Stability of car following with human memory effects and automatic headway compensation.

Science.gov (United States)

Sipahi, Rifat; Niculescu, Silviu-Iulian

2010-10-13

This paper addresses the study of some appropriate control strategies in order to guarantee the exponential stability of a class of deterministic microscopic car-following models including human drivers' memory effects and automated headway controllers. More precisely, the delayed action/decision of human drivers is represented using distributed delays with a gap and the considered automated controller is of proportional derivative type. The analysis is performed in both delay parameter and controller gain parameter spaces, and appropriate algorithms are proposed. Surprisingly, large delays and/or gains improve stability for the corresponding closed-loop schemes. Finally, some illustrative examples as well as various interpretations of the results complete the presentation.

Reducing travel delay by in-car advice on speed, headway and lane use based on downstream traffic flow conditions - a simulation study

NARCIS (Netherlands)

Schakel, W.J.; Klunder, G.; van Arem, B.; Harmsen, E.; Hagenzieker, M.P.

2012-01-01

A new advisory ADAS system is implemented in micro simulation to asses the effects on traffic flow as well as on safety. The system uses loop detector data from which situations may be recognized where advices are given to drivers in-car. Advice is given on speed, headway and lane use. Effectively

Critical Evaluation of the New Headway Advanced and the ILI Advanced Series: A Comparison of Curricular Components and CLT Objectives Based on ACTFL

OpenAIRE

Esmail Zare-Behtash; Hassan Banaruee

2017-01-01

The critical evaluation of systematic planning, development and review practices of instructional materials intend to improve the quality of teaching and learning. This study investigates the objectives of communicative language teaching and curricular components of two important textbooks which are widely studied in Iran: the New Headway Advanced Series (2015), the Iran Language Institute (ILI) Advanced1 (2008). The evaluation is done in terms of two prospects; firstly, the interpretation of...

The need for holding tracks at major intersections for synchronizing freight-train movements with fixed-headway passenger services; Wartegleisbedarf in Grossknoten fuer Synchronisation von Gueterverkehr mit vertaktetem Reiseverkehr

Energy Technology Data Exchange (ETDEWEB)

Mutschink, K. [DB Netz AG, Leipzig (Germany)

2005-05-01

Nearly all the big railway interesections have some facilities for passenger trains and others for freight trains. Most passenger trains today run according to fixed-headway timetables. Freight movements, on the other hand, are still basically need-driven with fluctuations in both timing and volumes. Handling both types of train as harmoniously as possible on shared lines calls for a combination of the meticulous planning of timetables and the correct dimensioning of the infrastructure. It is particularly in the vicinity of major intersections, where long-distance and local passenger trains (both with their fixed headways) converge within certain time windows, that approaching freight trains can only be effectively routed from their arrival lines to their departure lines if timing is properly synchronized. This may require the provision of a number of holding tracks for freight trains, and the essence of this article is how to compute that number using a procedure based on recognized scientific-management methods as applied to railways. This approach is centred on concepts such as certain 'no go' times for freight trains and the precise matching of train paths with the infrastructure. It does, however, take other parameters into account too, and these include the performance characteristics of each line (such as minimum headways), trains approaching ahead of their scheduled time and service constraints (such as ensuring connections and maintaining balanced intervals between passenger trains). The statistical appraisal, which is performed analytically, is designed to make sure that any results that are worked out are not slavishly dependent on the timetable, since (as mentioned above) freight movements in future will continue to be subject to fluctuations in volumes and timing. (orig.)

Critical Evaluation of the New Headway Advanced and the ILI Advanced Series: A Comparison of Curricular Components and CLT Objectives Based on ACTFL

Directory of Open Access Journals (Sweden)

Esmail Zare-Behtash

2017-07-01

Full Text Available The critical evaluation of systematic planning, development and review practices of instructional materials intend to improve the quality of teaching and learning. This study investigates the objectives of communicative language teaching and curricular components of two important textbooks which are widely studied in Iran: the New Headway Advanced Series (2015, the Iran Language Institute (ILI Advanced1 (2008. The evaluation is done in terms of two prospects; firstly, the interpretation of communicative language teaching objectives and secondly, curricular components of the books. To this aim, a checklist of 5 Cs standards and seven curricular components evaluation developed by American Council on the Teaching of Foreign Languages (ACTFL was employed. The evaluation reveals that the New Headway advanced series is more preferable and desirable than the ILI Advanced 1 due to the design and organization, authenticity, attractiveness, functionality, practicality and the other qualities mentioned above regarding communication, cultures, connection, comparison, and community in all aspects. The evaluation based on the seven curricular components- language systems, communication strategies, cultural knowledge, learning strategies, content from other subject areas, critical thinking skills, technology and the other features- indicates that the ILI textbook enjoys low standards and is not well developed in all components. The ILI textbook is highly reading and writing oriented and not appropriate for transactional and interactional learning purposes. This study acquaints language teachers and learners with the more desirable and cogent book.

Longer-term effects of ADAS use on speed and headway control in drivers diagnosed with Parkinson's disease.

Science.gov (United States)

Dotzauer, Mandy; Caljouw, Simone R; De Waard, Dick; Brouwer, Wiebo H

2015-01-01

An advanced driver assistance system (ADAS) provided information about speed limits, speed, speeding, and following distance. Information was presented to the participants by means of a head-up display. Effects of the information on speed and headway control were studied in a longer-term driving simulator study including 12 repeated measures spread out over 4 weeks. Nine healthy older drivers between the ages of 65 and 82 years and 9 drivers between the ages of 68 and 82 years diagnosed with Parkinson's disease (PD) participated in the study. Within the 4 weeks, groups completed 12 consecutive sessions (10 with ADAS and 2 without ADAS) in a driving simulator. Results indicate an effect of ADAS use on performance. Removing ADAS after short-term exposure led to deterioration of performance in all speed measures in the group of drivers diagnosed with PD. These results suggest that provision of traffic information was utilized by drivers diagnosed with PD in order to control their speed.

Traveling waves in an optimal velocity model of freeway traffic

Science.gov (United States)

Berg, Peter; Woods, Andrew

2001-03-01

Car-following models provide both a tool to describe traffic flow and algorithms for autonomous cruise control systems. Recently developed optimal velocity models contain a relaxation term that assigns a desirable speed to each headway and a response time over which drivers adjust to optimal velocity conditions. These models predict traffic breakdown phenomena analogous to real traffic instabilities. In order to deepen our understanding of these models, in this paper, we examine the transition from a linear stable stream of cars of one headway into a linear stable stream of a second headway. Numerical results of the governing equations identify a range of transition phenomena, including monotonic and oscillating travelling waves and a time- dependent dispersive adjustment wave. However, for certain conditions, we find that the adjustment takes the form of a nonlinear traveling wave from the upstream headway to a third, intermediate headway, followed by either another traveling wave or a dispersive wave further downstream matching the downstream headway. This intermediate value of the headway is selected such that the nonlinear traveling wave is the fastest stable traveling wave which is observed to develop in the numerical calculations. The development of these nonlinear waves, connecting linear stable flows of two different headways, is somewhat reminiscent of stop-start waves in congested flow on freeways. The different types of adjustments are classified in a phase diagram depending on the upstream and downstream headway and the response time of the model. The results have profound consequences for autonomous cruise control systems. For an autocade of both identical and different vehicles, the control system itself may trigger formations of nonlinear, steep wave transitions. Further information is available [Y. Sugiyama, Traffic and Granular Flow (World Scientific, Singapore, 1995), p. 137].

Planning the most suitable travel speed for high frequency railway lines

DEFF Research Database (Denmark)

Landex, Alex; Kaas, Anders H.

2005-01-01

the interlocking system. Based on the braking distance it is possible to calculate the minimum headway time, and thereby determine the buffer time when knowing the frequency. Hence the headway time can be divided into minimum headway time and buffer time. The buffer time is an indicator for the spare capacity......This paper presents a new method to calculate the most suitable travel speed for high frequency railway lines to achieve as much capacity as possible for congested railway lines. The method calculates the most suitable travel speed based on the braking distance and information about...

A new car-following model with two delays

International Nuclear Information System (INIS)

Yu, Lei; Shi, Zhong-ke; Li, Tong

2014-01-01

A new car-following model is proposed by taking into account two different time delays in sensing headway and velocity. The effect of time delays on the stability analysis is studied. The theoretical and numerical results show that traffic jams are suppressed efficiently when the difference between two time delays decreases and those can be described by the solution of the modified Korteweg–de Vries (mKdV) equation. Traffic flow is more stable with two delays in headway and velocity than in the case with only one delay in headway. The impact of local small disturbance to the system is also studied.

Ervaringen met Advanced Cruise Control (ACC) in een korte praktijkproef.

NARCIS (Netherlands)

Oei, H.-l.

2003-01-01

Experiences with Advanced Cruise Control in traffic; a limited experiment. Advanced Cruise Control (ACC) is an ordinary cruise control in which the desired speed is installed manually, but in which the headway time to the vehicle in front is also taken into account. If the headway time becomes less

Assessing crash risk considering vehicle interactions with trucks using point detector data.

Science.gov (United States)

Hyun, Kyung Kate; Jeong, Kyungsoo; Tok, Andre; Ritchie, Stephen G

2018-03-12

Trucks have distinct driving characteristics in general traffic streams such as lower speeds and limitations in acceleration and deceleration. As a consequence, vehicles keep longer headways or frequently change lane when they follow a truck, which is expected to increase crash risk. This study introduces several traffic measures at the individual vehicle level to capture vehicle interactions between trucks and non-trucks and analyzed how the measures affect crash risk under different traffic conditions. The traffic measures were developed using headways obtained from Inductive Loop Detectors (ILDs). In addition, a truck detection algorithm using a Gaussian Mixture (GM) model was developed to identify trucks and to estimate truck exposure from ILD data. Using the identified vehicle types from the GM model, vehicle interaction metrics were categorized into three groups based on the combination of leading and following vehicle types. The effects of the proposed traffic measures on crash risk were modeled in two different cases of prior- and non-crash using a case-control approach utilizing a conditional logistic regression. Results showed that the vehicle interactions between the leading and following vehicle types were highly associated with crash risk, and further showed different impacts on crash risk by traffic conditions. Specifically, crashes were more likely to occur when a truck following a non-truck had shorter average headway but greater headway variance in heavy traffic while a non-truck following a truck had greater headway variance in light traffic. This study obtained meaningful conclusions that vehicle interactions involved with trucks were significantly related to the crash likelihood rather than the measures that estimate average traffic condition such as total volume or average headway of the traffic stream. Copyright © 2018 Elsevier Ltd. All rights reserved.

Design committee makes major headway

International Nuclear Information System (INIS)

Anon.

1998-01-01

Work of Ontario's Market Design Committee (MDC), charged with recommending the detailed steps to restructuring the electric power industry in Ontario was described. In its short life of only a few weeks, MDC had to create a series of strenuous internal rules in order to accomplish the enormous task of restructuring the industry in the relatively short time set out in the Government's White Paper in February 1998. Most of this article is devoted to describing the nature and functions of the Independent Market Operator (IMO), more commonly referred to as the Independent System Operator or the dispatch and control centre for the electrical system. The IMO will be governed by a board of 15 members consisting of a CEO, end-users, generation providers, marketers and transmission providers. Five independent members will be appointed by the Government from a list suggested by market participants to represent the broad industry and public interest. The IMO will be created as a not-for-profit, statutory corporation using a special act of the Ontario Legislature. Special needs identified by MDC will be drawn mostly from the Ontario Corporation Act, with operating procedures included as by-laws. The Ontario Energy Board (OEB) and the IMO are envisaged as having a relationship somewhat similar to the Ontario Securities Commission's role in overseeing the Toronto Stock Exchange. The involvement of the Independent Power Producers' Society of Ontario (IPPSO) in the work of the MDC is also described

Task-Difficulty Homeostasis in Car Following Models: Experimental Validation Using Self-Paced Visual Occlusion.

Directory of Open Access Journals (Sweden)

Jami Pekkanen

Full Text Available Car following (CF models used in traffic engineering are often criticized for not incorporating "human factors" well known to affect driving. Some recent work has addressed this by augmenting the CF models with the Task-Capability Interface (TCI model, by dynamically changing driving parameters as function of driver capability. We examined assumptions of these models experimentally using a self-paced visual occlusion paradigm in a simulated car following task. The results show strong, approximately one-to-one, correspondence between occlusion duration and increase in time headway. The correspondence was found between subjects and within subjects, on aggregate and individual sample level. The long time scale aggregate results support TCI-CF models that assume a linear increase in time headway in response to increased distraction. The short time scale individual sample level results suggest that drivers also adapt their visual sampling in response to transient changes in time headway, a mechanism which isn't incorporated in the current models.

Travel Time Model for Right-Turning Vehicles of Secondary Street at Unsignalized Intersections

Directory of Open Access Journals (Sweden)

Feng Yu-Qin

2013-01-01

Full Text Available The travel time of right-turning vehicles on secondary street at unsignalized intersection is discussed in this paper. Under the assumption that the major-street through vehicles’ headway follows Erlang distribution and secondary-street right-turning vehicles’ headway follows Poisson distribution. The right-turning vehicles travel time model is established on the basis of gap theory and M/G/1 queue theory. Comparison is done with the common model based on the assumption that the major-street vehicles’ headway follows Poisson distribution. An intersection is selected to verify each model. The results show that the model established in this paper has stronger applicability, and its most relative error is less than 15%. In addition, the sensitivity analysis has been done. The results show that right-turning flow rate and major-street flow rate have a significant impact on the travel time. Hence, the methodology for travel time of right-turning vehicles at unsignalized intersection proposed in this paper is effective and applicable.

Passenger arrival and waiting time distributions dependent on train service frequency and station characteristics: A smart card data analysis

DEFF Research Database (Denmark)

Ingvardson, Jesper Bláfoss; Nielsen, Otto Anker; Raveau, Sebastián

2018-01-01

Waiting time at public transport stops is perceived by passengers to be more onerous than in-vehicle time, hence it strongly influences the attractiveness and use of public transport. Transport models traditionally assume that average waiting times are half the service headway by assuming random...... Copenhagen Area covering metro, suburban, and regional rail stations thereby giving a range of service headways from 2 to 60 min. It was shown that the proposed mixture distribution is superior to other distributions proposed in the literature. This can improve waiting time estimations in public transport...

Headway on co-digestion of wastes

International Nuclear Information System (INIS)

Gokhale, Yogeshwar

2013-01-01

Full text: Many wastewater treatment plants (WWTPs) in Australia produce biogas either directly from the wastewater or from anaerobic digestion of the primary and/or secondary sludge, which in turn is used to create energy. Some WWTPs produce electricity from the biogas to either support the treatment plant or to export the electricity to the grid or both. High-strength organic wastes such as fats, oil and grease, food waste, commercial (restaurant) waste and brewery waste are attractive biogas sources that can be realised through co-digestion with the sludge from wastewater treatment. Co-digestion of high-strength waste can be a tricky business due to the varying nature of the waste, special handling requirements, and potential digester process issues like foaming. However, experiences over the past decade have helped identify mitigation measures and advanced designs to reduce these risks. Several WWTPs in the US accept fats, oil and grease (FOG) as a feedstock for co-digestion, and CH2M Hill has been involved in various capacities on some of those projects. The Douglas L. Smith Middle Basin Wastewater Treatment Plant (WWTP) in Johnson County, Kansas, includes an environmentally friendly approach for the treatment of FOG wastes from local restaurants and industrial sources. FOG waste receipts are handled using a separate onsite liquid receiving facility, and the FOG tanks and pipes are heated to minimise clogging. Co-digestion of FOG enhanced the gas production to fuel a 2.1 megawatt biogas co-generation system. Other CH2M Hill FOG co-digestion projects are FOG addition to the incinerator at the Hampton Roads Sanitation District in Virginia; FOG co-digestion at the Pinellas County in Florida; and FOG co-digestion and co-generation at the Essex Junction in Vermont. This experience was recently expanded to the co-digestion of other high-strength organic waste for Yarra Valley Water (YVW) and City West Water (CWW) in Victoria. The potential high-strength waste streams investigated were diverse and included food waste, cheese whey processing waste, brewery waste, FOG, poultry waste, beef and sheep abattoir waste and vegetable market waste. The preliminary findings of the YVW study showed favourable economic analysis and resulted in YVW inviting tenders for assistance in design, construction and operation of the waste to energy facility in July 2012. The higher level of accuracy achieved through the tendering process will provide more certainty to the business case, and the waste to energy facility will be built subject to business case verification. The facility is proposed to be co-located with a wastewater treatment plant. CWW is currently reviewing the concept design report for a Resource Recovery Centre (RCC) to consider the benefits sustainable organic waste management may deliver to its customers and community by beneficial reuse of water, energy and solids and the barriers that need to be overcome. The most commonly used technologies for digestion are mesophilic anaerobic digestion (MAD), thermophilic anaerobic digestion (TAD), temperature phased anaerobic digestion (TPAD) and acid-gas (AG) phased anaerobic digestion. The high temperature processes (TAD and TPAD) are not well suited for small facilities, and though MAD is well suited to small facilities it typically has medium process stability and potential for high strength waste to breakthrough. The acid-gas phased digestion is an appropriate process, which is more stable due to separate digesters for acidification and methane production, has lower risk of process failure, has comparable capital and operating cost, and a smaller footprint when compared to the other available technologies. Though the acid-gas phased digestion has advantages over other processes, the selected technology largely depends on the method of procurement (design-build-operate, design and construct, build-own-operate-transfer etc) and on the experience of involved parties with the various technologies. Co-digestion of high-strength waste includes a waste receiving station, which generally consists of individual pre-treatment waste holding tanks, some of which are required to be mixed and heated. The waste streams are then blended to allow constant and controlled feed into the anaerobic digesters.

Impact of mobile phone use on car-following behaviour of young drivers.

Science.gov (United States)

Saifuzzaman, Mohammad; Haque, Md Mazharul; Zheng, Zuduo; Washington, Simon

2015-09-01

Multitasking, such as the concurrent use of a mobile phone and operating a motor vehicle, is a significant distraction that impairs driving performance and is becoming a leading cause of motor vehicle crashes. This study investigates the impact of mobile phone conversations on car-following behaviour. The CARRS-Q Advanced Driving Simulator was used to test a group of young Australian drivers aged 18-26 years on a car-following task in three randomised phone conditions: baseline (no phone conversation), hands-free and handheld. Repeated measure ANOVA was applied to examine the effect of mobile phone distraction on selected car-following variables such as driving speed, spacing, and time headway. Overall, drivers tended to select slower driving speeds, larger vehicle spacings, and longer time headways when they were engaged in either hands-free or handheld phone conversations, suggesting possible risk compensatory behaviour. In addition, phone conversations while driving influenced car-following behaviour such that variability was increased in driving speeds, vehicle spacings, and acceleration and decelerations. To further investigate car-following behaviour of distracted drivers, driver time headways were modelled using Generalized Estimation Equation (GEE). After controlling for various exogenous factors, the model predicts an increase of 0.33s in time headway when a driver is engaged in hands-free phone conversation and a 0.75s increase for handheld phone conversation. The findings will improve the collective understanding of distraction on driving performance, in particular car following behaviour which is most critical in the determination of rear-end crashes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Moving characteristics of single file passengers considering the effect of ship trim and heeling

Science.gov (United States)

Sun, Jinlu; Lu, Shouxiang; Lo, Siuming; Ma, Jian; Xie, Qimiao

2018-01-01

Ship listing and motion affects the movement pattern of passengers on board, thus pedestrian traffic and evacuation dynamics would be significantly different from those on level ground. To quantify the influence of ship listing and motion on passenger evacuation, we designed a ship corridor simulator, with which we performed single-file pedestrian movement experiments considering the effect of trim and heeling. Results indicated that density is not the only factor that affects pedestrian speed under ship trim or heeling conditions, for that both individual walking speed and group walking speed would be greatly attenuated due to the influence of the trim angles. However, heeling angles show less impact on speed when compared with trim angles. In addition, the speed correlation coefficient between the adjacent experimental subjects would be higher with larger angles and lower speed. Moreover, both female and male experimental subjects need similar distance headway for walking in different trim or heeling conditions. Furthermore, experimental subjects with lower individual walking speed need longer time headway to keep enough distance headway. This work will provide fundamental guidance to the development of evacuation models and the design of evacuation facilities on board.

Vehicle safety telemetry for automated highways

Science.gov (United States)

Hansen, G. R.

1977-01-01

The emphasis in current, automatic vehicle testing and diagnosis is primarily centered on the proper operation of the engine. Lateral and longitudinal guidance technologies, including speed control and headway sensing for collision avoidance, are reviewed. The principal guidance technique remains the buried wire. Speed control and headway sensing, even though they show the same basic elements in braking and fuel systems, are proceeding independently. The applications of on-board electronic and microprocessor techniques were investigated; each application (emission control, spark advance, or anti-slip braking) is being treated as an independent problem is proposed. A unified bus system of distributed processors for accomplishing the various functions and testing required for vehicles equipped to use automated highways.

Chinese-American headway on some environmental issues

Science.gov (United States)

Showstack, Randy

Although Chinese Premier Zhu Rongji may have failed to gain entrance for his country into the World Trade Organization during his April visit to the United States, the two countries concluded a series of agreements as part of the Second Session of the 2-year-old U.S.-China Policy Forum on Environment and Development.A memorandum of understanding on a $100 million clean energy program accelerates the export of clean U.S. environmental technologies in the area of energy efficiency renewable energy, and pollution reduction. A statement of intent on the development of a Sulfur Dioxide (SO2) Emissions Trading Feasibility Study calls for China to develop a study to test the effectiveness of emissions trading in China as a market-based approach to reducing greenhouse gas emissions. And a Memorandum of Understanding on a natural gas pipeline project, signed by the Enron Corporation and the China National Petroleum Corporation, opens the way to jointly developing a natural gas pipeline to help offer an alternative to fossil fuels.

The Feedback Control Strategy of the Takagi-Sugeno Fuzzy Car-Following Model with Two Delays

Directory of Open Access Journals (Sweden)

Cong Zhai

2016-01-01

Full Text Available Considering the driver’s sensing the headway and velocity the different time-varying delays exist, respectively, and the sensitivity of drivers changes with headway and speed. Introducing the fuzzy control theory, a new fuzzy car-following model with two delays is presented, and the feedback control strategy of the new fuzzy car-following model is studied. Based on the Lyapunov function theory and linear matrix inequality (LMI approach, the sufficient condition that the existence of the fuzzy controller is given making the closed-loop system is asymptotic, stable; namely, traffic congestion phenomenon can effectively be suppressed, and the controller gain matrix can be obtained via solving linear matrix inequality. Finally, the simulation examples verify that the method which suppresses traffic congestion and reduces fuel consumption and exhaust emissions is effective.

Manager responses to employee dissent about psychological contract breach : A dyadic process approach

NARCIS (Netherlands)

de Ruiter, M.; Schalk, Rene; Blomme, R.J.

2016-01-01

Communication scholars have made significant headway toward understanding the upward dissent process, conceptualizing different types of upward dissent strategies and investigating the use of these strategies. However, scholars have hardly considered the dyadic process associated with upward dissent

Theoretical predictions for vehicular headways and their clusters

Science.gov (United States)

Krbálek, Milan

2013-11-01

This paper presents a derivation of analytical predictions for steady-state distributions of netto time gaps among clusters of vehicles moving inside a traffic stream. Using the thermodynamic socio-physical traffic model with short-ranged repulsion between particles (originally introduced in Krbálek and Helbing 2004 Physica A 333 370) we first derive the time-clearance distribution in the model and confront it with relation to the theoretical criteria for the acceptability of analytical clearance distributions. Consecutively, the approximating statistical distributions for the so-called time multi-clearances are calculated by means of the theory of functional convolutions. Moreover, all the theoretical surmises used during the above-mentioned calculations are evaluated by the statistical analysis of traffic data. The mathematical predictions acquired in this paper are thoroughly compared with relevant empirical quantities and discussed in the context of traffic theory.

A Real-Time Holding Decision Rule Accounting for Passenger Travel Cost

NARCIS (Netherlands)

Laskaris,; Cats, O.; Jenelius, E; Viti, F

2016-01-01

Holding has been extensively investigated as a strategy to mitigate the inherently stochastic nature of public transport operations. Holding focuses on either regulating vehicle headways using a rule-based approach or minimizing passenger travel cost by employing optimization models. This paper

Individual and Synergetic Effects of Transit Service Improvement Strategies : Simulation and Validation

NARCIS (Netherlands)

West, J; Cats, O.

2017-01-01

Assessment of transit service improvements such as bus lanes, allowing boarding through all doors, and headway-based holding control requires detailed simulation capabilities. However, because the usage of models advanced enough to simultaneously analyze physical and operational measures has been

Workspace and sensorimotor theories : Complementary approaches to experience

NARCIS (Netherlands)

Degenaar, J.; Keijzer, F.

A serious difficulty for theories of consciousness is to go beyond mere correlation between physical processes and experience. Currently, neural workspace and sensorimotor contingency theories are two of the most promising approaches to make any headway here. This paper explores the relation between

Evaluating transit preferential measures : Priority lanes, boarding and control strategies

NARCIS (Netherlands)

West, J.; Cats, O.

2015-01-01

Assessment of bus service improvements such as bus lanes, allowing boarding through all doors and headway-based holding control ideally requires a simulation model that combines features of both classical analytical models and microscopic simulation. However, as the usage of such models has been

Toward Real-time Multi-criteria Decision Making for Bus Service Reliability Optimisation

DEFF Research Database (Denmark)

Tran, Vu The; Eklund, Peter; Cook, Chris

2015-01-01

factors (such as traffic congestion and bad weather) in high frequency transit operations often cause irregular headway that can result in decreased service reliability. The approach proposed in this paper, which has the capability of handling the uncertainty of transit operations based on Multi...

The X-factor : A longitudinal study of calibration in young novice drivers

NARCIS (Netherlands)

De Craen, S.

2010-01-01

It is often assumed that young novice drivers overestimate their driving skills and underestimate the risks in traffic; and therefore insufficiently adapt their driving behaviour (e.g. speed or headway) to the specific situation. This balancing of skills and task demands has been called calibration.

Behavioural effects of advanced cruise control use : a meta-analytic approach.

NARCIS (Netherlands)

Dragutinovic, N. Brookhuis, K.A. Hagenzieker, M.P. & Marchau, V.A.W.J.

2006-01-01

In this study, a meta-analytic approach was used to analyse effects of Advanced Cruise Control (ACC) on driving behaviour reported in seven driving simulator studies. The effects of ACC on three consistent outcome measures, namely, driving speed, headway and driver workload have been analysed. The

What is this? Check it out.

CERN Multimedia

Association du personnel

2008-01-01

You feel tired, stressed and are snowed under with work. You cannot sleep; you cannot switch off from work, but are making no headway. You feel that the balance between your working life and private life is in jeopardy. This may be a case of burn-out.

Future Directions in Vulnerability to Depression among Youth: Integrating Risk Factors and Processes across Multiple Levels of Analysis

Science.gov (United States)

Hankin, Benjamin L.

2012-01-01

Depression is a developmental phenomenon. Considerable progress has been made in describing the syndrome, establishing its prevalence and features, providing clues as to its etiology, and developing evidence-based treatment and prevention options. Despite considerable headway in distinct lines of vulnerability research, there is an explanatory gap…

75 FR 19455 - Intent To Prepare an Environmental Impact Statement for the South Bay Metro Green Line Extension...

Science.gov (United States)

2010-04-14

...; and encourage a mode shift to transit, reducing air pollution and Greenhouse Gas emissions. The EIS... completion of the Metro Rapid Bus Program would be included as well as possible additional feeder bus... widening, traffic engineering actions, bus route restructuring, shortened bus headways, expanded use of...

Physics of automated driving in framework of three-phase traffic theory.

Science.gov (United States)

Kerner, Boris S

2018-04-01

We have revealed physical features of automated driving in the framework of the three-phase traffic theory for which there is no fixed time headway to the preceding vehicle. A comparison with the classical model approach to automated driving for which an automated driving vehicle tries to reach a fixed (desired or "optimal") time headway to the preceding vehicle has been made. It turns out that automated driving in the framework of the three-phase traffic theory can exhibit the following advantages in comparison with the classical model of automated driving: (i) The absence of string instability. (ii) Considerably smaller speed disturbances at road bottlenecks. (iii) Automated driving vehicles based on the three-phase theory can decrease the probability of traffic breakdown at the bottleneck in mixed traffic flow consisting of human driving and automated driving vehicles; on the contrary, even a single automated driving vehicle based on the classical approach can provoke traffic breakdown at the bottleneck in mixed traffic flow.

Using Data Mining Techniques on APC Data to Develop Effective Bus Scheduling Plans

Directory of Open Access Journals (Sweden)

Jayakrishna PATNAIK

2006-02-01

Full Text Available Various trip generators (e.g., buildings, shopping malls, recreational centers continually influence travel demand in urban and suburban areas. As a result, the headway regularity that should be kept among transit vehicles is difficult to maintain, specifically during peak hours. The variation of headways lengthens the average wait times and deteriorates service quality. Providing a tool to monitor and maintain most up-to-date information through Advanced Traveler Information Systems (ATIS can assist effective system planning and scheduling, while reducing the door-to-door travel time. This paper develops a methodology for clustering the state variables (number served passengers and halting stations in each vehicle trip and using that for service planning. The data used to develop the models were collected by Automatic Passenger Counters (APC on buses operated by a transit agency in the northeast region of the United States. The results illustrate that the developed tool can provide suggestions for improving systems performance as well as future planning.

An extended car-following model considering random safety distance with different probabilities

Science.gov (United States)

Wang, Jufeng; Sun, Fengxin; Cheng, Rongjun; Ge, Hongxia; Wei, Qi

2018-02-01

Because of the difference in vehicle type or driving skill, the driving strategy is not exactly the same. The driving speeds of the different vehicles may be different for the same headway. Since the optimal velocity function is just determined by the safety distance besides the maximum velocity and headway, an extended car-following model accounting for random safety distance with different probabilities is proposed in this paper. The linear stable condition for this extended traffic model is obtained by using linear stability theory. Numerical simulations are carried out to explore the complex phenomenon resulting from multiple safety distance in the optimal velocity function. The cases of multiple types of safety distances selected with different probabilities are presented. Numerical results show that the traffic flow with multiple safety distances with different probabilities will be more unstable than that with single type of safety distance, and will result in more stop-and-go phenomena.

Physics of automated driving in framework of three-phase traffic theory

Science.gov (United States)

Kerner, Boris S.

2018-04-01

We have revealed physical features of automated driving in the framework of the three-phase traffic theory for which there is no fixed time headway to the preceding vehicle. A comparison with the classical model approach to automated driving for which an automated driving vehicle tries to reach a fixed (desired or "optimal") time headway to the preceding vehicle has been made. It turns out that automated driving in the framework of the three-phase traffic theory can exhibit the following advantages in comparison with the classical model of automated driving: (i) The absence of string instability. (ii) Considerably smaller speed disturbances at road bottlenecks. (iii) Automated driving vehicles based on the three-phase theory can decrease the probability of traffic breakdown at the bottleneck in mixed traffic flow consisting of human driving and automated driving vehicles; on the contrary, even a single automated driving vehicle based on the classical approach can provoke traffic breakdown at the bottleneck in mixed traffic flow.

Modeling and Simulation of Bus Dispatching Policy for Timed Transfers on Signalized Networks

Science.gov (United States)

Cho, Hsun-Jung; Lin, Guey-Shii

2007-12-01

The major work of this study is to formulate the system cost functions and to integrate the bus dispatching policy with signal control. The integrated model mainly includes the flow dispersion model for links, signal control model for nodes, and dispatching control model for transfer terminals. All such models are inter-related for transfer operations in one-center transit network. The integrated model that combines dispatching policies with flexible signal control modes can be applied to assess the effectiveness of transfer operations. It is found that, if bus arrival information is reliable, an early dispatching decision made at the mean bus arrival times is preferable. The costs for coordinated operations with slack times are relatively low at the optimal common headway when applying adaptive route control. Based on such findings, a threshold function of bus headway for justifying an adaptive signal route control under various time values of auto drivers is developed.

Pedestrian ascent and descent fundamental diagram on stairway

Science.gov (United States)

Chen, Juan; Lo, S. M.; Ma, Jian

2017-08-01

Due to the interaction among individuals, pedestrian walking speeds in relatively dense crowds when descending and ascending stairs may present different features from a single pedestrian moving freely. Thus, to obtain a large range of densities, a series of single-file pedestrian movement experiments under laboratory conditions were performed. The trends of the fundamental diagram in a wide pedestrian density range for staircase movement are captured. Detailed features of pedestrian speed with the increase of pedestrian density, headway, and the influence of pedestrians’ lateral sway are further discussed. It is found that with the increase of pedestrian density, the speed decrease rate varies. Meanwhile, the decrease of headway, leads to two speed regimes, i.e. free movement and linear constrained movement. We show that pedestrian speed can be described by counting the number of steps separating pedestrians in longitudinal direction. These enrichments can benefit pedestrian modelling and improve the evaluation of the evacuation performance of a staircase.

