vascular resistance had been found normal or increased during such venous congestion, and theoretical studies here indicated that passive mechanical factors could not account for the delayed occurrence of high post-congestion flow. 5. It appears, therefore, that the forearm vascular bed dilates actively shortly after release of substantial venous congestion. It would seem more likely that a myogenic mechanism, rather than a metabolic one, is responsible. PMID:5532541

Guide for geometric design and operational factors that impact truck use of toll roads.

DOT National Transportation Integrated Search

2010-09-01

Texas has approximately 300 miles of toll roads, predominantly in the three largest and : most congested urban areas of Austin, Dallas, and Houston. The Texas Turnpike Authority : (TTA) Division of the Texas Department of Transportation (TxDOT) and t...

Variable message fog hazard warning signs to control vehicle operating characteristics : interim report, Interstate 5, North Albany.

DOT National Transportation Integrated Search

1972-04-01

This project is aimed at determining the effectiveness of variable message signs in controlling traffic on an Interstate highway during periods of hazardous driving conditions such as fog, vehicle accidents, or congestion. : The effectiveness of the ...

Real time estimation of arterial travel time and operational measures through integration of real time fixed sensor data and simulation.

DOT National Transportation Integrated Search

2012-02-01

A wide variety of advanced technological tools have been implemented throughout Georgias : transportation network to increase its efficiency. These systems are credited with reducing or : maintaining freeway congestion levels in light of increasin...

14 CFR 93.29 - International Arrival Authorizations.

Code of Federal Regulations, 2011 CFR

2011-01-01

... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Congestion and Delay Reduction... marketing arrangement unless the flight was predominately marketed, by contract, under the control of another Carrier. If the flight was under the marketing control of another Carrier or the entire inventory...

Integrating inland ports into the intermodal goods movement system for ports of Los Angeles and Long Beach.

DOT National Transportation Integrated Search

2008-02-01

Planners concerned with deep-water port operations are interested in strategies that improve : regional truck flows associated with the container trade while also mitigating related problems of : highway congestion and air pollution. An inland port o...

Big Savings from Smart Motors

NASA Technical Reports Server (NTRS)

1984-01-01

Chesebrough-Pond's operates 32 plants across the nation and in those plants are more than 10,000 electric motors. In an effort to cut down on waste of electrical power used by these motors, Chesebrough organized a Corporate Advanced Technology Group to devise ways of improving productivity and cut manufacturing costs. Chesebrough used NASA's Marshall Space Flight Center's Power Factor Controller technology as a departure point for development of their own computerized motor controller that enables motors to operate at maximum efficiency regardless of the motor's applications or operating condition.

Surgical treatment of atrioventricular canal defect.

PubMed

Hardesty, R L; Zuberbuhler, J R; Bahnson, H T

1975-11-01

Fifty-nine patients with congenital anomalies of the atrioventricular canal underwent operation and all survivors were followed up. In 42 patients with partial atrioventricular canal defects, ten had preoperative congestive heart failure. Three, or 7.1%, died of endomyocardial fibroelastosis, high pulmonary vascular resistance, and severe mitral regurgitation. A fourth patient later died of Wolff-Parkinson-White syndrome and fibrilation. Reoperations in five patients were all successful. No patients had persistent atrioventricular blocks, and all patients are asymptomatic. Two of these subjects continue to receive digoxin therapy, and one of them is believed to have substantial mitral insufficiency. Of the 17 patients who had complete atrioventricular canal defects, 13 had a divided common anterior leaflet attached to the septum by chordae tendineae, and four had undivided and unattached anterior leaflets. Two had previously undergone pulmonary banding, and nine were treated for congestive heart failure. Six died after operation. There were no reoperations. No patient presently has required a pacemaker. Two subjects have persistent cardiomegaly.

Research on Urban Road Traffic Congestion Charging Based on Sustainable Development

NASA Astrophysics Data System (ADS)

Ye, Sun

Traffic congestion is a major problem which bothers our urban traffic sustainable development at present. Congestion charging is an effective measure to alleviate urban traffic congestion. The paper first probes into several key issues such as the goal, the pricing, the scope, the method and the redistribution of congestion charging from theoretical angle. Then it introduces congestion charging practice in Singapore and London and draws conclusion and suggestion that traffic congestion charging should take scientific plan, support of public, public transportation development as the premise.

Interaction between worsening renal function and persistent congestion in acute decompensated heart failure.

PubMed

Wattad, Malak; Darawsha, Wisam; Solomonica, Amir; Hijazi, Maher; Kaplan, Marielle; Makhoul, Badira F; Abassi, Zaid A; Azzam, Zaher S; Aronson, Doron

2015-04-01

Worsening renal function (WRF) and congestion are inextricably related pathophysiologically, suggesting that WRF occurring in conjunction with persistent congestion would be associated with worse clinical outcome. We studied the interdependence between WRF and persistent congestion in 762 patients with acute decompensated heart failure (HF). WRF was defined as ≥0.3 mg/dl increase in serum creatinine above baseline at any time during hospitalization and persistent congestion as ≥1 sign of congestion at discharge. The primary end point was all-cause mortality with mean follow-up of 15 ± 9 months. Readmission for HF was a secondary end point. Persistent congestion was more common in patients with WRF than in patients with stable renal function (51.0% vs 26.6%, p <0.0001). Both persistent congestion and persistent WRF were significantly associated with mortality (both p <0.0001). There was a strong interaction (p = 0.003) between persistent WRF and congestion, such that the increased risk for mortality occurred predominantly with both WRF and persistent congestion. The adjusted hazard ratio for mortality in patients with persistent congestion as compared with those without was 4.16 (95% confidence interval [CI] 2.20 to 7.86) in patients with WRF and 1.50 (95% CI 1.16 to 1.93) in patients without WRF. In conclusion, persisted congestion is frequently associated with WRF. We have identified a substantial interaction between persistent congestion and WRF such that congestion portends increased mortality particularly when associated with WRF. Copyright © 2015 Elsevier Inc. All rights reserved.

47 CFR 73.1545 - Carrier frequency departure tolerances.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 4 2010-10-01 2010-10-01 false Carrier frequency departure tolerances. 73.1545... departure tolerances. (a) AM stations. The departure of the carrier frequency for monophonic transmissions.... The departure of the carrier frequency of Class A TV stations may not exceed the values specified in...

Delay-based virtual congestion control in multi-tenant datacenters

NASA Astrophysics Data System (ADS)

Liu, Yuxin; Zhu, Danhong; Zhang, Dong

2018-03-01

With the evolution of cloud computing and virtualization, the congestion control of virtual datacenters has become the basic issue for multi-tenant datacenters transmission. Regarding to the friendly conflict of heterogeneous congestion control among multi-tenant, this paper proposes a delay-based virtual congestion control, which translates the multi-tenant heterogeneous congestion control into delay-based feedback uniformly by setting the hypervisor translation layer, modifying three-way handshake of explicit feedback and packet loss feedback and throttling receive window. The simulation results show that the delay-based virtual congestion control can effectively solve the unfairness of heterogeneous feedback congestion control algorithms.

Data Bank 28DS - T-100 Domestic Segment Data - U.S. Air Carriers Traffic and Capacity Data.

DOT National Transportation Integrated Search

2013-07-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - U.S. Air Carriers Traffic and Capacity Data.

DOT National Transportation Integrated Search

2011-10-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - U.S. Air Carriers Traffic and Capacity Data.

DOT National Transportation Integrated Search

2011-05-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - U.S. Air Carriers Traffic and Capacity Data.

DOT National Transportation Integrated Search

2012-11-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

78 FR 32278 - Vogtle Electric Generating Station, Units 3 and 4; Southern Nuclear Operating Company; Change to...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-29

... Paragraph A.4 of Section VIII, ``Processes for Changes and Departures,'' Appendix D to 10 CFR part 52 to... standardization caused by the exemption; and F. the exemption will not result in a significant decrease in the...

46 CFR 45.191 - Pre-departure requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., verification of mooring/docking space availability, and weather forecast checks were performed, and record the... voyage, the towing vessel master must conduct the following: (a) Weather forecast. Determine the marine weather forecast along the planned route, and contact the dock operator at the destination port to get an...

46 CFR 45.191 - Pre-departure requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., verification of mooring/docking space availability, and weather forecast checks were performed, and record the... voyage, the towing vessel master must conduct the following: (a) Weather forecast. Determine the marine weather forecast along the planned route, and contact the dock operator at the destination port to get an...

46 CFR 45.191 - Pre-departure requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., verification of mooring/docking space availability, and weather forecast checks were performed, and record the... voyage, the towing vessel master must conduct the following: (a) Weather forecast. Determine the marine weather forecast along the planned route, and contact the dock operator at the destination port to get an...

46 CFR 45.191 - Pre-departure requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., verification of mooring/docking space availability, and weather forecast checks were performed, and record the... voyage, the towing vessel master must conduct the following: (a) Weather forecast. Determine the marine weather forecast along the planned route, and contact the dock operator at the destination port to get an...

New framework and decision support tool to warrant detour operations during freeway corridor incident management.

DOT National Transportation Integrated Search

2013-05-01

Up to 60% of freeway delays are due to non-recurrent congestion caused by reduced capacity on a freeway section coupled with long incident : durations. In such conditions, if proper detour strategies could be implemented in time, traffic could circum...

Intelligent Transport Systems in the Management of Road Transportation

NASA Astrophysics Data System (ADS)

Kalupová, Blanka; Hlavoň, Ivan

2016-11-01

Extension of European Union causes increase of free transfer of people and goods. At the same time they raised the problems associated with the transport, e.g. congestion and related accidents on roads, air traffic delays and more. To increase the efficiency and safety of transport, the European Commission supports the introduction of intelligent transport systems and services in all transport sectors. Implementation of intelligent transport systems and services in the road transport reduces accident frequency, increases the capacity of existing infrastructure and reduces congestions. Use of toll systems provides resources needed for the construction and operation of a new road network, improves public transport, cycling transport and walking transport, and also their multimodal integration with individual car transport.

Predictive onboard flow control for packet switching satellites

NASA Technical Reports Server (NTRS)

Bobinsky, Eric A.

1992-01-01

We outline two alternate approaches to predicting the onset of congestion in a packet switching satellite, and argue that predictive, rather than reactive, flow control is necessary for the efficient operation of such a system. The first method discussed is based on standard, statistical techniques which are used to periodically calculate a probability of near-term congestion based on arrival rate statistics. If this probability exceeds a present threshold, the satellite would transmit a rate-reduction signal to all active ground stations. The second method discussed would utilize a neural network to periodically predict the occurrence of buffer overflow based on input data which would include, in addition to arrival rates, the distributions of packet lengths, source addresses, and destination addresses.

Airport Pricing Strategies

NASA Technical Reports Server (NTRS)

Pels, Eric; Verhoef, Erik T.

