A generic approach for examining the effectiveness of traffic control devices in school zones.

PubMed

Zhao, Xiaohua; Li, Jiahui; Ding, Han; Zhang, Guohui; Rong, Jian

2015-09-01

The effectiveness and performance of traffic control devices in school zones have been impacted significantly by many factors, such as driver behavioral attributes, roadway geometric features, environmental characteristics, weather and visibility conditions, region-wide traffic regulations and policies, control modes, etc. When deploying traffic control devices in school zones, efforts are needed to clarify: (1) whether traffic control device installation is warranted; and (2) whether other device effectively complements this traffic control device and strengthens its effectiveness. In this study, a generic approach is developed to examine and evaluate the effectiveness of various traffic control devices deployed in school zones through driving simulator-based experiments. A Traffic Control Device Selection Model (TCDSM) is developed and two representative school zones are selected as the testbed in Beijing for driving simulation implementation to enhance its applicability. Statistical analyses are conducted to extract the knowledge from test data recorded by a driving simulator. Multiple measures of effectiveness (MOEs) are developed and adopted including average speed, relative speed difference, and standard deviation of acceleration for traffic control device performance quantification. The experimental tests and analysis results reveal that the appropriateness of the installation of certain traffic control devices can be statistically verified by TCDSM. The proposed approach provides a generic framework to assess traffic control device performance in school zones including experiment design, statistical formulation, data analysis, simulation model implementation, data interpretation, and recommendation development. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of temporary traffic signals in conjunction with pilot car operations at two-way long temporary work zones.

DOT National Transportation Integrated Search

2016-05-01

The primary objective of this study was to evaluate the use of Portable Traffic Signal (PTS) systems at long, rural : two-lane work zones and to compare three different conditions for controlling one-lane traffic in conjunction with pilot car : opera...

A demonstration of expert systems applications in transportation engineering : volume II, TRANZ, a prototype expert system for traffic control in highway work zones.

DOT National Transportation Integrated Search

1988-01-01

The development of a prototype knowledge-based expert system (KBES) for selecting appropriate traffic control strategies and management techniques around highway work zones was initiated. This process was encompassed by the steps that formulate the p...

Driver responses to differing urban work zone configurations.

PubMed

Morgan, J F; Duley, A R; Hancock, P A

2010-05-01

This study reports the results of a simulator-based assessment of driver response to two different urban highway work zone configurations. One configuration represented an existing design which was contrasted with a second configuration that presented a reduced taper length prototype work zone design. Twenty-one drivers navigated the two different work zones in two different conditions, one with and one without a lead vehicle; in this case a bus. Measures of driver speed, braking, travel path, and collision frequency were recorded. Drivers navigated significantly closer to the boundary of the work area in the reduced taper length design. This proximity effect was moderated by the significant interaction between lead vehicle and taper length and such interactive effects were also observed for driver speed at the end of the work zone and the number of collisions observed within the work zone itself. These results suggest that reduced taper length poses an increase in risk to both drivers and work zone personnel, primarily when driver anticipation is reduced by foreshortened viewing distances. Increase in such risk is to a degree offset by the reduction of overall exposure to the work zone that a foreshortened taper creates. The benefits and limitations to a simulation-based approach to the assessment and prediction of driver behavior in different work zone configurations are also discussed. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

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...

Air Traffic Controller Working Memory: Considerations in Air Traffic Control Tactical Operations

DTIC Science & Technology

1993-09-01

INFORMATION PROCESSING SYSTEM 3 2. AIR TRAFFIC CONTROLLER MEMORY 5 2.1 MEMORY CODES 6 21.1 Visual Codes 7 2.1.2 Phonetic Codes 7 2.1.3 Semantic Codes 8...raise an awareness of the memory re- quirements of ATC tactical operations by presenting information on working memory processes that are relevant to...working v memory permeates every aspect of the controller’s ability to process air traffic information and control live traffic. The

Evaluation of temporary traffic signals in conjunction with pilot car operations at two-way long temporary work zones : technical summary.

DOT National Transportation Integrated Search

2016-05-01

The primary objective of this study was to evaluate the use of Portable Traffic Signal (PTS) systems at long, rural two-lane work zones and to compare three different conditions for controlling one-lane traffic in conjunction with pilot car operation...

Traffic analysis toolbox volume IX : work zone modeling and simulation, a guide for analysts

DOT National Transportation Integrated Search

2009-03-01

This document is the second volume in the FHWA Traffic Analysis Toolbox: Work Zone Analysis series. Whereas the first volume provides guidance to decision-makers at agencies and jurisdictions considering the role of analytical tools in work zone plan...

Work zone and operation enhancements.

DOT National Transportation Integrated Search

2010-02-01

Oregon Department of Transportation contractors are required to implement Traffic Control Plans (TCPs) to protect and direct traffic through work zones. The design and implementation of TCPs have shown variation from project-to-project across the Sta...

Phase II, improved work zone design guidelines and enhanced model of traffic delays in work zones : executive summary report.

DOT National Transportation Integrated Search

2009-03-01

This project contains three major parts. In the first part a digital computer simulation model was developed with the aim to model the traffic through a freeway work zone situation. The model was based on the Arena simulation software and used cumula...

Speeding in highway work zone: An Evaluation of methods of speed control.

PubMed

Ravani, Bahram; Wang, Chao

2018-04-01

Highway workers frequently work in close proximity of live traffic in highway work zones, traffic accidents therefore have devastating effects on worker safety. In order to reduce the potential for such accidents, methods involving use of advisory signs and police presence have been used to mitigate accident risks and improve safety for highway workers. This research evaluates the magnitude of the speeding problem in highway work zones and the effects of four levels of police presence on improving work zone safety. Speed data were collected in six different work zone locations in northern and southern California and used to determine the magnitude and nature of speeding problem in highway work zones. In addition data were collected over 11 test-days in four work zones with four levels of police presence: radar speed display with police decal and lighting, passive use of a police vehicle with radar speed display, passive use of a police vehicle without radar speed display, and active police speed enforcement near work zones. This paper analyzes this data using statistical methods to evaluate the effectiveness of these different methods of speed control on the safety of the work zone. Four Measures of Effectiveness (MOE) were used in this evaluation consisting of average speed reduction, speed variance, 85th percentile speed, and proportion of high speed vehicles. The results indicate that all levels of police presence provided statistically significant improvements in one or more of the MOEs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Phase II, improved work zone design guidelines and enhanced model of traffic delays in work zones : final report, March 2009.

DOT National Transportation Integrated Search

2009-03-01

This project contains three major parts. In the first part a digital computer simulation model was developed with the aim to model the traffic through a freeway work zone situation. The model was based on the Arena simulation software and used cumula...

Work Zone Design and Operations Enhancements

DOT National Transportation Integrated Search

2010-02-01

Oregon Department of Transportation contractors are required to implement Traffic Control Plans (TCPs) to protect and direct traffic through work zones. The design and implementation of TCPs have shown variation from project-to-project across the Sta...

Portable traffic management system smart work zone application : operational test evaluation report

DOT National Transportation Integrated Search

1997-05-01

As part of its statewide Intelligent Transportation System (ITS), The Minnesota Department of Transportation (Mn/DOT) sponsored an operational test of the Portable Traffic Management System (PTMS) in a work zone application in cooperation with its pr...

Modeling work zone crash frequency by quantifying measurement errors in work zone length.

PubMed

Yang, Hong; Ozbay, Kaan; Ozturk, Ozgur; Yildirimoglu, Mehmet

2013-06-01

Work zones are temporary traffic control zones that can potentially cause safety problems. Maintaining safety, while implementing necessary changes on roadways, is an important challenge traffic engineers and researchers have to confront. In this study, the risk factors in work zone safety evaluation were identified through the estimation of a crash frequency (CF) model. Measurement errors in explanatory variables of a CF model can lead to unreliable estimates of certain parameters. Among these, work zone length raises a major concern in this analysis because it may change as the construction schedule progresses generally without being properly documented. This paper proposes an improved modeling and estimation approach that involves the use of a measurement error (ME) model integrated with the traditional negative binomial (NB) model. The proposed approach was compared with the traditional NB approach. Both models were estimated using a large dataset that consists of 60 work zones in New Jersey. Results showed that the proposed improved approach outperformed the traditional approach in terms of goodness-of-fit statistics. Moreover it is shown that the use of the traditional NB approach in this context can lead to the overestimation of the effect of work zone length on the crash occurrence. Copyright © 2013 Elsevier Ltd. All rights reserved.

An evaluation of school zone traffic control strategies : phase I.

DOT National Transportation Integrated Search

2013-03-01

Throughout the past six decades, the predominant mode of student transport has shifted from walkingto riding in a school bus or personal vehicle which has impacted both the safety and efficiency of school zone traffic control strategies. In order to ...

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 ...

Development of an interactive GIS based work zone traffic control tool.

DOT National Transportation Integrated Search

2013-08-01

The purpose of this study was to include consideration for intersections into the previously created GIS traffic control planning tool. Available data for making intersection control calculations were collected and integrated into the design of the t...

Determining the drivers' acceptance of EFTCD in highway work zones.

PubMed

Bai, Yong; Li, Yingfeng

2011-05-01

Traffic safety is a major concern in the temporary one-lane, two-way highway work zones due to the increasing of construction and maintenance operations. To prevent rear-end crashes and to mitigate the severity of these crashes caused by the inattentive driving, the utilization of the Emergency Flasher Traffic Control Device (EFTCD) was under consideration by government agencies, in addition to existing temporary traffic control devices installed in the one-lane, two-way highway work zones. The EFTCD was a newly proposed traffic warning device implemented through the use of vehicles' hazard warning flashers. The primary objective of the research project was to investigate the drivers' acceptance of the proposed EFTCD by measuring the mean speed changes of vehicles with and without EFTCD and by evaluating the drivers' opinions of the EFTCD using the survey method. Field experimental results revealed that the EFTCD effectively reduced the mean vehicle speeds in the upstream of two work zones. A slow speed is more likely to reduce the severity of a crash in work zones. In addition, survey results indicated that 60% of the drivers thought the EFTCD signified a need for speed reduction and 82% of drivers recommended the implementation of the EFTCD in one-lane, two-way work zones. These results provide the necessary scientific justifications for the government agencies to decide if the EFTCD should be implemented in the one-lane, two-way highway work zones to prevent rear-end crashes and to mitigate the severity of these crashes. Copyright © 2010 Elsevier Ltd. All rights reserved.

Temporary traffic control handbook, 2016 edition.

DOT National Transportation Integrated Search

2016-01-01

This handbook provides a broad, easy to understand : reference for temporary traffic control in work zones, : addressing the safe and efficient accommodation of all road : users: motorists, bicyclists, pedestrians, and those with special : needs. Whe...

Effect of flaggers and spotters in directing work zone traffic for Illinois expressways and freeways.

DOT National Transportation Integrated Search

2014-01-01

This research project focused on assessing the effectiveness and essential role of flaggers and spotters in : directing traffic for expressway and freeway work zones in Illinois with a posted speed limit greater than 40 mph. : The objectives of this ...

Work zone design and operation enhancements : final report, March 2010.

DOT National Transportation Integrated Search

2010-02-01

Oregon Department of Transportation contractors are required to implement Traffic Control Plans (TCPs) to protect and direct traffic through work zones. The design and implementation of TCPs have shown variation from project-to-project across the Sta...

Using historical crash data as part of traffic work zone safety planning and project management strategies.

DOT National Transportation Integrated Search

2014-07-01

This funding enabled the project entitled, USING HISTORICAL CRASH DATA AS PART OF TRAFFIC WORK ZONE SAFETY : PLANNING AND PROJECT MANAGEMENT STRATEGIES to address the following: : Evaluate current organizational strategies with respect to w...

Optimization of Highway Work Zone Decisions Considering Short-Term and Long-Term Impacts

DTIC Science & Technology

2010-01-01

strategies which can minimize the one-time work zone cost. Considering the complex and combinatorial nature of this optimization problem, a heuristic...combination of lane closure and traffic control strategies which can minimize the one-time work zone cost. Considering the complex and combinatorial nature ...zone) NV # the number of vehicle classes NPV $ Net Present Value p’(t) % Adjusted traffic diversion rate at time t p(t) % Natural diversion rate

Work zone positive protection guidelines for Idaho.

DOT National Transportation Integrated Search

2014-12-01

The Code of Federal Regulation (CFR) Title 23 Part 630 Subpart K - Temporary Traffic Control (630.1102630.1110) rule states : that positive protection shall be considered where work zone conditions place workers at increased risk from motorized : ...

Crash characteristics at work zones.

DOT National Transportation Integrated Search

2002-01-01

Work zones tend to cause hazardous conditions for drivers and construction workers since they generate conflicts between construction activities and traffic. A clear understanding of the characteristics of work zone crashes will enhance the selection...

Crash characteristics at work zones

DOT National Transportation Integrated Search

2001-05-01

Work zones tend to cause hazardous conditions for vehicle drivers and construction workers since they generate conflicts between construction activities and the traffic, and therefore aggravate the existing traffic conditions.

Vehicle emission implications of drivers' smart advisory system for traffic operations in work zones.

PubMed

Li, Qing; Qiao, Fengxiang; Yu, Lei

2016-05-01

Wireless communication systems have been broadly applied in various complicated traffic operations to improve mobility and safety on roads, which may raise a concern about the implication of the new technology on vehicle emissions. This paper explores how the wireless communication systems improve drivers' driving behaviors and its contributions to the emission reduction, in terms of Operating Mode (OpMode) IDs distribution used in emission estimation. A simulated work zone with completed traffic operation was selected as a test bed. Sixty subjects were recruited for the tests, whose demographic distribution was based on the Census data in Houston, Texas. A scene of a pedestrian's crossing in the work zone was designed for the driving test. Meanwhile, a wireless communication system called Drivers Smart Advisory System (DSAS) was proposed and introduced in the driving simulation, which provided drivers with warning messages in the work zone. Two scenarios were designed for a leading vehicle as well as for a following vehicle driving through the work zone, which included a base test without any wireless communication systems, and a driving test with the trigger of the DSAS. Subjects' driving behaviors in the simulation were recorded to evaluate safety and estimate the vehicle emission using the Environmental Protection Agency (EPA) released emission model MOVES. The correlation between drivers' driving behavior and the distribution of the OpMode ID during each scenario was investigated. Results show that the DSAS was able to induce drivers to accelerate smoothly, keep longer headway distance and stop earlier for a hazardous situation in the work zone, which driving behaviors result in statistically significant reduction in vehicle emissions for almost all studied air pollutants (p-values range from 4.10E-51 to 2.18E-03). The emission reduction was achieved by the switching the distribution of the OpMode IDs from higher emission zones to lower emission zones

Evaluation of the late merge work zone traffic control strategy.

DOT National Transportation Integrated Search

2004-01-01

Several alternative lane merge strategies have been proposed in recent years to process vehicles through work zone lane closures more safely and efficiently. Among these is the late merge. With the late merge, drivers are instructed to use all lanes ...

Improving work-zone delineation on limited access highways.

DOT National Transportation Integrated Search

1989-01-01

The purpose of this study was to investigate vehicle guidance through work zones by evaluating the effectiveness of two primary components of traffic control relative to delineation. First, a comparison of the steady-burn lights presently used on top...

Design of lane merges at rural freeway construction work zones.

DOT National Transportation Integrated Search

2012-10-01

Practices for the design and control of work zone traffic control configurations have evolved over time : to reflect safer and more efficient management practices. However, they are also recognized as areas : of frequent vehicle conflicts that can ca...

Improving the effectiveness of smart work zone technologies.

DOT National Transportation Integrated Search

2016-11-01

This project evaluates the effectiveness of sensor network systems for work zone traffic estimation. The comparative analysis is : performed on a work zone modeled in microsimulation and calibrated with field data from two Illinois work zones. Realis...

Maintenance of Traffic for Innovative Geometric Design Work Zones

DOT National Transportation Integrated Search

2015-12-01

Currently there are no guidelines within the Manual on Uniform Traffic Control Devices (MUTCD) on construction phasing and maintenance of traffic (MOT) for retrofit construction and maintenance projects involving innovative geometric designs. The res...

Research notes : helping businesses in work zones.

DOT National Transportation Integrated Search

2001-03-01

Many business owners fear that highway construction projects will significantly reduce traffic to their businesses. Customers complain about the difficulty in finding business driveways in work zones. Drivers are guided through most work zone using o...

Effectiveness of work zone intelligent transportation systems.

DOT National Transportation Integrated Search

2013-12-01

In the last decade, Intelligent Transportation Systems (ITS) have increasingly been deployed in work zones by state departments of transportation. Also known as smart work zone systems they improve traffic operations and safety by providing real-time...

23 CFR 630.1110 - Maintenance of temporary traffic control devices.

Code of Federal Regulations, 2013 CFR

2013-04-01

... of Transportation “Quality Standards for Work Zone Traffic Control Devices” is available online at... Unacceptable” is available online at http://www.dot.state.mn.us/trafficeng/otepubl/fieldmanual2007/FM-2007...

23 CFR 630.1110 - Maintenance of temporary traffic control devices.

Code of Federal Regulations, 2012 CFR

2012-04-01

... of Transportation “Quality Standards for Work Zone Traffic Control Devices” is available online at... Unacceptable” is available online at http://www.dot.state.mn.us/trafficeng/otepubl/fieldmanual2007/FM-2007...

23 CFR 630.1110 - Maintenance of temporary traffic control devices.

Code of Federal Regulations, 2011 CFR

2011-04-01

... of Transportation “Quality Standards for Work Zone Traffic Control Devices” is available online at... Unacceptable” is available online at http://www.dot.state.mn.us/trafficeng/otepubl/fieldmanual2007/FM-2007...

23 CFR 630.1110 - Maintenance of temporary traffic control devices.

Code of Federal Regulations, 2014 CFR

2014-04-01

... of Transportation “Quality Standards for Work Zone Traffic Control Devices” is available online at... Unacceptable” is available online at http://www.dot.state.mn.us/trafficeng/otepubl/fieldmanual2007/FM-2007...

Effects of work zone configurations and traffic density on performance variables and subjective workload.

PubMed

Shakouri, Mahmoud; Ikuma, Laura H; Aghazadeh, Fereydoun; Punniaraj, Karthy; Ishak, Sherif

2014-10-01

This paper investigates the effect of changing work zone configurations and traffic density on performance variables and subjective workload. Data regarding travel time, average speed, maximum percent braking force and location of lane changes were collected by using a full size driving simulator. The NASA-TLX was used to measure self-reported workload ratings during the driving task. Conventional lane merge (CLM) and joint lane merge (JLM) were modeled in a driving simulator, and thirty participants (seven female and 23 male), navigated through the two configurations with two levels of traffic density. The mean maximum braking forces was 34% lower in the JLM configuration, and drivers going through the JLM configuration remained in the closed lane longer. However, no significant differences in speed were found between the two merge configurations. The analysis of self-reported workload ratings show that participants reported 15.3% lower total workload when driving through the JLM. In conclusion, the implemented changes in the JLM make it a more favorable merge configuration in both high and low traffic densities in terms of optimizing traffic flow by increasing the time and distance cars use both lanes, and in terms of improving safety due to lower braking forces and lower reported workload. Copyright © 2014 Elsevier Ltd. All rights reserved.

Minimum work analysis on the critical taper accretionary wedges- insights from analogue modeling

NASA Astrophysics Data System (ADS)

Santimano, Tasca; Rosenau, Matthias; Oncken, Onno

2014-05-01

The Critical taper theory (CTT) is a fundamental concept for the understanding of mountain building processes. Based on force balance it predicts the preferred steady state geometry of an accretionary wedge system and its tectonic regime (extensive, compressive, stable). However, it does not specify which structures are formed and reactivated to reach the preferred state. The latter can be predicted by the minimum work concept. Here we test both concepts and their interplay by analysing two simple sand wedge models which differ only in the thickness of the basal detachment (a layer of glass beads). While the steady state critical taper is controlled by internal and basal friction coefficients and therefore the same in all experiments, different processes can minimise work by 1. reducing gravitational work e.g. by lowering the amount of uplift or volume uplifted, or 2. reducing frictional work e.g. by lowering the load or due to low friction coefficient along thrusts. Since a thick detachment allows entrainment of low friction material and therefore lowering of the friction along active thrusts, we speculate that the style of wedge growth will differ between the two models. We observe that the wedge with a thin basal detachment localizes strain at the toe of the wedge periodically and reactivate older faults to reach the critical topography. On the contrary, in the wedge with the thicker detachment layer, friction along thrusts is lowered due to the entrainment of low friction material from the detachment zone, subsequently increasing the lifetime of a thrust. Long thrust episodes are always followed by a fault of shorter lifetime, with the aim of reaching the critical taper. From the two experiments, we analyze the time-series evolution of the wedge to infer the work done by the two styles of deformation and predict the trend over time to differ but the maximum work to be similar Our observations show that the critical taper theory determines the geometry of the

Development of a guideline for work zone diversion rate and capacity reduction.

DOT National Transportation Integrated Search

2016-03-01

This study develops a comprehensive guideline to estimate the traffic diversion rates and capacity reduction for : work zones. The analysis of the traffic diversion patterns with data from past work zones in the metro freeway : network in Minnesota r...

Modeling merging behavior at lane drops.

DOT National Transportation Integrated Search

2015-02-01

In work-zone configurations where lane drops are present, merging of traffic at the taper presents an operational concern. In : addition, as flow through the work zone is reduced, the relative traffic safety of the work zone is also reduced. Improvin...

Evaluation of the ADAPTIR System for Work Zone Traffic Control

DOT National Transportation Integrated Search

1999-11-01

The ADAPTIR system (Automated Data Acquisition and Processing of Traffic Information in Real Time) uses variable message signs (VMS) equipped with radar units, along with a software program to interpret the data, to display appropriate warning and ad...

23 CFR 630.1006 - Work zone safety and mobility policy.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 23 Highways 1 2011-04-01 2011-04-01 false Work zone safety and mobility policy. 630.1006 Section 630.1006 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS PRECONSTRUCTION PROCEDURES Work Zone Safety and Mobility § 630.1006 Work zone safety and mobility...

23 CFR 630.1006 - Work zone safety and mobility policy.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 23 Highways 1 2014-04-01 2014-04-01 false Work zone safety and mobility policy. 630.1006 Section 630.1006 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS PRECONSTRUCTION PROCEDURES Work Zone Safety and Mobility § 630.1006 Work zone safety and mobility...

23 CFR 630.1006 - Work zone safety and mobility policy.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 23 Highways 1 2013-04-01 2013-04-01 false Work zone safety and mobility policy. 630.1006 Section 630.1006 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS PRECONSTRUCTION PROCEDURES Work Zone Safety and Mobility § 630.1006 Work zone safety and mobility...

23 CFR 630.1006 - Work zone safety and mobility policy.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 23 Highways 1 2012-04-01 2012-04-01 false Work zone safety and mobility policy. 630.1006 Section 630.1006 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS PRECONSTRUCTION PROCEDURES Work Zone Safety and Mobility § 630.1006 Work zone safety and mobility...

Uncertainty analysis of accident notification time and emergency medical service response time in work zone traffic accidents.

PubMed

Meng, Qiang; Weng, Jinxian

2013-01-01

Taking into account the uncertainty caused by exogenous factors, the accident notification time (ANT) and emergency medical service (EMS) response time were modeled as 2 random variables following the lognormal distribution. Their mean values and standard deviations were respectively formulated as the functions of environmental variables including crash time, road type, weekend, holiday, light condition, weather, and work zone type. Work zone traffic accident data from the Fatality Analysis Report System between 2002 and 2009 were utilized to determine the distributions of the ANT and the EMS arrival time in the United States. A mixed logistic regression model, taking into account the uncertainty associated with the ANT and the EMS response time, was developed to estimate the risk of death. The results showed that the uncertainty of the ANT was primarily influenced by crash time and road type, whereas the uncertainty of EMS response time is greatly affected by road type, weather, and light conditions. In addition, work zone accidents occurring during a holiday and in poor light conditions were found to be statistically associated with a longer mean ANT and longer EMS response time. The results also show that shortening the ANT was a more effective approach in reducing the risk of death than the EMS response time in work zones. To shorten the ANT and the EMS response time, work zone activities are suggested to be undertaken during non-holidays, during the daytime, and in good weather and light conditions.

Missouri work zone capacity : results of field data analysis.

DOT National Transportation Integrated Search

2011-06-01

This report presents the results of work zone field data analyzed on interstate highways in Missouri to : determine the mean breakdown and queue-discharge flow rates as measures of capacity. Several days of : traffic data collected at a work zone nea...

Missouri Work Zone Capacity : Results of Field Data Analysis

DOT National Transportation Integrated Search

2011-06-01

This report presents the results of work zone field data analyzed on interstate highways in Missouri to determine : the mean breakdown and queue-discharge flow rates as measures of capacity. Several days of traffic data : collected at a work zone nea...

Community structure in traffic zones based on travel demand

NASA Astrophysics Data System (ADS)

Sun, Li; Ling, Ximan; He, Kun; Tan, Qian

2016-09-01

Large structure in complex networks can be studied by dividing it into communities or modules. Urban traffic system is one of the most critical infrastructures. It can be abstracted into a complex network composed of tightly connected groups. Here, we analyze community structure in urban traffic zones based on the community detection method in network science. Spectral algorithm using the eigenvectors of matrices is employed. Our empirical results indicate that the traffic communities are variant with the travel demand distribution, since in the morning the majority of the passengers are traveling from home to work and in the evening they are traveling a contrary direction. Meanwhile, the origin-destination pairs with large number of trips play a significant role in urban traffic network's community division. The layout of traffic community in a city also depends on the residents' trajectories.

Synthesis of work-zone performance measures.

DOT National Transportation Integrated Search

2013-09-01

The main objective of this synthesis was to identify and summarize how agencies collect, analyze, and report different work-zone : traffic-performance measures, which include exposure, mobility, and safety measures. The researchers also examined comm...

Investigation of work zone crash casualty patterns using association rules.

PubMed

Weng, Jinxian; Zhu, Jia-Zheng; Yan, Xuedong; Liu, Zhiyuan

2016-07-01

Investigation of the casualty crash characteristics and contributory factors is one of the high-priority issues in traffic safety analysis. In this paper, we propose a method based on association rules to analyze the characteristics and contributory factors of work zone crash casualties. A case study is conducted using the Michigan M-94/I-94/I-94BL/I-94BR work zone crash data from 2004 to 2008. The obtained association rules are divided into two parts including rules with high-lift, and rules with high-support for the further analysis. The results show that almost all the high-lift rules contain either environmental or occupant characteristics. The majority of association rules are centered on specific characteristics, such as drinking driving, the highway with more than 4 lanes, speed-limit over 40mph and not use of traffic control devices. It should be pointed out that some stronger associated rules were found in the high-support part. With the network visualization, the association rule method can provide more understandable results for investigating the patterns of work zone crash casualties. Copyright © 2016 Elsevier Ltd. All rights reserved.

Work zone safety : physical and behavioral barriers in accident prevention.

DOT National Transportation Integrated Search

2014-05-01

This report discusses the usefulness of creating a work zone traffic safety culture as a methodology to improve the overall : safety of both work zone personnel and the traveling public in Missouri. As part of this research, the existing MoDOT : Work...

Evaluation of data from test application of optical speed bars to highway work zones

DOT National Transportation Integrated Search

2004-08-01

The proximity of traffic and workers in highway work zones demand that safety be a high priority. : The issue of traffic speeds in highway work zones has long been an issue receiving much attention. Over the : past three decades, many different measu...

Vehicle accidents in highway work zones.

DOT National Transportation Integrated Search

1981-01-01

The objective of this study was to determine the magnitude and characteristics of safety problems, in terms of reported accidents, that are associated with moving vehicular traffic around and through highway work zones. This was accomplished by exami...

Research notes : nighttime illumination of work zone flaggers.

DOT National Transportation Integrated Search

2006-05-01

As daytime traffic demands increase, nighttime construction and maintenance work is becoming more prevalent. The effective and efficient illumination of flaggers in these work zones is a significant concern . Insufficient light levels, disabling glar...

Work zone lane closure analysis model.

DOT National Transportation Integrated Search

2009-10-01

At the Alabama Department of Transportation (ALDOT), the tool used by traffic engineers to predict whether a queue will form at a freeway work zone is the Excel-based "Lane Rental Model" developed at the Oklahoma Department of Transportation (OkDOT) ...

Meeting the customer's needs for mobility and safety during construction and maintenance operations : model work zone traffic management program and self evaluation guide

DOT National Transportation Integrated Search

1998-09-01

This model program was developed by combining traffic management concepts reported in research studies and papers with the effective techniques currently being used by States to minimize motorist delays and enhance work zone safety. This model is pre...

Work zone safety : physical and behavioral barriers in accident prevention.

DOT National Transportation Integrated Search

2014-05-01

This report discusses the usefulness of creating a work zone traffic safety culture as a methodology to improve the overall : safety of both work zone personnel and the traveling public in Missouri. As part of this research, the existing MoDOT : w : ...

From crisis to development--analysis of air traffic control work processes.

PubMed

Teperi, Anna-Maria; Leppänen, Anneli

2011-03-01

In this study an intervention to improve work processes in air traffic control (ATC) is evaluated. The background was the Finnish air traffic controllers' strike of 1999. The old ways of thinking and acting did not support development of ATC prompting a need for a new kind of working culture in the organisation. Several actions were started. In one of these, ATC work processes were modelled by personnel and development plans concerning work were delivered to top management. Different actors (management, trade union, stakeholders) were interviewed before (n=16) and after the project (n=7). The intervention supported systematic co-operation between different actors in the organisation. However, a follow-up revealed that only a few participants had adopted the idea of continuous work development. Mastery of human factors is crucial in a high reliability work environment such as ATC. But how is the analytical and co-operative aspect kept alive in an organisation that is run by strict international regulation and has a strong technical competence, but is not that strong in collaborative and human aspects? Copyright © 2010 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Integrated risk management for improving internal traffic control, work-zone safety, and mobility during major construction.

DOT National Transportation Integrated Search

2012-10-01

Highway construction is among the most dangerous industries in the US. Internal traffic control design, along with how construction : equipment and vehicles interact with the traveling public, have a significant effect on how safe a highway construct...

Evaluation of mobile work zone alarm systems.

DOT National Transportation Integrated Search

2014-06-01

Maintenance of highways often involves mobile work zones for various types of low speed moving operations such as : striping and sweeping. The speed differential between the moving operation and traffic, and the increasing problem of : distracted dri...

Satellite-aided coastal zone monitoring and vessel traffic system

NASA Technical Reports Server (NTRS)

Baker, J. L.

1981-01-01

The development and demonstration of a coastal zone monitoring and vessel traffic system is described. This technique uses a LORAN-C navigational system and relays signals via the ATS-3 satellite to a computer driven color video display for real time control. Multi-use applications of the system to search and rescue operations, coastal zone management and marine safety are described. It is emphasized that among the advantages of the system are: its unlimited range; compatibility with existing navigation systems; and relatively inexpensive cost.

Addressing work zone traffic safety issues in Arizona.