Semantic False Memories in the Form of Derived Relational Intrusions Following Training

Science.gov (United States)

Guinther, Paul M.; Dougher, Michael J.

2010-01-01

Contemporary behavior analytic research is making headway in characterizing memory phenomena that typically have been characterized by cognitive models, and the current study extends this development by producing "false memories" in the form of functional equivalence responding. A match-to-sample training procedure was administered in order to…

Anticipation and the adaptive control of safety margins in driving

NARCIS (Netherlands)

van der Hulst, M.; Meijman, T.F.; Rothengatter, J.A.

Driving is a task that requires the timely detection of critical events and relevant changes in traffic circumstances. Adaptation of speed and safety margins allows drivers to control the time available to react to potential hazards. One of the basic safety margins in driving is the time headway

Factors influencing compliance to tactical driver advice: an assessment using a think-aloud protocol

NARCIS (Netherlands)

Risto, Malte; Martens, Marieke Hendrikje

2013-01-01

Connected Cruise Control (CCC) is an in-car driver support systems that aims to improve throughput in dense motorway traffic by advising drivers how to drive. The system is currently under development within a HTAS project. It will integrate lane advice, headway advice and speed advice. CCC will not

Multijam Solutions in Traffic Models with Velocity-Dependent Driver Strategies

DEFF Research Database (Denmark)

Carter, Paul; Christiansen, Peter Leth; Gaididei, Yuri B.

2014-01-01

The optimal-velocity follow-the-leader model is augmented with an equation that allows each driver to adjust their target headway according to the velocity difference between the driver and the car in front. In this more detailed model, which is investigated on a ring, stable and unstable multipu...

77 FR 63669 - Notice of FTA Transit Program Changes, Authorized Funding Levels and Implementation of the Moving...

Science.gov (United States)

2012-10-16

... public transit vehicles, and short headway bi-directional services for a substantial part of weekdays and... selected through an area-wide or statewide competitive selection process by the designated recipient. Under... transportation plan and must also be selected through an area-wide or statewide competitive selection process by...

Immigrant performance in the labour market: bonding and bridging social capital

NARCIS (Netherlands)

Lancee, B.

2012-01-01

To what extent can different forms of social capital help immigrants make headway on the labour market? An answer to this pressing question begins here. Taking the Netherlands and Germany as case studies, the book identifies two forms of social capital that may work to increase employment, income

Identification of Visual Cues and Quantification of Drivers' Perception of Proximity Risk to the Lead Vehicle in Car-Following Situations

Science.gov (United States)

Kondoh, Takayuki; Yamamura, Tomohiro; Kitazaki, Satoshi; Kuge, Nobuyuki; Boer, Erwin Roeland

Longitudinal vehicle control and/or warning technologies that operate in accordance with drivers' subjective perception of risk need to be developed for driver-support systems, if such systems are to be used fully to achieve safer, more comfortable driving. In order to accomplish this goal, it is necessary to identify the visual cues utilized by drivers in their perception of risk when closing on the vehicle ahead in a car-following situation. It is also necessary to quantify the relation between the physical parameters defining the spatial relationship to the vehicle ahead and psychological metrics with regard to the risk perceived by the driver. This paper presents the results of an empirical study on quantification and formulization of drivers' subjective perception of risk based on experiments performed with a fixed-base driving simulator at the Nissan Research Center. Experiments were carried out to investigate the subjective perception of risk relative to the headway distance and closing velocity to the vehicle ahead using the magnitude estimation method. The experimental results showed that drivers' perception of risk was strongly affected by two variables: time headway, i.e., the distance to the lead vehicle divided by the following vehicle's velocity, and time to collision, i.e., the distance to the lead vehicle divided by relative velocity. It was also found that an equation for estimating drivers' perception of risk can be formulated as the summation of the time headway inverse and the time to collision inverse and that this expression can be applied to various approaching situations. Furthermore, the validity of this equation was examined based on real-world driver behavior data measured with an instrumented vehicle.

The Gospel of Foreign Aid: A Theoretical Note | Byusa | Rwanda ...

African Journals Online (AJOL)

The Gospel of Foreign Aid: A Theoretical Note. ... Journal Home > Vol 26 (2012) > ... USD 1 trillion in aid packages – including charitable giving – to Africa over the last fifty years, only few countries are registering modestly improved Gross Domestic Product (GDP) growth and are making some headway in reducing poverty.

Advanced Cruise Control (ACC).

NARCIS (Netherlands)

2008-01-01

Advanced Cruise Control (ACC), also known as adaptive or intelligent cruise control, not only maintains the driver-set vehicle speed, but also adjusts the vehicle's speed to that of a preceding vehicle, and helps to maintain a pre-selected headway time to the vehicle ahead. ACC systems can have a

Automated Merging in a Cooperative Adaptive Cruise Control (CACC) System

NARCIS (Netherlands)

Klein Wolterink, W.; Heijenk, Geert; Karagiannis, Georgios

2011-01-01

Cooperative Adaptive Cruise Control (CACC) is a form of cruise control in which a vehicle maintains a constant headway to its preceding vehicle using radar and vehicle-to-vehicle (V2V) communication. Within the Connect & Drive1 project we have implemented and tested a prototype of such a system,

Automated Merging in a Cooperative Adaptive Cruise Control (CACC) System

NARCIS (Netherlands)

Klein Wolterink, W.; Karagiannis, Georgios; Brogle, Marc; Masip Bruin, Xavier; Braun, Torsten; Heijenk, Gerhard J.

Cooperative Adaptive Cruise Control (CACC) is a form of cruise control in which a vehicle maintains a constant headway to its preceding vehicle using radar and vehicle-to-vehicle (V2V) communication. Within the Connect & Drive1 project we have implemented and tested a prototype of such a system,

Attachments to places and activities: the relationship of psychological constructs to customer satisfaction attributes

Science.gov (United States)

Thomas D. Wickham; Alan R. Graefe

2002-01-01

This study explores the nature of place attachment, enduring involvement and human territoriality and their relationship with customer satisfaction for a diverse group of anglers at lakes in the New England region. Previous work has made limited headway in our understanding of how place attachment, enduring involvement, and human territoriality relate to people's...

Solid Freeform Fabrication Symposium Proceedings Held in Austin, Texas on August 9-11, 1993

Science.gov (United States)

1993-09-01

di Produzione 1611 Headway Circle, Bldg 2 Austin TX 78712 Ed Economia DeirAzienda Austin TX 78754 Corso Duca Abruzzi 24 512 339-2922J fax: 512 339...Street Aeronautical Engineering & Mechanics Ed Economia DellAzienda Tucson AZ 85713 Troy NY 12180 Corso Duca Abruzzi 24 602 792-2616/ fax: 602 792

The Importance of Infrastructure Development to High-Quality Literacy Instruction

Science.gov (United States)

Cohen, David K.; Bhatt, Monica P.

2012-01-01

Although the education community has identified numerous effective interventions for improving the literacy of U.S. schoolchildren, little headway has been made in raising literacy capabilities. David K. Cohen and Monica P. Bhatt, of the University of Michigan, contend that a major obstacle is the organizational structure of the U.S. education…

A trial of retrofitted advisory collision avoidance technology in government fleet vehicles.

Science.gov (United States)

Thompson, James P; Mackenzie, Jamie R R; Dutschke, Jeffrey K; Baldock, Matthew R J; Raftery, Simon J; Wall, John

2018-06-01

In-vehicle collision avoidance technology (CAT) has the potential to prevent crash involvement. In 2015, Transport for New South Wales undertook a trial of a Mobileye 560 CAT system that was installed in 34 government fleet vehicles for a period of seven months. The system provided headway monitoring, lane departure, forward collision and pedestrian collision warnings, using audio and visual alerts. The purpose of the trial was to determine whether the technology could change the driving behaviour of fleet vehicle drivers and improve their safety. The evaluation consisted of three components: (1) analysis of objective data to examine effects of the technology on driving behaviour, (2) analysis of video footage taken from a sample of the vehicles to examine driving circumstances that trigger headway monitoring and forward collision warnings, and (3) a survey completed by 122 of the 199 individuals who drove the trial vehicles to examine experiences with, and attitudes to, the technology. Analysis of the objective data found that the system resulted in changes in behaviour with increased headway and improved lane keeping, but that these improvements dissipated once the warning alerts were switched off. Therefore, the system is capable of altering behaviour but only when it is actively providing alerts. In-vehicle video footage revealed that over a quarter of forward collision warnings were false alarms, in which a warning event was triggered despite there being no vehicle travelling ahead. The surveyed drivers recognised that the system could improve safety but most did not wish to use it themselves as they found it to be distracting and felt that it would not prevent them from having a crash. The results demonstrate that collision avoidance technology can improve driving behaviour but drivers may need to be educated about the potential benefits for their driving in order to accept the technology. Copyright © 2018 Elsevier Ltd. All rights reserved.

A meta-analysis of the effects of texting on driving.

Science.gov (United States)

Caird, Jeff K; Johnston, Kate A; Willness, Chelsea R; Asbridge, Mark; Steel, Piers

2014-10-01

Text messaging while driving is considered dangerous and known to produce injuries and fatalities. However, the effects of text messaging on driving performance have not been synthesized or summarily estimated. All available experimental studies that measured the effects of text messaging on driving were identified through database searches using variants of "driving" and "texting" without restriction on year of publication through March 2014. Of the 1476 abstracts reviewed, 82 met general inclusion criteria. Of these, 28 studies were found to sufficiently compare reading or typing text messages while driving with a control or baseline condition. Independent variables (text-messaging tasks) were coded as typing, reading, or a combination of both. Dependent variables included eye movements, stimulus detection, reaction time, collisions, lane positioning, speed and headway. Statistics were extracted from studies to compute effect sizes (rc). A total sample of 977 participants from 28 experimental studies yielded 234 effect size estimates of the relationships among independent and dependent variables. Typing and reading text messages while driving adversely affected eye movements, stimulus detection, reaction time, collisions, lane positioning, speed and headway. Typing text messages alone produced similar decrements as typing and reading, whereas reading alone had smaller decrements over fewer dependent variables. Typing and reading text messages affects drivers' capability to adequately direct attention to the roadway, respond to important traffic events, control a vehicle within a lane and maintain speed and headway. This meta-analysis provides convergent evidence that texting compromises the safety of the driver, passengers and other road users. Combined efforts, including legislation, enforcement, blocking technologies, parent modeling, social media, social norms and education, will be required to prevent continued deaths and injuries from texting and driving

Weighing Outsourcing

Science.gov (United States)

Mathis, William J.; Jimerson, Lorna

2009-01-01

The Umbridge School District's hot lunch program was hemorrhaging red ink. Each year, the school district poured more money down the sinkhole. At the same time, parents complained about the quality of the school lunches. The food services director always had excuses and nothing really changed. When no headway was evident, the superintendent said…

Advanced cruise control (ACC) : gewenste beleidsmaatregelen bij de invoering van ACC. In opdracht van het Directoraat-Generaal Rijkswaterstaat, Adviesdienst Verkeer en Vervoer AVV.

NARCIS (Netherlands)

Oei, H.-l.

1999-01-01

Advanced Cruise Control (ACC) concerns an `ordinary' cruise control in which the desired speed is fixed manually, but also in which the headway to the vehicle in front is taken into account. Such an ACC system is meant for use on rural roads that are not too busy. The system is not meant to avoid a

Artificial Intelligence: Is the Future Now for A.I.?

Science.gov (United States)

Ramaswami, Rama

2009-01-01

In education, artificial intelligence (AI) has not made much headway. In the one area where it would seem poised to lend the most benefit--assessment--the reliance on standardized tests, intensified by the demands of the No Child Left Behind Act of 2001, which holds schools accountable for whether students pass statewide exams, precludes its use.…

Status and headway of the clinical application of artificial ligaments

Directory of Open Access Journals (Sweden)

Tianwu Chen

2015-01-01

Full Text Available The authors first reviewed the history of clinical application of artificial ligaments. Then, the status of clinical application of artificial ligaments was detailed. Some artificial ligaments possessed comparable efficacy to, and fewer postoperative complications than, allografts and autografts in ligament reconstruction, especially for the anterior cruciate ligament. At the end, the authors focused on the development of two types of artificial ligaments: polyethylene glycol terephthalate artificial ligaments and tissue-engineered ligaments. In conclusion, owing to the advancements in surgical techniques, materials processing, and weaving methods, clinical application of some artificial ligaments so far has demonstrated good outcomes and will become a trend in the future.

Driving with the wandering mind: the effect that mind-wandering has on driving performance.

Science.gov (United States)

Yanko, Matthew R; Spalek, Thomas M

2014-03-01

The principal objective of the present work was to examine the effects of mind state (mind-wandering vs. on-task) on driving performance in a high-fidelity driving simulator. Mind-wandering is thought to interfere with goal-directed thought. It is likely, then, that when driving, mind-wandering might lead to impairments in critical aspects of driving performance. In two experiments, we assess the extent to which mind-wandering interferes with responsiveness to sudden events, mean velocity, and headway distance. Using a car-following procedure in a high-fidelity driving simulator, participants were probed at random times to indicate whether they were on-task at that moment or mind-wandering. The dependent measures were analyzed based on the participant's response to the probe. Compared to when on-task, when mind-wandering participants showed longer response times to sudden events, drove at a higher velocity, and maintained a shorter headway distance. Collectively, these findings indicate that mind-wandering affects a broad range of driving responses and may therefore lead to higher crash risk. The results suggest that situations that are likely associated with mind-wandering (e.g., route familiarity) can impair driving performance.

The adaptive cruise control vehicles in the cellular automata model

International Nuclear Information System (INIS)

Jiang Rui; Wu Qingsong

2006-01-01

This Letter presented a cellular automata model where the adaptive cruise control vehicles are modelled. In this model, the constant time headway policy is adopted. The fundamental diagram is presented. The simulation results are in good agreement with the analytical ones. The mixture of ACC vehicles with manually driven vehicles is investigated. It is shown that with the introduction of ACC vehicles, the jam can be suppressed

Exclusively welded steel track for the magnetic levitation (Maglev) system Transrapid

Energy Technology Data Exchange (ETDEWEB)

Kindmann, R; Schwindt, G

1988-10-01

The development of high-speed magnetic levitation has made enormous headway over the past decade in West Germany. Its operational maturity is forthcoming. The paper exemplifies the high state of development by taking the steel track as example. Design, fabrication, equipment and erection are entered into in detail. Extremely high requirements of accuracy for the shape of track beams form the governing boundary conditions.

Non-proliferation efforts in South Asia

International Nuclear Information System (INIS)

Chellaney, B.

1994-01-01

Southern Asia is one of the most volatile regions in the world because of inter-State and intra-State conflicts. Security in the region highly depends on the rival capabilities of the involved states, Pakistan, India, China. Increased Confidence building and nuclear transparency are becoming more significant issues in attaining stability in the region, although non-proliferation efforts in this region have attained little headway

United States Air Force Civil Engineering Additive Manufacturing Applications: Tools and Jigs

Science.gov (United States)

2016-03-24

Its Potential Impact on Biotechnology and the Chemical Sciences. Analytical Chemistry, Vol. 86, 3240-3253. Halterman, T. (2014, August 28). 3D...2015). 3D Printing Makes Explosive Headway at AFIT. Civil Engineer Magazine , 23(1), 34-35. Smiths Detection. (2015). LCD 3.2E Handheld CWA & TIC...the Fleet’ Program. National Defense Magazine . Tan, A. (2014, Summer). Advanced Ordnance Teaching Materials. The Journal of ERW and Mine Action, 39

Data Fusion for Decision Support

Science.gov (United States)

2014-03-27

that the location information for some commercial roads is copyrighted. However, there is no limit to the reproduction and use of the data provided...NFDRS identifies six basic fuel models (lichens and mosses; marsh grasses and reeds; grasses and forbs; brush, shrubs, and tree reproduction ; trees...dangerous except immediately after ignition. Fires that develop headway in heavy slash or in conifer stands may be unmanageable while the extreme

THE REGULARITY OF INFLUENCE OF TRAFFIC PARAMETERS ON THE PROBABILITY OF REALISATION OF PLANNED PASSENGER TRANSFER AT TRANSFER NODES

Directory of Open Access Journals (Sweden)

G. Samchuk

2017-06-01

Full Text Available The article deals with the definition of traffic parameters that ensure the minimum value of the transfer waiting time for passengers. On the basis of experimental studies results, a regression equation to determine the probability of realisation of the planned transfer between a pair of vehicles was proposed. Using the identified regression equation, the transfer waiting time can be assessed for any headway exceeding 7,5 min.

Time headway in car following and operational performance during unexpected braking

NARCIS (Netherlands)

Brouwer, W.H.; van Winsum, W.

The relation between car-following behaviour and braking performance was studied in a driving simulator. The theoretical perspective was that individual differences in tactical car-driving behaviour may be related to skills on the operational level of the driving task via a process of adaptation. In

Preventing Deadly Conflict

Science.gov (United States)

1997-12-01

34an ounce of type-A botulinal toxin, properly dis- persed, could kill every man, woman , and child in North America. . . just eight ounces of the...attend to the short-term humanitarian needs generated by conflict, frequently a good deal of "wheel- spinning " occurs; little headway is made in...Empire’s millet system, for exam- ple, where the religious leaders of Judaism and several Christian churches were entrusted with arbitrating conflicts

Naval War College Review. Volume 61, Number 4, Autumn 2008

Science.gov (United States)

2008-01-01

activities. Even major international corporations have been unable to make headway. After Dayton, the German auto giant Volkswagen AG attempted to re- build...and opinions expressed in this publication are those of the authors and are not necessarily those of the U.S. government , the U.S. Navy Department, or...Naval War College; selected U.S. government officials and agen- cies; and selected U.S. and international libraries, research centers, publications, and

Performance of an Automated-Mixed-Traffic-Vehicle /AMTV/ System. [urban people mover

Science.gov (United States)

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

1978-01-01

This study analyzes the operation and evaluates the expected performance of a proposed automatic guideway transit system which uses low-speed Automated Mixed Traffic Vehicles (AMTV's). Vehicle scheduling and headway control policies are evaluated with a transit system simulation model. The effect of mixed-traffic interference on the average vehicle speed is examined with a vehicle-pedestrian interface model. Control parameters regulating vehicle speed are evaluated for safe stopping and passenger comfort.

Shelter from the Storm: Optimizing Distribution of Bus Stop Shelters in Los Angeles

OpenAIRE

Law, Philip; Taylor, Brian D.

2010-01-01

The functions of bus stop shelters and factors affecting their placement at stops in transit systems are analyzed. Drawing on information from a variety of sources, current shelter placement policy in Los Angeles was found to be guided principally by the revenue-generating potential of shelter advertisements, secondarily by political concerns over geographic equity, and only peripherally on the basis of bus stop use. Using data on shelter and stop locations, boardings, and headways, a methodo...

Estimating bus passenger waiting times from incomplete bus arrivals data

OpenAIRE

McLeod, F.N.

2007-01-01

This paper considers the problem of estimating bus passenger waiting times at bus stops using incomplete bus arrivals data. This is of importance to bus operators and regulators as passenger waiting time is a key performance measure. Average waiting times are usually estimated from bus headways, that is, time gaps between buses. It is both time-consuming and expensive to measure bus arrival times manually so methods using automatic vehicle location systems are attractive; however, these syste...

A ROAD AHEAD FROM CANCUN? WEIGHING UP SOME GIVE-AND-TAKE SCENARIOS IN A DDA SPIRIT

OpenAIRE

Shakur, Shamim; Rae, Allan N.; Chatterjee, Srikanta

2004-01-01

Given that around 20 percent of the members of the World Trade Organisation (WTO) are identified as least developed countries (LDC's), global trade negotiations, resumed after the Cancun fiasco of September 2003, must address some major development issues in the spirit of the Doha Development Agenda (DDA), if they are to make any headway. This will, predictably, involve some sensible give-and-take not only between the developed countries and the LDC's, but also amongst the LDC's themselves, a...

The Rise of Mobile Technology on the Financial Sector in Zimbabwe

OpenAIRE

Paul Mupfiga; Tafadzwa Padare

2017-01-01

The emergence of technology has revolted the way that the financial industry operates and the increasing use of mobile gadgets has changed the banking system from the traditional brick and mortar building to a virtual system. The sudden rise in use and innovation of smart mobile phones, mobile personal computers, tablets and various other mobile electronic gadgets has resulted in the rise of mobile financial products. Rapid quickening innovative headways are making completely new business sug...

Motorcycle and scooter speeds approaching urban intersections.

Science.gov (United States)

Walton, D; Buchanan, J

2012-09-01

Five urban, uncontrolled T-intersections known to be motorcycle crash 'black spots' were monitored using instrumentation and a roadside observer. Two sets of twelve-hour observations were collected for each site (N≈100,000). Instrumentation recorded the 'events' of vehicles passing to measure, speed, direction, lane position, vehicle type (broadly characterised) and headway. Observers further recorded times of bicycle events, type of motorcycle (scooters or motorcycles), the behaviour of motorcycles and the use of 'high conspicuity' gear such as clothing or helmets. Results establish that motorcycles travel around 10% faster than the other traffic (car mean speed=34.97 km/h), with motorcycles travelling on average 3.3 km/h faster than cars. Motorcycles were 3.4 times more likely to be exceeding the speed limit than cars. Similar results are described for scooters. Also examined are the influences on mean speeds such as the time of day, the presence of a car at the t-intersection, and the influence of free headway. The results are compared for robustness across locations and days. It is concluded that in urban areas motorcycles are travelling significantly faster than other traffic. These findings are discussed against a concern to reduce motorcycle crashes by improving conspicuity and previous research that implicates a 'looked-but-failed-to-see' effect for car drivers. Copyright © 2012 Elsevier Ltd. All rights reserved.

Performance Analysis of Trans-Jakarta Bus Suburban Service Move-Across Greater Jakarta

Science.gov (United States)

Tangkudung, ESW; Widyadayinta, C.

2018-03-01

Trans-Jakarta have developed their services scope as Suburban Service or Feeder move-across service that operate from greater Jakarta into Jakarta central vice versa. One of the route is Ciputat – Bundaran Hotel Indonesia (Tosari) and integrated with corridor 1 (one) and 8 (eight). This service is not travel on the exclusive lane or bus-way. Objective of Government Jakarta to provide this service is to decrease private car to enter the central of Jakarta. The objective of this study is to find the performance of the service. Survey have conducted static and dynamic on work day to get variable of travel time and delay, waiting time of passenger at the bus stop, headway and ridership of the bus. Service Standard Minimum of Trans-Jakarta have compared with the result of variable headway, travel speed, and waiting time at bus stop as concern of all the passengers. Analysis use correlation test method and linear regression model have done. The performance of Trans-Jakarta bus suburban service, based on travel speed indicator is fairly bad, only 8.1% of trip could comply with Minimum Service Standard. Bus performance based on the indicator of density in the bus is good, where all points are below the maximum limit i.e. 8 people/m2 at peak hour and 5 people/m2 at off-peak hour.

Driver headway choice : A comparison between driving simulator and real-road driving

NARCIS (Netherlands)

Risto, M.; Martens, M.H.

2014-01-01

Driving simulators have become an established tool in driver behaviour research by offering a controllable, safe and cost-effective alternative to real world driving. A challenge for using driving simulators as a research tool has been to elicit driving behaviour that equals real world driving. With

Driver headway choice: a comparison between driving simulator and real-road driving

NARCIS (Netherlands)

Risto, Malte; Martens, Marieke Hendrikje

2014-01-01

Driving simulators have become an established tool in driver behaviour research by offering a controllable, safe and cost-effective alternative to real world driving. A challenge for using driving simulators as a research tool has been to elicit driving behaviour that equals real world driving. With

Project SQUID: Quarterly Progress Report

Science.gov (United States)

1950-07-01

JET ENGINES. ( HYU -eÄl) Submitted by» J» Lemeleon^ New York University, No data on the operations of the glass-walled pulse jet have been...It is felt at HYU that a better understanding of the rela- tively simple phenomenon of the Rijke tube is, therefore, essential before headway...tnd combustion, KYTJ-7R6. Lerge amplitude ges vibration theory 19 HyU -7R7. Photo-ignition 1.4 NYU-7R8. Hydrocorbon Fleme Bends 67 i NYU

The value of service reliability

OpenAIRE

Benezech , Vincent; Coulombel , Nicolas

2013-01-01

International audience; This paper studies the impact of service frequency and reliability on the choice of departure time and the travel cost of transit users. When the user has (α, β, γ) scheduling preferences, we show that the optimal head start decreases with service reliability, as expected. It does not necessarily decrease with service frequency, however. We derive the value of service headway (VoSH) and the value of service reliability (VoSR), which measure the marginal effect on the e...

Additive measures of travel time variability

DEFF Research Database (Denmark)

Engelson, Leonid; Fosgerau, Mogens

2011-01-01

This paper derives a measure of travel time variability for travellers equipped with scheduling preferences defined in terms of time-varying utility rates, and who choose departure time optimally. The corresponding value of travel time variability is a constant that depends only on preference...... parameters. The measure is unique in being additive with respect to independent parts of a trip. It has the variance of travel time as a special case. Extension is provided to the case of travellers who use a scheduled service with fixed headway....

Evaluation of the impacts of cooperative adaptive cruise control on reducing rear-end collision risks on freeways.

Science.gov (United States)

Li, Ye; Wang, Hao; Wang, Wei; Xing, Lu; Liu, Shanwen; Wei, Xueyan

2017-01-01

Although plenty of studies have been conducted recently about the impacts of cooperative adaptive cruise control (CACC) system on traffic efficiency, there are few researches analyzing the safety effects of this advanced driving-assistant system. Thus, the primary objective of this study is to evaluate the impacts of the CACC system on reducing rear-end collision risks on freeways. The CACC model is firstly developed, which is based on the Intelligent Driver Model (IDM). Then, two surrogated safety measures, derived from the time-to-collision (TTC), denoting time exposed time-to-collision (TET) and time integrated time-to-collision (TIT), are introduced for quantifying the collision risks. And the safety effects are analyzed both theoretically and experimentally, by the linear stability analysis and simulations. The theoretical and simulation results conformably indicate that the CACC system brings dramatic benefits for reducing rear-end collision risks (TET and TIT are reduced more than 90%, respectively), when the desired time headway and time delay are set properly. The sensitivity analysis indicates there are few differences among different values of the threshold of TTC and the length of a CACC platoon. The results also show that the safety improvements weaken with the decrease of the penetration rates of CACC on the market and the increase of time delay between platoons. We also evaluate the traffic efficiency of the CACC system with different desired time headway. Copyright © 2016 Elsevier Ltd. All rights reserved.

Does Talking on a Cell Phone, With a Passenger, or Dialing Affect Driving Performance? An Updated Systematic Review and Meta-Analysis of Experimental Studies.

Science.gov (United States)

Caird, Jeff K; Simmons, Sarah M; Wiley, Katelyn; Johnston, Kate A; Horrey, William J

2018-02-01

Objective An up-to-date meta-analysis of experimental research on talking and driving is needed to provide a comprehensive, empirical, and credible basis for policy, legislation, countermeasures, and future research. Background The effects of cell, mobile, and smart phone use on driving safety continues to be a contentious societal issue. Method All available studies that measured the effects of cell phone use on driving were identified through a variety of search methods and databases. A total of 93 studies containing 106 experiments met the inclusion criteria. Coded independent variables included conversation target (handheld, hands-free, and passenger), setting (laboratory, simulation, or on road), and conversation type (natural, cognitive task, and dialing). Coded dependent variables included reaction time, stimulus detection, lane positioning, speed, headway, eye movements, and collisions. Results The overall sample had 4,382 participants, with driver ages ranging from 14 to 84 years ( M = 25.5, SD = 5.2). Conversation on a handheld or hands-free phone resulted in performance costs when compared with baseline driving for reaction time, stimulus detection, and collisions. Passenger conversation had a similar pattern of effect sizes. Dialing while driving had large performance costs for many variables. Conclusion This meta-analysis found that cell phone and passenger conversation produced moderate performance costs. Drivers minimally compensated while conversing on a cell phone by increasing headway or reducing speed. A number of additional meta-analytic questions are discussed. Application The results can be used to guide legislation, policy, countermeasures, and future research.

KEY COMPONENTS OF A MOTORCYCLE-TRAFFIC SYSTEM

Directory of Open Access Journals (Sweden)

H. HUSSAIN

2005-01-01

The small- and medium-sized type motorcycles (150c.c. and below made up 99% of the motorcycles population in Malaysia. A static motorcyclist measured about 0.8m in width, 2.0m in length, and requires an operating width of 1.3m. At a lane width of 1.7m or below, motorcycle flow applies the lane or headway concept. Above this optimum value, motorcycle flow adopted the space concept. This implied that a motorcycle path should be more than 1.7m wide to allow two motorcyclists to pass each other.

[Computerized medical record: deontology and legislation].

Science.gov (United States)

Allaert, F A; Dusserre, L

1996-02-01

Computerization of medical records is making headway for patients' follow-up, scientific research, and health expenses control, but it must not alter the guarantees provided to the patients by the medical code of ethics and the law of January 6, 1978. This law, modified on July 1, 1994, requires to register all computerized records of personal data and establishes rights to protect privacy against computer misdemeanor. All medical practitioners using computerized medical records must be aware that the infringement of this law may provoke suing in professional, civil or criminal court.

Gender and teacher training in Early Childhood Education studies

Directory of Open Access Journals (Sweden)

Alfonso Romero Díaz

2008-12-01

Full Text Available This paper presents the findings of a research study funded by the European Union that aims to improve early childhood teacher training in gender-related topics. Spain has made considerable headway with the inclusion of gender mainstreaming in the political agenda. However, as we point out in this paper, this issue is still not a priority in vocational training for early childhood education. A series of qualitative interviews and a quantitative questionnaire revealed a lack of training, materials and sensitivity, all needed for the introduction of gender and sexual diversity issues.

Behavioural aspects of automatic vehicle guidance : the relationship between headway and driver comfort

NARCIS (Netherlands)

Vos, A.P. de; Theeuwes, J.; Hoekstra, W.

1996-01-01

In de rijsimulator is de relatie tussen volgtijd en comfort bij Automatische Voertuiggeleiding (AVG) onderzocht. Gevonden is dat een volgtijd van 0,9 seconden bij AVG overeenkomt met het comfort in druk gewoon verkeer. Een volgtijd van 0,3 seconden in AVG correspondeert met een incident in normaal

Performance analysis of a cooperative adaptive cruise controller subject to dynamic time headway

NARCIS (Netherlands)

Semsar-Kazerooni, E.; Ploeg, J.

2013-01-01

The current paper shows string stability of a platoon of vehicles when the spacing policy within the platoon is dynamic, i.e., it has time-varying parameters. This problem setup is to address the safety issues that arise due to malfunction of some redundant sensing/communicating devices installed on

Slip control for LIM propelled transit vehicles

Science.gov (United States)

Wallace, A. K.; Parker, J. H.; Dawson, G. E.

1980-09-01

Short stator linear induction motors, with an iron-backed aluminum sheet reaction rail and powered by a controlled inverter, have been selected as the propulsion system for transit vehicles in an intermediate capacity system (12-20,000 pphpd). The linear induction motor is capable of adhesion independent braking and acceleration levels which permit safe, close headways. In addition, simple control is possible allowing moving block automatic train control. This paper presents a slip frequency control scheme for the LIM. Experimental results for motoring and braking obtained from a test vehicle are also presented. These values are compared with theoretical predictions.

Self-organization leads to supraoptimal performance in public transportation systems.

Science.gov (United States)

Gershenson, Carlos

2011-01-01

The performance of public transportation systems affects a large part of the population. Current theory assumes that passengers are served optimally when vehicles arrive at stations with regular intervals. In this paper, it is shown that self-organization can improve the performance of public transportation systems beyond the theoretical optimum by responding adaptively to local conditions. This is possible because of a "slower-is-faster" effect, where passengers wait more time at stations but total travel times are reduced. The proposed self-organizing method uses "antipheromones" to regulate headways, which are inspired by the stigmergy (communication via environment) of some ant colonies.

Build of virtual instrument laboratory related to nuclear species specialized

International Nuclear Information System (INIS)

Shan Jian; Zhao Guizhi; Zhao Xiuliang; Tang Lingzhi

2009-01-01

As rapid development of specialized related to nuclear science,the requirement of laboratory construct is analyzed in this article at first, One total conceive, One scheme deploy soft and hardware,three concrete characteristics targets and five different phases of put in practice of virtual instrument laboratory of specialized related to nuclear science are suggest in the paper,the concrete hardware structure and the headway of build of virtual instrument laboratory are described,and the first step effect is introduced.Lastly,the forward target and the further deliberateness that the virtual instrument laboratory construct are set forth in the thesis. (authors)

Reaching out to take on TB in Somalia.

