WorldWideScience

Sample records for travel time savings

  1. Value of travel time savings

    DEFF Research Database (Denmark)

    Le Masurier, P.; Polak, J.; Pawlak, Janet

    2015-01-01

    A team of specialist market researchers and Value of Time experts comprising members from SYSTRA, Imperial College London and the Technical University of Denmark has conducted a formal audit and peer review of research undertaken by Arup/ITS Leeds/Accent to derive Value of Travel Time Savings...... Preference (RP) models that were used to derive final Values of Travel Time (VTT). This report contains the findings of our audit and peer review of the procedures adopted by the research team during data collection of the three surveys (SP, RP and Employers Surveys); a peer review of the reported approach...

  2. Principles of valuing business travel time savings

    OpenAIRE

    Fowkes, A.S.

    2001-01-01

    OVERVIEW\\ud \\ud There are two approaches to valuing travel time savings to business people. The first is that which has formed the basis of UK policy for about 30 years, and which is set out in Section 2. This takes the value of travel time savings on employer’s business as equal to the gross wage rate plus an allowance for other costs that the employer saves. These might include such things as desk space, computer, tools, uniform, protective clothing, travel expenses. These were investigated...

  3. The value of business travel time savings

    OpenAIRE

    Fowkes, A.S.; Marks, P.; Nash, C.A.

    1986-01-01

    The value of time savings for business travellers forms a sizeable part of the benefits from trunk road, rail and air transport improvement schemes. It is therefore important to possess appropiate values to place on business travel time savings for evaluation purposes. The normal approach in practice is to adopt the wage rate of the workers in question plus an increment for overheads and non-wage payments. \\ud \\ud In this paper criticisms of this approach are discssed and the implications of ...

  4. Swiss values of travel time savings

    OpenAIRE

    König, Arnd

    2004-01-01

    This study was conducted by the Institute of Transport Planning and Systems (IVT), ETH Zurich and Rapp Trans AG, Zurich on behalf of the Swiss Association of Transport Engineers. It implements the recommendation of the scoping study on Swiss value of travel time savings (VTTS) (Abay und Axhausen, 2000) by estimating VTTS for private motorised and public travel by trip purpose on the basis of new stated-choice (SC) surveys. The survey participants were recruited as part of the continuous passe...

  5. Valuation of travel time savings for intercity travel: The Madrid-Barcelona corridor

    DEFF Research Database (Denmark)

    Roman, Concepcion; Carlos Martin, Juan; Espino, Raquel

    2014-01-01

    We derive values of travel time savings (VOT) for the Madrid-Barcelona corridor, linking the two largest cities in Spain, based on the estimation of discrete choice models among the main public transport services in the corridor: air transport, high speed rail (HSR) and bus. The new HSR alternative...... to provide useful information to quantify users' benefits during the lifespan of a given project. We found, as expected, that HSR and air transport users exhibit substantially higher values for saving travel time than bus travellers. Also as expected, savings of waiting time are more valued than savings...

  6. Valuation of Travel Time Savings in Viewpoint of WTA

    Science.gov (United States)

    Shao, Chang-qiao; Liu, Yang; Liu, Xiao-ming

    2014-01-01

    In order to investigate the issues in measurement of value of travel time savings (VTTS), the willingness-to-accept (WTA) for the private car owner is studied by using surveyed data. It is convincing that trip purpose, trip length, time savings, cost savings, income, and allowance from employee have effects on the WTA. Moreover, influences of these variables are not the same for different trip purposes. For commuting trips, effects of income and allowance from employee are significant while time savings and cost savings are dominated for leisure and shopping trips. It is also found that WTA is much higher than expected which implies that there are a group of drivers who are not prone to switching to other trip modes other than passenger car. PMID:25530751

  7. Valuation of travel time savings in viewpoint of WTA.

    Science.gov (United States)

    Shao, Chang-Qiao; Liu, Yang; Liu, Xiao-Ming

    2014-01-01

    In order to investigate the issues in measurement of value of travel time savings (VTTS), the willingness-to-accept (WTA) for the private car owner is studied by using surveyed data. It is convincing that trip purpose, trip length, time savings, cost savings, income, and allowance from employee have effects on the WTA. Moreover, influences of these variables are not the same for different trip purposes. For commuting trips, effects of income and allowance from employee are significant while time savings and cost savings are dominated for leisure and shopping trips. It is also found that WTA is much higher than expected which implies that there are a group of drivers who are not prone to switching to other trip modes other than passenger car.

  8. Issues in the valuation of travel time savings

    DEFF Research Database (Denmark)

    Gissel, Stine

    1998-01-01

    The subject of the paper is the valuation of travel time savings (emanating from investment in transport infrastructure). In the first part of the paper the question is approached within a microeconomic framework. It is discussed if and how the theory can give indications on the relative value...... of travel time elements and on the extrapolation of time values into the future. In the second part of the paper the same questions are investigated on the basis of the results of several empirical studies....

  9. Investigating the distribution of the value of travel time savings

    DEFF Research Database (Denmark)

    Fosgerau, Mogens

    2006-01-01

    . Increasing the implicit price of time leads to an increased share of respondents who decline to pay to save time. But a significant proportion of respondents, 13%, remain willing to pay to save time at the highest price of time in the design. This means that the right tail of the VTTS distribution...... is not observed and hence the mean VTTS cannot be evaluated without additional assumptions. When socio-economic and situational variables are introduced into a semiparametric model it becomes possible to accept that the whole VTTS distribution is observed. Sixteen candidates for parametric VTTS distributions...... are investigated. Some distributions are simply not able to fit to the empirical distribution while others have very long tails. The mean VTTS is shown to be extremely dependent on the choice of parametric distribution. Requiring that the parametric distribution should be accepted against the nonparametric...

  10. Improving value of travel time savings estimation for more effective transportation project evaluation.

    Science.gov (United States)

    2012-12-01

    Estimates of value of time (VOT) and value of travel time savings (VTTS) are critical elements in benefitcost : analyses of transportation projects and in developing congestion pricing policies. In addition, : differences in VTTS among various modes ...

  11. An international meta-analysis of values of travel time savings.

    Science.gov (United States)

    Shires, J D; de Jong, G C

    2009-11-01

    Values of travel time savings are often used in cost-benefit analysis of transport projects and policies, and also to compute generalised travel costs. There has been considerable debate as to whether different research methods (e.g. stated versus revealed preference) will lead to different values of travel time savings, and which segmentations (e.g. by income or mode) are most important to capture the heterogeneity in these values. In addition there are many countries where no specific valuation studies have been done. In this paper new equations are estimated on the outcomes of value of travel time savings studies from various countries. In the data set, several countries appear more than once, which is taken into account by estimating random effects panel models. The meta-analysis sheds some new light on the variation of the value of travel time savings by income, country, travel purpose, mode, distance and by survey method. Furthermore, the resulting meta-models are applied to produce new values of travel time savings for business travel, commuting and for other purposes in passenger transport, for 25 European Union Member states. Similar methods could be used to statistically analyse studies carried out on other non-monetary effects, both for transport and non-transport projects, and for inclusion in cost-benefit analysis.

  12. Estimating the Value of Life, Injury, and Travel Time Saved Using a Stated Preference Framework.

    Science.gov (United States)

    Niroomand, Naghmeh; Jenkins, Glenn P

    2016-06-01

    The incidence of fatality over the period 2010-2014 from automobile accidents in North Cyprus is 2.75 times greater than the average for the EU. With the prospect of North Cyprus entering the EU, many investments will need to be undertaken to improve road safety in order to reach EU benchmarks. The objective of this study is to provide local estimates of the value of a statistical life and injury along with the value of time savings. These are among the parameter values needed for the evaluation of the change in the expected incidence of automotive accidents and time savings brought about by such projects. In this study we conducted a stated choice experiment to identify the preferences and tradeoffs of automobile drivers in North Cyprus for improved travel times, travel costs, and safety. The choice of route was examined using mixed logit models to obtain the marginal utilities associated with each attribute of the routes that consumers choose. These estimates were used to assess the individuals' willingness to pay (WTP) to avoid fatalities and injuries and to save travel time. We then used the results to obtain community-wide estimates of the value of a statistical life (VSL) saved, the value of injury (VI) prevented, and the value per hour of travel time saved. The estimates for the VSL range from €315,293 to €1,117,856 and the estimates of VI from € 5,603 to € 28,186. These values are consistent, after adjusting for differences in incomes, with the median results of similar studies done for EU countries. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Impact of a University-Based Outpatient Telemedicine Program on Time Savings, Travel Costs, and Environmental Pollutants.

    Science.gov (United States)

    Dullet, Navjit W; Geraghty, Estella M; Kaufman, Taylor; Kissee, Jamie L; King, Jesse; Dharmar, Madan; Smith, Anthony C; Marcin, James P

    2017-04-01

    The objective of this study was to estimate travel-related and environmental savings resulting from the use of telemedicine for outpatient specialty consultations with a university telemedicine program. The study was designed to retrospectively analyze the telemedicine consultation database at the University of California Davis Health System (UCDHS) between July 1996 and December 2013. Travel distances and travel times were calculated between the patient home, the telemedicine clinic, and the UCDHS in-person clinic. Travel cost savings and environmental impact were calculated by determining differences in mileage reimbursement rate and emissions between those incurred in attending telemedicine appointments and those that would have been incurred if a visit to the hub site had been necessary. There were 19,246 consultations identified among 11,281 unique patients. Telemedicine visits resulted in a total travel distance savings of 5,345,602 miles, a total travel time savings of 4,708,891 minutes or 8.96 years, and a total direct travel cost savings of $2,882,056. The mean per-consultation round-trip distance savings were 278 miles, average travel time savings were 245 minutes, and average cost savings were $156. Telemedicine consultations resulted in a total emissions savings of 1969 metric tons of CO 2 , 50 metric tons of CO, 3.7 metric tons of NO x , and 5.5 metric tons of volatile organic compounds. This study demonstrates the positive impact of a health system's outpatient telemedicine program on patient travel time, patient travel costs, and environmental pollutants. Copyright © 2017 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  14. Improving value of travel time savings estimation for more effective transportation project evaluation : [summary].

    Science.gov (United States)

    2012-01-01

    The daily commute to a job is a cost of working. Workers may share stories about the extent or rigors of their commute, or they may enjoy the time with reading, music, or drive-time radio personalities. For any trip, many factors contribute to a trav...

  15. The Desired Quality of Integrated Multimodal Travel Information in Public Transport: Customer Needs for Time and Effort Savings

    NARCIS (Netherlands)

    Grotenhuis, J-W.; Wiegmans, B.; Rietveld, P.

    2007-01-01

    Travel information is one of the factors that contribute to the quality of public transport. In particular, integrated multimodal travel information (IMTI) is expected to affect customers' modal choice. The objective of this research is to identify customers' desired quality of IMTI provision in

  16. Modelling urban travel times

    NARCIS (Netherlands)

    Zheng, F.

    2011-01-01

    Urban travel times are intrinsically uncertain due to a lot of stochastic characteristics of traffic, especially at signalized intersections. A single travel time does not have much meaning and is not informative to drivers or traffic managers. The range of travel times is large such that certain

  17. Publishers: Save Authors' Time.

    Science.gov (United States)

    Moustafa, Khaled

    2017-02-02

    Scientific journals ask authors to put their manuscripts, at the submission stage, sometimes in a complex style and a specific pagination format that are time consuming while it is unclear yet that the submitted manuscripts will be accepted. In the case of rejections, authors need to submit to another journal most likely with a different style and formatting that require additional work and time. To save authors' time, publishers should allow authors to submit their manuscripts in any format and to comply with the style required by the targeted journal only in revised versions, but not at the submission step when the manuscripts are not yet approved for publication.

  18. Travel time data collection handbook

    Science.gov (United States)

    1998-03-01

    This Travel Time Data Collection Handbook provides guidance to transportation : professionals and practitioners for the collection, reduction, and presentation : of travel time data. The handbook should be a useful reference for designing : travel ti...

  19. Travel time reliability modeling.

    Science.gov (United States)

    2011-07-01

    This report includes three papers as follows: : 1. Guo F., Rakha H., and Park S. (2010), "A Multi-state Travel Time Reliability Model," : Transportation Research Record: Journal of the Transportation Research Board, n 2188, : pp. 46-54. : 2. Park S.,...

  20. Travel time and travel cost in European air travel

    OpenAIRE

    Dusek, Tamas

    2012-01-01

    The aim of the study is to examine two issues of consumer air travel accessibility in Europe, namely flight time and ticket costs. The first part of the paper discusses the various methodological problems of creating time matrix and cost matrix of air travel. Because of problems of conceptualizing of the air travel network and the modifiable areal unit problem the analysis is conducted on several spatial levels. The smallest network consists of 15 busiest airports and the largest network has ...

  1. Time travel a history

    CERN Document Server

    Gleick, James

    2016-01-01

    From the acclaimed author of The Information and Chaos, here is a mind-bending exploration of time travel: its subversive origins, its evolution in literature and science, and its influence on our understanding of time itself. The story begins at the turn of the previous century, with the young H. G. Wells writing and rewriting the fantastic tale that became his first book and an international sensation: The Time Machine. It was an era when a host of forces was converging to transmute the human understanding of time, some philosophical and some technological: the electric telegraph, the steam railroad, the discovery of buried civilizations, and the perfection of clocks. James Gleick tracks the evolution of time travel as an idea that becomes part of contemporary culture—from Marcel Proust to Doctor Who, from Jorge Luis Borges to Woody Allen. He investigates the inevitable looping paradoxes and examines the porous boundary between pulp fiction and modern physics. Finally, he delves into a temporal shift that...

  2. Estimated time of arrival and debiasing the time saving bias.

    Science.gov (United States)

    Eriksson, Gabriella; Patten, Christopher J D; Svenson, Ola; Eriksson, Lars

    2015-01-01

    The time saving bias predicts that the time saved when increasing speed from a high speed is overestimated, and underestimated when increasing speed from a slow speed. In a questionnaire, time saving judgements were investigated when information of estimated time to arrival was provided. In an active driving task, an alternative meter indicating the inverted speed was used to debias judgements. The simulated task was to first drive a distance at a given speed, and then drive the same distance again at the speed the driver judged was required to gain exactly 3 min in travel time compared with the first drive. A control group performed the same task with a speedometer and saved less than the targeted 3 min when increasing speed from a high speed, and more than 3 min when increasing from a low speed. Participants in the alternative meter condition were closer to the target. The two studies corroborate a time saving bias and show that biased intuitive judgements can be debiased by displaying the inverted speed. Practitioner Summary: Previous studies have shown a cognitive bias in judgements of the time saved by increasing speed. This simulator study aims to improve driver judgements by introducing a speedometer indicating the inverted speed in active driving. The results show that the bias can be reduced by presenting the inverted speed and this finding can be used when designing in-car information systems.

  3. Approaches to groundwater travel time

    International Nuclear Information System (INIS)

    Kaplan, P.; Klavetter, E.; Peters, R.

    1989-01-01

    One of the objectives of performance assessment for the Yucca Mountain Project is to estimate the groundwater travel time at Yucca Mountain, Nevada, to determine whether the site complies with the criteria specified in the Code of Federal Regulations, Title 10 CFR 60.113 (a). The numerical standard for performance in these criteria is based on the groundwater travel time along the fastest path of likely radionuclide transport from the disturbed zone to the accessible environment. The concept of groundwater travel time as proposed in the regulations, does not have a unique mathematical statement. The purpose of this paper is to discuss the ambiguities associated with the regulatory specification of groundwater travel time, two different interpretations of groundwater travel time, and the effect of the two interpretations on estimates of the groundwater travel time

  4. Calculation of groundwater travel time

    International Nuclear Information System (INIS)

    Arnett, R.C.; Sagar, B.; Baca, R.G.

    1984-12-01

    Pre-waste-emplacement groundwater travel time is one indicator of the isolation capability of the geologic system surrounding a repository. Two distinct modeling approaches exist for prediction of groundwater flow paths and travel times from the repository location to the designated accessible environment boundary. These two approaches are: (1) the deterministic approach which calculates a single value prediction of groundwater travel time based on average values for input parameters and (2) the stochastic approach which yields a distribution of possible groundwater travel times as a function of the nature and magnitude of uncertainties in the model inputs. The purposes of this report are to (1) document the theoretical (i.e., mathematical) basis used to calculate groundwater pathlines and travel times in a basalt system, (2) outline limitations and ranges of applicability of the deterministic modeling approach, and (3) explain the motivation for the use of the stochastic modeling approach currently being used to predict groundwater pathlines and travel times for the Hanford Site. Example calculations of groundwater travel times are presented to highlight and compare the differences between the deterministic and stochastic modeling approaches. 28 refs

  5. Travel time estimation using Bluetooth.

    Science.gov (United States)

    2015-06-01

    The objective of this study was to investigate the feasibility of using a Bluetooth Probe Detection System (BPDS) to : estimate travel time in an urban area. Specifically, the study investigated the possibility of measuring overall congestion, the : ...

  6. Ground-water travel time

    International Nuclear Information System (INIS)

    Bentley, H.; Grisak, G.

    1985-01-01

    The Containment and Isolation Working Group considered issues related to the postclosure behavior of repositories in crystalline rock. This working group was further divided into subgroups to consider the progress since the 1978 GAIN Symposium and identify research needs in the individual areas of regional ground-water flow, ground-water travel time, fractional release, and cumulative release. The analysis and findings of the Ground-Water Travel Time Subgroup are presented

  7. Travel time variability and rational inattention

    DEFF Research Database (Denmark)

    Fosgerau, Mogens; Jiang, Gege

    2017-01-01

    This paper sets up a rational inattention model for the choice of departure time for a traveler facing random travel time. The traveler chooses how much information to acquire about the travel time out-come before choosing departure time. This reduces the cost of travel time variability compared...

  8. Monitoring Travel Time Reliability on Freeways

    NARCIS (Netherlands)

    Tu, Huizhao

    2008-01-01

    Travel time and travel time reliability are important attributes of a trip. The current measures of reliability have in common that in general they all relate to the variability of travel times. However, travel time reliability does not only rely on variability but also on the stability of travel

  9. Valuation of Travel Time and TravelIer Information

    OpenAIRE

    Piet Rietveld

    2003-01-01

    The value of travel time plays an important role in cost benefit analysis of infrastructureprojects. However, the issue of uncertainty on travel times and the implications this has forestimations of travel time values has received much less attention in the literature. In thispaper we compare various modelling approaches to address uncertainty and demonstrate thatignoring uncertainty issues may easily lead to distorted estimates of values of travel time. Thisis of special relevance in public ...

  10. The value of travel time variance

    OpenAIRE

    Fosgerau, Mogens; Engelson, Leonid

    2010-01-01

    This paper considers the value of travel time variability under scheduling preferences that are de�fined 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 ...

  11. Valuation of Travel Time and TravelIer Information

    NARCIS (Netherlands)

    Rietveld, Piet

    2003-01-01

    The value of travel time plays an important role in cost benefit analysis of infrastructureprojects. However, the issue of uncertainty on travel times and the implications this has forestimations of travel time values has received much less attention in the literature. In thispaper we compare

  12. Forbidden time travel

    DEFF Research Database (Denmark)

    Nøjgaard, Nikolai; Geiß, Manuela; Merkle, Daniel

    2017-01-01

    tree T with a species trees S, relative to the reconciliation problem without prior knowledge of the event types. It is well-known that optimal reconciliations in the unlabeled case may violate time-consistency and thus are not biologically feasible. Here we investigate the mathematical structure...... of the event labeled reconciliation problem with horizontal transfer. Results: We investigate the issue of time-consistency for the event-labeled version of the reconciliation problem, provide a convenient axiomatic framework, and derive a complete characterization of time-consistent reconciliations....... This characterization depends on certain weak conditions on the event-labeled gene trees that reflect conditions under which evolutionary events are observable at least in principle. We give an O(|V (T)| log(|V (S)|))-time algorithm to decide whether a time-consistent reconciliation map exists. It does not require...

  13. Time Travel in the Library

    Science.gov (United States)

    Brown, Donna W.

    2005-01-01

    A Time Travel project in the library gives enthusiasm to students to connect with the past and reinforces their research skills while instilling respect for the past years. The librarian should choose one specific decade to highlight in the library and create an extravaganza that would allow memorabilia from that time period to be located without…

  14. 5 CFR 630.207 - Travel time.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Travel time. 630.207 Section 630.207... and General Provisions for Annual and Sick Leave § 630.207 Travel time. The travel time granted an... occupied in traveling to and from his post of duty and (a) the United States, or (b) his place of residence...

  15. Fellow travellers: Working memory and mental time travel in rodents.

    Science.gov (United States)

    Dere, Ekrem; Dere, Dorothea; de Souza Silva, Maria Angelica; Huston, Joseph P; Zlomuzica, Armin

    2017-03-19

    The impairment of mental time travel is a severe cognitive symptom in patients with brain lesions and a number of neuropsychiatric disorders. Whether animals are also able to mentally travel in time both forward and backward is still a matter of debate. In this regard, we have proposed a continuum of mental time travel abilities across different animal species, with humans being the species with the ability to perform most sophisticated forms of mental time travel. In this review and perspective article, we delineate a novel approach to understand the evolution, characteristics and function of human and animal mental time travel. Furthermore, we propose a novel approach to measure mental time travel in rodents in a comprehensive manner using a test battery composed of well-validated and easy applicable tests. Copyright © 2017. Published by Elsevier B.V.

  16. Floating / Travelling Gardens of (Postcolonial Time

    Directory of Open Access Journals (Sweden)

    Carmen Concilio

    2017-11-01

    Full Text Available This essay on travelling gardens of (postcolonial time opens with two iconic images of floating gardens in contemporary postcolonial literature: Will Phantom’s bio-garbage rafter, which saves him in the midst of a cyclone in Carpentaria (2008, by the Aboriginal author Alexis Wright, and Pi’s carnivore island-organism in Life of Pi (2001, which cannot save him from his shipwreck, by Canadian writer Yan Martel. These floating, hybrid gardens of the Anthropocene precede the real travelling gardens of both Michael Ondaatje’s The Cat’s Table (2011 and Amitav Ghosh’s Ibis Trilogy (2008-2015, two authors who both indirectly and directly tell the story of botanical gardens in Asia, and of plant and seed smuggling and transplantation (“displacement” also hinting at their historical and economic colonial implications. For, after all, botanical gardens imply a very specific version of care, Cura (Robert Pogue Harrison 2009, while embodying a precise, imperial scientific and economic project (Brockway 2002; Johnson 2011.

  17. Dynamic travel time estimation using regression trees.

    Science.gov (United States)

    2008-10-01

    This report presents a methodology for travel time estimation by using regression trees. The dissemination of travel time information has become crucial for effective traffic management, especially under congested road conditions. In the absence of c...

  18. 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....

  19. Accurate estimation of indoor travel times

    DEFF Research Database (Denmark)

    Prentow, Thor Siiger; Blunck, Henrik; Stisen, Allan

    2014-01-01

    The ability to accurately estimate indoor travel times is crucial for enabling improvements within application areas such as indoor navigation, logistics for mobile workers, and facility management. In this paper, we study the challenges inherent in indoor travel time estimation, and we propose...... the InTraTime method for accurately estimating indoor travel times via mining of historical and real-time indoor position traces. The method learns during operation both travel routes, travel times and their respective likelihood---both for routes traveled as well as for sub-routes thereof. In......TraTime allows to specify temporal and other query parameters, such as time-of-day, day-of-week or the identity of the traveling individual. As input the method is designed to take generic position traces and is thus interoperable with a variety of indoor positioning systems. The method's advantages include...

  20. 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 ...... 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.......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...

  1. Network structure and travel time perception.

    Science.gov (United States)

    Parthasarathi, Pavithra; Levinson, David; Hochmair, Hartwig

    2013-01-01

    The purpose of this research is to test the systematic variation in the perception of travel time among travelers and relate the variation to the underlying street network structure. Travel survey data from the Twin Cities metropolitan area (which includes the cities of Minneapolis and St. Paul) is used for the analysis. Travelers are classified into two groups based on the ratio of perceived and estimated commute travel time. The measures of network structure are estimated using the street network along the identified commute route. T-test comparisons are conducted to identify statistically significant differences in estimated network measures between the two traveler groups. The combined effect of these estimated network measures on travel time is then analyzed using regression models. The results from the t-test and regression analyses confirm the influence of the underlying network structure on the perception of travel time.

  2. [Mental Space Navigation and Mental Time Travel].

    Science.gov (United States)

    Kawamura, Mitsuru

    2017-11-01

    We examined patients with mental space navigation or mental time travel disorder to identify regions in the brain that may play a critical role in mental time travel in terms of clinical neuropsychology. These regions included the precneus, posterior cingulate gyrus, retrosplenial cortex, and hippocampus, as well as the orbitofrontal cortex: the anterior and posterior medial areas were both shown to be important in this process. Further studies are required to define whether these form a network for mental time travel.

  3. The cost of travel time variability

    DEFF Research Database (Denmark)

    Engelson, Leonid; Fosgerau, Mogens

    2016-01-01

    This paper explores the relationships between three types of measures of the cost of travel time variability: measures based on scheduling preferences and implicit departure time choice, Bernoulli type measures based on a univariate function of travel time, and mean-dispersion measures. We...

  4. Travel time variability and airport accessibility

    OpenAIRE

    Koster, P.R.; Kroes, E.P.; Verhoef, E.T.

    2010-01-01

    This discussion paper resulted in a publication in Transportation Research Part B: Methodological (2011). Vol. 45(10), pages 1545-1559. This paper analyses the cost of access travel time variability for air travelers. Reliable access to airports is important since it is likely that the cost of missing a flight is high. First, the determinants of the preferred arrival times at airports are analyzed, including trip purpose, type of airport, flight characteristics, travel experience, type of che...

  5. Valuing travel time variability: Characteristics of the travel time distribution on an urban road

    DEFF Research Database (Denmark)

    Fosgerau, Mogens; Fukuda, Daisuke

    2012-01-01

    This paper provides a detailed empirical investigation of the distribution of travel times on an urban road for valuation of travel time variability. Our investigation is premised on the use of a theoretical model with a number of desirable properties. The definition of the value of travel time...... variability depends on certain properties of the distribution of random travel times that require empirical verification. Applying a range of nonparametric statistical techniques to data giving minute-by-minute travel times for a congested urban road over a period of five months, we show that the standardized...... travel time is roughly independent of the time of day as required by the theory. Except for the extreme right tail, a stable distribution seems to fit the data well. The travel time distributions on consecutive links seem to share a common stability parameter such that the travel time distribution...

  6. Travel time variability and airport accessibility

    NARCIS (Netherlands)

    Koster, P.R.; Kroes, E.P.; Verhoef, E.T.

    2011-01-01

    We analyze the cost of access travel time variability for air travelers. Reliable access to airports is important since the cost of missing a flight is likely to be high. First, the determinants of the preferred arrival times at airports are analyzed. Second, the willingness to pay (WTP) for

  7. Ocean acoustic tomography - Travel time biases

    Science.gov (United States)

    Spiesberger, J. L.

    1985-01-01

    The travel times of acoustic rays traced through a climatological sound-speed profile are compared with travel times computed through the same profile containing an eddy field. The accuracy of linearizing the relations between the travel time difference and the sound-speed deviation at long ranges is assessed using calculations made for two different eddy fields measured in the eastern Atlantic. Significant nonlinearities are found in some cases, and the relationships of the values of these nonlinearities to the range between source and receiver, to the anomaly size associated with the eddies, and to the positions of the eddies are studied. An analytical model of the nonlinearities is discussed.

  8. On the income elasticity of the value of travel time

    DEFF Research Database (Denmark)

    Börjesson, Maria; Fosgerau, Mogens; Algers, Staffan

    2012-01-01

    Transport infrastructure is long-term and in appraisal it is necessary to value travel time savings for future years. This requires knowing how the value of time (VTT) will develop over time as incomes grow. This paper investigates if the cross-sectional income elasticity of the VTT is equal...... to inter-temporal income elasticity. The study is based on two identical stated choice experiments conducted with a 13 year interval. Results indicate that the relationship between income and the VTT in the cross-section has remained unchanged over time. As a consequence, the inter-temporal income...... be expected to increase further over time....

  9. Multimodal Network Equilibrium with Stochastic Travel Times

    Directory of Open Access Journals (Sweden)

    M. Meng

    2014-01-01

    Full Text Available The private car, unlike public traffic modes (e.g., subway, trolley running along dedicated track-ways, is invariably subject to various uncertainties resulting in travel time variation. A multimodal network equilibrium model is formulated that explicitly considers stochastic link capacity variability in the road network. The travel time of combined-mode trips is accumulated based on the concept of the mean excess travel time (METT which is a summation of estimated buffer time and tardy time. The problem is characterized by an equivalent VI (variational inequality formulation where the mode choice is expressed in a hierarchical logit structure. Specifically, the supernetwork theory and expansion technique are used herein to represent the multimodal transportation network, which completely represents the combined-mode trips as constituting multiple modes within a trip. The method of successive weighted average is adopted for problem solutions. The model and solution method are further applied to study the trip distribution and METT variations caused by the different levels of the road conditions. Results of numerical examples show that travelers prefer to choose the combined travel mode as road capacity decreases. Travelers with different attitudes towards risk are shown to exhibit significant differences when making travel choice decisions.

  10. Highway travel time estimation with data fusion

    CERN Document Server

    Soriguera Martí, Francesc

    2016-01-01

    This monograph presents a simple, innovative approach for the measurement and short-term prediction of highway travel times based on the fusion of inductive loop detector and toll ticket data. The methodology is generic and not technologically captive, allowing it to be easily generalized for other equivalent types of data. The book shows how Bayesian analysis can be used to obtain fused estimates that are more reliable than the original inputs, overcoming some of the drawbacks of travel-time estimations based on unique data sources. The developed methodology adds value and obtains the maximum (in terms of travel time estimation) from the available data, without recurrent and costly requirements for additional data. The application of the algorithms to empirical testing in the AP-7 toll highway in Barcelona proves that it is possible to develop an accurate real-time, travel-time information system on closed-toll highways with the existing surveillance equipment, suggesting that highway operators might provide...

  11. Freeway travel-time estimation and forecasting.

    Science.gov (United States)

    2012-09-01

    This project presents a microsimulation-based framework for generating short-term forecasts of travel time on freeway corridors. The microsimulation model that is developed (GTsim), replicates freeway capacity drop and relaxation phenomena critical f...

  12. Establishing monitoring programs for travel time reliability.

    Science.gov (United States)

    2014-01-01

    Within the second Strategic Highway Research Program (SHRP 2), Project L02 focused on creating a suite of methods by which transportation agencies could monitor and evaluate travel time reliability. Creation of the methods also produced an improved u...

  13. Advisory Systems Save Time, Fuel for Airlines

    Science.gov (United States)

    2012-01-01

    Heinz Erzberger never thought the sky was falling, but he knew it could benefit from enhanced traffic control. Throughout the 1990s, Erzberger led a team at Ames Research Center to develop a suite of automated tools to reduce restrictions and improve the efficiency of air traffic control operations. Called CTAS, or Center-TRACON (Terminal Radar Approach Control) Automation System, the software won NASA s Software of the Year award in 1998, and one of the tools in the suite - the traffic management advisor - was adopted by the Federal Aviation Administration and implemented at traffic control centers across the United States. Another one of the tools, Direct-To, has followed a different path. The idea behind Direct-To, explains Erzberger, a senior scientist at Ames, was that airlines could save fuel and money by shortening the routes they flew between take-off and landing. Aircraft are often limited to following established airways comprised of inefficient route segments. The routes are not easily adjusted because neither the pilot nor the aircraft controller can anticipate the constantly changing air traffic situation. To make the routes more direct while in flight, Erzberger came up with an idea for a software algorithm that could automatically examine air traffic in real-time, check to see if a shortcut was available, and then check for conflicts. If there were no conflicts and the shortcut saved more than 1 minute of flight time, the controller could be notified. "I was trying to figure out what goes on in the pilot and controller s minds when they decide to guide the aircraft in a certain way. That resulted in a different kind analysis," Erzberger says. As the engineer s idea went from theory to practice, in 2001, NASA demonstrated Direct-To in the airspace of Dallas-Ft. Worth. Estimations based on the demonstration found the technology was capable of saving 900 flying minutes per day for the aircraft in the test area.

  14. 5 CFR 550.1404 - Creditable travel time.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Creditable travel time. 550.1404 Section... ADMINISTRATION (GENERAL) Compensatory Time Off for Travel § 550.1404 Creditable travel time. (a) General. Subject... off for time in a travel status if— (1) The employee is required to travel away from the official duty...

  15. Geostatistical evaluation of travel time uncertainties

    International Nuclear Information System (INIS)

    Devary, J.L.

    1983-08-01

    Data on potentiometric head and hydraulic conductivity, gathered from the Wolfcamp Formation of the Permian System, have exhibited tremendous spatial variability as a result of heterogeneities in the media and the presence of petroleum and natural gas deposits. Geostatistical data analysis and error propagation techniques (kriging and conditional simulation) were applied to determine the effect of potentiometric head uncertainties on radionuclide travel paths and travel times through the Wolfcamp Formation. Blok-average kriging was utilized to remove measurement error from potentiometric head data. The travel time calculations have been enhanced by the use of an inverse technique to determine the relative hydraulic conductivity along travel paths. In this way, the spatial variability of the hydraulic conductivity corresponding to streamline convergence and divergence may be included in the analysis. 22 references, 11 figures, 1 table

  16. On the relationship between travel time and travel distance of commuters. Reported versus network travel data in the Netherlands

    NARCIS (Netherlands)

    Rietveld, P.; Zwart, B.; van Wee, B.; van Hoorn, T.

    1999-01-01

    This paper gives a detailed empirical analysis of the relationships between different indicators of costs of commuting trips by car: difference as the crow flies, shortest travel time according to route planner, corresponding travel distance, and reported travel time. Reported travel times are

  17. Contact Frequency, Travel Time, and Travel Costs for Patients with Rheumatoid Arthritis

    OpenAIRE

    Sørensen, Jan; Linde, Louise; Hetland, Merete Lund

    2014-01-01

    Objectives. To investigate travel time, and travel cost related to contacts with health care providers for patients with rheumatoid arthritis (RA) during a three-month period. Methods. Patient-reported travel time and travel cost were obtained from 2847 patients with RA. Eleven outpatient clinics across Denmark recruited patients to the study. Data collected included frequency, travel time and travel costs for contacts at rheumatology outpatient clinics, other outpatient clinics, general prac...

  18. Research on Energy-Saving Design of Overhead Travelling Crane Camber Based on Probability Load Distribution

    Directory of Open Access Journals (Sweden)

    Tong Yifei

    2014-01-01

    Full Text Available Crane is a mechanical device, used widely to move materials in modern production. It is reported that the energy consumptions of China are at least 5–8 times of other developing countries. Thus, energy consumption becomes an unavoidable topic. There are several reasons influencing the energy loss, and the camber of the girder is the one not to be neglected. In this paper, the problem of the deflections induced by the moving payload in the girder of overhead travelling crane is examined. The evaluation of a camber giving a counterdeflection of the girder is proposed in order to get minimum energy consumptions for trolley to move along a nonstraight support. To this aim, probabilistic payload distributions are considered instead of fixed or rated loads involved in other researches. Taking 50/10 t bridge crane as a research object, the probability loads are determined by analysis of load distribution density functions. According to load distribution, camber design under different probability loads is discussed in detail as well as energy consumptions distribution. The research results provide the design reference of reasonable camber to obtain the least energy consumption for climbing corresponding to different P0; thus energy-saving design can be achieved.

  19. A constant travel time budget? In search for explanations for an increase in average travel time

    NARCIS (Netherlands)

    Rietveld, P.; Wee, van B.

    2002-01-01

    Recent research suggests that during the past decades the average travel time of the Dutch population has probably increased. However, different datasources show different levels of increase. Possible causes of the increase in average travel time are presented here. Increased incomes have

  20. On the relationship between travel time and travel distance in the Netherlands

    NARCIS (Netherlands)

    Rietveld, P.; Zwart, B.; van Wee, B.; van der Hoorn, A.I.J.M.

    1999-01-01

    This paper gives a detailed empirical analysis of the relationships between different indicators of costs of commuting trips by car: difference as the crow flies, shortest travel time according to route planner, corresponding travel distance, and reported travel time. Reported travel times are

  1. Effectiveness of different approaches to disseminating traveler information on travel time reliability. [supporting datasets

    Science.gov (United States)

    2013-11-30

    Travel time reliability information includes static data about traffic speeds or trip times that capture historic variations from day to day, and it can help individuals understand the level of variation in traffic. Unlike real-time travel time infor...

  2. 5 CFR 551.422 - Time spent traveling.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Time spent traveling. 551.422 Section 551... Activities § 551.422 Time spent traveling. (a) Time spent traveling shall be considered hours of work if: (1... who is permitted to use an alternative mode of transportation, or an employee who travels at a time...

  3. Empirical Study of Travel Time Estimation and Reliability

    OpenAIRE

    Li, Ruimin; Chai, Huajun; Tang, Jin

    2013-01-01

    This paper explores the travel time distribution of different types of urban roads, the link and path average travel time, and variance estimation methods by analyzing the large-scale travel time dataset detected from automatic number plate readers installed throughout Beijing. The results show that the best-fitting travel time distribution for different road links in 15 min time intervals differs for different traffic congestion levels. The average travel time for all links on all days can b...

  4. Navigation API Route Fuel Saving Opportunity Assessment on Large-Scale Real-World Travel Data for Conventional Vehicles and Hybrid Electric Vehicles: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Lei [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Holden, Jacob [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Gonder, Jeffrey D [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-12-06

    The green routing strategy instructing a vehicle to select a fuel-efficient route benefits the current transportation system with fuel-saving opportunities. This paper introduces a navigation API route fuel-saving evaluation framework for estimating fuel advantages of alternative API routes based on large-scale, real-world travel data for conventional vehicles (CVs) and hybrid electric vehicles (HEVs). The navigation APIs, such Google Directions API, integrate traffic conditions and provide feasible alternative routes for origin-destination pairs. This paper develops two link-based fuel-consumption models stratified by link-level speed, road grade, and functional class (local/non-local), one for CVs and the other for HEVs. The link-based fuel-consumption models are built by assigning travel from a large number of GPS driving traces to the links in TomTom MultiNet as the underlying road network layer and road grade data from a U.S. Geological Survey elevation data set. Fuel consumption on a link is calculated by the proposed fuel consumption model. This paper envisions two kinds of applications: 1) identifying alternate routes that save fuel, and 2) quantifying the potential fuel savings for large amounts of travel. An experiment based on a large-scale California Household Travel Survey GPS trajectory data set is conducted. The fuel consumption and savings of CVs and HEVs are investigated. At the same time, the trade-off between fuel saving and time saving for choosing different routes is also examined for both powertrains.

  5. Travel Time Estimation on Urban Street Segment

    Directory of Open Access Journals (Sweden)

    Jelena Kajalić

    2018-02-01

    Full Text Available Level of service (LOS is used as the main indicator of transport quality on urban roads and it is estimated based on the travel speed. The main objective of this study is to determine which of the existing models for travel speed calculation is most suitable for local conditions. The study uses actual data gathered in travel time survey on urban streets, recorded by applying second by second GPS data. The survey is limited to traffic flow in saturated conditions. The RMSE method (Root Mean Square Error is used for research results comparison with relevant models: Akcelik, HCM (Highway Capacity Manual, Singapore model and modified BPR (the Bureau of Public Roads function (Dowling - Skabardonis. The lowest deviation in local conditions for urban streets with standardized intersection distance (400-500 m is demonstrated by Akcelik model. However, for streets with lower signal density (<1 signal/km the correlation between speed and degree of saturation is best presented by HCM and Singapore model. According to test results, Akcelik model was adopted for travel speed estimation which can be the basis for determining the level of service in urban streets with standardized intersection distance and coordinated signal timing under local conditions.

  6. On the relationship between travel time and travel distance of commuters. Reported versus network travel data in the Netherlands

    OpenAIRE

    Rietveld, P.; Zwart, B.; van Wee, B.; van Hoorn, T.

    1999-01-01

    This paper gives a detailed empirical analysis of the relationships between different indicators of costs of commuting trips by car: difference as the crow flies, shortest travel time according to route planner, corresponding travel distance, and reported travel time. Reported travel times are usually rounded in multiples of five minutes. This calls for special statistical techniques. Ignoring the phenomenon of rounding leads to biased estimation results for shorter distances. Rather surprisi...

  7. Do You Automate? Saving Time and Dollars

    Science.gov (United States)

    Carmichael, Christine H.

    2010-01-01

    An automated workforce management strategy can help schools save jobs, improve the job satisfaction of teachers and staff, and free up precious budget dollars for investments in critical learning resources. Automated workforce management systems can help schools control labor costs, minimize compliance risk, and improve employee satisfaction.…

  8. Inferring Saving in Training Time From Effect Size Estimates

    National Research Council Canada - National Science Library

    Burright, Burke

    2000-01-01

    .... Students' time saving represents a major potential benefit of using them. This paper fills a methodology gap in estimating the students' timesaving benefit of asynchronous training technologies...

  9. A methodology for rearranging transit stops for enhancing transit users generalized travel time

    Directory of Open Access Journals (Sweden)

    Mohammad Nurul Hassan

    2017-02-01

    Full Text Available This study develops a methodology to consolidate transit stops. It develops a mathematical model and a program which takes stop consolidation decision(s according to users generalized travel time savings and desired accessibility. The model iterates until the users generalized travel time savings are maximized. The study tests this mathematical model in different hypothetical scenarios. Six factors (distance between stops, passenger activity, average cruising speed, maximum walking distance, service frequency, and percentage of decreased passengers with multiple levels were set to build the scenarios. Three responses (percentage of consolidated stops, percentages of travel time and operating time savings were observed. The findings showed that the distance between the stops the passenger activity, and the probable demand change (or the percentage of decreased passengers are the most influential factors. The frequency of service was found to be influential as well. The average cruising speed has very little influence on the response variables. Finally, the model is tested on two routes (route 900 and 930 of Al Ain City public bus service. It shows that 22 and 32 out of 98 and 126 stops can be consolidated in route 900 and 930 respectively. This can save considerable amounts of users travel and operating times. In monetary values, the savings are about $329,827 and $491,094 per year for routes 900 and 930, respectively.

  10. Impact of connected vehicle guidance information on network-wide average travel time

    Directory of Open Access Journals (Sweden)

    Jiangfeng Wang

    2016-12-01

    Full Text Available With the emergence of connected vehicle technologies, the potential positive impact of connected vehicle guidance on mobility has become a research hotspot by data exchange among vehicles, infrastructure, and mobile devices. This study is focused on micro-modeling and quantitatively evaluating the impact of connected vehicle guidance on network-wide travel time by introducing various affecting factors. To evaluate the benefits of connected vehicle guidance, a simulation architecture based on one engine is proposed representing the connected vehicle–enabled virtual world, and connected vehicle route guidance scenario is established through the development of communication agent and intelligent transportation systems agents using connected vehicle application programming interface considering the communication properties, such as path loss and transmission power. The impact of connected vehicle guidance on network-wide travel time is analyzed by comparing with non-connected vehicle guidance in response to different market penetration rate, following rate, and congestion level. The simulation results explore that average network-wide travel time in connected vehicle guidance shows a significant reduction versus that in non–connected vehicle guidance. Average network-wide travel time in connected vehicle guidance have an increase of 42.23% comparing to that in non-connected vehicle guidance, and average travel time variability (represented by the coefficient of variance increases as the travel time increases. Other vital findings include that higher penetration rate and following rate generate bigger savings of average network-wide travel time. The savings of average network-wide travel time increase from 17% to 38% according to different congestion levels, and savings of average travel time in more serious congestion have a more obvious improvement for the same penetration rate or following rate.

  11. Travel Time to Hospital for Childbirth: Comparing Calculated Versus Reported Travel Times in France.

    Science.gov (United States)

    Pilkington, Hugo; Prunet, Caroline; Blondel, Béatrice; Charreire, Hélène; Combier, Evelyne; Le Vaillant, Marc; Amat-Roze, Jeanne-Marie; Zeitlin, Jennifer

    2018-01-01

    Objectives Timely access to health care is critical in obstetrics. Yet obtaining reliable estimates of travel times to hospital for childbirth poses methodological challenges. We compared two measures of travel time, self-reported and calculated, to assess concordance and to identify determinants of long travel time to hospital for childbirth. Methods Data came from the 2010 French National Perinatal Survey, a national representative sample of births (N = 14 681). We compared both travel time measures by maternal, maternity unit and geographic characteristics in rural, peri-urban and urban areas. Logistic regression models were used to study factors associated with reported and calculated times ≥30 min. Cohen's kappa coefficients were also calculated to estimate the agreement between reported and calculated times according to women's characteristics. Results In urban areas, the proportion of women with travel times ≥30 min was higher when reported rather than calculated times were used (11.0 vs. 3.6%). Longer reported times were associated with non-French nationality [adjusted odds ratio (aOR) 1.3 (95% CI 1.0-1.7)] and inadequate prenatal care [aOR 1.5 (95% CI 1.2-2.0)], but not for calculated times. Concordance between the two measures was higher in peri-urban and rural areas (52.4 vs. 52.3% for rural areas). Delivery in a specialised level 2 or 3 maternity unit was a principal determinant of long reported and measured times in peri-urban and rural areas. Conclusions for Practice The level of agreement between reported and calculated times varies according to geographic context. Poor measurement of travel time in urban areas may mask problems in accessibility.