DOT National Transportation Integrated Search

2017-03-01

The occurrence of work zone crashes is expected to increase in Arizona with the Arizona Department of Transportations (ADOTs) shifted emphasis from constructing new roadways to preserving existing facilities. Identifying factors that contribute...

Identification of traffic control devices for mobile and short duration work operations

DOT National Transportation Integrated Search

2006-07-01

This report documents and summarizes the study Identification of Traffic Control Devices for Mobile and Short Duration Work Operations, for the New Jersey Department of Transportation. The study was conducted in three tasks: 1. Literature Searc...

Optimal design of work zone median crossovers.

DOT National Transportation Integrated Search

2010-09-01

The use of temporary median crossovers in work zones allows for the closure of one side of a multi-lane roadway while : maintaining two-way traffic on the opposite side. This process provides the ability for construction and maintenance crews : to co...

Minimizing traffic-related work zone crashes in Illinois.

DOT National Transportation Integrated Search

2013-04-01

This report presents the findings of a research project to study and develop recommendations to minimize work : zone crashes in Illinois. The objectives of this project were (1) to provide in-depth comprehensive review of the : latest literature on t...

Work-zone traffic performance measures : tech transfer summary.

DOT National Transportation Integrated Search

2013-09-01

The Federal Highway Administration (FHWA) 2004 Work Zone Safety and Mobility Rule applies to all state and local government agencies that receive federal-aid highway funding after October 12, 2007. This rule was an update to the former regulation (23...

Estimation of traffic impacts at work zones : state of the practice.

DOT National Transportation Integrated Search

2006-01-01

Assessing the safety and mobility impacts of work zones across the project development phases of road construction and maintenance projects is an emphasis area of the Federal Highway Administration's Final Rule on Work Zone Safety and Mobility1 (Fina...

Development of recommendations for arterial lane closures to optimize traffic operations.

DOT National Transportation Integrated Search

2013-01-01

The 2010 FDOT Design Standards provide information regarding traffic control through work zones at multilane arterials. : However, there are currently no quantitative guidelines for optimizing signal control around work zones. The objective of this :...

Proposed positive protection guidance for Kansas : synthesis of work zone positive protection devices and state of practice.

DOT National Transportation Integrated Search

2013-02-01

The United States experiences over 700 fatalities and over 37,000 injuries each year in temporary : construction and maintenance work zones. The Federal Highway Administration (FHWA) has implemented : Temporary Traffic Control Devices 23 CFR 630 Subp...

Catalog of Window Taper Functions for Sidelobe Control

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

Doerry, Armin W.

Window taper functions of finite apertures are well-known to control undesirable sidelobes, albeit with performance trades. A plethora of various taper functions have been developed over the years to achieve various optimizations. We herein catalog a number of window functions, and com pare principal characteristics.

Vehicle accidents at maintenance and utility work zones.

DOT National Transportation Integrated Search

1978-01-01

The objective of this study was to determine the magnitude and characteristics of safety problems, in terms of reported accidents, that are associated with moving vehicular traffic around and through highway maintenance and utility work zones. This w...

Capacity and road user cost analysis of selected freeway work zones in Texas.

DOT National Transportation Integrated Search

2009-09-01

This research was developed to produce usable and meaningful estimates for work zone capacities under a variety of roadway and traffic conditions, work zone configurations, and lane closure scenarios within Texas. Using data collected at eighteen wor...

Improving safety in high-speed work zones : a Super 70 study : [summary].

DOT National Transportation Integrated Search

2011-08-01

Highway work zones, particularly those on urban high-speed roads, require special attention and adequate traffic management to reduce the adverse impact of altered geometry and traffic that differ from typical conditions. Super 70 was an urban recons...

Evaluation of a mobile work zone barrier system.

DOT National Transportation Integrated Search

2013-08-01

A high percentage of highway maintenance activities and some construction activities are performed in a travel lane, median, or shoulder while the public travels by at relatively high speeds in very close proximity to the workers. Work zone traffic c...

Proposed positive protection guidance for Kansas : synthesis of work zone positive protection devices and state practice : [technical summary].

DOT National Transportation Integrated Search

2013-02-01

The United States experiences over 700 fatalities and over 37,000 injuries each year in : temporary construction and maintenance work zones. The Federal Highway Administration : (FHWA) has implemented Temporary Traffic Control Devices 23 CFR 630 Subp...

Crashworthiness testing of a portable maintenance work-zone barrier.

DOT National Transportation Integrated Search

2008-12-01

Barrier and shadow vehicles generally provide Caltrans maintenance workers protection from errant vehicles entering the work zones, from the upstream direction of traffic flow. This type of protection does not protect workers from vehicles entering t...

Comparison of debris extruded apically and working time used by ProTaper Universal rotary and ProTaper retreatment system during gutta-percha removal

PubMed Central

UEZU, Mary Kinue Nakamune; BRITTO, Maria Leticia Borges; NABESHIMA, Cleber K.; PALLOTTA, Raul Capp

2010-01-01

Objective The aim of this study was to evaluate the in vitro action of ProTaper retreatment files and ProTaper Universal in the retreatment of mandibular premolars. Material and methods The amount of debris extruded apically was measured and the time to reach the working length and to complete the removal of gutta-percha was observed. Thirty teeth had their canals prepared using ProTaper Universal files and were obturated by the single cone technique. The teeth were then stored at 37ºC in a humid environment for 7 days. During the use of the rotary instruments for root canal filling removal, the apical portions of the teeth were attached to the open end of a resin tube to collect the apically extruded debris. Results ProTaper Universal files were significantly faster (p=0.0011) than the ProTaper retreatment files to perform gutta-percha removal, but no significant difference was found between the files regarding the time to reach the working length or the amount of apical extrusion. Conclusions ProTaper Universal rotary had better results for endodontic retreatment, and both techniques promote similar apical extrusion of debris. PMID:21308282

Traffic incident management in construction and maintenance work zones.

DOT National Transportation Integrated Search

2009-01-01

In 2004, the Federal Highway Administration published updated rules governing work zone safety and mobility; all highway construction and maintenance projects using federal-aid highway funds are required to develop transportation management plans (TM...

Analysis of the frequency and severity of rear-end crashes in work zones.

PubMed

Qi, Yi; Srinivasan, Raghavan; Teng, Hualiang; Baker, Robert

2013-01-01

The objective of this study was to identify the factors that influence the frequency and severity of rear-end crashes in work zones because rear-end crashes represent a significant proportion of crashes that occur in work zones. Truncated count data models were developed to identify influencing factors on the frequency of read-end crashes in work zones and ordered probit models were developed to evaluate influencing factors on the severity of rear-end crashes in work zones. Most of the variables identified in this study for these 2 models were significant at the 95 percent level. The statistics for models indicate that the 2 developed models are appropriate compared to alternative models. Major findings related to the frequency of rear-end crashes include the following: (1) work zones for capacity and pavement improvements have the highest frequency compared to other types of work zones; (2) work zones controlled by flaggers are associated with more rear-end crashes compared to those controlled by arrow boards; and (3) work zones with alternating one-way traffic tended to have more rear-end crashes compared to those with lane shifts. Major findings related to the severity of the rear-end crashes include the following: (1) rear-end crashes associated with alcohol, night, pedestrians, and roadway defects are more severe, and those associated with careless backing, stalled vehicles, slippery roadways, and misunderstanding flagging signals are less severe; (2) truck involvement and a large number of vehicles in a crash are both associated with increased severity, and (3) rear-end crashes that happened in work zones for bridge, capacity, and pavement are likely to be more severe than others.

Public opinion and understanding of advance warning arrow displays used in short-term, mobile, and moving work zones.

DOT National Transportation Integrated Search

2008-03-01

"In long-term work zones on multilane highways and/or freeways, the Federal Highway Administration has interpreted the : Manual on Uniform Traffic Control Devices to mean that only one advance warning arrow displays can be used to denote : the closur...

Sleep patterns in air traffic controllers working rapidly rotating shifts : a field study.

DOT National Transportation Integrated Search

1995-04-01

This study was part of a research program in shift work and fatigue in the Air Traffic Control (ATC) environment. The purpose of the study was to investigate three different shift schedules in use at ATC facilities with respect to potential disruptio...

Calibration of work zone impact analysis software for Missouri.

DOT National Transportation Integrated Search

2013-12-01

This project calibrated two software programs used for estimating the traffic impacts of work zones. The WZ Spreadsheet : and VISSIM programs were recommended in a previous study by the authors. The two programs were calibrated using : field data fro...

Evaluation of a mobile work zone barrier system : appendices.

DOT National Transportation Integrated Search

2013-08-01

A high percentage of highway maintenance activities and some construction activities are performed in a travel lane, median, or shoulder while the public travels by at relatively high speeds in very close proximity to the workers. Work zone traffic c...

Implementing speed reductions at specific interstate work zones from 65 mph to 35 mph : final report.

DOT National Transportation Integrated Search

2013-02-01

Interstate preservation projects are commonly conducted at night and often require working in close proximity to ongoing traffic. Vehicle speed and speed variability in work zones is inextricably connected to the work zone design and the selected tra...

Cockpit displayed traffic information and distributed management in air traffic control

NASA Technical Reports Server (NTRS)

Kreifeldt, J. G.

1980-01-01

A graphical display of information (such as surrounding aircraft and navigation routes) in the cockpit on a cathode ray tube has been proposed for improving the safety, orderliness, and expeditiousness of the air traffic control system. An investigation of this method at NASA-Ames indicated a large reduction in controller verbal work load without increasing pilot verbal load; the visual work may be increased. The cockpit displayed traffic and navigation information system reduced response delays permitting pilots to maintain their spacing more closely and precisely than when depending entirely on controller-issued radar vectors and speed command.

Effects of an alternating work shift on air traffic controllers and the relationship with excessive daytime sleepiness and stress.

PubMed

Freitas, Ângela M; Portuguez, Mirna Wetters; Russomano, Thaís; Freitas, Marcos de; Silvello, Silvio Luis da Silva; Costa, Jaderson Costa da

2017-10-01

To evaluate symptoms of stress and excessive daytime sleepiness (EDS) in air traffic control (ATC) officers in Brazil. Fifty-two ATC officers participated, based at three air traffic control units, identified as A, B and C. Stress symptoms were assessed using the Lipp Inventory of Stress Symptoms for Adults, and EDS by the Epworth Sleepiness Scale. The sample mean age was 37 years, 76.9% of whom were male. Excessive daytime sleepiness was identified in 25% of the ATC officers, with 84.6% of these based at air traffic control unit A, which has greater air traffic flow, operating a 24-hour alternating work shift schedule. A total of 16% of the ATC officers had stress symptoms, and of these, 62% showed a predominance of physical symptoms. The high percentage of ATC officers with EDS identified in group A may be related to chronodisruption due to night work and alternating shifts.

Biological rhythms and rotating shift work : some considerations for air traffic controllers and managers.

DOT National Transportation Integrated Search

1986-01-01

This report is a general review of some of the current themes and practices regarding rotating shift work; to inform air traffic controllers, technicians, and managers of these issues; and to offer some ideas that may be helpful in dealing with diffi...

Comparison of modeled traffic exposure zones using on-road air pollution measurements

EPA Science Inventory

Modeled traffic data were used to develop traffic exposure zones (TEZs) such as traffic delay, high volume, and transit routes in the Research Triangle area of North Carolina (USA). On-road air pollution measurements of nitrogen dioxide (NO2), carbon monoxide (CO), carbon dioxid...

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...

Job attitudes of air traffic controllers : a comparison of three air traffic control specialties.

DOT National Transportation Integrated Search

1973-01-01

792 JOURNEYMAN AIR TRAFFIC CONTROLLERS FROM ARTCC, TRACON, and FSS facilities answered a four-part questionnaire concerning : 1.what they liked and disliked about ATC work, : 2.how much they liked or disliked certain specific aspects of ATC work, : 3...

Situational Leadership in Air Traffic Control

NASA Technical Reports Server (NTRS)

Arvidsson, Marcus; Johansson, Curt R.; Ek, Asa; Akselsson, Roland

2007-01-01

In high-risk environments such as air traffic control, leadership on different levels plays a certain role in establishing, promoting, and maintaining a good safety culture. The current study aimed to investigate how leadership styles, leadership style adaptability, and over and under task leadership behavior differed across situations, operative conditions, leadership structures, and working tasks in an air traffic control setting. Study locations were two air traffic control centers in Sweden with different operational conditions and leadership structures, and an administrative air traffic management unit. Leadership was measured with a questionnaire based on Leader Effectiveness and Adaptability Description (LEAD; Blanchard, Zigarmi & Zigarmi, 2003; Hersey & Blanchard, 1988). The results showed that the situation had strong impact on the leadership in which the leadership behavior was more relationship oriented in Success and Group situations than in Hardship and Individual situations. The leadership adaptability was further superior in Success and Individual situations compared with Hardship and Group situations. Operational conditions, leadership structures and working tasks were, on the other hand, not associated with leadership behavior.

Work zone safety analysis and modeling: a state-of-the-art review.

PubMed

Yang, Hong; Ozbay, Kaan; Ozturk, Ozgur; Xie, Kun

2015-01-01

crashes and other factors such as time, weather, victim severity, traffic control devices, and facility types. Moreover, both work zone crash frequency and severity models still rely on relatively simple modeling techniques and approaches. In addition, work zone data limitations have caused a number of challenges in analyzing and modeling work zone safety. Additional efforts on data collection, developing a systematic data analysis framework, and using more advanced modeling approaches are suggested as future research tasks.

Building the Brain's "Air Traffic Control" System: How Early Experiences Shape the Development of Executive Function. Working Paper 11

ERIC Educational Resources Information Center

National Scientific Council on the Developing Child, 2011

2011-01-01

Being able to focus, hold, and work with information in mind, filter distractions, and switch gears is like having an air traffic control system at a busy airport to manage the arrivals and departures of dozens of planes on multiple runways. In the brain, this air traffic control mechanism is called executive functioning, a group of skills that…

23 CFR 630.1108 - Work zone safety management measures and strategies.

Code of Federal Regulations, 2013 CFR

2013-04-01

... workers and road users, such as: (1) Work zones that provide workers no means of escape from motorized... exposure to motorized traffic and exposure of road users to work activities, while also providing adequate... individual projects, such as: (1) Full road closures; (2) Ramp closures; (3) Median crossovers; (4) Full or...

23 CFR 630.1108 - Work zone safety management measures and strategies.

Code of Federal Regulations, 2012 CFR

2012-04-01

... workers and road users, such as: (1) Work zones that provide workers no means of escape from motorized... exposure to motorized traffic and exposure of road users to work activities, while also providing adequate... individual projects, such as: (1) Full road closures; (2) Ramp closures; (3) Median crossovers; (4) Full or...

23 CFR 630.1108 - Work zone safety management measures and strategies.

Code of Federal Regulations, 2011 CFR

2011-04-01

... workers and road users, such as: (1) Work zones that provide workers no means of escape from motorized... exposure to motorized traffic and exposure of road users to work activities, while also providing adequate... individual projects, such as: (1) Full road closures; (2) Ramp closures; (3) Median crossovers; (4) Full or...

23 CFR 630.1108 - Work zone safety management measures and strategies.

Code of Federal Regulations, 2014 CFR

2014-04-01

... workers and road users, such as: (1) Work zones that provide workers no means of escape from motorized... exposure to motorized traffic and exposure of road users to work activities, while also providing adequate... individual projects, such as: (1) Full road closures; (2) Ramp closures; (3) Median crossovers; (4) Full or...

Implementing speed reductions at specific interstate work zones from 65 mph to 35 mph : appendices to final report.

DOT National Transportation Integrated Search

2013-02-01

Interstate preservation projects are commonly conducted at night and often require working in close proximity to ongoing traffic. Vehicle speed and speed variability in work zones is inextricably connected to the work zone design and the selected tra...

Automatic speech recognition in air traffic control

NASA Technical Reports Server (NTRS)

Karlsson, Joakim

1990-01-01

Automatic Speech Recognition (ASR) technology and its application to the Air Traffic Control system are described. The advantages of applying ASR to Air Traffic Control, as well as criteria for choosing a suitable ASR system are presented. Results from previous research and directions for future work at the Flight Transportation Laboratory are outlined.

Improved work zone design guidelines and enhanced model of travel delays in work zones : Phase I, portability and scalability of interarrival and service time probability distribution functions for different locations in Ohio and the establishment of impr

DOT National Transportation Integrated Search

2006-01-01

Problem: Work zones on heavily traveled divided highways present problems to motorists in the form of traffic delays and increased accident risks due to sometimes reduced motorist guidance, dense traffic, and other driving difficulties. To minimize t...

How to reduce workload--augmented reality to ease the work of air traffic controllers.

PubMed

Hofmann, Thomas; König, Christina; Bruder, Ralph; Bergner, Jörg

2012-01-01

In the future the air traffic will rise--the workload of the controllers will do the same. In the BMWi research project, one of the tasks is, how to ensure safe air traffic, and a reasonable workload for the air traffic controllers. In this project it was the goal to find ways how to reduce the workload (and stress) for the controllers to allow safe air traffic, esp. at huge hub-airports by implementing augmented reality visualization and interaction.

Applicability of Zipper Merge Versus Early Merge in Kentucky Work Zones

DOT National Transportation Integrated Search

2017-12-24

In an effort to improve work zone safety and streamline traffic flows, a number of state transportation agencies (STAs) have experimented with the zipper merge. The zipper merge differs from a conventional, or early, merge in that vehicles do not mer...

Holiday Perspectives on Air Traffic Control

NASA Image and Video Library

2016-12-14

As America travels over the holidays, NASA’s FutureFlight Central (FFC) is working to help passengers get to their destinations on time. The 360-degree virtual air traffic control tower is capable of simulating traffic and weather conditions to include snow, sleet and rain at almost any airport in the United States.

Integrated risk management for improving internal traffic control, work-zone safety, and mobility during major construction : tech transfer summary.

DOT National Transportation Integrated Search

2012-10-01

Construction work zones are among the most dangerous places to work in any industry in the world. This is because many factors in construction, such as constant change in working environments and driver errors, contribute to a workplace with a higher...

Studies to determine the effectiveness of longitudinal channelizing devices in work zones.

DOT National Transportation Integrated Search

2011-01-01

This report describes the methodology and results of analyses performed to determine whether the following longitudinal : channelizing device (LCD) applications improve the traffic safety and operations of work zones relative to the use of standard :...

Minimizing user delay and crash potential through highway work zone planning.

DOT National Transportation Integrated Search

2014-05-01

Lane closures due to highway work zones introduce many challenges to ensuring smooth traffic operations and a : safe environment for drivers and workers. In addition, merging has been found to be one of the most stressful : aspects of driving and a m...

Safety evaluation of joint and conventional lane merge configurations for freeway work zones.

PubMed

Ishak, Sherif; Qi, Yan; Rayaprolu, Pradeep

2012-01-01

Inefficient operation of traffic in work zone areas not only leads to an increase in travel time delays, queue length, and fuel consumption but also increases the number of forced merges and roadway accidents. This study evaluated the safety performance of work zones with a conventional lane merge (CLM) configuration in Louisiana. Analysis of variance (ANOVA) was used to compare the crash rates for accidents involving fatalities, injuries, and property damage only (PDO) in each of the following 4 areas: (1) advance warning area, (2) transition area, (3) work area, and (4) termination area. The analysis showed that the advance warning area had higher fatality, injury, and PDO crash rates when compared to the transition area, work area, and termination area. This finding confirmed the need to make improvements in the advance warning area where merging maneuvers take place. Therefore, a new lane merge configuration, called joint lane merge (JLM), was proposed and its safety performance was examined and compared to the conventional lane merge configuration using a microscopic simulation model (VISSIM), which was calibrated with real-world data from an existing work zone on I-55 and used to simulate a total of 25 different scenarios with different levels of demand and traffic composition. Safety performance was evaluated using 2 surrogate measures: uncomfortable decelerations and speed variance. Statistical analysis was conducted to determine whether the differences in safety performance between both configurations were significant. The safety analysis indicated that JLM outperformed CLM in most cases with low to moderate flow rates and that the percentage of trucks did not have a significant impact on the safety performance of either configuration. Though the safety analysis did not clearly indicate which lane merge configuration is safer for the overall work zone area, it was able to identify the possibly associated safety changes within the work zone area under

Task Analysis Assessment on Intrastate Bus Traffic Controllers

NASA Astrophysics Data System (ADS)

Yen Bin, Teo; Azlis-Sani, Jalil; Nur Annuar Mohd Yunos, Muhammad; Ismail, S. M. Sabri S. M.; Tajedi, Noor Aqilah Ahmad

2016-11-01

Public transportation acts as social mobility and caters the daily needs of the society for passengers to travel from one place to another. This is true for a country like Malaysia where international trade has been growing significantly over the past few decades. Task analysis assessment was conducted with the consideration of cognitive ergonomic view towards problem related to human factors. Conducting research regarding the task analysis on bus traffic controllers had allowed a better understanding regarding the nature of work and the overall monitoring activities of the bus services. This paper served to study the task analysis assessment on intrastate bus traffic controllers and the objectives of this study include to conduct task analysis assessment on the bus traffic controllers. Task analysis assessment for the bus traffic controllers was developed via Hierarchical Task Analysis (HTA). There are a total of five subsidiary tasks on level one and only two were able to be further broken down in level two. Development of HTA allowed a better understanding regarding the work and this could further ease the evaluation of the tasks conducted by the bus traffic controllers. Thus, human error could be reduced for the safety of all passengers and increase the overall efficiency of the system. Besides, it could assist in improving the operation of the bus traffic controllers by modelling or synthesizing the existing tasks if necessary.

Sleep in air traffic controllers.

DOT National Transportation Integrated Search

1977-02-01

Data obtained from sleep logs maintained for a period of 5 weeks by 185 air traffic controllers indicate that on a weekly basis there is no significant difference in the amount of sleep obtained by controllers working the 2-2-1 rotation pattern and t...

CATS-based Air Traffic Controller Agents

NASA Technical Reports Server (NTRS)

Callantine, Todd J.

2002-01-01

-in-the-loop simulations are unquestionably valuable for this purpose, but pose considerable logistical, fiscal, and experimental control problems. First, data analysis is extremely complicated, owing simply to the large number of participants and data sources in such simulations. In addition, experienced human air traffic controllers working adjacent sectors tend to flexibly adapt to the evolving control problem - potentially shifting to other strategies than those under investigation. In addition, their performance is tightly coupled to the control interface, which in the development phase may support some concepts and supporting strategies better than others. A simple shift in strategy by one controller can change the character of a particular traffic scenario dramatically, which makes experimental comparison of ATC performance under different traffic scenarios difficult. Training a given team of controllers on operations under a new ATM concept for a sufficient period of time could avert such difficulties, but instituting an adequate training program is expensive and logistically difficult.

An intelligent decision support system for work zone traffic management and planning.

DOT National Transportation Integrated Search

2004-01-01

Periodic resurfacing, rehabilitation, restoration, and reconstruction work is needed on the aging highway system in the state of Ohio to maintain a desired level of service for the traveling public. However, temporary work zones on highways disrupt t...

Hand-operated and rotary ProTaper instruments: a comparison of working time and number of rotations in simulated root canals.

PubMed

Pasqualini, Damiano; Scotti, Nicola; Tamagnone, Lorenzo; Ellena, Federica; Berutti, Elio

2008-03-01

The aim of this study was to compare the effective shaping time and number of rotations required by an endodontist working with hand and rotary ProTaper instruments to completely shape simulated root canals. Eighty Endo Training Blocks (curved canal shape) were used. Manual preflaring was performed with K-Flexofiles #08-10-12-15-17 and #20 Nitiflex at a working length of 18 mm. Specimens were then randomly assigned to 2 different groups (n = 40); group 1 was shaped by using hand ProTaper and group 2 with ProTaper rotary. The number of rotations made in the canal and the effective time required to achieve complete canal shaping were recorded for each instrument. Differences between groups were analyzed with the nonparametric Mann-Whitney U test (P < .05). Hand ProTaper required significantly fewer rotations (P < .001) than rotary ProTaper, whereas the effective working time to fully shape the simulated canal was significantly higher (P < .001) with hand ProTaper.

The employment of a spoken language computer applied to an air traffic control task.

NASA Technical Reports Server (NTRS)

Laveson, J. I.; Silver, C. A.

1972-01-01

Assessment of the merits of a limited spoken language (56 words) computer in a simulated air traffic control (ATC) task. An airport zone approximately 60 miles in diameter with a traffic flow simulation ranging from single-engine to commercial jet aircraft provided the workload for the controllers. This research determined that, under the circumstances of the experiments carried out, the use of a spoken-language computer would not improve the controller performance.

Human factors aspects of air traffic control

NASA Technical Reports Server (NTRS)

Older, H. J.; Cameron, B. J.

1972-01-01

An overview of human factors problems associated with the operation of present and future air traffic control systems is presented. A description is included of those activities and tasks performed by air traffic controllers at each operational position within the present system. Judgemental data obtained from controllers concerning psychological dimensions related to these tasks and activities are also presented. The analysis includes consideration of psychophysiological dimensions of human performance. The role of the human controller in present air traffic control systems and his predicted role in future systems is described, particularly as that role changes as the result of the system's evolution towards a more automated configuration. Special attention is directed towards problems of staffing, training, and system operation. A series of ten specific research and development projects are recommended and suggested work plans for their implementation are included.

Preliminary Investigation of Workload on Intrastate Bus Traffic Controllers

NASA Astrophysics Data System (ADS)

Yen Bin, Teo; Azlis-Sani, Jalil; Nur Annuar Mohd Yunos, Muhammad; Ismail, S. M. Sabri S. M.; Tajedi, Noor Aqilah Ahmad

2016-11-01

The daily routine of bus traffic controller which involves high mental processes would have a direct impact on the level of workload. To date, the level of workload on the bus traffic controllers in Malaysia is relatively unknown. Excessive workload on bus traffic controllers would affect the control and efficiency of the system. This paper served to study the workload on bus traffic controllers and justify the needs to conduct further detailed research on this field. The objectives of this research are to identify the level of workload on the intrastate bus traffic controllers. Based on the results, recommendations will be proposed for improvements and future studies. The level of workload for the bus traffic controllers is quantified using questionnaire adapted from NASA TLX. Interview sessions were conducted for validation of workload. Sixteen respondents were involved and it was found that the average level of workload based on NASA TLX was 6.91. It was found that workload is not affected by gender and marital status. This study also showed that the level of workload and working experience of bus traffic controllers has a strong positive linear relationship. This study would serve as a guidance and reference related to this field. Since this study is a preliminary investigation, further detailed studies could be conducted to obtain a better comprehension regarding the bus traffic controllers.

Traffic analysis and control using image processing

NASA Astrophysics Data System (ADS)

Senthilkumar, K.; Ellappan, Vijayan; Arun, A. R.

2017-11-01

This paper shows the work on traffic analysis and control till date. It shows an approach to regulate traffic the use of image processing and MATLAB systems. This concept uses computational images that are to be compared with original images of the street taken in order to determine the traffic level percentage and set the timing for the traffic signal accordingly which are used to reduce the traffic stoppage on traffic lights. They concept proposes to solve real life scenarios in the streets, thus enriching the traffic lights by adding image receivers like HD cameras and image processors. The input is then imported into MATLAB to be used. as a method for calculating the traffic on roads. Their results would be computed in order to adjust the traffic light timings on a particular street, and also with respect to other similar proposals but with the added value of solving a real, big instance.

FAA Air Traffic Control Operations Concepts. Volume 7. ATCT (Airport Traffic Control Towers) Tower Controllers

DTIC Science & Technology

1989-04-21

kift rIn FAA AIR TRAFFIC CONTROL OPERATIONS CONCEPTS V olum e V iI:.................... ATCT Tower Controllers AmELECTE JUL 2 11989 21 April 1989 A...01 022.3013209-87-B 11 a FAA AIR TRAFFIC CONTROL OPERATIONS CONCEPTS VOLUME VII: ATCT TOWER CONTROLLERS CDRL Bl 12, VOL. VII CONTRACT DTF-AO1-85-Y...INCORPORATED 7150 Campus Drive, Suite 100 Colorado Springs, CO 80920 (719) 590-5100 DOT/FAA/AP-87-0i (VOL#7) 21 April 1989 FAA AIR TRAFFIC CONTROL OPERATIONS

An intelligent traffic controller

DOT National Transportation Integrated Search

1995-11-01

Advances in computing sciences have not been applied to traffic control. This paper describes the development of an intelligent controller. A controller with advanced control logic can significantly improve traffic flows at intersections. In this vei...

Cognitive process modelling of controllers in en route air traffic control.

PubMed

Inoue, Satoru; Furuta, Kazuo; Nakata, Keiichi; Kanno, Taro; Aoyama, Hisae; Brown, Mark

2012-01-01

In recent years, various efforts have been made in air traffic control (ATC) to maintain traffic safety and efficiency in the face of increasing air traffic demands. ATC is a complex process that depends to a large degree on human capabilities, and so understanding how controllers carry out their tasks is an important issue in the design and development of ATC systems. In particular, the human factor is considered to be a serious problem in ATC safety and has been identified as a causal factor in both major and minor incidents. There is, therefore, a need to analyse the mechanisms by which errors occur due to complex factors and to develop systems that can deal with these errors. From the cognitive process perspective, it is essential that system developers have an understanding of the more complex working processes that involve the cooperative work of multiple controllers. Distributed cognition is a methodological framework for analysing cognitive processes that span multiple actors mediated by technology. In this research, we attempt to analyse and model interactions that take place in en route ATC systems based on distributed cognition. We examine the functional problems in an ATC system from a human factors perspective, and conclude by identifying certain measures by which to address these problems. This research focuses on the analysis of air traffic controllers' tasks for en route ATC and modelling controllers' cognitive processes. This research focuses on an experimental study to gain a better understanding of controllers' cognitive processes in air traffic control. We conducted ethnographic observations and then analysed the data to develop a model of controllers' cognitive process. This analysis revealed that strategic routines are applicable to decision making.

WorkZoneQ user guide for two-lane freeway work zones.

DOT National Transportation Integrated Search

2013-06-01

WorkZoneQ was developed in Visual Basic for Applications (VBA) to implement the results of the previous study, : Queue and Users Costs in Highway Work Zones. This report contains the WorkZoneQ user guide. WorkZoneQ : consists of eight Excel ...

Effects of road construction intensity and operations on rural freeway work zone capacity.

DOT National Transportation Integrated Search

2014-11-01

Capacity is affected by construction type and its intensity on adjacent open traffic lanes. The effect on capacity is a function of : vehicles moving in and out of the closed lanes of the work zone, and the presence of heavy construction vehicles. Co...

Consensus-Based Cooperative Control Based on Pollution Sensing and Traffic Information for Urban Traffic Networks

PubMed Central

Artuñedo, Antonio; del Toro, Raúl M.; Haber, Rodolfo E.

