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...

Summary Report: Uniform Traffic Control And Warning Messages For Portable Changeable Message Signs

DOT National Transportation Integrated Search

2000-03-01

The California database incorporated in the Highway Safety Information System (HSIS) is derived from the California TASAS (Traffic Accident Surveillance and Analysis System). The system, maintained by the Traffic Operations Office of Caltrans, is a m...

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 ...

23 CFR 655.604 - Achieving basic uniformity.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS TRAFFIC OPERATIONS Traffic Control Devices on Federal-Aid and Other Streets and Highways § 655.604... the Highway Safety Program Guideline 21, “Roadway Safety.” Highway planning and research funds and...

23 CFR 655.604 - Achieving basic uniformity.

Code of Federal Regulations, 2011 CFR

2011-04-01

... Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS TRAFFIC OPERATIONS Traffic Control Devices on Federal-Aid and Other Streets and Highways § 655.604... the Highway Safety Program Guideline 21, “Roadway Safety.” Highway planning and research funds and...

23 CFR 658.21 - Identification of National Network.

Code of Federal Regulations, 2012 CFR

2012-04-01

... the efficiency of the total traffic flow, such as time of day prohibitions, or lane use controls. (2....21 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC... National Network shall be signed. All signs shall conform to the Manual on Uniform Traffic Control Devices...

23 CFR 658.21 - Identification of National Network.

Code of Federal Regulations, 2013 CFR

2013-04-01

... the efficiency of the total traffic flow, such as time of day prohibitions, or lane use controls. (2....21 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC... National Network shall be signed. All signs shall conform to the Manual on Uniform Traffic Control Devices...

23 CFR 658.21 - Identification of National Network.

Code of Federal Regulations, 2014 CFR

2014-04-01

... the efficiency of the total traffic flow, such as time of day prohibitions, or lane use controls. (2....21 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC... National Network shall be signed. All signs shall conform to the Manual on Uniform Traffic Control Devices...

14 CFR Sec. 19-2 - Maintenance of data.

Code of Federal Regulations, 2011 CFR

2011-01-01

... operations are reported by the air carrier in operational control of the aircraft. The traffic moving under... shall maintain its operating statistics, covering the movement of traffic in accordance with the uniform classifications prescribed. Codes are prescribed for each operating element and service class. All traffic...

Uniform system of traffic guidance on European inland waterways : guidelines and criteria for vessel traffic service in inland waters

DOT National Transportation Integrated Search

2003-03-11

The International Maritime Organization (IMO) has developed guidelines on the principles and general operational provisions for the operation of a vessel traffic service (VTS).However, these guidelines only address seagoing vessels that have to compl...

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...

Retroreflectivity of existing signs in Pennsylvania.

DOT National Transportation Integrated Search

2012-04-01

The Pennsylvania Department of Transportation (PennDOT) Bureau of Highway Safety and Traffic Engineering initiated this : research effort in response to the release of the new 2009 Manual on Uniform Traffic Control Devices (MUTCD) which mandates : th...

Minimum sign retroreflective guidelines : summary report

DOT National Transportation Integrated Search

1997-06-01

Retroreflective traffic control devices are designed to help offset the lack of visual cues in the nighttime driving environment. Currently, the Manual on Uniform Traffic Control Devices requires that signs be retroreflectorized, but no minimum in-se...

2000 West Virginia accident data

DOT National Transportation Integrated Search

2000-01-01

The data contained within this report is extracted, by the : West Virginia Division of Highways, Traffic Engineering Division, from a database of : West Virginia Uniform Traffic Crash Reports submitted to the West Virginia Division of : Motor Vehicle...

2003 West Virginia crash data

DOT National Transportation Integrated Search

2003-01-01

This report was prepared by Traffic Engineering : personnel, from the West Virginia Division of Highways. The data contained in this : report is collected from Uniform Traffic Crash Reports submitted by state law : enforcement agencies. These law enf...

2002 West Virginia crash data

DOT National Transportation Integrated Search

2003-01-01

This report was prepared by Traffic Engineering : personnel, from the West Virginia Division of Highways. The data contained in this : report is collected from Uniform Traffic Crash Reports submitted by state law : enforcement agencies. These law enf...

A Global System for Transportation Simulation and Visualization in Emergency Evacuation Scenarios

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

Lu, Wei; Liu, Cheng; Thomas, Neil

2015-01-01

Simulation-based studies are frequently used for evacuation planning and decision making processes. Given the transportation systems complexity and data availability, most evacuation simulation models focus on certain geographic areas. With routine improvement of OpenStreetMap road networks and LandScanTM global population distribution data, we present WWEE, a uniform system for world-wide emergency evacuation simulations. WWEE uses unified data structure for simulation inputs. It also integrates a super-node trip distribution model as the default simulation parameter to improve the system computational performance. Two levels of visualization tools are implemented for evacuation performance analysis, including link-based macroscopic visualization and vehicle-based microscopic visualization. Formore » left-hand and right-hand traffic patterns in different countries, the authors propose a mirror technique to experiment with both scenarios without significantly changing traffic simulation models. Ten cities in US, Europe, Middle East, and Asia are modeled for demonstration. With default traffic simulation models for fast and easy-to-use evacuation estimation and visualization, WWEE also retains the capability of interactive operation for users to adopt customized traffic simulation models. For the first time, WWEE provides a unified platform for global evacuation researchers to estimate and visualize their strategies performance of transportation systems under evacuation scenarios.« less

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...

Light use study for vertical channelization devices

DOT National Transportation Integrated Search

2003-05-01

Although the Manual on Uniform Traffic Control Devices (MUTCD) does not require the use of warning lights on channelization devices, the Arizona Department of Transportation (ADOT) has historically required their use on all traffic control devices us...

2001 West Virginia crash data

DOT National Transportation Integrated Search

2001-01-01

This report was prepared by Traffic Engineering : personnel, from the West Virginia Division of Highways. The data contained in this : report is collected from Uniform Traffic Crash Reports submitted to the Division of : Motor Vehicles by state law e...

A decision support tool for selecting traffic control devices.

DOT National Transportation Integrated Search

2015-07-01

The Federal Highway Administration (FHWA) and transportation profession continue updating and : publishing the Manual on Uniform Traffic Control Devices (MUTCD). However, it is beyond the scope of : the MUTCD to provide the breadth of knowledge neces...

Valiant load-balanced robust routing under hose model for WDM mesh networks

NASA Astrophysics Data System (ADS)

Zhang, Xiaoning; Li, Lemin; Wang, Sheng

2006-09-01

In this paper, we propose Valiant Load-Balanced robust routing scheme for WDM mesh networks under the model of polyhedral uncertainty (i.e., hose model), and the proposed routing scheme is implemented with traffic grooming approach. Our Objective is to maximize the hose model throughput. A mathematic formulation of Valiant Load-Balanced robust routing is presented and three fast heuristic algorithms are also proposed. When implementing Valiant Load-Balanced robust routing scheme to WDM mesh networks, a novel traffic-grooming algorithm called MHF (minimizing hop first) is proposed. We compare the three heuristic algorithms with the VPN tree under the hose model. Finally we demonstrate in the simulation results that MHF with Valiant Load-Balanced robust routing scheme outperforms the traditional traffic-grooming algorithm in terms of the throughput for the uniform/non-uniform traffic matrix under the hose model.

14 CFR 137.45 - Nonobservance of airport traffic pattern.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Nonobservance of airport traffic pattern... AGRICULTURAL AIRCRAFT OPERATIONS Operating Rules § 137.45 Nonobservance of airport traffic pattern. Notwithstanding part 91 of this chapter, the pilot in command of an aircraft may deviate from an airport traffic...

14 CFR 137.45 - Nonobservance of airport traffic pattern.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Nonobservance of airport traffic pattern... AGRICULTURAL AIRCRAFT OPERATIONS Operating Rules § 137.45 Nonobservance of airport traffic pattern. Notwithstanding part 91 of this chapter, the pilot in command of an aircraft may deviate from an airport traffic...

14 CFR 137.45 - Nonobservance of airport traffic pattern.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Nonobservance of airport traffic pattern... AGRICULTURAL AIRCRAFT OPERATIONS Operating Rules § 137.45 Nonobservance of airport traffic pattern. Notwithstanding part 91 of this chapter, the pilot in command of an aircraft may deviate from an airport traffic...

14 CFR 137.45 - Nonobservance of airport traffic pattern.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Nonobservance of airport traffic pattern... AGRICULTURAL AIRCRAFT OPERATIONS Operating Rules § 137.45 Nonobservance of airport traffic pattern. Notwithstanding part 91 of this chapter, the pilot in command of an aircraft may deviate from an airport traffic...

14 CFR 137.45 - Nonobservance of airport traffic pattern.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Nonobservance of airport traffic pattern... AGRICULTURAL AIRCRAFT OPERATIONS Operating Rules § 137.45 Nonobservance of airport traffic pattern. Notwithstanding part 91 of this chapter, the pilot in command of an aircraft may deviate from an airport traffic...

A cellular automata model for traffic flow based on kinetics theory, vehicles capabilities and driver reactions

NASA Astrophysics Data System (ADS)

Guzmán, H. A.; Lárraga, M. E.; Alvarez-Icaza, L.; Carvajal, J.

2018-02-01

In this paper, a reliable cellular automata model oriented to faithfully reproduce deceleration and acceleration according to realistic reactions of drivers, when vehicles with different deceleration capabilities are considered is presented. The model focuses on describing complex traffic phenomena by coding in its rules the basic mechanisms of drivers behavior, vehicles capabilities and kinetics, while preserving simplicity. In particular, vehiclés kinetics is based on uniform accelerated motion, rather than in impulsive accelerated motion as in most existing CA models. Thus, the proposed model calculates in an analytic way three safe preserving distances to determine the best action a follower vehicle can take under a worst case scenario. Besides, the prediction analysis guarantees that under the proper assumptions, collision between vehicles may not happen at any future time. Simulations results indicate that all interactions of heterogeneous vehicles (i.e., car-truck, truck-car, car-car and truck-truck) are properly reproduced by the model. In addition, the model overcomes one of the major limitations of CA models for traffic modeling: the inability to perform smooth approach to slower or stopped vehicles. Moreover, the model is also capable of reproducing most empirical findings including the backward speed of the downstream front of the traffic jam, and different congested traffic patterns induced by a system with open boundary conditions with an on-ramp. Like most CA models, integer values are used to make the model run faster, which makes the proposed model suitable for real time traffic simulation of large networks.

Impacts of moving bottlenecks on traffic flow

NASA Astrophysics Data System (ADS)

Ou, Hui; Tang, Tie-Qiao

2018-06-01

Bottleneck (especially the moving bottleneck) widely exists in the urban traffic system. However, little effort has been made to study the impacts of the moving bottleneck on traffic flow (especially the evolution and propagation of traffic flow). In this article, we introduce the speed of a moving bottleneck into a traffic flow model, then propose an extended macro traffic flow with a moving bottleneck, and finally use the proposed model to study the effects of a moving bottleneck on the evolution and propagation of traffic flow under uniform flow and a small perturbation. The numerical results indicate that the moving bottleneck has prominent influences on the evolution of traffic flow under the two typical traffic situations and that the impacts are dependent on the initial density.

23 CFR 655.604 - Achieving basic uniformity.

Code of Federal Regulations, 2012 CFR

2012-04-01

... Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS... system should be based on inventories made in accordance with the Highway Safety Program Guideline 21, “Roadway Safety.” These inventories provide the information necessary for programming traffic control...

Implementation Guide for Minimum Retroreflectivity Requirements for Traffic Signs

DOT National Transportation Integrated Search

1998-04-01

Although the "Manual on Uniform Traffic Control Devices" (MUTCD) stipulates that all warning and regulatory signs be illuminated or reflectorized to show the same color and shape by day or night, there are no specific guidelines for required retroref...

Uniform Traffic Control and Warning Messages for Portable Changeable Message Signs

DOT National Transportation Integrated Search

1996-03-01

The purpose of this study was to develop and test word and symbol traffic control and hazard warning messages for use on portable changeable message signs (PCMSs). The literature was reviewed, State highway engineers were interviewed, PCMS manufactur...

Traffic control and work zone safety for high volume roads.

DOT National Transportation Integrated Search

2012-07-01

The Manual on Uniform Traffic Control Devices (MUTCD) predominantly addresses work performed : along the centerline of roadways and low-speed roads. This work does not apply to the majority of : situations encountered by New Jersey Department of Tran...

Temporary traffic control handbook for local agencies : tech transfer summary.

DOT National Transportation Integrated Search

2016-03-01

The updated handbook provides local agencies with uniform standards for temporary traffic control. The handbook includes sample layouts that can be used on various projects. Having sample layouts will provide a cost savings to agencies because the de...

A Cooperative V2V Alert System to Mitigate Vehicular Traffic ShockWaves

DOT National Transportation Integrated Search

2017-03-01

Vehicle traffic on highway systems are typically not uniformly distributed. In our work, we introduce a protocol that exploits this phenomenon by considering the formations of shock waves and opportunities in adjacent lanes. The objective of this pro...

Evaluation of work zone split traffic symbol sign : final report.

DOT National Transportation Integrated Search

2017-08-01

Effective signage that is easy to understand facilitates safe driving through a work zone. While the guidance for work zone signage in the Manual on Uniform Traffic Control Devices (MUTCD) is suitable for many conditions, there may be instances where...

The pedestrian in the transportation system : proposed traffic safety legislation.

DOT National Transportation Integrated Search

1981-01-01

The purposes of this project were to review and evaluate Virginia's traffic laws related to pedestrians, compare provisions of the Code of Virginia with those of the statutes of other states and the Uniform Vehicle Code, and, if appropriate, propose ...

Spatial distribution of traffic in a cellular mobile data network

NASA Astrophysics Data System (ADS)

Linnartz, J. P. M. G.

1987-02-01

The use of integral transforms of the probability density function for the received power to analyze the relation between the spatial distributions of offered and throughout packet traffic in a mobile radio network with Rayleigh fading channels and ALOHA multiple access was assessed. A method to obtain the spatial distribution of throughput traffic from a prescribed spatial distribution of offered traffic is presented. Incoherent and coherent addition of interference signals is considered. The channel behavior for heavy traffic loads is studied. In both the incoherent and coherent case, the spatial distribution of offered traffic required to ensure a prescribed spatially uniform throughput is synthesized numerically.

Transition Characteristic Analysis of Traffic Evolution Process for Urban Traffic Network

PubMed Central

Chen, Hong; Li, Yang

2014-01-01

The characterization of the dynamics of traffic states remains fundamental to seeking for the solutions of diverse traffic problems. To gain more insights into traffic dynamics in the temporal domain, this paper explored temporal characteristics and distinct regularity in the traffic evolution process of urban traffic network. We defined traffic state pattern through clustering multidimensional traffic time series using self-organizing maps and construct a pattern transition network model that is appropriate for representing and analyzing the evolution progress. The methodology is illustrated by an application to data flow rate of multiple road sections from Network of Shenzhen's Nanshan District, China. Analysis and numerical results demonstrated that the methodology permits extracting many useful traffic transition characteristics including stability, preference, activity, and attractiveness. In addition, more information about the relationships between these characteristics was extracted, which should be helpful in understanding the complex behavior of the temporal evolution features of traffic patterns. PMID:24982969

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...

Effects of traffic generation patterns on the robustness of complex networks

NASA Astrophysics Data System (ADS)

Wu, Jiajing; Zeng, Junwen; Chen, Zhenhao; Tse, Chi K.; Chen, Bokui

2018-02-01

Cascading failures in communication networks with heterogeneous node functions are studied in this paper. In such networks, the traffic dynamics are highly dependent on the traffic generation patterns which are in turn determined by the locations of the hosts. The data-packet traffic model is applied to Barabási-Albert scale-free networks to study the cascading failures in such networks and to explore the effects of traffic generation patterns on network robustness. It is found that placing the hosts at high-degree nodes in a network can make the network more robust against both intentional attacks and random failures. It is also shown that the traffic generation pattern plays an important role in network design.

Influence of local parameters on the dispersion of traffic-related pollutants within street canyons

NASA Astrophysics Data System (ADS)

Karra, Styliani; Malki-Epshtein, Liora; Martin Hyde Collaboration

2011-11-01

Ventilation within urban cities and street canyons and the associated air quality is a problem of increasing interest in the last decades. It is important for to minimise exposure of the population to traffic-related pollutants at street level. The residence time of pollutants within the street canyons depends on the meteorological conditions such as wind speed and direction, geometry layout and local parameters (position of traffic lane within the street). An experimental study was carried out to investigate the influence of traffic lane position on the dispersion of traffic-related pollutants within different street canyons geometries: symmetrical (equal building heights on both sides of the street), non-symmetrical (uniform building heights but lower on one side of the street) and heterogeneous (non-uniform building heights on both sides of the street) under constant meteorological conditions. Laboratory experiments were carried out within a water channel and simultaneous measurements of velocity field and concentration scalar levels within and above the street canyons using PIV and PLIF techniques. Traffic -related emissions were simulated using a line emission source. Two positions were examined for all street geometries: line emission source was placed in the centre of the street canyon; line emission source was placed off the centre of the street. TSI Incorporated.

Multistage switching hardware and software implementations for student experiment purpose

NASA Astrophysics Data System (ADS)

Sani, A.; Suherman

2018-02-01

Current communication and internet networks are underpinned by the switching technologies that interconnect one network to the others. Students’ understanding on networks rely on how they conver the theories. However, understanding theories without touching the reality may exert spots in the overall knowledge. This paper reports the progress of the multistage switching design and implementation for student laboratory activities. The hardware and software designs are based on three stages clos switching architecture with modular 2x2 switches, controlled by an arduino microcontroller. The designed modules can also be extended for batcher and bayan switch, and working on circuit and packet switching systems. The circuit analysis and simulation show that the blocking probability for each switch combinations can be obtained by generating random or patterned traffics. The mathematic model and simulation analysis shows 16.4% blocking probability differences as the traffic generation is uniform. The circuits design components and interfacing solution have been identified to allow next step implementation.

15 CFR 265.16 - Parking.

Code of Federal Regulations, 2010 CFR

2010-01-01

... GOVERNING TRAFFIC AND CONDUCT ON THE GROUNDS OF THE NATIONAL INSTITUTE OF STANDARDS & TECHNOLOGY... Parking. No person, unless otherwise authorized by a posted traffic sign or directed by a uniformed guard, shall stand or park a motor vehicle: (a) On a sidewalk; (b) Within an intersection or within a crosswalk...

15 CFR 265.16 - Parking.

Code of Federal Regulations, 2011 CFR

2011-01-01

... GOVERNING TRAFFIC AND CONDUCT ON THE GROUNDS OF THE NATIONAL INSTITUTE OF STANDARDS & TECHNOLOGY... Parking. No person, unless otherwise authorized by a posted traffic sign or directed by a uniformed guard, shall stand or park a motor vehicle: (a) On a sidewalk; (b) Within an intersection or within a crosswalk...

Safety performance testing of a modified Oregon multidirectional slip-base sign support : FOIL test numbers 98F002 and 98F004

DOT National Transportation Integrated Search

1997-07-01

This project evaluated the effectiveness of symbol traffic signs for young, middle-aged and elderly drivers. Daytime legibility distance and comprehension of 85 symbols in the Manual on Uniform Traffic Control Devices (MUTCD) were measured. Legibilit...

Differential prediction of FAA Academy performance on the basis of gender and written air traffic control specialist aptitude test scores.

DOT National Transportation Integrated Search

1996-04-01

The technical fairness of the written air traffic control specialist (ATCS) aptitude test battery was investigated within the framework of the Uniform Guidelines on Employee Selection Procedures (29 CFR 1607). First, the adverse impact of using a com...

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 ...

14 CFR 25 - Traffic and Capacity Elements

Code of Federal Regulations, 2012 CFR

2012-01-01

... PROCEEDINGS) ECONOMIC REGULATIONS UNIFORM SYSTEM OF ACCOUNTS AND REPORTS FOR LARGE CERTIFICATED AIR CARRIERS... forth in section 19—Uniform Classification of Operating Statistics. (b) Carriers submitting Schedule T-100 shall use magnetic computer tape or IBM compatible disk for transmitting the prescribed data to...

14 CFR Section 25 - Traffic and Capacity Elements

Code of Federal Regulations, 2013 CFR

2013-01-01

... PROCEEDINGS) ECONOMIC REGULATIONS UNIFORM SYSTEM OF ACCOUNTS AND REPORTS FOR LARGE CERTIFICATED AIR CARRIERS... forth in section 19—Uniform Classification of Operating Statistics. (b) Carriers submitting Schedule T-100 shall use magnetic computer tape or IBM compatible disk for transmitting the prescribed data to...

General aviation air traffic pattern safety analysis

NASA Technical Reports Server (NTRS)

Parker, L. C.

1973-01-01

A concept is described for evaluating the general aviation mid-air collision hazard in uncontrolled terminal airspace. Three-dimensional traffic pattern measurements were conducted at uncontrolled and controlled airports. Computer programs for data reduction, storage retrieval and statistical analysis have been developed. Initial general aviation air traffic pattern characteristics are presented. These preliminary results indicate that patterns are highly divergent from the expected standard pattern, and that pattern procedures observed can affect the ability of pilots to see and avoid each other.

Exploratory statistical and geographical freight traffic data analysis

DOT National Transportation Integrated Search

2000-08-01

Data from freight traffic roadside surveys in Mexican highways are analyzed in order to find consistent patterns or systematic relationships between variables characterizing this traffic. Patterns traced are validated by contrasting against new data ...

Efficient packet transportation on complex networks with nonuniform node capacity distribution

NASA Astrophysics Data System (ADS)

He, Xuan; Niu, Kai; He, Zhiqiang; Lin, Jiaru; Jiang, Zhong-Yuan

2015-03-01

Provided that node delivery capacity may be not uniformly distributed in many realistic networks, we present a node delivery capacity distribution in which each node capacity is composed of uniform fraction and degree related proportion. Based on the node delivery capacity distribution, we construct a novel routing mechanism called efficient weighted routing (EWR) strategy to enhance network traffic capacity and transportation efficiency. Compared with the shortest path routing and the efficient routing strategies, the EWR achieves the highest traffic capacity. After investigating average path length, network diameter, maximum efficient betweenness, average efficient betweenness, average travel time and average traffic load under extensive simulations, it indicates that the EWR appears to be a very effective routing method. The idea of this routing mechanism gives us a good insight into network science research. The practical use of this work is prospective in some real complex systems such as the Internet.

75 FR 20935 - National Standards for Traffic Control Devices; the Manual on Uniform Traffic Control Devices for...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-22

... for implementation and continued use of a maintenance method that is designed to maintain pavement... method that is designed to maintain pavement marking retroreflectivity at or above the established levels... every pavement marking in its jurisdiction. Instead, agencies must implement methods designed to provide...

Modeling left-turn crash occurrence at signalized intersections by conflicting patterns.

PubMed

Wang, Xuesong; Abdel-Aty, Mohamed

2008-01-01

In order to better understand the underlying crash mechanisms, left-turn crashes occurring at 197 four-legged signalized intersections over 6 years were classified into nine patterns based on vehicle maneuvers and then were assigned to intersection approaches. Crash frequency of each pattern was modeled at the approach level by mainly using Generalized Estimating Equations (GEE) with the Negative Binomial as the link function to account for the correlation among the crash data. GEE with a binomial logit link function was also applied for patterns with fewer crashes. The Cumulative Residuals test shows that, for correlated left-turn crashes, GEE models usually outperformed basic Negative Binomial models. The estimation results show that there are obvious differences in the factors that cause the occurrence of different left-turn collision patterns. For example, for each pattern, the traffic flows to which the colliding vehicles belong are identified to be significant. The width of the crossing distance (represented by the number of through lanes on the opposing approach of the left-turning traffic) is associated with more left-turn traffic colliding with opposing through traffic (Pattern 5), but with less left-turning traffic colliding with near-side crossing through traffic (Pattern 8). The safety effectiveness of the left-turning signal is not consistent for different crash patterns; "protected" phasing is correlated with fewer Pattern 5 crashes, but with more Pattern 8 crashes. The study indicates that in order to develop efficient countermeasures for left-turn crashes and improve safety at signalized intersections, left-turn crashes should be considered in different patterns.

Non-Uniform Per-Packet Priority Marker for Use with Adaptive Protocols

DTIC Science & Technology

2014-01-07

through con­ gestion points that would totally stop traffic from a customer using the SLA shown in FIG. 5, though only some fraction of his traffic...assigning priori­ ties to TCP flows. PDQoS has potential to fill the need for a quality of service mechanism that is simple to configure and to

78 FR 2347 - National Standards for Traffic Control Devices; the Manual on Uniform Traffic Control Devices for...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-11

... rulemaking. This document asks for responses to a series of questions regarding formats, types of material to... the types of material that could potentially be moved from the MUTCD to the Applications Supplement... seeks input on the type of material to be included in the MUTCD and the Applications Supplement, as well...

Satellite economics in the 1980's

NASA Astrophysics Data System (ADS)

Morgan, W. L.

1980-01-01

Satellite traffic, competition, and decreasing costs are discussed, as are capabilities in telecommunication (including entertainment) and computation. Also considered are future teleconferencing and telecommuting to offset the cost of transportation, the establishment of a manufacturer-to-user link for increased home minicomputer capability, and an increase of digital over analog traffic. It is suggested that transcontinental bulk traffic, high-speed data, and multipoint private networks will eventually be handled by satellites which are cost-insensitive to distance, readily match dynamically varying multipoint networks, and have uniformly wide bandwidths available to both major cities and isolated towns.

Nonuniform traffic spots (NUTS) in multistage interconnection networks

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

Lang, T.; Kurisaki, L.

1990-09-01

The performance of multistage interconnection networks for multiprocessors is degraded when the traffic pattern produces nonuniform congestion in the blocking switches, that is, when there exist nonuniform traffic spots. For some specific patterns the authors evaluate this degradation in performance and propose modifications to the network organization and operation to reduce the degradation. Successful modifications are the use of diverting switches and the extension of the network with additional links. The use of these modifications makes the network more effective for a larger variety of traffic patterns. The authors also consider the case in which the network carries the superpositionmore » of two types of traffic. One type is the high throughput data and instruction traffic, while the other consists of control and I/O packets which are of low throughput but have severe real-time constraints. The authors conclude that diverting switches and networks with additional links are also suitable for assuring low latency for the real-time traffic, especially when using the displacing mode.« less

Global Simulation of Aviation Operations

NASA Technical Reports Server (NTRS)

Sridhar, Banavar; Sheth, Kapil; Ng, Hok Kwan; Morando, Alex; Li, Jinhua

2016-01-01

The simulation and analysis of global air traffic is limited due to a lack of simulation tools and the difficulty in accessing data sources. This paper provides a global simulation of aviation operations combining flight plans and real air traffic data with historical commercial city-pair aircraft type and schedule data and global atmospheric data. The resulting capability extends the simulation and optimization functions of NASA's Future Air Traffic Management Concept Evaluation Tool (FACET) to global scale. This new capability is used to present results on the evolution of global air traffic patterns from a concentration of traffic inside US, Europe and across the Atlantic Ocean to a more diverse traffic pattern across the globe with accelerated growth in Asia, Australia, Africa and South America. The simulation analyzes seasonal variation in the long-haul wind-optimal traffic patterns in six major regions of the world and provides potential time-savings of wind-optimal routes compared with either great circle routes or current flight-plans if available.

Studies of uncontrolled air traffic patterns, phase 1

NASA Technical Reports Server (NTRS)

Baxa, E. G., Jr.; Scharf, L. L.; Ruedger, W. H.; Modi, J. A.; Wheelock, S. L.; Davis, C. M.

1975-01-01

The general aviation air traffic flow patterns at uncontrolled airports are investigated and analyzed and traffic pattern concepts are developed to minimize the midair collision hazard in uncontrolled airspace. An analytical approach to evaluate midair collision hazard probability as a function of traffic densities is established which is basically independent of path structure. Two methods of generating space-time interrelationships between terminal area aircraft are presented; one is a deterministic model to generate pseudorandom aircraft tracks, the other is a statistical model in preliminary form. Some hazard measures are presented for selected traffic densities. It is concluded that the probability of encountering a hazard should be minimized independently of any other considerations and that the number of encounters involving visible-avoidable aircraft should be maximized at the expense of encounters in other categories.

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.

Open-Source Data Collection Techniques for Weapons Transfer Information

DTIC Science & Technology

2012-03-01

IR Infrared ISO International Organization for Standardization ITAR International Traffic in Arms Regulations NER Named Entity Recognition NLP ...Control Protocol UAE United Arab Emirates URI Uniform Resource Identifier URL Uniform Resource Locator USSR Union of Soviet Socialist Republics UTF...KOREA, DEMOCRATIC PEOPLE’S REPUBLIC OF North Korea KOREA, REPUBLIC OF South Korea LIBYAN ARAB JAMAHIRIYA Libya RUSSIAN FEDERATION Russia Table 3

Network-constrained spatio-temporal clustering analysis of traffic collisions in Jianghan District of Wuhan, China

PubMed Central

Fan, Yaxin; Zhu, Xinyan; Guo, Wei; Guo, Tao

2018-01-01

The analysis of traffic collisions is essential for urban safety and the sustainable development of the urban environment. Reducing the road traffic injuries and the financial losses caused by collisions is the most important goal of traffic management. In addition, traffic collisions are a major cause of traffic congestion, which is a serious issue that affects everyone in the society. Therefore, traffic collision analysis is essential for all parties, including drivers, pedestrians, and traffic officers, to understand the road risks at a finer spatio-temporal scale. However, traffic collisions in the urban context are dynamic and complex. Thus, it is important to detect how the collision hotspots evolve over time through spatio-temporal clustering analysis. In addition, traffic collisions are not isolated events in space. The characteristics of the traffic collisions and their surrounding locations also present an influence of the clusters. This work tries to explore the spatio-temporal clustering patterns of traffic collisions by combining a set of network-constrained methods. These methods were tested using the traffic collision data in Jianghan District of Wuhan, China. The results demonstrated that these methods offer different perspectives of the spatio-temporal clustering patterns. The weighted network kernel density estimation provides an intuitive way to incorporate attribute information. The network cross K-function shows that there are varying clustering tendencies between traffic collisions and different types of POIs. The proposed network differential Local Moran’s I and network local indicators of mobility association provide straightforward and quantitative measures of the hotspot changes. This case study shows that these methods could help researchers, practitioners, and policy-makers to better understand the spatio-temporal clustering patterns of traffic collisions. PMID:29672551

Analysis of energy consumption and emission of the heterogeneous traffic flow consisting of traditional vehicles and electric vehicles

NASA Astrophysics Data System (ADS)

Xiao, Hong; Huang, Hai-Jun; Tang, Tie-Qiao

2017-12-01

Electric vehicle (EV) has become a potential traffic tool, which has attracted researchers to explore various traffic phenomena caused by EV (e.g. congestion, electricity consumption, etc.). In this paper, we study the energy consumption (including the fuel consumption and the electricity consumption) and emissions of heterogeneous traffic flow (that consists of the traditional vehicle (TV) and EV) under three traffic situations (i.e. uniform flow, shock and rarefaction waves, and a small perturbation) from the perspective of macro traffic flow. The numerical results show that the proportion of electric vehicular flow has great effects on the TV’s fuel consumption and emissions and the EV’s electricity consumption, i.e. the fuel consumption and emissions decrease while the electricity consumption increases with the increase of the proportion of electric vehicular flow. The results can help us better understand the energy consumption and emissions of the heterogeneous traffic flow consisting of TV and EV.

Analysis of traffic growth rates

DOT National Transportation Integrated Search

2001-08-01

The primary objectives of this study were to determine patterns of traffic flow and develop traffic growth rates by traffic composition and highway type for Kentucky's system of highways. Additional subtasks included the following: 1) a literature se...

Collective Human Mobility Pattern from Taxi Trips in Urban Area

PubMed Central

Peng, Chengbin; Jin, Xiaogang; Wong, Ka-Chun; Shi, Meixia; Liò, Pietro

2012-01-01

We analyze the passengers' traffic pattern for 1.58 million taxi trips of Shanghai, China. By employing the non-negative matrix factorization and optimization methods, we find that, people travel on workdays mainly for three purposes: commuting between home and workplace, traveling from workplace to workplace, and others such as leisure activities. Therefore, traffic flow in one area or between any pair of locations can be approximated by a linear combination of three basis flows, corresponding to the three purposes respectively. We name the coefficients in the linear combination as traffic powers, each of which indicates the strength of each basis flow. The traffic powers on different days are typically different even for the same location, due to the uncertainty of the human motion. Therefore, we provide a probability distribution function for the relative deviation of the traffic power. This distribution function is in terms of a series of functions for normalized binomial distributions. It can be well explained by statistical theories and is verified by empirical data. These findings are applicable in predicting the road traffic, tracing the traffic pattern and diagnosing the traffic related abnormal events. These results can also be used to infer land uses of urban area quite parsimoniously. PMID:22529917

Pilot scanning patterns while viewing cockpit displays of traffic information

NASA Technical Reports Server (NTRS)

Ellis, S. R.; Stark, L.

1981-01-01

Scanning eye movements of airline pilots were recorded while they judged air traffic situations displayed on cockpit displays of traffic information (CDTI). The observed 1st order transition patterns between points of interest on the display showed reliable deviation from those patterns predicted by the assumption of statistical independence. However, both patterns of transitions correlated quite well with each other. Accordingly, the assumption of independence provided a surprisingly good model of the results. Nevertheless, the deviation between the observed patterns of transition and that based on the assumption of independence was for all subjects in the direction of increased determinism. Thus, the results provide objective evidence consistent with the existence of "scanpaths" in the data.

The impact of traffic-flow patterns on air quality in urban street canyons.

PubMed

Thaker, Prashant; Gokhale, Sharad

2016-01-01

We investigated the effect of different urban traffic-flow patterns on pollutant dispersion in different winds in a real asymmetric street canyon. Free-flow traffic causes more turbulence in the canyon facilitating more dispersion and a reduction in pedestrian level concentration. The comparison of with and without a vehicle-induced-turbulence revealed that when winds were perpendicular, the free-flow traffic reduced the concentration by 73% on the windward side with a minor increase of 17% on the leeward side, whereas for parallel winds, it reduced the concentration by 51% and 29%. The congested-flow traffic increased the concentrations on the leeward side by 47% when winds were perpendicular posing a higher risk to health, whereas reduced it by 17-42% for parallel winds. The urban air quality and public health can, therefore, be improved by improving the traffic-flow patterns in street canyons as vehicle-induced turbulence has been shown to contribute significantly to dispersion. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fast traffic sign recognition with a rotation invariant binary pattern based feature.

PubMed

Yin, Shouyi; Ouyang, Peng; Liu, Leibo; Guo, Yike; Wei, Shaojun

2015-01-19

Robust and fast traffic sign recognition is very important but difficult for safe driving assistance systems. This study addresses fast and robust traffic sign recognition to enhance driving safety. The proposed method includes three stages. First, a typical Hough transformation is adopted to implement coarse-grained location of the candidate regions of traffic signs. Second, a RIBP (Rotation Invariant Binary Pattern) based feature in the affine and Gaussian space is proposed to reduce the time of traffic sign detection and achieve robust traffic sign detection in terms of scale, rotation, and illumination. Third, the techniques of ANN (Artificial Neutral Network) based feature dimension reduction and classification are designed to reduce the traffic sign recognition time. Compared with the current work, the experimental results in the public datasets show that this work achieves robustness in traffic sign recognition with comparable recognition accuracy and faster processing speed, including training speed and recognition speed.

Traffic experiment reveals the nature of car-following.

PubMed

Jiang, Rui; Hu, Mao-Bin; Zhang, H M; Gao, Zi-You; Jia, Bin; Wu, Qing-Song; Wang, Bing; Yang, Ming

2014-01-01

As a typical self-driven many-particle system far from equilibrium, traffic flow exhibits diverse fascinating non-equilibrium phenomena, most of which are closely related to traffic flow stability and specifically the growth/dissipation pattern of disturbances. However, the traffic theories have been controversial due to a lack of precise traffic data. We have studied traffic flow from a new perspective by carrying out large-scale car-following experiment on an open road section, which overcomes the intrinsic deficiency of empirical observations. The experiment has shown clearly the nature of car-following, which runs against the traditional traffic flow theory. Simulations show that by removing the fundamental notion in the traditional car-following models and allowing the traffic state to span a two-dimensional region in velocity-spacing plane, the growth pattern of disturbances has changed qualitatively and becomes qualitatively or even quantitatively in consistent with that observed in the experiment.

Traffic Experiment Reveals the Nature of Car-Following

PubMed Central

Jiang, Rui; Hu, Mao-Bin; Zhang, H. M.; Gao, Zi-You; Jia, Bin; Wu, Qing-Song; Wang, Bing; Yang, Ming

2014-01-01

As a typical self-driven many-particle system far from equilibrium, traffic flow exhibits diverse fascinating non-equilibrium phenomena, most of which are closely related to traffic flow stability and specifically the growth/dissipation pattern of disturbances. However, the traffic theories have been controversial due to a lack of precise traffic data. We have studied traffic flow from a new perspective by carrying out large-scale car-following experiment on an open road section, which overcomes the intrinsic deficiency of empirical observations. The experiment has shown clearly the nature of car-following, which runs against the traditional traffic flow theory. Simulations show that by removing the fundamental notion in the traditional car-following models and allowing the traffic state to span a two-dimensional region in velocity-spacing plane, the growth pattern of disturbances has changed qualitatively and becomes qualitatively or even quantitatively in consistent with that observed in the experiment. PMID:24740284

Fast Traffic Sign Recognition with a Rotation Invariant Binary Pattern Based Feature

PubMed Central

Yin, Shouyi; Ouyang, Peng; Liu, Leibo; Guo, Yike; Wei, Shaojun

2015-01-01

Robust and fast traffic sign recognition is very important but difficult for safe driving assistance systems. This study addresses fast and robust traffic sign recognition to enhance driving safety. The proposed method includes three stages. First, a typical Hough transformation is adopted to implement coarse-grained location of the candidate regions of traffic signs. Second, a RIBP (Rotation Invariant Binary Pattern) based feature in the affine and Gaussian space is proposed to reduce the time of traffic sign detection and achieve robust traffic sign detection in terms of scale, rotation, and illumination. Third, the techniques of ANN (Artificial Neutral Network) based feature dimension reduction and classification are designed to reduce the traffic sign recognition time. Compared with the current work, the experimental results in the public datasets show that this work achieves robustness in traffic sign recognition with comparable recognition accuracy and faster processing speed, including training speed and recognition speed. PMID:25608217

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, ...

Nurses' uniform color and feelings/emotions in school-aged children receiving health care.

PubMed

Albert, Nancy M; Burke, Jane; Bena, James F; Morrison, Shannon M; Forney, Jennifer; Krajewski, Susan

2013-04-01

Children may fear nurses wearing white uniforms. When emotions and uniform color were studied in 233 children, many positive emotions were most often associated with blue, bold pink-patterned, or yellow-patterned tops (all p ≤ .002). Negative emotions were not associated with uniform top colors (all p < .001). However, after excluding "uniform color does not matter," 8 negative emotions were most often associated with white uniform color (p < .001-.04), and 2 others were most often associated with the yellow-patterned top. Bold pink-patterned and solid blue uniform tops were preferred. In conclusion, children's emotions were associated with nurse uniform color. Copyright © 2013 Elsevier Inc. All rights reserved.

14 CFR Sec. 19-6 - Public disclosure of traffic data.

Code of Federal Regulations, 2014 CFR

2014-01-01

... PROCEEDINGS) ECONOMIC REGULATIONS UNIFORM SYSTEM OF ACCOUNTS AND REPORTS FOR LARGE CERTIFICATED AIR CARRIERS..., shall be publicly available immediately following the Department's determination that the database is...

Characteristics of trace metals in traffic-derived particles in Hsuehshan Tunnel, Taiwan: size distribution, potential source, and fingerprinting metal ratio

NASA Astrophysics Data System (ADS)

Lin, Y.-C.; Tsai, C.-J.; Wu, Y.-C.; Zhang, R.; Chi, K.-H.; Huang, Y.-T.; Lin, S.-H.; Hsu, S.-C.

2015-04-01

Traffic emissions are a significant source of airborne particulate matter (PM) in ambient environments. These emissions contain an abundance of toxic metals and thus pose adverse effects on human health. Size-fractionated aerosol samples were collected from May to September 2013 by using micro-orifice uniform deposited impactors (MOUDIs). Sample collection was conducted simultaneously at the inlet and outlet sites of Hsuehshan Tunnel in northern Taiwan, which is the second-longest freeway tunnel (12.9 km) in Asia. This endeavor aims to characterize the chemical constituents and size distributions, as well as fingerprinting ratios of particulate metals emitted by vehicle fleets. A total of 36 metals in size-resolved aerosols were determined through inductively coupled plasma mass spectrometry. Three major groups - namely, tailpipe emissions (Zn, Pb, and V in fine mode), wear debris (Cu, Cd, Fe, Ga, Mn, Mo, Sb, and Sn), and resuspended dust (Ca, Mg, K, and Rb) - of airborne PM metals were categorized on the basis of the results of enrichment factor, correlation matrix, and principal component analysis. Size distributions of wear-originated metals resembled the pattern of crustal elements, which were predominated by super-micron particulates (PM1-10). By contrast, tailpipe exhaust elements such as Zn, Pb, and V were distributed mainly in submicron particles. By employing Cu as a tracer of wear abrasion, several inter-metal ratios - including Fe / Cu (14), Ba / Cu (1.05), Sb / Cu (0.16), Sn / Cu (0.10), and Ga / Cu (0.03) - served as fingerprints for wear debris. However, the data set collected in this work is useful for further studies on traffic emission inventory and human health effects of traffic-related PM.

A Study towards Building An Optimal Graph Theory Based Model For The Design of Tourism Website

NASA Astrophysics Data System (ADS)

Panigrahi, Goutam; Das, Anirban; Basu, Kajla

2010-10-01

Effective tourism website is a key to attract tourists from different parts of the world. Here we identify the factors of improving the effectiveness of website by considering it as a graph, where web pages including homepage are the nodes and hyperlinks are the edges between the nodes. In this model, the design constraints for building a tourism website are taken into consideration. Our objectives are to build a framework of an effective tourism website providing adequate level of information, service and also to enable the users to reach to the desired page by spending minimal loading time. In this paper an information hierarchy specifying the upper limit of outgoing link of a page has also been proposed. Following the hierarchy, the web developer can prepare an effective tourism website. Here loading time depends on page size and network traffic. We have assumed network traffic as uniform and the loading time is directly proportional with page size. This approach is done by quantifying the link structure of a tourism website. In this approach we also propose a page size distribution pattern of a tourism website.

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...

Predictability of Road Traffic and Congestion in Urban Areas

PubMed Central

Wang, Jingyuan; Mao, Yu; Li, Jing; Xiong, Zhang; Wang, Wen-Xu

2015-01-01

Mitigating traffic congestion on urban roads, with paramount importance in urban development and reduction of energy consumption and air pollution, depends on our ability to foresee road usage and traffic conditions pertaining to the collective behavior of drivers, raising a significant question: to what degree is road traffic predictable in urban areas? Here we rely on the precise records of daily vehicle mobility based on GPS positioning device installed in taxis to uncover the potential daily predictability of urban traffic patterns. Using the mapping from the degree of congestion on roads into a time series of symbols and measuring its entropy, we find a relatively high daily predictability of traffic conditions despite the absence of any priori knowledge of drivers' origins and destinations and quite different travel patterns between weekdays and weekends. Moreover, we find a counterintuitive dependence of the predictability on travel speed: the road segment associated with intermediate average travel speed is most difficult to be predicted. We also explore the possibility of recovering the traffic condition of an inaccessible segment from its adjacent segments with respect to limited observability. The highly predictable traffic patterns in spite of the heterogeneity of drivers' behaviors and the variability of their origins and destinations enables development of accurate predictive models for eventually devising practical strategies to mitigate urban road congestion. PMID:25849534

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...

Evaluation of Anomaly Detection Method Based on Pattern Recognition

NASA Astrophysics Data System (ADS)

Fontugne, Romain; Himura, Yosuke; Fukuda, Kensuke

The number of threats on the Internet is rapidly increasing, and anomaly detection has become of increasing importance. High-speed backbone traffic is particularly degraded, but their analysis is a complicated task due to the amount of data, the lack of payload data, the asymmetric routing and the use of sampling techniques. Most anomaly detection schemes focus on the statistical properties of network traffic and highlight anomalous traffic through their singularities. In this paper, we concentrate on unusual traffic distributions, which are easily identifiable in temporal-spatial space (e.g., time/address or port). We present an anomaly detection method that uses a pattern recognition technique to identify anomalies in pictures representing traffic. The main advantage of this method is its ability to detect attacks involving mice flows. We evaluate the parameter set and the effectiveness of this approach by analyzing six years of Internet traffic collected from a trans-Pacific link. We show several examples of detected anomalies and compare our results with those of two other methods. The comparison indicates that the only anomalies detected by the pattern-recognition-based method are mainly malicious traffic with a few packets.

Optimization and Calculation of Probability Performances of Processes of Storage and Processing of Refrigerator Containerized Cargoes

NASA Astrophysics Data System (ADS)

Nyrkov, A. P.; Sokolov, S. S.; Chernyi, S. G.; Shnurenko, A. A.; Pavlova, L. A.

2016-08-01

In the work the queueing system of the disconnected multi-channel type to which irregular, uniform or not uniform flows of requests with a unlimited latency period arrive is considered. The system is considered on an example of the container terminal having conditional-functional sections with a definite mark-to-space ratio on which the irregular inhomogeneous traffic flow with resultant intensity acts.

Evaluation of pavement marking performance.

DOT National Transportation Integrated Search

2008-06-01

The objective of the investigation was to evaluate the useful life of pavement markings. The Manual on Uniform Traffic Control Devices (MUTCD) provides general guidelines for the application and installation of pavement markings. However, performance...

14 CFR Section 19-6 - Public disclosure of traffic data.

Code of Federal Regulations, 2010 CFR

2010-01-01

... (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS UNIFORM SYSTEM OF ACCOUNTS AND REPORTS FOR LARGE CERTIFICATED... database is complete, but no earlier than six months after the date of the data. Military operations are...

14 CFR Section 19-6 - Public disclosure of traffic data.

Code of Federal Regulations, 2011 CFR

2011-01-01

... (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS UNIFORM SYSTEM OF ACCOUNTS AND REPORTS FOR LARGE CERTIFICATED... database is complete, but no earlier than six months after the date of the data. Military operations are...

14 CFR 19-6 - Public disclosure of traffic data.

Code of Federal Regulations, 2012 CFR

2012-01-01

... (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS UNIFORM SYSTEM OF ACCOUNTS AND REPORTS FOR LARGE CERTIFICATED... database is complete, but no earlier than six months after the date of the data. Military operations are...

14 CFR Section 19-6 - Public disclosure of traffic data.

Code of Federal Regulations, 2013 CFR

2013-01-01

... (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS UNIFORM SYSTEM OF ACCOUNTS AND REPORTS FOR LARGE CERTIFICATED... database is complete, but no earlier than six months after the date of the data. Military operations are...

49 CFR 382.103 - Applicability.

Code of Federal Regulations, 2012 CFR

2012-10-01

... who are required to wear military uniforms), and active duty U.S. Coast Guard personnel; or (3) Who a... governmental functions, are equipped with audible and visual signals, and are not subject to normal traffic...

49 CFR 382.103 - Applicability.

Code of Federal Regulations, 2011 CFR

2011-10-01

... who are required to wear military uniforms), and active duty U.S. Coast Guard personnel; or (3) Who a... governmental functions, are equipped with audible and visual signals, and are not subject to normal traffic...

49 CFR 382.103 - Applicability.

Code of Federal Regulations, 2014 CFR

2014-10-01

... who are required to wear military uniforms), and active duty U.S. Coast Guard personnel; or (3) Who a... governmental functions, are equipped with audible and visual signals, and are not subject to normal traffic...

49 CFR 382.103 - Applicability.

Code of Federal Regulations, 2013 CFR

2013-10-01

... who are required to wear military uniforms), and active duty U.S. Coast Guard personnel; or (3) Who a... governmental functions, are equipped with audible and visual signals, and are not subject to normal traffic...

49 CFR 382.103 - Applicability.

Code of Federal Regulations, 2010 CFR

2010-10-01

... who are required to wear military uniforms), and active duty U.S. Coast Guard personnel; or (3) Who a... governmental functions, are equipped with audible and visual signals, and are not subject to normal traffic...

High-occupancy vehicle guidelines for planning, design and operations

DOT National Transportation Integrated Search

2003-08-01

These guidelines are not intended to supersede Caltrans : Transportation Planning Manual, Project Development : Procedures Manual, Highway Design Manual, Manual : on Uniform Traffic Control Devices (MUTCD) and : California Supplement to the MUTCD ...

Emergency medical dispatch : national standard curriculum ready

DOT National Transportation Integrated Search

1996-05-01

This Traffic Tech describes the recently updated "Emergency Medical Dispatch: National Standard Curriculum," which was developed in 1972. Emergency service providers use these uniform standards to develop or select an emergency medical dispatch progr...

Variability of particulate matter concentrations along roads and motorways determined by a moving measurement unit

NASA Astrophysics Data System (ADS)

Weijers, E. P.; Khlystov, A. Y.; Kos, G. P. A.; Erisman, J. W.

The spatial variability of aerosol number and mass along roads was determined in different regions (urban, rural and coastal-marine) of the Netherlands. A condensation particle counter (CPC) and an optical aerosol spectrometer (LAS-X) were installed in a van along with a global positioning system (GPS). Concentrations were measured with high-time resolutions while driving allowing investigations not possible with stationary equipment. In particular, this approach proves to be useful to identify those locations where numbers and mass attain high levels ('hot spots'). In general, concentrations of number and mass of particulate matter increase along with the degree of urbanisation, with number concentration being the more sensitive indicator. The lowest particle numbers and PM 1-concentrations are encountered in a coastal and rural area: <5000 cm -3 and 6 μg m -3, respectively. The presence of sea-salt material along the North-Sea coast enhances PM >1-concentrations compared to inland levels. High-particle numbers are encountered on motorways correlating with traffic intensity; the largest average number concentration is measured on the ring motorway around Amsterdam: about 160 000 cm -3 (traffic intensity 100 000 veh day -1). Peak values occur in tunnels where numbers exceed 10 6 cm -3. Enhanced PM 1 levels (i.e. larger than 9 μg m -3) exist on motorways, major traffic roads and in tunnels. The concentrations of PM >1 appear rather uniformly distributed (below 6 μg m -3 for most observations). On the urban scale, (large) spatial variations in concentration can be explained by varying intensities of traffic and driving patterns. The highest particle numbers are measured while being in traffic congestions or when behind a heavy diesel-driven vehicle (up to 600×10 3 cm -3). Relatively high numbers are observed during the passages of crossings and, at a decreasing rate, on main roads with much traffic, quiet streets and residential areas with limited traffic. The number concentration exhibits a larger variability than mass: the mass concentration on city roads with much traffic is 12% higher than in a residential area at the edge of the same city while the number of particles changes by a factor of two (due to the presence of the ultrafine particles (aerodynamic diameter <100 nm). It is further indicated that people residing at some 100 m downwind a major traffic source are exposed to (still) 40% more particles than those living in the urban background areas.

14 CFR 93.67 - General rules: Bryant segment.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Airport shall conform to the flow of traffic shown on the appropriate aeronautical charts, and while in the traffic pattern, shall operate that airplane at an altitude of at least 1,000 feet MSL until... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Anchorage, Alaska, Terminal...

14 CFR 93.67 - General rules: Bryant segment.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Airport shall conform to the flow of traffic shown on the appropriate aeronautical charts, and while in the traffic pattern, shall operate that airplane at an altitude of at least 1,000 feet MSL until... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Anchorage, Alaska, Terminal...

14 CFR 93.67 - General rules: Bryant segment.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Airport shall conform to the flow of traffic shown on the appropriate aeronautical charts, and while in the traffic pattern, shall operate that airplane at an altitude of at least 1,000 feet MSL until... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Anchorage, Alaska, Terminal...

14 CFR 93.67 - General rules: Bryant segment.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Airport shall conform to the flow of traffic shown on the appropriate aeronautical charts, and while in the traffic pattern, shall operate that airplane at an altitude of at least 1,000 feet MSL until... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Anchorage, Alaska, Terminal...

A Wavelet Analysis Approach for Categorizing Air Traffic Behavior

NASA Technical Reports Server (NTRS)

Drew, Michael; Sheth, Kapil

2015-01-01

In this paper two frequency domain techniques are applied to air traffic analysis. The Continuous Wavelet Transform (CWT), like the Fourier Transform, is shown to identify changes in historical traffic patterns caused by Traffic Management Initiatives (TMIs) and weather with the added benefit of detecting when in time those changes take place. Next, with the expectation that it could detect anomalies in the network and indicate the extent to which they affect traffic flows, the Spectral Graph Wavelet Transform (SGWT) is applied to a center based graph model of air traffic. When applied to simulations based on historical flight plans, it identified the traffic flows between centers that have the greatest impact on either neighboring flows, or flows between centers many centers away. Like the CWT, however, it can be difficult to interpret SGWT results and relate them to simulations where major TMIs are implemented, and more research may be warranted in this area. These frequency analysis techniques can detect off-nominal air traffic behavior, but due to the nature of air traffic time series data, so far they prove difficult to apply in a way that provides significant insight or specific identification of traffic patterns.