2003-01-01

Conventional economic wisdom suggests that congestion pricing would be an appropriate response to cope with the growing congestion levels currently experienced at many airports. Several characteristics of aviation markets, however, may make naive congestion prices equal to the value of marginal travel delays a non-optimal response. This paper has developed a model of airport pricing that captures a number of these features. The model in particular reflects that airlines typically have market power and are engaged in oligopolistic competition at different sub-markets; that part of external travel delays that aircraft impose are internal to an operator and hence should not be accounted for in congestion tolls. We presented an analytical treatment for a simple bi-nodal symmetric network, which through the use of 'hyper-networks' would be readily applicable to dynamic problems (in discrete time) such as peak - off-peak differences, and some numerical exercises for the same symmetric network, which was only designed to illustrate the possible comparative static impacts of tolling, in addition to marginal equilibrium conditions as could be derived for the general model specification. Some main conclusions are that second-best optimal tolls are typically lower than what would be suggested by congestion costs alone and may even be negative, and that the toll as derived by Brueckner (2002) may not lead to an increase in total welfare. While Brueckner (2002) has made clear that congestion tolls on airports may be smaller than expected when congestion costs among aircraft are internal for a firm, our analysis adds to this that a further downward adjustment may be in order due to market power. The presence of market power (which causes prices to exceed marginal costs) may cause the pure congestion toll to be suboptimal, because the resulting decrease in demand is too high (the pure congestion tall does not take into account the decrease in consumer surplus). The various downward adjustments in welfare maximizing tolls may well cause the optimal values of these to be negative. Insofar as subsidization is considered unacceptable for whichever reason, our results warn that the most efficient among the non-negative tolls may actually be a zero toll; the pure congestion toll may actually decrease welfare compared to the base case. The model in this paper contains a few simplifying assumptions that may be relaxed in future work. Load factors and aircraft capacity are fixed in this model for simplicity. In a more advanced version of this model, load factors and aircraft capacity can be endogenized. This makes the derivation of the optimality conditions far more complicated, but it should be feasible in a numerical experiment. One can also add a fourth layer to the model, describing the airport's optimization problem. For example, the airport can maximize profits under a cost recovery constraint. The model then deals with interactions between four types of agents. No distinction is made between peak and off-peak traffic in this paper. Finally, the results of the numerical exercise in this paper need to be checked against an asymmetric equilibrium.

Scalable Heuristics for Planning, Placement and Sizing of Flexible AC Transmission System Devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frolov, Vladmir; Backhaus, Scott N.; Chertkov, Michael

Aiming to relieve transmission grid congestion and improve or extend feasibility domain of the operations, we build optimization heuristics, generalizing standard AC Optimal Power Flow (OPF), for placement and sizing of Flexible Alternating Current Transmission System (FACTS) devices of the Series Compensation (SC) and Static VAR Compensation (SVC) type. One use of these devices is in resolving the case when the AC OPF solution does not exist because of congestion. Another application is developing a long-term investment strategy for placement and sizing of the SC and SVC devices to reduce operational cost and improve power system operation. SC and SVCmore » devices are represented by modification of the transmission line inductances and reactive power nodal corrections respectively. We find one placement and sizing of FACTs devices for multiple scenarios and optimal settings for each scenario simultaneously. Our solution of the nonlinear and nonconvex generalized AC-OPF consists of building a convergent sequence of convex optimizations containing only linear constraints and shows good computational scaling to larger systems. The approach is illustrated on single- and multi-scenario examples of the Matpower case-30 model.« less

Electricity market pricing, risk hedging and modeling

NASA Astrophysics Data System (ADS)

Cheng, Xu

In this dissertation, we investigate the pricing, price risk hedging/arbitrage, and simplified system modeling for a centralized LMP-based electricity market. In an LMP-based market model, the full AC power flow model and the DC power flow model are most widely used to represent the transmission system. We investigate the differences of dispatching results, congestion pattern, and LMPs for the two power flow models. An appropriate LMP decomposition scheme to quantify the marginal costs of the congestion and real power losses is critical for the implementation of financial risk hedging markets. However, the traditional LMP decomposition heavily depends on the slack bus selection. In this dissertation we propose a slack-independent scheme to break LMP down into energy, congestion, and marginal loss components by analyzing the actual marginal cost of each bus at the optimal solution point. The physical and economic meanings of the marginal effect at each bus provide accurate price information for both congestion and losses, and thus the slack-dependency of the traditional scheme is eliminated. With electricity priced at the margin instead of the average value, the market operator typically collects more revenue from power sellers than that paid to power buyers. According to the LMP decomposition results, the revenue surplus is then divided into two parts: congestion charge surplus and marginal loss revenue surplus. We apply the LMP decomposition results to the financial tools, such as financial transmission right (FTR) and loss hedging right (LHR), which have been introduced to hedge against price risks associated to congestion and losses, to construct a full price risk hedging portfolio. The two-settlement market structure and the introduction of financial tools inevitably create market manipulation opportunities. We investigate several possible market manipulation behaviors by virtual bidding and propose a market monitor approach to identify and quantify such behavior. Finally, the complexity of the power market and size of the transmission grid make it difficult for market participants to efficiently analyze the long-term market behavior. We propose a simplified power system commercial model by simulating the PTDFs of critical transmission bottlenecks of the original system.

14 CFR 99.11 - ADIZ flight plan requirements.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false ADIZ flight plan requirements. 99.11... flight plan requirements. (a) No person may operate an aircraft into, within, or from a departure point within an ADIZ, unless the person files, activates, and closes a flight plan with the appropriate...

14 CFR 99.11 - ADIZ flight plan requirements.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false ADIZ flight plan requirements. 99.11... flight plan requirements. (a) No person may operate an aircraft into, within, or from a departure point within an ADIZ, unless the person files, activates, and closes a flight plan with the appropriate...

A 2040 Vision for the I-95 Coalition Region : Supporting Economic Growth in a Carbon-Constrained Environment

DOT National Transportation Integrated Search

2008-12-01

The I-95 Corridor Coalitions Vision project is a departure from the Coalitions historic role that focused primarily on shorter-term operational improvements in the corridor. In the past, most of the day-to-day issues confronting the Coalition m...

Deep Space Gateway Support of Lunar Surface Ops and Tele-Operational Transfer of Surface Assets to the Next Landing Site

NASA Astrophysics Data System (ADS)

Kring, D. A.

2018-02-01

The Deep Space Gateway can support astronauts on the lunar surface, providing them a departure and returning rendezvous point, a communication relay from the lunar farside to Earth, and a transfer point to Orion for return to Earth.

Thermal generation of the magnetic field in the surface layers of massive stars

NASA Astrophysics Data System (ADS)

Urpin, V.

2017-11-01

A new magnetic field-generation mechanism based on the Nernst effect is considered in hot massive stars. This mechanism can operate in the upper atmospheres of O and B stars where departures from the LTE form a region with the inverse temperature gradient.

46 CFR 196.15-7 - Verification of vessel compliance with applicable stability requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... stability requirements. 196.15-7 Section 196.15-7 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS OPERATIONS Test, Drills, and Inspections § 196.15-7 Verification of vessel compliance with applicable stability requirements. (a) After loading and prior to departure...

46 CFR 131.513 - Verification of compliance with applicable stability requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Verification of compliance with applicable stability...) OFFSHORE SUPPLY VESSELS OPERATIONS Tests, Drills, and Inspections § 131.513 Verification of compliance with applicable stability requirements. (a) After loading but before departure, and at other times necessary to...

46 CFR 131.513 - Verification of compliance with applicable stability requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Verification of compliance with applicable stability...) OFFSHORE SUPPLY VESSELS OPERATIONS Tests, Drills, and Inspections § 131.513 Verification of compliance with applicable stability requirements. (a) After loading but before departure, and at other times necessary to...

46 CFR 131.513 - Verification of compliance with applicable stability requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Verification of compliance with applicable stability...) OFFSHORE SUPPLY VESSELS OPERATIONS Tests, Drills, and Inspections § 131.513 Verification of compliance with applicable stability requirements. (a) After loading but before departure, and at other times necessary to...

46 CFR 196.15-7 - Verification of vessel compliance with applicable stability requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... stability requirements. 196.15-7 Section 196.15-7 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS OPERATIONS Test, Drills, and Inspections § 196.15-7 Verification of vessel compliance with applicable stability requirements. (a) After loading and prior to departure...

46 CFR 196.15-7 - Verification of vessel compliance with applicable stability requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... stability requirements. 196.15-7 Section 196.15-7 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS OPERATIONS Test, Drills, and Inspections § 196.15-7 Verification of vessel compliance with applicable stability requirements. (a) After loading and prior to departure...

00001:Data Bank 28DS - T-100 Domestic Segment Data - U.S. Air Carriers Traffic and Capacity Data.

DOT National Transportation Integrated Search

2005-12-01

00001:This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures p...

00001:Data Bank 28DS - T-100 Domestic Segment Data - U.S. Air Carriers Traffic and Capacity Data.

DOT National Transportation Integrated Search

2010-04-01

00001:This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures p...

00001:Data Bank 28DS - T-100 Domestic Segment Data - U.S. Air Carriers Traffic and Capacity Data.

DOT National Transportation Integrated Search

2009-02-01

00001:This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures p...

00001:Data Bank 28DS - T-100 Domestic Segment Data - U.S. Air Carriers Traffic and Capacity Data.

DOT National Transportation Integrated Search

2006-12-01

00001:This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures p...

00001:Data Bank 28DS - T-100 Domestic Segment Data - U.S. Air Carriers Traffic and Capacity Data.

DOT National Transportation Integrated Search

2010-01-01

00001:This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures p...

00001:Data Bank 28DS - T-100 Domestic Segment Data - U.S. Air Carriers Traffic and Capacity Data.

DOT National Transportation Integrated Search

2009-12-01

00001:This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures p...

00001:Data Bank 28DS - T-100 Domestic Segment Data - U.S. Air Carriers Traffic and Capacity Data.

DOT National Transportation Integrated Search

2008-12-01

00001:This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures p...

00001:Data Bank 28DS - T-100 Domestic Segment Data - U.S. Air Carriers Traffic and Capacity Data.

DOT National Transportation Integrated Search

2007-12-01

00001:This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures p...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2011-01

DOT National Transportation Integrated Search

2011-01-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2010-06

DOT National Transportation Integrated Search

2010-06-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2010-12

DOT National Transportation Integrated Search

2010-12-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2010-09

DOT National Transportation Integrated Search

2010-09-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2011-02

DOT National Transportation Integrated Search

2011-02-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2014-02

DOT National Transportation Integrated Search

2014-02-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2009-11

DOT National Transportation Integrated Search

2009-11-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2011-06

DOT National Transportation Integrated Search

2011-06-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2009-08

DOT National Transportation Integrated Search

2009-08-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2012-07

DOT National Transportation Integrated Search

2012-07-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2009-09

DOT National Transportation Integrated Search

2009-09-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2012-12

DOT National Transportation Integrated Search

2012-12-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2012-03

DOT National Transportation Integrated Search

2012-03-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2014-06

DOT National Transportation Integrated Search

2014-06-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2012-05

DOT National Transportation Integrated Search

2012-05-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2012-06

DOT National Transportation Integrated Search

2012-06-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2011-03

DOT National Transportation Integrated Search

2011-03-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2014-03

DOT National Transportation Integrated Search

2014-03-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2013-03

DOT National Transportation Integrated Search

2013-03-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2014-04

DOT National Transportation Integrated Search

2014-04-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2012-04

DOT National Transportation Integrated Search

2012-04-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2012-08

DOT National Transportation Integrated Search

2012-08-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2012-10

DOT National Transportation Integrated Search

2012-10-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2013-02

DOT National Transportation Integrated Search

2013-02-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2014-05

DOT National Transportation Integrated Search

2014-05-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2012-09

DOT National Transportation Integrated Search

2012-09-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2011-04

DOT National Transportation Integrated Search

2011-04-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2011-11

DOT National Transportation Integrated Search

2011-11-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2009-10

DOT National Transportation Integrated Search

2009-10-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2009-03

DOT National Transportation Integrated Search

2009-03-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2011-12

DOT National Transportation Integrated Search

2011-12-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2013-06

DOT National Transportation Integrated Search

2013-06-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2012-01

DOT National Transportation Integrated Search

2012-01-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2013-09

DOT National Transportation Integrated Search

2013-09-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2014-01

DOT National Transportation Integrated Search

2014-01-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2011-09

DOT National Transportation Integrated Search

2011-09-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2009-07

DOT National Transportation Integrated Search

2009-07-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2013-10

DOT National Transportation Integrated Search

2013-10-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2011-07

DOT National Transportation Integrated Search

2011-07-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2009-04

DOT National Transportation Integrated Search

2009-04-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2012-02

DOT National Transportation Integrated Search

2012-02-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2013-11

DOT National Transportation Integrated Search

2013-11-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2009-01

DOT National Transportation Integrated Search

2009-01-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2013-05

DOT National Transportation Integrated Search

2013-05-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2009-06

DOT National Transportation Integrated Search

2009-06-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2011-08

DOT National Transportation Integrated Search

2011-08-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2009-05

DOT National Transportation Integrated Search

2009-05-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

48 CFR 252.236-7005 - Airfield safety precautions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... the maximum width of 16,000 feet at the end. (ii) The approach-departure clearance zone is the ground... ground area under the transitional surface. (It adjoins the primary surface, clear zone, and approach... while— (i) Operating all ground equipment (mobile or stationary); (ii) Placing all materials; and (iii...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2010-11