2017-01-01

Nowadays many studies are being conducted to develop solutions for improving the performance of urban traffic networks. One of the main challenges is the necessary cooperation among different entities such as vehicles or infrastructure systems and how to exploit the information available through networks of sensors deployed as infrastructures for smart cities. In this work an algorithm for cooperative control of urban subsystems is proposed to provide a solution for mobility problems in cities. The interconnected traffic lights controller (TLC) network adapts traffic lights cycles, based on traffic and air pollution sensory information, in order to improve the performance of urban traffic networks. The presence of air pollution in cities is not only caused by road traffic but there are other pollution sources that contribute to increase or decrease the pollution level. Due to the distributed and heterogeneous nature of the different components involved, a system of systems engineering approach is applied to design a consensus-based control algorithm. The designed control strategy contains a consensus-based component that uses the information shared in the network for reaching a consensus in the state of TLC network components. Discrete event systems specification is applied for modelling and simulation. The proposed solution is assessed by simulation studies with very promising results to deal with simultaneous responses to both pollution levels and traffic flows in urban traffic networks. PMID:28445398

Consensus-Based Cooperative Control Based on Pollution Sensing and Traffic Information for Urban Traffic Networks.

PubMed

Artuñedo, Antonio; Del Toro, Raúl M; Haber, Rodolfo E

2017-04-26

Nowadays many studies are being conducted to develop solutions for improving the performance of urban traffic networks. One of the main challenges is the necessary cooperation among different entities such as vehicles or infrastructure systems and how to exploit the information available through networks of sensors deployed as infrastructures for smart cities. In this work an algorithm for cooperative control of urban subsystems is proposed to provide a solution for mobility problems in cities. The interconnected traffic lights controller ( TLC ) network adapts traffic lights cycles, based on traffic and air pollution sensory information, in order to improve the performance of urban traffic networks. The presence of air pollution in cities is not only caused by road traffic but there are other pollution sources that contribute to increase or decrease the pollution level. Due to the distributed and heterogeneous nature of the different components involved, a system of systems engineering approach is applied to design a consensus-based control algorithm. The designed control strategy contains a consensus-based component that uses the information shared in the network for reaching a consensus in the state of TLC network components. Discrete event systems specification is applied for modelling and simulation. The proposed solution is assessed by simulation studies with very promising results to deal with simultaneous responses to both pollution levels and traffic flows in urban traffic networks.

Utilization of remote traffic monitoring devices for urban freeway work zone assessment.

DOT National Transportation Integrated Search

2012-01-01

The objective of this project was to promote and facilitate analysis and evaluation of the impacts of road construction activities in Smart : Work Zone Deployment Initiative (SWZDI) states. : The two primary objectives of this project were to assess ...

Ophthalmic requirements and considerations for the en route air traffic control specialist : an ergonomic analysis of the visual work environment.

DOT National Transportation Integrated Search

1996-04-01

The Federal Air Surgeon requested continued investigation of visual disorders and vision corrective devices as to their relevance to the medical certification of airmen and controllers. The en route Air Traffic Control Specialist (ATCS) works with a ...

Toward the development of a new selection battery for air traffic control specialists.

DOT National Transportation Integrated Search

1979-09-01

In an effort to update and refine the selection battery for air traffic controllers, five experimental tests measuring aptitudes and skills considered important in air traffic work were administered to newly selected Air Traffic Control Specialist (A...

Effectiveness of changeable message signs in controlling vehicle speeds in work zones.

DOT National Transportation Integrated Search

1994-01-01

Work zone speeds have customarily been regulated by standard regulatory or advisory speed signs. However, most drivers do not slow down in response to these static speed control measures. The changeable message sign (CMS) with radar unit has dynamic ...

Intelligent Traffic Light Based on PLC Control

NASA Astrophysics Data System (ADS)

Mei, Lin; Zhang, Lijian; Wang, Lingling

2017-11-01

The traditional traffic light system with a fixed control mode and single control function is contradicted with the current traffic section. The traditional one has been unable to meet the functional requirements of the existing flexible traffic control system. This paper research and develop an intelligent traffic light called PLC control system. It uses PLC as control core, using a sensor module for receiving real-time information of vehicles, traffic control mode for information to select the traffic lights. Of which control mode is flexible and changeable, and it also set the countdown reminder to improve the effectiveness of traffic lights, which can realize the goal of intelligent traffic diversion, intelligent traffic diversion.

Evaluation of chevron patterns for use on traffic control devices in street and highway work zones.

DOT National Transportation Integrated Search

1980-01-01

The chevron pattern consists of alternate orange and white stripes that form an arrow pointing in the direction in which traffic is being diverted. The objectives of this research were (1) to select the most effective design for the chevron pattern, ...

Reducing work zone crashes by using vehicle's flashers as a warning sign : final report

DOT National Transportation Integrated Search

2009-01-01

Rural two-lane highways constitute a large percentage of the highway system in Kansas. Preserving, expending, : and enhancing these highways require the set-up of a large number of one-lane, two-way work zones where traffic : safety has been a severe...

Traffic control systems handbook.

DOT National Transportation Integrated Search

2005-10-01

The Traffic Control Systems Handbook updates the 1996 edition (FHWA-SA-96-032). It serves as a basic reference in planning, designing and implementing traffic control systems. : Specific chapters include introduction, summary of available and emergin...

Measurement of Temporal Awareness in Air Traffic Control

NASA Technical Reports Server (NTRS)

Rantanen, E.M.

2009-01-01

Temporal awareness, or level 3 situation awareness, is critical to successful control of air traffic, yet the construct remains ill-defined and difficult to measure. This research sought evidence for air traffic controllers awareness of temporal characteristics of their tasks in data from a high-fidelity system evaluation simulation. Five teams of controllers worked on four scenarios with different traffic load. Several temporal parameters were defined for each task controllers performed during a simulation run and their actions on the tasks were timed relative to them. Controllers showed a strong tendency to prioritize tasks according to a first come, first served principle. This trend persisted as task load increased. Also evident was awareness of the urgency of tasks, as tasks with impending closing of a window of opportunity were performed before tasks that had longer time available before closing of the window.

Investigation of accidents within construction zones in Louisiana.

DOT National Transportation Integrated Search

1981-07-01

This investigation is to analyze construction and maintenance work zone accidents by reviewing accident data to determine if deficiencies exist and recommend possible corrective measures for future traffic control applications. To accomplish this, a ...

Traffic control systems handbook

DOT National Transportation Integrated Search

2005-10-01

The 2005 edition of "Traffic Control Systems Handbook" updates the 1996 edition (FHWA-SA-96-032). It serves as a basic reference in planning, designing and implementing traffic control systems. Specific chapters include introduction, summary of avail...

Analysis of work zone rear-end crash risk for different vehicle-following patterns.

PubMed

Weng, Jinxian; Meng, Qiang; Yan, Xuedong

2014-11-01

This study evaluates rear-end crash risk associated with work zone operations for four different vehicle-following patterns: car-car, car-truck, truck-car and truck-truck. The deceleration rate to avoid the crash (DRAC) is adopted to measure work zone rear-end crash risk. Results show that the car-truck following pattern has the largest rear-end crash risk, followed by truck-truck, truck-car and car-car patterns. This implies that it is more likely for a car which is following a truck to be involved in a rear-end crash accident. The statistical test results further confirm that rear-end crash risk is statistically different between any two of the four patterns. We therefore develop a rear-end crash risk model for each vehicle-following pattern in order to examine the relationship between rear-end crash risk and its influencing factors, including lane position, the heavy vehicle percentage, lane traffic flow and work intensity which can be characterized by the number of lane reductions, the number of workers and the amount of equipment at the work zone site. The model results show that, for each pattern, there will be a greater rear-end crash risk in the following situations: (i) heavy work intensity; (ii) the lane adjacent to work zone; (iii) a higher proportion of heavy vehicles and (iv) greater traffic flow. However, the effects of these factors on rear-end crash risk are found to vary according to the vehicle-following patterns. Compared with the car-car pattern, lane position has less effect on rear-end crash risk in the car-truck pattern. The effect of work intensity on rear-end crash risk is also reduced in the truck-car pattern. Copyright © 2014 Elsevier Ltd. All rights reserved.

Developing a smartphone based warning system application to enhance the safety at work zones : final report.

DOT National Transportation Integrated Search

2016-05-01

Collisions in the work zone have always been a contributing factor to compromising safety on urban roadways. The National Highway Traffic Safety Administration (NHTSA) and the State Transportation Authorities have implemented many safety countermeasu...

Simulation of traffic control signal systems

NASA Technical Reports Server (NTRS)

Connolly, P. J.; Concannon, P. A.; Ricci, R. C.

1974-01-01

In recent years there has been considerable interest in the development and testing of control strategies for networks of urban traffic signal systems by simulation. Simulation is an inexpensive and timely method for evaluating the effect of these traffic control strategies since traffic phenomena are too complex to be defined by analytical models and since a controlled experiment may be hazardous, expensive, and slow in producing meaningful results. This paper describes the application of an urban traffic corridor program, to evaluate the effectiveness of different traffic control strategies for the Massachusetts Avenue TOPICS Project.

Planning in air traffic control

DOT National Transportation Integrated Search

2001-12-01

An experiment was conducted to examine the planning activities of en route air traffic controllers. : Controllers were placed in the role of planners and verbalized a plan for controlling traffic to a tactician : (another controller) who implemented ...

Guidelines for developing traffic incident management plans for work zones

DOT National Transportation Integrated Search

2003-09-01

The Colorado Department of Transportation (CDOT) has led the development of a number of traffic incident management plans and programs throughout the state. These programs address procedural and coordination aspects of managing unplanned events on th...

Traffic control device evaluation program : technical report.

DOT National Transportation Integrated Search

2015-03-01

This project provides the Texas Department of Transportation with a mechanism to quickly and effectively conduct : high-priority, limited scope evaluations of traffic control devices. Work during the 20132014 fiscal year included : three main task...

Simple taper: Taper equations for the field forester

Treesearch

David R. Larsen

2017-01-01

"Simple taper" is set of linear equations that are based on stem taper rates; the intent is to provide taper equation functionality to field foresters. The equation parameters are two taper rates based on differences in diameter outside bark at two points on a tree. The simple taper equations are statistically equivalent to more complex equations. The linear...

Some effects of 8- vs 10-hour work schedules on the test performance/alertness of air traffic control specialists.

DOT National Transportation Integrated Search

1995-12-01

A 10-hour, 4-day rotating shift schedule worked by some Air Traffic Control Specialists (ATCSs) was compared to the more traditional 8-hour, 2-2-1 rapidly rotating schedule. Measures of performance and alertness were obtained from a group of 52 ATCSs...

76 FR 54156 - National Standards for Traffic Control Devices; the Manual on Uniform Traffic Control Devices for...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-31

... traffic control device design, location, or operation that have made some existing devices in the field...-2010-0159] RIN 2125-AF43 National Standards for Traffic Control Devices; the Manual on Uniform Traffic Control Devices for Streets and Highways; Revision AGENCY: Federal Highway Administration (FHWA...

77 FR 28460 - National Standards for Traffic Control Devices; the Manual on Uniform Traffic Control Devices for...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-14

...-2010-0159] RIN 2125-AF43 National Standards for Traffic Control Devices; the Manual on Uniform Traffic Control Devices for Streets and Highways; Revision AGENCY: Federal Highway Administration (FHWA..., approved by the FHWA, and recognized as the national standard for traffic control devices used on all...

A Cooperative Traffic Control of Vehicle–Intersection (CTCVI) for the Reduction of Traffic Delays and Fuel Consumption

PubMed Central

Li, Jinjian; Dridi, Mahjoub; El-Moudni, Abdellah

2016-01-01

The problem of reducing traffic delays and decreasing fuel consumption simultaneously in a network of intersections without traffic lights is solved by a cooperative traffic control algorithm, where the cooperation is executed based on the connection of Vehicle-to-Infrastructure (V2I). This resolution of the problem contains two main steps. The first step concerns the itinerary of which intersections are chosen by vehicles to arrive at their destination from their starting point. Based on the principle of minimal travel distance, each vehicle chooses its itinerary dynamically based on the traffic loads in the adjacent intersections. The second step is related to the following proposed cooperative procedures to allow vehicles to pass through each intersection rapidly and economically: on one hand, according to the real-time information sent by vehicles via V2I in the edge of the communication zone, each intersection applies Dynamic Programming (DP) to cooperatively optimize the vehicle passing sequence with minimal traffic delays so that the vehicles may rapidly pass the intersection under the relevant safety constraints; on the other hand, after receiving this sequence, each vehicle finds the optimal speed profiles with the minimal fuel consumption by an exhaustive search. The simulation results reveal that the proposed algorithm can significantly reduce both travel delays and fuel consumption compared with other papers under different traffic volumes. PMID:27999333

Broadcast control of air traffic

NASA Technical Reports Server (NTRS)

Litchford, G. B.

1972-01-01

Applications of wide range broadcast procedures to improve air traffic control and make more airspace available are discussed. A combination of the Omega navigation system and the very high frequency omnirange (VOR) is recommended as a means for accomplishing improved air traffic control. The benefits to be derived by commercial and general aviation are described. The air/ground communications aspects of the improved air traffic control system are explained. Research and development programs for implementing the broadcast concept are recommended.

Pedestrian Friendly Traffic Signal Control.

DOT National Transportation Integrated Search

2016-01-01

This project continues research aimed at real-time detection and use of pedestrian : traffic flow information to enhance adaptive traffic signal control in urban areas : where pedestrian traffic is substantial and must be given appropriate attention ...

Hoarseness and vocal tract discomfort and associated risk factors in air traffic controllers.

PubMed

Korn, Gustavo Polacow; Villar, Anna Carolina; Azevedo, Renata Rangel

2018-04-05

An air traffic controller is a professional who performs air traffic control functions in air traffic control units and is responsible for controlling the various stages of a flight. To compare hoarseness and vocal tract discomfort and their risk factors among air traffic controllers in the approach control of São Paulo. In a cross-sectional survey, a voice self-evaluation adapted from to self-evaluation prepared by the Brazilian Ministry of Labor for teachers was administered to 76 air traffic controllers at approach control of São Paulo, Brazil. The percentage of hoarseness and vocal tract discomfort was 19.7% and 38.2%, respectively. In relation to air pollution, the percentages of hoarseness and vocal tract discomfort were higher among those who consider their working environment to be intolerable than among those in a comfortable or disturbing environment. The percentage of hoarseness was higher among those who seek medical advice due to vocal complaints and among those who experience difficulty using their voice at work than among those who experience mild or no difficulty. The percentage of vocal tract discomfort was higher among those in a very tense and stressful environment than among those who consider their work environment to be mild or moderately tense and stressful. The percentage of vocal tract discomfort was higher among those who describe themselves as very tense and stressed or tense and stressed than among those who describe themselves as calm. Additionally, the percentage of vocal tract discomfort was higher among those who care about their health. Among air traffic controllers, the percentage of vocal tract discomfort was almost twice that of hoarseness. Both symptoms are prevalent among air traffic controllers who considered their workplace intolerable in terms of air pollution. Vocal tract discomfort was related to a tense and stressful environment, and hoarseness was related to difficulty using the voice at work. Copyright © 2018 Associa

Tapering Practices of Strongman Athletes.

PubMed

Winwood, Paul W; Dudson, Mike K; Wilson, Daniel; Mclaren-Harrison, Justice K H; Redjkins, Vladislav; Pritchard, Hayden J; Keogh, Justin W L

2018-05-01

Winwood, PW, Dudson, MK, Wilson, D, Mclaren-Harrison, JKH, Redjkins, V, Pritchard, HJ, and Keogh, JWL. Tapering practices of strongman athletes. J Strength Cond Res 32(5): 1181-1196, 2018-This study provides the first empirical evidence of how strongman athletes taper for strongman competitions. Strongman athletes (n = 454) (mean ± SD: 33.2 ± 8.0 years, 178.1 ± 10.6 cm, 108.6 ± 27.9 kg, 12.6 ± 8.9 years general resistance training, 5.3 ± 5.0 years strongman implement training) completed a self-reported 4-page internet survey on tapering practices. Analysis by sex (male and female), age (≤30 and >30 years), body mass (≤105 and >105 kg), and competitive standard (local/regional amateur, national amateur and professional) was conducted. Eighty-seven percent (n = 396) of strongman athletes reported that they used a taper. Athletes stated that their typical taper length was 8.6 ± 5.0 days, with the step taper the most commonly performed taper (52%). Training volume decreased during the taper by 45.5 ± 12.9%, and all training ceased 3.9 ± 1.8 days out from competition. Typically, athletes reported that training frequency and training duration stayed the same or decreased and training intensity decreased to around 50% in the last week. Athletes generally stated that tapering was performed to achieve recovery, rest, and peak performance; the deadlift, yoke walk, and stone lifts/work took longer to recover from than other lifts; assistance exercises were reduced or removed in the taper; massage, foam rolling, nutritional changes, and static stretching were strategies used in the taper; and, poor tapering occurred when athletes trained too heavy/hard or had too short a taper. These data will assist strongman athletes and coaches in the optimization of tapering variables leading to more peak performances. Future research could investigate the priming and preactivation strategies strongman athletes use on competition day.

Method and system for an automated tool for en route traffic controllers

NASA Technical Reports Server (NTRS)

Erzberger, Heinz (Inventor); McNally, B. David (Inventor)

2001-01-01

A method and system for a new automation tool for en route air traffic controllers first finds all aircraft flying on inefficient routes, then determines whether it is possible to save time by bypassing some route segments, and finally whether the improved route is free of conflicts with other aircraft. The method displays all direct-to eligible aircraft to an air traffic controller in a list sorted by highest time savings. By allowing the air traffic controller to easily identify and work with the highest pay-off aircraft, the method of the present invention contributes to a significant increase in both air traffic controller and aircraft productivity. A graphical computer interface (GUI) is used to enable the air traffic controller to send the aircraft direct to a waypoint or fix closer to the destination airport by a simple point and click action.

Method and System For an Automated Tool for En Route Traffic Controllers

NASA Technical Reports Server (NTRS)

Erzberger, Heinz (Inventor); McNally, B. David (Inventor)

2001-01-01

A method and system for a new automation tool for en route air traffic controllers first finds all aircraft flying on inefficient routes, then determines whether it is possible to save time by bypassing some route segments, and finally whether the improved route is free of conflicts with other aircraft. The method displays all direct-to eligible aircraft to an air traffic controller in a list sorted by highest time savings. By allowing the air traffic controller to easily identify and work with the highest pay-off aircraft, the method of the present invention contributes to a significant increase in both air traffic controller and aircraft productivity. A graphical computer interface (GUI) is used to enable the air traffic controller to send the aircraft direct to a waypoint or fix closer to the destination airport by a simple point and click action.

Problems in air traffic management. I., Longitudinal prediction of effectiveness of air traffic controllers.

DOT National Transportation Integrated Search

1961-12-01

Current (1961) job performance evaluations and medical history data were obtained for 149 of 197 men trained in air traffic control work in 1956. Evaluations of psychological test and biographical data collected at the time they went through training...

Automated Air Traffic Control Operations with Weather and Time-Constraints: A First Look at (Simulated) Far-Term Control Room Operations

NASA Technical Reports Server (NTRS)

Prevot, Thomas; Homola, Jeffrey R.; Martin, Lynne H.; Mercer, Joey S.; Cabrall, Christopher C.

2011-01-01

In this paper we discuss results from a recent high fidelity simulation of air traffic control operations with automated separation assurance in the presence of weather and time-constraints. We report findings from a human-in-the-loop study conducted in the Airspace Operations Laboratory (AOL) at the NASA Ames Research Center. During four afternoons in early 2010, fifteen active and recently retired air traffic controllers and supervisors controlled high levels of traffic in a highly automated environment during three-hour long scenarios, For each scenario, twelve air traffic controllers operated eight sector positions in two air traffic control areas and were supervised by three front line managers, Controllers worked one-hour shifts, were relieved by other controllers, took a 3D-minute break, and worked another one-hour shift. On average, twice today's traffic density was simulated with more than 2200 aircraft per traffic scenario. The scenarios were designed to create peaks and valleys in traffic density, growing and decaying convective weather areas, and expose controllers to heavy and light metering conditions. This design enabled an initial look at a broad spectrum of workload, challenge, boredom, and fatigue in an otherwise uncharted territory of future operations. In this paper we report human/system integration aspects, safety and efficiency results as well as airspace throughput, workload, and operational acceptability. We conclude that, with further refinements. air traffic control operations with ground-based automated separation assurance can be an effective and acceptable means to routinely provide very high traffic throughput in the en route airspace.

Improving the effectiveness of nighttime temporary traffic control warning devices, volume 1 : evaluation of lights on nighttime work zone channelization devices.

DOT National Transportation Integrated Search

2013-10-01

Currently, the Illinois Department of Transportation (IDOT) is one of the few state transportation agencies that : require warning lights on nighttime work zone channelization devices, such as drums and barricades. The intent : of the steady-burn, am...

30 CFR 57.9100 - Traffic control.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Dumping Traffic Safety § 57.9100 Traffic control. To provide for the safe movement of self-propelled... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Traffic control. 57.9100 Section 57.9100 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE...

30 CFR 57.9100 - Traffic control.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Dumping Traffic Safety § 57.9100 Traffic control. To provide for the safe movement of self-propelled... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Traffic control. 57.9100 Section 57.9100 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE...

30 CFR 56.9100 - Traffic control.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Dumping Traffic Safety § 56.9100 Traffic control. To provide for the safe movement of self-propelled... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Traffic control. 56.9100 Section 56.9100 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE...

30 CFR 56.9100 - Traffic control.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Traffic control. 56.9100 Section 56.9100 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... Dumping Traffic Safety § 56.9100 Traffic control. To provide for the safe movement of self-propelled...

30 CFR 56.9100 - Traffic control.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Traffic control. 56.9100 Section 56.9100 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... Dumping Traffic Safety § 56.9100 Traffic control. To provide for the safe movement of self-propelled...

30 CFR 56.9100 - Traffic control.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Traffic control. 56.9100 Section 56.9100 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... Dumping Traffic Safety § 56.9100 Traffic control. To provide for the safe movement of self-propelled...

30 CFR 57.9100 - Traffic control.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Traffic control. 57.9100 Section 57.9100 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... Dumping Traffic Safety § 57.9100 Traffic control. To provide for the safe movement of self-propelled...

30 CFR 57.9100 - Traffic control.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Traffic control. 57.9100 Section 57.9100 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... Dumping Traffic Safety § 57.9100 Traffic control. To provide for the safe movement of self-propelled...

An intelligent decision support system for work zone traffic management and planning : executive summary report.

DOT National Transportation Integrated Search

2004-01-01

Problem: Periodic resurfacing, rehabilitation, restoration, and reconstruction work is needed on the aging highway system in the state of Ohio to maintain a desired level of service for the traveling public. However, temporary work zones on highways ...

Vibration-Assisted Femtosecond Laser Drilling with Controllable Taper Angles for AMOLED Fine Metal Mask Fabrication.

PubMed

Choi, Wonsuk; Kim, Hoon Young; Jeon, Jin Woo; Chang, Won Seok; Cho, Sung-Hak

2017-02-21

This study investigates the effect of focal plane variation using vibration in a femtosecond laser hole drilling process on Invar alloy fabrication quality for the production of fine metal masks (FMMs). FMMs are used in the red, green, blue (RGB) evaporation process in Active Matrix Organic Light-Emitting Diode (AMOLED) manufacturing. The taper angle of the hole is adjusted by attaching the objective lens to a micro-vibrator and continuously changing the focal plane position. Eight laser pulses were used to examine how the hole characteristics vary with the first focal plane's position, where the first pulse is focused at an initial position and the focal planes of subsequent pulses move downward. The results showed that the hole taper angle can be controlled by varying the amplitude of the continuously operating vibrator during femtosecond laser hole machining. The taper angles were changed between 31.8° and 43.9° by adjusting the vibrator amplitude at a frequency of 100 Hz. Femtosecond laser hole drilling with controllable taper angles is expected to be used in the precision micro-machining of various smart devices.

77 FR 28455 - National Standards for Traffic Control Devices; the Manual on Uniform Traffic Control Devices for...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-14

... Options for design and applications of traffic control devices, this Manual should not be considered a... application of traffic control devices, as well as in the location and design of roads and streets that the..., while this Manual provides Standards, Guidance, and Options for design and applications of traffic...

Design and evaluation of an air traffic control Final Approach Spacing Tool

NASA Technical Reports Server (NTRS)

Davis, Thomas J.; Erzberger, Heinz; Green, Steven M.; Nedell, William

1991-01-01

This paper describes the design and simulator evaluation of an automation tool for assisting terminal radar approach controllers in sequencing and spacing traffic onto the final approach course. The automation tool, referred to as the Final Approach Spacing Tool (FAST), displays speed and heading advisories for arriving aircraft as well as sequencing information on the controller's radar display. The main functional elements of FAST are a scheduler that schedules and sequences the traffic, a four-dimensional trajectory synthesizer that generates the advisories, and a graphical interface that displays the information to the controller. FAST has been implemented on a high-performance workstation. It can be operated as a stand-alone in the terminal radar approach control facility or as an element of a system integrated with automation tools in the air route traffic control center. FAST was evaluated by experienced air traffic controllers in a real-time air traffic control simulation. simulation results summarized in the paper show that the automation tools significantly reduced controller work load and demonstrated a potential for an increase in landing rate.

An observation tool to study air traffic control and flightdeck collaboration.

PubMed

Cox, Gemma; Sharples, Sarah; Stedmon, Alex; Wilson, John

2007-07-01

The complex systems of the flightdeck (FD) and the Air Traffic Control Centre (ATC) are characterised by numerous concurrently operating and interacting communication channels between people and between people and machines/computer systems. This paper describes work in support of investigating the impact of changes to technologies and responsibilities within this system with respect to human factors. It focuses primarily on the introduction of datalink (text-based communication rather than traditional radio communication) and the move towards freeflight (pilot-mediated air traffic control). Air traffic management investigations have outlined these specific changes as strategies to enable further increases in the volume of air traffic. A systems approach was taken and field studies were conducted. Small numbers of domain experts such as air traffic controllers (ATCOs) were involved in the field-based observations of how people interact with systems and each other. This paper summarises the overall research approach taken and then specifically reports on the field-based observations including the justification, development, and findings of the observation tool used. The observation tool examined information propagation through the air traffic control-flightdeck (ATC-FD) system, and resulted in models of possible information trajectories through the system.

Reduction of speed in work zones using ITS DMS instant feedback to drivers : vehicle speed versus traffic fine.

DOT National Transportation Integrated Search

2014-08-01

Accidents in work zones produced 17 fatalities in Arizona and 840 fatalities and over 40,000 injuries : nationally in 2009. Motorists nationwide can expect to drive through one active work zone for every 100 : miles driven on the National Highway Sys...

Electroacupuncture for tapering off long-term benzodiazepine use: study protocol of randomized controlled trial.

PubMed

Yeung, Wing-Fai; Chung, Ka-Fai; Zhang, Zhang-Jin; Chan, Wai-Chi; Zhang, Shi-Ping; Ng, Roger Man-Kin; Chan, Connie Lai-Wah; Ho, Lai-Ming; Yu, Yee-Man; Lao, Li-Xing

2017-03-31

Conventional approaches for benzodiazepine tapering have their limitations. Anecdotal studies have shown that acupuncture is a potential treatment for facilitating successful benzodiazepine tapering. As of today, there was no randomized controlled trial examining its efficacy and safety. The purpose of the study is to evaluate the efficacy of using electroacupuncture as an adjunct treatment to gradual tapering of benzodiazepine doses in complete benzodiazepine cessation in long-term benzodiazepine users. The study protocol of a randomized, assessor- and subject-blinded, controlled trial is presented. One hundred and forty-four patients with histories of using benzodiazepines in ≥50% of days for more than 3 months will be randomly assigned in a 1:1 ratio to receive either electroacupuncture or placebo electroacupuncture combined with gradual benzodiazepine tapering schedule. Both experimental and placebo treatments will be delivered twice per week for 4 weeks. Major assessments will be conducted at baseline, week 6 and week 16 post-randomization. Primary outcome is the cessation rate of benzodiazepine use. Secondary outcomes include the percentage change in the doses of benzodiazepine usage and the severity of withdrawal symptoms experienced based on the Benzodiazepine Withdrawal Symptom Questionnaire, insomnia as measured by the Insomnia Severity Index, and anxiety and depressive symptoms as evaluated by the Hospital Anxiety and Depression Scale. Adverse events will also be measured at each study visit. Results of this study will provide high quality evidence of the efficacy and safety of electroacupuncture as an adjunct treatment for benzodiazepine tapering in long-term users. ClinicalTrials.gov NCT02475538 .

From Cellular Attractor Selection to Adaptive Signal Control for Traffic Networks.

PubMed

Tian, Daxin; Zhou, Jianshan; Sheng, Zhengguo; Wang, Yunpeng; Ma, Jianming

2016-03-14

The management of varying traffic flows essentially depends on signal controls at intersections. However, design an optimal control that considers the dynamic nature of a traffic network and coordinates all intersections simultaneously in a centralized manner is computationally challenging. Inspired by the stable gene expressions of Escherichia coli in response to environmental changes, we explore the robustness and adaptability performance of signalized intersections by incorporating a biological mechanism in their control policies, specifically, the evolution of each intersection is induced by the dynamics governing an adaptive attractor selection in cells. We employ a mathematical model to capture such biological attractor selection and derive a generic, adaptive and distributed control algorithm which is capable of dynamically adapting signal operations for the entire dynamical traffic network. We show that the proposed scheme based on attractor selection can not only promote the balance of traffic loads on each link of the network but also allows the global network to accommodate dynamical traffic demands. Our work demonstrates the potential of bio-inspired intelligence emerging from cells and provides a deep understanding of adaptive attractor selection-based control formation that is useful to support the designs of adaptive optimization and control in other domains.

5 CFR 842.207 - Air traffic controllers.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 5 Administrative Personnel 2 2014-01-01 2014-01-01 false Air traffic controllers. 842.207 Section... (CONTINUED) FEDERAL EMPLOYEES RETIREMENT SYSTEM-BASIC ANNUITY Eligibility § 842.207 Air traffic controllers... misconduct, is entitled to an annuity— (1) After completing 25 years of service as an air traffic controller...

5 CFR 842.207 - Air traffic controllers.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 5 Administrative Personnel 2 2013-01-01 2013-01-01 false Air traffic controllers. 842.207 Section... (CONTINUED) FEDERAL EMPLOYEES RETIREMENT SYSTEM-BASIC ANNUITY Eligibility § 842.207 Air traffic controllers... misconduct, is entitled to an annuity— (1) After completing 25 years of service as an air traffic controller...

5 CFR 842.207 - Air traffic controllers.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 5 Administrative Personnel 2 2011-01-01 2011-01-01 false Air traffic controllers. 842.207 Section... (CONTINUED) FEDERAL EMPLOYEES RETIREMENT SYSTEM-BASIC ANNUITY Eligibility § 842.207 Air traffic controllers... misconduct, is entitled to an annuity— (1) After completing 25 years of service as an air traffic controller...

5 CFR 842.207 - Air traffic controllers.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Air traffic controllers. 842.207 Section... (CONTINUED) FEDERAL EMPLOYEES RETIREMENT SYSTEM-BASIC ANNUITY Eligibility § 842.207 Air traffic controllers... misconduct, is entitled to an annuity— (1) After completing 25 years of service as an air traffic controller...

Stress in air traffic controllers : comparison of two air route traffic control centers on different shift rotation patterns.