An agent-based model for queue formation of powered two-wheelers in heterogeneous traffic

NASA Astrophysics Data System (ADS)

Lee, Tzu-Chang; Wong, K. I.

2016-11-01

This paper presents an agent-based model (ABM) for simulating the queue formation of powered two-wheelers (PTWs) in heterogeneous traffic at a signalized intersection. The main novelty is that the proposed interaction rule describing the position choice behavior of PTWs when queuing in heterogeneous traffic can capture the stochastic nature of the decision making process. The interaction rule is formulated as a multinomial logit model, which is calibrated by using a microscopic traffic trajectory dataset obtained from video footage. The ABM is validated against the survey data for the vehicular trajectory patterns, queuing patterns, queue lengths, and discharge rates. The results demonstrate that the proposed model is capable of replicating the observed queue formation process for heterogeneous traffic.

Determining a strategy for efficiently managing sign retroreflectivity.

DOT National Transportation Integrated Search

2013-01-01

The Manual on Uniform Traffic : Control Devices (MUTCD) required : minimum retroreflectivity levels for : roadway signs and the Federal Highway : Administration required that a plan be in place : by 2012 to track roadway sign retroreflectivity. : The...

The importance of antipersistence for traffic jams

NASA Astrophysics Data System (ADS)

Krause, Sebastian M.; Habel, Lars; Guhr, Thomas; Schreckenberg, Michael

2017-05-01

Universal characteristics of road networks and traffic patterns can help to forecast and control traffic congestion. The antipersistence of traffic flow time series has been found for many data sets, but its relevance for congestion has been overseen. Based on empirical data from motorways in Germany, we study how antipersistence of traffic flow time-series impacts the duration of traffic congestion on a wide range of time scales. We find a large number of short-lasting traffic jams, which implies a large risk for rear-end collisions.

Spatial correlation analysis of urban traffic state under a perspective of community detection

NASA Astrophysics Data System (ADS)

Yang, Yanfang; Cao, Jiandong; Qin, Yong; Jia, Limin; Dong, Honghui; Zhang, Aomuhan

2018-05-01

Understanding the spatial correlation of urban traffic state is essential for identifying the evolution patterns of urban traffic state. However, the distribution of traffic state always has characteristics of large spatial span and heterogeneity. This paper adapts the concept of community detection to the correlation network of urban traffic state and proposes a new perspective to identify the spatial correlation patterns of traffic state. In the proposed urban traffic network, the nodes represent road segments, and an edge between a pair of nodes is added depending on the result of significance test for the corresponding correlation of traffic state. Further, the process of community detection in the urban traffic network (named GWPA-K-means) is applied to analyze the spatial dependency of traffic state. The proposed method extends the traditional K-means algorithm in two steps: (i) redefines the initial cluster centers by two properties of nodes (the GWPA value and the minimum shortest path length); (ii) utilizes the weight signal propagation process to transfer the topological information of the urban traffic network into a node similarity matrix. Finally, numerical experiments are conducted on a simple network and a real urban road network in Beijing. The results show that GWPA-K-means algorithm is valid in spatial correlation analysis of traffic state. The network science and community structure analysis perform well in describing the spatial heterogeneity of traffic state on a large spatial scale.

Complexity of spatiotemporal traffic phenomena in flow of identical drivers: Explanation based on fundamental hypothesis of three-phase theory

NASA Astrophysics Data System (ADS)

Kerner, Boris S.

2012-03-01

Based on numerical simulations of a stochastic three-phase traffic flow model, we reveal the physics of the fundamental hypothesis of three-phase theory that, in contrast with a fundamental diagram of classical traffic flow theories, postulates the existence of a two-dimensional (2D) region of steady states of synchronized flow where a driver makes an arbitrary choice of a space gap (time headway) to the preceding vehicle. We find that macroscopic and microscopic spatiotemporal effects of the entire complexity of traffic congestion observed up to now in real measured traffic data can be explained by simulations of traffic flow consisting of identical drivers and vehicles, if a microscopic model used in these simulations incorporates the fundamental hypothesis of three-phase theory. It is shown that the driver's choice of space gaps within the 2D region of synchronized flow associated with the fundamental hypothesis of three-phase theory can qualitatively change types of congested patterns that can emerge at a highway bottleneck. In particular, if drivers choose long enough spaces gaps associated with the fundamental hypothesis, then general patterns, which consist of synchronized flow and wide moving jams, do not emerge independent of the flow rates and bottleneck characteristics: Even at a heavy bottleneck leading to a very low speed within congested patterns, only synchronized flow patterns occur in which no wide moving jams emerge spontaneously.

Complexity of spatiotemporal traffic phenomena in flow of identical drivers: explanation based on fundamental hypothesis of three-phase theory.

PubMed

Kerner, Boris S

2012-03-01

Based on numerical simulations of a stochastic three-phase traffic flow model, we reveal the physics of the fundamental hypothesis of three-phase theory that, in contrast with a fundamental diagram of classical traffic flow theories, postulates the existence of a two-dimensional (2D) region of steady states of synchronized flow where a driver makes an arbitrary choice of a space gap (time headway) to the preceding vehicle. We find that macroscopic and microscopic spatiotemporal effects of the entire complexity of traffic congestion observed up to now in real measured traffic data can be explained by simulations of traffic flow consisting of identical drivers and vehicles, if a microscopic model used in these simulations incorporates the fundamental hypothesis of three-phase theory. It is shown that the driver's choice of space gaps within the 2D region of synchronized flow associated with the fundamental hypothesis of three-phase theory can qualitatively change types of congested patterns that can emerge at a highway bottleneck. In particular, if drivers choose long enough spaces gaps associated with the fundamental hypothesis, then general patterns, which consist of synchronized flow and wide moving jams, do not emerge independent of the flow rates and bottleneck characteristics: Even at a heavy bottleneck leading to a very low speed within congested patterns, only synchronized flow patterns occur in which no wide moving jams emerge spontaneously.

Statistical modeling of the Internet traffic dynamics: To which extent do we need long-term correlations?

NASA Astrophysics Data System (ADS)

Markelov, Oleg; Nguyen Duc, Viet; Bogachev, Mikhail

2017-11-01

Recently we have suggested a universal superstatistical model of user access patterns and aggregated network traffic. The model takes into account the irregular character of end user access patterns on the web via the non-exponential distributions of the local access rates, but neglects the long-term correlations between these rates. While the model is accurate for quasi-stationary traffic records, its performance under highly variable and especially non-stationary access dynamics remains questionable. In this paper, using an example of the traffic patterns from a highly loaded network cluster hosting the website of the 1998 FIFA World Cup, we suggest a generalization of the previously suggested superstatistical model by introducing long-term correlations between access rates. Using queueing system simulations, we show explicitly that this generalization is essential for modeling network nodes with highly non-stationary access patterns, where neglecting long-term correlations leads to the underestimation of the empirical average sojourn time by several decades under high throughput utilization.

Many particle approximation of the Aw-Rascle-Zhang second order model for vehicular traffic.

PubMed

Francesco, Marco Di; Fagioli, Simone; Rosini, Massimiliano D

2017-02-01

We consider the follow-the-leader approximation of the Aw-Rascle-Zhang (ARZ) model for traffic flow in a multi population formulation. We prove rigorous convergence to weak solutions of the ARZ system in the many particle limit in presence of vacuum. The result is based on uniform BV estimates on the discrete particle velocity. We complement our result with numerical simulations of the particle method compared with some exact solutions to the Riemann problem of the ARZ system.

Application research on temporal GIS in the transportation information management system

NASA Astrophysics Data System (ADS)

Wang, Wei; Qin, Qianqing; Wang, Chao

2006-10-01

The application, development and key matters of applying spatio-temporal GIS to traffic information management system are discussed in this paper by introducing the development of spatio-temporal database, current models of spatio-temporal data, traits of traffic information management system. This paper proposes a method of organizing spatio-temporal data taking road object changes into consideration, and describes its data structure in 3 aspects, including structure of spatio-temporal object, organizing method spatio-temporal data and storage means of spatio-temporal data. Trying to manage types of spatio-temporal data involved in traffic system, such as road information, river information, railway information, social and economical data, and etc, uniformly, efficiently and with low redundancy.

Urban snow indicates pollution originating from road traffic.

PubMed

Kuoppamäki, Kirsi; Setälä, Heikki; Rantalainen, Anna-Lea; Kotze, D Johan

2014-12-01

Traffic is a major source of pollutants in cities. In this well-replicated study we analysed a broad array of contaminants in snowpacks along roads of different traffic intensities. The majority of pollutants showed a similar pattern with respect to traffic intensity: pH and conductivity as well as concentrations of PAHs, total suspended solids, phosphorus and most heavy metals were higher next to high intensity roads compared to low intensity roads. These pollutant levels also decreased considerably up to 5 m distance from the roads. Furthermore, apart from nitrogen, these variables increased in concentration from control sites in urban forest patches to road bank sites next to roads of low, intermediate and high traffic intensities. The deposition pattern of various traffic-derived pollutants--whether gaseous or particle-bound--was the same. Such information can be useful for the purposes of managing pollutants in urban areas. Copyright © 2014 Elsevier Ltd. All rights reserved.

Three Dimensional Sector Design with Optimal Number of Sectors

NASA Technical Reports Server (NTRS)

Xue, Min

2010-01-01

In the national airspace system, sectors get overloaded due to high traffic demand and inefficient airspace designs. Overloads can be eliminated in some cases by redesigning sector boundaries. This paper extends the Voronoi-based sector design method by automatically selecting the number of sectors, allowing three-dimensional partitions, and enforcing traffic pattern conformance. The method was used to design sectors at Fort-Worth and Indianapolis centers for current traffic scenarios. Results show that new designs can eliminate overloaded sectors, although not in all cases, reduce the number of necessary sectors, and conform to major traffic patterns. Overall, the new methodology produces enhanced and efficient sector designs.

Manual on uniform traffic control devices for streets and highways

DOT National Transportation Integrated Search

1995-02-01

The fourth working paper in Phase 1 of the Comprehensive Truck Size and Weight Study discusses the technical relationships of policy consequence concerning bridges. It presents information on bridge design considerations, truck characteristics affect...

Development of guidelines for the installation of marked crosswalks.

DOT National Transportation Integrated Search

2004-01-01

The Manual on Uniform Traffic Control Devices (MUTCD) provides little guidance on the installation of marked crosswalks, especially at locations other than intersections, i.e., mid-block locations. Crosswalks have typically been installed and designe...

Who are the traffic offenders among ethnic groups and why?

PubMed

Elias, Wafa; Blank-Gomel, Aharon; Habib-Matar, Caroline; Shiftan, Yoram

2016-06-01

Marginalized populations, particularly ethnic minorities, are often at a higher risk of being involved in traffic crashes and committing traffic violations. Prominent explanations for this "ethnic traffic risk gap" include cultural and socioeconomic factors, usually measured at an aggregate level. In particular, it has been hypothesized that ethnic minorities commit traffic violations as a form of social resistance to what they perceive to be an oppressing regime. The current study examined the mechanisms underlying traffic violations at the individual level within a single ethnic minority, Israeli-Arabs. The study sample (n=231) included a group of known offenders (n=60) and non-offenders (n=171), all of which completed the Traffic Violation Questionnaire. The results show that offenders and non-offenders tended to have different types of occupations, although these did not translate into significant differences in level of income. Offenders reported significantly lower levels of trust in some hegemonic institutions (the police, government ministries) but not others (parliament, the juridical system). However, offenders displayed remarkably different daily activity patterns, including much higher exposure to traffic (3h/day vs. 0.75) and more complex trip patterns. Our results find little support for the social resistance hypothesis, as it fails to explain the differential treatment of hegemonic institutions. Daily activity patterns stand out as a central mechanism influencing the risk of violations. These results suggest policymakers should adopt a holistic approach for traffic safety interventions but avoid monolithic views of ethnic minorities which may lead to an inefficient use of resources. Copyright © 2016 Elsevier Ltd. All rights reserved.

Knowledge and prevalence of risk factors for arterial hypertension and blood pressure pattern among bankers and traffic wardens in Ilorin, Nigeria.

PubMed

Salaudeen, A G; Musa, O I; Babatunde, O A; Atoyebi, O A; Durowade, K A; Omokanye, L O

2014-09-01

High job strain, mental stress, sedentary lifestyle, increase in BMI are among the factors associated with significantly higher incidence of hypertension. The job of bank employees is both sedentary in nature and accompanies high mental stress. The aim of this study is to assess the level of knowledge of risk factors among respondents and to compare the blood pressure pattern of bankers and traffic wardens. The study design is a descriptive cross-sectional conducted among bankers and traffic wardens in Ilorin to determine the pattern and knowledge of blood pressure. Self-administered questionnaires, weighing scale (Omron Digital scale), stadiometer and sphygmomanometer were used as the research instruments. Simple random sampling was used to select respondents involved in the study. The prevalence of hypertension in this study was 34.4% in bankers and 22.2% in traffic wardens. The risk factors the bankers commonly had knowledge of are alcohol, obesity, high salt intake, certain drugs, stress, emotional problems and family history while the traffic wardens commonly had knowledge of all these in addition to cigarette smoking. Also, more bankers (32.2%) than traffic wardens (13.3%) were smoking cigarette and more of these cigarette smokers that are bankers (17.8%) had elevated blood pressure compared to the traffic wardens (3.3%). Workers in the banking industry as well as traffic wardens should be better educated about the risk factors of hypertension and bankers should be encouraged to create time for exercise.

23 CFR 630.1102 - Purpose.

Code of Federal Regulations, 2010 CFR

2010-04-01

... zone fatalities and injuries to workers and road users by establishing minimum requirements and..., installation and maintenance of temporary traffic control devices, and use of uniformed law enforcement officers during construction, utility, and maintenance operations, and by requiring contract pay items to...

23 CFR Parts 1345-1399 - [RESERVED

Code of Federal Regulations, 2013 CFR

2013-04-01

... 23 Highways 1 2013-04-01 2013-04-01 false [RESERVED] 1345 PARTS 1345-1399 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION UNIFORM CRITERIA FOR STATE OBSERVATIONAL SURVEYS OF SEAT BELT USE Administrative Requirements Annual reporting requirements. PARTS 1345...

Development of uniform standards for allowable lane closure : final report, September 2008.

DOT National Transportation Integrated Search

2008-09-01

Procedures for determining allowable lane closure hours to perform maintenance, construction, resurfacing, regional permit and major access permit work on the state highway system were evaluated. The current process involves the collection of traffic...

Temporal Patterns of Road Traffic Injuries in Iran

PubMed Central

Khorshidi, Ali; Ainy, Elaheh; Hashemi Nazari, Seyed Saeed; Soori, Hamid

2016-01-01

Background Road traffic injuries (RTIs) are the main causes of death and disability in Iran. However, very few studies about the temporal variations of RTIs have been published to date. Objectives This study was conducted to investigate the temporal pattern of RTIs in Iran in 2012. Materials and Methods All road traffic accidents (RTAs) reported to traffic police during a one-year period (March 21, 2012 through March 21, 2013) were investigated after obtaining permission from the law enforcement force of the Islamic Republic of Iran. Distributions of RTAs were obtained for season, month, week, and hour scales, and for long holidays (more than one day) and the day prior to long holidays (DPLH). The final analysis was carried out using the Poisson regression model to calculate incidence rate ratios for RTIs. All analyses were conducted using STATA 13.1 and Excel software; statistical significance was set at P < 0.05. Results A total of 452,192 RTAs were examined. The estimated rate of all accidents was 219 per 10,000 registered vehicles, or 595 per 100,000 people. About 28% of all RTAs, and more than one third of fatal RTAs, occurred during the summer months. The incidence rate for all traffic accidents on DPLH was 1.20, compared to workdays as a reference category, and it was 1.40 for fatal crashes. The rate of fatal road traffic accidents in outer cities was 3.2 times higher than in inner ones. Conclusions Our findings reveal that there are temporal variations in traffic accidents, and long holidays significantly influence accident rates. Traffic injuries have different patterns on outer/inner city roads, based on weekday and holiday status. Thus, these findings could be used to create effective initiatives aimed at traffic management. PMID:27703958

Universal model for collective access patterns in the Internet traffic dynamics: A superstatistical approach

NASA Astrophysics Data System (ADS)

Tamazian, A.; Nguyen, V. D.; Markelov, O. A.; Bogachev, M. I.

2016-07-01

We suggest a universal phenomenological description for the collective access patterns in the Internet traffic dynamics both at local and wide area network levels that takes into account erratic fluctuations imposed by cooperative user behaviour. Our description is based on the superstatistical approach and leads to the q-exponential inter-session time and session size distributions that are also in perfect agreement with empirical observations. The validity of the proposed description is confirmed explicitly by the analysis of complete 10-day traffic traces from the WIDE backbone link and from the local campus area network downlink from the Internet Service Provider. Remarkably, the same functional forms have been observed in the historic access patterns from single WWW servers. The suggested approach effectively accounts for the complex interplay of both “calm” and “bursty” user access patterns within a single-model setting. It also provides average sojourn time estimates with reasonable accuracy, as indicated by the queuing system performance simulation, this way largely overcoming the failure of Poisson modelling of the Internet traffic dynamics.

Pattern of emergency room mortality among road traffic crash victims.

PubMed

Babalola, Oladimeji Ranti; Oluwadiya, Kehinde; Vrgoč, Goran; Akpati, Ugochukwu; Sindik, Joško; Čoklo, Miran; Marinović, Marin; Bakota, Bore

2015-11-01

Road traffic injuries are a major cause of death in the emergency room. The goal of this study was to highlight the demographic pattern of road traffic-related deaths in the accident and emergency room of a regional trauma centre. This was a 5-year retrospective study in which road traffic-related cases of emergency room mortality between June 2009 and June 2014 were reviewed. A total of 33 road traffic crash-related deaths occurred during this period with a male-to-female ratio of 2.3:1. Most of these patients were pedestrians with severe injuries involving two or more Abbreviated Injury Scale (AIS) coded regions. The mean time between injury and presentation in the first trauma facility was 112.1 (±55.4)min, and between presentation in the emergency room and death was 410 (±645)min. Mangled lower extremity, bilateral long bone lower limb fractures, pelvic injuries, blunt injuries to the chest and abdomen, and cranial fossae fractures were the common injury pattern. Median ISS and NISS in these patients were 22 (interquartile range [IQR]=11) and 25 (IQR=17), respectively. Severe injuries, delayed presentation, multiple referrals and delayed resuscitative measures contribute to road traffic crash-related mortality. Copyright © 2015 Elsevier Ltd. All rights reserved.

A novel interacting multiple model based network intrusion detection scheme

NASA Astrophysics Data System (ADS)

Xin, Ruichi; Venkatasubramanian, Vijay; Leung, Henry

2006-04-01

In today's information age, information and network security are of primary importance to any organization. Network intrusion is a serious threat to security of computers and data networks. In internet protocol (IP) based network, intrusions originate in different kinds of packets/messages contained in the open system interconnection (OSI) layer 3 or higher layers. Network intrusion detection and prevention systems observe the layer 3 packets (or layer 4 to 7 messages) to screen for intrusions and security threats. Signature based methods use a pre-existing database that document intrusion patterns as perceived in the layer 3 to 7 protocol traffics and match the incoming traffic for potential intrusion attacks. Alternately, network traffic data can be modeled and any huge anomaly from the established traffic pattern can be detected as network intrusion. The latter method, also known as anomaly based detection is gaining popularity for its versatility in learning new patterns and discovering new attacks. It is apparent that for a reliable performance, an accurate model of the network data needs to be established. In this paper, we illustrate using collected data that network traffic is seldom stationary. We propose the use of multiple models to accurately represent the traffic data. The improvement in reliability of the proposed model is verified by measuring the detection and false alarm rates on several datasets.

Disparities in Exposure to Automobile and Truck Traffic and Vehicle Emissions Near the Los Angeles–Long Beach Port Complex

PubMed Central

Li, Wei; Wu, Jun

2014-01-01

Objectives. We assessed how traffic and mobile-source air pollution impacts are distributed across racial/ethnic and socioeconomically diverse groups in port-adjacent communities in southern Los Angeles County, which may experience divergent levels of exposure to port-related heavy-duty diesel truck traffic because of existing residential and land use patterns. Methods. We used spatial regression techniques to assess the association of neighborhood racial/ethnic and socioeconomic composition with residential parcel-level traffic and vehicle-related fine particulate matter exposure after accounting for built environment and land use factors. Results. After controlling for factors associated with traffic generation, we found that a higher percentage of nearby Black and Asian/Pacific Islander residents was associated with higher exposure, a higher percentage of Hispanic residents was associated with higher traffic exposure but lower vehicle particulate matter exposure, and areas with lower socioeconomic status experienced lower exposure. Conclusions. Disparities in traffic and vehicle particulate matter exposure are nuanced depending on the exposure metric used, the distribution of the traffic and emissions, and pollutant dispersal patterns. Future comparative research is needed to assess potential disparities in other transportation and goods movement corridors. PMID:23678919

Disparities in exposure to automobile and truck traffic and vehicle emissions near the Los Angeles-Long Beach port complex.

PubMed

Houston, Douglas; Li, Wei; Wu, Jun

2014-01-01

We assessed how traffic and mobile-source air pollution impacts are distributed across racial/ethnic and socioeconomically diverse groups in port-adjacent communities in southern Los Angeles County, which may experience divergent levels of exposure to port-related heavy-duty diesel truck traffic because of existing residential and land use patterns. We used spatial regression techniques to assess the association of neighborhood racial/ethnic and socioeconomic composition with residential parcel-level traffic and vehicle-related fine particulate matter exposure after accounting for built environment and land use factors. After controlling for factors associated with traffic generation, we found that a higher percentage of nearby Black and Asian/Pacific Islander residents was associated with higher exposure, a higher percentage of Hispanic residents was associated with higher traffic exposure but lower vehicle particulate matter exposure, and areas with lower socioeconomic status experienced lower exposure. Disparities in traffic and vehicle particulate matter exposure are nuanced depending on the exposure metric used, the distribution of the traffic and emissions, and pollutant dispersal patterns. Future comparative research is needed to assess potential disparities in other transportation and goods movement corridors.

Safety impacts of different speed limits on cars and trucks : final report

DOT National Transportation Integrated Search

1994-05-01

The objectives of this study were to determine whether differential or uniform speed limits are more beneficial to transportation safety and traffic operations on Interstate highways. The approach to achieving this objective was to examine speed and ...

23 CFR 1200.22 - State traffic safety information system improvements grants.

Code of Federal Regulations, 2013 CFR

2013-04-01

... measures to be used to demonstrate quantitative progress in the accuracy, completeness, timeliness... to implement, provides an explanation. (d) Requirement for quantitative improvement. A State shall demonstrate quantitative improvement in the data attributes of accuracy, completeness, timeliness, uniformity...

23 CFR 1200.22 - State traffic safety information system improvements grants.

Code of Federal Regulations, 2014 CFR

2014-04-01

... measures to be used to demonstrate quantitative progress in the accuracy, completeness, timeliness... to implement, provides an explanation. (d) Requirement for quantitative improvement. A State shall demonstrate quantitative improvement in the data attributes of accuracy, completeness, timeliness, uniformity...

Evaluation of retroreflective material on stop sign posts in Virginia.

DOT National Transportation Integrated Search

2009-01-01

The 2003 Manual on Uniform Traffic Control Devices (MUTCD) provides departments of transportation (DOTs) the option of using retroreflective material on sign posts when the DOTs determine that there is a need to draw attention to the sign, especially...

Analysis of AS112 Traffic

DTIC Science & Technology

2007-06-01

UPDATEs • TCP UPDATEs 9© 2007 Carnegie Mellon University A queries • Clients asking blackhole -1 and blackhole -2 for prisoner • Results are not cached...Clients requesting the DNS name of an RFC1918 address • Simple queries sent to blackhole -1 and blackhole -2 • Uniformity makes trending very easy...dns.qry.type == 0x000c • Clients requesting the DNS name of an RFC1918 address • Simple queries sent to blackhole -1 and blackhole -2 • Uniformity makes

Determination of network origin-destination matrices using partial link traffic counts and virtual sensor information in an integrated corridor management framework.

DOT National Transportation Integrated Search

2014-04-01

Trip origin-destination (O-D) demand matrices are critical components in transportation network : modeling, and provide essential information on trip distributions and corresponding spatiotemporal : traffic patterns in traffic zones in vehicular netw...

Phase diagram of congested traffic flow: An empirical study

PubMed

Lee; Lee; Kim

2000-10-01

We analyze traffic data from a highway section containing one effective on-ramp. Based on two criteria, local velocity variation patterns and expansion (or nonexpansion) of congested regions, three distinct congested traffic states are identified. These states appear at different levels of the upstream flux and the on-ramp flux, thereby generating a phase digram of the congested traffic flow. Observed traffic states are compared with recent theoretical analyses and both agreeing and disagreeing features are found.

23 CFR 1235.8 - Reciprocity.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Reciprocity. 1235.8 Section 1235.8 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GUIDELINES UNIFORM SYSTEM FOR PARKING FOR PERSONS WITH DISABILITIES § 1235.8 Reciprocity. The State system...

23 CFR 1235.8 - Reciprocity.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 23 Highways 1 2012-04-01 2012-04-01 false Reciprocity. 1235.8 Section 1235.8 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GUIDELINES UNIFORM SYSTEM FOR PARKING FOR PERSONS WITH DISABILITIES § 1235.8 Reciprocity. The State system...

23 CFR 1235.8 - Reciprocity.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 23 Highways 1 2013-04-01 2013-04-01 false Reciprocity. 1235.8 Section 1235.8 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GUIDELINES UNIFORM SYSTEM FOR PARKING FOR PERSONS WITH DISABILITIES § 1235.8 Reciprocity. The State system...

23 CFR 1235.8 - Reciprocity.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 23 Highways 1 2011-04-01 2011-04-01 false Reciprocity. 1235.8 Section 1235.8 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GUIDELINES UNIFORM SYSTEM FOR PARKING FOR PERSONS WITH DISABILITIES § 1235.8 Reciprocity. The State system...

23 CFR 1235.8 - Reciprocity.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 23 Highways 1 2014-04-01 2014-04-01 false Reciprocity. 1235.8 Section 1235.8 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GUIDELINES UNIFORM SYSTEM FOR PARKING FOR PERSONS WITH DISABILITIES § 1235.8 Reciprocity. The State system...

Guidelines for the use of raised pavement markers

DOT National Transportation Integrated Search

1998-10-01

The Manual on Uniform Traffic Control Devices (MUTCD, 1988) provides a general outline for how Raised Pavement Markers (RPMs) should be used, but more specific information is required in order to produce a set of guidelines that are usable by a field...

23 CFR 1340.6 - Assignment of observation times.

Code of Federal Regulations, 2012 CFR

2012-04-01

... Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION UNIFORM CRITERIA FOR... sites. (c) Grouping of observation sites in close geographic proximity. Observations sites in close geographic proximity may be grouped to reduce data collection burdens if: (1) The first assignment of an...

23 CFR 1340.6 - Assignment of observation times.

Code of Federal Regulations, 2014 CFR

2014-04-01

... Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION UNIFORM CRITERIA FOR... sites. (c) Grouping of observation sites in close geographic proximity. Observations sites in close geographic proximity may be grouped to reduce data collection burdens if: (1) The first assignment of an...

23 CFR 1340.6 - Assignment of observation times.

Code of Federal Regulations, 2013 CFR

2013-04-01

... Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION UNIFORM CRITERIA FOR... sites. (c) Grouping of observation sites in close geographic proximity. Observations sites in close geographic proximity may be grouped to reduce data collection burdens if: (1) The first assignment of an...

49 CFR 234.5 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... devices for daytime flagging include “ STOP/SLOW” paddles or red flags. For nighttime flagging, a... Administration's Manual on Uniform Traffic Control Devices addresses standards and guides for flaggers and... follow them to the greatest extent possible. Copies of the latest MUTCD provisions regarding flagging...

Determining a strategy for efficiently managing sign retroreflectivity in New Hampshire.

DOT National Transportation Integrated Search

2012-05-01

The Manual on Uniform Traffic Control Devices (MUTCD) has developed minimum retroreflectivity requirements for sign sheeting that will : become a federal mandate for roadside signs in 2015 and for overhead signs in 2018. In 2012, the New Hampshire De...

What are the differences in injury patterns of young and elderly traffic accident fatalities considering death on scene and death in hospital?

PubMed

Heinrich, Daniela; Holzmann, Christopher; Wagner, Anja; Fischer, Anja; Pfeifer, Roman; Graw, Matthias; Schick, Sylvia

2017-07-01

Older traffic participants have higher risks of injury than the population up to 65 years in case of comparable road traffic accidents and further, higher mortality rates at comparable injury severities. Rib fractures as risk factors are currently discussed. However, death on scene is associated with hardly survivable injuries and might not be a matter of neither rib fractures nor age. As 60% of traffic accident fatalities are estimated to die on scene, they are not captured in hospital-based trauma registries and injury patterns remain unknown. Our database comprises 309 road traffic fatalities, autopsied at the Institute of Legal Medicine Munich in 2004 and 2005. Injuries are coded according to Abbreviated Injury Scale, AIS© 2005 update 2008 [1]. Data used for this analysis are age, sex, site of death, site of accident, traffic participation mode, measures of injury severity, and rib fractures. The injury patterns of elderly, aged 65+ years, are compared to the younger ones divided by their site of death. Elderly with death on scene more often show serious thorax injuries and pelvic fractures than the younger. Some hints point towards older fatalities showing less frequently serious abdominal injuries. In hospital, elderly fatalities show lower Injury Severity Scores (ISSs) compared to the younger. The number of rib fractures is significantly higher for the elderly but is not the reason for death. Results show that young and old fatalities have different injury patterns and reveal first hints towards the need to analyze death on scene more in-depth.

On-board processing for future satellite communications systems: Satellite-Routed FDMA

NASA Astrophysics Data System (ADS)

Berk, G.; Christopher, P. F.; Hoffman, M.; Jean, P. N.; Rotholz, E.; White, B. E.

1981-05-01

A frequency division multiple access (FDMA) 30/20 GHz satellite communications architecture without on-board baseband processing is investigated. Conceptual system designs are suggested for domestic traffic models totaling 4 Gb/s of customer premises service (CPS) traffic and 6 Gb/s of trunking traffic. Emphasis is given to the CPS portion of the system which includes thousands of earth terminals with digital traffic ranging from a single 64 kb/s voice channel to hundreds of channels of voice, data, and video with an aggregate data rate of 33 Mb/s. A unique regional design concept that effectively smooths the non-uniform traffic distribution and greatly simplifies the satellite design is employed. The satellite antenna system forms thirty-two 0.33 deg beam on both the uplinks and the downlinks in one design. In another design matched to a traffic model with more dispersed users, there are twenty-four 0.33 deg beams and twenty-one 0.7 deg beams. Detailed system design techniques show that a single satellite producing approximately 5 kW of dc power is capable of handling at least 75% of the postulated traffic. A detailed cost model of the ground segment and estimated system costs based on current information from manufacturers are presented.

On-board processing for future satellite communications systems: Satellite-Routed FDMA

NASA Technical Reports Server (NTRS)

Berk, G.; Christopher, P. F.; Hoffman, M.; Jean, P. N.; Rotholz, E.; White, B. E.

1981-01-01

A frequency division multiple access (FDMA) 30/20 GHz satellite communications architecture without on-board baseband processing is investigated. Conceptual system designs are suggested for domestic traffic models totaling 4 Gb/s of customer premises service (CPS) traffic and 6 Gb/s of trunking traffic. Emphasis is given to the CPS portion of the system which includes thousands of earth terminals with digital traffic ranging from a single 64 kb/s voice channel to hundreds of channels of voice, data, and video with an aggregate data rate of 33 Mb/s. A unique regional design concept that effectively smooths the non-uniform traffic distribution and greatly simplifies the satellite design is employed. The satellite antenna system forms thirty-two 0.33 deg beam on both the uplinks and the downlinks in one design. In another design matched to a traffic model with more dispersed users, there are twenty-four 0.33 deg beams and twenty-one 0.7 deg beams. Detailed system design techniques show that a single satellite producing approximately 5 kW of dc power is capable of handling at least 75% of the postulated traffic. A detailed cost model of the ground segment and estimated system costs based on current information from manufacturers are presented.

Injury pattern among non-fatal road traffic accident cases: a cross-sectional study in Central India.

PubMed

Ganveer, Gunjan B; Tiwari, Rajnarayan R

2005-01-01

What is the pattern of injuries among non-fatal cases of road traffic accidents? To study the pattern of injuries among non-fatal cases of road traffic accidents. Cross-sectional study. Nagpur, a city in central India. 423 non-fatal cases of road traffic accidents reporting for treatment to Indira Gandhi Medical College, Nagpur during 1999-2000. Demographic characteristics, accident characteristics. Percentages, proportions, Chi-square test. Out of total 423 subjects, 363 (85.8%) were male while only 60 (14.2%) were female subjects. Majority of the victims (75%) were in the age group 18- 37 years. Sideways collision was the most common type of accident seen in 269 (63.59%) cases. Two wheelers and LMV were the common vehicle being involved in accidents (69.97%) and these accidents were almost equally distributed in both half of the day. Fracture of the bones was the common injury afflicted to the victims followed by multiple injuries like blunt injury, abrasions and lacerations. Lower extremity was involved in 192 (45.39%) cases while multiple sites were affected in 114 (26.95%) cases. In the present study, the fractures were the commonest injury among the victims of non-fatal road traffic accidents.

Traffic citation rates among drivers of different residency status in the United States.

PubMed

Romano, Eduardo; Tippetts, Scott; Fell, James; Eichelberger, Angela; Grosz, Milton; Wiliszowski, Connie

2013-03-01

Racial/ethnic groups in the United States may be overrepresented in motor-vehicle incidents (crashes and violations), particularly among low-acculturated immigrants coming from countries in which traffic laws are not well enforced. Some evidence suggests just the opposite. We collected and analyzed information on the residency status of licensed drivers in Florida and Tennessee to examine the hypothesis that the prevalence of seat-belt nonuse, DWI, speeding, and failures to obey a traffic signal was higher among recent immigrants than among US citizens. We rejected this hypothesis. Both in Florida and Tennessee, US citizens were more likely to be cited for DWI, seat-belt, or speeding violations than the noncitizens. However, immigrants were more often cited for failure-to-obey than US citizens. We concluded that residency status does, appear to play a role in the likelihood of traffic violations, but this role is far from uniform; varying depending upon the type of traffic violation, the racial/ethnic group, and the state in which the violation occurred. Copyright © 2012. Published by Elsevier Ltd.

Mass prophylaxis dispensing concerns: traffic and public access to PODs.

PubMed

Baccam, Prasith; Willauer, David; Krometis, Justin; Ma, Yongchang; Sen, Atri; Boechler, Michael

2011-06-01

The ability to quickly dispense postexposure prophylaxis (PEP) using multiple points of dispensing (PODs) following a bioterrorism event could potentially save a large proportion of those who were exposed, while failure in PEP dispensing could have dire public health consequences. A Monte Carlo simulation was developed to explore the traffic flow and parking around PODs under different arrival rates and how these factors might affect the utilization rate of POD workers. The results demonstrate that the public can reasonably access the PODs under ideal conditions assuming a stationary (uniform) arrival rate. For the 5 nonstationary arrival rates tested, however, the available parking spaces quickly become filled, causing long traffic queues and resulting in total processing times that range from 1 hour to over 6 hours. Basic planning considerations should include the use of physical barriers, signage, and traffic control officers to help direct vehicular and pedestrian access to the PODs. Furthermore, the parking and traffic surrounding PODs creates long queues of people waiting to access the PODs. Thus, POD staff are fully used approximately 90% of the time, which can lead to worker fatigue and burn out.

Impact of roof height non-uniformity on pollutant transport between a street canyon and intersections.

PubMed

Nosek, Štěpán; Kukačka, Libor; Jurčáková, Klára; Kellnerová, Radka; Jaňour, Zbyněk

2017-08-01

This paper presents an extension of our previous wind-tunnel study (Nosek et al., 2016) in which we highlighted the need for investigation of the removal mechanisms of traffic pollution from all openings of a 3D street canyon. The extension represents the pollution flux (turbulent and advective) measurements at the lateral openings of three different 3D street canyons for the winds perpendicular and oblique to the along-canyon axis. The pollution was simulated by emitting a passive gas (ethane) from a homogeneous ground-level line source positioned along the centreline of the investigated street canyons. The street canyons were formed by courtyard-type buildings of two different regular urban-array models. The first model has a uniform building roof height, while the second model has a non-uniform roof height along each building's wall. The mean flow and concentration fields at the canyons' lateral openings confirm the findings of other studies that the buildings' roof-height variability at the intersections plays an important role in the dispersion of the traffic pollutants within the canyons. For the perpendicular wind, the non-uniform roof-height canyon appreciably removes or entrains the pollutant through its lateral openings, contrary to the uniform canyon, where the pollutant was removed primarily through the top. The analysis of the turbulent mass transport revealed that the coherent flow structures of the lateral momentum transport correlate with the ventilation processes at the lateral openings of all studied canyons. These flow structures coincide at the same areas and hence simultaneously transport the pollutant in opposite directions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Impact of edge lines on safety of rural two-lane highways.

DOT National Transportation Integrated Search

2005-10-01

This report documents the results of the project for Impact of Edge Lines on Safety of Rural Two Lane Highways. This research project was initiated in the effort of compliance with the updated version of the Manual on Uniform Traffic Control De...

Safety impacts of differential speed limits on rural interstate highways

DOT National Transportation Integrated Search

2005-10-01

To compare the safety effects of a uniform speed limit (USL) for all vehicles as opposed to a differential speed limit (DSL) for cars and heavy trucks, detailed crash data, speed monitoring data, and traffic volumes were sought for rural interstate h...

Whiplash injury is more than neck pain: a population-based study of pain localization after traffic injury.

PubMed

Hincapié, Cesar A; Cassidy, J David; Côté, Pierre; Carroll, Linda J; Guzmán, Jaime

2010-04-01

To describe the distribution of bodily pain and identify common patterns of pain localization after traffic injury. Cross-sectional analysis of a population-based cohort of 6481 Saskatchewan residents who were treated or filed an auto insurance claim within 30 days of traffic injury or both. The prevalence of pain in each of 13 body areas was calculated and compared with pain confined exclusively to each of these areas. Principal component analysis was used to identify the main patterns of pain localization after traffic injury. Irrespective of pain in other areas, 86% of respondents reported posterior neck pain, 72% indicated head pain, and 60% noted lumbar back pain. Ninety-five percent of claimants reported some pain within the posterior trunk region, comprising the posterior neck, shoulder, mid-back, lumbar, and buttock areas. Only 0.4% of respondents reported posterior neck pain only. Four main patterns accounted for 60% of the variance in pain localization: 1) upper anterior trunk and upper extremity pain; 2) head, posterior neck, and upper posterior trunk pain; 3) low back pain; and 4) lower anterior trunk and lower extremity pain. Pain after traffic injury is most commonly reported in multiple body areas; isolated neck pain is extremely rare. These results have implications for clinical management of traffic injuries and interpretation of whiplash-related trials.

Real-time detection and classification of anomalous events in streaming data

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

Ferragut, Erik M.; Goodall, John R.; Iannacone, Michael D.

2016-04-19

A system is described for receiving a stream of events and scoring the events based on anomalousness and maliciousness (or other classification). The events can be displayed to a user in user-defined groupings in an animated fashion. The system can include a plurality of anomaly detectors that together implement an algorithm to identify low probability events and detect atypical traffic patterns. The atypical traffic patterns can then be classified as being of interest or not. In one particular example, in a network environment, the classification can be whether the network traffic is malicious or not.

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.

Traffic Feasibility Study for a Grade Separator at a Busy Intersection in Vellore

NASA Astrophysics Data System (ADS)

Vasantha Kumar, S.; Gulati, Himanshu; Arora, Shivam

2017-11-01

One of the byproduct of urbanization is traffic congestion and before suggesting any solutions to reduce congestion, understanding the present context becomes very important. Study of traffic volumes at busy intersections to find the percentage composition of different vehicle types, directional distribution and peak hour traffic volume is a first step towards understanding the present context of traffic. Hence in the present study, one of the busy intersections in Vellore, namely, Gandhi nagar intersection in Vellore-Katpadi road was selected and traffic flow data was collected using video surveys. It was found that at the selected intersection, the two wheelers and three wheelers alone share 80% of the total traffic when compared to other vehicle types. Nearly 700 trucks and multi axle trailers were observed to pass through the intersection during the analysis period of five hours. That is, on an average 2 trucks/multi axle trailers were passing through the intersection in each minute. As like in other major cities, entry of trucks and other heavy vehicles such as multi axle trailers into the city needs to be banned during peak hours for smooth flow of traffic within city limits. A highest hourly volume of 6939 PCU’s was observed between 4 and 5 pm at the selected intersection. By assuming a 10% uniform traffic growth every year, it was found that after about 4 years, i.e., in 2019, the traffic volume at the intersection may reach 10,000 PCU’s and may warrant for a grade separator or interchange at the intersection.

Research on three-phase traffic flow modeling based on interaction range

NASA Astrophysics Data System (ADS)

Zeng, Jun-Wei; Yang, Xu-Gang; Qian, Yong-Sheng; Wei, Xu-Ting

2017-12-01

On the basis of the multiple velocity difference effect (MVDE) model and under short-range interaction, a new three-phase traffic flow model (S-MVDE) is proposed through careful consideration of the influence of the relationship between the speeds of the two adjacent cars on the running state of the rear car. The random slowing rule in the MVDE model is modified in order to emphasize the influence of vehicle interaction between two vehicles on the probability of vehicles’ deceleration. A single-lane model which without bottleneck structure under periodic boundary conditions is simulated, and it is proved that the traffic flow simulated by S-MVDE model will generate the synchronous flow of three-phase traffic theory. Under the open boundary, the model is expanded by adding an on-ramp, the congestion pattern caused by the bottleneck is simulated at different main road flow rates and on-ramp flow rates, which is compared with the traffic congestion pattern observed by Kerner et al. and it is found that the results are consistent with the congestion characteristics in the three-phase traffic flow theory.

78 FR 53497 - Uniform Procedures for State Highway Safety Grant Programs

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-29

...., Eastern Time, Monday through Friday, except Federal holidays. Whichever way you submit your comments... holidays. FOR FURTHER INFORMATION CONTACT: Barbara Sauers, Program Manager, National Highway Traffic Safety... Columbia, Puerto Rico, U.S. Virgin Islands, Guam, American Samoa, the Commonwealth of the Northern Mariana...

32 CFR 537.4 - Claims not collectible.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Deployment and Distribution Command (SDDC), formerly the Military Traffic Management Command (MTMC), for lost or destroyed shipments. (d) Where damage to assigned quarters, or equipment or furnishings therein, is collectible from a member of the uniformed services under 10 U.S.C. 2775. (e) Where the medical...

32 CFR 537.4 - Claims not collectible.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Deployment and Distribution Command (SDDC), formerly the Military Traffic Management Command (MTMC), for lost or destroyed shipments. (d) Where damage to assigned quarters, or equipment or furnishings therein, is collectible from a member of the uniformed services under 10 U.S.C. 2775. (e) Where the medical...

23 CFR 1200.40 - Expiration of the Highway Safety Plan.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 23 Highways 1 2013-04-01 2013-04-01 false Expiration of the Highway Safety Plan. 1200.40 Section 1200.40 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PROCEDURES FOR STATE HIGHWAY SAFETY PROGRAMS UNIFORM PROCEDURES FOR STATE...

23 CFR 1200.40 - Expiration of the Highway Safety Plan.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 23 Highways 1 2014-04-01 2014-04-01 false Expiration of the Highway Safety Plan. 1200.40 Section 1200.40 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PROCEDURES FOR STATE HIGHWAY SAFETY PROGRAMS UNIFORM PROCEDURES FOR STATE...

Empirical synchronized flow in oversaturated city traffic.

PubMed

Kerner, Boris S; Hemmerle, Peter; Koller, Micha; Hermanns, Gerhard; Klenov, Sergey L; Rehborn, Hubert; Schreckenberg, Michael

2014-09-01

Based on a study of anonymized GPS probe vehicle traces measured by personal navigation devices in vehicles randomly distributed in city traffic, empirical synchronized flow in oversaturated city traffic has been revealed. It turns out that real oversaturated city traffic resulting from speed breakdown in a city in most cases can be considered random spatiotemporal alternations between sequences of moving queues and synchronized flow patterns in which the moving queues do not occur.

Data traffic reduction schemes for sparse Cholesky factorizations

NASA Technical Reports Server (NTRS)

Naik, Vijay K.; Patrick, Merrell L.

1988-01-01

Load distribution schemes are presented which minimize the total data traffic in the Cholesky factorization of dense and sparse, symmetric, positive definite matrices on multiprocessor systems with local and shared memory. The total data traffic in factoring an n x n sparse, symmetric, positive definite matrix representing an n-vertex regular 2-D grid graph using n (sup alpha), alpha is equal to or less than 1, processors are shown to be O(n(sup 1 + alpha/2)). It is O(n(sup 3/2)), when n (sup alpha), alpha is equal to or greater than 1, processors are used. Under the conditions of uniform load distribution, these results are shown to be asymptotically optimal. The schemes allow efficient use of up to O(n) processors before the total data traffic reaches the maximum value of O(n(sup 3/2)). The partitioning employed within the scheme, allows a better utilization of the data accessed from shared memory than those of previously published methods.

Weighted complex network analysis of the Beijing subway system: Train and passenger flows

NASA Astrophysics Data System (ADS)

Feng, Jia; Li, Xiamiao; Mao, Baohua; Xu, Qi; Bai, Yun

2017-05-01

In recent years, complex network theory has become an important approach to the study of the structure and dynamics of traffic networks. However, because traffic data is difficult to collect, previous studies have usually focused on the physical topology of subway systems, whereas few studies have considered the characteristics of traffic flows through the network. Therefore, in this paper, we present a multi-layer model to analyze traffic flow patterns in subway networks, based on trip data and an operation timetable obtained from the Beijing Subway System. We characterize the patterns in terms of the spatiotemporal flow size distributions of both the train flow network and the passenger flow network. In addition, we describe the essential interactions between these two networks based on statistical analyses. The results of this study suggest that layered models of transportation systems can elucidate fundamental differences between the coexisting traffic flows and can also clarify the mechanism that causes these differences.

Traffic Congestion on a University Campus: A Consideration of Unconventional Remedies to Nontraditional Transportation Patterns

ERIC Educational Resources Information Center

Kaplan, Dave; Clapper, Thomas

2007-01-01

U.S. transportation data suggest that the number of vehicle miles traveled has far surpassed new capacity, resulting in increased traffic congestion in many communities throughout the country. This article reports on traffic congestion around a university campus located within a small town. The mix of trip purposes varies considerably in this…

The Skandia Report: A Report on Children in Traffic.

ERIC Educational Resources Information Center

Skandia Insurance Co., Stockholm (Sweden).

This study examined the traffic accidents in Sweden during 1968 and 1969 in which children up to and including the age of ten were actively involved. The major goal of the study was to illustrate the traffic behavior patterns of children in this age group. Data were analyzed under two broad categories: pedestrian accidents and bicycle accidents.…

Prognostic significance of specific injury patterns in casualties of traffic-related accidents.

PubMed

Calosevic, Srdjan; Lovric, Zvonimir

2015-11-01

Fatal triad and ipsilateral dyad are patterns of pedestrian injuries related to significant mortality in traffic-related accidents. The aim of this research was to investigate the correlation between specific injury patterns and fatal outcome in other participants of traffic-related accidents. This was a retrospective study of traffic-related accidents in the broader area of the city of Osijek in a five-year period from 1995 to 1999. Autopsy results from the Institute of Pathology and Forensic Medicine of the Clinical Hospital Centre Osijek were analysed of individuals who died after their accident. The total severity of injuries was measured using the ISS. Logistic regression analysis was used for assessing the correlation between specific injury patterns and an early outcome from the severe injury. There were 213 individuals included in the study: 72 pedestrians and 141 other participants (drivers, assistant drivers, passengers, cyclists and motorcyclists). A total of129 individuals died on the spot and 84 died in the hospital during the first 48h. Femoral and pelvic fracture, fatal triad and both variants of ipsilateral dyad were related to higher ISS values. Ipsilateral fracture of upper and lower extremities (ipsilateral dyad 1) was associated with a 4.59 times higher risk of an immediate fatal outcome in the total sample. In pedestrians, the risk was 5.99 higher, and in other participants, the risk was 4.11 times higher. Specific skeletal injuries and injury patterns are a significant indicator for total injury severity and related poor prognosis for all participants of traffic-related injuries, not only for pedestrians. In this study, the ipsilateral fracture of upper and lower extremity was related to the largest total severity of injuries and the poorest prognosis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Traffic dispersion through a series of signals with irregular split

NASA Astrophysics Data System (ADS)

Nagatani, Takashi

2016-01-01

We study the traffic behavior of a group of vehicles moving through a sequence of signals with irregular splits on a roadway. We present the stochastic model of vehicular traffic controlled by signals. The dynamic behavior of vehicular traffic is clarified by analyzing traffic pattern and travel time numerically. The group of vehicles breaks up more and more by the irregularity of signal's split. The traffic dispersion is induced by the irregular split. We show that the traffic dispersion depends highly on the cycle time and the strength of split's irregularity. Also, we study the traffic behavior through the series of signals at the green-wave strategy. The dependence of the travel time on offset time is derived for various values of cycle time. The region map of the traffic dispersion is shown in (cycle time, offset time)-space.

Crash risk analysis during fog conditions using real-time traffic data.

PubMed

Wu, Yina; Abdel-Aty, Mohamed; Lee, Jaeyoung

2018-05-01

This research investigates the changes of traffic characteristics and crash risks during fog conditions. Using real-time traffic flow and weather data at two regions in Florida, the traffic patterns at the fog duration were compared to the traffic patterns at the clear duration. It was found that the average 5-min speed and the average 5-min volume were prone to decreasing during fog. Based on previous studies, a "Crash Risk Increase Indicator (CRII)" was proposed to explore the differences of crash risk between fog and clear conditions. A binary logistic regression model was applied to link the increase of crash risks with traffic flow characteristics. The results suggested that the proposed indicator worked well in evaluating the increase of crash risk under fog condition. It was indicated that the crash risk was prone to increase at ramp vicinities in fog conditions. Also, the average 5-min volume during fog and the lane position are important factors for crash risk increase. The differences between the regions were also explored in this study. The results indicated that the locations with heavier traffic or locations at the lanes that were closest to the median in Region 2 were more likely to observe an increase in crash risks in fog conditions. It is expected that the proposed indicator can help identify the dangerous traffic status under fog conditions and then proper ITS technologies can be implemented to enhance traffic safety when the visibility declines. Copyright © 2017 Elsevier Ltd. All rights reserved.

32 CFR 263.10 - Parking.

Code of Federal Regulations, 2010 CFR

2010-07-01

... VEHICLE CONTROL ON CERTAIN DEFENSE MAPPING AGENCY SITES § 263.10 Parking. (a) No person, unless otherwise authorized by a posted traffic sign or directed by a uniformed guard, shall stand or park a motor vehicle: (1) On a sidewalk, lawn, plants or shrubs. (2) Within an intersection or within a crosswalk. (3) Within...

32 CFR 263.10 - Parking.

Code of Federal Regulations, 2011 CFR

2011-07-01

... VEHICLE CONTROL ON CERTAIN DEFENSE MAPPING AGENCY SITES § 263.10 Parking. (a) No person, unless otherwise authorized by a posted traffic sign or directed by a uniformed guard, shall stand or park a motor vehicle: (1) On a sidewalk, lawn, plants or shrubs. (2) Within an intersection or within a crosswalk. (3) Within...

Development of criteria and guidelines for installing, operating, and removing TxDOT ramp control signals.

DOT National Transportation Integrated Search

2009-05-01

The Texas Department of Transportation (TxDOT) uses ramp control signals (also called ramp meters or : flow signals) to control the rate at which vehicles enter the freeway. This helps TxDOT (1) promote a more : consistent and uniform flow of traffic...

23 CFR 1235.7 - Parking space design, construction, and designation.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 23 Highways 1 2011-04-01 2011-04-01 false Parking space design, construction, and designation. 1235.7 Section 1235.7 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GUIDELINES UNIFORM SYSTEM FOR PARKING FOR PERSONS WITH DISABILITIES § 1235.7 Parking space design,...

23 CFR 1200.62 - Pre-2013 fiscal year grants.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 23 Highways 1 2014-04-01 2014-04-01 false Pre-2013 fiscal year grants. 1200.62 Section 1200.62 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PROCEDURES FOR STATE HIGHWAY SAFETY PROGRAMS UNIFORM PROCEDURES FOR STATE HIGHWAY SAFETY GRANT PROGRAMS Special Provisions for...

23 CFR 1200.62 - Pre-2013 fiscal year grants.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 23 Highways 1 2013-04-01 2013-04-01 false Pre-2013 fiscal year grants. 1200.62 Section 1200.62 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PROCEDURES FOR STATE HIGHWAY SAFETY PROGRAMS UNIFORM PROCEDURES FOR STATE HIGHWAY SAFETY GRANT PROGRAMS Special Provisions for...