DOT National Transportation Integrated Search

2010-11-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

46 CFR 45.191 - Pre-departure requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... voyage, the towing vessel master must conduct the following: (a) Weather forecast. Determine the marine weather forecast along the planned route, and contact the dock operator at the destination port to get an update on local weather conditions. (b) Inspection. Inspect each barge of the tow to ensure that they...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2010-02

DOT National Transportation Integrated Search

2010-02-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2010-07

DOT National Transportation Integrated Search

2010-07-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2010-08

DOT National Transportation Integrated Search

2010-08-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2010-01

DOT National Transportation Integrated Search

2010-01-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Data Bank 28DS - T-100 Domestic Segment Data - US Air Carriers Traffic and Capacity Data : [2010-05

DOT National Transportation Integrated Search

2010-05-01

This CD presents data reported by U.S. carriers operating nonstop between airports located within the boundaries of the United States and its territories. These data fields contain information by aircraft type and service class for departures perform...

Optimal Integration of Departure and Arrivals in Terminal Airspace

NASA Technical Reports Server (NTRS)

Xue, Min; Zelinski, Shannon Jean

2012-01-01

Coordination of operations with spatially and temporally shared resources such as route segments, fixes, and runways improves the efficiency of terminal airspace management. Problems in this category include scheduling and routing, thus they are normally difficult to solve compared with pure scheduling problems. In order to reduce the computational time, a fast time algorithm formulation using a non-dominated sorting genetic algorithm (NSGA) was introduced in this work and applied to a test case based on existing literature. The experiment showed that new method can solve the whole problem in fast time instead of solving sub-problems sequentially with a window technique. The results showed a 60% or 406 second delay reduction was achieved by sharing departure fixes (more details on the comparison with MILP results will be presented in the final paper). Furthermore, the NSGA algorithm was applied to a problem in LAX terminal airspace, where interactions between 28% of LAX arrivals and 10% of LAX departures are resolved by spatial segregation, which may introduce unnecessary delays. In this work, spatial segregation, temporal segregation, and hybrid segregation were formulated using the new algorithm. Results showed that spatial and temporal segregation approaches achieved similar delay. Hybrid segregation introduced much less delay than the other two approaches. For a total of 9 interacting departures and arrivals, delay reduction varied from 4 minutes to 6.4 minutes corresponding flight time uncertainty from 0 to 60 seconds. Considering the amount of flights that could be affected, total annual savings with hybrid segregation would be significant.

Relationship Between Carbon Dioxide Levels and Reported Congestion and Headaches on the International Space Station

NASA Technical Reports Server (NTRS)

Cole, Robert; Wear, Mary; Young, Millennia; Cobel, Christopher; Mason, Sara

2017-01-01

Congestion is commonly reported during spaceflight, and most crewmembers have reported using medications for congestion during International Space Station (ISS) missions. Although congestion has been attributed to fluid shifts during spaceflight, fluid status reaches equilibrium during the first week after launch while congestion continues to be reported throughout long duration missions. Congestion complaints have anecdotally been reported in relation to ISS CO2 levels; this evaluation was undertaken to determine whether or not an association exists. METHODS: Reported headaches, congestion symptoms, and CO2 levels were obtained for ISS expeditions 2-31, and time-weighted means and single-point maxima were determined for 24-hour (24hr) and 7-day (7d) periods prior to each weekly private medical conference. Multiple imputation addressed missing data, and logistic regression modeled the relationship between probability of reported event of congestion or headache and CO2 levels, adjusted for possible confounding covariates. The first seven days of spaceflight were not included to control for fluid shifts. Data were evaluated to determine the concentration of CO2 required to maintain the risk of congestion below 1% to allow for direct comparison with a previously published evaluation of CO2 concentrations and headache. RESULTS: This study confirmed a previously identified significant association between CO2 and headache and also found a significant association between CO2 and congestion. For each 1-mm Hg increase in CO2, the odds of a crew member reporting congestion doubled. The average 7-day CO2 would need to be maintained below 1.5 mmHg to keep the risk of congestion below 1%. The predicted probability curves of ISS headache and congestion curves appear parallel when plotted against ppCO2 levels with congestion occurring at approximately 1mmHg lower than a headache would be reported. DISCUSSION: While the cause of congestion is multifactorial, this study showed congestion is associated with CO2 levels on ISS. Data from additional expeditions could be incorporated to further assess this finding. CO2 levels are also associated with reports of headaches on ISS. While it may be expected for astronauts with congestion to also complain of headaches, these two symptoms are commonly mutually exclusive. Furthermore, it is unknown if a temporal CO2 relationship exists between congestion and headache on ISS. CO2 levels were time-weighted for 24hr and 7d, and thus the time course of congestion leading to headache was not assessed; however, congestion could be an early CO2-related symptom when compared to headache. Future studies evaluating the association of CO2-related congestion leading to headache would be difficult due to the relatively stable daily CO2 levels on ISS currently, but a systematic study could be implemented on-orbit if desired.

Violent Mexican Transnational Criminal Organizations in Texas: Political Discourse and an Argument for Reality

DTIC Science & Technology

2012-09-01

control as did their Colombian predecessors, the Cali and Medellin cartels.11 In fact, they operate in quite the opposite manner and are in constant...Ibid. 3 Recent U.S. legislation requested these groups be designated foreign terrorist organizations.13 This is a notable departure and for the first...opinion in general.”16 Legislation offered before Congress by Congressman Michael McCaul asserts they “operate in the

Full road closure for work zone operations, a cross-cutting study : reducing congestion and crashes through full road closure for maintenance and construction.

DOT National Transportation Integrated Search

2003-08-01

The objective of this report is to raise awareness among designers construction engineers, and managers of the applications and benefits of full road closure during rehabilitation and construction activities. Based on interviews with project personne...

Strategic approaches at the corridor and network level to minimize disruption from the renewal process. [supporting datasets

DOT National Transportation Integrated Search

2017-01-01

As our highway infrastructure continues to age, there is the imperative need to renew the entire network while keeping it operational. Moreover, many highway corridors and regional networks are becoming ever more congested. As a result there is an in...

Heavy vehicle performance during recovery from forced-flow urban freeway conditions due to incidents, work zones and recurring congestion.

DOT National Transportation Integrated Search

2013-12-01

Information contained in the Highway Capacity Manual on the influence heavy vehicles have on freeway traffic : operations has been based on few field data collection efforts and relied mostly on traffic simulation efforts. In the : 2010 Manual heavy ...

77 FR 21890 - Drawbridge Operation Regulation; Sturgeon Bay Ship Canal, Sturgeon Bay, WI

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-12

... Street and Maple-Oregon Bridges so vehicular traffic congestion would not develop on downtown Sturgeon... the efficient movement of vehicular traffic in Sturgeon Bay. The Sturgeon Bay Ship Canal is... experiences a significant increase in vehicular and vessel traffic during the peak tourist and navigation...

Integrated corridor management : analysis, modeling, and simulation for the U.S.-75 corridor in Dallas, Texas – post-deployment assessment report.

DOT National Transportation Integrated Search

2016-11-01

The U.S. Department of Transportation Integrated Corridor Management (ICM) Initiative aims to advance the state of the practice in transportation corridor operations to manage congestion. Through the deployment of ICM at the two selected Demonstratio...

U28 : longer combination vehicle's impact on improving operational efficiency, freight flows and traffic congestion.

DOT National Transportation Integrated Search

2011-12-01

Longer Combination Vehicles (LCVs) are able to carry more freight than conventional single trailer trucks. As a result, these trucks can increase efficiencies and benefits for freight movements as less fuel and less labor is used per ton of cargo. Ho...

Summary of International Border Crossings Roundtable Meeting Held in St. Louis, Missouri, June 9, 1993

DOT National Transportation Integrated Search

1999-06-01

This paper documents studies of three congested weigh stations. At each station current operating policy and traffic levels result in frequent occasions where the queue of trucks threatens to back up onto the highway, and the scales must be closed to...

Integrated corridor management analysis, modeling, and simulation for the I-15 corridor in San Diego, California post-deployment assessment report.

DOT National Transportation Integrated Search

2016-12-01

The U.S. Department of Transportation Integrated Corridor Management (ICM) Initiative aims to advance the state of the practice in transportation corridor operations to manage congestion. Through the deployment of ICM at the two selected Demonstratio...

Coordinated Traffic Incident and Congestion Management (TIM-CM) : Mitigating Regional Impacts of Major Traffic Incidents in the Seattle I-5 Corridor

DOT National Transportation Integrated Search

2018-02-02

Within the Seattle metropolitan area, traffic incident management (TIM) operations provide a multi-jurisdictional and coordinated strategy to detect, respond to, and clear traffic incidents so that traffic flow can be restored quickly and safely. The...

A Study of the Effects of Congestion Information and a Priority Boarding Pass in a Theme Park with Multi-Agents

NASA Astrophysics Data System (ADS)

Tone, Tetsuya; Kohara, Kazuhiro

We have investigated ways to reduce congestion in a theme park with multi-agents. We constructed a theme park model called Digital Park 1.0 with twenty-three attractions similar in form to Tokyo Disney Sea. We consider not only congestion information (number of vistors standing in line at each attraction) but also the advantage of a priority boarding pass, like Fast Pass which is used at Tokyo Disney Sea. The congestion-information-usage ratio, which reflects the ratio of visitors who behave according to congestion information, was changed from 0% to 100% in both models, with and without priority boarding pass. The “mean stay time of visitors" is a measure of satisfaction. The smaller mean stay time, the larger degree of satisfaction. Here, a short stay time means a short wait time. The resluts of each simulation are averaged over ten trials. The main results are as follows. (1) When congestion-information-usage ratio increased, the mean stay time decreases. When 20% of visitors behaved according to congestion information, the mean stay time was reduced by 30%. (2) A priority boarding pass reduced congestion, and mean stay time was reduced by 15%. (3) When visitors used congestion information and a priority boarding pass, mean stay time was further reduced. When the congestion-information-usage ratio was 20%, mean stay time was reduced by 35%. (4) When congestion-information-usage ratio was over 50%, the congestion reduction effects reached saturation.

22 CFR 46.2 - Authority of departure-control officer to prevent alien's departure from the United States.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Authority of departure-control officer to prevent alien's departure from the United States. 46.2 Section 46.2 Foreign Relations DEPARTMENT OF STATE VISAS CONTROL OF ALIENS DEPARTING FROM THE UNITED STATES § 46.2 Authority of departure-control officer...