  12. Saving Money and Time with Virtual Server

    CERN Document Server

    Sanders, Chris

    2006-01-01

    Microsoft Virtual Server 2005 consistently proves to be worth its weight in gold, with new implementations thought up every day. With this product now a free download from Microsoft, scores of new users are able to experience what the power of virtualization can do for their networks. This guide is aimed at network administrators who are interested in ways that Virtual Server 2005 can be implemented in their organizations in order to save money and increase network productivity. It contains information on setting up a virtual network, virtual consolidation, virtual security, virtual honeypo

  13. Analysis of travel time reliability on Indiana interstates.

    Science.gov (United States)

    2009-09-15

    Travel-time reliability is a key performance measure in any transportation system. It is a : measure of quality of travel time experienced by transportation system users and reflects the efficiency : of the transportation system to serve citizens, bu...

  14. Incorporating travel time reliability into the Highway Capacity Manual.

    Science.gov (United States)

    2014-01-01

    This final report documents the activities performed during SHRP 2 Reliability Project L08: Incorporating Travel Time Reliability into the Highway Capacity Manual. It serves as a supplement to the proposed chapters for incorporating travel time relia...

  15. Travel Time Data Collection Field Tests - Lessons Learned

    Science.gov (United States)

    1996-01-01

    This report summarizes the process and lessons learned from the Standardized Travel Time Surveys and Field Test project. The field tests of travel time data collection were conducted in Boston, Seattle, and Lexington in 1993. The methodologies tested...

  16. Contact frequency, travel time, and travel costs for patients with rheumatoid arthritis

    DEFF Research Database (Denmark)

    Sørensen, Jan; Linde, Louise; Hetland, Merete Lund

    2014-01-01

    Objectives. To investigate travel time, and travel cost related to contacts with health care providers for patients with rheumatoid arthritis (RA) during a three-month period. Methods. Patient-reported travel time and travel cost were obtained from 2847 patients with RA. Eleven outpatient clinics...... across Denmark recruited patients to the study. Data collected included frequency, travel time and travel costs for contacts at rheumatology outpatient clinics, other outpatient clinics, general practitioners, privately practicing medical specialists, inpatient hospitals and accident and emergency...... departments. Results. Over a 3-month period, patients with RA had on average 4.4 (sd 5.7) contacts with health care providers, of which 2.8 (sd 4.0) contacts were with rheumatology outpatient clinics. Private car and public travel were the most frequent modes of travel. The average patient spent 63 minutes...

  17. Consumption and Savings of First Time House Owners

    DEFF Research Database (Denmark)

    Ejarque, João; Leth-Petersen, Søren

    We characterize savings behavior around the point of the first house purchase. Using a panel data set with income and wealth information on Danish first-time house owners we document that households save for the down payment, mortgage to the limit, run down liquid assets at purchase, and adjust...

  18. Connected Traveler

    Energy Technology Data Exchange (ETDEWEB)

    2016-06-01

    The Connected Traveler framework seeks to boost the energy efficiency of personal travel and the overall transportation system by maximizing the accuracy of predicted traveler behavior in response to real-time feedback and incentives. It is anticipated that this approach will establish a feedback loop that 'learns' traveler preferences and customizes incentives to meet or exceed energy efficiency targets by empowering individual travelers with information needed to make energy-efficient choices and reducing the complexity required to validate transportation system energy savings. This handout provides an overview of NREL's Connected Traveler project, including graphics, milestones, and contact information.

  19. Relative Travel Time Tomography for East Asia

    Science.gov (United States)

    Chang, S. J.; CHO, S.

    2016-12-01

    Japan island region is one of the most seismically active region in the world. As a large number of earthquakes have recently occurred along circum-Pacific belt called the ring of fire, concern over earthquakes is increasing in South Korea close to Japan. In this study, we perform seismic imaging based on relative S-wave travel-times to examine S-wave velocity upper mantle structure of East Asia. We used teleseismic events recorded at the Korea Institute of Geoscience and Mineral Resources (KIGAM) network and F-net network operated by the National Research Institute for Earth Science and Disaster Prevention (NIED). Relative travel-time residuals were obtained by a multi-channel cross-correlation method designed to automatically determine accurate relative phase arrival times. The resulting images show high-velocity anomalies along East and South side of Japan island region. These anomalies may indicate subducting Pacific and Philippine Sea plates, respectively. The velocity structure beneath southwest Japan is revealed very complex because the two slabs interact with each other there. Velocity structure of East Asia is useful to understand the tectonic evolution and the mechanism of earthquakes that occur in this region.

  20. A Data Model for Determining Weather's Impact on Travel Time

    DEFF Research Database (Denmark)

    Andersen, Ove; Torp, Kristian

    2016-01-01

    Accurate estimating travel times in road networks is a complex task because travel times depends on factors such as the weather. In this paper, we present a generic model for integrating weather data with GPS data to improve the accuracy of the estimated travel times. First, we present a data mod...

  1. Macroscopic travel time reliability diagrams for freeway networks

    NARCIS (Netherlands)

    Tu, H.; Li, H.; Van Lint, J.W.C.; Knoop, V.L.; Sun, L.

    2013-01-01

    Travel time reliability is considered to be one of the key indicators of transport system performance. Knowledge of the mechanisms of travel time unreliability enables the derivation of explanatory models with which travel time reliability can be predicted and utilized in traffic management.

  2. Urban travel time reliability at different traffic conditions

    NARCIS (Netherlands)

    Zheng, Fangfang; Li, Jie; van Zuylen, H.J.; Liu, Xiaobo; Yang, Hongtai

    2017-01-01

    The decision making of travelers for route choice and departure time choice depends on the expected travel time and its reliability. A common understanding of reliability is that it is related to several statistical properties of the travel time distribution, especially to the standard deviation

  3. Travel Time Reliability for Urban Networks : Modelling and Empirics

    NARCIS (Netherlands)

    Zheng, F.; Liu, Xiaobo; van Zuylen, H.J.; Li, Jie; Lu, Chao

    2017-01-01

    The importance of travel time reliability in traffic management, control, and network design has received a lot of attention in the past decade. In this paper, a network travel time distribution model based on the Johnson curve system is proposed. The model is applied to field travel time data

  4. Effects of daylight savings time changes on stock market volatility.

    Science.gov (United States)

    Berument, M Hakan; Dogan, Nukhet; Onar, Bahar

    2010-04-01

    The presence of daylight savings time effects on stock returns and on stock volatility was investigated using an EGARCH specification to model the conditional variance. The evidence gathered from the major United States stock markets for the period between 1967 and 2007 did not support the existence of the daylight savings time effect on stock returns or on volatility. Returns on the first business day following daylight savings time changes were not lower nor was the volatility higher, as would be expected if there were an effect.

  5. Contact Frequency, Travel Time, and Travel Costs for Patients with Rheumatoid Arthritis

    Directory of Open Access Journals (Sweden)

    Jan Sørensen

    2014-01-01

    Full Text Available Objectives. To investigate travel time, and travel cost related to contacts with health care providers for patients with rheumatoid arthritis (RA during a three-month period. Methods. Patient-reported travel time and travel cost were obtained from 2847 patients with RA. Eleven outpatient clinics across Denmark recruited patients to the study. Data collected included frequency, travel time and travel costs for contacts at rheumatology outpatient clinics, other outpatient clinics, general practitioners, privately practicing medical specialists, inpatient hospitals and accident and emergency departments. Results. Over a 3-month period, patients with RA had on average 4.4 (sd 5.7 contacts with health care providers, of which 2.8 (sd 4.0 contacts were with rheumatology outpatient clinics. Private car and public travel were the most frequent modes of travel. The average patient spent 63 minutes and 13 € on travelling per contact, corresponding to a total of 4.6 hours and 56 € during the 3-month period. There was great variation in patient travel time and costs, but no statistically significant associations were found with clinical and sociodemographic characteristics. Conclusion. The results show that patients with RA spend private time and costs on travelling when they seek treatment. These findings are particularly important when analyzing social costs associated with RA.

  6. Contact frequency, travel time, and travel costs for patients with rheumatoid arthritis.

    Science.gov (United States)

    Sørensen, Jan; Linde, Louise; Hetland, Merete Lund

    2014-01-01

    Objectives. To investigate travel time, and travel cost related to contacts with health care providers for patients with rheumatoid arthritis (RA) during a three-month period. Methods. Patient-reported travel time and travel cost were obtained from 2847 patients with RA. Eleven outpatient clinics across Denmark recruited patients to the study. Data collected included frequency, travel time and travel costs for contacts at rheumatology outpatient clinics, other outpatient clinics, general practitioners, privately practicing medical specialists, inpatient hospitals and accident and emergency departments. Results. Over a 3-month period, patients with RA had on average 4.4 (sd 5.7) contacts with health care providers, of which 2.8 (sd 4.0) contacts were with rheumatology outpatient clinics. Private car and public travel were the most frequent modes of travel. The average patient spent 63 minutes and 13 € on travelling per contact, corresponding to a total of 4.6 hours and 56 € during the 3-month period. There was great variation in patient travel time and costs, but no statistically significant associations were found with clinical and sociodemographic characteristics. Conclusion. The results show that patients with RA spend private time and costs on travelling when they seek treatment. These findings are particularly important when analyzing social costs associated with RA.

  7. 5 CFR 610.123 - Travel on official time.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Travel on official time. 610.123 Section... DUTY Weekly and Daily Scheduling of Work Work Schedules § 610.123 Travel on official time. Insofar as practicable travel during nonduty hours shall not be required of an employee. When it is essential that this...

  8. Predicting travel time variability for cost-benefit analysis

    NARCIS (Netherlands)

    Peer, S.; Koopmans, C.; Verhoef, E.T.

    2010-01-01

    Unreliable travel times cause substantial costs to travelers. Nevertheless, they are not taken into account in many cost-benefit-analyses (CBA), or only in very rough ways. This paper aims at providing simple rules on how variability can be predicted, based on travel time data from Dutch highways.

  9. Establishing monitoring programs for travel time reliability. [supporting datasets

    Science.gov (United States)

    2014-01-01

    The objective of this project was to develop system designs for programs to monitor travel time reliability and to prepare a guidebook that practitioners and others can use to design, build, operate, and maintain such systems. Generally, such travel ...

  10. Guerrilla Collection Development: Time-Saving Tactics for Busy Librarians.

    Science.gov (United States)

    Quinn, Brian

    1995-01-01

    Reviews time-saving approaches that can help academic librarians (or small libraries lacking collection development librarians) to maintain collections. A sidebar provides information on locating subject publication lists and appendices offer guidelines for collection weeding and sampling. (JMV)

  11. Does extending daylight saving time save energy? Evidence from an Australian experiment

    Energy Technology Data Exchange (ETDEWEB)

    Kellogg, R. [California Univ., Berkeley, CA (United States). Dept. of Agricultural and Resource Economics; Wolff, H. [California Univ., Berkeley, CA (United States). Dept. of Agricultural and Resource Economics]|[Forschungsinstitut zur Zukunft der Arbeit (IZA), Bonn (Germany)

    2007-03-15

    Several countries are considering extending Daylight Saving Time (DST) in order to conserve energy, and the U.S. will extend DST by one month beginning in 2007. However, projections that these extensions will reduce electricity consumption rely on extrapolations and simulations rather than empirical evidence. This paper, in contrast, examines a quasiexperiment in which parts of Australia extended DST in 2000 to facilitate the Sydney Olympics. Using detailed panel data and a triple differences specification, we show that the extension did not conserve electricity, and that a prominent simulation model overstates electricity savings when it is applied to Australia. (orig.)

  12. Year-round daylight saving time will save more energy in India than corresponding DST or time zones

    International Nuclear Information System (INIS)

    Ahuja, Dilip R.; SenGupta, D.P.

    2012-01-01

    Many countries have experimented with daylight saving time (DST) to save energy and to align human activities more closely to the daily cycle of light and darkness. Using a novel methodology, we estimate the year-round energy savings to be obtained from advancing Indian Standard Time (IST), from the introduction of DST, and from dividing the country into two time zones. We find that the option of advancing IST consistently saves more energy than the corresponding DST option, which in turn saves more energy than the corresponding time zones option. This is because the energy benefits of advancing IST accrue for the entire year throughout the country, whereas the benefits of DST are confined to summer months and the benefits of two time zones are largely in the lower energy consuming eastern region. We recommend advancing IST by half-hour to being six hours ahead of UTC. This confers the advantages of DST and time zones without their disadvantages and is forecast to save more than 2 billion kWh of electricity every year during evening peaks that are difficult to supply. While these results are India-specific, similar exercises would be useful to many other countries. - Highlights: ► Advancing IST (YRDST) consistently saves more energy than the corresponding DST. ► DST consistently saves more energy than dividing India into two time zones. ► There are also many non-energy benefits of advancing IST. ► Results are for India; countries with DST may find it useful to consider YRDST.

  13. Saving time with a computerised handbook

    International Nuclear Information System (INIS)

    Henrie, D.K.

    1993-01-01

    The DE/CAASE computerised engineering handbook (Desktop Engineering, Mahwah, NJ, USA) is a software tool designed to automate a wide variety of engineering tasks that are typically performed with an engineering handbook and hand calculator. It significantly reduces the time taken to perform these tasks. For example, instead of spending 60 minutes on determining section properties of composite sections in control room panels and other equipment by hand, it might take less than 5 minutes by using the computerised handbook. Similarly, mode shapes and frequencies of simple structures may take less than 10 minutes to calculate, compared with the hours it used to take. (author)

  14. Time Travel: Separating Science Fact from Science Fiction.

    Science.gov (United States)

    Al-Khalili, Jim

    2003-01-01

    Suggests that the subject of time travel is the best topic to introduce ideas behind some of the most beautiful and fundamental theories about the nature of space and time. Explains the distinction between the two directions of time travel and how relativity theory forced the abandonment of Newtonian notions about the nature of time. (Author/KHR)

  15. Quantifying travel time variability in transportation networks.

    Science.gov (United States)

    2010-03-01

    Nonrecurring congestion creates significant delay on freeways in urban areas, lending importance : to the study of facility reliability. In locations where traffic detectors record and archive data, : approximate probability distributions for travel ...

  16. Multiple-Factor Based Sparse Urban Travel Time Prediction

    Directory of Open Access Journals (Sweden)

    Xinyan Zhu

    2018-02-01

    Full Text Available The prediction of travel time is challenging given the sparseness of real-time traffic data and the uncertainty of travel, because it is influenced by multiple factors on the congested urban road networks. In our paper, we propose a three-layer neural network from big probe vehicles data incorporating multi-factors to estimate travel time. The procedure includes the following three steps. First, we aggregate data according to the travel time of a single taxi traveling a target link on working days as traffic flows display similar traffic patterns over a weekly cycle. We then extract feature relationships between target and adjacent links at 30 min interval. About 224,830,178 records are extracted from probe vehicles. Second, we design a three-layer artificial neural network model. The number of neurons in input layer is eight, and the number of neurons in output layer is one. Finally, the trained neural network model is used for link travel time prediction. Different factors are included to examine their influence on the link travel time. Our model is verified using historical data from probe vehicles collected from May to July 2014 in Wuhan, China. The results show that we could obtain the link travel time prediction results using the designed artificial neural network model and detect the influence of different factors on link travel time.

  17. Contact frequency, travel time, and travel costs for patients with rheumatoid arthritis

    DEFF Research Database (Denmark)

    Sørensen, Jan; Linde, Louise; Hetland, Merete Lund

    2014-01-01

    across Denmark recruited patients to the study. Data collected included frequency, travel time and travel costs for contacts at rheumatology outpatient clinics, other outpatient clinics, general practitioners, privately practicing medical specialists, inpatient hospitals and accident and emergency...... departments. Results. Over a 3-month period, patients with RA had on average 4.4 (sd 5.7) contacts with health care providers, of which 2.8 (sd 4.0) contacts were with rheumatology outpatient clinics. Private car and public travel were the most frequent modes of travel. The average patient spent 63 minutes...

  18. Daylight Saving Time Transitions and Road Traffic Accidents

    Directory of Open Access Journals (Sweden)

    Tuuli Lahti

    2010-01-01

    Full Text Available Circadian rhythm disruptions may have harmful impacts on health. Circadian rhythm disruptions caused by jet lag compromise the quality and amount of sleep and may lead to a variety of symptoms such as fatigue, headache, and loss of attention and alertness. Even a minor change in time schedule may cause considerable stress for the body. Transitions into and out of daylight saving time alter the social and environmental timing twice a year. According to earlier studies, this change in time-schedule leads to sleep disruption and fragmentation of the circadian rhythm. Since sleep deprivation decreases motivation, attention, and alertness, transitions into and out of daylight saving time may increase the amount of accidents during the following days after the transition. We studied the amount of road traffic accidents one week before and one week after transitions into and out of daylight saving time during years from 1981 to 2006. Our results demonstrated that transitions into and out of daylight saving time did not increase the number of traffic road accidents.

  19. Online Learning Solutions for Freeway Travel Time Prediction

    NARCIS (Netherlands)

    Van Lint, J.W.C.

    2008-01-01

    Providing travel time information to travelers on available route alternatives in traffic networks is widely believed to yield positive effects on individual drive behavior and (route/departure time) choice behavior, as well as on collective traffic operations in terms of, for example, overall time

  20. Estimating travel times using Wi-Fi sensor data

    NARCIS (Netherlands)

    Hoogendoorn, S.P.; Daamen, W.; Duives, D.C.; Yuan, Y.

    2016-01-01

    Determining travel time information from Wi-Fi (or Bluetooth) sensors is not trivial due to various (often technical) reasons. In this contribution, we focus on the problem of distinguishing travel time from the time people spend performing activities (e.g. fuelling the car, standing still to watch

  1. Variability of Travel Times on New Jersey Highways

    Science.gov (United States)

    2011-06-01

    This report presents the results of a link and path travel time study conducted on selected New Jersey (NJ) highways to produce estimates of the corresponding variability of travel time (VTT) by departure time of the day and days of the week. The tra...

  2. Effectiveness of different approaches to disseminating traveler information on travel time reliability.

    Science.gov (United States)

    2014-01-01

    The second Strategic Highway Research Program (SHRP 2) Reliability program aims to improve trip time reliability by reducing the frequency and effects of events that cause travel times to fluctuate unpredictably. Congestion caused by unreliable, or n...

  3. The Role of Perspective in Mental Time Travel

    Directory of Open Access Journals (Sweden)

    Caterina Ansuini

    2016-01-01

    Full Text Available Recent years have seen accumulating evidence for the proposition that people process time by mapping it onto a linear spatial representation and automatically “project” themselves on an imagined mental time line. Here, we ask whether people can adopt the temporal perspective of another person when travelling through time. To elucidate similarities and differences between time travelling from one’s own perspective or from the perspective of another person, we asked participants to mentally project themselves or someone else (i.e., a coexperimenter to different time points. Three basic properties of mental time travel were manipulated: temporal location (i.e., where in time the travel originates: past, present, and future, motion direction (either backwards or forwards, and temporal duration (i.e., the distance to travel: one, three, or five years. We found that time travels originating in the present lasted longer in the self- than in the other-perspective. Moreover, for self-perspective, but not for other-perspective, time was differently scaled depending on where in time the travel originated. In contrast, when considering the direction and the duration of time travelling, no dissimilarities between the self- and the other-perspective emerged. These results suggest that self- and other-projection, despite some differences, share important similarities in structure.

  4. Critical capacity, travel time delays and travel time distribution of rapid mass transit systems

    Science.gov (United States)

    Legara, Erika Fille; Monterola, Christopher; Lee, Kee Khoon; Hung, Gih Guang

    2014-07-01

    We set up a mechanistic agent-based model of a rapid mass transit system. Using empirical data from Singapore's unidentifiable smart fare card, we validate our model by reconstructing actual travel demand and duration of travel statistics. We subsequently use this model to investigate two phenomena that are known to significantly affect the dynamics within the RTS: (1) overloading in trains and (2) overcrowding in the RTS platform. We demonstrate that by varying the loading capacity of trains, a tipping point emerges at which an exponential increase in the duration of travel time delays is observed. We also probe the impact on the rail system dynamics of three types of passenger growth distribution across stations: (i) Dirac delta, (ii) uniform and (iii) geometric, which is reminiscent of the effect of land use on transport. Under the assumption of a fixed loading capacity, we demonstrate the dependence of a given origin-destination (OD) pair on the flow volume of commuters in station platforms.

  5. The Optimization of Passengers’ Travel Time under Express-Slow Mode Based on Suburban Line

    Directory of Open Access Journals (Sweden)

    Xiaobing Ding

    2016-01-01

    Full Text Available The suburban line connects the suburbs and the city centre; it is of huge advantage to attempt the express-slow mode. The passengers’ average travel time is the key factor to reflect the level of rail transport services, especially under the express-slow mode. So it is important to study the passengers’ average travel time under express-slow, which can get benefit on the optimization of operation scheme. First analyze the main factor that affects passengers’ travel time and then mine the dynamic interactive relationship among the factors. Second, a new passengers’ travel time evolution algorithm is proposed after studying the stop schedule and the proportion of express/slow train, and then membrane computing theory algorithm is introduced to solve the model. Finally, Shanghai Metro Line 22 is set as an example to apply the optimization model to calculate the total passengers’ travel time; the result shows that the total average travel time under the express-slow mode can save 1 minute and 38 seconds; the social influence and value of it are very huge. The proposed calculation model is of great help for the decision of stop schedule and provides theoretical and methodological support to determine the proportion of express/slow trains, improves the service level, and enriches and complements the rail transit operation scheme optimization theory system.

  6. Backus-Gilbert inversion of travel time data

    Science.gov (United States)

    Johnson, L. E.

    1972-01-01

    Application of the Backus-Gilbert theory for geophysical inverse problems to the seismic body wave travel-time problem is described. In particular, it is shown how to generate earth models that fit travel-time data to within one standard error and having generated such models how to describe their degree of uniqueness. An example is given to illustrate the process.

  7. Collection and analysis of 2013-2014 travel time data.

    Science.gov (United States)

    2017-07-04

    This report documents the findings of Planning Study 27, Collection and Analysis of 2013-2014 Travel Time Data, which is a continuation of Planning Study 24, Analysis of Historical Travel Time Data. The main scope is to analyze newly acquired link-re...

  8. Green Routing Fuel Saving Opportunity Assessment: A Case Study on California Large-Scale Real-World Travel Data

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Lei [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Holden, Jacob [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Gonder, Jeffrey D [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wood, Eric W [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-07-31

    New technologies, such as connected and automated vehicles, have attracted more and more researchers for improving the energy efficiency and environmental impact of current transportation systems. The green routing strategy instructs a vehicle to select the most fuel-efficient route before the vehicle departs. It benefits the current transportation system with fuel saving opportunity through identifying the greenest route. This paper introduces an evaluation framework for estimating benefits of green routing based on large-scale, real-world travel data. The framework has the capability to quantify fuel savings by estimating the fuel consumption of actual routes and comparing to routes procured by navigation systems. A route-based fuel consumption estimation model, considering road traffic conditions, functional class, and road grade is proposed and used in the framework. An experiment using a large-scale data set from the California Household Travel Survey global positioning system trajectory data base indicates that 31% of actual routes have fuel savings potential with a cumulative estimated fuel savings of 12%.

  9. Green Routing Fuel Saving Opportunity Assessment: A Case Study on California Large-Scale Real-World Travel Data: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Lei; Holden, Jacob; Gonder, Jeff; Wood, Eric

    2017-07-13

    New technologies, such as connected and automated vehicles, have attracted more and more researchers for improving the energy efficiency and environmental impact of current transportation systems. The green routing strategy instructs a vehicle to select the most fuel-efficient route before the vehicle departs. It benefits the current transportation system with fuel saving opportunity through identifying the greenest route. This paper introduces an evaluation framework for estimating benefits of green routing based on large-scale, real-world travel data. The framework has the capability to quantify fuel savings by estimating the fuel consumption of actual routes and comparing to routes procured by navigation systems. A route-based fuel consumption estimation model, considering road traffic conditions, functional class, and road grade is proposed and used in the framework. An experiment using a large-scale data set from the California Household Travel Survey global positioning system trajectory data base indicates that 31% of actual routes have fuel savings potential with a cumulative estimated fuel savings of 12%.

  10. Mode choice endogeneity in value of travel time estimation

    DEFF Research Database (Denmark)

    Mabit, Stefan Lindhard; Fosgerau, Mogens

    The current way to estimate value of travel time is to use a mode-specific sample and hence to estimate mode-specific value of travel times. This approach raises certain questions concerning how to generalise the values to a population. A problem would be if there is an uncontrolled sample...... selection mechanism. This is the case if there is correlation between mode choice and the value of travel time that is not controlled for by explanatory variables. What could confuse the estimated values is the difficulty to separate mode effects from user effect. An example would be the effect of income...... of travel time we use a stated choice dataset. These data include binary choice within mode for car and bus. The first approach is to use a probit model to model mode choice using instruments and then use this in the estimation of the value of travel time. The second approach is based on the use of a very...

  11. Wandering tales: evolutionary origins of mental time travel and language

    Science.gov (United States)

    Corballis, Michael C.

    2013-01-01

    A central component of mind wandering is mental time travel, the calling to mind of remembered past events and of imagined future ones. Mental time travel may also be critical to the evolution of language, which enables us to communicate about the non-present, sharing memories, plans, and ideas. Mental time travel is indexed in humans by hippocampal activity, and studies also suggest that the hippocampus in rats is active when the animals replay or pre play activity in a spatial environment, such as a maze. Mental time travel may have ancient origins, contrary to the view that it is unique to humans. Since mental time travel is also thought to underlie language, these findings suggest that language evolved gradually from pre-existing cognitive capacities, contrary to the view of Chomsky and others that language and symbolic thought emerged abruptly, in a single step, within the past 100,000 years. PMID:23908641

  12. Wandering Tales: Evolutionary origins of mental time travel and language

    Directory of Open Access Journals (Sweden)

    Michael Charles Corballis

    2013-07-01

    Full Text Available A central component of mind wandering is mental time travel, the calling to mind of remembered past events and of imagined future ones. Mental time travel may also be critical to the evolution of language, which enables us to communicate about the nonpresent, sharing memories, plans, and ideas. Mental time travel is indexed in humans by hippocampal activity, and studies also suggest that the hippocampus in rats is active when the animals replay or pre play activity in a spatial environment, such as a maze. Mental time travel may have ancient origins, contrary to the view that it is unique to humans. Since mental time travel is also thought to underlie language, these findings suggest that language evolved gradually from pre-existing cognitive capacities, contrary to the view of Chomsky and others that language and symbolic thought emerged abruptly, in a single step, within the past 100,000 years.

  13. Travel time data collection for measurement of advanced traveler information systems accuracy

    Science.gov (United States)

    2003-06-01

    The objective of this white paper is to recommend an approach to measuring ATIS travel time accuracy so that ITS planners might have the data they need to make cost effective decisions regarding deployment of surveillance technologies to support ATIS...

  14. Modeling, implementation, and validation of arterial travel time reliability : [summary].

    Science.gov (United States)

    2013-11-01

    Travel time reliability (TTR) has been proposed as : a better measure of a facilitys performance than : a statistical measure like peak hour demand. TTR : is based on more information about average traffic : flows and longer time periods, thus inc...

  15. How travellers’ schedule their trips under uncertain travel times

    DEFF Research Database (Denmark)

    Hjorth, Katrine

    Travel times play an important role when people decide where, when and how much to travel. But travel times are not always predictable from the traveller’s point of view: They may vary from day to day due to demand fluctuations, weather conditions, accidents and other unforeseen events that cause...... road capacity to decrease. We refer to this uncertainty as travel time variability (TTV). TTV is likely to affect how travellers schedule their trips, since it affects their probability of arriving late at their destination. We would like to account for TTV in traffic models and cost-benefit analyses......, but in practice there are limits to the kinds of behaviour that can be accommodated in such applications. For that reason, we are not solely interested in explaining travellers’ behaviour, but also in whether this behaviour can be approximated by behavioural models that are simple enough to be applied in traffic...

  16. A Dynamic Travel Time Estimation Model Based on Connected Vehicles

    Directory of Open Access Journals (Sweden)

    Daxin Tian

    2015-01-01

    Full Text Available With advances in connected vehicle technology, dynamic vehicle route guidance models gradually become indispensable equipment for drivers. Traditional route guidance models are designed to direct a vehicle along the shortest path from the origin to the destination without considering the dynamic traffic information. In this paper a dynamic travel time estimation model is presented which can collect and distribute traffic data based on the connected vehicles. To estimate the real-time travel time more accurately, a road link dynamic dividing algorithm is proposed. The efficiency of the model is confirmed by simulations, and the experiment results prove the effectiveness of the travel time estimation method.

  17. Wireless data collection system for real-time arterial travel time estimates.

    Science.gov (United States)

    2011-03-01

    This project pursued several objectives conducive to the implementation and testing of a Bluetooth (BT) based system to collect travel time data, including the deployment of a BT-based travel time data collection system to perform comprehensive testi...

  18. Influence of queue propagation and dissipation on route travel times

    DEFF Research Database (Denmark)

    Raovic, Nevena

    into account (Bliemer, 2008). Yperman (2007) indicates that there is a significant difference in queue-propagation and queue-dissipation between the LTM and DQM. This results in different route travel times, and can further affect route choice. In this paper, different approaches to represent queue propagation...... and dissipation through the CTM, LTM and DQM are studied. A simple network allows to show how these approaches influence route travel time. Furthermore, the possibility of changing the existing DQM is considered in order to more realistically represent queue propagation and dissipation, which would lead to more...... accurate route travel times....

  19. Accuracy of Travel Time Estimation using Bluetooth Technology

    DEFF Research Database (Denmark)

    Araghi, Bahar Namaki; Skoven Pedersen, Kristian; Tørholm Christensen, Lars

    2012-01-01

    Short-term travel time information plays a critical role in Advanced Traffic Information Systems (ATIS) and Advanced Traffic Management Systems (ATMS). In this context, the need for accurate and reliable travel time information sources is becoming increasingly important. Bluetooth Technology (BT...... to quantify the accuracy and robustness of these estimators against outliers, a comparative study between BT and Floating Car Data (FCD) is conducted. Results show that the Min-BT and Med-BT are more robust concerning the existence of outliers in the dataset and can provide more accurate travel time estimates...

  20. Save Time with a High-Performance Grading System

    Science.gov (United States)

    Slater, Timothy F.

    2005-09-01

    Tim Slater is an associate professor of astronomy at the University of Arizona, where he directs the Science and Mathematics Education Center and conducts research on teaching and learning of Earth and space science. Tim's contributions to this column have proven valuable for physics teachers at both high school and university levels. Here he shares some time-saving tips that will help the busy teacher give students valuable feedback.

  1. Phase Behavior and Implications for Travel time Observables (PHASE 2)

    Science.gov (United States)

    2015-09-30

    perturbation behavior of travel time observables due to sound-speed perturbations . OBJECTIVES The objective is to study the behavior of the wave-theoretic...the corresponding travel-time observables ( ) ( ) V K z c z dz   (12) The similarities and dissimilarities in the perturbation behaviour...turn out to be successful for all three observables . The demodulated phase arrival times appear to be more affected by the sound-speed perturbations

  2. Assessing the Predictability of Scheduled-Vehicle Travel Times

    DEFF Research Database (Denmark)

    Tiesyte, Dalia; Jensen, Christian Søndergaard

    2009-01-01

    One of the most desired and challenging services in collective transport systems is the real-time prediction of the near-future travel times of scheduled vehicles, especially public buses, thus improving the experience of the transportation users, who may be able to better schedule their travel......, and also enabling system operators to perform real-time monitoring. While travel-time prediction has been researched extensively during the past decade, the accuracies of existing techniques fall short of what is desired, and proposed mathematical prediction models are often not transferable to other...... systems because the properties of the travel-time-related data of vehicles are highly context-dependent, making the models difficult to fit. We propose a framework for evaluating various predictability types of the data independently of the model, and we also compare predictability analysis results...

  3. Quantum mechanics of time travel through post-selected teleportation

    International Nuclear Information System (INIS)

    Lloyd, Seth; Garcia-Patron, Raul; Maccone, Lorenzo; Giovannetti, Vittorio; Shikano, Yutaka

    2011-01-01

    This paper discusses the quantum mechanics of closed-timelike curves (CTCs) and of other potential methods for time travel. We analyze a specific proposal for such quantum time travel, the quantum description of CTCs based on post-selected teleportation (P-CTCs). We compare the theory of P-CTCs to previously proposed quantum theories of time travel: the theory is inequivalent to Deutsch's theory of CTCs, but it is consistent with path-integral approaches (which are the best suited for analyzing quantum-field theory in curved space-time). We derive the dynamical equations that a chronology-respecting system interacting with a CTC will experience. We discuss the possibility of time travel in the absence of general-relativistic closed-timelike curves, and investigate the implications of P-CTCs for enhancing the power of computation.

  4. Impact of data source on travel time reliability assessment.

    Science.gov (United States)

    2014-08-01

    Travel time reliability measures are becoming an increasingly important input to the mobility and : congestion management studies. In the case of Maryland State Highway Administration, reliability : measures are key elements in the agencys Annual ...

  5. Bluetooth-based travel time/speed measuring systems development.

    Science.gov (United States)

    2010-06-01

    Agencies in the Houston region have traditionally used toll tag readers to provide travel times on : freeways and High Occupancy Vehicle (HOV) lanes, but these systems require large amounts of costly and : physically invasive infrastructure. Bluetoot...

  6. Estimating spatial travel times using automatic vehicle identification data

    Science.gov (United States)

    2001-01-01

    Prepared ca. 2001. The paper describes an algorithm that was developed for estimating reliable and accurate average roadway link travel times using Automatic Vehicle Identification (AVI) data. The algorithm presented is unique in two aspects. First, ...

  7. Modeling, implementation, and validation of arterial travel time reliability.

    Science.gov (United States)

    2013-11-01

    Previous research funded by Florida Department of Transportation (FDOT) developed a method for estimating : travel time reliability for arterials. This method was not initially implemented or validated using field data. This : project evaluated and r...

  8. Application of travel time information for traffic management.

    Science.gov (United States)

    2012-03-01

    This report summarizes findings and implementations of probe vehicle data collection based on Bluetooth MAC address matching : technology. Probe vehicle travel time data are studied in the following field deployment case studies: analysis of traffic ...

  9. Measurement and evaluation of transit travel time reliability

    Science.gov (United States)

    2011-01-01

    Transportation system customers need consistency in their daily travel times to enable them to plan their daily : activities, whether that is a commuter on their way to work, a company setting up delivery schedules for justintime : manufacturin...

  10. Time Travelling with Jack the Ripper on Page and Screen

    OpenAIRE

    Lucyna Krawczyk-Żywko

    2017-01-01

    The article discusses time-travelling Jack the Ripper narratives, the majority being short stories and episodes of TV series. Despite their different temporal foci – late-Victorian past, present, distant future – the texts revolve around four ways of depicting the mysterious murderer: as a timeless force, a killer who uses time travel to escape, a killer whose deeds are to be prevented, and, last but not least, a tool in the hands of future generations. They also indicate that ...

  11. Innovative methods for calculation of freeway travel time using limited data : executive summary report.

    Science.gov (United States)

    2008-08-01

    ODOTs policy for Dynamic Message Sign : utilization requires travel time(s) to be displayed as : a default message. The current method of : calculating travel time involves a workstation : operator estimating the travel time based upon : observati...

  12. Bayesian Nonparametric Model for Estimating Multistate Travel Time Distribution

    Directory of Open Access Journals (Sweden)

    Emmanuel Kidando

    2017-01-01

    Full Text Available Multistate models, that is, models with more than two distributions, are preferred over single-state probability models in modeling the distribution of travel time. Literature review indicated that the finite multistate modeling of travel time using lognormal distribution is superior to other probability functions. In this study, we extend the finite multistate lognormal model of estimating the travel time distribution to unbounded lognormal distribution. In particular, a nonparametric Dirichlet Process Mixture Model (DPMM with stick-breaking process representation was used. The strength of the DPMM is that it can choose the number of components dynamically as part of the algorithm during parameter estimation. To reduce computational complexity, the modeling process was limited to a maximum of six components. Then, the Markov Chain Monte Carlo (MCMC sampling technique was employed to estimate the parameters’ posterior distribution. Speed data from nine links of a freeway corridor, aggregated on a 5-minute basis, were used to calculate the corridor travel time. The results demonstrated that this model offers significant flexibility in modeling to account for complex mixture distributions of the travel time without specifying the number of components. The DPMM modeling further revealed that freeway travel time is characterized by multistate or single-state models depending on the inclusion of onset and offset of congestion periods.

  13. Back or to the future? Preferences of time travelers

    Directory of Open Access Journals (Sweden)

    Ralph Hertwig

    2012-07-01

    Full Text Available Popular culture reflects whatever piques our imagination. Think of the myriad movies and books that take viewers and readers on an imaginary journey to the past or the future (e.g., Gladiator, The Time Machine. Despite the ubiquity of time travel as a theme in cultural expression, the factors that underlie people's preferences concerning the direction of time travel have gone unexplored. What determines whether a person would prefer to visit the (certain past or explore the (uncertain future? We identified three factors that markedly affect people's preference for (hypothetical travel to the past or the future, respectively. Those who think of themselves as courageous, those with a more conservative worldview, and---perhaps counterintuitively---those who are advanced in age prefer to travel into the future. We discuss implications of these initial results.

  14. Validation and augmentation of Inrix arterial travel time data using independent sources : [research summary].

    Science.gov (United States)

    2015-02-01

    Although the freeway travel time data has been validated extensively in recent : years, the quality of arterial travel time data is not well known. This project : presents a comprehensive validation scheme for arterial travel time data based : on GPS...

  15. Modeling highway travel time distribution with conditional probability models

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira Neto, Francisco Moraes [ORNL; Chin, Shih-Miao [ORNL; Hwang, Ho-Ling [ORNL; Han, Lee [University of Tennessee, Knoxville (UTK)

    2014-01-01

    ABSTRACT Under the sponsorship of the Federal Highway Administration's Office of Freight Management and Operations, the American Transportation Research Institute (ATRI) has developed performance measures through the Freight Performance Measures (FPM) initiative. Under this program, travel speed information is derived from data collected using wireless based global positioning systems. These telemetric data systems are subscribed and used by trucking industry as an operations management tool. More than one telemetric operator submits their data dumps to ATRI on a regular basis. Each data transmission contains truck location, its travel time, and a clock time/date stamp. Data from the FPM program provides a unique opportunity for studying the upstream-downstream speed distributions at different locations, as well as different time of the day and day of the week. This research is focused on the stochastic nature of successive link travel speed data on the continental United States Interstates network. Specifically, a method to estimate route probability distributions of travel time is proposed. This method uses the concepts of convolution of probability distributions and bivariate, link-to-link, conditional probability to estimate the expected distributions for the route travel time. Major contribution of this study is the consideration of speed correlation between upstream and downstream contiguous Interstate segments through conditional probability. The established conditional probability distributions, between successive segments, can be used to provide travel time reliability measures. This study also suggests an adaptive method for calculating and updating route travel time distribution as new data or information is added. This methodology can be useful to estimate performance measures as required by the recent Moving Ahead for Progress in the 21st Century Act (MAP 21).

  16. The meandering mind: vection and mental time travel.

    Directory of Open Access Journals (Sweden)

    Lynden K Miles

    Full Text Available BACKGROUND: The ability to travel mentally through time sets humans apart from many other species, yet little is known about this core cognitive capacity. In particular, what shapes the passage of the mind's journey through time? Guided by the viewpoint that higher cognitive activity can have a sensory-motor grounding, we explored the possibility that mental time travel is influenced by apparent movement through space. METHODOLOGY/PRINCIPAL FINDINGS: Participants performed a mundane vigilance task, during which they were expected to daydream, while viewing a display that elicited an illusion of self-motion (i.e., vection. Afterwards, the contents of their mind wandering experiences were probed. The results revealed that the direction of apparent motion influenced the temporal focus of mental time travel. While backward vection prompted thinking about the past, forward vection triggered a preponderance of future-oriented thoughts. CONCLUSIONS/SIGNIFICANCE: Consistent with recent evidence that traveling mentally through time entails associated movements in space, the current results demonstrate the converse relationship-apparent movement through space influenced the temporal locus of mental activity. Together, these findings corroborate the viewpoint that mental time travel may be grounded in the embodiment of spatiotemporal information in a bidirectional manner.

  17. Prisms to travel in time: Investigation of time-space association through prismatic adaptation effect on mental time travel.

    Science.gov (United States)

    Anelli, Filomena; Ciaramelli, Elisa; Arzy, Shahar; Frassinetti, Francesca

    2016-11-01

    Accumulating evidence suggests that humans process time and space in similar veins. Humans represent time along a spatial continuum, and perception of temporal durations can be altered through manipulations of spatial attention by prismatic adaptation (PA). Here, we investigated whether PA-induced manipulations of spatial attention can also influence more conceptual aspects of time, such as humans' ability to travel mentally back and forward in time (mental time travel, MTT). Before and after leftward- and rightward-PA, participants projected themselves in the past, present or future time (i.e., self-projection), and, for each condition, determined whether a series of events were located in the past or the future with respect to that specific self-location in time (i.e., self-reference). The results demonstrated that leftward and rightward shifts of spatial attention facilitated recognition of past and future events, respectively. These findings suggest that spatial attention affects the temporal processing of the human self. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Measurement of time of travel in streams by dye tracing

    Science.gov (United States)

    Kilpatrick, F.A.; Wilson, James F.

    1989-01-01

    The use of fluorescent dyes and tracing techniques provides a means for measuring the time-of-travel and dispersion characteristics of steady and gradually varied flow in streams. Measurements of the dispersion and concentration of dyes give insight into the behavior of soluble contaminants that may be introduced into a stream. This manual describes methods of measuring time of travel of water and waterborne solutes by dye tracing. The fluorescent dyes, measuring equipment used, and the field and laboratory procedures are also described. Methods of analysis and presentation to illustrate time-oftravel and dispersion characteristics of streams are provided.

  19. 41 CFR 301-52.14 - What must I do with any travel advance outstanding at the time I submit my travel claim?

    Science.gov (United States)

    2010-07-01

    ... travel advance outstanding at the time I submit my travel claim? 301-52.14 Section 301-52.14 Public Contracts and Property Management Federal Travel Regulation System TEMPORARY DUTY (TDY) TRAVEL ALLOWANCES... § 301-52.14 What must I do with any travel advance outstanding at the time I submit my travel claim? You...

  20. Travel the Globe: Multicultural Story Times.

    Science.gov (United States)

    Webber, Desiree; Corn, Dee Ann; Harrod, Elaine; Norvell, Donna; Shropshire, Sandy

    Designed for Grades PreK-3, the culture-based story times and extension activities provided in this book give educators the opportunity to share the diversity of global neighbors with young learners. The book covers Australia, Brazil, the Caribbean, China, Egypt, Ghana, Greece, India, Ireland, Italy, Mexico, the Commonwealth of Independent States…

  1. Freight Transport Time Savings and Organizational Performance: A Systemic Approach

    Directory of Open Access Journals (Sweden)

    Evangelos Sambracos

    2013-04-01

    Full Text Available This paper investigates the effect of freight transport time savings (FTTS on the performance of transport consuming companies. In the first part existing methods on FTTS valuation are critically discussed and their limitations are identified. Following, a conceptual model is built introducing an alternative approach for the valuation of FTTS that is based on the system perspective of firms, integrating the disciplines of systems thinking, performance measurement, transport and logistics decision making. Evidence from a Systems Dynamics’ simulation experiment on a retailer suggests that the effect of FTTS on performance depends highly on the structure of the firm's transport related processes and decision making process. Through the development and simulation of several scenarios concerning the reaction of the firm to the FTTS, it is concluded that the value of FTTS is sensitive to the type of the reaction and its time profile.

  2. Splitting Travel Time Based on AFC Data: Estimating Walking, Waiting, Transfer, and In-Vehicle Travel Times in Metro System

    Directory of Open Access Journals (Sweden)

    Yong-Sheng Zhang

    2015-01-01

    Full Text Available The walking, waiting, transfer, and delayed in-vehicle travel times mainly contribute to route’s travel time reliability in the metro system. The automatic fare collection (AFC system provides huge amounts of smart card records which can be used to estimate all these times distributions. A new estimation model based on Bayesian inference formulation is proposed in this paper by integrating the probability measurement of the OD pair with only one effective route, in which all kinds of times follow the truncated normal distributions. Then, Markov Chain Monte Carlo method is designed to estimate all parameters endogenously. Finally, based on AFC data in Guangzhou Metro, the estimations show that all parameters can be estimated endogenously and identifiably. Meanwhile, the truncated property of the travel time is significant and the threshold tested by the surveyed data is reliable. Furthermore, the superiority of the proposed model over the existing model in estimation and forecasting accuracy is also demonstrated.

  3. Extremal inversion of lunar travel time data. [seismic velocity structure

    Science.gov (United States)

    Burkhard, N.; Jackson, D. D.