Science.gov (United States)

Moore, David A J; Granat, Simo M

2014-01-01

Among the many challenges facing populations disrupted by complex emergencies, personal security and food security rank much higher than access to healthcare. However, over time health needs assume increasing importance. Many complex crises occur in settings where the background incidence of TB is already high; social and economic conditions in crises are then highly conducive to amplification of the existing TB problem. Innovative approaches to delivery of diagnostic and treatment services, transition planning and integration with other healthcare providers and services are vital. In the extremely challenging environment of Somalia, multiple partners are making headway though collaboration and innovation.

New approach to high-risk pregnancy begins far earlier than traditional programs.

Science.gov (United States)

2002-10-01

Why? Because traditional programs that focus on women as soon as they become pregnant are not making any headway against the incidence of low and very low birth weight (LBW) babies. As a result, while more of these babies are surviving, a significant number have disabilities that will impact them for life while costing the health care system dearly. Experts at Emory University in Atlanta believe there must be a better way to curb the incidence of poor birth outcomes, and they are putting their theories to work in a new program focused on "interpregnancy" care.

Automated mixed traffic vehicle control and scheduling study

Science.gov (United States)

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

1976-01-01

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

Analysis of near crashes among teen, young adult, and experienced adult drivers using the SHRP2 naturalistic driving study.

Science.gov (United States)

Seacrist, Thomas; Douglas, Ethan C; Huang, Elaine; Megariotis, James; Prabahar, Abhiti; Kashem, Abyaad; Elzarka, Ayya; Haber, Leora; MacKinney, Taryn; Loeb, Helen

2018-02-28

Motor vehicle crashes are the leading cause of death among young drivers. Though previous research has focused on crash events, near crashes offer additional data to help identify driver errors that could potentially lead to crashes as well as evasive maneuvers used to avoid them. The Strategic Highway Research Program 2 (SHRP2) Naturalistic Driving Study (NDS) contains extensive data on real-world driving and offers a reliable methodology to quantify and study near crashes. This article presents findings on near crashes and how they compare to crash events among teen, young adult, and experienced adult drivers. A subset from the SHRP2 database consisting of 1,653 near crashes for teen (16-19 years, n = 550), young adult (20-24 years, n = 748), and experienced adult (35-54 years, n = 591) drivers was used. Onboard instrumentation including scene cameras, accelerometers, and Global Positioning System logged time series data at 10 Hz. Scene videos were reviewed for all events to classify near crashes based on 7 types: rear-end, road departure, intersection, head-on, side-swipe, pedestrian/cyclist, and animal. Near crash rates, incident type, secondary tasks, and evasive maneuvers were compared across age groups and between crashes and near crashes. For rear-end near crashes, vehicle dynamic variables including near crash severity, headway distance, time headway, and time to collision at the time of braking were compared across age groups. Crashes and near crashes were combined to compare the frequency of critical events across age. Teen drivers exhibited a significantly higher (P systems based on the most common driving errors for vulnerable road users.

Delay-based Passenger Car Equivalent at Signalized Intersections in Iran

Directory of Open Access Journals (Sweden)

Habibollah Nassiri

2017-04-01

Full Text Available Due to their different sizes and operational characteristics, vehicles other than passenger cars have a different influence on traffic operations especially at intersections. The passenger car equivalent (PCE is the parameter that shows how many passenger cars must be substituted for a specific heavy vehicle to represent its influence on traffic operation. PCE is commonly estimated using headway-based methods that consider the excess headway utilized by heavy vehicles. In this research, the PCE was estimated based on the delay parameter at three signalized intersections in Tehran, Iran. The data collected were traffic volume, travel time for each movement, signalization, and geometric design information. These data were analysed and three different models, one for each intersection, were constructed and calibrated using TRAF-NETSIM simulation software for unsaturated traffic conditions. PCE was estimated under different scenarios and the number of approach movements at each intersection. The results showed that for approaches with only one movement, PCE varies from 1.1 to 1.65. Similarly, for approaches with two and three movements, the PCE varies from 1.07 to 1.99 and from 0.76 to 3.6, respectively. In addition, a general model was developed for predicting PCE for intersections with all of the movements considered. The results obtained from this model showed that the average PCE of 1.5 is similar to the value recommended by the HCM (Highway Capacity Manual 1985. However, the predicted PCE value of 1.9 for saturated threshold is closer to the PCE value of 2 which was recommended by the HCM 2000 and HCM 2010.

Genetics of common forms of heart failure: challenges and potential solutions.

Science.gov (United States)

Rau, Christoph D; Lusis, Aldons J; Wang, Yibin

2015-05-01

In contrast to many other human diseases, the use of genome-wide association studies (GWAS) to identify genes for heart failure (HF) has had limited success. We will discuss the underlying challenges as well as potential new approaches to understanding the genetics of common forms of HF. Recent research using intermediate phenotypes, more detailed and quantitative stratification of HF symptoms, founder populations and novel animal models has begun to allow researchers to make headway toward explaining the genetics underlying HF using GWAS techniques. By expanding analyses of HF to improved clinical traits, additional HF classifications and innovative model systems, the intractability of human HF GWAS should be ameliorated significantly.

Traffic Modelling for Moving-Block Train Control System

International Nuclear Information System (INIS)

Tang Tao; Li Keping

2007-01-01

This paper presents a new cellular automaton (CA) model for train control system simulation. In the proposed CA model, the driver reactions to train movements are captured by some updated rules. The space-time diagram of traffic flow and the trajectory of train movement is used to obtain insight into the characteristic behavior of railway traffic flow. A number of simulation results demonstrate that the proposed CA model can be successfully used for the simulations of railway traffic. Not only the characteristic behavior of railway traffic flow can be reproduced, but also the simulation values of the minimum time headway are close to the theoretical values.

Revisiting the Competitiveness of Romanian Manufacturing Industry

Directory of Open Access Journals (Sweden)

Ovidiu RUJAN

2007-01-01

Full Text Available Since the early 1990s the Romanian manufacturing industry has improved in many ways. This headway concerns the labour-intensive sector rather than the technology-intensive one. Apart from local entrepreneurship, foreign direct investments (FDI have been instrumental in enhancing industrial competitiveness. TheLisbon Agenda revival and Romania’s EU accession will be further inducements for Western businesses to shift production here to fight back both low-cost producers (typically from emerging Asia and more quality-oriented producers (typically from OECD countries. Hopefully, the FDI spillover effects will send positive vibrationsacross the economy, and tone down the asymmetry at the core of the manufacturing industry.

Estimation of red-light running frequency using high-resolution traffic and signal data.

Science.gov (United States)

Chen, Peng; Yu, Guizhen; Wu, Xinkai; Ren, Yilong; Li, Yueguang

2017-05-01

Red-light-running (RLR) emerges as a major cause that may lead to intersection-related crashes and endanger intersection safety. To reduce RLR violations, it's critical to identify the influential factors associated with RLR and estimate RLR frequency. Without resorting to video camera recordings, this study investigates this important issue by utilizing high-resolution traffic and signal event data collected from loop detectors at five intersections on Trunk Highway 55, Minneapolis, MN. First, a simple method is proposed to identify RLR by fully utilizing the information obtained from stop bar detectors, downstream entrance detectors and advance detectors. Using 12 months of event data, a total of 6550 RLR cases were identified. According to a definition of RLR frequency as the conditional probability of RLR on a certain traffic or signal condition (veh/1000veh), the relationships between RLR frequency and some influential factors including arriving time at advance detector, approaching speed, headway, gap to the preceding vehicle on adjacent lane, cycle length, geometric characteristics and even snowing weather were empirically investigated. Statistical analysis shows good agreement with the traffic engineering practice, e.g., RLR is most likely to occur on weekdays during peak periods under large traffic demands and longer signal cycles, and a total of 95.24% RLR events occurred within the first 1.5s after the onset of red phase. The findings confirmed that vehicles tend to run the red light when they are close to intersection during phase transition, and the vehicles following the leading vehicle with short headways also likely run the red light. Last, a simplified nonlinear regression model is proposed to estimate RLR frequency based on the data from advance detector. The study is expected to helpbetter understand RLR occurrence and further contribute to the future improvement of intersection safety. Copyright © 2017 Elsevier Ltd. All rights reserved.

Traffic and random processes an introduction

CERN Document Server

Mauro, Raffaele

2015-01-01

This book deals in a basic and systematic manner with a the fundamentals of random function theory and looks at some aspects related to arrival, vehicle headway and operational speed processes at the same time. The work serves as a useful practical and educational tool and aims at providing stimulus and motivation to investigate issues of such a strong applicative interest. It has a clearly discursive and concise structure, in which numerical examples are given to clarify the applications of the suggested theoretical model. Some statistical characterizations are fully developed in order to illustrate the peculiarities of specific modeling approaches; finally, there is a useful bibliography for in-depth thematic analysis.

Stability of the car-following model on two lanes

Science.gov (United States)

Tang, Tie-Qiao; Huang, Hai-Jun; Gao, Zi-You

2005-12-01

In the case of two-lane traffic, vehicle drivers always worry about the lane changing actions from neighbor lane. This paper studies the stability of a car-following model on two lanes which incorporates the lateral effects in traffic. The stability condition of the model is obtained by using the linear stability theory. The modified Korteweg-de Vries equation is constructed and solved, and three types of traffic flows in the headway-sensitivity space—stable, metastable, and unstable—are classified. Both analytical and simulation results show that the anxiousness about lane changing from neighbor lane indeed has influence upon people’s driving behavior and the consideration of lateral effects could stabilize the traffic flows on both lanes.

Elementary Particles The first hundred years

CERN Document Server

Perkins, Donald Hill

1997-01-01

To mark the centenary of the discovery of that first elementary particle, the electron, some remarks and recollections from the early days of high energy physics, including the impact of early experiments and ideas on todayÕs research. Much of our progress in this field has been carefully anticipated and planned, but a surprising number of successes were the result of incredibly lucky breaks, where headway was made despite - or even because of - incorrect experimental results, crossed wires or simply asking the wrong question at the right time. We can be sure therefore that the next century - or perhaps even what remains of this one - will have unexpected surprises in store.

Modeling no-jam traffic in ant trails: a pheromone-controlled approach

Science.gov (United States)

Guo, Ning; Hu, Mao-Bin; Jiang, Rui; Ding, Jianxun; Ling, Xiang

2018-05-01

The experiment in John et al (2009 Phys. Rev. Lett. 102 108001) shows that when ants move in a single-file trail, no jam emerges even at very high densities. We propose a self-propelled model of ant traffic to reproduce the fundamental diagram without a jammed branch. In this model, ants can adjust their desired velocities actively by perceiving pheromone concentration near the front of the trail. Moreover, ants will bear the repulsive force when they have physical contact with neighbors. The velocity in the simulation decreases slightly with increasing density, which captures the main feature observed in the experiment. Distributions of velocity and distance headway basically also conform to the experimental ones.

Optimization of ACC system spacing policy on curved highway

Science.gov (United States)

Ma, Jun; Qian, Kun; Gong, Zaiyan

2017-05-01

The paper optimizes the original spacing policy when adopting VTH (Variable Time Headway), proposes to introduce the road curve curvature K to the spacing policy to cope with following the wrong vehicle or failing to follow the vehicle owing to the radar limitation of curve in ACC system. By utilizing MATLAB/Simulink, automobile longitudinal dynamics model is established. At last, the paper sets up such three common cases as the vehicle ahead runs at a uniform velocity, an accelerated velocity and hits the brake suddenly, simulates these cases on the curve with different curvature, analyzes the curve spacing policy in the perspective of safety and vehicle following efficiency and draws the conclusion whether the optimization scheme is effective or not.

Control techniques for an automated mixed traffic vehicle

Science.gov (United States)

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.

Discrete event model-based simulation for train movement on a single-line railway

International Nuclear Information System (INIS)

Xu Xiao-Ming; Li Ke-Ping; Yang Li-Xing

2014-01-01

The aim of this paper is to present a discrete event model-based approach to simulate train movement with the considered energy-saving factor. We conduct extensive case studies to show the dynamic characteristics of the traffic flow and demonstrate the effectiveness of the proposed approach. The simulation results indicate that the proposed discrete event model-based simulation approach is suitable for characterizing the movements of a group of trains on a single railway line with less iterations and CPU time. Additionally, some other qualitative and quantitative characteristics are investigated. In particular, because of the cumulative influence from the previous trains, the following trains should be accelerated or braked frequently to control the headway distance, leading to more energy consumption. (general)

The value of travel time variance

DEFF Research Database (Denmark)

Fosgerau, Mogens; Engelson, Leonid

2011-01-01

This paper considers the value of travel time variability under scheduling preferences that are defined in terms of linearly time varying utility rates associated with being at the origin and at the destination. The main result is a simple expression for the value of travel time variability...... that does not depend on the shape of the travel time distribution. The related measure of travel time variability is the variance of travel time. These conclusions apply equally to travellers who can freely choose departure time and to travellers who use a scheduled service with fixed headway. Depending...... on parameters, travellers may be risk averse or risk seeking and the value of travel time may increase or decrease in the mean travel time....

The influence of continuous historical velocity difference information on micro-cooperative driving stability

Science.gov (United States)

Yang, Liang-Yi; Sun, Di-Hua; Zhao, Min; Cheng, Sen-Lin; Zhang, Geng; Liu, Hui

2018-03-01

In this paper, a new micro-cooperative driving car-following model is proposed to investigate the effect of continuous historical velocity difference information on traffic stability. The linear stability criterion of the new model is derived with linear stability theory and the results show that the unstable region in the headway-sensitivity space will be shrunk by taking the continuous historical velocity difference information into account. Through nonlinear analysis, the mKdV equation is derived to describe the traffic evolution behavior of the new model near the critical point. Via numerical simulations, the theoretical analysis results are verified and the results indicate that the continuous historical velocity difference information can enhance the stability of traffic flow in the micro-cooperative driving process.

Incineration of radioactive waste

International Nuclear Information System (INIS)

Eid, C.

1985-01-01

The incineration process currently seems the most appropriate way to solve the problems encountered by the increasing quantities of low and medium active waste from nuclear power generation waste. Although a large number of incinerators operate in the industry, there is still scope for the improvement of safety, throughput capacity and reduction of secondary waste. This seminar intends to give opportunity to scientists working on the different aspects of incineration to present their most salient results and to discuss the possibilities of making headway in the management of LL/ML radioactive waste. These proceedings include 17 contributions ranging over the subjects: incineration of solid β-γ wastes; incineration of other radwastes; measurement and control of wastes; off-gas filtration and release. (orig./G.J.P.)

Medium-range containerships making much headway%中型集装箱船大行其道

Institute of Scientific and Technical Information of China (English)

宋洋

2005-01-01

In the first 5 months of 2004, the transaction of the containerships worldwide continued maintaining a strong momentum. Among them, those medium-sized and small-sized containerships under 3000 TUE were clinched, totaling 85 units, up to 2.1 million dwt. These particular type of containerships have enjoyed substantial appreciation in the markets for reselling both the second-handed ships and new buildings since the second half of 2000. According to the statistics from the ship leasing market, the leasing rate for the medium-sized containerships has already topped its past records popped up in the third quarter of 2000. Likewise, the pricing of the small-and medium-sized containerships to be ordered has also exceeded its record high.

Implicit methods for equation-free analysis: convergence results and analysis of emergent waves in microscopic traffic models

DEFF Research Database (Denmark)

Marschler, Christian; Sieber, Jan; Berkemer, Rainer

2014-01-01

We introduce a general formulation for an implicit equation-free method in the setting of slow-fast systems. First, we give a rigorous convergence result for equation-free analysis showing that the implicitly defined coarse-level time stepper converges to the true dynamics on the slow manifold...... against the direction of traffic. Equation-free analysis enables us to investigate the behavior of the microscopic traffic model on a macroscopic level. The standard deviation of cars' headways is chosen as the macroscopic measure of the underlying dynamics such that traveling wave solutions correspond...... to equilibria on the macroscopic level in the equation-free setup. The collapse of the traffic jam to the free flow then corresponds to a saddle-node bifurcation of this macroscopic equilibrium. We continue this bifurcation in two parameters using equation-free analysis....

Desecularisation in Postcommunist Romania

Directory of Open Access Journals (Sweden)

KISS, Dénes

2015-03-01

Full Text Available The paper gives an analysis of the process as a result of which postcommunist Romania has moved from being an officially atheist country to being one of the most religious countries in Europe. Th e process of desecularisation is analysed in three dimensions. On the macro-level, I outline the religious headway in the most important institutions of the Romanian society, on the meso-level I analyse the changes in the organizational structure of churches and in the denominational structure of the country, while on the individual level the changes occurring in individual religiosity. In the fi nal part of the study I argue that within these dimensions desecularisation was realized to diff erent extents, while “desecularisation from above” is not likely to achieve its goals in the long run.

Development of ATC for High Speed and High Density Commuter Line

Science.gov (United States)

Okutani, Tamio; Nakamura, Nobuyuki; Araki, Hisato; Irie, Shouji; Osa, Hiroki; Sano, Minoru; Ikeda, Keigo; Ozawa, Hiroyuki

A new ATC (Automatic Train Control) system has been developed with solutions to realize short train headway by assured braking utilizing digital data transmission via rails; the digital data for the ATP (Automatic Train Protection) function; and to achieve EMC features for both AC and DC sections. The DC section is of the unprecedented DC traction power supply system utilizing IGBT PWM converter at all DC substations. Within the AC section, train traction force is controlled by PWM converter/inverters. The carrier frequencies of the digital data signals and chopping frequency of PWM traction power converters on-board are decided via spectral analysis of noise up to degraded mode cases of equipment. Developed system was equipped to the Tukuba Express Line, new commuter line of Tokyo metropolitan area, and opened since Aug. 2005.

Analysis of mixed traffic flow with human-driving and autonomous cars based on car-following model

Science.gov (United States)

Zhu, Wen-Xing; Zhang, H. M.

2018-04-01

We investigated the mixed traffic flow with human-driving and autonomous cars. A new mathematical model with adjustable sensitivity and smooth factor was proposed to describe the autonomous car's moving behavior in which smooth factor is used to balance the front and back headway in a flow. A lemma and a theorem were proved to support the stability criteria in traffic flow. A series of simulations were carried out to analyze the mixed traffic flow. The fundamental diagrams were obtained from the numerical simulation results. The varying sensitivity and smooth factor of autonomous cars affect traffic flux, which exhibits opposite varying tendency with increasing parameters before and after the critical density. Moreover, the sensitivity of sensors and smooth factors play an important role in stabilizing the mixed traffic flow and suppressing the traffic jam.

Analysing improvements to on-street public transport systems: a mesoscopic model approach

DEFF Research Database (Denmark)

Ingvardson, Jesper Bláfoss; Kornerup Jensen, Jonas; Nielsen, Otto Anker

2017-01-01

and other advanced public transport systems (APTS), the attractiveness of such systems depends heavily on their implementation. In the early planning stage it is advantageous to deploy simple and transparent models to evaluate possible ways of implementation. For this purpose, the present study develops...... headway time regularity and running time variability, i.e. taking into account waiting time and in-vehicle time. The approach was applied on a case study by assessing the effects of implementing segregated infrastructure and APTS elements, individually and in combination. The results showed...... that the reliability of on-street public transport operations mainly depends on APTS elements, and especially holding strategies, whereas pure infrastructure improvements induced travel time reductions. The results further suggested that synergy effects can be obtained by planning on-street public transport coherently...

Contribution to the improvement of heritage mural painting non-destructive testing by stimulated infrared thermography

Science.gov (United States)

Bodnar, Jean-Luc; Mouhoubi, Kamel; Di Pallo, Luigi; Detalle, Vincent; Vallet, Jean-Marc; Duvaut, Thierry

2013-10-01

Non-destructive testing of heritage mural paintings by means of stimulated infrared thermography has now become rather efficient [1-14]. However, pigments, which form a pictorial layer, have contrasting radiative properties possibly leading to artifact detection. In this paper, attempts to alleviate this difficulty are presented. Based on the spectroscopic study of different paint layers, one can argue that, in the medium infrared field, this radiative disparity decreases significantly. Then, with similar settings, it can be shown that ceramic radiative sources allow reaching this wavelength band. Finally, on the basis of a study carried out on an academic sample and a partial copy of a fresco from the cathedral of Angers, combining ceramic heat sources with a laboratory SAMMTHIR experimental setup enables to make real headway in terms of defects' detection.

Existing contradictions and problems in China's current economic and social development

Institute of Scientific and Technical Information of China (English)

Wang Tongsan

2014-01-01

Since the 18th National Congress of Communist Party of China (CPC),China has made important achievements and headway in economic and social development.However,now more than ever the focus should be on the conflicts and problems that continue to exist in China's economy.This paper examines six of them:(1) lack of a firm foundation for sustaining steady economic growth;(2) risks and hidden dangers in the financial,banking,and real estate sectors and massive overcapacity in some industries;(3) increasing difficulty in increasing agricultural production and raising rural incomes;(4) severe air,water,and soil pollution in certain regions and the arduous task of energy conservation and emissions reduction;(5) major structural problems constraining employment;and (6) issues of people's livelihood that have been the source of dissatisfaction for many Chinese citizens.

The logic of natural gas penetration in Europe

International Nuclear Information System (INIS)

Bernardet, C.

1992-01-01

This paper is trying first to bring out some characteristic lines from the thirty years period of natural gas market growth in Europe: triggering role of domestic gas resources, relay by imports, background from an existing manufactured gas industry. The different roles of bulk usages and scattered ones are underlined. Through an example it is showed that market conditions are relying on a rapid shift of the gas prices competitiveness and on the historical opportunity of space heating growth. In a second part, this paper analyses in each great sector of consumption that could sustain the growth to come of natural gas in Europe. This development relies on marketing forces and on the disposal of new usages for gas and new services for customers, with the benefit from technological headway. 8 figs

Outsourcing and supplier learning

DEFF Research Database (Denmark)

Lema, Rasmus

2012-01-01

that learning from customers was important but insufficient for making the transition. Capability formation depended significantly on other channels and mechanisms outside or independent of outsourcing relationships. This paper shows how firms actively mobilised and combined internal and external sources......There is increasing agreement that Indian software firms are making the transition from competitive advantage based on low cost to competitive advantage based on innovation. However, there are few insights about how this transition process works. This paper seeks to bring together the outsourcing......, global value chains and firm capability literatures. It draws on empirical material focused on learning and innovation ‘events’ in Indian software firms – their inputs and sources – and makes headway in opening the ‘black box’ of supplier learning in outsourcing relationships. This paper suggests...

.

Directory of Open Access Journals (Sweden)

Felipe Caleffi

2016-04-01

Full Text Available The main objective of this paper is to implement and test active traffic management (ATM strategies on a Brazilian freeway segment in order to assess and quantify the effectiveness of these strategies. Active traffic management dynamically manages traffic flow based on existing traffic conditions. Simulation software VISSIM was used to evaluate the simulated ATM strategies, and was calibrated to reflect the freeway driver’s behavior. Simulated ATM strategies were speed harmonization and temporary use of hard shoulders. The results showed that active traffic management has a positive impact on traffic operation and benefits of the modeled strategies included: shorter headways, reduction in travel times, reduction in travel time variability and reduction in number of lane changes. Tested strategies also reduced the duration of congestion, increasing the efficiency of the segment under analysis.

Assessing the Influence of Political Parties on Public Opinion: The Challenge from Pretreatment Effects

DEFF Research Database (Denmark)

Slothuus, Rune

2016-01-01

Despite generations of research, political scientists have trouble pinpointing the influence of political parties on public opinion. Recently, scholars have made headway in exploring whether parties in fact shape policy preferences by relying on experimental designs. Yet, the evidence from...... this work is mixed. I argue that the typical experiment faces a design problem that likely minimizes the extent to which parties apparently matter. Because parties have policy reputations, experimental participants may already know from real-world exposure to political debate where the parties stand before...... they are told in the experiment—they are “pretreated.” This study investigates how real-world political context interferes with party cue stimulus in experiments. In two experiments I show that two types of “pretreatment” from outside the experiment—exposure-based and reputation-based—dramatically moderate...

The impact of scheduling on service reliability : Trip-time determination and holding points in long-headway services

NARCIS (Netherlands)

Van Oort, N.; Boterman, J.W.; Van Nes, R.

2012-01-01

This paper presents research on optimizing service reliability of longheadway services in urban public transport. Setting the driving time, and thus the departure time at stops, is an important decision when optimizing reliability in urban public transport. The choice of the percentile out of

Evolving perspectives of the role of novel agents in androgen-independent prostate cancer

Directory of Open Access Journals (Sweden)

Sujith Kalmadi

2008-01-01

Full Text Available Metastatic androgen-independent prostate cancer presents an intriguing clinical challenge, with a subtle interaction between hormone-responsive and refractory tumor cell elements. The treatment of advanced prostate carcinoma, which had remained stagnant for several decades following the understanding of the link between androgenic stimulation and carcinogenesis, has now started to make steady headway with chemotherapy and targeted approaches. Metastatic prostate cancer is almost always treated with initial androgen deprivation, in various forms. However, despite such treatment androgen-independent prostate cancer cells eventually emerge and progress to threaten life. The therapeutic objectives for treatment of metastatic prostate cancer are to maintain the quality of life and prolong survival. The out-dated nihilistic dogma of deferring chemotherapy until the most advanced stages in advanced prostate cancer is now falling by the wayside with the development of newer effective, tolerable agents.

Modeling and evaluation of characteristics for on-street Rapid Transit systems

DEFF Research Database (Denmark)

Andersen, Jonas Lohmann Elkjær; Landex, Alex

2012-01-01

to obtain the main objective of introducing a Rapid Transit System. to increase the number of passengers. Variations in the system characteristics have a direct impact on ridership. However, it is difficult to predict the impact of implementing or altering the characteristics. A Rapid Transit system should...... display sufficient service already in the planning phase. That is why pre-acquired knowledge of the impact of the characteristics on the system performance is valuable. Such knowledge could provide a firm basis for planning the service and operation of a Rapid Transit system. This article focuses....... It focuses on the following characteristics for Rapid Transit systems: rail factor, travel time, headway and capacity. It evaluates how the implementation and variation of these characteristics affected the ridership of a case project. It evaluates the magnitude of the impacts for the various characteristics...

A Fuzzy Optimization Model for High-Speed Railway Timetable Rescheduling

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Li Wang

2012-01-01

Full Text Available A fuzzy optimization model based on improved symmetric tolerance approach is introduced, which allows for rescheduling high-speed railway timetable under unexpected interferences. The model nests different parameters of the soft constraints with uncertainty margin to describe their importance to the optimization purpose and treats the objective in the same manner. Thus a new optimal instrument is expected to achieve a new timetable subject to little slack of constraints. The section between Nanjing and Shanghai, which is the busiest, of Beijing-Shanghai high-speed rail line in China is used as the simulated measurement. The fuzzy optimization model provides an accurate approximation on train running time and headway time, and hence the results suggest that the number of seriously impacted trains and total delay time can be reduced significantly subject to little cost and risk.

Complex behavior of elevators in peak traffic

Science.gov (United States)

Nagatani, Takashi

2003-08-01

We study the dynamical behavior of elevators in the morning peak traffic. We present a stochastic model of the elevators to take into account the interactions between elevators through passengers. The dynamics of the elevators is expressed in terms of a coupled nonlinear map with noises. The number of passengers carried by an elevator and the time-headway between elevators exhibit the complex behavior with varying elevator trips. It is found that the behavior of elevators exhibits a deterministic chaos even if there are no noises. The chaotic motion depends on the loading parameter, the maximum capacity of an elevator, and the number of elevators. When the loading parameter is superior to the threshold, each elevator carries a full load of passengers throughout its trip. The dependence of the threshold (transition point) on the elevator capacity is clarified.

Jam Formation of Traffic Flow in Harbor Tunnel

International Nuclear Information System (INIS)

He Hongdi; Lu Weizhen; Dong Liyun

2011-01-01

This paper reports a study concerning occurrence and growth of traffic jam in a harbor tunnel. The single-lane with three sections (downgrade, flat, and upgrade) is taken into account and they are characterized with different velocity limit. At the low density, the traffic current increases linearly with density and saturates at some values of immediately density. As the density increases, the traffic jam appears firstly before the upgrade section and then extends to the downgrade section. Additionally, the relationships of the velocity and headway against position in different densities are obtained from simulation. These results clearly clarify where and when the traffic jam appears. Finally, the critical densities are derived via the theoretical analysis before and after the discontinuous fronts and the theoretical results are consistent with the critical values of simulation results. (interdisciplinary physics and related areas of science and technology)

Exploring the Impact of Commuter’s Residential Location Choice on the Design of a Rail Transit Line Based on Prospect Theory

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Ding Liu

2014-01-01

Full Text Available This paper explores the impact of prospect theory based commuter’s residential location choice on the design problem of a rail transit line located in a monocentric city. A closed-form social welfare maximization model is proposed, with special consideration given to prospect theory based commuter’s residential location choice over years. Commuters are assumed to make residential location choice by a trade-off between daily housing rent and generalized travel cost to minimize their prospect values. The solutions properties of the proposed model are explored and compared analytically. It is found that overestimation exists for the optimal solutions of rail line length, headway, and fare based on traditional utility theory, compared with the optimal solutions of the proposed prospect theory based model. A numerical example is given to illustrate the properties of the proposed model.

Effects of Countdown Signals in Red Phase on Drivers: A Comparative Study between Japan and Turkey

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Ke Yu

2014-01-01

Full Text Available Countdown signals can be found in many countries; however, there are only a few researches that study the impact of the signals on driver behavior. In this study, we focus particularly on the behavior of drivers reacting to countdown signals when the signal shifted from red to green. Although the countdown signal can reduce startup delay, it also causes drivers premature start. This paper determines the factors influencing the behaviors of drivers on startup delay, premature start, and headway due to countdown signals. The analysis results are compared between Japan and Turkey. From our findings, we propose countermeasures to reduce the problems caused by the countdown signals which can be a guideline for implementation or modification of countdown-signalized intersections in many countries in order to increase safety of both drivers and pedestrians as well as drivers’ satisfactions.

Lane-changing behavior and its effect on energy dissipation using full velocity difference model

Science.gov (United States)

Wang, Jian; Ding, Jian-Xun; Shi, Qin; Kühne, Reinhart D.

2016-07-01

In real urban traffic, roadways are usually multilane with lane-specific velocity limits. Most previous researches are derived from single-lane car-following theory which in the past years has been extensively investigated and applied. In this paper, we extend the continuous single-lane car-following model (full velocity difference model) to simulate the three-lane-changing behavior on an urban roadway which consists of three lanes. To meet incentive and security requirements, a comprehensive lane-changing rule set is constructed, taking safety distance and velocity difference into consideration and setting lane-specific speed restriction for each lane. We also investigate the effect of lane-changing behavior on distribution of cars, velocity, headway, fundamental diagram of traffic and energy dissipation. Simulation results have demonstrated asymmetric lane-changing “attraction” on changeable lane-specific speed-limited roadway, which leads to dramatically increasing energy dissipation.

Electric Vehicle Scenarios for India: Implications for mitigation and development

DEFF Research Database (Denmark)

Shukla, P.R.; Dhar, Subash; Bhaskar, Kalyan

2014-01-01

to infrastructure and policies. While the literature on EVs has focused more on the role of electric cars, it could be electric two-wheelers which could make early headway, as is the case in China where nearly 120 million such vehicles had been sold by the end of 2012. Three scenarios (Business as Usual (BAU......The transport sector globally is overly dependent on liquid fossil fuels. Electric vehicles (EVs) are touted as a way of diversifying the fuel mix and helping to reduce dependence on fossil fuels. There could also be other co-benefits of EVs, such as improved energy security, decarbonising...... of the electricity sector, CO2 mitigation and reduction in local air pollution. The Indian government has recently launched a national electricity mobility mission to promote EVs. There is, however, much uncertainty in terms of the penetration of EVs in the transport sector, particularly those related...

Survey of heat-pipe application under nuclear environment

International Nuclear Information System (INIS)

Tsuyuzaki, Noriyoshi; Saito, Takashi; Okamoto, Yoshizo; Hishida, Makoto; Negishi, Kanji.