23 CFR Appendix B to Part 1200 - HIGHWAY SAFETY PROGRAM COST SUMMARY (HS-217)

Code of Federal Regulations, 2013 CFR

2013-04-01

... 23 Highways 1 2013-04-01 2013-04-01 false HIGHWAY SAFETY PROGRAM COST SUMMARY (HS-217) B APPENDIX B TO PART 1200 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PROCEDURES FOR STATE HIGHWAY SAFETY PROGRAMS UNIFORM PROCEDURES FOR...

23 CFR Appendix B to Part 1200 - Highway Safety Program Cost Summary (HS-217)

Code of Federal Regulations, 2014 CFR

2014-04-01

... 23 Highways 1 2014-04-01 2014-04-01 false Highway Safety Program Cost Summary (HS-217) B Appendix B to Part 1200 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PROCEDURES FOR STATE HIGHWAY SAFETY PROGRAMS UNIFORM PROCEDURES FOR...

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

Code of Federal Regulations, 2010 CFR

2010-04-01

... uniformed law enforcement officer and marked law enforcement vehicle in view of motorized traffic on a... and other contingencies. (e) Work Vehicles and Equipment. In addition to addressing risks to workers... contractor's choice of work scheduling and methodology; (6) For Lump Sum items, a contingency provision...

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...

Land use and traffic congestion.

DOT National Transportation Integrated Search

2012-03-01

"The study investigated the link between land use, travel behavior, and traffic congestion. Popular wisdom : suggests that higher-density development patterns may be beneficial in reducing private vehicle dependency : and use, which if true, could ho...

Heterogeneity Index for the Assessment of Relationship Between Land Use Pattern and Road Traffic Congestion in Apapa-Oworoshoki Express way, Lagos Metropolis

NASA Astrophysics Data System (ADS)

Alaigba, D. B.; Soumah, M.; Banjo, M. O.

2017-05-01

The problem of urban mobility is complicated by traffic delay, resulting from poor planning, high population density and poor condition of roads within urban spaces. This study assessed traffic congestion resulting from differential contribution made by various land-uses along Apapa-Oworoshoki expressway in Lagos metropolis. The data for this study was from both primary and secondary sources; GPS point data was collected at selected points for traffic volume count; observation of the nature of vehicular traffic congestion, and land use types along the corridor. Existing data on traffic count along the corridor, connectivity map and land use map sourced from relevant authorities were acquired. Traffic congestion within the area was estimated using volume capacity ratio (V/C). Heterogeneity Index was developed and used to quantify the percentage contribution to traffic volume from various land-use categories. Analytical Hierarchical Processing (AHP) and knowledge-based weighting were used to rank the importance of different heterogeneity indices. Results showed significant relationship between the degree of heterogeneity of the land use pattern and road traffic congestion. Volume Capacity Ratio computed revealed that the route corridor exceeds its designed capacity in the southward direction between the hours of 8am and 12pm on working days. Five major nodes were analyzed along the corridor, and were all above the expected Passenger Car Unit (PCU), these are "Oshodi" 15 %, "Airport junction" 10 %, "Cele bus stop" 21 %, "Mile 2" 14 %, "Berger" 15 % and "Tincan bus stop" 33 % indicating heavy traffic congestion.

Analysis of Child-related Road Traffic Accidents in Vietnam

NASA Astrophysics Data System (ADS)

Vu, Anh Tuan; Nguyen, Dinh Vinh Man

2018-04-01

In recent years, the number of road traffic accidents, fatalities and injuries have been decreasing, but the figures of children road traffic accidents have been increasing in Ho Chi Minh City of Vietnam. This fact strongly calls for implementing effective solutions to improve traffic safety for children by the local government. This paper presents the trends, patterns and causes of road traffic accidents involving children based on the analysis of road traffic accident data over the period 2010-2015 and the video-based observations of road traffic law violations at 15 typical school gates and 10 typical roads. The results could be useful for the city government to formulate solutions to effectively improve traffic safety for children in Ho Chi Minh City and other cities in Vietnam.

Appropriate time scales for nonlinear analyses of deterministic jump systems

NASA Astrophysics Data System (ADS)

Suzuki, Tomoya

2011-06-01

In the real world, there are many phenomena that are derived from deterministic systems but which fluctuate with nonuniform time intervals. This paper discusses the appropriate time scales that can be applied to such systems to analyze their properties. The financial markets are an example of such systems wherein price movements fluctuate with nonuniform time intervals. However, it is common to apply uniform time scales such as 1-min data and 1-h data to study price movements. This paper examines the validity of such time scales by using surrogate data tests to ascertain whether the deterministic properties of the original system can be identified from uniform sampled data. The results show that uniform time samplings are often inappropriate for nonlinear analyses. However, for other systems such as neural spikes and Internet traffic packets, which produce similar outputs, uniform time samplings are quite effective in extracting the system properties. Nevertheless, uniform samplings often generate overlapping data, which can cause false rejections of surrogate data tests.

Analysis of Spatio-Temporal Traffic Patterns Based on Pedestrian Trajectories

NASA Astrophysics Data System (ADS)

Busch, S.; Schindler, T.; Klinger, T.; Brenner, C.

2016-06-01

For driver assistance and autonomous driving systems, it is essential to predict the behaviour of other traffic participants. Usually, standard filter approaches are used to this end, however, in many cases, these are not sufficient. For example, pedestrians are able to change their speed or direction instantly. Also, there may be not enough observation data to determine the state of an object reliably, e.g. in case of occlusions. In those cases, it is very useful if a prior model exists, which suggests certain outcomes. For example, it is useful to know that pedestrians are usually crossing the road at a certain location and at certain times. This information can then be stored in a map which then can be used as a prior in scene analysis, or in practical terms to reduce the speed of a vehicle in advance in order to minimize critical situations. In this paper, we present an approach to derive such a spatio-temporal map automatically from the observed behaviour of traffic participants in everyday traffic situations. In our experiments, we use one stationary camera to observe a complex junction, where cars, public transportation and pedestrians interact. We concentrate on the pedestrians trajectories to map traffic patterns. In the first step, we extract trajectory segments from the video data. These segments are then clustered in order to derive a spatial model of the scene, in terms of a spatially embedded graph. In the second step, we analyse the temporal patterns of pedestrian movement on this graph. We are able to derive traffic light sequences as well as the timetables of nearby public transportation. To evaluate our approach, we used a 4 hour video sequence. We show that we are able to derive traffic light sequences as well as time tables of nearby public transportation.

Characterizing traffic under uncertain disruptions : an experimental approach.

DOT National Transportation Integrated Search

2013-03-01

The objective of the research is to study long-term traffic patterns under uncertain disruptions using : data collected from human subjects who simultaneously make route choices in controlled PC-based : laboratory experiments. Uncertain disruptions t...

Conduct urban agglomeration with the baton of transportation.

DOT National Transportation Integrated Search

2013-12-01

A key indicator of traffic activity patterns is commuting distance. Shorter commuting distances yield less traffic, fewer emissions, : and lower energy consumption. This study develops a spatial error seemingly unrelated regression model to investiga...

Calibration of CORSIM models under saturated traffic flow conditions.

DOT National Transportation Integrated Search

2013-09-01

This study proposes a methodology to calibrate microscopic traffic flow simulation models. : The proposed methodology has the capability to calibrate simultaneously all the calibration : parameters as well as demand patterns for any network topology....

Physiological stress in air traffic controllers : a review.

DOT National Transportation Integrated Search

1982-08-01

Ten years of research on physiological stress in air traffic control specialists (ATCS's) is reviewed. Data were derived from 20 tasks involving the experimental variables of workload, shift-rotation patterns, and automation. : Laboratories at the Ci...

A hybrid optical switch architecture to integrate IP into optical networks to provide flexible and intelligent bandwidth on demand for cloud computing

NASA Astrophysics Data System (ADS)

Yang, Wei; Hall, Trevor J.

2013-12-01

The Internet is entering an era of cloud computing to provide more cost effective, eco-friendly and reliable services to consumer and business users. As a consequence, the nature of the Internet traffic has been fundamentally transformed from a pure packet-based pattern to today's predominantly flow-based pattern. Cloud computing has also brought about an unprecedented growth in the Internet traffic. In this paper, a hybrid optical switch architecture is presented to deal with the flow-based Internet traffic, aiming to offer flexible and intelligent bandwidth on demand to improve fiber capacity utilization. The hybrid optical switch is capable of integrating IP into optical networks for cloud-based traffic with predictable performance, for which the delay performance of the electronic module in the hybrid optical switch architecture is evaluated through simulation.

Queuing theory models for computer networks

NASA Technical Reports Server (NTRS)

Galant, David C.

1989-01-01

A set of simple queuing theory models which can model the average response of a network of computers to a given traffic load has been implemented using a spreadsheet. The impact of variations in traffic patterns and intensities, channel capacities, and message protocols can be assessed using them because of the lack of fine detail in the network traffic rates, traffic patterns, and the hardware used to implement the networks. A sample use of the models applied to a realistic problem is included in appendix A. Appendix B provides a glossary of terms used in this paper. This Ames Research Center computer communication network is an evolving network of local area networks (LANs) connected via gateways and high-speed backbone communication channels. Intelligent planning of expansion and improvement requires understanding the behavior of the individual LANs as well as the collection of networks as a whole.

Early Obstacle Detection and Avoidance for All to All Traffic Pattern in Wireless Sensor Networks

NASA Astrophysics Data System (ADS)

Huc, Florian; Jarry, Aubin; Leone, Pierre; Moraru, Luminita; Nikoletseas, Sotiris; Rolim, Jose

This paper deals with early obstacles recognition in wireless sensor networks under various traffic patterns. In the presence of obstacles, the efficiency of routing algorithms is increased by voluntarily avoiding some regions in the vicinity of obstacles, areas which we call dead-ends. In this paper, we first propose a fast convergent routing algorithm with proactive dead-end detection together with a formal definition and description of dead-ends. Secondly, we present a generalization of this algorithm which improves performances in all to many and all to all traffic patterns. In a third part we prove that this algorithm produces paths that are optimal up to a constant factor of 2π + 1. In a fourth part we consider the reactive version of the algorithm which is an extension of a previously known early obstacle detection algorithm. Finally we give experimental results to illustrate the efficiency of our algorithms in different scenarios.

75 FR 74128 - Manual on Uniform Traffic Control Devices (MUTCD) Compliance Dates

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-30

... notice asks for responses to a series of questions about compliance dates, their benefits and economic...: For questions about the program discussed herein, contact Mr. Hari Kalla, MUTCD Team Leader, FHWA Office of Operations, (202) 366-5915, or via e-mail at [email protected] . For legal questions, please...

23 CFR 1200.60 - Fiscal year 2013 Section 402 grants.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 23 Highways 1 2013-04-01 2013-04-01 false Fiscal year 2013 Section 402 grants. 1200.60 Section 1200.60 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PROCEDURES FOR STATE HIGHWAY SAFETY PROGRAMS UNIFORM PROCEDURES FOR STATE HIGHWAY SAFETY GRANT PROGRAMS Special Provisions...

23 CFR 1200.61 - Fiscal year 2013 Section 405 grants.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 23 Highways 1 2013-04-01 2013-04-01 false Fiscal year 2013 Section 405 grants. 1200.61 Section 1200.61 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PROCEDURES FOR STATE HIGHWAY SAFETY PROGRAMS UNIFORM PROCEDURES FOR STATE HIGHWAY SAFETY GRANT PROGRAMS Special Provisions...

23 CFR 1200.60 - Fiscal year 2013 Section 402 grants.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 23 Highways 1 2014-04-01 2014-04-01 false Fiscal year 2013 Section 402 grants. 1200.60 Section 1200.60 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PROCEDURES FOR STATE HIGHWAY SAFETY PROGRAMS UNIFORM PROCEDURES FOR STATE HIGHWAY SAFETY GRANT PROGRAMS Special Provisions...

23 CFR 1200.61 - Fiscal year 2013 Section 405 grants.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 23 Highways 1 2014-04-01 2014-04-01 false Fiscal year 2013 Section 405 grants. 1200.61 Section 1200.61 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PROCEDURES FOR STATE HIGHWAY SAFETY PROGRAMS UNIFORM PROCEDURES FOR STATE HIGHWAY SAFETY GRANT PROGRAMS Special Provisions...

49 CFR 397.73 - Public information and reporting requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... in the form of maps, lists, road signs or some combination thereof. If road signs are used, those signs and their placements must comply with the provisions of the Manual on Uniform Traffic Control Devices, 2 published by the FMCSA, particularly the Hazardous Cargo signs identified as R14-2 and R14-3...

49 CFR 397.73 - Public information and reporting requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... in the form of maps, lists, road signs or some combination thereof. If road signs are used, those signs and their placements must comply with the provisions of the Manual on Uniform Traffic Control Devices, 2 published by the FMCSA, particularly the Hazardous Cargo signs identified as R14-2 and R14-3...

49 CFR 397.73 - Public information and reporting requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... in the form of maps, lists, road signs or some combination thereof. If road signs are used, those signs and their placements must comply with the provisions of the Manual on Uniform Traffic Control Devices, 2 published by the FMCSA, particularly the Hazardous Cargo signs identified as R14-2 and R14-3...

49 CFR 397.73 - Public information and reporting requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... in the form of maps, lists, road signs or some combination thereof. If road signs are used, those signs and their placements must comply with the provisions of the Manual on Uniform Traffic Control Devices, 2 published by the FMCSA, particularly the Hazardous Cargo signs identified as R14-2 and R14-3...

49 CFR 397.73 - Public information and reporting requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... in the form of maps, lists, road signs or some combination thereof. If road signs are used, those signs and their placements must comply with the provisions of the Manual on Uniform Traffic Control Devices, 2 published by the FMCSA, particularly the Hazardous Cargo signs identified as R14-2 and R14-3...

Integration of Weather Avoidance and Traffic Separation

NASA Technical Reports Server (NTRS)

Consiglio, Maria C.; Chamberlain, James P.; Wilson, Sara R.

2011-01-01

This paper describes a dynamic convective weather avoidance concept that compensates for weather motion uncertainties; the integration of this weather avoidance concept into a prototype 4-D trajectory-based Airborne Separation Assurance System (ASAS) application; and test results from a batch (non-piloted) simulation of the integrated application with high traffic densities and a dynamic convective weather model. The weather model can simulate a number of pseudo-random hazardous weather patterns, such as slow- or fast-moving cells and opening or closing weather gaps, and also allows for modeling of onboard weather radar limitations in range and azimuth. The weather avoidance concept employs nested "core" and "avoid" polygons around convective weather cells, and the simulations assess the effectiveness of various avoid polygon sizes in the presence of different weather patterns, using traffic scenarios representing approximately two times the current traffic density in en-route airspace. Results from the simulation experiment show that the weather avoidance concept is effective over a wide range of weather patterns and cell speeds. Avoid polygons that are only 2-3 miles larger than their core polygons are sufficient to account for weather uncertainties in almost all cases, and traffic separation performance does not appear to degrade with the addition of weather polygon avoidance. Additional "lessons learned" from the batch simulation study are discussed in the paper, along with insights for improving the weather avoidance concept. Introduction

Evaluating the Effects of Traffic on Driver Stopping and Turn Signal Use at a Stop Sign: A Systematic Replication

ERIC Educational Resources Information Center

Lebbon, Angela R.; Austin, John; Van Houten, Ron; Malenfant, Louis E.

2007-01-01

The current analyses of observational data found that oncoming traffic substantially affected driver stopping patterns and turn signal use at the target stop sign. The percentage of legal stops and turn signal use by drivers in the presence and absence of traffic was analyzed using a multi-element design. The results showed that legal stops were…

Effects of the amount of feedback information on urban traffic with advanced traveler information system

NASA Astrophysics Data System (ADS)

Chen, Jie; Li, Ming; Jiang, Rui; Hu, Mao-Bin

2017-09-01

In a real traffic system, information feedback has already been proven to be a good way to alleviate traffic jams. However, due to the massive traffic information of real system, the procedure is often difficult in practice. In this paper, we study the effects of the amount of feedback information based on a cellular automaton model of urban traffic. What we found most interesting is that when providing the traffic information of a part of a road to travelers, the performance of the system will be better than that providing the road's full traffic information. From this basis, we can provide more effective routing strategy with less information. We demonstrate that only providing the traffic information of about first half road from upstream to downstream can maximize the traffic capacity of the system. We also give an explanation for these phenomena by studying the distribution pattern of vehicles and the detailed turning environment at the intersections. The effects of the traffic light period are also provided.

Statistics with applications to highway traffic analyses

DOT National Transportation Integrated Search

1952-01-01

The rapid movement of traffic on our streets and highways in ever changing patterns is one of the most familiar andbeneficialphenomenaofour daily lives and atthe sametime one of the most confusing and vexing. The annoyances and even danger experience...

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

DOT National Transportation Integrated Search

2006-08-01

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

A realistic view of the people in air traffic control.

DOT National Transportation Integrated Search

1974-12-01

An overview of research findings on air traffic controllers is presented. Results of personality, aptitude, motivation, interest, and attitude studies are considered in terms of the general pattern of characteristics found to be associated with succe...

Data traffic reduction schemes for Cholesky factorization on asynchronous multiprocessor systems

NASA Technical Reports Server (NTRS)

Naik, Vijay K.; Patrick, Merrell L.

1989-01-01

Communication requirements of Cholesky factorization of dense and sparse symmetric, positive definite matrices are analyzed. The communication requirement is characterized by the data traffic generated on multiprocessor systems with local and shared memory. Lower bound proofs are given to show that when the load is uniformly distributed the data traffic associated with factoring an n x n dense matrix using n to the alpha power (alpha less than or equal 2) processors is omega(n to the 2 + alpha/2 power). For n x n sparse matrices representing a square root of n x square root of n regular grid graph the data traffic is shown to be omega(n to the 1 + alpha/2 power), alpha less than or equal 1. Partitioning schemes that are variations of block assignment scheme are described and it is shown that the data traffic generated by these schemes are asymptotically optimal. The schemes allow efficient use of up to O(n to the 2nd power) processors in the dense case and up to O(n) processors in the sparse case before the total data traffic reaches the maximum value of O(n to the 3rd power) and O(n to the 3/2 power), respectively. It is shown that the block based partitioning schemes allow a better utilization of the data accessed from shared memory and thus reduce the data traffic than those based on column-wise wrap around assignment schemes.

Spatial patterns monitoring of road traffic injuries in Karachi metropolis.

PubMed

Lateef, Muhammad U

2011-06-01

This article aims to assess the pattern of road traffic injuries (RTIs) and fatalities in Karachi metropolis. Assessing the pattern of RTIs in Karachi at this juncture is important for many reasons. The rapid motorisation in the recent years due to the availability of credit has significantly increased the traffic volume of the city. Since then, the roads of Karachi have continuously developed at a rapid pace. This development has come with a high human loss, because the construction of multilevel flyovers, signal-free corridors and the resulting high-speed traffic ultimately increase the severity of injuries. The reasons for this high proportion are inadequate infrastructure, poor enforcement of safety regulations, high crash severity index and greater population of vulnerable road user groups (riders and pedestrians). This research is the first of its kind in the country to have a geocoded database of fatalities and injuries in a geographical information system for the entire city of Karachi. In fact, road crashes are both predictable and preventable. Developing countries should learn from the experience of highly motorised nations to avoid the high burden of RTIs by adopting road safety and prevention measures.

A Holding Function for Conflict Probe Appiications

NASA Technical Reports Server (NTRS)

McNally, Dave; Walton, Joe

2004-01-01

Conflict Alerts for aircraft in holding patterns are often missed or in error due to fact that holding trajectories are not modeled in Conflict Alert or Conflict Probe logic. In addition, a controller in one sector may not know when aircraft are holding in a neighboring sector. These factors can lead to an increased potential for loss of separation while aircraft are flying in holding patterns. A holding function for conflict probe applications has been developed and tested with air traffic data from Fort Worth Center. The holding function automatically determines when an aircraft enters a holding pattern, builds a holding region around the pattern and then probes the region for conflict with other traffic. The operational concept of use assumes that air traffic controllers are very busy during periods when aircraft are in holding and therefore don't have time to manually enter information which defines a holding pattern and activates conflict probing. For this reason, it is important the holding function automatically detect aircraft in holding and compute a holding region for conflict analysis. The controller is then alerted if other aircraft are predicted to fly through the holding region at the holding altitude.

Modelling disease outbreaks in realistic urban social networks

NASA Astrophysics Data System (ADS)

Eubank, Stephen; Guclu, Hasan; Anil Kumar, V. S.; Marathe, Madhav V.; Srinivasan, Aravind; Toroczkai, Zoltán; Wang, Nan

2004-05-01

Most mathematical models for the spread of disease use differential equations based on uniform mixing assumptions or ad hoc models for the contact process. Here we explore the use of dynamic bipartite graphs to model the physical contact patterns that result from movements of individuals between specific locations. The graphs are generated by large-scale individual-based urban traffic simulations built on actual census, land-use and population-mobility data. We find that the contact network among people is a strongly connected small-world-like graph with a well-defined scale for the degree distribution. However, the locations graph is scale-free, which allows highly efficient outbreak detection by placing sensors in the hubs of the locations network. Within this large-scale simulation framework, we then analyse the relative merits of several proposed mitigation strategies for smallpox spread. Our results suggest that outbreaks can be contained by a strategy of targeted vaccination combined with early detection without resorting to mass vaccination of a population.

Switching performance of OBS network model under prefetched real traffic

NASA Astrophysics Data System (ADS)

Huang, Zhenhua; Xu, Du; Lei, Wen

2005-11-01

Optical Burst Switching (OBS) [1] is now widely considered as an efficient switching technique in building the next generation optical Internet .So it's very important to precisely evaluate the performance of the OBS network model. The performance of the OBS network model is variable in different condition, but the most important thing is that how it works under real traffic load. In the traditional simulation models, uniform traffics are usually generated by simulation software to imitate the data source of the edge node in the OBS network model, and through which the performance of the OBS network is evaluated. Unfortunately, without being simulated by real traffic, the traditional simulation models have several problems and their results are doubtable. To deal with this problem, we present a new simulation model for analysis and performance evaluation of the OBS network, which uses prefetched IP traffic to be data source of the OBS network model. The prefetched IP traffic can be considered as real IP source of the OBS edge node and the OBS network model has the same clock rate with a real OBS system. So it's easy to conclude that this model is closer to the real OBS system than the traditional ones. The simulation results also indicate that this model is more accurate to evaluate the performance of the OBS network system and the results of this model are closer to the actual situation.

The Effect of Weather Events on Truck Traffic Patterns Using Fixed and Mobile Traffic Sensors

DOT National Transportation Integrated Search

2017-12-20

Connected vehicle applications related to road weather management and enabling systems are being designed to collect and take advantage of connected vehicle data and information transmissions to increase situational awareness, improve roadway levels ...

Roadway usage patterns : urban case studies - final report

DOT National Transportation Integrated Search

1996-01-01

The Orlando Test Network Study was one of a series of investigations conducted as part of the TravTek operational test of an advanced traveler information and traffic management system (ATIS/ATMS). The TravTek system consisted of the Orlando Traffic ...

Data mining of air traffic control operational errors

DOT National Transportation Integrated Search

2006-01-01

In this paper we present the results of : applying data mining techniques to identify patterns and : anomalies in air traffic control operational errors (OEs). : Reducing the OE rate is of high importance and remains a : challenge in the aviation saf...

An Analysis of fatal traffic crashes in Kentucky and recommended countermeasures.

DOT National Transportation Integrated Search

2005-11-01

The objective of this study were analyze fatal traffic crashes in Kentucky to identify patterns and causes of these crashes and to recommend potential countermeasures. The study included the following areas of analysis: 1) trends in fatal collisions,...

Michigan fatal and serious injury traffic-crash patterns : 1993-1997

DOT National Transportation Integrated Search

1999-01-01

This report details facts and figures relevant to a better understanding of possible causes of and prevention implications for deaths and serious injuries due to traffic crashes in the state of Michigan during the period Junuary 1993 through December...

Michigan fatal and serious injury traffic-crash patterns : 1994-1998

DOT National Transportation Integrated Search

1999-11-01

This report details facts and figures relevant to a better understanding of possible causes of and prevention implications for deaths and serious injuries due to traffic crashes in the state of Michigan during the period January 1994 through December...

Modeling traffic accidents at signalized intersections in the city of Norfolk, VA.

DOT National Transportation Integrated Search

2010-12-31

This study was an attempt to apply a proactive approach using traffic pattern and signalized intersection characteristics to predict accident rates at signalized intersections in a citys arterial network. An earlier analysis of accident data at se...

Traffic speed data imputation method based on tensor completion.

PubMed

Ran, Bin; Tan, Huachun; Feng, Jianshuai; Liu, Ying; Wang, Wuhong

2015-01-01

Traffic speed data plays a key role in Intelligent Transportation Systems (ITS); however, missing traffic data would affect the performance of ITS as well as Advanced Traveler Information Systems (ATIS). In this paper, we handle this issue by a novel tensor-based imputation approach. Specifically, tensor pattern is adopted for modeling traffic speed data and then High accurate Low Rank Tensor Completion (HaLRTC), an efficient tensor completion method, is employed to estimate the missing traffic speed data. This proposed method is able to recover missing entries from given entries, which may be noisy, considering severe fluctuation of traffic speed data compared with traffic volume. The proposed method is evaluated on Performance Measurement System (PeMS) database, and the experimental results show the superiority of the proposed approach over state-of-the-art baseline approaches.

Traffic Speed Data Imputation Method Based on Tensor Completion

PubMed Central

Ran, Bin; Feng, Jianshuai; Liu, Ying; Wang, Wuhong

2015-01-01

Traffic speed data plays a key role in Intelligent Transportation Systems (ITS); however, missing traffic data would affect the performance of ITS as well as Advanced Traveler Information Systems (ATIS). In this paper, we handle this issue by a novel tensor-based imputation approach. Specifically, tensor pattern is adopted for modeling traffic speed data and then High accurate Low Rank Tensor Completion (HaLRTC), an efficient tensor completion method, is employed to estimate the missing traffic speed data. This proposed method is able to recover missing entries from given entries, which may be noisy, considering severe fluctuation of traffic speed data compared with traffic volume. The proposed method is evaluated on Performance Measurement System (PeMS) database, and the experimental results show the superiority of the proposed approach over state-of-the-art baseline approaches. PMID:25866501

Brazilian Road Traffic Fatalities: A Spatial and Environmental Analysis

PubMed Central

de Andrade, Luciano; Vissoci, João Ricardo Nickenig; Rodrigues, Clarissa Garcia; Finato, Karen; Carvalho, Elias; Pietrobon, Ricardo; de Souza, Eniuce Menezes; Nihei, Oscar Kenji; Lynch, Catherine; de Barros Carvalho, Maria Dalva

2014-01-01

Background Road traffic injuries (RTI) are a major public health epidemic killing thousands of people daily. Low and middle-income countries, such as Brazil, have the highest annual rates of road traffic fatalities. In order to improve road safety, this study mapped road traffic fatalities on a Brazilian highway to determine the main environmental factors affecting road traffic fatalities. Methods and Findings Four techniques were utilized to identify and analyze RTI hotspots. We used spatial analysis by points by applying kernel density estimator, and wavelet analysis to identify the main hot regions. Additionally, built environment analysis, and principal component analysis were conducted to verify patterns contributing to crash occurrence in the hotspots. Between 2007 and 2009, 379 crashes were notified, with 466 fatalities on BR277. Higher incidence of crashes occurred on sections of highway with double lanes (ratio 2∶1). The hotspot analysis demonstrated that both the eastern and western regions had higher incidences of crashes when compared to the central region. Through the built environment analysis, we have identified five different patterns, demonstrating that specific environmental characteristics are associated with different types of fatal crashes. Patterns 2 and 4 are constituted mainly by predominantly urban characteristics and have frequent fatal pedestrian crashes. Patterns 1, 3 and 5 display mainly rural characteristics and have higher prevalence of vehicular collisions. In the built environment analysis, the variables length of road in urban area, limited lighting, double lanes roadways, and less auxiliary lanes were associated with a higher incidence of fatal crashes. Conclusions By combining different techniques of analyses, we have identified numerous hotspots and environmental characteristics, which governmental or regulatory agencies could make use to plan strategies to reduce RTI and support life-saving policies. PMID:24498051

Analysis of vehicular traffic flow in the major areas of Kuala Lumpur utilizing open-traffic

NASA Astrophysics Data System (ADS)

Manogaran, Saargunawathy; Ali, Muhammad; Yusof, Kamaludin Mohamad; Suhaili, Ramdhan

2017-09-01

Vehicular traffic congestion occurs when a large number of drivers are overcrowded on the road and the traffic flow does not run smoothly. Traffic congestion causes chaos on the road and interruption to daily activities of users. Time consumed on road give lots of negative effects on productivity, social behavior, environmental and cost to economy. Congestion is worsens and leads to havoc during the emergency such as flood, accidents, road maintenance and etc., where behavior of traffic flow is always unpredictable and uncontrollable. Real-time and historical traffic data are critical inputs for most traffic flow analysis applications. Researcher attempt to predict traffic using simulations as there is no exact model of traffic flow exists due to its high complexity. Open Traffic is an open source platform available for traffic data analysis linked to Open Street Map (OSM). This research is aimed to study and understand the Open Traffic platform. The real-time traffic flow pattern in Kuala Lumpur area was successfully been extracted and analyzed using Open Traffic. It was observed that the congestion occurs on every major road in Kuala Lumpur and most of it owes to the offices and the economic and commercial centers during rush hours. At some roads the congestion occurs at night due to the tourism activities.

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...

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...

Stopping for School Buses. Traffic Laws Commentary Series.

ERIC Educational Resources Information Center

Yaw, E. Eugene

The degree of uniformity among State laws requiring drivers to stop for school buses receiving or discharging children is not such that drivers could reasonably be expected to know these laws. Because of the wide variation of State laws and the inherent vulnerability of school children and of any vehicle stopping on a highway, there can be no…

Impact assessment of incident scene work zone alerts for drivers and workers (INC-ZONE) and incident scene pre-arrival staging guidance for emergency responders (RESP-STG).

DOT National Transportation Integrated Search

2015-05-01

Response, Emergency Staging and Communications, Uniform Management, and Evacuation (R.E.S.C.U.M.E.) is a bundle of applications that targets the improvement of traffic safety and mobility during crashes and other emergencies that affect the highway n...

Mapping the spatial patterns of field traffic and traffic intensity to predict soil compaction risks at the field scale

NASA Astrophysics Data System (ADS)

Duttmann, Rainer; Kuhwald, Michael; Nolde, Michael

2015-04-01

Soil compaction is one of the main threats to cropland soils in present days. In contrast to easily visible phenomena of soil degradation, soil compaction, however, is obscured by other signals such as reduced crop yield, delayed crop growth, and the ponding of water, which makes it difficult to recognize and locate areas impacted by soil compaction directly. Although it is known that trafficking intensity is a key factor for soil compaction, until today only modest work has been concerned with the mapping of the spatially distributed patterns of field traffic and with the visual representation of the loads and pressures applied by farm traffic within single fields. A promising method for for spatial detection and mapping of soil compaction risks of individual fields is to process dGPS data, collected from vehicle-mounted GPS receivers and to compare the soil stress induced by farm machinery to the load bearing capacity derived from given soil map data. The application of position-based machinery data enables the mapping of vehicle movements over time as well as the assessment of trafficking intensity. It also facilitates the calculation of the trafficked area and the modeling of the loads and pressures applied to soil by individual vehicles. This paper focuses on the modeling and mapping of the spatial patterns of traffic intensity in silage maize fields during harvest, considering the spatio-temporal changes in wheel load and ground contact pressure along the loading sections. In addition to scenarios calculated for varying mechanical soil strengths, an example for visualizing the three-dimensional stress propagation inside the soil will be given, using the Visualization Toolkit (VTK) to construct 2D or 3D maps supporting to decision making due to sustainable field traffic management.

Impacts of LED Brightness, Flash Pattern, and Location for Illuminated Pedestrian Traffic Control Device

DOT National Transportation Integrated Search

2015-05-01

Illuminated traffic control devices, such as rectangular rapid-flashing beacons (RRFB), have been shown to increase the number of drivers yielding to crossing pedestrians. There is some concern that the brightness of flashes at or contained within si...

Comparison of Driver Yielding for Three Rapid-flashing Patterns Used with Pedestrian Crossing Signs

DOT National Transportation Integrated Search

2015-05-01

Flashing traffic control devices can help draw drivers attention to the traffic control device and to the area around the device. An example of a device that has resulted in significant improvements in increasing driver yielding to crossing pedest...

Potential of dynamic spectrum allocation in LTE macro networks

NASA Astrophysics Data System (ADS)

Hoffmann, H.; Ramachandra, P.; Kovács, I. Z.; Jorguseski, L.; Gunnarsson, F.; Kürner, T.

2015-11-01

In recent years Mobile Network Operators (MNOs) worldwide are extensively deploying LTE networks in different spectrum bands and utilising different bandwidth configurations. Initially, the deployment is coverage oriented with macro cells using the lower LTE spectrum bands. As the offered traffic (i.e. the requested traffic from the users) increases the LTE deployment evolves with macro cells expanded with additional capacity boosting LTE carriers in higher frequency bands complemented with micro or small cells in traffic hotspot areas. For MNOs it is crucial to use the LTE spectrum assets, as well as the installed network infrastructure, in the most cost efficient way. The dynamic spectrum allocation (DSA) aims at (de)activating the available LTE frequency carriers according to the temporal and spatial traffic variations in order to increase the overall LTE system performance in terms of total network capacity by reducing the interference. This paper evaluates the DSA potential of achieving the envisaged performance improvement and identifying in which system and traffic conditions the DSA should be deployed. A self-optimised network (SON) DSA algorithm is also proposed and evaluated. The evaluations have been carried out in a hexagonal and a realistic site-specific urban macro layout assuming a central traffic hotspot area surrounded with an area of lower traffic with a total size of approximately 8 × 8 km2. The results show that up to 47 % and up to 40 % possible DSA gains are achievable with regards to the carried system load (i.e. used resources) for homogenous traffic distribution with hexagonal layout and for realistic site-specific urban macro layout, respectively. The SON DSA algorithm evaluation in a realistic site-specific urban macro cell deployment scenario including realistic non-uniform spatial traffic distribution shows insignificant cell throughput (i.e. served traffic) performance gains. Nevertheless, in the SON DSA investigations, a gain of up to 25 % has been observed when analysing the resource utilisation in the non-hotspot cells.

Evolving optimised decision rules for intrusion detection using particle swarm paradigm

NASA Astrophysics Data System (ADS)

Sivatha Sindhu, Siva S.; Geetha, S.; Kannan, A.

2012-12-01

The aim of this article is to construct a practical intrusion detection system (IDS) that properly analyses the statistics of network traffic pattern and classify them as normal or anomalous class. The objective of this article is to prove that the choice of effective network traffic features and a proficient machine-learning paradigm enhances the detection accuracy of IDS. In this article, a rule-based approach with a family of six decision tree classifiers, namely Decision Stump, C4.5, Naive Baye's Tree, Random Forest, Random Tree and Representative Tree model to perform the detection of anomalous network pattern is introduced. In particular, the proposed swarm optimisation-based approach selects instances that compose training set and optimised decision tree operate over this trained set producing classification rules with improved coverage, classification capability and generalisation ability. Experiment with the Knowledge Discovery and Data mining (KDD) data set which have information on traffic pattern, during normal and intrusive behaviour shows that the proposed algorithm produces optimised decision rules and outperforms other machine-learning algorithm.

Emotional states of drivers and the impact on speed, acceleration and traffic violations - a simulator study.

PubMed

Roidl, Ernst; Frehse, Berit; Höger, Rainer

2014-09-01

Maladjusted driving, such as aggressive driving and delayed reactions, is seen as one cause of traffic accidents. Such behavioural patterns could be influenced by strong emotions in the driver. The causes of emotions in traffic are divided into two distinct classes: personal factors and properties of the specific driving situation. In traffic situations, various appraisal factors are responsible for the nature and intensity of experienced emotions. These include whether another driver was accountable, whether goals were blocked and whether progress and safety were affected. In a simulator study, seventy-nine participants took part in four traffic situations which each elicited a different emotion. Each situation had critical elements (e.g. slow car, obstacle on the street) based on combinations of the appraisal factors. Driving parameters such as velocity, acceleration, and speeding, together with the experienced emotions, were recorded. Results indicate that anger leads to stronger acceleration and higher speeds even for 2 km beyond the emotion-eliciting event. Anxiety and contempt yielded similar but weaker effects, yet showed the same negative and dangerous driving pattern as anger. Fright correlated with stronger braking momentum and lower speeds directly after the critical event. Copyright © 2014. Published by Elsevier Ltd.

CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: A Realistic Cellular Automaton Model for Synchronized Traffic Flow

NASA Astrophysics Data System (ADS)

Zhao, Bo-Han; Hu, Mao-Bin; Jiang, Rui; Wu, Qing-Song

2009-11-01

A cellular automaton model is proposed to consider the anticipation effect in drivers' behavior. It is shown that the anticipation effect can be one of the origins of synchronized traffic flow. With anticipation effect, the congested traffic flow simulated by the model exhibits the features of synchronized flow. The spatiotemporal patterns induced by an on-ramp are also consistent with the three-phase traffic theory. Since the origin of synchronized flow is still controversial, our work can shed some light on the mechanism of synchronized flow.

Order and disorder in traffic and self-driven many-particle systems

NASA Astrophysics Data System (ADS)

Helbing, Dirk

2002-07-01

During the last decade, physicists have identified various spatio-temporal patterns of motion in vehicle and pedestrian traffic. Moreover, by applying and extending methods from statistical physics and non-linear dynamics, these have been successfully explained by means of self-driven many-particle models. Some of the questions now understood are the following: Why are vehicles sometimes stopped by so-called "phantom traffic jams," although they all like to drive fast? What are the mechanisms behind stop-and-go traffic? Why are there several different kinds of congestion, and how are they related? Why do most traffic jams occur considerably before the road capacity is reached? Can a temporary reduction of the traffic volume cause a lasting traffic jam? What is the origin of fluctuations in traffic systems and which consequences do they have? Why do pedestrians moving in opposite directions normally organize in lanes, while nervous crowds are "freezing by heating?" Why do panicking pedestrians produce dangerous deadlocks?

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...

A comparison of the job attitudes and interest patterns of air traffic and airway facility personnel.

DOT National Transportation Integrated Search

1979-03-01

Air traffic control specialists (ATCSs) and airway facility technicians (AFTs) were compared on measures of job attitudes and interests. A total of 792 ATCSs and 2,366 AFTs completed the Strong Vocational Interest Blank (SVIB) and questionnaires conc...

Understanding characteristics in multivariate traffic flow time series from complex network structure

NASA Astrophysics Data System (ADS)

Yan, Ying; Zhang, Shen; Tang, Jinjun; Wang, Xiaofei

2017-07-01

Discovering dynamic characteristics in traffic flow is the significant step to design effective traffic managing and controlling strategy for relieving traffic congestion in urban cities. A new method based on complex network theory is proposed to study multivariate traffic flow time series. The data were collected from loop detectors on freeway during a year. In order to construct complex network from original traffic flow, a weighted Froenius norm is adopt to estimate similarity between multivariate time series, and Principal Component Analysis is implemented to determine the weights. We discuss how to select optimal critical threshold for networks at different hour in term of cumulative probability distribution of degree. Furthermore, two statistical properties of networks: normalized network structure entropy and cumulative probability of degree, are utilized to explore hourly variation in traffic flow. The results demonstrate these two statistical quantities express similar pattern to traffic flow parameters with morning and evening peak hours. Accordingly, we detect three traffic states: trough, peak and transitional hours, according to the correlation between two aforementioned properties. The classifying results of states can actually represent hourly fluctuation in traffic flow by analyzing annual average hourly values of traffic volume, occupancy and speed in corresponding hours.

Climate uniformity: its influence on team communication quality, task conflict, and team performance.

PubMed

González-Romá, Vicente; Hernández, Ana

2014-11-01

We investigated whether climate uniformity (the pattern of climate perceptions of organizational support within the team) is related to task conflict, team communication quality, and team performance. We used a sample composed of 141 bank branches and collected data at 3 time points. The results obtained showed that, after controlling for aggregate team climate, climate strength, and their interaction, a type of nonuniform climate pattern (weak dissimilarity) was directly related to task conflict and team communication quality. Teams with weak dissimilarity nonuniform patterns tended to show higher levels of task conflict and lower levels of team communication quality than teams with uniform climate patterns. The relationship between weak dissimilarity patterns and team performance was fully mediated by team communication quality. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

Ultimate intra-wafer critical dimension uniformity control by using lithography and etch tool corrections

NASA Astrophysics Data System (ADS)

Kubis, Michael; Wise, Rich; Reijnen, Liesbeth; Viatkina, Katja; Jaenen, Patrick; Luca, Melisa; Mernier, Guillaume; Chahine, Charlotte; Hellin, David; Kam, Benjamin; Sobieski, Daniel; Vertommen, Johan; Mulkens, Jan; Dusa, Mircea; Dixit, Girish; Shamma, Nader; Leray, Philippe

2016-03-01

With shrinking design rules, the overall patterning requirements are getting aggressively tighter. For the 7-nm node and below, allowable CD uniformity variations are entering the Angstrom region (ref [1]). Optimizing inter- and intra-field CD uniformity of the final pattern requires a holistic tuning of all process steps. In previous work, CD control with either litho cluster or etch tool corrections has been discussed. Today, we present a holistic CD control approach, combining the correction capability of the etch tool with the correction capability of the exposure tool. The study is done on 10-nm logic node wafers, processed with a test vehicle stack patterning sequence. We include wafer-to-wafer and lot-to-lot variation and apply optical scatterometry to characterize the fingerprints. Making use of all available correction capabilities (lithography and etch), we investigated single application of exposure tool corrections and of etch tool corrections as well as combinations of both to reach the lowest CD uniformity. Results of the final pattern uniformity based on single and combined corrections are shown. We conclude on the application of this holistic lithography and etch optimization to 7nm High-Volume manufacturing, paving the way to ultimate within-wafer CD uniformity control.

Development of kinks in car-following models

NASA Astrophysics Data System (ADS)

Kurtze, Douglas A.

2017-03-01

Many car-following models of traffic flow admit the possibility of absolute stability, a situation in which uniform traffic flow at any spacing is linearly stable. Near the threshold of absolute stability, these models can often be reduced to a modified Korteweg-deVries (mKdV) equation plus small corrections. The hyperbolic-tangent "kink" solutions of the mKdV equation are usually of particular interest, as they represent transition zones between regions of different traffic spacings. Solvability analysis is believed to show that only a single member of the one-parameter family of kink solutions is preserved by the correction terms, and this is interpreted as a kind of selection. We show, however, that the usual solvability calculation rests on an unstated, unjustified assumption, and that without this assumption it merely gives a first-order correction to the relation between the traffic spacings far behind and far ahead of the kink, rather than any kind of "selection" criterion for the family of kink solutions. On the other hand, we display a two-parameter family of traveling wave solutions of the mKdV equation, which describe regions of one traffic spacing embedded in traffic of a different spacing; this family includes the kink solutions as a limiting case. We carry out a multiple-time-scales calculation and find conditions under which the inclusions decay, conditions that lead to a selected inclusion, and conditions for which the inclusion evolves into a pair of kinks.

Particles from wood smoke and traffic induce differential pro-inflammatory response patterns in co-cultures

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

Kocbach, Anette; Herseth, Jan Inge; Lag, Marit

2008-10-15

The inflammatory potential of particles from wood smoke and traffic has not been well elucidated. In this study, a contact co-culture of monocytes and pneumocytes was exposed to 10-40 {mu}g/cm{sup 2} of particles from wood smoke and traffic for 12, 40 and 64 h to determine their influence on pro-inflammatory cytokine release (TNF-{alpha}, IL-1, IL-6, IL-8) and viability. To investigate the role of organic constituents in cytokine release the response to particles, their organic extracts and the washed particles were compared. Antagonists were used to investigate source-dependent differences in intercellular signalling (TNF-{alpha}, IL-1). The cytotoxicity was low after exposure tomore » particles from both sources. However, wood smoke, and to a lesser degree traffic-derived particles, induced a reduction in cell number, which was associated with the organic fraction. The release of pro-inflammatory cytokines was similar for both sources after 12 h, but traffic induced a greater release than wood smoke particles with increasing exposure time. The organic fraction accounted for the majority of the cytokine release induced by wood smoke, whereas the washed traffic particles induced a stronger response than the corresponding organic extract. TNF-{alpha} and IL-1 antagonists reduced the release of IL-8 induced by particles from both sources. In contrast, the IL-6 release was only reduced by the IL-1 antagonist during exposure to traffic-derived particles. In summary, particles from wood smoke and traffic induced differential pro-inflammatory response patterns with respect to cytokine release and cell number. Moreover, the influence of the organic particle fraction and intercellular signalling on the pro-inflammatory response seemed to be source-dependent.« less

Polycyclic aromatic hydrocarbons (PAHs) concentration levels, pattern, source identification and soil toxicity assessment in urban traffic soil of Dhanbad, India.

PubMed

Suman, Swapnil; Sinha, Alok; Tarafdar, Abhrajyoti

2016-03-01

Present study was carried out to assess and understand potential health risk and to examine the impact of vehicular traffic on the contamination status of urban traffic soils in Dhanbad City with respect to polycyclic aromatic hydrocarbons (PAHs). Eight urban traffic sites and two control/rural site surface soils were analyzed and the contents of 13 priority PAHs was determined. Total PAH concentration at traffic sites ranged from 1.019 μg g(-1) to 10.856 μg g(-1) with an average value of 3.488 μg g(-1). At control/rural site, average concentration of total PAHs was found to be 0.640 μg g(-1). PAH pattern was dominated by four- and five-ring PAHs (contributing >50% to the total PAHs) at all the eight traffic sites. On the other hand, rural soil showed a predominance of low molecular weight three-ring PAHs (contributing >30% to the total PAHs). Indeno[123-cd]pyrene/benz[ghi]perylene (IP/BgP) ratio indicated that PAH load at the traffic sites is predominated by the gasoline-driven vehicles. The ratio of Ant/(Ant+Phe) varied from 0.03 to 0.44, averaging 0.10; Fla/(Fla+Pyr) from 0.39 to 0.954, averaging 0.52; BaA/(BaA+Chry) from 0.156 to 0.60, averaging 0.44; and IP/(IP+BgP) from 0.176 to 0.811, averaging 0.286. The results indicated that vehicular emission was the major source for PAHs contamination with moderate effect of coal combustion and biomass combustion. Carcinogenic potency of PAH load in traffic soil was nearly 6.15 times higher as compared to the control/rural soil. Copyright © 2015 Elsevier B.V. All rights reserved.

All Source Sensor Analysis

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

- PNNL, Harold Trease

2012-10-10

ASSA is a software application that processes binary data into summarized index tables that can be used to organize features contained within the data. ASSA's index tables can also be used to search for user specified features. ASSA is designed to organize and search for patterns in unstructured binary data streams or archives, such as video, images, audio, and network traffic. ASSA is basically a very general search engine used to search for any pattern in any binary data stream. It has uses in video analytics, image analysis, audio analysis, searching hard-drives, monitoring network traffic, etc.

A review on the temporal pattern of deer-vehicle accidents: impact of seasonal, diurnal and lunar effects in cervids.

PubMed

Steiner, Wolfgang; Leisch, Friedrich; Hackländer, Klaus

2014-05-01

The increasing number of deer-vehicle-accidents (DVAs) and the resulting economic costs have promoted numerous studies on behavioural and environmental factors which may contribute to the quantity, spatiotemporal distribution and characteristics of DVAs. Contrary to the spatial pattern of DVAs, data of their temporal pattern is scarce and difficult to obtain because of insufficient accuracy in available datasets, missing standardization in data aquisition, legal terms and low reporting rates to authorities. Literature of deer-traffic collisions on roads and railways is reviewed to examine current understanding of DVA temporal trends. Seasonal, diurnal and lunar peak accident periods are identified for deer, although seasonal pattern are not consistent among and within species or regions and data on effects of lunar cycles on DVAs is almost non-existent. Cluster analysis of seasonal DVA data shows nine distinct clusters of different seasonal DVA pattern for cervid species within the reviewed literature. Studies analyzing the relationship between time-related traffic predictors and DVAs yield mixed results. Despite the seasonal dissimilarity, diurnal DVA pattern are comparatively constant in deer, resulting in pronounced DVA peaks during the hours of dusk and dawn frequently described as bimodal crepuscular pattern. Behavioural aspects in activity seem to have the highest impact in DVAs temporal trends. Differences and variations are related to habitat-, climatic- and traffic characteristics as well as effects of predation, hunting and disturbance. Knowledge of detailed temporal DVA pattern is essential for prevention management as well as for the application and evaluation of mitigation measures. Copyright © 2014 Elsevier Ltd. All rights reserved.

Mixed Pattern Matching-Based Traffic Abnormal Behavior Recognition

PubMed Central

Cui, Zhiming; Zhao, Pengpeng

2014-01-01

A motion trajectory is an intuitive representation form in time-space domain for a micromotion behavior of moving target. Trajectory analysis is an important approach to recognize abnormal behaviors of moving targets. Against the complexity of vehicle trajectories, this paper first proposed a trajectory pattern learning method based on dynamic time warping (DTW) and spectral clustering. It introduced the DTW distance to measure the distances between vehicle trajectories and determined the number of clusters automatically by a spectral clustering algorithm based on the distance matrix. Then, it clusters sample data points into different clusters. After the spatial patterns and direction patterns learned from the clusters, a recognition method for detecting vehicle abnormal behaviors based on mixed pattern matching was proposed. The experimental results show that the proposed technical scheme can recognize main types of traffic abnormal behaviors effectively and has good robustness. The real-world application verified its feasibility and the validity. PMID:24605045

Integrated coding-aware intra-ONU scheduling for passive optical networks with inter-ONU traffic

NASA Astrophysics Data System (ADS)

Li, Yan; Dai, Shifang; Wu, Weiwei

2016-12-01

Recently, with the soaring of traffic among optical network units (ONUs), network coding (NC) is becoming an appealing technique for improving the performance of passive optical networks (PONs) with such inter-ONU traffic. However, in the existed NC-based PONs, NC can only be implemented by buffering inter-ONU traffic at the optical line terminal (OLT) to wait for the establishment of coding condition, such passive uncertain waiting severely limits the effect of NC technique. In this paper, we will study integrated coding-aware intra-ONU scheduling in which the scheduling of inter-ONU traffic within each ONU will be undertaken by the OLT to actively facilitate the forming of coding inter-ONU traffic based on the global inter-ONU traffic distribution, and then the performance of PONs with inter-ONU traffic can be significantly improved. We firstly design two report message patterns and an inter-ONU traffic transmission framework as the basis for the integrated coding-aware intra-ONU scheduling. Three specific scheduling strategies are then proposed for adapting diverse global inter-ONU traffic distributions. The effectiveness of the work is finally evaluated by both theoretical analysis and simulations.

Ethical Predispositions to Violate or Obey Traffic Rules and the Mediating Role of Driving Styles.

PubMed

Holman, Andrei C; Popusoi, Simona A

2018-07-04

Traffic law violations are the most important determinants of traffic accidents. This study examined the influence of drivers' ethical perspective on their traffic violations and the mediating role of driving styles in these relationships. A sample of 313 drivers participated in the study. Contrary to expectations, high ethical relativism was found to be associated with fewer aggressive traffic violations. This suggests that the informal normative system that parallels the official traffic regulations is the more salient reference against which drivers usually assess the adequacy of their behaviors, highly relativistic drivers being more willing to also take into consideration the official traffic code in these appraisals. We also found significant interactions between idealism and relativism on both ordinary and aggressive violations. Idealism emerged as a predictor of these violations only in drivers low in relativism. In this group, one's concern about the harm that he/she might cause to other traffic participants induces higher traffic law abidingness. These influences of idealism were mediated by certain driving styles. Drivers' general ethical perspective fosters a specific pattern of driving styles and, consequently, the tendency to commit or to refrain from traffic violations.

Temporal and spatial variation in allocating annual traffic activity across an urban region and implications for air quality assessments

PubMed Central

Batterman, Stuart

2015-01-01

Patterns of traffic activity, including changes in the volume and speed of vehicles, vary over time and across urban areas and can substantially affect vehicle emissions of air pollutants. Time-resolved activity at the street scale typically is derived using temporal allocation factors (TAFs) that allow the development of emissions inventories needed to predict concentrations of traffic-related air pollutants. This study examines the spatial and temporal variation of TAFs, and characterizes prediction errors resulting from their use. Methods are presented to estimate TAFs and their spatial and temporal variability and used to analyze total, commercial and non-commercial traffic in the Detroit, Michigan, U.S. metropolitan area. The variability of total volume estimates, quantified by the coefficient of variation (COV) representing the percentage departure from expected hourly volume, was 21, 33, 24 and 33% for weekdays, Saturdays, Sundays and holidays, respectively. Prediction errors mostly resulted from hour-to-hour variability on weekdays and Saturdays, and from day-to-day variability on Sundays and holidays. Spatial variability was limited across the study roads, most of which were large freeways. Commercial traffic had different temporal patterns and greater variability than noncommercial vehicle traffic, e.g., the weekday variability of hourly commercial volume was 28%. The results indicate that TAFs for a metropolitan region can provide reasonably accurate estimates of hourly vehicle volume on major roads. While vehicle volume is only one of many factors that govern on-road emission rates, air quality analyses would be strengthened by incorporating information regarding the uncertainty and variability of traffic activity. PMID:26688671

Seasonal variation in traffic congestion : a study of three U.S. cities

DOT National Transportation Integrated Search

2008-08-01

Drivers may notice seasonal : changes in patterns of highway : congestion in many urban : areas of the country. These : patterns, however, can be very different for individual cities. : This report looks at congestion patterns over a 3-year period : ...