DOT National Transportation Integrated Search

1975-01-01

Stress in 23 air traffic controllers (ATCS) at Atlanta Air Route Traffic Control Center (ATL) on the straight 5-day shift rotation schedule was compared with stress in 23 ATCS's on the 2-2-1 shift rotation schedule at Fort Worth Air Route Traffic Con...

Musculoskeletal disorders among female and male air traffic controllers performing identical and demanding computer work.

PubMed

Arvidsson, I; Arvidsson, M; Axmon, A; Hansson, G-A; Johansson, C R; Skerfving, S

2006-09-15

Operators with identical, demanding computer work (90 female and 97 male air traffic controllers) were found to have high prevalences of disorders (assessed by questionnaire and physical examination) in neck, shoulders and upper back. In spite of the identical work, the women displayed higher prevalences than the men (e.g. neck diagnoses 21% vs. 4%). Disorders in elbows, wrists and hands were less common, with similar rates in both genders. Generally, the psychosocial work environment (assessed by questionnaire) was found to be good, but with large inter-individual variation. Women experienced lower decision latitude than men, particularly regarding influence and freedom at work, but perceived higher social support. Physically, the work was characterized by relatively low angular velocities of upper arms (measured by inclinometry) and wrists (right: < 1 degrees/s during 19% of time, measuring by goniometry), dynamic muscular activities and high time fractions of rest in the trapezius and forearm extensor muscles (measuring by electromyography). There were only minor differences between the genders.

Effect of apical size and taper on volume of irrigant delivered at working length with apical negative pressure at different root curvatures.

PubMed

de Gregorio, Cesar; Arias, Ana; Navarrete, Natalia; Del Rio, Veronica; Oltra, Enrique; Cohenca, Nestor

2013-01-01

The purpose of this investigation was to determine the effect that apical preparation size and preparation taper have on the volume of irrigant delivered at the working length for different canal curvatures using apical negative pressure irrigation. One hundred fifty-five human teeth (55 maxillary canines and 100 mandibular molars) were used in this study. Root canals were prepared with rotary instruments to a size 35.04 and separated into 3 experimental groups according to their degree of curvature: group A (n = 50) included canal curvatures ranging from 0° to 10°, group B (n = 50) from 11° to 30°, and group C (n = 50) from 31° to 65°. Samples of each curvature group were further randomized to experimental subgroups according to the apical size and taper as follow: 35.06, 40.04, 40.06, 45.04, and 45.06. The apical third was irrigated using a microcannula and the volume of NaOCl suctioned at the working length under negative pressure was measured over a period of 30 seconds using a fluid recovery trap. Positive controls consisted of measuring the maximum volume of 5.25% NaOCl capable of being suctioned by the microcannula from an open glass vial over 30 seconds. Negative control was the volume of irrigant aspirated by the microcannula with a preparation size of 25.04 over 30 seconds. The volume of irrigant was significantly greater when the apical preparation size increased from 35.06 to 40.04. As the apical preparation taper increased further from 40.04 to 40.06, the volume of irrigant significantly improved in group B, but it was not significant in group A. Apical preparation sizes greater than 40.06 did not show an increase of the volume of irrigant aspirated. The degree of root canal curvature decreased the volume of irrigant at the working length for a given apical size and taper. An apical preparation of 40.06 significantly increased the volume and exchange of irrigant at the working length regardless of curvature. Copyright © 2013 American

Evaluation of warning lights on maintenance of traffic devices and development of possible alternatives : [summary].

DOT National Transportation Integrated Search

2013-01-01

Orange plastic drums are common on Florida roadways, warning motorists and guiding them safely through work zones. The orange color is mandated by the Manual on Uniform Traffic Control Devices, which also requires that drums bear retroreflective whit...

Affect adjective check list assessment of mood variations in air traffic controllers.

DOT National Transportation Integrated Search

1971-04-01

Three groups of subjects completed Composite Mood Adjective Check Lists (CMACL) before and after selected shifts at two air traffic control (ATC) facilities as part of a multi-discipline study of stress in ATC work. : At one facility, a high traffic ...

Vibration-Assisted Femtosecond Laser Drilling with Controllable Taper Angles for AMOLED Fine Metal Mask Fabrication

PubMed Central

Choi, Wonsuk; Kim, Hoon Young; Jeon, Jin Woo; Chang, Won Seok; Cho, Sung-Hak

2017-01-01

This study investigates the effect of focal plane variation using vibration in a femtosecond laser hole drilling process on Invar alloy fabrication quality for the production of fine metal masks (FMMs). FMMs are used in the red, green, blue (RGB) evaporation process in Active Matrix Organic Light-Emitting Diode (AMOLED) manufacturing. The taper angle of the hole is adjusted by attaching the objective lens to a micro-vibrator and continuously changing the focal plane position. Eight laser pulses were used to examine how the hole characteristics vary with the first focal plane’s position, where the first pulse is focused at an initial position and the focal planes of subsequent pulses move downward. The results showed that the hole taper angle can be controlled by varying the amplitude of the continuously operating vibrator during femtosecond laser hole machining. The taper angles were changed between 31.8° and 43.9° by adjusting the vibrator amplitude at a frequency of 100 Hz. Femtosecond laser hole drilling with controllable taper angles is expected to be used in the precision micro-machining of various smart devices. PMID:28772571

Surveying air traffic control specialist perception of scheduling regulations

NASA Astrophysics Data System (ADS)

Thompson, Darrius E.

While there have been several studies conducted on air traffic controller fatigue, there is a lack of research on the subject since the scheduling policy changes that took place in 2012. The effectiveness of these changes has yet to be measured. The goal of this study was to investigate air traffic control specialist views towards the number of hours scheduled between shifts, changes in perception since 2012 regulation changes, and external factors that impact fatigue. A total of 54 FAA air traffic control specialist completed an online questionnaire. The results from the survey showed that the majority of respondents felt the 2012 regulation changes were not sufficient to address fatigue issues, and work with some amount sleep deprivation. The factors that appeared to have the most significant effect on fatigue included facility level, age group, availability of recuperative breaks, and children under 18 in the home.

The Impact of Trajectory Prediction Uncertainty on Air Traffic Controller Performance and Acceptability

NASA Technical Reports Server (NTRS)

Mercer, Joey S.; Bienert, Nancy; Gomez, Ashley; Hunt, Sarah; Kraut, Joshua; Martin, Lynne; Morey, Susan; Green, Steven M.; Prevot, Thomas; Wu, Minghong G.

2013-01-01

A Human-In-The-Loop air traffic control simulation investigated the impact of uncertainties in trajectory predictions on NextGen Trajectory-Based Operations concepts, seeking to understand when the automation would become unacceptable to controllers or when performance targets could no longer be met. Retired air traffic controllers staffed two en route transition sectors, delivering arrival traffic to the northwest corner-post of Atlanta approach control under time-based metering operations. Using trajectory-based decision-support tools, the participants worked the traffic under varying levels of wind forecast error and aircraft performance model error, impacting the ground automations ability to make accurate predictions. Results suggest that the controllers were able to maintain high levels of performance, despite even the highest levels of trajectory prediction errors.

Cyclic fatigue resistance of ProTaper Next nickel-titanium rotary files.

PubMed

Elnaghy, A M

2014-11-01

To compare the cyclic fatigue resistance of ProTaper Next files (PTN; Dentsply Maillefer, Ballaigues, Switzerland) with Twisted Files (TF; SybronEndo, Orange, CA, USA), HyFlex CM (HF; ColténeEndo/Whaledent, Inc, Cuyahoga Falls, OH, USA) and ProTaper Universal (PT; Dentsply Maillefer). Size 25, .06 taper for PTN X2, TF, HF and PT F1 size 20, .07 taper were rotated in simulated canals until failure, and the number of cycles to failure (NCF) was recorded to evaluate their cyclic fatigue resistance. A scanning electron microscope was used to characterize the topographic features of the fracture surfaces of broken files. The data of the NCF and fragment length values were analysed statistically using one-way analysis of variance and Tukey post hoc tests. Statistical significance level was set at P < 0.05. Twisted Files had a significantly higher resistance to cyclic fatigue than the other instruments (P < 0.05). No significant difference was found in NCF between PTN and HF (P > 0.05); however, there was a significant difference (P < 0.05) of both these systems with PT, which exhibited the lowest mean NCF. The ranking in the NCF values was: TF > PTN > HF > PT. The fracture cross-sections of all brands revealed similar fractographic features, including crack origins, fatigue zone and an overload fast fracture zone. The new ProTaper Next had greater resistance to cyclic fatigue compared with ProTaper and HyFlex CM but not the Twisted Files. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Shift work, age, and performance : investigation of the 2-2-1 shift schedule used in air traffic control facilities. I., The sleep/wake cycle.

DOT National Transportation Integrated Search

1995-05-01

Air Traffic Control Specialists (ATCS) work rotating shift schedules for most of their careers. Specifically, many work a counterclockwise rotating shift schedule, called the 2-2-1, or some variation of the schedule. The 2-2-1 involves rotating from ...

[Application of hand-use ProTaper instruments in endodontic treatment of molar canals].

PubMed

Ma, Sui-qi; Xie, Qian; Zhou, Yin-feng

2010-07-01

To evaluate the application of hand-use ProTaper instruments in endodontic treatment of molar canals. A total of 203 permanent molars were randomly divided into the experimental group (99 molars) and control group (104 molars) prepared by hand-use ProTaper instruments and standard stainless steel K-file, respectively. The molars in the two groups were obturated by cold lateral condensation technique. The root canal preparation and obturation were evaluated by radiograph, and the working time of preparation and post-operative emergencies were analyzed. The preparation time in the experimental group was obviously shorter than that in the control group (P<0.01). The rate of satisfactory effect was significantly higher in the experimental group than in the control group (P<0.01), and the rate of post-operative emergencies was significantly lower in the experimental group (P<0.01). The application of hand-use ProTaper instruments may improve the effect of root canal treatment of the molars and shorten the working time and reduce the post-operative emergencies.

Optimal Control of Hybrid Systems in Air Traffic Applications

NASA Astrophysics Data System (ADS)

Kamgarpour, Maryam

Growing concerns over the scalability of air traffic operations, air transportation fuel emissions and prices, as well as the advent of communication and sensing technologies motivate improvements to the air traffic management system. To address such improvements, in this thesis a hybrid dynamical model as an abstraction of the air traffic system is considered. Wind and hazardous weather impacts are included using a stochastic model. This thesis focuses on the design of algorithms for verification and control of hybrid and stochastic dynamical systems and the application of these algorithms to air traffic management problems. In the deterministic setting, a numerically efficient algorithm for optimal control of hybrid systems is proposed based on extensions of classical optimal control techniques. This algorithm is applied to optimize the trajectory of an Airbus 320 aircraft in the presence of wind and storms. In the stochastic setting, the verification problem of reaching a target set while avoiding obstacles (reach-avoid) is formulated as a two-player game to account for external agents' influence on system dynamics. The solution approach is applied to air traffic conflict prediction in the presence of stochastic wind. Due to the uncertainty in forecasts of the hazardous weather, and hence the unsafe regions of airspace for aircraft flight, the reach-avoid framework is extended to account for stochastic target and safe sets. This methodology is used to maximize the probability of the safety of aircraft paths through hazardous weather. Finally, the problem of modeling and optimization of arrival air traffic and runway configuration in dense airspace subject to stochastic weather data is addressed. This problem is formulated as a hybrid optimal control problem and is solved with a hierarchical approach that decouples safety and performance. As illustrated with this problem, the large scale of air traffic operations motivates future work on the efficient

Traffic control procedures for emergency responders.

DOT National Transportation Integrated Search

2006-10-01

The objective of this study was to develop a training course and handbook to guide on-scene emergency responders responsible for controlling traffic during a roadway crash and subsequent clearance. : Traffic control is an essential component of incid...

Fixed Point Learning Based Intelligent Traffic Control System

NASA Astrophysics Data System (ADS)

Zongyao, Wang; Cong, Sui; Cheng, Shao

2017-10-01

Fixed point learning has become an important tool to analyse large scale distributed system such as urban traffic network. This paper presents a fixed point learning based intelligence traffic network control system. The system applies convergence property of fixed point theorem to optimize the traffic flow density. The intelligence traffic control system achieves maximum road resources usage by averaging traffic flow density among the traffic network. The intelligence traffic network control system is built based on decentralized structure and intelligence cooperation. No central control is needed to manage the system. The proposed system is simple, effective and feasible for practical use. The performance of the system is tested via theoretical proof and simulations. The results demonstrate that the system can effectively solve the traffic congestion problem and increase the vehicles average speed. It also proves that the system is flexible, reliable and feasible for practical use.

From Cellular Attractor Selection to Adaptive Signal Control for Traffic Networks

PubMed Central

Tian, Daxin; Zhou, Jianshan; Sheng, Zhengguo; Wang, Yunpeng; Ma, Jianming

2016-01-01

The management of varying traffic flows essentially depends on signal controls at intersections. However, design an optimal control that considers the dynamic nature of a traffic network and coordinates all intersections simultaneously in a centralized manner is computationally challenging. Inspired by the stable gene expressions of Escherichia coli in response to environmental changes, we explore the robustness and adaptability performance of signalized intersections by incorporating a biological mechanism in their control policies, specifically, the evolution of each intersection is induced by the dynamics governing an adaptive attractor selection in cells. We employ a mathematical model to capture such biological attractor selection and derive a generic, adaptive and distributed control algorithm which is capable of dynamically adapting signal operations for the entire dynamical traffic network. We show that the proposed scheme based on attractor selection can not only promote the balance of traffic loads on each link of the network but also allows the global network to accommodate dynamical traffic demands. Our work demonstrates the potential of bio-inspired intelligence emerging from cells and provides a deep understanding of adaptive attractor selection-based control formation that is useful to support the designs of adaptive optimization and control in other domains. PMID:26972968

Near-road measurements for nitrogen dioxide and its association with traffic exposure zones

EPA Science Inventory

Near-road measurements for nitrogen dioxide (NO₂) using passive air samplers were collected weekly in traffic exposure zones (TEZs) in the Research Triangle area of North Carolina (USA) during Fall 2014. Land use regression (LUR) analysis and pairwise comparisons of T...

Iowa Work Zone Fatalities

DOT National Transportation Integrated Search

2011-01-01

From March through November, the Iowa DOT may have up to 500 road construction work zones, and each of the department's maintenance garages may establish one or more short-term work zones per day. Couple that with the work of cities and counties, and...

Traffic control concepts for incident clearance

DOT National Transportation Integrated Search

2009-01-01

This document discusses various aspects of traffic control for incidents with the focus on the traffic control roles and responsibilities of the responders as well as the safety of the responders and the motoring public. It also recognizes that activ...

Exposure to lateral collision in signalized intersections with protected left turn under different traffic control strategies.

PubMed

Midenet, Sophie; Saunier, Nicolas; Boillot, Florence

2011-11-01

This paper proposes an original definition of the exposure to lateral collision in signalized intersections and discusses the results of a real world experiment. This exposure is defined as the duration of situations where the stream that is given the right-of-way goes through the conflict zone while road users are waiting in the cross-traffic approach. This measure, obtained from video sensors, makes it possible to compare different operating conditions such as different traffic signal strategies. The data from a real world experiment is used, where the adaptive real-time strategy CRONOS (ContRol Of Networks by Optimization of Switchovers) and a time-plan strategy with vehicle-actuated ranges alternately controlled an isolated intersection near Paris. Hourly samples with similar traffic volumes are compared and the exposure to lateral collision is different in various areas of the intersection and various traffic conditions for the two strategies. The total exposure under peak hour traffic conditions drops by roughly 5 min/h with the CRONOS strategy compared to the time-plan strategy, which occurs mostly on entry streams. The results are analyzed through the decomposition of cycles in phase sequences and recommendations are made for traffic control strategies. Copyright © 2011 Elsevier Ltd. All rights reserved.

Evaluation of the effects of school zone signs and markings on speed reduction: a driving simulator study.

PubMed

Zhao, Xiaohua; Li, Jiahui; Ma, Jianming; Rong, Jian

2016-01-01

Traffic control devices are one of the most significant factors affecting driving behavior. In China, there is a lack of installation guidelines or standards for traffic control devices in school zones. In addition, little research has been done to examine the effects of traffic control devices on driving behavior. Few guidelines have been established for implementing traffic control devices in school zones in China. This research conducted a driving simulator experiment to assess the effects of school zone signs and markings for two different types of schools. The efficiency of these traffic control devices was evaluated using four variables derived from the driving simulation, including average speed, relative speed difference, standard deviation of acceleration, and 85th percentile speed. Results showed that traffic control devices such as the Flashing Beacon and School Crossing Ahead Warning Assembly, the Reduce Speed and School Crossing Warning Assembly, and the School Crossing Ahead Pavement Markings were recommended for school zones adjacent to a major multilane roadway, which is characterized by a median strip, high traffic volume, high-speed traffic and the presence of pedestrian crossing signals. The School Crossing Ahead Pavement Markings were recommended for school zones on a minor two-lane roadway, which is characterized by low traffic volume, low speed, and no pedestrian crossing signals.

Fuel conditioning facility zone-to-zone transfer administrative controls.

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

Pope, C. L.

2000-06-21

The administrative controls associated with transferring containers from one criticality hazard control zone to another in the Argonne National Laboratory (ANL) Fuel Conditioning Facility (FCF) are described. FCF, located at the ANL-West site near Idaho Falls, Idaho, is used to remotely process spent sodium bonded metallic fuel for disposition. The process involves nearly forty widely varying material forms and types, over fifty specific use container types, and over thirty distinct zones where work activities occur. During 1999, over five thousand transfers from one zone to another were conducted. Limits are placed on mass, material form and type, and container typesmore » for each zone. Ml material and containers are tracked using the Mass Tracking System (MTG). The MTG uses an Oracle database and numerous applications to manage the database. The database stores information specific to the process, including material composition and mass, container identification number and mass, transfer history, and the operators involved in each transfer. The process is controlled using written procedures which specify the zone, containers, and material involved in a task. Transferring a container from one zone to another is called a zone-to-zone transfer (ZZT). ZZTs consist of four distinct phases, select, request, identify, and completion.« less

Selection of applicants for the air traffic controller occupation.

DOT National Transportation Integrated Search

1981-07-01

This report covers personnel research efforts during the past nine years directed toward improving the selection of applicants to work in the Air Traffic Control occupation. The report summarizes the various research efforts and makes specific recomm...

Overview of Airport Surface Traffic Control - Present and Future

DOT National Transportation Integrated Search

1975-09-01

The Airport Surface Traffic Control System, an integral part of the nation's Air Traffic Control System, is specifically concerned with the safe and efficient control of airport airside surface traffic. The current status of airport surface traffic c...

47 CFR 80.325 - Control of distress traffic.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Control of distress traffic. 80.325 Section 80... Safety Procedures § 80.325 Control of distress traffic. (a) Distress traffic consists of all messages relating to the immediate assistance required by the mobile station in distress. In distress traffic, the...

Buffalo Air Traffic Control Tower Operations Analysis.

DOT National Transportation Integrated Search

1981-09-01

This report provides a description of the non-surveillance aspects of the FAA air traffic control facility operation at Greater Buffalo International Airport from the air traffic controller's point of view. It includes photographs of all controller c...

Comparative evaluation of apically extruded debris with V-Taper, ProTaper Next, and the Self-adjusting File systems.

PubMed

Vyavahare, Nishant K; Raghavendra, Srinidhi Surya; Desai, Niranjan N

2016-01-01

Complete cleaning of the root canal is the goal for ensuring success in endodontics. Removal of debris plays an important role in achieving this goal. In spite of advancements in instrument design, apical extrusion of debris remains a source of inflammation in the periradicular region. To comparatively evaluate the amount of apically extruded debris with V-Taper, ProTaper Next, and the self-adjusting File (SAF) system. Sixty-four extracted human mandibular teeth with straight root canals were taken. Access openings were done and working length determined. The samples were randomly divided into three groups: Group I - V-Taper files (n = 20), Group II - ProTaper Next (n = 20), Group III - SAF (n = 20). Biomechanical preparation was completed and the debris collected in vials to be quantitatively determined. The data obtained was statistically analyzed using ANOVA and post hoc Tukey's test. All the specimens showed apical debris extrusion. SAF showed significantly less debris extrusion compared to V-Taper and ProTaper Next (P < 0.001). Among Groups I and II, ProTaper Next showed lesser debris extrusion as compared to V-Taper, but it was not significant (P = 0.124). The SAF showed least amount of apical debris extrusion when compared to newer rotary endodontic instruments. This indicates that the incidence of inter-treatment flare-ups due to debris extrusion would be less with the SAF.

Work zone safety analysis.

DOT National Transportation Integrated Search

2013-11-01

This report presents research performed analyzing crashes in work zones in the state of New Jersey so as to : identify critical areas in work zones susceptible to crashes and key factors that contribute to these crashes. A field : data collection on ...

Supercontinuum generation in an imaging fiber taper

NASA Astrophysics Data System (ADS)

Shi, Kebin; Omenetto, Fiorenzo G.; Liu, Zhiwen

2006-12-01

We report on supercontinuum generation in individual fibers of a commercial Schott imaging fiber taper. Supercontinuum spectrum covering a wavelength range from about 500 nm to 1 μm was obtained. Unlike conventional approaches which use either a single micro-structured photonic crystal fiber (PCF) or an individual fiber or PCF taper, the availability of many fibers in an imaging taper can open new possibilities to independently and controllably generate supercontinuum arrays.

Characterized Brillouin scattering in silica optical fiber tapers based on Brillouin optical correlation domain analysis.

PubMed

Zou, Weiwen; Jiang, Wenning; Chen, Jianping

2013-03-11

This paper demonstrates stimulated Brillouin scattering (SBS) characterization in silica optical fiber tapers drawn from commercial single mode optical fibers by hydrogen flame. They have different waist diameters downscaled from 5 μm to 42 μm. The fully-distributed SBS measurement along the fiber tapers is implemented by Brillouin optical correlation domain analysis technique with millimeter spatial resolution. It is found that the Brillouin frequency shift (BFS) in the waist of all fiber tapers is approximately the same (i.e., ~11.17 GHz at 1550 nm). However, the BFS is gradually reduced and the Brillouin gain decreases from the waist to the untapered zone in each fiber taper.

Use of police in work zones on highways in Virginia.

DOT National Transportation Integrated Search

2003-01-01

It is generally accepted that one of the most effective ways of controlling speed in a work zone is to have a staffed police car positioned at the beginning of the work zone with its lights flashing and radar on. Drivers detect the presence of police...

Broadcast control of air traffic

NASA Technical Reports Server (NTRS)

Litchford, G. B.

1971-01-01

Concepts of increased pilot participation in air traffic control are presented. The design of an air traffic control system for pilot usage is considered. The operating and safety benefits of LF/VLF approaches in comparison to current nonprecision approach procedures and systems are discussed. With a good national system plan, flight testing and validation, and the use of local differential, or general diurnal, corrections, the LF/VLF system would provide service superior to that presently available.

Near real-time traffic routing

NASA Technical Reports Server (NTRS)

Yang, Chaowei (Inventor); Xie, Jibo (Inventor); Zhou, Bin (Inventor); Cao, Ying (Inventor)

2012-01-01

A near real-time physical transportation network routing system comprising: a traffic simulation computing grid and a dynamic traffic routing service computing grid. The traffic simulator produces traffic network travel time predictions for a physical transportation network using a traffic simulation model and common input data. The physical transportation network is divided into a multiple sections. Each section has a primary zone and a buffer zone. The traffic simulation computing grid includes multiple of traffic simulation computing nodes. The common input data includes static network characteristics, an origin-destination data table, dynamic traffic information data and historical traffic data. The dynamic traffic routing service computing grid includes multiple dynamic traffic routing computing nodes and generates traffic route(s) using the traffic network travel time predictions.

Comparative evaluation of apically extruded debris with V-Taper, ProTaper Next, and the Self-adjusting File systems

PubMed Central

Vyavahare, Nishant K.; Raghavendra, Srinidhi Surya; Desai, Niranjan N.

2016-01-01

Background: Complete cleaning of the root canal is the goal for ensuring success in endodontics. Removal of debris plays an important role in achieving this goal. In spite of advancements in instrument design, apical extrusion of debris remains a source of inflammation in the periradicular region. Aim: To comparatively evaluate the amount of apically extruded debris with V-Taper, ProTaper Next, and the self-adjusting File (SAF) system. Materials and Methods: Sixty-four extracted human mandibular teeth with straight root canals were taken. Access openings were done and working length determined. The samples were randomly divided into three groups: Group I - V-Taper files (n = 20), Group II - ProTaper Next (n = 20), Group III - SAF (n = 20). Biomechanical preparation was completed and the debris collected in vials to be quantitatively determined. The data obtained was statistically analyzed using ANOVA and post hoc Tukey's test. Results: All the specimens showed apical debris extrusion. SAF showed significantly less debris extrusion compared to V-Taper and ProTaper Next (P < 0.001). Among Groups I and II, ProTaper Next showed lesser debris extrusion as compared to V-Taper, but it was not significant (P = 0.124). Conclusion: The SAF showed least amount of apical debris extrusion when compared to newer rotary endodontic instruments. This indicates that the incidence of inter-treatment flare-ups due to debris extrusion would be less with the SAF. PMID:27217636

Tapered capillary optics

DOEpatents

Hirsch, Gregory

1998-01-01

A metal or glass wire is etched with great precision into a very narrowly tapering cone which has the shape of the desired final capillary-optics bore. By controlling the rate of removal of the wire from an etchant bath, a carefully controlled taper is produced. A sensor measures the diameter of the wire as it leaves the surface of the etchant. This signal is used for feedback control of the withdrawal speed. The etched wire undergoes a treatment to produce an extremely low surface-roughness. The etched and smoothed wire is coated with the material of choice for optimizing the reflectivity of the radiation being focused. This could be a vacuum evaporation, sputtering, CVD or aqueous chemical process. The coated wire is either electroplated, built up with electroless plating, or encapsulated in a polymer cylinder such as epoxy to increase the diameter of the wire for easier handling and greater robustness. During this process, the wire is vertically oriented and tensioned to assure that the wire is absolutely straight. The coated and electroformed wire is bonded to a flat, rigid substrate and is then periodically segmented by cutting or etching a series of narrow slits or grooves into the wire. The wire is vertically oriented and tensioned during the bonding process to assure that it is straight. The original wire material is then chemically etched away through the slits or otherwise withdrawn to leave the hollow internal bore of the final tapered-capillary optical element.

Initial Air Traffic Control Training at Tartu Aviation College

DOT National Transportation Integrated Search

1997-01-01

A well developed air traffic control training system is vitally important for guaranteeing flight safety and the efficient provision of air traffic control services. During the Soviet era, air traffic control services in Estonia were provided by Aero...

Cognition and aging in a complex work environment: relationships with performance among air traffic control specialists.

PubMed

Becker, J T; Milke, R M

1998-10-01

Chronological age affects the performance of demanding cognitive tasks within the aviation environment. Within the domain of air traffic control (ATC), the ability to handle simultaneous visual and auditory input, or to return to a task after a break to complete another task, is critical to success and is the sort of cognitive function most affected by age. The limited available data suggest a strong relationship between age and job performance among ATC specialists, whether measured at the time of entry into the system or during the working lifetime of a full-performance-level controller. An analysis of the distribution of the ages of controllers currently in the system, and a projection for the years 2001 and 2006, leads to the conclusion that a high proportion of the ATC work force will be at risk for displaying age-related changes in job performance efficiency over the next 10 yr. It seems important, therefore, to determine the nature and extent of the age-related cognitive changes that can occur during the lifespan of a controller (i.e., 25-55 yr of age) and how these changes may affect job performance. The results of such an analysis should aid in the design and implementation of new control systems to minimize any deleterious effects of aging on performance.

A knowledge-based system for controlling automobile traffic

NASA Technical Reports Server (NTRS)

Maravas, Alexander; Stengel, Robert F.

1994-01-01

Transportation network capacity variations arising from accidents, roadway maintenance activity, and special events as well as fluctuations in commuters' travel demands complicate traffic management. Artificial intelligence concepts and expert systems can be useful in framing policies for incident detection, congestion anticipation, and optimal traffic management. This paper examines the applicability of intelligent route guidance and control as decision aids for traffic management. Basic requirements for managing traffic are reviewed, concepts for studying traffic flow are introduced, and mathematical models for modeling traffic flow are examined. Measures for quantifying transportation network performance levels are chosen, and surveillance and control strategies are evaluated. It can be concluded that automated decision support holds great promise for aiding the efficient flow of automobile traffic over limited-access roadways, bridges, and tunnels.

Analysis of Controller Communication in En Route Air Traffic Control.

ERIC Educational Resources Information Center

Seamster, Thomas L.; And Others

To contribute to an understanding of the elements of good air traffic controller communication with the objective of providing recommendations to improve controller communication training, two studies analyzed team communication, ground-air communication, and ground-line communication. The simulated and live traffic analyses examined established…

Traffic flow collection wireless sensor network node for intersection light control

NASA Astrophysics Data System (ADS)

Li, Xu; Li, Xue

2011-10-01

Wireless sensor network (WSN) is expected to be deployed in intersection to monitor the traffic flow continuously, and the monitoring datum can be used as the foundation of traffic light control. In this paper, a WSN based on ZigBee protocol for monitoring traffic flow is proposed. Structure, hardware and work flow of WSN nodes are designed. CC2431 from Texas Instrument is chosen as the main computational and transmission unit, and CC2591 as the amplification unit. The stability experiment and the actual environment experiment are carried out in the last of the paper. The results of experiments show that WSN has the ability to collect traffic flow information quickly and transmit the datum to the processing center in real time.

Next-generation smart traffic signals : RHODES with Intellidrive, the self-taught traffic control system.

DOT National Transportation Integrated Search

2009-01-01

Can a self-calibrating signal control system lead to wider adoption of adaptive traffic control systems? The focus of Next Generation of Smart Traffic Signals, an Exploratory Advanced Research (EAR) Program project, is a system that-with lit...

Rapid counterclockwise shift rotation in air traffic control: effects on sleep and night work.

PubMed

Signal, T Leigh; Gander, Philippa H

2007-09-01

In Air Traffic Control, counterclockwise rapidly rotating shift schedules are often employed but may result in significant sleep loss. This has potential consequences for performance, particularly if a night shift is worked. As part of a large-scale field study, the pattern of sleep across a 4-d counterclockwise, rapidly rotating schedule (afternoon, day, morning, night shift) was documented and relationships between prior sleep and performance during the night shift were investigated. There were 28 controllers who completed 4 periods of data collection which included 2 d before and 2 d after a 4-d shift cycle. Sleep was recorded using an actigraph and sleep diary, and performance on each night shift was measured three times using the Psychomotor Vigilance Task. Across the work week, sleep duration decreased largely due to earlier rise times associated with shift start times moving backward. In the short turn-around between the morning and night shift, 90% of controllers slept for an average of 2.2 h. Improved performance on the night shift was related only to longer periods of sleep the night prior. This study demonstrates that a 4-d counterclockwise, rapidly rotating schedule results in a progressive reduction in sleep and consequently the rapid accumulation of a sleep debt. To help maintain their performance on the night shift, it is recommended that controllers attempt to obtain at least 6 h sleep the night before a night shift. It is also recommended that ATC providers educate their workforce about this issue.