    1975-01-01

    The tau method, developed by Bessonova et al. (1974), of inversion of travel times is applied to lunar P-wave travel time data to find limits on the velocity structure of the moon. Tau is the singular solution to the Clairaut equation. Models with low-velocity zones, with low-velocity zones at differing depths, and without low-velocity zones, were found to be consistent with data and within the determined limits. Models with and without a discontinuity at about 25-km depth have been found which agree with all travel time data to within two standard deviations. In other words, the existence of the discontinuity and its size and location have not been uniquely resolved. Models with low-velocity channels are also possible.

  4. Reliability of Bluetooth Technology for Travel Time Estimation

    DEFF Research Database (Denmark)

    Araghi, Bahar Namaki; Olesen, Jonas Hammershøj; Krishnan, Rajesh

    2015-01-01

    to calculate actual travel time, referred to as ground truth, and to geo-code the Bluetooth detection events. In this setting, reliability is defined as the percentage of devices captured per trip during the experiment. It is found that, on average, Bluetooth-enabled devices will be detected 80% of the time...

  5. Travelling wave solutions of (2 1)-dimensional generalised time ...

    Indian Academy of Sciences (India)

    Youwei Zhang

    2018-02-09

    Feb 9, 2018 ... Keywords. Time-fractional Hirota equation; fractional complex transform; complete discrimination system; tanh- expansion; travelling wave. PACS Nos 02.30.Jr; 05.45.Yv; 04.20.Jb. 1. Introduction. We consider the solution of the (2 + 1)-dimensional generalised time-fractional Hirota equation. { i∂ α t u + uxy ...

  6. The A-priori Traveling Salesman Problem with Time Windows

    DEFF Research Database (Denmark)

    Larsen, Allan; Madsen, Oli B.G.; Solomon, Marius M.

    2004-01-01

    In this paper we examine the traveling saleman problem with time windows for various degrees of dynamism. In contrast to the static problem, where the dispatcher can plan ahead, in the dynamic version, part or all of the necessary information becomes available only during the day of operation. We...... seek to minimize lateness and examine the impact of this criterion choice on the distance traveled. Our focus on lateness is motivated by the problem faced by overnight mail service providers. We propose a real-time solution method that requires the vehicle, when idle, to wait at the current customer...

  7. Visualizations of Travel Time Performance Based on Vehicle Reidentification Data

    Energy Technology Data Exchange (ETDEWEB)

    Young, Stanley Ernest [National Renewable Energy Lab, 15013 Denver West Parkway, Golden, CO 80401; Sharifi, Elham [Center for Advanced Transportation Technology, University of Maryland, College Park, Technology Ventures Building, Suite 2200, 5000 College Avenue, College Park, MD 20742; Day, Christopher M. [Joint Transportation Research Program, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47906; Bullock, Darcy M. [Lyles School of Civil Engineering, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47906

    2017-01-01

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

  8. Breast cancer stage at diagnosis: is travel time important?

    Science.gov (United States)

    Henry, Kevin A; Boscoe, Francis P; Johnson, Christopher J; Goldberg, Daniel W; Sherman, Recinda; Cockburn, Myles

    2011-12-01

    Recent studies have produced inconsistent results in their examination of the potential association between proximity to healthcare or mammography facilities and breast cancer stage at diagnosis. Using a multistate dataset, we re-examine this issue by investigating whether travel time to a patient's diagnosing facility or nearest mammography facility impacts breast cancer stage at diagnosis. We studied 161,619 women 40 years and older diagnosed with invasive breast cancer from ten state population based cancer registries in the United States. For each woman, we calculated travel time to their diagnosing facility and nearest mammography facility. Logistic multilevel models of late versus early stage were fitted, and odds ratios were calculated for travel times, controlling for age, race/ethnicity, census tract poverty, rural/urban residence, health insurance, and state random effects. Seventy-six percent of women in the study lived less than 20 min from their diagnosing facility, and 93 percent lived less than 20 min from the nearest mammography facility. Late stage at diagnosis was not associated with increasing travel time to diagnosing facility or nearest mammography facility. Diagnosis age under 50, Hispanic and Non-Hispanic Black race/ethnicity, high census tract poverty, and no health insurance were all significantly associated with late stage at diagnosis. Travel time to diagnosing facility or nearest mammography facility was not a determinant of late stage of breast cancer at diagnosis, and better geographic proximity did not assure more favorable stage distributions. Other factors beyond geographic proximity that can affect access should be evaluated more closely, including facility capacity, insurance acceptance, public transportation, and travel costs.

  9. Green Driver: Travel Behaviors Revisited on Fuel Saving and Less Emission

    Directory of Open Access Journals (Sweden)

    Nurul Hidayah Muslim

    2018-01-01

    Full Text Available Road transportation is the main energy consumer and major contributor of ever-increasing hazardous emissions. Transportation professionals have raised the idea of applying the green concept in various areas of transportation, including green highways, green vehicles and transit-oriented designs, to tackle the negative impact of road transportation. This research generated a new dimension called the green driver to remediate urgently the existing driving assessment models that have intensified emissions and energy consumption. In this regard, this study aimed to establish the green driver’s behaviors related to fuel saving and emission reduction. The study has two phases. Phase one involves investigating the driving behaviors influencing fuel saving and emission reduction through a systematic literature review and content analysis, which identified twenty-one variables classified into four clusters. These clusters included the following: (i FEf1, which is driving style; (ii FEf2, which is driving behavior associated with vehicle transmission; (iii FEf3, which is driving behavior associated with road design and traffic rules; and (iv FEf4, which is driving behavior associated with vehicle operational characteristics. The second phase involves validating phase one findings by applying the Grounded Group Decision Making (GGDM method. The results of GGDM have established seventeen green driving behaviors. The study conducted the Green Value (GV analysis for each green behavior on fuel saving and emission reduction. The study found that aggressive driving (GV = 0.16 interferes with the association between fuel consumption, emission and driver’s personalities. The research concludes that driver’s personalities (including physical, psychological and psychosocial characteristics have to be integrated for advanced in-vehicle driver assistance system and particularly, for green driving accreditation.

  10. Reducing employee travelling time through smart commuting

    International Nuclear Information System (INIS)

    Rahman, A N N A; Yusoff, Z M; Aziz, I S; Omar, D

    2014-01-01

    Extremely congested roads will definitely delay the arrival time of each trip.This certainly impacted the journey of employees. Tardiness at the workplace has become a perturbing issue for companies where traffic jams are the most common worker excuses. A depressing consequence on daily life and productivity of the employee occurs. The issues of commuting distance between workplace and resident area become the core point of this research. This research will emphasize the use of Geographical Information System (GIS) technique to explore the distance parameter to the employment area and will focus on the accessibility pattern of low-cost housing. The research methodology consists of interview sessions and a questionnaire to residents of low-cost housing areas in Melaka Tengah District in Malaysia. The combination of these processes will show the criteria from the selected parameter for each respondent from their resident area to the employment area. This will further help in the recommendation of several options for a better commute or improvement to the existing routes and public transportations system. Thus enhancing quality of life for employees and helping to reduce stress, decrease lateness, absenteeism and improving productivity in workplace

  11. Reducing employee travelling time through smart commuting

    Science.gov (United States)

    Rahman, A. N. N. A.; Yusoff, Z. M.; Aziz, I. S.; Omar, D.

    2014-02-01

    Extremely congested roads will definitely delay the arrival time of each trip.This certainly impacted the journey of employees. Tardiness at the workplace has become a perturbing issue for companies where traffic jams are the most common worker excuses. A depressing consequence on daily life and productivity of the employee occurs. The issues of commuting distance between workplace and resident area become the core point of this research. This research will emphasize the use of Geographical Information System (GIS) technique to explore the distance parameter to the employment area and will focus on the accessibility pattern of low-cost housing. The research methodology consists of interview sessions and a questionnaire to residents of low-cost housing areas in Melaka Tengah District in Malaysia. The combination of these processes will show the criteria from the selected parameter for each respondent from their resident area to the employment area. This will further help in the recommendation of several options for a better commute or improvement to the existing routes and public transportations system. Thus enhancing quality of life for employees and helping to reduce stress, decrease lateness, absenteeism and improving productivity in workplace.

  12. Work-related accidents and daylight saving time in Finland.

    Science.gov (United States)

    Lahti, T; Sysi-Aho, J; Haukka, J; Partonen, T

    2011-01-01

    Recent research has indicated that transitions into and out of daylight saving time (DST) unbalance the physiological circadian rhythm and may lead to sleep disturbance. Sleep deprivation may have negative effects on motivation, attention and alertness and thus it is possible that transitions into and out of DST may increase accident rates. To explore the impact of DST transitions on the number of occupational accidents in Finland. For the study, we analysed all occupational accidents that happened in Finland 1 week before and 1 week after DST transitions during the years 2002-06. Transitions into and out of DST did not significantly increase the number of occupational accidents. It seems that sleep deprivation after DST transition is not harmful enough to impact on occupational accident rates.

  13. Save Time and Money through Chemistry (by Ken Carpenter)

    Science.gov (United States)

    Hazari, Al

    1998-01-01

    Useful Chemistry Publishing: Dayton, OH, 1997. 261 pp. Figs. and tables. ISBN: 0965566714. $24.95 (soft cover only). Would you like to learn about the 5 W's of everyday chemistry and chemicals? Who(m) should you see to learn to identify and appraise jewelry? What should you eat for breakfast? When should you get up from your sleep? Where is cholesterol in the human body? Why do pool owners add hydrochloric acid? Then read Save Time and Money through Chemistry, by Ken Carpenter. This book is loaded with practical and useful chemistry information that every person who took chemistry in high school or college wishes he or she had been introduced or exposed to. I know I do.

  14. Bayesian Travel Time Inversion adopting Gaussian Process Regression

    Science.gov (United States)

    Mauerberger, S.; Holschneider, M.

    2017-12-01

    A major application in seismology is the determination of seismic velocity models. Travel time measurements are putting an integral constraint on the velocity between source and receiver. We provide insight into travel time inversion from a correlation-based Bayesian point of view. Therefore, the concept of Gaussian process regression is adopted to estimate a velocity model. The non-linear travel time integral is approximated by a 1st order Taylor expansion. A heuristic covariance describes correlations amongst observations and a priori model. That approach enables us to assess a proxy of the Bayesian posterior distribution at ordinary computational costs. No multi dimensional numeric integration nor excessive sampling is necessary. Instead of stacking the data, we suggest to progressively build the posterior distribution. Incorporating only a single evidence at a time accounts for the deficit of linearization. As a result, the most probable model is given by the posterior mean whereas uncertainties are described by the posterior covariance.As a proof of concept, a synthetic purely 1d model is addressed. Therefore a single source accompanied by multiple receivers is considered on top of a model comprising a discontinuity. We consider travel times of both phases - direct and reflected wave - corrupted by noise. Left and right of the interface are assumed independent where the squared exponential kernel serves as covariance.

  15. Investigating Unsaturated Zone Travel Times with Tritium and Stable Isotopes

    Science.gov (United States)

    Visser, A.; Thaw, M.; Van der Velde, Y.

    2017-12-01

    Travel times in the unsaturated zone are notoriously difficult to assess. Travel time tracers relying on the conservative transport of dissolved (noble) gases (tritium-helium, CFCs or SF6) are not applicable. Large water volume requirements of other cosmogenic radioactive isotopes (sulfur-35, sodium-22) preclude application in the unsaturated zone. Prior investigations have relied on models, introduced tracers, profiles of stable isotopes or tritium, or a combination of these techniques. Significant unsaturated zone travel times (UZTT) complicate the interpretation of stream water travel time tracers by ranked StorAge Selection (rSAS) functions. Close examination of rSAS functions in a sloping soil lysimeter[1] show the effect of the UZTT on the shape of the rSAS cumulative distribution function. We studied the UZTT at the Southern Sierra Critical Zone Observatory (SS-CZO) using profiles of tritium and stable isotopes (18O and 2H) in the unsaturated zone, supported by soil water content data. Tritium analyses require 100-500 mL of soil water and therefore large soil samples (1-5L), and elaborate laboratory procedures (oven drying, degassing and noble gas mass spectrometry). The high seasonal and interannual variability in precipitation of the Mediterranean climate, variable snow pack and high annual ET/P ratios lead to a dynamic hydrology in the deep unsaturated soils and regolith and highly variable travel time distributions. Variability of the tritium concentration in precipitation further complicates direct age estimates. Observed tritium profiles (>3 m deep) are interpreted in terms of advective and dispersive vertical transport of the input variability and radioactive decay of tritium. Significant unsaturated zone travel times corroborate previously observed low activities of short-lived cosmogenic radioactive nuclides in stream water. Under these conditions, incorporating the UZTT is critical to adequately reconstruct stream water travel time distributions. 1

  16. Connected Traveler

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Alex

    2015-11-01

    The Connected Traveler project is a multi-disciplinary undertaking that seeks to validate potential for transformative transportation system energy savings by incentivizing efficient traveler behavior. This poster outlines various aspects of the Connected Traveler project, including market opportunity, understanding traveler behavior and decision-making, automation and connectivity, and a projected timeline for Connected Traveler's key milestones.

  17. Similarity-Based Prediction of Travel Times for Vehicles Traveling on Known Routes

    DEFF Research Database (Denmark)

    Tiesyte, Dalia; Jensen, Christian Søndergaard

    2008-01-01

    The use of centralized, real-time position tracking is proliferating in the areas of logistics and public transportation. Real-time positions can be used to provide up-to-date information to a variety of users, and they can also be accumulated for uses in subsequent data analyses. In particular......, historical data in combination with real-time data may be used to predict the future travel times of vehicles more accurately, thus improving the experience of the users who rely on such information. We propose a Nearest-Neighbor Trajectory (NNT) technique that identifies the historical trajectory...

  18. The Electric Traveling Salesman Problem with Time Windows

    DEFF Research Database (Denmark)

    Roberti, Roberto; Wen, Min

    2016-01-01

    To minimize greenhouse gas emissions, the logistic field has seen an increasing usage of electric vehicles. The resulting distribution planning problems present new computational challenges.We address a problem, called Electric Traveling Salesman Problem with Time Windows. We propose a mixed...

  19. A simple data fusion method for instantaneous travel time estimation

    NARCIS (Netherlands)

    Do, Michael; Pueboobpaphan, R.; Miska, Marc; Kuwahara, Masao; van Arem, Bart; Viegas, J.M.; Macario, R.

    2010-01-01

    Travel time is one of the most understandable parameters to describe traffic condition and an important input to many intelligent transportation systems applications. Direct measurement from Electronic Toll Collection (ETC) system is promising but the data arrives too late, only after the vehicles

  20. Flow calculations for Yucca Mountain groundwater travel time (GWTT-95)

    Energy Technology Data Exchange (ETDEWEB)

    Altman, S.J.; Arnold, B.W.; Barnard, R.W.; Barr, G.E.; Ho, C.K.; McKenna, S.A.; Eaton, R.R.

    1996-09-01

    In 1983, high-level radioactive waste repository performance requirements related to groundwater travel time were defined by NRC subsystem regulation 10 CFR 60.113. Although DOE is not presently attempting to demonstrate compliance with that regulation, understanding of the prevalence of fast paths in the groundwater flow system remains a critical element of any safety analyses for a potential repository system at Yucca Mountain, Nevada. Therefore, this analysis was performed to allow comparison of fast-path flow against the criteria set forth in the regulation. Models developed to describe the conditions for initiation, propagation, and sustainability of rapid groundwater movement in both the unsaturated and saturated zones will form part of the technical basis for total- system analyses to assess site viability and site licensability. One of the most significant findings is that the fastest travel times in both unsaturated and saturated zones are in the southern portion of the potential repository, so it is recommended that site characterization studies concentrate on this area. Results support the assumptions regarding the importance of an appropriate conceptual model of groundwater flow and the incorporation of heterogeneous material properties into the analyses. Groundwater travel times are sensitive to variation/uncertainty in hydrologic parameters and in infiltration flux at upper boundary of the problem domain. Simulated travel times are also sensitive to poorly constrained parameters of the interaction between flow in fractures and in the matrix.

  1. Real-time traveler information market assessment white paper.

    Science.gov (United States)

    2010-02-22

    This report takes a multi-modal look at the lay of the land of the real-time traveler information : market in the United States. This includes identification and characterization of the gaps in the : domestic industry with respect to data cover...

  2. Global travel time tomography with 3-D reference models

    NARCIS (Netherlands)

    Amaru, M.L.

    2007-01-01

    In this study, a global high-resolution P-wave velocity model is obtained for the Earth's crust and mantle using travel time tomography. Improvements to previous models are achieved by incorporating additional data and advancing the method to use 3-D reference models. The newly compiled data set

  3. Extending Regional Seismic Travel Time (RSTT) Tomography to New Regions

    Science.gov (United States)

    2011-09-01

    Seism . Soc. Am. 59, 1365–1398. Flanagan, M. P., D. A. Dodge, and S. C. Myers (2008). GT merge process: Version 2.0, LLNL technical report, LLNL-TR...Validation of regional and teleseismic travel-time models by relocating ground-truth events, Bull. Seism . Soc. Amer. 94: 897–919. Zhao, L.-S. (1993

  4. Special-purpose travel in ancient times: 'Tourism' before tourism?

    Directory of Open Access Journals (Sweden)

    Rabotić Branislav

    2014-01-01

    Full Text Available Tourism is generally regarded as a quite recent phenomenon, but researchers and scholars do not agree on its historical roots: some relate them to the mid-nineteenth century progress of transport infrastructure and the availability of leisure time, others to the Grand Tour as a particular type of aristocratic travel in the 17-18th centuries, and some even to mediaeval pilgrimages. However, trips similar to today's tourism were made as early as during the ancient period, when people travelled not only for trade and business, religion, sports, health, education and other specific reasons, but also for leisure and pleasure involving sightseeing of the new and unfamiliar areas. The aim of this paper is to bring together the insights of the literature on travel in the ancient Graeco-Roman world and, particularly, on special-purpose trips which might be seen as a distant forerunner of some modern forms of tourism.

  5. How to build a time machine: the real science of time travel

    CERN Document Server

    Clegg, Brian

    2013-01-01

    A pop science look at time travel technology, from Einstein to Ronald Mallett to present day experiments. Forget fiction: time travel is real.In How to Build a Time Machine, Brian Clegg provides an understanding of what time is and how it can be manipulated. He explores the fascinating world of physics and the remarkable possibilities of real time travel that emerge from quantum entanglement, superluminal speeds, neutron star cylinders and wormholes in space. With the fascinating paradoxes of time travel echoing in our minds will we realize that travel into the future might never be possible? Or will we realize there is no limit on what can be achieved, and take on this ultimate challenge? Only time will tell.

  6. Consequences of mixing assumptions for time-variable travel time distributions

    NARCIS (Netherlands)

    Velde, van der Y.; Heidbüchel, I.; Lyon, S.W.; Nyberg, L.; Rodhe, A.; Bishop, K.; Troch, P.A.

    2015-01-01

    The current generation of catchment travel time distribution (TTD) research, integrating nearly three decades of work since publication of Water's Journey from Rain to Stream, seeks to represent the full distribution in catchment travel times and its temporal variability. Here, we compare

  7. Real-time travel time prediction framework for departure time and route advice

    NARCIS (Netherlands)

    Calvert, S.C.; Snelder, M.; Bakri, T.; Heijligers, B.; Knoop, V.L.

    2015-01-01

    Heavily used urban networks remain a challenge for travel time prediction because traffic flow is rarely homogeneous and is also subject to a wide variety of disturbances. Various models, some of which use traffic flow theory and some of which are data driven, have been developed to predict traffic

  8. Is average daily travel time expenditure constant? In search of explanations for an increase in average travel time.

    NARCIS (Netherlands)

    van Wee, B.; Rietveld, P.; Meurs, H.

    2006-01-01

    Recent research suggests that the average time spent travelling by the Dutch population has increased over the past decades. However, different data sources show different levels of increase. This paper explores possible causes for this increase. They include a rise in incomes, which has probably

  9. A method for generating an illusion of backwards time travel using immersive virtual reality-an exploratory study.

    Science.gov (United States)

    Friedman, Doron; Pizarro, Rodrigo; Or-Berkers, Keren; Neyret, Solène; Pan, Xueni; Slater, Mel

    2014-01-01

    We introduce a new method, based on immersive virtual reality (IVR), to give people the illusion of having traveled backwards through time to relive a sequence of events in which they can intervene and change history. The participant had played an important part in events with a tragic outcome-deaths of strangers-by having to choose between saving 5 people or 1. We consider whether the ability to go back through time, and intervene, to possibly avoid all deaths, has an impact on how the participant views such moral dilemmas, and also whether this experience leads to a re-evaluation of past unfortunate events in their own lives. We carried out an exploratory study where in the "Time Travel" condition 16 participants relived these events three times, seeing incarnations of their past selves carrying out the actions that they had previously carried out. In a "Repetition" condition another 16 participants replayed the same situation three times, without any notion of time travel. Our results suggest that those in the Time Travel condition did achieve an illusion of "time travel" provided that they also experienced an illusion of presence in the virtual environment, body ownership, and agency over the virtual body that substituted their own. Time travel produced an increase in guilt feelings about the events that had occurred, and an increase in support of utilitarian behavior as the solution to the moral dilemma. Time travel also produced an increase in implicit morality as judged by an implicit association test. The time travel illusion was associated with a reduction of regret associated with bad decisions in their own lives. The results show that when participants have a third action that they can take to solve the moral dilemma (that does not immediately involve choosing between the 1 and the 5) then they tend to take this option, even though it is useless in solving the dilemma, and actually results in the deaths of a greater number.

  10. A properly adjusted forage harvester can save time and money

    Science.gov (United States)

    A properly adjusted forage harvester can save fuel and increase the realizable milk per ton of your silage. This article details the adjustments necessary to minimize energy while maximizing productivity and forage quality....

  11. Modelling travel and residence times in the eastern Irish Sea

    International Nuclear Information System (INIS)

    Dabrowski, T.; Hartnett, M.

    2008-01-01

    The Irish Sea, which lies between 51 deg. N-56 deg. N and 2 deg. 50'W-7 deg. W, provides a sheltered environment to exploit valuable fisheries resource. Anthropogenic activity is a real threat to its water quality. The majority of freshwater input down rivers flows into the eastern Irish Sea. The structure of the water circulation was not well understood during the planning of Sellafield nuclear plant outfall site in the eastern Irish Sea. A three-dimensional primitive equation numerical model was applied to the Irish Sea to simulate both barotropic and baroclinic circulation within the region. High accuracy was achieved with regard to the prediction of both tidal circulation and surface and nearbed water temperatures across the region. The model properly represented the Western Irish Sea Gyre, induced by thermal stratification and not known during planning Sellafield. Passive tracer simulations based on the developed hydrodynamic model were used to deliver residence times of the eastern Irish Sea region for various times of the year as well as travel times from the Sellafield outfall site to various locations within the Irish Sea. The results indicate a strong seasonal variability of travel times from Sellafield to the examined locations. Travel time to the Clyde Sea is the shortest for the autumnal tracer release (90 days); it takes almost a year for the tracer to arrive at the same location if it is released in January. Travel times from Sellafield to Dublin Bay fall within the range of 180-360 days. The average residence time of the entire eastern Irish Sea is around 7 months. The areas surrounding the Isle of Man are initially flushed due to a predominant northward flow; a backwater is formed in Liverpool Bay. Thus, elevated tracer concentrations are predicted in Liverpool Bay in the case of accidental spills at the Sellafield outfall site

  12. Accident rates and the impact of daylight saving time transitions.

    Science.gov (United States)

    Robb, David; Barnes, Thomas

    2018-02-01

    One-third of nations have adopted some form of Daylight Saving Time (DST). Associated costs and benefits include impacts on accident rates. Using data from 12.6 million accident claims in New Zealand during 2005-2016, we model accident rates as a function of various date-based predictors including days before/after the start and end of DST, holidays, day of week, and month of year. This is the first study to consider multiple accident categories (Road, Work, Falls and Home & Community), and the first in the southern hemisphere. The start of DST is associated with significantly higher rates of road accidents (first day +16% and second day +12%). Evidence that accident rates for Falls and Home & Community decline (increase) prior to the start (end) of DST suggest potential behavioural adaption from anticipating the change. While Work accidents show limited impact from DST changes, they exhibit a significant decline over the course of the week (Friday 13% lower than Monday), whereas Road accidents exhibit a significant increase (Friday 19% higher than Monday). Our results have implications for both DST implementation and policy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. The cost of travel time variability: three measures with properties

    DEFF Research Database (Denmark)

    Engelson, Leonid; Fosgerau, Mogens

    2016-01-01

    This paper explores the relationships between three types of measures of the cost of travel time variability: measures based on scheduling preferences and implicit departure time choice, Bernoulli type measures based on a univariate function of travel time, and mean-dispersion measures. We...... characterise measures that are both scheduling measures and mean-dispersion measures and measures that are both Bernoulli and mean-dispersion. There are no measures that are both scheduling and Bernoulli. We consider the impact of requiring that measures are additive or homogeneous, proving also a new strong...... result on the utility rates in an additive scheduling measure. These insights are useful for selecting cost measures to use in applications....

  14. Time machine tales the science fiction adventures and philosophical puzzles of time travel

    CERN Document Server

    Nahin, Paul J

    2017-01-01

    This book contains a broad overview of time travel in science fiction, along with a detailed examination of the philosophical implications of time travel. The emphasis of this book is now on the philosophical and on science fiction, rather than on physics, as in the author's earlier books on the subject. In that spirit there are, for example, no Tech Notes filled with algebra, integrals, and differential equations, as there are in the first and second editions of TIME MACHINES. Writing about time travel is, today, a respectable business. It hasn’t always been so. After all, time travel, prima facie, appears to violate a fundamental law of nature; every effect has a cause, with the cause occurring before the effect. Time travel to the past, however, seems to allow, indeed to demand, backwards causation, with an effect (the time traveler emerging into the past as he exits from his time machine) occurring before its cause (the time traveler pushing the start button on his machine’s control panel to start his...

  15. Test plan : Branson TRIP travel time/data accuracy

    Science.gov (United States)

    1998-06-01

    The Branson Travel and Recreational Information Program (TRIP) in Branson, Missouri, and the I-40 Traveler and Tourist Information System (TTIS) in the I-40 corridor of Northern Arizona are two Field Operational Tests (FOTs) of Traveler Information S...

  16. Quantifying catchment-scale mixing and its effect on time-varying travel time distributions

    NARCIS (Netherlands)

    Van Der Velde, Y.; Torfs, P. J J F; Van Der Zee, S. E A T M; Uijlenhoet, R.

    2012-01-01

    Travel time distributions are often used to characterize catchment discharge behavior, catchment vulnerability to pollution and pollutant loads from catchments to downstream waters. However, these distributions vary with time because they are a function of rainfall and evapotranspiration. It is

  17. Congestion relief by travel time minimization in near real time : Detroit area I-75 corridor study.

    Science.gov (United States)

    2008-12-01

    "This document summarizes the activities concerning the project: Congestion Relief by : Travel Time Minimization in Near Real Time -- Detroit Area I-75 Corridor Study since : the inception of the project (Nov. 22, 2006 through September 30, 2008). : ...

  18. Mental time travel: a case for evolutionary continuity.

    Science.gov (United States)

    Corballis, Michael C

    2013-01-01

    In humans, hippocampal activity responds to the imagining of past or future events. In rats, hippocampal activity is tied to particular locations in a maze, occurs after the animal has been in the maze, and sometimes corresponds to locations the animal did not actually visit. This suggests that mental time travel has neurophysiological underpinnings that go far back in evolution, and may not be, as some (including myself) have claimed, unique to humans. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Change of Measure between Light Travel Time and Euclidean Distances

    Directory of Open Access Journals (Sweden)

    Heymann Y.

    2013-04-01

    Full Text Available The problem of cosmological distances is approached using a method based on the propagation of light in an expanding Universe. From the chan ge of measure between Light Travel Time and Euclidean Distances, a formula is deri ved to compute distances as a function of redshift. This formula is identical to Matti g’s formula (with q 0 = 1 / 2 which is based on Friedmann’s equations of general relativi ty.

  20. Uncertainty analyses of unsaturated zone travel time at Yucca Mountain

    International Nuclear Information System (INIS)

    Nichols, W.E.; Freshley, M.D.

    1993-01-01

    Uncertainty analysis method can be applied to numerical models of ground-water flow to estimate the relative importance of physical and hydrologic input variables with respect to ground-water travel time. Monte Carlo numerical simulations of unsaturated flow in the Calico Hills nonwelded zeolitic (CHnz) layer at Yucca Mountain, Nevada, indicate that variability in recharge, and to a lesser extent in matrix porosity, explains most of the variability in predictions of water travel time through the unsaturated zone. Variations in saturated hydraulic conductivity and unsaturated curve-fitting parameters were not statistically significant in explaining variability in water travel time through the unsaturated CHnz unit. The results of this study suggest that the large uncertainty associated with recharge rate estimates for the Yucca Mountain site is of concern because the performance of the potential repository would be more sensitive to uncertainty in recharge than to any other parameter evaluated. These results are not exhaustive because of the limited site characterization data available and because of the preliminary nature of this study, which is limited to a single stratigraphic unit, one dimension, and does not account for fracture flow or other potential fast pathways at Yucca Mountain

  1. [Mental time travel - the neurocognitive basis of future thinking].

    Science.gov (United States)

    Weiler, Julia A; Daum, Irene

    2008-09-01

    The ability to travel in time mentally, i. e. the re-experiencing of personal past events as well as the ability to mentally simulate potential future events, forms part of the "episodic memory" concept. Evidence for the notion that episodic memory and episodic future thinking share a common neural basis stems from different lines of research, namely functional neuroimaging, assessment of clinical groups, behavioral investigations of the phenomenological characteristics of mental time travel, and developmental research. The present article summarises the evidence from these lines of research which indicate a common neural network underlying episodic memory and episodic future thinking, consisting of medial prefrontal, medial temporal, medial parietal, lateral parieto-occipital, as well as lateral temporal regions. Both abilities, episodic memory and future thinking, seem to develop around the age of four years, feature similar phenomenological characteristics, and are impaired to a similar extent by brain lesions and brain dysfunction. These findings yielded different hypotheses concerning the function and evolutional significance of the mental time travel network, which will also be addressed.

  2. Intelligent Patient Education: Saving Time and Increasing Nurses Efficiency

    Directory of Open Access Journals (Sweden)

    Rafat Rezapour-Nasrabad

    2017-07-01

    Full Text Available Background: Patient education completes value chain process in presenting therapy and care services to patients. Thus, it is necessary to use the latest technologies in patients’ education. The present study aims to design an educational software to provide the verified scientific, educational and care data of the patients.Methods: The software is performed in three stages:1-      Formation of databases including the nursing care based on the latest educational and care standards2-      Design an intelligent software to present care education based on nursing process3-      For pilot study, the relevant software is installed on some systems and it is used in at least three hospitals.Results: The mentioned software presents valuable data in accordance to the needs of patients. Some of the advantages of this software include:-          Customization of education as their reading is easier.-          Simplicity of use with software can increase the availability of data for the patients.-          This software helps the nurses to guide the patients to receive the trainings in each stage of care process.Conclusion: Implementation of intelligent education system of patient reduces the frequency of visit to health centers and unnecessary admissions and this effectiveness cost of this system can save time and energy of disabled patients and increase the efficiency of nurses.

  3. Bi-criteria travelling salesman subtour problem with time threshold

    Science.gov (United States)

    Kumar Thenepalle, Jayanth; Singamsetty, Purusotham

    2018-03-01

    This paper deals with the bi-criteria travelling salesman subtour problem with time threshold (BTSSP-T), which comes from the family of the travelling salesman problem (TSP) and is NP-hard in the strong sense. The problem arises in several application domains, mainly in routing and scheduling contexts. Here, the model focuses on two criteria: total travel distance and gains attained. The BTSSP-T aims to determine a subtour that starts and ends at the same city and visits a subset of cities at a minimum travel distance with maximum gains, such that the time spent on the tour does not exceed the predefined time threshold. A zero-one integer-programming problem is adopted to formulate this model with all practical constraints, and it includes a finite set of feasible solutions (one for each tour). Two algorithms, namely, the Lexi-Search Algorithm (LSA) and the Tabu Search (TS) algorithm have been developed to solve the BTSSP-T problem. The proposed LSA implicitly enumerates the feasible patterns and provides an efficient solution with backtracking, whereas the TS, which is metaheuristic, will give the better approximate solution. A numerical example is demonstrated in order to understand the search mechanism of the LSA. Numerical experiments are carried out in the MATLAB environment, on the different benchmark instances available in the TSPLIB domain as well as on randomly generated test instances. The experimental results show that the proposed LSA works better than the TS algorithm in terms of solution quality and, computationally, both LSA and TS are competitive.

  4. Model Passengers’ Travel Time for Conventional Bus Stop

    Directory of Open Access Journals (Sweden)

    Guangzhao Xin

    2014-01-01

    Full Text Available Limited number of berths can result in a subsequent bus stopping at the upstream of a bus stop when all berths are occupied. When this traffic phenomenon occurs, passengers waiting on the platform usually prefer walking to the stopped bus, which leads to additional walking time before boarding the bus. Therefore, passengers’ travel time consumed at a bus stop is divided into waiting time, additional walking time, and boarding time. This paper proposed a mathematical model for analyzing passengers’ travel time at conventional bus stop based on theory of stochastic service system. Field-measured and simulated data were designated to demonstrate the effectiveness of the proposed model. By analyzing the results, conclusion was conducted that short headway can reduce passengers’ waiting time at bus stop. Meanwhile, the theoretical analysis explained the inefficiency of bus stops with more than three berths from the perspective of passengers’ additional walking time. Additional walking time will increase in a large scale when the number of berths at a bus stop exceedsthe threshold of three.

  5. Daylight saving time transitions and hospital treatments due to accidents or manic episodes

    OpenAIRE

    Lahti, Tuuli A; Haukka, Jari; Lönnqvist, Jouko; Partonen, Timo

    2008-01-01

    Abstract Background Daylight saving time affects millions of people annually but its impacts are still widely unknown. Sleep deprivation and the change of circadian rhythm can trigger mental illness and cause higher accident rates. Transitions into and out of daylight saving time changes the circadian rhythm and may cause sleep deprivation. Thus it seems plausible that the prevalence of accidents and/or manic episodes may be higher after transition into and out of daylight saving time. The ai...

  6. Defense Travel System: Estimated Savings are Questionable and Improvements are Needed to Ensure Functionality and Increase Utilization

    Science.gov (United States)

    2006-11-16

    end travel system for business travel . DTS’s reported utilization rates for the period October 2005 through April 2006 averaged 53 percent for...endeavor, should help in making DTS the standard integrated, end-to-end travel system for business travel . Management oversight is essential for this to

  7. On a `time' reparametrization in relativistic electrodynamics with travelling waves

    Science.gov (United States)

    Fiore, Gaetano

    2018-01-01

    We briefly report on our method [23] of simplifying the equations of motion of charged particles in an electromagnetic (EM) field that is the sum of a plane travelling wave and a static part; it is based on changes of the dependent variables and the independent one (light-like coordinate ξ instead of time t). We sketch its application to a few cases of extreme laser-induced accelerations, both in vacuum and in plane problems at the vacuum-plasma interface, where we are able to reduce the system of the (Lorentz-Maxwell and continuity) partial differential equations into a family of decoupled systems of Hamilton equations in 1 dimension. Since Fourier analysis plays no role, the method can be applied to all kind of travelling waves, ranging from almost monochromatic to socalled "impulses".

  8. Time series analysis of travel trends in Vermont

    Science.gov (United States)

    Varna M. Ramaswamy; Walter F. Kuentzel

    1995-01-01

    Vermont's travel and tourism industry is not keeping pace with the nation-wide growth in the travel industry. While travel indicators such as domestic travel expenditures, tourism generated employment, payroll and tax receipts have been steadily increasing across the United States, these indicators in Vermont peaked in 1978 and have declined ever since. The state...

  9. Valuation of travel time for international long-distance travel - results from the Fehmarn Belt stated choice experiment

    DEFF Research Database (Denmark)

    Mabit, Stefan Lindhard; Rich, Jeppe; Burge, Peter

    2013-01-01

    significant interactions among travel cost and time, and journey characteristics, such as distance and duration. This had direct impact on the VTTS, which was shown to decrease with distance and duration. Thirdly, we found that air travel implies a higher average VTTS, which is to be expected but rarely...

  10. Optimizing Travel Time to Outpatient Interventional Radiology Procedures in a Multi-Site Hospital System Using a Google Maps Application.

    Science.gov (United States)

    Mandel, Jacob E; Morel-Ovalle, Louis; Boas, Franz E; Ziv, Etay; Yarmohammadi, Hooman; Deipolyi, Amy; Mohabir, Heeralall R; Erinjeri, Joseph P

    2018-02-20

    The purpose of this study is to determine whether a custom Google Maps application can optimize site selection when scheduling outpatient interventional radiology (IR) procedures within a multi-site hospital system. The Google Maps for Business Application Programming Interface (API) was used to develop an internal web application that uses real-time traffic data to determine estimated travel time (ETT; minutes) and estimated travel distance (ETD; miles) from a patient's home to each a nearby IR facility in our hospital system. Hypothetical patient home addresses based on the 33 cities comprising our institution's catchment area were used to determine the optimal IR site for hypothetical patients traveling from each city based on real-time traffic conditions. For 10/33 (30%) cities, there was discordance between the optimal IR site based on ETT and the optimal IR site based on ETD at non-rush hour time or rush hour time. By choosing to travel to an IR site based on ETT rather than ETD, patients from discordant cities were predicted to save an average of 7.29 min during non-rush hour (p = 0.03), and 28.80 min during rush hour (p Google Maps application to schedule outpatients for IR procedures can effectively reduce patient travel time when more than one location providing IR procedures is available within the same hospital system.

  11. Travelling

    African Journals Online (AJOL)

    homes very soon becomes a misplaced sentiment. However well planned a journey may be and how- ever important and tiring the attendances at meet- ings are, at some stage of every day the traveller finds himself in an hotel room and loneliness starts closing in from all four walls. No matter how luxu- rious the hotel may ...

  12. Roads, travel, and time ‘across Jordan' in Byzantine and early Islamic times

    DEFF Research Database (Denmark)

    Walmsley, Alan George

    2009-01-01

    Roads, means of travel and travel times required to journey from one place to another in antiquity are essential components in assessing the political, cultural and economic history of a region. This paper reviews archaeological and documentary material detailing the major routes that crossed...... Jordan, the manner in which they were transversed, and the time required to travel over them in the period ca. 300-800 CE. In this post-Roman period, roadways took on new meaning as the needs of empire gave way to wider, and more self-defining, social and economic requirements of late antiquity...

  13. Impact of Extended Daylight Saving Time on National Energy Consumption Report to Congress

    Energy Technology Data Exchange (ETDEWEB)

    Belzer, D. B.; Hadley, S. W.; Chin, S-M.

    2008-10-01

    The Energy Policy Act of 2005 (Pub. L. No. 109-58; EPAct 2005) amended the Uniform Time Act of 1966 (Pub. L. No. 89-387) to increase the portion of the year that is subject to Daylight Saving Time. (15 U.S.C. 260a note) EPAct 2005 extended the duration of Daylight Saving Time in the spring by changing its start date from the first Sunday in April to the second Sunday in March, and in the fall by changing its end date from the last Sunday in October to the first Sunday in November. (15 U.S.C. 260a note) EPAct 2005 also called for the Department of Energy to evaluate the impact of Extended Daylight Saving Time on energy consumption in the United States and to submit a report to Congress. (15 U.S.C. 260a note) This report presents the results of impacts of Extended Daylight Saving Time on the national energy consumption in the United States. The key findings are: (1) The total electricity savings of Extended Daylight Saving Time were about 1.3 Tera Watt-hour (TWh). This corresponds to 0.5 percent per each day of Extended Daylight Saving Time, or 0.03 percent of electricity consumption over the year. In reference, the total 2007 electricity consumption in the United States was 3,900 TWh. (2) In terms of national primary energy consumption, the electricity savings translate to a reduction of 17 Trillion Btu (TBtu) over the spring and fall Extended Daylight Saving Time periods, or roughly 0.02 percent of total U.S. energy consumption during 2007 of 101,000 TBtu. (3) During Extended Daylight Saving Time, electricity savings generally occurred over a three- to five-hour period in the evening with small increases in usage during the early-morning hours. On a daily percentage basis, electricity savings were slightly greater during the March (spring) extension of Extended Daylight Saving Time than the November (fall) extension. On a regional basis, some southern portions of the United States exhibited slightly smaller impacts of Extended Daylight Saving Time on energy savings

  14. A comparative analysis of short-range travel time prediction methods

    NARCIS (Netherlands)

    Huisken, Giovanni; van Berkum, Eric C.

    2003-01-01

    Increasing car mobility has lead to an increasing demand for traffic information. This contribution deals with information about travel times. When car drivers are provided with this type of information, the travel times should ideally be the times that they will encounter. As a result travel times

  15. Comparison of methods for measuring travel time at Florida freeways and arterials.

    Science.gov (United States)

    2014-07-01

    Travel time is an important performance measure used to assess the traffic operational quality of various types of highway : facilities. Previous research funded by the Florida Department of Transportation (FDOT) on travel time reliability developed,...

  16. Arterial link travel time estimation using loop detector data : phase 1

    Science.gov (United States)

    1997-11-01

    The envisioned operational tests of Advanced Traveler Information Systems (ATIS) and Advanced Traffic Management Systems (ATMS) in the Minneapolis/St. Paul area call for the provision of timely and reliable travel times over an entire rod network. Un...

  17. Assessing segment- and corridor-based travel-time reliability on urban freeways : final report.

    Science.gov (United States)

    2016-09-01

    Travel time and its reliability are intuitive performance measures for freeway traffic operations. The objective of this project was to quantify segment-based and corridor-based travel time reliability measures on urban freeways. To achieve this obje...

  18. Completion of construction and installation of travel time signs on I-35 in Austin : project summary.

    Science.gov (United States)

    2015-08-31

    Drivers desire real-time information when : traveling in order to make route choice : decisions. One type of information that can be : provided is current (dynamic) travel times on : two possible routes that serve a common : destination. In this way,...

  19. Innovative methods for calculation of freeway travel time using limited data : final report.

    Science.gov (United States)

    2008-01-01

    Description: Travel time estimations created by processing of simulated freeway loop detector data using proposed method have been compared with travel times reported from VISSIM model. An improved methodology was proposed to estimate freeway corrido...

  20. Freeway travel time estimation using existing fixed traffic sensors : phase 2.

    Science.gov (United States)

    2015-03-01

    Travel time, one of the most important freeway performance metrics, can be easily estimated using the : data collected from fixed traffic sensors, avoiding the need to install additional travel time data collectors. : This project is aimed at fully u...

  1. Validation and augmentation of Inrix arterial travel time data using independent sources.

    Science.gov (United States)

    2015-02-01

    Travel time data is a key input to Intelligent Transportation Systems (ITS) applications. Advancement in vehicle : tracking and identification technologies and proliferation of location-aware and connected devices has made network-wide travel time da...

  2. Construction and installation of travel time signs on I-35 in Austin.

    Science.gov (United States)

    2016-08-01

    Dynamic travel time signs (DTTS) provide current travel times to a specific destination via one or more : routes. These signs aid motorists in making route choice decisions en route. Through this project, three : DTTS were fabricated and installed on...

  3. DOTD support for UTC project : travel time estimation using bluetooth, [research project capsule].

    Science.gov (United States)

    2013-10-01

    Travel time estimates are useful tools for measuring congestion in an urban area. Current : practice involves using probe vehicles or video cameras to measure travel time, but this is a laborintensive and expensive means of obtaining the information....

  4. Characterizing Global Flood Wave Travel Times to Optimize the Utility of Near Real-Time Satellite Remote Sensing Products

    Science.gov (United States)

    Allen, G. H.; David, C. H.; Andreadis, K. M.; Emery, C. M.; Famiglietti, J. S.

    2017-12-01

    Earth observing satellites provide valuable near real-time (NRT) information about flood occurrence and magnitude worldwide. This NRT information can be used in early flood warning systems and other flood management applications to save lives and mitigate flood damage. However, these NRT products are only useful to early flood warning systems if they are quickly made available, with sufficient time for flood mitigation actions to be implemented. More specifically, NRT data latency, or the time period between the satellite observation and when the user has access to the information, must be less than the time it takes a flood to travel from the flood observation location to a given downstream point of interest. Yet the paradigm that "lower latency is always better" may not necessarily hold true in river systems due to tradeoffs between data latency and data quality. Further, the existence of statistical breaks in the global distribution of flood wave travel time (i.e. a jagged statistical distribution) would represent preferable latencies for river-observation NRT remote sensing products. Here we present a global analysis of flood wave velocity (i.e. flow celerity) and travel time. We apply a simple kinematic wave model to a global hydrography dataset and calculate flow wave celerity and travel time during bankfull flow conditions. Bankfull flow corresponds to the condition of maximum celerity and thus we present the "worst-case scenario" minimum flow wave travel time. We conduct a similar analysis with respect to the time it takes flood waves to reach the next downstream city, as well as the next downstream reservoir. Finally, we conduct these same analyses, but with regards to the technical capabilities of the planned Surface Water and Ocean Topography (SWOT) satellite mission, which is anticipated to provide waterbody elevation and extent measurements at an unprecedented spatial and temporal resolution. We validate these results with discharge records from paired

  5. Children’s Mental Time Travel during Mind Wandering

    Directory of Open Access Journals (Sweden)

    Qun eYe

    2014-08-01

    Full Text Available The prospective bias is a salient feature of mind wandering in healthy adults, yet little is known about the temporal focus of children’s mind wandering. In the present study, (I we developed the Temporal Focus of Mind Wandering Questionnaire for school-age children (TFMWQ-C, a 12-item scale with good test-retest reliability and construct validity. (II The criterion validity was tested by thought sampling in both Choice Reaction Time Task (CRT and Working Memory Task (WMT. A positive correlation was found between the temporal focus measured by the questionnaire and the one adopted during task-unrelated thoughts (TUTs by thought sampling probes, especially in the trait level of future-oriented mind wandering. At the same time, children who experienced more TUTs tended to show worse behavioral performance during tasks. (III The children in both tasks experienced more future-oriented TUTs than past-oriented ones, which was congruent with the results observed in adults; however, in contrast with previous research on adults, the prospective bias was not influenced by task demands. Together these results indicate that the prospective bias of mind wandering has emerged since the school age (9~13 years old, and that the relationship between mental time travel during mind wandering and the use of cognitive resources differs between children and adults. Our study provides new insights into how this interesting feature of mind wandering may adaptively contribute to the development of children’s mental time travel.