Ecological Associations of Alcohol Outlets with Underage and Young Adult Injuries

PubMed Central

Gruenewald, Paul J.; Freisthler, Bridget; Remer, Lillian; LaScala, Elizabeth A.; Treno, Andrew J.; Ponicki, William R.

2010-01-01

Objective This paper argues that associations between rates of three specific problems related to alcohol (i.e., accidents, traffic crashes, and assaults) should be differentially related to densities of off-premise outlets among underage youth and young adults based upon age related-patterns of alcohol outlet use. Methods Zip code-level population models assessed local and distal effects of alcohol outlets upon rates of hospital discharges for these outcomes. Results Densities of off-premise alcohol outlets were significantly related to injuries from accidents, assaults, and traffic crashes for both underage youth and young adults. Densities of bars were associated with more assaults and densities of restaurants were associated with more traffic crash injuries for young adults. Conclusions The distribution of alcohol-related injuries relative to alcohol outlets reflect patterns of alcohol outlet use. PMID:20028361

Did liberalising bar hours decrease traffic accidents?

PubMed

Green, Colin P; Heywood, John S; Navarro, Maria

2014-05-01

Legal bar closing times in England and Wales have historically been early and uniform. Recent legislation liberalised closing times with the object of reducing social problems thought associated with drinking to "beat the clock." Indeed, using both difference in difference and synthetic control approaches we show that one consequence of this liberalisation was a decrease in traffic accidents. This decrease is heavily concentrated among younger drivers. Moreover, we provide evidence that the effect was most pronounced in the hours of the week directly affected by the liberalisation: late nights and early mornings on weekends. This evidence survives a series of robustness checks and suggests at least one socially positive consequence of extending bar hours. Copyright © 2014 Elsevier B.V. All rights reserved.

Applications of MICP source for next-generation photomask process

NASA Astrophysics Data System (ADS)

Kwon, Hyuk-Joo; Chang, Byung-Soo; Choi, Boo-Yeon; Park, Kyung H.; Jeong, Soo-Hong

2000-07-01

As critical dimensions of photomask extends into submicron range, critical dimension uniformity, edge roughness, macro loading effect, and pattern slope become tighter than before. Fabrication of photomask relies on the ability to pattern features with anisotropic profile. To improve critical dimension uniformity, dry etcher is one of the solution and inductively coupled plasma (ICP) sources have become one of promising high density plasma sources for dry etcher. In this paper, we have utilized dry etcher system with multi-pole ICP source for Cr etch and MoSi etch and have investigated critical dimension uniformity, slope, and defects. We will present dry etch process data by process optimization of newly designed dry etcher system. The designed pattern area is 132 by 132 mm2 with 23 by 23 matrix test patterns. 3 (sigma) of critical dimension uniformity is below 12 nm at 0.8 - 3.0 micrometers . In most cases, we can obtain zero defect masks which is operated by face- down loading.

An E-plane analysis of aperture-matched horn antennas using the moment method and the uniform geometrical theory of diffraction

NASA Technical Reports Server (NTRS)

Heedy, D. J.; Burnside, W. D.

1984-01-01

The moment method and the uniform geometrical theory of diffraction are utilized to obtain two separate solutions for the E-plane field pattern of an aperture-matched horn antenna. This particular horn antenna consists of a standard pyramidal horn with the following modifications: a rolled edge section attached to the aperture edges and a curved throat section. The resulting geometry provides significantly better performance in terms of the pattern, impedance, and frequency characteristics than normally obtainable. The moment method is used to calculate the E-plane pattern and BSWR of the antenna. However, at higher frequencies, large amounts of computation time are required. The uniform geometrical theory of diffraction provides a quick and efficient high frequency solution for the E-plane field pattern. In fact, the uniform geometrical theory of diffraction may be used to initially design the antenna; then, the moment method may be applied to fine tune the design. This procedure has been successfully applied to a compact range feed design.

Identification of brake wear particles and derivation of a quantitative tracer for brake dust at a major road

NASA Astrophysics Data System (ADS)

Gietl, Johanna K.; Lawrence, Roy; Thorpe, Alistair J.; Harrison, Roy M.

2010-01-01

Traffic-generated air pollutant emissions can be classified into exhaust and non-exhaust emissions. Increased attention is focussing on non-exhaust emissions as exhaust emissions are progressively limited by regulations. To characterise metal-rich emission from abrasion processes, size-segregated analysis of atmospheric aerosol particles sampled with micro-orifice uniform deposit impactors (MOUDI) in March 2007 in London was performed. The samples were collected at a roadside and a background site and were analysed for Al, Ba, Cu, Fe, Sb, Ti, V, Zn, Ca 2+, K +, Mg 2+, Na +, and NH 4+. Most components showed a clear roadside increment, which was evident as a higher mass concentration and a change in the size distribution. In particular, Fe, Cu, Ba, and Sb correlated highly, indicative of a common traffic-related source. Using complementary information on the fleet composition, vehicle number and average speed, the brake wear emission was calculated using the EMEP/CORINAIR emission database. The total PM 10 and barium emission of the traffic was determined by ratio to NO x whose source strength was estimated from published emission factors. Barium was found to comprise 1.1% of brake wear (PM 10) particles from the traffic fleet as a whole, allowing its use as a quantitative tracer of brake wear emissions at other traffic-influenced sites.

Microscale traffic simulation and emission estimation in a heavily trafficked roundabout in Madrid (Spain).

PubMed

Quaassdorff, Christina; Borge, Rafael; Pérez, Javier; Lumbreras, Julio; de la Paz, David; de Andrés, Juan Manuel

2016-10-01

This paper presents the evaluation of emissions from vehicle operations in a domain of 300m×300m covering a complex urban roundabout with high traffic density in Madrid. Micro-level simulation was successfully applied to estimate the emissions on a scale of meters. Two programs were used: i) VISSIM to simulate the traffic on the square and to compute velocity-time profiles; and ii) VERSIT+micro through ENVIVER that uses VISSIM outputs to compute the related emissions at vehicle level. Data collection was achieved by a measurement campaign obtaining empirical data of vehicle flows and traffic intensities. Twelve simulations of different traffic situations (scenarios) were conducted, representing different hours from several days in a week and the corresponding NOX and PM10 emissions were estimated. The results show a general reduction on average speeds for higher intensities due to braking-acceleration patterns that contribute to increase the average emission factor and, therefore, the total emissions in the domain, especially on weekdays. The emissions are clearly related to traffic volume, although maximum emission scenario does not correspond to the highest traffic intensity due to congestion and variations in fleet composition throughout the day. These results evidence the potential that local measures aimed at alleviating congestion may have in urban areas to reduce emissions. In general, scenario-averaged emission factors estimated with the VISSIM-VERSIT+micro modelling system fitted well those from the average-speed model COPERT, used as a preliminary validation of the results. The largest deviations between these two models occur in those scenarios with more congestion. The design and resolution of the microscale modelling system allow to reflect the impact of actual traffic conditions on driving patterns and related emissions, making it useful for the design of mitigation measures for specific traffic hot-spots. Copyright © 2016 Elsevier B.V. All rights reserved.

Tourism in protected areas: Disentangling road and traffic effects on intra-guild scavenging processes.

PubMed

Donázar, José Antonio; Ceballos, Olga; Cortés-Avizanda, Ainara

2018-07-15

The expansion of road networks and the increase in traffic have emerged in recent years as key threats to the conservation of biodiversity. This is particularly concerning in many protected areas because the increase of recreational activities requiring the use of vehicles. Effects of roads and traffic within guild scenarios and ecological processes remain however poorly known. Here we examined how road proximity and traffic intensity influence patterns of resource use in an Old-World avian scavenger guild living in a protected natural park in northern Spain. We experimentally placed 130 carcasses at different distances from a scenic road in the centre of the park. Vehicles were recorded by means of traffic counters which revealed that maximum numbers were reached during weekends and holidays and during the middle hours of the day. Avian scavenger attendance at carcasses was recorded by means of camera-traps. Obligated scavengers, Eurasian griffon (Gyps fulvus) and Egyptian vultures (Neophron percnopterus) were frequently observed (59.4% and 37.7% of the consumed carcasses) together with five other facultative scavenger species. We found that the richness (number of species) and the probability of consumption of the resource were reduced the smaller the distance to the road and in days with higher traffic intensity. The same factors affected the probability of presence of all the scavenger species. Moreover, some of them, notably griffon vultures, showed hourly patterns of carcass attendance suggesting avoidance of maximum traffic levels. Our results highlight that roads and traffic would trigger consequences on the structure and functioning of scavenger food webs, which may be particularly concerning in protected areas with remarkable levels of biodiversity. Future regulations at protected areas should couple both traffic and tourist affluence with wildlife conservation. In this way important ecological processes would be preserved while maintaining a good dissemination of natural values. Copyright © 2018 Elsevier B.V. All rights reserved.

A Bayesian approach to traffic light detection and mapping

NASA Astrophysics Data System (ADS)

Hosseinyalamdary, Siavash; Yilmaz, Alper

2017-03-01

Automatic traffic light detection and mapping is an open research problem. The traffic lights vary in color, shape, geolocation, activation pattern, and installation which complicate their automated detection. In addition, the image of the traffic lights may be noisy, overexposed, underexposed, or occluded. In order to address this problem, we propose a Bayesian inference framework to detect and map traffic lights. In addition to the spatio-temporal consistency constraint, traffic light characteristics such as color, shape and height is shown to further improve the accuracy of the proposed approach. The proposed approach has been evaluated on two benchmark datasets and has been shown to outperform earlier studies. The results show that the precision and recall rates for the KITTI benchmark are 95.78 % and 92.95 % respectively and the precision and recall rates for the LARA benchmark are 98.66 % and 94.65 % .

Discovering urban mobility patterns with PageRank based traffic modeling and prediction

NASA Astrophysics Data System (ADS)

Wang, Minjie; Yang, Su; Sun, Yi; Gao, Jun

2017-11-01

Urban transportation system can be viewed as complex network with time-varying traffic flows as links to connect adjacent regions as networked nodes. By computing urban traffic evolution on such temporal complex network with PageRank, it is found that for most regions, there exists a linear relation between the traffic congestion measure at present time and the PageRank value of the last time. Since the PageRank measure of a region does result from the mutual interactions of the whole network, it implies that the traffic state of a local region does not evolve independently but is affected by the evolution of the whole network. As a result, the PageRank values can act as signatures in predicting upcoming traffic congestions. We observe the aforementioned laws experimentally based on the trajectory data of 12000 taxies in Beijing city for one month.

Spatial Copula Model for Imputing Traffic Flow Data from Remote Microwave Sensors.

PubMed

Ma, Xiaolei; Luan, Sen; Du, Bowen; Yu, Bin

2017-09-21

Issues of missing data have become increasingly serious with the rapid increase in usage of traffic sensors. Analyses of the Beijing ring expressway have showed that up to 50% of microwave sensors pose missing values. The imputation of missing traffic data must be urgently solved although a precise solution that cannot be easily achieved due to the significant number of missing portions. In this study, copula-based models are proposed for the spatial interpolation of traffic flow from remote traffic microwave sensors. Most existing interpolation methods only rely on covariance functions to depict spatial correlation and are unsuitable for coping with anomalies due to Gaussian consumption. Copula theory overcomes this issue and provides a connection between the correlation function and the marginal distribution function of traffic flow. To validate copula-based models, a comparison with three kriging methods is conducted. Results indicate that copula-based models outperform kriging methods, especially on roads with irregular traffic patterns. Copula-based models demonstrate significant potential to impute missing data in large-scale transportation networks.

Reducing OR Traffic Using Education, Policy Development, and Communication Technology.

PubMed

Esser, Jennifer; Shrinski, Keonemana; Cady, Rhonda; Belew, John

2016-01-01

A bundled approach to surgical site infection (SSI) prevention strategies includes reducing OR traffic. A nurse-led quality improvement (QI) team sought to reduce OR traffic through education and a process change that included wireless communication technology and policy development. The team measured OR traffic by counting the frequency of door openings per hour in seven surgical suites during 305 surgical procedures conducted during similar 22-week periods before and after the QI project intervention. Door openings decreased significantly (P < 0.05) from an average of 37.8 per hour to 32.8 per hour after the QI project intervention. This suggests that our multifaceted approach reduces OR traffic. The next steps of this project include analyzing automatically captured video to understand OR traffic patterns and expanding education to departments and external personnel frequently present in our surgical suites. Future research evaluating the effectiveness of this OR traffic initiative on SSI incidence is recommended. Copyright © 2016 AORN, Inc. Published by Elsevier Inc. All rights reserved.

Visualizations of Travel Time Performance Based on Vehicle Reidentification Data

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

Young, Stanley Ernest; Sharifi, Elham; Day, Christopher M.

This paper provides a visual reference of the breadth of arterial performance phenomena based on travel time measures obtained from reidentification technology that has proliferated in the past 5 years. These graphical performance measures are revealed through overlay charts and statistical distribution as revealed through cumulative frequency diagrams (CFDs). With overlays of vehicle travel times from multiple days, dominant traffic patterns over a 24-h period are reinforced and reveal the traffic behavior induced primarily by the operation of traffic control at signalized intersections. A cumulative distribution function in the statistical literature provides a method for comparing traffic patterns from variousmore » time frames or locations in a compact visual format that provides intuitive feedback on arterial performance. The CFD may be accumulated hourly, by peak periods, or by time periods specific to signal timing plans that are in effect. Combined, overlay charts and CFDs provide visual tools with which to assess the quality and consistency of traffic movement for various periods throughout the day efficiently, without sacrificing detail, which is a typical byproduct of numeric-based performance measures. These methods are particularly effective for comparing before-and-after median travel times, as well as changes in interquartile range, to assess travel time reliability.« less

Costs of Limiting Route Optimization to Published Waypoints in the Traffic Aware Planner

NASA Technical Reports Server (NTRS)

Karr, David A.; Vivona, Robert A.; Wing, David J.

2013-01-01

The Traffic Aware Planner (TAP) is an airborne advisory tool that generates optimized, traffic-avoiding routes to support the aircraft crew in making strategic reroute requests to Air Traffic Control (ATC). TAP is derived from a research-prototype self-separation tool, the Autonomous Operations Planner (AOP), in which optimized route modifications that avoid conflicts with traffic and weather, using waypoints at explicit latitudes and longitudes (a technique supported by self-separation concepts), are generated by maneuver patterns applied to the existing route. For use in current-day operations in which trajectory changes must be requested from ATC via voice communication, TAP produces optimized routes described by advisories that use only published waypoints prior to a reconnection waypoint on the existing route. We describe how the relevant algorithms of AOP have been modified to implement this requirement. The modifications include techniques for finding appropriate published waypoints in a maneuver pattern and a method for combining the genetic algorithm of AOP with an exhaustive search of certain types of advisory. We demonstrate methods to investigate the increased computation required by these techniques and to estimate other costs (measured in terms such as time to destination and fuel burned) that may be incurred when only published waypoints are used.

Spatial and temporal trends from an air quality sensor network near a heavily trafficked intersection

NASA Astrophysics Data System (ADS)

Orlando, P.; Vo, D.; Giossi, C.; George, L.

2017-12-01

With the world-wide increase in urbanization and the increasing usage of combustion vehicles in urban areas, traffic-related air pollution is a growing health hazard. However, there are limited studies that examine the spatial and temporal impacts of traffic-related pollutants within cities. In particular, there are few studies that look at traffic management and its potential for pollution mitigation. In a previous study we examined roadway pollution and traffic parameters with one roadway station instrumented with standard measurement instruments. With the advent of low-cost air pollution sensors, we have expanded our work by observing multiple sites within a neighborhood to understand spatial and temporal exposures. We have deployed a high-density sensor network around urban arterial corridors in SE Portland, Oregon. This network consisted of ten nodes measuring CO, NO, NO2 and O3, and ten nodes measuring CO, CO2, VOC and PM2.5. The co-location of standard measurement instruments provided insight towards the utility of our low-cost sensor network, as the different nodes varied in cost, and potentially in quality. We have identified near-real-time temporal trends and local-scale spatial patterns during the summer of 2017. Meteorological and traffic data were included to further characterize these patterns, exploring the potential for pollution mitigation.

Factors Affecting Road Traffic Accident in Batu Pahat, Johor, Malaysia

NASA Astrophysics Data System (ADS)

Che-Him, Norziha; Roslan, Rozaini; Saifullah Rusiman, Mohd; Khalid, Kamil; Ghazali Kamardan, M.; Azbi Arobi, Farquis; Mohamad, Nazeera

2018-04-01

A road traffic accident resulted from the combination of factors related to the few components of the system involving environment, roads, road users, vehicles and the interaction between those systems. Road traffic accident (RTA) in Malaysia recorded as the highest fatality rate (per 100,000 population) among the ASEAN countries. In 2016, more than half of million cases accident recorded with more than 7,000 people were killed. Therefore, the RTA is one of the most critical issue in Malaysia even become the worldwide burden to authority. Generally, driving is a complex process which involves movement of a vehicle by either a computer or human controller. However, failure to control and coordinate will contribute to an accident. The objective of this study is to identify the pattern of accident in Johor Malaysia and to examine the relationship between the number of accident and the types of vehicles and roads. The results could help the government to recognise the different patterns, types of vehicles and roads that show major factors in the increasing of road traffic accident in Malaysia.

Patterns of Alcohol Policy Enforcement Activities among Local Law Enforcement Agencies: A Latent Class Analysis

PubMed Central

Erickson, Darin J.; Rutledge, Patricia C.; Lenk, Kathleen M.; Nelson, Toben F.; Jones-Webb, Rhonda; Toomey, Traci L.

2015-01-01

Aims We assessed levels and patterns of alcohol policy enforcement activities among U.S. local law enforcement agencies. Design/Setting/Participants We conducted a cross-sectional survey of a representative sample of 1,631 local law enforcement agencies across the 50 states. Measures/Methods We assessed 29 alcohol policy enforcement activities within each of five enforcement domains—underage alcohol possession/consumption, underage alcohol provision, underage alcohol sales, impaired driving, and overservice of alcohol—and conducted a series of latent class analyses to identify unique classes or patterns of enforcement activity for each domain. Findings We identified three to four unique enforcement activity classes for each of the enforcement domains. In four of the domains, we identified a Uniformly Low class (i.e., little or no enforcement) and a Uniformly High enforcement activity class (i.e., relatively high levels of enforcement), with one or two middle classes where some but not all activities were conducted. The underage provision domain had a Uniformly Low class but not a Uniformly High class. The Uniformly Low class was the most prevalent class in three domains: underage provision (58%), underage sales (61%), and overservice (79%). In contrast, less than a quarter of agencies were in Uniformly High classes. Conclusions We identified qualitatively distinct patterns of enforcement activity, with a large proportion of agencies in classes characterized by little or no enforcement and fewer agencies in high enforcement classes. An important next step is to determine if these patterns are associated with rates of alcohol use and alcohol-related injury and mortality. PMID:26877822

Multiplex Controller Aptitude Test and Occupational Knowledge Test: Selection Tools for Air Traffic Controllers.

DTIC Science & Technology

1981-12-15

for 6o7e (B), which became slightly more platykurtic . Thus, there appeared to be a learning effect transferred from MCAT1 to MCAT2 resulting in higher... platykurtic ) except for positive 0.27 for OKT 102E. There was a more uniform distilbution of scores for the OKT than for the MCAT tests. The test scoies

Leveraging the Cloud for Integrated Network Experimentation

DTIC Science & Technology

2014-03-01

kernel settings, or any of the low-level subcomponents. 3. Scalable Solutions: Businesses can build scalable solutions for their clients , ranging from...values. These values 13 can assume several distributions that include normal, Pareto , uniform, exponential and Poisson, among others [21]. Additionally, D...communication, the web client establishes a connection to the server before traffic begins to flow. Web servers do not initiate connections to clients in

Time allocation shifts and pollutant exposure due to traffic congestion: an analysis using the national human activity pattern survey.

PubMed

Zhang, Kai; Batterman, Stuart A

2009-10-15

Traffic congestion increases air pollutant exposures of commuters and urban populations due to the increased time spent in traffic and the increased vehicular emissions that occur in congestion, especially "stop-and-go" traffic. Increased time in traffic also decreases time in other microenvironments, a trade-off that has not been considered in previous time activity pattern (TAP) analyses conducted for exposure assessment purposes. This research investigates changes in time allocations and exposures that result from traffic congestion. Time shifts were derived using data from the National Human Activity Pattern Survey (NHAPS), which was aggregated to nine microenvironments (six indoor locations, two outdoor locations and one transport location). After imputing missing values, handling outliers, and conducting other quality checks, these data were stratified by respondent age, employment status and period (weekday/weekend). Trade-offs or time-shift coefficients between time spent in vehicles and the eight other microenvironments were then estimated using robust regression. For children and retirees, congestion primarily reduced the time spent at home; for older children and working adults, congestion shifted the time spent at home as well as time in schools, public buildings, and other indoor environments. Changes in benzene and PM(2.5) exposure were estimated for the current average travel delay in the U.S. (9 min day(-1)) and other scenarios using the estimated time shifts coefficients, concentrations in key microenvironments derived from the literature, and a probabilistic analysis. Changes in exposures depended on the duration of the congestion and the pollutant. For example, a 30 min day(-1) travel delay was determined to account for 21+/-12% of current exposure to benzene and 14+/-8% of PM(2.5) exposure. The time allocation shifts and the dynamic approach to TAPs improve estimates of exposure impacts from congestion and other recurring events.

Epidemiology of traffic crash mortality in west of Iran in a 9 year period.

PubMed

Hamzeh, Behrooz; Najafi, Farid; Karamimatin, Behzad; Ahmadijouybari, Tuoraj; Salari, Aresh; Moradinazar, Mehdi

2016-04-01

In Iran, the most common cause of injuries and the second leading cause of deaths are traffic accidents, and those problems impose a substantial financial burden on the society. This study aims to determine traffic accident mortality trends and their epidemiologic characteristics in the Kermanshah province, west of Iran. In a cross sectional study, road traffic fatality data from 2004 to 2013 were analyzed to determine the epidemiological pattern of traffic accident mortality. Trend assessment was performed to ascertain the decreasing or increasing status. Chi-square and one-way analysis of variance (ANOVA) tests, as well as Poisson regression were used to determine the significance of the data in time. Data were analyzed using Excel and statistical package of SPSS version 19. Out of 5110 people that died in traffic accidents, 4024 (78.7%) were males. The state of accidents indicated that 404 (43.8%) female pedestrians died as a result of car crashes, and 1330 (41.4%) males died because of car collisions. 1554 (31.9%) deaths happened to pedestrians and 1556 (32.1%) to vehicle drivers, and the rest belonged to vehicle passengers. Head trauma was the cause of death for as much as 3400 (69.9%) cases. Fatal crashes in which pedestrians were involved mostly occurred between the hours 13:00 to 15:00, while the time for vehicle drivers was between 16:00 to 18:00. 2882 people (59.1%) died before reaching to health care facilities. Traffic crash mortality trend for pedestrians follows a linear pattern with a gentle downward slope, but the trend shows various swings when it comes to vehicle drivers. The number of traffic crash deaths from 2004 to 2013 indicates a decreasing trend in two groups of road users: vehicle drivers and car occupants. This can be due to some interventions such as modification of traffic rules and enhancement of police control which has been implemented in recent years. Moreover, more attention should be paid to promote the optimal health care services to save the lives of the injured from traffic accidents.

SIMULATION AND VISUALIZATION OF FLOW PATTERN IN MICROARRAYS FOR LIQUID PHASE OLIGONUCLEOTIDE AND PEPTIDE SYNTHESIS

PubMed Central

O-Charoen, Sirimon; Srivannavit, Onnop; Gulari, Erdogan

2008-01-01

Microfluidic microarrays have been developed for economical and rapid parallel synthesis of oligonucleotide and peptide libraries. For a synthesis system to be reproducible and uniform, it is crucial to have a uniform reagent delivery throughout the system. Computational fluid dynamics (CFD) is used to model and simulate the microfluidic microarrays to study geometrical effects on flow patterns. By proper design geometry, flow uniformity could be obtained in every microreactor in the microarrays. PMID:17480053

Achieving pattern uniformity in plasmonic lithography by spatial frequency selection

NASA Astrophysics Data System (ADS)

Liang, Gaofeng; Chen, Xi; Zhao, Qing; Guo, L. Jay

2018-01-01

The effects of the surface roughness of thin films and defects on photomasks are investigated in two representative plasmonic lithography systems: thin silver film-based superlens and multilayer-based hyperbolic metamaterial (HMM). Superlens can replicate arbitrary patterns because of its broad evanescent wave passband, which also makes it inherently vulnerable to the roughness of the thin film and imperfections of the mask. On the other hand, the HMM system has spatial frequency filtering characteristics and its pattern formation is based on interference, producing uniform and stable periodic patterns. In this work, we show that the HMM system is more immune to such imperfections due to its function of spatial frequency selection. The analyses are further verified by an interference lithography system incorporating the photoresist layer as an optical waveguide to improve the aspect ratio of the pattern. It is concluded that a system capable of spatial frequency selection is a powerful method to produce deep-subwavelength periodic patterns with high degree of uniformity and fidelity.

Evaluation of daily time spent in transportation and traffic-influenced microenvironments by urban Canadians.

PubMed

Matz, Carlyn J; Stieb, David M; Egyed, Marika; Brion, Orly; Johnson, Markey

2018-01-01

Exposure to traffic and traffic-related air pollution is associated with a wide array of health effects. Time spent in a vehicle, in active transportation, along roadsides, and in close proximity to traffic can substantially contribute to daily exposure to air pollutants. For this study, we evaluated daily time spent in transportation and traffic-influenced microenvironments by urban Canadians using the Canadian Human Activity Pattern Survey (CHAPS) 2 results. Approximately 4-7% of daily time was spent in on- or near-road locations, mainly associated with being in a vehicle and smaller contributions from active transportation. Indoor microenvironments can be impacted by traffic emissions, especially when located near major roadways. Over 60% of the target population reported living within one block of a roadway with moderate to heavy traffic, which was variable with income level and city, and confirmed based on elevated NO 2 exposure estimated using land use regression. Furthermore, over 55% of the target population ≤ 18 years reported attending a school or daycare in close proximity to moderate to heavy traffic, and little variation was observed based on income or city. The results underline the importance of traffic emissions as a major source of exposure in Canadian urban centers, given the time spent in traffic-influenced microenvironments.

A Dynamic Programming Approach for Base Station Sleeping in Cellular Networks

NASA Astrophysics Data System (ADS)

Gong, Jie; Zhou, Sheng; Niu, Zhisheng

The energy consumption of the information and communication technology (ICT) industry, which has become a serious problem, is mostly due to the network infrastructure rather than the mobile terminals. In this paper, we focus on reducing the energy consumption of base stations (BSs) by adjusting their working modes (active or sleep). Specifically, the objective is to minimize the energy consumption while satisfying quality of service (QoS, e.g., blocking probability) requirement and, at the same time, avoiding frequent mode switching to reduce signaling and delay overhead. The problem is modeled as a dynamic programming (DP) problem, which is NP-hard in general. Based on cooperation among neighboring BSs, a low-complexity algorithm is proposed to reduce the size of state space as well as that of action space. Simulations demonstrate that, with the proposed algorithm, the active BS pattern well meets the time variation and the non-uniform spatial distribution of system traffic. Moreover, the tradeoff between the energy saving from BS sleeping and the cost of switching is well balanced by the proposed scheme.

To and From Campus: Changing Student Transportation Patterns.

ERIC Educational Resources Information Center

Fink, Ira Stephen

A thorough study of changing student transportation patterns is justified on the grounds that (1) campuses are major traffic generators; (2) there is increased concern over the need to develop transportation systems that pose less ecological threat to the urban environment; (3) transportation patterns of students, faculty, and staff are changing…

Unsupervised Ensemble Anomaly Detection Using Time-Periodic Packet Sampling

NASA Astrophysics Data System (ADS)

Uchida, Masato; Nawata, Shuichi; Gu, Yu; Tsuru, Masato; Oie, Yuji

We propose an anomaly detection method for finding patterns in network traffic that do not conform to legitimate (i.e., normal) behavior. The proposed method trains a baseline model describing the normal behavior of network traffic without using manually labeled traffic data. The trained baseline model is used as the basis for comparison with the audit network traffic. This anomaly detection works in an unsupervised manner through the use of time-periodic packet sampling, which is used in a manner that differs from its intended purpose — the lossy nature of packet sampling is used to extract normal packets from the unlabeled original traffic data. Evaluation using actual traffic traces showed that the proposed method has false positive and false negative rates in the detection of anomalies regarding TCP SYN packets comparable to those of a conventional method that uses manually labeled traffic data to train the baseline model. Performance variation due to the probabilistic nature of sampled traffic data is mitigated by using ensemble anomaly detection that collectively exploits multiple baseline models in parallel. Alarm sensitivity is adjusted for the intended use by using maximum- and minimum-based anomaly detection that effectively take advantage of the performance variations among the multiple baseline models. Testing using actual traffic traces showed that the proposed anomaly detection method performs as well as one using manually labeled traffic data and better than one using randomly sampled (unlabeled) traffic data.

Design and fabrication of semi-transparent screen based on micro-patterns for direct-view type head-up display in automobiles

NASA Astrophysics Data System (ADS)

Lee, Jae-Yong; Kim, Hyo-Jun; Kim, Young-Joo

2016-02-01

A semi-transparent screen with hemisphere micro-patterns was proposed and designed to enhance the brightness uniformity of the display image toward the driver for a direct-view type head-up display. The hemisphere micro-patterns were designed to consider the inclined angle of the windshield for efficient reflection and scattering toward to the driver. The density and radius of the hemisphere micro-patterns were adjusted as a function of position on the screen based on the geometrical calculation and analyzed by the commercial optical simulation tool based on a ray-tracing method. The designed hemisphere micro-patterns was fabricated by the thermal reflow method and evaluated to confirm the uniform illumination. From the results, the semi-transparent screen with variable micro-patterns shows the 91.9 % of brightness uniformity with the enhanced luminance compare to a screen without micro-patterns. A luminance of fabricated screen also shows good agreement with the simulation result to reflect the clear and bright driving information to the driver.

Chip-scale pattern modification method for equalizing residual layer thickness in nanoimprint lithography

NASA Astrophysics Data System (ADS)

Youn, Sung-Won; Suzuki, Kenta; Hiroshima, Hiroshi

2018-06-01

A software program for modifying a mold design to obtain a uniform residual layer thickness (RLT) distribution has been developed and its validity was verified by UV-nanoimprint lithography (UV-NIL) simulation. First, the effects of granularity (G) on both residual layer uniformity and filling characteristics were characterized. For a constant complementary pattern depth and a granularity that was sufficiently larger than the minimum pattern width, filling time decreased with the decrease in granularity. For a pattern design with a wide density range and an irregular distribution, the choice of a small granularity was not always a good strategy since the etching depth required for a complementary pattern occasionally exceptionally increased with the decrease in granularity. On basis of the results obtained, the automated method was applied to a chip-scale pattern modification. Simulation results showed a marked improvement in residual layer thickness uniformity for a capacity-equalized (CE) mold. For the given conditions, the standard deviation of RLT decreased in the range from 1/3 to 1/5 in accordance with pattern designs.

Differential Effects of Roads and Traffic on Space Use and Movements of Native Forest-Dependent and Introduced Edge-Tolerant Species

PubMed Central

Chen, Hsiang Ling; Koprowski, John L.

2016-01-01

Anthropogenic infrastructure such as roads and non-native species are major causes of species endangerment. Understanding animal behavioral responses to roads and traffic provides insight into causes and mechanisms of effects of linear development on wildlife and aids effective mitigation and conservation. We investigated effects of roads and traffic on space use and movements of two forest-dwelling species: endemic, forest-dependent Mount Graham red squirrels (Tamiasciurus hudsonicus grahamensis) and introduced, edge-tolerant Abert’s squirrels (Sciurus aberti). To assess the effects of roads on space use and movement patterns, we compared the probability that a squirrel home range included roads and random lines in forests, and assessed effects of traffic intensity on rate of road crossing and movement patterns. Red squirrels avoided areas adjacent to roads and rarely crossed roads. In contrast, Abert’s squirrels were more likely to include roads in their home ranges compared to random lines in forests. Both red squirrels and Abert’s squirrels increased speed when crossing roads, compared to before and after road crossings. Increased hourly traffic volume reduced the rate of road crossings by both species. Behavioral responses of red squirrels to roads and traffic resemble responses to elevated predation risk, including reduced speed near roads and increased tortuosity of movement paths with increased traffic volume. In contrast, Abert’s squirrels appeared little affected by roads and traffic with tortuosity of movement paths reduced as distance to roads decreased. We found that species with similar body size category (<1 kg) but different habitat preference and foraging strategy responded to roads differently and demonstrated that behavior and ecology are important when considering effects of roads on wildlife. Our results indicate that roads restricted movements and space use of a native forest-dependent species while creating habitat preferred by an introduced, edge-tolerant species. PMID:26821366

Differential Effects of Roads and Traffic on Space Use and Movements of Native Forest-Dependent and Introduced Edge-Tolerant Species.

PubMed

Chen, Hsiang Ling; Koprowski, John L

2016-01-01

Anthropogenic infrastructure such as roads and non-native species are major causes of species endangerment. Understanding animal behavioral responses to roads and traffic provides insight into causes and mechanisms of effects of linear development on wildlife and aids effective mitigation and conservation. We investigated effects of roads and traffic on space use and movements of two forest-dwelling species: endemic, forest-dependent Mount Graham red squirrels (Tamiasciurus hudsonicus grahamensis) and introduced, edge-tolerant Abert's squirrels (Sciurus aberti). To assess the effects of roads on space use and movement patterns, we compared the probability that a squirrel home range included roads and random lines in forests, and assessed effects of traffic intensity on rate of road crossing and movement patterns. Red squirrels avoided areas adjacent to roads and rarely crossed roads. In contrast, Abert's squirrels were more likely to include roads in their home ranges compared to random lines in forests. Both red squirrels and Abert's squirrels increased speed when crossing roads, compared to before and after road crossings. Increased hourly traffic volume reduced the rate of road crossings by both species. Behavioral responses of red squirrels to roads and traffic resemble responses to elevated predation risk, including reduced speed near roads and increased tortuosity of movement paths with increased traffic volume. In contrast, Abert's squirrels appeared little affected by roads and traffic with tortuosity of movement paths reduced as distance to roads decreased. We found that species with similar body size category (<1 kg) but different habitat preference and foraging strategy responded to roads differently and demonstrated that behavior and ecology are important when considering effects of roads on wildlife. Our results indicate that roads restricted movements and space use of a native forest-dependent species while creating habitat preferred by an introduced, edge-tolerant species.

Increasingly minimal bias routing

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

Bataineh, Abdulla; Court, Thomas; Roweth, Duncan

2017-02-21

A system and algorithm configured to generate diversity at the traffic source so that packets are uniformly distributed over all of the available paths, but to increase the likelihood of taking a minimal path with each hop the packet takes. This is achieved by configuring routing biases so as to prefer non-minimal paths at the injection point, but increasingly prefer minimal paths as the packet proceeds, referred to herein as Increasing Minimal Bias (IMB).

Development of a Portable Test Kit for Field-Screening Paints

DTIC Science & Technology

1986-01-01

Use) rods. TT-P-002119 Paint, Latex Base, High Traffic Areas, Flat and Eggshell Finish Discussion (Low Lustre, For Interior Use) The applications...testing uniformity in different clean. Eggshell or flat surfaces have more pigment than laboratories. Although the methods are designed to vehicle on...samples (Table 12) were selected from the useful for determining the gloss of eggshell , semigloss, series to represent the range of gloss (glossy

Time-activity relationships to VOC personal exposure factors

NASA Astrophysics Data System (ADS)

Edwards, Rufus D.; Schweizer, Christian; Llacqua, Vito; Lai, Hak Kan; Jantunen, Matti; Bayer-Oglesby, Lucy; Künzli, Nino

Social and demographic factors have been found to play a significant role in differences between time-activity patterns of population subgroups. Since time-activity patterns largely influence personal exposure to compounds as individuals move across microenvironments, exposure subgroups within the population may be defined by factors that influence daily activity patterns. Socio-demographic and environmental factors that define time-activity subgroups also define quantifiable differences in VOC personal exposures to different sources and individual compounds in the Expolis study. Significant differences in exposures to traffic-related compounds ethylbenzene, m- and p-xylene and o-xylene were observed in relation to gender, number of children and living alone. Categorization of exposures further indicated time exposed to traffic at work and time in a car as important determinants. Increased exposures to decane, nonane and undecane were observed for males, housewives and self-employed. Categorization of exposures indicated exposure subgroups related to workshop use and living downtown. Higher exposures to 3-carene and α-pinene commonly found in household cleaning products and fragrances were associated with more children, while exposures to traffic compounds ethylbenzene, m- and p-xylene and o-xylene were reduced with more children. Considerable unexplained variation remained in categorization of exposures associated with home product use and fragrances, due to individual behavior and product choice. More targeted data collection methods in VOC exposure studies for these sources should be used. Living alone was associated with decreased exposures to 2-methyl-1-propanol and 1-butanol, and traffic-related compounds. Identification of these subgroups may help to reduce the large amount of unexplained variation in VOC exposure studies. Further they may help in assessing impacts of urban planning that result in changes in behavior of individuals, resulting in shifts in the patterns of exposure experienced by the population.

Optimization of a multi-well array SERS chip

NASA Astrophysics Data System (ADS)

Abell, J. L.; Driskell, J. D.; Dluhy, R. A.; Tripp, R. A.; Zhao, Y.-P.

2009-05-01

SERS-active substrates are fabricated by oblique angle deposition and patterned by a polymer-molding technique to provide a uniform array for high throughput biosensing and multiplexing. Using a conventional SERS-active molecule, 1,2-Bis(4-pyridyl)ethylene (BPE), we show that this device provides a uniform Raman signal enhancement from well to well. The patterning technique employed in this study demonstrates a flexibility allowing for patterning control and customization, and performance optimization of the substrate. Avian influenza is analyzed to demonstrate the ability of this multi-well patterned SERS substrate for biosensing.

Traffic engineering and regenerator placement in GMPLS networks with restoration

NASA Astrophysics Data System (ADS)

Yetginer, Emre; Karasan, Ezhan

2002-07-01

In this paper we study regenerator placement and traffic engineering of restorable paths in Generalized Multipro-tocol Label Switching (GMPLS) networks. Regenerators are necessary in optical networks due to transmission impairments. We study a network architecture where there are regenerators at selected nodes and we propose two heuristic algorithms for the regenerator placement problem. Performances of these algorithms in terms of required number of regenerators and computational complexity are evaluated. In this network architecture with sparse regeneration, offline computation of working and restoration paths is studied with bandwidth reservation and path rerouting as the restoration scheme. We study two approaches for selecting working and restoration paths from a set of candidate paths and formulate each method as an Integer Linear Programming (ILP) prob-lem. Traffic uncertainty model is developed in order to compare these methods based on their robustness with respect to changing traffic patterns. Traffic engineering methods are compared based on number of additional demands due to traffic uncertainty that can be carried. Regenerator placement algorithms are also evaluated from a traffic engineering point of view.

Spatial Copula Model for Imputing Traffic Flow Data from Remote Microwave Sensors

PubMed Central

Ma, Xiaolei; Du, Bowen; Yu, Bin

2017-01-01

Issues of missing data have become increasingly serious with the rapid increase in usage of traffic sensors. Analyses of the Beijing ring expressway have showed that up to 50% of microwave sensors pose missing values. The imputation of missing traffic data must be urgently solved although a precise solution that cannot be easily achieved due to the significant number of missing portions. In this study, copula-based models are proposed for the spatial interpolation of traffic flow from remote traffic microwave sensors. Most existing interpolation methods only rely on covariance functions to depict spatial correlation and are unsuitable for coping with anomalies due to Gaussian consumption. Copula theory overcomes this issue and provides a connection between the correlation function and the marginal distribution function of traffic flow. To validate copula-based models, a comparison with three kriging methods is conducted. Results indicate that copula-based models outperform kriging methods, especially on roads with irregular traffic patterns. Copula-based models demonstrate significant potential to impute missing data in large-scale transportation networks. PMID:28934164

Demonstration of UV LED versatility when paired with molded UV transmitting glass optics to produce unique irradiance patterns

NASA Astrophysics Data System (ADS)

Jasenak, Brian

2017-02-01

Ultraviolet light-emitting diode (UV LED) adoption is accelerating; they are being used in new applications such as UV curing, germicidal irradiation, nondestructive testing, and forensic analysis. In many of these applications, it is critically important to produce a uniform light distribution and consistent surface irradiance. Flat panes of fused quartz, silica, or glass are commonly used to cover and protect UV LED arrays. However, they don't offer the advantages of an optical lens design. An investigation was conducted to determine the effect of a secondary glass optic on the uniformity of the light distribution and irradiance. Glass optics capable of transmitting UV-A, UV-B, and UV-C wavelengths can improve light distribution, uniformity, and intensity. In this work, two simulation studies were created to illustrate distinct irradiance patterns desirable for potential real world applications. The first study investigates the use of a multi-UV LED array and optic to create a uniform irradiance pattern on the flat two dimensional (2D) target surface. The uniformity was improved by designing both the LED array and molded optic to produce a homogenous pattern. The second study investigated the use of an LED light source and molded optic to improve the light uniformity on the inside of a canister. The case study illustrates the requirements for careful selection of LED based on light distribution and subsequent design of optics. The optic utilizes total internal reflection to create optimized light distribution. The combination of the LED and molded optic showed significant improvement in uniformity on the inner surface of the canister. The simulations illustrate how the application of optics can significantly improve UV light distribution which can be critical in applications such as UV curing and sterilization.

Efficient traffic grooming in SONET/WDM BLSR Networks

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

Awwal, A S; Billah, A B; Wang, B

2004-04-02

In this paper, we study traffic grooming in SONET/WDM BLSR networks under the uniform all-to-all traffic model with an objective to reduce total network costs (wavelength and electronic multiplexing costs), in particular, to minimize the number of ADMs while using the optimal number of wavelengths. We derive a new tighter lower bound for the number of wavelengths when the number of nodes is a multiple of 4. We show that this lower bound is achievable. All previous ADM lower bounds except perhaps that in were derived under the assumption that the magnitude of the traffic streams (r) is one unitmore » (r = 1) with respect to the wavelength capacity granularity g. We then derive new, more general and tighter lower bounds for the number of ADMs subject to that the optimal number of wavelengths is used, and propose heuristic algorithms (circle construction algorithm and circle grooming algorithm) that try to minimize the number of ADMs while using the optimal number of wavelengths in BLSR networks. Both the bounds and algorithms are applicable to any value of r and for different wavelength granularity g. Performance evaluation shows that wherever applicable, our lower bounds are at least as good as existing bounds and are much tighter than existing ones in many cases. Our proposed heuristic grooming algorithms perform very well with traffic streams of larger magnitude. The resulting number of ADMs required is very close to the corresponding lower bounds derived in this paper.« less

Data Mining for Understanding and Impriving Decision-Making Affecting Ground Delay Programs

NASA Technical Reports Server (NTRS)

Kulkarni, Deepak; Wang, Yao Xun; Sridhar, Banavar

2013-01-01

The continuous growth in the demand for air transportation results in an imbalance between airspace capacity and traffic demand. The airspace capacity of a region depends on the ability of the system to maintain safe separation between aircraft in the region. In addition to growing demand, the airspace capacity is severely limited by convective weather. During such conditions, traffic managers at the FAA's Air Traffic Control System Command Center (ATCSCC) and dispatchers at various Airlines' Operations Center (AOC) collaborate to mitigate the demand-capacity imbalance caused by weather. The end result is the implementation of a set of Traffic Flow Management (TFM) initiatives such as ground delay programs, reroute advisories, flow metering, and ground stops. Data Mining is the automated process of analyzing large sets of data and then extracting patterns in the data. Data mining tools are capable of predicting behaviors and future trends, allowing an organization to benefit from past experience in making knowledge-driven decisions. The work reported in this paper is focused on ground delay programs. Data mining algorithms have the potential to develop associations between weather patterns and the corresponding ground delay program responses. If successful, they can be used to improve and standardize TFM decision resulting in better predictability of traffic flows on days with reliable weather forecasts. The approach here seeks to develop a set of data mining and machine learning models and apply them to historical archives of weather observations and forecasts and TFM initiatives to determine the extent to which the theory can predict and explain the observed traffic flow behaviors.

Modeling Traffic on the Web Graph

NASA Astrophysics Data System (ADS)

Meiss, Mark R.; Gonçalves, Bruno; Ramasco, José J.; Flammini, Alessandro; Menczer, Filippo

Analysis of aggregate and individual Web requests shows that PageRank is a poor predictor of traffic. We use empirical data to characterize properties of Web traffic not reproduced by Markovian models, including both aggregate statistics such as page and link traffic, and individual statistics such as entropy and session size. As no current model reconciles all of these observations, we present an agent-based model that explains them through realistic browsing behaviors: (1) revisiting bookmarked pages; (2) backtracking; and (3) seeking out novel pages of topical interest. The resulting model can reproduce the behaviors we observe in empirical data, especially heterogeneous session lengths, reconciling the narrowly focused browsing patterns of individual users with the extreme variance in aggregate traffic measurements. We can thereby identify a few salient features that are necessary and sufficient to interpret Web traffic data. Beyond the descriptive and explanatory power of our model, these results may lead to improvements in Web applications such as search and crawling.

A Learning System for Discriminating Variants of Malicious Network Traffic

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

Beaver, Justin M; Symons, Christopher T; Gillen, Rob

Modern computer network defense systems rely primarily on signature-based intrusion detection tools, which generate alerts when patterns that are pre-determined to be malicious are encountered in network data streams. Signatures are created reactively, and only after in-depth manual analysis of a network intrusion. There is little ability for signature-based detectors to identify intrusions that are new or even variants of an existing attack, and little ability to adapt the detectors to the patterns unique to a network environment. Due to these limitations, the need exists for network intrusion detection techniques that can more comprehensively address both known unknown networkbased attacksmore » and can be optimized for the target environment. This work describes a system that leverages machine learning to provide a network intrusion detection capability that analyzes behaviors in channels of communication between individual computers. Using examples of malicious and non-malicious traffic in the target environment, the system can be trained to discriminate between traffic types. The machine learning provides insight that would be difficult for a human to explicitly code as a signature because it evaluates many interdependent metrics simultaneously. With this approach, zero day detection is possible by focusing on similarity to known traffic types rather than mining for specific bit patterns or conditions. This also reduces the burden on organizations to account for all possible attack variant combinations through signatures. The approach is presented along with results from a third-party evaluation of its performance.« less

A Hidden Markov Model for Urban-Scale Traffic Estimation Using Floating Car Data.

PubMed

Wang, Xiaomeng; Peng, Ling; Chi, Tianhe; Li, Mengzhu; Yao, Xiaojing; Shao, Jing

2015-01-01

Urban-scale traffic monitoring plays a vital role in reducing traffic congestion. Owing to its low cost and wide coverage, floating car data (FCD) serves as a novel approach to collecting traffic data. However, sparse probe data represents the vast majority of the data available on arterial roads in most urban environments. In order to overcome the problem of data sparseness, this paper proposes a hidden Markov model (HMM)-based traffic estimation model, in which the traffic condition on a road segment is considered as a hidden state that can be estimated according to the conditions of road segments having similar traffic characteristics. An algorithm based on clustering and pattern mining rather than on adjacency relationships is proposed to find clusters with road segments having similar traffic characteristics. A multi-clustering strategy is adopted to achieve a trade-off between clustering accuracy and coverage. Finally, the proposed model is designed and implemented on the basis of a real-time algorithm. Results of experiments based on real FCD confirm the applicability, accuracy, and efficiency of the model. In addition, the results indicate that the model is practicable for traffic estimation on urban arterials and works well even when more than 70% of the probe data are missing.

Reasons underlying behaviour of motorcyclists disregarding traffic regulations in urban areas of Indonesia.

PubMed

Susilo, Yusak O; Joewono, Tri Basuki; Vandebona, Upali

2015-02-01

Over the last decade, motorcycle use has been rapidly increasing in Indonesia as have violations of traffic rules committed by motorcyclists. This study aims to explore the impacts of motorcyclists' attitudes, habits, preferences, and travel patterns on their behaviour in disregarding traffic regulations in three cities in Indonesia. The theory of planned behaviour and structural equation modelling are employed to explore these relationships. Consistent with results from previous studies in developed countries, an individual's beliefs and attitudes, social norms and perceived behaviour control significantly influence behaviour in disregarding traffic rules. Young adults and students are found to be more likely to frequently violate traffic regulations. However, unlike previous findings from developed countries, in Indonesia, males are less likely to disregard traffic rules than females. Overall, pushing the motorcycle through a (very) narrow gap, speeding, driving recklessly, and overtaking on the wrong side are the most frequent traffic violations that make up repetitive violation behaviour among urban motorcyclists in Indonesia. The results highlight the need to revisit Indonesian National Traffic Law traffic violation classification and penalties and separate violations that are likely to cause fatal results, thus requiring tougher law enforcement, from violations that are unlikely to have fatal consequences. Copyright © 2014 Elsevier Ltd. All rights reserved.

Dynamically Evolving Sectors for Convective Weather Impact

NASA Technical Reports Server (NTRS)

Drew, Michael C.

2010-01-01

A new strategy for altering existing sector boundaries in response to blocking convective weather is presented. This method seeks to improve the reduced capacity of sectors directly affected by weather by moving boundaries in a direction that offers the greatest capacity improvement. The boundary deformations are shared by neighboring sectors within the region in a manner that preserves their shapes and sizes as much as possible. This reduces the controller workload involved with learning new sector designs. The algorithm that produces the altered sectors is based on a force-deflection mesh model that needs only nominal traffic patterns and the shape of the blocking weather for input. It does not require weather-affected traffic patterns that would have to be predicted by simulation. When compared to an existing optimal sector design method, the sectors produced by the new algorithm are more similar to the original sector shapes, resulting in sectors that may be more suitable for operational use because the change is not as drastic. Also, preliminary results show that this method produces sectors that can equitably distribute the workload of rerouted weather-affected traffic throughout the region where inclement weather is present. This is demonstrated by sector aircraft count distributions of simulated traffic in weather-affected regions.

Pattern of Injuries from Road Traffic Accidents Presented at a Rural Teaching Institution of Karachi.

PubMed

Shamim, Muhammad

2017-08-01

The aim of the study is to study the pattern of injuries from road traffic accidents presented at the emergency department of a rural teaching institution in Karachi. This descriptive case series was conducted prospectively in the Emergency Department of Fatima Hospital and Baqai Medical University from 1 January 2012 to 21 March 2013. There were 385 patients in the series. All of the patients with recent injuries from road traffic accidents were included. Cases with injuries more than 72 h old were excluded. The majority of patients had lower limb injuries 172 (44.7%), followed by head and neck injuries 107 (27.8%), multiple injuries 62 (16.1%), upper limb injuries 22 (5.7%), abdominoperineal injuries 19 (5%), and chest injuries 3 (0.8%). Majority (229, 59.5%) of patients were given first aid treatment and discharged, while 151 (39.3%) patients were either admitted or referred to better equipped hospitals. Three patients were brought dead, and two patients left against medical advice. The lower limb injuries were the commonest road traffic accidental injuries, followed by head and neck injuries, multiple injuries, upper limb injuries, abdominoperineal injuries, and chest injuries.

Peeking Network States with Clustered Patterns

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

Kim, Jinoh; Sim, Alex

2015-10-20

Network traffic monitoring has long been a core element for effec- tive network management and security. However, it is still a chal- lenging task with a high degree of complexity for comprehensive analysis when considering multiple variables and ever-increasing traffic volumes to monitor. For example, one of the widely con- sidered approaches is to scrutinize probabilistic distributions, but it poses a scalability concern and multivariate analysis is not gen- erally supported due to the exponential increase of the complexity. In this work, we propose a novel method for network traffic moni- toring based on clustering, one of the powerful deep-learningmore » tech- niques. We show that the new approach enables us to recognize clustered results as patterns representing the network states, which can then be utilized to evaluate “similarity” of network states over time. In addition, we define a new quantitative measure for the similarity between two compared network states observed in dif- ferent time windows, as a supportive means for intuitive analysis. Finally, we demonstrate the clustering-based network monitoring with public traffic traces, and show that the proposed approach us- ing the clustering method has a great opportunity for feasible, cost- effective network monitoring.« less

Improving global CD uniformity by optimizing post-exposure bake and develop sequences

NASA Astrophysics Data System (ADS)

Osborne, Stephen P.; Mueller, Mark; Lem, Homer; Reyland, David; Baik, KiHo

2003-12-01

Improvements in the final uniformity of masks can be shrouded by error contributions from many sources. The final Global CD Uniformity (GCDU) of a mask is degraded by individual contributions of the writing tool, the Post Applied Bake (PAB), the Post Exposure Bake (PEB), the Develop sequence and the Etch step. Final global uniformity will improve by isolating and minimizing the variability of the PEB and Develop. We achieved this de-coupling of the PEB and Develop process from the whole process stream by using "dark loss" which is the loss of unexposed resist during the develop process. We confirmed a correspondence between Angstroms of dark loss and nanometer sized deviations in the chrome CD. A plate with a distinctive dark loss pattern was related to a nearly identical pattern in the chrome CD. This pattern was verified to have originated during the PEB process and displayed a [Δ(Final CD)/Δ(Dark Loss)] ratio of 6 for TOK REAP200 resist. Previous papers have reported a sensitive linkage between Angstroms of dark loss and nanometers in the final uniformity of the written plate. These initial studies reported using this method to improve the PAB of resists for greater uniformity of sensitivity and contrast. Similarly, this paper demonstrates an outstanding optimization of PEB and Develop processes.