1986-11-01

Heat pipes today are employed in a wide variety of special heat transfer applications including nuclear reactor. In this nuclear technology area in Japan, A headway speed of the heat pipe application technique is not so high because of safety confirmation and investigation under each developing step. Especially, the outline of space craft is a tendency to increase the size. Therefore, the power supply is also tendency to increase the outlet power and keep the long life. Under SP-100 project, the development of nuclear power supply system which power is 1400 - 1600 KW thermal and 100 KW electric power is steadily in progress. Many heat pipes are adopted for thermionic conversion and coolant system in order to construct more safety and light weight system for the project. This paper describes the survey of the heat pipe applications under the present and future condition for nuclear environment. (author)

Station Model for Rail Transit System Using Cellular Automata

International Nuclear Information System (INIS)

Xun Jing; Ning Bin; Li Keping

2009-01-01

In this paper, we propose a new cellular automata model to simulate the railway traffic at station. Based on NaSch model, the proposed station model is composed of the main track and the siding track. Two different schemes for trains passing through station are considered. One is the scheme of 'pass by the main track, start and stop by the siding track'. The other is the scheme of 'two tracks play the same role'. We simulate the train movement using the proposed model and analyze the traffic flow at station. The simulation results demonstrate that the proposed cellular automata model can be successfully used for the simulations of railway traffic. Some characteristic behaviors of railway traffic flow can be reproduced. Moreover, the simulation values of the minimum headway are close to the theoretical values. This result demonstrates the dependability and availability of the proposed model. (general)

Nonlinear dynamics of autonomous vehicles with limits on acceleration

Science.gov (United States)

Davis, L. C.

2014-07-01

The stability of autonomous vehicle platoons with limits on acceleration and deceleration is determined. If the leading-vehicle acceleration remains within the limits, all vehicles in the platoon remain within the limits when the relative-velocity feedback coefficient is equal to the headway time constant [k=1/h]. Furthermore, if the sensitivity α>1/h, no collisions occur. String stability for small perturbations is assumed and the initial condition is taken as the equilibrium state. Other values of k and α that give stability with no collisions are found from simulations. For vehicles with non-negligible mechanical response, simulations indicate that the acceleration-feedback-control gain might have to be dynamically adjusted to obtain optimal performance as the response time changes with engine speed. Stability is demonstrated for some perturbations that cause initial acceleration or deceleration greater than the limits, yet do not cause collisions.

Station Capacity

DEFF Research Database (Denmark)

Landex, Alex

2011-01-01

the probability of conflicts and the minimum headway times into account. The last method analyzes how optimal platform tracks are used by examining the arrival and departure pattern of the trains. The developed methods can either be used separately to analyze specific characteristics of the capacity of a station......Stations are often limiting the capacity of railway networks. This is due to extra need of tracks when trains stand still, trains turning around, and conflicting train routes. Although stations are often the capacity bottlenecks, most capacity analysis methods focus on open line capacity. Therefore...... for platform tracks and the probability that arriving trains will not get a platform track immediately at arrival. The third method is a scalable method that analyzes the conflicts in the switch zone(s). In its simplest stage, the method just analyzes the track layout while the more advanced stages also take...

Neural Adaptive Sliding-Mode Control of a Vehicle Platoon Using Output Feedback

Directory of Open Access Journals (Sweden)

Maode Yan

2017-11-01

Full Text Available This paper investigates the output feedback control problem of a vehicle platoon with a constant time headway (CTH policy, where each vehicle can communicate with its consecutive vehicles. Firstly, based on the integrated-sliding-mode (ISM technique, a neural adaptive sliding-mode control algorithm is developed to ensure that the vehicle platoon is moving with the CTH policy and full state measurement. Then, to further decrease the measurement complexity and reduce the communication load, an output feedback control protocol is proposed with only position information, in which a higher order sliding-mode observer is designed to estimate the other required information (velocities and accelerations. In order to avoid collisions among the vehicles, the string stability of the whole vehicle platoon is proven through the stability theorem. Finally, numerical simulation results are provided to verify its effectiveness and advantages over the traditional sliding-mode control method in vehicle platoons.

Highly integrated image sensors enable low-cost imaging systems

Science.gov (United States)

Gallagher, Paul K.; Lake, Don; Chalmers, David; Hurwitz, J. E. D.

1997-09-01

The highest barriers to wide scale implementation of vision systems have been cost. This is closely followed by the level of difficulty of putting a complete imaging system together. As anyone who has every been in the position of creating a vision system knows, the various bits and pieces supplied by the many vendors are not under any type of standardization control. In short, unless you are an expert in imaging, electrical interfacing, computers, digital signal processing, and high speed storage techniques, you will likely spend more money trying to do it yourself rather than to buy the exceedingly expensive systems available. Another alternative is making headway into the imaging market however. The growing investment in highly integrated CMOS based imagers is addressing both the cost and the system integration difficulties. This paper discusses the benefits gained from CMOS based imaging, and how these benefits are already being applied.

Synchronized flow in oversaturated city traffic.

Science.gov (United States)

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

2013-11-01

Based on numerical simulations with a stochastic three-phase traffic flow model, we reveal that moving queues (moving jams) in oversaturated city traffic dissolve at some distance upstream of the traffic signal while transforming into synchronized flow. It is found that, as in highway traffic [Kerner, Phys. Rev. E 85, 036110 (2012)], such a jam-absorption effect in city traffic is explained by a strong driver's speed adaptation: Time headways (space gaps) between vehicles increase upstream of a moving queue (moving jam), resulting in moving queue dissolution. It turns out that at given traffic signal parameters, the stronger the speed adaptation effect, the shorter the mean distance between the signal location and the road location at which moving queues dissolve fully and oversaturated traffic consists of synchronized flow only. A comparison of the synchronized flow in city traffic found in this Brief Report with synchronized flow in highway traffic is made.

Recent Developments in Carbonylation Chemistry Using [13 C]CO, [11 C]CO and [14 C]CO.

Science.gov (United States)

Nielsen, Dennis U; Neumann, Karoline T; Lindhardt, Anders T; Skrydstrup, Troels

2018-06-01

Carbon monoxide represents the most important C1-building block for the chemical industry, both for the production of bulk and fine chemicals, but also for synthetic fuels. Yet, its toxicity and subsequently its cautious handling has limited its applications in medicinal chemistry research and in particular for the synthesis of pharmaceutically relevant molecules. Recent years have nevertheless witnessed a considerable headway on the development of carbon monoxide surrogates and reactor systems, which provide an ideal setting for performing carbonylation chemistry with stoichiometric and sub-stoichiometric carbon monoxide. Such set-ups are particularly ideal for the introduction of isotope labels such as carbon-11, carbon-13 and carbon-14 into bioactive compounds. This review summarizes this growing field and examines the large number of carbonylation reactions that can be exploited for the introduction of a carbon isotope. This article is protected by copyright. All rights reserved.

Reducing behavioural risk factors for cancer: An affect regulation perspective.

Science.gov (United States)

O'Leary, Daniel; Suri, Gaurav; Gross, James J

2018-01-01

Nearly half of all cancer deaths are attributable to preventable causes, primarily unhealthy behaviours such as tobacco use, alcohol use and overeating. In this review, we argue that people engage in these behaviours, at least in part, as a means of regulating their affective states. To better understand why people engage in these behaviours and how researchers might design interventions to promote the selection of healthier methods for regulating affect, we propose a conceptual model of affect regulation. We synthesise research from both the stress and coping tradition as well as the emotion and emotion regulation tradition, two literatures that are not typically integrated. In so doing, we indicate where researchers have made headway in understanding these behaviours as affect regulation and note how our model could be used to structure future work in a way that would be particularly advantageous to cancer control efforts.

From Internationalism to Internationalisation: The Illusion of a Global Community in Higher Education

Directory of Open Access Journals (Sweden)

Graham Pike

2012-09-01

Full Text Available Both global education and international education are movements designedto promote the concepts of internationalism and global community innational education systems, but with different histories. While the former, agrassroots K-12 movement, has struggled to make headway against theforces of neoliberalism, the latter has thrived in a market-driven era inwhich revenue from international student mobility has offset decliningpublic funding of higher education in many developed countries. Currenttrends in the internationalisation of higher education have resulted inincreasing commercialisation and intensive competition for internationalstudents, fuelled by world rankings of elite universities. Tensions existbetween these trends and the more altruistic goals of internationaleducation proclaimed in institutional mission statements and governmentpolicies. An analytical matrix is offered as a tool with which highereducation institutions can map their internationalisation activities andassess the extent to which they match their stated policies and missions.While the rhetoric of international education purports to promote theconcept of a global community, the article suggests this claim may beillusory.

Health technology assessment and health policy today a multifaceted view of their unstable crossroads

CERN Document Server

del Llano-Señarís, Juan E

2015-01-01

This book disentangles the issues in connection with the advancement of Health Technology Assessment (HTA) and its interface with health policy. It highlights the factors that should shape its progress in the near future. Interdisciplinary and critical views from a number of professionals are put together in a prescient order to cast some light and make recommendations as to the next steps HTA should take to be fit for purpose. A wealth of documents dealing with HTA have been published over the last three decades. HTA allegedly is one of the bedrocks of regulation and medical decision making. However, counter vailing visions contend that geographical variations in the role that HTA is actually playing within countries pinpoints specific room for improvement. Given our social preferences, cherry-picking HTA's features and successes over the last decades moves it away from its possibility frontier. Some of the most noteworthy hindrances that HTA faces, in several countries, to making headway towards its consoli...

Developments for medium-capacity urban public transport

Energy Technology Data Exchange (ETDEWEB)

Calverley, H B

1979-11-01

Light guideway transit (LGT), that is, automatically operated urban electric vehicles carrying 12 to 70 passengers via elevated guideways or underground tunnels, with stations 250 to 800 meters apart, and self-contained during off hours as regards propulsion and control, could help relieve future energy demands. Over 30 LGT systems are currently under development, and their various mechanical, electrical, and power-source (three-phase distribution, thyristor phase-angle control and dc rotating motors) aspects are presented. Developments in present-day trolleys, battery buses (lead-acid, alkaline), combustion-engined buses, and hybrid vehicles are reviewed, with particular emphasis on energy, such as its mechanical storage by flywheels during regenerative braking. Specific requirements of future LGT systems, including vehicle support systems (by magnetic levitation using dc magnets, air support by either cushion or suction, pneumatic tires, steel wheels, or above-ground suspension), headway and line capacity, junction switching, and automatic vehicle control are discussed.

Global environmental policy strategies. ''Environment and development'' in north-south relations. Strategien globaler Umweltpolitik. ''Umwelt und Entwicklung'' in den Nord-Sued-Beziehungen

Energy Technology Data Exchange (ETDEWEB)

Bruckmeier, K

1994-01-01

Global environmental policy has hardly made headway after the United Nations World Conference on Environment and Development (UNCED) in Rio in June 1992, despite there being no shortage of programmes, institutions, and actors. Obviously, formal structures for political action based on the system of institutions of the United Nations do not suffice. Global environmental policy strategies must reach further, overcoming system-immanent obstacles to sustainable development. This necessitates analyzing the causes of environmental destruction and making a critical evaluation of the relations between the societies of the North and South that received their imprint from development policies. Only after such a preliminary elucidation by interdisciplinary approaches in the light of political and ecological economy and human ecology does an empirical analysis of politically controlled processes in environmental and development policy make sense. The analysis points to strategies for this international political field that rely on non-governmental actors and social movements, and question the traditional European model of an environmental policy determined by government institutions. (orig./UA)

The Contribution to the Procedure of Capacity Determination at Unsignalized Priority-controlled Intersections

Directory of Open Access Journals (Sweden)

Tomaž Tolazzi

2004-01-01

Full Text Available The problem of minor vehicles crossing or merging into themajor stream at unsignalized priority-controlled intersections iswell-known. Numerous solutions involve various assumptionsconcerning the major headway distributions, number of majorlanes, critical gap distributions, etc. Such cases can be dividedinto two main groups: intersections with two streams (one majorand one minor stream and intersections with more thantwo streams (more than one major stream and one minorstream. At roundabouts, also at single-lane roundabouts,there are similar problems like the ones at other unsignalizedpriority-controlled intersections. A vehicle at the roundaboutapproach can only cross the pedestrian crossing when a sufficienttime-gap between two pedestrians (or cyclists is provided.A vehicle at the roundabout entries can only merge into the majorstream when a sufficient gap between the two vehicles in themajor stream is provided. Because of that, single-lane roundaboutscan also be treated as unsignalized intersections withtwo major lanes: the first one in its circulatory roadway and thesecond one on the pedestrian crossing.

PASSENGER CAR EQUIVALENT (PCE OF THROUGH VEHICLES AT SIGNALIZED INTERSECTIONS IN DHAKA METROPOLITAN CITY, BANGLADESH

Directory of Open Access Journals (Sweden)

Partha SAHA

2009-01-01

PCE currently used in Bangladesh is based on the values given in Geometric Design of Highways (MoC, 2001, which is the modification of the values given by Webster (1958 on the study performed in the United Kingdom in the 50's and 60's. But now-a-days, the situation is far different both for traffic and road user as the characteristics have changed from that time. Hence, in this paper an empirical study was carried out to determine the PCE of different types of vehicle that reflect the actual traffic conditions of Dhaka Metropolitan City. Data were collected from ten signalized intersections and the headway ratio method was used to estimate the PCE of different types of vehicle. The main vehicle compositions observed during the study period consist of passenger cars, auto-rickshaws, mini-buses and buses. The PCE obtained in this study were compared to the values established earlier. It was found that the estimated PCE are smaller than those being used in Bangladesh.

New technological design of arithmetics

International Nuclear Information System (INIS)

Hanitriarivo, R.

2008-01-01

There are illogical and irrational rules in numbers writing and pronunciation in almost of languages. A part of the aim is to show the electronic applications possibility of logical and systematic rules which are proposed by Raoelina Andriambololona to write and pronounce numbers; we had studied and created the arithmetic operations representation corresponding in binary basis and in hexadecimal basis. The brand new found concept corresponds as well as the method which uses the matrix product calculation, in according with the writing and the pronunciation of numbers. It was shown how to concept the arithmetic operators in digital electronics; and we proposed and assumed to make headway and to do amelioration for technical conception of calculator and arithmetic unite those are at the basic function of all computers and almost domestic sophisticated machine. The left hand side- right hand side and increasing order writing of number is exploited to build a new computer programming for a scientific calculator. [fr

Aquaculture as yet another environmental gateway to the development and globalisation of antimicrobial resistance.

Science.gov (United States)

Cabello, Felipe C; Godfrey, Henry P; Buschmann, Alejandro H; Dölz, Humberto J

2016-07-01

Aquaculture uses hundreds of tonnes of antimicrobials annually to prevent and treat bacterial infection. The passage of these antimicrobials into the aquatic environment selects for resistant bacteria and resistance genes and stimulates bacterial mutation, recombination, and horizontal gene transfer. The potential bridging of aquatic and human pathogen resistomes leads to emergence of new antimicrobial-resistant bacteria and global dissemination of them and their antimicrobial resistance genes into animal and human populations. Efforts to prevent antimicrobial overuse in aquaculture must include education of all stakeholders about its detrimental effects on the health of fish, human beings, and the aquatic ecosystem (the notion of One Health), and encouragement of environmentally friendly measures of disease prevention, including vaccines, probiotics, and bacteriophages. Adoption of these measures is a crucial supplement to efforts dealing with antimicrobial resistance by developing new therapeutic agents, if headway is to be made against the increasing problem of antimicrobial resistance in human and veterinary medicine. Copyright © 2016 Elsevier Ltd. All rights reserved.

Traffic signs recognition for driving assistance

Science.gov (United States)

Sai Sangram Reddy, Yatham; Karthik, Devareddy; Rana, Nikunj; Jasmine Pemeena Priyadarsini, M.; Rajini, G. K.; Naseera, Shaik

2017-11-01

In the current circumstances with the innovative headway, we must be able to provide assistance to the driving in recognising the traffic signs on the roads. At present time, many reviews are being directed moving in the direction of the usage of a keen Traffic Systems. One field of this exploration is driving support systems, and many reviews are being directed to create frameworks which distinguish and perceive street signs in front of the vehicle, and afterward utilize the data to advise the driver or to even control the vehicle by implementing this system on self-driving vehicles. In this paper we propose a method to detect the traffic sign board in a frame using HAAR cascading and then identifying the sign on it. The output may be either given out in voice or can be displayed as per the driver’s convenience. Each of the Traffic Sign is recognised using a database of images of symbols used to train the KNN classifier using open CV libraries.

Absence of jamming in ant trails: feedback control of self-propulsion and noise.

Science.gov (United States)

Chaudhuri, Debasish; Nagar, Apoorva

2015-01-01

We present a model of ant traffic considering individual ants as self-propelled particles undergoing single-file motion on a one-dimensional trail. Recent experiments on unidirectional ant traffic in well-formed natural trails showed that the collective velocity of ants remains approximately unchanged, leading to the absence of jamming even at very high densities [John et al., Phys. Rev. Lett. 102, 108001 (2009)]. Assuming a feedback control mechanism of self-propulsion force generated by each ant using information about the distance from the ant in front, our model captures all the main features observed in the experiment. The distance headway distribution shows a maximum corresponding to separations within clusters. The position of this maximum remains independent of average number density. We find a non-equilibrium first-order transition, with the formation of an infinite cluster at a threshold density where all the ants in the system suddenly become part of a single cluster.

The new linguistic order

Directory of Open Access Journals (Sweden)

Joshua A. Fishman

2001-07-01

Full Text Available The globalisation phenomenon that we are currently seeing has lead to major linguistic changes on a worldwide scale. English has become the leading international language, in economic and political spheres, and is becoming the language of high society and of the young. At the same time, however, regional languages are also making considerable headway, thanks to new social interaction and economic backing from their governments. In turn, and as a result of these two trends, there is impetus for feelings of belonging to local communities which see their language as a sign of their own authenticity, one that has to be defended against the phenomena of globalisation and regionalisation. We are thus heading towards a multilingual society, in which each language has its own, distinct social functions, even though it is inevitable that there will be conflict between the languages that come into contact. In this scenario, the author predicts a loss of hegemony for English, in favour of regional languages, and the future extinction of the least spoken minority languages.

Setting the bar: Standards for ecosystem services.

Science.gov (United States)

Polasky, Stephen; Tallis, Heather; Reyers, Belinda

2015-06-16

Progress in ecosystem service science has been rapid, and there is now a healthy appetite among key public and private sector decision makers for this science. However, changing policy and management is a long-term project, one that raises a number of specific practical challenges. One impediment to broad adoption of ecosystem service information is the lack of standards that define terminology, acceptable data and methods, and reporting requirements. Ecosystem service standards should be tailored to specific use contexts, such as national income and wealth accounts, corporate sustainability reporting, land-use planning, and environmental impact assessments. Many standard-setting organizations already exist, and the research community will make the most headway toward rapid uptake of ecosystem service science by working directly with these organizations. Progress has been made in aligning with existing organizations in areas such as product certification and sustainability reporting, but a major challenge remains in mainstreaming ecosystem service information into core public and private use contexts, such as agricultural and energy subsidy design, national income accounts, and corporate accounts.

Cross-Domain Analogies as Relating Derived Relations among Two Separate Relational Networks

Science.gov (United States)

Ruiz, Francisco J; Luciano, Carmen

2011-01-01

Contemporary behavior analytic research is making headway in analyzing analogy as the establishment of a relation of coordination among common types of trained or derived relations. Previous studies have been focused on within-domain analogy. The current study expands previous research by analyzing cross-domain analogy as relating relations among separate relational networks and by correlating participants' performance with a standard measure of analogical reasoning. In two experiments, adult participants first completed general intelligence and analogical reasoning tests. Subsequently, they were exposed to a computerized conditional discrimination training procedure designed to create two relational networks, each consisting of two 3-member equivalence classes. The critical test was a two-part analogical test in which participants had to relate combinatorial relations of coordination and distinction between the two relational networks. In Experiment 1, combinatorial relations for each network were individually tested prior to analogical testing, but in Experiment 2 they were not. Across both experiments, 65% of participants passed the analogical test on the first attempt. Moreover, results from the training procedure were strongly correlated with the standard measure of analogical reasoning. PMID:21547072

The Research of Car-Following Model Based on Real-Time Maximum Deceleration

Directory of Open Access Journals (Sweden)

Longhai Yang

2015-01-01

Full Text Available This paper is concerned with the effect of real-time maximum deceleration in car-following. The real-time maximum acceleration is estimated with vehicle dynamics. It is known that an intelligent driver model (IDM can control adaptive cruise control (ACC well. The disadvantages of IDM at high and constant speed are analyzed. A new car-following model which is applied to ACC is established accordingly to modify the desired minimum gap and structure of the IDM. We simulated the new car-following model and IDM under two different kinds of road conditions. In the first, the vehicles drive on a single road, taking dry asphalt road as the example in this paper. In the second, vehicles drive onto a different road, and this paper analyzed the situation in which vehicles drive from a dry asphalt road onto an icy road. From the simulation, we found that the new car-following model can not only ensure driving security and comfort but also control the steady driving of the vehicle with a smaller time headway than IDM.

Control over surrounding rocks deformation of soft floor and whole-coal gateways with trapezoidal supports

Energy Technology Data Exchange (ETDEWEB)

Zhai, X.; Li, D.; Shao, Q.; Sun, Y. [Henan Polytechnic University, Jaozuo (China). Dept. of Resource and Material Engineering

2005-06-01

The coal seams of Guengcun Coal mine of Yima Coal Group Co. Ltd. are prone to spontaneous combustion. Fully mechanized longwall mining with sublevel caving is used as the mining method. Based on the characteristics of the gateways of the 1301 coal face and of the roof coal seams, the natural equilibrium arch theory was used to design the parameters of 11 mine-type metal supports. Then, in-situ supporting experiments were carried out. The results indicate that under the action of virgin rock stress, the width of broken rocks zone of surrounding rocks is 1.7-2.0 m in the return heading and 1.1-1.3 m in the outgoing headway and their surrounding rocks belong to the IV-type soft rock and the III-type common surrounding rock respectively. Therefore, under the movable abutment pressure, the gateway deformation is serious. At the same time, the accumulated water on gateway floor must be drained in time. These measures were taken in the 1302 and 1304 coal faces in Gengcun colliery, and satisfactory results have been obtained. 8 refs., 3 figs.

After the double helix: Rosalind Franklin's research on Tobacco mosaic virus.

Science.gov (United States)

Creager, Angela N H; Morgan, Gregory J

2008-06-01

Rosalind Franklin is best known for her informative X-ray diffraction patterns of DNA that provided vital clues for James Watson and Francis Crick's double-stranded helical model. Her scientific career did not end when she left the DNA work at King's College, however. In 1953 Franklin moved to J. D. Bernal's crystallography laboratory at Birkbeck College, where she shifted her focus to the three-dimensional structure of viruses, obtaining diffraction patterns of Tobacco mosaic virus (TMV) of unprecedented detail and clarity. During the next five years, while making significant headway on the structural determination of TMV, Franklin maintained an active correspondence with both Watson and Crick, who were also studying aspects of virus structure. Developments in TMV research during the 1950s illustrate the connections in the emerging field of molecular biology between structural studies of nucleic acids and of proteins and viruses. They also reveal how the protagonists of the "race for the double helix" continued to interact personally and professionally during the years when Watson and Crick's model for the double-helical structure of DNA was debated and confirmed.

Miriti artifacts (Mauritia flexuosa L. f. in Abaetetuba, Pará State, Brazil: from production to marketing

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Ronize da Silva Santos

2011-12-01

Full Text Available The palm tree Mauritia flexuosa L. f. (Miriti provides the raw materials to basketry and toys, with economic and cultural significance to Amazon estuary communities. This paper surveyed the production and marketing of panniers and miriti toys in Abaetetuba, State of Pará, Brazil. The research was conducted in the riverine hamlet of Cutininga and in two craftsmen associations of Abaetetuba city, with semi-structured and non-structured interviews, totalizing 18 informants. Among marketed basketry items, panniers were the only products consistently sold, providing a steady flow of income for the residents of Cutininga. The commercialization of miriti toys has made increasing headway each year, with peak production and sales during October, on the occasion of the religious festival of the Círio de Nossa Senhora de Nazaré. Both toys and panniers have made their mark in the commercialization of craftwork. The miriti toys, made from Mauritia flexuosa L. f. fronds, have higher economic value for the county of Abaetetuba as a whole. Yet, for the community of Cutininga, panniers have a higher marketing value.

Channel crossing: how are proteins shipped across the bacterial plasma membrane?

Science.gov (United States)

Collinson, Ian; Corey, Robin A; Allen, William J

2015-10-05

The structure of the first protein-conducting channel was determined more than a decade ago. Today, we are still puzzled by the outstanding problem of protein translocation--the dynamic mechanism underlying the consignment of proteins across and into membranes. This review is an attempt to summarize and understand the energy transducing capabilities of protein-translocating machines, with emphasis on bacterial systems: how polypeptides make headway against the lipid bilayer and how the process is coupled to the free energy associated with ATP hydrolysis and the transmembrane protein motive force. In order to explore how cargo is driven across the membrane, the known structures of the protein-translocation machines are set out against the background of the historic literature, and in the light of experiments conducted in their wake. The paper will focus on the bacterial general secretory (Sec) pathway (SecY-complex), and its eukaryotic counterpart (Sec61-complex), which ferry proteins across the membrane in an unfolded state, as well as the unrelated Tat system that assembles bespoke channels for the export of folded proteins. © 2015 The Authors.

The effects of using a portable music player on simulated driving performance and task-sharing strategies.

Science.gov (United States)

Young, Kristie L; Mitsopoulos-Rubens, Eve; Rudin-Brown, Christina M; Lenné, Michael G

2012-07-01

This study examined the effects of performing scrollable music selection tasks using a portable music player (iPod Touch™) on simulated driving performance and task-sharing strategies, as evidenced through eye glance behaviour and secondary task performance. A total of 37 drivers (18-48 yrs) completed the PC-based MUARC Driver Distraction Test (DDT) while performing music selection tasks on an iPod Touch. Drivers' eye glance behaviour was examined using faceLAB eye tracking equipment. Results revealed that performing music search tasks while driving increased the amount of time that drivers spent with their eyes off the roadway and decreased their ability to maintain a constant lane position and time headway from a lead vehicle. There was also evidence, however, that drivers attempted to regulate their behaviour when distracted by decreasing their speed and taking a large number of short glances towards the device. Overall, results suggest that performing music search tasks while driving is problematic and steps to prohibit this activity should be taken. Copyright © 2011 Elsevier Ltd and The Ergonomics Society. All rights reserved.

The Asian Values in Singapore`s Context of Use. The Curbsides of the Singapore`s Model of Democracy

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Bianca Berna

2013-11-01

Full Text Available Out of a sense of nationhood or out of mere circumstantial and specific relatings to a national context, it is altogether visible that anti-universalist debate is making headway in international relations, in cultural studies and in the political science, if we are to classify a broader consultation of events.This article is aimed at presenting how the Western ideas can be seen, in examination, as artificial structures, in the national context of Asia. The Asian Values are a very interesting evaluative specimen of the anti-universalist orations. In the case of many Asian states, they created settled forms of government, having an especial adaptation with the originating incidents that were their birthplace. With the inward of these units of contextualization, we will turn to the conferral of the Singapore democracy model and to its germane bloc and bond with the Asian Values. We will interrelate a personal conspectus regarding the correctness of the seal of fastening between the Asian Values and Singapore`s democracy model.

Cellular automata model for traffic flow with safe driving conditions

International Nuclear Information System (INIS)

Lárraga María Elena; Alvarez-Icaza Luis

2014-01-01

In this paper, a recently introduced cellular automata (CA) model is used for a statistical analysis of the inner microscopic structure of synchronized traffic flow. The analysis focuses on the formation and dissolution of clusters or platoons of vehicles, as the mechanism that causes the presence of this synchronized traffic state with a high flow. This platoon formation is one of the most interesting phenomena observed in traffic flows and plays an important role both in manual and automated highway systems (AHS). Simulation results, obtained from a single-lane system under periodic boundary conditions indicate that in the density region where the synchronized state is observed, most vehicles travel together in platoons with approximately the same speed and small spatial distances. The examination of velocity variations and individual vehicle gaps shows that the flow corresponding to the synchronized state is stable, safe and highly correlated. Moreover, results indicate that the observed platoon formation in real traffic is reproduced in simulations by the relation between vehicle headway and velocity that is embedded in the dynamics definition of the CA model. (general)

Improving Precision and Reducing Runtime of Microscopic Traffic Simulators through Stratified Sampling

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Khewal Bhupendra Kesur

2013-01-01

Full Text Available This paper examines the application of Latin Hypercube Sampling (LHS and Antithetic Variables (AVs to reduce the variance of estimated performance measures from microscopic traffic simulators. LHS and AV allow for a more representative coverage of input probability distributions through stratification, reducing the standard error of simulation outputs. Two methods of implementation are examined, one where stratification is applied to headways and routing decisions of individual vehicles and another where vehicle counts and entry times are more evenly sampled. The proposed methods have wider applicability in general queuing systems. LHS is found to outperform AV, and reductions of up to 71% in the standard error of estimates of traffic network performance relative to independent sampling are obtained. LHS allows for a reduction in the execution time of computationally expensive microscopic traffic simulators as fewer simulations are required to achieve a fixed level of precision with reductions of up to 84% in computing time noted on the test cases considered. The benefits of LHS are amplified for more congested networks and as the required level of precision increases.

Setting the bar: Standards for ecosystem services

Science.gov (United States)

Polasky, Stephen; Tallis, Heather; Reyers, Belinda

2015-01-01

Progress in ecosystem service science has been rapid, and there is now a healthy appetite among key public and private sector decision makers for this science. However, changing policy and management is a long-term project, one that raises a number of specific practical challenges. One impediment to broad adoption of ecosystem service information is the lack of standards that define terminology, acceptable data and methods, and reporting requirements. Ecosystem service standards should be tailored to specific use contexts, such as national income and wealth accounts, corporate sustainability reporting, land-use planning, and environmental impact assessments. Many standard-setting organizations already exist, and the research community will make the most headway toward rapid uptake of ecosystem service science by working directly with these organizations. Progress has been made in aligning with existing organizations in areas such as product certification and sustainability reporting, but a major challenge remains in mainstreaming ecosystem service information into core public and private use contexts, such as agricultural and energy subsidy design, national income accounts, and corporate accounts. PMID:26082540

Global environmental policy strategies. ''Environment and development'' in north-south relations

International Nuclear Information System (INIS)

Bruckmeier, K.

1994-01-01

Global environmental policy has hardly made headway after the United Nations World Conference on Environment and Development (UNCED) in Rio in June 1992, despite there being no shortage of programmes, institutions, and actors. Obviously, formal structures for political action based on the system of institutions of the United Nations do not suffice. Global environmental policy strategies must reach further, overcoming system-immanent obstacles to sustainable development. This necessitates analyzing the causes of environmental destruction and making a critical evaluation of the relations between the societies of the North and South that received their imprint from development policies. Only after such a preliminary elucidation by interdisciplinary approaches in the light of political and ecological economy and human ecology does an empirical analysis of politically controlled processes in environmental and development policy make sense. The analysis points to strategies for this international political field that rely on non-governmental actors and social movements, and question the traditional European model of an environmental policy determined by government institutions. (orig./UA) [de

I’ll Show You the Way: Risky Driver Behavior When “Following a Friend”

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Jaimie McNabb

2017-05-01

Full Text Available Previous research examining social influences on driving behavior has primarily focused on the effects of passengers and surrounding vehicles (e.g., speed contagion. Of current interest was the interaction between drivers that occurs in a “following a friend” scenario, i.e., the driver of one vehicle (the leader knows how to get to the desired destination while the driver of a second vehicle (the follower does not. Sixteen participants drove through a simulated city in a driving simulator under three conditions: (i a baseline condition in which they could choose their own route, (ii a navigation system condition in which they were given audible route instructions, and (iii a “follow a friend” condition in which they required to follow a simulated vehicle. In the follow a friend condition, drivers engaged in significantly more risky behaviors (in comparison to the other conditions such as making more erratic and higher speed turns and lane changes, maintaining overall higher speed, as well as maintaining a shorter time headway when following a lead vehicle. These effects suggest a relationship to time pressure caused by a fear of getting lost.

Schizophrenia genomics and proteomics: are we any closer to biomarker discovery?

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Kramer Alon

2009-01-01

Full Text Available Abstract The field of proteomics has made leaps and bounds in the last 10 years particularly in the fields of oncology and cardiovascular medicine. In comparison, neuroproteomics is still playing catch up mainly due to the relative complexity of neurological disorders. Schizophrenia is one such disorder, believed to be the results of multiple factors both genetic and environmental. Affecting over 2 million people in the US alone, it has become a major clinical and public health concern worldwide. This paper gives an update of schizophrenia biomarker research as reviewed by Lakhan in 2006 and gives us a rundown of the progress made during the last two years. Several studies demonstrate the potential of cerebrospinal fluid as a source of neuro-specific biomarkers. Genetic association studies are making headway in identifying candidate genes for schizophrenia. In addition, metabonomics, bioinformatics, and neuroimaging techniques are aiming to complete the picture by filling in knowledge gaps. International cooperation in the form of genomics and protein databases and brain banks is facilitating research efforts. While none of the recent developments described here in qualifies as biomarker discovery, many are likely to be stepping stones towards that goal.