  6. Evaluation of a real-time travel time prediction system in a freeway construction work zone : executive summary.

    Science.gov (United States)

    2001-03-01

    A real-time travel time prediction system (TIPS) was evaluated in a construction work : zone. TIPS includes changeable message signs (CMSs) displaying the travel time and : distance to the end of the work zone to motorists. The travel times displayed...

  7. Evaluation of a real-time travel time prediction system in a freeway construction work zone : final report, March 2001.

    Science.gov (United States)

    2001-03-01

    A real-time travel time prediction system (TIPS) was evaluated in a construction work zone. TIPS includes changeable message signs (CMSs) displaying the travel time and distance to the end of the work zone to motorists. The travel times displayed by ...

  8. Investigation of Bicycle Travel Time Estimation Using Bluetooth Sensors for Low Sampling Rates

    OpenAIRE

    Mei, Zhenyu; Wang, Dianhai; Chen, Jun; Wang, Wei

    2014-01-01

    Filtering the data for bicycle travel time using Bluetooth sensors is crucial to the estimation of link travel times on a corridor. The current paper describes an adaptive filtering algorithm for estimating bicycle travel times using Bluetooth data, with consideration of low sampling rates. The data for bicycle travel time using Bluetooth sensors has two characteristics. First, the bicycle flow contains stable and unstable conditions. Second, the collected data have low sampling rates (less t...

  9. Assessment and refinement of real-time travel time algorithms for use in practice : final report, October 2008.

    Science.gov (United States)

    2008-10-01

    The FHWA has strongly encouraged transportation departments to display travel times on their Dynamic Message Signs (DMS). The Oregon : Department of Transportation (ODOT) currently displays travel time estimates on three DMSs in the Portland metropol...

  10. Monitoring travel times in an urban network using video, GPS and Bluetooth

    NARCIS (Netherlands)

    Jie, L.; Van Zuylen, H.J.; Chunhua, L.; Shoufeng, L.

    2011-01-01

    The travel time is an important measure for the quality of traffic. This paper discusses a few methods to measure or estimate the travel time in urban road networks. First of all, it is important to know that urban travel times display a large variation, so that the measurement of a single (average)

  11. Wireless data collection system for travel time estimation and traffic performance evaluation.

    Science.gov (United States)

    2010-09-01

    Having accurate and continually updated travel time and other performance data for the road and highway system has many benefits. From the perspective of the road users, having real-time updates on travel times will permit better travel and route pla...

  12. The Regularity and Irregularity of Travel: an Analysis of the Consistency of Travel Times Associated with Subsistence, Maintenance and Discretionary Activities

    OpenAIRE

    Longden, Thomas

    2016-01-01

    Regular and irregular travel patterns coincide with different underlying purposes of travel and days of the week. Within this paper, it is shown that the balance between subsistence (i.e. work) and discretionary (i.e. leisure) activities is related to differences in travel patterns and explains consistency across years. Using eight years of time use diary entries this paper finds that travel time related to subsistence activities tends to be regular and stable. In contrast, travel time associ...

  13. NOTE ON TRAVEL TIME SHIFTS DUE TO AMPLITUDE MODULATION IN TIME-DISTANCE HELIOSEISMOLOGY MEASUREMENTS

    International Nuclear Information System (INIS)

    Nigam, R.; Kosovichev, A. G.

    2010-01-01

    Correct interpretation of acoustic travel times measured by time-distance helioseismology is essential to get an accurate understanding of the solar properties that are inferred from them. It has long been observed that sunspots suppress p-mode amplitude, but its implications on travel times have not been fully investigated so far. It has been found in test measurements using a 'masking' procedure, in which the solar Doppler signal in a localized quiet region of the Sun is artificially suppressed by a spatial function, and using numerical simulations that the amplitude modulations in combination with the phase-speed filtering may cause systematic shifts of acoustic travel times. To understand the properties of this procedure, we derive an analytical expression for the cross-covariance of a signal that has been modulated locally by a spatial function that has azimuthal symmetry and then filtered by a phase-speed filter typically used in time-distance helioseismology. Comparing this expression to the Gabor wavelet fitting formula without this effect, we find that there is a shift in the travel times that is introduced by the amplitude modulation. The analytical model presented in this paper can be useful also for interpretation of travel time measurements for the non-uniform distribution of oscillation amplitude due to observational effects.

  14. Comparison of Travel-Time and Amplitude Measurements for Deep-Focusing Time-Distance Helioseismology

    Science.gov (United States)

    Pourabdian, Majid; Fournier, Damien; Gizon, Laurent

    2018-04-01

    The purpose of deep-focusing time-distance helioseismology is to construct seismic measurements that have a high sensitivity to the physical conditions at a desired target point in the solar interior. With this technique, pairs of points on the solar surface are chosen such that acoustic ray paths intersect at this target (focus) point. Considering acoustic waves in a homogeneous medium, we compare travel-time and amplitude measurements extracted from the deep-focusing cross-covariance functions. Using a single-scattering approximation, we find that the spatial sensitivity of deep-focusing travel times to sound-speed perturbations is zero at the target location and maximum in a surrounding shell. This is unlike the deep-focusing amplitude measurements, which have maximum sensitivity at the target point. We compare the signal-to-noise ratio for travel-time and amplitude measurements for different types of sound-speed perturbations, under the assumption that noise is solely due to the random excitation of the waves. We find that, for highly localized perturbations in sound speed, the signal-to-noise ratio is higher for amplitude measurements than for travel-time measurements. We conclude that amplitude measurements are a useful complement to travel-time measurements in time-distance helioseismology.

  15. Heterogeneous Data Fusion Method to Estimate Travel Time Distributions in Congested Road Networks.

    Science.gov (United States)

    Shi, Chaoyang; Chen, Bi Yu; Lam, William H K; Li, Qingquan

    2017-12-06

    Travel times in congested urban road networks are highly stochastic. Provision of travel time distribution information, including both mean and variance, can be very useful for travelers to make reliable path choice decisions to ensure higher probability of on-time arrival. To this end, a heterogeneous data fusion method is proposed to estimate travel time distributions by fusing heterogeneous data from point and interval detectors. In the proposed method, link travel time distributions are first estimated from point detector observations. The travel time distributions of links without point detectors are imputed based on their spatial correlations with links that have point detectors. The estimated link travel time distributions are then fused with path travel time distributions obtained from the interval detectors using Dempster-Shafer evidence theory. Based on fused path travel time distribution, an optimization technique is further introduced to update link travel time distributions and their spatial correlations. A case study was performed using real-world data from Hong Kong and showed that the proposed method obtained accurate and robust estimations of link and path travel time distributions in congested road networks.

  16. Using travel times to simulate multi-dimensional bioreactive transport in time-periodic flows.

    Science.gov (United States)

    Sanz-Prat, Alicia; Lu, Chuanhe; Finkel, Michael; Cirpka, Olaf A

    2016-04-01

    In travel-time models, the spatially explicit description of reactive transport is replaced by associating reactive-species concentrations with the travel time or groundwater age at all locations. These models have been shown adequate for reactive transport in river-bank filtration under steady-state flow conditions. Dynamic hydrological conditions, however, can lead to fluctuations of infiltration velocities, putting the validity of travel-time models into question. In transient flow, the local travel-time distributions change with time. We show that a modified version of travel-time based reactive transport models is valid if only the magnitude of the velocity fluctuates, whereas its spatial orientation remains constant. We simulate nonlinear, one-dimensional, bioreactive transport involving oxygen, nitrate, dissolved organic carbon, aerobic and denitrifying bacteria, considering periodic fluctuations of velocity. These fluctuations make the bioreactive system pulsate: The aerobic zone decreases at times of low velocity and increases at those of high velocity. For the case of diurnal fluctuations, the biomass concentrations cannot follow the hydrological fluctuations and a transition zone containing both aerobic and obligatory denitrifying bacteria is established, whereas a clear separation of the two types of bacteria prevails in the case of seasonal velocity fluctuations. We map the 1-D results to a heterogeneous, two-dimensional domain by means of the mean groundwater age for steady-state flow in both domains. The mapped results are compared to simulation results of spatially explicit, two-dimensional, advective-dispersive-bioreactive transport subject to the same relative fluctuations of velocity as in the one-dimensional model. The agreement between the mapped 1-D and the explicit 2-D results is excellent. We conclude that travel-time models of nonlinear bioreactive transport are adequate in systems of time-periodic flow if the flow direction does not change

  17. The Connected Traveler

    Energy Technology Data Exchange (ETDEWEB)

    Young, Stanley

    2017-04-24

    The Connected Traveler project is a multi-disciplinary undertaking that seeks to validate potential for transformative transportation system energy savings by incentivizing energy efficient travel behavior.

  18. Using prospect theory to investigate the low value of travel time for small time changes

    DEFF Research Database (Denmark)

    Hjorth, Katrine; Fosgerau, Mogens

    : More specifically, whether the phenomenon is generated by preferences being reference-dependent and exhibiting diminishing sensitivity for gains and losses, with a stronger degree of diminishing sensitivity for money than for travel time. We use stated preference data with trade-offs between travel...... time and reference-dependent value functions for time and money, allowing for loss aver- sion and different degrees of diminishing sensitivity for gains and losses. We use semi- parametric local logit estimates of the equi-probability curves in the data to test the model’s appropriateness, and estimate...... its parameters using a mixed logit approach. Our results sup- port the prospect theory explanation....

  19. Time horizon for AFV emission savings under Tier 2

    International Nuclear Information System (INIS)

    Saricks, C. L.

    2000-01-01

    Implementation of the Federal Tier 2 vehicular emission standards according to the schedule presented in the December, 1999 Final Rule will result in substantial reductions of NMHC, CO, NO x , and fine particle emissions from motor vehicles. Currently, when compared to Tier 1 and even NLEV certification requirements, the emissions performance of automobiles and light-duty trucks powered by non-petroleum (especially, gaseous) fuels (i.e., vehicles collectively termed AFVs) enjoy measurable advantage over their gasoline- and diesel-fueled counterparts over the full Federal Test Procedure and, especially, in Bag 1 (cold start). For the lighter end of these vehicle classes, this advantage may disappear shortly after 2004 under the new standards, but should continue for a longer period (perhaps beyond 2008) for the heavier end as well as for heavy-duty vehicles relative to diesel-fueled counterparts. Because of the continuing commitment of the U.S. Department of Energy's Clean Cities coalitions to the acquisition and operation of AFVs of many types and size classes, it is important for them to know in which classes their acquisitions will remain clear relative to the petroleum-fueled counterparts they might otherwise procure. This paper provides an approximate timeline for and expected magnitude of such savings, assuming that full implementation of the Tier 2 standards covering both vehicular emissions and fuel sulfur limits proceeds on schedule. The pollutants of interest are primary ozone precursors and fine particulate matter from fuel combustion

  20. An energy saving mechanism of EPON networks for real time video transmission

    Science.gov (United States)

    Liu, Chien-Ping; Wu, Ho-Ting; Chiang, Yun-Ting; Chien, Shieh-Chieh; Ke, Kai-Wei

    2015-07-01

    Modern access networks are constructed widely by passive optical networks (PONs) to meet the growing bandwidth demand. However, higher bandwidth means more energy consumption. To save energy, a few research works propose the dual-mode energy saving mechanism that allows the ONU to operate between active and sleep modes periodically. However, such dual-mode energy saving design may induce unnecessary power consumption or packet delay increase in the case where only downstream data exist for most of the time. In this paper, we propose a new tri-mode energy saving scheme for Ethernet PON (EPON). The new tri-mode energy saving design, combining the dual-mode saving mechanism with the doze mode, allows the ONU to switch among these three modes alternatively. In the doze mode, the ONU may receive downstream data while keeping its transmitter close. Such scenario is often observed for real time video downstream transmission. Furthermore, the low packet delay of high priority upstream data can be attained through the use of early wake-up mechanism employed in both energy saving modes. The energy saving and system efficiency can thus be achieved jointly while maintaining the differentiated QoS for data with various priorities. Performance results via simulation have demonstrated the effectiveness of such mechanism.

  1. Cognitive mapping in mental time travel and mental space navigation.

    Science.gov (United States)

    Gauthier, Baptiste; van Wassenhove, Virginie

    2016-09-01

    The ability to imagine ourselves in the past, in the future or in different spatial locations suggests that the brain can generate cognitive maps that are independent of the experiential self in the here and now. Using three experiments, we asked to which extent Mental Time Travel (MTT; imagining the self in time) and Mental Space Navigation (MSN; imagining the self in space) shared similar cognitive operations. For this, participants judged the ordinality of real historical events in time and in space with respect to different mental perspectives: for instance, participants mentally projected themselves in Paris in nine years, and judged whether an event occurred before or after, or, east or west, of where they mentally stood. In all three experiments, symbolic distance effects in time and space dimensions were quantified using Reaction Times (RT) and Error Rates (ER). When self-projected, participants were slower and were less accurate (absolute distance effects); participants were also faster and more accurate when the spatial and temporal distances were further away from their mental viewpoint (relative distance effects). These effects show that MTT and MSN require egocentric mapping and that self-projection requires map transformations. Additionally, participants' performance was affected when self-projection was made in one dimension but judgements in another, revealing a competition between temporal and spatial mapping (Experiment 2 & 3). Altogether, our findings suggest that MTT and MSN are separately mapped although they require comparable allo- to ego-centric map conversion. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Using prospect theory to investigate the low marginal value of travel time for small time changes

    DEFF Research Database (Denmark)

    Hjorth, Katrine; Fosgerau, Mogens

    2012-01-01

    that builds on the diminishing or constant sensitivity of the value functions in prospect theory.We use stated preference data with trade-offs between travel time and money that provide separate identification of the degrees of diminishing sensitivity for time and money gains and losses. This enables us...

  3. Travel Times for Screening Mammography: Impact of Geographic Expansion by a Large Academic Health System.

    Science.gov (United States)

    Rosenkrantz, Andrew B; Liang, Yu; Duszak, Richard; Recht, Michael P

    2017-09-01

    This study aims to assess the impact of off-campus facility expansion by a large academic health system on patient travel times for screening mammography. Screening mammograms performed from 2013 to 2015 and associated patient demographics were identified using the NYU Langone Medical Center Enterprise Data Warehouse. During this time, the system's number of mammography facilities increased from 6 to 19, reflecting expansion beyond Manhattan throughout the New York metropolitan region. Geocoding software was used to estimate driving times from patients' homes to imaging facilities. For 147,566 screening mammograms, the mean estimated patient travel time was 19.9 ± 15.2 minutes. With facility expansion, travel times declined significantly (P travel times between such subgroups. However, travel times to pre-expansion facilities remained stable (initial: 26.8 ± 18.9 minutes, final: 26.7 ± 18.6 minutes). Among women undergoing mammography before and after expansion, travel times were shorter for the postexpansion mammogram in only 6.3%, but this rate varied significantly (all P travel burden and reduce travel time variation among sociodemographic populations. Nonetheless, existing patients strongly tend to return to established facilities despite potentially shorter travel time locations, suggesting strong site loyalty. Variation in travel times likely relates to various factors other than facility proximity. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  4. Modelling travel time perception in transport mode choices

    NARCIS (Netherlands)

    Varotto, S.F.; Glerum, A.; Stathopoulos, A.; Bierlaire, M.; Longo, G.

    2015-01-01

    Travel behaviour models typically rely on data afflicted by errors, in perception (e.g., over/under-estimation by traveller) and measurement (e.g., software or researcher imputation error). Such errors are shown to have a relevant impact on model outputs. So far a comprehensive framework to deal

  5. Climatic and landscape controls on travel time distributions across Europe

    Science.gov (United States)

    Kumar, Rohini; Rao, Suresh; Hesse, Falk; Borchardt, Dietrich; Fleckenstein, Jan; Jawitz, James; Musolff, Andreas; Rakovec, Oldrich; Samaniego, Luis; Yang, Soohyun; Zink, Matthias; Attinger, Sabine

    2017-04-01

    Travel time distributions (TTDs) are fundamental descriptors to characterize the functioning of storage, mixing and release of water and solutes in a river basin. Identifying the relative importance (and controls) of climate and landscape attributes on TDDs is fundamental to improve our understanding of the underlying mechanism controlling the spatial heterogeneity of TTDs, and their moments (e.g., mean TT). Studies aimed at elucidating such controls have focused on either theoretical developments to gain (physical) insights using mostly synthetic datasets or empirical relationships using limited datasets from experimental sites. A study painting a general picture of emerging controls at a continental scale is still lacking. In this study, we make use of spatially resolved hydrologic fluxes and states generated through an observationally driven, mesoscale Hydrologic Model (mHM; www.ufz.de/mhm) to comprehensively characterize the dominant controls of climate and landscape attributes on TDDs in the vadose zone across the entire European region. mHM uses a novel Multiscale Parameter Regionalization (MPR; Samaniego et al., 2010 and Kumar et al., 2013) scheme that encapsulates fine scale landscape attributes (e.g., topography, soil, and vegetation characteristics) to account for the sub-grid variability in model parameterization. The model was established at 25 km spatial resolution to simulate the daily gridded fluxes and states over Europe for the period 1955-2015. We utilized recent developments in TTDs theory (e.g., Botter et al., 2010, Harman et al., 2011) to characterize the stationary and non-stationary behavior of water particles transported through the vadose zone at every grid cell. Our results suggest a complex set of interactions between climate and landscape properties controlling the spatial heterogeneity of the mean travel time (TT). The spatial variability in the mean TT across the Pan-EU generally follows the climatic gradient with lower values in humid

  6. Time Traveling Regularization for Inverse Heat Transfer Problems

    Directory of Open Access Journals (Sweden)

    Elisan dos Santos Magalhães

    2018-02-01

    Full Text Available This work presents a technique called Time Traveling Regularization (TTR applied to an optimization technique in order to solve ill-posed problems. This new methodology does not interfere in the minimization technique process. The Golden Section method together with TTR are applied only to the objective function which will be minimized. It consists of finding an ideal timeline that minimizes an objective function in a defined future time step. In order to apply the proposed methodology, inverse heat conduction problems were studied. Controlled experiments were performed on 5052 aluminum and AISI 304 stainless steel samples to validate the proposed technique. One-dimensional and three-dimensional heat input experiments were carried out for the 5052 aluminum and AISI 304 stainless steel samples, respectively. The Sequential Function Specification Method (SFSM was also used to be compared with the results of heat flux obtained by TTR. The estimated heat flux presented a good agreement when compared with experimental values and those estimated by SFSM. Moreover, TTR presented lower residuals than the SFSM.

  7. Time to tighten the belts? Exploring the relationship between savings and obesity

    Science.gov (United States)

    Monahan, Mark; Guariglia, Alessandra; Roberts, Tracy E.

    2017-01-01

    Background Literature suggests that the higher the rate of time preference people have, the less likely they are to save for the future. Likewise, it has been hypothesised that rising rates of being overweight/obesity are associated with an increase in peoples’ marginal rate of time preference. Aim To investigate the relationship between being overweight/ obese and the rate of time preference in an older English population, using savings as a proxy for time preference. Methods Three different econometric methods—Random-effects Probit Estimation, Fixed-effects Estimation, and Generalised Method of Moments Estimation—were used to explore the link between being overweight/ obese and rate of time preference in the English Longitudinal Study of Ageing dataset. Six waves of panel data spanning eleven years provided the data to test whether savings variables are related to being overweight/ obese. Results The decision to save was shown to hold a statistically significant negative relationship with body mass index but only in the Generalised Method of Moments model. Placing savings in safe, low risk investments was significantly related to a lower probability of being obese but only in the random-effects Probit model. The proportion that people saved relative to their income was not found to be significantly associated with the probability of being overweight/ obese in any of the models. Conclusion There is an unclear relationship between saving behaviour and being overweight/ obese in an older English population. A financial variable such as savings is a potentially appropriate but imperfect proxy for the rate of time preference of the population. Further research is required to clarify the relationship in order to help develop strategies for obesity prevention. The inconsistency in the results between methods highlights the importance of using a wide range of alternative techniques before implementing important policy decisions. PMID:28662132

  8. Saving Space and Time: The Tractor That Einstein Built

    Science.gov (United States)

    2006-01-01

    In 1984, NASA initiated the Gravity Probe B (GP-B) program to test two unverified predictions of Albert Einstein s theory of general relativity, hypotheses about the ways space, time, light, and gravity relate to each other. To test these predictions, the Space Agency and researchers at Stanford University developed an experiment that would check, with extreme precision, tiny changes in the spin direction of four gyroscopes contained in an Earth satellite orbiting at a 400-mile altitude directly over the Earth s poles. When the program first began, the researchers assessed using Global Positioning System (GPS) technology to control the attitude of the GP-B spacecraft accurately. At that time, the best GPS receivers could only provide accuracy to nearly 1 meter, but the GP-B spacecraft required a system 100 times more accurate. To address this concern, researchers at Stanford designed high-performance, attitude-determining hardware that used GPS signals, perfecting a high-precision form of GPS called Carrier-Phase Differential GPS that could provide continuous real-time position, velocity, time, and attitude sensor information for all axes of a vehicle. The researchers came to the realization that controlling the GP-B spacecraft with this new system was essentially no different than controlling an airplane. Their thinking took a new direction: If this technology proved successful, the airlines and the Federal Aviation Administration (FAA) were ready commercial markets. They set out to test the new technology, the "Integrity Beacon Landing System," using it to automatically land a commercial Boeing 737 over 100 times successfully through Real-Time Kinematic (RTK) GPS technology. The thinking of the researchers shifted again, from automatically landing aircraft, to automating precision farming and construction equipment.

  9. Daylight-saving time: Consumption and demand saving and pollutants emission reduction; El cambio de horario de verano: Ahorros en consumo y demanda, y reduccion de contaminantes

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, Gaudencio; Diaz, Rodrigo; Fiscal, Raul; Alquicira, Claudia; Martinez, Serafin; Maqueda, Martin [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1997-12-31

    This paper presents some of the saving obtained in demand and in fuels with the daylight-saving time, as well as the main aspects considered to make an evaluation of it. [Espanol] Se presentan los ahorros obtenidos en consumo, demanda y combustibles con el cambio de horario de verano, asi como los principales aspectos considerados para efectuar la evaluacion de los mismos.

  10. The impact of travel distance, travel time and waiting time on health-related quality of life of diabetes patients: An investigation in six European countries.

    Science.gov (United States)

    Konerding, Uwe; Bowen, Tom; Elkhuizen, Sylvia G; Faubel, Raquel; Forte, Paul; Karampli, Eleftheria; Mahdavi, Mahdi; Malmström, Tomi; Pavi, Elpida; Torkki, Paulus

    2017-04-01

    The effects of travel distance and travel time to the primary diabetes care provider and waiting time in the practice on health-related quality of life (HRQoL) of patients with type 2 diabetes are investigated. Survey data of 1313 persons with type 2 diabetes from six regions in England (274), Finland (163), Germany (254), Greece (165), the Netherlands (354), and Spain (103) were analyzed. Various multiple linear regression analyses with four different EQ-5D-3L indices (English, German, Dutch and Spanish index) as target variables, with travel distance, travel time, and waiting time in the practice as focal predictors and with control for study region, patient's gender, patient's age, patient's education, time since diagnosis, thoroughness of provider-patient communication were computed. Interactions of regions with the remaining five control variables and the three focal predictors were also tested. There are no interactions of regions with control variables or focal predictors. The indices decrease with increasing travel time to the provider and increasing waiting time in the provider's practice. HRQoL of patients with type 2 diabetes might be improved by decreasing travel time to the provider and waiting time in the provider's practice. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Application of travel time information for traffic management : technical summary.

    Science.gov (United States)

    2012-01-01

    Using conventional methods, it is extremely costly to measure detailed traffic characteristics in high quality spatial or temporal resolution. For analyzing travel characteristics on roadways, the floating car method, developed in the 1920s, has hist...

  12. Recent developments in guided wave travel time tomography

    Energy Technology Data Exchange (ETDEWEB)

    Zon, Tim van; Volker, Arno [TNO, Stieltjesweg 1, P.O. box 155 2600 AD Delft (Netherlands)

    2014-02-18

    The concept of predictive maintenance using permanent sensors that monitor the integrity of an installation is an interesting addition to the current method of periodic inspections. Guided wave tomography had been developed to create a map of the wall thickness using the travel times of guided waves. It can be used for both monitoring and for inspection of pipe-segments that are difficult to access, for instance at the location of pipe-supports. An important outcome of the tomography is the minimum remaining wall thickness, as this is critical in the scheduling of a replacement of the pipe-segment. In order to improve the sizing accuracy we have improved the tomography scheme. A number of major improvements have been realized allowing to extend the application envelope to pipes with a larger wall thickness and to larger distances between the transducer rings. Simulation results indicate that the sizing accuracy has improved and that is now possible to have a spacing of 8 meter between the source-ring and the receiver-ring. Additionally a reduction of the number of sensors required might be possible as well.

  13. Travel time seismic tomography on Reykjanes, SW Iceland

    Science.gov (United States)

    Jousset, Philippe; Ágústsson, Kristjan; Blanck, Hanna; Metz, Malte; Franke, Steven; Pàll Hersir, Gylfi; Bruhn, David; Flovenz, Ólafur; Friðleifsson, Guðmundur

    2017-04-01

    We present updated tomographic results obtained using seismic data recorded around geothermal reservoirs located both on-land Reykjanes, SW-Iceland and offshore along Reykjanes Ridge. We gathered records from a network of 234 seismic stations (including 24 Ocean Bottom Seismometers) deployed between April 2014 and August 2015. In order to determine the orientation of the OBS stations, we used Rayleigh waves planar particle motions from large magnitude earthquakes. This method proved suitable using the on-land stations: orientations determined using this method with the orientations measured using a giro-compass agreed. We focus on the 3D velocity images using local earthquakes to perform travel time tomography. The processing includes first arrival picking of P- and S- phases using an automatic detection and picking technique based on Akaike Information Criteria. We locate earthquakes by using a non-linear localization technique, as a priori information for deriving a 1D velocity model. We then computed 3D velocity model by joint inversion of each earthquake's location and velocity lateral anomalies with respect to the 1D model. Our models confirms previous models obtained in the area, with enhanced details. In a second step, we performed inversion of the Vp/Vs ratio. Results indicate a low Vp/Vs ratio anomaly at depth suggesting the absence of large magmatic body under Reykjanes, unlike results obtained at other geothermal field, sucha as Krafla and Hengill. We discuss implications of those results in the light of recent IDDP drilling in Reykjanes.

  14. Iterative Bayesian Estimation of Travel Times on Urban Arterials: Fusing Loop Detector and Probe Vehicle Data.

    Science.gov (United States)

    Liu, Kai; Cui, Meng-Ying; Cao, Peng; Wang, Jiang-Bo

    2016-01-01

    On urban arterials, travel time estimation is challenging especially from various data sources. Typically, fusing loop detector data and probe vehicle data to estimate travel time is a troublesome issue while considering the data issue of uncertain, imprecise and even conflicting. In this paper, we propose an improved data fusing methodology for link travel time estimation. Link travel times are simultaneously pre-estimated using loop detector data and probe vehicle data, based on which Bayesian fusion is then applied to fuse the estimated travel times. Next, Iterative Bayesian estimation is proposed to improve Bayesian fusion by incorporating two strategies: 1) substitution strategy which replaces the lower accurate travel time estimation from one sensor with the current fused travel time; and 2) specially-designed conditions for convergence which restrict the estimated travel time in a reasonable range. The estimation results show that, the proposed method outperforms probe vehicle data based method, loop detector based method and single Bayesian fusion, and the mean absolute percentage error is reduced to 4.8%. Additionally, iterative Bayesian estimation performs better for lighter traffic flows when the variability of travel time is practically higher than other periods.

  15. Travel Time Estimation and Prediction using Mobile Phones: A Cost Effective Method for Developing Countries

    Directory of Open Access Journals (Sweden)

    Satyakumar, M.

    2014-01-01

    Full Text Available Conventional data collection methods lack real time information and involve excessive cost of installation and maintenance. A real-time, low cost travel time data collection system can be developed using mobile phones. This project examines the use of mobile phones for travel time prediction of public transit vehicles and develops a dynamic travel time prediction model. Personnel were employed in public transit vehicles with mobile phones and these mobile phones were tracked continuously. Space information of the mobile phones represents the position of the buses and movement pattern of these mobile phones in turn represents the movement pattern of the public buses. The starting and arrival time at sections obtained from the cellular database were used to get the travel time and speed. Results obtained were statistically significant and it shows that use of mobile phone for travel time data collection is a low cost data collection technique for Indian cities.

  16. Rural population travel time to health services, mapped on Geographic Information System (GIS

    Directory of Open Access Journals (Sweden)

    Ricardo Vicente Ferreira

    2014-04-01

    Full Text Available Distance and travel time are important parameters in the evaluation of access to health services, especially for the population living in the countryside. In the present work, a GIS-based methodology is developed for the mapping of rural road networks and the determination of travel impedances in order to optimize the travel time of the rural population to health care facilities. Data on rural roads classes, slope, sinuosity, visibility and land use are considered in the composition of the impedances synthesis and its application on car travel time. The methodology was applied to the region of Registro (SP, and the results indicate an unequal distribution of health services.

  17. Numerical modeling for saturated-zone groundwater travel time analysis at Yucca Mountain

    International Nuclear Information System (INIS)

    Arnold, B.W.; Barr, G.E.

    1996-01-01

    A three-dimensional, site-scale numerical model of groundwater flow in the saturated zone at Yucca Mountain was constructed and linked to particle tracking simulations to produce an estimate of the distribution of groundwater travel times from the potential repository to the boundary of the accessible environment. This effort and associated modeling of groundwater travel times in the unsaturated zone were undertaken to aid in the evaluation of compliance of the site with 10CFR960. These regulations stipulate that pre-waste-emplacement groundwater travel time to the accessible environment shall exceed 1,000 years along any path of likely and significant radionuclide travel

  18. Efficacy of New Measures Saving Time in Acute Stroke Management: A Quantified Analysis.

    Science.gov (United States)

    Iglesias Mohedano, Ana María; García Pastor, Andrés; Díaz Otero, Fernando; Vázquez Alen, Pilar; Vales Montero, Marta; Luque Buzo, Elisa; Redondo Ráfales, Nuria; Chavarria Cano, Beatriz; Fernández Bullido, Yolanda; Villanueva Osorio, Jose Antonio; Gil Núñez, Antonio

    2017-08-01

    Time to treatment remains the most important factor in acute ischemic stroke prognosis. We quantified the effect of new interventions reducing in-hospital delays in acute stroke management and assessed its repercussion on door-to-imaging (DTI), imaging-to-needle (ITN), and door-to-needle (DTN) times. Prospective registry of consecutive stroke patients who were candidates for reperfusion therapy attended in a tertiary care hospital from February 1 to December 31, 2014. A series of measures aimed at reducing in-hospital delays were implemented. We compared DTI, ITN, and DTN times between patients who underwent the interventions and those who did not. 231 patients. DTI time was lower when personal history was reviewed and tests were ordered before patient arrival (2.5 minutes saved, P = .016) and when electrocardiogram was not made (5.4 minutes saved, P time significantly (14 and 12 minutes saved, respectively, P time. Completing all steps resulted in the lowest DTI and ITN times (13 and 19 minutes, respectively). Every measure is an important part of a chain focused on saving time in acute stroke: the lowest DTI and ITN times were obtained when all steps were completed. Measures shortening ITN time produced a greater impact on DTN time reduction; therefore, ITN interventions should be considered a critical part of new protocols and guidelines. Copyright © 2017. Published by Elsevier Inc.

  19. Daylight saving time transitions and hospital treatments due to accidents or manic episodes.

    Science.gov (United States)

    Lahti, Tuuli A; Haukka, Jari; Lönnqvist, Jouko; Partonen, Timo

    2008-02-26

    Daylight saving time affects millions of people annually but its impacts are still widely unknown. Sleep deprivation and the change of circadian rhythm can trigger mental illness and cause higher accident rates. Transitions into and out of daylight saving time changes the circadian rhythm and may cause sleep deprivation. Thus it seems plausible that the prevalence of accidents and/or manic episodes may be higher after transition into and out of daylight saving time. The aim of this study was to explore the effects of transitions into and out of daylight saving time on the incidence of accidents and manic episodes in the Finnish population during the years of 1987 to 2003. The nationwide data were derived from the Finnish Hospital Discharge Register. From the register we obtained the information about the hospital-treated accidents and manic episodes during two weeks before and two weeks after the transitions in 1987-2003. The results were negative, as the transitions into or out of daylight saving time had no significant effect on the incidence of accidents or manic episodes. One-hour transitions do not increase the incidence of manic episodes or accidents which require hospital treatment.

  20. Daylight saving time transitions and hospital treatments due to accidents or manic episodes

    Directory of Open Access Journals (Sweden)

    Lönnqvist Jouko

    2008-02-01

    Full Text Available Abstract Background Daylight saving time affects millions of people annually but its impacts are still widely unknown. Sleep deprivation and the change of circadian rhythm can trigger mental illness and cause higher accident rates. Transitions into and out of daylight saving time changes the circadian rhythm and may cause sleep deprivation. Thus it seems plausible that the prevalence of accidents and/or manic episodes may be higher after transition into and out of daylight saving time. The aim of this study was to explore the effects of transitions into and out of daylight saving time on the incidence of accidents and manic episodes in the Finnish population during the years of 1987 to 2003. Methods The nationwide data were derived from the Finnish Hospital Discharge Register. From the register we obtained the information about the hospital-treated accidents and manic episodes during two weeks before and two weeks after the transitions in 1987–2003. Results The results were negative, as the transitions into or out of daylight saving time had no significant effect on the incidence of accidents or manic episodes. Conclusion One-hour transitions do not increase the incidence of manic episodes or accidents which require hospital treatment.

  1. Daylight saving time transitions and hospital treatments due to accidents or manic episodes

    Science.gov (United States)

    Lahti, Tuuli A; Haukka, Jari; Lönnqvist, Jouko; Partonen, Timo

    2008-01-01

    Background Daylight saving time affects millions of people annually but its impacts are still widely unknown. Sleep deprivation and the change of circadian rhythm can trigger mental illness and cause higher accident rates. Transitions into and out of daylight saving time changes the circadian rhythm and may cause sleep deprivation. Thus it seems plausible that the prevalence of accidents and/or manic episodes may be higher after transition into and out of daylight saving time. The aim of this study was to explore the effects of transitions into and out of daylight saving time on the incidence of accidents and manic episodes in the Finnish population during the years of 1987 to 2003. Methods The nationwide data were derived from the Finnish Hospital Discharge Register. From the register we obtained the information about the hospital-treated accidents and manic episodes during two weeks before and two weeks after the transitions in 1987–2003. Results The results were negative, as the transitions into or out of daylight saving time had no significant effect on the incidence of accidents or manic episodes. Conclusion One-hour transitions do not increase the incidence of manic episodes or accidents which require hospital treatment. PMID:18302734

  2. Chapter 10: Peak Demand and Time-Differentiated Energy Savings Cross-Cutting Protocol. The Uniform Methods Project: Methods for Determining Energy Efficiency Savings for Specific Measures

    Energy Technology Data Exchange (ETDEWEB)

    Kurnik, Charles W [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Stern, Frank [Navigant, Boulder, CO (United States); Spencer, Justin [Navigant, Boulder, CO (United States)

    2017-10-03

    Savings from electric energy efficiency measures and programs are often expressed in terms of annual energy and presented as kilowatt-hours per year (kWh/year). However, for a full assessment of the value of these savings, it is usually necessary to consider the measure or program's impact on peak demand as well as time-differentiated energy savings. This cross-cutting protocol describes methods for estimating the peak demand and time-differentiated energy impacts of measures implemented through energy efficiency programs.

  3. Energy conservation: policy issues and end-use scenarios of savings potential. Part IV. Energy-efficient recreational travel

    Energy Technology Data Exchange (ETDEWEB)

    Benson, P.; Codina, R.; Cornwall, B.

    1978-09-01

    The guidelines laid out for the five subjects investigated in this series are to take a holistic view of energy conservation policies by describing the overall system in which they are implemented; provide analytical tools and sufficiently disaggregated data bases that can be adapted to answer a variety of questions by the users; identify and discuss some of the important issues behind successful energy conservation policy; and develop an energy conservation policy in depth. This report contains the design of a specific policy that addresses energy conservation in recreational travel. The policy is denoted as an ''Information System for the National Park Service.'' This work is based on prior examination of the characteristics of the recreational trip and decision making for the recreational experience. The examination revealed which aspects of the recreational travel system needed to be addressed to encourage energy-efficient modal decisions for recreational travel. This policy is briefly described in Section 1, the ''Summary of Initiative.'' A more detailed discussion of the policy follows. The material which led to the policy's formation is developed in Section 2: Importance and Impact of the Recreational Trip; Weekend Travel; The Flowchart: Decision Making for the Recreational Experience; Policy Development for Phase 1 ''Planning the Trip;'' and Objectives and Strategies for ''Planning the Trip.'' (MCW)

  4. Time travel and warp drives a scientific guide to shortcuts through time and space

    CERN Document Server

    Everett, Allen

    2012-01-01

    Sci-fi makes it look so easy. Receive a distress call from Alpha Centauri? No problem: punch the warp drive and you're there in minutes. Facing a catastrophe that can't be averted? Just pop back in the timestream and stop it before it starts. But for those of us not lucky enough to live in a science-fictional universe, are these ideas merely flights of fancy—or could it really be possible to travel through time or take shortcuts between stars?Cutting-edge physics may not be able to answer those questions yet, but it does offer up some tantalizing possibilities. In Time Travel and W

  5. A method for generating an illusion of backwards time travel using immersive virtual reality—an exploratory study

    Science.gov (United States)

    Friedman, Doron; Pizarro, Rodrigo; Or-Berkers, Keren; Neyret, Solène; Pan, Xueni; Slater, Mel

    2014-01-01

    We introduce a new method, based on immersive virtual reality (IVR), to give people the illusion of having traveled backwards through time to relive a sequence of events in which they can intervene and change history. The participant had played an important part in events with a tragic outcome—deaths of strangers—by having to choose between saving 5 people or 1. We consider whether the ability to go back through time, and intervene, to possibly avoid all deaths, has an impact on how the participant views such moral dilemmas, and also whether this experience leads to a re-evaluation of past unfortunate events in their own lives. We carried out an exploratory study where in the “Time Travel” condition 16 participants relived these events three times, seeing incarnations of their past selves carrying out the actions that they had previously carried out. In a “Repetition” condition another 16 participants replayed the same situation three times, without any notion of time travel. Our results suggest that those in the Time Travel condition did achieve an illusion of “time travel” provided that they also experienced an illusion of presence in the virtual environment, body ownership, and agency over the virtual body that substituted their own. Time travel produced an increase in guilt feelings about the events that had occurred, and an increase in support of utilitarian behavior as the solution to the moral dilemma. Time travel also produced an increase in implicit morality as judged by an implicit association test. The time travel illusion was associated with a reduction of regret associated with bad decisions in their own lives. The results show that when participants have a third action that they can take to solve the moral dilemma (that does not immediately involve choosing between the 1 and the 5) then they tend to take this option, even though it is useless in solving the dilemma, and actually results in the deaths of a greater number. PMID:25228889

  6. A method for generating an illusion of backwards time travel using immersive virtual reality - an exploratory study

    Directory of Open Access Journals (Sweden)

    Doron eFriedman

    2014-09-01

    Full Text Available We introduce a new method, based on immersive virtual reality, to give people the illusion of having travelled backwards through time to relive a sequence of events in which they can intervene and change history. The participant had played an important part in events with a tragic outcome - deaths of strangers – by having to choose between saving 5 people or 1. We consider whether the ability to go back through time, and intervene, to possibly avoid all deaths, has an impact on how the participant views such moral dilemmas, and also whether this experience leads to a re-evaluation of past unfortunate events in their own lives. We carried out an exploratory study where in the ‘Time Travel’ condition 16 participants relived these events three times, seeing incarnations of their past selves carrying out the actions that they had previously carried out. In a ‘Repetition’ condition another 16 participants replayed the same situation three times, without any notion of time travel. Our results suggest that those in the Time Travel condition did achieve an illusion of ‘time travel’ provided that they also experienced an illusion of presence in the virtual environment, body ownership and agency over the virtual body that substituted their own. Time travel produced an increase in guilt feelings about the events that had occurred, and an increase in support of utilitarian behavior as the solution to the moral dilemma. Time travel also produced an increase in implicit morality as judged by an implicit association test. The time travel illusion was associated with a reduction of regret associated with bad decisions in their own lives. The results show that when participants have a third action that they can take to solve the moral dilemma (that does not immediately involve choosing between the 1 and the 5 then they tend to take this option, even though it is useless in solving the dilemma, and actually results in the deaths of a greater number.

  7. Travelling Solitary Wave Solutions for Generalized Time-delayed Burgers-Fisher Equation

    International Nuclear Information System (INIS)

    Deng Xijun; Han Libo; Li Xi

    2009-01-01

    In this paper, travelling wave solutions for the generalized time-delayed Burgers-Fisher equation are studied. By using the first-integral method, which is based on the ring theory of commutative algebra, we obtain a class of travelling solitary wave solutions for the generalized time-delayed Burgers-Fisher equation. A minor error in the previous article is clarified. (general)

  8. Toward a formal foundation for time travel in stories and games

    NARCIS (Netherlands)

    M. Helvensteijn (Michiel); F. Arbab (Farhad)

    2016-01-01

    textabstractTime-travel is a popular topic not only in science fiction, but in physics as well, especially when it concerns the notion of “changing the past”. It turns out that if time-travel exists, it will follow certain logical rules. In this paper we apply the tools of discrete mathematics to

  9. Approaching the Brachistochrone Using Inclined Planes--Striving for Shortest or Equal Travelling Times

    Science.gov (United States)

    Theilmann, Florian

    2017-01-01

    The classical "brachistochrone" problem asks for the path on which a mobile point M just driven by its own gravity will travel in the shortest possible time between two given points "A" and "B." The resulting curve, the cycloid, will also be the "tautochrone" curve, i.e. the travelling time of the mobile…

  10. Does Involuntary Mental Time Travel Make Sense in Prospective Teachers' Feelings and Behaviors during Lessons?

    Science.gov (United States)

    Eren, Altay; Yesilbursa, Amanda

    2013-01-01

    This study examined the effects of involuntary mental time travel into the past and into the future on prospective teachers' feelings and behaviors during the period of a class hour. A total of 110 prospective teachers participated voluntarily in the study. The results of the present study showed that (a) the involuntary mental time travel into…

  11. A Simplified Network Model for Travel Time Reliability Analysis in a Road Network

    Directory of Open Access Journals (Sweden)

    Kenetsu Uchida

    2017-01-01

    Full Text Available This paper proposes a simplified network model which analyzes travel time reliability in a road network. A risk-averse driver is assumed in the simplified model. The risk-averse driver chooses a path by taking into account both a path travel time variance and a mean path travel time. The uncertainty addressed in this model is that of traffic flows (i.e., stochastic demand flows. In the simplified network model, the path travel time variance is not calculated by considering all travel time covariance between two links in the network. The path travel time variance is calculated by considering all travel time covariance between two adjacent links in the network. Numerical experiments are carried out to illustrate the applicability and validity of the proposed model. The experiments introduce the path choice behavior of a risk-neutral driver and several types of risk-averse drivers. It is shown that the mean link flows calculated by introducing the risk-neutral driver differ as a whole from those calculated by introducing several types of risk-averse drivers. It is also shown that the mean link flows calculated by the simplified network model are almost the same as the flows calculated by using the exact path travel time variance.

  12. Self-Efficacy Beliefs and Mental Time Travel Ability: Uncovering a Hidden Relationship in Educational Settings

    Science.gov (United States)

    Eren, Altay

    2009-01-01

    The aim of this study was threefold: first, it was to explore the profiles of student teachers' mental time travel ability; second, it was to examine the relationship between student teachers' mental time travel ability and self-efficacy beliefs; and third, it was to investigate the role of self-efficacy beliefs in relationship between the past…

  13. Making Decisions with the Future in Mind: Developmental and Comparative Identification of Mental Time Travel

    Science.gov (United States)

    Suddendorf, T.; Busby, J.