22 CFR 46.2 - Authority of departure-control officer to prevent alien's departure from the United States.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Authority of departure-control officer to prevent alien's departure from the United States. 46.2 Section 46.2 Foreign Relations DEPARTMENT OF STATE VISAS CONTROL OF ALIENS DEPARTING FROM THE UNITED STATES § 46.2 Authority of departure-control officer...

22 CFR 46.2 - Authority of departure-control officer to prevent alien's departure from the United States.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Authority of departure-control officer to prevent alien's departure from the United States. 46.2 Section 46.2 Foreign Relations DEPARTMENT OF STATE VISAS CONTROL OF ALIENS DEPARTING FROM THE UNITED STATES § 46.2 Authority of departure-control officer...

22 CFR 46.2 - Authority of departure-control officer to prevent alien's departure from the United States.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Authority of departure-control officer to prevent alien's departure from the United States. 46.2 Section 46.2 Foreign Relations DEPARTMENT OF STATE VISAS CONTROL OF ALIENS DEPARTING FROM THE UNITED STATES § 46.2 Authority of departure-control officer...

Dynamic, stochastic models for congestion pricing and congestion securities.

DOT National Transportation Integrated Search

2010-12-01

This research considers congestion pricing under demand uncertainty. In particular, a robust optimization (RO) approach is applied to optimal congestion pricing problems under user equilibrium. A mathematical model is developed and an analysis perfor...

An Integrated Gate Turnaround Management Concept Leveraging Big Data Analytics for NAS Performance Improvements

NASA Technical Reports Server (NTRS)

Chung, William W.; Ingram, Carla D.; Ahlquist, Douglas Kurt; Chachad, Girish H.

2016-01-01

"Gate Turnaround" plays a key role in the National Air Space (NAS) gate-to-gate performance by receiving aircraft when they reach their destination airport, and delivering aircraft into the NAS upon departing from the gate and subsequent takeoff. The time spent at the gate in meeting the planned departure time is influenced by many factors and often with considerable uncertainties. Uncertainties such as weather, early or late arrivals, disembarking and boarding passengers, unloading/reloading cargo, aircraft logistics/maintenance services and ground handling, traffic in ramp and movement areas for taxi-in and taxi-out, and departure queue management for takeoff are likely encountered on the daily basis. The Integrated Gate Turnaround Management (IGTM) concept is leveraging relevant historical data to support optimization of the gate operations, which include arrival, at the gate, departure based on constraints (e.g., available gates at the arrival, ground crew and equipment for the gate turnaround, and over capacity demand upon departure), and collaborative decision-making. The IGTM concept provides effective information services and decision tools to the stakeholders, such as airline dispatchers, gate agents, airport operators, ramp controllers, and air traffic control (ATC) traffic managers and ground controllers to mitigate uncertainties arising from both nominal and off-nominal airport gate operations. IGTM will provide NAS stakeholders customized decision making tools through a User Interface (UI) by leveraging historical data (Big Data), net-enabled Air Traffic Management (ATM) live data, and analytics according to dependencies among NAS parameters for the stakeholders to manage and optimize the NAS performance in the gate turnaround domain. The application will give stakeholders predictable results based on the past and current NAS performance according to selected decision trees through the UI. The predictable results are generated based on analysis of the unique airport attributes (e.g., runway, taxiway, terminal, and gate configurations and tenants), and combined statistics from past data and live data based on a specific set of ATM concept-of-operations (ConOps) and operational parameters via systems analysis using an analytic network learning model. The IGTM tool will then bound the uncertainties that arise from nominal and off-nominal operational conditions with direct assessment of the gate turnaround status and the impact of a certain operational decision on the NAS performance, and provide a set of recommended actions to optimize the NAS performance by allowing stakeholders to take mitigation actions to reduce uncertainty and time deviation of planned operational events. An IGTM prototype was developed at NASA Ames Simulation Laboratories (SimLabs) to demonstrate the benefits and applicability of the concept. A data network, using the System Wide Information Management (SWIM)-like messaging application using the ActiveMQ message service, was connected to the simulated data warehouse, scheduled flight plans, a fast-time airport simulator, and a graphic UI. A fast-time simulation was integrated with the data warehouse or Big Data/Analytics (BAI), scheduled flight plans from Aeronautical Operational Control AOC, IGTM Controller, and a UI via a SWIM-like data messaging network using the ActiveMQ message service, illustrated in Figure 1, to demonstrate selected use-cases showing the benefits of the IGTM concept on the NAS performance.

Mariner Mars 1971 science operational support equipment

NASA Technical Reports Server (NTRS)

1971-01-01

The Mariner Mars 1971 science operational support equipment (SOSE) was developed to support the checkout of the proof test model and flight spacecraft. The test objectives of the SOSE and how these objectives were implemented are discussed. Attention is focused on the computer portion of the SOSE, since incorporation of a computer in ground checkout equipment represents a major departure from the support equipment concepts previously used. A functional description of the major hardware elements contained in the SOSE is also included, along with the operational performance of the SOSE during spacecraft testing.

Validation of Aircraft Noise Prediction Models at Low Levels of Exposure

NASA Technical Reports Server (NTRS)

Page, Juliet A.; Hobbs, Christopher M.; Plotkin, Kenneth J.; Stusnick, Eric; Shepherd, Kevin P. (Technical Monitor)

2000-01-01

Aircraft noise measurements were made at Denver International Airport for a period of four weeks. Detailed operational information was provided by airline operators which enabled noise levels to be predicted using the FAA's Integrated Noise Model. Several thrust prediction techniques were evaluated. Measured sound exposure levels for departure operations were found to be 4 to 10 dB higher than predicted, depending on the thrust prediction technique employed. Differences between measured and predicted levels are shown to be related to atmospheric conditions present at the aircraft altitude.

Traffic congestion and reliability : linking solutions to problems.

DOT National Transportation Integrated Search

2004-07-19

The Traffic Congestion and Reliability: Linking Solutions to Problems Report provides : a snapshot of congestion in the United States by summarizing recent trends in : congestion, highlighting the role of unreliable travel times in the effects of con...

Lunar mission safety and rescue: Escape/rescue analysis and plan

NASA Technical Reports Server (NTRS)

1971-01-01

The results are presented of the technical analysis of escape/rescue/survival situations, crew survival techniques, alternate escape/rescue approaches and vehicles, and the advantages and disadvantages of each for advanced lunar exploration. Candidate escape/rescue guidelines are proposed and elements of a rescue plan developed. The areas of discussions include the following: lunar arrival/departure operations, lunar orbiter operations, lunar surface operations, lunar surface base escape/rescue analysis, lander tug location operations, portable airlock, emergency pressure suit, and the effects of no orbiting lunar station, no lunar surface base, and no foreign lunar orbit/surface operations on the escape/rescue plan.

Air Traffic Control Response to Delays: A System Study of Newark International Airport

NASA Technical Reports Server (NTRS)

Evans, Antony D.; Clarke, John-Paul

2002-01-01

Airport delays are a significant problem in the United States air transportation system. Between 1999 and 2000 the number of flights delayed increased by 20 percent despite only a 0.4% increase in total operations. Newark International Airport (EWR), one of New York City's primary airports, is one of the airports in the United States most impacted by delays. Newark had the highest percentage of operations delayed in 1999, and was second only to LaGuardia Airport in 2000. Nearly 85% of delays at Newark are caused by adverse weather impacting an airport that may be characterized as having limited capacity and a very full schedule. Although Newark is heavily impacted by weather, delays have not increased significantly since 1998. This indicates that the airlines, air traffic control (ATC), and the Port Authority of New York and New Jersey have successfully adapted. On June 29, 2000, a research team from MIT visited Newark airport to assess the effectiveness of any adaptations made, and to collect data on airline and ATC departure operations, and of the national and local weather affecting the airport. Airline and ATC personnel were also interviewed. Results of this study indicate that airspace capacity limitations downstream of the airport are a primary flow constraint at the airport, and that these constraints are the source of most surface delays. A number of tactical ATC responses to delays were examined, including the application of restrictions, re-routing with the help of the National Playbook, and the use of decision-aiding tools such as the Dynamic Spacing Program (DSP) and the Integrated Terminal Weather System (ITWS). Improved interfacility communications and further utilization of runway 11-29 were identified as other tactical responses to delays, whilst the formation of the Air Traffic Control System Command Center and the New York Airspace redesign were identified as thekey strategic ATC responses to delays. Particularly the New York airspace redesign has great potential to reduce delays at the airport. Because delays at Newark are caused by downstream flow constraints, the responses at the airport can be applied to other airports as delays from downstream constraints increase. Such an increase in delays system wide from downstream constraints is inevitable as the system becomes more congested.

Surface Management System Departure Event Data Analysis

NASA Technical Reports Server (NTRS)

Monroe, Gilena A.

2010-01-01

This paper presents a data analysis of the Surface Management System (SMS) performance of departure events, including push-back and runway departure events.The paper focuses on the detection performance, or the ability to detect departure events, as well as the prediction performance of SMS. The results detail a modest overall detection performance of push-back events and a significantly high overall detection performance of runway departure events. The overall detection performance of SMS for push-back events is approximately 55%.The overall detection performance of SMS for runway departure events nears 100%. This paper also presents the overall SMS prediction performance for runway departure events as well as the timeliness of the Aircraft Situation Display for Industry data source for SMS predictions.

A Bayesian ridge regression analysis of congestion's impact on urban expressway safety.

PubMed

Shi, Qi; Abdel-Aty, Mohamed; Lee, Jaeyoung

2016-03-01

With the rapid growth of traffic in urban areas, concerns about congestion and traffic safety have been heightened. This study leveraged both Automatic Vehicle Identification (AVI) system and Microwave Vehicle Detection System (MVDS) installed on an expressway in Central Florida to explore how congestion impacts the crash occurrence in urban areas. Multiple congestion measures from the two systems were developed. To ensure more precise estimates of the congestion's effects, the traffic data were aggregated into peak and non-peak hours. Multicollinearity among traffic parameters was examined. The results showed the presence of multicollinearity especially during peak hours. As a response, ridge regression was introduced to cope with this issue. Poisson models with uncorrelated random effects, correlated random effects, and both correlated random effects and random parameters were constructed within the Bayesian framework. It was proven that correlated random effects could significantly enhance model performance. The random parameters model has similar goodness-of-fit compared with the model with only correlated random effects. However, by accounting for the unobserved heterogeneity, more variables were found to be significantly related to crash frequency. The models indicated that congestion increased crash frequency during peak hours while during non-peak hours it was not a major crash contributing factor. Using the random parameter model, the three congestion measures were compared. It was found that all congestion indicators had similar effects while Congestion Index (CI) derived from MVDS data was a better congestion indicator for safety analysis. Also, analyses showed that the segments with higher congestion intensity could not only increase property damage only (PDO) crashes, but also more severe crashes. In addition, the issues regarding the necessity to incorporate specific congestion indicator for congestion's effects on safety and to take care of the multicollinearity between explanatory variables were also discussed. By including a specific congestion indicator, the model performance significantly improved. When comparing models with and without ridge regression, the magnitude of the coefficients was altered in the existence of multicollinearity. These conclusions suggest that the use of appropriate congestion measure and consideration of multicolilnearity among the variables would improve the models and our understanding about the effects of congestion on traffic safety. Copyright © 2015 Elsevier Ltd. All rights reserved.