Determination of calcitonin; Bestimmung von Kalzitonin

Energy Technology Data Exchange (ETDEWEB)

Goerges, R. [Klinik fuer Nuklearmedizin, Klinikum Essen, Univ. Duisburg/Essen (Germany); Gemeinschaftspraxis fuer Nuklearmedizin, Duisburg (Germany)

2005-03-01

Calcitonin in serum is a comparatively highly sensitive, specific and reliable tumor marker of central relevance for the diagnosis and follow-up of medullary thyroidal C-cell carcinoma (MTC) and neoplastic C-cell hyperplasia (CCH). It is seen considerably less often in other tumor entities. For determination we recommend immunometric two-site assays of approximately 1-2 pg/ml sensitivity. Higher MTC specificity is achieved by assays focussing on a largely selective determination of monomeric calcitonin. If this is realized, basal calcitonin levels are already greatly relevant for MTC or CCH diagnosis. The diagnostic sensitivity and specificity of calcitonin determination may be further enhanced by means of pentagastrin test, but even then false positive results are clinically relevant especially in benign CCH and renal insufficiency. In family screening in case of MTC patients, moleculargenetic techniques have become the procedure of choice and have now largely replaced the pentagastrin test. Calcitonin screening in adenomatous goitre (struma nodosa) is making headway. Although this accounts for only 10% of thyroidal malignomas (which are in fact rare), and the recommended levels of intervention will result in many unnecessary surgical operations, early tumor staging definitely increases the chances for curative intervention. (orig.)

Age and inconsistency in driving performance.

Science.gov (United States)

Bunce, David; Young, Mark S; Blane, Alison; Khugputh, Priya

2012-11-01

Research in cognitive neuropsychology suggests that investigation of the within-person variability, or inconsistency, of cognitive performance may provide valuable insights into ageing mental processes. It is rare though, for this interest in intraindividual variability to extend to everyday activities. As this may provide important information about driving behaviour, we therefore assessed age differences in driving inconsistency in younger (n=24, M age=21.29 years) and older (n=21, M age=71.24 years) persons who drove in residential, urban and motorway conditions in a fully immersive driving simulator. In measures of headway (maintaining a safe distance to a preceding vehicle) and lateral lane position, older drivers exhibited significantly greater performance inconsistency, and this was particularly marked in the faster motorway condition. Older drivers also recorded greater perceived mental demands associated with driving, and greater within-person variability across a range of cognitive measures. The findings suggest that age-related deficits in attentional and executive control may affect the consistency of driving performance in older persons. Discussion considers interventions to introduce in-vehicle systems to help maintain attention in older drivers, and to intervene when safety-critical boundaries are exceeded. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effect of adaptive cruise control systems on mixed traffic flow near an on-ramp

Science.gov (United States)

Davis, L. C.

2007-06-01

Mixed traffic flow consisting of vehicles equipped with adaptive cruise control (ACC) and manually driven vehicles is analyzed using car-following simulations. Simulations of merging from an on-ramp onto a freeway reported in the literature have not thus far demonstrated a substantial positive impact of ACC. In this paper cooperative merging for ACC vehicles is proposed to improve throughput and increase distance traveled in a fixed time. In such a system an ACC vehicle senses not only the preceding vehicle in the same lane but also the vehicle immediately in front in the other lane. Prior to reaching the merge region, the ACC vehicle adjusts its velocity to ensure that a safe gap for merging is obtained. If on-ramp demand is moderate, cooperative merging produces significant improvement in throughput (20%) and increases up to 3.6 km in distance traveled in 600 s for 50% ACC mixed flow relative to the flow of all-manual vehicles. For large demand, it is shown that autonomous merging with cooperation in the flow of all ACC vehicles leads to throughput limited only by the downstream capacity, which is determined by speed limit and headway time.

Quantum heating as an alternative of reheating

Science.gov (United States)

Akhmedov, Emil T.; Bascone, Francesco

2018-02-01

To model a realistic situation for the beginning we consider massive real scalar ϕ4 theory in a (1 +1 )-dimensional asymptotically static Minkowski spacetime with an intermediate stage of expansion. To have an analytic headway we assume that scalars have a big mass. At past and future infinities of the background we have flat Minkowski regions which are joint by the inflationary expansion region. We use the tree-level Keldysh propagator in the theory in question to calculate the expectation value of the stress-energy tensor which is, thus, due to the excitations of the zero-point fluctuations. Then we show that even for large mass, if the de Sitter expansion stage is long enough, the quantum loop corrections to the expectation value of the stress-energy tensor are not negligible in comparison with the tree-level contribution. That is revealed itself via the excitation of the higher-point fluctuations of the exact modes: during the expansion stage a nonzero particle number density for the exact modes is generated. This density is not Planckian and serves as a quench which leads to a thermalization in the out Minkowski stage.

Cine club

CERN Multimedia

Cine club

2015-01-01

Wednesday 27 May 2015 at 20:00 CERN Council Chamber Wait Until Dark Directed by Terence Young USA, 1967, 108 minutes   When Sam Hendrix carries a doll across the Canada-US border, he sets off a chain of events that will lead to a terrifying ordeal for his blind wife, Susy. The doll was stuffed with heroin and when it cannot be located, its owner, a Mr. Roat, stages a piece of theatre in an attempt to recover it. He arranges for Sam to be away from the house for a day and then has two con men, Mike Talman and a Mr. Carlito, alternately encourage or scare Susy into telling them where the doll is hidden. Talman pretends to be an old friend of Sam's while Carlito pretends to be a police officer. Despite their best efforts they make little headway as Susy has no idea where the doll might be, leading Mr. Roat to take a somewhat more violent approach to getting the information from her. Original version English; French subtitles   Wednesday 3 Juin 2015 at 20:00 CERN Council Chamber Sogn...

Level of Bus Performance Based On the Relationship Between Distance and Travel Time of Universiti Tun Hussein Onn Malaysia (UTHM Bus Services

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Prasetijo Joewono

2017-01-01

Full Text Available UTHM bus service is an important transport mode for most students at Universiti Tun Hussein Onn because it such primary public vehicle to support students movements around the campus, within and outside student apartments. This service is often associated with the quality of service in terms of time, stops and comforts. Therefore, this following study is focused on investigation on several UTHM bas routes which was based on bas operations such as distance and travel time/travel distance that would determine the level of service provided. Primary data were collected mainly to obtain information relate to speed, bas position, time movement/circulations of bus and time headway. These were obtained by installing GPS-Slute Gear i-trail along bus travels. In addition, additional data were collected by exploring previous studies regarding to the bus services such as Highway Capacity Manual (HCM 2010. The approach used was based on assessment of progress used to determine the level of quest service and such obstacle frequently occurs with results on bus delays, volume of unequal that can be overcome according to the assessments that have been provided.

A preliminary survey analysis of school shuttle bus system towards smart mobility solutions

Science.gov (United States)

Yue, Wong Seng; Hoy, Cheong Wan; Chye, Koh Keng

2017-10-01

Mobility and accessibility are crucial indicators of urban development. Public transport in the urban areas came into existence to fulfil transportation needs as well as mobility and accessibility demands. Ridership can be affected by the quality and quantity of transit service. However, technical improvements are needed for such as real-time bus information, controlling run time and headway delay. Thus, this paper is aimed to carry out a preliminary survey to determine the problems of school shuttle bus that faced by the students in a selected educational institution, their perceptions of using shuttle bus tracking and information mobile application and impacts of real-time information of public transits on bus ridership and towards smart mobility solutions. Efficient public transportation system needs further investigation about the role of mobile application for the bus tracking system in supporting smart mobility actions and real-time information. The proposed application also provides a smart solution for the management of public infrastructures and urban facilities in Malaysia in future. Eventually, this study opens an opportunity to improve Malaysian quality of life on the public value that created for the city as a whole.

Exploring the impact of signal types and adjacent vehicles on drivers' choices after the onset of yellow

Science.gov (United States)

Bao, Ji; Chen, Qun; Luo, Dandan; Wu, Yuli; Liang, Zuli

2018-06-01

Drivers' choices at signalized intersections may be made in great uncertainty after the onset of yellow, which creates potential hazards for road safety. These choices are analyzed and modeled based on field observations at three comparable signalized intersections in Changsha, China. The results show that intersections without monitoring devices widen the indecision zone, which can increase the risk of rear-end collisions and the uncertainty of drivers' decision-making. In addition, drivers are more likely to stop during the yellow interval at intersections equipped with a green signal countdown device (GSCD) than at those with a green signal flashing device (GSFD). Subsequently, according to the results of a binary logistic regression model (BLRM), drivers' decision making at the onset of the yellow indication is greatly influenced by the vehicle's spot speed, the distance to the stop line, and signal and monitoring devices. The presence of an adjacent vehicle with a short space headway can particularly motivate the following driver to make a go-decision after the first driver chooses to pass the intersection. However, a stop-decision by a driver in an adjacent lane can also prompt the following driver to stop.

Impacts of Snowy Weather Conditions on Expressway Traffic Flow Characteristics

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Jiancheng Weng

2013-01-01

Full Text Available Snowy weather will significantly degrade expressway operations, reduce service levels, and increase driving difficulty. Furthermore, the impact of snow varies in different types of roads, diverse cities, and snow densities due to different driving behavior. Traffic flow parameters are essential to decide what should be appropriate for weather-related traffic management and control strategies. This paper takes Beijing as a case study and analyzes traffic flow data collected by detectors in expressways. By comparing the performance of traffic flow under normal and snowy weather conditions, this paper quantitatively describes the impact of adverse weather on expressway volume and average speeds. Results indicate that average speeds on the Beijing expressway under heavy snow conditions decrease by 10–20 km/h when compared to those under normal weather conditions, the vehicle headway generally increases by 2–4 seconds, and the road capacity drops by about 33%. This paper also develops a specific expressway traffic parameter reduction model which proposes reduction coefficients of expressway volumes and speeds under various snow density conditions in Beijing. The conclusions paper provide effective foundational parameters for urban expressway controls and traffic management under snow conditions.

The Rise of Mobile Technology on the Financial Sector in Zimbabwe

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Paul Mupfiga

2017-07-01

Full Text Available The emergence of technology has revolted the way that the financial industry operates and the increasing use of mobile gadgets has changed the banking system from the traditional brick and mortar building to a virtual system. The sudden rise in use and innovation of smart mobile phones, mobile personal computers, tablets and various other mobile electronic gadgets has resulted in the rise of mobile financial products. Rapid quickening innovative headways are making completely new business suggestions, for example, crowd financing, shared loaning, advanced monetary forms, versatile managing an account, online speculation and new instalment frameworks. Zimbabwe's mobile technology use is currently on the rise too as mobile service providers like Econet are enabling the connection between consumers and financial related products. Despite the fact that innovation without a doubt brings benefits, prominent specialized disappointments in the money related part lately are disturbing and several negative factors are to some extent affecting production. Drawbacks like cybercrime, resistance to change, and compatibility of mobile gadgets are affecting the information technology environment. This paper highlights the rise of mobile technology in the financial sector in Zimbabwe.

An extended heterogeneous car-following model accounting for anticipation driving behavior and mixed maximum speeds

Science.gov (United States)

Sun, Fengxin; Wang, Jufeng; Cheng, Rongjun; Ge, Hongxia

2018-02-01

The optimal driving speeds of the different vehicles may be different for the same headway. In the optimal velocity function of the optimal velocity (OV) model, the maximum speed vmax is an important parameter determining the optimal driving speed. A vehicle with higher maximum speed is more willing to drive faster than that with lower maximum speed in similar situation. By incorporating the anticipation driving behavior of relative velocity and mixed maximum speeds of different percentages into optimal velocity function, an extended heterogeneous car-following model is presented in this paper. The analytical linear stable condition for this extended heterogeneous traffic model is obtained by using linear stability theory. Numerical simulations are carried out to explore the complex phenomenon resulted from the cooperation between anticipation driving behavior and heterogeneous maximum speeds in the optimal velocity function. The analytical and numerical results all demonstrate that strengthening driver's anticipation effect can improve the stability of heterogeneous traffic flow, and increasing the lowest value in the mixed maximum speeds will result in more instability, but increasing the value or proportion of the part already having higher maximum speed will cause different stabilities at high or low traffic densities.

Advances in the proteomic discovery of novel therapeutic targets in cancer

Directory of Open Access Journals (Sweden)

Guo S

2013-10-01

Full Text Available Shanchun Guo,1 Jin Zou,2 Guangdi Wang3 1Department of Microbiology, Biochemistry, and Immunology, Morehouse School of Medicine, 2Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, GA, USA; 3Research Centers in Minority Institutions Cancer Research Program, Xavier University of Louisiana, New Orleans, LA, USA Abstract: Proteomic approaches are continuing to make headways in cancer research by helping to elucidate complex signaling networks that underlie tumorigenesis and disease progression. This review describes recent advances made in the proteomic discovery of drug targets for therapeutic development. A variety of technical and methodological advances are overviewed with a critical assessment of challenges and potentials. A number of potential drug targets, such as baculoviral inhibitor of apoptosis protein repeat-containing protein 6, macrophage inhibitory cytokine 1, phosphoglycerate mutase 1, prohibitin 1, fascin, and pyruvate kinase isozyme 2 were identified in the proteomic analysis of drug-resistant cancer cells, drug action, and differential disease state tissues. Future directions for proteomics-based target identification and validation to be more translation efficient are also discussed. Keywords: proteomics, cancer, therapeutic target, signaling network, tumorigenesis

Fatigue Performance Assessment of Composite Arch Bridge Suspenders Based on Actual Vehicle Loads

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Bin Chen

2015-01-01

Full Text Available In the through arch bridges, the suspenders are the key components connecting the arch rib and the bridge deck in the middle, and their safety is an increasing focus in the field of bridge engineering. In this study, various vehicle traffic flow parameters are investigated based on the actual vehicle data acquired from the long-term structural health monitoring system of a composite arch bridge. The representative vehicle types and the probability density functions of several parameters are determined, including the gross vehicle weight, axle weight, time headway, and speed. A finite element model of the bridge structure is constructed to determine the influence line of the cable force for various suspenders. A simulated vehicle flow, generated using the Monte Carlo method, is applied on the influence lines of the target suspender to determine the stress process, and then the stress amplitude spectrum is obtained based on the statistical analysis of the stress process using the rainflow counting method. The fatigue performance levels of various suspenders are analyzed according to the Palmgren-Miner linear cumulative damage theory, which helps to manage the safety of the suspenders.

APF-Based Car Following Behavior Considering Lateral Distance

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Zhao-Sheng Yang

2013-01-01

Full Text Available Considering the influence of lateral distance on consecutive vehicles, this paper proposes a new car following model based on the artificial potential field theory (APF. Traditional car following behaviors all assume that the vehicles are driving along the middle of a lane. Different from the traditional car following principles, this incorporation of APF offers a potential breakthrough in the fields of car following theory. The individual vehicle can be represented as a unit point charge in electric field, and the interaction of the attractive potential energy and the repellent potential energy between vehicles simplifies the various influence factors on the target vehicle in actual following behavior. Consequently, it can make a better analysis of the following behavior under the lateral separation. Then, the proposed model has been demonstrated in simulation environment, through which the space-time trajectories and the potential energy change regulation are obtained. Simulations verify that the following vehicle's behavior is vulnerable to be affected by lateral distance, where the attractive potential energy tends to become repellent potential energy as the longitudinal distance decreases. The search results prove that the proposed model quantifies the relations between headway and potential energy and better reflects the following process in real-world situation.

Developing a Distributed Consensus-Based Cooperative Adaptive Cruise Control System for Heterogeneous Vehicles with Predecessor Following Topology

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Ziran Wang

2017-01-01

Full Text Available Connected and automated vehicle (CAV has become an increasingly popular topic recently. As an application, Cooperative Adaptive Cruise Control (CACC systems are of high interest, allowing CAVs to communicate with each other and coordinating their maneuvers to form platoons, where one vehicle follows another with a constant velocity and/or time headway. In this study, we propose a novel CACC system, where distributed consensus algorithm and protocol are designed for platoon formation, merging maneuvers, and splitting maneuvers. Predecessor following information flow topology is adopted for the system, where each vehicle only communicates with its following vehicle to reach consensus of the whole platoon, making the vehicle-to-vehicle (V2V communication fast and accurate. Moreover, different from most studies assuming the type and dynamics of all the vehicles in a platoon to be homogenous, we take into account the length, location of GPS antenna on vehicle, and braking performance of different vehicles. A simulation study has been conducted under scenarios including normal platoon formation, platoon restoration from disturbances, and merging and splitting maneuvers. We have also carried out a sensitivity analysis on the distributed consensus algorithm, investigating the effect of the damping gain on convergence rate, driving comfort, and driving safety of the system.

Coal combustion aerothermochemistry research. Final report

Energy Technology Data Exchange (ETDEWEB)

Witte, A.B.; Gat, N.; Denison, M.R.; Cohen, L.M.

1980-12-15

On the basis of extensive aerothermochemistry analyses, laboratory investigations, and combustor tests, significant headway has been made toward improving the understanding of combustion phenomena and scaling of high swirl pulverized coal combustors. A special attempt has been made to address the gap between scientific data available on combustion and hardware design and scaling needs. Both experimental and theoretical investigations were conducted to improve the predictive capability of combustor scaling laws. The scaling laws derived apply to volume and wall burning of pulverized coal in a slagging high-swirl combustor. They incorporate the findings of this investigation as follows: laser pyrolysis of coal at 10/sup 6/ K/sec and 2500K; effect of coal particle shape on aerodynamic drag and combustion; effect of swirl on heat transfer; coal burnout and slag capture for 20 MW/sub T/ combustor tests for fine and coarse coals; burning particle trajectories and slag capture; particle size and aerodynamic size; volatilization extent and burnout fraction; and preheat level. As a result of this work, the following has been gained: an increased understanding of basic burning mechanisms in high-swirl combustors and an improved model for predicting combustor performance which is intended to impact hardware design and scaling in the near term.

Science, Passion & Compassion vs. Cancer: Tania Crombet MD PhD, Director of Clinical Research. Molecular Immunology Center, Havana.

Science.gov (United States)

Gory, Conner

2016-10-01

Soon after the Molecular Immunology Center (CIM) was established in 1994 (a founding institution of Havana's biotechnology and pharmaceutical campus known as the scientific pole), Dr Crombet completed her master's thesis there. She joined CIM's team in 1998 and in 2004 was designated Director of Clinical Research. She has participated in the research, development and clinical trials of some of Cuba's most innovative therapies and vaccines, including CIMAvax-EGF for non-small cell lung cancer patients. In 2015, this therapy completed Phase IV clinical trials in Cuba and is now used in primary health care services throughout the country's national health system. CIM and Roswell Park Cancer Institute (Buffalo, New York) received US Department of Treasury approval in 2015 to test CIMAvax-EGF and other CIM products in the United States, opening the way for the Food and Drug Administration (FDA) to consider joint ground-breaking Phase I and II clinical trials in the USA. Recent regulatory changes introduced by President Barack Obama may make applying for such licenses a thing of the past-at least that is what researchers hope. In any case, the work of Dr Crombet and the teams at CIM is making headway in cancer immunotherapy, within the broader goals of the institution's mandate…the subject of our interview.

Modelo de demanda para un tren de pasajeros entre Tunja y Bogotá

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Luis Gabriel Márquez

2009-11-01

Full Text Available Este artículo presenta los resultados de una encuesta de preferencias declaradas en un experimento de elección discreta, diseñado para examinar la demanda potencial de un nuevo sistema de transporte de pasajeros tipo tren entre Tunja y Bogotá. El estudio investiga acerca del comportamiento en la elección de tres modos de transporte: bus, tren y auto. Cada modo fue representado en términos del costo, tiempo de viaje e intervalo de tiempo entre despachos con un modelo logit mixto que incluye para los individuos la variable asiduidad. El modelo se utilizó para experimentar con distintos escenarios y se encontró para cada uno de ellos el reparto modal correspondiente. / This paper presents the results of stated-preference in a discrete choice experiments designed to examine the potential demand for a new type of passenger train between Tunja and Bogotá. The study investigates choice behaviour between three modes of transportation: bus, train and car. Each mode is represented in terms of cost, travel time and headway with a mixed logit model, which includes regularly for individuals. The model was used to experiment with different scenarios, finding the modal split for each.

Thermodynamic treatment of nonphysical systems: formalism and an example (single-lane traffic)

International Nuclear Information System (INIS)

Reiss, H.; Hammerich, A.D.; Montroll, E.W.

1986-01-01

An effort is made to introduce thermodynamic and statistical thermodynamic methods into the treatment of nonphysical (e.g., social, economic, etc.) systems. Emphasis is placed on the use of the entire thermodynamic framework, not merely entropy. Entropy arises naturally, related in a simple manner to other measurables, but does not occupy a primary position in the theory. However, the maximum entropy formalism is a convenient procedure for deriving the thermodynamic analog framework in which undetermined multipliers are thermodynamic-like variables which summarize the collective behavior of the system. The authors discuss the analysis of Levine and his coworkers showing that the maximum entropy formalism is the unique algorithm for achieving consistent inference of probabilities. The thermodynamic-like formalism for treating a single lane of vehicular traffic is developed and applied to traffic in which the interaction between cars is chosen to be a particular form of the ''follow-the-leader'' type. The equation of state of the traffic, the distributions of velocity and headway, and the various thermodynamic-like parameters, e.g., temperature (collective sensitivity), pressure, etc. are determined for the example of the Holland Tunnel. Nearest-neighbor and pair correlation functions for the vehicles are also determined. Interesting and suggestive results are obtained

[The necessity and possibility of developing skills in daily living activities in children attending a special kindergarten for the physically handicapped--demonstrated by means of a five-year-old boy suffering from spastic hemiparesis (author's transl)].

Science.gov (United States)

Burgheim-Raguss, B

1980-02-01

Within the framework of an empirical study carried out in a special kindergarten it was attempted to answer the question whether it is necessary and possible in such an institution to develop the children's skills in daily living activities. A six month systematic programme was set up for a five-year-old boy suffering from spastic hemiparesis which was designed to develop his skills in personal hygiene, and general behaviour in the kitchen area. In preparing the programme each of the two fields was first treated separately in detail, then the common factors taken into account. The programm's subdivision into an ultimate goal and two partial goals assisted the implementation of the eighteen training steps. A comparision of the knowledge of, and skills in, the two fields before and after the training showed that they had increased both in quantity and quality. As the boy still showed a headway over his peers - comparable in their disabilities - three years after completion of the programme as far as independence was concerned, it can be said that special training in daily living activities can and must be carried out in a special kindergarten for physically handicapped children provided the training is based on a specialized and fully structured programme.

Fault tolerant computer control for a Maglev transportation system

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Lala, Jaynarayan H.; Nagle, Gail A.; Anagnostopoulos, George

1994-01-01

Magnetically levitated (Maglev) vehicles operating on dedicated guideways at speeds of 500 km/hr are an emerging transportation alternative to short-haul air and high-speed rail. They have the potential to offer a service significantly more dependable than air and with less operating cost than both air and high-speed rail. Maglev transportation derives these benefits by using magnetic forces to suspend a vehicle 8 to 200 mm above the guideway. Magnetic forces are also used for propulsion and guidance. The combination of high speed, short headways, stringent ride quality requirements, and a distributed offboard propulsion system necessitates high levels of automation for the Maglev control and operation. Very high levels of safety and availability will be required for the Maglev control system. This paper describes the mission scenario, functional requirements, and dependability and performance requirements of the Maglev command, control, and communications system. A distributed hierarchical architecture consisting of vehicle on-board computers, wayside zone computers, a central computer facility, and communication links between these entities was synthesized to meet the functional and dependability requirements on the maglev. Two variations of the basic architecture are described: the Smart Vehicle Architecture (SVA) and the Zone Control Architecture (ZCA). Preliminary dependability modeling results are also presented.

Analysis of eleven phenolic compounds including novel p-coumaroyl derivatives in lettuce (Lactuca sativa L.) by ultra-high-performance liquid chromatography with photodiode array and mass spectrometry detection.

Science.gov (United States)

Ribas-Agustí, Albert; Gratacós-Cubarsí, Marta; Sárraga, Carmen; García-Regueiro, José-Antonio; Castellari, Massimo

2011-01-01

Lettuce is a widely consumed vegetable and a good source of phenolic compounds. Several factors (genetic, agronomical and environmental) can influence the lettuce composition; their effects are not completely defined and more studies are needed on this topic. To develop an improved ultra-high-performance liquid chromatography (UHPLC) method to quantify the main target intact phenolic compounds in lettuce. UHPLC identification of the compounds was supported by PAD spectra and MS(n) analyses. Quantification was carried out by PAD, by creating matrix-matched calibration curves at the specific wavelength for each compound. Sample pretreatment was simplified, with neither purification nor hydrolysis steps. Chromatographic conditions were chosen to minimise matrix interferences and to give a suitable separation of the major phenolic compounds within 27 min. The method allowed the quantification of 11 intact phenolic compounds in Romaine lettuces, including phenolic acids (caffeoyl and p-coumaroyl esters) and flavonoids (quercetin glycosides). Four p-coumaroyl esters were tentatively identified and quantified for the first time in lettuce. The main intact phenolic compounds, including four novel p-coumaroyl esters, were simultaneously quantified in lettuce with optimal performances and a reduced total time of analysis. These findings make headway in the understanding of the lettuce phytochemicals with potential nutritional relevance. Copyright © 2011 John Wiley & Sons, Ltd.

Exploring compassion: implications for contemporary nursing. Part 2.

Science.gov (United States)

Straughair, Collette

A range of contemporary political and professional literature endorse the principle of compassion in nursing as a core and underpinning philosophy fundamental to the profession. However, despite pledges to ensure that compassion lies at the heart of nursing, the concept has not been clearly defined. It is evident that uncovering the true meaning is complex and challenging owing to its subjective nature. In light of this, several implications must be considered. Effective student nurse recruitment is essential to ensure that the most appropriate individuals are selected. Contemporary marketing campaigns must be implemented, and recruitment strategies developed, which consider specific values and attitudes. Service user involvement in recruitment and selection, curriculum planning and learning and teaching strategies, and post-qualification education, can enhance nurses' understanding of the patient perspective and make headway in embedding compassion as a core nursing value. Additionally, effective role modelling in practice which demonstrates high-quality compassionate nursing care is essential. Nurses must be adequately supported in the clinical environment to facilitate compassionate behaviours and clinical leadership at all levels must uphold political and professional pledges to achieve this. Consideration of these implications for practice is essential to ensure that nurses are able to respond to patients with humanity and kindness, and deliver high-quality, compassionate care to all.

Perubahan Nilai Ekivalensi Mobil Penumpang Akibat Perubahan Karakteristik Operasional Kendaraan di Jalan Kota Semarang

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EPF. Eko Yulipriyono

2017-07-01

Full Text Available Passenger Car Equivalent (PCE is a conversion factor to make equal the various types of vehicles that operating on the road section into one type of vehicles i.e. passenger cars. Indonesian Highway Capacity Manual (MKJI 1997 has set the PCE values for various types of vehicle groups either motorized. PCE values of various types of vehicles are not absolute because many factors that affect can change over time and development of automotive technology. This study aimed to find out the changes of PCE value that occurs. As for the purpose of research to determine the current number of PCE values due to the change of operational characteristics of vehicles on a highway especially for urban highways. Data analysis for the determination of PCE values used: time headway method, speed method, capacity method, and vehicle dimension method. The conclusion of this study: PCE of light vehicles (LV = 1 still in accordance with MJKI 1997; PCE of heavy vehicles (HV varied depending on the road types. PCE of heavy vehicles that according to MKJI 1997 is used as a median; PCE of motorcycles (MC of MKJI 1997 need to be adjusted to 0.4 or more, particularly in the calculation of actualy traffic flow.

Análise Empírica do Senso de Controle: Buscando Entender o Excesso de Confiança

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Wesley Mendes-da-Silva

2009-04-01

Full Text Available In the emerging field of behavioral finance, where details of human behavior concerning financial decision making are broached, implications of cognitive psychology and sociology are considered. In this way, scientific production, still small but making steady headway, of this thematic in the national scope has essentially laid more focus on the consequences of the cognitive biases of agents, which can reduce the validity of judgments which have been made. Some of the cognitive biases considered in literature, such as overconfidence and procrastination, are influenced by the sense of control that each person possesses. In this way, this article aims to verify associations between age and sense of control, analyzing the mediating effect of other personal characteristics on this association. The study stems from data collected during the first trimester of 2006, from 421 people living in Brazil. The main results suggest a significant quadratic association, like an inverted U curve, between age and sense of control, with this relationship being influenced by the level of education and the perceived general health conditions of each individual. It would seem, therefore, that the evolution of people’s sense of control during their lifetimes is influenced by their education and global health.

Staying Connected on the Road: A Comparison of Different Types of Smart Phone Use in a Driving Simulator

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McNabb, Jaimie; Gray, Rob

2016-01-01

Previous research on smart phone use while driving has primarily focused on phone calls and texting. Drivers are now increasingly using their phone for other activities during driving, in particular social media, which have different cognitive demands. The present study compared the effects of four different smart phone tasks on car-following performance in a driving simulator. Phone tasks were chosen that vary across two factors: interaction medium (text vs image) and task pacing (self-paced vs experimenter-paced) and were as follows: Text messaging with the experimenter (text/other-paced), reading Facebook posts (text/self-paced), exchanging photos with the experimenter via Snapchat (image, experimenter -paced), and viewing updates on Instagram (image, experimenter -paced). Drivers also performed a driving only baseline. Brake reaction times (BRTs) were significantly greater in the text-based conditions (Mean = 1.16 s) as compared to both the image-based conditions (Mean = 0.92 s) and the baseline (0.88 s). There was no significant difference between BRTs in the image-based and baseline conditions and there was no significant effect of task-pacing. Similar results were obtained for Time Headway variability. These results are consistent with the picture superiority effect found in memory research and suggest that image-based interfaces could provide safer ways to “stay connected” while driving than text-based interfaces. PMID:26886099

The effects of in-vehicle tasks and time-gap selection while reclaiming control from adaptive cruise control (ACC) with bus simulator.

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Lin, Tsang-Wei; Hwang, Sheue-Ling; Su, Jau-Ming; Chen, Wan-Hui

2008-05-01

This research aimed to find out the effects of in-vehicle distractions and time-gap settings with a fix-based bus driving simulator in a following scenario. Professional bus drivers were recruited to perform in-vehicle tasks while driving with adaptive cruise control (ACC) of changeable time-gap settings in freeway traffic. Thirty subjects were divided equally into three groups for different in-vehicle task modes (between subjects), including no task distraction, hands-free, and manual modes. Further, time-gap settings for the experimental ACC were: shorter than 1.0 s, 1.0-1.5 s, 1.5-2.0 s, and longer than 2.0 s (within subjects). Longitudinal (mean headway, forward collision rate, and response time) and lateral control (mean lateral lane position and its standard deviation) performance was assessed. In the results, longitudinal control performance was worsened by both shorter time-gaps and heavier in-vehicle tasks. But the interaction indicated that the harm by heavier in-vehicle distraction could be improved by longer time-gaps. As for the lateral control, it would only be negatively affected by shorter time-gap settings. This research indicates the effects of time-gaps and in-vehicle distraction, as well as the interaction. Proper time-gap selection under different in-vehicle distractions can help avoid accidents and keep safe.

Staying Connected on the Road: A Comparison of Different Types of Smart Phone Use in a Driving Simulator.

Directory of Open Access Journals (Sweden)

Jaimie McNabb

Full Text Available Previous research on smart phone use while driving has primarily focused on phone calls and texting. Drivers are now increasingly using their phone for other activities during driving, in particular social media, which have different cognitive demands. The present study compared the effects of four different smart phone tasks on car-following performance in a driving simulator. Phone tasks were chosen that vary across two factors: interaction medium (text vs image and task pacing (self-paced vs experimenter-paced and were as follows: Text messaging with the experimenter (text/other-paced, reading Facebook posts (text/self-paced, exchanging photos with the experimenter via Snapchat (image, experimenter-paced, and viewing updates on Instagram (image, experimenter-paced. Drivers also performed a driving only baseline. Brake reaction times (BRTs were significantly greater in the text-based conditions (Mean = 1.16 s as compared to both the image-based conditions (Mean = 0.92 s and the baseline (0.88 s. There was no significant difference between BRTs in the image-based and baseline conditions and there was no significant effect of task-pacing. Similar results were obtained for Time Headway variability. These results are consistent with the picture superiority effect found in memory research and suggest that image-based interfaces could provide safer ways to "stay connected" while driving than text-based interfaces.