CD uniformity control for thick resist process

NASA Astrophysics Data System (ADS)

Huang, Chi-hao; Liu, Yu-Lin; Wang, Weihung; Yang, Mars; Yang, Elvis; Yang, T. H.; Chen, K. C.

2017-03-01

In order to meet the increasing storage capacity demand and reduce bit cost of NAND flash memories, 3D stacked flash cell array has been proposed. In constructing 3D NAND flash memories, the higher bit number per area is achieved by increasing the number of stacked layers. Thus the so-called "staircase" patterning to form electrical connection between memory cells and word lines has become one of the primarily critical processes in 3D memory manufacture. To provide controllable critical dimension (CD) with good uniformity involving thick photo-resist has also been of particular concern for staircase patterning. The CD uniformity control has been widely investigated with relatively thinner resist associated with resolution limit dimension but thick resist coupling with wider dimension. This study explores CD uniformity control associated with thick photo-resist processing. Several critical parameters including exposure focus, exposure dose, baking condition, pattern size and development recipe, were found to strongly correlate with the thick photo-resist profile accordingly affecting the CD uniformity control. To minimize the within-wafer CD variation, the slightly tapered resist profile is proposed through well tailoring the exposure focus and dose together with optimal development recipe. Great improvements on DCD (ADI CD) and ECD (AEI CD) uniformity as well as line edge roughness were achieved through the optimization of photo resist profile.

Noise, air pollutants and traffic: continuous measurement and correlation at a high-traffic location in New York City.

PubMed

Ross, Zev; Kheirbek, Iyad; Clougherty, Jane E; Ito, Kazuhiko; Matte, Thomas; Markowitz, Steven; Eisl, Holger

2011-11-01

Epidemiological studies have linked both noise and air pollution to common adverse health outcomes such as increased blood pressure and myocardial infarction. In urban settings, noise and air pollution share important sources, notably traffic, and several recent studies have shown spatial correlations between noise and air pollution. The temporal association between these exposures, however, has yet to be thoroughly investigated despite the importance of time series studies in air pollution epidemiology and the potential that correlations between these exposures could at least partly confound statistical associations identified in these studies. An aethelometer, for continuous elemental carbon measurement, was co-located with a continuous noise monitor near a major urban highway in New York City for six days in August 2009. Hourly elemental carbon measurements and hourly data on overall noise levels and low, medium and high frequency noise levels were collected. Hourly average concentrations of fine particles and nitrogen oxides, wind speed and direction and car, truck and bus traffic were obtained from nearby regulatory monitors. Overall temporal patterns, as well as day-night and weekday-weekend patterns, were characterized and compared for all variables. Noise levels were correlated with car, truck, and bus traffic and with air pollutants. We observed strong day-night and weekday-weekend variation in noise and air pollutants and correlations between pollutants varied by noise frequency. Medium and high frequency noise were generally more strongly correlated with traffic and traffic-related pollutants than low frequency noise and the correlation with medium and high frequency noise was generally stronger at night. Correlations with nighttime high frequency noise were particularly high for car traffic (Spearman rho=0.84), nitric oxide (0.73) and nitrogen dioxide (0.83). Wind speed and direction mediated relationships between pollutants and noise. Noise levels are temporally correlated with traffic and combustion pollutants and correlations are modified by the time of day, noise frequency and wind. Our results underscore the potential importance of assessing temporal variation in co-exposures to noise and air pollution in studies of the health effects of these urban pollutants. Copyright © 2011 Elsevier Inc. All rights reserved.

SERENITY in Air Traffic Management

NASA Astrophysics Data System (ADS)

Felici, Massimo; Meduri, Valentino; Tedeschi, Alessandra; Riccucci, Carlo

This chapter is concerned with the validation of an implementation of the SERENITY Runtime Framework (SRF) tailored for the Air Traffic Management (ATM) domain. It reports our experience in the design and validation phases of a tool, which relies on the SRF in order to support Security and Dependability (S&D) Patterns into work practices. In particular, this chapter pinpoints the activities concerning the identification of S&D Patterns, the design of an ATM prototype and its validation. The validation activities involve qualitative as well as quantitative approaches. These activities as a whole highlight the validation process for adopting S&D Patterns within the ATM domain. Moreover, they stress how S&D Patters enhance and relate to critical features within an industry domain. The empirical results point out that S&D Patterns relate to work practices. Furthermore, they highlight design and validation activities in order to tailor systems relying on S&D Patterns to specific application domains. This strengths and supports the adoption of S&D Patterns in order to address AmI (Ambient Intelligence) requirements (e.g., awareness, proactiveness, resilience, etc.) within the ATM domain.

The Use of Compressive Sensing to Reconstruct Radiation Characteristics of Wide-Band Antennas from Sparse Measurements

DTIC Science & Technology

2015-06-01

of uniform- versus nonuniform -pattern reconstruction, of transform function used, and of minimum randomly distributed measurements needed to...the radiation-frequency pattern’s reconstruction using uniform and nonuniform randomly distributed samples even though the pattern error manifests...5 Fig. 3 The nonuniform compressive-sensing reconstruction of the radiation

Chromatic induction in space and time.

PubMed

Coia, Andrew J; Shevell, Steven K

2018-04-01

The color appearance of a light depends on variation in the complete visual field over both space and time. In the spatial domain, a chromatic stimulus within a patterned chromatic surround can appear a different hue than the same stimulus within a uniform surround. In the temporal domain, a stimulus presented as an element of a continuously changing chromaticity can appear a different color compared to the identical stimulus, presented simultaneously but viewed alone. This is the flash-lag effect for color, which has an analog in the domain of motion: a pulsed object seen alone can appear to lag behind an identical pulsed object that is an element of a motion sequence. Studies of the flash-lag effect for motion have considered whether it is mediated by a neural representation for the moving physical stimulus or, alternatively, for the perceived motion. The current study addresses this question for the flash-lag effect for color by testing whether the color flash lag depends on a representation of only the changing chromatic stimulus or, alternatively, its color percept, which can be altered by chromatic induction. baseline measurements for spatial chromatic induction determined the chromaticity of a flashed ring within a uniform surround that matched a flashed ring within a patterned surround. Baseline measurements for the color flash-lag effect determined the chromaticity of a pulsed ring presented alone (within a uniform surround) that matched a pulsed ring presented in a sequence of changing chromaticity over time (also within a uniform surround). Finally, the main experiments combined chromatic induction from a patterned surround and the flash-lag effect, in three conditions: (1) both the changing and pulsed rings were within a patterned chromatic surround; (2) the changing ring was within a patterned surround and the pulsed ring within a uniform surround; and (3) the changing ring was within a uniform surround and the pulsed ring within a patterned surround. the flash-lag measurements for a changing chromaticity were affected by perceptual changes induced by the surrounding chromatic pattern. Thus, the color shifts induced by a chromatic surround are incorporated in the neural representation mediating the flash-lag effect for color.

Analysis of user equilibrium for staggered shifts in a single-entry traffic corridor with no late arrivals

NASA Astrophysics Data System (ADS)

Li, Chuan-Yao; Huang, Hai-Jun; Tang, Tie-Qiao

2017-05-01

In this paper, we investigate the effects of staggered shifts on the user equilibrium (UE) state in a single-entry traffic corridor with no late arrivals from the analytical and numerical perspective. The LWR (Lighthill-Whitham-Richards) model and the Greenshields' velocity-density function are used to describe the dynamic properties of traffic flow. Propositions for the properties of flow patterns in UE, and the quasi-analytic solutions for three possible situations in UE are deduced. Numerical tests are carried out to testify the analytical results, where the three-dimensional evolution diagram of traffic flow illustrates that shock and rarefaction wave exist in UE and the space-time diagram indicates that UE solutions satisfy the propagation properties of traffic flow. In addition, the cost curves show that the UE solutions satisfy the UE trip-timing condition.

Comparing five front-of-pack nutrition labels' influence on consumers' perceptions and purchase intentions.

PubMed

Gorski Findling, Mary T; Werth, Paul M; Musicus, Aviva A; Bragg, Marie A; Graham, Dan J; Elbel, Brian; Roberto, Christina A

2018-01-01

In 2011, a National Academy of Medicine report recommended that packaged food in the U.S. display a uniform front-of-package nutrition label, using a system such as a 0-3 star ranking. Few studies have directly compared this to other labels to determine which best informs consumers and encourages healthier purchases. In 2013, we randomized adult participants (N=1247) in an Internet-based survey to one of six conditions: no label control; single traffic light; multiple traffic light; Facts Up Front; NuVal; or 0-3 star ranking. We compared groups on purchase intentions and accuracy of participants' interpretation of food labels. There were no differences in the nutritional quality of hypothetical shopping baskets across conditions (p=0.845). All labels improved consumers' abilities to judge the nutritional quality of foods relative to no label, but the best designs varied by outcomes. NuVal and multiple traffic light labels led to the greatest accuracy identifying the healthier of two products (p<0.001), while the multiple traffic light also led to the most accurate estimates of saturated fat, sugar, and sodium (p<0.001). The single traffic light outperformed other labels when participants compared nutrient levels between similar products (p<0.03). Single/multiple traffic light and Facts Up Front labels led to the most accurate calories per serving estimations (p<0.001). Although front-of-package labels helped participants more accurately assess products' nutrition information relative to no label, no conditions shifted adults' purchase intentions. Results did not point to a clearly superior label design, but they suggest that a 3-star label might not be best for educating consumers. Copyright © 2017 Elsevier Inc. All rights reserved.

Temporal variation of traffic on highways and the development of accurate temporal allocation factors for air pollution analyses

NASA Astrophysics Data System (ADS)

Batterman, Stuart; Cook, Richard; Justin, Thomas

2015-04-01

Traffic activity encompasses the number, mix, speed and acceleration of vehicles on roadways. The temporal pattern and variation of traffic activity reflects vehicle use, congestion and safety issues, and it represents a major influence on emissions and concentrations of traffic-related air pollutants. Accurate characterization of vehicle flows is critical in analyzing and modeling urban and local-scale pollutants, especially in near-road environments and traffic corridors. This study describes methods to improve the characterization of temporal variation of traffic activity. Annual, monthly, daily and hourly temporal allocation factors (TAFs), which describe the expected temporal variation in traffic activity, were developed using four years of hourly traffic activity data recorded at 14 continuous counting stations across the Detroit, Michigan, U.S. region. Five sites also provided vehicle classification. TAF-based models provide a simple means to apportion annual average estimates of traffic volume to hourly estimates. The analysis shows the need to separate TAFs for total and commercial vehicles, and weekdays, Saturdays, Sundays and observed holidays. Using either site-specific or urban-wide TAFs, nearly all of the variation in historical traffic activity at the street scale could be explained; unexplained variation was attributed to adverse weather, traffic accidents and construction. The methods and results presented in this paper can improve air quality dispersion modeling of mobile sources, and can be used to evaluate and model temporal variation in ambient air quality monitoring data and exposure estimates.

Temporal variation of traffic on highways and the development of accurate temporal allocation factors for air pollution analyses

PubMed Central

Batterman, Stuart; Cook, Richard; Justin, Thomas

2015-01-01

Traffic activity encompasses the number, mix, speed and acceleration of vehicles on roadways. The temporal pattern and variation of traffic activity reflects vehicle use, congestion and safety issues, and it represents a major influence on emissions and concentrations of traffic-related air pollutants. Accurate characterization of vehicle flows is critical in analyzing and modeling urban and local-scale pollutants, especially in near-road environments and traffic corridors. This study describes methods to improve the characterization of temporal variation of traffic activity. Annual, monthly, daily and hourly temporal allocation factors (TAFs), which describe the expected temporal variation in traffic activity, were developed using four years of hourly traffic activity data recorded at 14 continuous counting stations across the Detroit, Michigan, U.S. region. Five sites also provided vehicle classification. TAF-based models provide a simple means to apportion annual average estimates of traffic volume to hourly estimates. The analysis shows the need to separate TAFs for total and commercial vehicles, and weekdays, Saturdays, Sundays and observed holidays. Using either site-specific or urban-wide TAFs, nearly all of the variation in historical traffic activity at the street scale could be explained; unexplained variation was attributed to adverse weather, traffic accidents and construction. The methods and results presented in this paper can improve air quality dispersion modeling of mobile sources, and can be used to evaluate and model temporal variation in ambient air quality monitoring data and exposure estimates. PMID:25844042

Assessment and prediction of road accident injuries trend using time-series models in Kurdistan.

PubMed

Parvareh, Maryam; Karimi, Asrin; Rezaei, Satar; Woldemichael, Abraha; Nili, Sairan; Nouri, Bijan; Nasab, Nader Esmail

2018-01-01

Road traffic accidents are commonly encountered incidents that can cause high-intensity injuries to the victims and have direct impacts on the members of the society. Iran has one of the highest incident rates of road traffic accidents. The objective of this study was to model the patterns of road traffic accidents leading to injury in Kurdistan province, Iran. A time-series analysis was conducted to characterize and predict the frequency of road traffic accidents that lead to injury in Kurdistan province. The injuries were categorized into three separate groups which were related to the car occupants, motorcyclists and pedestrian road traffic accident injuries. The Box-Jenkins time-series analysis was used to model the injury observations applying autoregressive integrated moving average (ARIMA) and seasonal autoregressive integrated moving average (SARIMA) from March 2009 to February 2015 and to predict the accidents up to 24 months later (February 2017). The analysis was carried out using R-3.4.2 statistical software package. A total of 5199 pedestrians, 9015 motorcyclists, and 28,906 car occupants' accidents were observed. The mean (SD) number of car occupant, motorcyclist and pedestrian accident injuries observed were 401.01 (SD 32.78), 123.70 (SD 30.18) and 71.19 (SD 17.92) per year, respectively. The best models for the pattern of car occupant, motorcyclist, and pedestrian injuries were the ARIMA (1, 0, 0), SARIMA (1, 0, 2) (1, 0, 0) 12 , and SARIMA (1, 1, 1) (0, 0, 1) 12 , respectively. The motorcyclist and pedestrian injuries showed a seasonal pattern and the peak was during summer (August). The minimum frequency for the motorcyclist and pedestrian injuries were observed during the late autumn and early winter (December and January). Our findings revealed that the observed motorcyclist and pedestrian injuries had a seasonal pattern that was explained by air temperature changes overtime. These findings call the need for close monitoring of the accidents during the high-risk periods in order to control and decrease the rate of the injuries.

Benzene patterns in different urban environments and a prediction model for benzene rates based on NOx values

NASA Astrophysics Data System (ADS)

Paz, Shlomit; Goldstein, Pavel; Kordova-Biezuner, Levana; Adler, Lea

2017-04-01

Exposure to benzene has been associated with multiple severe impacts on health. This notwithstanding, at most monitoring stations, benzene is not monitored on a regular basis. The aims of the study were to compare benzene rates in different urban environments (region with heavy traffic and industrial region), to analyse the relationship between benzene and meteorological parameters in a Mediterranean climate type, to estimate the linkages between benzene and NOx and to suggest a prediction model for benzene rates based on NOx levels in order contribute to a better estimation of benzene. Data were used from two different monitoring stations, located on the eastern Mediterranean coast: 1) a traffic monitoring station in Tel Aviv, Israel (TLV) located in an urban region with heavy traffic; 2) a general air quality monitoring station in Haifa Bay (HIB), located in Israel's main industrial region. At each station, hourly, daily, monthly, seasonal, and annual data of benzene, NOx, mean temperature, relative humidity, inversion level, and temperature gradient were analysed over three years: 2008, 2009, and 2010. A prediction model for benzene rates based on NOx levels (which are monitored regularly) was developed to contribute to a better estimation of benzene. The severity of benzene pollution was found to be considerably higher at the traffic monitoring station (TLV) than at the general air quality station (HIB), despite the location of the latter in an industrial area. Hourly, daily, monthly, seasonal, and annual patterns have been shown to coincide with anthropogenic activities (traffic), the day of the week, and atmospheric conditions. A strong correlation between NOx and benzene allowed the development of a prediction model for benzene rates, based on NOx, the day of the week, and the month. The model succeeded in predicting the benzene values throughout the year (except for September). The severity of benzene pollution was found to be considerably higher at the traffic station (TLV) than at the general air quality station (HIB), despite being located in an industrial area. Hourly, daily, seasonal, and annual patterns of benzene rates have been shown to coincide with anthropogenic activities (traffic), day of the week, and atmospheric conditions. A prediction model for benzene rates was developed, based on NOx, the day of the week, and the month. The model suggested in this study might be useful for identifying potential risk of benzene in other urban environments.

Performance Analysis of the SensorNet's Southeastern Transportation Corridor Pilot Viewer at the Dorchester West Bound Interstate Weigh Station

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

Colon Mendoza, R.A.; Lagos, L.E.; Hill, D.E.

2008-07-01

Since the 9-11 attacks, the United States has increased its focus on developing technologies designed to warn us in the event of another attack and to prevent these attacks from happening in the first place. The SensorNet research group at Oak Ridge National Laboratory's (ORNL) Computer Science and Engineering Division is participating in this effort by developing systems to give critical real-time information to federal, state, and local emergency response decision makers. SensorNet has approached this goal by putting together a system with several sensors and programs called the Southeastern Transportation Corridor Pilot project (SETCP). The SETCP utilizes interstate weighmore » stations not only to weigh the passing trucks but also to check for gamma and neutron radiation inside the truck without the aid of a human in close proximity. The system also collects additional data that help identify the truck (the truck's length, weight, license plate number, and photographs of the truck). The objective of this research work was to characterize and analyze the data collected from the South Carolina weigh station on I-26W and compare it with previous data analysis on the performance of the Tennessee weigh station on I-40E. The purpose was to find patterns in the trucks with radioactive alarms and, regional truck traffic, as well as to find patterns of inconsistency in the system (illogical length measurements of the truck, inaccurate readings and character recognition of the license plate). During a three-month period, radioactive alarms and traffic patterns were identified and characterized by grouping all of the data and making graphs and charts in Microsoft Excel to show the flow of traffic, the type of truck traffic, the number of alarms and other information. Inconsistence patterns were found by analyzing the data, looking for missing or illogical information, and determining how often it happens. The improvements of these inconsistencies were also analyzed after repairs were made to the system. Given the small number of radiation alarms detected, there were no clear patterns found. Further research has to be done in this area; also, the analysis period needs to be extended from three months to a year. For traffic flow patterns, it was found that the truck traffic was heaviest on Monday, Tuesday, and Wednesday. The inconsistencies found and fixed in the system were the illogical length measurements and the inaccurate reading and character recognition of the license plate. During the summer of 2007, a Florida International University (FIU) student supported this research work under the direct supervision of Mr. David Hill at ORNL's Computer Science and Engineering Division. The 10-week student internship was supported by the DOE/FIU Science and Technology Workforce Initiative, an innovative program developed by the US Department of Energy's Environmental Management (DOE-EM) and FIU's Applied Research Center (FIU-ARC) (authors)« less

A New Method to Measure Temperature and Burner Pattern Factor Sensing for Active Engine Control

NASA Technical Reports Server (NTRS)

Ng, Daniel

1999-01-01

The determination of the temperatures of extended surfaces which exhibit non-uniform temperature variation is very important for a number of applications including the "Burner Pattern Factor" (BPF) of turbine engines. Exploratory work has shown that use of BPF to control engine functions can result in many benefits, among them reduction in engine weight, reduction in operating cost, increase in engine life, while attaining maximum engine efficiency. Advanced engines are expected to operate at very high temperature to achieve high efficiency. Brief exposure of engine components to higher than design temperatures due to non-uniformity in engine burner pattern can reduce engine life. The engine BPF is a measure of engine temperature uniformity. Attainment of maximum temperature uniformity and high temperatures is key to maximum efficiency and long life. A new approach to determine through the measurement of just one radiation spectrum by a multiwavelength pyrometer is possible. This paper discusses a new temperature sensing approach and its application to determine the BPF.

Characterization and Processing of Non-Uniformities in Back-Illuminated CCDs

NASA Astrophysics Data System (ADS)

Lemm, Alia D.; Della-Rose, Devin J.; Maddocks, Sally

2018-01-01

In astronomical photometry, Charged Coupled Device (CCD) detectors are used to achieve high precision photometry and must be properly calibrated to correct for noise and pixel non-uniformities. Uncalibrated images may contain bias offset, dark current, bias structure and uneven illumination. In addition, standard data reduction is often not sufficient to “normalize” imagery to single-digit millimagnitude (mmag) precision. We are investigating an apparent non-uniformity, or interference pattern, in a back-illuminated sensor, the Alta U-47, attached to a DFM Engineering 41-cm Ritchey-Chrétien f/8 telescope. Based on the amplitude of this effect, we estimate that instrument magnitude peak-to-valley deviations of 50 mmag or more may result. Our initial testing strongly suggests that reflected skylight from high pressure sodium city lights may be the cause of this interference pattern. Our research goals are twofold: to fully characterize this non-uniformity and to determine the best method to remove this interference pattern from our reduced CCD images.

Precision Positional Data of General Aviation Air Traffic in Terminal Air Space

NASA Technical Reports Server (NTRS)

Melson, W. E., Jr.; Parker, L. C.; Northam, A. M.; Singh, R. P.

1978-01-01

Three dimensional radar tracks of general aviation air traffic at three uncontrolled airports are considered. Contained are data which describe the position-time histories, other derived parameters, and reference data for the approximately 1200 tracks. All information was correlated such that the date, time, flight number, and runway number match the pattern type, aircraft type, wind, visibility, and cloud conditions.

Population-Level Exposure to Particulate Air Pollution during Active Travel: Planning for Low-Exposure, Health-Promoting Cities.

PubMed

Hankey, Steve; Lindsey, Greg; Marshall, Julian D

2017-04-01

Providing infrastructure and land uses to encourage active travel (i.e., bicycling and walking) are promising strategies for designing health-promoting cities. Population-level exposure to air pollution during active travel is understudied. Our goals were a ) to investigate population-level patterns in exposure during active travel, based on spatial estimates of bicycle traffic, pedestrian traffic, and particulate concentrations; and b ) to assess how those exposure patterns are associated with the built environment. We employed facility-demand models (active travel) and land use regression models (particulate concentrations) to estimate block-level ( n = 13,604) exposure during rush-hour (1600-1800 hours) in Minneapolis, Minnesota. We used the model-derived estimates to identify land use patterns and characteristics of the street network that are health promoting. We also assessed how exposure is correlated with indicators of health disparities (e.g., household income, proportion of nonwhite residents). Our work uses population-level rates of active travel (i.e., traffic flows) rather than the probability of walking or biking (i.e., "walkability" or "bikeability") to assess exposure. Active travel often occurs on high-traffic streets or near activity centers where particulate concentrations are highest (i.e., 20-42% of active travel occurs on blocks with high population-level exposure). Only 2-3% of blocks (3-8% of total active travel) are "sweet spots" (i.e., high active travel, low particulate concentrations); sweet spots are located a ) near but slightly removed from the city-center or b ) on off-street trails. We identified 1,721 blocks (~ 20% of local roads) where shifting active travel from high-traffic roads to adjacent low-traffic roads would reduce exposure by ~ 15%. Active travel is correlated with population density, land use mix, open space, and retail area; particulate concentrations were mostly unchanged with land use. Public health officials and urban planners may use our findings to promote healthy transportation choices. When designing health-promoting cities, benefits (physical activity) as well as hazards (air pollution) should be evaluated.

Modulated grayscale UV pattern for uniform photopolymerization based on a digital micromirror device system

NASA Astrophysics Data System (ADS)

Yoon, Jinsik; Kim, Kibeom; Park, Wook

2017-07-01

We present an essential method for generating microparticles uniformly in a single ultraviolet (UV) light exposure area for optofluidic maskless lithography. In the optofluidic maskless lithography process, the productivity of monodisperse microparticles depends on the size of the UV exposure area. An effective fabrication area is determined by the size of the UV intensity profile map, satisfying the required uniformity of UV intensity. To increase the productivity of monodisperse microparticles in optofluidic maskless lithography, we expanded the effective UV exposure area by modulating the intensity of the desired UV light pattern based on the premeasured UV intensity profile map. We verified the improvement of the uniformity of the microparticles generated by the proposed modulation technique, providing histogram analyses of the conjugated fluorescent intensities and the sizes of the microparticles. Additionally, we demonstrated the generation of DNA uniformly encapsulated in microparticles.

A system for learning statistical motion patterns.

PubMed

Hu, Weiming; Xiao, Xuejuan; Fu, Zhouyu; Xie, Dan; Tan, Tieniu; Maybank, Steve

2006-09-01

Analysis of motion patterns is an effective approach for anomaly detection and behavior prediction. Current approaches for the analysis of motion patterns depend on known scenes, where objects move in predefined ways. It is highly desirable to automatically construct object motion patterns which reflect the knowledge of the scene. In this paper, we present a system for automatically learning motion patterns for anomaly detection and behavior prediction based on a proposed algorithm for robustly tracking multiple objects. In the tracking algorithm, foreground pixels are clustered using a fast accurate fuzzy K-means algorithm. Growing and prediction of the cluster centroids of foreground pixels ensure that each cluster centroid is associated with a moving object in the scene. In the algorithm for learning motion patterns, trajectories are clustered hierarchically using spatial and temporal information and then each motion pattern is represented with a chain of Gaussian distributions. Based on the learned statistical motion patterns, statistical methods are used to detect anomalies and predict behaviors. Our system is tested using image sequences acquired, respectively, from a crowded real traffic scene and a model traffic scene. Experimental results show the robustness of the tracking algorithm, the efficiency of the algorithm for learning motion patterns, and the encouraging performance of algorithms for anomaly detection and behavior prediction.

Research on Near Field Pattern Effects.

DTIC Science & Technology

1981-01-01

block numbr) High frequency solutions Prolate spheroid mounted antennas Uniform Geometrical Theory of Diffraction Airborne antenna pattern predicti...Geometrical Theory of Diffraction solutions which were developed previously were DD 1473 EDITION OF I NOV 66 IS OBSOLETE UCASFE SECURITY CLASSIFICATION...be used later to simulate the fuselage of a general aircraft. The general uniform Geometrical Theory of Diffraction (GTD) solutions [1i which are

Optimizing congestion and emissions via tradable credit charge and reward scheme without initial credit allocations

NASA Astrophysics Data System (ADS)

Zhu, Wenlong; Ma, Shoufeng; Tian, Junfang

2017-01-01

This paper investigates the revenue-neutral tradable credit charge and reward scheme without initial credit allocations that can reassign network traffic flow patterns to optimize congestion and emissions. First, we prove the existence of the proposed schemes and further decentralize the minimum emission flow pattern to user equilibrium. Moreover, we design the solving method of the proposed credit scheme for minimum emission problem. Second, we investigate the revenue-neutral tradable credit charge and reward scheme without initial credit allocations for bi-objectives to obtain the Pareto system optimum flow patterns of congestion and emissions; and present the corresponding solutions are located in the polyhedron constituted by some inequalities and equalities system. Last, numerical example based on a simple traffic network is adopted to obtain the proposed credit schemes and verify they are revenue-neutral.

Vessel traffic patterns in the Port of Kaohsiung and the management implications for preventing the introduction of non-indigenous aquatic species.

PubMed

Liu, Ta-Kang; Tsai, Tzung-Kuen

2011-03-01

Data on shipping traffic in one of the busiest seaports in the world, the Port of Kaohsiung, were analyzed to evaluate the implications for ballast water management. Results show that 67% of the arriving vessels were registered to a flag of convenience, which typically have a lower degree of environmental records. The top five donor countries historically suffer from harmful algal bloom problems. The short journey and busy trading between these countries and Taiwan lead to a higher risk of inoculation. In addition, only 1.4% of all vessels visited more than once every year during the 9-year span, indicating that the port authority encounters many new vessels each year. These findings could influence the design and application of ballast water management strategies as well as highlight the challenges in their implementation. We suggest that an analysis of vessel traffic patterns should be coupled with other useful vessel information to make risk assessment successful. Copyright © 2010. Published by Elsevier Ltd.

NOx profile around a signalized intersection of busy roadway

NASA Astrophysics Data System (ADS)

Kim, Kyung Hwan; Lee, Seung-Bok; Woo, Sung Ho; Bae, Gwi-Nam

2014-11-01

The NOx pollution profile around a signalized intersection of a busy roadway was investigated to understand the effect of traffic control on urban air pollution. Traffic flow patterns were classified into three categories of quasi-cruising, a combination of deceleration and acceleration, and a combination of deceleration, idling, and acceleration. The spatial distribution of air pollution levels around an intersection could be represented as a quasi-normal distribution, whose peak height was aggravated by increased emissions due to transient driving patterns. The peak concentration of NOx around the signalized intersection for the deceleration, idling, and acceleration category was five times higher than that for the quasi-cruising category. Severe levels of NOx pollution tailed off approximately 400 m from the center of the intersection. Approximately 200-1000 ppb of additional NOx was observed when traffic was decelerating, idling, and accelerating within the intersection zone, resulting in high exposure levels for pedestrians around the intersection. We propose a fluctuating horizontal distribution of motor vehicle-induced air pollutants as a function of time.

Discrete Mathematical Approaches to Graph-Based Traffic Analysis

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

Joslyn, Cliff A.; Cowley, Wendy E.; Hogan, Emilie A.

2014-04-01

Modern cyber defense and anlaytics requires general, formal models of cyber systems. Multi-scale network models are prime candidates for such formalisms, using discrete mathematical methods based in hierarchically-structured directed multigraphs which also include rich sets of labels. An exemplar of an application of such an approach is traffic analysis, that is, observing and analyzing connections between clients, servers, hosts, and actors within IP networks, over time, to identify characteristic or suspicious patterns. Towards that end, NetFlow (or more generically, IPFLOW) data are available from routers and servers which summarize coherent groups of IP packets flowing through the network. In thismore » paper, we consider traffic analysis of Netflow using both basic graph statistics and two new mathematical measures involving labeled degree distributions and time interval overlap measures. We do all of this over the VAST test data set of 96M synthetic Netflow graph edges, against which we can identify characteristic patterns of simulated ground-truth network attacks.« less

Evaluating the air quality impacts of the 2008 Beijing Olympic Games: On-road emission factors and black carbon profiles

NASA Astrophysics Data System (ADS)

Wang, Xing; Westerdahl, Dane; Chen, Lung Chi; Wu, Ye; Hao, Jiming; Pan, Xiaochuan; Guo, Xinbiao; Zhang, K. Max

The aggressive traffic interventions and emission control measures implemented to improve air quality during the 2008 Beijing Olympic Games created a valuable case study to evaluate the effectiveness of these measures on mitigating air pollution and protecting public health. In this paper, we report the results from our field campaign in summer 2008 on the on-road emission factors of carbon monoxide, black carbon (BC) and ultrafine particles (UFP) as well as the ambient BC concentrations. The fleet average emission factors for light-duty gasoline vehicles (LDGV) showed considerable reduction in the Olympic year (2008) compared to the pre-Olympic year (2007). Our measurement of Black Carbon (BC), a primary pollutant, at different elevations at the ambient site suggests consistent decrease in BC concentrations as the height increased near the ground level, which indicates that the nearby ground level sources, probably dominated by traffic, contributed to a large portion of BC concentrations in the lower atmospheric layer in Beijing during summertime. These observations indicate that people living in near ground levels experience higher exposures than those living in higher floors in Beijing. The BC diurnal patterns on days when traffic control were in place during the Olympic Games were compared to those on non-traffic-control days in both 2007 and in 2008. These patterns strongly suggest that diesel trucks are a major source of summertime BC in Beijing. The median BC concentration on Olympic days was 3.7 μg m -3, which was dramatically lower than the value on non-traffic-control days, indicating the effectiveness of traffic control regulations in BC reduction in Beijing.

Characteristics of trace metals in traffic-derived particles in Hsuehshan Tunnel, Taiwan: size distribution, fingerprinting metal ratio, and emission factor

NASA Astrophysics Data System (ADS)

Lin, Y.-C.; Tsai, C.-J.; Wu, Y.-C.; Zhang, R.; Chi, K.-H.; Huang, Y.-T.; Lin, S.-H.; Hsu, S.-C.

2014-05-01

Traffic emissions are a significant source of airborne particulate matter (PM) in ambient environments. These emissions contain high abundance of toxic metals and thus pose adverse effects on human health. Size-fractionated aerosol samples were collected from May to September 2013 by using micro-orifice uniform deposited impactor (MOUDI). Sample collection was conducted simultaneously at the inlet and outlet sites of Hsuehshan Tunnel in northern Taiwan, which is the second longest freeway tunnel (12.9 km) in Asia. Such endeavor aims to characterize the chemical constituents, size distributions, and fingerprinting ratios, as well as the emission factors of particulate metals emitted by vehicle fleets. A total of 36 metals in size-resolved aerosols were determined through inductively coupled plasma mass spectrometry. Three major groups, namely, tailpipe emissions (Zn, Pb, and V), wear debris (Cu, Cd, Fe, Ga, Mn, Mo, Sb, and Sn), and resuspended dust (Ca, Mg, K, and Rb), of airborne PM metals were categorized on the basis of the results of enrichment factor, correlation matrix, and principal component analysis. Size distributions of wear-originated metals resembled the pattern of crustal elements, which were predominated by super-micron particulates (PM1-10). By contrast, tailpipe exhaust elements such as Zn, Pb, and V were distributed mainly in submicron particles. By employing Cu as a tracer of wear abrasion, several inter-metal ratios, including Fe/Cu (14), Ba/Cu (1.05), Sb/Cu (0.16), Sn/Cu (0.10), and Ga/Cu (0.03), served as fingerprints for wear debris. Emission factor of PM10 mass was estimated to be 7.7 mg vkm-1. The metal emissions were mostly predominated in super-micron particles (PM1-10). Finally, factors that possibly affect particulate metal emissions inside Hsuehshan Tunnel are discussed.

Patterns of drinking and driving offenses among nightclub patrons in Brazil.

PubMed

Wagner, Gabriela A; Sanchez, Zila M

2017-05-01

Brazil has a strict drinking and driving law known as the Brazilian "Dry Law". The aim of the present study was to investigate characteristics associated with the breaking of the Brazilian traffic law, on drinking and driving, at nightclub exit among a representative sample of nightclub patrons in the city of São Paulo, Brazil. Portal survey realized with a two-stage cluster sampling survey design to collect data from 2422 patrons at the entrance and 1822 patrons at the exit of 31 nightclubs in the city of São Paulo, Brazil. Patrons' breath alcohol concentrations (BrACs) at the entrance and exit of the nightclubs were categorized according to the law as either a "traffic offense" or a "traffic offense and crime". Weighted multinomial logistic regression was used to analyze factors associated with different patterns of drinking and driving offenses. Of the subjects, 16.5% (n=369) were identified as driving patrons at the entrance and exit of the nightclubs. At entry, 80.1% of the patrons had a zero BrAC, 14.9% had a BrAC meeting the traffic offense criteria and 5.0% had a BrAC meeting the traffic offense and crime criteria. Women were less likely to have BrACs meeting the traffic offense criteria. At nightclub exit, 63.4% of patrons had maintained a zero BrAC, 24.7% had a BrAC that had increased and now met the traffic offense and crime criteria, and 11.9% had a decreased or stable BrAC. An increased BrAC was more frequently identified in patrons who were men, were single, and had used illicit drugs inside the nightclub. Despite the existence of a strict law regarding drinking and driving, a significant proportion of nightclub patrons in the city of São Paulo had violated this law, suggesting a perception of impunity and need for law enforcement. Copyright © 2017 Elsevier B.V. All rights reserved.

The Impact of Large Urban Structural Elements on Traffic Flow   a Case Study of Danwei and Xiaoqu in Shanghai

NASA Astrophysics Data System (ADS)

Lyu, H.; Ding, L.; Fan, H.; Meng, L.

2017-09-01

Danwei (working unit) and Xiaoqu (residential community) are two typical and unique structural urban elements in China. The interior roads of Danwei and Xiaoqu are usually not accessible for the public. Recently, there is a call for opening these interior roads to the public to improve road network structure and optimize traffic flow. In this paper we investigate the impact of Danwei and Xiaoqu on their neighbouring traffic quantitatively. By taking into consideration of origins and destinations (ODs) distributions and route selection behaviours (e.g., shortest paths), we propose an extended betweenness centrality to investigate the traffic flow in two scenarios 1) the interior roads of Danwei and Xiaoqu are excluded from urban road network, 2) the interior roads are integrated into road network. A Danwei and a Xiaoqu in Shanghai are used as the study area. The preliminary results show the feasibility of our extended betweenness centrality in investigating the traffic flow patterns and reveal the quantitative changes of the traffic flow after opening interior roads.

Remote Video Monitor of Vehicles in Cooperative Information Platform

NASA Astrophysics Data System (ADS)

Qin, Guofeng; Wang, Xiaoguo; Wang, Li; Li, Yang; Li, Qiyan

Detection of vehicles plays an important role in the area of the modern intelligent traffic management. And the pattern recognition is a hot issue in the area of computer vision. An auto- recognition system in cooperative information platform is studied. In the cooperative platform, 3G wireless network, including GPS, GPRS (CDMA), Internet (Intranet), remote video monitor and M-DMB networks are integrated. The remote video information can be taken from the terminals and sent to the cooperative platform, then detected by the auto-recognition system. The images are pretreated and segmented, including feature extraction, template matching and pattern recognition. The system identifies different models and gets vehicular traffic statistics. Finally, the implementation of the system is introduced.

Optimized Sensor Network and Multi-Agent Decision Support for Smart Traffic Light Management.

PubMed

Cruz-Piris, Luis; Rivera, Diego; Fernandez, Susel; Marsa-Maestre, Ivan

2018-02-02

One of the biggest challenges in modern societies is to solve vehicular traffic problems. Sensor networks in traffic environments have contributed to improving the decision-making process of Intelligent Transportation Systems. However, one of the limiting factors for the effectiveness of these systems is in the deployment of sensors to provide accurate information about the traffic. Our proposal is using the centrality measurement of a graph as a base to locate the best locations for sensor installation in a traffic network. After integrating these sensors in a simulation scenario, we define a Multi-Agent Systems composed of three types of agents: traffic light management agents, traffic jam detection agents, and agents that control the traffic lights at an intersection. The ultimate goal of these Multi-Agent Systems is to improve the trip duration for vehicles in the network. To validate our solution, we have developed the needed elements for modelling the sensors and agents in the simulation environment. We have carried out experiments using the Simulation of Urban MObility (SUMO) traffic simulator and the Travel and Activity PAtterns Simulation (TAPAS) Cologne traffic scenario. The obtained results show that our proposal allows to reduce the sensor network while still obtaining relevant information to have a global view of the environment. Finally, regarding the Multi-Agent Systems, we have carried out experiments that show that our proposal is able to improve other existing solutions such as conventional traffic light management systems (static or dynamic) in terms of reduction of vehicle trip duration and reduction of the message exchange overhead in the sensor network.

Optimized Sensor Network and Multi-Agent Decision Support for Smart Traffic Light Management

PubMed Central

2018-01-01

One of the biggest challenges in modern societies is to solve vehicular traffic problems. Sensor networks in traffic environments have contributed to improving the decision-making process of Intelligent Transportation Systems. However, one of the limiting factors for the effectiveness of these systems is in the deployment of sensors to provide accurate information about the traffic. Our proposal is using the centrality measurement of a graph as a base to locate the best locations for sensor installation in a traffic network. After integrating these sensors in a simulation scenario, we define a Multi-Agent Systems composed of three types of agents: traffic light management agents, traffic jam detection agents, and agents that control the traffic lights at an intersection. The ultimate goal of these Multi-Agent Systems is to improve the trip duration for vehicles in the network. To validate our solution, we have developed the needed elements for modelling the sensors and agents in the simulation environment. We have carried out experiments using the Simulation of Urban MObility (SUMO) traffic simulator and the Travel and Activity PAtterns Simulation (TAPAS) Cologne traffic scenario. The obtained results show that our proposal allows to reduce the sensor network while still obtaining relevant information to have a global view of the environment. Finally, regarding the Multi-Agent Systems, we have carried out experiments that show that our proposal is able to improve other existing solutions such as conventional traffic light management systems (static or dynamic) in terms of reduction of vehicle trip duration and reduction of the message exchange overhead in the sensor network. PMID:29393884

Learn on the Fly: Quiescent Routing in Wireless Sensor Networks

DTIC Science & Technology

2005-02-01

quality solely based on data traf- fic without employing beacons. Using a realistic sensor network traffic trace and an 802.11b testbed of 195 Stargates ...testbed of 195 Stargates [1] with 802.11b radios. For instance, we investigate the validity of geographic uniformity which is assumed in literature [19...Figure 1), we deploy 29 Stargates in a straight line, with a 45-meter separation between any two consecutive Stargates . The Stargates run Linux with

Effect of display update interval, update type, and background on perception of aircraft separation on a cockpit display on traffic information

NASA Technical Reports Server (NTRS)

Jago, S.; Baty, D.; Oconnor, S.; Palmer, E.

1981-01-01

The concept of a cockpit display of traffic information (CDTI) includes the integration of air traffic, navigation, and other pertinent information in a single electronic display in the cockpit. Concise display symbology was developed for use in later full-mission simulator evaluations of the CDTI concept. Experimental variables used included the update interval motion of the aircraft, the update type, (that is, whether the two aircraft were updated at the same update interval or not), the background (grid pattern or no background), and encounter type (straight or curved). Only the type of encounter affected performance.

Daylight saving time can decrease the frequency of wildlife–vehicle collisions

PubMed Central

Ellis, William A.; FitzGibbon, Sean I.; Barth, Benjamin J.; Niehaus, Amanda C.; David, Gwendolyn K.; Taylor, Brendan D.; Matsushige, Helena; Melzer, Alistair; Bercovitch, Fred B.; Carrick, Frank; Jones, Darryl N.; Dexter, Cathryn; Gillett, Amber; Predavec, Martin; Lunney, Dan

2016-01-01

Daylight saving time (DST) could reduce collisions with wildlife by changing the timing of commuter traffic relative to the behaviour of nocturnal animals. To test this idea, we tracked wild koalas (Phascolarctos cinereus) in southeast Queensland, where koalas have declined by 80% in the last 20 years, and compared their movements with traffic patterns along roads where they are often killed. Using a simple model, we found that DST could decrease collisions with koalas by 8% on weekdays and 11% at weekends, simply by shifting the timing of traffic relative to darkness. Wildlife conservation and road safety should become part of the debate on DST. PMID:27881767

Assessing risk of navigational hazard from sea-level-related datum in the South West of Java Sea, Indonesia

NASA Astrophysics Data System (ADS)

Poerbandono

2017-07-01

This paper assesses the presence of navigational hazards due to underestimation of charted depths originated from an establishment of a sea-level-related reference plane, i.e. datum. The study domain is situated in one of Indonesia's densest marine traffic, SW Java Sea, Indonesia. The assessment is based on the comparison of the authorized Chart Datum (CD), being uniformly located at 0.6 m below Mean Sea Level (MSL), and a spatially varying Lowest Astronomical Tide (LAT) generated for the purpose of this research. Hazards are considered here as the deviation of LAT from CD and quantified as the ratio of LAT -CD deviation with respect to the allowable Total Vertical Uncertainty (TVU), i.e. the international standard for accuracy of depth information on nautical charts. Underestimation of charted depth is expected for the case that LAT falls below CD. Such a risk magnifies with decreasing depths, as well as the increasing volume of traffic and draught of the vessel. It is found that most of the domain is in the interior of risk-free zone from using uniform CD. As much as 0.08 and 0.19 parts of the area are in zones where the uncertainty of CD contributes respectively to 50% and 30% of Total Vertical Uncertainty. These are zones where the hazard of navigation is expected to increase due to underestimated lowest tidal level.

Cluster pattern analysis of energy deposition sites for the brachytherapy sources 103Pd, 125I, 192Ir, 137Cs, and 60Co.

PubMed

Villegas, Fernanda; Tilly, Nina; Bäckström, Gloria; Ahnesjö, Anders

2014-09-21

Analysing the pattern of energy depositions may help elucidate differences in the severity of radiation-induced DNA strand breakage for different radiation qualities. It is often claimed that energy deposition (ED) sites from photon radiation form a uniform random pattern, but there is indication of differences in RBE values among different photon sources used in brachytherapy. The aim of this work is to analyse the spatial patterns of EDs from 103Pd, 125I, 192Ir, 137Cs sources commonly used in brachytherapy and a 60Co source as a reference radiation. The results suggest that there is both a non-uniform and a uniform random component to the frequency distribution of distances to the nearest neighbour ED. The closest neighbouring EDs show high spatial correlation for all investigated radiation qualities, whilst the uniform random component dominates for neighbours with longer distances for the three higher mean photon energy sources (192Ir, 137Cs, and 60Co). The two lower energy photon emitters (103Pd and 125I) present a very small uniform random component. The ratio of frequencies of clusters with respect to 60Co differs up to 15% for the lower energy sources and less than 2% for the higher energy sources when the maximum distance between each pair of EDs is 2 nm. At distances relevant to DNA damage, cluster patterns can be differentiated between the lower and higher energy sources. This may be part of the explanation to the reported difference in RBE values with initial DSB yields as an endpoint for these brachytherapy sources.

Cluster pattern analysis of energy deposition sites for the brachytherapy sources 103Pd, 125I, 192Ir, 137Cs, and 60Co

NASA Astrophysics Data System (ADS)

Villegas, Fernanda; Tilly, Nina; Bäckström, Gloria; Ahnesjö, Anders

2014-09-01

Analysing the pattern of energy depositions may help elucidate differences in the severity of radiation-induced DNA strand breakage for different radiation qualities. It is often claimed that energy deposition (ED) sites from photon radiation form a uniform random pattern, but there is indication of differences in RBE values among different photon sources used in brachytherapy. The aim of this work is to analyse the spatial patterns of EDs from 103Pd, 125I, 192Ir, 137Cs sources commonly used in brachytherapy and a 60Co source as a reference radiation. The results suggest that there is both a non-uniform and a uniform random component to the frequency distribution of distances to the nearest neighbour ED. The closest neighbouring EDs show high spatial correlation for all investigated radiation qualities, whilst the uniform random component dominates for neighbours with longer distances for the three higher mean photon energy sources (192Ir, 137Cs, and 60Co). The two lower energy photon emitters (103Pd and 125I) present a very small uniform random component. The ratio of frequencies of clusters with respect to 60Co differs up to 15% for the lower energy sources and less than 2% for the higher energy sources when the maximum distance between each pair of EDs is 2 nm. At distances relevant to DNA damage, cluster patterns can be differentiated between the lower and higher energy sources. This may be part of the explanation to the reported difference in RBE values with initial DSB yields as an endpoint for these brachytherapy sources.

Desynchronization boost by non-uniform coordinated reset stimulation in ensembles of pulse-coupled neurons

PubMed Central

Lücken, Leonhard; Yanchuk, Serhiy; Popovych, Oleksandr V.; Tass, Peter A.

2013-01-01

Several brain diseases are characterized by abnormal neuronal synchronization. Desynchronization of abnormal neural synchrony is theoretically compelling because of the complex dynamical mechanisms involved. We here present a novel type of coordinated reset (CR) stimulation. CR means to deliver phase resetting stimuli at different neuronal sub-populations sequentially, i.e., at times equidistantly distributed in a stimulation cycle. This uniform timing pattern seems to be intuitive and actually applies to the neural network models used for the study of CR so far. CR resets the population to an unstable cluster state from where it passes through a desynchronized transient, eventually resynchronizing if left unperturbed. In contrast, we show that the optimal stimulation times are non-uniform. Using the model of weakly pulse-coupled neurons with phase response curves, we provide an approach that enables to determine optimal stimulation timing patterns that substantially maximize the desynchronized transient time following the application of CR stimulation. This approach includes an optimization search for clusters in a low-dimensional pulse coupled map. As a consequence, model-specific non-uniformly spaced cluster states cause considerably longer desynchronization transients. Intriguingly, such a desynchronization boost with non-uniform CR stimulation can already be achieved by only slight modifications of the uniform CR timing pattern. Our results suggest that the non-uniformness of the stimulation times can be a medically valuable parameter in the calibration procedure for CR stimulation, where the latter has successfully been used in clinical and pre-clinical studies for the treatment of Parkinson's disease and tinnitus. PMID:23750134

Nonlinear relative-proportion-based route adjustment process for day-to-day traffic dynamics: modeling, equilibrium and stability analysis

NASA Astrophysics Data System (ADS)

Zhu, Wenlong; Ma, Shoufeng; Tian, Junfang; Li, Geng

2016-11-01

Travelers' route adjustment behaviors in a congested road traffic network are acknowledged as a dynamic game process between them. Existing Proportional-Switch Adjustment Process (PSAP) models have been extensively investigated to characterize travelers' route choice behaviors; PSAP has concise structure and intuitive behavior rule. Unfortunately most of which have some limitations, i.e., the flow over adjustment problem for the discrete PSAP model, the absolute cost differences route adjustment problem, etc. This paper proposes a relative-Proportion-based Route Adjustment Process (rePRAP) maintains the advantages of PSAP and overcomes these limitations. The rePRAP describes the situation that travelers on higher cost route switch to those with lower cost at the rate that is unilaterally depended on the relative cost differences between higher cost route and its alternatives. It is verified to be consistent with the principle of the rational behavior adjustment process. The equivalence among user equilibrium, stationary path flow pattern and stationary link flow pattern is established, which can be applied to judge whether a given network traffic flow has reached UE or not by detecting the stationary or non-stationary state of link flow pattern. The stability theorem is proved by the Lyapunov function approach. A simple example is tested to demonstrate the effectiveness of the rePRAP model.

How the propagation of heat-flux modulations triggers E × B flow pattern formation.

PubMed

Kosuga, Y; Diamond, P H; Gürcan, O D

2013-03-08

We propose a novel mechanism to describe E×B flow pattern formation based upon the dynamics of propagation of heat-flux modulations. The E × B flows of interest are staircases, which are quasiregular patterns of strong, localized shear layers and profile corrugations interspersed between regions of avalanching. An analogy of staircase formation to jam formation in traffic flow is used to develop an extended model of heat avalanche dynamics. The extension includes a flux response time, during which the instantaneous heat flux relaxes to the mean heat flux, determined by symmetry constraints. The response time introduced here is the counterpart of the drivers' response time in traffic, during which drivers adjust their speed to match the background traffic flow. The finite response time causes the growth of mesoscale temperature perturbations, which evolve to form profile corrugations. The length scale associated with the maximum growth rate scales as Δ(2) ~ (v(thi)/λT(i))ρ(i)sqrt[χ(neo)τ], where λT(i) is a typical heat pulse speed, χ(neo) is the neoclassical thermal diffusivity, and τ is the response time of the heat flux. The connection between the scale length Δ(2) and the staircase interstep scale is discussed.

Pattern of maxillofacial fractures in severe multiple trauma patients: a 7-year prospective study.

PubMed

Alves, La-Salete; Aragão, Irene; Sousa, Maria-José Carneiro; Gomes, Ernestina

2014-01-01

The incidence of facial trauma is high. This study has the primary objective of documenting and cataloging maxillofacial fractures in polytrauma patients. From a total of 1229 multiple trauma cases treated at the Emergency Room of the Santo Antonio Hospital - Oporto Hospital Center, Portugal, between August 2001 and December 2007, 251 patients had facial wounds and 209 had maxillofacial fractures. Aged ranged form 13 to 86 years. The applied selective method was based on the presence of facial wound with Abbreviated Injury Scale ≥1. Men had a higher incidence of maxillofacial fractures among multiple trauma patients (86.6%) and road traffic accidents were the primary cause of injuries (69.38%). Nasoorbitoethmoid complex was the most affected region (67.46%) followed by the maxilla (57.42%). The pattern and presentation of maxillofacial fractures had been studied in many parts of the world with varying results. Severe multiple trauma patients had different patterns of maxillofacial injuries. The number of maxillofacial trauma is on the rise worldwide as well as the incidence of associated sequelae. Maxillofacial fractures on multiple trauma patients were more frequent among males and in road traffic crashes. Knowing such data is elementary. The society should have a key role in the awareness of individuals and in prevention of road traffic accidents.

An evaluation of the 10:30 centerline marking pattern.

DOT National Transportation Integrated Search

1977-01-01

In response to Value Engineering Proposal #M-26, a study of the feasibility of adopting a 10 ft. mark 30 ft. gap centerline pattern for use on 2- and 4-lane rural roads was conducted. The study included a literature review, field studies of traffic s...