    2005-01-01

    Mechanisms that produce behavior which increase future survival chances provide an adaptive advantage. The flexibility of human behavior is at least partly the result of one such mechanism, our ability to travel mentally in time and entertain potential future scenarios. We can study mental time travel in children using language. Current results…

  14. Mental time travel : A conceptual overview of social psychological perspectives on a fundamental human capacity

    NARCIS (Netherlands)

    Epstude, K.; Peetz, J.

    Humans have the unique capacity to mentally travel through time, that is, to reflect on the past, anticipate the future, and construct alternate realities in their minds. The ability to mentally travel through time affects a variety of social psychological topics. Representations of events can

  15. The human circadian clock's seasonal adjustment is disrupted by daylight saving time

    NARCIS (Netherlands)

    Kantermann, Thomas; Juda, Myriam; Merrow, Martha; Roenneberg, Till

    2007-01-01

    A quarter of the world's population is subjected to a 1 hr time change twice a year (daylight saving time, DST). This reflects a change in social clocks, not environmental ones (e.g., dawn). The impact of DST is poorly understood. Circadian clocks use daylight to synchronize (entrain) to the

  16. Complexity in the validation of ground-water travel time in fractured flow and transport systems

    International Nuclear Information System (INIS)

    Davies, P.B; Hunter, R.L.; Pickens, J.F.

    1991-02-01

    Ground-water travel time is a widely used concept in site assessment for radioactive waste disposal. While ground-water travel time was originally conceived to provide a simple performance measure for evaluating repository sites, its definition in many flow and transport environments is ambiguous. The US Department of Energy siting guidelines (10 CFR 960) define ground-water travel time as the time required for a unit volume of water to travel between two locations, calculated by dividing travel-path length by the quotient of average ground-water flux and effective porosity. Defining a meaningful effective porosity in a fractured porous material is a significant problem. Although the Waste Isolation Pilot Plant (WIPP) is not subject to specific requirements for ground-water travel time, travel times have been computed under a variety of model assumptions. Recently completed model analyses for WIPP illustrate the difficulties in applying a ground-water travel-time performance measure to flow and transport in fractured, fully saturated flow systems. 12 refs., 4 figs

  17. Complexity in the validation of ground-water travel time in fractured flow and transport systems

    International Nuclear Information System (INIS)

    Davies, P.B.; Hunter, R.L.; Pickens, J.F.

    1991-01-01

    Ground-water travel time is a widely used concept in site assessment for radioactive waste disposal. While ground-water travel time was originally conceived to provide a simple performance measure for evaluating repository sites, its definition in many flow and transport environments is ambiguous. The U.S. Department of Energy siting guidelines (10 CFR 960) define ground-water travel time as the time required for a unit volume of water to travel between two locations, calculated by dividing travel-path length by the quotient of average ground-water flux and effective porosity. Defining a meaningful effective porosity in a fractured porous material is a significant problem. Although the Waste Isolation Pilot Plant (WIPP) is not subject to specific requirements for ground-water travel time, travel times have been computed under a variety of model assumptions. Recently completed model analyses for WIPP illustrate the difficulties in applying a ground-water travel-time performance measure to flow and transport in fractured, fully saturated flow systems. Computer code used: SWIFT II (flow and transport code). 4 figs., 12 refs

  18. The impact of travel time on geographic distribution of dialysis patients.

    Science.gov (United States)

    Kashima, Saori; Matsumoto, Masatoshi; Ogawa, Takahiko; Eboshida, Akira; Takeuchi, Keisuke

    2012-01-01

    The geographic disparity of prevalence rates among dialysis patients is unclear. We evaluate the association between travel time to dialysis facilities and prevalence rates of dialysis patients living in 1,867 census areas of Hiroshima, Japan. Furthermore, we study the effects of geographic features (mainland or island) on the prevalence rates and assess if these effects modify the association between travel time and prevalence. The study subjects were all 7,374 people that were certified as the "renal disabled" by local governments in 2011. The travel time from each patient to the nearest available dialysis facility was calculated by incorporating both travel time and the capacity of all 98 facilities. The effect of travel time on the age- and sex-adjusted standard prevalence rate (SPR) and 95% confidence intervals (CIs) at each census area was evaluated in two-level Poisson regression models with 1,867 census areas (level 1) nested within 35 towns or cities (level 2). The results were adjusted for area-based parameters of socioeconomic status, urbanity, and land type. Furthermore, the SPR of dialysis patients was calculated in each specific subgroup of population for travel time, land type, and combination of land type and travel time. In the regression analysis, SPR decreased by 5.2% (95% CI: -7.9--2.3) per 10-min increase in travel time even after adjusting for potential confounders. The effect of travel time on prevalence was different in the mainland and island groups. There was no travel time-dependent SPR disparity on the islands. The SPR among remote residents (>30 min from facilities) in the mainland was lower (0.77, 95% CI: 0.71-0.85) than that of closer residents (≤ 30 min; 0.95, 95% CI: 0.92-0.97). The prevalence of dialysis patients was lower among remote residents. Geographic difficulties for commuting seem to decrease the prevalence rate.

  19. A Study on the Optimal Duration of Daylight Saving Time (DST in Korea

    Directory of Open Access Journals (Sweden)

    Byeong-Hee Mihn

    2009-09-01

    Full Text Available Daylight saving time aims at spending effective daylight in summer season. Korea had enforced daylight saving time twelve times from 1948 to 1988. Since 1988, it is not executed, but it is recently discussed the resumption of DST. In this paper, we investigate the trend of DST in other countries, review the history of DST in Korea, and suggest the optimal DST duration in terms of astronomical aspects (times of sunrise and sunset. We find that the starting day of DST in Korea is apt for the second Sunday in Mayor the second Sunday in April according to the time of sunrise or to the difference between Korean standard meridian and observer`s, respectively. We also discuss time friction that might be caused by time difference between DST and Korea Standard Time (KST.

  20. Prospective and retrospective time perception are related to mental time travel: evidence from Alzheimer's disease.

    Science.gov (United States)

    El Haj, Mohamad; Moroni, Christine; Samson, Séverine; Fasotti, Luciano; Allain, Philippe

    2013-10-01

    Unlike prospective time perception paradigms, in which participants are aware that they have to estimate forthcoming time, little is known about retrospective time perception in normal aging and Alzheimer's disease (AD). Our paper addresses this shortcoming by comparing prospective and retrospective time estimation in younger adults, older adults, and AD patients. In four prospective tasks (lasting 30s, 60s, 90s, or 120s) participants were asked to read a series of numbers and to provide a verbal estimation of the reading time. In four other retrospective tasks, they were not informed about time judgment until they were asked to provide a verbal estimation of four elapsed time intervals (lasting 30s, 60s, 90s, or 120s). AD participants gave shorter verbal time estimations than older adults and younger participants did, suggesting that time is perceived to pass quickly in these patients. For all participants, the duration of the retrospective tasks was underestimated as compared to the prospective tasks and both estimations were shorter than the real time interval. Prospective time estimation was further correlated with mental time travel, as measured with the Remember/Know paradigm. Mental time travel was even higher correlated with retrospective time estimation. Our findings shed light on the relationship between time perception and the ability to mentally project oneself into time, two skills contributing to human memory functioning. Finally, time perception deficits, as observed in AD patients, can be interpreted in terms of dramatic changes occurring in frontal lobes and hippocampus. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. Highway travel time information system based on cumulative count curves and new tracking technologies

    Energy Technology Data Exchange (ETDEWEB)

    Soriguera Marti, F.; Martinez-Diaz, M.; Perez Perez, I.

    2016-07-01

    Travel time is probably the most important indicator of the level of service of a highway, and it is also the most appreciated information for its users. Administrations and private companies make increasing efforts to improve its real time estimation. The appearance of new technologies makes the precise measurement of travel times easier than never before. However, direct measurements of travel time are, by nature, outdated in real time, and lack of the desired forecasting capabilities. This paper introduces a new methodology to improve the real time estimation of travel times by using the equipment usually present in most highways, i.e., loop detectors, in combination with Automatic Vehicle Identification or Tracking Technologies. One of the most important features of the method is the usage of cumulative counts at detectors as an input, avoiding the drawbacks of common spot-speed methodologies. Cumulative count curves have great potential for freeway travel time information systems, as they provide spatial measurements and thus allow the calculation of instantaneous travel times. In addition, they exhibit predictive capabilities. Nevertheless, they have not been used extensively mainly because of the error introduced by the accumulation of the detector drift. The proposed methodology solves this problem by correcting the deviations using direct travel time measurements. The method results highly beneficial for its accuracy as well as for its low implementation cost. (Author)

  2. Value of travel-time reliability : commuters' route-choice behavior in the Twin Cities.

    Science.gov (United States)

    2011-10-01

    Travel-time variability is a noteworthy factor in network performance. It measures the temporal uncertainty experienced by users in their : movement between any two nodes in a network. The importance of the time variance depends on the penalties incu...

  3. Parsimonious wave-equation travel-time inversion for refraction waves

    KAUST Repository

    Fu, Lei

    2017-02-14

    We present a parsimonious wave-equation travel-time inversion technique for refraction waves. A dense virtual refraction dataset can be generated from just two reciprocal shot gathers for the sources at the endpoints of the survey line, with N geophones evenly deployed along the line. These two reciprocal shots contain approximately 2N refraction travel times, which can be spawned into O(N2) refraction travel times by an interferometric transformation. Then, these virtual refraction travel times are used with a source wavelet to create N virtual refraction shot gathers, which are the input data for wave-equation travel-time inversion. Numerical results show that the parsimonious wave-equation travel-time tomogram has about the same accuracy as the tomogram computed by standard wave-equation travel-time inversion. The most significant benefit is that a reciprocal survey is far less time consuming than the standard refraction survey where a source is excited at each geophone location.

  4. Tuberculin skin test reactions by time of reading among Dutch travellers

    NARCIS (Netherlands)

    Cobelens, F.; van Deutekom, H.; Draayer-Jansen, I.; Schepp-Beelen, A.; van Gerven, P.; Mensen, M.

    2003-01-01

    Five travel and TB control clinics in The Netherlands. To assess the variation of skin test reactions between different days of reading. Cohort study of non-BCG-vaccinated travellers. Mantoux skin test data were analysed for associations between time interval between administration and reading and

  5. Behavioural decisions of travel-time ratios for work, maintenance and leisure activities in the Netherlands.

    NARCIS (Netherlands)

    Susilo, Y.S.; Dijst, M.J.

    2010-01-01

    Using the 2005 Dutch National Travel Survey data-set this paper investigates the influences of socio-demographics, journey patterns and built environment factors on the ratio of travel time and activity duration that an individual spends when engaging in work, daily shopping, non-daily shopping

  6. Daylight Savings Time Transitions and the Incidence Rate of Unipolar Depressive Episodes

    DEFF Research Database (Denmark)

    Hansen, Bertel Teilfeldt; Sønderskov, Kim Mannemar; Hageman, Ida

    2017-01-01

    : Using time series intervention analysis of nationwide data from the Danish Psychiatric Central Research Register from 1995 to 2012, we compared the observed trend in the incidence rate of hospital contacts for unipolar depressive episodes after the transitions to and from summer time to the predicted...... trend in the incidence rate. Results: The analyses were based on 185,419 hospital contacts for unipolar depression and showed that the transition from summer time to standard time were associated with an 11% increase (95% CI = 7%, 15%) in the incidence rate of unipolar depressive episodes......Background: Daylight savings time transitions affect approximately 1.6 billion people worldwide. Prior studies have documented associations between daylight savings time transitions and adverse health outcomes, but it remains unknown whether they also cause an increase in the incidence rate...

  7. Household Consumption and Savings Around the Time of Births and the Role of Education

    NARCIS (Netherlands)

    Kalwij, A.S.

    2003-01-01

    This study examines households’ financial situation around the time of births using a panel of Dutch households over the period 1987-1993. I find that at all levels of education households accumulate wealth before and draw on their liquid savings after having given birth to their first child.

  8. Household consumption and savings around the time of births and the role of education.

    NARCIS (Netherlands)

    Kalwij, A.S.

    2003-01-01

    This study examines households’ financial situation around the time of births using a panel of Dutch households over the period 1987-1993. I find that at all levels of education households accumulate wealth before and draw on their liquid savings after having given birth to their first child.

  9. Daylight Savings Time Transitions and the Incidence Rate of Unipolar Depressive Episodes.

    Science.gov (United States)

    Hansen, Bertel T; Sønderskov, Kim M; Hageman, Ida; Dinesen, Peter T; Østergaard, Søren D

    2017-05-01

    Daylight savings time transitions affect approximately 1.6 billion people worldwide. Prior studies have documented associations between daylight savings time transitions and adverse health outcomes, but it remains unknown whether they also cause an increase in the incidence rate of depressive episodes. This seems likely because daylight savings time transitions affect circadian rhythms, which are implicated in the etiology of depressive disorder. Therefore, we investigated the effects of daylight savings time transitions on the incidence rate of unipolar depressive episodes. Using time series intervention analysis of nationwide data from the Danish Psychiatric Central Research Register from 1995 to 2012, we compared the observed trend in the incidence rate of hospital contacts for unipolar depressive episodes after the transitions to and from summer time to the predicted trend in the incidence rate. The analyses were based on 185,419 hospital contacts for unipolar depression and showed that the transition from summer time to standard time were associated with an 11% increase (95% CI = 7%, 15%) in the incidence rate of unipolar depressive episodes that dissipated over approximately 10 weeks. The transition from standard time to summer time was not associated with a parallel change in the incidence rate of unipolar depressive episodes. This study shows that the transition from summer time to standard time was associated with an increase in the incidence rate of unipolar depressive episodes. Distress associated with the sudden advancement of sunset, marking the coming of a long period of short days, may explain this finding. See video abstract at, http://links.lww.com/EDE/B179.

  10. Commuting to work: RN travel time to employment in rural and urban areas.

    Science.gov (United States)

    Rosenberg, Marie-Claire; Corcoran, Sean P; Kovner, Christine; Brewer, Carol

    2011-02-01

    To investigate the variation in average daily travel time to work among registered nurses (RNs) living in urban, suburban, and rural areas. We examine how travel time varies across RN characteristics, job setting, and availability of local employment opportunities. Descriptive statistics and linear regression using a 5% sample from the 2000 Census and a longitudinal survey of newly licensed RNs (NLRN). Travel time for NLRN respondents was estimated using geographic information systems (GIS) software. In the NLRN, rural nurses and those living in small towns had significantly longer average commute times. Young married RNs and RNs with children also tended to have longer commute times, as did RNs employed by hospitals. The findings indicate that travel time to work varies significantly across locale types. Further research is needed to understand whether and to what extent lengthy commute times impact RN workforce needs in rural and urban areas.

  11. Seismic model of Mars. 2. Free oscillations and travel times

    Science.gov (United States)

    Gudkova, Tamara; Lognonne, Philippe; Raevskiy, Sergey; Zharkov, Vladimir

    When constructing an interior structure model of a planet, it is common used method to describe the model by a restricted set of parameters: the thickness of the crust, the location of phase transitions, the core radius. The variation of these parameters originates from the uncertainties in temperature profile, composition, elastic and anelastic properties of relevant minerals. Water content should also be considered as a compositional variable in the mantle. Olivine and its high pressure phases, wadsleyite and ringwoodite are particularly important as they constitute about 60 wt% of the Martian mantle and have probably large capacity for water in the Martian mantle (Zharkov and Gudkova, 2014). At present Mars’ internal density distribution is constrained by the recent estimates of the moment of inertia and the Love number k _{2} (Konoplive et al., 2011). Below we use the data from Earth studies and laboratory data (Mao et al., 2010, 2011, 2012,extrapolated for P-T conditions in Mars, and show how the admixture of water in the main Martian minerals influences velocity drops at phase transition boundaries in Martian interiors and study the effects of hydration on the periods of free oscillations and travel times for P, PcP, S, ScS waves , which could serve as additional constraints, if upcoming seismic experiments are successful, as they can potentially constrain mantle composition and make more precise the location of transition zones. It is of importance to determine the depth of the phase transitions in the mantle, as it will fix the temperature profile in Mars. Our analysis is based on a trial seismic model M14_3 from (Zharkov et al., 2009). The crust is 50 km thick (with density of 2.9 g/cm (3) ), the molar ratio Fe/(Fe+Mg) in the mantle is 0.20, the Fe-Ni core contains 70 mol % H in addition to 14 wt % S with radius of 1800 km. The bulk Fe/Si ratio is close to chondritic 1.7. The upper mantle extends down to 1590 km depth. Olivine-wadsleite transition zone

  12. The influence of travel time on breast cancer characteristics, receipt of primary therapy, and surveillance mammography.

    Science.gov (United States)

    Onega, Tracy; Cook, Andrea; Kirlin, Beth; Shi, Xun; Alford-Teaster, Jennifer; Tuzzio, Leah; Buist, Diana S M

    2011-08-01

    Travel time has been shown to influence some aspects of cancer characteristics at diagnosis and care for women with breast cancer, but important gaps remain in our understanding of its impact. We examined the influence of travel time to the nearest radiology facility on breast cancer characteristics, treatment, and surveillance for women with early-stage invasive breast cancer. We included 1,012 women with invasive breast cancer (stages I and II) who had access to care within an integrated health care delivery system in western Washington State. The travel times to the nearest radiology facility were calculated for all the U.S. Census blocks within the study area and assigned to women based on residence at diagnosis. We collected cancer characteristics, primary and adjuvant therapies, and surveillance mammography for at least 2.5 years post diagnosis and used multivariable analyses to test the associations of travel time. The majority of women (68.6%) lived within 20 min of the nearest radiology facility, had stage I disease (72.7%), received breast conserving therapy (68.7%), and had annual surveillance mammography the first 2 years after treatment (73.7%). The travel time was not significantly associated with the stage or surveillance mammography after adjusting for covariates. Primary therapy was significantly related to travel time, with greater travel time (>30 min vs. ≤ 10 min) associated with a higher likelihood of mastectomy compared to breast conserving surgery (RR = 1.53; 95% CI, 1.16-2.01). The travel time was not associated with the stage at diagnosis or surveillance mammography receipt. The travel time does seem to influence the type of primary therapy among women with breast cancer, suggesting that women may prefer low frequency services, such as mastectomy, if geographic access to a radiology facility is limited.

  13. Screen time and passive school travel as independent predictors of cardiorespiratory fitness in youth.

    Science.gov (United States)

    Sandercock, Gavin R H; Ogunleye, Ayodele A

    2012-05-01

    The most prevalent sedentary behaviours in children and adolescents are engagement with small screen media (screen-time) and passive travel (by motorised vehicle). The objective of this research was to assess the independence of these behaviours from one another and from physical activity as predictors of cardiorespiratory fitness in youth. We measured cardiorespiratory fitness in n=6819 10-16 year olds (53% male) who self-reported their physical activity (7-day recall) school travel and screen time habits. Travel was classified as active (walking, cycling) or passive; screen time as 4 h. The multivariate odds of being fit were higher in active travel (Boys: OR 1.32, 95% CI: 1.09-1.59; Girls: OR 1.46, 1.15-1.84) than in passive travel groups. Boys reporting low screen time were more likely to be fit than those reporting >4 h (OR 2.11, 95% CI: 1.68-2.63) as were girls (OR 1.66, 95% CI: 1.24-2.20). These odds remained significant after additionally controlling for physical activity. Passive travel and high screen time are independently associated with poor cardiorespiratory fitness in youth, and this relationship is independent of physical activity levels. A lifestyle involving high screen time and habitual passive school travel appears incompatible with healthful levels of cardiorespiratory fitness in youth. Copyright © 2012 Elsevier Inc. All rights reserved.

  14. Potential time savings to radiology department personnel in a PACS-based environment

    Science.gov (United States)

    Saarinen, Allan O.; Wilson, M. C.; Iverson, Scott C.; Loop, John W.

    1990-08-01

    A purported benefit of digital imaging and archiving of radiographic procedures is the presumption of time savings to radiologists, radiology technologists, and radiology departmentpersonnel involved with processingfilms and managing theflimfile room. As part of the University of Washington's evaluation of Picture Archiving and Communication Systems (PACS)for the U.S. Army Medical Research and Development Command, a study was performed which evaluated the current operationalpractices of the film-based radiology department at the University of Washington Medical Center (UWMC). Industrial engineering time and motion studies were conducted to document the length of time requiredforfilm processing in various modalities, the proportion of the total exam time usedforfilm processing, the amount of time radiologists spent searchingfor and looking at images, and the amount of time file room personnel spent collating reports, making loans, updatingfilm jacket information, and purging files. This evaluation showed that better than one-half of the tasks in the file room may be eliminated with PACS and radiologists may save easily 10 percent of the time they spend reading films by no longer having to searchforfilms. Radiology technologists may also save as much as 10 percent of their time with PACS, although this estimate is subject to significant patient mix aberrations and measurement error. Given that the UWMC radiology department operates efficiently, similar improvements are forecast for other radiology departments and larger improvements areforecastfor less efficient departments.

  15. Time travels in archaeology. Between Hollywood films and historical re-enactment?

    Directory of Open Access Journals (Sweden)

    Dawid Kobialka

    2017-01-01

    Full Text Available One of the recently most popular ways of experiencing the past is time travelling. It is ‘an experience and social practice in the present that evokes a past (or future reality’ (Holtorf 2009: 33. In this article, I mainly discuss the political aspect of time travelling. I focus on cinema as a medium which closely links archaeology with the time travel phenomenon. Two Oscars galas, of 2010 and 2012, are scrutinised as case studies. The text is a political intervention to start dreaming dangerously, to contribute as an archaeologist to the critique of the utopia of capitalism (see also Hernando 2005: 75.

  16. Tile Drainage Density Reduces Groundwater Travel Times and Compromises Riparian Buffer Effectiveness.

    Science.gov (United States)

    Schilling, Keith E; Wolter, Calvin F; Isenhart, Thomas M; Schultz, Richard C

    2015-11-01

    Strategies to reduce nitrate-nitrogen (nitrate) pollution delivered to streams often seek to increase groundwater residence time to achieve measureable results, yet the effects of tile drainage on residence time have not been well documented. In this study, we used a geographic information system groundwater travel time model to quantify the effects of artificial subsurface drainage on groundwater travel times in the 7443-ha Bear Creek watershed in north-central Iowa. Our objectives were to evaluate how mean groundwater travel times changed with increasing drainage intensity and to assess how tile drainage density reduces groundwater contributions to riparian buffers. Results indicate that mean groundwater travel times are reduced with increasing degrees of tile drainage. Mean groundwater travel times decreased from 5.6 to 1.1 yr, with drainage densities ranging from 0.005 m (7.6 mi) to 0.04 m (62 mi), respectively. Model simulations indicate that mean travel times with tile drainage are more than 150 times faster than those that existed before settlement. With intensive drainage, less than 2% of the groundwater in the basin appears to flow through a perennial stream buffer, thereby reducing the effectiveness of this practice to reduce stream nitrate loads. Hence, strategies, such as reconnecting tile drainage to buffers, are promising because they increase groundwater residence times in tile-drained watersheds. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  17. Travel Cost Inference from Sparse, Spatio-Temporally Correlated Time Series Using Markov Models

    DEFF Research Database (Denmark)

    Yang, Bin; Guo, Chenjuan; Jensen, Christian S.

    2013-01-01

    of such time series offers insight into the underlying system and enables prediction of system behavior. While the techniques presented in the paper apply more generally, we consider the case of transportation systems and aim to predict travel cost from GPS tracking data from probe vehicles. Specifically, each...... road segment has an associated travel-cost time series, which is derived from GPS data. We use spatio-temporal hidden Markov models (STHMM) to model correlations among different traffic time series. We provide algorithms that are able to learn the parameters of an STHMM while contending...... with the sparsity, spatio-temporal correlation, and heterogeneity of the time series. Using the resulting STHMM, near future travel costs in the transportation network, e.g., travel time or greenhouse gas emissions, can be inferred, enabling a variety of routing services, e.g., eco-routing. Empirical studies...

  18. Travel cost inference from sparse, spatio-temporally correlated time series using markov models

    DEFF Research Database (Denmark)

    Yang, B.; Guo, C.; Jensen, C.S.

    2013-01-01

    of such time series offers insight into the underlying system and enables prediction of system behavior. While the techniques presented in the paper apply more generally, we consider the case of transportation systems and aim to predict travel cost from GPS tracking data from probe vehicles. Specifically, each...... road segment has an associated travel-cost time series, which is derived from GPS data. We use spatio-temporal hidden Markov models (STHMM) to model correlations among different traffic time series. We provide algorithms that are able to learn the parameters of an STHMM while contending...... with the sparsity, spatio-temporal correlation, and heterogeneity of the time series. Using the resulting STHMM, near future travel costs in the transportation network, e.g., travel time or greenhouse gas emissions, can be inferred, enabling a variety of routing services, e.g., eco-routing. Empirical studies...

  19. Effect of Automobile Travel Time Between Patients' Homes and Ophthalmologists' Offices on Screening for Diabetic Retinopathy.

    Science.gov (United States)

    Macon, Céline; Carrier, Hélène; Janczewski, Aurélie; Verger, Pierre; Casanova, Ludovic

    2018-01-01

    The accessibility of ophthalmologists appears to influence the quality of screening for diabetic retinopathy (DR). The principal objective of this study was to analyze the effect of automobile travel time to the closest ophthalmologist on the time to DR screening. This historical cohort study used reimbursement databases from the principal national health insurance fund. Patients were included if they had been reimbursed at least thrice for oral antidiabetic medications in the 12 months before the study start date. Patients were followed up from January 1, 2008, for 4 years. The expected event was a DR screening by an ocular fundus examination. The automobile travel time to the nearest ophthalmologist was calculated by the distance between communes, estimated by appropriate software. A Kaplan-Meier curve and a multivariate Cox model were used to model the effect of travel time on the time until DR screening. A sensitivity analysis of travel time described the results of the Cox model. At the start of 2008, 6,573 patients living in 328 different municipalities were included. The multivariate model found that patients living 60 min or more away from an ophthalmologist had a lower instantaneous probability of DR screening than those living travel time. Increased automobile travel time for patients with diabetes to the nearest ophthalmologist was associated with a longer time to DR screening.

  20. New time-saving predictor algorithm for multiple breath washout in adolescents

    DEFF Research Database (Denmark)

    Grønbæk, Jonathan; Hallas, Henrik Wegener; Arianto, Lambang

    2016-01-01

    BACKGROUND: Multiple breath washout (MBW) is an informative but time-consuming test. This study evaluates the uncertainty of a time-saving predictor algorithm in adolescents. METHODS: Adolescents were recruited from the Copenhagen Prospective Study on Asthma in Childhood (COPSAC2000) birth cohort...... algorithm holds promise in shortening the MBW test in children but should be used with caution in subjects with normal LCI values....

  1. Developing corridor-level truck travel time estimates and other freight performance measures from archived ITS data.

    Science.gov (United States)

    2009-08-01

    The objectives of this research were to retrospectively study the feasibility for using truck transponder data to produce freight corridor performance measures (travel times) and real-time traveler information. To support this analysis, weigh-in-moti...

  2. Evaluation of Effective Factors on Travel Time in Optimization of Bus Stops Placement Using Genetic Algorithm

    Science.gov (United States)

    Bargegol, Iraj; Ghorbanzadeh, Mahyar; Ghasedi, Meisam; Rastbod, Mohammad

    2017-10-01

    In congested cities, locating and proper designing of bus stops according to the unequal distribution of passengers is crucial issue economically and functionally, since this subject plays an important role in the use of bus system by passengers. Location of bus stops is a complicated subject; by reducing distances between stops, walking time decreases, but the total travel time may increase. In this paper, a specified corridor in the city of Rasht in north of Iran is studied. Firstly, a new formula is presented to calculate the travel time, by which the number of stops and consequently, the travel time can be optimized. An intended corridor with specified number of stops and distances between them is addressed, the related formulas to travel time are created, and its travel time is calculated. Then the corridor is modelled using a meta-heuristic method in order that the placement and the optimal distances of bus stops for that are determined. It was found that alighting and boarding time along with bus capacity are the most effective factors affecting travel time. Consequently, it is better to have more concentration on indicated factors for improving the efficiency of bus system.

  3. Dynamic Bus Travel Time Prediction Models on Road with Multiple Bus Routes.

    Science.gov (United States)

    Bai, Cong; Peng, Zhong-Ren; Lu, Qing-Chang; Sun, Jian

    2015-01-01

    Accurate and real-time travel time information for buses can help passengers better plan their trips and minimize waiting times. A dynamic travel time prediction model for buses addressing the cases on road with multiple bus routes is proposed in this paper, based on support vector machines (SVMs) and Kalman filtering-based algorithm. In the proposed model, the well-trained SVM model predicts the baseline bus travel times from the historical bus trip data; the Kalman filtering-based dynamic algorithm can adjust bus travel times with the latest bus operation information and the estimated baseline travel times. The performance of the proposed dynamic model is validated with the real-world data on road with multiple bus routes in Shenzhen, China. The results show that the proposed dynamic model is feasible and applicable for bus travel time prediction and has the best prediction performance among all the five models proposed in the study in terms of prediction accuracy on road with multiple bus routes.

  4. Dynamic Bus Travel Time Prediction Models on Road with Multiple Bus Routes

    Science.gov (United States)

    Bai, Cong; Peng, Zhong-Ren; Lu, Qing-Chang; Sun, Jian

    2015-01-01

    Accurate and real-time travel time information for buses can help passengers better plan their trips and minimize waiting times. A dynamic travel time prediction model for buses addressing the cases on road with multiple bus routes is proposed in this paper, based on support vector machines (SVMs) and Kalman filtering-based algorithm. In the proposed model, the well-trained SVM model predicts the baseline bus travel times from the historical bus trip data; the Kalman filtering-based dynamic algorithm can adjust bus travel times with the latest bus operation information and the estimated baseline travel times. The performance of the proposed dynamic model is validated with the real-world data on road with multiple bus routes in Shenzhen, China. The results show that the proposed dynamic model is feasible and applicable for bus travel time prediction and has the best prediction performance among all the five models proposed in the study in terms of prediction accuracy on road with multiple bus routes. PMID:26294903

  5. IYL Blog: Astronomers travel in time and space with light

    Science.gov (United States)

    Mather, John C.

    2015-01-01

    As an astronomer, I use light to travel through the universe, and to look back in time to when the universe was young. So do you! All of us see things as they were when the light was emitted, not as they are now. The farthest thing you can easily see without a telescope is the Andromeda Nebula, which is a galaxy like the Milky Way, about 2.5 million light years away. You see it as it was 2.5 million years ago, and we really don't know what it looks like today; the disk will have rotated a bit, new stars will have been born, there could have been all kinds of exploding stars, and the black hole in the middle could be lighting up. People may be skeptical of the Big Bang theory, even though we have a TV show named for it, but we (I should say Penzias and Wilson) measured its heat radiation 51 years ago at Bell Telephone Labs in New Jersey. Their discovery marks the beginning of the era of cosmology as a measurement science rather than speculation. Penzias and Wilson received the Nobel Prize in 1978 for their finding, which had been predicted in 1948 by Alpher and Herman. By the way, heat radiation is just another form of light - we call it radiation because we can't see it, but it's exactly the same phenomenon of electromagnetic waves, and the only difference is the wavelength. In the old days of analog television, if you tuned your TV in between channels, about 1% of the snow that you could see came from the Big Bang. So when we look at the heat radiation of the early universe, we really are gazing right at what seems to us a cosmic fireball, which surrounds us completely. It's a bit of an illusion; if you can imagine what astronomers in other galaxies would see, they would also feel surrounded by the fireball, and they would also think they were in the middle. So from a mathematical version of imagination, we conclude that there is no observable center and no edge of our universe, and that the heat of the fireball fills the entire universe uniformly. Astronomers are

  6. State Estimates of the Northern Philippine Sea Circulation Including Ocean Acoustic Travel Times

    Science.gov (United States)

    Cornuelle, B. D.; Gopalakrishnan, G.; Mazloff, M. R.; Worcester, P. F.; Dzieciuch, M. A.

    2016-02-01

    The North Pacific Acoustic Laboratory (NPAL) Philippine Sea experiment deployed a variety of instruments in the northern Philippine Sea during April 2010 through April 2011, including 6 acoustic transceivers for reciprocal measurements of travel times between instruments. Five of the transceivers were moored in a pentagon approximately 660 km in diameter with the sixth transceiver mooring in the center. A seventh mooring approximately 130 km northwest of the center supported a Distributed Vertical Line Array (DVLA) which carried 149 acoustic receivers with thermistors covering the depths between 200 m and 5500 m. The goals of the experiment included studying the energetic westward-propagating eddies which travel through the region, their effect on underwater sound propagation, and the impact of acoustic measurements on estimates of the time-evolving ocean state. Observed travel-time time series were compared with travel times computed from ocean state estimates made using an eddy-active regional implementation of the MITgcm that were constrained by satellite sea surface height and sea surface temperature observations and by temperature and salinity profiles from Argo, CTDs, and XBTs but not by the acoustic data. The similarities cross-validate the state estimates, while the differences provide a simple estimate of the novel information present in the travel times. The ocean state estimates were then re-computed to fit the acoustic travel times as integrals of the sound speed, and therefore temperature and salinity, along the ray paths. Over the approximately 1 year experiment, the state estimate was able to match the travel times within their error bars and did not significantly increase the misfits with the other observations. Comparisons of the state estimates with and without the travel-time data showed significant changes to the temperature and salinity were made to fit the acoustic observations. The state estimates using the acoustic data compare favorably

  7. Comparison of methods for measuring travel time at Florida freeways and arterials : [summary].

    Science.gov (United States)

    2014-07-01

    In this project, University of Florida researchers : collected field data along several highways to : evaluate travel time measurements from several : sources: STEWARD, BlueTOAD, INRIX, and HERE. : STEWARD (Statewide Transportation Engineering : Ware...

  8. Wireless data collection system for travel time estimation and traffic performance evaluation.

    Science.gov (United States)

    2012-05-01

    This report presents the results of the third and final research and development project of an implementable wireless : travel time data collection system. Utilizing Bluetooth wireless technology as a platform, the prior projects focused on : data co...

  9. Freeway travel time estimation using existing fixed traffic sensors : phase 1.

    Science.gov (United States)

    2013-08-01

    Freeway travel time is one of the most useful pieces of information for road users and an : important measure of effectiveness (MOE) for traffic engineers and policy makers. In the Greater : St. Louis area, Gateway Guide, the St. Louis Transportation...

  10. Analysis of Modal Travel Time Variability Due to Mesoscale Ocean Structure

    National Research Council Canada - National Science Library

    Smith, Amy

    1997-01-01

    .... First, for an open ocean environment away from strong boundary currents, the effects of randomly phased linear baroclinic Rossby waves on acoustic travel time are shown to produce a variable overall...

  11. Incorporating travel-time reliability into the congestion management process : a primer.

    Science.gov (United States)

    2015-02-01

    This primer explains the value of incorporating travel-time reliability into the Congestion Management Process (CMP) : and identifies the most current tools available to assist with this effort. It draws from applied research and best practices : fro...

  12. Space-Time Hybrid Model for Short-Time Travel Speed Prediction

    Directory of Open Access Journals (Sweden)

    Qi Fan

    2018-01-01

    Full Text Available Short-time traffic speed forecasting is a significant issue for developing Intelligent Transportation Systems applications, and accurate speed forecasting results are necessary inputs for Intelligent Traffic Security Information System (ITSIS and advanced traffic management systems (ATMS. This paper presents a hybrid model for travel speed based on temporal and spatial characteristics analysis and data fusion. This proposed methodology predicts speed by dividing the data into three parts: a periodic trend estimated by Fourier series, a residual part modeled by the ARIMA model, and the possible events affected by upstream or downstream traffic conditions. The aim of this study is to improve the accuracy of the prediction by modeling time and space variation of speed, and the forecast results could simultaneously reflect the periodic variation of traffic speed and emergencies. This information could provide decision-makers with a basis for developing traffic management measures. To achieve the research objective, one year of speed data was collected in Twin Cities Metro, Minnesota. The experimental results demonstrate that the proposed method can be used to explore the periodic characteristics of speed data and show abilities in increasing the accuracy of travel speed prediction.

  13. Variation in Patients' Travel Times among Imaging Examination Types at a Large Academic Health System.

    Science.gov (United States)

    Rosenkrantz, Andrew B; Liang, Yu; Duszak, Richard; Recht, Michael P

    2017-08-01

    Patients' willingness to travel farther distances for certain imaging services may reflect their perceptions of the degree of differentiation of such services. We compare patients' travel times for a range of imaging examinations performed across a large academic health system. We searched the NYU Langone Medical Center Enterprise Data Warehouse to identify 442,990 adult outpatient imaging examinations performed over a recent 3.5-year period. Geocoding software was used to estimate typical driving times from patients' residences to imaging facilities. Variation in travel times was assessed among examination types. The mean expected travel time was 29.2 ± 20.6 minutes, but this varied significantly (p travel times were shortest for ultrasound (26.8 ± 18.9) and longest for positron emission tomography-computed tomography (31.9 ± 21.5). For magnetic resonance imaging, travel times were shortest for musculoskeletal extremity (26.4 ± 19.2) and spine (28.6 ± 21.0) examinations and longest for prostate (35.9 ± 25.6) and breast (32.4 ± 22.3) examinations. For computed tomography, travel times were shortest for a range of screening examinations [colonography (25.5 ± 20.8), coronary artery calcium scoring (26.1 ± 19.2), and lung cancer screening (26.4 ± 14.9)] and longest for angiography (32.0 ± 22.6). For ultrasound, travel times were shortest for aortic aneurysm screening (22.3 ± 18.4) and longest for breast (30.1 ± 19.2) examinations. Overall, men (29.9 ± 21.6) had longer (p travel times than women (27.8 ± 20.3); this difference persisted for each modality individually (p ≤ 0.006). Patients' willingness to travel longer times for certain imaging examination types (particularly breast and prostate imaging) supports the role of specialized services in combating potential commoditization of imaging services. Disparities in travel times by gender warrant further investigation. Copyright

  14. Leisure and the Opportunity Cost of Travel Time in Recreation Demand Analysis: A Re-Examination

    OpenAIRE

    Amoako-Tuffour, Joe; Martınez-Espineira, Roberto

    2008-01-01

    Using count data models that account for zero-truncation, overdispersion, and endogenous stratification, this paper estimates the value of access to recreational parks. The focus is on the valuation of the opportunity cost of travel time within the cost of the trip and its effects on estimated consumer surplus. The fraction of hourly earnings that corresponds to the opportunity cost of travel time is endogenously estimated as a function of visitor characteristics, rather than fixed exogenousl...

  15. Racial disparities in travel time to radiotherapy facilities in the Atlanta metropolitan area.

    Science.gov (United States)

    Peipins, Lucy A; Graham, Shannon; Young, Randall; Lewis, Brian; Flanagan, Barry

    2013-07-01

    Low-income women with breast cancer who rely on public transportation may have difficulty in completing recommended radiation therapy due to inadequate access to radiation facilities. Using a geographic information system (GIS) and network analysis we quantified spatial accessibility to radiation treatment facilities in the Atlanta, Georgia metropolitan area. We built a transportation network model that included all bus and rail routes and stops, system transfers and walk and wait times experienced by public transportation system travelers. We also built a private transportation network to model travel times by automobile. We calculated travel times to radiation therapy facilities via public and private transportation from a population-weighted center of each census tract located within the study area. We broadly grouped the tracts by low, medium and high household access to a private vehicle and by race. Facility service areas were created using the network model to map the extent of areal coverage at specified travel times (30, 45 and 60 min) for both public and private modes of transportation. The median public transportation travel time to the nearest radiotherapy facility was 56 min vs. approximately 8 min by private vehicle. We found that majority black census tracts had longer public transportation travel times than white tracts across all categories of vehicle access and that 39% of women in the study area had longer than 1 h of public transportation travel time to the nearest facility. In addition, service area analyses identified locations where the travel time barriers are the greatest. Spatial inaccessibility, especially for women who must use public transportation, is one of the barriers they face in receiving optimal treatment. Published by Elsevier Ltd.

  16. Transition into daylight saving time influences the fragmentation of the rest-activity cycle

    Directory of Open Access Journals (Sweden)

    Tuulio-Henriksson Annamari

    2006-01-01

    Full Text Available Abstract Background Daylight saving time is widely adopted. Little is known about its influence on the daily rest-activity cycles. We decided to explore the effects of transition into daylight saving time on the circadian rhythm of activity. Methods We monitored the rest-activity cycles with the use of wrist-worn accelerometer on a sample of ten healthy adults for ten days around the transition into summer time. Identical protocols were carried out on the same individuals in two consecutive years, yielding data on 200 person-days for analysis in this study. Results There was no significant effect on the rest-activity cycle in the sample as a whole. Fragmentation of the rest-activity cycle was enhanced in a subgroup of persons having sleep for eight hours or less (P = 0.04 but reduced in those who preferred to sleep for more than eight hours per night (P = 0.05. The average level of motor activity was increased in persons having the morning preference for daily activity patterns (P = 0.01. Conclusion Transition into daylight saving time may have a disruptive effect on the rest-activity cycle in those healthy adults who are short-sleepers or more of the evening type.

  17. Saving billions of dollars--and physicians' time--by streamlining billing practices.

    Science.gov (United States)

    Blanchfield, Bonnie B; Heffernan, James L; Osgood, Bradford; Sheehan, Rosemary R; Meyer, Gregg S

    2010-06-01

    The U.S. system of billing third parties for health care services is complex, expensive, and inefficient. Physicians end up using nearly 12 percent of their net patient service revenue to cover the costs of excessive administrative complexity. A single transparent set of payment rules for multiple payers, a single claim form, and standard rules of submission, among other innovations, would reduce the burden on the billing offices of physician organizations. On a national scale, our hypothetical modeling of these changes would translate into $7 billion of savings annually for physician and clinical services. Four hours of professional time per physician and five hours of practice support staff time could be saved each week.

  18. Effects of a workplace travel plan intervention encouraging active travel to work: outcomes from a three-year time-series study.

    Science.gov (United States)

    Petrunoff, N; Wen, L M; Rissel, C

    2016-06-01

    To evaluate the effects of a three-year workplace travel plan intervention on increasing active travel to work. A time-series study with staff was conducted in 2011 (n = 804), 2012 (n = 904), 2013 (n = 872) and 2014 (n = 687). A travel plan was implemented at a large, outer-suburban worksite in Sydney, Australia. Implementation was assessed by reviewing annual reports including travel plan actions and their status. Annual cross-sectional on-line surveys assessed primary outcomes which included change in the proportion of staff travelling to work via active modes. Multivariate logistic regression was used to adjust for confounders. Strategies to encourage active travel were partially implemented. An average survey response rate was 23% (n = 817). The proportion of staff travelling actively to work increased by 4%-6% across intervention years compared to the baseline, and this increase was significant in 2012 (P = 0.04) and 2013 (P = 0.003). Compared to baseline, after adjusting for distances staff lived from work staff had 33% (95% CI 1%-74%) greater odds of travelling to work via active modes in 2012, and 50% (95% CI 15%-96%) greater odds in 2013. There was no evidence of change in physical activity levels. A workplace travel plan which only included strategies to encourage active travel to work achieved small but significant increases in active travel. Workplace travel plans appear to be a promising way to increase active travel to work. Copyright © 2016 The Royal Society for Public Health. All rights reserved.

  19. Estimating Travel Time in Bank Filtration Systems from a Numerical Model Based on DTS Measurements.

    Science.gov (United States)

    des Tombe, Bas F; Bakker, Mark; Schaars, Frans; van der Made, Kees-Jan

    2018-03-01

    An approach is presented to determine the seasonal variations in travel time in a bank filtration system using a passive heat tracer test. The temperature in the aquifer varies seasonally because of temperature variations of the infiltrating surface water and at the soil surface. Temperature was measured with distributed temperature sensing along fiber optic cables that were inserted vertically into the aquifer with direct push equipment. The approach was applied to a bank filtration system consisting of a sequence of alternating, elongated recharge basins and rows of recovery wells. A SEAWAT model was developed to simulate coupled flow and heat transport. The model of a two-dimensional vertical cross section is able to simulate the temperature of the water at the well and the measured vertical temperature profiles reasonably well. MODPATH was used to compute flowpaths and the travel time distribution. At the study site, temporal variation of the pumping discharge was the dominant factor influencing the travel time distribution. For an equivalent system with a constant pumping rate, variations in the travel time distribution are caused by variations in the temperature-dependent viscosity. As a result, travel times increase in the winter, when a larger fraction of the water travels through the warmer, lower part of the aquifer, and decrease in the summer, when the upper part of the aquifer is warmer. © 2017 The Authors. Groundwater published by Wiley Periodicals, Inc. on behalf of National Ground Water Association.