Rational-driver approximation in car-following theory

Science.gov (United States)

Lubashevsky, Ihor; Wagner, Peter; Mahnke, Reinhard

2003-11-01

The problem of a car following a lead car driven with constant velocity is considered. To derive the governing equations for the following car dynamics a cost functional is constructed. This functional ranks the outcomes of different driving strategies, which applies to fairly general properties of the driver behavior. Assuming rational-driver behavior, the existence of the Nash equilibrium is proved. Rational driving is defined by supposing that a driver corrects continuously the car motion to follow the optimal path minimizing the cost functional. The corresponding car-following dynamics is described quite generally by a boundary value problem based on the obtained extremal equations. Linearization of these equations around the stationary state results in a generalization of the widely used optimal velocity model. Under certain conditions (the “dense traffic” limit) the rational car dynamics comprises two stages, fast and slow. During the fast stage a driver eliminates the velocity difference between the cars, the subsequent slow stage optimizes the headway. In the dense traffic limit an effective Hamiltonian description is constructed. This allows a more detailed nonlinear analysis. Finally, the differences between rational and bounded rational driver behavior are discussed. The latter, in particular, justifies some basic assumptions used recently by the authors to construct a car-following model lying beyond the frameworks of rationality.

Driver Behavioral Changes through Interactions with an Automatic Brake System for Collision Avoidance

Science.gov (United States)

Itoh, Makoto; Fujiwara, Yusuke; Inagaki, Toshiyuki

This paper discusses driver's behavioral changes as a result of driver's use of an automatic brake system for preventing a rear-end collision from occurring. Three types of automatic brake systems are investigated in this study. Type 1 brake system applies a strong automatic brake when a collision is very imminent. Type 2 brake system initiates brake operation softly when a rear-end crash may be anticipated. Types 1 and 2 are for avoidance of a collision. Type 3 brake system, on the other hand, applies a strong automatic brake to reduce the damage when a collision can not be avoided. An experiment was conducted with a driving simulator in order to analyze the driver's possible behavioral changes. The results showed that the time headway (THW) during car following phase was reduced by use of an automatic brake system of any type. The inverse of time to collision (TTC), which is an index of the driver's brake timing, increased by use of Type 1 brake system when the deceleration rate of the lead vehicle was relatively low. However, the brake timing did not change when the drivers used Type 2 or 3 brake system. As a whole, dangerous behavioral changes, such as overreliance on a brake system, were not observed for either type of brake system.

Texting while driving: is speech-based text entry less risky than handheld text entry?

Science.gov (United States)

He, J; Chaparro, A; Nguyen, B; Burge, R J; Crandall, J; Chaparro, B; Ni, R; Cao, S

2014-11-01

Research indicates that using a cell phone to talk or text while maneuvering a vehicle impairs driving performance. However, few published studies directly compare the distracting effects of texting using a hands-free (i.e., speech-based interface) versus handheld cell phone, which is an important issue for legislation, automotive interface design and driving safety training. This study compared the effect of speech-based versus handheld text entries on simulated driving performance by asking participants to perform a car following task while controlling the duration of a secondary text-entry task. Results showed that both speech-based and handheld text entries impaired driving performance relative to the drive-only condition by causing more variation in speed and lane position. Handheld text entry also increased the brake response time and increased variation in headway distance. Text entry using a speech-based cell phone was less detrimental to driving performance than handheld text entry. Nevertheless, the speech-based text entry task still significantly impaired driving compared to the drive-only condition. These results suggest that speech-based text entry disrupts driving, but reduces the level of performance interference compared to text entry with a handheld device. In addition, the difference in the distraction effect caused by speech-based and handheld text entry is not simply due to the difference in task duration. Copyright © 2014 Elsevier Ltd. All rights reserved.

An energy-efficient metro speed profiles for energy savings: application to the Valencia metro

Energy Technology Data Exchange (ETDEWEB)

Villalba Sanchis, I.; Salvador Zuriaga, P.

2016-07-01

Nowadays one of the main priorities for metro line operators is the reduction of energy consumption, due to the environmental impact and economic cost. In order to achieve this objective different strategies can be applied, normally focused into rolling stock, infrastructure and/or operation. Considering short-term measures and related to the traffic operation strategies, different approaches are being researched. One of the most effective strategy which reduce net energy consumption is the use of efficient driving techniques. These techniques produces a speed profile between two stations that requires the minimum net energy consumption, without degrading commercial running times or passenger comfort. In this paper, a computer model for calculating the metro vehicles speed profiles minimizing the energy consumption was developed. The equations considered in the model represent the behavior of a single vehicle operated under manual driving, subject to different constraints such as the headway, cycle time, distances and acceleration limits. The proposed model calculates different commands to be systematically executed by the driver. The resulting simulator has been tuned by means of on board measurements of speed, accelerations and energy consumption obtained along different lines in Metro de Valencia network. For this purpose, different scenarios are analyzed to assess the achievable energy savings. In general terms and comparing with the actual energy consumption, the solutions proposed can reduce the net energy consumption around 19%. (Author)

Different Control Algorithms for a Platoon of Autonomous Vehicles

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Zoran Gacovski

2014-05-01

Full Text Available This paper presents a concept of platoon movement of autonomous vehicles (smart cars. These vehicles have Adaptive or Advanced cruise control (ACC system also called Intelligent cruise control (ICC or Adaptive Intelligent cruise control (AICC system. The vehicles are suitable to follow other vehicles on desired distance and to be organized in platoons. To perform a research on the control and stability of an AGV (Automated Guided Vehicles string, we have developed a car-following model. To do this, first a single vehicle is modeled and since all cars in the platoon have the same dynamics, the single vehicle model is copied ten times to form model of platoon (string with ten vehicles. To control this string, we have applied equal PID controllers to all vehicles, except the leading vehicle. These controllers try to keep the headway distance as constant as possible and the velocity error between subsequent vehicles - small. For control of vehicle with nonlinear dynamics combi­nation of feedforward control and feedback control approach is used. Feedforward control is based on the inverse model of nominal dynamics of the vehicle, and feedback PID control is designed based on the linearized model of the vehicle. For simulation and analysis of vehicle and platoon of vehicles – we have developed Matlab/Simulink models. Simulation results, discussions and conclusions are given at the end of the paper.

Studying the Safety Impact of Autonomous Vehicles Using Simulation-Based Surrogate Safety Measures

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Mark Mario Morando

2018-01-01

Full Text Available Autonomous vehicle (AV technology has advanced rapidly in recent years with some automated features already available in vehicles on the market. AVs are expected to reduce traffic crashes as the majority of crashes are related to driver errors, fatigue, alcohol, or drugs. However, very little research has been conducted to estimate the safety impact of AVs. This paper aims to investigate the safety impacts of AVs using a simulation-based surrogate safety measure approach. To this end, safety impacts are explored through the number of conflicts extracted from the VISSIM traffic microsimulator using the Surrogate Safety Assessment Model (SSAM. Behaviours of human-driven vehicles (HVs and AVs (level 4 automation are modelled within the VISSIM’s car-following model. The safety investigation is conducted for two case studies, that is, a signalised intersection and a roundabout, under various AV penetration rates. Results suggest that AVs improve safety significantly with high penetration rates, even when they travel with shorter headways to improve road capacity and reduce delay. For the signalised intersection, AVs reduce the number of conflicts by 20% to 65% with the AV penetration rates of between 50% and 100% (statistically significant at p<0.05. For the roundabout, the number of conflicts is reduced by 29% to 64% with the 100% AV penetration rate (statistically significant at p<0.05.

Staying Connected on the Road: A Comparison of Different Types of Smart Phone Use in a Driving Simulator.

Science.gov (United States)

McNabb, Jaimie; Gray, Rob

2016-01-01

Previous research on smart phone use while driving has primarily focused on phone calls and texting. Drivers are now increasingly using their phone for other activities during driving, in particular social media, which have different cognitive demands. The present study compared the effects of four different smart phone tasks on car-following performance in a driving simulator. Phone tasks were chosen that vary across two factors: interaction medium (text vs image) and task pacing (self-paced vs experimenter-paced) and were as follows: Text messaging with the experimenter (text/other-paced), reading Facebook posts (text/self-paced), exchanging photos with the experimenter via Snapchat (image, experimenter-paced), and viewing updates on Instagram (image, experimenter-paced). Drivers also performed a driving only baseline. Brake reaction times (BRTs) were significantly greater in the text-based conditions (Mean = 1.16 s) as compared to both the image-based conditions (Mean = 0.92 s) and the baseline (0.88 s). There was no significant difference between BRTs in the image-based and baseline conditions and there was no significant effect of task-pacing. Similar results were obtained for Time Headway variability. These results are consistent with the picture superiority effect found in memory research and suggest that image-based interfaces could provide safer ways to "stay connected" while driving than text-based interfaces.

A Segmented Signal Progression Model for the Modern Streetcar System

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Baojie Wang

2015-01-01

Full Text Available This paper is on the purpose of developing a segmented signal progression model for modern streetcar system. The new method is presented with the following features: (1 the control concept is based on the assumption of only one streetcar line operating along an arterial under a constant headway and no bandwidth demand for streetcar system signal progression; (2 the control unit is defined as a coordinated intersection group associated with several streetcar stations, and the control joints must be streetcar stations; (3 the objective function is built to ensure the two-way streetcar arrival times distributing within the available time of streetcar phase; (4 the available time of streetcar phase is determined by timing schemes, intersection structures, track locations, streetcar speeds, and vehicular accelerations; (5 the streetcar running speed is constant separately whether it is in upstream or downstream route; (6 the streetcar dwell time is preset according to historical data distribution or charging demand. The proposed method is experimentally examined in Hexi New City Streetcar Project in Nanjing, China. In the experimental results, the streetcar system operation and the progression impacts are shown to affect transit and vehicular traffic. The proposed model presents promising outcomes through the design of streetcar system segmented signal progression, in terms of ensuring high streetcar system efficiency and minimizing negative impacts on transit and vehicular traffic.

Scientific developments of liquid crystal-based optical memory: a review

Science.gov (United States)

Prakash, Jai; Chandran, Achu; Biradar, Ashok M.

2017-01-01

The memory behavior in liquid crystals (LCs), although rarely observed, has made very significant headway over the past three decades since their discovery in nematic type LCs. It has gone from a mere scientific curiosity to application in variety of commodities. The memory element formed by numerous LCs have been protected by patents, and some commercialized, and used as compensation to non-volatile memory devices, and as memory in personal computers and digital cameras. They also have the low cost, large area, high speed, and high density memory needed for advanced computers and digital electronics. Short and long duration memory behavior for industrial applications have been obtained from several LC materials, and an LC memory with interesting features and applications has been demonstrated using numerous LCs. However, considerable challenges still exist in searching for highly efficient, stable, and long-lifespan materials and methods so that the development of useful memory devices is possible. This review focuses on the scientific and technological approach of fascinating applications of LC-based memory. We address the introduction, development status, novel design and engineering principles, and parameters of LC memory. We also address how the amalgamation of LCs could bring significant change/improvement in memory effects in the emerging field of nanotechnology, and the application of LC memory as the active component for futuristic and interesting memory devices.

Strength and behavior in shear of reinforced concrete deep beams under dynamic loading conditions

Energy Technology Data Exchange (ETDEWEB)

Adhikary, Satadru Das [School of Civil and Environmental Engineering, Nanyang Technological University, 639798 (Singapore); Li, Bing, E-mail: cbli@ntu.edu.sg [School of Civil and Environmental Engineering, Nanyang Technological University, 639798 (Singapore); Fujikake, Kazunori [Department of Civil and Environmental Engineering, National Defense Academy, Yokosuka 239 8686 (Japan)

2013-06-15

Highlights: ► Effects of wider range of loading rates on dynamic shear behavior of RC deep beams. ► Experimental investigation of RC deep beam with and without shear reinforcements. ► Verification of experimental results with truss model and FE simulation results. ► Empirical equations are proposed to predict the dynamic increase factor of maximum resistance. -- Abstract: Research on reinforced concrete (RC) deep beams has seen considerable headway over the past three decades; however, information on the dynamic shear strength and behavior of RC deep beams under varying rates of loads remains limited. This paper describes the experimental results of 24 RC deep beams with and without shear reinforcements under varying rates of concentrated loading. Results obtained serve as useful data on shear resistance, failure patterns and strain rates corresponding to varying loading rates. An analytical truss model approach proves its efficacy in predicting the dynamic shear resistance under varying loading rates. Furthermore, three-dimensional nonlinear finite element (FE) model is described and the simulation results are verified with the experimental results. A parametric study is then conducted to investigate the influence of longitudinal reinforcement ratio, transverse reinforcement ratio and shear span to effective depth ratio on shear behavior. Subsequently, two empirical equations were proposed by integrating the various parameters to assess the dynamic increase factor (DIF) of maximum resistance under varying rates of concentrated loading.

A country on the verge of malaria elimination--the Kingdom of Saudi Arabia.

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Michael Coleman

Full Text Available Significant headway has been made in the global fight against malaria in the past decade and as more countries enter the elimination phase, attention is now focused on identifying effective strategies to shrink the malaria map. Saudi Arabia experienced an outbreak of malaria in 1998, but is now on the brink of malaria elimination, with just 82 autochthonous cases reported in 2012. A review of published and grey literature was performed to identify the control strategies that have contributed to this achievement. The number of autochthonous malaria cases in Saudi Arabia decreased by 99.8% between 1998 and 2012. The initial steep decline in malaria cases coincided with a rapid scaling up of vector control measures. Incidence continued to be reported at low levels (between 0.01 and 0.1 per 1,000 of the population until the adoption of artesunate plus sulfadoxine-pyrimethamine as first line treatment and the establishment of a regional partnership for a malaria-free Arabian Peninsula, both of which occurred in 2007. Since 2007, incidence has decreased by nearly an order of magnitude. Malaria incidence is now very low, but a high proportion of imported cases, continued potential for autochthonous transmission, and an increased proportion of cases attributable to Plasmodium vivax all present challenges to Saudi Arabia as they work toward elimination by 2015.

Laser Processed Silver Nanowire Network Transparent Electrodes for Novel Electronic Devices

Science.gov (United States)

Spechler, Joshua Allen

Silver nanowire network transparent conducting layers are poised to make headway into a space previously dominated by transparent conducting oxides due to the promise of a flexible, scaleable, lab-atmosphere processable alternative. However, there are many challenges standing in the way between research scale use and consumer technology scale adaptation of this technology. In this thesis we will explore many, and overcome a few of these challenges. We will address the poor conductivity at the narrow nanowire-nanowire junction points in the network by developing a laser based process to weld nanowires together on a microscopic scale. We address the need for a comparative metric for transparent conductors in general, by taking a device level rather than a component level view of these layers. We also address the mechanical, physical, and thermal limitations to the silver nanowire networks by making composites from materials including a colorless polyimide and titania sol-gel. Additionally, we verify our findings by integrating these processes into devices. Studying a hybrid organic/inorganic heterojunction photovoltaic device we show the benefits of a laser processed electrode. Green phosphorescent organic light emitting diodes fabricated on a solution phase processed silver nanowire based electrode show favorable device metrics compared to a conductive oxide electrode based control. The work in this thesis is intended to push the adoption of silver nanowire networks to further allow new device architectures, and thereby new device applications.

Discovery of a novel site of opioid action at the innate immune pattern-recognition receptor TLR4 and its role in addiction.

Science.gov (United States)

Jacobsen, Jonathan Henry W; Watkins, Linda R; Hutchinson, Mark R

2014-01-01

Opioids have historically, and continue to be, an integral component of pain management. However, despite pharmacokinetic and dynamic optimization over the past 100 years, opioids continue to produce many undesirable side effects such as tolerance, reward, and dependence. As such, opioids are liable for addiction. Traditionally, opioid addiction was viewed as a solely neuronal process, and while substantial headway has been made into understanding the molecular and cellular mechanisms mediating this process, research has however, been relatively ambivalent to how the rest of the central nervous system (CNS) responds to opioids. Evidence over the past 20 years has clearly demonstrated the importance of the immunocompetent cells of the CNS (glia) in many aspects of opioid pharmacology. Particular focus has been placed on microglia and astrocytes, who in response to opioids, become activated and release inflammatory mediators. Importantly, the mechanism underlying immune activation is beginning to be elucidated. Evidence suggests an innate immune pattern-recognition receptor (toll-like receptor 4) as an integral component underlying opioid-induced glial activation. The subsequent proinflammatory response may be viewed akin to neurotransmission creating a process termed central immune signaling. Translationally, we are beginning to appreciate the importance of central immune signaling as it contributes to many behavioral actions of addiction including reward, withdrawal, and craving. As such, the aim of this chapter is to review and integrate the neuronal and central immune signaling perspective of addiction. © 2014 Elsevier Inc. All rights reserved.

Metabolic cartography: experimental quantification of metabolic fluxes from isotopic labelling studies.

Science.gov (United States)

O'Grady, John; Schwender, Jörg; Shachar-Hill, Yair; Morgan, John A

2012-03-01

For the past decade, flux maps have provided researchers with an in-depth perspective on plant metabolism. As a rapidly developing field, significant headway has been made recently in computation, experimentation, and overall understanding of metabolic flux analysis. These advances are particularly applicable to the study of plant metabolism. New dynamic computational methods such as non-stationary metabolic flux analysis are finding their place in the toolbox of metabolic engineering, allowing more organisms to be studied and decreasing the time necessary for experimentation, thereby opening new avenues by which to explore the vast diversity of plant metabolism. Also, improved methods of metabolite detection and measurement have been developed, enabling increasingly greater resolution of flux measurements and the analysis of a greater number of the multitude of plant metabolic pathways. Methods to deconvolute organelle-specific metabolism are employed with increasing effectiveness, elucidating the compartmental specificity inherent in plant metabolism. Advances in metabolite measurements have also enabled new types of experiments, such as the calculation of metabolic fluxes based on (13)CO(2) dynamic labelling data, and will continue to direct plant metabolic engineering. Newly calculated metabolic flux maps reveal surprising and useful information about plant metabolism, guiding future genetic engineering of crops to higher yields. Due to the significant level of complexity in plants, these methods in combination with other systems biology measurements are necessary to guide plant metabolic engineering in the future.

Linking mind wandering tendency to risky driving in young male drivers.

Science.gov (United States)

Albert, Derek A; Ouimet, Marie Claude; Jarret, Julien; Cloutier, Marie-Soleil; Paquette, Martin; Badeau, Nancy; Brown, Thomas G

2018-02-01

Risky driving is a significant contributor to road traffic crashes, especially in young drivers. Transient mind wandering states, an internal form of distraction, are associated with faster driving, reduced headway distance, slower response times, reduced driver vigilance, and increased crash risk. It is unclear whether a trait tendency to mind wander predicts risky driving, however. Mind wandering is also associated with poor executive control, but whether this capacity moderates the putative link between mind wandering tendency and risky driving is uncertain. The present study tested whether mind wandering tendency predicts risky driving behaviour in young male drivers aged 18-21 (N=30) and whether this relationship is mediated by driver vigilance and moderated by executive control capacity. Mind wandering was measured with the Sustained Attention to Response Task (SART) and the Daydreaming Frequency Scale (DDFS). Risky driving was assessed by mean speed in a driving simulator and driver vigilance was quantified by horizontal eye movements measured with eye tracking. Results showed that greater mind wandering tendency based on SART performance significantly predicts faster mean speed, confirming the main hypothesis. Neither driver vigilance mediated nor executive control capacity moderated this relationship as hypothesized. These findings speak to the complexity of individual differences in mind wandering. Overall, mind wandering tendency is a significant marker of risky driving in young drivers, which could guide the development of targeted interventions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Transgenerational and developmental plasticity at the molecular level: Lessons from Daphnia.

Science.gov (United States)

Bell, Alison M; Stein, Laura R

2017-10-01

Listen to the news and you are bound to hear that researchers are increasingly interested in the biological manifestations of trauma that reverberate through the generations. Research in this area can be controversial in the public realm, provoking societal issues about personal responsibility (are we really born free or are we born with the burden of our ancestors' experience?). It is also a touchy subject within evolutionary biology because it provokes concerns about Lamarckianism and general scepticism about the importance of extra-genetic inheritance (Laland et al., ). Part of why the research in this area has been controversial is because it is difficult to study. For one, there is the problem of how long it takes to track changes across generations, making long-term, multi-generational studies especially tricky in long-lived species. Moreover, there are presently very few (if any) known molecular mechanisms by which environmental effects can be incorporated into the genome and persist for multiple successive generations, casting doubt on their evolutionary repercussions. Fortunately, you only have to look in your local pond to find the creatures that are teaching us a great deal about how and why the experiences of parents are passed down to their offspring. In this issue of Molecular Ecology, Hales et al. (Hales et al., ) illustrate the power of Daphnia ("water fleas") for making headway in this field. © 2017 John Wiley & Sons Ltd.

PERENCANAAN SISTEM OPERASIONAL ANGKUTAN WISATA DI KOTA DENPASAR

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Dyah Ayu Lesatri

2017-01-01

Full Text Available Abstract: Tourism is the main sector for the economy of Bali. Denpasar City as the capital city of Bali Province is expected to maintain its position as one of main tourist destinations by increasing and improving existing tourism facilities, and one of them with the provision of tourism transport that serving tourists heading into tourism attraction in the city of Denpasar. The purposes of this research are to analyze the potential demand, tourism transport route and the characteristic of operational system of tourism transport in Denpasar City. From the analysis that has been done, it is obtained that the potential demand of tourist transport in Denpasar City is 438.576 people in 2013 and it is estimated to be 485.998 in 2017. The highest number of tourist those visit the attraction places through the routes of : Belanjong Pillar, Serangan Island, Central Management of Mangrove Forest, The Village of Budaya Kertalangu, Taman Budaya Art Centre, Museum Painting Fingerprint, Bajra Sandhi Monument, Kumbasari Market, Badung Market, Bali Museum.  Alternatives tour packages include regular tour packages with 10 attractions, regular city tours, regular nature tours, city tour charters, and natural attraction charters. Tourist transports operate using medium buses and minibus for 8 hours service time from 09.00 am until 17.00 pm for regular and 4,5 hours until 5,5 hours for charter package. The headway is set 30 minutes.

Life cycle considerations for improving sustainability assessments in seafood awareness campaigns.

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Pelletier, Nathan; Tyedmers, Peter

2008-11-01

It is widely accepted that improving the sustainability of seafood production requires efforts to reverse declines in global fisheries due to overfishing and to reduce the impacts to host ecosystems from fishing and aquaculture production technologies. Reflective of on-going dialogue amongst participants in an international research project applying Life Cycle Assessment to better understand and manage global salmon production systems, we argue here that such efforts must also address the wider range of biophysical, ecological, and socioeconomic impacts stemming from the material and energetic throughput associated with these industries. This is of particular relevance given the interconnectivity of global environmental change, ocean health, and the viability of seafood production in both fisheries and aquaculture. Although the growing popularity of numerous ecolabeling, certification, and consumer education programs may be making headway in influencing Western consumer perceptions of the relative sustainability of alternative seafood products, we also posit that the efficacy of these initiatives in furthering sustainability objectives is compromised by the use of incomplete criteria. An emerging body of Life Cycle Assessment research of fisheries and aquaculture provides valuable insights into the biophysical dimensions of environmental performance in alternative seafood production and consumption systems, and should be used to inform a more holistic approach to labeling, certifying, and educating for sustainability in seafood production. More research, however, must be undertaken to develop novel techniques for incorporating other critical dimensions, in particular, socioeconomic considerations, into our sustainability decision-making.

Demand estimation of bus as a public transport based on gravity model

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Asmael Noor

2018-01-01

Full Text Available Bus as a public transport is a suitable service to meet the travel demand between any two zones. Baghdad faced with severe traffic problems along with the development in city size and economy. Passengers have to wait lots of time during commutation to work because of the serious traffic jams. In the last years, rate of car ownership has increased as income levels have gone up and cars have become a preferable mode of transport. Bus, as the only public mode of transport available, is suffering from inconvenience, slowness, and inflexibility. A big emphasis must be given to the public transport system because it introduces an active utilization of limited resources, energy and land. This study determines the demand of public routes for buses using boarding / alighting values to generate a model and assign these demand values to the bus network. Five public routes were selected to collect the required data. Ride check and Point check survey was conducted for each selected route. The results of this study were public demand assigned to the selected bus routes, dwell time, load factor and headway. It is observed that R1 and R3 have the heaviest travel demand; they need special study to improve bus performance and make better transit. The model developed with only limited data available to predict travel demand will assist transportation planners and related agencies in decision making.

Effect of resource conserving techniques on crop productivity in rice-wheat cropping system

International Nuclear Information System (INIS)

Mann, R.A.; Munir, M.; Haqqani, A.M.

2004-01-01

Rice-wheat cropping system is the most important one in Pakistan. The system provides food and livelihood for more than 15 million people in the country. The productivity of the system is much lower than the potential yields of both rice and wheat crops. With the traditional methods, rice-wheat system is not a profitable one to many farmers. Hence, Cost of cultivation must be reduced and at the same time, efficiency of resources like irrigation water, fuel, and fertilizers must be improved to make the crop production system more viable and eco- friendly. Resource conserving technology (RCT) must figure highly in this equation, since they play a major role in achieving the above goals. The RCT include laser land leveling, zero-tillage, bed furrow irrigation method and crop residue management. These technologies were evaluated in irrigated areas of Punjab where rice follows wheat. The results showed that paddy yield was not affected by the new methods. Direct seeding of rice crop saved irrigation water by 13% over the conventionally planted crop. Weeds were the major problem indirect seeded crop, which could be eliminated through cultural, mechanical and chemical means. Wheat crop on beds produced the highest yield but cost of production was minimum in the zero-till wheat crop. Planting of wheat on raised beds in making headway in low- lying and poorly drained areas. Thus, resource conserving tillage technology provides a tool for making progress towards improving and sustaining wheat production system, helping with food security and poverty alleviation in Pakistan in the next few decades. (author)

Knowledge Gaps in Rodent Pancreas Biology: Taking Human Pluripotent Stem Cell-Derived Pancreatic Beta Cells into Our Own Hands.

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Santosa, Munirah Mohamad; Low, Blaise Su Jun; Pek, Nicole Min Qian; Teo, Adrian Kee Keong

2015-01-01

In the field of stem cell biology and diabetes, we and others seek to derive mature and functional human pancreatic β cells for disease modeling and cell replacement therapy. Traditionally, knowledge gathered from rodents is extended to human pancreas developmental biology research involving human pluripotent stem cells (hPSCs). While much has been learnt from rodent pancreas biology in the early steps toward Pdx1(+) pancreatic progenitors, much less is known about the transition toward Ngn3(+) pancreatic endocrine progenitors. Essentially, the later steps of pancreatic β cell development and maturation remain elusive to date. As a result, the most recent advances in the stem cell and diabetes field have relied upon combinatorial testing of numerous growth factors and chemical compounds in an arbitrary trial-and-error fashion to derive mature and functional human pancreatic β cells from hPSCs. Although this hit-or-miss approach appears to have made some headway in maturing human pancreatic β cells in vitro, its underlying biology is vaguely understood. Therefore, in this mini-review, we discuss some of these late-stage signaling pathways that are involved in human pancreatic β cell differentiation and highlight our current understanding of their relevance in rodent pancreas biology. Our efforts here unravel several novel signaling pathways that can be further studied to shed light on unexplored aspects of rodent pancreas biology. New investigations into these signaling pathways are expected to advance our knowledge in human pancreas developmental biology and to aid in the translation of stem cell biology in the context of diabetes treatments.

Family Health Services project: the way forward.

Science.gov (United States)

Dabiri, O M

1993-01-01

Nigerians did not readily accept family planning when Family Health Services (FHS) began in 1988. FHS has made much headway in training, IEC (information, education, and communication), and constituency building and advocacy. Its staff have identified obstacles to implementation, especially program sustainability and management structure. Key limits to sustainability of IEC efforts were inadequately trained personnel and inability of trained personnel to apply what they learned at work stations. The Federal Ministry and Social Services' role in the FHS project was not clearly defined. Some private sector factors contributing to a confused management structure were inadequate method mix, high contraceptive cost, poor monitoring of quality of care, and no coordination of family planning training with the public factor. FHS has since decided to focus its efforts on increasing the demand for and availability of modern contraceptives and improving the quality of family planning services of both the public and private sectors. FHS hopes that accomplishing these activities will reduce fertility, morbidity, and mortality. Strategic plans include a regional focus, quality of care, a variety of methods offered, intensification, hospital and clinics, a management information system, contraceptive logistics, distribution regulations, and addressing social, cultural, and behavioral factors. To effectively implement the strategy, USAID and the Federal Ministry held a workshop in 1993 to effect full integration of Nigerian experience in the 2nd phase of the project (FHS II). Participants reviewed the strengths and weaknesses of the first phase and agreed on implementation. For example, nongovernmental organizations should implement FHS II. FHS II includes training, IEC, and commodities/logistics.

Augmented Reality Cues and Elderly Driver Hazard Perception

Science.gov (United States)

Schall, Mark C.; Rusch, Michelle L.; Lee, John D.; Dawson, Jeffrey D.; Thomas, Geb; Aksan, Nazan; Rizzo, Matthew

2013-01-01

Objective Evaluate the effectiveness of augmented reality (AR) cues in improving driving safety in elderly drivers who are at increased crash risk due to cognitive impairments. Background Cognitively challenging driving environments pose a particular crash risk for elderly drivers. AR cueing is a promising technology to mitigate risk by directing driver attention to roadway hazards. This study investigates whether AR cues improve or interfere with hazard perception in elderly drivers with age-related cognitive decline. Methods Twenty elderly (Mean= 73 years, SD= 5 years), licensed drivers with a range of cognitive abilities measured by a speed of processing (SOP) composite participated in a one-hour drive in an interactive, fixed-base driving simulator. Each participant drove through six, straight, six-mile-long rural roadway scenarios following a lead vehicle. AR cues directed attention to potential roadside hazards in three of the scenarios, and the other three were uncued (baseline) drives. Effects of AR cueing were evaluated with respect to: 1) detection of hazardous target objects, 2) interference with detecting nonhazardous secondary objects, and 3) impairment in maintaining safe distance behind a lead vehicle. Results AR cueing improved the detection of hazardous target objects of low visibility. AR cues did not interfere with detection of nonhazardous secondary objects and did not impair ability to maintain safe distance behind a lead vehicle. SOP capacity did not moderate those effects. Conclusion AR cues show promise for improving elderly driver safety by increasing hazard detection likelihood without interfering with other driving tasks such as maintaining safe headway. PMID:23829037

Ecological aspects of radiation protection

Energy Technology Data Exchange (ETDEWEB)

Recht, P [Health Protection Services, Commission of the European Communities, Brussels (Belgium); Free University, Brussels (Belgium)

1972-07-01

For the ecologists of the 1960s, the presence in the biosphere of fission products originating from nuclear explosions provided a wealth of opportunity for observation and experiment, for they were able to trace the paths of numerous radioactive substances in the atmosphere, immediate environment and eco-systems, and to determine the way in which these substances were metabolized in living organisms. Moreover, nuclear techniques such as the use of radioactive tracers, autoradiography and neutron activation afforded a means of determining the mechanisms by which the biologically significant radionuclides take effect and the processes by which they are transferred. Because of the comprehensive information that it can provide for analysis, radioecology has risen above its status as a pure science and has become an integral part in the planning of monitoring programmes for nuclear sites- Radioecology is thereby able to make an essential contribution to the attainment of one of the basic objectives of radiation protection, namely the elimination or control of the hazards that human beings and their environment are likely to be face through the peaceful applications of nuclear energy. The headway made in radioecological studies and research has been great; knowledge is being amassed by leaps and bounds despite the difficulties faced and the intricacy of the problems involved. As a consequence, radioactive contamination of the environment is certainly one of the best understood types of pollution, and probably one that it has so far been possible to anticipate and control under optimum conditions and with the most gratifying results.

Development of the nervus terminalis: origin and migration.

Science.gov (United States)

Whitlock, Kathleen E

2004-09-01

The origin of the nervus terminalis is one of the least well understood developmental events involved in generating the cranial ganglia of the forebrain in vertebrate animals. This cranial nerve forms at the formidable interface of the anteriormost limits of migrating cranial neural crest cells, the terminal end of the neural tube and the differentiating olfactory and adenohypophyseal placodes. The complex cellular interactions that give rise to the various structures associated with the sensory placode (olfactory) and endocrine placode (adenohypophysis) surround and engulf this enigmatic cranial nerve. The tortured history of nervus terminalis development (see von Bartheld, this issue, pages 13-24) reflects the lack of consensus on the origin (or origins), as well as the experimental difficulties in uncovering the origin, of the nervus terminalis. Recent technical advances have allowed us to make headway in understanding the origin(s) of this nerve. The emergence of the externally fertilized zebrafish embryo as a model system for developmental biology and genetics has shed new light on this century-old problem. Coupled with new developmental models are techniques that allow us to trace lineage, visualize gene expression, and genetically ablate cells, adding to our experimental tools with which to follow up on studies provided by our scientific predecessors. Through these techniques, a picture is emerging in which the origin of at least a subset of the nervus terminalis cells lies in the cranial neural crest. In this review, the data surrounding this finding will be discussed in light of recent findings on neural crest and placode origins. Copyright 2004 Wiley-Liss, Inc.