Development of an Aircraft Approach and Departure Atmospheric Profile Generation Algorithm

NASA Technical Reports Server (NTRS)

Buck, Bill K.; Velotas, Steven G.; Rutishauser, David K. (Technical Monitor)

2004-01-01

In support of NASA Virtual Airspace Modeling and Simulation (VAMS) project, an effort was initiated to develop and test techniques for extracting meteorological data from landing and departing aircraft, and for building altitude based profiles for key meteorological parameters from these data. The generated atmospheric profiles will be used as inputs to NASA s Aircraft Vortex Spacing System (AVOLSS) Prediction Algorithm (APA) for benefits and trade analysis. A Wake Vortex Advisory System (WakeVAS) is being developed to apply weather and wake prediction and sensing technologies with procedures to reduce current wake separation criteria when safe and appropriate to increase airport operational efficiency. The purpose of this report is to document the initial theory and design of the Aircraft Approach Departure Atmospheric Profile Generation Algorithm.

Launch and Assembly Reliability Analysis for Human Space Exploration Missions

NASA Technical Reports Server (NTRS)

Cates, Grant; Gelito, Justin; Stromgren, Chel; Cirillo, William; Goodliff, Kandyce

2012-01-01

NASA's future human space exploration strategy includes single and multi-launch missions to various destinations including cis-lunar space, near Earth objects such as asteroids, and ultimately Mars. Each campaign is being defined by Design Reference Missions (DRMs). Many of these missions are complex, requiring multiple launches and assembly of vehicles in orbit. Certain missions also have constrained departure windows to the destination. These factors raise concerns regarding the reliability of launching and assembling all required elements in time to support planned departure. This paper describes an integrated methodology for analyzing launch and assembly reliability in any single DRM or set of DRMs starting with flight hardware manufacturing and ending with final departure to the destination. A discrete event simulation is built for each DRM that includes the pertinent risk factors including, but not limited to: manufacturing completion; ground transportation; ground processing; launch countdown; ascent; rendezvous and docking, assembly, and orbital operations leading up to trans-destination-injection. Each reliability factor can be selectively activated or deactivated so that the most critical risk factors can be identified. This enables NASA to prioritize mitigation actions so as to improve mission success.

Pre-departure preparation for international clinical work: a handbook.

PubMed

Edwardson, Jill; Owens, Lauren; Moran, Dane; Aluri, James; Kironji, Antony; Chen, Chi Chiung Grace

2015-08-01

International clinical experiences are increasingly popular among medical students, residents, fellows, and practitioners. Adequate pre-departure training is an integral part of a meaningful, productive, and safe international experience. At Johns Hopkins University School of Medicine, we have developed a pre-departure handbook to assist practitioners in preparing for global health work. The handbook draws from current global health education literature, existing handbooks, and expert experiences, and includes information about logistical and cultural preparations. While a pre-departure handbook cannot serve as a substitute for a comprehensive pre-departure training program, it can be a useful introduction to the pre-departure process.

A kinematic wave model in Lagrangian coordinates incorporating capacity drop: Application to homogeneous road stretches and discontinuities

NASA Astrophysics Data System (ADS)

Yuan, Kai; Knoop, Victor L.; Hoogendoorn, Serge P.

2017-01-01

On freeways, congestion always leads to capacity drop. This means the queue discharge rate is lower than the pre-queue capacity. Our recent research findings indicate that the queue discharge rate increases with the speed in congestion, that is the capacity drop is strongly correlated with the congestion state. Incorporating this varying capacity drop into a kinematic wave model is essential for assessing consequences of control strategies. However, to the best of authors' knowledge, no such a model exists. This paper fills the research gap by presenting a Lagrangian kinematic wave model. "Lagrangian" denotes that the new model is solved in Lagrangian coordinates. The new model can give capacity drops accompanying both of stop-and-go waves (on homogeneous freeway section) and standing queues (at nodes) in a network. The new model can be applied in a network operation. In this Lagrangian kinematic wave model, the queue discharge rate (or the capacity drop) is a function of vehicular speed in traffic jams. Four case studies on links as well as at lane-drop and on-ramp nodes show that the Lagrangian kinematic wave model can give capacity drops well, consistent with empirical observations.

Solving the negative impact of congestion in the postanesthesia care unit: a cost of opportunity analysis.

PubMed

Ruiz-Patiño, Alejandro; Acosta-Ospina, Laura Elena; Rueda, Juan-David

2017-04-01

Congestion in the postanesthesia care unit (PACU) leads to the formation of waiting queues for patients being transferred after surgery, negatively affecting hospital resources. As patients recover in the operating room, incoming surgeries are delayed. The purpose of this study was to establish the impact of this phenomenon in multiple settings. An operational mathematical study based on the queuing theory was performed. Average queue length, average queue waiting time, and daily queue waiting time were evaluated. Calculations were based on the mean patient daily flow, PACU length of stay, occupation, and current number of beds. Data was prospectively collected during a period of 2 months, and the entry and exit time was recorded for each patient taken to the PACU. Data was imputed in a computational model made with MS Excel. To account for data uncertainty, deterministic and probabilistic sensitivity analyses for all dependent variables were performed. With a mean patient daily flow of 40.3 and an average PACU length of stay of 4 hours, average total lost surgical opportunity time was estimated at 2.36 hours (95% CI: 0.36-4.74 hours). Cost of opportunity was calculated at $1592 per lost hour. Sensitivity analysis showed that an increase of two beds is required to solve the queue formation. When congestion has a negative impact on cost of opportunity in the surgical setting, queuing analysis grants definitive actions to solve the problem, improving quality of service and resource utilization. Copyright © 2016 Elsevier Inc. All rights reserved.

Desloratadine and pseudoephedrine combination therapy as a comprehensive treatment for allergic rhinitis and nasal congestion.

PubMed

Anolik, Robert

2009-06-01

Allergic rhinitis (AR) is rapidly increasing in global prevalence. Symptoms of AR, particularly nasal congestion, can cause quality of life (QoL) impairment. Second-generation antihistamines are a recommended first-line therapy for AR but are not viewed as very effective for the treatment of congestion. Therefore, an antihistamine plus a decongestant, such as the combination of desloratadine and pseudoephedrine, is a convenient and efficacious treatment. To review the clinical evidence on the efficacy and safety of combination desloratadine/pseudoephedrine for the treatment of AR symptoms, particularly nasal congestion. Four large studies found that improvement in nasal congestion is enhanced when patients are treated with combination desloratadine/pseudoephedrine. The combination drug significantly improved mean reflective nasal congestion scores in these studies compared with either component as monotherapy (p

Minimally invasive strabismus surgery versus paralimbal approach: A randomized, parallel design study is minimally invasive strabismus surgery worth the effort?

PubMed Central

Sharma, Richa; Amitava, Abadan K; Bani, Sadat AO

2014-01-01

Introduction: Minimal access surgery is common in all fields of medicine. We compared a new minimally invasive strabismus surgery (MISS) approach with a standard paralimbal strabismus surgery (SPSS) approach in terms of post-operative course. Materials and Methods: This parallel design study was done on 28 eyes of 14 patients, in which one eye was randomized to MISS and the other to SPSS. MISS was performed by giving two conjunctival incisions parallel to the horizontal rectus muscles; performing recession or resection below the conjunctival strip so obtained. We compared post-operative redness, congestion, chemosis, foreign body sensation (FBS), and drop intolerance (DI) on a graded scale of 0 to 3 on post-operative day 1, at 2-3 weeks, and 6 weeks. In addition, all scores were added to obtain a total inflammatory score (TIS). Statistical Analysis: Inflammatory scores were analyzed using Wilcoxon's signed rank test. Results: On the first post-operative day, only FBS (P =0.01) and TIS (P =0.04) showed significant difference favoring MISS. At 2-3 weeks, redness (P =0.04), congestion (P =0.04), FBS (P =0.02), and TIS (P =0.04) were significantly less in MISS eye. At 6 weeks, only redness (P =0.04) and TIS (P =0.05) were significantly less. Conclusion: MISS is more comfortable in the immediate post-operative period and provides better cosmesis in the intermediate period. PMID:24088635

Lifelong Learning: Characteristics, Skills, and Activities for a Business College Curriculum

ERIC Educational Resources Information Center

Love, Douglas

2011-01-01

The literature places great importance on lifelong learning, but leaves its meaning open to a wide range of interpretations. Much is written about lifelong learning after leaving school with little about business college preparation of lifelong learners. This is the departure point for the study's providing one college's operational definition of…

75 FR 22150 - Certificate of Alternative Compliance for the Ferry Boat CHARLEVOIX

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-27

... hours will cause permanent hearing damage. The crew on the ferry boat CHARLEVOIX works eight hour shifts... at the required decibel level prior to each departure (approximately every 5.3 minutes, in a 16 hour period/7 days per week operation) would subject the crew and passengers to unacceptable decibel levels...

Family Makeover: Coaching, Confession and Parental Responsibilisation

ERIC Educational Resources Information Center

Dahlstedt, Magnus; Fejes, Andreas

2014-01-01

Today, there is a widespread idea that parents need to learn how to carry out their roles as parents. Practices of parental learning operate throughout society. This article deals with one particular practice of parental learning, namely nanny TV, and the way in which ideal parents are constructed through such programmes. The point of departure is…

AirSea Battle: A Point-of-Departure Operational Concept

DTIC Science & Technology

2010-01-01

UCAS. 105 Such aircraft would be the preferred means. Their employment would help to conserve SSN tor- pedoes , which are key to keeping US and allied...does not prize efficient use of bandwidth, resulting in a certain mental laxness. For example, consider the high demand for full-motion video for non

46 CFR 78.17-22 - Verification of vessel compliance with applicable stability requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... stability requirements. 78.17-22 Section 78.17-22 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS OPERATIONS Tests, Drills, and Inspections § 78.17-22 Verification of vessel compliance with applicable stability requirements. (a) After loading and prior to departure and at all other...

46 CFR 78.17-22 - Verification of vessel compliance with applicable stability requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... stability requirements. 78.17-22 Section 78.17-22 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS OPERATIONS Tests, Drills, and Inspections § 78.17-22 Verification of vessel compliance with applicable stability requirements. (a) After loading and prior to departure and at all other...

46 CFR 78.17-22 - Verification of vessel compliance with applicable stability requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... stability requirements. 78.17-22 Section 78.17-22 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS OPERATIONS Tests, Drills, and Inspections § 78.17-22 Verification of vessel compliance with applicable stability requirements. (a) After loading and prior to departure and at all other...

14 CFR 380.32 - Specific requirements for operator-participant contracts.

Code of Federal Regulations, 2011 CFR

2011-01-01

...) The tour itinerary, if any, including the name and location of the hotels, length of stay at each, and...-departure notification of a major change, the participant may reject the substituted hotel or the changed... the contract, a refund of the portion of his payment allocable to the hotel accommodations or air...

Study of Naval Air Station Operations to Reduce Fuel Consumption

DTIC Science & Technology

2014-06-01

43 1. viii 2.  Smart Refueling...be attained (Klabjan, Johnson, Nemhouser, Gelman, & Ramaswamy, 2002). Dunbar et al. introduce a slack variable to the problem and change the...objective to minimize total cost associated with propagated delay rather than maximizing profit. The slack between an arrival and subsequent departure is

Upgraded FAA Airfield Capacity Model. Volume 2. Technical Description of Revisions

DTIC Science & Technology

1981-02-01

the threshold t k a the time at which departure k is released FIGURE 3-1 TIME AXIS DIAGRAM OF SINGLE RUNWAY OPERATIONS 3-2 J"- SIGMAR the standard...standard deviation of the interarrival time. SIGMAR - the standard deviation of the arrival runway occupancy time. A-5 SINGLE - program subroutine for

14 CFR 380.32 - Specific requirements for operator-participant contracts.

Code of Federal Regulations, 2010 CFR

2010-01-01

...) The tour itinerary, if any, including the name and location of the hotels, length of stay at each, and...-departure notification of a major change, the participant may reject the substituted hotel or the changed... the contract, a refund of the portion of his payment allocable to the hotel accommodations or air...