Polymer optical fiber tapering using hot water

NASA Astrophysics Data System (ADS)

Mizuno, Yosuke; Ujihara, Hiroki; Lee, Heeyoung; Hayashi, Neisei; Nakamura, Kentaro

2017-06-01

We perform a pilot trial of highly convenient taper fabrication for polymer optical fibers (POFs) using hot water. A ∼380-mm-long POF taper is successfully fabricated, and its ∼150-mm-long waist has a uniform outer diameter of ∼230 µm. The shape is in good agreement with the theoretical prediction. The optical loss dependence on the strain applied to the waist shows an interesting behavior exhibiting three regimes, the origins of which are inferred by microscopic observations. We then discuss the controllability of the taper length.

Distributed traffic signal control using fuzzy logic

NASA Technical Reports Server (NTRS)

Chiu, Stephen

1992-01-01

We present a distributed approach to traffic signal control, where the signal timing parameters at a given intersection are adjusted as functions of the local traffic condition and of the signal timing parameters at adjacent intersections. Thus, the signal timing parameters evolve dynamically using only local information to improve traffic flow. This distributed approach provides for a fault-tolerant, highly responsive traffic management system. The signal timing at an intersection is defined by three parameters: cycle time, phase split, and offset. We use fuzzy decision rules to adjust these three parameters based only on local information. The amount of change in the timing parameters during each cycle is limited to a small fraction of the current parameters to ensure smooth transition. We show the effectiveness of this method through simulation of the traffic flow in a network of controlled intersections.

Air Traffic Control Radar

NASA Image and Video Library

2003-08-13

An Air Traffic Control radar has been constructed at Shiloh for the NASA control tower at the Shuttle Landing Facility. It will be used by NASA and the Eastern Range for surveillance of controlled air space in Kennedy Space Center and Cape Canaveral Air Force Station restricted areas. Shiloh is on the northern end of Merritt Island.

Air Traffic Control Radar

NASA Image and Video Library

2003-08-13

An Air Traffic Control radar is being constructed at Shiloh for the NASA control tower at the Shuttle Landing Facility. It will be used by NASA and the Eastern Range for surveillance of controlled air space in Kennedy Space Center and Cape Canaveral Air Force Station restricted areas. Shiloh is on the northern end of Merritt Island.

Stress, anxiety, and the air traffic control specialist : some conclusions from a decade of research.

DOT National Transportation Integrated Search

1980-09-01

This paper summarizes a decade of research evaluating possible stress effects of work on Air Traffic Control Specialists (ATCSs).Studies were conducted at a variety of large and small air traffic facilities. A visit of several days to each facility w...

Work zone intrusion alarm effectiveness.

DOT National Transportation Integrated Search

2010-09-01

16. Abstract : The New Jersey Department of Transportation (NJDOT) commissioned a study to evaluate how : effective a work zone safety device known as the SonoBlaster! Work Zone Intrusion Alarm would be : in protecting maintenance workers fro...

Carbon monoxide exposure among police officers working in a traffic dense region of Southern India.

PubMed

Nair, A J; Nandini, M; Adappa, S; Mahabala, C

2017-01-01

Currently, in India, air pollution is widespread in urban areas where vehicles are major contributors. The aim of this study was to investigate the level of exposure in traffic police officers exposed to vehicle exhaust for less than 8 h/day. The specific objective of the study was to determine the levels of carboxyhaemoglobin (COHb) in these officers. The effect of exposure for 8 h/day is known, but shorter durations of chronic exposure need to be investigated, and there is a need to explore the policy options in this exposed population. This cross-sectional study, included non-smoking traffic police officers between 30 and 50 years of age working for more than 2 years in busy traffic junctions. The cases were sex matched with controls of same age group, working in offices at a teaching hospital. Venous blood was collected at the end of 3 h of duty for estimation of COHb among both the groups. The COHb levels were expressed as percentage values. Differences between the COHb levels among the traffic police officers and office workers were analysed using the Mann-Whitney U test and considered significant at p < 0.05. Traffic police officers had significantly elevated COHb levels compared with the controls; 76.5% of traffic police officers had COHb >2.5% compared with no office workers at this level and 41.2% of the police officers had COHb levels >4%. Overall, 53.8% of officers with COHb >2.5% reported headaches compared with 15.8% of officers with COHb <2.5%.

Parabolic tapers for overmoded waveguides

DOEpatents

Doane, J.L.

1983-11-25

A waveguide taper with a parabolic profile, in which the distance along the taper axis varies as the square of the tapered dimension, provides less mode conversion than equal length linear tapers and is easier to fabricate than other non-linear tapers.

Electromagnetic field tapering using all-dielectric gradient index materials.

PubMed

Yi, Jianjia; Piau, Gérard-Pascal; de Lustrac, André; Burokur, Shah Nawaz

2016-07-28

The concept of transformation optics (TO) is applied to control the flow of electromagnetic fields between two sections of different dimensions through a tapering device. The broadband performance of the field taper is numerically and experimentally validated. The taper device presents a graded permittivity profile and is fabricated through three-dimensional (3D) polyjet printing technology using low-cost all-dielectric materials. Calculated and measured near-field mappings are presented in order to validate the proposed taper. A good qualitative agreement is obtained between full-wave simulations and experimental tests. Such all-dielectric taper paves the way to novel types of microwave devices that can be easily fabricated through low-cost additive manufacturing processes.

Rotational flow in tapered slab rocket motors

NASA Astrophysics Data System (ADS)

Saad, Tony; Sams, Oliver C.; Majdalani, Joseph

2006-10-01

Internal flow modeling is a requisite for obtaining critical parameters in the design and fabrication of modern solid rocket motors. In this work, the analytical formulation of internal flows particular to motors with tapered sidewalls is pursued. The analysis employs the vorticity-streamfunction approach to treat this problem assuming steady, incompressible, inviscid, and nonreactive flow conditions. The resulting solution is rotational following the analyses presented by Culick for a cylindrical motor. In an extension to Culick's work, Clayton has recently managed to incorporate the effect of tapered walls. Here, an approach similar to that of Clayton is applied to a slab motor in which the chamber is modeled as a rectangular channel with tapered sidewalls. The solutions are shown to be reducible, at leading order, to Taylor's inviscid profile in a porous channel. The analysis also captures the generation of vorticity at the surface of the propellant and its transport along the streamlines. It is from the axial pressure gradient that the proper form of the vorticity is ascertained. Regular perturbations are then used to solve the vorticity equation that prescribes the mean flow motion. Subsequently, numerical simulations via a finite volume solver are carried out to gain further confidence in the analytical approximations. In illustrating the effects of the taper on flow conditions, comparisons of total pressure and velocity profiles in tapered and nontapered chambers are entertained. Finally, a comparison with the axisymmetric flow analog is presented.

14 CFR 170.13 - Airport Traffic Control Tower (ATCT) establishment criteria.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Airport Traffic Control Tower (ATCT... AIR TRAFFIC CONTROL SERVICES AND NAVIGATIONAL FACILITIES Airport Traffic Control Towers § 170.13 Airport Traffic Control Tower (ATCT) establishment criteria. (a) The following criteria along with general...

Evaluation of Ohio work zone speed zones process.

DOT National Transportation Integrated Search

2014-06-01

This report describes the methodology and results of analyses performed to determine the effectiveness of Ohio Department of Transportation processes for establishing work zone speed zones. Researchers observed motorists speed choice upstream of a...

Supporting the Future Air Traffic Control Projection Process

NASA Technical Reports Server (NTRS)

Davison, Hayley J.; Hansman, R. John, Jr.

2002-01-01

In air traffic control, projecting what the air traffic situation will be over the next 30 seconds to 30 minutes is a key process in identifying conflicts that may arise so that evasive action can be taken upon discovery of these conflicts. A series of field visits in the Boston and New York terminal radar approach control (TRACON) facilities and in the oceanic air traffic control facilities in New York and Reykjavik, Iceland were conducted to investigate the projection process in two different ATC domains. The results from the site visits suggest that two types of projection are currently used in ATC tasks, depending on the type of separation minima and/or traffic restriction and information display used by the controller. As technologies improve and procedures change, care should be taken by designers to support projection through displays, automation, and procedures. It is critical to prevent time/space mismatches between interfaces and restrictions. Existing structure in traffic dynamics could be utilized to provide controllers with useful behavioral models on which to build projections. Subtle structure that the controllers are unable to internalize could be incorporated into an ATC projection aid.

Pedestrian friendly traffic signal control : final research report.

DOT National Transportation Integrated Search

2016-01-01

This project continues research aimed at real-time detection and use of pedestrian : traffic flow information to enhance adaptive traffic signal control in urban areas : where pedestrian traffic is substantial and must be given appropriate attention ...

An efficient method to detect periodic behavior in botnet traffic by analyzing control plane traffic

PubMed Central

AsSadhan, Basil; Moura, José M.F.

2013-01-01

Botnets are large networks of bots (compromised machines) that are under the control of a small number of bot masters. They pose a significant threat to Internet’s communications and applications. A botnet relies on command and control (C2) communications channels traffic between its members for its attack execution. C2 traffic occurs prior to any attack; hence, the detection of botnet’s C2 traffic enables the detection of members of the botnet before any real harm happens. We analyze C2 traffic and find that it exhibits a periodic behavior. This is due to the pre-programmed behavior of bots that check for updates to download them every T seconds. We exploit this periodic behavior to detect C2 traffic. The detection involves evaluating the periodogram of the monitored traffic. Then applying Walker’s large sample test to the periodogram’s maximum ordinate in order to determine if it is due to a periodic component or not. If the periodogram of the monitored traffic contains a periodic component, then it is highly likely that it is due to a bot’s C2 traffic. The test looks only at aggregate control plane traffic behavior, which makes it more scalable than techniques that involve deep packet inspection (DPI) or tracking the communication flows of different hosts. We apply the test to two types of botnet, tinyP2P and IRC that are generated by SLINGbot. We verify the periodic behavior of their C2 traffic and compare it to the results we get on real traffic that is obtained from a secured enterprise network. We further study the characteristics of the test in the presence of injected HTTP background traffic and the effect of the duty cycle on the periodic behavior. PMID:25685512

Countermeasures that work : seventh edition : traffic tech.

DOT National Transportation Integrated Search

2013-04-01

The National Highway Traffic Safety Administration has published the seventh edition of Countermeasures That Work. The guide is a basic reference to assist State Highway Safety Offices (SHSOs) in selecting effective, evidence-based countermeasures fo...

A computerized traffic control algorithm to determine optimal traffic signal settings. Ph.D. Thesis - Toledo Univ.

NASA Technical Reports Server (NTRS)

Seldner, K.

1977-01-01

An algorithm was developed to optimally control the traffic signals at each intersection using a discrete time traffic model applicable to heavy or peak traffic. Off line optimization procedures were applied to compute the cycle splits required to minimize the lengths of the vehicle queues and delay at each intersection. The method was applied to an extensive traffic network in Toledo, Ohio. Results obtained with the derived optimal settings are compared with the control settings presently in use.

Control of Networked Traffic Flow Distribution - A Stochastic Distribution System Perspective

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

Wang, Hong; Aziz, H M Abdul; Young, Stan

Networked traffic flow is a common scenario for urban transportation, where the distribution of vehicle queues either at controlled intersections or highway segments reflect the smoothness of the traffic flow in the network. At signalized intersections, the traffic queues are controlled by traffic signal control settings and effective traffic lights control would realize both smooth traffic flow and minimize fuel consumption. Funded by the Energy Efficient Mobility Systems (EEMS) program of the Vehicle Technologies Office of the US Department of Energy, we performed a preliminary investigation on the modelling and control framework in context of urban network of signalized intersections.more » In specific, we developed a recursive input-output traffic queueing models. The queue formation can be modeled as a stochastic process where the number of vehicles entering each intersection is a random number. Further, we proposed a preliminary B-Spline stochastic model for a one-way single-lane corridor traffic system based on theory of stochastic distribution control.. It has been shown that the developed stochastic model would provide the optimal probability density function (PDF) of the traffic queueing length as a dynamic function of the traffic signal setting parameters. Based upon such a stochastic distribution model, we have proposed a preliminary closed loop framework on stochastic distribution control for the traffic queueing system to make the traffic queueing length PDF follow a target PDF that potentially realizes the smooth traffic flow distribution in a concerned corridor.« less

A temperature control design for a tapered element oscillating microbalance sensing surface

NASA Technical Reports Server (NTRS)

1982-01-01

A design study is presented which shows that a tapered element oscillating microbalance can be adapted for temperature control under space application by mating with multistage thermoelectric coolers in such a way that an integral structure evolves. The control of the temperature of the sensing surface can be achieved in a number of ways. An indirect method which uses a measurement of the absorbed power is recommended. The design goals can be met if a relaxation of the power requirement can be considered.

Countermeasures that work : eighth edition : traffic tech.

DOT National Transportation Integrated Search

2016-01-01

The National Highway Traffic Safety Administration has published its eighth edition of Countermeasures That Work. The guide is a basic reference to assist State Highway Safety Offices (SHSOs) and other professionals interested in highway safety in se...

Neck postures in air traffic controllers with and without neck/shoulder disorders.

PubMed

Arvidsson, Inger; Hansson, Gert-Ake; Mathiassen, Svend Erik; Skerfving, Staffan

2008-03-01

Prolonged computer work with an extended neck is commonly believed to be associated with an increased risk of neck-shoulder disorders. The aim of this study was to compare neck postures during computer work between female cases with neck-shoulder disorders, and healthy referents. Based on physical examinations, 13 cases and 11 referents were selected among 70 female air traffic controllers with the same computer-based work tasks and identical workstations. Postures and movements were measured by inclinometers, placed on the forehead and upper back (C7/Th1) during authentic air traffic control. A recently developed method was applied to assess flexion/extension in the neck, calculated as the difference between head and upper back flexion/extension. cases and referents did not differ significantly in neck posture (median neck flexion/extension: -10 degrees vs. -9 degrees ; p=0.9). Hence, the belief that neck extension posture is associated with neck-shoulder disorders in computer work is not supported by the present data.

A Sarsa(λ)-based control model for real-time traffic light coordination.

PubMed

Zhou, Xiaoke; Zhu, Fei; Liu, Quan; Fu, Yuchen; Huang, Wei

2014-01-01

Traffic problems often occur due to the traffic demands by the outnumbered vehicles on road. Maximizing traffic flow and minimizing the average waiting time are the goals of intelligent traffic control. Each junction wants to get larger traffic flow. During the course, junctions form a policy of coordination as well as constraints for adjacent junctions to maximize their own interests. A good traffic signal timing policy is helpful to solve the problem. However, as there are so many factors that can affect the traffic control model, it is difficult to find the optimal solution. The disability of traffic light controllers to learn from past experiences caused them to be unable to adaptively fit dynamic changes of traffic flow. Considering dynamic characteristics of the actual traffic environment, reinforcement learning algorithm based traffic control approach can be applied to get optimal scheduling policy. The proposed Sarsa(λ)-based real-time traffic control optimization model can maintain the traffic signal timing policy more effectively. The Sarsa(λ)-based model gains traffic cost of the vehicle, which considers delay time, the number of waiting vehicles, and the integrated saturation from its experiences to learn and determine the optimal actions. The experiment results show an inspiring improvement in traffic control, indicating the proposed model is capable of facilitating real-time dynamic traffic control.

A Sarsa(λ)-Based Control Model for Real-Time Traffic Light Coordination

PubMed Central

Zhu, Fei; Liu, Quan; Fu, Yuchen; Huang, Wei

2014-01-01

Traffic problems often occur due to the traffic demands by the outnumbered vehicles on road. Maximizing traffic flow and minimizing the average waiting time are the goals of intelligent traffic control. Each junction wants to get larger traffic flow. During the course, junctions form a policy of coordination as well as constraints for adjacent junctions to maximize their own interests. A good traffic signal timing policy is helpful to solve the problem. However, as there are so many factors that can affect the traffic control model, it is difficult to find the optimal solution. The disability of traffic light controllers to learn from past experiences caused them to be unable to adaptively fit dynamic changes of traffic flow. Considering dynamic characteristics of the actual traffic environment, reinforcement learning algorithm based traffic control approach can be applied to get optimal scheduling policy. The proposed Sarsa(λ)-based real-time traffic control optimization model can maintain the traffic signal timing policy more effectively. The Sarsa(λ)-based model gains traffic cost of the vehicle, which considers delay time, the number of waiting vehicles, and the integrated saturation from its experiences to learn and determine the optimal actions. The experiment results show an inspiring improvement in traffic control, indicating the proposed model is capable of facilitating real-time dynamic traffic control. PMID:24592183

Fatal accidents in nighttime vs. daytime highway construction work zones.

PubMed

Arditi, David; Lee, Dong-Eun; Polat, Gul

2007-01-01

Awareness about worker safety in nighttime construction has been a major concern because it is believed that nighttime construction creates hazardous work conditions. However, only a few studies provide valuable comparative information about accident characteristics of nighttime and daytime highway construction activities. This study investigates fatal accidents that occurred in Illinois highway work zones in the period 1996-2001 in order to determine the safety differences between nighttime and daytime highway construction. The lighting and weather conditions were included into the study as control parameters to see their effects on the frequency of fatal accidents occurring in work zones. According to this study, there is evidence that nighttime construction is more hazardous than daytime construction. The inclusion of a weather parameter into the analysis has limited effect on this finding. The study justifies establishing an efficient work zone accident reporting system and taking all necessary measures to enhance safety in nighttime work zones.

Motorist compliance with standard traffic control devices.

DOT National Transportation Integrated Search

1989-04-01

This report describes a study of motorist compliance with standard traffic control : devices. The research included a comprehensive review of past studies, contacts : with traffic, law enforcement, and department of motor vehicles personnel, and an :...

A Vision of the Future Air Traffic Control System

NASA Technical Reports Server (NTRS)

Erzberger, Heinz

2000-01-01

The air transportation system is on the verge of gridlock, with delays and cancelled flights this summer reaching all time highs. As demand for air transportation continues to increase, the capacity needed to accommodate the growth in traffic is falling farther and farther behind. Moreover, it has become increasingly apparent that the present system cannot be scaled up to provide the capacity increases needed to meet demand over the next 25 years. NASA, working with the Federal Aviation Administration and industry, is pursuing a major research program to develop air traffic management technologies that have the ultimate goal of doubling capacity while increasing safety and efficiency. This seminar will describe how the current system operates, what its limitations are and why a revolutionary "shift in paradigm" is needed to overcome fundamental limitations in capacity and safety. For the near term, NASA has developed a portfolio of software tools for air traffic controllers, called the Center-TRACON Automation System (CTAS), that provides modest gains in capacity and efficiency while staying within the current paradigm. The outline of a concept for the long term, with a deployment date of 2015 at the earliest, has recently been formulated and presented by NASA to a select group of industry and government stakeholders. Automated decision making software, combined with an Internet in the sky that enables sharing of information and distributes control between the cockpit and the ground, is key to this concept. However, its most revolutionary feature is a fundamental change in the roles and responsibilities assigned to air traffic controllers.

Evaluation of work zone speed limits : an objective and subjective analysis of work zones in Missouri.

DOT National Transportation Integrated Search

2011-02-01

This study objectively and subjectively examined speed characteristics and driver compliance with the posted speed limit : in Missouri work zones. The objective evaluation collected vehicle speeds from four work zones with different : configurations ...

Air traffic control specialist performance measurement database.

DOT National Transportation Integrated Search

1999-06-01

The Air Traffic Control Specialist (ATCS) Performance Measurement Database is a compilation of performance measures and : measurement techniques that researchers have used. It may be applicable to other human factor research related to air traffic co...

Congestion control strategy on complex network with privilege traffic

NASA Astrophysics Data System (ADS)

Li, Shi-Bao; He, Ya; Liu, Jian-Hang; Zhang, Zhi-Gang; Huang, Jun-Wei

The congestion control of traffic is one of the most important studies in complex networks. In the previous congestion algorithms, all the network traffic is assumed to have the same priority, and the privilege of traffic is ignored. In this paper, a privilege and common traffic congestion control routing strategy (PCR) based on the different priority of traffic is proposed, which can be devised to cope with the different traffic congestion situations. We introduce the concept of privilege traffic in traffic dynamics for the first time and construct a new traffic model which taking into account requirements with different priorities. Besides, a new factor Ui is introduced by the theoretical derivation to characterize the interaction between different traffic routing selection, furthermore, Ui is related to the network throughput. Since the joint optimization among different kinds of traffic is accomplished by PCR, the maximum value of Ui can be significantly reduced and the network performance can be improved observably. The simulation results indicate that the network throughput with PCR has a better performance than the other strategies. Moreover, the network capacity is improved by 25% at least. Additionally, the network throughput is also influenced by privilege traffic number and traffic priority.

Improving work zone safety through speed management.

DOT National Transportation Integrated Search

2013-06-01

Safety hazards are increased in highway work zones as the dynamics of a work zone introduce a constantly changing : environment with varying levels of risk. Excessive speeding through work and maintenance zones is a common occurrence : which elevates...

Do Stem Taper Microgrooves Influence Taper Corrosion in Total Hip Arthroplasty? A Matched Cohort Retrieval Study.

PubMed

Arnholt, Christina M; MacDonald, Daniel W; Underwood, Richard J; Guyer, Eric P; Rimnac, Clare M; Kurtz, Steven M; Mont, Michael A; Klein, Gregg R; Lee, Gwo-Chin; Chen, Antonia F; Hamlin, Brian R; Cates, Harold E; Malkani, Arthur L; Kraay, Matthew J

2017-04-01

Previous studies identified imprinting of the stem morphology onto the interior head bore, leading researchers to hypothesize an influence of taper topography on mechanically assisted crevice corrosion. The purpose of this study was to analyze whether microgrooved stem tapers result in greater fretting corrosion damage than smooth stem tapers. A matched cohort of 120 retrieved head-stem pairs from metal-on-polyethylene bearings was created controlling for implantation time, flexural rigidity, apparent length of engagement, and head size. There were 2 groups of 60 heads each, mated with either smooth or microgrooved stem tapers. A high-precision roundness machine was used to measure and categorize the surface morphology. Fretting corrosion damage at the head-neck junction was characterized using the Higgs-Goldberg scoring method. Fourteen of the most damaged heads were analyzed for the maximum depth of material loss and focused ion beam cross-sectioned to view oxide and base metal. Fretting corrosion damage was not different between the 2 cohorts at the femoral head (P = .14, Mann-Whitney) or stem tapers (P = .35). There was no difference in the maximum depths of material loss between the cohorts (P = .71). Cross-sectioning revealed contact damage, signs of micro-motion, and chromium-rich oxide layers in both cohorts. Microgroove imprinting did not appear to have a different effect on the fretting corrosion behavior. The results of this matched cohort retrieval study do not support the hypothesis that taper surfaces with microgrooved stems exhibit increased in vivo fretting corrosion damage or material release. Copyright © 2016 Elsevier Inc. All rights reserved.

Air Traffic ControL : FAA Order 7110.65K

DOT National Transportation Integrated Search

1997-07-17

This order prescribes air traffic control procedures and phraseology for use by : personnel providing air traffic control services. Controllers are required to : be familiar with the provisions of this order that pertain to their operational : respon...

Traffic control device conspicuity.

DOT National Transportation Integrated Search

2013-08-01

The conspicuity of a traffic control device (TCD) is defined as the probability that the device will be noticed. However, there is no agreed-upon measure of what constitutes being noticed. Various measures have been suggested, including eye fixations...

Modal demultiplexing properties of tapered and nanostructured optical fibers for in vivo optogenetic control of neural activity.

PubMed

Pisanello, Marco; Della Patria, Andrea; Sileo, Leonardo; Sabatini, Bernardo L; De Vittorio, Massimo; Pisanello, Ferruccio

2015-10-01

Optogenetic approaches to manipulate neural activity have revolutionized the ability of neuroscientists to uncover the functional connectivity underlying brain function. At the same time, the increasing complexity of in vivo optogenetic experiments has increased the demand for new techniques to precisely deliver light into the brain, in particular to illuminate selected portions of the neural tissue. Tapered and nanopatterned gold-coated optical fibers were recently proposed as minimally invasive multipoint light delivery devices, allowing for site-selective optogenetic stimulation in the mammalian brain [Pisanello , Neuron82, 1245 (2014)]. Here we demonstrate that the working principle behind these devices is based on the mode-selective photonic properties of the fiber taper. Using analytical and ray tracing models we model the finite conductance of the metal coating, and show that single or multiple optical windows located at specific taper sections can outcouple only specific subsets of guided modes injected into the fiber.

Planes, Politics and Oral Proficiency: Testing International Air Traffic Controllers

ERIC Educational Resources Information Center

Moder, Carol Lynn; Halleck, Gene B.

2009-01-01

This study investigates the variation in oral proficiency demonstrated by 14 Air Traffic Controllers across two types of testing tasks: work-related radio telephony-based tasks and non-specific English tasks on aviation topics. Their performance was compared statistically in terms of level ratings on the International Civil Aviation Organization…

Methods and measurements in real-time air traffic control system simulation.

DOT National Transportation Integrated Search

1983-04-01

The major purpose of this work was to asses dynamic simulation of air traffic control systems as a technique for evaluating such systems in a statistically sound and objective manner. A large set of customarily used measures based on the system missi...

Effects of Automation Types on Air Traffic Controller Situation Awareness and Performance

NASA Technical Reports Server (NTRS)

Sethumadhavan, A.

2009-01-01

The Joint Planning and Development Office has proposed the introduction of automated systems to help air traffic controllers handle the increasing volume of air traffic in the next two decades (JPDO, 2007). Because fully automated systems leave operators out of the decision-making loop (e.g., Billings, 1991), it is important to determine the right level and type of automation that will keep air traffic controllers in the loop. This study examined the differences in the situation awareness (SA) and collision detection performance of individuals when they worked with information acquisition, information analysis, decision and action selection and action implementation automation to control air traffic (Parasuraman, Sheridan, & Wickens, 2000). When the automation was unreliable, the time taken to detect an upcoming collision was significantly longer for all the automation types compared with the information acquisition automation. This poor performance following automation failure was mediated by SA, with lower SA yielding poor performance. Thus, the costs associated with automation failure are greater when automation is applied to higher order stages of information processing. Results have practical implications for automation design and development of SA training programs.

An evaluation of factors influencing pore pressure in accretionary complexes: Implications for taper angle and wedge mechanics

USGS Publications Warehouse

Saffer, D.M.; Bekins, B.A.

2006-01-01

At many subduction zones, accretionary complexes form as sediment is off-scraped from the subducting plate. Mechanical models that treat accretionary complexes as critically tapered wedges of sediment demonstrate that pore pressure controls their taper angle by modifying basal and internal shear strength. Here, we combine a numerical model of groundwater flow with critical taper theory to quantify the effects of sediment and de??collement permeability, sediment thickness, sediment partitioning between accretion and underthrusting, and plate convergence rate on steady state pore pressure. Our results show that pore pressure in accretionary wedges can be viewed as a dynamically maintained response to factors which drive pore pressure (source terms) and those that limit flow (permeability and drainage path length). We find that sediment permeability and incoming sediment thickness are the most important factors, whereas fault permeability and the partitioning of sediment have a small effect. For our base case model scenario, as sediment permeability is increased, pore pressure decreases from near-lithostatic to hydrostatic values and allows stable taper angles to increase from ??? 2.5?? to 8??-12.5??. With increased sediment thickness in our models (from 100 to 8000 m), increased pore pressure drives a decrease in stable taper angle from 8.4??-12.5?? to 15?? to <4??) with increased sediment thickness (from <1 to 7 km). One key implication is that hydrologic properties may strongly influence the strength of the crust in a wide range of geologic settings. Copyright 2006 by the American Geophysical Union.

Human performance interfaces in air traffic control.

PubMed

Chang, Yu-Hern; Yeh, Chung-Hsing

2010-01-01

This paper examines how human performance factors in air traffic control (ATC) affect each other through their mutual interactions. The paper extends the conceptual SHEL model of ergonomics to describe the ATC system as human performance interfaces in which the air traffic controllers interact with other human performance factors including other controllers, software, hardware, environment, and organisation. New research hypotheses about the relationships between human performance interfaces of the system are developed and tested on data collected from air traffic controllers, using structural equation modelling. The research result suggests that organisation influences play a more significant role than individual differences or peer influences on how the controllers interact with the software, hardware, and environment of the ATC system. There are mutual influences between the controller-software, controller-hardware, controller-environment, and controller-organisation interfaces of the ATC system, with the exception of the controller-controller interface. Research findings of this study provide practical insights in managing human performance interfaces of the ATC system in the face of internal or external change, particularly in understanding its possible consequences in relation to the interactions between human performance factors.

Assessment of Air Traffic Controller Acceptability of Aircrew Route Change Requests

NASA Technical Reports Server (NTRS)

Idris, Husni; Enea, Gabriele; Burke, Kelly; Wing, David

2017-01-01

NASA developed the traffic aware strategic aircrew requests concept for a cockpit automation that identifies route improvements and advises the aircrew to request the change from the air traffic controller. In order to increase the chance of air traffic control approval, the automation ensures that the route is clear of known traffic, weather, and airspace restrictions. Hence the technology is anticipated to provide benefits in areas such as flight efficiency, flight schedule compliance, passenger comfort, and pilot and controller workload. In support of a field trial of a prototype of the technology, observations were conducted at the Atlanta and Jacksonville air traffic control centers to identify the main factors that affect the acceptability of aircrew requests by air traffic controllers. Observers shadowed air traffic controllers as the test flight pilot made pre-scripted requests to invoke acceptability issues and then they interviewed voluntarily fifty controllers with experience ranging from one to thirty-five years. The most common reason for rejecting requests is conflicting with traffic followed by violating air traffic procedures, increasing sector workload, and conflicting with major arrival and departure flows and flow restrictions. Quantitative parameters such as the distance that a route should maintain from sector boundaries and special use airspace were identified and recommended for inclusion in the automation.

Trainer Interventions as Instructional Strategies in Air Traffic Control Training

ERIC Educational Resources Information Center

Koskela, Inka; Palukka, Hannele

2011-01-01

Purpose: This paper aims to identify methods of guidance and supervision used in air traffic control training. It also aims to show how these methods facilitate trainee participation in core work activities. Design/methodology/approach: The paper applies the tools of conversation analysis and ethnomethodology to explore the ways in which trainers…

Evaluation of Intersection Traffic Control Measures through Simulation

NASA Astrophysics Data System (ADS)

Asaithambi, Gowri; Sivanandan, R.