Ecological aspects of radiation protection

International Nuclear Information System (INIS)

Recht, P.

1972-01-01

For the ecologists of the 1960s, the presence in the biosphere of fission products originating from nuclear explosions provided a wealth of opportunity for observation and experiment, for they were able to trace the paths of numerous radioactive substances in the atmosphere, immediate environment and eco-systems, and to determine the way in which these substances were metabolized in living organisms. Moreover, nuclear techniques such as the use of radioactive tracers, autoradiography and neutron activation afforded a means of determining the mechanisms by which the biologically significant radionuclides take effect and the processes by which they are transferred. Because of the comprehensive information that it can provide for analysis, radioecology has risen above its status as a pure science and has become an integral part in the planning of monitoring programmes for nuclear sites- Radioecology is thereby able to make an essential contribution to the attainment of one of the basic objectives of radiation protection, namely the elimination or control of the hazards that human beings and their environment are likely to be face through the peaceful applications of nuclear energy. The headway made in radioecological studies and research has been great; knowledge is being amassed by leaps and bounds despite the difficulties faced and the intricacy of the problems involved. As a consequence, radioactive contamination of the environment is certainly one of the best understood types of pollution, and probably one that it has so far been possible to anticipate and control under optimum conditions and with the most gratifying results

Criterion for traffic phases in single vehicle data and empirical test of a microscopic three-phase traffic theory

International Nuclear Information System (INIS)

Kerner, Boris S; Klenov, Sergey L; Hiller, Andreas

2006-01-01

Based on empirical and numerical microscopic analyses, the physical nature of a qualitatively different behaviour of the wide moving jam phase in comparison with the synchronized flow phase-microscopic traffic flow interruption within the wide moving jam phase-is found. A microscopic criterion for distinguishing the synchronized flow and wide moving jam phases in single vehicle data measured at a single freeway location is presented. Based on this criterion, empirical microscopic classification of different local congested traffic states is performed. Simulations made show that the microscopic criterion and macroscopic spatiotemporal objective criteria lead to the same identification of the synchronized flow and wide moving jam phases in congested traffic. Microscopic models in the context of three-phase traffic theory have been tested based on the microscopic criterion for the phases in congested traffic. It is found that microscopic three-phase traffic models can explain both microscopic and macroscopic empirical congested pattern features. It is obtained that microscopic frequency distributions for vehicle speed difference as well as fundamental diagrams and speed correlation functions can depend on the spatial co-ordinate considerably. It turns out that microscopic optimal velocity (OV) functions and time headway distributions are not necessarily qualitatively different, even if local congested traffic states are qualitatively different. The reason for this is that important spatiotemporal features of congested traffic patterns are lost in these as well as in many other macroscopic and microscopic traffic characteristics, which are widely used as the empirical basis for a test of traffic flow models, specifically, cellular automata traffic flow models

Tradeoffs between costs and greenhouse gas emissions in the design of urban transit systems

International Nuclear Information System (INIS)

Griswold, Julia B; Madanat, Samer; Horvath, Arpad

2013-01-01

Recent investments in the transit sector to address greenhouse gas emissions have concentrated on purchasing efficient replacement vehicles and inducing mode shift from the private automobile. There has been little focus on the potential of network and operational improvements, such as changes in headways, route spacing, and stop spacing, to reduce transit emissions. Most models of transit system design consider user and agency cost while ignoring emissions and the potential environmental benefit of operational improvements. We use a model to evaluate the user and agency costs as well as greenhouse gas benefit of design and operational improvements to transit systems. We examine how the operational characteristics of urban transit systems affect both costs and greenhouse gas emissions. The research identifies the Pareto frontier for designing an idealized transit network. Modes considered include bus, bus rapid transit (BRT), light rail transit (LRT), and metro (heavy) rail, with cost and emissions parameters appropriate for the United States. Passenger demand follows a many-to-many travel pattern with uniformly distributed origins and destinations. The approaches described could be used to optimize the network design of existing bus service or help to select a mode and design attributes for a new transit system. The results show that BRT provides the lowest cost but not the lowest emissions for our large city scenarios. Bus and LRT systems have low costs and the lowest emissions for our small city scenarios. Relatively large reductions in emissions from the cost-optimal system can be achieved with only minor increases in user travel time. (letter)

From Fireproof Desert to Flammable Grassland: Buffelgrass Invasion in the Sonoran Desert

Science.gov (United States)

Betancourt, J. L.

2007-12-01

Only a few decades ago, the Sonoran Desert of northwestern Mexico and southern Arizona was considered mostly fireproof, a case of not enough fine fuel to connect the dominant shrubs and cacti. This has changed with invasions by non-native, winter annual and summer-flower perennial grasses that are rapidly transforming fireproof desert into flammable grassland. Of particular concern is buffelgrass, Pennisetum ciliare, a fire-prone and invasive African perennial grass that has already converted millions of hectares across Sonora since the mid-1960s and has made quick headway in southern and central Arizona beginning in the 1980s. Near Tucson and Phoenix, AZ, buffelgrass invasion is proceeding exponentially, with population expansion (and the costs of mitigation) more than doubling every year. As this conversion progresses, there will be increased fire risks, lost tourist revenue, diminished property values, insurmountable setbacks to conservation efforts, and the threat of large ignition fronts in desert valleys routinely spreading into the mountains. Although somewhat belated, an integrated, multi-jurisdictional effort is being organized to reduce ecological and economic impacts. My presentation will summarize the history and context of buffelgrass introduction and invasion, the disconnect in attitudes and policies across state and international boundaries, ongoing management efforts, the role of science and responsibilities of scientists, accelerated spread with changing climate, and impacts to regional ecosystems and economies. This narrative may serve as a template for other semi-arid lands where buffelgrass and similar grasses have become invasive, including Australia, South America, and many islands in the Pacific Ocean (including Hawaii), Indian Ocean, and Caribbean Sea.

Physics of correlated studies. Final report, September 1, 1990--November 30, 1993

International Nuclear Information System (INIS)

Greene, C.H.

1993-01-01

During the three year period of this grant, a major initiative was started to develop theoretical methods to treat complex open-shell atoms in a manner permitting a simple interpretation of the dynamics. This project has been far more successful than originally hoped, with accurate ground state photoionization cross sections calculated for nine different open-shell atoms in the periodic table. This work culminated in our first application to multichannel autoionizing spectra of a transition metal atom, scandium. These methods were also extended and adapted to permit a description of nonresonant two-photon processes at the perturbative level, and some nonperturbative multiphoton processes. The angular distribution of photoelectrons ejected in resonant multiphoton ionization of magnesium was also successfully calculated. We made headway toward understanding aspects of the diamagnetic quasi-Landau problem, specifically interpreting the observed simplicity of the spectrum when plotted simultaneously versus energy and field. High two-electron excitations of H - and Li - were treated using R-matrix methods, combined with a time delay analysis to quantitatively test various propensity rules proposed in the literature. These calculations also gave the first accurate description of H - experiments at Los Alamos, up to the n = 6 threshold. A new set of computer programs were developed to handle double-Rydberg ''planetary'' states of barium and strontium, incorporating long range multipole interactions explicitly. Finally, we studied triply-excited states of H -- in an attempt to clarify the question of whether such resonances exist. Each of these projects is described in greater detail below

The unipolar ASR : Viable option in unsalvageable femoral head conditions in the young patient

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Marya SKS

2006-01-01

Full Text Available Background: The management of unsalvageable femoral head conditions in the young patient has remained an unresolved dilemma. Articular surface replacement of the hip has recently made some headway in terms of providing near-normal hip joint mechanics and function. However, this surgery has been limited to early stages of arthritis only with reasonable maintenance of head-neck congruity and morphology. Femoral neck fractures, osteonecrosis with large segment collapse, advanced arthritis with femoral incongruity, etc are traditional contraindications to the resurfacing technique. Methods: We present here a report on our series of 20 cases of unsalvageable femoral heads in young patients (age range, 27 to 52yrs, over a twelve month period (Aug 2004 to Jul 2005, treated with the unipolar ASR prosthesis. Fifteen patients (two had bilateral hip pathology had primary or secondary arthritis (degenerative, post-traumatic, ankylosing spondylitis and post-avascular necrosis while three had old operated femoral neck fractures. All patients underwent hip replacement surgery using the Unipolar ASR prosthesis. Results: Clinical and radiological results at 6-month follow up have been very encouraging and warrant further study. At an average of 4 months post-operatively, patients were able to squat, sit on the ground and perform light sporting activities. Conclusions: The Unipolar ASR prosthesis is an extension of the articular resurfacing technique employing similar principles (large size bearings, metal-on-metal interfaces, and has incorporated the advantages of the uncemented technique. We propose that this technique be more frequently used so as to brighten the prognosis of the young active patient with unsalvageable hip conditions, especially in the Asian scenario.

The epidemiology of road traffic injury hotspots in Kigali, Rwanda from police data

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Anjni Patel

2016-08-01

Full Text Available Abstract Background Road traffic injuries (RTIs are the eighth-leading cause of death worldwide, with low- and middle-income countries sharing a disproportionate number of fatalities. African countries, like Rwanda, carry a higher burden of these fatalities and with increased economic growth, these numbers are expected to rise. We aim to describe the epidemiology of RTIs in Kigali Province, Rwanda and create a hotspot map of crashes from police data. Methods Road traffic crash (RTC report data from January 1, 2013 to December 31, 2013 was collected from Kigali Traffic Police. In addition to analysis of descriptive data, locations of RTCs were mapped and analyzed through exploratory spatial data analysis to determine hotspots. Results A total of 2589 of RTCs were reported with 4689 total victims. The majority of victims were male (94.7 % with an average age of 35.9 years. Cars were the most frequent vehicle involved (43.8 %, followed by motorcycles (14.5 %. Motorcycles had an increased risk of involvement in grievous crashes and pedestrians and cyclists were more likely to have grievous injuries. The hotspots identified were primarily located along the major roads crossing Kigali and the two busiest downtown areas. Conclusions Despite significant headway by the government in RTC prevention, there continue to be high rates of RTIs in Rwanda, specifically with young males and a vulnerable road user population, such as pedestrians and motorcycle users. Improvements in police data and reporting by laypersons could prove valuable for further geographic information system analysis and efforts towards crash prevention and targeting education to motorcycle taxis could help reduce RTIs in a severely affected population.

The epidemiology of road traffic injury hotspots in Kigali, Rwanda from police data.

Science.gov (United States)

Patel, Anjni; Krebs, Elizabeth; Andrade, Luciano; Rulisa, Stephen; Vissoci, João Ricardo N; Staton, Catherine A

2016-08-02

Road traffic injuries (RTIs) are the eighth-leading cause of death worldwide, with low- and middle-income countries sharing a disproportionate number of fatalities. African countries, like Rwanda, carry a higher burden of these fatalities and with increased economic growth, these numbers are expected to rise. We aim to describe the epidemiology of RTIs in Kigali Province, Rwanda and create a hotspot map of crashes from police data. Road traffic crash (RTC) report data from January 1, 2013 to December 31, 2013 was collected from Kigali Traffic Police. In addition to analysis of descriptive data, locations of RTCs were mapped and analyzed through exploratory spatial data analysis to determine hotspots. A total of 2589 of RTCs were reported with 4689 total victims. The majority of victims were male (94.7 %) with an average age of 35.9 years. Cars were the most frequent vehicle involved (43.8 %), followed by motorcycles (14.5 %). Motorcycles had an increased risk of involvement in grievous crashes and pedestrians and cyclists were more likely to have grievous injuries. The hotspots identified were primarily located along the major roads crossing Kigali and the two busiest downtown areas. Despite significant headway by the government in RTC prevention, there continue to be high rates of RTIs in Rwanda, specifically with young males and a vulnerable road user population, such as pedestrians and motorcycle users. Improvements in police data and reporting by laypersons could prove valuable for further geographic information system analysis and efforts towards crash prevention and targeting education to motorcycle taxis could help reduce RTIs in a severely affected population.

Drivers anticipate lead-vehicle conflicts during automated longitudinal control: Sensory cues capture driver attention and promote appropriate and timely responses.

Science.gov (United States)

Morando, Alberto; Victor, Trent; Dozza, Marco

2016-12-01

Adaptive Cruise Control (ACC) has been shown to reduce the exposure to critical situations by maintaining a safe speed and headway. It has also been shown that drivers adapt their visual behavior in response to the driving task demand with ACC, anticipating an impending lead vehicle conflict by directing their eyes to the forward path before a situation becomes critical. The purpose of this paper is to identify the causes related to this anticipatory mechanism, by investigating drivers' visual behavior while driving with ACC when a potential critical situation is encountered, identified as a forward collision warning (FCW) onset (including false positive warnings). This paper discusses how sensory cues capture attention to the forward path in anticipation of the FCW onset. The analysis used the naturalistic database EuroFOT to examine visual behavior with respect to two manually-coded metrics, glance location and glance eccentricity, and then related the findings to vehicle data (such as speed, acceleration, and radar information). Three sensory cues (longitudinal deceleration, looming, and brake lights) were found to be relevant for capturing driver attention and increase glances to the forward path in anticipation of the threat; the deceleration cue seems to be dominant. The results also show that the FCW acts as an effective attention-orienting mechanism when no threat anticipation is present. These findings, relevant to the study of automation, provide additional information about drivers' response to potential lead-vehicle conflicts when longitudinal control is automated. Moreover, these results suggest that sensory cues are important for alerting drivers to an impending critical situation, allowing for a prompt reaction. Copyright © 2016 Elsevier Ltd. All rights reserved.

Forest Ecosystem Services and Eco-Compensation Mechanisms in China

Science.gov (United States)

Deng, Hongbing; Zheng, Peng; Liu, Tianxing; Liu, Xin

2011-12-01

Forests are a major terrestrial ecosystem providing multiple ecosystem services. However, the importance of forests is frequently underestimated from an economic perspective because of the externalities and public good properties of these services. Forest eco-compensation is a transfer mechanism that serves to internalize the externalities of forest ecosystem services by compensating individuals or companies for the losses or costs resulting from the provision of these services. China's current forest eco-compensation system is centered mainly on noncommercial forest. The primary measures associated with ecosystem services are (1) a charge on destructive activities, such as indiscriminate logging, and (2) compensation for individual or local activities and investments in forest conservation. The Compensation Fund System for Forest Ecological Benefits was first listed in the Forest Law of the People's Republic of China in 1998. In 2004, the Central Government Financial Compensation Fund, an important source for the Compensation Fund for Forest Ecological Benefits, was formally established. To improve the forest eco-compensation system, it is crucial to design and establish compensation criteria for noncommercial forests. These criteria should take both theoretical and practical concerns into account, and they should be based on the quantitative valuation of ecosystem services. Although some initial headway has been made on this task, the implementation of an effective forest eco-compensation system in China still has deficiencies and still faces problems. Implementing classification-based and dynamic management for key noncommercial forests and establishing an eco-compensation mechanism with multiple funding sources in the market economy are the key measures needed to conquer these problems and improve the forest eco-compensation system and China's forestry development in sequence.

Forest ecosystem services and eco-compensation mechanisms in China.

Science.gov (United States)

Deng, Hongbing; Zheng, Peng; Liu, Tianxing; Liu, Xin

2011-12-01

Forests are a major terrestrial ecosystem providing multiple ecosystem services. However, the importance of forests is frequently underestimated from an economic perspective because of the externalities and public good properties of these services. Forest eco-compensation is a transfer mechanism that serves to internalize the externalities of forest ecosystem services by compensating individuals or companies for the losses or costs resulting from the provision of these services. China's current forest eco-compensation system is centered mainly on noncommercial forest. The primary measures associated with ecosystem services are (1) a charge on destructive activities, such as indiscriminate logging, and (2) compensation for individual or local activities and investments in forest conservation. The Compensation Fund System for Forest Ecological Benefits was first listed in the Forest Law of the People's Republic of China in 1998. In 2004, the Central Government Financial Compensation Fund, an important source for the Compensation Fund for Forest Ecological Benefits, was formally established. To improve the forest eco-compensation system, it is crucial to design and establish compensation criteria for noncommercial forests. These criteria should take both theoretical and practical concerns into account, and they should be based on the quantitative valuation of ecosystem services. Although some initial headway has been made on this task, the implementation of an effective forest eco-compensation system in China still has deficiencies and still faces problems. Implementing classification-based and dynamic management for key noncommercial forests and establishing an eco-compensation mechanism with multiple funding sources in the market economy are the key measures needed to conquer these problems and improve the forest eco-compensation system and China's forestry development in sequence.

Being Right Isn't Always Enough: NFL Culture and Team Physicians' Conflict of Interest.

Science.gov (United States)

McKinney, Ross

2016-11-01

The job of being a sports team physician is difficult, regardless of the level, from high school to the National Football League. When a sports league receives the intensity of attention leveled at the NFL, though, a difficult occupation becomes even more challenging. Even for the NFL players themselves, players' best interests regarding health issues are often unclear. Football players are, as a lot, highly competitive individuals. They want to win, and they want to help the team win. It's a warrior culture, and respect is earned by playing hurt. Should the team physician respect a player's autonomy when this means allowing him to make choices that might lead to further personal harm, especially if the player's choices align with the preference of the coach and management? Or should the doctor set limits and balance the player's choices with a paternalistic set of constraints, perhaps in opposition to both the player's and the team's desires? Simplification of this web of conflicts of interest is the goal of the model proposed by Glenn Cohen, Holly Lynch, and Christopher Deubert. In my view, their proposal is very clever. As an idea, it meets the expectations its authors set, namely, to minimize the problem of conflict of interest in the delivery of health care services to NFL football players. The ethics of the proposal align well with certain moral goals, like treating the player's interests more fairly and treating the player's health as an end instead of as the means to an end. But will such a proposal ever make headway in the pressurized environment of the NFL? © 2016 The Hastings Center.

Bus-stop Based Real Time Passenger Information System - Case Study Maribor

Science.gov (United States)

Čelan, Marko; Klemenčič, Mitja; Mrgole, Anamarija L.; Lep, Marjan

2017-10-01

Real time passenger information system is one of the key element of promoting public transport. For the successful implementation of real time passenger information systems, various components should be considered, such as: passenger needs and requirements, stakeholder involvement, technological solution for tracking, data transfer, etc. This article carrying out designing and evaluation of real time passenger information (RTPI) in the city of Maribor. The design phase included development of methodology for selection of appropriate macro and micro location of the real-time panel, development of a real-time passenger algorithm, definition of a technical specification, financial issues and time frame. The evaluation shows that different people have different requirements; therefore, the system should be adaptable to be used by various types of people, according to the age, the purpose of journey, experience of using public transport, etc. The average difference between perceived waiting time for a bus is 35% higher than the actual waiting time and grow with the headway increase. Experiences from Maribor have shown that the reliability of real time passenger system (from technical point of view) must be close to 100%, otherwise the system may have negative impact on passengers and may discourage the use of public transport. Among considered events of arrivals during the test period, 92% of all prediction were accurate. The cost benefit analysis has focused only on potential benefits from reduced perceived users waiting time and foreseen costs of real time information system in Maribor for 10 years’ period. Analysis shows that the optimal number for implementing real time passenger information system at the bus stops in Maribor is set on 83 bus stops (approx. 20 %) with the highest number of passenger. If we consider all entries at the chosen bus stops, the total perceived waiting time on yearly level could be decreased by about 60,000 hours.

Assessing rear-end crash potential in urban locations based on vehicle-by-vehicle interactions, geometric characteristics and operational conditions.

Science.gov (United States)

Dimitriou, Loukas; Stylianou, Katerina; Abdel-Aty, Mohamed A

2018-03-01

Rear-end crashes are one of the most frequently occurring crash types, especially in urban networks. An understanding of the contributing factors and their significant association with rear-end crashes is of practical importance and will help in the development of effective countermeasures. The objective of this study is to assess rear-end crash potential at a microscopic level in an urban environment, by investigating vehicle-by-vehicle interactions. To do so, several traffic parameters at the individual vehicle level have been taken into consideration, for capturing car-following characteristics and vehicle interactions, and to investigate their effect on potential rear-end crashes. In this study rear-end crash potential was estimated based on stopping distance between two consecutive vehicles, and four rear-end crash potential cases were developed. The results indicated that 66.4% of the observations were estimated as rear-end crash potentials. It was also shown that rear-end crash potential was presented when traffic flow and speed standard deviation were higher. Also, locational characteristics such as lane of travel and location in the network were found to affect drivers' car following decisions and additionally, it was shown that speeds were lower and headways higher when Heavy Goods Vehicles lead. Finally, a model-based behavioral analysis based on Multinomial Logit regression was conducted to systematically identify the statistically significant variables in explaining rear-end risk potential. The modeling results highlighted the significance of the explanatory variables associated with rear-end crash potential, however it was shown that their effect varied among different model configurations. The outcome of the results can be of significant value for several purposes, such as real-time monitoring of risk potential, allocating enforcement units in urban networks and designing targeted proactive safety policies. Copyright © 2018 Elsevier Ltd. All rights

Driving context influences drivers' decision to engage in visual-manual phone tasks: Evidence from a naturalistic driving study.

Science.gov (United States)

Tivesten, Emma; Dozza, Marco

2015-06-01

Visual-manual (VM) phone tasks (i.e., texting, dialing, reading) are associated with an increased crash/near-crash risk. This study investigated how the driving context influences drivers' decisions to engage in VM phone tasks in naturalistic driving. Video-recordings of 1,432 car trips were viewed to identify VM phone tasks and passenger presence. Video, vehicle signals, and map data were used to classify driving context (i.e., curvature, other vehicles) before and during the VM phone tasks (N=374). Vehicle signals (i.e., speed, yaw rate, forward radar) were available for all driving. VM phone tasks were more likely to be initiated while standing still, and less likely while driving at high speeds, or when a passenger was present. Lead vehicle presence did not influence how likely it was that a VM phone task was initiated, but the drivers adjusted their task timing to situations when the lead vehicle was increasing speed, resulting in increasing time headway. The drivers adjusted task timing until after making sharp turns and lane change maneuvers. In contrast to previous driving simulator studies, there was no evidence of drivers reducing speed as a consequence of VM phone task engagement. The results show that experienced drivers use information about current and upcoming driving context to decide when to engage in VM phone tasks. However, drivers may fail to sufficiently increase safety margins to allow time to respond to possible unpredictable events (e.g., lead vehicle braking). Advanced driver assistance systems should facilitate and possibly boost drivers' self-regulating behavior. For instance, they might recognize when appropriate adaptive behavior is missing and advise or alert accordingly. The results from this study could also inspire training programs for novice drivers, or locally classify roads in terms of the risk associated with secondary task engagement while driving. Copyright © 2015. Published by Elsevier Ltd.

Impact of Rainfall on Multilane Roundabout Flowrate Contraction

Science.gov (United States)

PARKSHIR, Amir; BEN-EDIGBE, Johnnie

2017-08-01

In this study, roundabouts at two sites in the Malaysia were investigated under rainy and dry weather conditions. Two automatic traffic counters per roundabout arm as well as two rain gauge stations were used to collect data at each surveyed site. Nearly one million vehicles were investigated at four sites. Vehicle volume, speeds and headways for entry and circulating flows were collected continuously at each roundabout about arm for six weeks between November 2013 and January 2014. Empirical regression technique and gap-acceptance models were modified and used to analyze roundabout capacity. Good fits to the data were obtained; the results also fit models developed in other countries. It was assumed that entry capacity depends on the geometric characteristics of the roundabout, particularly the diameter of the outside circle of the intersection. It was also postulated that geometric characteristics determine the speed of vehicles around the central island and, therefore, have an impact on the gap-acceptance process and consequently the capacity. Only off-peak traffic data per light, moderate or heavy rainfall were analysed. Peak traffic data were not used because of the presence of peak traffic flow. Passenger car equivalent values being an instrument of conversion from traffic volume to flow were modified. Results show that, average entry capacity loss is about 22.6% under light rainfall, about 18.1% under moderate rainfall and about 5.6% under heavy rainfall. Significant entry capacity loss would result from rainfall irrespective of their intensity. It can be postulated that entry capacity loss under heavy rainfall is lowest because the advantage enjoyed by circulating flow would be greatly reduced with increased rainfall intensity. The paper concluded that rainfall has significant impact of flowrate contraction at roundabouts.

Toward Multi-scale Modeling and simulation of conduction in heterogeneous materials

Energy Technology Data Exchange (ETDEWEB)

Lechman, Jeremy B. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Battaile, Corbett Chandler. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Bolintineanu, Dan [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Cooper, Marcia A. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Erikson, William W. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Foiles, Stephen M. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Kay, Jeffrey J [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Phinney, Leslie M. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Piekos, Edward S. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Specht, Paul Elliott [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Wixom, Ryan R. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Yarrington, Cole [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

2015-01-01

This report summarizes a project in which the authors sought to develop and deploy: (i) experimental techniques to elucidate the complex, multiscale nature of thermal transport in particle-based materials; and (ii) modeling approaches to address current challenges in predicting performance variability of materials (e.g., identifying and characterizing physical- chemical processes and their couplings across multiple length and time scales, modeling information transfer between scales, and statically and dynamically resolving material structure and its evolution during manufacturing and device performance). Experimentally, several capabilities were successfully advanced. As discussed in Chapter 2 a flash diffusivity capability for measuring homogeneous thermal conductivity of pyrotechnic powders (and beyond) was advanced; leading to enhanced characterization of pyrotechnic materials and properties impacting component development. Chapter 4 describes success for the first time, although preliminary, in resolving thermal fields at speeds and spatial scales relevant to energetic components. Chapter 7 summarizes the first ever (as far as the authors know) application of TDTR to actual pyrotechnic materials. This is the first attempt to actually characterize these materials at the interfacial scale. On the modeling side, new capabilities in image processing of experimental microstructures and direct numerical simulation on complicated structures were advanced (see Chapters 3 and 5). In addition, modeling work described in Chapter 8 led to improved prediction of interface thermal conductance from first principles calculations. Toward the second point, for a model system of packed particles, significant headway was made in implementing numerical algorithms and collecting data to justify the approach in terms of highlighting the phenomena at play and pointing the way forward in developing and informing the kind of modeling approach originally envisioned (see Chapter 6). In

Design Principles in Polymer-Fullerene BHJ Solar Cells: PBDTTPD as a Case Study

KAUST Repository

Beaujuge, Pierre

2015-06-29

Among Organic Electronics, solution-processable π-conjugated polymers are proving particularly promising in bulk-heterojunction (BHJ) solar cells with fullerene acceptors such as PCBM.[1] In recent years, great headway has been made in the development of efficient polymer donors across the community, with published power conversion efficiencies (PCE) >8% in single cells and >10% in tandems. In most reports, these systems involve elaborate repeat unit and side chain patterns, and deviating from those patterns induces substantial drops in device PCE. While the range of polymer design parameters that impact BHJ solar cell performance remains a matter of some debate, our recent developments indicate that the combination of side-chain substituents appended to the main chain critically impacts polymer performance. For example, in poly(benzo[1,2-b:4,5-b’]dithiophene–thieno[3,4-c]pyrrole-4,6-dione) (PBDTTPD), side-chain substituents of various size and branching impart distinct molecular packing distances (i.e., π–π stacking and lamellar spacing), varying degrees of nanostructural order in thin films, and preferential backbone orientation relative to the device substrate.[2-5] While these structural variations seem to correlate with BHJ solar cell performance, with power conversion efficiencies ranging from 4% to 8.5%,[2,3] we believe that other contributing parameters – such as the local conformations between the polymer and the fullerene, and the domain distribution/composition across the BHJ (i.e., pure/mixed phases) – should also be taken into account.[6,7] Other discrete modifications of PBDTTPD’s molecular structure affect polymer performance in BHJ solar cells with PCBM, and our recent developments emphasize how systematic structure-property relationship studies impact the design of efficient polymer donors for BHJ solar cell applications.[8-10] It is important to further our understanding of these effects as we look to continue improving BHJ solar

Can Cape Town's unique biodiversity be saved? Balancing conservation imperatives and development needs

Directory of Open Access Journals (Sweden)

Patricia M. Holmes

2012-06-01

Full Text Available Cape Town is an urban hotspot within the Cape Floristic Region global biodiversity hotspot. This city of 2,460 km² encompasses four local centers of fynbos plant endemism, 19 national terrestrial vegetation types (six endemic to the city, wetland and coastal ecosystems, and 190 endemic plant species. Biodiversity in the lowlands is under threat of extinction as a result of habitat loss to agriculture, urban development, mining, and degradation by invasive alien plants. Cape Town's population is 3.7 million, increasing by an estimated 55,000 people/yr, which puts pressure on biodiversity remnants for development. South Africa is a signatory to international instruments to reduce biodiversity loss and has a good legislative and policy framework to conserve biodiversity, yet implementation actions are slow, with limited national and provincial support to conserve Cape Town's unique and irreplaceable biodiversity. The lack-of-action problem is two-fold: national government is slow to implement the policies developed to realize the international instruments it has signed, with conservation initiatives inadequately funded; and local governments are not yet recognized as important implementation partners. A further problem is created by conflicting policies such as the national housing policy that contributes to urban sprawl and loss of critical biodiversity areas. The City's Biodiversity Management Branch, with partners, is making some headway at implementation, but stronger political commitment is needed at all levels of government. Our objective is to improve the status and management of biodiversity in existing conservation areas through the statutory proclamation process and management effectiveness monitoring, respectively, and to secure priority areas of the BioNet, Cape Town's systematic biodiversity plan. The most important tools for the latter are incorporating the BioNet plan into City spatial plans; communication, education, and public

Refurbishment and replacement efforts to mitigate ageing at Tarapur Atomic Power Station - an overview

International Nuclear Information System (INIS)

Katiyar, S.C.; Thattey, V.; Das, P.K.

2006-01-01

Tarapur Atomic Power Station (TAPS) - a twin Boiling Water Reactor unit and India's first Atomic Power Station was commissioned in April 1969, and was declared commercial in November 1969. Since then the light water moderated, low enriched uranium BWR with its demonstrated reliability and favourable economics is playing a vital role as a reliable source of power for the states of Maharashtra and Gujarat. The Power Station played a key role as a technology demonstrator validating the nuclear energy as safe and environmentally benign and economically viable alternate source of power generation in India. Built in the late sixties with state-of-the-art safety features prevailing then, TAPS has further evolved to be a safe plant with renovation and refurbishment efforts. Ageing Management Programme is in place at TAPS. Identification of systems, structures and components (SSCs) important to safety and availability, assessment of ageing degradation of these SSCs and mitigation through repair, replacement and refurbishment based on the investigations have enhanced the plant safety and reliability. The station's operating experience and feedback from BWRs operating abroad have also given inputs to Ageing Management Programme. A good number of major equipment have been replaced to mitigate ageing. Primary system piping, process heat exchangers, feed water heaters, turbine extraction system piping, turbine blades, emergency condenser tube bundles, various pumps, station batteries, electrical cables, circuit breakers etc. are some of them. Obsolescence is another aspect of ageing of a plant. Replacement of obsolete equipment and components particularly in C and I is another area where much headway has been made. Replacement and refurbishment of equipment have been done after detailed study and analysis so that current standards are met. Retrofitting the indigenously developed and fabricated equipment in a compact plant like TAPS was a difficult task and required lot of

Passengers’ Perspective Toward Airport Service Quality (ASQ (Case Study at Soekarno-Hatta International Airport

Directory of Open Access Journals (Sweden)

Ridha Kurniawan

2017-01-01

Full Text Available Passenger satisfaction towards airport service quality is influenced by the level of service at the previous service quality. It causes the new facility is expected to exceed the previous service quality. Service quality improvement of people mover system in Grand Design of Soekarno Hatta International Airport (SHIA expected to support increasing airport service quality management. People mover existing conditions that occur on a free shuttle bus has caused some customer complaint. The purpose of this thesis is providing strategic support as complaint handling on people mover system to enhancing SHIA service quality. The discussion involves a passenger's perspectives, passengers’ satisfaction, and airport service quality to get a purpose of research. This thesis utilizes Fodness and Murray (2007 theory regarding the accurate scale to measure SHIA service quality by using Servqual method and Kano Model approach. Airport Service Quality (ASQ aims to give an airport more competitive in the relationship between business and operations. In this thesis offers support strategy in service quality attributes and considerations to assist airport management in improving airport service quality. This thesis finds the value gap between airport management and passengers’ perspectives that serve as accurate scale in each service attributes on people mover facility at SHIA that must be met to achieve satisfaction based on passengers’ perspectives. Also, this thesis finds several services attributes that must be met on people mover facility at SHIA as a basic service needs by passengers need. Airport management at SHIA should focus on the improved operating system of people mover system related to attributes punctuality, free of charge, information about the schedule, headway, and safety. This thesis presents the relationship between the value gap with service attributes that must be met by passengers’ perspectives, passengers’ satisfaction, and

AI's Philosophical Underpinnings: A Thinking Person's Walk through the Twists and Turns of Artificial Intelligence's Meandering Path

Science.gov (United States)

Colombano, Silvano; Norvig, Peter (Technical Monitor)

2000-01-01

Few human endeavors can be viewed both as extremely successful and unsuccessful at the same time. This is typically the case when goals have not been well defined or have been shifting in time. This has certainly been true of Artificial Intelligence (AI). The nature of intelligence has been the object of much thought and speculation throughout the history of philosophy. It is in the nature of philosophy that real headway is sometimes made only when appropriate tools become available. Similarly the computer, coupled with the ability to program (at least in principle) any function, appeared to be the tool that could tackle the notion of intelligence. To suit the tool, the problem of the nature of intelligence was soon sidestepped in favor of this notion: If a probing conversation with a computer could not be distinguished from a conversation with a human, then AI had been achieved. This notion became known as the Turing test, after the mathematician Alan Turing who proposed it in 1950. Conceptually rich and interesting, these early efforts gave rise to a large portion of the field's framework. Key to AI, rather than the 'number crunching' typical of computers until then, was viewed as the ability to manipulate symbols and make logical inferences. To facilitate these tasks, AI languages such as LISP and Prolog were invented and used widely in the field. One idea that emerged and enabled some success with real world problems was the notion that 'most intelligence' really resided in knowledge. A phrase attributed to Feigenbaum, one of the pioneers, was 'knowledge is the power.' With this premise, the problem is shifted from 'how do we solve problems' to 'how do we represent knowledge.' A good knowledge representation scheme could allow one to draw conclusions from given premises. Such schemes took forms such as rules,frames and scripts. It allowed the building of what became known as expert systems or knowledge based systems (KBS).