The Physics of Traffic Congestion and Road Pricing in Transportation Planning

NASA Astrophysics Data System (ADS)

Levinson, David

2010-03-01

This presentation develops congestion theory and congestion pricing theory from its micro- foundations, the interaction of two or more vehicles. Using game theory, with a two- player game it is shown that the emergence of congestion depends on the players' relative valuations of early arrival, late arrival, and journey delay. Congestion pricing can be used as a cooperation mechanism to minimize total costs (if returned to the players). The analysis is then extended to the case of the three- player game, which illustrates congestion as a negative externality imposed on players who do not themselves contribute to it. A multi-agent model of travelers competing to utilize a roadway in time and space is presented. To realize the spillover effect among travelers, N-player games are constructed in which the strategy set includes N+1 strategies. We solve the N-player game (for N = 7) and find Nash equilibria if they exist. This model is compared to the bottleneck model. The results of numerical simulation show that the two models yield identical results in terms of lowest total costs and marginal costs when a social optimum exists. Moving from temporal dynamics to spatial complexity, using consistent agent- based techniques, we model the decision-making processes of users and infrastructure owner/operators to explore the welfare consequence of price competition, capacity choice, and product differentiation on congested transportation networks. Component models include: (1) An agent-based travel demand model wherein each traveler has learning capabilities and unique characteristics (e.g. value of time); (2) Econometric facility provision cost models; and (3) Representations of road authorities making pricing and capacity decisions. Different from small-network equilibrium models in prior literature, this agent- based model is applicable to pricing and investment analyses on large complex networks. The subsequent economic analysis focuses on the source, evolution, measurement, and impact of product differentiation with heterogeneous users on a mixed ownership network (with tolled and untolled roads). Two types of product differentiation in the presence of toll roads, path differentiation and space differentiation, are defined and measured for a base case and several variants with different types of price and capacity competition and with various degrees of user heterogeneity. The findings favor a fixed-rate road pricing policy compared to complete pricing freedom on toll roads. It is also shown that the relationship between net social benefit and user heterogeneity is not monotonic on a complex network with toll roads.

77 FR 44140 - Drawbridge Operation Regulation; Sturgeon Bay Ship Canal, Sturgeon Bay, WI

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-27

... Maple-Oregon Bridges so vehicular traffic congestion would not develop on downtown Sturgeon Bay streets... movement of vehicular traffic in Sturgeon Bay. The Sturgeon Bay Ship Canal is approximately 8.6 miles long... significant increase in vehicular and vessel traffic during the peak tourist and navigation season between...

76 FR 56638 - Safety Zone; Head of the Cuyahoga, Cuyahoga River, Cleveland, OH

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-14

... likely combination of large numbers of recreational vessels, congested waterways, and alcohol use..., 81.40'50'' W (Marathon Bend) to a line drawn perpendicular to each river bank at 41.29'56'' N, 81.42... standards are technical standards (e.g., specifications of materials, performance, design, or operation...

A high risk critical mitral valve stenosis with emergency management at Apollo Hospitals Dhaka.

PubMed

Zahangir, N M; Hoque, K Z; Khan, M H; Haque, M A; Haider, M Z

2013-10-01

Heart valve surgery in high-risk patients with severe jaundice, congestive hepatomegaly and renal impairment is associated with considerable morbidity and mortality. Without operation the consequences are invariably grave. A 35 years old gentleman with congestive cardiac failure was initially treated in coronary care unit (CCU). Mitral valve area was 0.5cm², pulmonary arterial systolic pressure (PASP) was 110mmHg, serum bilirubin was 20mg/dl, SGPT & SGOT were 1024iu/l and 1027iu/l respectively. Serum creatinine was 3.35mmol/l. Serum bilirubin gradually diminished to 3.1mg/dl after 12 days treatment in Coronary Care Unit but next day it increased to 3.6mg/dl. Mitral valve was replaced on an emergency basis. Echocardiogram on the 5th post operative day showed well functioning prosthetic mitral valve in situ. Serum bilirubin decreased to 2.2mg/dl, SGPT, SGOT and serum creatinine to 43iu/l, 40iu/l and 1.34mmol/l respectively. After 8 weeks of postoperative follow up his serum bilirubin decreased to 0.8mg/dl.

Effect of Surface Traffic Count on Taxi Time at Dallas-Fort Worth (DFW) International Airport

NASA Technical Reports Server (NTRS)

Kistler, Matthew Stephen; Gupta, Gautam

2008-01-01

As the amount of air traffic increases over the years, most airports simply do not have the means of expanding to handle the intensified traffic on the surface that will ensue. Precise surveillance equipment and automation concepts, as well as advanced surface traffic algorithms are being developed to improve airport efficiency. These surface algorithms require inputs unique to each airport to ensure maximum efficiency, and minimal taxi delay. This study analyzes surface traffic at Dallas-Fort Worth International Airport (DFW) to determine the effect of the number of aircraft on the surface and the amount of stop and go situations they experience to the amount of additional taxi time encountered. If the surface capacity of an airport is known, minimal delay can be accomplished by limiting the number of taxiing aircraft to that capacity. This concept is related to highways, where traffic flow drastically decreases as more cars occupy the road. An attempt to minimize this effect on highways is seen with the use of metering lights at freeway on-ramps. Since the surface traffic at airports is highly regulated, and aircraft are less mobile on the ground, limiting the surface count to a certain number can greatly reduce the amount of additional taxi time encountered, as well as reduce hazardous emissions. This study will also find the regions of an airport that encounter the most additional taxi time when the number of aircraft in that area is increased. This could help surface traffic algorithms avoid congesting that area, or re-route aircraft to different runways when that area reaches its capacity. The relationship between the amount of stop and go situations an aircraft encounters and their effect on the taxi time of that aircraft will also be investigated. This will help to determine the effect of holding an aircraft on the taxiway as opposed to re-routing it. The lesser of the two should be used when developing surface traffic algorithms to further minimize the delay encountered. The fields investigated in this study include taxi time, the number of aircraft on the surface, the number of stop and go situations, and the time stopped for each aircraft. Taxi time is defined as spot to runway for departures, and runway to spot for arrivals. It does not include ramp area taxi time because the ramp area is controlled differently, and surface traffic schedulers do not currently incorporate them. Taxi time is found by finding the difference between take-off time (OFF) and spot crossing time for departures, and spot crossing time and landing time (ON) for arrivals. All surface data was either found directly using the Surface Operations Data Analysis and Adaptation (SODAA), a tool to analyze the Surface Management System (SMS) generated log files, or indirectly from SODAA using Matlab to derive values from SODAA data. The number of aircraft on the surface is found by looping through the ON times, OFF times, and spot times for each aircraft during a particular day. For each departure aircraft, surface counts are taken at its spot crossing and OFF time. The average of these two is used as the surface count for that aircraft. For arrivals, surface counts are taken at its ON time and its spot crossing time. The average of these two is used.

Contemporary approaches to congestion pricing : lessons learned from the national evaluation of congestion pricing strategies at six sites.

DOT National Transportation Integrated Search

2015-08-01

This document represents the final report of the national evaluation of congestion reduction strategies at six sites that received federal funding under the Urban Partnership Agreement (UPA) and Congestion Reduction Demonstration (CRD) programs. The ...

Mobility and the costs of congestion in New Jersey : 2001 update

DOT National Transportation Integrated Search

2001-07-01

The objective of the Mobility and the Costs of Congestion study is to measure quantifiable and qualitative impacts of roadway congestion in New Jersey. The study addresses the impacts of congestion on an average traveler or affected person, as well a...

Diagnosis and management of nasal congestion: the role of intranasal corticosteroids.

PubMed

Benninger, Michael

2009-01-01

Nasal congestion is considered the most bothersome of allergic rhinitis (AR) symptoms and can significantly impair ability to function at work, home, and school. Effective management of AR-related nasal congestion depends on accurate diagnosis and appropriate treatment. Many individuals with AR and AR-related congestion remain undiagnosed and do not receive prescription medication. However, new tools intended to improve the diagnosis of nasal congestion have been developed and validated. Intranasal corticosteroids (INSs) are recommended as first-line therapy for patients with moderate-to-severe AR and also when nasal congestion is a prominent symptom. Double blind, randomized clinical trials have demonstrated greater efficacy of INSs versus placebo, antihistamines, or montelukast for relief of all nasal symptoms, especially congestion. Patient adherence to treatment also affects outcomes, and this may be influenced by patient preferences for the sensory attributes of an individual drug. Increased awareness of the effects of AR-related nasal congestion, the efficacy and safety of available pharmacotherapies, and barriers to adherence may improve clinical outcomes.

Signalling and obfuscation for congestion control

NASA Astrophysics Data System (ADS)

Mareček, Jakub; Shorten, Robert; Yu, Jia Yuan

2015-10-01

We aim to reduce the social cost of congestion in many smart city applications. In our model of congestion, agents interact over limited resources after receiving signals from a central agent that observes the state of congestion in real time. Under natural models of agent populations, we develop new signalling schemes and show that by introducing a non-trivial amount of uncertainty in the signals, we reduce the social cost of congestion, i.e., improve social welfare. The signalling schemes are efficient in terms of both communication and computation, and are consistent with past observations of the congestion. Moreover, the resulting population dynamics converge under reasonable assumptions.

Improving Explicit Congestion Notification with the Mark-Front Strategy

NASA Technical Reports Server (NTRS)

Liu, Chunlei; Jain, Raj

2001-01-01

Delivering congestion signals is essential to the performance of networks. Current TCP/IP networks use packet losses to signal congestion. Packet losses not only reduces TCP performance, but also adds large delay. Explicit Congestion Notification (ECN) delivers a faster indication of congestion and has better performance. However, current ECN implementations mark the packet from the tail of the queue. In this paper, we propose the mark-front strategy to send an even faster congestion signal. We show that mark-front strategy reduces buffer size requirement, improves link efficiency and provides better fairness among users. Simulation results that verify our analysis are also presented.

Vortex-Free Flight Corridors for Aircraft Executing Compressed Landing Operations

NASA Technical Reports Server (NTRS)

Rossow, Vernon J.

2006-01-01

A factor that limits airport arrival and departure rates is the need to wait between operations for the wake vortices of preceding aircraft to decay to a safe level. As airport traffic demand increases, creative methods will be needed to overcome the limitations caused by the hazard posed by vortex wakes so that airport capacities can be increased. The problem addressed here is the design of vortex-free trajectories for aircraft as they fly from their cruise altitudes down to their final approach paths and to a landing. The guidelines presented recommend that the flight path of each aircraft in a group executing nearly-simultaneous landings be spaced far enough apart laterally along organized flight paths so that the vortex wakes of preceding aircraft will not intrude into the airspace to be used by following aircraft. An example is presented as to how a combination of straight lines and circular arcs is able to provide each aircraft in a group with a vortex-free trajectory so that all are able to safely form the pattern needed for nearly simultaneous landings on a set of closely-spaced parallel runways. Although the guidelines me described for aircraft on approach, they are also applicable to departure, and to en route operations.