2015-12-01

Modeling traffic flow is stochastic in nature due to randomness in variables such as vehicle arrivals and speeds. Due to this and due to complex vehicular interactions and their manoeuvres, it is extremely difficult to model the traffic flow through analytical methods. To study this type of complex traffic system and vehicle interactions, simulation is considered as an effective tool. Application of homogeneous traffic models to heterogeneous traffic may not be able to capture the complex manoeuvres and interactions in such flows. Hence, a microscopic simulation model for heterogeneous traffic is developed using object oriented concepts. This simulation model acts as a tool for evaluating various control measures at signalized intersections. The present study focuses on the evaluation of Right Turn Lane (RTL) and Channelised Left Turn Lane (CLTL). A sensitivity analysis was performed to evaluate RTL and CLTL by varying the approach volumes, turn proportions and turn lane lengths. RTL is found to be advantageous only up to certain approach volumes and right-turn proportions, beyond which it is counter-productive. CLTL is found to be advantageous for lower approach volumes for all turn proportions, signifying the benefits of CLTL. It is counter-productive for higher approach volume and lower turn proportions. This study pinpoints the break-even points for various scenarios. The developed simulation model can be used as an appropriate intersection lane control tool for enhancing the efficiency of flow at intersections. This model can also be employed for scenario analysis and can be valuable to field traffic engineers in implementing vehicle-type based and lane-based traffic control measures.

Do Stem Taper Microgrooves Influence Taper Corrosion in Total Hip Arthroplasty? A Matched Cohort Retrieval Study

PubMed Central

Arnholt, Christina M.; MacDonald, Daniel W.; Underwood, Richard; Guyer, Eric P.; Rimnac, Clare M.; Kurtz, Steven M.; Mont, Michael A.; Klein, Gregg; Lee, Gwo-Chin; Chen, Antonia F.; Hamlin, Brian; Cates, Harold; Malkani, Arthur; Kraay, Matthew

2017-01-01

Background Previous studies identified imprinting of the stem morphology onto the interior head bore, leading researchers to hypothesize an influence of taper topography on mechanically assisted crevice corrosion (MACC). The purpose of this study was to analyze whether micro-grooved stem tapers result in greater fretting corrosion damage than smooth stem tapers. Methods A matched cohort of 120 retrieved head-stem pairs from metal-on-polyethylene bearings was created controlling for implantation time, flexural rigidity, apparent length of engagement, and head size. There were two groups of 60 heads each, mated with either smooth or micro-grooved stem tapers. A high precision roundness machine was used to measure and categorize the surface morphology. Fretting corrosion damage at the head/neck junction was characterized using the Higgs-Goldberg scoring method. Fourteen of the most damaged heads, were analyzed for the maximum depth of material loss and focused ion beam (FIB) cross-sectioned to view oxide and base metal. Results Fretting corrosion damage was not different between the two cohorts at the femoral head (p = 0.14, Mann Whitney) or stem tapers (p = 0.35). There was no difference in the maximum depths of material loss between the cohorts (p = 0.71). Cross sectioning revealed contact damage, signs of micro-motion, and chromium rich oxide layers in both cohorts. Micro-groove imprinting did not appear to have a different effect on the fretting corrosion behavior. Conclusion The results of this matched cohort retrieval study do not support the hypothesis that taper surfaces with micro-grooved stems exhibit increased in vivo fretting corrosion damage or material release. PMID:28111124

A hierarchical framework for air traffic control

NASA Astrophysics Data System (ADS)

Roy, Kaushik

Air travel in recent years has been plagued by record delays, with over $8 billion in direct operating costs being attributed to 100 million flight delay minutes in 2007. Major contributing factors to delay include weather, congestion, and aging infrastructure; the Next Generation Air Transportation System (NextGen) aims to alleviate these delays through an upgrade of the air traffic control system. Changes to large-scale networked systems such as air traffic control are complicated by the need for coordinated solutions over disparate temporal and spatial scales. Individual air traffic controllers must ensure aircraft maintain safe separation locally with a time horizon of seconds to minutes, whereas regional plans are formulated to efficiently route flows of aircraft around weather and congestion on the order of every hour. More efficient control algorithms that provide a coordinated solution are required to safely handle a larger number of aircraft in a fixed amount of airspace. Improved estimation algorithms are also needed to provide accurate aircraft state information and situational awareness for human controllers. A hierarchical framework is developed to simultaneously solve the sometimes conflicting goals of regional efficiency and local safety. Careful attention is given in defining the interactions between the layers of this hierarchy. In this way, solutions to individual air traffic problems can be targeted and implemented as needed. First, the regional traffic flow management problem is posed as an optimization problem and shown to be NP-Hard. Approximation methods based on aggregate flow models are developed to enable real-time implementation of algorithms that reduce the impact of congestion and adverse weather. Second, the local trajectory design problem is solved using a novel slot-based sector model. This model is used to analyze sector capacity under varying traffic patterns, providing a more comprehensive understanding of how increased automation

Analysis of passenger-car crash injury severity in different work zone configurations.

PubMed

Osman, Mohamed; Paleti, Rajesh; Mishra, Sabyasachee

2018-02-01

Work zone safety remains a priority to the Federal Highway Administration, State Highway Departments, highway engineers, and the traveling public. Work zones create a hospitable environment for crashes; an issue that gained tremendous share of attention in recent years. Therefore, every effort should be sought out to reduce the injury severity of crashes in work zones. In this paper we attempt to investigate factors contributing to the injury severity of passenger-car crashes in different work zone configurations. Considering the discrete ordinal nature of injury severity categories, a Mixed Generalized Ordered Response Probit (MGORP) modeling framework was developed. The model estimation was undertaken by compiling a database consisting of 10 years of crashes that involved at least one passenger car, and occurred in a work zone. Revealing the underlying factors contributing to injury severity levels for different work zone configurations will allow for distinguishing mitigation methods for higher severity outcomes that best suit each of the depicted work zone layouts. This can be accomplished through the implementation of specific safety measures based on the specific configuration of a work zone as a potential crash location. Elasticity analysis suggests that partial control of access, roadways classified as rural, crashes during evening times, crashes during weekends, and curved roadways are key factors that increase the likelihood of severe outcomes. Also, the effects of several covariates were found to vary across the different work zone configurations. Copyright © 2017 Elsevier Ltd. All rights reserved.

An automated testing tool for traffic signal controller functionalities.

DOT National Transportation Integrated Search

2010-03-01

The purpose of this project was to develop an automated tool that facilitates testing of traffic controller functionality using controller interface device (CID) technology. Benefits of such automated testers to traffic engineers include reduced test...

Analysis of traffic signal work backlog in Louisiana : technical assistance report.

DOT National Transportation Integrated Search

1995-07-01

A review of Traffic Services' traffic signal work records reveals the source of the backlog. During the 1980's, the department experienced personnel cutbacks and hiring freezes that caused the number of field personnel to drop from 40 to 24. Simultan...

Traffic Generator (TrafficGen) Version 1.4.2: Users Guide

DTIC Science & Technology

2016-06-01

events, the user has to enter them manually . We will research and implement a way to better define and organize the multicast addresses so they can be...the network with Transmission Control Protocol and User Datagram Protocol Internet Protocol traffic. Each node generating network traffic in an...TrafficGen Graphical User Interface (GUI) 3 3.1 Anatomy of the User Interface 3 3.2 Scenario Configuration and MGEN Files 4 4. Working with

Magnitude and outcomes of road traffic accidents at Hospitals in Wolaita Zone, SNNPR, Ethiopia.

PubMed

Hailemichael, Feleke; Suleiman, Mohammed; Pauolos, Wondimagegn

2015-04-09

A Road traffic accident is an incident on a way or street open to public traffic, resulting in one or more persons being killed or injured, and involving at least one moving vehicle. The aim of this study is to assess magnitude and outcome of road traffic accidents among trauma victims at hospitals in Wolaita zone. A cross sectional hospital based study design using retrospective chart review was conducted from March 5th to March 25th, 2014. Simple random sampling technique was applied to identify sample population. The data was entered in to Epi info version 3.5.1 and transferred to SPSS version 16 for further analysis. A total of 384 trauma victims were incorporated in the study of which 240 (62.5%) were due to road traffic accidents. The majority of patients were male 298 (77.6%) and most commonly aged between 20-29 (35.42%). The principal outcome of injury was more commonly lower extremity (182 patients, 47.4%), compared to upper extremity (126 patients, 32.8%). Of all trauma patient presenting to hospitals (62.5%) are the result of road traffic accident. Hence, the provision of tailored messages to all members of the community regarding knowledge and practices of road safety measures like appropriate use of pavements by pedestrians and avoiding risky driving behaviors. Besides this make use of compulsory motorcycle helmets would appear to be a very important intervention.

Evaluation of New Jersey Route 18 OPAC/MIST traffic-control system

DOT National Transportation Integrated Search

1997-01-01

Conventional traffic-control strategies have limitations in handling unanticipated traffic demands. An adaptive traffic-signal control is expected to mitigate this problem and improve overall system performance. Furthermore, with the increasing needs...

Effect of changing driving conditions on driver behavior towards design of a safe and efficient traffic system.

DOT National Transportation Integrated Search

2013-12-01

This simulation-based study explores the effects of different work zone configurations, varying distances : between traffic signs, traffic density and individual differences on drivers behavior. Conventional Lane : Merge (CLM) and Joint Lane Merge...

Broadcast control of air traffic

NASA Technical Reports Server (NTRS)

Litchford, G. B.

1972-01-01

The development of a system of broadcast control for improved flight safety and air traffic control is discussed. The system provides a balance of equality between improved cockpit guidance and control capability and ground control in order to provide the pilot with a greater degree of participation. The manner in which the system is operated and the equipment required for safe operation are examined.

Enhancing sensitivity of biconical tapered fiber sensors with multiple passes through the taper

NASA Astrophysics Data System (ADS)

Cohoon, Gregory; Boyter, Chris; Errico, Michael; Vandervoort, Kurt; Salik, Ertan

2010-03-01

A single biconical fiber taper is a simple and low-cost yet powerful sensor. With a distinct strength in refractive index (RI) sensing, biconical tapered fiber sensors can find their place in handheld sensor platforms, especially as biosensors that are greatly needed in health care, environmental protection, food safety, and biodefense. We report doubling of sensitivity for these sensors with two passes through the tapered region, which becomes possible through the use of sensitive and high-dynamic-range photodetectors. In a proof-of-principle experiment, we measured transmission through the taper when it was immersed in isopropyl alcohol-water mixtures of varying concentrations, in which a thin gold layer at the tip of the fiber acted as a mirror enabling two passes through the tapered region. This improved the sensitivity from 0.43 dB/vol % in the single-pass case to 0.78 dB/vol % with two passes through the taper. The refractive index detection limit was estimated to be ~1.2×10-5 RI units (RIU) and ~0.6×10-5 RIU in the single- and double-pass schemes, respectively. We predict that further enhancement of sensitivity may be achieved with a higher number of passes through the taper.

Work zone performance measures pilot test.

DOT National Transportation Integrated Search

2011-04-01

Currently, a well-defined and validated set of metrics to use in monitoring work zone performance do not : exist. This pilot test was conducted to assist state DOTs in identifying what work zone performance : measures can and should be targeted, what...

Work Zone Intrusion Report Interface Design

DOT National Transportation Integrated Search

2018-02-02

While necessary for roadways, work zones present a safety risk to crew. Half of road workers deaths between 2005 and 2010 were due to collisions with motorists intruding on the work zone. Therefore, addressing intrusions is an important step for ensu...

Thulium fiber laser lithotripsy using tapered fibers.

PubMed

Blackmon, Richard L; Irby, Pierce B; Fried, Nathaniel M

2010-01-01

The Thulium fiber laser has recently been tested as a potential alternative to the Holmium:YAG laser for lithotripsy. This study explores use of a short taper for expanding the Thulium fiber laser beam at the distal tip of a small-core fiber. Thulium fiber laser radiation with a wavelength of 1,908 nm, 10 Hz pulse rate, 70 mJ pulse energy, and 1-millisecond pulse duration was delivered through a 2-m-length fiber with 150-microm-core-input-end, 300-microm-core-output-end, and 5-mm-length taper, in contact with human uric acid (UA) and calcium oxalate monohydrate (COM) stones, ex vivo (n = 10 each). Stone mass loss, stone crater depths, fiber transmission losses, fiber burn-back, irrigation rates, and deflection through a flexible ureteroscope were measured for the tapered fiber and compared with conventional fibers. After delivery of 1,800 pulses through the tapered fiber, mass loss measured 12.7+/-2.6 mg for UA and 7.2+/-0.8 mg COM stones, comparable to conventional 100-microm-core fibers (12.6+/-2.5 mg for UA and 6.8+/-1.7 mg for COM stones). No transmission losses or burn-back occurred for the tapered fiber after 36,000 pulses, while a conventional 150-microm fiber experienced significant tip degradation after only 1,800 pulses. High irrigation rates were measured with the tapered fiber inserted through the working port of a flexible ureteroscope without hindering its deflection, mimicking that of a conventional 150 microm fiber. The short tapered distal fiber tip allows expansion of the laser beam, resulting in decreased fiber tip damage compared to conventional small-core fibers, without compromising fiber bending, stone vaporization efficiency, or irrigation rates.

Performance evaluation of traffic sensing and control devices.

DOT National Transportation Integrated Search

2011-01-01

High quality vehicle detection is essential to properly operate actuated phases at traffic signals and to facilitate effective : management of technician and engineering resources. INDOT operates over 2600 traffic signal controllers, approximately 20...

Speeds in school zones.

DOT National Transportation Integrated Search

2009-02-01

School speed zones are frequently requested traffic controls for school areas, based on the common belief : that if the transportation agency would only install a reduced speed limit, then drivers would no longer : speed through the area. This resear...

Quality of Life, Sleep, and Health of Air Traffic Controllers With Rapid Counterclockwise Shift Rotation.

PubMed

Sonati, Jaqueline Girnos; De Martino, Milva Maria Figueiredo; Vilarta, Roberto; da Silva Maciel, Érika; Sonati, Renato José Ferreira; Paduan, Paulo Cézar

2016-08-01

Rotating shiftwork is common for air traffic controllers and usually causes sleep deprivation, biological adaptations, and life changes for these workers. This study assessed quality of life, the sleep, and the health of 30 air traffic controllers employed at an international airport in Brazil. The objective was to identify health and quality of life concerns of these professionals. The results identified physical inactivity, overweight, excess body fat, low scores for physical and social relationships, and sleep deprivation for workers in all four workshifts. In conclusion, these workers are at risk for chronic non-transmittable diseases and compromised work performance, suggesting the need for more rest time before working nightshifts and work environments that stimulate physical activity and healthy diets. © 2016 The Author(s).

Adiabatic tapered optical fiber fabrication in two step etching

NASA Astrophysics Data System (ADS)

Chenari, Z.; Latifi, H.; Ghamari, S.; Hashemi, R. S.; Doroodmand, F.

2016-01-01

A two-step etching method using HF acid and Buffered HF is proposed to fabricate adiabatic biconical optical fiber tapers. Due to the fact that the etching rate in second step is almost 3 times slower than the previous droplet etching method, terminating the fabrication process is controllable enough to achieve a desirable fiber diameter. By monitoring transmitted spectrum, final diameter and adiabaticity of tapers are deduced. Tapers with losses about 0.3 dB in air and 4.2 dB in water are produced. The biconical fiber taper fabricated using this method is used to excite whispering gallery modes (WGMs) on a microsphere surface in an aquatic environment. So that they are suitable to be used in applications like WGM biosensors.

Determination of traffic intensity from camera images using image processing and pattern recognition techniques

NASA Astrophysics Data System (ADS)

Mehrübeoğlu, Mehrübe; McLauchlan, Lifford

2006-02-01

The goal of this project was to detect the intensity of traffic on a road at different times of the day during daytime. Although the work presented utilized images from a section of a highway, the results of this project are intended for making decisions on the type of intervention necessary on any given road at different times for traffic control, such as installation of traffic signals, duration of red, green and yellow lights at intersections, and assignment of traffic control officers near school zones or other relevant locations. In this project, directional patterns are used to detect and count the number of cars in traffic images over a fixed area of the road to determine local traffic intensity. Directional patterns are chosen because they are simple and common to almost all moving vehicles. Perspective vision effects specific to each camera orientation has to be considered, as they affect the size and direction of patterns to be recognized. In this work, a simple and fast algorithm has been developed based on horizontal directional pattern matching and perspective vision adjustment. The results of the algorithm under various conditions are presented and compared in this paper. Using the developed algorithm, the traffic intensity can accurately be determined on clear days with average sized cars. The accuracy is reduced on rainy days when the camera lens contains raindrops, when there are very long vehicles, such as trucks or tankers, in the view, and when there is very low light around dusk or dawn.

Functional Description of Air Traffic Control

DOT National Transportation Integrated Search

1971-04-01

The document contains a description of air traffic control in terms of generic operational functions. The functions are grouped by flight phase and by major system function (navigation, surveillance, control and communication). More detailed descript...

Human resources for the control of road traffic injury.

PubMed

Mock, Charles; Kobusingye, Olive; Anh, Le Vu; Afukaar, Francis; Arreola-Risa, Carlos

2005-04-01

The definition of the ideal numbers and distribution of human resources required for control of road traffic injury (RTI) is not as advanced as for other health problems. We can nonetheless identify functions that need to be addressed across the spectrum of injury control: surveillance; road safety (including infrastructure, vehicle design, and behaviour); and trauma care. Many low-cost strategies to improve these functions in low- or middle-income countries can be identified. For all these strategies, there is need for adequate institutional capacity, including funding, legal authority, and human resources. Several categories of human resources need to be developed: epidemiologists who can handle injury data, design surveillance systems, and undertake research; engineers and planners versed in safety aspects of road design, traffic flow, urban planning, and vehicle design; police and lawyers who understand the health impact of traffic law; clinicians who can develop cost-effective improvements in the entire system of trauma treatment; media experts to undertake effective behaviour change and social marketing; and economists to assist with cost-effectiveness evaluations. RTI control can be strengthened by enhancing such training in these disciplines, as well as encouraging retention of those who have the needed skills. Mechanisms to enhance collaboration between these different fields need to be promoted. Finally, the burden of RTI is borne disproportionately by the poor; in addition to technical issues, more profound equity issues must be addressed. This mandates that people from all professional backgrounds who work for RTI control should develop skills in advocacy and politics.

Human resources for the control of road traffic injury.

PubMed Central

Mock, Charles; Kobusingye, Olive; Anh, Le Vu; Afukaar, Francis; Arreola-Risa, Carlos

2005-01-01

The definition of the ideal numbers and distribution of human resources required for control of road traffic injury (RTI) is not as advanced as for other health problems. We can nonetheless identify functions that need to be addressed across the spectrum of injury control: surveillance; road safety (including infrastructure, vehicle design, and behaviour); and trauma care. Many low-cost strategies to improve these functions in low- or middle-income countries can be identified. For all these strategies, there is need for adequate institutional capacity, including funding, legal authority, and human resources. Several categories of human resources need to be developed: epidemiologists who can handle injury data, design surveillance systems, and undertake research; engineers and planners versed in safety aspects of road design, traffic flow, urban planning, and vehicle design; police and lawyers who understand the health impact of traffic law; clinicians who can develop cost-effective improvements in the entire system of trauma treatment; media experts to undertake effective behaviour change and social marketing; and economists to assist with cost-effectiveness evaluations. RTI control can be strengthened by enhancing such training in these disciplines, as well as encouraging retention of those who have the needed skills. Mechanisms to enhance collaboration between these different fields need to be promoted. Finally, the burden of RTI is borne disproportionately by the poor; in addition to technical issues, more profound equity issues must be addressed. This mandates that people from all professional backgrounds who work for RTI control should develop skills in advocacy and politics. PMID:15868021

47 CFR 2.402 - Control of distress traffic.

Code of Federal Regulations, 2010 CFR

2010-10-01

... distress traffic. The control of distress traffic is the responsibility of the mobile station in distress or of the mobile station which, by the application of the provisions of § 2.403, has sent the...

Microdroplet-etched highly birefringent low-loss fiber tapers.

PubMed

Mikkelsen, Jared C; Poon, Joyce K S

2012-07-01

We use hydrofluoric acid microdroplets to directly etch highly birefringent biconical fiber tapers from standard single-mode fibers. The fiber tapers have micrometer-sized cross sections, which are controlled by the etching condition. The characteristic teardrop cross section leads to a high group birefringence of B(G)≈0.017 and insertion losses <0.7 dB over waist lengths of about 2.1 mm.

Design and Operational Evaluation of the Traffic Management Advisor at the Ft. Worth Air Route Traffic Control Center

NASA Technical Reports Server (NTRS)

Swenson, Harry N.; Vincent, Danny; Tobias, Leonard (Technical Monitor)

1997-01-01

NASA and the FAA have designed and developed and an automation tool known as the Traffic Management Advisor (TMA). The system was operationally evaluated at the Ft. Worth Air Route Traffic Control Center (ARTCC). The TMA is a time-based strategic planning tool that provides Traffic Management Coordinators and En Route Air Traffic Controllers the ability to efficiently optimize the capacity of a demand impacted airport. The TMA consists of trajectory prediction, constraint-based runway scheduling, traffic flow visualization and controllers advisories. The TMA was used and operationally evaluated for forty-one rush traffic periods during a one month period in the Summer of 1996. The evaluations included all shifts of air traffic operations as well as periods of inclement weather. Performance data was collected for engineering and human factor analysis and compared with similar operations without the TMA. The engineering data indicates that the operations with the TMA show a one to two minute per aircraft delay reduction during rush periods. The human factor data indicate a perceived reduction in en route controller workload as well as an increase in job satisfaction. Upon completion of the evaluation, the TMA has become part of the normal operations at the Ft. Worth ARTCC.

Temperature sensing through long period fiber gratings mechanically induced on tapered optical fibers.

PubMed

Pulido-Navarro, María Guadalupe; Escamilla-Ambrosio, Ponciano Jorge; Marrujo-García, Sigifredo; Álvarez-Chávez, José Alfredo; Martínez-Piñón, Fernando

2017-07-01

In this work the feasibility of employing two well-known techniques already used on designing optical fiber sensors is explored. The first technique employed involves monomode tapered fibers, which were fabricated using a taper machine designed, built, and implemented in our laboratory. This implementation greatly reduced the costs and fabrication time allowing us to produce the desired taper length and transmission conditions. The second technique used fiber Bragg gratings, which we decided to have mechanically induced and for that reason we devised and produced our own mechanical gratings with the help of a computer numerical control tool. This grating had to be fabricated with aluminum to withstand temperatures of up to 600°C. When light traveling through an optical fiber reaches a taper it couples into the cladding layer and comes back into the core when the taper ends. In the same manner, when the light encounters gratings in the fiber, it couples to the cladding modes, and when the gratings end, the light couples back into the core. For our experimentation, the tapering machine was programmed to fabricate single-mode tapers with 3 cm length, and the mechanically induced gratings characteristics were 5 cm length, and had a period of 500 μm and depth of the period of 300 μm. For the conducting tests, the tapered fiber is positioned in between two aluminum slabs, one grooved and the other plane. These two blocks accomplish the mechanically induced long period grating (LPG); the gratings on the grooved plaque are imprinted on the taper forming the period gratings. An optical spectrum analyzer is used to observe the changes on the transmission spectrum as the temperature varies from 20°C to 600°C. The resultant attenuation peak wavelength in the transmission spectrum shifts up to 8 nm, which is a higher shift compared to what has been reported using nontapered fibers. As the temperature increases there is no longer a shift, but there is significant power loss

Safe and effective speed reductions for freeway work zones phase 2.

DOT National Transportation Integrated Search

2014-09-01

Freeway preservation projects typically require construction workers to conduct their : work in close proximity to ongoing traffic and often reduce traffic flow to a single lane while work is : undertaken in an adjacent lane. Due to the short-term na...

The design of traffic signal coordinated control

NASA Astrophysics Data System (ADS)

Guo, Xueting; Sun, Hongsheng; Wang, Xifu

2017-05-01

Traffic as the tertiary industry is an important pillar industry to support the normal development of the economy. But now China's road traffic development and economic development has shown a great imbalance and fault phenomenon, which greatly inhibited the normal development of China's economy. Now in many large and medium-sized cities in China are implementing green belt construction. The so-called green band is when the road conditions to meet the conditions for the establishment of the green band, the sections of the intersection of several planning to a traffic coordination control system, so that when the driver at a specific speed can be achieved without stopping the continuous Through the intersection. Green belt can effectively reduce the delay and queuing length of vehicle driving, the normal function of urban roads and reduce the economic losses caused by traffic congestion is a great help. In this paper, the theoretical basis of the design of the coordinated control system is described. Secondly, the green time offset is calculated by the analytic method and the green band is established. And then the VISSIM software is used to simulate the traffic system before and after the improvement. Finally, the results of the two simulations are compared.

Simulation of load traffic and steeped speed control of conveyor

NASA Astrophysics Data System (ADS)

Reutov, A. A.

2017-10-01

The article examines the possibilities of the step control simulation of conveyor speed within Mathcad, Simulink, Stateflow software. To check the efficiency of the control algorithms and to more accurately determine the characteristics of the control system, it is necessary to simulate the process of speed control with real values of traffic for a work shift or for a day. For evaluating the belt workload and absence of spillage it is necessary to use empirical values of load flow in a shorter period of time. The analytical formulas for optimal speed step values were received using empirical values of load. The simulation checks acceptability of an algorithm, determines optimal parameters of regulation corresponding to load flow characteristics. The average speed and the number of speed switching during simulation are admitted as criteria of regulation efficiency. The simulation example within Mathcad software is implemented. The average conveyor speed decreases essentially by two-step and three-step control. A further increase in the number of regulatory steps decreases average speed insignificantly but considerably increases the intensity of the speed switching. Incremental algorithm of speed regulation uses different number of stages for growing and reducing load traffic. This algorithm allows smooth control of the conveyor speed changes with monotonic variation of the load flow. The load flow oscillation leads to an unjustified increase or decrease of speed. Work results can be applied at the design of belt conveyors with adjustable drives.

Application of fiber tapers in astronomy

NASA Astrophysics Data System (ADS)

Marcel, Jaclyn; Haynes, Roger; Bland-Hawthorn, Joss

2006-06-01

Fiber tapers have the potential to significantly advance instrument technology into the realm of fully integrated optical systems. Our initial investigation was directed at the use of fiber tapers as f-ratio transformation devices. Using a technique developed for testing focal ratio degradation (FRD), a collimated light source was injected at different angles into various fiber taper samples and the far-field profile of the fiber output was observed. We compare the FRD present in the optical fiber tapers with conventional fibers and determine how effectively fiber tapers perform as image converters. We demonstrate that while silica fiber tapers may have slightly more intrinsic FRD than conventional fibers they still show promise as adiabatic mode transformers and are worth investigating further for their potential use in astronomical instruments. In this paper we present a brief review of the current status of fiber tapers with particular focus on the astronomical applications. We demonstrate the conservation of etendue in the taper transformation process and present the experimental results for a number of different taper profiles and manufacturers.

Northeastern FIA Tree Taper Study: Current Status and Future Work

Treesearch

James A. Westfall; Charles T. Scott

2005-01-01

The northeastern unit of the Forest Inventory and Analysis program (NE-FIA) is engaged in an ongoing project to develop regionwide tree taper equations. Sampling intensity is based on NE-FIA plot data and is stratified by species, diameter class, and height class. To date, modeling research has been aimed largely at evaluating existing model forms (and hybrids thereof...

Tapered structure construction

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

Smith, Eric D.; Takata, Rosalind K.; Slocum, Alexander H.

Feeding stock used to form a tapered structure into a curving device such that each point on the stock undergoes rotational motion about a peak location of the tapered structure; and the stock meets a predecessor portion of stock along one or more adjacent edges.

In-vehicle work zone messages : final report.

DOT National Transportation Integrated Search

2017-06-01

Work zones present an increased risk to drivers and the work crew. To mitigate these risks, this study investigated the : potential effects of in-vehicle messages to communicate work zone events to the driver. The researchers conducted : literature r...

Multimode Brillouin spectrum in a long tapered birefringent photonic crystal fiber.

PubMed

Tchahame, Joël Cabrel; Beugnot, Jean-Charles; Kudlinski, Alexandre; Sylvestre, Thibaut

2015-09-15

We investigate the stimulated Brillouin scattering (SBS) in a long tapered birefringent solid-core photonic crystal fiber (PCF) and compare our results with a similar but untapered PCF. It is shown that the taper generates a broadband and multipeaked Brillouin spectrum, while significantly increasing the threshold power. Furthermore, we observe that the strong fiber birefringence gives rise to a frequency shift of the Brillouin spectrum which increases along the fiber. Numerical simulations are also presented to account for the taper effect and the birefringence. Our findings open a new means to control or inhibit the SBS by tapering photonic crystal fibers.

Breakdowns in Coordination Between Air Traffic Controllers

NASA Technical Reports Server (NTRS)

Bearman, Chris; Orasanu, Judith; Miller, Ronald C.

2011-01-01

This talk outlines the complexity of coordination in air traffic control, introduces the NextGen technologies, identifies common causes for coordination breakdowns in air traffic control and examines whether these causes are likely to be reduced with the introduction of NextGen technologies. While some of the common causes of breakdowns will be reduced in a NextGen environment this conclusion should be drawn carefully given the current stage of development of the technologies and the observation that new technologies often shift problems rather than reduce them.

Engineering Social Justice into Traffic Control for Self-Driving Vehicles?

PubMed

Mladenovic, Milos N; McPherson, Tristram

2016-08-01

The convergence of computing, sensing, and communication technology will soon permit large-scale deployment of self-driving vehicles. This will in turn permit a radical transformation of traffic control technology. This paper makes a case for the importance of addressing questions of social justice in this transformation, and sketches a preliminary framework for doing so. We explain how new forms of traffic control technology have potential implications for several dimensions of social justice, including safety, sustainability, privacy, efficiency, and equal access. Our central focus is on efficiency and equal access as desiderata for traffic control design. We explain the limitations of conventional traffic control in meeting these desiderata, and sketch a preliminary vision for a next-generation traffic control tailored to address better the demands of social justice. One component of this vision is cooperative, hierarchically distributed self-organization among vehicles. Another component of this vision is a priority system enabling selection of priority levels by the user for each vehicle trip in the network, based on the supporting structure of non-monetary credits.

Susceptibility to anxiety and shift difficulty as determinants of state anxiety in air traffic controllers.

DOT National Transportation Integrated Search

1973-12-01

The State-Trait Anxiety Inventory (STAI) was used to assess the anxiety of air traffic controllers who had experienced difficult and easy work shifts. Eighty volunteers completed the STAI before and after two or more eight-hour work shifts. Controlle...

Effects of heterogeneous traffic with speed limit zone on the car accidents

NASA Astrophysics Data System (ADS)

Marzoug, R.; Lakouari, N.; Bentaleb, K.; Ez-Zahraouy, H.; Benyoussef, A.

2016-06-01

Using the extended Nagel-Schreckenberg (NS) model, we numerically study the impact of the heterogeneity of traffic with speed limit zone (SLZ) on the probability of occurrence of car accidents (Pac). SLZ in the heterogeneous traffic has an important effect, typically in the mixture velocities case. In the deterministic case, SLZ leads to the appearance of car accidents even in the low densities, in this region Pac increases with increasing of fraction of fast vehicles (Ff). In the nondeterministic case, SLZ decreases the effect of braking probability Pb in the low densities. Furthermore, the impact of multi-SLZ on the probability Pac is also studied. In contrast with the homogeneous case [X. Li, H. Kuang, Y. Fan and G. Zhang, Int. J. Mod. Phys. C 25 (2014) 1450036], it is found that in the low densities the probability Pac without SLZ (n = 0) is low than Pac with multi-SLZ (n > 0). However, the existence of multi-SLZ in the road decreases the risk of collision in the congestion phase.