  20. Extended operating times are more efficient, save money and maintain a high staff and patient satisfaction.

    Science.gov (United States)

    Herron, Jonathan Blair Thomas; French, Rachel; Gilliam, Andrew Douglas

    2018-01-01

    Current public sector austerity measures necessitate efficiency savings throughout the NHS. Performance targets have resulted in activity being performed in the private sector, waiting list initiative lists and requests for staff to work overtime. This has resulted in staff fatigue and additional agency costs. Adoption of extended operating theatre times (0800-1800 hours) may improve productivity and efficiency, with potentially significant financial savings; however, implementation may adversely affect staff morale and patient compliance. A pilot period of four months of extended operating times (4.5 hour sessions) was completed and included all theatre surgical specialties. Outcome measures included: the number of cases completed, late starts, early finishes, cancelled operations, theatre overruns, preoperative assessment and 18-week targets. The outcomes were then compared to pre-existing normal working day operating lists (0900-1700). Theatre staff, patient and surgical trainee satisfaction with the system were also considered by use of an anonymous questionnaire. The study showed that in-session utilisation time was unchanged by extended operating hours 88.7% (vs 89.2%). The service was rated as 'good' or 'excellent' by 87.5% of patients. Over £345,000 was saved by reducing premium payments. Savings of £225,000 were made by reducing privately outsourced operation and a further £63,000 by reviewing staff hours. Day case procedures increased from 2.8 to 3.2 cases/day with extended operating. There was no significant increase in late starts (5.1% vs 6.8%) or cancellation rates (0.75% vs 1.02%). Theatre over-runs reduced from 5% to 3.4%. The 18 weeks target for surgery was achieved in 93.7% of cases (vs 88.3%). The number of elective procedures increased from 4.1 to 4.89 cases/day. Only 13.33% of trainees (n = 33) surveyed felt that extended operating had a negative impact on training. The study concludes that extended operating increased productivity from

  1. Quantifying Adoption Rates and Energy Savings Over Time for Advanced Manufacturing Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Hanes, Rebecca [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Carpenter Petri, Alberta C [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Riddle, Matt [Argonne National Laboratory; Graziano, Diane [Argonne National Laboratory

    2017-10-09

    Energy-efficient manufacturing technologies can reduce energy consumption and lower operating costs for an individual manufacturing facility, but increased process complexity and the resulting risk of disruption means that manufacturers may be reluctant to adopt such technologies. In order to quantify potential energy savings at scales larger than a single facility, it is necessary to account for how quickly and how widely the technology will be adopted by manufacturers. This work develops a methodology for estimating energy-efficient manufacturing technology adoption rates using quantitative, objectively measurable technology characteristics, including energetic, economic and technical criteria. Twelve technology characteristics are considered, and each characteristic is assigned an importance weight that reflects its impact on the overall technology adoption rate. Technology characteristic data and importance weights are used to calculate the adoption score, a number between 0 and 1 that represents how quickly the technology is likely to be adopted. The adoption score is then used to estimate parameters for the Bass diffusion curve, which quantifies the change in the number of new technology adopters in a population over time. Finally, energy savings at the sector level are calculated over time by multiplying the number of new technology adopters at each time step with the technology's facility-level energy savings. The proposed methodology will be applied to five state-of-the-art energy-efficient technologies in the carbon fiber composites sector, with technology data obtained from the Department of Energy's 2016 bandwidth study. Because the importance weights used in estimating the Bass curve parameters are subjective, a sensitivity analysis will be performed on the weights to obtain a range of parameters for each technology. The potential energy savings for each technology and the rate at which each technology is adopted in the sector are quantified

  2. Valuation of travel time for international long-distance travel - results from the Fehmarn Belt stated choice experiment

    DEFF Research Database (Denmark)

    Mabit, Stefan Lindhard; Rich, Jeppe; Burge, Peter

    2013-01-01

    The geographical scope of travel varies from short distances in urban areas to long distances across cities and countries. While urban travel has been widely analysed in the literature, travel over longer distances and particularly across countries, has received much less attention. While this ma...

  3. Existence and Stability of Traveling Waves for Degenerate Reaction-Diffusion Equation with Time Delay

    Science.gov (United States)

    Huang, Rui; Jin, Chunhua; Mei, Ming; Yin, Jingxue

    2018-01-01

    This paper deals with the existence and stability of traveling wave solutions for a degenerate reaction-diffusion equation with time delay. The degeneracy of spatial diffusion together with the effect of time delay causes us the essential difficulty for the existence of the traveling waves and their stabilities. In order to treat this case, we first show the existence of smooth- and sharp-type traveling wave solutions in the case of c≥c^* for the degenerate reaction-diffusion equation without delay, where c^*>0 is the critical wave speed of smooth traveling waves. Then, as a small perturbation, we obtain the existence of the smooth non-critical traveling waves for the degenerate diffusion equation with small time delay τ >0 . Furthermore, we prove the global existence and uniqueness of C^{α ,β } -solution to the time-delayed degenerate reaction-diffusion equation via compactness analysis. Finally, by the weighted energy method, we prove that the smooth non-critical traveling wave is globally stable in the weighted L^1 -space. The exponential convergence rate is also derived.

  4. Penanganan Fuzzy Time Window pada Travelling Salesman Problem (TSP dengan Penerapan Algoritma Genetika

    Directory of Open Access Journals (Sweden)

    Gusti Eka Yuliastuti

    2017-03-01

    Full Text Available The route of the travel tour packages offered by travel agents is not considered optimum, so the level of satisfaction the tourist is not maximal. Selection of the route of the travel packages included in the traveling salesman problem (TSP. The problem that occurs is uncertain tourists visiting destinations at the best destinations timing hereinafter be referred to as the fuzzy time window problem. Therefore, the authors apply the genetic algorithm to solve the problem. Based on test results obtained optimum solution with the fitness value of 1.3291, a population size of 100, the number of generations of 1000, a combination of CR=0,4 and MR=0.6.

  5. Exploring the acceptable travel time concept in the US and European contexts. Results from Berkeley, CA and Delft, The Netherlands

    NARCIS (Netherlands)

    Milakis, D.; van Wee, G.P.

    2016-01-01

    “Do people consider an acceptable travel time?” We raised this question in Milakis, Cervero, and van Wee (2015) to explore the validity of the acceptable travel time concept as a possible factor in the travel and destination decision-making process. Results from interviews with 20 subjects in

  6. Dynamic Travel Time Prediction Models for Buses Using Only GPS Data

    Directory of Open Access Journals (Sweden)

    Wei Fan

    2015-01-01

    Full Text Available Providing real-time and accurate travel time information of transit vehicles can be very helpful as it assists passengers in planning their trips to minimize waiting times. The purpose of this research is to develop and compare dynamic travel time prediction models which can provide accurate prediction of bus travel time in order to give real-time information at a given downstream bus stop using only global positioning system (GPS data. Historical Average (HA, Kalman Filtering (KF and Artificial Neural Network (ANN models are considered and developed in this paper. A case has been studied by making use of the three models. Promising results are obtained from the case study, indicating that the models can be used to implement an Advanced Public Transport System. The implementation of this system could assist transit operators in improving the reliability of bus services, thus attracting more travelers to transit vehicles and helping relieve congestion. The performances of the three models were assessed and compared with each other under two criteria: overall prediction accuracy and robustness. It was shown that the ANN outperformed the other two models in both aspects. In conclusion, it is shown that bus travel time information can be reasonably provided using only arrival and departure time information at stops even in the absence of traffic-stream data.

  7. A Quantitative Analysis of the Relationship Between Radiation Therapy Use and Travel Time.

    Science.gov (United States)

    Liu, Emma; Santibáñez, Pablo; Puterman, Martin L; Weber, Leah; Ma, Xiang; Sauré, Antoine; Olivotto, Ivo A; Halperin, Ross; French, John; Tyldesley, Scott

    2015-11-01

    To model and quantify the relationship between radiation therapy (RT) use and travel time to RT services. Population-based registries and databases were used to identify both incident cancer patient and patients receiving RT within 1 year of diagnosis (RT1y) in British Columbia, Canada, between 1992 and 2011. The effects of age, gender, diagnosis year, income, prevailing wait time, and travel duration for RT on RT1y were assessed. Significant factors from univariate analyses were included in a multivariable logistic regression model. The shape of the travel time-RT1y curve was represented by generalized additive and segmented regression models. Analyses were conducted for breast, lung, and genitourinary cancer separately and for all cancer sites combined. After adjustment for age, gender, diagnosis year, income, and prevailing wait times, increasing travel time to the closest RT facility had a negative impact RT1y. The shape of the travel time-RT1y curve varied with cancer type. For breast cancer, the odds of RT1y were constant for the first 2 driving hours and decreased at 17% per hour thereafter. For lung cancer, the odds of RT1y decreased by 16% after 20 minutes and then decreased at 6% per hour. Genitourinary cancer RT1y was relatively independent of travel time. For all cancer sites combined, the odds of RT1y were constant within the first 2 driving hours and decreased at 7% per hour thereafter. Travel time to receive RT has a different impact on RT1y for different tumor sites. The results provide evidence-based insights for the configuration of catchment areas for new and existing cancer centers providing RT. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  8. Effects of daylight-saving time changes on stock market volatility: a comment.

    Science.gov (United States)

    Kamstra, Mark J; Kramer, Lisa A; Levi, Maurice D

    2010-12-01

    In a recent article in this journal, Berument, Dogan, and Onar (2010) challenged the existence of the previously documented daylight-saving effect. Kamstra, Kramer, and Levi's original finding (2000) was that average stock market returns on Mondays following time changes are economically and statistically significantly lower than typical Monday returns. Kamstra, et al. hypothesized that the effect may arise due to heightened anxiety or risk aversion on the part of market participants after they experience a 1-hr. disruption in their sleep habits, in accordance with prior findings in the psychology literature linking sleep desynchronosis with anxiety. Berument, et al. replicated the original findings using ordinary least squares estimation, but when they modeled the mean of returns using a method prone to producing biased estimates, they obtained puzzling results. The analysis here, based on standard, unbiased modeling techniques, shows that the daylight-saving effect remains intact in the U.S.

  9. Perinatal outcomes and travel time from home to hospital: Welsh data from 1995 to 2009.

    Science.gov (United States)

    Paranjothy, Shantini; Watkins, W John; Rolfe, Kim; Adappa, Roshan; Gong, Yi; Dunstan, Frank; Kotecha, Sailesh

    2014-12-01

    To study the association between travel time from home to hospital and birth outcomes. For all registrable births to women resident in Wales (1995-2009), we calculated the travel time between the mother's residence and the postcode-based location for both the birth hospital and all hospitals with maternity services that were open. Using logistic regression, we obtained odds ratios for the association between travel time and each birth outcome, adjusted for confounders. In our analysis of 412 827 singleton births, for every 15-min increase in travel time to the birth hospital, there was an increased risk of early (n = 609; OR: 1.13; 95%CI: 1.07, 1.20) and late neonatal death (n = 251; OR: 1.15; 95%CI: 1.05, 1.26). Results for intrapartum stillbirth were inconclusive (n = 135; OR: 1.13; 95%CI: 0.98, 1.30). For the above-combined (n = 995) results, we get OR: 1.15, 95%CI: 1.09, 1.20. No association was found with travel time to the nearest hospital (OR: 1.01; 95%CI: 0.90, 1.13 per 15-min increase in travel time) for the composite outcome of intrapartum stillbirth and neonatal deaths. Longer travel time to the birth hospital was associated with increased risk of neonatal deaths, but there was no strong evidence of association with the geographical location of maternity services. ©2014 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

  10. Road Short-Term Travel Time Prediction Method Based on Flow Spatial Distribution and the Relations

    Directory of Open Access Journals (Sweden)

    Mingjun Deng

    2016-01-01

    Full Text Available There are many short-term road travel time forecasting studies based on time series, but indeed, road travel time not only relies on the historical travel time series, but also depends on the road and its adjacent sections history flow. However, few studies have considered that. This paper is based on the correlation of flow spatial distribution and the road travel time series, applying nearest neighbor and nonparametric regression method to build a forecasting model. In aspect of spatial nearest neighbor search, three different space distances are defined. In addition, two forecasting functions are introduced: one combines the forecasting value by mean weight and the other uses the reciprocal of nearest neighbors distance as combined weight. Three different distances are applied in nearest neighbor search, which apply to the two forecasting functions. For travel time series, the nearest neighbor and nonparametric regression are applied too. Then minimizing forecast error variance is utilized as an objective to establish the combination model. The empirical results show that the combination model can improve the forecast performance obviously. Besides, the experimental results of the evaluation for the computational complexity show that the proposed method can satisfy the real-time requirement.

  11. Urban Link Travel Time Prediction Based on a Gradient Boosting Method Considering Spatiotemporal Correlations

    Directory of Open Access Journals (Sweden)

    Faming Zhang

    2016-11-01

    Full Text Available The prediction of travel times is challenging because of the sparseness of real-time traffic data and the intrinsic uncertainty of travel on congested urban road networks. We propose a new gradient–boosted regression tree method to accurately predict travel times. This model accounts for spatiotemporal correlations extracted from historical and real-time traffic data for adjacent and target links. This method can deliver high prediction accuracy by combining simple regression trees with poor performance. It corrects the error found in existing models for improved prediction accuracy. Our spatiotemporal gradient–boosted regression tree model was verified in experiments. The training data were obtained from big data reflecting historic traffic conditions collected by probe vehicles in Wuhan from January to May 2014. Real-time data were extracted from 11 weeks of GPS records collected in Wuhan from 5 May 2014 to 20 July 2014. Based on these data, we predicted link travel time for the period from 21 July 2014 to 25 July 2014. Experiments showed that our proposed spatiotemporal gradient–boosted regression tree model obtained better results than gradient boosting, random forest, or autoregressive integrated moving average approaches. Furthermore, these results indicate the advantages of our model for urban link travel time prediction.

  12. Critical analysis of the daylight saving time; Analisis critico al horario del verano

    Energy Technology Data Exchange (ETDEWEB)

    Romero Paredes Rubio, Hernando [Universidad Autonoma Metropolitana Ciudad-Ixtapalapa, Mexico, D.F., (Mexico)

    2001-07-01

    The critical analysis is presented as a synthesis of the problem untied since the implementation of the daylight saving time. The often related history is retaken to introduce the reader into the context of the causes of a such program. The geometric aspect of the solar trajectories is discussed and the length of the day as a function of the latitude and the time of the year to have technical elements for the time displacement in a certain region. The technical implementation of the daylight saving time based on three elements is justified: time of dawn and the decline (length of the day), national economic motivation and tourism industry. Stands out that although the daylight saving time schedule has a set of social and economic benefits it is not centered in the individual but in the society as a whole. The errors in handling the information and the misinformation are pointed out as the main causes of the controversy, the discord and the political manipulation of competing groups. [Spanish] El analisis critico se presenta como una sintesis del problema desatado desde la implementacion del horario de verano. La historia muchas veces contada se retoma para introducir al lector en el contexto de las causas de un tal programa. Se discute el aspecto geometrico de las trayectorias solares y la longitud del dia como una funcion de la latitud y de la epoca del ano para tener elementos tecnicos para el desplazamiento horario en una region determinada. Se justifica la implementacion tecnica del horario de verano en funcion de tres elementos: hora de alba y del ocaso (longitud del dia), motivacion economica nacional e industria turistica. Se destaca que si bien el horario de verano tiene un conjunto de beneficios sociales y economicos no se centra en el individuo sino en la sociedad en su conjunto. Se senalan los errores de manejo de la informacion y la desinformacion como los principales causantes de la polemica, el desacuerdo y la manipulacion politica de grupos

  13. A Quantitative Analysis of the Relationship Between Radiation Therapy Use and Travel Time

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Emma; Santibáñez, Pablo [British Columbia Cancer Agency, Vancouver, British Columbia (Canada); Puterman, Martin L. [Sauder School of Business, University of British Columbia, Vancouver, British Columbia (Canada); Weber, Leah; Ma, Xiang [British Columbia Cancer Agency, Vancouver, British Columbia (Canada); Sauré, Antoine [Sauder School of Business, University of British Columbia, Vancouver, British Columbia (Canada); Olivotto, Ivo A.; Halperin, Ross; French, John [British Columbia Cancer Agency, Vancouver, British Columbia (Canada); Tyldesley, Scott, E-mail: styldesl@bccancer.bc.ca [British Columbia Cancer Agency, Vancouver, British Columbia (Canada)

    2015-11-01

    Purpose: To model and quantify the relationship between radiation therapy (RT) use and travel time to RT services. Methods and Materials: Population-based registries and databases were used to identify both incident cancer patient and patients receiving RT within 1 year of diagnosis (RT1y) in British Columbia, Canada, between 1992 and 2011. The effects of age, gender, diagnosis year, income, prevailing wait time, and travel duration for RT on RT1y were assessed. Significant factors from univariate analyses were included in a multivariable logistic regression model. The shape of the travel time–RT1y curve was represented by generalized additive and segmented regression models. Analyses were conducted for breast, lung, and genitourinary cancer separately and for all cancer sites combined. Results: After adjustment for age, gender, diagnosis year, income, and prevailing wait times, increasing travel time to the closest RT facility had a negative impact RT1y. The shape of the travel time–RT1y curve varied with cancer type. For breast cancer, the odds of RT1y were constant for the first 2 driving hours and decreased at 17% per hour thereafter. For lung cancer, the odds of RT1y decreased by 16% after 20 minutes and then decreased at 6% per hour. Genitourinary cancer RT1y was relatively independent of travel time. For all cancer sites combined, the odds of RT1y were constant within the first 2 driving hours and decreased at 7% per hour thereafter. Conclusions: Travel time to receive RT has a different impact on RT1y for different tumor sites. The results provide evidence-based insights for the configuration of catchment areas for new and existing cancer centers providing RT.

  14. A Quantitative Analysis of the Relationship Between Radiation Therapy Use and Travel Time

    International Nuclear Information System (INIS)

    Liu, Emma; Santibáñez, Pablo; Puterman, Martin L.; Weber, Leah; Ma, Xiang; Sauré, Antoine; Olivotto, Ivo A.; Halperin, Ross; French, John; Tyldesley, Scott

    2015-01-01

    Purpose: To model and quantify the relationship between radiation therapy (RT) use and travel time to RT services. Methods and Materials: Population-based registries and databases were used to identify both incident cancer patient and patients receiving RT within 1 year of diagnosis (RT1y) in British Columbia, Canada, between 1992 and 2011. The effects of age, gender, diagnosis year, income, prevailing wait time, and travel duration for RT on RT1y were assessed. Significant factors from univariate analyses were included in a multivariable logistic regression model. The shape of the travel time–RT1y curve was represented by generalized additive and segmented regression models. Analyses were conducted for breast, lung, and genitourinary cancer separately and for all cancer sites combined. Results: After adjustment for age, gender, diagnosis year, income, and prevailing wait times, increasing travel time to the closest RT facility had a negative impact RT1y. The shape of the travel time–RT1y curve varied with cancer type. For breast cancer, the odds of RT1y were constant for the first 2 driving hours and decreased at 17% per hour thereafter. For lung cancer, the odds of RT1y decreased by 16% after 20 minutes and then decreased at 6% per hour. Genitourinary cancer RT1y was relatively independent of travel time. For all cancer sites combined, the odds of RT1y were constant within the first 2 driving hours and decreased at 7% per hour thereafter. Conclusions: Travel time to receive RT has a different impact on RT1y for different tumor sites. The results provide evidence-based insights for the configuration of catchment areas for new and existing cancer centers providing RT.

  15. [Travel time and distances to Norwegian out-of-hours casualty clinics].

    Science.gov (United States)

    Raknes, Guttorm; Morken, Tone; Hunskår, Steinar

    2014-11-01

    Geographical factors have an impact on the utilisation of out-of-hours services. In this study we have investigated the travel distance to out-of-hours casualty clinics in Norwegian municipalities in 2011 and the number of municipalities covered by the proposed recommendations for secondary on-call arrangements due to long distances. We estimated the average maximum travel times and distances in Norwegian municipalities using a postcode-based method. Separate analyses were performed for municipalities with a single, permanently located casualty clinic. Altogether 417 out of 430 municipalities were included. We present the median value of the maximum travel times and distances for the included municipalities. The median maximum average travel distance for the municipalities was 19 km. The median maximum average travel time was 22 minutes. In 40 of the municipalities (10 %) the median maximum average travel time exceeded 60 minutes, and in 97 municipalities (23 %) the median maximum average travel time exceeded 40 minutes. The population of these groups comprised 2 % and 5 % of the country's total population respectively. For municipalities with permanent emergency facilities(N = 316), the median average flight time 16 minutes and median average distance 13 km.. In many municipalities, the inhabitants have a long average journey to out-of-hours emergency health services, but seen as a whole, the inhabitants of these municipalities account for a very small proportion of the Norwegian population. The results indicate that the proposed recommendations for secondary on-call duty based on long distances apply to only a small number of inhabitants. The recommendations should therefore be adjusted and reformulated to become more relevant.

  16. The impact of environmental policy instruments on the timing of adoption of energy-saving technologies

    International Nuclear Information System (INIS)

    van Soest, Daan P.

    2005-01-01

    One of the main considerations in designing environmental policy is the impact of policy instruments on the timing of firms' investment decisions with respect to energy-saving technologies. This paper analyzes the impact of environmental taxes and quotas on the timing of adoption when (i) the rate at which new, improved energy-efficient technologies become available, is uncertain, and (ii) the investment decision is (at least partially) irreversible. We find that neither policy instrument is unambiguously preferred to the other when it comes to stimulating early adoption of new technologies. (author) (Environmental taxation; Command-and-control instruments; Dynamic efficiency; Stochasticity)

  17. Time to propagate green building construction concept for saving precious resources sustainable development

    International Nuclear Information System (INIS)

    Ali, Z.

    2005-01-01

    At present, we are constructing houses and buildings without giving any consideration to consumption of resources at the time of construction and consumption of resources for the use of such houses or buildings. ; Although green is our color but we are doing little about green building. Time has now come to propagate Green Building Construction Concepts in order to save our precious resources. The paper deals with dire need of awareness about conservation of water, conservation of energy, use of local materials, use of natural materials, etc. (author)

  18. Investigation of Bicycle Travel Time Estimation Using Bluetooth Sensors for Low Sampling Rates

    Directory of Open Access Journals (Sweden)

    Zhenyu Mei

    2014-10-01

    Full Text Available Filtering the data for bicycle travel time using Bluetooth sensors is crucial to the estimation of link travel times on a corridor. The current paper describes an adaptive filtering algorithm for estimating bicycle travel times using Bluetooth data, with consideration of low sampling rates. The data for bicycle travel time using Bluetooth sensors has two characteristics. First, the bicycle flow contains stable and unstable conditions. Second, the collected data have low sampling rates (less than 1%. To avoid erroneous inference, filters are introduced to “purify” multiple time series. The valid data are identified within a dynamically varying validity window with the use of a robust data-filtering procedure. The size of the validity window varies based on the number of preceding sampling intervals without a Bluetooth record. Applications of the proposed algorithm to the dataset from Genshan East Road and Moganshan Road in Hangzhou demonstrate its ability to track typical variations in bicycle travel time efficiently, while suppressing high frequency noise signals.

  19. Assessment of Smolt Condition for Travel Time Analysis, 1991-1992 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Maule, Alec G.; Beeman, John W.; Schrock, Robin M. (Seattle National Fishery Research Center, Columbia River Field Station, Cook, WA)

    1994-05-01

    Regression techniques were used to determine the effects of several biotic and abiotic variables on the migration rates of juvenile spring chinook salmon and steelhead in the Columbia and Snake rivers. Comparisons of the effects of river flow and smoltification, assessed using gill Na{sup +}-K{sup +} ATPase activity, were of primary interest. Day of the year, water temperature, change in flow, condition factor, and fork length were also considered as independent variables. Groups of fish were sampled to assess smoltification 2-3 times per week during the spring outmigrations during 1989-1992. These groups were assumed to be representative of other fish which were PIT-tagged and released as a part of the Smolt Monitoring Program in the Columbia Basin. River flow, gill ATPase activity, condition factor, water temperature, and change in flow were significant variables in regressions predicting the time for juvenile spring chinook salmon to travel between specific points (travel time), whereas river flow was the only significant contributor to models describing travel times of steelhead. Predicted travel times of wild steelhead were shorter than those of hatchery steelhead. River flow was the only variable common to all regression equations. Based on the characteristic, changes in river flow would be the most logical means to decrease travel times of both juvenile spring chinook salmon and steelhead in the Columbia and Snake rivers.

  20. Ground-water travel time calculations for the potential nuclear repository site at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Younker, J.L.; Wilson, W.E.; Sinnock, S.

    1986-01-01

    In support of the US Department of Energy Nevada Nuclear Waste Storage Investigations Project, ground-water travel times were calculated for flow paths in both the saturated and unsaturated zones at Yucca Mountain, a potential site for a high-level radioactive waste repository in southern Nevada. The calculations were made through a combined effort by Science Applications International Corporation, Sandia National Laboratories, and the US Geological Survey. Travel times in the unsaturated zone were estimated by dividing the flow path length by the ground-water velocity, where velocities were obtained by dividing the vertical flux by the effective porosity of the rock types along assumed vertical flow paths. Saturated zone velocities were obtained by dividing the product of the bulk hydraulic conductivity and hydraulic gradient by the effective porosity. Total travel time over an EPA-established 5-km flow path was then calculated to be the sum of the travel times in the two parts of the flow path. Estimates of ground water fluxes and travel times are critical for evaluating the favorability of the Yucca Mountain site because they provide the basis for estimating the potential for radionuclides to reach the accessible environment within certain time limits

  1. Characterizing corridor-level travel time distributions based on stochastic flows and segment capacities

    Directory of Open Access Journals (Sweden)

    Hao Lei

    2015-12-01

    Full Text Available Trip travel time reliability is an important measure of transportation system performance and a key factor affecting travelers’ choices. This paper explores a method for estimating travel time distributions for corridors that contain multiple bottlenecks. A set of analytical equations are used to calculate the number of queued vehicles ahead of a probe vehicle and further capture many important factors affecting travel times: the prevailing congestion level, queue discharge rates at the bottlenecks, and flow rates associated with merges and diverges. Based on multiple random scenarios and a vector of arrival times, the lane-by-lane delay at each bottleneck along the corridor is recursively estimated to produce a route-level travel time distribution. The model incorporates stochastic variations of bottleneck capacity and demand and explains the travel time correlations between sequential links. Its data needs are the entering and exiting flow rates and a sense of the lane-by-lane distribution of traffic at each bottleneck. A detailed vehicle trajectory data-set from the Next Generation SIMulation (NGSIM project has been used to verify that the estimated distributions are valid, and the sources of estimation error are examined.

  2. A pilot study into the perception of unreliability of travel times using in-depth interviews

    NARCIS (Netherlands)

    Tseng, Y.-Y.; Verhoef, E.; de Jong, G.; Kouwenhoven, M.; van der Hoorn, T.

    2009-01-01

    Transport investments normally reduce travel times, but may also reduce unreliability. Conventional time gains can be evaluated in cost benefit analysis using standard values of time. For valuing reliability gains, however, no standard measures are readily available. The Dutch Ministry of Transport

  3. The impact of daylight saving time on electricity consumption: Evidence from southern Norway and Sweden

    International Nuclear Information System (INIS)

    Mirza, Faisal Mehmood; Bergland, Olvar

    2011-01-01

    This paper examines the impact of daylight saving time (DST) on electricity consumption in southern Norway and Sweden. As DST was implemented in both the countries in 1980, we do not have a clear counterfactual in the form of a control period to identify the impact of DST directly with before and after or with and without analysis. This problem in the study is resolved by using 'equivalent day normalization technique' to identify the impact of DST. The difference-in-difference (DID) average treatment effects model suggests an annual reduction of at least 1.0 percent in electricity consumption for both Norway and Sweden due to DST. The average annual electricity consumption reduction corresponding to DST effects equals 519 and 882 GWh for southern Norway and Sweden, resulting in an annual financial saving of 16.1 million Euros and 30.1 million Euros, respectively. The distribution of treatment effects across different hours of the day indicates a small but significant reduction in electricity consumption during the morning and a steep decline during the evening hours in both countries. - Highlights: → We assess the impact of DST on electricity consumption in southern Norway and Sweden. → DST reduces electricity consumption by 1.3 percent in both countries. → The impact is smaller during the morning hours but larger during evening hours. → Respective annual financial savings equal Euro 16.1 and 30.1 million for Norway and Sweden. → Average annual electricity savings equal 519 and 882 GWh for two countries, respectively.

  4. Effective Time Management: Surgery, Research, Service, Travel, Fitness, and Family

    Science.gov (United States)

    Porta, C. Rees; Anderson, Michael R.; Steele, Scott R.

    2013-01-01

    Over 1,500 years ago, the St. Benedictine Monks used planning and strict schedules to increase their productivity. Since then, surgeons have developed several different strategies to manage our time effectively. Finding a balance among career, family, and hobbies is essential for maintaining satisfaction and optimizing productivity. Several recurring themes throughout the medical literature offer potential solutions to help maximize the little time surgeons possess. In this article, we will explore some of the methods and strategies available to help surgeons minimize waste and make the most of the most precious commodity we have—our time. PMID:24436684

  5. Dye Tracer Tests to Determine Time-of-Travel in Iowa Streams, 1990-2006

    Science.gov (United States)

    Christiansen, Daniel E.

    2009-01-01

    Dye-tracing tests have been used by the U.S. Geological Survey, Iowa Water Science Center to determine the time-of-travel in selected Iowa streams from 1990-2006. Time-of-travel data are tabulated for 309 miles of stream reaches in four Iowa drainage basins: the Des Moines, Raccoon, Cedar, and Turkey Rivers. Time-of-travel was estimated in the Des Moines River, Fourmile Creek, North Raccoon River, Raccoon River, Cedar River, and Roberts Creek. Estimation of time-of-travel is important for environmental studies and in determining fate of agricultural constituents and chemical movement through a waterway. The stream reaches range in length from slightly more than 5 miles on Fourmile Creek, to more than 137 miles on the North Raccoon River. The travel times during the dye-tracer tests ranged from 7.5 hours on Fourmile Creek to as long as 200 hours on Roberts Creek; velocities ranged from less than 4.50 feet per minute on Roberts Creek to more than 113 feet per minute on the Cedar River.

  6. Time-Of-Travel Tool Protects Drinking Water

    Science.gov (United States)

    The Lower Susquehanna Source Water Protection (SWP) Partnership utilizes the Incident Command Tool for Drinking Water Protection (ICWater) to support the Pennsylvania Department of Environmental Protection (PADEP) with real-time spill tracking information.

  7. Pn seismic wave travel time at the Semipalatinsk Test Site - Borovoe seismic station trace

    International Nuclear Information System (INIS)

    An, V.A.; Kaazik, P.B.; Ovchinnikov, V.M.

    2001-01-01

    This paper preparation involved 160 explosions at the Degelen Site conducted in 1961-1989 and 89 explosions at the Balapan Site conducted in 1968-1989. Pn wave travel time was tied to the sea level in accordance with velocity characteristics of the explosion hypocenter medium; and to average epicentral distance for every site basing on their local travel time curves of Pn wave relative to Borovoe station. Maximum amplitude of mean-year travel times variations is 0.3-0.5 s as at the Nevada Test Site - Borovoe trace and Mirniy (Antarctica). However, the linear trend in contrast to previous traces has negative sign (0.08 s for Degelen and 0.1 s for Balapan). Thus, Pn wave velocity increases with calendar time. (author)

  8. Measurement of time of travel and dispersion in streams by dye tracing

    Science.gov (United States)

    Hubbard, E.F.; Kilpatrick, F.A.; Martens, L.A.; Wilson, J.F.

    1982-01-01

    The use of fluorescent dyes and tracing techniques provides a means for measuring the time-of-travel and dispersion characteristics of steady and gradually varied flow in streams. Measurements of the dispersion and concentration of dyes give insight into the behavior of soluble contaminants that may be introduced into a stream. This manual describes methods of measuring time of travel of water and waterborne solutes by dye tracing. The fluorescent dyes, measuring equipment used, and the field and laboratory procedures are also described. Methods of analysis and presentation to illustrate time-oftravel and dispersion characteristics of streams are provided.

  9. Effects of Daylight Saving Time changes on stock market volatility: a reply.

    Science.gov (United States)

    Berument, Hakan; Dogan, Nukhet

    2011-12-01

    There is a rich array of evidence that suggests that changes in sleeping patterns affect an individual's decision-making processes. A nationwide sleeping-pattern change happens twice a year when the Daylight Saving Time (DST) change occurs. Kamstra, Kramer, and Levi argued in 2000 that a DST change lowers stock market returns. This study presents evidence that DST changes affect the relationship between stock market return and volatility. Empirical evidence suggests that the positive relationship between return and volatility becomes negative on the Mondays following DST changes.

  10. Application of Google-based Data for Travel Time Analysis: Kaunas City Case Study

    Directory of Open Access Journals (Sweden)

    Vytautas Dumbliauskas

    2017-12-01

    Full Text Available Recently, new traffic data sources have emerged raising new challenges and opportunities when applying novel methodologies. The purpose of this research is to analyse car travel time data collected from smartphones by Google Company. Geographic information system (GIS tools and Python programming language were employed in this study to establish the initial framework as well as to automatically extract, analyse, and visualize data. The analysis resulted in the calculation of travel time fluctuation during the day, calculation of travel time variability and estimation of origin-destination (OD skim matrices. Furthermore, we accomplished the accessibility analysis and provided recommendations for further research.

  11. Assessment of Smolt Condition for Travel Time Analysis Project, 1987-1997 Project Review.

    Energy Technology Data Exchange (ETDEWEB)

    Schrock, Robin M.; Hans, Karen M.; Beeman, John W. [US Geological Survey, Western Fisheries Research Center, Columbia River Research Laboratory, Cook, WA

    1997-12-01

    The assessment of Smolt Condition for Travel Time Analysis Project (Bonneville Power Administration Project 87-401) monitored attributes of salmonid smolt physiology in the Columbia and Snake River basins from 1987 to 1997, under the Northwest Power Planning Council Fish and Wildlife Program, in cooperation with the Smolt Monitoring Program of the Fish Passage Center. The primary goal of the project was to investigate the physiological development of juvenile salmonids related to migration rates. The assumption was made that the level of smolt development, interacting with environmental factos such as flow, would be reflected in travel times. The Fish Passage Center applied the physiological measurements of smolt condition to Water Budget management, to regulate flows so as to decrease travel time and increase survival.

  12. Approaching the brachistochrone using inclined planes—striving for shortest or equal travelling times

    Science.gov (United States)

    Theilmann, Florian

    2017-01-01

    The classical brachistochrone problem asks for the path on which a mobile point M just driven by its own gravity will travel in the shortest possible time between two given points A and B. The resulting curve, the cycloid, will also be the tautochrone curve, i.e. the travelling time of the mobile point will not depend on its starting position. We discuss three similar problems of increasing complexity that restrict the motion to inclined planes. Without using calculus we derive the respective optimal geometry and compare the theoretical values to measured travelling times. The observed discrepancies are quantitatively modelled by including angular motion and friction. We also investigate the correspondence between the original problem and our setups. The topic provides a conceptually simple yet non-trivial problem setting inviting for problem based learning and complex learning activities such as planing suitable experiments or modelling the relevant kinematics.

  13. Measuring cross-border travel times for freight : Otay Mesa international border crossing.

    Science.gov (United States)

    2010-09-01

    Cross border movement of people and goods is a vital part of the North American economy. : Accurate real-time data on travel times along the US-Mexico border can help generate a range : of tangible benefits covering improved operations and security, ...

  14. Model-based Integration of Past & Future in TimeTravel

    DEFF Research Database (Denmark)

    Khalefa, Mohamed E.; Fischer, Ulrike; Pedersen, Torben Bach

    2012-01-01

    it to answer approximate and exact queries. TimeTravel is implemented into PostgreSQL, thus achieving complete user transparency at the query level. In the demo, we show the easy building of a hierarchical model index for a real-world time series and the effect of varying the error guarantees on the speed up...

  15. Access to destinations : arterial data acquisition and network-wide travel time estimation (phase II).

    Science.gov (United States)

    2010-03-01

    The objectives of this project were to (a) produce historic estimates of travel times on Twin-Cities arterials : for 1995 and 2005, and (b) develop an initial architecture and database that could, in the future, produce timely : estimates of arterial...

  16. Polynomial time approximation schemes for the traveling repairman and other minimum latency problems

    NARCIS (Netherlands)

    R.A. Sitters (René); C. Chekuri

    2014-01-01

    htmlabstractWe give a polynomial time, (1 + ∊)-approximation algorithm for the traveling repairman problem (TRP) in the Euclidean plane, on weighted planar graphs, and on weighted trees. This improves on the known quasi-polynomial time approximation schemes for these problems. The algorithm is based

  17. Polynomial time approximation schemes for the traveling repairman and other minimum latency problems

    NARCIS (Netherlands)

    R.A. Sitters (René)

    2013-01-01

    htmlabstractWe give a polynomial time, (1 + \\epsilon)-approximation algorithm for the traveling repairman problem (TRP) in the Euclidean plane, on weighted planar graphs, and on weighted trees. This improves on the known quasi-polynomial time approximation schemes for these problems. The algorithm

  18. Impacts of residence time during storage on potential of water saving for grey water recycling system.

    Science.gov (United States)

    Liu, S; Butler, D; Memon, F A; Makropoulos, C; Avery, L; Jefferson, B

    2010-01-01

    Grey water recycling has been generally accepted and is about to move into practice in terms of sustainable development. Previous research has revealed the bacteria re-growth in grey water and reclaimed municipal water during storage. However, in most present grey water recycling practices, impacts of water quality changes during storage on the system's performance and design regulation have not been addressed. In this paper, performance of a constructed wetland based grey water recycling system was analysed by taking the constraint of residence time during storage into account using an object based household water cycle model. Two indicators, water saving efficiency (WSE) and residence time index (RTI), are employed to reflect the system's performance and residence time during storage respectively. Results show that WSE and RTI change with storage tank volumes oppositely. As both high WSE and RTI cannot be achieved simultaneously, it is concluded that in order to achieve the most cost-effective and safe solution, systems with both small grey and green tanks are needed, whilst accepting that only relatively modest water saving efficiency targets can be achieved. Higher efficiencies will only be practicable if water quality deterioration in the green water tank can be prevented by some means (e.g. disinfection).

  19. Riding the Electricity Market as an Energy Management Strategy: Savings from Real-Time Pricing

    Energy Technology Data Exchange (ETDEWEB)

    Chiles, Thomas; Shutika, Kenneth; Coleman, Philip

    2018-03-13

    Dynamic pricing of electricity, in which retail prices facing customers are responsive to changes in the underlying wholesale markets, represents a step towards economic efficiency in that customers get exposed to some or all of the costs facing wholesale market players. But what do customers who opt for this greater exposure – available in the roughly 15 “de-regulated” states, as well as, to some extent, from some regulated utilities – get in return for their risks? The U.S. General Services Administration (GSA) took a retrospective eight-year look at what the savings would have been had they let the loads for which they purchase electricity in the Washington, DC area buy electricity on the real-time pricing (RTP) market – the dynamic pricing option with the highest risk – as opposed to the strategy they chose in actuality, which was fixing flat prices with 3rd-party providers. We found that opting for RTP for the eight years of the study (2005 through 2012) would have resulted in 17% savings, or almost a quarter of a billion dollars, relative to GSA’s actual prices from the 3rd-party suppliers. This is particularly astonishing given that GSA appeared to have timed the market well during the study period, consistently beating the standard offer products provided by the distribution utilities. The issue of budgetary predictability poses an obstacle for customers (especially government ones) considering RTP and, to a lesser extent, other dynamic pricing options. Indeed, GSA would have lost money with RTP in two of the eight years, one of them substantially. But the magnitude of the savings is indisputably compelling and, even if it may be somewhat aberrational due to high congestion in the DC market, begs consideration by large electricity users currently paying to “lock in” fixed flat prices.

  20. CMEs' Speed, Travel Time, and Temperature: A Thermodynamic Approach

    Science.gov (United States)

    Durand-Manterola, Hector J.; Flandes, Alberto; Rivera, Ana Leonor; Lara, Alejandro; Niembro, Tatiana

    2017-12-01

    Due to their important role in space weather, coronal mass ejections or CMEs have been thoroughly studied in order to forecast their speed and transit time from the Sun to the Earth. We present a thermodynamic analytical model that describes the dynamics of CMEs. The thermodynamic approach has some advantages with respect to the hydrodynamic approach. First, it deals with the energy involved, which is a scalar quantity. Second, one may calculate the work done by the different forces separately and sum all contributions to determine the changes in speed, which simplifies the problem and allows us to obtain fully rigorous results. Our model considers the drag force, which dominates the dynamics of CMEs and the solar gravitational force, which has a much smaller effect, but it is, still, relevant enough to be considered. We derive an explicit analytical expression for the speed of CMEs in terms of its most relevant parameters and obtain an analytical expression for the CME temperature. The model is tested with a CME observed at three different heliocentric distances with three different spacecraft (SOHO, ACE, and Ulysses); also, with a set of 11 CMEs observed with the SOHO, Wind, and ACE spacecraft and, finally, with two events observed with the STEREO spacecraft. In all cases, we have a consistent agreement between the theoretical and the observed speeds and transit times. Additionally, for the set of 11 events, we estimate their temperatures at their departure position from their temperatures measured near the orbit of the Earth.

  1. LHC 2008 talks Peut-on voyager dans le temps? (Is time travel possible?)

    CERN Multimedia

    2008-01-01

    Scientific magazines (and sometimes even scientists themselves) regularly talk about the possibility of travelling through time. It has also been the subject of many science-fiction novels. We will first discuss what we mean when we talk about time travel, then explain what contemporary physics has to say about it. Thursday, 12 June 2008 at 8.00 p.m. Peut-on voyager dans le temps ? Etienne Klein Physicist at CEA and Doctor of Philosophy of Science The Globe, first floor No specialist knowledge required. Entrance free. http://www.cern.ch/globe

  2. Reliable Rescue Routing Optimization for Urban Emergency Logistics under Travel Time Uncertainty

    Directory of Open Access Journals (Sweden)

    Qiuping Li

    2018-02-01

    Full Text Available The reliability of rescue routes is critical for urban emergency logistics during disasters. However, studies on reliable rescue routing under stochastic networks are still rare. This paper proposes a multiobjective rescue routing model for urban emergency logistics under travel time reliability. A hybrid metaheuristic integrating ant colony optimization (ACO and tabu search (TS was designed to solve the model. An experiment optimizing rescue routing plans under a real urban storm event, was carried out to validate the proposed model. The experimental results showed how our approach can improve rescue efficiency with high travel time reliability.

  3. Use of videoconferencing in Wales to reduce carbon dioxide emissions, travel costs and time.

    Science.gov (United States)

    Lewis, Delyth; Tranter, Glynis; Axford, Alan T

    2009-01-01

    In September 2005 a telemedicine service was started to assist multidisciplinary teams in Wales to improve cancer services. In October 2006 and October 2007 users of videoconferencing equipment at one site completed questionnaires. During October 2006 a total of 18,000 km of car travel were avoided, equivalent to 1696 kg of CO(2) emission. During October 2007 a total of 20,800 km of car travel were avoided, equivalent to 2590 kg of CO(2) emission. We estimate that 48 trees would take a year to absorb that quantity of CO(2). The results of the surveys show that exploiting telemedicine makes better use of staff time, reduces the time spent travelling and assists in reducing climate change by limiting the emissions of CO(2).

  4. Electron and VLF travel time differences for wave-particle interactions at L=4: Pt. 2

    International Nuclear Information System (INIS)

    Rash, J.P.S.; Scourfield, M.W.J.; Dougherty, M.K.

    1984-01-01

    The cyclotron resonance or gyroresonance interaction has been widely invoked as a generation mechanism for discrete VLF emissions and plasmaspheric hiss. This interaction involves electrons and VLF waves travelling in opposite directions along a geomagnetic field line. We examine, for an interaction region in the equatorial plane at L=4, the energy of the resonant electrons as a function of VLF wave frequency and ambient equatorial electron density. Then for two different spatial configurations of the interaction and two standard plasma distribution models we examine the difference in travel times to a ground-based observer in the Southern hemisphere for the electrons and waves taking part in the interaction. This difference in travel times is shown as a function of VLF wave frequency and equatorial electron density. The results, and their significance for observations of auroral electrons and VLF at Sanae, Antarctica, are discussed and compared with similar results for the Cerenkov interaction discussed in an earlier paper

  5. Estimating time and travel costs incurred in clinic based screening: flexible sigmoidoscopy screening for colorectal cancer.

    Science.gov (United States)

    Frew, E; Wolstenholme, J L; Atkin, W; Whynes, D K

    1999-01-01

    To identify the characteristics of mode of travel to screening clinics; to estimate the time and travel costs incurred in attending; to investigate whether such costs are likely to bias screening compliance. Twelve centres in the trial of flexible sigmoidoscopy screening for colorectal cancer, drawn from across Great Britain. Analysis of 3525 questionnaires completed by screening subjects while attending clinics. Information supplied included sociodemographic characteristics, modes of travel, expenses, activities foregone owing to attendance, and details of companions. More than 80% of subjects arrived at the clinics by car, and about two thirds were accompanied. On average, the clinic visit involved a 14.4 mile (22.8 km) round trip, requiring 130 minutes. Mean travel costs amounted to 6.10 Pounds per subject. The mean gross direct non-medical and indirect cost per subject amounted to 16.90 Pounds, and the mean overall gross cost per attendance was 22.40 Pounds. Compared with the Great Britain population as a whole, non-manual classes were more strongly represented, and the self employed less strongly represented, among the attendees. In relation to direct medical costs, the time and travel costs of clinic based screening can be substantial, may influence the overall cost effectiveness of a screening programme, and may deter potential subjects from attending.