Boundary-induced pattern formation from uniform temporal oscillation

NASA Astrophysics Data System (ADS)

Kohsokabe, Takahiro; Kaneko, Kunihiko

2018-04-01

Pattern dynamics triggered by fixing a boundary is investigated. By considering a reaction-diffusion equation that has a unique spatially uniform and limit cycle attractor under a periodic or Neumann boundary condition, and then by choosing a fixed boundary condition, we found three novel phases depending on the ratio of diffusion constants of activator to inhibitor: transformation of temporally periodic oscillation into a spatially periodic fixed pattern, travelling wave emitted from the boundary, and aperiodic spatiotemporal dynamics. The transformation into a fixed, periodic pattern is analyzed by crossing of local nullclines at each spatial point, shifted by diffusion terms, as is analyzed by using recursive equations, to obtain the spatial pattern as an attractor. The generality of the boundary-induced pattern formation as well as its relevance to biological morphogenesis is discussed.

An approach to online network monitoring using clustered patterns

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

Kim, Jinoh; Sim, Alex; Suh, Sang C.

Network traffic monitoring is a core element in network operations and management for various purposes such as anomaly detection, change detection, and fault/failure detection. In this study, we introduce a new approach to online monitoring using a pattern-based representation of the network traffic. Unlike the past online techniques limited to a single variable to summarize (e.g., sketch), the focus of this study is on capturing the network state from the multivariate attributes under consideration. To this end, we employ clustering with its benefit of the aggregation of multidimensional variables. The clustered result represents the state of the network with regardmore » to the monitored variables, which can also be compared with the previously observed patterns visually and quantitatively. Finally, we demonstrate the proposed method with two popular use cases, one for estimating state changes and the other for identifying anomalous states, to confirm its feasibility.« less

Where Am I? Location Archetype Keyword Extraction from Urban Mobility Patterns

PubMed Central

Kostakos, Vassilis; Juntunen, Tomi; Goncalves, Jorge; Hosio, Simo; Ojala, Timo

2013-01-01

Can online behaviour be used as a proxy for studying urban mobility? The increasing availability of digital mobility traces has provided new insights into collective human behaviour. Mobility datasets have been shown to be an accurate proxy for daily behaviour and social patterns, and behavioural data from Twitter has been used to predict real world phenomena such as cinema ticket sale volumes, stock prices, and disease outbreaks. In this paper we correlate city-scale urban traffic patterns with online search trends to uncover keywords describing the pedestrian traffic location. By analysing a 3-year mobility dataset we show that our approach, called Location Archetype Keyword Extraction (LAKE), is capable of uncovering semantically relevant keywords for describing a location. Our findings demonstrate an overarching relationship between online and offline collective behaviour, and allow for advancing analysis of community-level behaviour by using online search keywords as a practical behaviour proxy. PMID:23704964

Where am I? Location archetype keyword extraction from urban mobility patterns.

PubMed

Kostakos, Vassilis; Juntunen, Tomi; Goncalves, Jorge; Hosio, Simo; Ojala, Timo

2013-01-01

Can online behaviour be used as a proxy for studying urban mobility? The increasing availability of digital mobility traces has provided new insights into collective human behaviour. Mobility datasets have been shown to be an accurate proxy for daily behaviour and social patterns, and behavioural data from Twitter has been used to predict real world phenomena such as cinema ticket sale volumes, stock prices, and disease outbreaks. In this paper we correlate city-scale urban traffic patterns with online search trends to uncover keywords describing the pedestrian traffic location. By analysing a 3-year mobility dataset we show that our approach, called Location Archetype Keyword Extraction (LAKE), is capable of uncovering semantically relevant keywords for describing a location. Our findings demonstrate an overarching relationship between online and offline collective behaviour, and allow for advancing analysis of community-level behaviour by using online search keywords as a practical behaviour proxy.

An approach to online network monitoring using clustered patterns

DOE PAGES

Kim, Jinoh; Sim, Alex; Suh, Sang C.; ...

2017-03-13

Network traffic monitoring is a core element in network operations and management for various purposes such as anomaly detection, change detection, and fault/failure detection. In this study, we introduce a new approach to online monitoring using a pattern-based representation of the network traffic. Unlike the past online techniques limited to a single variable to summarize (e.g., sketch), the focus of this study is on capturing the network state from the multivariate attributes under consideration. To this end, we employ clustering with its benefit of the aggregation of multidimensional variables. The clustered result represents the state of the network with regardmore » to the monitored variables, which can also be compared with the previously observed patterns visually and quantitatively. Finally, we demonstrate the proposed method with two popular use cases, one for estimating state changes and the other for identifying anomalous states, to confirm its feasibility.« less

Airspace Complexity and its Application in Air Traffic Management

NASA Technical Reports Server (NTRS)

Sridhar, Banavar; Chatterji, Gano; Sheth, Kapil; Edwards, Thomas (Technical Monitor)

1998-01-01

The United States Air Traffic Management (ATM) system provides services to enable safe, orderly and efficient aircraft operations within the airspace over the continental United States and over large portions of the Pacific and Atlantic Oceans, and the Gulf of Mexico. It consists of two components, Air Traffic Control (ATC) and Traffic Flow Management (TFM). The ATC function ensures that the aircraft within the airspace are separated at all times while the TFM function organizes the aircraft into a flow pattern to ensure their safe and efficient movement. In order to accomplish the ATC and TFM functions, the airspace over United States is organized into 22 Air Route Traffic Control Centers (ARTCCs). The Center airspace is stratified into low-altitude, high-altitude and super-high altitude groups of Sectors. Each vertical layer is further partitioned into several horizontal Sectors. A typical ARTCC airspace is partitioned into 20 to 80 Sectors. These Sectors are the basic control units within the ATM system.

Phase transitions in traffic flow on multilane roads.

PubMed

Kerner, Boris S; Klenov, Sergey L

2009-11-01

Based on empirical and numerical analyses of vehicular traffic, the physics of spatiotemporal phase transitions in traffic flow on multilane roads is revealed. The complex dynamics of moving jams observed in single vehicle data measured by video cameras on American highways is explained by the nucleation-interruption effect in synchronized flow, i.e., the spontaneous nucleation of a narrow moving jam with the subsequent jam dissolution. We find that (i) lane changing, vehicle merging from on-ramps, and vehicle leaving to off-ramps result in different traffic phases-free flow, synchronized flow, and wide moving jams-occurring and coexisting in different road lanes as well as in diverse phase transitions between the traffic phases; (ii) in synchronized flow, the phase transitions are responsible for a non-regular moving jam dynamics that explains measured single vehicle data: moving jams emerge and dissolve randomly at various road locations in different lanes; (iii) the phase transitions result also in diverse expanded general congested patterns occurring at closely located bottlenecks.

An epidemiological study on pattern of thoraco-abdominal injuries sustained in fatal road traffic accidents of Bangalore: Autopsy-based study.

PubMed

Reddy, N Bayapa; Hanumantha; Madithati, Pallavi; Reddy, N Nagarjuna; Reddy, C Sainarasimha

2014-04-01

The statistical profile reflects a global estimate of 5.1 million deaths in 2000, which was due to injuries that accounted for 10% of deaths due to all causes. Out of this, a quarter of injury-related deaths occurred in the South-East Asian region. Road Traffic Accident (RTA) is one among the top 5 causes of morbidity and mortality in South-East Asian countries. Most common cause of blunt abdominal trauma in India is road traffic accident followed by pedestrian accidents, abdominal blows, and fall from heights. To analyze the epidemiology and pattern of fatal thoraco-abdominal injuries in road traffic accidents. An autopsy-based cross-sectional study conducted. A purposive sampling technique was applied to select the study sample of 100 post-mortems of road traffic accident between November 2008 and May 2010 subjected to medico-legal autopsy at the department of Forensic Medicine, KIMS Hospital Bangalore. The majority of the victims were aged 21 to 40 years, 50 (50.0%), most of the victims were male 92 (92.0%); and male/female ratio was 11.5:1. Commonest offending agents in heavy motor vehicles were 54 (54.0%). Bony cage sustained injuries were observed in 71; out of this, fractures of ribs were observed in 45 (63.3%) victims, clavicle in 14 (19.7%), sternum was 6 (8.4%), and vertebrae 6 (8.4%) of fatal road traffic accidents. Internal thoracic injuries were observed in 26 cases. Among internal thoracic injuries, lungs were the most commonly involved organ 24 (92.3%) followed by the heart 2 (7.6%). Lung sustained more lacerations 19 (79.1%) than contusions 5 (20.8%). Internal abdominal injuries were observed in 49 cases. In road traffic accidents, the most commonly injured abdominal organs were solid organs such as liver 16 (32.6%) followed by spleen 9 (18.3%). Majority of the times in road traffic accidents, young and productive males were injured or lost their life. This study may help the planners to take safety measures, to implement strict traffic rules, to risk stratification in the susceptible population to educate the people, and the study of nature of offending agent in RTA can help the authorities to plan better availability of health care on roads.

Toward microscale flow control using non-uniform electro-osmotic flow

NASA Astrophysics Data System (ADS)

Paratore, Federico; Boyko, Evgeniy; Gat, Amir D.; Kaigala, Govind V.; Bercovici, Moran

2018-02-01

We present a novel method that allows establishing desired flow patterns in a Hele-Shaw cell, solely by controlling the surface chemistry, without the use of physical walls. Using weak electrolytes, we locally pattern the chamber's ceiling and/or floor, thus defining a spatial distribution of surface charge. This translates to a non-uniform electric double layer which when subjected to an external electric field applied along the chamber, gives rise to non-uniform electroosmotic flow (EOF). We present the theory that allows prediction and design of such flows fields, as well as experimental demonstrations opening the door to configurable microfluidic devices.

Hyperthermia apparatus

DOEpatents

Larsen, Lawrence E.

2000-01-01

A hyperthermia apparatus, suitable for transurethral application, has an energy radiating element comprising a leaky-wave antenna. The leaky wave antenna radiation pattern is characterized by a surface wave which propagates along an aperture formed by openings (small in comparison to a wavelength) in the outer conductor of a transmission line. Appropriate design of the leaky wave antenna produces a uniform, broadside pattern of temperature elevation that uniformly heats all or part of the periurethral tissues.

Generation of Olympic logo with freeform lens array

NASA Astrophysics Data System (ADS)

Liu, Chengkun; Huang, Qilu; Qiu, Yishen; Chen, Weijuan; Liao, Tingdi

2017-10-01

In this paper, the Olympic rings pattern is generated by using freeform lens array and illumination light source array. Based on nonimaging optics, the freeform lens array is designed for point light source, which can generate the focused pattern of annular light spot. In order to obtain the Olympic logo pattern of five rings, the array with five freeform lenses is used. By adjusting the emission angle of each light source, the annular spot is obtained at different positions of the target plane and the Olympic rings logo is formed. We used the shading plate on the surface of the freeform lens to reduce the local light intensity so that the light spot overall irradiance distribution is more uniform. We designed a freeform lens with aperture of 26.2mm, focal length of 2000mm and the diameter of a single annual spot is 400mm. We modeled freeform lens and simulated by optical software TracePro. The ray tracing results show that the Olympic rings with uniform illumination can be obtained on the target plane with the optical efficiency up to 85.7%. At the same time, this paper also studies the effects of the target plane defocusing on the spot pattern. Simulations show that when the distance of the receiving surface to the focal plane varies within 300mm, a reasonable uniform and small distorted light spot pattern can be obtained. Compared with the traditional projection method, our method of design has the advantages of high optical efficiency, low cost and the pattern is clear and uniform.

Effects of canyon geometry on the distribution of traffic-related air pollution in a large urban area: Implications of a multi-canyon air pollution dispersion model

NASA Astrophysics Data System (ADS)

Fu, Xiangwen; Liu, Junfeng; Ban-Weiss, George A.; Zhang, Jiachen; Huang, Xin; Ouyang, Bin; Popoola, Olalekan; Tao, Shu

2017-09-01

Street canyons are ubiquitous in urban areas. Traffic-related air pollutants in street canyons can adversely affect human health. In this study, an urban-scale traffic pollution dispersion model is developed considering street distribution, canyon geometry, background meteorology, traffic assignment, traffic emissions and air pollutant dispersion. In the model, vehicle exhausts generated from traffic flows first disperse inside street canyons along the micro-scale wind field generated by computational fluid dynamics (CFD) model. Then, pollutants leave the street canyon and further disperse over the urban area. On the basis of this model, the effects of canyon geometry on the distribution of NOx and CO from traffic emissions were studied over the center of Beijing. We found that an increase in building height leads to heavier pollution inside canyons and lower pollution outside canyons at pedestrian level, resulting in higher domain-averaged concentrations over the area. In addition, canyons with highly even or highly uneven building heights on each side of the street tend to lower the urban-scale air pollution concentrations at pedestrian level. Further, increasing street widths tends to lead to lower pollutant concentrations by reducing emissions and enhancing ventilation simultaneously. Our results indicate that canyon geometry strongly influences human exposure to traffic pollutants in the populated urban area. Carefully planning street layout and canyon geometry while considering traffic demand as well as local weather patterns may significantly reduce inhalation of unhealthy air by urban residents.

A Numerical Simulation of Traffic-Related Air Pollution Exposures in Urban Street Canyons

NASA Astrophysics Data System (ADS)

Liu, J.; Fu, X.; Tao, S.

2016-12-01

Urban street canyons are usually associated with intensive vehicle emissions. However, the high buildings successively along both sides of a street block the dispersion of traffic-generated air pollutants, which enhances human exposure and adversely affects human health. In this study, an urban scale traffic pollution dispersion model is developed with the consideration of street distribution, canyon geometry, background meteorology, traffic assignment, traffic emissions and air pollutant dispersion. Vehicle exhausts generated from traffic flows will first disperse inside a street canyon along the micro-scale wind field (generated by computational fluid dynamics (CFD) model) and then leave the street canyon and further disperse over the urban area. On the basis of this model, the effects of canyon geometry on the distribution of NOx and CO from traffic emissions were studied over the center of Beijing, China. We found that an increase of building height along the streets leads to higher pollution levels inside streets and lower pollution levels outside, resulting in higher domain-averaged concentrations over the area. In addition, street canyons with equal (or highly uneven) building heights on two sides of a street tend to lower the urban-scale air pollution concentrations at pedestrian level. Our results indicate that canyon geometry strongly influences human exposure to traffic pollutants in the populated urban area. Carefully planning street layout and canyon geometry in consideration of traffic demand as well as local weather pattern may significantly reduce the chances of unhealthy air being inhaled by urban residents.

Electroluminescence from InGaN/GaN multi-quantum-wells nanorods light-emitting diodes positioned by non-uniform electric fields.

PubMed

Park, Hyunik; Kim, Byung-Jae; Kim, Jihyun

2012-11-05

We report that the nanorod light-emitting diodes (LEDs) with InGaN/GaN multi-quantum-wells (MQWs) emitted bright electroluminescence (EL) after they were positioned and aligned by non-uniform electric fields. Firstly, thin film LED structures with MQWs on sapphire substrate were coated with SiO(2) nanospheres, followed by inductively-coupled plasma etch to create nanorod-shapes with MQWs, which were transferred to the pre-patterned SiO(2)/Si wafer. This method allowed us to obtain nanorod LEDs with uniform length, diameter and qualities. Dielectrophoretic force created by non-uniform electric field was very effective at positioning the processed nanorods on the pre-patterned contacts. After aligned by non-uniform electric field, we observed bright EL from many nanorods, which had both cases (p-GaN/MQWs/n-GaN or n-GaN/MQWs/p-GaN). Therefore, bright ELs at different locations were observed under the various bias conditions.

Effect of aerated concrete blockwork joints on the heat transfer performance uniformity

NASA Astrophysics Data System (ADS)

Pukhkal, Viktor; Murgul, Vera

2018-03-01

Analysis of data on the effect of joints of the aerated concrete blocks on the heat transfer uniformity of exterior walls was carried out. It was concluded, that the values of the heat transfer performance uniformity factor in the literature sources were obtained for the regular fragment of a wall construction by approximate addition of thermal conductivities. Heat flow patterns for the aerated concrete exterior walls amid different values of the thermal conductivity factors and design ambient air temperature of -26 °C were calculated with the use of "ELCUT" software for modelling of thermal patterns by finite element method. There were defined the values for the heat transfer performance uniformity factor, reduced total thermal resistance and heat-flux density for the exterior walls. The calculated values of the heat transfer performance uniformity factors, as a function of the coefficient of thermal conductivity of aerated concrete blocks, differ from the known data by a more rigorous thermal and physical substantiation.

Epidemiologic Pattern of Fatal Traffic Injuries among Iranian Drivers; 2004–2010

PubMed Central

BAKHTIYARI, Mahmood; MEHMANDAR, Mohammad Reza; RIAHI, Seyed Mohammad; MANSOURNIA, Mohammad Ali; SARTIPI, Majid; BAHADORIMONFARED, Ayad

2016-01-01

Background: Due to their specific nature, such as high incidence, high intensity and direct involvement of all members of society, traffic injuries are of particular importance. Through a mega data, this study investigated the epidemiological aspects and depict current situation of road traffic injuries in Iran. Methods: Using legal medicine and traffic police data, deaths from road traffic injuries in men were predicted through determining the most appropriate model for death using time series statistical models; and then most important human factors associated with it in a period of 6 yr in Iran was analyzed using multi-nominal regression model. Results: The frequency of deaths from traffic injuries in the last seven years was 172,834 cases and the number of deaths at the accident scene was 42798 cases, of which 24.24% (41,971 cases) were recorded by the Traffic Police experts. Death rate from traffic injuries has been declined from 38 cases per 100,000 people in 2004 to 31 cases per 100,000 people between 2009 and 2010. Fatigue and sleepiness (AOR=10.36, 95% CI: 8.41–13.3) was the most significant human risk factors for death outcome in the urban and suburban traffic injuries. According to the predictions, the death rate is about 16488 (CI 95%, 8531–24364) for the year 2012. Conclusion: Despite all measures to prevent such injuries, even fatal injuries have still a high incidence. Intervention in the human risk factors field would be more effective due to their important roles in traffic injuries in Iran. PMID:27252920

Modeling the effect of microscopic driving behaviors on Kerner's time-delayed traffic breakdown at traffic signal using cellular automata

NASA Astrophysics Data System (ADS)

Wang, Yang; Chen, Yan-Yan

2016-12-01

The signalized traffic is considerably complex due to the fact that various driving behaviors have emerged to respond to traffic signals. However, the existing cellular automaton models take the signal-vehicle interactions into account inadequately, resulting in a potential risk that vehicular traffic flow dynamics may not be completely explored. To remedy this defect, this paper proposes a more realistic cellular automaton model by incorporating a number of the driving behaviors typically observed when the vehicles are approaching a traffic light. In particular, the anticipatory behavior proposed in this paper is realized with a perception factor designed by considering the vehicle speed implicitly and the gap to its preceding vehicle explicitly. Numerical simulations have been performed based on a signal controlled road which is partitioned into three sections according to the different reactions of drivers. The effects of microscopic driving behaviors on Kerner's time-delayed traffic breakdown at signal (Kerner 2011, 2013) have been investigated with the assistance of spatiotemporal pattern and trajectory analysis. Furthermore, the contributions of the driving behaviors on the traffic breakdown have been statistically examined. Finally, with the activation of the anticipatory behavior, the influences of the other driving behaviors on the formation of platoon have been investigated in terms of the number of platoons, the averaged platoon size, and the averaged flow rate.

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.

A traffic priority language for collision-free navigation of autonomous mobile robots in dynamic environments.

PubMed

Bourbakis, N G

1997-01-01

This paper presents a generic traffic priority language, called KYKLOFORTA, used by autonomous robots for collision-free navigation in a dynamic unknown or known navigation space. In a previous work by X. Grossmman (1988), a set of traffic control rules was developed for the navigation of the robots on the lines of a two-dimensional (2-D) grid and a control center coordinated and synchronized their movements. In this work, the robots are considered autonomous: they are moving anywhere and in any direction inside the free space, and there is no need of a central control to coordinate and synchronize them. The requirements for each robot are i) visual perception, ii) range sensors, and iii) the ability of each robot to detect other moving objects in the same free navigation space, define the other objects perceived size, their velocity and their directions. Based on these assumptions, a traffic priority language is needed for each robot, making it able to decide during the navigation and avoid possible collision with other moving objects. The traffic priority language proposed here is based on a set of primitive traffic priority alphabet and rules which compose pattern of corridors for the application of the traffic priority rules.

Simple cellular automaton model for traffic breakdown, highway capacity, and synchronized flow.

PubMed

Kerner, Boris S; Klenov, Sergey L; Schreckenberg, Michael

2011-10-01

We present a simple cellular automaton (CA) model for two-lane roads explaining the physics of traffic breakdown, highway capacity, and synchronized flow. The model consists of the rules "acceleration," "deceleration," "randomization," and "motion" of the Nagel-Schreckenberg CA model as well as "overacceleration through lane changing to the faster lane," "comparison of vehicle gap with the synchronization gap," and "speed adaptation within the synchronization gap" of Kerner's three-phase traffic theory. We show that these few rules of the CA model can appropriately simulate fundamental empirical features of traffic breakdown and highway capacity found in traffic data measured over years in different countries, like characteristics of synchronized flow, the existence of the spontaneous and induced breakdowns at the same bottleneck, and associated probabilistic features of traffic breakdown and highway capacity. Single-vehicle data derived in model simulations show that synchronized flow first occurs and then self-maintains due to a spatiotemporal competition between speed adaptation to a slower speed of the preceding vehicle and passing of this slower vehicle. We find that the application of simple dependences of randomization probability and synchronization gap on driving situation allows us to explain the physics of moving synchronized flow patterns and the pinch effect in synchronized flow as observed in real traffic data.

Electrical Field Guided Electrospray Deposition for Production of Gradient Particle Patterns.

PubMed

Yan, Wei-Cheng; Xie, Jingwei; Wang, Chi-Hwa

2018-06-06

Our previous work demonstrated the uniform particle pattern formation on the substrates using electrical field guided electrospray deposition. In this work, we reported for the first time the fabrication of gradient particle patterns on glass slides using an additional point, line, or bar electrode based on our previous electrospray deposition configuration. We also demonstrated that the polydimethylsiloxane (PDMS) coating could result in the formation of uniform particle patterns instead of gradient particle patterns on glass slides using the same experimental setup. Meanwhile, we investigated the effect of experimental configurations on the gradient particle pattern formation by computational simulation. The simulation results are in line with experimental observations. The formation of gradient particle patterns was ascribed to the gradient of electric field and the corresponding focusing effect. Cell patterns can be formed on the particle patterns deposited on PDMS-coated glass slides. The formed particle patterns hold great promise for high-throughput screening of biomaterial-cell interactions and sensing.

Bifurcation analysis of a heterogeneous traffic flow model

NASA Astrophysics Data System (ADS)

Wang, Yu-Qing; Yan, Bo-Wen; Zhou, Chao-Fan; Li, Wei-Kang; Jia, Bin

2018-03-01

In this work, a heterogeneous traffic flow model coupled with the periodic boundary condition is proposed. Based on the previous models, a heterogeneous system composed of more than one kind of vehicles is considered. By bifurcation analysis, bifurcation patterns of the heterogeneous system are discussed in three situations in detail and illustrated by diagrams of bifurcation patterns. Besides, the stability analysis of the heterogeneous system is performed to test its anti-interference ability. The relationship between the number of vehicles and the stability is obtained. Furthermore, the attractor analysis is applied to investigate the nature of the heterogeneous system near its steady-state neighborhood. Phase diagrams of the process of the heterogeneous system from initial state to equilibrium state are intuitively presented.

No evidence of a threshold in traffic volume affecting road-kill mortality at a large spatio-temporal scale

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

Grilo, Clara, E-mail: clarabentesgrilo@gmail.com; Centro Brasileiro de Estudos em Ecologia de Estradas, Departamento de Biologia, Universidade Federal de Lavras, Campus Universitário, 37200-000 Lavras, Minas Gerais; Ferreira, Flavio Zanchetta

Previous studies have found that the relationship between wildlife road mortality and traffic volume follows a threshold effect on low traffic volume roads. We aimed at evaluating the response of several species to increasing traffic intensity on highways over a large geographic area and temporal period. We used data of four terrestrial vertebrate species with different biological and ecological features known by their high road-kill rates: the barn owl (Tyto alba), hedgehog (Erinaceus europaeus), red fox (Vulpes vulpes) and European rabbit (Oryctolagus cuniculus). Additionally, we checked whether road-kill likelihood varies when traffic patterns depart from the average. We used annualmore » average daily traffic (AADT) and road-kill records observed along 1000 km of highways in Portugal over seven consecutive years (2003–2009). We fitted candidate models using Generalized Linear Models with a binomial distribution through a sample unit of 1 km segments to describe the effect of traffic on the probability of finding at least one victim in each segment during the study. We also assigned for each road-kill record the traffic of that day and the AADT on that year to test for differences using Paired Student's t-test. Mortality risk declined significantly with traffic volume but varied among species: the probability of finding road-killed red foxes and rabbits occurs up to moderate traffic volumes (< 20,000 AADT) whereas barn owls and hedgehogs occurred up to higher traffic volumes (40,000 AADT). Perception of risk may explain differences in responses towards high traffic highway segments. Road-kill rates did not vary significantly when traffic intensity departed from the average. In summary, we did not find evidence of traffic thresholds for the analysed species and traffic intensities. We suggest mitigation measures to reduce mortality be applied in particular on low traffic roads (< 5000 AADT) while additional measures to reduce barrier effects should take into account species-specific behavioural traits. - Highlights: • Traffic and road-kills were analysed along 1000 km of highways over seven years. • Mortality risk declined significantly with traffic volume. • Perception of risk may explain different responses towards high traffic sections. • Reducing barrier effects should take into account species behavioural traits.« less

Insertion of two-dimensional photonic crystal pattern on p-GaN layer of GaN-based light-emitting diodes using bi-layer nanoimprint lithography.

PubMed

Byeon, Kyeong-Jae; Hwang, Seon-Yong; Hong, Chang-Hee; Baek, Jong Hyeob; Lee, Heon

2008-10-01

Nanoimprint lithography (NIL) was adapted to fabricate two-dimensional (2-D) photonic crystal (PC) pattern on the p-GaN layer of InGaN/GaN multi quantum well light-emitting diodes (LEDs) structure to improve the light extraction efficiency. For the uniform transfer of the PC pattern, a bi-layer imprinting method with liquid phase resin was used. The p-GaN layer was patterned with a periodic array of holes by an inductively coupled plasma etching process, based on SiCl4/Ar plasmas. As a result, 2-D photonic crystal patterns with 144 nm, 200 nm and 347 nm diameter holes were uniformly formed on the p-GaN layer and the photoluminescence (PL) intensity of each patterned LED samples was increased by more than 2.6 times, as compared to that of the un-patterned LED sample.

Traffic Sign Recognition with Invariance to Lighting in Dual-Focal Active Camera System

NASA Astrophysics Data System (ADS)

Gu, Yanlei; Panahpour Tehrani, Mehrdad; Yendo, Tomohiro; Fujii, Toshiaki; Tanimoto, Masayuki

In this paper, we present an automatic vision-based traffic sign recognition system, which can detect and classify traffic signs at long distance under different lighting conditions. To realize this purpose, the traffic sign recognition is developed in an originally proposed dual-focal active camera system. In this system, a telephoto camera is equipped as an assistant of a wide angle camera. The telephoto camera can capture a high accuracy image for an object of interest in the view field of the wide angle camera. The image from the telephoto camera provides enough information for recognition when the accuracy of traffic sign is low from the wide angle camera. In the proposed system, the traffic sign detection and classification are processed separately for different images from the wide angle camera and telephoto camera. Besides, in order to detect traffic sign from complex background in different lighting conditions, we propose a type of color transformation which is invariant to light changing. This color transformation is conducted to highlight the pattern of traffic signs by reducing the complexity of background. Based on the color transformation, a multi-resolution detector with cascade mode is trained and used to locate traffic signs at low resolution in the image from the wide angle camera. After detection, the system actively captures a high accuracy image of each detected traffic sign by controlling the direction and exposure time of the telephoto camera based on the information from the wide angle camera. Moreover, in classification, a hierarchical classifier is constructed and used to recognize the detected traffic signs in the high accuracy image from the telephoto camera. Finally, based on the proposed system, a set of experiments in the domain of traffic sign recognition is presented. The experimental results demonstrate that the proposed system can effectively recognize traffic signs at low resolution in different lighting conditions.

Calculation of x-ray scattering patterns from nanocrystals at high x-ray intensity

PubMed Central

Abdullah, Malik Muhammad; Jurek, Zoltan; Son, Sang-Kil; Santra, Robin

2016-01-01

We present a generalized method to describe the x-ray scattering intensity of the Bragg spots in a diffraction pattern from nanocrystals exposed to intense x-ray pulses. Our method involves the subdivision of a crystal into smaller units. In order to calculate the dynamics within every unit, we employ a Monte-Carlo-molecular dynamics-ab-initio hybrid framework using real space periodic boundary conditions. By combining all the units, we simulate the diffraction pattern of a crystal larger than the transverse x-ray beam profile, a situation commonly encountered in femtosecond nanocrystallography experiments with focused x-ray free-electron laser radiation. Radiation damage is not spatially uniform and depends on the fluence associated with each specific region inside the crystal. To investigate the effects of uniform and non-uniform fluence distribution, we have used two different spatial beam profiles, Gaussian and flattop. PMID:27478859

On the mechanism of pattern formation in glow dielectric barrier discharge

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

Qiao, Yajun; Li, Ben; Ouyang, Jiting, E-mail: jtouyang@bit.edu.cn

2016-01-15

The formation mechanism of pattern in glow dielectric barrier discharge is investigated by two-dimensional fluid modeling. Experimental results are shown for comparison. The simulation results show that the non-uniform distribution of space charges makes the discharge be enhanced in the high-density region but weakened in its neighborhood, which is considered as an activation-inhibition effect. This effect shows through during a current pulse (one discharge event) but also in a certain period of time after discharge that determines a driving frequency range for the non-uniformity of space charges to be enhanced. The effects of applied voltage, surface charge, electrode boundary, andmore » external field are also discussed. All these factors affect the formation of dielectric-barrier-discharge pattern by changing the distribution or the dynamics of space charges and hence the activation-inhibition effect of non-uniform space charges.« less

Coded aperture imaging with self-supporting uniformly redundant arrays

DOEpatents

Fenimore, Edward E.

1983-01-01

A self-supporting uniformly redundant array pattern for coded aperture imaging. The present invention utilizes holes which are an integer times smaller in each direction than holes in conventional URA patterns. A balance correlation function is generated where holes are represented by 1's, nonholes are represented by -1's, and supporting area is represented by 0's. The self-supporting array can be used for low energy applications where substrates would greatly reduce throughput. The balance correlation response function for the self-supporting array pattern provides an accurate representation of the source of nonfocusable radiation.

Population-Level Exposure to Particulate Air Pollution during Active Travel: Planning for Low-Exposure, Health-Promoting Cities

PubMed Central

Hankey, Steve; Lindsey, Greg; Marshall, Julian D.

2016-01-01

Background: Providing infrastructure and land uses to encourage active travel (i.e., bicycling and walking) are promising strategies for designing health-promoting cities. Population-level exposure to air pollution during active travel is understudied. Objectives: Our goals were a) to investigate population-level patterns in exposure during active travel, based on spatial estimates of bicycle traffic, pedestrian traffic, and particulate concentrations; and b) to assess how those exposure patterns are associated with the built environment. Methods: We employed facility–demand models (active travel) and land use regression models (particulate concentrations) to estimate block-level (n = 13,604) exposure during rush-hour (1600–1800 hours) in Minneapolis, Minnesota. We used the model-derived estimates to identify land use patterns and characteristics of the street network that are health promoting. We also assessed how exposure is correlated with indicators of health disparities (e.g., household income, proportion of nonwhite residents). Our work uses population-level rates of active travel (i.e., traffic flows) rather than the probability of walking or biking (i.e., “walkability” or “bikeability”) to assess exposure. Results: Active travel often occurs on high-traffic streets or near activity centers where particulate concentrations are highest (i.e., 20–42% of active travel occurs on blocks with high population-level exposure). Only 2–3% of blocks (3–8% of total active travel) are “sweet spots” (i.e., high active travel, low particulate concentrations); sweet spots are located a) near but slightly removed from the city-center or b) on off-street trails. We identified 1,721 blocks (~ 20% of local roads) where shifting active travel from high-traffic roads to adjacent low-traffic roads would reduce exposure by ~ 15%. Active travel is correlated with population density, land use mix, open space, and retail area; particulate concentrations were mostly unchanged with land use. Conclusions: Public health officials and urban planners may use our findings to promote healthy transportation choices. When designing health-promoting cities, benefits (physical activity) as well as hazards (air pollution) should be evaluated. Citation: Hankey S, Lindsey G, Marshall JD. 2017. Population-level exposure to particulate air pollution during active travel: planning for low-exposure, health-promoting cities. Environ Health Perspect 125:–534; http://dx.doi.org/10.1289/EHP442 PMID:27713109

Daylight saving time can decrease the frequency of wildlife-vehicle collisions.

PubMed

Ellis, William A; FitzGibbon, Sean I; Barth, Benjamin J; Niehaus, Amanda C; David, Gwendolyn K; Taylor, Brendan D; Matsushige, Helena; Melzer, Alistair; Bercovitch, Fred B; Carrick, Frank; Jones, Darryl N; Dexter, Cathryn; Gillett, Amber; Predavec, Martin; Lunney, Dan; Wilson, Robbie S

2016-11-01

Daylight saving time (DST) could reduce collisions with wildlife by changing the timing of commuter traffic relative to the behaviour of nocturnal animals. To test this idea, we tracked wild koalas (Phascolarctos cinereus) in southeast Queensland, where koalas have declined by 80% in the last 20 years, and compared their movements with traffic patterns along roads where they are often killed. Using a simple model, we found that DST could decrease collisions with koalas by 8% on weekdays and 11% at weekends, simply by shifting the timing of traffic relative to darkness. Wildlife conservation and road safety should become part of the debate on DST. © 2016 The Author(s).

A Performance Assessment of a Tactical Airborne Separation Assistance System using Realistic, Complex Traffic Flows

NASA Technical Reports Server (NTRS)

Smith, Jeremy C.; Neitzke, Kurt W.; Bussink, Frank J. L.

2008-01-01

This paper presents the results from a study that investigates the performance of aspects of an Airborne Separation Assistance System (ASAS) under varying demand levels using realistic traffic patterns. This study only addresses the tactical aspects of an ASAS using aircraft state data (latitude, longitude, altitude, heading and speed) to detect and resolve projected conflicts. The main focus of this paper is to determine the extent to which sole reliance on the proposed tactical ASAS can maintain aircraft separation at demand levels up to three times current traffic. The effect of mixing ASAS equipped aircraft with non-equipped aircraft that do not have the capability to self-separate is also investigated.

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

Weeks, R.; Briggs, M.; Gyenes, L.

A study carried out to assist the design of an infrastructure for refuelling battery electric cars is described. A one-week survey by questionnaire of all filling stations in the area yielded estimates of petrol sales at individual stations together with number of customers served and quantities purchased per customer. A computer simulation of traffic flow attempted to predict weekly petrol sales in nine sectors of the town. A one-day count of traffic and petrol buyers at a single filling station was related to the traffic flows in the whole town to give a typical daily pattern of petrol buyers. Finallymore » a simulation procedure was developed to investigate the effects of demand on queue length at battery exchange stations.« less

Traffic Behavior Recognition Using the Pachinko Allocation Model

PubMed Central

Huynh-The, Thien; Banos, Oresti; Le, Ba-Vui; Bui, Dinh-Mao; Yoon, Yongik; Lee, Sungyoung

2015-01-01

CCTV-based behavior recognition systems have gained considerable attention in recent years in the transportation surveillance domain for identifying unusual patterns, such as traffic jams, accidents, dangerous driving and other abnormal behaviors. In this paper, a novel approach for traffic behavior modeling is presented for video-based road surveillance. The proposed system combines the pachinko allocation model (PAM) and support vector machine (SVM) for a hierarchical representation and identification of traffic behavior. A background subtraction technique using Gaussian mixture models (GMMs) and an object tracking mechanism based on Kalman filters are utilized to firstly construct the object trajectories. Then, the sparse features comprising the locations and directions of the moving objects are modeled by PAM into traffic topics, namely activities and behaviors. As a key innovation, PAM captures not only the correlation among the activities, but also among the behaviors based on the arbitrary directed acyclic graph (DAG). The SVM classifier is then utilized on top to train and recognize the traffic activity and behavior. The proposed model shows more flexibility and greater expressive power than the commonly-used latent Dirichlet allocation (LDA) approach, leading to a higher recognition accuracy in the behavior classification. PMID:26151213

Impact of deformed extreme-ultraviolet pellicle in terms of CD uniformity

NASA Astrophysics Data System (ADS)

Kim, In-Seon; Yeung, Michael; Barouch, Eytan; Oh, Hye-Keun

2015-07-01

The usage of the extreme ultraviolet (EUV) pellicle is regarded as the solution for defect control since it can protect the mask from airborne debris. However some obstacles disrupt real-application of the pellicle such as structural weakness, thermal damage and so on. For these reasons, flawless fabrication of the pellicle is impossible. In this paper, we discuss the influence of deformed pellicle in terms of non-uniform intensity distribution and critical dimension (CD) uniformity. It was found that non-uniform intensity distribution is proportional to local tilt angle of pellicle and CD variation was linearly proportional to transmission difference. When we consider the 16 nm line and space pattern with dipole illumination (σc=0.8, σr=0.1, NA=0.33), the transmission difference (max-min) of 0.7 % causes 0.1 nm CD uniformity. Influence of gravity caused deflection to the aerial image is small enough to ignore. CD uniformity is less than 0.1 nm even for the current gap of 2 mm between mask and pellicle. However, heat caused EUV pellicle wrinkle might cause serious image distortion because a wrinkle of EUV pellicle causes a transmission loss variation as well as CD non-uniformity. In conclusion, local angle of a wrinkle, not a period or an amplitude of a wrinkle is a main factor to CD uniformity, and local angle of less than ~270 mrad is needed to achieve 0.1 nm CD uniformity with 16 nm L/S pattern.

Thin films with disordered nanohole patterns for solar radiation absorbers

NASA Astrophysics Data System (ADS)

Fang, Xing; Lou, Minhan; Bao, Hua; Zhao, C. Y.

2015-06-01

The radiation absorption in thin films with three disordered nanohole patterns, i.e., random position, non-uniform radius, and amorphous pattern, are numerically investigated by finite-difference time-domain (FDTD) simulations. Disorder can alter the absorption spectra and has an impact on the broadband absorption performance. Compared to random position and non-uniform radius nanoholes, amorphous pattern can induce a much better integrated absorption. The power density spectra indicate that amorphous pattern nanoholes reduce the symmetry and provide more resonance modes that are desired for the broadband absorption. The application condition for amorphous pattern nanoholes shows that they are much more appropriate in absorption enhancement for weak absorption materials. Amorphous silicon thin films with disordered nanohole patterns are applied in solar radiation absorbers. Four configurations of thin films with different nanohole patterns show that interference between layers in absorbers will change the absorption performance. Therefore, it is necessary to optimize the whole radiation absorbers although single thin film with amorphous pattern nanohole has reached optimal absorption.

A phantom road experiment reveals traffic noise is an invisible source of habitat degradation

PubMed Central

Ware, Heidi E.; McClure, Christopher J. W.; Carlisle, Jay D.; Barber, Jesse R.

2015-01-01

Decades of research demonstrate that roads impact wildlife and suggest traffic noise as a primary cause of population declines near roads. We created a “phantom road” using an array of speakers to apply traffic noise to a roadless landscape, directly testing the effect of noise alone on an entire songbird community during autumn migration. Thirty-one percent of the bird community avoided the phantom road. For individuals that stayed despite the noise, overall body condition decreased by a full SD and some species showed a change in ability to gain body condition when exposed to traffic noise during migratory stopover. We conducted complementary laboratory experiments that implicate foraging-vigilance behavior as one mechanism driving this pattern. Our results suggest that noise degrades habitat that is otherwise suitable, and that the presence of a species does not indicate the absence of an impact. PMID:26324924

[Attention to speed and guide traffic signs with eye movements].

PubMed

Conchillo Jiménez, Ángela; Pérez-Moreno, Elisa; Recarte Goldaracena, Miguel Ángel

2010-11-01

The goal of this research is to describe the visual search patterns for diverse traffic signs. Twelve drivers of both genders and different driving experience levels took part in real driving research with an instrumented car provided with an eye-tracking system. Looking at signs has a weak relation with speed reduction in cases where actual driving speed was higher. Nevertheless, among the people who looked at the sign, the percentage of those who reduce the speed below the limit is greater than of those who do not look at the sign. Guide traffic signs, particularly those mounted over the road, are more frequently glanced at than speed limit signs, with a glance duration of more than one second, in sequences of more than two consecutive fixations. Implications for driving and the possibilities and limitations of eye movement analysis for traffic sign research are discussed.

Fractionation and mobility of Cu, Fe, Mn, Pb and Zn in the road dust retained on noise barriers along expressway - a potential tool for determining the effects of driving conditions on speciation of emitted particulate metals.

PubMed

Świetilik, Ryszard; Trojanowska, Marzena; Strzelecka, Monika; Bocho-Janiszewska, Anita

2015-01-01

Road dust (RD) retained on noise barriers was used as a monitor of emission of traffic-related metals from expressway. By using SEM/EDX analysis it has been revealed that the main components of this particulate were irregular fine aggregates and tire debris with a ragged porous structure and with inclusions derived from the road surface. The results of chemical fractionation showed that driving conditions influence strongly a distribution pattern of Cu, whereas the atmospheric corrosion process affects a distribution pattern of Zn. The distribution pattern of Cu originating only from vehicle braking emission was “isolated” from the distribution pattern of road traffic copper. The predicted comparative mobilities of the emitted metals form the order: Zn > Cu ≈ Mn > Pb > Fe. The high mobility of zinc (K = 0.61)may create a current inhalation hazard and may be a source of future environmental hazard in the areas adjacent to heavily trafficked roads.

Experimental Performance of a Genetic Algorithm for Airborne Strategic Conflict Resolution

NASA Technical Reports Server (NTRS)

Karr, David A.; Vivona, Robert A.; Roscoe, David A.; DePascale, Stephen M.; Consiglio, Maria

2009-01-01

The Autonomous Operations Planner, a research prototype flight-deck decision support tool to enable airborne self-separation, uses a pattern-based genetic algorithm to resolve predicted conflicts between the ownship and traffic aircraft. Conflicts are resolved by modifying the active route within the ownship s flight management system according to a predefined set of maneuver pattern templates. The performance of this pattern-based genetic algorithm was evaluated in the context of batch-mode Monte Carlo simulations running over 3600 flight hours of autonomous aircraft in en-route airspace under conditions ranging from typical current traffic densities to several times that level. Encountering over 8900 conflicts during two simulation experiments, the genetic algorithm was able to resolve all but three conflicts, while maintaining a required time of arrival constraint for most aircraft. Actual elapsed running time for the algorithm was consistent with conflict resolution in real time. The paper presents details of the genetic algorithm s design, along with mathematical models of the algorithm s performance and observations regarding the effectiveness of using complimentary maneuver patterns when multiple resolutions by the same aircraft were required.

Experimental Performance of a Genetic Algorithm for Airborne Strategic Conflict Resolution

NASA Technical Reports Server (NTRS)

Karr, David A.; Vivona, Robert A.; Roscoe, David A.; DePascale, Stephen M.; Consiglio, Maria

2009-01-01

The Autonomous Operations Planner, a research prototype flight-deck decision support tool to enable airborne self-separation, uses a pattern-based genetic algorithm to resolve predicted conflicts between the ownship and traffic aircraft. Conflicts are resolved by modifying the active route within the ownship's flight management system according to a predefined set of maneuver pattern templates. The performance of this pattern-based genetic algorithm was evaluated in the context of batch-mode Monte Carlo simulations running over 3600 flight hours of autonomous aircraft in en-route airspace under conditions ranging from typical current traffic densities to several times that level. Encountering over 8900 conflicts during two simulation experiments, the genetic algorithm was able to resolve all but three conflicts, while maintaining a required time of arrival constraint for most aircraft. Actual elapsed running time for the algorithm was consistent with conflict resolution in real time. The paper presents details of the genetic algorithm's design, along with mathematical models of the algorithm's performance and observations regarding the effectiveness of using complimentary maneuver patterns when multiple resolutions by the same aircraft were required.

Traffic-engineering-aware shortest-path routing and its application in IP-over-WDM networks [Invited

NASA Astrophysics Data System (ADS)

Lee, Youngseok; Mukherjee, Biswanath

2004-03-01

Single shortest-path routing is known to perform poorly for Internet traffic engineering (TE) where the typical optimization objective is to minimize the maximum link load. Splitting traffic uniformly over equal-cost multiple shortest paths in open shortest path first and intermediate system-intermediate system protocols does not always minimize the maximum link load when multiple paths are not carefully selected for the global traffic demand matrix. However, a TE-aware shortest path among all the equal-cost multiple shortest paths between each ingress-egress pair can be selected such that the maximum link load is significantly reduced. IP routers can use the globally optimal TE-aware shortest path without any change to existing routing protocols and without any serious configuration overhead. While calculating TE-aware shortest paths, the destination-based forwarding constraint at a node should be satisfied, because an IP router will forward a packet to the next hop toward the destination by looking up the destination prefix. We present a mathematical problem formulation for finding a set of TE-aware shortest paths for the given network as an integer linear program, and we propose a simple heuristic for solving large instances of the problem. Then we explore the usage of our proposed algorithm for the integrated TE method in IP-over-WDM networks. The proposed algorithm is evaluated through simulations in IP networks as well as in IP-over-WDM networks.

Quantitative assessment of commercial filter 'aids' for red-green colour defectives.

PubMed

Moreland, Jack D; Westland, Steven; Cheung, Vien; Dain, Steven J

2010-09-01

The claims made for 43 commercial filter 'aids', that they improve the colour discrimination of red-green colour defectives, are assessed for protanomaly and deuteranomaly by changes in the colour spacing of traffic signals (European Standard EN 1836:2005) and of the Farnsworth D15 test. Spectral transmittances of the 'aids' are measured and tristimulus values with and without 'aids' are computed using cone fundamentals and the spectral power distributions of either the D15 chips illuminated by CIE Illuminant C or of traffic signals. Chromaticities (l,s) are presented in cone excitation diagrams for protanomaly and deuteranomaly in terms of the relative excitation of their long (L), medium (M) and short (S) wavelength-sensitive cones. After correcting for non-uniform colour spacing in these diagrams, standard deviations parallel to the l and s axes are computed and enhancement factors E(l) and E(s) are derived as the ratio of 'aided' to 'unaided' standard deviations. Values of E(l) for traffic signals with most 'aids' are <1 and many do not meet the European signal detection standard. A few 'aids' have expansive E(l) factors but with inadequate utility: the largest being 1.2 for traffic signals and 1.3 for the D15 colours. Analyses, replicated for 19 'aids' from one manufacturer using 658 Munsell colours inside the D15 locus, yield E(l) factors within 1% of those found for the 16 D15 colours. © 2010 The Authors, Ophthalmic and Physiological Optics © 2010 The College of Optometrists.

Combined action of transverse oscillations and uniform cross-flow on vortex formation and pattern of a circular cylinder

NASA Astrophysics Data System (ADS)

Lam, K. M.; Liu, P.; Hu, J. C.

2010-07-01

This paper attempts to study the roles of lateral cylinder oscillations and a uniform cross-flow in the vortex formation and wake modes of an oscillating circular cylinder. A circular cylinder is given lateral oscillations of varying amplitudes (between 0.28 and 1.42 cylinder-diameters) in a slow uniform flow stream (Reynolds number=284) to produce the 2S, 2P and P+S wake modes. Detailed flow information is obtained with time-resolved particle-image velocimetry and the phase-locked averaging techniques. In the 2S and 2P mode, the flow speeds relative to the cylinder movement are less than the uniform flow velocity and it is found that initial formation of a vortex is caused by shear-layer separation of the uniform flow on the cylinder. Subsequent development of the shear-layer vortices is affected by the lateral cylinder movement. At small cylinder oscillation amplitudes, vortices are shed in synchronization with the cylinder movement, resulting in the 2S mode. The 2P mode occurs at larger cylinder oscillation amplitudes at which each shear-layer vortex is found to undergo intense stretching and eventual bifurcation into two separate vortices. The P+S mode occurs when the cylinder moving speeds are, for most of the time, higher than the speed of the uniform flow. These situations are found at fast and large-amplitude cylinder oscillations in which the flow relative to the cylinder movement takes over the uniform flow in governing the initial vortex formation. The formation stages of vortices from the cylinder are found to bear close resemblance to those of a vortex street pattern of a cylinder oscillating in an otherwise quiescent fluid at Keulegan-Carpenter numbers around 16. Vortices in the inclined vortex street pattern so formed are then convected downstream by the uniform flow as the vortex pairs in the 2P mode.

Developing a Minimum Data Set for an Information Management System to Study Traffic Accidents in Iran.

PubMed

Mohammadi, Ali; Ahmadi, Maryam; Gharagozlu, Alireza

2016-03-01

Each year, around 1.2 million people die in the road traffic incidents. Reducing traffic accidents requires an exact understanding of the risk factors associated with traffic patterns and behaviors. Properly analyzing these factors calls for a comprehensive system for collecting and processing accident data. The aim of this study was to develop a minimum data set (MDS) for an information management system to study traffic accidents in Iran. This descriptive, cross-sectional study was performed in 2014. Data were collected from the traffic police, trauma centers, medical emergency centers, and via the internet. The investigated resources for this study were forms, databases, and documents retrieved from the internet. Forms and databases were identical, and one sample of each was evaluated. The related internet-sourced data were evaluated in their entirety. Data were collected using three checklists. In order to arrive at a consensus about the data elements, the decision Delphi technique was applied using questionnaires. The content validity and reliability of the questionnaires were assessed by experts' opinions and the test-retest method, respectively. An (MDS) of a traffic accident information management system was assigned to three sections: a minimum data set for traffic police with six classes, including 118 data elements; a trauma center with five data classes, including 57 data elements; and a medical emergency center, with 11 classes, including 64 data elements. Planning for the prevention of traffic accidents requires standardized data. As the foundation for crash prevention efforts, existing standard data infrastructures present policymakers and government officials with a great opportunity to strengthen and integrate existing accident information systems to better track road traffic injuries and fatalities.

Developing a Minimum Data Set for an Information Management System to Study Traffic Accidents in Iran

PubMed Central

Mohammadi, Ali; Ahmadi, Maryam; Gharagozlu, Alireza

2016-01-01

Background: Each year, around 1.2 million people die in the road traffic incidents. Reducing traffic accidents requires an exact understanding of the risk factors associated with traffic patterns and behaviors. Properly analyzing these factors calls for a comprehensive system for collecting and processing accident data. Objectives: The aim of this study was to develop a minimum data set (MDS) for an information management system to study traffic accidents in Iran. Materials and Methods: This descriptive, cross-sectional study was performed in 2014. Data were collected from the traffic police, trauma centers, medical emergency centers, and via the internet. The investigated resources for this study were forms, databases, and documents retrieved from the internet. Forms and databases were identical, and one sample of each was evaluated. The related internet-sourced data were evaluated in their entirety. Data were collected using three checklists. In order to arrive at a consensus about the data elements, the decision Delphi technique was applied using questionnaires. The content validity and reliability of the questionnaires were assessed by experts’ opinions and the test-retest method, respectively. Results: An (MDS) of a traffic accident information management system was assigned to three sections: a minimum data set for traffic police with six classes, including 118 data elements; a trauma center with five data classes, including 57 data elements; and a medical emergency center, with 11 classes, including 64 data elements. Conclusions: Planning for the prevention of traffic accidents requires standardized data. As the foundation for crash prevention efforts, existing standard data infrastructures present policymakers and government officials with a great opportunity to strengthen and integrate existing accident information systems to better track road traffic injuries and fatalities. PMID:27247791

Randomised controlled trial of site specific advice on school travel patterns.

PubMed

Rowland, D; DiGuiseppi, C; Gross, M; Afolabi, E; Roberts, I

2003-01-01

To evaluate the effect of site specific advice from a school travel coordinator on school travel patterns. Cluster randomised controlled trial of children attending 21 primary schools in the London boroughs of Camden and Islington. A post-intervention survey measured the proportion of children walking, cycling, or using public transport for travel to school, and the proportion of parents/carers very or quite worried about traffic and abduction. The proportion of schools that developed and implemented travel plans was assessed. One year post-intervention, nine of 11 intervention schools and none of 10 control schools had travel plans. Proportions of children walking, cycling, or using public transport on the school journey were similar in intervention and control schools. The proportion of parents who were very or quite worried about traffic danger was similar in the intervention (85%) and control groups (87%). However, after adjusting for baseline and other potential confounding factors we could not exclude the possibility of a modest reduction in parental concern about traffic danger as a result of the intervention. Having a school travel coordinator increased the production of school travel plans but there was no evidence that this changed travel patterns or reduced parental fears. Given the uncertainty about effectiveness, the policy of providing school travel coordinators should only be implemented within the context of a randomised controlled trial.

Coded aperture imaging with self-supporting uniformly redundant arrays. [Patent application

DOEpatents

Fenimore, E.E.

1980-09-26

A self-supporting uniformly redundant array pattern for coded aperture imaging. The invention utilizes holes which are an integer times smaller in each direction than holes in conventional URA patterns. A balance correlation function is generated where holes are represented by 1's, nonholes are represented by -1's, and supporting area is represented by 0's. The self-supporting array can be used for low energy applications where substrates would greatly reduce throughput.