Minimizing the Disruptive Effects of Prospective Memory in Simulated Air Traffic Control

PubMed Central

Loft, Shayne; Smith, Rebekah E.; Remington, Roger

2015-01-01

Prospective memory refers to remembering to perform an intended action in the future. Failures of prospective memory can occur in air traffic control. In two experiments, we examined the utility of external aids for facilitating air traffic management in a simulated air traffic control task with prospective memory requirements. Participants accepted and handed-off aircraft and detected aircraft conflicts. The prospective memory task involved remembering to deviate from a routine operating procedure when accepting target aircraft. External aids that contained details of the prospective memory task appeared and flashed when target aircraft needed acceptance. In Experiment 1, external aids presented either adjacent or non-adjacent to each of the 20 target aircraft presented over the 40min test phase reduced prospective memory error by 11% compared to a condition without external aids. In Experiment 2, only a single target aircraft was presented a significant time (39min–42min) after presentation of the prospective memory instruction, and the external aids reduced prospective memory error by 34%. In both experiments, costs to the efficiency of non-prospective memory air traffic management (non-target aircraft acceptance response time, conflict detection response time) were reduced by non-adjacent aids compared to no aids or adjacent aids. In contrast, in both experiments, the efficiency of the prospective memory air traffic management (target aircraft acceptance response time) was facilitated by adjacent aids compared to non-adjacent aids. Together, these findings have potential implications for the design of automated alerting systems to maximize multi-task performance in work settings where operators monitor and control demanding perceptual displays. PMID:24059825

23 CFR 630.1104 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-04-01

...-aid highway funding. Exposure Control Measures means traffic management strategies to avoid work zone crashes involving workers and motorized traffic by eliminating or reducing traffic through the work zone... including uniformed law enforcement officers, used to reduce the risk of work zone crashes involving...

23 CFR 630.1104 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-04-01

...-aid highway funding. Exposure Control Measures means traffic management strategies to avoid work zone crashes involving workers and motorized traffic by eliminating or reducing traffic through the work zone... including uniformed law enforcement officers, used to reduce the risk of work zone crashes involving...

23 CFR 630.1104 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-04-01

...-aid highway funding. Exposure Control Measures means traffic management strategies to avoid work zone crashes involving workers and motorized traffic by eliminating or reducing traffic through the work zone... including uniformed law enforcement officers, used to reduce the risk of work zone crashes involving...

23 CFR 630.1104 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-04-01

...-aid highway funding. Exposure Control Measures means traffic management strategies to avoid work zone crashes involving workers and motorized traffic by eliminating or reducing traffic through the work zone... including uniformed law enforcement officers, used to reduce the risk of work zone crashes involving...

23 CFR 630.1104 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-04-01

...-aid highway funding. Exposure Control Measures means traffic management strategies to avoid work zone crashes involving workers and motorized traffic by eliminating or reducing traffic through the work zone... including uniformed law enforcement officers, used to reduce the risk of work zone crashes involving...

Ohio manual of uniform traffic control devices [2003

DOT National Transportation Integrated Search

2003-01-01

The purpose of traffic control device and warrants for their use is to help to insure highway safety by providing for the orderly and predictable movement of all traffic and to provide such guidance and warnings as are needed. This manual sets forth ...

Design of a final approach spacing tool for TRACON air traffic control

NASA Technical Reports Server (NTRS)

Davis, Thomas J.; Erzberger, Heinz; Bergeron, Hugh

1989-01-01

This paper describes an automation tool that assists air traffic controllers in the Terminal Radar Approach Control (TRACON) Facilities in providing safe and efficient sequencing and spacing of arrival traffic. The automation tool, referred to as the Final Approach Spacing Tool (FAST), allows the controller to interactively choose various levels of automation and advisory information ranging from predicted time errors to speed and heading advisories for controlling time error. FAST also uses a timeline to display current scheduling and sequencing information for all aircraft in the TRACON airspace. FAST combines accurate predictive algorithms and state-of-the-art mouse and graphical interface technology to present advisory information to the controller. Furthermore, FAST exchanges various types of traffic information and communicates with automation tools being developed for the Air Route Traffic Control Center. Thus it is part of an integrated traffic management system for arrival traffic at major terminal areas.

Cognitive Task Analysis of En Route Air Traffic Control: Model Extension and Validation.

ERIC Educational Resources Information Center

Redding, Richard E.; And Others

Phase II of a project extended data collection and analytic procedures to develop a model of expertise and skill development for en route air traffic control (ATC). New data were collected by recording the Dynamic Simulator (DYSIM) performance of five experts with a work overload problem. Expert controllers were interviewed in depth for mental…

Fuzzy Traffic Control with Vehicle-to-Everything Communication.

PubMed

Salman, Muntaser A; Ozdemir, Suat; Celebi, Fatih V

2018-01-27

Traffic signal control (TSC) with vehicle-to everything (V2X) communication can be a very efficient solution to traffic congestion problem. Ratio of vehicles equipped with V2X communication capability in the traffic to the total number of vehicles (called penetration rate PR) is still low, thus V2X based TSC systems need to be supported by some other mechanisms. PR is the major factor that affects the quality of TSC process along with the evaluation interval. Quality of the TSC in each direction is a function of overall TSC quality of an intersection. Hence, quality evaluation of each direction should follow the evaluation of the overall intersection. Computational intelligence, more specifically swarm algorithm, has been recently used in this field in a European Framework Program FP7 supported project called COLOMBO. In this paper, using COLOMBO framework, further investigations have been done and two new methodologies using simple and fuzzy logic have been proposed. To evaluate the performance of our proposed methods, a comparison with COLOMBOs approach has been realized. The results reveal that TSC problem can be solved as a logical problem rather than an optimization problem. Performance of the proposed approaches is good enough to be suggested for future work under realistic scenarios even under low PR.

Fuzzy Traffic Control with Vehicle-to-Everything Communication

PubMed Central

Ozdemir, Suat; Celebi, Fatih V.

2018-01-01

Traffic signal control (TSC) with vehicle-to everything (V2X) communication can be a very efficient solution to traffic congestion problem. Ratio of vehicles equipped with V2X communication capability in the traffic to the total number of vehicles (called penetration rate PR) is still low, thus V2X based TSC systems need to be supported by some other mechanisms. PR is the major factor that affects the quality of TSC process along with the evaluation interval. Quality of the TSC in each direction is a function of overall TSC quality of an intersection. Hence, quality evaluation of each direction should follow the evaluation of the overall intersection. Computational intelligence, more specifically swarm algorithm, has been recently used in this field in a European Framework Program FP7 supported project called COLOMBO. In this paper, using COLOMBO framework, further investigations have been done and two new methodologies using simple and fuzzy logic have been proposed. To evaluate the performance of our proposed methods, a comparison with COLOMBOs approach has been realized. The results reveal that TSC problem can be solved as a logical problem rather than an optimization problem. Performance of the proposed approaches is good enough to be suggested for future work under realistic scenarios even under low PR. PMID:29382053

Nonlinear acoustic streaming in straight and tapered tubes

NASA Astrophysics Data System (ADS)

Tuttle, Brian C.

In thermoacoustic and Stirling devices such as the pulse-tube refrigerator, efficiency is diminished by the formation of a second-order mean velocity known as Rayleigh streaming. This flow emerges from the interaction of the working gas with the wall of the tube in a thin boundary layer. Recent studies have suggested that streaming velocity can be decreased in a tube by tapering it slightly. This research investigates that claim through the development of a numerical model of Rayleigh streaming in variously tapered tubes. It is found that the numerical simulation of streaming in a straight tube compares well with theory, and the application of different thermal boundary conditions at the tube wall shows that for pressurized helium, inner streaming vortices which appear near an adiabatic tube wall do not develop near an isothermal wall. An order analysis indicates that the temperature dependence of viscosity and thermal conductivity contributes appreciably to an accurate numerical model of streaming. Comparison of Rayleigh streaming in tapered tubes shows the effects of taper angle on the circulation and velocity of the mean flow.

Tapered fiber nanoprobes: plasmonic nanopillars on tapered optical fiber tips for large EM enhancement.

PubMed

Savaliya, Priten; Dhawan, Anuj

2016-10-01

Employing finite difference time domain simulations, we demonstrate that electromagnetic field enhancement is substantially greater for tapered optical fibers with plasmonic nanostructures present on their tips as compared with non-tapered optical fibers having those plasmonic nanostructures, or with tapered optical fibers without the plasmonic nanostructures. We also carried out fabrication of plasmonic nanostructures on optical fiber tips.

Evaluation of radar activated changeable message sign for work zone speed control.

DOT National Transportation Integrated Search

2002-01-01

The Maine Department of Transportation recently tested new equipment designed to help reduce the : incidence of speeding in construction work zones. The project utilized a radar-activated, trailer mounted, : changeable message sign (CMS). The CMS spe...

Application of color to reduce complexity in air traffic control.

DOT National Transportation Integrated Search

2002-11-01

The United States Air Traffic Control (ATC) system is designed to provide for the safe and efficient flow of air : traffic from origin to destination. The Federal Aviation Administration predicts that traffic levels will continue : increasing over th...

In-situ Tapering of Chalcogenide Fiber for Mid-infrared Supercontinuum Generation

PubMed Central

Rudy, Charles W.; Marandi, Alireza; Vodopyanov, Konstantin L.; Byer, Robert L.

2013-01-01

Supercontinuum generation (SCG) in a tapered chalcogenide fiber is desirable for broadening mid-infrared (or mid-IR, roughly the 2-20 μm wavelength range) frequency combs1, 2 for applications such as molecular fingerprinting, 3 trace gas detection, 4 laser-driven particle acceleration, 5 and x-ray production via high harmonic generation. 6 Achieving efficient SCG in a tapered optical fiber requires precise control of the group velocity dispersion (GVD) and the temporal properties of the optical pulses at the beginning of the fiber, 7 which depend strongly on the geometry of the taper. 8 Due to variations in the tapering setup and procedure for successive SCG experiments-such as fiber length, tapering environment temperature, or power coupled into the fiber, in-situ spectral monitoring of the SCG is necessary to optimize the output spectrum for a single experiment. In-situ fiber tapering for SCG consists of coupling the pump source through the fiber to be tapered to a spectral measurement device. The fiber is then tapered while the spectral measurement signal is observed in real-time. When the signal reaches its peak, the tapering is stopped. The in-situ tapering procedure allows for generation of a stable, octave-spanning, mid-IR frequency comb from the sub harmonic of a commercially available near-IR frequency comb. 9 This method lowers cost due to the reduction in time and materials required to fabricate an optimal taper with a waist length of only 2 mm. The in-situ tapering technique can be extended to optimizing microstructured optical fiber (MOF) for SCG10 or tuning of the passband of MOFs, 11 optimizing tapered fiber pairs for fused fiber couplers12 and wavelength division multiplexers (WDMs), 13 or modifying dispersion compensation for compression or stretching of optical pulses.14-16 PMID:23748947

32 CFR 636.21 - Obedience to official traffic control devices.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 32 National Defense 4 2014-07-01 2013-07-01 true Obedience to official traffic control devices... INSTALLATIONS) Fort Stewart, Georgia § 636.21 Obedience to official traffic control devices. (a) All drivers... placed by proper authority. ...

32 CFR 636.21 - Obedience to official traffic control devices.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 4 2010-07-01 2010-07-01 true Obedience to official traffic control devices... INSTALLATIONS) Fort Stewart, Georgia § 636.21 Obedience to official traffic control devices. (a) All drivers... placed by proper authority. ...

32 CFR 636.21 - Obedience to official traffic control devices.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 32 National Defense 4 2013-07-01 2013-07-01 false Obedience to official traffic control devices... INSTALLATIONS) Fort Stewart, Georgia § 636.21 Obedience to official traffic control devices. (a) All drivers... placed by proper authority. ...

32 CFR 636.21 - Obedience to official traffic control devices.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 32 National Defense 4 2012-07-01 2011-07-01 true Obedience to official traffic control devices... INSTALLATIONS) Fort Stewart, Georgia § 636.21 Obedience to official traffic control devices. (a) All drivers... placed by proper authority. ...

32 CFR 636.21 - Obedience to official traffic control devices.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 32 National Defense 4 2011-07-01 2011-07-01 false Obedience to official traffic control devices... INSTALLATIONS) Fort Stewart, Georgia § 636.21 Obedience to official traffic control devices. (a) All drivers... placed by proper authority. ...

Situation awareness information requirements for en route air traffic control.

DOT National Transportation Integrated Search

1994-12-01

Situation awareness is presented as a fundamental requirement for effective air traffic control, forming the basis for controller decision making and performance. To develop a better understanding of the role of situation awareness in air traffic con...

Physiological responses in air traffic control personnel : O'Hare Tower.

DOT National Transportation Integrated Search

1971-01-01

Physiological and biochemical measurements were made on 22 air traffic controllers at O'Hare tower during five days of the heavy traffic evening shift (1600-2400) and five days of the light traffic morning shift (0000-0800). : Pulse rates were higher...

Mobile machine hazardous working zone warning system

DOEpatents

Schiffbauer, William H.; Ganoe, Carl W.

1999-01-01

A warning system is provided for a mobile working machine to alert an individual of a potentially dangerous condition in the event the individual strays into a hazardous working zone of the machine. The warning system includes a transmitter mounted on the machine and operable to generate a uniform magnetic field projecting beyond an outer periphery of the machine in defining a hazardous working zone around the machine during operation thereof. A receiver, carried by the individual and activated by the magnetic field, provides an alarm signal to alert the individual when he enters the hazardous working zone of the machine.

Mobile machine hazardous working zone warning system

DOEpatents

Schiffbauer, W.H.; Ganoe, C.W.

1999-08-17

A warning system is provided for a mobile working machine to alert an individual of a potentially dangerous condition in the event the individual strays into a hazardous working zone of the machine. The warning system includes a transmitter mounted on the machine and operable to generate a uniform magnetic field projecting beyond an outer periphery of the machine in defining a hazardous working zone around the machine during operation. A receiver, carried by the individual and activated by the magnetic field, provides an alarm signal to alert the individual when he enters the hazardous working zone of the machine. 3 figs.

Piloted simulation of a ground-based time-control concept for air traffic control

NASA Technical Reports Server (NTRS)

Davis, Thomas J.; Green, Steven M.

1989-01-01

A concept for aiding air traffic controllers in efficiently spacing traffic and meeting scheduled arrival times at a metering fix was developed and tested in a real time simulation. The automation aid, referred to as the ground based 4-D descent advisor (DA), is based on accurate models of aircraft performance and weather conditions. The DA generates suggested clearances, including both top-of-descent-point and speed-profile data, for one or more aircraft in order to achieve specific time or distance separation objectives. The DA algorithm is used by the air traffic controller to resolve conflicts and issue advisories to arrival aircraft. A joint simulation was conducted using a piloted simulator and an advanced concept air traffic control simulation to study the acceptability and accuracy of the DA automation aid from both the pilot's and the air traffic controller's perspectives. The results of the piloted simulation are examined. In the piloted simulation, airline crews executed controller issued descent advisories along standard curved path arrival routes, and were able to achieve an arrival time precision of + or - 20 sec at the metering fix. An analysis of errors generated in turns resulted in further enhancements of the algorithm to improve the predictive accuracy. Evaluations by pilots indicate general support for the concept and provide specific recommendations for improvement.

Flexible traffic control of the synfire-mode transmission by inhibitory modulation: Nonlinear noise reduction

NASA Astrophysics Data System (ADS)

Shinozaki, Takashi; Okada, Masato; Reyes, Alex D.; Câteau, Hideyuki

2010-01-01

Intermingled neural connections apparent in the brain make us wonder what controls the traffic of propagating activity in the brain to secure signal transmission without harmful crosstalk. Here, we reveal that inhibitory input but not excitatory input works as a particularly useful traffic controller because it controls the degree of synchrony of population firing of neurons as well as controlling the size of the population firing bidirectionally. Our dynamical system analysis reveals that the synchrony enhancement depends crucially on the nonlinear membrane potential dynamics and a hidden slow dynamical variable. Our electrophysiological study with rodent slice preparations show that the phenomenon happens in real neurons. Furthermore, our analysis with the Fokker-Planck equations demonstrates the phenomenon in a semianalytical manner.

Forearc Basin Stratigraphy and Interactions With Accretionary Wedge Growth According to the Critical Taper Concept

NASA Astrophysics Data System (ADS)

Noda, Atsushi

2018-03-01

Forearc basins are important constituents of sediment traps along subduction zones; the basin stratigraphy records various events that the basin experienced. Although the linkage between basin formation and accretionary wedge growth suggests that mass balance exerts a key control on their evolution, the interaction processes between basin and basement remain poorly understood. This study performed 2-D numerical simulations in which basin stratigraphy was controlled by changes in sediment fluxes with accretionary wedge growth according to the critical taper concept. The resultant stratigraphy depended on the degree of filling (i.e., whether the basin was underfilled or overfilled) and the volume balance between the sediment flux supplied to the basin from the hinterland and the accommodation space in the basin. The trenchward progradation of deposition with onlapping contacts on the trenchside basin floor occurred during the underfilled phase, which formed a wedge-shaped sedimentary unit. In contrast, the landward migration of the depocenter, with the tilting of strata, was characteristic for the overfilled phase. Condensed sections marked stratigraphic boundaries, indicating when sediment supply or accommodation space was limited. The accommodation-limited intervals could have formed during the end of wedge uplift or when the taper angle decreased and possibly associated with the development of submarine canyons as conduits for bypassing sediments from the hinterland. Variations in sediment fluxes and their balance exerted a strong influence on the stratigraphic patterns in forearc basins. Assessing basin stratigraphy could be a key to evaluating how subduction zones evolve through their interactions with changing surface processes.

The morbidity experience of air traffic control personnel, 1967-1977.

DOT National Transportation Integrated Search

1978-04-01

The morbidity experience of 28,086 air traffic controllers has been examined from 1967-77 with particular emphasis given the potential effects of job demands on ATC Health. The morbidity experience of air traffic controllers does not appear excessive...

Acoustic vibration sensor based on nonadiabatic tapered fibers.

PubMed

Xu, Ben; Li, Yi; Sun, Miao; Zhang, Zhen-Wei; Dong, Xin-Yong; Zhang, Zai-Xuan; Jin, Shang-Zhong

2012-11-15

A simple and low-cost vibration sensor based on single-mode nonadiabatic fiber tapers is proposed and demonstrated. The environmental vibrations can be detected by demodulating the transmission loss of the nonadiabatic fiber taper. Theoretical simulations show that the transmission loss is related to the microbending of the fiber taper induced by vibrations. Unlike interferometric sensors, this vibration sensor does not need any feedback loop to control the quadrature point to obtain a stable performance. In addition, it has no requirement for the coherence of the light source and is insensitive to temperature changes. Experimental results show that this sensing system has a wide frequency response range from a few hertz to tens of kilohertz with the maximal signal to noise ratio up to 73 dB.

Multiple curved descending approaches and the air traffic control problem

NASA Technical Reports Server (NTRS)

Hart, S. G.; Mcpherson, D.; Kreifeldt, J.; Wemple, T. E.

1977-01-01

A terminal area air traffic control simulation was designed to study ways of accommodating increased air traffic density. The concepts that were investigated assumed the availability of the microwave landing system and data link and included: (1) multiple curved descending final approaches; (2) parallel runways certified for independent and simultaneous operation under IFR conditions; (3) closer spacing between successive aircraft; and (4) a distributed management system between the air and ground. Three groups each consisting of three pilots and two air traffic controllers flew a combined total of 350 approaches. Piloted simulators were supplied with computer generated traffic situation displays and flight instruments. The controllers were supplied with a terminal area map and digital status information. Pilots and controllers also reported that the distributed management procedure was somewhat more safe and orderly than the centralized management procedure. Flying precision increased as the amount of turn required to intersect the outer mark decreased. Pilots reported that they preferred the alternative of multiple curved descending approaches with wider spacing between aircraft to closer spacing on single, straight in finals while controllers preferred the latter option. Both pilots and controllers felt that parallel runways are an acceptable way to accommodate increased traffic density safely and expeditiously.

Tapered GRIN fiber microsensor.

PubMed

Beltrán-Mejía, Felipe; Biazoli, Claudecir R; Cordeiro, Cristiano M B

2014-12-15

The sensitivity of an optical fiber microsensor based on inter-modal interference can be considerably improved by tapering a short extension of the multimode fiber. In the case of Graded Index fibers with a parabolic refractive index profile, a meridional ray exhibits a sinusoidal path. When these fibers are tapered, the period of the propagated beam decrease down-taper and increase up-taper. We take advantage of this modulation -along with the enhanced overlap between the evanescent field and the external medium- to substantially increase the sensitivity of these devices by tuning the sensor's maximum sensitivity wavelength. Moreover, the extension of this device is reduced by one order of magnitude, making it more propitious for reduced space applications. Numerical and experimental results demonstrate the success and feasibility of this approach.

Self-control of traffic lights and vehicle flows in urban road networks

NASA Astrophysics Data System (ADS)

Lämmer, Stefan; Helbing, Dirk

2008-04-01

Based on fluid-dynamic and many-particle (car-following) simulations of traffic flows in (urban) networks, we study the problem of coordinating incompatible traffic flows at intersections. Inspired by the observation of self-organized oscillations of pedestrian flows at bottlenecks, we propose a self-organization approach to traffic light control. The problem can be treated as a multi-agent problem with interactions between vehicles and traffic lights. Specifically, our approach assumes a priority-based control of traffic lights by the vehicle flows themselves, taking into account short-sighted anticipation of vehicle flows and platoons. The considered local interactions lead to emergent coordination patterns such as 'green waves' and achieve an efficient, decentralized traffic light control. While the proposed self-control adapts flexibly to local flow conditions and often leads to non-cyclical switching patterns with changing service sequences of different traffic flows, an almost periodic service may evolve under certain conditions and suggests the existence of a spontaneous synchronization of traffic lights despite the varying delays due to variable vehicle queues and travel times. The self-organized traffic light control is based on an optimization and a stabilization rule, each of which performs poorly at high utilizations of the road network, while their proper combination reaches a superior performance. The result is a considerable reduction not only in the average travel times, but also of their variation. Similar control approaches could be applied to the coordination of logistic and production processes.

Delay-feedback control strategy for reducing CO2 emission of traffic flow system

NASA Astrophysics Data System (ADS)

Zhang, Li-Dong; Zhu, Wen-Xing

2015-06-01

To study the signal control strategy for reducing traffic emission theoretically, we first presented a kind of discrete traffic flow model with relative speed term based on traditional coupled map car-following model. In the model, the relative speed difference between two successive running cars is incorporated into following vehicle's acceleration running equation. Then we analyzed its stability condition with discrete control system stability theory. Third, we designed a delay-feedback controller to suppress traffic jam and decrease traffic emission based on modern controller theory. Last, numerical simulations are made to support our theoretical results, including the comparison of models' stability analysis, the influence of model type and signal control on CO2 emissions. The results show that the temporal behavior of our model is superior to other models, and the traffic signal controller has good effect on traffic jam suppression and traffic CO2 emission, which fully supports the theoretical conclusions.

Analysis of pilot response time to time-critical air traffic control calls

DOT National Transportation Integrated Search

1991-08-01

One of the most important time-critical air traffic control messages for a pilot is one : that required an immediate maneuver for traffic avoidance. This study examines the time : required for an air traffic controller to successfully transmit such a...

Traffic signal control enhancements under vehicle infrastructure integration systems.

DOT National Transportation Integrated Search

2011-12-01

Most current traffic signal systems are operated using a very archaic traffic-detection simple binary : logic (vehicle presence/non presence information). The logic was originally developed to provide input for old : electro-mechanical controllers th...

Evaluation of Work Zone Speed Reduction Measures

DOT National Transportation Integrated Search

2000-04-01

The Iowa Department of Transportation (DOT) has made improving work zone (WZ) safety a high priority. Managing vehicle speeds through work zones is perceived to be an important factor in achieving this goal. A number of speed reduction techniques are...

Advanced interactive display formats for terminal area traffic control

NASA Technical Reports Server (NTRS)

Grunwald, Arthur J.

1995-01-01

The basic design considerations for perspective Air Traffic Control displays are described. A software framework has been developed for manual viewing parameter setting (MVPS) in preparation for continued, ongoing developments on automated viewing parameter setting (AVPS) schemes. The MVPS system is based on indirect manipulation of the viewing parameters. Requests for changes in viewing parameter setting are entered manually by the operator by moving viewing parameter manipulation pointers on the screen. The motion of these pointers, which are an integral part of the 3-D scene, is limited to the boundaries of screen. This arrangement has been chosen, in order to preserve the correspondence between the new and the old viewing parameter setting, a feature which contributes to preventing spatial disorientation of the operator. For all viewing operations, e.g. rotation, translation and ranging, the actual change is executed automatically by the system, through gradual transitions with an exponentially damped, sinusoidal velocity profile, in this work referred to as 'slewing' motions. The slewing functions, which eliminate discontinuities in the viewing parameter changes, are designed primarily for enhancing the operator's impression that he, or she, is dealing with an actually existing physical system, rather than an abstract computer generated scene. Current, ongoing efforts deal with the development of automated viewing parameter setting schemes. These schemes employ an optimization strategy, aimed at identifying the best possible vantage point, from which the Air Traffic Control scene can be viewed, for a given traffic situation.

Vertically-tapered optical waveguide and optical spot transformer formed therefrom

DOEpatents

Bakke, Thor; Sullivan, Charles T.

2004-07-27

An optical waveguide is disclosed in which a section of the waveguide core is vertically tapered during formation by spin coating by controlling the width of an underlying mesa structure. The optical waveguide can be formed from spin-coatable materials such as polymers, sol-gels and spin-on glasses. The vertically-tapered waveguide section can be used to provide a vertical expansion of an optical mode of light within the optical waveguide. A laterally-tapered section can be added adjacent to the vertically-tapered section to provide for a lateral expansion of the optical mode, thereby forming an optical spot-size transformer for efficient coupling of light between the optical waveguide and a single-mode optical fiber. Such a spot-size transformer can also be added to a III-V semiconductor device by post processing.

A novel solution for car traffic control based on radiometric microwave devices

NASA Astrophysics Data System (ADS)

Soldovieri, Francesco; Denisov, Alexander; Speziale, Victor

2014-05-01

The significant problem of traffic in big cities, connected with huge and building up quantity of automobile cars, demands for novel strategies, based on nonconventional solutions, in order to improve system traffic control, especially at crossroads. As well known, the usual solution is based on the time relay, which requires the installation of a fixed traffic interval (signal light switching) at a crossroad; this solution is low cost, but does not account for the actual traffic conditions. Therefore, in the recent years, attention is towards to new designs, where the monitoring of the and control of traffic is carried out by using various methods including, optical, the infrared, magnetic, radar tracking, acoustical ones. In this work, we discuss the deployment of high sensitivity radiometric systems and radiometers(sensor) in the microwave range [1, 2]. In fact, the radiometer as "sensor" can provide an always updated information about the car traffic in any weather condition and in absence or low visibility conditions. In fact, the radiometric sensor detects the cars thanks to the different behavior of the car roofs which reflect the cold sky whereas the road asphalt is visible as warm object (at around outside temperature). [1] A. G. Denisov, V. P. Gorishnyak, S. E. Kuzmin et al., "Some experiments concerning resolution of 32 sensors passive 8mm wave imaging system," in Proceedings of the International Symposium on Space Terahertz Technology (ISSTT '09), Charlottesville, Va, USA, April 2009. [2] F. Soldovieri, A. Natale, V. Gorishnyak, A. Pavluchenko, A. Denisov, and L. Chen, "Radiometric Imaging for Monitoring and Surveillance Issues," International Journal of Antennas and Propagation, vol. 2013, Article ID 272561, 8 pages, 2013. doi:10.1155/2013/272561.

Active Work Zone Safety Using Emerging Technologies 2017.

DOT National Transportation Integrated Search

2017-07-01

Highway construction work zones are hazardous environments characterized by a dynamic and limited work space. A host of interactions between workers, passing commuter vehicles, and moving construction equipment occurs in highway work zones fostering ...

STIR-Physics: Cold Atoms and Nanocrystals in Tapered Nanofiber and High-Q Resonator Potentials

DTIC Science & Technology

2016-11-02

STIR- Physics : Cold Atoms and Nanocrystals in Tapered Nanofiber and High-Q Resonator Potentials We worked on a tapered fiber in cold atomic cloud...reviewed journals: Number of Papers published in non peer-reviewed journals: Final Report: STIR- Physics : Cold Atoms and Nanocrystals in Tapered Nanofiber...other than abstracts): Number of Peer-Reviewed Conference Proceeding publications (other than abstracts): Books Number of Manuscripts: 0.00Number of

Lattice hydrodynamic model based traffic control: A transportation cyber-physical system approach

NASA Astrophysics Data System (ADS)

Liu, Hui; Sun, Dihua; Liu, Weining

2016-11-01

Lattice hydrodynamic model is a typical continuum traffic flow model, which describes the jamming transition of traffic flow properly. Previous studies in lattice hydrodynamic model have shown that the use of control method has the potential to improve traffic conditions. In this paper, a new control method is applied in lattice hydrodynamic model from a transportation cyber-physical system approach, in which only one lattice site needs to be controlled in this control scheme. The simulation verifies the feasibility and validity of this method, which can ensure the efficient and smooth operation of the traffic flow.

Optimised process for fabricating tapered long period gratings

NASA Astrophysics Data System (ADS)

Mullaney, K.; Staines, S. E.; James, S. W.; Tatam, R. P.

2017-04-01

The process of fabricating tapered long period gratings (TLPGs) using a CO2 laser is described. TLPGs with a period spacing of 378 μm, were fabricated by optimization of the taper waist diameter and careful control of the duty-cycle and its uniformity along the length of the grating. The 6-period TLPGs exhibited a pass-band insertion loss of 0.6 dB, resonance band extinction values of 3 dB and had a physical length of 2.27 mm.

Airport Surface Traffic Control Systems Deployment Analysis

DOT National Transportation Integrated Search

1974-01-01

The report summarizes the findings of an analysis of ASTC (Airport Surface Traffic Control) system requirements and develops estimates of the deployment potential of proposed system alternatives. The tower control problem areas were investigated by a...