23 CFR 971.214 - Federal lands congestion management system (CMS).

Code of Federal Regulations, 2011 CFR

2011-04-01

... congestion management strategies; (v) Determine methods to monitor and evaluate the performance of the multi... Federal lands congestion management system (CMS). (a) For purposes of this section, congestion means the... for the transportation systems providing access to and within National Forests, as appropriate, that...

23 CFR 970.214 - Federal lands congestion management system (CMS).

Code of Federal Regulations, 2014 CFR

2014-04-01

... 23 Highways 1 2014-04-01 2014-04-01 false Federal lands congestion management system (CMS). 970... LANDS HIGHWAYS NATIONAL PARK SERVICE MANAGEMENT SYSTEMS National Park Service Management Systems § 970.214 Federal lands congestion management system (CMS). (a) For purposes of this section, congestion...

APPLICATION OF TRAVEL TIME RELIABILITY FOR PERFORMANCE ORIENTED OPERATIONAL PLANNING OF EXPRESSWAYS

NASA Astrophysics Data System (ADS)

Mehran, Babak; Nakamura, Hideki

Evaluation of impacts of congestion improvement scheme s on travel time reliability is very significant for road authorities since travel time reliability repr esents operational performance of expressway segments. In this paper, a methodology is presented to estimate travel tim e reliability prior to implementation of congestion relief schemes based on travel time variation modeling as a function of demand, capacity, weather conditions and road accident s. For subject expressway segmen ts, traffic conditions are modeled over a whole year considering demand and capacity as random variables. Patterns of demand and capacity are generated for each five minute interval by appl ying Monte-Carlo simulation technique, and accidents are randomly generated based on a model that links acci dent rate to traffic conditions. A whole year analysis is performed by comparing de mand and available capacity for each scenario and queue length is estimated through shockwave analysis for each time in terval. Travel times are estimated from refined speed-flow relationships developed for intercity expressways and buffer time index is estimated consequently as a measure of travel time reliability. For validation, estimated reliability indices are compared with measured values from empirical data, and it is shown that the proposed method is suitable for operational evaluation and planning purposes.

23 CFR 450.320 - Congestion management process in transportation management areas.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 23 Highways 1 2014-04-01 2014-04-01 false Congestion management process in transportation... Programming § 450.320 Congestion management process in transportation management areas. (a) The transportation planning process in a TMA shall address congestion management through a process that provides for safe and...

23 CFR 450.320 - Congestion management process in transportation management areas.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 23 Highways 1 2011-04-01 2011-04-01 false Congestion management process in transportation... Programming § 450.320 Congestion management process in transportation management areas. (a) The transportation planning process in a TMA shall address congestion management through a process that provides for safe and...

23 CFR 450.320 - Congestion management process in transportation management areas.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 23 Highways 1 2013-04-01 2013-04-01 false Congestion management process in transportation... Programming § 450.320 Congestion management process in transportation management areas. (a) The transportation planning process in a TMA shall address congestion management through a process that provides for safe and...

76 FR 75875 - Plan for Conduct of 2012 Electric Transmission Congestion Study

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-05

... DEPARTMENT OF ENERGY Plan for Conduct of 2012 Electric Transmission Congestion Study AGENCY... preparation of a study of electric transmission congestion pursuant to section 216(a)(1) of the Federal Power...-register at this Web site: http://energy.gov/oe/congestion-study-2012 . [[Page 75876

Aircraft Energy Conservation during Airport Ground Operations

DTIC Science & Technology

1982-03-01

minimized. The model can be run in a non -optimizing mode to simulate movements along pre-assigned taxi paths. 8-6 The model is also designed ...5.5 5.6 5.7 Engine Designation by Airline and Aircraft Type IAD 2-6 Engine Designation by Airline and Aircraft Type DCA 2-7 Fuel Flow Rates...B.2 CY 1979 Aircraft Operations at IAD and DCA Airports . . 3-5 B.3 1979 Scheduled and Non -Scheduled Departures from IAD by Aircraft Type and

Isolated torsion of fallopian tube during pregnancy; report of two cases.

PubMed

Yalcin, O T; Hassa, H; Zeytinoglu, S; Isiksoy, S

1997-08-01

Isolated torsion of fallopian tube is very uncommon during pregnancy. Predisposing factors for torsion are hydrosalpinx, prior tubal operation, pelvic congestion, ovarian and paraovarian masses and trauma. Although the most important clinical symptom is abdominal pain in lower quadrants, the diagnosis is usually established during the operation performed for acute abdomen and salpingectomy is almost always necessary. Two cases of torsion of fallopian tube during pregnancy, one with hydrosalpinx, the other with paratubal cyst are presented and symptoms and predisposing factors are discussed.

8 CFR 251.5 - Paper arrival and departure manifests for crew.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 8 Aliens and Nationality 1 2011-01-01 2011-01-01 false Paper arrival and departure manifests for... REGULATIONS ARRIVAL AND DEPARTURE MANIFESTS AND LISTS: SUPPORTING DOCUMENTS § 251.5 Paper arrival and... from the United States must submit arrival and departure manifests in a paper format in accordance with...

Autonomous Congestion Control in Delay-Tolerant Networks

NASA Technical Reports Server (NTRS)

Burleigh, Scott; Jennings, Esther; Schoolcraft, Joshua

2006-01-01

Congestion control is an important feature that directly affects network performance. Network congestion may cause loss of data or long delays. Although this problem has been studied extensively in the Internet, the solutions for Internet congestion control do not apply readily to challenged network environments such as Delay Tolerant Networks (DTN) where end-to-end connectivity may not exist continuously and latency can be high. In DTN, end-to-end rate control is not feasible. This calls for congestion control mechanisms where the decisions can be made autonomously with local information only. We use an economic pricing model and propose a rule-based congestion control mechanism where each router can autonomously decide on whether to accept a bundle (data) based on local information such as available storage and the value and risk of accepting the bundle (derived from historical statistics). Preliminary experimental results show that this congestion control mechanism can protect routers from resource depletion without loss of data.

A research of the community’s opening to the outside world

NASA Astrophysics Data System (ADS)

Xu, Lan; Liu, Xiangzhuo

2017-03-01

Closed residential areas, called community, the traffic network and result in various degrees of traffic congestion such as amputating, dead ends and T-shaped roads. In order to reveal the mechanism of the congestion, establish an effective evaluation index system and finally provide theoretical basis for the study of traffic congestion, we have done researches on factors for traffic congestion and have established a scientific evaluation index system combining experiences home and abroad, based on domestic congestion status. Firstly, we analyse the traffic network as the entry point, and then establish the evaluation model of road capacity with the method of AHP index system. Secondly, we divide the condition of urban congestion into 5 levels from congestion to smoothness. Besides, with VISSIM software, simulations about traffic capacity before and after community opening are carried out. Finally, we provide forward reasonable suggestions upon the combination of models and reality.

Passenger Flow Forecasting Research for Airport Terminal Based on SARIMA Time Series Model

NASA Astrophysics Data System (ADS)

Li, Ziyu; Bi, Jun; Li, Zhiyin

2017-12-01

Based on the data of practical operating of Kunming Changshui International Airport during2016, this paper proposes Seasonal Autoregressive Integrated Moving Average (SARIMA) model to predict the passenger flow. This article not only considers the non-stationary and autocorrelation of the sequence, but also considers the daily periodicity of the sequence. The prediction results can accurately describe the change trend of airport passenger flow and provide scientific decision support for the optimal allocation of airport resources and optimization of departure process. The result shows that this model is applicable to the short-term prediction of airport terminal departure passenger traffic and the average error ranges from 1% to 3%. The difference between the predicted and the true values of passenger traffic flow is quite small, which indicates that the model has fairly good passenger traffic flow prediction ability.

A Method for Scheduling Air Traffic with Uncertain En Route Capacity Constraints

NASA Technical Reports Server (NTRS)

Arneson, Heather; Bloem, Michael

2009-01-01

A method for scheduling ground delay and airborne holding for flights scheduled to fly through airspace with uncertain capacity constraints is presented. The method iteratively solves linear programs for departure rates and airborne holding as new probabilistic information about future airspace constraints becomes available. The objective function is the expected value of the weighted sum of ground and airborne delay. In order to limit operationally costly changes to departure rates, they are updated only when such an update would lead to a significant cost reduction. Simulation results show a 13% cost reduction over a rough approximation of current practices. Comparison between the proposed as needed replanning method and a similar method that uses fixed frequency replanning shows a typical cost reduction of 1% to 2%, and even up to a 20% cost reduction in some cases.

Transnational Discourses of Knowledge and Learning in Professional Work: Examples from Computer Engineering

ERIC Educational Resources Information Center

Nerland, Monika

2010-01-01

Taking a Foucauldian framework as its point of departure, this paper discusses how transnational discourses of knowledge and learning operate in the profession of computer engineering and form a certain logic through which modes of being an engineer are regulated. Both the knowledge domain of computer engineering and its related labour market is…

77 FR 53249 - Agency Information Collection Activities: Requests for Comments; Clearance of New Approval of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-31

... International Airport (JFK), Newark Liberty International Airport (EWR), and LaGuardia Airport (LGA). The FAA... allocate arrival and departure slots at JFK, EWR, and LGA. The designations resulted in part from... operational growth at ORD and SFO. The information is reported to the FAA by carriers holding a slot at JFK...

78 FR 9449 - Noise Exposure Map Notice, Southwest Florida International Airport, Fort Myers, FL

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-08

... Use Percentages; Table 7.9, 2011 and 2017 Departure Flight Track Use Percentages; Table 7.10, 2011 and 2017 Arrival Flight Track Use Percentages; Table 7.11, 2011 and 2017 Local (Touch and Go) Flight Track...; Figure 5-3, Monthly Operations; Figure 7.1, Modeled Flight Tracks--Northeast Flow; Figure 7.2, Modeled...

Enhanced Flight Vision Systems Operational Feasibility Study Using Radar and Infrared Sensors

NASA Technical Reports Server (NTRS)

Etherington, Timothy J.; Kramer, Lynda J.; Severance, Kurt; Bailey, Randall E.; Williams, Steven P.; Harrison, Stephanie J.

2015-01-01

Approach and landing operations during periods of reduced visibility have plagued aircraft pilots since the beginning of aviation. Although techniques are currently available to mitigate some of the visibility conditions, these operations are still ultimately limited by the pilot's ability to "see" required visual landing references (e.g., markings and/or lights of threshold and touchdown zone) and require significant and costly ground infrastructure. Certified Enhanced Flight Vision Systems (EFVS) have shown promise to lift the obscuration veil. They allow the pilot to operate with enhanced vision, in lieu of natural vision, in the visual segment to enable equivalent visual operations (EVO). An aviation standards document was developed with industry and government consensus for using an EFVS for approach, landing, and rollout to a safe taxi speed in visibilities as low as 300 feet runway visual range (RVR). These new standards establish performance, integrity, availability, and safety requirements to operate in this regime without reliance on a pilot's or flight crew's natural vision by use of a fail-operational EFVS. A pilot-in-the-loop high-fidelity motion simulation study was conducted at NASA Langley Research Center to evaluate the operational feasibility, pilot workload, and pilot acceptability of conducting straight-in instrument approaches with published vertical guidance to landing, touchdown, and rollout to a safe taxi speed in visibility as low as 300 feet RVR by use of vision system technologies on a head-up display (HUD) without need or reliance on natural vision. Twelve crews flew various landing and departure scenarios in 1800, 1000, 700, and 300 RVR. This paper details the non-normal results of the study including objective and subjective measures of performance and acceptability. The study validated the operational feasibility of approach and departure operations and success was independent of visibility conditions. Failures were handled within the lateral confines of the runway for all conditions tested. The fail-operational concept with pilot in the loop needs further study.