  6. The impact of the daylight saving time on electricity consumption-A case study from Jordan

    International Nuclear Information System (INIS)

    Awad Momani, Mohammad; Yatim, Baharudin; Ali, Mohd Alauddin Mohd

    2009-01-01

    The paper examines the impact of daylight saving time (DST) on electricity consumption in Jordan. Two types of analysis were done: the first analysis examines the impact of DST on the lighting loads based on a survey study made for residential and commercial sectors. The second examines the impact of DST on the over all electricity generation through analyzing the daily load curves (DLCs) before and after the DST onset and removal in 2000 and 2007. The results show that the application of DST during the year 2000 saves the electricity used for illumination by -0.73% but it increases the overall generation at the onset and removal of DST by 0.5% and 1.4% due to increase in the heating and cooling loads. The analysis of DLCs during the year 2007 shows similar effects as in the year 2000 except during the early morning period at the DST onset where DST decreases the demand during this time. The analysis shows that DST decreases the electricity demand at DST onset by 0.2% and increases it at DST removal by 0.3%. A possible decrease in the electricity consumption may take place if the DST is implemented from April to end of August.

  7. Dispersion and Travel Time of Dissolved and Floating Tracers in Urban Sewers

    Directory of Open Access Journals (Sweden)

    Istók Balázs

    2014-03-01

    Full Text Available Environmental impacts of oil spills affecting urban sewage networks can be eliminated if timely intervention is taken. The design of such actions requires knowledge of the transport of surface pollutants in open channels. In this study we investigated the travel time and dispersion of pollutants by means of tracer experiments in sewage networks and a creek. The travel time of surface tracers has been found to be significantly shorter than that of a bulk flow tracer. The ratio of the travel times of a bulk flow tracer and surface tracers agreed with the known correlations obtained for rivers. An increasing tendency in the ratio of travel times has been observed for increasing bulk flow velocity. A segment-wise dispersion model was implemented in the existing hydraulic model of a sewer system. The simulation results were compared with the experimental observations. The dispersion rate of the bulk flow tracer has been found to obey Taylor’s mixing theory for long channels and was more intensive than that of surface tracers in community sewage channels.

  8. 41 CFR 301-71.306 - Are there exceptions to collecting an advance at the time the employee files a travel claim?

    Science.gov (United States)

    2010-07-01

    ... collecting an advance at the time the employee files a travel claim? 301-71.306 Section 301-71.306 Public Contracts and Property Management Federal Travel Regulation System TEMPORARY DUTY (TDY) TRAVEL ALLOWANCES AGENCY RESPONSIBILITIES 71-AGENCY TRAVEL ACCOUNTABILITY REQUIREMENTS Accounting for Travel Advances § 301...

  9. Do freight transport time savings translate to benefit for transport consuming companies?

    Directory of Open Access Journals (Sweden)

    Evangelos Sambracos

    2017-05-01

    Full Text Available It is common practice in Benefit - Cost analysis to consider freight transport time savings (FTTS as a benefit for both transport producing and consuming companies. While transportation projects and policies resulting in FTTS are expected to have a positive effect on carriers’ performance reducing time related transport costs and improving service, this is not always the case for the demand side of the transport market. Using System Dynamics in order to model the internal supply chain of a transport using company and simulate several scenarios, we argue that FTTS do not necessarily translate to benefit for shippers, but their effect depends strongly on the structure of the company’s decision making process.

  10. Variable elasticity of substituition in a discrete time Solow–Swan growth model with differential saving

    International Nuclear Information System (INIS)

    Brianzoni, Serena; Mammana, Cristiana; Michetti, Elisabetta

    2012-01-01

    Highlights: ► One dimensional piecewise smooth map: border collision bifurcations. ► Numerical simulations: complex dynamics. ► Ves production function in the solow–swan growth model and comparison with the ces production function. - Abstract: We study the dynamics shown by the discrete time neoclassical one-sector growth model with differential savings as in Bohm and Kaas while assuming VES production function in the form given by Revankar . It is shown that the model can exhibit unbounded endogenous growth despite the absence of exogenous technical change and the presence of non-reproducible factors if the elasticity of substitution is greater than one. We then consider parameters range related to non-trivial dynamics (i.e. the elasticity of substitution in less than one and shareholders save more than workers) and we focus on local and global bifurcations causing the transition to more and more complex asymptotic dynamics. In particular, as our map is non-differentiable in a subset of the states space, we show that border collision bifurcations occur. Several numerical simulations support the analysis.

  11. Estimating Reaction Rate Coefficients Within a Travel-Time Modeling Framework

    Energy Technology Data Exchange (ETDEWEB)

    Gong, R [Georgia Institute of Technology; Lu, C [Georgia Institute of Technology; Luo, Jian [Georgia Institute of Technology; Wu, Wei-min [Stanford University; Cheng, H. [Stanford University; Criddle, Craig [Stanford University; Kitanidis, Peter K. [Stanford University; Gu, Baohua [ORNL; Watson, David B [ORNL; Jardine, Philip M [ORNL; Brooks, Scott C [ORNL

    2011-03-01

    A generalized, efficient, and practical approach based on the travel-time modeling framework is developed to estimate in situ reaction rate coefficients for groundwater remediation in heterogeneous aquifers. The required information for this approach can be obtained by conducting tracer tests with injection of a mixture of conservative and reactive tracers and measurements of both breakthrough curves (BTCs). The conservative BTC is used to infer the travel-time distribution from the injection point to the observation point. For advection-dominant reactive transport with well-mixed reactive species and a constant travel-time distribution, the reactive BTC is obtained by integrating the solutions to advective-reactive transport over the entire travel-time distribution, and then is used in optimization to determine the in situ reaction rate coefficients. By directly working on the conservative and reactive BTCs, this approach avoids costly aquifer characterization and improves the estimation for transport in heterogeneous aquifers which may not be sufficiently described by traditional mechanistic transport models with constant transport parameters. Simplified schemes are proposed for reactive transport with zero-, first-, nth-order, and Michaelis-Menten reactions. The proposed approach is validated by a reactive transport case in a two-dimensional synthetic heterogeneous aquifer and a field-scale bioremediation experiment conducted at Oak Ridge, Tennessee. The field application indicates that ethanol degradation for U(VI)-bioremediation is better approximated by zero-order reaction kinetics than first-order reaction kinetics.

  12. Minimizing the Time of Travel for a Long-distance Train Journey: A ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 8; Issue 10. Minimizing the Time of Travel for a Long-distance Train Journey: A Model. S N Maitra. Classroom Volume 8 Issue 10 October 2003 pp 85-86. Fulltext. Click here to view fulltext PDF. Permanent link:

  13. Data Fusion Based Hybrid Approach for the Estimation of Urban Arterial Travel Time

    Directory of Open Access Journals (Sweden)

    S. P. Anusha

    2012-01-01

    Full Text Available Travel time estimation in urban arterials is challenging compared to freeways and multilane highways. This becomes more complex under Indian conditions due to the additional issues related to heterogeneity, lack of lane discipline, and difficulties in data availability. The fact that most of the urban arterials in India do not employ automatic detectors demands the need for an effective, yet less data intensive way of estimating travel time. An attempt has been made in this direction to estimate total travel time in an urban road stretch using the location based flow data and sparse travel time data obtained using GPS equipped probe vehicles. Three approaches are presented and compared in this study: (1 a combination of input-output analysis for mid-blocks and Highway Capacity Manual (HCM based delay calculation at signals named as base method, (2 data fusion approach which employs Kalman filtering technique (nonhybrid method, and (3 a hybrid data fusion HCM (hybrid DF-HCM method. Data collected from a stretch of roadway in Chennai, India was used for the corroboration. Simulated data were also used for further validation. The results showed that when data quality is assured (simulated data the base method performs better. However, in real field situations, hybrid DF-HCM method outperformed the other methods.

  14. Assessment of Smolt Condition for Travel Time Analysis, 1993-1994 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Schrock, Robin M; Beeman, John W; VanderKooi, Scott P [US Geological Survey, Western Fisheries Research Center, Columbia River Research Laboratory, Cook, WA

    1999-02-01

    The assessment of smolt condition for travel time analysis (ASCTTA) project provided information on the level of smoltification in Columbia River hatchery and wild salmonid stocks to the Fish Passage Center (FPC), for the primary purpose of in-river management of flows.

  15. Modeling Travel Time Reliability of Road Network Considering Connected Vehicle Guidance Characteristics Indexes

    Directory of Open Access Journals (Sweden)

    Jiangfeng Wang

    2017-01-01

    Full Text Available Travel time reliability (TTR is one of the important indexes for effectively evaluating the performance of road network, and TTR can effectively be improved using the real-time traffic guidance information. Compared with traditional traffic guidance, connected vehicle (CV guidance can provide travelers with more timely and accurate travel information, which can further improve the travel efficiency of road network. Five CV characteristics indexes are selected as explanatory variables including the Congestion Level (CL, Penetration Rate (PR, Compliance Rate (CR, release Delay Time (DT, and Following Rate (FR. Based on the five explanatory variables, a TTR model is proposed using the multilogistic regression method, and the prediction accuracy and the impact of characteristics indexes on TTR are analyzed using a CV guidance scenario. The simulation results indicate that 80% of the RMSE is concentrated within the interval of 0 to 0.0412. The correlation analysis of characteristics indexes shows that the influence of CL, PR, CR, and DT on the TTR is significant. PR and CR have a positive effect on TTR, and the average improvement rate is about 77.03% and 73.20% with the increase of PR and CR, respectively, while CL and DT have a negative effect on TTR, and TTR decreases by 31.21% with the increase of DT from 0 to 180 s.

  16. Travel Time Model of Left-Turning Vehicles at Signalized Intersection

    Directory of Open Access Journals (Sweden)

    Leng Jun-qiang

    2012-01-01

    Full Text Available The travel time of left-turning vehicles at signalized intersection was discussed. Under the assumption that the opposing through vehicles headway follows M3 distribution, the travel time model was established on the basis of gap theory and queue theory. Comparison was done with the common model based on the assumption that the opposing through vehicles headway follows negative exponential distribution. The results show that the model in this paper has stronger applicability and its most relative error is less than 15%. In addition, the sensitivity analysis was done. The results show that the opposing through flow rate has significant impact on travel time. The impact of left-turning flow rate and following headway is light when the opposing through flow rate is small, the threshold is about 0.18 veh/s. The model established in this paper can well calculate travel time of left-turning vehicles at intersection, and the methodology may provide reference to other occasions.

  17. 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.

  18. Fire behavior simulation in Mediterranean forests using the minimum travel time algorithm

    Science.gov (United States)

    Kostas Kalabokidis; Palaiologos Palaiologou; Mark A. Finney

    2014-01-01

    Recent large wildfires in Greece exemplify the need for pre-fire burn probability assessment and possible landscape fire flow estimation to enhance fire planning and resource allocation. The Minimum Travel Time (MTT) algorithm, incorporated as FlamMap's version five module, provide valuable fire behavior functions, while enabling multi-core utilization for the...

  19. Compensation for the distortion in satellite laser range predictions due to varying pulse travel times

    Science.gov (United States)

    Paunonen, Matti

    1993-01-01

    A method for compensating for the effect of the varying travel time of a transmitted laser pulse to a satellite is described. The 'observed minus predicted' range differences then appear to be linear, which makes data screening or use in range gating more effective.

  20. Involuntary Mental Time Travel and Its Effect on Prospective Teachers' Situational Intrinsic Motivations

    Science.gov (United States)

    Eren, Altay

    2010-01-01

    Recent cognitive psychological research has argued that involuntary mental time travel is an important individual difference variable that has the potential to affect an individual's motivation. However, this issue has not been empirically investigated in educational settings such as teacher education. Therefore, this study aimed to explore the…

  1. The effect of centralization of health care services on travel time and its equality.

    Science.gov (United States)

    Kobayashi, Daisuke; Otsubo, Tetsuya; Imanaka, Yuichi

    2015-03-01

    To analyze the regional variations in travel time between patient residences and medical facilities for the treatment of ischemic heart disease and breast cancer, and to simulate the effects of health care services centralization on travel time and equality of access. We used medical insurance claims data for inpatients and outpatients for the two target diseases that had been filed between September 2008 and May 2009 in Kyoto Prefecture, Japan. Using a geographical information system, patient travel times were calculated based on the driving distance between patient residences and hospitals via highways and toll roads. Locations of residences and hospital locations were identified using postal codes. We then conducted a simulation analysis of centralization of health care services to designated regional core hospitals. The simulated changes in potential spatial access to care were examined. Inequalities in access to care were examined using Gini coefficients, which ranged from 0.4109 to 0.4574. Simulations of health care services centralization showed reduced travel time for most patients and overall improvements in equality of access, except in breast cancer outpatients. Our findings may contribute to the decision-making process in policies aimed at improving the potential spatial access to health care services. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  2. Monostable traveling waves for a time-periodic and delayed nonlocal reaction-diffusion equation

    Science.gov (United States)

    Li, Panxiao; Wu, Shi-Liang

    2018-04-01

    This paper is concerned with a time-periodic and delayed nonlocal reaction-diffusion population model with monostable nonlinearity. Under quasi-monotone or non-quasi-monotone assumptions, it is known that there exists a critical wave speed c_*>0 such that a periodic traveling wave exists if and only if the wave speed is above c_*. In this paper, we first prove the uniqueness of non-critical periodic traveling waves regardless of whether the model is quasi-monotone or not. Further, in the quasi-monotone case, we establish the exponential stability of non-critical periodic traveling fronts. Finally, we illustrate the main results by discussing two types of death and birth functions arising from population biology.

  3. Travel medicine

    Science.gov (United States)

    Aw, Brian; Boraston, Suni; Botten, David; Cherniwchan, Darin; Fazal, Hyder; Kelton, Timothy; Libman, Michael; Saldanha, Colin; Scappatura, Philip; Stowe, Brian

    2014-01-01

    Abstract Objective To define the practice of travel medicine, provide the basics of a comprehensive pretravel consultation for international travelers, and assist in identifying patients who might require referral to travel medicine professionals. Sources of information Guidelines and recommendations on travel medicine and travel-related illnesses by national and international travel health authorities were reviewed. MEDLINE and EMBASE searches for related literature were also performed. Main message Travel medicine is a highly dynamic specialty that focuses on pretravel preventive care. A comprehensive risk assessment for each individual traveler is essential in order to accurately evaluate traveler-, itinerary-, and destination-specific risks, and to advise on the most appropriate risk management interventions to promote health and prevent adverse health outcomes during travel. Vaccinations might also be required and should be personalized according to the individual traveler’s immunization history, travel itinerary, and the amount of time available before departure. Conclusion A traveler’s health and safety depends on a practitioner’s level of expertise in providing pretravel counseling and vaccinations, if required. Those who advise travelers are encouraged to be aware of the extent of this responsibility and to refer all high-risk travelers to travel medicine professionals whenever possible. PMID:25500599

  4. Travelling wave solutions for some time-delayed equations through factorizations

    International Nuclear Information System (INIS)

    Fahmy, E.S.

    2008-01-01

    In this work, we use factorization method to find explicit particular travelling wave solutions for the following important nonlinear second-order partial differential equations: The generalized time-delayed Burgers-Huxley, time-delayed convective Fishers, and the generalized time-delayed Burgers-Fisher. Using the particular solutions for these equations we find the general solutions, two-parameter solution, as special cases

  5. Inferring changes in water cycle dynamics of intensively managed landscapes via the theory of time-variant travel time distributions

    Science.gov (United States)

    Danesh-Yazdi, Mohammad; Foufoula-Georgiou, Efi; Karwan, Diana L.; Botter, Gianluca

    2016-10-01

    Climatic trends and anthropogenic changes in land cover and land use are impacting the hydrology and water quality of streams at the field, watershed, and regional scales in complex ways. In poorly drained agricultural landscapes, subsurface drainage systems have been successful in increasing crop productivity by removing excess soil moisture. However, their hydroecological consequences are still debated in view of the observed increased concentrations of nitrate, phosphorus, and pesticides in many streams, as well as altered runoff volumes and timing. In this study, we employ the recently developed theory of time-variant travel time distributions within the StorAge Selection function framework to quantify changes in water cycle dynamics resulting from the combined climate and land use changes. Our results from analysis of a subbasin in the Minnesota River Basin indicate a significant decrease in the mean travel time of water in the shallow subsurface layer during the growing season under current conditions compared to the pre-1970s conditions. We also find highly damped year-to-year fluctuations in the mean travel time, which we attribute to the "homogenization" of the hydrologic response due to artificial drainage. The dependence of the mean travel time on the spatial heterogeneity of some soil characteristics as well as on the basin scale is further explored via numerical experiments. Simulations indicate that the mean travel time is independent of scale for spatial scales larger than approximately 200 km2, suggesting that hydrologic data from larger basins may be used to infer the average of smaller-scale-driven changes in water cycle dynamics.

  6. ABSTRACT: CONTAMINANT TRAVEL TIMES FROM THE NEVADA TEST SITE TO YUCCA MOUNTAIN: SENSITIVITY TO POROSITY

    International Nuclear Information System (INIS)

    Karl F. Pohlmann; Jianting Zhu; Jenny B. Chapman; Charles E. Russell; Rosemary W. H. Carroll; David S. Shafer

    2008-01-01

    Yucca Mountain (YM), Nevada, has been proposed by the U.S. Department of Energy as a geologic repository for spent nuclear fuel and high-level radioactive waste. In this study, we investigate the potential for groundwater advective pathways from underground nuclear testing areas on the Nevada Test Site (NTS) to the YM area by estimating the timeframe for advective travel and its uncertainty resulting from porosity value uncertainty for hydrogeologic units (HGUs) in the region. We perform sensitivity analysis to determine the most influential HGUs on advective radionuclide travel times from the NTS to the YM area. Groundwater pathways and advective travel times are obtained using the particle tracking package MODPATH and flow results from the Death Valley Regional Flow System (DVRFS) model by the U.S. Geological Survey. Values and uncertainties of HGU porosities are quantified through evaluation of existing site porosity data and expert professional judgment and are incorporated through Monte Carlo simulations to estimate mean travel times and uncertainties. We base our simulations on two steady state flow scenarios for the purpose of long term prediction and monitoring. The first represents pre-pumping conditions prior to groundwater development in the area in 1912 (the initial stress period of the DVRFS model). The second simulates 1998 pumping (assuming steady state conditions resulting from pumping in the last stress period of the DVRFS model). Considering underground tests in a clustered region around Pahute Mesa on the NTS as initial particle positions, we track these particles forward using MODPATH to identify hydraulically downgradient groundwater discharge zones and to determine which flowpaths will intercept the YM area. Out of the 71 tests in the saturated zone, flowpaths of 23 intercept the YM area under the pre-pumping scenario. For the 1998 pumping scenario, flowpaths from 55 of the 71 tests intercept the YM area. The results illustrate that mean

  7. Using nonparametrics to specify a model to measure the value of travel time

    DEFF Research Database (Denmark)

    Fosgerau, Mogens

    2007-01-01

    Using a range of nonparametric methods, the paper examines the specification of a model to evaluate the willingness-to-pay (WTP) for travel time changes from binomial choice data from a simple time-cost trading experiment. The analysis favours a model with random WTP as the only source of randomn......Using a range of nonparametric methods, the paper examines the specification of a model to evaluate the willingness-to-pay (WTP) for travel time changes from binomial choice data from a simple time-cost trading experiment. The analysis favours a model with random WTP as the only source...... unobserved heterogeneity. This formulation is useful for parametric modelling. The index indicates that the WTP varies systematically with income and other individual characteristics. The WTP varies also with the time difference presented in the experiment which is in contradiction of standard utility theory....

  8. Negotiating on location, timing, duration, and participant in agent-mediated joint activity-travel scheduling

    Science.gov (United States)

    Ma, Huiye; Ronald, Nicole; Arentze, Theo A.; Timmermans, Harry J. P.

    2013-10-01

    Agent-based simulation has become an important modeling approach in activity-travel analysis. Social activities account for a large amount of travel and have an important effect on activity-travel scheduling. Participants in joint activities usually have various options regarding location, participants, and timing and take different approaches to make their decisions. In this context, joint activity participation requires negotiation among agents involved, so that conflicts among the agents can be addressed. Existing mechanisms do not fully provide a solution when utility functions of agents are nonlinear and non-monotonic. Considering activity-travel scheduling in time and space as an application, we propose a novel negotiation approach, which takes into account these properties, such as continuous and discrete issues, and nonlinear and non-monotonic utility functions, by defining a concession strategy and a search mechanism. The results of experiments show that agents having these properties can negotiate efficiently. Furthermore, the negotiation procedure affects individuals’ choices of location, timing, duration, and participants.

  9. Effects of task complexity and time pressure on activity-travel choices : Heteroscedastic logit model and activity-travel simulator experiment

    NARCIS (Netherlands)

    Chen, C.; Chorus, C.G.; Molin, E.J.E.; Van Wee, G.P.

    2015-01-01

    This paper derives, estimates and applies a discrete choice model of activity-travel behaviour that accommodates potential effects of task complexity and time pressure on decision-making. To the best of our knowledge, this is the first time that both factors (task complexity and time pressure) are

  10. Time Savings with Rituximab Subcutaneous Injection versus Rituximab Intravenous Infusion: A Time and Motion Study in Eight Countries

    Science.gov (United States)

    De Cock, Erwin; Kritikou, Persefoni; Sandoval, Mariana; Tao, Sunning; Wiesner, Christof; Carella, Angelo Michele; Ngoh, Charles; Waterboer, Tim

    2016-01-01

    Background Rituximab is a standard treatment for non-Hodgkin lymphoma. The SABRINA trial (NCT01200758) showed that a subcutaneous (SC) rituximab formulation did not compromise efficacy or safety compared with intravenous (IV) infusion. We aimed to quantify active healthcare professional (HCP) time and patient chair time for rituximab SC and IV, including potential time savings. Methods This non-interventional time and motion study was run in eight countries and 30 day oncology units. Rituximab SC data were collected alongside the MabCute trial (NCT01461928); IV data were collected per routine real-world practice. Trained observers recorded active HCP time for pre-specified tasks (stopwatch) and chair time (time of day). A random intercept model was used to analyze active HCP time (by task and for all tasks combined) in the treatment room and drug preparation area, drug administration duration, chair time and patient treatment room time by country and/or across countries. Active HCP and chair time were extrapolated to a patient’s first year of treatment (11 rituximab sessions). Results Mean active HCP time was 35.0 and 23.7 minutes for IV and SC process, respectively (-32%, p time was 27–58%. Absolute reduction in extrapolated active HCP time (first year of treatment) was 1.1–5.2 hours. Mean chair time was 262.1 minutes for IV, including 180.9 minutes infusion duration, vs. 67.3 minutes for SC, including 8.3 minutes SC injection administration (-74%, p time for the first year of treatment was 3.1–5.5 eight-hour days. Conclusions Compared with rituximab IV, rituximab SC was associated with reduced chair time and active HCP time. The latter could be invested in other activities, whereas the former may lead to more available appointments, reducing waiting lists and increasing the efficiency of day oncology units. Trial Registration ClinicalTrials.gov NCT01200758 PMID:27362533

  11. Lost sleep and cyberloafing: Evidence from the laboratory and a daylight saving time quasi-experiment.

    Science.gov (United States)

    Wagner, David T; Barnes, Christopher M; Lim, Vivien K G; Ferris, D Lance

    2012-09-01

    The Internet is a powerful tool that has changed the way people work. However, the ubiquity of the Internet has led to a new workplace threat to productivity-cyberloafing. Building on the ego depletion model of self-regulation, we examine how lost and low-quality sleep influence employee cyberloafing behaviors and how individual differences in conscientiousness moderate these effects. We also demonstrate that the shift to Daylight Saving Time (DST) results in a dramatic increase in cyberloafing behavior at the national level. We first tested the DST-cyberloafing relation through a national quasi-experiment, then directly tested the relation between sleep and cyberloafing in a closely controlled laboratory setting. We discuss the implications of our findings for theory, practice, and future research.

  12. NCBI-compliant genome submissions: tips and tricks to save time and money.

    Science.gov (United States)

    Pirovano, Walter; Boetzer, Marten; Derks, Martijn F L; Smit, Sandra

    2017-03-01

    Genome sequences nowadays play a central role in molecular biology and bioinformatics. These sequences are shared with the scientific community through sequence databases. The sequence repositories of the International Nucleotide Sequence Database Collaboration (INSDC, comprising GenBank, ENA and DDBJ) are the largest in the world. Preparing an annotated sequence in such a way that it will be accepted by the database is challenging because many validation criteria apply. In our opinion, it is an undesirable situation that researchers who want to submit their sequence need either a lot of experience or help from partners to get the job done. To save valuable time and money, we list a number of recommendations for people who want to submit an annotated genome to a sequence database, as well as for tool developers, who could help to ease the process. © The Author 2015. Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  13. Interactive, open source, travel time scenario modelling: tools to facilitate participation in health service access analysis.

    Science.gov (United States)

    Fisher, Rohan; Lassa, Jonatan

    2017-04-18

    Modelling travel time to services has become a common public health tool for planning service provision but the usefulness of these analyses is constrained by the availability of accurate input data and limitations inherent in the assumptions and parameterisation. This is particularly an issue in the developing world where access to basic data is limited and travel is often complex and multi-modal. Improving the accuracy and relevance in this context requires greater accessibility to, and flexibility in, travel time modelling tools to facilitate the incorporation of local knowledge and the rapid exploration of multiple travel scenarios. The aim of this work was to develop simple open source, adaptable, interactive travel time modelling tools to allow greater access to and participation in service access analysis. Described are three interconnected applications designed to reduce some of the barriers to the more wide-spread use of GIS analysis of service access and allow for complex spatial and temporal variations in service availability. These applications are an open source GIS tool-kit and two geo-simulation models. The development of these tools was guided by health service issues from a developing world context but they present a general approach to enabling greater access to and flexibility in health access modelling. The tools demonstrate a method that substantially simplifies the process for conducting travel time assessments and demonstrate a dynamic, interactive approach in an open source GIS format. In addition this paper provides examples from empirical experience where these tools have informed better policy and planning. Travel and health service access is complex and cannot be reduced to a few static modeled outputs. The approaches described in this paper use a unique set of tools to explore this complexity, promote discussion and build understanding with the goal of producing better planning outcomes. The accessible, flexible, interactive and

  14. Modeling Effect of Travel Time Uncertainty and Traffic Information on Use of Park-and-Ride Facilities

    NARCIS (Netherlands)

    Bos, D.M.; Ettema, D.; Molin, E.J.E.

    2004-01-01

    An approach is presented to determine the effect of travel time uncertainty and traffic information on mode choice in general and on the potential patronage of park-and-ride (P&R) facilities in particular. An expected-utility approach is applied to model the effect of travel time uncertainty and

  15. Travel time on arterials and rural highways : state-of-the-practice synthesis on rural data collection technology.

    Science.gov (United States)

    2013-04-01

    "Travel time to a destination is a key piece of information that motorists want and need, and is vital for good decision-making by travelers. Technology now makes it feasible to provide drivers with real-time information about how long it takes to re...

  16. Social Security and Saving: A Time-Series Econometrics Pedagogical Example (With "R" Code)

    Science.gov (United States)

    Wassell, Charles S., Jr.

    2018-01-01

    In 1974, and then again in 1996, Martin Feldstein published studies of the impact of the Social Security system on private saving in the U.S. economy. He found that Social Security depressed personal saving by a substantial amount--up to 50 percent. The author uses the Feldstein data and empirical models in this article to illustrate the steps in…

  17. Efficient Constraint Handling in Electromagnetism-Like Algorithm for Traveling Salesman Problem with Time Windows

    Directory of Open Access Journals (Sweden)

    Alkın Yurtkuran

    2014-01-01

    Full Text Available The traveling salesman problem with time windows (TSPTW is a variant of the traveling salesman problem in which each customer should be visited within a given time window. In this paper, we propose an electromagnetism-like algorithm (EMA that uses a new constraint handling technique to minimize the travel cost in TSPTW problems. The EMA utilizes the attraction-repulsion mechanism between charged particles in a multidimensional space for global optimization. This paper investigates the problem-specific constraint handling capability of the EMA framework using a new variable bounding strategy, in which real-coded particle’s boundary constraints associated with the corresponding time windows of customers, is introduced and combined with the penalty approach to eliminate infeasibilities regarding time window violations. The performance of the proposed algorithm and the effectiveness of the constraint handling technique have been studied extensively, comparing it to that of state-of-the-art metaheuristics using several sets of benchmark problems reported in the literature. The results of the numerical experiments show that the EMA generates feasible and near-optimal results within shorter computational times compared to the test algorithms.

  18. Efficient Constraint Handling in Electromagnetism-Like Algorithm for Traveling Salesman Problem with Time Windows

    Science.gov (United States)

    Yurtkuran, Alkın

    2014-01-01

    The traveling salesman problem with time windows (TSPTW) is a variant of the traveling salesman problem in which each customer should be visited within a given time window. In this paper, we propose an electromagnetism-like algorithm (EMA) that uses a new constraint handling technique to minimize the travel cost in TSPTW problems. The EMA utilizes the attraction-repulsion mechanism between charged particles in a multidimensional space for global optimization. This paper investigates the problem-specific constraint handling capability of the EMA framework using a new variable bounding strategy, in which real-coded particle's boundary constraints associated with the corresponding time windows of customers, is introduced and combined with the penalty approach to eliminate infeasibilities regarding time window violations. The performance of the proposed algorithm and the effectiveness of the constraint handling technique have been studied extensively, comparing it to that of state-of-the-art metaheuristics using several sets of benchmark problems reported in the literature. The results of the numerical experiments show that the EMA generates feasible and near-optimal results within shorter computational times compared to the test algorithms. PMID:24723834

  19. Efficient constraint handling in electromagnetism-like algorithm for traveling salesman problem with time windows.

    Science.gov (United States)

    Yurtkuran, Alkın; Emel, Erdal

    2014-01-01

    The traveling salesman problem with time windows (TSPTW) is a variant of the traveling salesman problem in which each customer should be visited within a given time window. In this paper, we propose an electromagnetism-like algorithm (EMA) that uses a new constraint handling technique to minimize the travel cost in TSPTW problems. The EMA utilizes the attraction-repulsion mechanism between charged particles in a multidimensional space for global optimization. This paper investigates the problem-specific constraint handling capability of the EMA framework using a new variable bounding strategy, in which real-coded particle's boundary constraints associated with the corresponding time windows of customers, is introduced and combined with the penalty approach to eliminate infeasibilities regarding time window violations. The performance of the proposed algorithm and the effectiveness of the constraint handling technique have been studied extensively, comparing it to that of state-of-the-art metaheuristics using several sets of benchmark problems reported in the literature. The results of the numerical experiments show that the EMA generates feasible and near-optimal results within shorter computational times compared to the test algorithms.

  20. Active travel to work in NSW: trends over time and the effect of social advantage.

    Science.gov (United States)

    Zander, Alexis; Rissel, Chris; Rogers, Kris; Bauman, Adrian

    2014-12-01

    Active travel can increase population levels of physical activity, but should be promoted equitably. Socio-economic advantage, housing location and/or car ownership influence walking and cycling (active travel) for transport. We examined active commuting over time in the Sydney Greater Metropolitan Region, and associations between active commuting and socioeconomic advantage, urban/rural location and car ownership at a Local Government Area (LGA) level across New South Wales (NSW). Journey to work data from the 2001, 2006 and 2011 Australian Census were examined. Associations between levels of active commuting in each LGA in NSW and the Socio-Economic Index for Areas (SEIFA), Accessibility/Remoteness Index of Australia (ARIA) and car ownership were examined using negative binomial regression modelling. Between 2001 and 2011, active commuting increased in inner Sydney (relative increase of 24%), decreased slightly in outer Sydney (declined 5.1%) and declined in the Greater Metropolitan Region (down 15%). Overall, active commuting increased slightly (6.8% relative increase). After adjusting for the LGA age and sex profile and all other LGA variables, people living in NSW LGAs with high socioeconomic status, more rural areas and low car ownership were more likely to cycle or walk to work. More needs to be done in NSW to increase levels of active commuting consistently across regions and socio-demographic groups. SO WHAT?: Despite small increases in active travel in the Sydney region, active travel patterns are not evenly distributed across locations or populations.

  1. [Differences between Dutch provinces in perinatal mortality and travel time to hospital].

    Science.gov (United States)

    Ravelli, Anita C J; Rijninks-van Driel, Greta C; Erwich, Jan Jaap H M; Mol, Ben Willem J; Brouwers, Hens A A; Abu Hanna, Ameen; Eskes, Martine

    2011-01-01

    To investigate differences in perinatal mortality between Dutch provinces and to determine the significance of risk factors including travel time from home to the hospital during labour. Cohort study. The study was based on 1,242,725 singleton births in 2000-2006 as recorded in the Netherlands Perinatal Registry. The influence of province on perinatal mortality was estimated, with logistic regression analysis adjusting for risk factors (age, parity, ethnicity, socioeconomic status) and care factors such as start of antenatal care and travel time. The perinatal mortality rate in the Netherlands was 9.9 per 1000 births. The provinces with the highest mortality rates were Friesland (11.3‰), Groningen (11.1‰), Zeeland (10.6‰) and Flevoland (10.4‰). Noord-Brabant (9.2‰) and Limburg (9.2‰) had the lowest mortality rates. These differences were significantly higher for Friesland (odds ratio: 1.16; 95%-CI: 1.05-1.28) and Groningen (odds ratio: 1.13; 95%-CI: 1.02-1.26). Starting late with perinatal care, at 18 weeks of gestation or later was an important risk factor (adjusted odds ratio 1.8; 95%-CI: 1.7-1.8). Low socio-economic status could partly be associated with the higher mortality risk in Groningen. Longer travel time (≥ 20 minutes) was an independent risk factor associated with perinatal mortality. On average 19% of the women travelled ≥ 20 minutes to the hospital. In the provinces Groningen, Friesland, Flevoland and Zeeland these percentages ranged between 32 and 36%. The adjusted odds ratio of travel time was 1.7 (95%-CI 1.6-1.7). The perinatal mortality differs per province. This can be explained by longer travel time to the hospital during labour. Late start of perinatal care and low socio-economic status also affect the mortality rate. These risk factors need to be taken into account during registration, investigation, audit and obstetric policy.

  2. Efficient evaluation of shortest travel-time path queries through spatial mashups

    KAUST Repository

    Zhang, Detian

    2017-01-07

    In the real world, the route/path with the shortest travel time in a road network is more meaningful than that with the shortest network distance for location-based services (LBS). However, not every LBS provider has adequate resources to compute/estimate travel time for routes by themselves. A cost-effective way for LBS providers to estimate travel time for routes is to issue external route requests to Web mapping services (e.g., Google Maps, Bing Maps, and MapQuest Maps). Due to the high cost of processing such external route requests and the usage limits of Web mapping services, we take the advantage of direction sharing, parallel requesting and waypoints supported by Web mapping services to reduce the number of external route requests and the query response time for shortest travel-time route queries in this paper. We first give the definition of sharing ability to reflect the possibility of sharing the direction information of a route with others, and find out the queries that their query routes are independent with each other for parallel processing. Then, we model the problem of selecting the optimal waypoints for an external route request as finding the longest simple path in a weighted complete digraph. As it is a MAX SNP-hard problem, we propose a greedy algorithm with performance guarantee to find the best set of waypoints in an external route request. We evaluate the performance of our approach using a real Web mapping service, a real road network, real and synthetic data sets. Experimental results show the efficiency, scalability, and applicability of our approach.

  3. Time Is Not Space: Core Computations and Domain-Specific Networks for Mental Travels.

    Science.gov (United States)

    Gauthier, Baptiste; van Wassenhove, Virginie

    2016-11-23

    Humans can consciously project themselves in the future and imagine themselves at different places. Do mental time travel and mental space navigation abilities share common cognitive and neural mechanisms? To test this, we recorded fMRI while participants mentally projected themselves in time or in space (e.g., 9 years ago, in Paris) and ordered historical events from their mental perspective. Behavioral patterns were comparable for mental time and space and shaped by self-projection and by the distance of historical events to the mental position of the self, suggesting the existence of egocentric mapping in both dimensions. Nonetheless, self-projection in space engaged the medial and lateral parietal cortices, whereas self-projection in time engaged a widespread parietofrontal network. Moreover, while a large distributed network was found for spatial distances, temporal distances specifically engaged the right inferior parietal cortex and the anterior insula. Across these networks, a robust overlap was only found in a small region of the inferior parietal lobe, adding evidence for its role in domain-general egocentric mapping. Our findings suggest that mental travel in time or space capitalizes on egocentric remapping and on distance computation, which are implemented in distinct dimension-specific cortical networks converging in inferior parietal lobe. As humans, we can consciously imagine ourselves at a different time (mental time travel) or at a different place (mental space navigation). Are such abilities domain-general, or are the temporal and spatial dimensions of our conscious experience separable? Here, we tested the hypothesis that mental time travel and mental space navigation required the egocentric remapping of events, including the estimation of their distances to the self. We report that, although both remapping and distance computation are foundational for the processing of the temporal and spatial dimensions of our conscious experience, their

  4. Adjoint Tomography of Taiwan Region: From Travel-Time Toward Waveform Inversion

    Science.gov (United States)

    Huang, H. H.; Lee, S. J.; Tromp, J.

    2014-12-01

    The complicated tectonic environment such as Taiwan region can modulate the seismic waveform severely and hamper the discrimination and the utilization of later phases. Restricted to the use of only first arrivals of P- and S-wave, the travel-time tomographic models of Taiwan can simulate the seismic waveform barely to a frequency of 0.2 Hz to date. While it has been sufficient for long-period studies, e.g. source inversion, this frequency band is still far from the applications to the community and high-resolution studies. To achieve a higher-frequency simulation, more data and the considerations of off-path and finite-frequency effects are necessary. Based on the spectral-element and the adjoint method recently developed, we prepared 94 MW 3.5-6.0 earthquakes with well-defined location and focal mechanism solutions from Real-Time Moment Tensor Monitoring System (RMT), and preformed an iterative gradient-based inversion employing waveform modeling and finite-frequency measurements of adjoint method. By which the 3-D sensitivity kernels are taken into account realistically and the full waveform information are naturally sought, without a need of any phase pick. A preliminary model m003 using 10-50 sec data was demonstrated and compared with previous travel-time models. The primary difference appears in the mountainous area, where the previous travel-time model may underestimate the S-wave speed in the upper crust, but overestimates in the lower crust.

  5. Stability of Intelligent Transportation Network Dynamics: A Daily Path Flow Adjustment considering Travel Time Differentiation

    Directory of Open Access Journals (Sweden)

    Ming-Chorng Hwang

    2015-01-01

    Full Text Available A theoretic formulation on how traffic time information distributed by ITS operations influences the trajectory of network flows is presented in this paper. The interactions between users and ITS operator are decomposed into three parts: (i travel time induced path flow dynamics (PFDTT; (ii demand induced path flow dynamics (PFDD; and (iii predicted travel time dynamics for an origin-destination (OD pair (PTTDOD. PFDTT describes the collective results of user’s daily route selection by pairwise comparison of path travel time provided by ITS services. The other two components, PTTDOD and PFDD, are concentrated on the evolutions of system variables which are predicted and observed, respectively, by ITS operators to act as a benchmark in guiding the target system towards an expected status faster. In addition to the delivered modelings, the stability theorem of the equilibrium solution in the sense of Lyapunov stability is also provided. A Lyapunov function is developed and employed to the proof of stability theorem to show the asymptotic behavior of the aimed system. The information of network flow dynamics plays a key role in traffic control policy-making. The evaluation of ITS-based strategies will not be reasonable without a well-established modeling of network flow evolutions.

  6. Timetable Design for Minimizing Passenger Travel Time and Congestion for a Single Metro Line

    Directory of Open Access Journals (Sweden)

    Yi Shen

    2018-02-01

    Full Text Available This paper brings a proposal for a timetable optimization model for minimizing the passenger travel time and congestion for a single metro line under time-dependent demand. The model is an integer-programming model that systemically considers the passenger travel time, the capacity of trains, and the capacity of platforms. A multi-objective function and a recursive optimization method are presented to solve the optimization problem. Using the model we can obtain an efficient timetable with minimal passenger travel time and minimal number of congestion events on platforms. Moreover, by increasing the number of dispatches, the critical point from congestion state to free-flow state and the optimal timetable with minimal cost for avoiding congestion on platforms can be obtained. The effectiveness of the model is evaluated by a real example. A half-regular timetable with fixed headways in each operation period and an irregular timetable with unfixed headway are investigated for comparison.

  7. Assessment of systematic measurement errors for acoustic travel-time tomography of the atmosphere.

    Science.gov (United States)

    Vecherin, Sergey N; Ostashev, Vladimir E; Wilson, D Keith

    2013-09-01

    Two algorithms are described for assessing systematic errors in acoustic travel-time tomography of the atmosphere, the goal of which is to reconstruct the temperature and wind velocity fields given the transducers' locations and the measured travel times of sound propagating between each speaker-microphone pair. The first algorithm aims at assessing the errors simultaneously with the mean field reconstruction. The second algorithm uses the results of the first algorithm to identify the ray paths corrupted by the systematic errors and then estimates these errors more accurately. Numerical simulations show that the first algorithm can improve the reconstruction when relatively small systematic errors are present in all paths. The second algorithm significantly improves the reconstruction when systematic errors are present in a few, but not all, ray paths. The developed algorithms were applied to experimental data obtained at the Boulder Atmospheric Observatory.

  8. New heuristics for traveling salesman and vehicle routing problems with time windows

    Energy Technology Data Exchange (ETDEWEB)

    Gendreau, M.; Hertz, A.; Laporte, G.; Mihnea, S.

    1994-12-31

    We consider variants of the Traveling Salesman (TSP) and Vehicle Routing (VRP) Problems in which each customer can only be visited within a pre-specified (hard) time-window. We first present a two-phase (construction and post-optimization) generalized insertion heuristic for the TSPTW. This insertion heuristic is then imbedded in a tabu search metaheuristic in order to solve the VRPTW. Computational results on standard benchmark problems will be reported.

  9. [Travel time and participation in breast cancer screening in a region with high population dispersion].

    Science.gov (United States)

    Borda, Alfredo; Sanz, Belén; Otero, Laura; Blasco, Teresa; García-Gómez, Francisco J; de Andrés, Fuencisla

    2011-01-01

    To analyze the association between travel time and participation in a breast cancer screening program adjusted for contextual variables in the province of Segovia (Spain). We performed an ecological study using the following data sources: the Breast Cancer Early Detection Program of the Primary Care Management of Segovia, the Population and Housing Census for 2001 and the municipal register for 2006-2007. The study period comprised January 2006 to December 2007. Dependent variables consisted of the municipal participation rate and the desired level of municipal participation (greater than or equal to 70%). The key independent variable was travel time from the municipality to the mammography unit. Covariables consisted of the municipalities' demographic and socioeconomic factors. We performed univariate and multivariate Poisson regression analyses of the participation rate, and logistic regression of the desired participation level. The sample was composed of 178 municipalities. The mean participation rate was 75.2%. The desired level of participation (≥ 70%) was achieved in 119 municipalities (67%). In the multivariate Poisson and logistic regression analyses, longer travel time was associated with a lower participation rate and with lower participation after adjustment was made for geographic density, age, socioeconomic status and dependency ratio, with a relative risk index of 0.88 (95% CI: 0.81-0.96) and an odds ratio of 0.22 (95% CI: 0.1-0.47), respectively. Travel time to the mammography unit may help to explain participation in breast cancer screening programs. Copyright © 2010 SESPAS. Published by Elsevier Espana. All rights reserved.

  10. Travel Times, Congestion Levels, and Delays at Intersections Calculated on the Basis of Floating Car Data

    DEFF Research Database (Denmark)

    Lahrmann, Harry; Torp, Kristian

    2010-01-01

    traffic only a few meters away from the measuring spots. The situation is totally the opposite when it comes to log data from GPS receivers in cars. Here detailed information about individual cars in the entire road network is obtained. However, the GPS data is only available from a small subset...... of the cars. This paper presents a method to determine travel time, congestion levels and delays using GPS data from moving vehicles – the so-called floating car data....

  11. Real-time data collection technologies: Enhanced decision-making and cost savings January, 2005

    International Nuclear Information System (INIS)

    Rust, T.L.; Vu, H.Q.