An Introduction to Thinking about Trustworthy Research into the Genetics of Intelligence.

Science.gov (United States)

Parens, Erik; Appelbaum, Paul S

2015-01-01

The advent of new technologies has rekindled some hopes that it will be possible to identify genetic variants that will help to explain why individuals are different with respect to complex traits. At least one leader in the development of "whole genome sequencing"-the Chinese company BGI-has been quite public about its commitment to using the technique to investigate the genetics of intelligence in general and high intelligence in particular. Because one needs large samples to detect the small effects associated with small genetic differences in the sequence of those base pairs, to make headway with the new sequencing technologies, one also needs to enlist much larger numbers of study participants than geneticists have enrolled before. In an effort to increase the size of a sample, one team of researchers approached the Center for Talented Youth at Johns Hopkins University. They wanted to gain access to records concerning participants in CTY's ongoing Study of Exceptional Talent, and they wanted to approach those individuals to see if they would be willing to share samples of their DNA. We agreed that CTY's dilemma about whether to give the researchers access to those records raised larger questions about the ethics of research into the genetics of intelligence, and we decided to hold a workshop at The Hastings Center that could examine those questions. Our purpose was to create what, borrowing from Sarah Richardson, we came to call a "transformative conversation" about research into the genetics of general cognitive ability-a conversation that would take a wide and long view and would involve a diverse group of stakeholders, including both people who have been highly critical of the research and people who engage in it. This collection of essays, which grew out of that workshop, is intended to provide an introduction to and exploration of this complex and important area. © 2015 The Hastings Center.

The Next Generation of Orthotopic Thyroid Cancer Models: Immunocompetent Orthotopic Mouse Models of BRAFV600E-Positive Papillary and Anaplastic Thyroid Carcinoma

Science.gov (United States)

Vanden Borre, Pierre; McFadden, David G.; Gunda, Viswanath; Sadow, Peter M.; Varmeh, Shohreh; Bernasconi, Maria; Jacks, Tyler

2014-01-01

Background: While the development of new treatments for aggressive thyroid cancer has advanced in the last 10 years, progress has trailed headways made with other malignancies. A lack of reliable authenticated human cell lines and reproducible animal models is one major roadblock to preclinical testing of novel therapeutics. Existing xenograft and orthotopic mouse models of aggressive thyroid cancer rely on the implantation of highly passaged human thyroid carcinoma lines in immunodeficient mice. Genetically engineered models of papillary and undifferentiated (anaplastic) thyroid carcinoma (PTC and ATC) are immunocompetent; however, slow and stochastic tumor development hinders high-throughput testing. Novel models of PTC and ATC in which tumors arise rapidly and synchronously in immunocompetent mice would facilitate the investigation of novel therapeutics and approaches. Methods: We characterized and utilized mouse cell lines derived from PTC and ATC tumors arising in genetically engineered mice with thyroid-specific expression of endogenous BrafV600E/WT and deletion of either Trp53 (p53) or Pten. These murine thyroid cancer cells were transduced with luciferase- and GFP-expressing lentivirus and implanted into the thyroid glands of immunocompetent syngeneic B6129SF1/J mice in which the growth characteristics were assessed. Results: Large locally aggressive thyroid tumors form within one week of implantation. Tumors recapitulate their histologic subtype, including well-differentiated PTC and ATC, and exhibit CD3+, CD8+, B220+, and CD163+ immune cell infiltration. Tumor progression can be followed in vivo using luciferase and ex vivo using GFP. Metastatic spread is not detected at early time points. Conclusions: We describe the development of the next generation of murine orthotopic thyroid cancer models. The implantation of genetically defined murine BRAF-mutated PTC and ATC cell lines into syngeneic mice results in rapid and synchronous tumor formation. This

Tadzhikistan-Russia: Geopolitical Relations at the Turn of the Century

Directory of Open Access Journals (Sweden)

Zafari Sherali Saidzoda

2015-01-01

Full Text Available In this article the writer analyses the development peculiarities of the Tajik-Russian geopolitical relations during the establishment of Tajikistan foreign policy up to the commencement of multi-vector «open doors» policy in 2003-2004. Since the establishment of peace and stability in Tajikistan beginning from the year of 2000 the socio-economic development issues have been set as prior actions. To boost the economy, attraction of foreign investments, creation of new jobs and improvement of life standard of population were the issues to address. Political leaders of Tajikistan had no right to waste time making no headway. The country inevitably faced the issue of diversification of interstate and foreign economic relations, including outside the CIS. The article highlights that the foreign «open door» policy declared at the turn of2002-2003 implied mandatory modernization of the Tajik-Russian cooperation through strengthening its economic and human dimensions, adjusting the strategic partnership and alliance between the two states to the new global political realities. As to the geopolitical and military-political priorities, which Tajikistan had firmly adhered throughout the entire 1990th since its Independence, they actually remained unchanged even after 2002. The author points out the long-term Russian presence in the form of a large scale military base and military infrastructure on the territory of Tajikistan. The Republic is one of the most consistent, active and disciplined members of the Collective Security Treaty Organization. During the first decade of the XXI century the political leaders of Tajikistan had been receiving offers from foreign non CIS countries with regard to deployment of military facilities on a fee basis on the territory of Tajikistan which were not even considered by the Government. Thus, the multi-vector foreign policy of «open doors» has been reflected in diversification of the international relations of

Grassland Aboveground Biomass in Inner Mongolia: Dynamics (2001-2016) and Driving force

Science.gov (United States)

Li, F.; Zeng, Y.; Chen, J.; Wu, B.

2017-12-01

Plant biomass is the most critical measure of carbon stored in an ecosystem, yet it remains imprecisely modeled for many terrestrial biomes. This lack of modeling capacity for biomass and its change through time and space has impeded scientists from making headway concerning issues in the geographic and social sciences. Satellite remote sensing techniques excel at detecting changes in the Earth's surface; however, accurate estimates of biomass for the heterogeneous biome landscapes based on remote sensing techniques are few and far between, which has led to many repetitive studies. Here, we argued that our ability to assess biomass in a heterogeneous landscape using satellite remote sensing techniques would be effectively enhanced through a stratification of landscapes, i.e homogenizing landscapes. Specifically, above-ground biomass (AGB) for an extended heterogeneous grassland biome over the entirety of Inner Mongolia during the past 16 years (2001-2016) was explored using remote sensing time series data from the Moderate Resolution Imaging Spectroradiometer (MODIS). Massive and extensive in-situ measurement AGB data and pure vegetation index (PVI) models, developed from normal remote sensing vegetation indices such as the normalized difference vegetation index (NDVI) and the enhanced vegetation index (EVI), were highlighted in the accomplishment of this study. Taking into full consideration the landscape heterogeneity for the grassland biome over Inner Mongolia, we achieved a series of AGB models with high R2 (>0.85) and low RMSE ( 20.85 g/m2). The total average amount of fresh AGB for the entirety of Inner Mongolia grasslands over the past 16 years was estimated as 87 Tg with an inter-annual standard deviation of 9 Tg. Overall, the grassland AGB for Inner Mongolia increased sporadically. We found that the dynamics of AGB in the grassland biome of Inner Mongolia were substantially dominated by variation in precipitation despite the accommodation of a huge

Upper-Ocean Heat Balance Processes and the Walker Circulation in CMIP5 Model Projections

Science.gov (United States)

Robertson, F. R.; Roberts, J. B.; Funk, C.; Lyon, B.; Ricciardulli, L.

2012-01-01

Considerable uncertainty remains as to the importance of mechanisms governing decadal and longer variability of the Walker Circulation, its connection to the tropical climate system, and prospects for tropical climate change in the face of anthropogenic forcing. Most contemporary climate models suggest that in response to elevated CO2 and a warmer but more stratified atmosphere, the required upward mass flux in tropical convection will diminish along with the Walker component of the tropical mean circulation as well. Alternatively, there is also evidence to suggest that the shoaling and increased vertical stratification of the thermocline in the eastern Pacific will enable a muted SST increase there-- preserving or even enhancing some of the dynamical forcing for the Walker cell flow. Over the past decade there have been observational indications of an acceleration in near-surface easterlies, a strengthened Pacific zonal SST gradient, and globally-teleconnected dislocations in precipitation. But is this evidence in support of an ocean dynamical thermostat process posited to accompany anthropogenic forcing, or just residual decadal fluctuations associated with variations in warm and cold ENSO events and other stochastic forcing? From a modeling perspective we try to make headway on this question by examining zonal variations in surface energy fluxes and dynamics governing tropical upper ocean heat content evolution in the WCRP CMIP5 model projections. There is some diversity among model simulations; for example, the CCSM4 indicates net ocean warming over the IndoPacific region while the CSIRO model concentrates separate warming responses over the central Pacific and Indian Ocean regions. The models, as with observations, demonstrate strong local coupling between variations in column water vapor, downward surface longwave radiation and SST; but the spatial patterns of changes in the sign of this relationship differ among models and, for models as a whole, with

The consequences of an increase in heavy goods vehicles for passenger car drivers' mental workload and behaviour: a simulator study.

Science.gov (United States)

de Waard, Dick; Kruizinga, Anje; Brookhuis, Karel A

2008-03-01

The effects of an increase in Heavy Goods Vehicles (HGVs) on merging behaviour and on mental workload of motorists during filtering in and out of traffic were studied. Participants drove in a driving simulator in a total of 12 conditions; twice in each of two weather conditions and in three traffic conditions. The weather conditions were clear weather and foggy weather. The traffic conditions were without HGVs (i.e. only private cars), the current mix of HGVs and private cars, and a condition with a 70% increase of HGVs leading to an HGV column in the slow lane. The focus of the study was on assessing effects on behaviour and mental workload during filtering into traffic, and during exiting from the motorway. During the experiment driving performance was registered, behaviour was observed, self reports were collected, and the participant's heart rate was recorded. The results showed that directly after filtering into traffic the variation in driving speed increased and the minimum time headway decreased with an increase in the proportion of HGVs. Joining motorway traffic was considered to involve greater effort and risk in the condition with a column of HGVs. The effects of the conditions on heart rate are less clear, although the moment when the participants joined the traffic is clearly visible. The effects of weather conditions were limited, drivers adapting their driving behaviour in adverse weather by reducing speed. To exit the motorway is not a difficult manoeuvre. For that reason the lane change from the left hand to the right hand lane that preceded the exit was analysed. Although increased mental effort was reported and the lane change was visible in the heart rate record, no critical changes as a result of increase in proportion of HGVs were found for this manoeuvre. However, in the condition with a column of HGVs, the exit that had to be taken was most frequently missed as HGVs obstructed the view of the exit signs. It is concluded that an increase in

INFORMATION SYSTEM SECURITY (CYBER SECURITY

Directory of Open Access Journals (Sweden)

Muhammad Siddique Ansari

2016-03-01

Full Text Available Abstract - Business Organizations and Government unequivocally relies on upon data to deal with their business operations. The most unfavorable impact on association is disappointment of friendship, goodness, trustworthiness, legitimacy and probability of data and administrations. There is an approach to ensure data and to deal with the IT framework's Security inside association. Each time the new innovation is made, it presents some new difficulties for the insurance of information and data. To secure the information and data in association is imperative on the grounds that association nowadays inside and remotely joined with systems of IT frameworks. IT structures are inclined to dissatisfaction and security infringement because of slips and vulnerabilities. These slips and vulnerabilities can be brought on by different variables, for example, quickly creating headway, human slip, poor key particulars, poor movement schedules or censuring the threat. Likewise, framework changes, new deserts and new strikes are a huge piece of the time displayed, which helpers augmented vulnerabilities, disappointments and security infringement all through the IT structure life cycle. The business went to the confirmation that it is essentially difficult to ensure a slip free, risk free and secure IT structure in perspective of the disfigurement of the disavowing security parts, human pass or oversight, and part or supplies frustration. Totally secure IT frameworks don't exist; just those in which the holders may have changing degrees of certainty that security needs of a framework are fulfilled do. The key viewpoints identified with security of data outlining are examined in this paper. From the start, the paper recommends pertinent legitimate structure and their duties including open association obligation, and afterward it returns to present and future time, system limits, structure security in business division. At long last, two key inadequacy markers

A rear-end collision risk assessment model based on drivers' collision avoidance process under influences of cell phone use and gender-A driving simulator based study.

Science.gov (United States)

Li, Xiaomeng; Yan, Xuedong; Wu, Jiawei; Radwan, Essam; Zhang, Yuting

2016-12-01

Driver's collision avoidance performance has a direct link to the collision risk and crash severity. Previous studies demonstrated that the distracted driving, such as using a cell phone while driving, disrupted the driver's performance on road. This study aimed to investigate the manner and extent to which cell phone use and driver's gender affected driving performance and collision risk in a rear-end collision avoidance process. Forty-two licensed drivers completed the driving simulation experiment in three phone use conditions: no phone use, hands-free, and hand-held, in which the drivers drove in a car-following situation with potential rear-end collision risks caused by the leading vehicle's sudden deceleration. Based on the experiment data, a rear-end collision risk assessment model was developed to assess the influence of cell phone use and driver's gender. The cell phone use and driver's gender were found to be significant factors that affected the braking performances in the rear-end collision avoidance process, including the brake reaction time, the deceleration adjusting time and the maximum deceleration rate. The minimum headway distance between the leading vehicle and the simulator during the rear-end collision avoidance process was the final output variable, which could be used to measure the rear-end collision risk and judge whether a collision occurred. The results showed that although cell phone use drivers took some compensatory behaviors in the collision avoidance process to reduce the mental workload, the collision risk in cell phone use conditions was still higher than that without the phone use. More importantly, the results proved that the hands-free condition did not eliminate the safety problem associated with distracted driving because it impaired the driving performance in the same way as much as the use of hand-held phones. In addition, the gender effect indicated that although female drivers had longer reaction time than male drivers in

Existing ingestion guidance: Problems and recommendations

Energy Technology Data Exchange (ETDEWEB)

Mooney, Robert R; Ziegler, Gordon L; Peterson, Donald S [Environmental Radiation Section, Division of Radiation Protection, WA (United States)

1989-09-01

Washington State has been developing plans and procedures for responding to nuclear accidents since the early 1970s. A key part of this process has been formulating a method for calculating ingestion pathway concentration guides (CGs). Such a method must be both technically sound and easy to use. This process has been slow and frustrating. However, much technical headway has been made in recent years, and hopefully the experience of the State of Washington will provide useful insight to problems with the existing guidance. Several recommendations are offered on ways to deal with these problems. In January 1986, the state held an ingestion pathway exercise which required the determination of allowed concentrations of isotopes for various foods, based upon reactor source term and field data. Objectives of the exercise were not met because of the complexity of the necessary calculations. A major problem was that the allowed concentrations had to be computed for each isotope and each food group, given assumptions on the average diet. To solve problems identified during that exercise, Washington developed, by March 1986, partitioned CGs. These CGs apportioned doses from each food group for an assumed mix of radionuclides expected to result from a reactor accident. This effort was therefore in place just in time for actual use during the Chernobyl fallout episode in May 1986. This technique was refined and described in a later report and presented at the 1987 annual meeting of the Health Physics Society. Realizing the technical weaknesses which still existed and a need to simplify the numbers for decision makers, Washington State has been developing computer methods to quickly calculate, from an accident specific relative mix of isotopes, CGs which allow a single radionuclide concentration for all food groups. This latest approach allows constant CGs for different periods of time following the accident, instead of peak CGs, which are good only for a short time after the

UNEARTHING THE PURPORTS OF TRUST IN AUTHORITIES AND POWER OF AUTHORITIES IN THE LATIN AMERICAN TAX CLIMATE

Directory of Open Access Journals (Sweden)

LARISSA BǍTRÂNCEA

2014-06-01

decision-making on comprehensive valuations of trust and power may prove cost-effective for any authority concerned with enacting the appropriate weighting of tax incentives and enforcement strategies in order to enhance compliance; it may urge taxpayers to match the actions of an equitable authority and cooperate; it may serve investors as a guide to determine the efficiency, credibility and stability of Latin American fiscal systems; it may assist financing international organizations to detect the possible risks and vulnerabilities of the relationship between authorities and taxpayers and evaluate the headway/regress registered by a particular country within this tax climate. In terms of trust, various countries in the region have implemented solid strategies to sustain competitiveness, infrastructure, innovation or health. In terms of power, several tax authorities are deemed as rather weak in mitigating noncompliance. Nevertheless, massive investments in infrastructure prove commitment in nixing evasion.

Existing ingestion guidance: Problems and recommendations

International Nuclear Information System (INIS)

Mooney, Robert R.; Ziegler, Gordon L.; Peterson, Donald S.

1989-01-01

Washington State has been developing plans and procedures for responding to nuclear accidents since the early 1970s. A key part of this process has been formulating a method for calculating ingestion pathway concentration guides (CGs). Such a method must be both technically sound and easy to use. This process has been slow and frustrating. However, much technical headway has been made in recent years, and hopefully the experience of the State of Washington will provide useful insight to problems with the existing guidance. Several recommendations are offered on ways to deal with these problems. In January 1986, the state held an ingestion pathway exercise which required the determination of allowed concentrations of isotopes for various foods, based upon reactor source term and field data. Objectives of the exercise were not met because of the complexity of the necessary calculations. A major problem was that the allowed concentrations had to be computed for each isotope and each food group, given assumptions on the average diet. To solve problems identified during that exercise, Washington developed, by March 1986, partitioned CGs. These CGs apportioned doses from each food group for an assumed mix of radionuclides expected to result from a reactor accident. This effort was therefore in place just in time for actual use during the Chernobyl fallout episode in May 1986. This technique was refined and described in a later report and presented at the 1987 annual meeting of the Health Physics Society. Realizing the technical weaknesses which still existed and a need to simplify the numbers for decision makers, Washington State has been developing computer methods to quickly calculate, from an accident specific relative mix of isotopes, CGs which allow a single radionuclide concentration for all food groups. This latest approach allows constant CGs for different periods of time following the accident, instead of peak CGs, which are good only for a short time after the

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

Science.gov (United States)

Li, Qing; Qiao, Fengxiang; Yu, Lei

2016-05-01

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

Pasarela metálica excéntrica suspendida y apoyada en un arco metálico en Orense, España

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Besiga Díaz-Blanco, Julio

2007-12-01

Full Text Available The article explains the design and project of a steel footbridge, suspended and supported by an eccentric arc, situated in Orense. The footbridge, known as “Bellour”, has a main span of 20 meters, with a leaned steel eccentric arc that supports the deck. The deck was designed with a uniform slope of 8%, due the difference of level between each end. It is suspended from the arc in the Orense side and supported in the other boarder, because of the headway limitations. The deck is 2,80 meters wide. The cross section is composed of a steel eccentric tube with steel cantilever beams, of variable depth, and is joined at the other edge to a small steel tube. The pedestrian zone is narrower than the board, leaving individual empty spaces at both sides, and is constituted by a structural concrete slab of 7 centimeters thick and 2 meters wide, linked to the deck top sheet, with a steel profiles. The board was designed with a structural skeleton, spine shaped, suspended or supported from the arc, and it´s joined to the skin, a rough concrete surface that avoids frost and slides due to the rain.En este artículo se expone el diseño de una pasarela metálica excéntrica suspendida y apoyada en un arco metálico situada en la ciudad de Orense. La pasarela, conocida por «Bellour», tiene un único vano de 20 metros de luz, soportado excéntricamente por un arco metálico inclinado. Las cotas de inicio y fin de la pasarela obligaron a diseñar un tablero inclinado que está suspendido del arco en el lado Orense y apoyado en el otro extremo al permitirlo el gálibo de la carretera. La sección transversal del tablero está formada por un tubo excéntrico del que parten unas ménsulas metálicas de canto variable, unidas en su otro extremo por otro tubo más pequeño. El pavimento de la pasarela, que es más estrecho que el propio tablero, dejando sendos espacios vacíos a ambos lados, está formado por una losa de hormigón armado conectada a

Longitudinal control behaviour: Analysis and modelling based on experimental surveys in Italy and the UK.

Science.gov (United States)

Pariota, Luigi; Bifulco, Gennaro Nicola; Galante, Francesco; Montella, Alfonso; Brackstone, Mark

2016-04-01

because of the huge number of rear-end crashes. The increased availability of lower-cost information and communication technologies (ICTs) has enhanced the possibility of collecting copious and reliable car-following individual vehicle data. In this work, data collected from three different experiments, two carried out in Italy and one in the UK, are analysed and compared. The experiments involved 146 drivers (105 Italian drivers and 41 UK drivers). Data were collected by two instrumented vehicles. Our analysis focused on inter-vehicular spacing in equilibrium car-following conditions. We observed that (i) the adopted equilibrium spacing can be fitted using lognormal distributions, (ii) the adopted equilibrium spacing increases with speed, and (iii) the dispersion between drivers increases with speed. In addition, according to different headway thresholds (up to 1 second) a significant number of potentially dangerous behaviours is observed. Three different car-following paradigms are also applied to each of the experiments, and modelling parameters are calibrated and compared to obtain indirect confirmation about the observed similarities and differences in driving behaviour. Copyright © 2016 Elsevier Ltd. All rights reserved.

Staffing remote rural areas in middle- and low-income countries: A literature review of attraction and retention

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Dieleman Marjolein

2008-01-01

-income countries. About 600 papers were initially assessed and 55 eventually included in the review. Results The authors argue that, although factors are multi-facetted and complex, strategies are usually not comprehensive and often limited to addressing a single or limited number of factors. They suggest that because of the complex interaction of factors impacting on attraction and retention, there is a strong argument to be made for bundles of interventions which include attention to living environments, working conditions and environments and development opportunities. They further explore the organisational location of decision-making related to retention issues and suggest that because promising strategies often lie beyond the scope of human resource directorates or ministries of health, planning and decision-making to improve retention requires multi-sectoral collaboration within and beyond government. The paper provides a simple framework for bringing the key decision-makers together to identify factors and develop multi-facetted comprehensive strategies. Conclusion There are no set answers to the problem of attraction and retention. It is only through learning about what works in terms of fit between problem analysis and strategy and effective navigation through the politics of implementation that any headway will be made against the almost universal challenge of staffing health service in remote rural areas.

Different Categories of Astronomical Heritage: Issues and Challenges

Science.gov (United States)

Ruggles, Clive

2012-09-01

different forms of astronomical heritage, including its intangible aspects, that will help in the development of more integrated approaches to identification and cataloguing, protection and preservation; and 3. to increase global awareness of regional, national and local initiatives relating to astronomical heritage in all its forms. In pursuance of these aims, the meeting also recommended that the AWHWG, working in collaboration with the WGs on Astronomical Instruments and Archives, and other bodies as appropriate, should develop the following additional projects: 1. to establish guidelines to help in the identification and safeguarding of tangible and intangible astronomical heritage in all its forms; 2. to gather examples of existing best practice, and to make these available as case studies on their website; and 3. to develop the website of the Astronomy and World Heritage Initiative (AWHI) as a portal to existing on-line catalogues and thesauri. It also recommended that the WGs should work together to: 1. formulate recommendations about the ways in which links and common approaches should be developed in the future; and 2. organise a meeting of international experts in the historical and heritage aspects of astronomical structures, instruments, and archives, focussed specifically upon the task of developing more integrated approaches to identification and cataloguing, protection and preservation. This joint session will attempt to make headway on as many as possible of these issues. In this opening talk I will attempt to lay out some of the main challenges that we face, and outline what we hope to achieve in this session.

IN MY OPINION: What about person-sized physics?

Science.gov (United States)

Cornwall, Malcolm

1999-03-01

Why are the `popular science' shelves of our bookshops groaning under the weight of the numerous books on cosmology, the quantum world, the fundamental particle zoo and similar topics both mysterious and esoteric? The answer is obvious, of course - because there's a market out there. A sizeable proportion of the avid readers are no doubt bright young people eager to read about the wonders of science, or in this case physics, and be awed (overawed?) by the strange behaviour of matter and energy on scales unimaginably larger or smaller than ourselves. Good thing too, you might say. I agree - at least to the extent that this particular readership is excited and enthused by these popular tracts to study physics at A-level and perhaps beyond. Maybe not so good though, if the result is that some youngsters are turned off physics because it comes over as `OK for the bright ones but too difficult for me'. Cosmological and high energy physics is very difficult, and it's not just a matter of the mathematical skills that one needs to make any serious headway. The concepts involved are, to say the least, strange and counter-intuitive. This is great for triggering scientific curiosity and the excitement of physics, but how typical are they of the problems and challenges faced by the large majority of professional physicists, in industry, government research labs or, indeed, in academia? And how characteristic of the flavours of physics that the average A-level student or undergraduate will encounter? Recent correspondence in Physics World indicates that our undergraduate physics programmes are on the whole disappointingly bland compared with the expectations of graduates seduced, perhaps, by glimpses of quarks, superstrings and black holes. My argument is not that we shouldn't sell physics in this way, but that we could try to provide a more balanced sample of what physics is really about. Above all, we need to sell the idea - to the public at large as well as the potential

Towards reducing traffic congestion using cooperative adaptive cruise control on a freeway with a ramp

Directory of Open Access Journals (Sweden)

Georges Arnaout

2011-12-01

experiments and/or simulations provide a controlled setting, well suited for preliminary testing and calibrating of the input variables. However, laboratory testing is by no means sufficient for the entire methodology validation. It must be complemented by fundamental field testing. As far as the simulation model limitations, accidents, weather conditions, and obstacles in the roads were not taken into consideration. Failures in the operation of the sensors and communication of CACC design equipment were also not considered. Additionally, the special HOV lanes were limited to manual vehicles and CACC vehicles. Emergency vehicles, buses, motorcycles, and other type of vehicles were not considered in this dissertation. Finally, it is worthy to note that the human factor is far more sophisticated, hard to predict, and flexible to be exactly modeled in a traffic simulation model perfectly. Some human behavior could occur in real life that the simulation model proposed would fail to model.Practical implications: A high percentage of CACC market penetration is not occurring in the near future. Thus, reaching a high penetration will always be a challenge for this type of research. The public accessibility for such a technology will always be a major practical challenge. With such a small headway safety gap, even if the technology was practically proven to be efficient and safe, having the public to accept it and feel comfortable in using it will always be a challenge facing the success of the CACC technology.Originality/value: The literature on the impact of CACC on traffic dynamics is limited. In addition, no previous work has proposed an open-source microscopic traffic simulator where different CACC algorithms could be easily used and tested. We believe that the proposed model is more realistic than other traffic models, and is one of the very first models to model the behavior CACC vehicles on freeways.

混有协同自适应巡航控制车辆的异质交通流稳定性解析与基本图模型%Stability analysis and fundamental diagram of heterogeneous traffic flow mixed with cooperative adaptive cruise control vehicles

Institute of Scientific and Technical Information of China (English)

秦严严; 王昊; 王炜; 万千

2017-01-01

and CACC market penetration rates, if manual driven vehicles are stable. Otherwise, the instabil-ity of traditional traffic flow is improved gradually with the increase of the CACC market penetration rate. Additionally, the stability will become better when equilibrium velocity is away from the velocity range of 9.6–18.6 m/s. 2) Because CACC vehicles can travel at free-flow speed in a relatively small headway, CACC vehicles can improve the capacity of heterogeneous traffic flow. 3) The results of sensitivity analysis indicate that with the increase of the CACC desired time gap, the stable region of heterogeneous traffic flow increases. However, the capacity of the fundamental diagram drops. Therefore, the value of the desired time gap should be determined with considering the effects of the two aspects on the heterogeneous traffic flow. It is noted that the CACC model used in this paper is based on the current state-of-the-art real CACC vehicle experiments. In the future, more experimental observations will yield new CACC models. However, the framework presented in this paper can still be used for the analytical investigation of string stability of the heterogeneous traffic flow at that time.%针对传统车辆和协同自适应巡航控制(cooperative adaptive cruise control,CACC)车辆构成的异质交通流,研究其稳定性与基本图模型.应用实车测试验证的CACC模型和智能驾驶员模型(intelligent driver model)分别作为CACC车辆和传统车辆的跟驰模型,建立异质流稳定性解析框架,研究不同平衡态速度、不同CACC车辆比例时的异质流稳定性.推导异质流基本图模型,并进行数值仿真实验.研究结果表明,在传统车辆稳定的速度范围,异质流处于稳定状态.在传统车辆不稳定的速度范围,CACC车辆比例增加以及平衡态速度远离9.6—18.6 m

Experimental Measurement of the Flow Field of Heavy Trucks

Energy Technology Data Exchange (ETDEWEB)

Fred Browand; Charles Radovich

2005-05-31

trucks in a tandem configuration. In December 2003, such fuel consumption tests were performed at the same Crows Landing testsite. In the tests, two identical trucks are operated at headways in the range 3-10 meters. The trucks are steered by hand, but longitudinal control is provided by a closed-loop control system. Laser ranging measures truck-to-truck distance, and the control system maintains a truck separation to within about {+-} 3 centimeters. From these tests it is concluded that both trucks save fuel by close-following, that the fuel saving increases with decreasing spacing, and that the trail truck saves more fuel. An average value of fuel saving for each of the two trucks at spacings of 6-10 meters can be taken to be 3.0 liters/100 km.

Experimental studies on cold fusion and hydrogen-metal

International Nuclear Information System (INIS)

Locou, P.

2007-01-01

The cold fusion is a nuclear fusion realized in pervading conditions of temperature and pressure. My own process is parallel to that of the team of the University of Los Angeles, but shaped in 1996 within my personal and private Laboratory: A small cylinder in which we replace the air by some deuterium to the gas state in - 33 d egree (the deuterium is some hydrogen with a neutron, which we find in quantity in the sea water). We introduce a crystal there, extremely rare - the property of which is to emit continuously one thousand times dose of successful energy and it during several years without outside pyro, natural excitement - electric - that is it creates an electric field in the slightest change in temperature. We carry then the whole in + 7 d egree, what generates in some seconds a 200 000 volt electric field, an intense enough field to separate the pits of the deuterium of their electrons and to admit them to collide with those of the crystal. There is a fusion of protons between them (positive particles of the pit (core)) and a emission of neutrons, which do not merge. It is this emission which serves for measuring the quantity of energy produced by the fusion (merger). We so managed to produce some energy in unlimited quantity, allowing us to feed our installation with electric current in total autarky, and to reduce so our costs of functioning to divers domains. This crystal is exceptional in its applications and to give it the name would return has to break our current headway: the thorough problem, in this current period of takeover by the financial bodies of the possible patents, brought to us to the biggest caution as regards our results. And, as we look for no outside financing, we do not need to submit ourselves to the requirements lauded by the scientific Community, only our results are strictly estimated. For example we can make estimate our bars or patches of Hydrogen - Metal: a simple spectroscopy in YEW will give as result, only, the element H