Study of quiet turbofan STOL aircraft for short haul transportation

NASA Technical Reports Server (NTRS)

Higgins, T. P.; Stout, E. G.; Sweet, H. S.

1973-01-01

Conceptual designs of Quiet Turbofan STOL Short-Haul Transport Aircraft for the mid-1980 time period are developed and analyzed to determine their technical, operational, and economic feasibility. A matrix of aircraft using various high-lift systems and design parameters are considered. Variations in aircraft characteristics, airport geometry and location, and operational techniques are analyzed systematically to determine their effects on the market, operating economics, and community acceptance. In these studies, the total systems approach is considered to be critically important in analyzing the potential of STOL aircraft to reduce noise pollution and alleviate the increasing air corridor and airport congestion.

Study of quiet turbofan STOL aircraft for short-haul transportation. Volume 1: Summary

NASA Technical Reports Server (NTRS)

1974-01-01

Conceptual designs of Quiet Turbofan STOL Short-Haul Transport Aircraft for the mid-1980 time period are developed and analyzed to determine their technical, operational, and economic feasibility. A matrix of aircraft using various high-lift systems and design parameters are considered. Variations in aircraft characteristics, airport geometry and location, and operational techniques are analyzed systematically to determine their effects on the market, operating economics, and community acceptance. The total systems approach is considered to be critically important in analyzing the potential of STOL aircraft to reduce noise pollution and alleviate the increasing air corridor and airport congestion.

The safety potential of lane departure warning systems-A descriptive real-world study of fatal lane departure passenger car crashes in Sweden.

PubMed

Sternlund, Simon

2017-05-29

Lane departure crashes account for a significant proportion of passenger car occupant fatalities and serious injuries. Utilizing real-world data involving fatal passenger car crashes in Sweden, the characteristics of lane departure crashes were identified and the safety potential of lane departure warning (LDW) systems was quantified. The material consisted of 104 in-depth studies of fatal passenger car crashes in 2010. The crashes were classified as single-vehicle (n = 48), head-on (n = 52), and overtaking (n = 4) crashes. These crash types were identified as crashes that could have potentially involved lane departure. A case-by-case analysis was carried out and lane departure crashes were identified and characterized using police reports and information collected by crash investigators at the Swedish Transport Administration; for example, inspections and photographs of the crash sites and of the involved vehicles. Lane departure crashes were separated from crashes where loss of control occurred pre-lane departure. Furthermore, loss of control post-lane departures were identified. When studying the pre-stage of lane departure without prior loss of control, crashes were categorized as unintentional drifting, intentional lane change, or evasive maneuver. Using previously published effectiveness information, the potential for LDW systems to prevent crashes was estimated. Of all crashes with passenger car occupant fatalities in Sweden in 2010, 46% (63/138) were found to relate to lane departure without prior loss of control. These crashes accounted for 61% (63/104) of all single-vehicle, head-on, and overtaking crashes. The remaining 41 crashes were due to loss of control pre-lane departure. Unintentional drifting accounted for 81% (51/63) of all lane departure crashes without prior loss of control, which corresponded to 37% (51/138) of all fatal passenger car occupant crashes. LDW systems were found to potentially prevent 33-38 of the 100 fatal head-on and single vehicle crashes. These crashes involved drifting and occurred on roads with visible lane markings, signed posted speed limits ≥70 km/h, and without rumble strips on the corresponding lane departure side. The range of potentially prevented crashes (33-38) is due to the inclusion or exclusion of crashes involving excessive speeding. In this study, approximately half (51/100) of all head-on and single-vehicle crashes were identified as being a consequence of drifting, where LDW systems had the potential to prevent the majority (33-38) of these crashes. The typical lane departure crash without prior loss of control occurred on undivided roads in rural areas with signed posted speed limits ≥70 km/h, where the center and side road markings were visible.

Pulmonary edema

MedlinePlus

... congestion; Lung water; Pulmonary congestion; Heart failure - pulmonary edema ... Pulmonary edema is often caused by congestive heart failure . When the heart is not able to pump efficiently, blood ...

14 CFR 93.28 - One-for-one trade of Arrival Authorizations.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false One-for-one trade of Arrival Authorizations. 93.28 Section 93.28 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Congestion and Delay Reduction at Chicago O'Hare International...

A resilience-oriented approach for quantitatively assessing recurrent spatial-temporal congestion on urban roads.

PubMed

Tang, Junqing; Heinimann, Hans Rudolf

2018-01-01

Traffic congestion brings not only delay and inconvenience, but other associated national concerns, such as greenhouse gases, air pollutants, road safety issues and risks. Identification, measurement, tracking, and control of urban recurrent congestion are vital for building a livable and smart community. A considerable amount of works has made contributions to tackle the problem. Several methods, such as time-based approaches and level of service, can be effective for characterizing congestion on urban streets. However, studies with systemic perspectives have been minor in congestion quantification. Resilience, on the other hand, is an emerging concept that focuses on comprehensive systemic performance and characterizes the ability of a system to cope with disturbance and to recover its functionality. In this paper, we symbolized recurrent congestion as internal disturbance and proposed a modified metric inspired by the well-applied "R4" resilience-triangle framework. We constructed the metric with generic dimensions from both resilience engineering and transport science to quantify recurrent congestion based on spatial-temporal traffic patterns and made the comparison with other two approaches in freeway and signal-controlled arterial cases. Results showed that the metric can effectively capture congestion patterns in the study area and provides a quantitative benchmark for comparison. Also, it suggested not only a good comparative performance in measuring strength of proposed metric, but also its capability of considering the discharging process in congestion. The sensitivity tests showed that proposed metric possesses robustness against parameter perturbation in Robustness Range (RR), but the number of identified congestion patterns can be influenced by the existence of ϵ. In addition, the Elasticity Threshold (ET) and the spatial dimension of cell-based platform differ the congestion results significantly on both the detected number and intensity. By tackling this conventional problem with emerging concept, our metric provides a systemic alternative approach and enriches the toolbox for congestion assessment. Future work will be conducted on a larger scale with multiplex scenarios in various traffic conditions.

Analysis of random drop for gateway congestion control. M.S. Thesis

NASA Technical Reports Server (NTRS)

Hashem, Emam Salaheddin

1989-01-01

Lately, the growing demand on the Internet has prompted the need for more effective congestion control policies. Currently No Gateway Policy is used to relieve and signal congestion, which leads to unfair service to the individual users and a degradation of overall network performance. Network simulation was used to illustrate the character of Internet congestion and its causes. A newly proposed gateway congestion control policy, called Random Drop, was considered as a promising solution to the pressing problem. Random Drop relieves resource congestion upon buffer overflow by choosing a random packet from the service queue to be dropped. The random choice should result in a drop distribution proportional to the bandwidth distribution among all contending TCP connections, thus applying the necessary fairness. Nonetheless, the simulation experiments demonstrate several shortcomings with this policy. Because Random Drop is a congestion control policy, which is not applied until congestion has already occurred, it usually results in a high drop rate that hurts too many connections including well-behaved ones. Even though the number of packets dropped is different from one connection to another depending on the buffer utilization upon overflow, the TCP recovery overhead is high enough to neutralize these differences, causing unfair congestion penalties. Besides, the drop distribution itself is an inaccurate representation of the average bandwidth distribution, missing much important information about the bandwidth utilization between buffer overflow events. A modification of Random Drop to do congestion avoidance by applying the policy early was also proposed. Early Random Drop has the advantage of avoiding the high drop rate of buffer overflow. The early application of the policy removes the pressure of congestion relief and allows more accurate signaling of congestion. To be used effectively, algorithms for the dynamic adjustment of the parameters of Early Random Drop to suite the current network load must still be developed.

Disturbance departure and fragmentation of natural systems in the interior Columbia basin.

Treesearch

Wendel J. Hann; Michael J. Wisdom; Mary M. Rowland

2003-01-01

We integrated landscape data from science assessments of the interior Columbia basin (basin) into one variable that functions as a robust index of departure from native conditions. This variable, referred to as the disturbance departure and fragmentation index, is a spatially explicit measure of landscape quality and resiliency. Primary causes of departure and...

Arrival and Departure Patterns of Public Sector Employees before and after Implementation of Flexitime.

ERIC Educational Resources Information Center

Ronen, Simcha

1981-01-01

Examined the effects of a flexible working hours schedule on the arrival and departure times of 162 public sector employees. Results indicated that workers, when scheduling their own workday, deviate only moderately from their preflexitime arrival/departure times; and they tend to develop relatively stable arrival/departure patterns. (Author/RC)

Characterizing Longitude-Dependent Orbital Debris Congestion in the Geosynchronous Orbit Regime

NASA Astrophysics Data System (ADS)

Anderson, Paul V.

The geosynchronous orbit (GEO) is a unique commodity of the satellite industry that is becoming increasingly contaminated with orbital debris, but is heavily populated with high-value assets from the civil, commercial, and defense sectors. The GEO arena is home to hundreds of communications, data transmission, and intelligence satellites collectively insured for an estimated 18.3 billion USD. As the lack of natural cleansing mechanisms at the GEO altitude renders the lifetimes of GEO debris essentially infinite, conjunction and risk assessment must be performed to safeguard operational assets from debris collisions. In this thesis, longitude-dependent debris congestion is characterized by predicting the number of near-miss events per day for every longitude slot at GEO, using custom debris propagation tools and a torus intersection metric. Near-miss events with the present-day debris population are assigned risk levels based on GEO-relative position and speed, and this risk information is used to prioritize the population for debris removal target selection. Long-term projections of debris growth under nominal launch traffic, mitigation practices, and fragmentation events are also discussed, and latitudinal synchronization of the GEO debris population is explained via node variations arising from luni-solar gravity. In addition to characterizing localized debris congestion in the GEO ring, this thesis further investigates the conjunction risk to operational satellites or debris removal systems applying low-thrust propulsion to raise orbit altitude at end-of-life to a super-synchronous disposal orbit. Conjunction risks as a function of thrust level, miss distance, longitude, and semi-major axis are evaluated, and a guidance method for evading conjuncting debris with continuous thrust by means of a thrust heading change via single-shooting is developed.

Medical reasons behind player departures from male and female professional tennis competitions.

PubMed

Okholm Kryger, Katrine; Dor, Frédéric; Guillaume, Marion; Haida, Amal; Noirez, Philippe; Montalvan, Bernard; Toussaint, Jean-François

2015-01-01

The number of retirements, withdrawals, and "lucky losers" (the replacement of a player who withdraws before the start of the tournament by a losing player from the qualifying round) from professional tennis tournaments has increased, but the reasons behind such departures have not yet been analyzed. An official consensus statement has been conducted to allow a general categorization of injuries in tennis. To determine the reasons for departure and injury rates in professional tennis. Descriptive epidemiology study. All reasons for departures were collected from official Association of Tennis Professionals (ATP) and Women's Tennis Association (WTA) web pages. All tournaments apart from the 4 major competitions (the Australian Open, French Open, Wimbledon, and US Open) were included for the period 2001-2012 for men and women. Personal data, tournament information, surface, match setting, date, and reason were obtained for each departure scenario. Variations in departure and injury rates were seen throughout the season. Women left and were injured significantly more than men. Women mainly left because of thigh injuries, whereas men left mainly because of back injuries. Playing surface only had an influence on the risk of lower back injuries. Only women's departures were affected by the tournament round. A high number of departures from tournaments have occurred during the past 10 years on the ATP and WTA circuits. Injuries were the main reasons of these departures, regardless of the type of departure and player sex. The back and thigh were the main locations of injuries for men and women, respectively. © 2014 The Author(s).