Prediction of PM 10 concentrations at urban traffic intersections using semi-empirical box modelling with instantaneous velocity and acceleration

NASA Astrophysics Data System (ADS)

He, Hong-di; Lu, Wei-Zhen; Xue, Yu

2009-12-01

At urban traffic intersections, vehicles frequently stop with idling engines during the red-light period and speed up rapidly during the green-light period. The changes of driving patterns (i.e., idle, acceleration, deceleration and cruising patterns) generally produce uncertain emission. Additionally, the movement of pedestrians and the influence of wind further result in the random dispersion of pollutants. It is, therefore, too complex to simulate the effects of such dynamics on the resulting emission using conventional deterministic causal models. For this reason, a modified semi-empirical box model for predicting the PM 10 concentrations on roadsides is proposed in this paper. The model constitutes three parts, i.e., traffic, emission and dispersion components. The traffic component is developed using a generalized force traffic model to obtain the instantaneous velocity and acceleration when vehicles move through intersections. Hence the distribution of vehicle emission in street canyon during the green-light period is calculated. Then the dispersion component is investigated using a semi-empirical box model combining average wind speed, box height and background concentrations. With these considerations, the proposed model is applied and evaluated using measured data at a busy traffic intersection in Mong Kok, Hong Kong. In order to test the performance of the model, two situations, i.e., the data sets within a sunny day and between two sunny days, were selected to examine the model performance. The predicted values are generally well coincident with the observed data during different time slots except several values are overestimated or underestimated. Moreover, two types of vehicles, i.e., buses and petrol cars, are separately taken into account in the study. Buses are verified to contribute most to the emission in street canyons, which may be useful in evaluating the impact of vehicle emissions on the ambient air quality when there is a significant change in a specific vehicular population.

Moose, caribou, and grizzly bear distribution in relation to road traffic in Denali National Park, Alaska

USGS Publications Warehouse

Yost, A.C.; Wright, R.G.

2001-01-01

Park managers are concerned that moose (Alces alces), caribou (Rangifer tarandus), and grizzly bears (Ursus arctos) may be avoiding areas along the 130 km road through Denali National Park as a result of high traffic volume, thus decreasing opportunities for visitors to view wildlife. A wildlife monitoring system was developed in 1996 that used 19 landscape level viewsheds, stratified into four sections based on decreasing traffic along the road corridor. Data were collected from 22 samplings of all viewsheds during May-August in 1996 and 1997. In 1997, nine backcountry viewsheds were established in three different areas to determine whether density estimates for each species in the backcountry were higher than those for the same animals in similar road-corridor areas. Densities higher than those in the road corridor were found in one backcountry area for moose and in two backcountry areas for grizzly bears. None of the backcountry areas showed a higher density of caribou. We tested hypotheses that moose, caribou, and grizzly bear distributions were unrelated to the road and traffic. Moose sightings were lower than expected within 300 m of the road. More caribou and grizzly bears than expected occurred between 601 and 900 m from the road, while more moose and fewer caribou than expected occurred between 900 and 1200 m from the road. Bull moose in stratum 1 were distributed farther from the road than bulls and cows in stratum 4; cows in stratum 1 and bulls in stratum 2 were distributed farther from the road than cows in stratum 4. Grizzly bears in stratum 2 were distributed farther from the road than bears in stratum 3. The distribution of moose sightings suggests traffic avoidance, but the spatial pattern of preferred forage may have had more of an influence. Caribou and grizzly bear distributions indicated no pattern of traffic avoidance.

Characterization of traffic-related PM concentration distribution and fluctuation patterns in near-highway urban residential street canyons.

PubMed

Hahn, Intaek; Brixey, Laurie A; Wiener, Russell W; Henkle, Stacy W; Baldauf, Richard

2009-12-01

Analyses of outdoor traffic-related particulate matter (PM) concentration distribution and fluctuation patterns in urban street canyons within a microscale distance of less than 500 m from a highway source are presented as part of the results from the Brooklyn Traffic Real-Time Ambient Pollutant Penetration and Environmental Dispersion (B-TRAPPED) study. Various patterns of spatial and temporal changes in the street canyon PM concentrations were investigated using time-series data of real-time PM concentrations measured during multiple monitoring periods. Concurrent time-series data of local street canyon wind conditions and wind data from the John F. Kennedy (JFK) International Airport National Weather Service (NWS) were used to characterize the effects of various wind conditions on the behavior of street canyon PM concentrations.Our results suggest that wind direction may strongly influence time-averaged mean PM concentration distribution patterns in near-highway urban street canyons. The rooftop-level wind speeds were found to be strongly correlated with the PM concentration fluctuation intensities in the middle sections of the street blocks. The ambient turbulence generated by shifting local wind directions (angles) showed a good correlation with the PM concentration fluctuation intensities along the entire distance of the first and second street blocks only when the wind angle standard deviations were larger than 30 degrees. Within-canyon turbulent shearing, caused by fluctuating local street canyon wind speeds, showed no correlation with PM concentration fluctuation intensities. The time-averaged mean PM concentration distribution along the longitudinal distances of the street blocks when wind direction was mostly constantly parallel to the street was found to be similar to the distribution pattern for the entire monitoring period when wind direction fluctuated wildly. Finally, we showed that two different PM concentration metrics-time-averaged mean concentration and number of concentration peaks above a certain threshold level-can possibly lead to different assessments of spatial concentration distribution patterns.

A cross-sectional study of travel patterns of older adults in the USA during 2015: implications for mobility and traffic safety

PubMed Central

Shen, Sijun; Koech, Wilson; Feng, Jing; Rice, Thomas M; Zhu, Motao

2017-01-01

Background With an ever increasing population of older adults (65+ years) in the USA, a better understanding of this population’s travel patterns is needed to improve travel mobility and transportation safety. Objective In this study, we described the travel patterns of older adults in the USA during 2015. Methods Travel patterns of older adults (65–74 and 75+ years) were compared with younger adults (25–64 years) by frequency and proportion of daily trips. The daily trips of various age groups were estimated using the 2015 American Time Use Survey. Results The percentage of daily travellers was 88% for adults (25–64 years), 75% for adults (65–74 years) and 68% for adults (75+ years). While the percentage of privately owned vehicle (POV) drivers and average time of driving POVs decreased, the percentage of POV passengers increased as adults aged. Females were less likely to drive POVs and had decreased average daily driving time, but they were more likely to ride in POVs as passengers and had longer average daily riding times than their male counterparts across all age groups. Older adults were more likely to travel in the mornings and early afternoons (from 8:00 to 15:59) while younger adults were more likely to travel in the late afternoons and early evenings (from 16:00 to 19:59). Conclusions POV use is the predominant mode of transit in the USA. As adults age, the percentages of daily travellers and POV drivers decrease. This pattern is more apparent among females than males. This study delineated travel patterns of older adults using a 2015 national survey, and the findings facilitate traffic systems designers and policy-makers to develop and implement initiatives to accommodate older adults’ mobility needs and improve traffic safety. PMID:28801408

A cross-sectional study of travel patterns of older adults in the USA during 2015: implications for mobility and traffic safety.

PubMed

Shen, Sijun; Koech, Wilson; Feng, Jing; Rice, Thomas M; Zhu, Motao

2017-08-11

With an ever increasing population of older adults (65+ years) in the USA, a better understanding of this population's travel patterns is needed to improve travel mobility and transportation safety. In this study, we described the travel patterns of older adults in the USA during 2015. Travel patterns of older adults (65-74 and 75+ years) were compared with younger adults (25-64 years) by frequency and proportion of daily trips. The daily trips of various age groups were estimated using the 2015 American Time Use Survey. The percentage of daily travellers was 88% for adults (25-64 years), 75% for adults (65-74 years) and 68% for adults (75+ years). While the percentage of privately owned vehicle (POV) drivers and average time of driving POVs decreased, the percentage of POV passengers increased as adults aged. Females were less likely to drive POVs and had decreased average daily driving time, but they were more likely to ride in POVs as passengers and had longer average daily riding times than their male counterparts across all age groups. Older adults were more likely to travel in the mornings and early afternoons (from 8:00 to 15:59) while younger adults were more likely to travel in the late afternoons and early evenings (from 16:00 to 19:59). POV use is the predominant mode of transit in the USA. As adults age, the percentages of daily travellers and POV drivers decrease. This pattern is more apparent among females than males. This study delineated travel patterns of older adults using a 2015 national survey, and the findings facilitate traffic systems designers and policy-makers to develop and implement initiatives to accommodate older adults' mobility needs and improve traffic safety. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Increased illumination uniformity and reduced photodamage offered by the Lissajous scanning in fiber-optic two-photon endomicroscopy

NASA Astrophysics Data System (ADS)

Liang, Wenxuan; Murari, Kartikeya; Zhang, Yuying; Chen, Yongping; Li, Ming-Jun; Li, Xingde

2012-02-01

We compare the illumination uniformity and the associated effects of the spiral and Lissajous scanning patterns that are commonly used in an endomicroscope. Theoretical analyses and numerical simulations were first performed to quantitatively investigate the area illumination density in the spiral scanning pattern. The results revealed the potential problem of manifest photodamage due to the very high illumination density in the center of the spiral scan. Similar analyses of the Lissajous scanning pattern, which can be conveniently implemented on the same endomicroscope with no hardware modifications, showed a more uniform illumination density with about an 80-fold reduction in the peak illumination density. To underscore the benefit offered by the improved illumination uniformity, we conducted in vitro two-photon fluorescence imaging of cultured cells stained with a LIVE/DEAD viability assay using our home-built, fiber-optic, two-channel endomicroscopy system. Both the spiral and the Lissajous scans were implemented. Our experimental results showed that cells near the spiral scan center experienced obvious photodamage, whereas cells remained alive over the entire region under the Lissajous beam scanning, confirming the predicted advantage offered by the Lissajous scan over this spiral scan in an endomicroscopy setting.

The study of CD side to side error in line/space pattern caused by post-exposure bake effect

NASA Astrophysics Data System (ADS)

Huang, Jin; Guo, Eric; Ge, Haiming; Lu, Max; Wu, Yijun; Tian, Mingjing; Yan, Shichuan; Wang, Ran

2016-10-01

In semiconductor manufacturing, as the design rule has decreased, the ITRS roadmap requires crucial tighter critical dimension (CD) control. CD uniformity is one of the necessary parameters to assure good performance and reliable functionality of any integrated circuit (IC) [1] [2], and towards the advanced technology nodes, it is a challenge to control CD uniformity well. The study of corresponding CD Uniformity by tuning Post-Exposure bake (PEB) and develop process has some significant progress[3], but CD side to side error happening to some line/space pattern are still found in practical application, and the error has approached to over the uniformity tolerance. After details analysis, even though use several developer types, the CD side to side error has not been found significant relationship to the developing. In addition, it is impossible to correct the CD side to side error by electron beam correction as such error does not appear in all Line/Space pattern masks. In this paper the root cause of CD side to side error is analyzed and the PEB module process are optimized as a main factor for improvement of CD side to side error.

Regulation of the Deposition Morphology of Inkjet-Printed Crystalline Materials via Polydopamine Functional Coatings for Highly Uniform and Electrically Conductive Patterns.

PubMed

Liu, Liang; Ma, Siyuan; Pei, Yunheng; Xiong, Xiao; Sivakumar, Preeth; Singler, Timothy J

2016-08-24

We report a method to achieve highly uniform inkjet-printed silver nitrate (AgNO3) and a reactive silver precursor patterns on rigid and flexible substrates functionalized with polydopamine (PDA) coatings. The printed AgNO3 patterns on PDA-coated substrates (glass and polyethylene terephthalate (PET)) exhibit a narrow thickness distribution ranging between 0.9 and 1 μm in the line transverse direction and uniform deposition profiles in the line axial direction. The deposited reactive silver precursor patterns on PDA-functionalized substrates also show "dome-shaped" morphology without "edge-thickened" structure due to "coffee-stain" effect. We posit that the highly uniform functional ink deposits formed on PDA-coated substrates are attributable to the strong binding interaction between the abundant catecholamine moieties at the PDA surface and the metallic silver cations (Ag(+) or Ag(NH3)(2+)) in the solutal inks. During printing of the ink rivulet and solvent evaporation, the substrate-liquid ink (S-L) interface is enriched with the silver-based cations and a solidification at the S/L interface is induced. The preferential solidification initiated at the S-L interface is further verified by the in situ visualization of the dynamic solidification process during solvent evaporation, and results suggest an enhanced crystal nucleation and growth localized at the S-L interface on PDA functionalized substrates. This interfacial interaction mediates solute transport in the liquid phase, resulting in the controlled enrichment of solute at the S-L interface and mitigated solute precipitation in both the contact line region and the liquid ink-vapor (L-V) interface due to evaporation. This mediated transport contributes to the final uniform solid deposition for both types of ink systems. This technique provides a complementary strategy for achieving highly uniform inkjet-printed crystalline structures, and can serve as an innovative foundation for high-precision additive delivery of functional materials.

Growth pattern of the surface of fungus Aspergillus colony

NASA Astrophysics Data System (ADS)

Matsuura, Shu; Miyazima, Sasuke

1992-05-01

Aspergillus oryzae colonies were grown under various glucose concentrations, temperatures, and agar concentrations, and the effects on the pattern were investigated. Patterns of colony were found to vary from uniform to diffusion-limited aggregation type.

The Pattern of Road Traffic Crashes in South East Iran

PubMed Central

Rad, Mahdieh; Martiniuk, Alexandra LC.; Ansari-Moghaddam, Alireza; Mohammadi, Mahdi; Rashedi, Fariborz; Ghasemi, Ardavan

2016-01-01

Background: In the present study, the epidemiologic aspects of road traffic crashes in South East of Iran are described. Methods: This cross-sectional study included the profile of 2398 motor vehicle crashes recorded in the police office in one Year in South East of Iran. Data collected included: demographics, the type of crash, type of involved vehicle, location of crash and factors contributing to the crash. Descriptive statistics were used for data analysis. Results: Collisions with other vehicles or objects contributed the highest proportion (62.4%) of motor vehicle crashes. Human factors including careless driving, violating traffic laws, speeding, and sleep deprivation/fatigue were the most important causal factors accounting for 90% of road crashes. Data shows that 41% of drivers were not using a seat belt at the time of crash. One- third of the crashes resulted in injury (25%) or death (5%). Conclusions: Reckless driving such as speeding and violation of traffic laws are major risk factors for crashes in the South East of Iran. This highlights the need for education along with traffic law enforcement to reduce motor vehicle crashes in future. PMID:27157159

The Pattern of Road Traffic Crashes in South East Iran.

PubMed

Rad, Mahdieh; Martiniuk, Alexandra Lc; Ansari-Moghaddam, Alireza; Mohammadi, Mahdi; Rashedi, Fariborz; Ghasemi, Ardavan

2016-09-01

In the present study, the epidemiologic aspects of road traffic crashes in South East of Iran are described. This cross-sectional study included the profile of 2398 motor vehicle crashes recorded in the police office in one Year in South East of Iran. Data collected included: demographics, the type of crash, type of involved vehicle, location of crash and factors contributing to the crash. Descriptive statistics were used for data analysis. Collisions with other vehicles or objects contributed the highest proportion (62.4%) of motor vehicle crashes. Human factors including careless driving, violating traffic laws, speeding, and sleep deprivation/fatigue were the most important causal factors accounting for 90% of road crashes. Data shows that 41% of drivers were not using a seat belt at the time of crash. One- third of the crashes resulted in injury (25%) or death (5%). Reckless driving such as speeding and violation of traffic laws are major risk factors for crashes in the South East of Iran. This highlights the need for education along with traffic law enforcement to reduce motor vehicle crashes in future.

Pattern and presentation of spine trauma in Gwagwalada-Abuja, Nigeria.

PubMed

Kawu, A A

2012-01-01

The objective was to demonstrate the correlations and effects of age, gender, and cause of accident on the type of vertebral fracture as well as on the likelihood to sustain neurological deficit following trauma in Nigeria. Spinal column injury is a well-documented problem but literature has been mute on this problem in Nigeria unlike the many papers on spinal cord injury. A retrospective review of spinal cord injured (SCI) patients was performed. Age, sex, cause and level of injury, fracture pattern and distribution, and neurologic presentation of SCI patients from 1997 to 2007 were studied from case notes. There were 202 patients with male preponderance and a mean age of 38.9 ± 11.4 years over the 11-year period. The most common cause of spine injury was road traffic injury (79.7%). Cervical spine injury (10.4%) accounted for the highest number of cases with complete neurologic deficit. The majority of patients, 119 (58.9%) sustained a type A fracture, 37 (18.3%) a type B fracture, and 41(20.3%) patients experienced a type C fracture. All patients had neurologic deficits. Age (P=0.032) and road traffic injury (P=0.029) were independently associated with type of fracture after multivariate analysis. Age (P=0.038), road traffic injury (P=0.027), and cervical spine fracture (P=0.009) were also independently associated with neurologic deficit. These data showed the correlation between trauma mechanism and the type of fracture seen, and also the type of fracture and the incidence of neurologic deficit. The predictors of fracture types are age and road traffic injury while age, road traffic injury, and cervical spine fractures predict neurologic deficit.

An ultra low-power and traffic-adaptive medium access control protocol for wireless body area network.

PubMed

Ullah, Sana; Kwak, Kyung Sup

2012-06-01

Wireless Body Area Network (WBAN) consists of low-power, miniaturized, and autonomous wireless sensor nodes that enable physicians to remotely monitor vital signs of patients and provide real-time feedback with medical diagnosis and consultations. It is the most reliable and cheaper way to take care of patients suffering from chronic diseases such as asthma, diabetes and cardiovascular diseases. Some of the most important attributes of WBAN is low-power consumption and delay. This can be achieved by introducing flexible duty cycling techniques on the energy constraint sensor nodes. Stated otherwise, low duty cycle nodes should not receive frequent synchronization and control packets if they have no data to send/receive. In this paper, we introduce a Traffic-adaptive MAC protocol (TaMAC) by taking into account the traffic information of the sensor nodes. The protocol dynamically adjusts the duty cycle of the sensor nodes according to their traffic-patterns, thus solving the idle listening and overhearing problems. The traffic-patterns of all sensor nodes are organized and maintained by the coordinator. The TaMAC protocol is supported by a wakeup radio that is used to accommodate emergency and on-demand events in a reliable manner. The wakeup radio uses a separate control channel along with the data channel and therefore it has considerably low power consumption requirements. Analytical expressions are derived to analyze and compare the performance of the TaMAC protocol with the well-known beacon-enabled IEEE 802.15.4 MAC, WiseMAC, and SMAC protocols. The analytical derivations are further validated by simulation results. It is shown that the TaMAC protocol outperforms all other protocols in terms of power consumption and delay.

An evaluation of marine traffic on the Chinese white dolphins

NASA Astrophysics Data System (ADS)

Lee, C.

2016-12-01

The proposed third runway reclamation project of Hong Kong airport will soon impact the surrounding population of Chinese white dolphins. According to the World Wide Fund for Nature (WWF), the size of the reclamation will be 650 hectares of land located to the north of the current airport platform. All of the necessary works will be conducted via the surrounding marine areas. During the construction period the dredging and reclamation activities will increase the risk of dolphins colliding with this extra marine traffic especially since this construction site is less than one kilometre away from the dolphin marine park of Sha Chau & Lung Kwu Chau. Furthermore, after the construction of the third runway, there will be a re-routing of Skypier Ferries and other high speed boats through this area. The dolphins will undoubtedly be disturbed. The increase in vessel traffic during the construction project will also generate sounds that may interfere with echolocation systems that dolphins rely on to navigate and fish. This further impact can be measured using underwater hydrophones that can record the boat noise as well as the dolphin clicks. The latter determines the presence or absence of dolphins. From this the impact of noise on dolphin populations can be determined by simply determining if the dolphins stay around during periods of high levels of underwater noise. The data presented is the result of several years of collection. A clear understanding of the conjunction of noises from the dolphins and marine traffic patterns for different times of the day will help determine the impact and offer the chance to change marine traffic patterns thus minimizing the adverse impact on the iconic Hong Kong white dolphins.

Classification of Automated Search Traffic

NASA Astrophysics Data System (ADS)

Buehrer, Greg; Stokes, Jack W.; Chellapilla, Kumar; Platt, John C.

As web search providers seek to improve both relevance and response times, they are challenged by the ever-increasing tax of automated search query traffic. Third party systems interact with search engines for a variety of reasons, such as monitoring a web site’s rank, augmenting online games, or possibly to maliciously alter click-through rates. In this paper, we investigate automated traffic (sometimes referred to as bot traffic) in the query stream of a large search engine provider. We define automated traffic as any search query not generated by a human in real time. We first provide examples of different categories of query logs generated by automated means. We then develop many different features that distinguish between queries generated by people searching for information, and those generated by automated processes. We categorize these features into two classes, either an interpretation of the physical model of human interactions, or as behavioral patterns of automated interactions. Using the these detection features, we next classify the query stream using multiple binary classifiers. In addition, a multiclass classifier is then developed to identify subclasses of both normal and automated traffic. An active learning algorithm is used to suggest which user sessions to label to improve the accuracy of the multiclass classifier, while also seeking to discover new classes of automated traffic. Performance analysis are then provided. Finally, the multiclass classifier is used to predict the subclass distribution for the search query stream.

Simple cellular automaton model for traffic breakdown, highway capacity, and synchronized flow

NASA Astrophysics Data System (ADS)

Kerner, Boris S.; Klenov, Sergey L.; Schreckenberg, Michael

2011-10-01

We present a simple cellular automaton (CA) model for two-lane roads explaining the physics of traffic breakdown, highway capacity, and synchronized flow. The model consists of the rules “acceleration,” “deceleration,” “randomization,” and “motion” of the Nagel-Schreckenberg CA model as well as “overacceleration through lane changing to the faster lane,” “comparison of vehicle gap with the synchronization gap,” and “speed adaptation within the synchronization gap” of Kerner's three-phase traffic theory. We show that these few rules of the CA model can appropriately simulate fundamental empirical features of traffic breakdown and highway capacity found in traffic data measured over years in different countries, like characteristics of synchronized flow, the existence of the spontaneous and induced breakdowns at the same bottleneck, and associated probabilistic features of traffic breakdown and highway capacity. Single-vehicle data derived in model simulations show that synchronized flow first occurs and then self-maintains due to a spatiotemporal competition between speed adaptation to a slower speed of the preceding vehicle and passing of this slower vehicle. We find that the application of simple dependences of randomization probability and synchronization gap on driving situation allows us to explain the physics of moving synchronized flow patterns and the pinch effect in synchronized flow as observed in real traffic data.

Modeling and simulation of the data communication network at the ASRM Facility

NASA Technical Reports Server (NTRS)

Nirgudkar, R. P.; Moorhead, R. J.; Smith, W. D.

1994-01-01

This paper describes the modeling and simulation of the communication network for the NASA Advanced Solid Rocket Motor (ASRM) facility under construction at Yellow Creek near Luka, Mississippi. Manufacturing, testing, and operations at the ASRM site will be performed in different buildings scattered over an 1800 acre site. These buildings are interconnected through a local area network (LAN), which will contain one logical Fiber Distributed Data Interface (FDDI) ring acting as a backbone for the whole complex. The network contains approximately 700 multi-vendor workstations, 22 multi-vendor workcells, and 3 VAX clusters interconnected via Ethernet and FDDI. The different devices produce appreciably different traffic patterns, each pattern will be highly variable, and some patterns will be very bursty. Most traffic is between the VAX clusters and the other devices. Comdisco's Block Oriented Network Simulator (BONeS) has been used for network simulation. The two primary evaluation parameters used to judge the expected network performance are throughput and delay.

Control techniques for an automated mixed traffic vehicle

NASA Technical Reports Server (NTRS)

Meisenholder, G. W.; Johnston, A. R.

1977-01-01

The paper describes an automated mixed traffic vehicle (AMTV), a driverless low-speed tram designed to operate in mixed pedestrian and vehicular traffic. The vehicle is a six-passenger electric tram equipped with sensing and control which permit it to function on existing streets in an automatic mode. The design includes established wire-following techniques for steering and near-IR headway sensors. A 7-mph cruise speed is reduced to 2 mph or a complete stop in response to sensor (or passenger) inputs. The AMTV performance is evaluated by operation on a loop route and by simulation. Some necessary improvements involving sensors, sensor pattern, use of an audible signal, and control lag are discussed. It is suggested that appropriate modifications will eliminate collision incidents.

Hydrodynamically induced oscillations and traffic dynamics in 1D microfludic networks

NASA Astrophysics Data System (ADS)

Bartolo, Denis; Jeanneret, Raphael

2011-03-01

We report on the traffic dynamics of particles driven through a minimal microfluidic network. Even in the minimal network consisting in a single loop, the traffic dynamics has proven to yield complex temporal patterns, including periodic, multi-periodic or chaotic sequences. This complex dynamics arises from the strongly nonlinear hydrodynamic interactions between the particles, that takes place at a junction. To better understand the consequences of this nontrivial coupling, we combined theoretical, numerical and experimental efforts and solved the 3-body problem in a 1D loop network. This apparently simple dynamical system revealed a rich and unexpected dynamics, including coherent spontaneous oscillations along closed orbits. Striking similarities between Hamiltonian systems and this driven dissipative system will be explained.

Performance of a Regional Aeronautical Telecommunications Network

NASA Technical Reports Server (NTRS)

Bretmersky, Steven C.; Ripamonti, Claudio; Konangi, Vijay K.; Kerczewski, Robert J.

2001-01-01

This paper reports the findings of the simulation of the ATN (Aeronautical Telecommunications Network) for three typical average-sized U.S. airports and their associated air traffic patterns. The models of the protocols were designed to achieve the same functionality and meet the ATN specifications. The focus of this project is on the subnetwork and routing aspects of the simulation. To maintain continuous communication between the aircrafts and the ground facilities, a model based on mobile IP is used. The results indicate that continuous communication is indeed possible. The network can support two applications of significance in the immediate future FTP and HTTP traffic. Results from this simulation prove the feasibility of development of the ATN concept for AC/ATM (Advanced Communications for Air Traffic Management).

Process For Patterning Dispenser-Cathode Surfaces

NASA Technical Reports Server (NTRS)

Garner, Charles E.; Deininger, William D.

1989-01-01

Several microfabrication techniques combined into process cutting slots 100 micrometer long and 1 to 5 micrometer wide into tungsten dispenser cathodes for traveling-wave tubes. Patterned photoresist serves as mask for etching underlying aluminum. Chemically-assisted ion-beam etching with chlorine removes exposed parts of aluminum layer. Etching with fluorine or chlorine trifluoride removes tungsten not masked by aluminum layer. Slots enable more-uniform low-work function coating dispensed to electron-emitting surface. Emission of electrons therefore becomes more uniform over cathode surface.

Ionization chamber dosimeter

DOEpatents

Renner, Tim R.; Nyman, Mark A.; Stradtner, Ronald

1991-01-01

A method for fabricating an ion chamber dosimeter collecting array of the type utilizing plural discrete elements formed on a uniform collecting surface which includes forming a thin insulating layer over an aperture in a frame having surfaces, forming a predetermined pattern of through holes in the layer, plating both surfaces of the layer and simultaneously tilting and rotating the frame for uniform plate-through of the holes between surfaces. Aligned masking and patterned etching of the surfaces provides interconnects between the through holes and copper leads provided to external circuitry.

Attenuated phase-shift mask (PSM) blanks for flat panel display

NASA Astrophysics Data System (ADS)

Kageyama, Kagehiro; Mochizuki, Satoru; Yamakawa, Hiroyuki; Uchida, Shigeru

2015-10-01

The fine pattern exposure techniques are required for Flat Panel display applications as smart phone, tablet PC recently. The attenuated phase shift masks (PSM) are being used for ArF and KrF photomask lithography technique for high end pattern Semiconductor applications. We developed CrOx based large size PSM blanks that has good uniformity on optical characteristics for FPD applications. We report the basic optical characteristics and uniformity, stability data of large sized CrOx PSM blanks.

30 CFR 46.11 - Site-specific hazard awareness training.

Code of Federal Regulations, 2011 CFR

2011-07-01

... environmental conditions, recognition and avoidance of hazards such as electrical and powered-haulage hazards, traffic patterns and control, and restricted areas; and warning and evacuation signals, evacuation and...

Road traffic fatalities in selected governorates of Iraq from 2010 to 2013: prospective surveillance.

PubMed

Leidman, Eva; Maliniak, Maret; Sultan, Abdul-Salam Saleh; Hassan, Ahmed; Hussain, Syed Jaffar; Bilukha, Oleg O

2016-01-01

The insurgency tactics that characterize modern warfare, such as suicide car bombs and roadside bombs, have the potential to significantly impact road traffic injuries in conflict affected-countries. As road traffic incidents are one of the top ten causes of death in Iraq, changes in incidence have important implications for the health system. We aimed to describe patterns of road traffic fatalities for all demographic groups and types of road users in Iraq during a period characterized by a resurgence in insurgency activity. Iraqi Ministry of Health routine prospective injury surveillance collects information on all fatal injuries in eight governorates of Iraq: Baghdad, Al-Anbar, Basrah, Erbil, Kerbala, Maysan, Ninevah, and Al-Sulaimaniya. From all injury fatalities documented at the coroner office, we analyzed only those attributed to road traffic that occurred between 1 January 2010 and 31 December 2013. Coroners ascertain information from physical examinations, police reports and family members. Analysis included 7,976 road traffic fatalities. Overall, 6,238 (78.2 %) fatalities were male and 2,272 (28.5 %) were children under 18 years of age. The highest numbers of road traffic fatalities were among males 15 to 34 years of age and children of both sexes under 5 years of age. 49.2 % of fatalities occurred among pedestrians. Among children and females, the majority of road traffic fatalities were pedestrians, 69.0 % and 56.6 %, respectively. Fatalities among motorcyclists (3.7 %) and bicyclists (0.4 %) were least common. Rates of road traffic fatalities ranged from 8.6 to 10.7 per 100,000 population. The injury surveillance system provides the first data from a conflict-affected country on road traffic fatalities disaggregated by type of road user. The highest numbers of fatalities were among children and young men. Nearly half of fatalities were pedestrians, a proportion nearly double that of any neighboring country. As insurgency activity increased in 2013, the number of road traffic fatalities declined.

A review of the effect of traffic and weather characteristics on road safety.

PubMed

Theofilatos, Athanasios; Yannis, George

2014-11-01

Taking into consideration the increasing availability of real-time traffic data and stimulated by the importance of proactive safety management, this paper attempts to provide a review of the effect of traffic and weather characteristics on road safety, identify the gaps and discuss the needs for further research. Despite the existence of generally mixed evidence on the effect of traffic parameters, a few patterns can be observed. For instance, traffic flow seems to have a non-linear relationship with accident rates, even though some studies suggest linear relationship with accidents. On the other hand, increased speed limits have found to have a straightforward positive relationship with accident occurrence. Regarding weather effects, the effect of precipitation is quite consistent and leads generally to increased accident frequency but does not seem to have a consistent effect on severity. The impact of other weather parameters on safety, such as visibility, wind speed and temperature is not found straightforward so far. The increasing use of real-time data not only makes easier to identify the safety impact of traffic and weather characteristics, but most importantly makes possible the identification of their combined effect. The more systematic use of these real-time data may address several of the research gaps identified in this research. Copyright © 2014 Elsevier Ltd. All rights reserved.

Is countershading camouflage robust to lighting change due to weather?

PubMed

Penacchio, Olivier; Lovell, P George; Harris, Julie M

2018-02-01

Countershading is a pattern of coloration thought to have evolved in order to implement camouflage. By adopting a pattern of coloration that makes the surface facing towards the sun darker and the surface facing away from the sun lighter, the overall amount of light reflected off an animal can be made more uniformly bright. Countershading could hence contribute to visual camouflage by increasing background matching or reducing cues to shape. However, the usefulness of countershading is constrained by a particular pattern delivering 'optimal' camouflage only for very specific lighting conditions. In this study, we test the robustness of countershading camouflage to lighting change due to weather, using human participants as a 'generic' predator. In a simulated three-dimensional environment, we constructed an array of simple leaf-shaped items and a single ellipsoidal target 'prey'. We set these items in two light environments: strongly directional 'sunny' and more diffuse 'cloudy'. The target object was given the optimal pattern of countershading for one of these two environment types or displayed a uniform pattern. By measuring detection time and accuracy, we explored whether and how target detection depended on the match between the pattern of coloration on the target object and scene lighting. Detection times were longest when the countershading was appropriate to the illumination; incorrectly camouflaged targets were detected with a similar pattern of speed and accuracy to uniformly coloured targets. We conclude that structural changes in light environment, such as caused by differences in weather, do change the effectiveness of countershading camouflage.

Control of Turing patterns and their usage as sensors, memory arrays, and logic gates

NASA Astrophysics Data System (ADS)

Muzika, František; Schreiber, Igor

2013-10-01

We study a model system of three diffusively coupled reaction cells arranged in a linear array that display Turing patterns with special focus on the case of equal coupling strength for all components. As a suitable model reaction we consider a two-variable core model of glycolysis. Using numerical continuation and bifurcation techniques we analyze the dependence of the system's steady states on varying rate coefficient of the recycling step while the coupling coefficients of the inhibitor and activator are fixed and set at the ratios 100:1, 1:1, and 4:5. We show that stable Turing patterns occur at all three ratios but, as expected, spontaneous transition from the spatially uniform steady state to the spatially nonuniform Turing patterns occurs only in the first case. The other two cases possess multiple Turing patterns, which are stabilized by secondary bifurcations and coexist with stable uniform periodic oscillations. For the 1:1 ratio we examine modular spatiotemporal perturbations, which allow for controllable switching between the uniform oscillations and various Turing patterns. Such modular perturbations are then used to construct chemical computing devices utilizing the multiple Turing patterns. By classifying various responses we propose: (a) a single-input resettable sensor capable of reading certain value of concentration, (b) two-input and three-input memory arrays capable of storing logic information, (c) three-input, three-output logic gates performing combinations of logical functions OR, XOR, AND, and NAND.

A comparison of safety benefits of pedestrian countdown signals with and without pushbuttons in Michigan.

PubMed

Boateng, Richard Atta; Kwigizile, Valerian; Oh, Jun-Seok

2018-04-11

This study evaluated the safety impacts of PCSs with and without pushbuttons based on pedestrian crashes and pedestrian injuries in Michigan. This study used ten years of intersection data: five years before PCSs were installed and five years after they were installed, along with a comparison group, to evaluate the crash impacts of PCSs: at 107 intersections the PCS had a pushbutton and at 96 it did not. At these intersections, and at their comparison sites (where no PCS was installed), crash data (from 2004-2016) were examined, along with traffic and geometric characteristics, population, education and poverty levels data. Intersections where PCSs with pushbuttons have been installed showed a 29 percent reduction in total pedestrian crashes and a 30 percent reduction in fatal/injury pedestrian crashes. Further, when considering only pedestrians age 65 and below, these respective reductions are 33 and 35 percent. Intersections with PCSs but without pushbuttons did not show any significant change in any type of pedestrian crash. Although the Manual of Uniform Traffic Control Devices (FHWA, 2009) requires the use of PCSs at new traffic signal installations, this study suggests a safety benefit of installing PCSs with pushbutton at signals where a PCS without a pushbutton is present.

Autonomic Arousals Related to Traffic Noise during Sleep

PubMed Central

Griefahn, Barbara; Bröde, Peter; Marks, Anke; Basner, Mathias

2008-01-01

Aim: To analyze the heart rate (HR) response to traffic noise during sleep and the influence of acoustic parameters, time of night, and momentary sleep stage on these responses. Participants: Twelve women and 12 men (19–28 years). Measurements and Results: The participants slept in the laboratory for 4 consecutive nights in each of 3 consecutive weeks and were exposed to aircraft, road, or rail traffic noise with weekly permutations. The 4 nights of each week consisted of a random sequence of a quiet night (32 dBA) and 3 nights during which aircraft, rail traffic, or road traffic noises occurred with maximum levels of 45–77 dBA. The polysomnogram and the electrocardiogram were recorded during all nights. In case of awakenings, the HR alterations consisted of monophasic elevations for >1 min, with mean maximum HR elevations of 30 bpm. Though obviously triggered by the noise events, the awakenings per se rather than the acoustical parameters determined the extent and pattern of the response. Without awakenings, HR responses were biphasic and consisted of initial accelerations with maximum HR elevations of about 9 bpm followed by decelerations below the baseline. These alterations were clearly influenced by the acoustic parameters (traffic mode, maximum level, rate of rise) as well as by the momentary sleep stage. Conclusions: Cardiac responses did not habituate to traffic noise within the night and may therefore play a key role in promoting traffic noise induced cardiovascular disease. If so, these consequences are more likely for responses accompanied by awakenings than for situations without awakenings. Citation: Griefahn B; Bröde P; Marks A; Basner M. Autonomic arousals related to traffic noise during sleep. SLEEP 2008;31(4):569-577. PMID:18457245

Forecasting mortality of road traffic injuries in China using seasonal autoregressive integrated moving average model.

PubMed

Zhang, Xujun; Pang, Yuanyuan; Cui, Mengjing; Stallones, Lorann; Xiang, Huiyun

2015-02-01

Road traffic injuries have become a major public health problem in China. This study aimed to develop statistical models for predicting road traffic deaths and to analyze seasonality of deaths in China. A seasonal autoregressive integrated moving average (SARIMA) model was used to fit the data from 2000 to 2011. Akaike Information Criterion, Bayesian Information Criterion, and mean absolute percentage error were used to evaluate the constructed models. Autocorrelation function and partial autocorrelation function of residuals and Ljung-Box test were used to compare the goodness-of-fit between the different models. The SARIMA model was used to forecast monthly road traffic deaths in 2012. The seasonal pattern of road traffic mortality data was statistically significant in China. SARIMA (1, 1, 1) (0, 1, 1)12 model was the best fitting model among various candidate models; the Akaike Information Criterion, Bayesian Information Criterion, and mean absolute percentage error were -483.679, -475.053, and 4.937, respectively. Goodness-of-fit testing showed nonautocorrelations in the residuals of the model (Ljung-Box test, Q = 4.86, P = .993). The fitted deaths using the SARIMA (1, 1, 1) (0, 1, 1)12 model for years 2000 to 2011 closely followed the observed number of road traffic deaths for the same years. The predicted and observed deaths were also very close for 2012. This study suggests that accurate forecasting of road traffic death incidence is possible using SARIMA model. The SARIMA model applied to historical road traffic deaths data could provide important evidence of burden of road traffic injuries in China. Copyright © 2015 Elsevier Inc. All rights reserved.

Road traffic and nearby grassland bird patterns in a suburbanizing landscape.

PubMed

Forman, Richard T T; Reineking, Bjorn; Hersperger, Anna M

2002-06-01

An extensive road system with rapidly increasing traffic produces diverse ecological effects that cover a large land area. Our objective was to evaluate the effect of roads with different traffic volumes on surrounding avian distributions, and its importance relative to other variables. Grassland bird data (5 years) for 84 open patches in an outer suburban/rural landscape near Boston were analyzed relative to: distance from roads with 3000-8000 to >30,000 vehicles/day; open-habitat patch size; area of quality microhabitat within a patch; adjacent land use; and distance to other open patches. Grassland bird presence and regular breeding correlated significantly with both distance from road and habitat patch size. Distance to nearest other open patch, irrespective of size, was not significant. Similarly, except for one species, adjacent land use, in this case built area, was not significant. A light traffic volume of 3000-8000 vehicles/day (local collector street here) had no significant effect on grassland bird distribution. For moderate traffic of 8000-15,000 (through street), there was no effect on bird presence although regular breeding was reduced for 400 m from a road. For heavier traffic of 15,000-30,000 (two-lane highway), both bird presence and breeding were decreased for 700 m. For a heavy traffic volume of > or =30,000 vehicles/day (multilane highway), bird presence and breeding were reduced for 1200 m from a road. The results suggest that avian studies and long-term surveys near busy roads may be strongly affected by traffic volume or changes in volume. We conclude that road ecology, especially the effects extending outward >100 m from roads with traffic, is a sine qua non for effective land-use and transportation policy.

Electronic structures of GeSi nanoislands grown on pit-patterned Si(001) substrate

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

Ye, Han, E-mail: Dabombyh@aliyun.com; Yu, Zhongyuan

2014-11-15

Patterning pit on Si(001) substrate prior to Ge deposition is an important approach to achieve GeSi nanoislands with high ordering and size uniformity. In present work, the electronic structures of realistic uncapped pyramid, dome, barn and cupola nanoislands grown in (105) pits are systematically investigated by solving Schrödinger equation for heavy-hole, which resorts to inhomogeneous strain distribution and nonlinear composition-dependent band parameters. Uniform, partitioned and equilibrium composition profile (CP) in nanoisland and inverted pyramid structure are simulated separately. We demonstrate the huge impact of composition profile on localization of heavy-hole: wave function of ground state is confined near pit facetsmore » for uniform CP, at bottom of nanoisland for partitioned CP and at top of nanoisland for equilibrium CP. Moreover, such localization is gradually compromised by the size effect as pit filling ratio or pit size decreases. The results pave the fundamental guideline of designing nanoislands on pit-patterned substrates for desired applications.« less

Performance improvements of binary diffractive structures via optimization of the photolithography and dry etch processes

NASA Astrophysics Data System (ADS)

Welch, Kevin; Leonard, Jerry; Jones, Richard D.

2010-08-01

Increasingly stringent requirements on the performance of diffractive optical elements (DOEs) used in wafer scanner illumination systems are driving continuous improvements in their associated manufacturing processes. Specifically, these processes are designed to improve the output pattern uniformity of off-axis illumination systems to minimize degradation in the ultimate imaging performance of a lithographic tool. In this paper, we discuss performance improvements in both photolithographic patterning and RIE etching of fused silica diffractive optical structures. In summary, optimized photolithographic processes were developed to increase critical dimension uniformity and featuresize linearity across the substrate. The photoresist film thickness was also optimized for integration with an improved etch process. This etch process was itself optimized for pattern transfer fidelity, sidewall profile (wall angle, trench bottom flatness), and across-wafer etch depth uniformity. Improvements observed with these processes on idealized test structures (for ease of analysis) led to their implementation in product flows, with comparable increases in performance and yield on customer designs.

Time-resolved characterization of primary and secondary particle emissions of a modern gasoline passenger car

NASA Astrophysics Data System (ADS)

Karjalainen, P.; Timonen, H.; Saukko, E.; Kuuluvainen, H.; Saarikoski, S.; Aakko-Saksa, P.; Murtonen, T.; Dal Maso, M.; Ahlberg, E.; Svenningsson, B.; Brune, W. H.; Hillamo, R.; Keskinen, J.; Rönkkö, T.

2015-11-01

Changes in traffic systems and vehicle emission reduction technologies significantly affect traffic-related emissions in urban areas. In many densely populated areas the amount of traffic is increasing, keeping the emission level high or even increasing. To understand the health effects of traffic related emissions, both primary and secondary particles that are formed in the atmosphere from gaseous exhaust emissions need to be characterized. In this study we used a comprehensive set of measurements to characterize both primary and secondary particulate emissions of a modern gasoline passenger car. Our aerosol particle study covers the whole process chain in emission formation, from the engine to the atmosphere, and takes into account also differences in driving patterns. We observed that in mass terms, the amount of secondary particles was 13 times higher than the amount of primary particles. The formation, composition, number, and mass of secondary particles was significantly affected by driving patterns and engine conditions. The highest gaseous and particulate emissions were observed at the beginning of the test cycle when the performance of the engine and the catalyst was below optimal. The key parameter for secondary particle formation was the amount of gaseous hydrocarbons in primary emissions; however, also the primary particle population had an influence. Thus, in order to enhance human health and wellbeing in urban areas, our study strongly indicates that in future legislation, special attention should be directed into the reduction of gaseous hydrocarbons.

Passenger car equivalents of becak bermotor at road segment in Medan

NASA Astrophysics Data System (ADS)

Surbakti, M. S.; Sembiring, I.

2018-02-01

The road traffic systems, travel patterns and other traffic characteristics are different for each country due to differences in the geometric patterns, available transport facilities for commuters, proportional and type of the vehicle itself and so on. In Indonesia, the standard of pce (Passenger Car Equivalent) value found on IHCM (Indonesian Highway Capacity Manual) published in 1997. IHCM stated that the value of pce for heavy vehicles and motorcycles are 1.3 and 0.5 respectively. On these day, regarding Medan as a third biggest city in Indonesia, there have been lot of changes with regarding to the composition of the vehicle, as well as variations of the type of the vehicle itself. Becak bermotor (motorized tricycles) is a vehicle which is widely available in the city of Medan. Data from Medan City Transportation Department stated that there are more than 20,000 motorized motorized tricycles vehicles operating in the city at these day. Pce value of these rickshaws will be calculated based on observations at road and intersections in Medan. The calculation result shows that the pce value of motorized rickshaw is more than 1. This value will make the calculations regarding the performance of the traffic can be performed more accurately.

An empirical assessment of driver motivation and emotional states in perceived safety margins under varied driving conditions.

PubMed

Zhang, Yu; Kaber, David B

2013-01-01

Motivation models in driving behaviour postulate that driver motives and emotional states dictate risk tolerance under various traffic conditions. The present study used time and driver performance-based payment systems to manipulate motivation and risk-taking behaviour. Ten participants drove to a predefined location in a simulated driving environment. Traffic patterns (density and velocity) were manipulated to cause driver behaviour adjustments due to the need to conform with the social norms of the roadway. The driving environment complexity was investigated as a mediating factor in risk tolerance. Results revealed the performance-based payment system to closely relate to risk-taking behaviour as compared with the time-based payment system. Drivers conformed with social norms associated with specific traffic patterns. Higher roadway complexity led to a more conservative safety margins and speeds. This research contributes to the further development of motivational models of driver behaviour. This study provides empirical justification for two motivation factors in driver risk-taking decisions, including compliance with social norm and emotions triggered by incentives. Environment complexity was identified as a mediating factor in motivational behaviour model. This study also recommended safety margin measures sensitive to changes in driver risk tolerance.

From trees to forest: relational complexity network and workload of air traffic controllers.

PubMed

Zhang, Jingyu; Yang, Jiazhong; Wu, Changxu

2015-01-01

In this paper, we propose a relational complexity (RC) network framework based on RC metric and network theory to model controllers' workload in conflict detection and resolution. We suggest that, at the sector level, air traffic showing a centralised network pattern can provide cognitive benefits in visual search and resolution decision which will in turn result in lower workload. We found that the network centralisation index can account for more variance in predicting perceived workload and task completion time in both a static conflict detection task (Study 1) and a dynamic one (Study 2) in addition to other aircraft-level and pair-level factors. This finding suggests that linear combination of aircraft-level or dyad-level information may not be adequate and the global-pattern-based index is necessary. Theoretical and practical implications of using this framework to improve future workload modelling and management are discussed. We propose a RC network framework to model the workload of air traffic controllers. The effect of network centralisation was examined in both a static conflict detection task and a dynamic one. Network centralisation was predictive of perceived workload and task completion time over and above other control variables.

12 CFR 303.42 - Filing procedures.

Code of Federal Regulations, 2014 CFR

2014-01-01

... contracts; (4) A statement on the impact of the proposal on the human environment, including, information on compliance with local zoning laws and regulations and the effect on traffic patterns for purposes of...

12 CFR 303.42 - Filing procedures.

Code of Federal Regulations, 2013 CFR

2013-01-01

... contracts; (4) A statement on the impact of the proposal on the human environment, including, information on compliance with local zoning laws and regulations and the effect on traffic patterns for purposes of...

12 CFR 303.42 - Filing procedures.

Code of Federal Regulations, 2010 CFR

2010-01-01

... contracts; (4) A statement on the impact of the proposal on the human environment, including, information on compliance with local zoning laws and regulations and the effect on traffic patterns for purposes of...

An electricity consumption model for electric vehicular flow

NASA Astrophysics Data System (ADS)

Xiao, Hong; Huang, Hai-Jun; Tang, Tie-Qiao

2016-09-01

In this paper, we apply the relationships between the macro and micro variables of traffic flow to develop an electricity consumption model for electric vehicular flow. We use the proposed model to study the quantitative relationships between the electricity consumption/total power and speed/density under uniform flow, and the electricity consumptions during the evolution processes of shock, rarefaction wave and small perturbation. The numerical results indicate that the proposed model can perfectly describe the electricity consumption for electric vehicular flow, which shows that the proposed model is reasonable.

Optical design of tunnel lighting with white light-emitting diodes.

PubMed

Tsai, Ming-Shiou; Lee, Xuan-Hao; Lo, Yi-Chien; Sun, Ching-Cherng

2014-10-10

This paper presents a tunnel lighting design consisting of a cluster light-emitting diode and a free-form lens. Most of the energy emitted from the proposed luminaire is transmitted onto the surface of the road in front of drivers, and the probability that that energy is emitted directly into drivers' eyes is low. Compared with traditional fluorescent lamps, the proposed luminaire, of which the optical utilization factor, optical efficiency, and uniformity are, respectively, 44%, 92.5%, and 0.72, exhibits favorable performance in energy saving, glare reduction, and traffic safety.

[Suitability of spatial pattern of camping sites in Langxiang Natural Reserve, Northeast Chi- na, based on GIS technology].

PubMed

Yuan, Wei; Zhang, Jie; Tan Ji-qiang; Zhou, Bo; Kang, Rui-cun; Wang, Ai-hong; Liu, Wei; Zhang, Lu

2015-09-01

It is an effective way for natural reserves to enhance self-supportive ability and realize sustainable development by developing ecotourism. Taking the experimental zone of Langxiang Natural Reserve in Heilongjiang Province as research object, the forest sub-compartment as research unit, and spatial pattern of environmental suitability of camping sites as research content, an evaluation index system taking natural environment, geographical security, infrastructure and traffic as project levels was built. Delphi and AHP methods were used to determine index weights. A spatial distribution map of camping environmental suitability in Langxiang Natural Reserve was drawn using the GIS spatial information processing technology based on "3S" measurement and the survey data. The results showed that the highest score for quantification of environmental suitability was 90, while the lowest score was 78, and the average value was 83.66 in the 1067 forest sub-compartments for test. The area of forest sub-compartments which were suitable for camping was 1094.44 hm2, being 12.2% of the experimental zone. The forest sub-compartments which had high environmental suitability in the research area were distributed uniformly and centralized with low degree of fragmentation. It was suggested that the contiguous forest sub-compartments with high scores of environmental suitability could be integrated for camping tourism. Due to the high level of environmental suitability for camping, the experimental zone of Langxiang Natural Reserve is suitable for developing camping tourism. Based on "3S" technology, the land use conditions of ecotourism environment of a natural reserve could be evaluated quickly and quantitatively by mathematical model.

The use of patterns to disguise environmental cues during an anticipatory judgment task.

PubMed

Causer, Joe; Williams, A Mark

2015-02-01

A number of novel manipulations to the design of playing uniforms were used to try to disguise the actions of penalty takers in soccer. Skilled and less-skilled soccer goalkeepers were required to anticipate penalty kick outcome while their opponent wore one of three different uniform designs that were intended to disguise the availability of potentially key information from the hip region. Variations of shapes/patterns were designed to conceal the actual alignment of the hips. Three occlusion points were used in the test film: -160 ms, -80 ms before, and at foot-ball contact. Skilled individuals reported higher accuracy scores than their less-skilled counterparts (p < .05). There were no performance decrements for the less-skilled group across the different uniform conditions (p > .05); however, the skilled group decreased their accuracy on the experimental conditions compared with the control (p < .05). Findings highlight the potential benefits of designing playing uniforms that facilitate disguise in sport.

An efficient shutter-less non-uniformity correction method for infrared focal plane arrays

NASA Astrophysics Data System (ADS)

Huang, Xiyan; Sui, Xiubao; Zhao, Yao

2017-02-01

The non-uniformity response in infrared focal plane array (IRFPA) detectors has a bad effect on images with fixed pattern noise. At present, it is common to use shutter to prevent from radiation of target and to update the parameters of non-uniformity correction in the infrared imaging system. The use of shutter causes "freezing" image. And inevitably, there exists the problems of the instability and reliability of system, power consumption, and concealment of infrared detection. In this paper, we present an efficient shutter-less non-uniformity correction (NUC) method for infrared focal plane arrays. The infrared imaging system can use the data gaining in thermostat to calculate the incident infrared radiation by shell real-timely. And the primary output of detector except the shell radiation can be corrected by the gain coefficient. This method has been tested in real infrared imaging system, reaching high correction level, reducing fixed pattern noise, adapting wide temperature range.

Simulation of air velocity in a vertical perforated air distributor

NASA Astrophysics Data System (ADS)

Ngu, T. N. W.; Chu, C. M.; Janaun, J. A.

2016-06-01

Perforated pipes are utilized to divide a fluid flow into several smaller streams. Uniform flow distribution requirement is of great concern in engineering applications because it has significant influence on the performance of fluidic devices. For industrial applications, it is crucial to provide a uniform velocity distribution through orifices. In this research, flow distribution patterns of a closed-end multiple outlet pipe standing vertically for air delivery in the horizontal direction was simulated. Computational Fluid Dynamics (CFD), a tool of research for enhancing and understanding design was used as the simulator and the drawing software SolidWorks was used for geometry setup. The main purpose of this work is to establish the influence of size of orifices, intervals between outlets, and the length of tube in order to attain uniformity of exit flows through a multi outlet perforated tube. However, due to the gravitational effect, the compactness of paddy increases gradually from top to bottom of dryer, uniform flow pattern was aimed for top orifices and larger flow for bottom orifices.