Buprenorphine tapering schedule and illicit opioid use

PubMed Central

Ling, Walter; Hillhouse, Maureen; Domier, Catherine; Doraimani, Geetha; Hunter, Jeremy; Thomas, Christie; Jenkins, Jessica; Hasson, Albert; Annon, Jeffrey; Saxon, Andrew; Selzer, Jeffrey; Boverman, Joshua; Bilangi, Richard

2011-01-01

Aims To compare the effects of a short or long taper schedule after buprenorphine stabilization on participant outcomes as measured by opioid-free urine tests at the end of each taper period. Design This multi-site study sponsored by Clinical Trials Network (CTN, a branch of the US National Institute on Drug Abuse) was conducted from 2003 to 2005 to compare two taper conditions (7 days and 28 days). Data were collected at weekly clinic visits to the end of the taper periods, and at 1-month and 3-month post-taper follow-up visits. Setting Eleven out-patient treatment programs in 10 US cities. Intervention Non-blinded dosing with Suboxone® during the 1-month stabilization phase included 3 weeks of flexible dosing as determined appropriate by the study physicians. A fixed dose was required for the final week before beginning the taper phase. Measurements The percentage of participants in each taper group providing urine samples free of illicit opioids at the end of the taper and at follow-up. Findings At the end of the taper, 44% of the 7-day taper group (n = 255) provided opioid-free urine specimens compared to 30% of the 28-day taper group (n = 261; P = 0.0007). There were no differences at the 1-month and 3-month follow-ups (7-day = 18% and 12%; 28-day = 18% and 13%, 1 month and 3 months, respectively). Conclusion For individuals terminating buprenorphine pharmacotherapy for opioid dependence, there appears to be no advantage in prolonging the duration of taper. PMID:19149822

Remotely Accessed Vehicle Traffic Management System

NASA Astrophysics Data System (ADS)

Al-Alawi, Raida

2010-06-01

The ever increasing number of vehicles in most metropolitan cities around the world and the limitation in altering the transportation infrastructure, led to serious traffic congestion and an increase in the travelling time. In this work we exploit the emergence of novel technologies such as the internet, to design an intelligent Traffic Management System (TMS) that can remotely monitor and control a network of traffic light controllers located at different sites. The system is based on utilizing Embedded Web Servers (EWS) technology to design a web-based TMS. The EWS located at each intersection uses IP technology for communicating remotely with a Central Traffic Management Unit (CTMU) located at the traffic department authority. Friendly GUI software installed at the CTMU will be able to monitor the sequence of operation of the traffic lights and the presence of traffic at each intersection as well as remotely controlling the operation of the signals. The system has been validated by constructing a prototype that resembles the real application.

Air-Traffic Controllers Evaluate The Descent Advisor

NASA Technical Reports Server (NTRS)

Tobias, Leonard; Volckers, Uwe; Erzberger, Heinz

1992-01-01

Report describes study of Descent Advisor algorithm: software automation aid intended to assist air-traffic controllers in spacing traffic and meeting specified times or arrival. Based partly on mathematical models of weather conditions and performances of aircraft, it generates suggested clearances, including top-of-descent points and speed-profile data to attain objectives. Study focused on operational characteristics with specific attention to how it can be used for prediction, spacing, and metering.

Comparison of subjective symptoms and cold prevention measures in winter between traffic control workers and construction workers in Japan.

PubMed

Inaba, Ryoichi; Kurokawa, Junichi; Mirbod, Seyed Mohammad

2009-07-01

To help making comfortable workplaces and to prevent health disorders induced by the exposure to moderate cold in two different groups of out-door workers, we conducted a survey to compare subjective symptoms and cold prevention measures in winter between traffic control workers and construction workers. The subjects of this study were 98 male traffic control workers and 149 male workers engaged in building construction. Work loads of traffic control workers and construction workers were estimated at RMR1-2 and RMR2-4, respectively. All subjects were asked to complete a self-administered questionnaire covering age, occupational career, working figure, present illness, past history of diseases, individual preventive measures to the cold, subjective symptoms in the winter (43 items) and subjective symptoms occurred during daytime working in the winter (6 items). In two parts of the construction workplaces (the place where a morning assembly was held and on the 7th floor of the construction site) dry bulb, wet bulb and globe temperatures were measured in January. Windchill Index (kcal/cm,(2) x h) was calculated by the measured dry bulb temperature and wind velocity. Mean values of dry bulb temperature between 9:00 and 16:30 in the place where a morning assembly was held for three days were between 4.8 +/- 1.2 degrees C at 9:00 am and 9.3 +/- 1.1 degrees C at noon. Mean values of Windchill Index in the place where a morning assembly was held were between 490.8+/-23.9 kcal/cm(2) x h at 9:30 am and 608.2+/-47.3 kcal/cm(2) x h at 2:30 pm. Occupational career, monthly working days, daily working hours, one way commuting hours, and daily smoking numbers of the traffic control workers were significantly shorter than the construction workers (p<0.01). There were no significant differences in the prevalence of chillness in the arms and legs between the traffic control workers (5.1%) and the construction workers (0.7%). Prevalence of wearing a warm underwear, body warmer, warm

Experimental design rules for implementing biconically tapered single mode optical fibre displacement sensors

NASA Astrophysics Data System (ADS)

Arregui, Francisco J.; Matias, Ignacio R.; Bariain, Candido; Lopez-Amo, Manuel

1998-06-01

Tapered optical fibers are used to design couplers, wavelength division multiplexers, near field scanning optical microscopy, just to mention a few. Moreover, and due to its strong transmission dependence to external medium the tapered fiber may also be used to sense distinct parameters such as temperature, humidity, PH, etc. In this work bending effects in tapers are exploited to achieved displacement sensors and to present design rules for implementing these sensors according to the desired both range and sensitivity.

Transforming the NAS: The Next Generation Air Traffic Control System

NASA Technical Reports Server (NTRS)

Erzberger, Heinz

2004-01-01

The next-generation air traffic control system must be designed to safely and efficiently accommodate the large growth of traffic expected in the near future. It should be sufficiently scalable to contend with the factor of 2 or more increase in demand expected by the year 2020. Analysis has shown that the current method of controlling air traffic cannot be scaled up to provide such levels of capacity. Therefore, to achieve a large increase in capacity while also giving pilots increased freedom to optimize their flight trajectories requires a fundamental change in the way air traffic is controlled. The key to achieving a factor of 2 or more increase in airspace capacity is to automate separation monitoring and control and to use an air-ground data link to send trajectories and clearances directly between ground-based and airborne systems. In addition to increasing capacity and offering greater flexibility in the selection of trajectories, this approach also has the potential to increase safety by reducing controller and pilot errors that occur in routine monitoring and voice communication tasks.

An RFID-based intelligent vehicle speed controller using active traffic signals.

PubMed

Pérez, Joshué; Seco, Fernando; Milanés, Vicente; Jiménez, Antonio; Díaz, Julio C; de Pedro, Teresa

2010-01-01

These days, mass-produced vehicles benefit from research on Intelligent Transportation System (ITS). One prime example of ITS is vehicle Cruise Control (CC), which allows it to maintain a pre-defined reference speed, to economize on fuel or energy consumption, to avoid speeding fines, or to focus all of the driver's attention on the steering of the vehicle. However, achieving efficient Cruise Control is not easy in roads or urban streets where sudden changes of the speed limit can happen, due to the presence of unexpected obstacles or maintenance work, causing, in inattentive drivers, traffic accidents. In this communication we present a new Infrastructure to Vehicles (I2V) communication and control system for intelligent speed control, which is based upon Radio Frequency Identification (RFID) technology for identification of traffic signals on the road, and high accuracy vehicle speed measurement with a Hall effect-based sensor. A fuzzy logic controller, based on sensor fusion of the information provided by the I2V infrastructure, allows the efficient adaptation of the speed of the vehicle to the circumstances of the road. The performance of the system is checked empirically, with promising results.

An RFID-Based Intelligent Vehicle Speed Controller Using Active Traffic Signals

PubMed Central

Pérez, Joshué; Seco, Fernando; Milanés, Vicente; Jiménez, Antonio; Díaz, Julio C.; de Pedro, Teresa

2010-01-01

These days, mass-produced vehicles benefit from research on Intelligent Transportation System (ITS). One prime example of ITS is vehicle Cruise Control (CC), which allows it to maintain a pre-defined reference speed, to economize on fuel or energy consumption, to avoid speeding fines, or to focus all of the driver’s attention on the steering of the vehicle. However, achieving efficient Cruise Control is not easy in roads or urban streets where sudden changes of the speed limit can happen, due to the presence of unexpected obstacles or maintenance work, causing, in inattentive drivers, traffic accidents. In this communication we present a new Infrastructure to Vehicles (I2V) communication and control system for intelligent speed control, which is based upon Radio Frequency Identification (RFID) technology for identification of traffic signals on the road, and high accuracy vehicle speed measurement with a Hall effect-based sensor. A fuzzy logic controller, based on sensor fusion of the information provided by the I2V infrastructure, allows the efficient adaptation of the speed of the vehicle to the circumstances of the road. The performance of the system is checked empirically, with promising results. PMID:22219692

Narrowband spectral filter based on biconical tapered fiber

NASA Astrophysics Data System (ADS)

Celaschi, Sergio; Malheiros-Silveira, Gilliard N.

2018-02-01

The ease of fabrication and compactness of devices based on tapered optical fibers contribute to its potential using in several applications ranging from telecommunication components to sensing devices. In this work, we proposed, fabricated, and characterized a spectral filter made of biconical taper from a coaxial optical fiber. This filter is defined by adiabatically tapering a depressed-cladding fiber. The adiabatic taper profile obtained during fabrication prevents the interference of other modes than HE11 and HE12 ones, which play the main role for the beating phenomenon and the filter response. The evolution of the fiber shapes during the pulling was modeled by two coupled partial differential equations, which relate the normalized cross-section area, and the axial velocity of the fiber elongation. These equations govern the mass and axial momentum conservation. The numerical results of the filter characteristics are in good accordance with the experimental ones. The filter was packaged in order to let it ready for using in optical communication bands. The characteristics are: free spectral range (FSR) of 6.19 nm, insertion loss bellow 0.5 dB, and isolation > 20 dB at C-band. Its transmission spectrum extends from 1200 to 1600 nm where the optical fiber core supports monomode transmission. Such characteristics may also be interesting to be applied in sensing applications. We show preliminary numerical results assuming a biconic taper embedded into a dielectric media, showing promising results for electro-optic sensing applications.

Communications Handbook for Traffic Control Systems

DOT National Transportation Integrated Search

1993-04-01

The communications system generally proves the most critical and expensive element of a traffic control system/IVHS. Therefore the successful design, implementation, and operation of the communications system become key to the effectiveness of the ov...

The Air Traffic Control Environment in 2010

DOT National Transportation Integrated Search

1989-10-01

This document has been prepared to assist the Airspace Control Planning Panel by describing the broad outline and general features of the environment for air traffic control functions anticipated in the 2010 timeframe. The description is based on est...

Development of a photogrammetric method of measuring tree taper outside bark

Treesearch

David R. Larsen

2006-01-01

A photogrammetric method is presented for measuring tree diameters outside bark using calibrated control ground-based digital photographs. The method was designed to rapidly collect tree taper information from subject trees for the development of tree taper equations. Software that is commercially available, but designed for a different purpose, can be readily adapted...

Efficient Conversation: The Talk between Pilots and Air Traffic Controllers.

ERIC Educational Resources Information Center

Simmons, James L.

Two-way radio communications between air traffic controllers using radar on the ground to give airplane pilots instructions are of interest within the developing framework of the sociology of language. The main purpose of air traffic control language is efficient communication to promote flight safety. This study describes the standardized format…

Evaluation of traffic responsive control on the Reston Parkway arterial network.

DOT National Transportation Integrated Search

2009-01-01

Traffic responsive plan selection (TRPS) control is considered an effective operational mode in traffic signal systems. Its efficiency stems from the fact that it can capture variations in traffic patterns and switch timing plans based on existing tr...

Validation of air traffic controller workload models

DOT National Transportation Integrated Search

1979-09-01

During the past several years, computer models have been developed for off-site : estimat ion of control ler's workload. The inputs to these models are audio and : digital data normally recorded at an Air Route Traffic Control Center (ARTCC). : This ...

LaGuardia air traffic control tower.

DOT National Transportation Integrated Search

2011-01-01

To celebrate FAA and its LaGuardia Airport employees past, : present, and future this booklet outlines the airports history and accomplishments and includes copies of some of the photographs in the : air traffic control towers history g...

The Conception Approach to the Traffic Control in Czech Cities - Examples from Prague

NASA Astrophysics Data System (ADS)

Tichý, Tomáš; Krajčír, Dušan

Modern and economic development of contemporary towns is without question highly dependent upon traffic infrastructure progress. Automobile transport intensity is dramatically rising in large towns and other Czech and European cities. At the same time number of traffic congestions and accidents is increasing, standing times are becoming longer and ecological stress is also escalated. To solve this situation seems to be the most effective solution to design intelligent traffic light intersection control system, variable message signs, preference of public transportation, road line traffic control and next telematics subsystems. This control system and subsystems should improve permeability of traffic road network with a respect for all demands on recent trends of traffic development in towns and regions.

Houston Intercontinental and William P. Hobby Air Traffic Control System Analysis

DOT National Transportation Integrated Search

1982-06-01

This report provides a decription of the non-surveillance aspects of the FAA air traffic control facility operation at Houston Intercontinental and William P. Hobby Airports from teh air traffic controller's point of view. It includes photographs of ...

Practical color vision tests for air traffic control applicants : en route center and terminal facilities.

DOT National Transportation Integrated Search

1995-04-01

Two practical color vision tests were developed and validated for use in screening Air Traffic Control specialist (ATCS) applicants for work at en route center or terminal facilities. The development of the tests involved careful reproduction/simulat...

Monitoring the fabrication of tapered optical fibres

NASA Astrophysics Data System (ADS)

Mullaney, K.; Correia, R.; Staines, S. E.; James, S. W.; Tatam, R. P.

2017-04-01

A variety of optical methods to enhance the process of making optical fibre tapers are explored. A thermal camera was used to both refine the alignment of the optical components and optimize the laser power profile during the tapering process. The fibre transmission was measured to verify that the tapers had the requisite optical characteristics while the strain experienced by the fibre while tapering was assessed using an optical fibre Bragg grating. Using these techniques, adiabatic tapers were fabricated with a 2% insertion loss.

Street deployment of pedestrian control smart traffic signals.

DOT National Transportation Integrated Search

2009-04-01

Smart Signals is a term used to describe the application of network based distributed control technology to the control of traffic signals at signalized intersections. Presently, signalized intersections use a centralized control approach where all o...

Anthropometry of air traffic control trainees.

DOT National Transportation Integrated Search

1965-09-01

This report presents the body measurements of 684 air traffic control trainees enrolled in training programs conducted at the Federal Aviation Agency Aeronautical Center at Oklahoma City between August 12, 1960, and June 30, 1961. It includes the mea...

Energy consumption of ProTaper Next X1 after glide path with PathFiles and ProGlider.

PubMed

Berutti, Elio; Alovisi, Mario; Pastorelli, Michele Angelo; Chiandussi, Giorgio; Scotti, Nicola; Pasqualini, Damiano

2014-12-01

Instrument failure caused by excessive torsional stress can be controlled by creating a manual or mechanical glide path. The ProGlider single-file system (Dentsply Maillefer, Ballaigues, Switzerland) was recently introduced to perform a mechanical glide path. This study was designed to compare the effect of a glide path performed with PathFiles (Dentsply Maillefer) and ProGlider on torque, time, and pecking motion required for ProTaper Next X1 (Dentsply Maillefer) to reach the full working length in simulated root canals. Forty Endo Training Blocks (Dentsply Maillefer) were used. Twenty were prepared with a mechanical glide path using PathFiles 1 and 2 (the PathFile group), and 20 were prepared with a mechanical glide path using a ProGlider single file (the ProGlider group). All samples were shaped with ProTaper Next X1 driven by an endodontic motor connected to a digital wattmeter. The required torque for root canal instrumentation was analyzed by evaluating the electrical power consumption of the endodontic engine. Electric power consumption (mW/h), elapsed time (seconds), and number of pecking motions required to reach the full working length with ProTaper Next X1 were calculated. Differences among groups were analyzed with the parametric Student t test for independent data (P < .05). Elapsed time and electric power consumption were significantly different between groups (P = .0001 for both). ProGlider appears to perform more efficiently than PathFiles in decreasing electric power consumption of ProTaper Next X1 to reach the full working length. This study confirmed the ability of ProGlider to reduce stress in ProTaper Next X1 during shaping through a glide path and preliminary middle and coronal preflaring. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Development and MASH full-scale crash testing of a high-mounting-height temporary single sign support with aluminum sign.

DOT National Transportation Integrated Search

2013-03-01

Work zone traffic control devices such as temporary single sign supports are a primary means to communicate : information to motorists in work zone areas. The Federal Highway Administration and the Manual on Uniform Traffic : Control Devices require ...

Human factors in air traffic control: problems at the interfaces.

PubMed

Shouksmith, George

2003-10-01

The triangular ISIS model for describing the operation of human factors in complex sociotechnical organisations or systems is applied in this research to a large international air traffic control system. A large sample of senior Air Traffic Controllers were randomly assigned to small focus discussion groups, whose task was to identify problems occurring at the interfaces of the three major human factor components: individual, system impacts, and social. From these discussions, a number of significant interface problems, which could adversely affect the functioning of the Air Traffic Control System, emerged. The majority of these occurred at the Individual-System Impact and Individual-Social interfaces and involved a perceived need for further interface centered training.

Development concerns for satellite-based air traffic control surveillance systems

NASA Technical Reports Server (NTRS)

Mcdonald, K. D.

1985-01-01

Preliminary results of an investigation directed toward the configuration of a practical system design which can form the baseline for assessing the applications and value of a satellite based air traffic surveillance system for future use in the National Airspace System (NAS) are described. This work initially studied the characteristics and capabilities of a satellite configuration which would operate compatibly with the signal structure and avionics of the next generation air traffic control secondary surveillance radar system, the Mode S system. A compatible satellite surveillance system concept is described and an analysis is presented of the link budgets for the various transmission paths. From this, the satellite characteristics are established involving a large multiple feed L band antenna of approximately 50 meter aperture dimension. Trade offs involved in several of the alternative large aperture antennas considered are presented as well as the influence of various antenna configurations on the performance capabilities of the surveillance system. The features and limitations of the use of large aperture antenna systems for air traffic surveillance are discussed. Tentative results of this continuing effort are summarized with a brief description of follow on investigations involving other space based antenna systems concepts.

Prediction algorithms for urban traffic control

DOT National Transportation Integrated Search

1979-02-01

The objectives of this study are to 1) review and assess the state-of-the-art of prediction algorithms for urban traffic control in terms of their accuracy and application, and 2) determine the prediction accuracy obtainable by examining the performa...

Traffic control device conspicuity, TechBrief

DOT National Transportation Integrated Search

2013-09-01

The conspicuity of a traffic control device (TCD) is defined as the probability that the device will be noticed. However, there is no agreed-upon measure of what constitutes being noticed. Various measures such as eye fixations, recall, and other ver...

Procedural errors in air traffic control: effects of traffic density, expertise, and automation.

PubMed

Di Nocera, Francesco; Fabrizi, Roberto; Terenzi, Michela; Ferlazzo, Fabio

2006-06-01

Air traffic management requires operators to frequently shift between multiple tasks and/or goals with different levels of accomplishment. Procedural errors can occur when a controller accomplishes one of the tasks before the entire operation has been completed. The present study had two goals: first, to verify the occurrence of post-completion errors in air traffic control (ATC) tasks; and second, to assess effects on performance of medium term conflict detection (MTCD) tools. There were 18 military controllers who performed a simulated ATC task with and without automation support (MTCD vs. manual) in high and low air traffic density conditions. During the task, which consisted of managing several simulated flights in an enroute ATC scenario, a trace suddenly disappeared "after" the operator took the aircraft in charge, "during" the management of the trace, or "before" the pilot's first contact. In the manual condition, only the fault type "during" was found to be significantly different from the other two. On the contrary, when in the MTCD condition, the fault type "after" generated significantly less errors than the fault type "before." Additionally, automation was found to affect performance of junior controllers, whereas seniors' performance was not affected. Procedural errors can happen in ATC, but automation can mitigate this effect. Lack of benefits for the "before" fault type may be due to the fact that operators extend their reliance to a part of the task that is unsupported by the automated system.

Intelligent Transportation Systems in Work Zones - A Case Study: Work Zone Travel Time System. Reducing Congestion with the Use of a Traffic Management Contract Incentive during the Reconstruction of Arizona State Route 68

DOT National Transportation Integrated Search

2004-10-01

This case study is one in a series of documents that examines the use of Intelligent Transportation Systems (ITS) in work zones. This case study presents information gathered through interviews with key personnel on the Arizona State Route (SR) 68 pr...

In-Trail Procedure Air Traffic Control Procedures Validation Simulation Study

NASA Technical Reports Server (NTRS)

Chartrand, Ryan C.; Hewitt, Katrin P.; Sweeney, Peter B.; Graff, Thomas J.; Jones, Kenneth M.

2012-01-01

In August 2007, Airservices Australia (Airservices) and the United States National Aeronautics and Space Administration (NASA) conducted a validation experiment of the air traffic control (ATC) procedures associated with the Automatic Dependant Surveillance-Broadcast (ADS-B) In-Trail Procedure (ITP). ITP is an Airborne Traffic Situation Awareness (ATSA) application designed for near-term use in procedural airspace in which ADS-B data are used to facilitate climb and descent maneuvers. NASA and Airservices conducted the experiment in Airservices simulator in Melbourne, Australia. Twelve current operational air traffic controllers participated in the experiment, which identified aspects of the ITP that could be improved (mainly in the communication and controller approval process). Results showed that controllers viewed the ITP as valid and acceptable. This paper describes the experiment design and results.

Display concepts for en route air traffic control.

DOT National Transportation Integrated Search

2001-02-01

Previous research in the domain of air traffic control (ATC) has explored factors that describe the complexity facing a controller. : Based on this research, new technologies and procedures have been developed that may aid the controller and reduce t...

Tour time in a two-route traffic system controlled by signals

NASA Astrophysics Data System (ADS)

Nagatani, Takashi; Naito, Yuichi

2011-11-01

We study the dynamic behavior of vehicular traffic in a two-route system with a series of signals (traffic lights) at low density where the number of signals on route A is different from that on route B. We investigate the dependence of the tour time on the route for some strategies of signal control. The nonlinear dynamic model of a two-route traffic system controlled by signals is presented by nonlinear maps. The vehicular traffic exhibits a very complex behavior, depending on the cycle time, the phase difference, and the irregularity. The dependence of the tour time on the route choice is clarified for the signal strategies.

Flight to the future : human factors in air traffic control

DOT National Transportation Integrated Search

1997-01-01

The nation's air traffic control system is responsible for managing a complex : mixture of air traffic from commercial, general, corporate, and military : aviation. Despite a strong safety record, the system does suffer occasional : serious disruptio...

AMPO Travel Modeling Working Group Meeting on Dynamic Traffic Assignment

DOT National Transportation Integrated Search

2016-03-01

On December 17-18, 2015, the Association of Metropolitan Planning Organizations (AMPO) convened a travel modeling working group meeting for the purpose of discussing Dynamic Traffic Assignment (DTA). Participants discussed the uses of DTA, challenges...

TASAR Flight Trial 2: Assessment of Air Traffic Controller Acceptability of TASAR Requests

NASA Technical Reports Server (NTRS)

Idris, Husni; Enea, Gabriele

2016-01-01

In support of the Flight Trial (FT-2) of NASA's prototype of the Traffic Aware Strategic Aircrew Requests (TASAR) concept, observations were conducted at the air traffic facilities to identify and assess the main factors that affect the acceptability of pilot requests by air traffic controllers. Two observers shadowed air traffic controllers at the Atlanta (ZTL) and Jacksonville (ZJX) air traffic control centers as the test flight pilot made pre-scripted requests to invoke acceptability issues and then they interviewed the observed and other controllers voluntarily. Fifty controllers were interviewed with experience ranging from one to thirty-five years. All interviewed controllers were enthusiastic about the technology and accounting for sector boundaries in pilot requests, particularly if pilots can be made aware of high workload situations. All interviewed controllers accept more than fifty percent of pilot requests; forty percent of them reject less than ten percent of requests. The most common reason for rejecting requests is conflicting with traffic followed by violating letters of agreement (LOAs) and negatively impacting neighboring sector workload, major arrival and departure flows and flow restrictions. Thirty-six requests were made during the test, eight of which were rejected due to: the aircraft already handed off to another sector, violating LOA, opposing traffic, intruding into an active special use airspace (SUA), intruding into another center, weather, and unfamiliarity with the requested waypoint. Nine requests were accepted with delay mostly because the controller needed to locate unfamiliar waypoints or to coordinate with other controllers.

Tapering Practices of Croatian Open-Class Powerlifting Champions.

PubMed

Grgic, Jozo; Mikulic, Pavle

2017-09-01

Grgic, J and Mikulic, P. Tapering practices of Croatian open-class powerlifting champions. J Strength Cond Res 31(9): 2371-2378, 2017-The aim of this study was to explore tapering practices among 10 Croatian open-class powerlifting champions (mean ± SD: age 29.2 ± 3.2 years; Wilks coefficient 355.1 ± 54.8). The athletes were interviewed about their tapering practices using a semi-structured interview after which the audio content was transcribed. The athletes reported decreasing training volume during the taper by 50.5 ± 11.7% using a step type or an exponential type of taper with a fast decay. Training intensity was maintained or increased during the taper, and it reached its highest values 8 ± 3 days before the competition. Training frequency was reduced or maintained during the taper. The final week included a reduction in training frequency by 47.9 ± 17.5% with the last training session performed 3 ± 1 days before the competition. The participants typically stated that the main reasons for conducting the taper were maintaining strength and reducing the amount of fatigue. They also stated that (a) the taper was structured identically for the squat, bench press, and the deadlift; (b) the training during the taper was highly specific, the assistance exercises were removed, and the same equipment was used as during competition; (c) the source of information for tapering was their coach, and training fluctuated based on the coach's feedback; and (d) nutrition, foam rolling, static stretching, and massage were all given extra attention during the taper. These results may aid athletes and coaches in strength sports in terms of the optimization of tapering variables.

The Effectiveness of Yoga on Spiritual Intelligence in Air Traffic Controllers of Tehran Flight Control Center

ERIC Educational Resources Information Center

Safara, Maryam; Ghasemi, Pejman

2017-01-01

The aim of this study was to evaluate the efficacy of yoga on spiritual intelligence in air traffic controllers in Tehran flight control center. This was a quasi-experimental research and the study population includes all air traffic controllers in Tehran flight control center. The sample consisted of 40 people of the study population that were…

Mechanics of the tapered interference fit in dental implants.

PubMed

Bozkaya, Dinçer; Müftü, Sinan

2003-11-01

In evaluation of the long-term success of a dental implant, the reliability and the stability of the implant-abutment interface plays a great role. Tapered interference fits provide a reliable connection method between the abutment and the implant. In this work, the mechanics of the tapered interference fits were analyzed using a closed-form formula and the finite element (FE) method. An analytical solution, which is used to predict the contact pressure in a straight interference, was modified to predict the contact pressure in the tapered implant-abutment interface. Elastic-plastic FE analysis was used to simulate the implant and abutment material behavior. The validity and the applicability of the analytical solution were investigated by comparisons with the FE model for a range of problem parameters. It was shown that the analytical solution could be used to determine the pull-out force and loosening-torque with 5-10% error. Detailed analysis of the stress distribution due to tapered interference fit, in a commercially available, abutment-implant system was carried out. This analysis shows that plastic deformation in the implant limits the increase in the pull-out force that would have been otherwise predicted by higher interference values.

Automated mixed traffic vehicle control and scheduling study

NASA Technical Reports Server (NTRS)

Peng, T. K. C.; Chon, K.

1976-01-01

The operation and the expected performance of a proposed automatic guideway transit system which uses low speed automated mixed traffic vehicles (AMTVs) were analyzed. Vehicle scheduling and headway control policies were evaluated with a transit system simulation model. The effect of mixed traffic interference on the average vehicle speed was examined with a vehicle pedestrian interface model. Control parameters regulating vehicle speed were evaluated for safe stopping and passenger comfort. Some preliminary data on the cost and operation of an experimental AMTV system are included. These data were the result of a separate task conducted at JPL, and were included as background information.

A sensemaking perspective on framing the mental picture of air traffic controllers.

PubMed

Malakis, Stathis; Kontogiannis, Tom

2013-03-01

It has long been recognized that controller strategies are based on a 'mental picture' or representation of traffic situations. Earlier studies indicated that controllers tend to maintain a selective representation of traffic flows based on a few salient traffic features that point out to interesting events (e.g., potential conflicts). A field study is presented in this paper that examines salient features or 'knowledge variables' that constitute the building blocks of controller mental pictures. Verbal reports from participants, a field experiment and observations of real-life scenarios provided insights into the cognitive processes that shape and reframe the mental pictures of controllers. Several cognitive processes (i.e., problem detection, elaboration, reframing and replanning) have been explored within a particular framework of sensemaking stemming from the data/frame theory (Klein et al., 2007). Cognitive maps, representing standard and non-standard air traffic flows, emerged as an explanatory framework for making sense of traffic patterns and for reframing mental pictures. The data/frame theory proved to be a useful theoretical tool for investigating complex cognitive phenomena. The findings of the study have implications for the design of training curricula and decision support systems in air traffic control systems. Copyright © 2012 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Air traffic controller lightning strike.

PubMed Central

Spieth, M. E.; Kimura, R. L.; Schryer, T. D.

1994-01-01

Andersen Air Force Base in Guam boasts the tallest control tower in the Air Force. In 1986, an air traffic controller was struck by lightning as the bolt proceeded through the tower. Although he received only a backache, the lightning left a hole with surrounding scorch marks on his fatigue shirt and his undershirt. The lightning strike also ignited a portion of the field lighting panel, which caused the runway lights to go out immediately. Lack of a lightning rod is the most likely reason the controller was struck. Proper precautions against lightning strikes can prevent such occupational safety hazards. PMID:7966436

76 FR 46213 - National Standards for Traffic Control Devices; the Manual on Uniform Traffic Control Devices for...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-02

... design and application of traffic control devices, this Manual should not be considered a substitute for... retroreflectivity of longitudinal pavement markings. The deadline for comments to that docket has passed and the... the proposed revisions regarding maintaining minimum retroreflectivity of longitudinal pavement...

Work zone performance monitoring application development, research summary.

DOT National Transportation Integrated Search

2016-10-01

In 2004, the Federal Highway Administration (FHWA) updated the work zone regulations to encourage the collection and use of work zone safety and mobility data (23 CFR 630 Subpart J). The new rule essentially requires agencies to use data to generate ...

Developing traffic signal control systems using the national ITS architecture

DOT National Transportation Integrated Search

1998-02-01

This is one of a series of documents providing support for deploying Intelligent Transportation Systems (ITS). This document focuses on traffic signal control, a component of ITS. It aims to provide practical help for the traffic engineering communit...

Developing Traffic Signal Control Systems using the National ITS Architecture

DOT National Transportation Integrated Search

1998-02-01

This is one of a series of documents providing support for deploying Intelligent Transportation Systems (ITS). This document focuses on traffic signal control, a component of ITS. It aims to provide practical help for the traffic engineering communit...

78 FR 36132 - National Standards for Traffic Control Devices; Manual on Uniform Traffic Control Devices for...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-17

... traffic control devices used on all streets, highways, bikeways, and private roads open to public travel... restructuring the MUTCD into two documents at this time. FOR FURTHER INFORMATION CONTACT: For questions about... do this; however, it is unclear at this time where this material would be located. It could be...