Long term sleep disturbance due to traffic noise

NASA Astrophysics Data System (ADS)

Vallet, M.; Gagneux, J.-M.; Blanchet, V.; Favre, B.; Labiale, G.

1983-09-01

This contribution to the evaluation of the effects of traffic noise on sleep disturbance is focused on the responses of people living near a main road. Experiments were carried out in the homes of subjects who had habitually been exposed to noise for periods of more than four years. The chronic changes in overall sleep patterns and the temporary sleep responses to particular noise events caused by traffic are demonstrated. Young people show mainly stage 3 and 4 deficits whilst older people show REM sleep deficits. The cardiac response to noise during sleep was also examined. These results highlight that both long term average and peak levels are important in assessing sleep disturbance. The threshold levels, measured inside the bedroom and above which sleep quality starts to become impaired, are 37 Leq(A) and 45 dB (A) Lp max , respectively. For the type of traffic studied these two levels are coherent and it is therefore possible that a single noise index, Leq(A), is sufficient to scale sleep disturbance.

Accurate Traffic Flow Prediction in Heterogeneous Vehicular Networks in an Intelligent Transport System Using a Supervised Non-Parametric Classifier.

PubMed

El-Sayed, Hesham; Sankar, Sharmi; Daraghmi, Yousef-Awwad; Tiwari, Prayag; Rattagan, Ekarat; Mohanty, Manoranjan; Puthal, Deepak; Prasad, Mukesh

2018-05-24

Heterogeneous vehicular networks (HETVNETs) evolve from vehicular ad hoc networks (VANETs), which allow vehicles to always be connected so as to obtain safety services within intelligent transportation systems (ITSs). The services and data provided by HETVNETs should be neither interrupted nor delayed. Therefore, Quality of Service (QoS) improvement of HETVNETs is one of the topics attracting the attention of researchers and the manufacturing community. Several methodologies and frameworks have been devised by researchers to address QoS-prediction service issues. In this paper, to improve QoS, we evaluate various traffic characteristics of HETVNETs and propose a new supervised learning model to capture knowledge on all possible traffic patterns. This model is a refinement of support vector machine (SVM) kernels with a radial basis function (RBF). The proposed model produces better results than SVMs, and outperforms other prediction methods used in a traffic context, as it has lower computational complexity and higher prediction accuracy.

Data Mining for Understanding and Improving Decision-making Affecting Ground Delay Programs

NASA Technical Reports Server (NTRS)

Kulkarni, Deepak; Wang, Yao; Sridhar, Banavar

2013-01-01

The continuous growth in the demand for air transportation results in an imbalance between airspace capacity and traffic demand. The airspace capacity of a region depends on the ability of the system to maintain safe separation between aircraft in the region. In addition to growing demand, the airspace capacity is severely limited by convective weather. During such conditions, traffic managers at the FAA's Air Traffic Control System Command Center (ATCSCC) and dispatchers at various Airlines' Operations Center (AOC) collaborate to mitigate the demand-capacity imbalance caused by weather. The end result is the implementation of a set of Traffic Flow Management (TFM) initiatives such as ground delay programs, reroute advisories, flow metering, and ground stops. Data Mining is the automated process of analyzing large sets of data and then extracting patterns in the data. Data mining tools are capable of predicting behaviors and future trends, allowing an organization to benefit from past experience in making knowledge-driven decisions.

Exact-Differential Large-Scale Traffic Simulation

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

Hanai, Masatoshi; Suzumura, Toyotaro; Theodoropoulos, Georgios

2015-01-01

Analyzing large-scale traffics by simulation needs repeating execution many times with various patterns of scenarios or parameters. Such repeating execution brings about big redundancy because the change from a prior scenario to a later scenario is very minor in most cases, for example, blocking only one of roads or changing the speed limit of several roads. In this paper, we propose a new redundancy reduction technique, called exact-differential simulation, which enables to simulate only changing scenarios in later execution while keeping exactly same results as in the case of whole simulation. The paper consists of two main efforts: (i) amore » key idea and algorithm of the exact-differential simulation, (ii) a method to build large-scale traffic simulation on the top of the exact-differential simulation. In experiments of Tokyo traffic simulation, the exact-differential simulation shows 7.26 times as much elapsed time improvement in average and 2.26 times improvement even in the worst case as the whole simulation.« less

Wild growing mushrooms for the Edible City? Cadmium and lead content in edible mushrooms harvested within the urban agglomeration of Berlin, Germany.

PubMed

Schlecht, Martin Thomas; Säumel, Ina

2015-09-01

Health effects by consuming urban garden products are discussed controversially due to high urban pollution loads. We sampled wild edible mushrooms of different habitats and commercial mushroom cultivars exposed to high traffic areas within Berlin, Germany. We determined the content of cadmium and lead in the fruiting bodies and analysed how the local setting shaped the concentration patterns. EU standards for cultivated mushrooms were exceeded by 86% of the wild mushroom samples for lead and by 54% for cadmium but not by mushroom cultures. We revealed significant differences in trace metal content depending on species, trophic status, habitat and local traffic burden. Higher overall traffic burden increased trace metal content in the biomass of wild mushrooms, whereas cultivated mushrooms exposed to inner city high traffic areas had significantly lower trace metal contents. Based on these we discuss the consequences for the consumption of mushrooms originating from urban areas. Copyright © 2015 Elsevier Ltd. All rights reserved.

Prediction of Particle Concentration using Traffic Emission Model

NASA Astrophysics Data System (ADS)

He, Hong-di; Lu, Jane Wei-zhen

2010-05-01

Vehicle emission is regarded as one of major sources of air pollution in urban area. Much attention has been addressed on it especially at traffic intersection. At intersection, vehicles frequently stop with idling engine during the red time and speed-up rapidly in the green time, which result in a high velocity fluctuation and produce extra pollutants to the surrounding air. To deeply understand such process, a semi-empirical model for predicting the changing effect of traffic flow patterns on particulate concentrations is proposed. The performance of the model is evaluated using the correlation coefficient and other parameters. From the results, the correlation coefficients in morning and afternoon data were found to be 0.86 an 0.73 respectively, which implies that the semi-empirical model for morning and afternoon data are 86% and 73% error free. Due to less affected by possible factors such as traffic volume and movement of pedestrian, the dispersion of the particulate matter in the morning is smaller and then contributes to higher performance than that in the afternoon.

Binocular rivalry from invisible patterns

PubMed Central

Zou, Jinyou; He, Sheng; Zhang, Peng

2016-01-01

Binocular rivalry arises when incompatible images are presented to the two eyes. If the two eyes’ conflicting features are invisible, leading to identical perceptual interpretations, does rivalry competition still occur? Here we investigated whether binocular rivalry can be induced from conflicting but invisible spatial patterns. A chromatic grating counterphase flickering at 30 Hz appeared uniform, but produced significant tilt aftereffect and orientation-selective adaptation. The invisible pattern also generated significant BOLD activities in the early visual cortex, with minimal response in the parietal and frontal cortical areas. Compared with perceptually matched uniform stimuli, a monocularly presented invisible chromatic grating enhanced the rivalry competition with a low-contrast visible grating presented to the other eye. Furthermore, switching from a uniform field to a perceptually matched invisible chromatic grating produced interocular suppression at approximately 200 ms after onset of the invisible grating. Experiments using briefly presented monocular probes revealed evidence for sustained rivalry competition between two invisible gratings during continuous dichoptic presentations. These findings indicate that even without visible interocular conflict, and with minimal engagement of frontoparietal cortex and consciousness related top-down feedback, perceptually identical patterns with invisible conflict features produce rivalry competition in the early visual cortex. PMID:27354535

Snow model analysis.

DOT National Transportation Integrated Search

2014-01-01

This study developed a new snow model and a database which warehouses geometric, weather and traffic : data on New Jersey highways. The complexity of the model development lies in considering variable road : width, different spreading/plowing pattern...

Modeling of Magnetoelastic Nanostructures with a Fully-coupled Mechanical-Micromagnetic Model and Its Applications

NASA Astrophysics Data System (ADS)

Liang, Cheng-Yen

Micromagnetic simulations of magnetoelastic nanostructures traditionally rely on either the Stoner-Wohlfarth model or the Landau-Lifshitz-Gilbert (LLG) model assuming uniform strain (and/or assuming uniform magnetization). While the uniform strain assumption is reasonable when modeling magnetoelastic thin films, this constant strain approach becomes increasingly inaccurate for smaller in-plane nanoscale structures. In this dissertation, a fully-coupled finite element micromagnetic method is developed. The method deals with the micromagnetics, elastodynamics, and piezoelectric effects. The dynamics of magnetization, non-uniform strain distribution, and electric fields are iteratively solved. This more sophisticated modeling technique is critical for guiding the design process of the nanoscale strain-mediated multiferroic elements such as those needed in multiferroic systems. In this dissertation, we will study magnetic property changes (e.g., hysteresis, coercive field, and spin states) due to strain effects in nanostructures. in addition, a multiferroic memory device is studied. The electric-field-driven magnetization switching by applying voltage on patterned electrodes simulation in a nickel memory device is shown in this work. The deterministic control law for the magnetization switching in a nanoring with electric field applied to the patterned electrodes is investigated. Using the patterned electrodes, we show that strain-induced anisotropy is able to be controlled, which changes the magnetization deterministically in a nano-ring.

Multiple LEDs luminous system in capsule endoscope

NASA Astrophysics Data System (ADS)

Mang, Ou-Yang; Huang, Shih-Wei; Lee, Hsin-Hung; Chen, Yung-Lin; Huang, Ko-Chih; Kuo, Yi-Ting

2007-02-01

Developing the luminous system in a capsule endoscope, it is difficult to obtain an uniform illumination[1] on the observed object because of several reasons: the light pattern of LED is sensitively depend on the driving current, location and projective angles; the optical path of LED light source is not parallel to the optical axis of the nearby imaging lenses; the strong reflection from the inner surface of the dome may saturate the CMOS sensors; the object plane of the observed intestine is not flat. Those reasons induce the over-blooming and deep-dark contrast in a picture and distort the original image strongly. The purpose of the article is to construct a photometric model to analyze the LED projection light pattern, and, furthermore, design a novel multiple LEDs luminous system for obtaining an uniform-brightness image. Several key parameters resulting as illumination uniformity has been taken under the model consideration and proven by experimental results. Those parameters include LED light pattern accuracy, choosing LED position relative to the imaging optical axis, LED numbers, arrangement, and the inner curvature of the dome. The novel structure improves the uniformity from 41% to 71% and reduces the light energy loss under 2%. The progress will help medical professionals to diagnose diseases and give treatment precisely based on the vivid image.

Mining spatiotemporal patterns of urban dwellers from taxi trajectory data

NASA Astrophysics Data System (ADS)

Mao, Feng; Ji, Minhe; Liu, Ting

2016-06-01

With the widespread adoption of locationaware technology, obtaining long-sequence, massive and high-accuracy spatiotemporal trajectory data of individuals has become increasingly popular in various geographic studies. Trajectory data of taxis, one of the most widely used inner-city travel modes, contain rich information about both road network traffic and travel behavior of passengers. Such data can be used to study the microscopic activity patterns of individuals as well as the macro system of urban spatial structures. This paper focuses on trajectories obtained from GPS-enabled taxis and their applications for mining urban commuting patterns. A novel approach is proposed to discover spatiotemporal patterns of household travel from the taxi trajectory dataset with a large number of point locations. The approach involves three critical steps: spatial clustering of taxi origin-destination (OD) based on urban traffic grids to discover potentially meaningful places, identifying threshold values from statistics of the OD clusters to extract urban jobs-housing structures, and visualization of analytic results to understand the spatial distribution and temporal trends of the revealed urban structures and implied household commuting behavior. A case study with a taxi trajectory dataset in Shanghai, China is presented to demonstrate and evaluate the proposed method.

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.

DDR process and materials for novel tone reverse technique

NASA Astrophysics Data System (ADS)

Shigaki, Shuhei; Shibayama, Wataru; Takeda, Satoshi; Tamura, Mamoru; Nakajima, Makoto; Sakamoto, Rikimaru

2018-03-01

We developed the novel process and material which can be created reverse-tone pattern without any collapse. The process was Dry Development Rinse (DDR) process, and the material used in this process was DDR material. DDR material was containing siloxane polymer which could be replaced the space area of the photo resist pattern. And finally, the reverse-tone pattern could be obtained by dry etching process without any pattern collapse issue. DDR process could be achieved fine line and space patterning below hp14nm without any pattern collapse by combination of PTD or NTD photo resist. DDR materials were demonstrated with latest coater track at imec. DDR process was fully automated and good CD uniformity was achieved after dry development. Detailed evaluation could be achieved with whole wafer such a study of CD uniformity (CDU). CDU of DDR pattern was compared to pre-pattern's CDU. Lower CDU was achieved and CDU healing was observed with special DDR material. By further evaluation, special DDR material showed relatively small E-slope compared to another DDR material. This small E-slope caused CDU improvement.

Mental health status, aggression, and poor driving distinguish traffic offenders from non-offenders but health status predicts driving behavior in both groups

PubMed Central

Abdoli, Nasrin; Farnia, Vahid; Delavar, Ali; Dortaj, Fariborz; Esmaeili, Alireza; Farrokhi, Noorali; Karami, Majid; Shakeri, Jalal; Holsboer-Trachsler, Edith; Brand, Serge

2015-01-01

Background In Iran, traffic accidents and deaths from traffic accidents are among the highest in the world, and generally, driver behavior rather than technical failures or environmental conditions are responsible for traffic accidents. In a previous study, we showed that among young Iranian male traffic offenders, poor mental health status, along with aggression, predicted poor driving behavior. The aims of the present study were twofold, to determine whether this pattern could be replicated among non-traffic offenders, and to compare the mental health status, aggression, and driving behavior of male traffic offenders and non-offenders. Methods A total of 850 male drivers (mean age =34.25 years, standard deviation =10.44) from Kermanshah (Iran) took part in the study. Of these, 443 were offenders (52.1%) and 407 (47.9%) were non-offenders with lowest driving penalty scores applying for attaining an international driving license. Participants completed a questionnaire booklet covering socio-demographic variables, traits of aggression, health status, and driving behavior. Results Compared to non-offenders, offenders reported higher aggression, poorer mental health status, and worse driving behavior. Among non-offenders, multiple regression indicated that poor health status, but not aggression, independently predicted poor driving behavior. Conclusion Compared to non-offenders, offenders reported higher aggression, poorer health status and driving behavior. Further, the predictive power of poorer mental health status, but not aggression, for driving behavior was replicated for male non-offenders. PMID:26300646

[A spatially explicit analysis of traffic accidents involving pedestrians and cyclists in Berlin].

PubMed

Lakes, Tobia

2017-12-01

In many German cities and counties, sustainable mobility concepts that strengthen pedestrian and cyclist traffic are promoted. From the perspectives of urban development, traffic planning and public healthcare, a spatially differentiated analysis of traffic accident data is decisive. 1) The identification of spatial and temporal patterns of the distribution of accidents involving cyclists and pedestrians, 2) the identification of hotspots and exploration of possible underlying causes and 3) the critical discussion of benefits and challenges of the results and the derivation of conclusions. Spatio-temporal distributions of data from accident statistics in Berlin involving pedestrians and cyclists from 2011 to 2015 were analysed with geographic information systems (GIS). While the total number of accidents remains relatively stable for pedestrian and cyclist accidents, the spatial distribution analysis shows, however, that there are significant spatial clusters (hotspots) of traffic accidents with a strong concentration in the inner city area. In a critical discussion, the benefits of geographic concepts are identified, such as spatially explicit health data (in this case traffic accident data), the importance of the integration of other data sources for the evaluation of the health impact of areas (traffic accident statistics of the police), and the possibilities and limitations of spatial-temporal data analysis (spatial point-density analyses) for the derivation of decision-supported recommendations and for the evaluation of policy measures of health prevention and of health-relevant urban development.

Complexity Management Using Metrics for Trajectory Flexibility Preservation and Constraint Minimization

NASA Technical Reports Server (NTRS)

Idris, Husni; Shen, Ni; Wing, David J.

2011-01-01

The growing demand for air travel is increasing the need for mitigating air traffic congestion and complexity problems, which are already at high levels. At the same time new surveillance, navigation, and communication technologies are enabling major transformations in the air traffic management system, including net-based information sharing and collaboration, performance-based access to airspace resources, and trajectory-based rather than clearance-based operations. The new system will feature different schemes for allocating tasks and responsibilities between the ground and airborne agents and between the human and automation, with potential capacity and cost benefits. Therefore, complexity management requires new metrics and methods that can support these new schemes. This paper presents metrics and methods for preserving trajectory flexibility that have been proposed to support a trajectory-based approach for complexity management by airborne or ground-based systems. It presents extensions to these metrics as well as to the initial research conducted to investigate the hypothesis that using these metrics to guide user and service provider actions will naturally mitigate traffic complexity. The analysis showed promising results in that: (1) Trajectory flexibility preservation mitigated traffic complexity as indicated by inducing self-organization in the traffic patterns and lowering traffic complexity indicators such as dynamic density and traffic entropy. (2)Trajectory flexibility preservation reduced the potential for secondary conflicts in separation assurance. (3) Trajectory flexibility metrics showed potential application to support user and service provider negotiations for minimizing the constraints imposed on trajectories without jeopardizing their objectives.

Same organization, same electronic health records (EHRs) system, different use: exploring the linkage between practice member communication patterns and EHR use patterns in an ambulatory care setting

PubMed Central

Leykum, Luci K; McDaniel, Reuben R

2011-01-01

Objective Despite efforts made by ambulatory care organizations to standardize the use of electronic health records (EHRs), practices often incorporate these systems into their work differently from each other. One potential factor contributing to these differences is within-practice communication patterns. The authors explore the linkage between within-practice communication patterns and practice-level EHR use patterns. Design Qualitative study of six practices operating within the same multi-specialty ambulatory care organization using the same EHR system. Semistructured interviews and direct observation were conducted with all physicians, nurses, medical assistants, practice managers, and non-clinical staff from each practice. Measurements An existing model of practice relationships was used to analyze communication patterns within the practices. Practice-level EHR use was defined and analyzed as the ways in which a practice uses an EHR as a collective or a group—including the degree of feature use, level of EHR-enabled communication, and frequency that EHR use changes in a practice. Interview and observation data were analyzed for themes. Based on these themes, within-practice communication patterns were categorized as fragmented or cohesive, and practice-level EHR use patterns were categorized as heterogeneous or homogeneous. Practices where EHR use was uniformly high across all users were further categorized as having standardized EHR use. Communication patterns and EHR use patterns were compared across the six practices. Results Within-practice communication patterns were associated with practice-level EHR use patterns. In practices where communication patterns were fragmented, EHR use was heterogeneous. In practices where communication patterns were cohesive, EHR use was homogeneous. Additional analysis revealed that practices that had achieved standardized EHR use (uniformly high EHR use across all users) exhibited high levels of mindfulness and respectful interaction, whereas practices that were furthest from achieving standardized EHR use exhibited low levels of mindfulness and respectful interaction. Conclusion Within-practice communication patterns provide a unique perspective for exploring the issue of standardization in EHR use. A major fallacy of setting homogeneous EHR use as the goal for practice-level EHR use is that practices with uniformly low EHR use could be considered successful. Achieving uniformly high EHR use across all users in a practice is more consistent with the goals of current EHR adoption and use efforts. It was found that some communication patterns among practice members may enable more standardized EHR use than others. Understanding the linkage between communication patterns and EHR use can inform understanding of the human element in EHR use and may provide key lessons for the implementation of EHRs and other health information technologies. PMID:21846780

Same organization, same electronic health records (EHRs) system, different use: exploring the linkage between practice member communication patterns and EHR use patterns in an ambulatory care setting.

PubMed

Lanham, Holly Jordan; Leykum, Luci K; McDaniel, Reuben R

2012-01-01

Despite efforts made by ambulatory care organizations to standardize the use of electronic health records (EHRs), practices often incorporate these systems into their work differently from each other. One potential factor contributing to these differences is within-practice communication patterns. The authors explore the linkage between within-practice communication patterns and practice-level EHR use patterns. Qualitative study of six practices operating within the same multi-specialty ambulatory care organization using the same EHR system. Semistructured interviews and direct observation were conducted with all physicians, nurses, medical assistants, practice managers, and non-clinical staff from each practice. An existing model of practice relationships was used to analyze communication patterns within the practices. Practice-level EHR use was defined and analyzed as the ways in which a practice uses an EHR as a collective or a group-including the degree of feature use, level of EHR-enabled communication, and frequency that EHR use changes in a practice. Interview and observation data were analyzed for themes. Based on these themes, within-practice communication patterns were categorized as fragmented or cohesive, and practice-level EHR use patterns were categorized as heterogeneous or homogeneous. Practices where EHR use was uniformly high across all users were further categorized as having standardized EHR use. Communication patterns and EHR use patterns were compared across the six practices. Within-practice communication patterns were associated with practice-level EHR use patterns. In practices where communication patterns were fragmented, EHR use was heterogeneous. In practices where communication patterns were cohesive, EHR use was homogeneous. Additional analysis revealed that practices that had achieved standardized EHR use (uniformly high EHR use across all users) exhibited high levels of mindfulness and respectful interaction, whereas practices that were furthest from achieving standardized EHR use exhibited low levels of mindfulness and respectful interaction. Within-practice communication patterns provide a unique perspective for exploring the issue of standardization in EHR use. A major fallacy of setting homogeneous EHR use as the goal for practice-level EHR use is that practices with uniformly low EHR use could be considered successful. Achieving uniformly high EHR use across all users in a practice is more consistent with the goals of current EHR adoption and use efforts. It was found that some communication patterns among practice members may enable more standardized EHR use than others. Understanding the linkage between communication patterns and EHR use can inform understanding of the human element in EHR use and may provide key lessons for the implementation of EHRs and other health information technologies.

Space evolution model and empirical analysis of an urban public transport network

NASA Astrophysics Data System (ADS)

Sui, Yi; Shao, Feng-jing; Sun, Ren-cheng; Li, Shu-jing

2012-07-01

This study explores the space evolution of an urban public transport network, using empirical evidence and a simulation model validated on that data. Public transport patterns primarily depend on traffic spatial-distribution, demands of passengers and expected utility of investors. Evolution is an iterative process of satisfying the needs of passengers and investors based on a given traffic spatial-distribution. The temporal change of urban public transport network is evaluated both using topological measures and spatial ones. The simulation model is validated using empirical data from nine big cities in China. Statistical analyses on topological and spatial attributes suggest that an evolution network with traffic demands characterized by power-law numerical values which distribute in a mode of concentric circles tallies well with these nine cities.

Improved high power/high frequency inductor

NASA Technical Reports Server (NTRS)

Mclyman, W. T. (Inventor)

1990-01-01

A toroidal core is mounted on an alignment disc having uniformly distributed circumferential notches or holes therein. Wire is then wound about the toroidal core in a uniform pattern defined by the notches or holes. Prior to winding, the wire may be placed within shrink tubing. The shrink tubing is then wound about the alignment disc and core and then heat-shrunk to positively retain the wire in the uniform position on the toroidal core.

Air pollution and survival within the Washington University-EPRI veterans cohort: risks based on modeled estimates of ambient levels of hazardous and criteria air pollutants.

PubMed

Lipfert, Frederick W; Wyzga, Ronald E; Baty, Jack D; Miller, J Philip

2009-04-01

For this paper, we considered relationships between mortality, vehicular traffic density, and ambient levels of 12 hazardous air pollutants, elemental carbon (EC), oxides of nitrogen (NOx), sulfur dioxide (SO2), and sulfate (SO4(2-)). These pollutant species were selected as markers for specific types of emission sources, including vehicular traffic, coal combustion, smelters, and metal-working industries. Pollutant exposures were estimated using emissions inventories and atmospheric dispersion models. We analyzed associations between county ambient levels of these pollutants and survival patterns among approximately 70,000 U.S. male veterans by mortality period (1976-2001 and subsets), type of exposure model, and traffic density level. We found significant associations between all-cause mortality and traffic-related air quality indicators and with traffic density per se, with stronger associations for benzene, formaldehyde, diesel particulate, NOx, and EC. The maximum effect on mortality for all cohort subjects during the 26-yr follow-up period is approximately 10%, but most of the pollution-related deaths in this cohort occurred in the higher-traffic counties, where excess risks approach 20%. However, mortality associations with diesel particulates are similar in high- and low-traffic counties. Sensitivity analyses show risks decreasing slightly over time and minor differences between linear and logarithmic exposure models. Two-pollutant models show stronger risks associated with specific traffic-related pollutants than with traffic density per se, although traffic density retains statistical significance in most cases. We conclude that tailpipe emissions of both gases and particles are among the most significant and robust predictors of mortality in this cohort and that most of those associations have weakened over time. However, we have not evaluated possible contributions from road dust or traffic noise. Stratification by traffic density level suggests the presence of response thresholds, especially for gaseous pollutants. Because of their wider distributions of estimated exposures, risk estimates based on emissions and atmospheric dispersion models tend to be more precise than those based on local ambient measurements.

Temporal patterns in road crossing behaviour in roe deer (Capreolus capreolus) at sites with wildlife warning reflectors

PubMed Central

Kämmerle, Jim-Lino; Kröschel, Max; Hagen, Robert; Storch, Ilse; Suchant, Rudi

2017-01-01

Every year, there are millions of documented vehicle collisions involving cervids across Europe and North America. While temporal patterns in collision occurrence are relatively well described, few studies have targeted deer behaviour as a critical component of collision prevention. In this study, we investigated weekly and daily patterns in road crossing behaviour in roe deer. Using road crossing events and movement data obtained from GPS telemetry, we employed mixed-effect models to explain frequency and timing of crossings at five road segments by a number of predictors including traffic volume, deer movement activity and the presence of wildlife warning reflectors. We analysed 13,689 road crossing events by 32 study animals. Individual variation in crossing frequency was high but daily patterns in crossing events were highly consistent among animals. Variation in the intensity of movement activity on a daily and seasonal scale was the main driver of road crossing behaviour. The seasonal variation in crossing frequency reflected differences in movement activity throughout the reproductive cycle, while daily variation in the probability to cross exhibited a clear nocturnal emphasis and reflected crepuscular activity peaks. The frequency of road crossings increased as a function of road density in the home-range, while traffic volume only exerted marginal effects. Movement activity of roe deer in our study coincided with commuter traffic mainly in the early morning and late afternoon during winter and during periods of high spatial activity such as the rut. Both timing and frequency of crossing events remained unchanged in the presence of reflectors. Our results emphasise the importance of behavioural studies for understanding roe deer vehicle-collision patterns and thus provide important information for collision prevention. We suggest that mitigation of collision risk should focus on strategic seasonal measures and animal warning systems targeting drivers. PMID:28953951

Inside the Mechanics of Network Development: How Competition and Strategy Reorganize European Air Traffic

NASA Technical Reports Server (NTRS)

Huber, Hans

2006-01-01

Air transport forms complex networks that can be measured in order to understand its structural characteristics and functional properties. Recent models for network growth (i.e., preferential attachment, etc.) remain stochastic and do not seek to understand other network-specific mechanisms that may account for their development in a more microscopic way. Air traffic is made up of many constituent airlines that are either privately or publicly owned and that operate their own networks. They follow more or less similar business policies each. The way these airline networks organize among themselves into distinct traffic distributions reveals complex interaction among them, which in turn can be aggregated into larger (macro-) traffic distributions. Our approach allows for a more deterministic methodology that will assess the impact of airline strategies on the distinct distributions for air traffic, particularly inside Europe. One key question this paper is seeking to answer is whether there are distinct patterns of preferential attachment for given classes of airline networks to distinct types of European airports. Conclusions about the advancing degree of concentration in this industry and the airline operators that accelerate this process can be drawn.

Urban air quality, meteorology and traffic linkages: Evidence from a sixteen-day particulate matter pollution event in December 2015, Beijing.

PubMed

Hu, Dongmei; Wu, Jianping; Tian, Kun; Liao, Lyuchao; Xu, Ming; Du, Yiman

2017-09-01

A heavy 16-day pollution episode occurred in Beijing from December 19, 2015 to January 3, 2016. The mean daily AQI and PM 2.5 were 240.44 and 203.6μg/m 3 . We analyzed the spatiotemporal characteristics of air pollutants, meteorology and road space speed during this period, then extended to reveal the combined effects of traffic restrictions and meteorology on urban air quality with observational data and a multivariate mutual information model. Results of spatiotemporal analysis showed that five pollution stages were identified with remarkable variation patterns based on evolution of PM 2.5 concentration and weather conditions. Southern sites (DX, YDM and DS) experienced heavier pollution than northern ones (DL, CP and WL). Stage P2 exhibited combined functions of meteorology and traffic restrictions which were delayed peak-clipping effects on PM 2.5 . Mutual information values of Air quality-Traffic-Meteorology (ATM-MI) revealed that additive functions of traffic restrictions, suitable relative humidity and temperature were more effective on the removal of fine particles and CO than NO 2 . Copyright © 2017. Published by Elsevier B.V.

Influence of approaching tram on behaviour of pedestrians in signalised crosswalks in Poland.

PubMed

Kruszyna, Maciej; Rychlewski, Jeremi

2013-06-01

Research done in two Polish cities has uncovered an influence of an approaching tram on pedestrian behaviour. The measurements were done by counting pedestrians waiting for a green signal, crossing on red signal safely, or crossing on red signal taking a risk of being hit by a car, differentiating between pedestrians attempting to board a public transport vehicle and other pedestrians. It was expected, that pedestrian behaviour might be influenced by traffic control predictability, therefore two cities were chosen for the task: Wrocław with fixed time traffic control and Poznań with a majority of traffic responsive traffic signals. Data from the measurements was compared in order to find behaviour patterns - the comparison led to a conclusion, that an attempt to get on board of an incoming public transport vehicle can be a major cause for pedestrians to violate a red signal, including an increase of unsafe behaviour. These pedestrians may provoke other pedestrians to cross on a red signal. On the other hand if traffic control guarantees boarding the public transport vehicle, passengers-to-be may be even more obedient than other pedestrians. Copyright © 2013 Elsevier Ltd. All rights reserved.

Driving risk and rural life: everyday and reconstructed realities.

PubMed

Rothe, J P; Elgert, L

2005-05-01

This article details the complex network of circumstances and meanings that influence rural people's driving behavior, and describes the manner in which some rural drivers' relevant social patterns support the everyday reality of driving and risk taking on rural roads. To fulfill the purpose of the study, 20 focus group interviews were conducted with 212 rural citizens in Alberta, Canada. The findings indicate that rural drivers routinely break traffic laws because: they do not perceive the harm in breaking laws, they believe that breaking laws is a natural thing to do, they negotiate the efficacy of laws according to their personal situations, and they believe in the maxim that the "ends justify the means. " It is common for rural drivers to break or "negotiate" traffic laws if it helps them in their work lives or in fulfillment of their immediate needs. They judge some traffic laws as unreasonable and question their effect on safety. Hence, they do not feel committed to universally honoring traffic laws. This information can be used to design intervention strategies for rural traffic safety that are relevant to rural drivers and thereby have optimal opportunity for success.

On implementation of DCTCP on three-tier and fat-tree data center network topologies.

PubMed

Zafar, Saima; Bashir, Abeer; Chaudhry, Shafique Ahmad

2016-01-01

A data center is a facility for housing computational and storage systems interconnected through a communication network called data center network (DCN). Due to a tremendous growth in the computational power, storage capacity and the number of inter-connected servers, the DCN faces challenges concerning efficiency, reliability and scalability. Although transmission control protocol (TCP) is a time-tested transport protocol in the Internet, DCN challenges such as inadequate buffer space in switches and bandwidth limitations have prompted the researchers to propose techniques to improve TCP performance or design new transport protocols for DCN. Data center TCP (DCTCP) emerge as one of the most promising solutions in this domain which employs the explicit congestion notification feature of TCP to enhance the TCP congestion control algorithm. While DCTCP has been analyzed for two-tier tree-based DCN topology for traffic between servers in the same rack which is common in cloud applications, it remains oblivious to the traffic patterns common in university and private enterprise networks which traverse the complete network interconnect spanning upper tier layers. We also recognize that DCTCP performance cannot remain unaffected by the underlying DCN architecture hence there is a need to test and compare DCTCP performance when implemented over diverse DCN architectures. Some of the most notable DCN architectures are the legacy three-tier, fat-tree, BCube, DCell, VL2, and CamCube. In this research, we simulate the two switch-centric DCN architectures; the widely deployed legacy three-tier architecture and the promising fat-tree architecture using network simulator and analyze the performance of DCTCP in terms of throughput and delay for realistic traffic patterns. We also examine how DCTCP prevents incast and outcast congestion when realistic DCN traffic patterns are employed in above mentioned topologies. Our results show that the underlying DCN architecture significantly impacts DCTCP performance. We find that DCTCP gives optimal performance in fat-tree topology and is most suitable for large networks.

Device Access Abstractions for Resilient Information Architecture Platform for Smart Grid

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

Dubey, Abhishek; Karsai, Gabor; Volgyesi, Peter

An open application platform distributes the intelligence and control capability to local endpoints (or nodes) reducing total network traffic, improving speed of local actions by avoiding latency, and improving reliability by reducing dependencies on numerous devices and communication interfaces. The platform must be multi-tasking and able to host multiple applications running simultaneously. Given such a system, the core functions of power grid control systems include grid state determination, low level control, fault intelligence and reconfiguration, outage intelligence, power quality measurement, remote asset monitoring, configuration management, power and energy management (including local distributed energy resources, such as wind, solar and energymore » storage) can be eventually distributed. However, making this move requires extensive regression testing of systems to prove out new technologies, such as phasor measurement units (PMU). Additionally, as the complexity of the systems increase with the inclusion of new functionality (especially at the distribution and consumer levels), hidden coupling issues becomes a challenge with possible N-way interactions known and not known by device and application developers. Therefore, it is very important to provide core abstractions that ensure uniform operational semantics across such interactions. Here in this paper, we describe the pattern for abstracting device interactions we have developed for the RIAPS platform in the context of a microgrid control application we have developed.« less

Device Access Abstractions for Resilient Information Architecture Platform for Smart Grid

DOE PAGES

Dubey, Abhishek; Karsai, Gabor; Volgyesi, Peter; ...

2018-06-12

An open application platform distributes the intelligence and control capability to local endpoints (or nodes) reducing total network traffic, improving speed of local actions by avoiding latency, and improving reliability by reducing dependencies on numerous devices and communication interfaces. The platform must be multi-tasking and able to host multiple applications running simultaneously. Given such a system, the core functions of power grid control systems include grid state determination, low level control, fault intelligence and reconfiguration, outage intelligence, power quality measurement, remote asset monitoring, configuration management, power and energy management (including local distributed energy resources, such as wind, solar and energymore » storage) can be eventually distributed. However, making this move requires extensive regression testing of systems to prove out new technologies, such as phasor measurement units (PMU). Additionally, as the complexity of the systems increase with the inclusion of new functionality (especially at the distribution and consumer levels), hidden coupling issues becomes a challenge with possible N-way interactions known and not known by device and application developers. Therefore, it is very important to provide core abstractions that ensure uniform operational semantics across such interactions. Here in this paper, we describe the pattern for abstracting device interactions we have developed for the RIAPS platform in the context of a microgrid control application we have developed.« less

Proceedings of the Public Workshop on Alternative Separation Concepts: Presentations, Discussions and Recommendations, held at Atlantic City Airport, New Jersey, January 7, 8 and 9, 1981.

DTIC Science & Technology

1981-06-01

going on with the MITRE Corporation taking a look at the methods of providing ATARS ser- vice to aircraft in the traffic pattern. And we’re using some...SRDS ... "DABS, BCAS and ATARS " 31 QUESTIONS AND ANSWERS . ... ........................ 37 SPEAKERS Andres Zellweger, FAA, OSEM ... 񕍜 Replacement...either EFR or normal IFR procedures is provided either by the DABS/ ATARS operating in a traffic separation rather than collision avoidance mode or by

LINEBACkER: Bio-inspired Data Reduction Toward Real Time Network Traffic Analysis

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

Teuton, Jeremy R.; Peterson, Elena S.; Nordwall, Douglas J.

Abstract—One essential component of resilient cyber applications is the ability to detect adversaries and protect systems with the same flexibility adversaries will use to achieve their goals. Current detection techniques do not enable this degree of flexibility because most existing applications are built using exact or regular-expression matching to libraries of rule sets. Further, network traffic defies traditional cyber security approaches that focus on limiting access based on the use of passwords and examination of lists of installed or downloaded programs. These approaches do not readily apply to network traffic occurring beyond the access control point, and when the datamore » in question are combined control and payload data of ever increasing speed and volume. Manual analysis of network traffic is not normally possible because of the magnitude of the data that is being exchanged and the length of time that this analysis takes. At the same time, using an exact matching scheme to identify malicious traffic in real time often fails because the lists against which such searches must operate grow too large. In this work, we introduce an alternative method for cyber network detection based on similarity-measuring algorithms for gene sequence analysis. These methods are ideal because they were designed to identify similar but nonidentical sequences. We demonstrate that our method is generally applicable to the problem of network traffic analysis by illustrating its use in two different areas both based on different attributes of network traffic. Our approach provides a logical framework for organizing large collections of network data, prioritizing traffic of interest to human analysts, and makes it possible to discover traffic signatures without the bias introduced by expert-directed signature generation. Pattern recognition on reduced representations of network traffic offers a fast, efficient, and more robust way to detect anomalies.« less

Air pollution and health risks due to vehicle traffic.

PubMed

Zhang, Kai; Batterman, Stuart

2013-04-15

Traffic congestion increases vehicle emissions and degrades ambient air quality, and recent studies have shown excess morbidity and mortality for drivers, commuters and individuals living near major roadways. Presently, our understanding of the air pollution impacts from congestion on roads is very limited. This study demonstrates an approach to characterize risks of traffic for on- and near-road populations. Simulation modeling was used to estimate on- and near-road NO2 concentrations and health risks for freeway and arterial scenarios attributable to traffic for different traffic volumes during rush hour periods. The modeling used emission factors from two different models (Comprehensive Modal Emissions Model and Motor Vehicle Emissions Factor Model version 6.2), an empirical traffic speed-volume relationship, the California Line Source Dispersion Model, an empirical NO2-NOx relationship, estimated travel time changes during congestion, and concentration-response relationships from the literature, which give emergency doctor visits, hospital admissions and mortality attributed to NO2 exposure. An incremental analysis, which expresses the change in health risks for small increases in traffic volume, showed non-linear effects. For a freeway, "U" shaped trends of incremental risks were predicted for on-road populations, and incremental risks are flat at low traffic volumes for near-road populations. For an arterial road, incremental risks increased sharply for both on- and near-road populations as traffic increased. These patterns result from changes in emission factors, the NO2-NOx relationship, the travel delay for the on-road population, and the extended duration of rush hour for the near-road population. This study suggests that health risks from congestion are potentially significant, and that additional traffic can significantly increase risks, depending on the type of road and other factors. Further, evaluations of risk associated with congestion must consider travel time, the duration of rush-hour, congestion-specific emission estimates, and uncertainties. Copyright © 2013 Elsevier B.V. All rights reserved.

Air pollution and health risks due to vehicle traffic

PubMed Central

Zhang, Kai; Batterman, Stuart

2014-01-01

Traffic congestion increases vehicle emissions and degrades ambient air quality, and recent studies have shown excess morbidity and mortality for drivers, commuters and individuals living near major roadways. Presently, our understanding of the air pollution impacts from congestion on roads is very limited. This study demonstrates an approach to characterize risks of traffic for on- and near-road populations. Simulation modeling was used to estimate on- and near-road NO2 concentrations and health risks for freeway and arterial scenarios attributable to traffic for different traffic volumes during rush hour periods. The modeling used emission factors from two different models (Comprehensive Modal Emissions Model and Motor Vehicle Emissions Factor Model version 6.2), an empirical traffic speed–volume relationship, the California Line Source Dispersion Model, an empirical NO2–NOx relationship, estimated travel time changes during congestion, and concentration–response relationships from the literature, which give emergency doctor visits, hospital admissions and mortality attributed to NO2 exposure. An incremental analysis, which expresses the change in health risks for small increases in traffic volume, showed non-linear effects. For a freeway, “U” shaped trends of incremental risks were predicted for on-road populations, and incremental risks are flat at low traffic volumes for near-road populations. For an arterial road, incremental risks increased sharply for both on- and near-road populations as traffic increased. These patterns result from changes in emission factors, the NO2–NOx relationship, the travel delay for the on-road population, and the extended duration of rush hour for the near-road population. This study suggests that health risks from congestion are potentially significant, and that additional traffic can significantly increase risks, depending on the type of road and other factors. Further, evaluations of risk associated with congestion must consider travel time, the duration of rush-hour, congestion-specific emission estimates, and uncertainties. PMID:23500830

Managing Time and Tasks.

ERIC Educational Resources Information Center

Handy, Alice Evans; Yucht, Alice H.

1993-01-01

Includes two articles that discuss time management and mail management strategies for librarians. Highlights include identifying personal work styles; planning and prioritizing; using calendars and computers; reexamining traffic patterns; delegating; and sorting and handling mail. (Contains eight references.) (LRW)

Is countershading camouflage robust to lighting change due to weather?

PubMed Central

2018-01-01

Countershading is a pattern of coloration thought to have evolved in order to implement camouflage. By adopting a pattern of coloration that makes the surface facing towards the sun darker and the surface facing away from the sun lighter, the overall amount of light reflected off an animal can be made more uniformly bright. Countershading could hence contribute to visual camouflage by increasing background matching or reducing cues to shape. However, the usefulness of countershading is constrained by a particular pattern delivering ‘optimal’ camouflage only for very specific lighting conditions. In this study, we test the robustness of countershading camouflage to lighting change due to weather, using human participants as a ‘generic’ predator. In a simulated three-dimensional environment, we constructed an array of simple leaf-shaped items and a single ellipsoidal target ‘prey’. We set these items in two light environments: strongly directional ‘sunny’ and more diffuse ‘cloudy’. The target object was given the optimal pattern of countershading for one of these two environment types or displayed a uniform pattern. By measuring detection time and accuracy, we explored whether and how target detection depended on the match between the pattern of coloration on the target object and scene lighting. Detection times were longest when the countershading was appropriate to the illumination; incorrectly camouflaged targets were detected with a similar pattern of speed and accuracy to uniformly coloured targets. We conclude that structural changes in light environment, such as caused by differences in weather, do change the effectiveness of countershading camouflage. PMID:29515822

Uniformity of plants regenerated from orange (Citrus sinensis Osb.) protoplasts.

PubMed

Kobayashi, S

1987-05-01

Using 25 plants (protoclones) regenerated from orange (Citrus sinensis Osb.) protoplasts, several characters, including leaf and flower morphology, leaf oil, isozyme patterns and chromosome number, were examined. No significant variations in each character were recorded among the protoclones. Uniformity observed among protoclones was identical to that of nucellar seedlings.

Is there any interaction between domestic radon exposure and air pollution from traffic in relation to childhood leukemia risk?

PubMed

Bräuner, Elvira Vaclavik; Andersen, Claus E; Andersen, Helle P; Gravesen, Peter; Lind, Morten; Ulbak, Kaare; Hertel, Ole; Schüz, Joachim; Raaschou-Nielsen, Ole

2010-11-01

In a recent population-based case-control study using 2,400 cases of childhood cancer, we found a statistically significant association between residential radon and acute lymphoblastic leukemia risk. Traffic exhaust in the air enhances the risk association between radon and childhood leukemia. We included 985 cases of childhood leukemia and 1,969 control children. We used validated models to calculate residential radon and street NO(x) concentrations for each home. Conditional logistic regression analyses were used to analyze the effect of radon on childhood leukemia risk within different strata of air pollution and traffic density. The relative risk for childhood leukemia in association with a 10(3) Bq/m(3)-years increase in radon was 1.77 (1.11, 2.82) among those exposed to high levels of NO(x) and 1.23 (0.79, 1.91) for those exposed to low levels of NO(x) (p(interaction,) 0.17). Analyses for different morphological subtypes of leukemia and within different strata of traffic density showed a non-significant pattern of stronger associations between radon and childhood leukemia within strata of higher traffic density at the street address. Air pollution from traffic may enhance the effect of radon on the risk of childhood leukemia. The observed tendency may also be attributed to chance.

Reflow process stabilization by chemical characteristics and process conditions

NASA Astrophysics Data System (ADS)

Kim, Myoung-Soo; Park, Jeong-Hyun; Kim, Hak-Joon; Kim, Il-Hyung; Jeon, Jae-Ha; Gil, Myung-Goon; Kim, Bong-Ho

2002-07-01

With the shrunken device rule below 130nm, the patterning of smaller contact hole with enough process margin is required for mass production. Therefore, shrinking technology using thermal reflow process has been applied for smaller contact hole formation. In this paper, we have investigated the effects of chemical characteristics such as molecular weight, blocking ratio of resin, cross-linker amount and solvent type with its composition to reflow process of resist and found the optimized chemical composition for reflow process applicable condition. And several process conditions like resist coating thickness and multi-step thermal reflow method have been also evaluated to stabilize the pattern profile and improve CD uniformity after reflow process. From the experiment results, it was confirmed that the effect of crosslinker in resist to reflow properties such as reflow temperature and reflow rate were very critical and it controlled the pattern profile during reflow processing. And also, it showed stable CD uniformity and improved resist properties for top loss, film shrinkage and etch selectivity. The application of lower coating thickness of resist induced symmetric pattern profile even at edge with wider process margin. The introduction of two-step baking method for reflow process showed uniform CD value, also. It is believed that the application of resist containing crosslinker and optimized process conditions for smaller contact hole patterning is necessary for the mass production with a design rule below 130nm.

Optimization of sampling pattern and the design of Fourier ptychographic illuminator.

PubMed

Guo, Kaikai; Dong, Siyuan; Nanda, Pariksheet; Zheng, Guoan

2015-03-09

Fourier ptychography (FP) is a recently developed imaging approach that facilitates high-resolution imaging beyond the cutoff frequency of the employed optics. In the original FP approach, a periodic LED array is used for sample illumination, and therefore, the scanning pattern is a uniform grid in the Fourier space. Such a uniform sampling scheme leads to 3 major problems for FP, namely: 1) it requires a large number of raw images, 2) it introduces the raster grid artefacts in the reconstruction process, and 3) it requires a high-dynamic-range detector. Here, we investigate scanning sequences and sampling patterns to optimize the FP approach. For most biological samples, signal energy is concentrated at low-frequency region, and as such, we can perform non-uniform Fourier sampling in FP by considering the signal structure. In contrast, conventional ptychography perform uniform sampling over the entire real space. To implement the non-uniform Fourier sampling scheme in FP, we have designed and built an illuminator using LEDs mounted on a 3D-printed plastic case. The advantages of this illuminator are threefold in that: 1) it reduces the number of image acquisitions by at least 50% (68 raw images versus 137 in the original FP setup), 2) it departs from the translational symmetry of sampling to solve the raster grid artifact problem, and 3) it reduces the dynamic range of the captured images 6 fold. The results reported in this paper significantly shortened acquisition time and improved quality of FP reconstructions. It may provide new insights for developing Fourier ptychographic imaging platforms and find important applications in digital pathology.

Method of constructing dished ion thruster grids to provide hole array spacing compensation

NASA Technical Reports Server (NTRS)

Banks, B. A. (Inventor)

1976-01-01

The center-to-center spacings of a photoresist pattern for an array of holes applied to a thin metal sheet are increased by uniformly stretching the thin metal sheet in all directions along the plane of the sheet. The uniform stretching is provided by securely clamping the periphery of the sheet and applying an annular force against the face of the sheet, within the periphery of the sheet and around the photoresist pattern. The technique is used in the construction of ion thruster grid units where the outer or downstream grid is subjected to uniform stretching prior to convex molding. The technique provides alignment of the holes of grid pairs so as to direct the ion beamlets in a direction parallel to the axis of the grid unit and thereby provide optimization of the available thrust.

Pattern of non-fatal injuries in road traffic crashes in a hilly area: A study from Shimla, North India.

PubMed

Mahajan, Narinder; Aggarwal, Meenu; Raina, Sunil; Verma, Lekh Raj; Mazta, Salig Ram; Gupta, B P

2013-07-01

What are the various injuries in road traffic crash cases? To study various non-fatal injuries in road traffic crash cases. Hospital based Descriptive study. The study population comprised of 401 consecutive cases of non- fatal injuries involved in road traffic crashes and reported at Indira Gandhi Medical College hospital, Shimla. 1(st) June 2005 to 31(st) May 2006. Demographic characteristics of the victims, pattern of injuries and hospital stay of the victims. Types of crashes, time, day and month of crashes, vehicles involved in crashes, use of protective gear etc. Percentages, Proportions. 73% of the injured victims were young between 20-49yrs, male to female ratio being 5.3:1. Employees (34.7%) and occupants of transport vehicles (45.9%) constituted the maximum number of the victims. Major injuries (fractures and abd. injuries) were reported in 53.4% of the victims and fractures of lower limb were the commonest of the injuries (26.3%). Use of seat-belt was found to be alarmingly low (14.3%) amongst the four- wheeler users and its non-use was found to be significantly associated with the major injuries. Helmet was used by 36 cases (66.7%) out of total of 54 users of motorized two-wheelers at the time of crash. Human error was the most reported cause of crash (82%) and the most common mode of crash was skidding and/rolling down (55%).23.1% of the drivers were reported to have consumed alcohol at the time of crash.

Traffic sign recognition based on a context-aware scale-invariant feature transform approach

NASA Astrophysics Data System (ADS)

Yuan, Xue; Hao, Xiaoli; Chen, Houjin; Wei, Xueye

2013-10-01

A new context-aware scale-invariant feature transform (CASIFT) approach is proposed, which is designed for the use in traffic sign recognition (TSR) systems. The following issues remain in previous works in which SIFT is used for matching or recognition: (1) SIFT is unable to provide color information; (2) SIFT only focuses on local features while ignoring the distribution of global shapes; (3) the template with the maximum number of matching points selected as the final result is instable, especially for images with simple patterns; and (4) SIFT is liable to result in errors when different images share the same local features. In order to resolve these problems, a new CASIFT approach is proposed. The contributions of the work are as follows: (1) color angular patterns are used to provide the color distinguishing information; (2) a CASIFT which effectively combines local and global information is proposed; and (3) a method for computing the similarity between two images is proposed, which focuses on the distribution of the matching points, rather than using the traditional SIFT approach of selecting the template with maximum number of matching points as the final result. The proposed approach is particularly effective in dealing with traffic signs which have rich colors and varied global shape distribution. Experiments are performed to validate the effectiveness of the proposed approach in TSR systems, and the experimental results are satisfying even for images containing traffic signs that have been rotated, damaged, altered in color, have undergone affine transformations, or images which were photographed under different weather or illumination conditions.

The School Office: An Overview.

ERIC Educational Resources Information Center

Hudson, Randy

2000-01-01

Presents an overview of the fundamental principles of school office design that remain constant despite changes in building technologies, and technological and spatial flexibility. Principles discussed include the school office and traffic patterns, security, and visitor reception requirements. (GR)

Wayfinding in Libraries.

ERIC Educational Resources Information Center

Beck, Susan Gilbert

1996-01-01

Discusses recommendations for designing or redesigning library buildings for easy navigability. Signage, maps, collection arrangements, and placement of emergency exits must take into account observed traffic patterns, spatial or objective orientations of individual patrons, and patrons with disabilities. Contains 63 references. (BEW)

Detection and enforcement of failure-to-yield in an emergency vehicle preemption system

NASA Technical Reports Server (NTRS)

Bachelder, Aaron (Inventor); Wickline, Richard (Inventor)

2007-01-01

An intersection controlled by an intersection controller receives trigger signals from on-coming emergency vehicles responding to an emergency call. The intersection controller initiates surveillance of the intersection via cameras installed at the intersection in response to a received trigger signal. The surveillance may begin immediately upon receipt of the trigger signal from an emergency vehicle, or may wait until the intersection controller determines that the signaling emergency vehicle is in the field of view of the cameras at the intersection. Portions of the captured images are tagged by the intersection controller based on tag signals transmitted by the vehicle or based on detected traffic patterns that indicate a potential traffic violation. The captured images are downloaded to a processing facility that analyzes the images and automatically issues citations for captured traffic violations.

Comparing Methods for Dynamic Airspace Configuration

NASA Technical Reports Server (NTRS)

Zelinski, Shannon; Lai, Chok Fung

2011-01-01

This paper compares airspace design solutions for dynamically reconfiguring airspace in response to nominal daily traffic volume fluctuation. Airspace designs from seven algorithmic methods and a representation of current day operations in Kansas City Center were simulated with two times today's demand traffic. A three-configuration scenario was used to represent current day operations. Algorithms used projected unimpeded flight tracks to design initial 24-hour plans to switch between three configurations at predetermined reconfiguration times. At each reconfiguration time, algorithms used updated projected flight tracks to update the subsequent planned configurations. Compared to the baseline, most airspace design methods reduced delay and increased reconfiguration complexity, with similar traffic pattern complexity results. Design updates enabled several methods to as much as half the delay from their original designs. Freeform design methods reduced delay and increased reconfiguration complexity the most.