    2006-01-01

    Hand-held computers, Geographic Information Systems (GIS), and wireless communication devices are rapidly replacing traditional methods for field monitoring and data collection. Although pencil and paper remain important means of data transcription, field technicians can now use Personal Digital Assistants (PDA) to record their field notes and monitoring data. As data are uploaded wirelessly from the field, decision-makers can view realtime reports and maps that identify sample locations and monitoring results. The combination of PDAs, wireless communications, and web-based GIS provides field personnel and decision-makers many benefits throughout the life cycle of a project, including improved data consistency, real-time transfer of data from field locations to centralized databases, input validation, elimination of transcription errors, and cost savings. Concerns have been expressed however, about investing in hardware, software, and training for a new technology. This paper, based on several years of experience using wireless technologies for dozens of projects, is focused specifically on two case studies. The first case study is a large lead removal site in the Midwest at which real-time data collection technologies were used throughout the project to collect thousands of data points. The second is the Hurricane Katrina/Rita emergency response requiring rapid data collection under extraordinary circumstances. At both sites, the use of real-time data collection technologies significantly improved the data management process which reduced overall costs and increased efficiency. These results could not have been achieved using traditional data collection procedures. The oral presentation will focus on the advantages and disadvantages of the real-time data collection technologies, lessons learned, and planning considerations. A live demonstration, following a typical data collection scenario in which data are collected and plotted on a GIS map in near real-time

  12. Travel-time source-specific station correction improves location accuracy

    Science.gov (United States)

    Giuntini, Alessandra; Materni, Valerio; Chiappini, Stefano; Carluccio, Roberto; Console, Rodolfo; Chiappini, Massimo

    2013-04-01

    Accurate earthquake locations are crucial for investigating seismogenic processes, as well as for applications like verifying compliance to the Comprehensive Test Ban Treaty (CTBT). Earthquake location accuracy is related to the degree of knowledge about the 3-D structure of seismic wave velocity in the Earth. It is well known that modeling errors of calculated travel times may have the effect of shifting the computed epicenters far from the real locations by a distance even larger than the size of the statistical error ellipses, regardless of the accuracy in picking seismic phase arrivals. The consequences of large mislocations of seismic events in the context of the CTBT verification is particularly critical in order to trigger a possible On Site Inspection (OSI). In fact, the Treaty establishes that an OSI area cannot be larger than 1000 km2, and its larger linear dimension cannot be larger than 50 km. Moreover, depth accuracy is crucial for the application of the depth event screening criterion. In the present study, we develop a method of source-specific travel times corrections based on a set of well located events recorded by dense national seismic networks in seismically active regions. The applications concern seismic sequences recorded in Japan, Iran and Italy. We show that mislocations of the order of 10-20 km affecting the epicenters, as well as larger mislocations in hypocentral depths, calculated from a global seismic network and using the standard IASPEI91 travel times can be effectively removed by applying source-specific station corrections.

  13. Seismic Travel Time Tomography in Modeling Low Velocity Anomalies between the Boreholes

    Science.gov (United States)

    Octova, A.; Sule, R.

    2018-04-01

    Travel time cross-hole seismic tomography is applied to describing the structure of the subsurface. The sources are placed at one borehole and some receivers are placed in the others. First arrival travel time data that received by each receiver is used as the input data in seismic tomography method. This research is devided into three steps. The first step is reconstructing the synthetic model based on field parameters. Field parameters are divided into 24 receivers and 45 receivers. The second step is applying inversion process for the field data that consists of five pairs bore holes. The last step is testing quality of tomogram with resolution test. Data processing using FAST software produces an explicit shape and resemble the initial model reconstruction of synthetic model with 45 receivers. The tomography processing in field data indicates cavities in several place between the bore holes. Cavities are identified on BH2A-BH1, BH4A-BH2A and BH4A-BH5 with elongated and rounded structure. In resolution tests using a checker-board, anomalies still can be identified up to 2 meter x 2 meter size. Travel time cross-hole seismic tomography analysis proves this mothod is very good to describing subsurface structure and boundary layer. Size and anomalies position can be recognized and interpreted easily.

  14. Chinese and Australians showed difference in mental time travel in emotion and content but not specificity

    Directory of Open Access Journals (Sweden)

    Xing-jie eChen

    2015-06-01

    Full Text Available Mental time travel refers to the ability to recall episodic past and imagine future events. The present study aimed to investigate cultural differences in mental time travel between Chinese and Australian university students. A total of 231 students (108 Chinese & 123 Australians participated in the study. Their mental time travel abilities were measured by the Sentence Completion for Events from the Past Test (SCEPT and the Sentence Completion for Events in the Future Test (SCEFT. Results showed that there were no cultural differences in the number of specific events generated for the past or future. Significant differences between the Chinese and Australian participants were found mainly in the emotional valence and content of the events generated. Both Chinese and Australian participants generated more specific positive events compared to negative events when thinking about the future and Chinese participants were more positive about their past than Australian participants when recalled specific events. For content, Chinese participants recalled more events about their interpersonal relationships, while Australian participants imagined more about personal future achievements. These findings shed some lights on cultural differences in episodic past and future thinking.

  15. Deficits in episodic memory and mental time travel in patients with post-traumatic stress disorder.

    Science.gov (United States)

    Zlomuzica, Armin; Woud, Marcella L; Machulska, Alla; Kleimt, Katharina; Dietrich, Lisa; Wolf, Oliver T; Assion, Hans-Joerg; Huston, Joseph P; De Souza Silva, Maria A; Dere, Ekrem; Margraf, Jürgen

    2018-04-20

    Post-traumatic stress disorder (PTSD) is characterized by impairments in mnestic functions, especially in the domain of episodic memory. These alterations might affect different aspects of episodic memory functioning. Here we tested PTSD patients and healthy controls (matched for age, sex and education) in a newly developed virtual reality episodic memory test (VR-EMT), a test for mental time travel, episodic future thinking, and prospective memory (M3xT). In a cross-validation experiment, their performance was further evaluated in the Rivermead Behavioral Memory Test (RBMT). PTSD patients demonstrated impairments in episodic memory formation and mental time travel and showed difficulties in utilizing information from episodic memory to solve problems. Diminished attention and concentration in PTSD did not account for performance deficits in these tasks but higher levels of negative arousal were found in PTSD patients. Furthermore, performance in the VR-EMT and RBMT in PTSD patients correlated negatively with self-reported measures of stress and depression. Our results suggest that deficits in episodic memory formation and mental time travel in PTSD lead to difficulties in utilizing the content of episodic memories for solving problems in the present or to plan future behavior. Clinical implications of these findings and suggestions for cognitive-behavioral treatment of PTSD are discussed. Copyright © 2018 Elsevier Inc. All rights reserved.

  16. Travel time to maternity care and its effect on utilization in rural Ghana: a multilevel analysis.

    Science.gov (United States)

    Masters, Samuel H; Burstein, Roy; Amofah, George; Abaogye, Patrick; Kumar, Santosh; Hanlon, Michael

    2013-09-01

    Rates of neonatal and maternal mortality are high in Ghana. In-facility delivery and other maternal services could reduce this burden, yet utilization rates of key maternal services are relatively low, especially in rural areas. We tested a theoretical implication that travel time negatively affects the use of in-facility delivery and other maternal services. Empirically, we used geospatial techniques to estimate travel times between populations and health facilities. To account for uncertainty in Ghana Demographic and Health Survey cluster locations, we adopted a novel approach of treating the location selection as an imputation problem. We estimated a multilevel random-intercept logistic regression model. For rural households, we found that travel time had a significant effect on the likelihood of in-facility delivery and antenatal care visits, holding constant education, wealth, maternal age, facility capacity, female autonomy, and the season of birth. In contrast, a facility's capacity to provide sophisticated maternity care had no detectable effect on utilization. As the Ghanaian health network expands, our results suggest that increasing the availability of basic obstetric services and improving transport infrastructure may be important interventions. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Soil water storage, mixing dynamics and resulting travel times through the critical zone in northern latitudes

    Science.gov (United States)

    Sprenger, Matthias; Tetzlaff, Doerthe; Weiler, Markus; Soulsby, Chris

    2017-04-01

    Water partitioning in the unsaturated zone into groundwater recharge, plant transpiration, and evaporation is fundamental for estimating storages and travel times. How water is mixed and routed through the soil is of broad interest to understand plant available water, contamination transport and weathering rates in the critical zone. Earlier work has shown how seasonal changes in hydroclimate influence the time variant character of travel times. A strong seasonality characterizes the northern latitudes which are particularly sensitive to climate and land use changes. It is crucial to understand how variation and change in hydroclimate and vegetation phenology impact time variant storage dynamics and flow path partitioning in the unsaturated zone. To better understand the influence of these ecohydrological processes on travel times of evaporative, transpiration and recharge fluxes in northern latitudes, we characterized soil physical properties, hydrometric conditions and soil water isotopic composition in the upper soil profile in two different land scape units in the long term experimental catchment, Bruntland Burn in the Scottish Highlands. Our two sampling locations are characterized by podzol soils with high organic matter content but they differ with regard to their vegetation cover with either Scots Pine (Pinus sylvestris) or heather (Calluna sp. and Erica Sp). To assess storage and mixing dynamics in the vadose zone, we parameterized a numerical 1-D flow model using the soil textural information along with soil moisture and soil water stable isotopes (δ2H and δ18O). The water flow and transport were simulated based on the Richards and the advection dispersion equation. Differences between water flows of mobile and tightly bound soil waters and the mixing between the two pore spaces were considered. Isotopic fractionation due to evaporation from soil and interception storage was taken into account, while plant water uptake did not alter the isotopic

  18. Speedometer app videos to provide real-world velocity-time graph data 1: rail travel

    Science.gov (United States)

    King, Julien

    2018-03-01

    The use of modern rail travel as a source of real-life velocity-time data to aid in the teaching of velocity and acceleration is discussed. A technique for using GPS speedometer apps to produce videos of velocity and time figures during a rail journey is described. The technique is applied to a UK rail journey, demonstrating how students can use its results to produce a velocity-time graph from which acceleration and deceleration figures can be calculated. These are compared with theoretical maximum figures, calculated from the train’s technical specification.

  19. Value of travel-time reliability : commuters' route-choice behavior in the Twin Cities, phase 2.

    Science.gov (United States)

    2012-04-01

    Travel-time variability is a noteworthy factor in network performance. It measures the temporal uncertainty : experienced by users in their movement between any two nodes in a network. The importance : of the time variance depends on the penalties in...

  20. Body wave travel times and amplitudes for present-day seismic model of Mars

    Science.gov (United States)

    Raevskiy, Sergey; Gudkova, Tamara

    At the moment Martian interior structure models are constrained by the satellite observational data (the mass, the moment of inertia factor, the Love number k _{2}) (Konopliv et al., 2011) and high pressure experimental data (Bertka and Fei, 1997). Seismological observations could provide unparalleled capability for studying Martian interiors. Future missions include seismic experiments on Mars (Lognonné et al., 2012). The main instrument for these seismic experiments is a broadband seismometer (Robert et al., 2012). When seismic measurements are not yet available, physically consistent interior models, characterized by properties of relevant minerals, make possible to study of the seismic response of the planet. \\To estimate travel times for direct P, S, core reflected PcP, ScS and core refracted PKP body waves as a function of epicentral distance and hypocentral depth, as well as their amplitudes at the surface for a given marsquake, software product was developed in MatLab, as it encompasses many plotting routines that plot resulting travel times and ray paths. The computational results have been compared with the program TTBox (Knapmeyer, 2004). The code computes seismic ray paths and travel times for a one-dimentional spherical interior model (density and seismic velocities are functions of a radius only). Calculations of travel times tables for direct P, S, core reflected PcP, ScS and core refracted PKP waves and their amplitudes are carried out for a trial seismic model of Mars M14_3 from (Zharkov et al., 2009): the core radius is 1800 km, the thickness of the crust is 50 km. Direct and core reflected P and S waves are recorded to a maximum epicentral distance equal to about 100(°) , and PKP arrivals can be detected for epicental distances larger than 150(°) . The shadow zone is getting wider in comparison with previous results (Knapmeyer, 2010), as the liquid core radius of the seismic model under consideration is larger. Based on the estimates of

  1. 41 CFR 302-3.512 - How many times are we required to pay for an employee's return travel?

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 4 2010-07-01 2010-07-01 false How many times are we required to pay for an employee's return travel? 302-3.512 Section 302-3.512 Public Contracts and Property Management Federal Travel Regulation System RELOCATION ALLOWANCES RELOCATION ALLOWANCES 3-RELOCATION...

  2. Sensitivity studies of unsaturated groundwater flow modeling for groundwater travel time calculations at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Altman, S.J.; Ho, C.K.; Arnold, B.W.; McKenna, S.A.

    1995-01-01

    Unsaturated flow has been modeled through four cross-sections at Yucca Mountain, Nevada, for the purpose of determining groundwater particle travel times from the potential repository to the water table. This work will be combined with the results of flow modeling in the saturated zone for the purpose of evaluating the suitability of the potential repository under the criteria of 10CFR960. One criterion states, in part, that the groundwater travel time (GWTT) from the repository to the accessible environment must exceed 1,000 years along the fastest path of likely and significant radionuclide travel. Sensitivity analyses have been conducted for one geostatistical realization of one cross-section for the purpose of (1) evaluating the importance of hydrological parameters having some uncertainty and (2) examining conceptual models of flow by altering the numerical implementation of the conceptual model (dual permeability (DK) and the equivalent continuum model (ECM). Results of comparisons of the ECM and DK model are also presented in Ho et al

  3. Predicting Flow Breakdown Probability and Duration in Stochastic Network Models: Impact on Travel Time Reliability

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Jing [ORNL; Mahmassani, Hani S. [Northwestern University, Evanston

    2011-01-01

    This paper proposes a methodology to produce random flow breakdown endogenously in a mesoscopic operational model, by capturing breakdown probability and duration. Based on previous research findings that probability of flow breakdown can be represented as a function of flow rate and the duration can be characterized by a hazard model. By generating random flow breakdown at various levels and capturing the traffic characteristics at the onset of the breakdown, the stochastic network simulation model provides a tool for evaluating travel time variability. The proposed model can be used for (1) providing reliability related traveler information; (2) designing ITS (intelligent transportation systems) strategies to improve reliability; and (3) evaluating reliability-related performance measures of the system.

  4. Travel time and attrition from VHA care among women veterans: how far is too far?

    Science.gov (United States)

    Friedman, Sarah A; Frayne, Susan M; Berg, Eric; Hamilton, Alison B; Washington, Donna L; Saechao, Fay; Maisel, Natalya C; Lin, Julia Y; Hoggatt, Katherine J; Phibbs, Ciaran S

    2015-04-01

    Travel time, an access barrier, may contribute to attrition of women veterans from Veterans Health Administration (VHA) care. We examined whether travel time influences attrition: (a) among women veterans overall, (b) among new versus established patients, and (c) among rural versus urban patients. This retrospective cohort study used logistic regression to estimate the association between drive time and attrition, overall and for new/established and rural/urban patients. In total, 266,301 women veteran VHA outpatients in the Fiscal year 2009. An "attriter" did not return for VHA care during the second through third years after her first 2009 visit (T0). Drive time (log minutes) was between the patient's residence and her regular source of VHA care. "New" patients had no VHA visits within 3 years before T0. Models included age, service-connected disability, health status, and utilization as covariates. Overall, longer drive times were associated with higher odds of attrition: drive time adjusted odds ratio=1.11 (99% confidence interval, 1.09-1.14). The relationship between drive time and attrition was stronger among new patients but was not modified by rurality. Attrition among women veterans is sensitive to longer drive time. Linking new patients to VHA services designed to reduce distance barriers (telemedicine, community-based clinics, mobile clinics) may reduce attrition among women new to VHA.

  5. Plant Outage Time Savings Provided by Subcritical Physics Testing at Vogtle Unit 2

    International Nuclear Information System (INIS)

    Cupp, Philip; Heibel, M.D.

    2006-01-01

    The most recent core reload design verification physics testing done at Southern Nuclear Company's (SNC) Vogtle Unit 2, performed prior to initial power operations in operating cycle 12, was successfully completed while the reactor was at least 1% ΔK/K subcritical. The testing program used was the first application of the Subcritical Physics Testing (SPT) program developed by the Westinghouse Electric Company LLC. The SPT program centers on the application of the Westinghouse Subcritical Rod Worth Measurement (SRWM) methodology that was developed in cooperation with the Vogtle Reactor Engineering staff. The SRWM methodology received U. S. Nuclear Regulatory Commission (NRC) approval in August of 2005. The first application of the SPT program occurred at Vogtle Unit 2 in October of 2005. The results of the core design verification measurements obtained during the SPT program demonstrated excellent agreement with prediction, demonstrating that the predicted core characteristics were in excellent agreement with the actual operating characteristics of the core. This paper presents an overview of the SPT Program used at Vogtle Unit 2 during operating cycle 12, and a discussion of the critical path outage time savings the SPT program is capable of providing. (authors)

  6. Self-reported discomfort associated with Daylight Saving Time in Brazilian tropical and subtropical zones.

    Science.gov (United States)

    Alencar, João Carlos Nascimento de; Leocadio-Miguel, Mario André; Duarte, Leandro Lourenção; Louzada, Fernando; Fontenele Araujo, John; Pedrazzoli, Mario

    2017-11-01

    Daylight Saving Time (DST) annually moves clocks 1 hour forward, when daytime is longer than night. Previous studies from medium and high latitude locations have pointed to a disruptive effect of DST on human circadian rhythms. Since Brazil is an equatorial country implementing DST, a different relationship between photic and social synchronisers may interfere with DST effects. To explore the prevalence and duration of self-reported discomfort related to DST among Brazilian residents (latitude 12-33° S, longditude 39-57° W). It was hypothesised that an elevated prevalence of self-reported discomfort would be found in Brazil, due to the pronounced uncoupling between social and geophysical synchronisers. In total, 12 467 volunteers completed a web-based, Brazilian version of Horne-Östberg Morningness-Eveningness Questionnaire, provided demographic information, and answered questions related to DST complaints (discomfort, duration of discomfort). Of the total sample, 45.43% reported no discomfort related to DST, with meaningful proportions for all chronotypes. However, eveningness was most associated with discomfort. About one fourth of the total sample reported discomfort over the whole DST period. Gender interaction is largely supported by these results. DST at low latitude locations may be disruptive for circadian rhythms, since seasonality of sunrise near the equator is negligible or very mild.

  7. Hot times in Whistler : energy saving hybrid systems in area hotels

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2008-01-15

    The resort of Whistler in British Columbia is to host the 2010 Winter Olympics, and the town of Whistler has committed to reducing energy consumption and emissions output in the community's 9500 dwelling units. Commercial hotels and mountain operations in the region are facing higher costs associated with tanked propane supply systems and higher infrastructure costs for some of the proposed alternatives. This article described a hybrid heating system designed by Sempa Power Systems. The systems have now been installed in conference centres and on all large mountain lodge complexes in the region. The hybrid heating system is a patent-pending system that automatically load-balances fossil fuel sources with electricity consumption to reduce energy costs, decrease GHG emissions, and increase efficiencies. Clients at the complexes are monitored online in real time and analyses of empirical data are compared with actual consumption to historical baseline averages. It was concluded that complexes in which the systems have been installed are averaging 28 per cent energy savings, a 39 per cent reduction in greenhouse gases (GHGs), and a 13 per cent reduction in energy consumption. 2 figs.

  8. Promoting Savings at Tax Time through a Video-Based Solution-Focused Brief Coaching Intervention

    Directory of Open Access Journals (Sweden)

    Lance Palmer

    2016-09-01

    Full Text Available Solution-focused brief coaching, based on solution-focused brief therapy, is a well-established practice model and is used widely to help individuals progress toward desired outcomes in a variety of settings. This papers presents the findings of a pilot study that examined the impact of a video-based solution-focused brief coaching intervention delivered in conjunction with income tax preparation services at a Volunteer Income Tax Assistance location (n = 212. Individuals receiving tax preparation assistance were randomly assigned to one of four treatment groups: 1 control group; 2 video-based solution-focused brief coaching; 3 discount card incentive; 4 both the video-based solution-focused brief coaching and the discount card incentive. Results of the study indicate that the video-based solution-focused brief coaching intervention increased both the frequency and amount of self-reported savings at tax time. Results also indicate that financial therapy based interventions may be scalable through the use of technology.

  9. Groundwater travel time uncertainty analysis. Sensitivity of results to model geometry, and correlations and cross correlations among input parameters

    International Nuclear Information System (INIS)

    Clifton, P.M.

    1985-03-01

    This study examines the sensitivity of the travel time distribution predicted by a reference case model to (1) scale of representation of the model parameters, (2) size of the model domain, (3) correlation range of log-transmissivity, and (4) cross correlations between transmissivity and effective thickness. The basis for the reference model is the preliminary stochastic travel time model previously documented by the Basalt Waste Isolation Project. Results of this study show the following. The variability of the predicted travel times can be adequately represented when the ratio between the size of the zones used to represent the model parameters and the log-transmissivity correlation range is less than about one-fifth. The size of the model domain and the types of boundary conditions can have a strong impact on the distribution of travel times. Longer log-transmissivity correlation ranges cause larger variability in the predicted travel times. Positive cross correlation between transmissivity and effective thickness causes a decrease in the travel time variability. These results demonstrate the need for a sound conceptual model prior to conducting a stochastic travel time analysis

  10. Structured printed referral letter (form letter; saves time and improves communication

    Directory of Open Access Journals (Sweden)

    R.P.J.C. Ramanayake

    2013-01-01

    Full Text Available Referral of patients to hospitals, specialists and other institutions is an essential part of primary health care. Patients are referred to specialists when investigation or therapeutic options are exhausted in primary care or when opinion or advice is needed from them. Referral has considerable implications for patients, health care system and health care costs. Good communication between primary and secondary care is essential for the smooth running of any health care system. Referral and reply letters are the sole means of communication between doctors most of the time and breakdown in communication could lead to poor continuity of care, delayed diagnoses, polypharmacy, increased litigation risk and unnecessary testing. A referral letter also helps to avoid patient dissatisfaction and loss of confidence in family physician. Studies of referral letters have reported that specialists are dissatisfied with their quality and content. Inclusion of letter writing skills in the medical curriculum, peer assessment and feedback have shown to improve the quality of referral letters. . Form letters have shown to enhance information content and communication in referral process. In Sri Lanka referral letters are usually hand written and frequent complaints are that these letters do not contain adequate information and retrieval of information is a problem due to poor legibility and clarity. Sometimes Primary care doctors refer patients to hospitals and specialists with only verbal instructions. To address these short comings this form letter was introduced. Based on the guidelines and systematic review of published articles, items of information to be included were decided. Printed forms of the letter are kept in the practice and the doctor has to just fill up relevant information under each heading. The objectives of introducing this structured referral letter was to improve the quality and standard of referral letters and save time for both general

  11. From here to efficiency : time lags between the introduction of new technology and the achievement of fuel savings

    International Nuclear Information System (INIS)

    Mintz, M.; Vyas, A.; Wang, M.; Stodolsky, F.; Cuenca, R.; Gaines, L.

    1999-01-01

    In this paper, the energy savings of new technology offering significant improvements in fuel efficiency are tracked for over 20 years as vehicles incorporating that technology enter the fleet and replace conventional light-duty vehicles. Two separate analyses are discussed: a life-cycle analysis of aluminum-intensive vehicles and a fuel-cycle analysis of the energy and greenhouse gas emissions of double vs. triple fuel-economy vehicles. In both efforts, market-penetration modeling is used to simulate the rate at which new technology enters the new fleet, and stock-adjustment modeling is used to capture the inertia in turnover of new and existing current-technology vehicles. Together, these two effects--slowed market penetration and delayed vehicle replacement--increase the time lag between market introduction and the achievement of substantial energy savings. In both cases, 15-20 years elapse, before savings approach these levels

  12. Inpatient child mortality by travel time to hospital in a rural area of Tanzania.

    Science.gov (United States)

    Manongi, Rachel; Mtei, Frank; Mtove, George; Nadjm, Behzad; Muro, Florida; Alegana, Victor; Noor, Abdisalan M; Todd, Jim; Reyburn, Hugh

    2014-05-01

    To investigate the association, if any, between child mortality and distance to the nearest hospital. The study was based on data from a 1-year study of the cause of illness in febrile paediatric admissions to a district hospital in north-east Tanzania. All villages in the catchment population were geolocated, and travel times were estimated from availability of local transport. Using bands of travel time to hospital, we compared admission rates, inpatient case fatality rates and child mortality rates in the catchment population using inpatient deaths as the numerator. Three thousand hundred and eleven children under the age of 5 years were included of whom 4.6% died; 2307 were admitted from time between admission and death. Assuming uniform mortality in the catchment population, the predicted number of deaths not benefiting from hospital admission prior to death increased by 21.4% per hour of travel time to hospital. If the same admission and death rates that were found at <3 h from the hospital applied to the whole catchment population and if hospital care conferred a 30% survival benefit compared to home care, then 10.3% of childhood deaths due to febrile illness in the catchment population would have been averted. The mortality impact of poor access to hospital care in areas of high paediatric mortality is likely to be substantial although uncertainty over the mortality benefit of inpatient care is the largest constraint in making an accurate estimate. © 2014 The Authors Tropical Medicine & International Health Published by John Wiley & Sons Ltd.

  13. Quality Saving Mechanisms of Mitochondria during Aging in a Fully Time-Dependent Computational Biophysical Model.

    Science.gov (United States)

    Mellem, Daniel; Fischer, Frank; Jaspers, Sören; Wenck, Horst; Rübhausen, Michael

    2016-01-01

    Mitochondria are essential for the energy production of eukaryotic cells. During aging mitochondria run through various processes which change their quality in terms of activity, health and metabolic supply. In recent years, many of these processes such as fission and fusion of mitochondria, mitophagy, mitochondrial biogenesis and energy consumption have been subject of research. Based on numerous experimental insights, it was possible to qualify mitochondrial behaviour in computational simulations. Here, we present a new biophysical model based on the approach of Figge et al. in 2012. We introduce exponential decay and growth laws for each mitochondrial process to derive its time-dependent probability during the aging of cells. All mitochondrial processes of the original model are mathematically and biophysically redefined and additional processes are implemented: Mitochondrial fission and fusion is separated into a metabolic outer-membrane part and a protein-related inner-membrane part, a quality-dependent threshold for mitophagy and mitochondrial biogenesis is introduced and processes for activity-dependent internal oxidative stress as well as mitochondrial repair mechanisms are newly included. Our findings reveal a decrease of mitochondrial quality and a fragmentation of the mitochondrial network during aging. Additionally, the model discloses a quality increasing mechanism due to the interplay of the mitophagy and biogenesis cycle and the fission and fusion cycle of mitochondria. It is revealed that decreased mitochondrial repair can be a quality saving process in aged cells. Furthermore, the model finds strategies to sustain the quality of the mitochondrial network in cells with high production rates of reactive oxygen species due to large energy demands. Hence, the model adds new insights to biophysical mechanisms of mitochondrial aging and provides novel understandings of the interdependency of mitochondrial processes.

  14. Quality Saving Mechanisms of Mitochondria during Aging in a Fully Time-Dependent Computational Biophysical Model.

    Directory of Open Access Journals (Sweden)

    Daniel Mellem

    Full Text Available Mitochondria are essential for the energy production of eukaryotic cells. During aging mitochondria run through various processes which change their quality in terms of activity, health and metabolic supply. In recent years, many of these processes such as fission and fusion of mitochondria, mitophagy, mitochondrial biogenesis and energy consumption have been subject of research. Based on numerous experimental insights, it was possible to qualify mitochondrial behaviour in computational simulations. Here, we present a new biophysical model based on the approach of Figge et al. in 2012. We introduce exponential decay and growth laws for each mitochondrial process to derive its time-dependent probability during the aging of cells. All mitochondrial processes of the original model are mathematically and biophysically redefined and additional processes are implemented: Mitochondrial fission and fusion is separated into a metabolic outer-membrane part and a protein-related inner-membrane part, a quality-dependent threshold for mitophagy and mitochondrial biogenesis is introduced and processes for activity-dependent internal oxidative stress as well as mitochondrial repair mechanisms are newly included. Our findings reveal a decrease of mitochondrial quality and a fragmentation of the mitochondrial network during aging. Additionally, the model discloses a quality increasing mechanism due to the interplay of the mitophagy and biogenesis cycle and the fission and fusion cycle of mitochondria. It is revealed that decreased mitochondrial repair can be a quality saving process in aged cells. Furthermore, the model finds strategies to sustain the quality of the mitochondrial network in cells with high production rates of reactive oxygen species due to large energy demands. Hence, the model adds new insights to biophysical mechanisms of mitochondrial aging and provides novel understandings of the interdependency of mitochondrial processes.

  15. Expression for time travel based on diffusive wave theory: applicability and considerations

    Science.gov (United States)

    Aguilera, J. C.; Escauriaza, C. R.; Passalacqua, P.; Gironas, J. A.

    2017-12-01

    Prediction of hydrological response is of utmost importance when dealing with urban planning, risk assessment, or water resources management issues. With the advent of climate change, special care must be taken with respect to variations in rainfall and runoff due to rising temperature averages. Nowadays, while typical workstations have adequate power to run distributed routing hydrological models, it is still not enough for modeling on-the-fly, a crucial ability in a natural disaster context, where rapid decisions must be made. Semi-distributed time travel models, which compute a watershed's hydrograph without explicitly solving the full shallow water equations, appear as an attractive approach to rainfall-runoff modeling since, like fully distributed models, also superimpose a grid on the watershed, and compute runoff based on cell parameter values. These models are heavily dependent on the travel time expression for an individual cell. Many models make use of expressions based on kinematic wave theory, which is not applicable in cases where watershed storage is important, such as mild slopes. This work presents a new expression for concentration times in overland flow, based on diffusive wave theory, which considers not only the effects of storage but also the effects on upstream contribution. Setting upstream contribution equal to zero gives an expression consistent with previous work on diffusive wave theory; on the other hand, neglecting storage effects (i.e.: diffusion,) is shown to be equivalent to kinematic wave theory, currently used in many spatially distributed time travel models. The newly found expression is shown to be dependent on plane discretization, particularly when dealing with very non-kinematic cases. This is shown to be the result of upstream contribution, which gets larger downstream, versus plane length. This result also provides some light on the limits on applicability of the expression: when a certain kinematic threshold is reached, the

  16. Improvement in access to safe water, household water insecurity, and time savings: A cross-sectional retrospective study in Kenya.

    Science.gov (United States)

    Bisung, Elijah; Elliott, Susan J

    2018-01-03

    This study uses a cross-sectional survey (n = 557) with a retrospective design to examine relationships between improvement in access to safe water supply (i.e. extension of municipal piped water) and a range of social outcomes including water insecurity, household time savings and allocation, and household water expenditure in Usoma, Kenya. Data were collected in July 2016, about 3 years after the intervention, using a modified version of the Household Water Insecurity Access Scale (HWIAS). Having assessed the validity and reliability of the modified HWIAS, we examine how differences in levels of access to safe water influence reported levels of water insecurity as well as amount of money and time savings, post the water intervention. Findings suggest that higher levels of access reduce risk of water insecurity. Households with piped water on premises scored 2.95 points less on the water insecurity scale compared to households with access to unimproved sources. As anticipated, time saved on water collection was re-directed to income generating activities, while money saved was spent primarily on food. Important gender differences were reported, with female headed households having 1.15 points less on the HWIAS than male headed households. This study establishes an innovative approach to evaluating water interventions that can be used in program design and evaluation. The study also emphasises the need for universal access to safe water as envisioned in the Sustainable Development Goals (SDGs). Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Retrieval-travel-time model for free-fall-flow-rack automated storage and retrieval system

    Science.gov (United States)

    Metahri, Dhiyaeddine; Hachemi, Khalid

    2018-03-01

    Automated storage and retrieval systems (AS/RSs) are material handling systems that are frequently used in manufacturing and distribution centers. The modelling of the retrieval-travel time of an AS/RS (expected product delivery time) is practically important, because it allows us to evaluate and improve the system throughput. The free-fall-flow-rack AS/RS has emerged as a new technology for drug distribution. This system is a new variation of flow-rack AS/RS that uses an operator or a single machine for storage operations, and uses a combination between the free-fall movement and a transport conveyor for retrieval operations. The main contribution of this paper is to develop an analytical model of the expected retrieval-travel time for the free-fall flow-rack under a dedicated storage assignment policy. The proposed model, which is based on a continuous approach, is compared for accuracy, via simulation, with discrete model. The obtained results show that the maximum deviation between the continuous model and the simulation is less than 5%, which shows the accuracy of our model to estimate the retrieval time. The analytical model is useful to optimise the dimensions of the rack, assess the system throughput, and evaluate different storage policies.

  18. Travel Time Estimation Using Freeway Point Detector Data Based on Evolving Fuzzy Neural Inference System.

    Directory of Open Access Journals (Sweden)

    Jinjun Tang

    Full Text Available Travel time is an important measurement used to evaluate the extent of congestion within road networks. This paper presents a new method to estimate the travel time based on an evolving fuzzy neural inference system. The input variables in the system are traffic flow data (volume, occupancy, and speed collected from loop detectors located at points both upstream and downstream of a given link, and the output variable is the link travel time. A first order Takagi-Sugeno fuzzy rule set is used to complete the inference. For training the evolving fuzzy neural network (EFNN, two learning processes are proposed: (1 a K-means method is employed to partition input samples into different clusters, and a Gaussian fuzzy membership function is designed for each cluster to measure the membership degree of samples to the cluster centers. As the number of input samples increases, the cluster centers are modified and membership functions are also updated; (2 a weighted recursive least squares estimator is used to optimize the parameters of the linear functions in the Takagi-Sugeno type fuzzy rules. Testing datasets consisting of actual and simulated data are used to test the proposed method. Three common criteria including mean absolute error (MAE, root mean square error (RMSE, and mean absolute relative error (MARE are utilized to evaluate the estimation performance. Estimation results demonstrate the accuracy and effectiveness of the EFNN method through comparison with existing methods including: multiple linear regression (MLR, instantaneous model (IM, linear model (LM, neural network (NN, and cumulative plots (CP.

  19. Travel time tomography with local image regularization by sparsity constrained dictionary learning

    Science.gov (United States)

    Bianco, M.; Gerstoft, P.

    2017-12-01

    We propose a regularization approach for 2D seismic travel time tomography which models small rectangular groups of slowness pixels, within an overall or `global' slowness image, as sparse linear combinations of atoms from a dictionary. The groups of slowness pixels are referred to as patches and a dictionary corresponds to a collection of functions or `atoms' describing the slowness in each patch. These functions could for example be wavelets.The patch regularization is incorporated into the global slowness image. The global image models the broad features, while the local patch images incorporate prior information from the dictionary. Further, high resolution slowness within patches is permitted if the travel times from the global estimates support it. The proposed approach is formulated as an algorithm, which is repeated until convergence is achieved: 1) From travel times, find the global slowness image with a minimum energy constraint on the pixel variance relative to a reference. 2) Find the patch level solutions to fit the global estimate as a sparse linear combination of dictionary atoms.3) Update the reference as the weighted average of the patch level solutions.This approach relies on the redundancy of the patches in the seismic image. Redundancy means that the patches are repetitions of a finite number of patterns, which are described by the dictionary atoms. Redundancy in the earth's structure was demonstrated in previous works in seismics where dictionaries of wavelet functions regularized inversion. We further exploit redundancy of the patches by using dictionary learning algorithms, a form of unsupervised machine learning, to estimate optimal dictionaries from the data in parallel with the inversion. We demonstrate our approach on densely, but irregularly sampled synthetic seismic images.

  20. Time and travel costs incurred by women attending antenatal tests: A costing study.

    Science.gov (United States)

    Verhoef, Talitha I; Daley, Rebecca; Vallejo-Torres, Laura; Chitty, Lyn S; Morris, Stephen

    2016-09-01

    to estimate the costs to women, their friends and family for different antenatal tests in the Down's syndrome (DS) screening pathway. questionnaire-based costing study. eight maternity clinics across the UK. pregnant women (n=574) attending an appointment for DS screening, NIPT or invasive testing between December 2013 and September 2014. using data collected from the questionnaires we calculated the total costs to women by multiplying the time spent at the hospital and travelling to and from it by the opportunity costs of the women and accompanying person and adding travel and childcare costs. Assumptions about the value of opportunity costs were tested in one-way sensitivity analyses. The main outcome measure was the mean cost to the women and friends/family for each test (DS screening, NIPT, and invasive testing). mean costs to women and their family/friend were £33.96 per visit, of which £22.47 were time costs, £9.15 were travel costs and £2.34 were childcare costs. Costs were lowest for NIPT (£22), £32 for DS screening (£44 if combined with NIPT), and highest for invasive testing (£60). Sensitivity analysis revealed that variations around the value of leisure time opportunity costs had the largest influence on the results. there are considerable costs to women, their friends and family when attending different tests in the DS screening pathway. when assessing the cost-effectiveness of changes to this pathway, costs to women should be considered. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. The impact of real-time and predictive traffic information on travelers' behavior on the I-4 corridor. Final report.

    Science.gov (United States)

    2003-07-01

    Real time and predicted traffic information plays a key role in the successful implementation of advanced traveler information systems (ATIS) and advance traffic management systems (ATMS). Traffic information is essentially valuable to both transport...

  2. Analyses of Sea Surface Height, Bottom Pressure and Acoustic Travel Time in the Japan/East Sea

    National Research Council Canada - National Science Library

    Xu, Yongsheng

    2006-01-01

    ...) was deployed in the southwestern JES for two years, from June 1999 to July 2001. The PIESs recorded hourly vertical acoustic travel time and pressure, which are respectively good proxies of baroclinic and barotropic sea level variability...

  3. Groundwater travel time uncertainty analysis: Sensitivity of results to model geometry, and correlations and cross correlations among input parameters

    International Nuclear Information System (INIS)

    Clifton, P.M.

    1984-12-01

    The deep basalt formations beneath the Hanford Site are being investigated for the Department of Energy (DOE) to assess their suitability as a host medium for a high level nuclear waste repository. Predicted performance of the proposed repository is an important part of the investigation. One of the performance measures being used to gauge the suitability of the host medium is pre-waste-emplacement groundwater travel times to the accessible environment. Many deterministic analyses of groundwater travel times have been completed by Rockwell and other independent organizations. Recently, Rockwell has completed a preliminary stochastic analysis of groundwater travel times. This document presents analyses that show the sensitivity of the results from the previous stochastic travel time study to: (1) scale of representation of model parameters, (2) size of the model domain, (3) correlation range of log-transmissivity, and (4) cross-correlation between transmissivity and effective thickness. 40 refs., 29 figs., 6 tabs

  4. Impact of Personal Attitudes on Propensity to Use Autonomous Vehicles for Intercity Travel.

    Science.gov (United States)

    2016-01-01

    The autonomous vehicles are about to become a reality. The researchers estimate the benefits from each autonomous vehicle to be between $2000 and $4500 per vehicles. The : societal benefits include higher travel time savings, reduced congestion, fuel...

  5. PolyWaTT: A polynomial water travel time estimator based on Derivative Dynamic Time Warping and Perceptually Important Points

    Science.gov (United States)

    Claure, Yuri Navarro; Matsubara, Edson Takashi; Padovani, Carlos; Prati, Ronaldo Cristiano

    2018-03-01

    Traditional methods for estimating timing parameters in hydrological science require a rigorous study of the relations of flow resistance, slope, flow regime, watershed size, water velocity, and other local variables. These studies are mostly based on empirical observations, where the timing parameter is estimated using empirically derived formulas. The application of these studies to other locations is not always direct. The locations in which equations are used should have comparable characteristics to the locations from which such equations have been derived. To overcome this barrier, in this work, we developed a data-driven approach to estimate timing parameters such as travel time. Our proposal estimates timing parameters using historical data of the location without the need of adapting or using empirical formulas from other locations. The proposal only uses one variable measured at two different locations on the same river (for instance, two river-level measurements, one upstream and the other downstream on the same river). The recorded data from each location generates two time series. Our method aligns these two time series using derivative dynamic time warping (DDTW) and perceptually important points (PIP). Using data from timing parameters, a polynomial function generalizes the data by inducing a polynomial water travel time estimator, called PolyWaTT. To evaluate the potential of our proposal, we applied PolyWaTT to three different watersheds: a floodplain ecosystem located in the part of Brazil known as Pantanal, the world's largest tropical wetland area; and the Missouri River and the Pearl River, in United States of America. We compared our proposal with empirical formulas and a data-driven state-of-the-art method. The experimental results demonstrate that PolyWaTT showed a lower mean absolute error than all other methods tested in this study, and for longer distances the mean absolute error achieved by PolyWaTT is three times smaller than empirical

  6. Assessment of retinal sensitivity using a time-saving strategy in normal individuals

    Directory of Open Access Journals (Sweden)

    Suzumura H

    2012-11-01

    .Keywords: time-saving strategy, frequency-of-seeing curve, dynamic, Swedish Interactive Threshold Algorithm Standard, Octopus perimeter, Humphrey field analyzer

  7. Remote sensing of temperature and wind using acoustic travel-time measurements

    Energy Technology Data Exchange (ETDEWEB)

    Barth, Manuela; Fischer, Gabi; Raabe, Armin; Weisse, Frank [Leipzig Univ. (Germany). Inst. fuer Meteorologie; Ziemann, Astrid [Technische Univ. Dresden (Germany). Professur fuer Meteorologie

    2013-04-15

    A remote sensing technique to detect area-averaged temperature and flow properties within an area under investigation, utilizing acoustic travel-time measurements, is introduced. This technique uses the dependency of the speed of acoustic signals on the meteorological parameters temperature and wind along the propagation path. The method itself is scalable: It is applicable for investigation areas with an extent of some hundred square metres as well as for small-scale areas in the range of one square metre. Moreover, an arrangement of the acoustic transducers at several height levels makes it possible to determine profiles and gradients of the meteorological quantities. With the help of two examples the potential of this remote sensing technique for simultaneously measuring averaged temperature and flow fields is demonstrated. A comparison of time histories of temperature and wind values derived from acoustic travel-time measurements with point measurements shows a qualitative agreement whereas calculated root-mean-square errors differ for the two example applications. They amount to 1.4 K and 0.3 m/s for transducer distances of 60 m and 0.4 K and 0.2 m/s for transducer distances in the range of one metre. (orig.)

  8. Measuring and crust-correcting finite-frequency travel time residuals - application to southwestern Scandinavia

    Science.gov (United States)

    Kolstrup, M. L.; Maupin, V.

    2015-10-01

    We present a data-processing routine to compute relative finite-frequency travel time residuals using a combination of the Iterative Cross-Correlation and Stack (ICCS) algorithm and the Multi-Channel Cross-Correlation method (MCCC). The routine has been tailored for robust measurement of P- and S-wave travel times in several frequency bands and for avoiding cycle-skipping problems at the shortest periods. We also investigate the adequacy of ray theory to calculate crustal corrections for finite-frequency regional tomography in normal continental settings with non-thinned crust. We find that ray theory is valid for both P and S waves at all relevant frequencies as long as the crust does not contain low-velocity layers associated with sediments at the surface. Reverberations in the sediments perturb the arrival times of the S waves and the long-period P waves significantly, and need to be accounted for in crustal corrections. The data-processing routine and crustal corrections are illustrated using data from a~network in southwestern Scandinavia.

  9. Defining rational hospital catchments for non-urban areas based on travel-time

    Directory of Open Access Journals (Sweden)

    Grzybowski Stefan CW

    2006-10-01

    Full Text Available Abstract Background Cost containment typically involves rationalizing healthcare service delivery through centralization of services to achieve economies of scale. Hospitals are frequently the chosen site of cost containment and rationalization especially in rural areas. Socio-demographic and geographic characteristics make hospital service allocation more difficult in rural and remote regions. This research presents a methodology to model rational catchments or service areas around rural hospitals – based on travel time. Results This research employs a vector-based GIS network analysis to model catchments that better represent access to hospital-based healthcare services in British Columbia's rural and remote areas. The tool permits modelling of alternate scenarios in which access to different baskets of services (e.g. rural maternity care or ICU are assessed. In addition, estimates of the percentage of population that is served – or not served -within specified travel times are calculated. Conclusion The modelling tool described is useful for defining true geographical catchments around rural hospitals as well as modelling the percentage of the population served within certain time guidelines (e.g. one hour for specific health services. It is potentially valuable to policy makers and health services allocation specialists.

  10. Effects of spatial attention on mental time travel in patients with neglect.

    Science.gov (United States)

    Anelli, Filomena; Avanzi, Stefano; Arzy, Shahar; Mancuso, Mauro; Frassinetti, Francesca

    2018-02-02

    Numerous studies agree that time is represented in spatial terms in the brain. Here we investigate how a deficit in orienting attention in space influences the ability to mentally travel in time, that is to recall the past and anticipate the future. Right brain-damaged patients, with (RBD-N+) and without neglect (RBD-N-), and healthy controls (HC) were subjected to a Mental Time Travel (MTT) task. Participants were asked to project themselves in time to past, present or future (i.e., self-projection) and, for each self-projection, to judge whether events were located relatively in the past or the future (i.e., self-reference). The MTT-task was performed before and after a manipulation, through prismatic adaptation (PA), inducing a leftward shift of spatial attention. Before PA, RBD-N+ were slower for future than for past events, whereas RBD-N- and HC responded similarly to past and future events. A leftward shift of spatial attention by PA reduced the difference in past/future processing in RBD-N+ and fastened RBD-N- and HC's response to past events. Assuming that time concepts, such as past/future, are coded with a left-to-right order on a mental time line (MTL), a recursive search of future-events can explain neglect patients' performance. Improvement of the spatial deficit following PA reduces the recursive search of future events on the rightmost part of the MTL, facilitating exploration of past events on the leftmost part of the MTL, finally favoring the correct location of past and future events. In addition, the study of the anatomical correlates of the temporal deficit in mental time travel through voxel-based lesion-symptom mapping showed a correlation with a lesion located in the insula and in the thalamus. These findings provide new insights about the inter-relations of space and time, and can pave the way to a procedure to rehabilitate a deficit in these cognitive domains. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Providing Advanced and Real-Time Travel/Traffic Information to Tourists

    Science.gov (United States)

    1998-10-01

    Advanced traveler information systems (ATIS) analyze and communicate information that can enhance travel efficiency, alleviate congestion, and increase safety. In Texas, tourists (i.e., tripmakers unacquainted with the state) constitute an important ...

  12. Energy Savings Lifetimes and Persistence

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, Ian M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Schiller, Steven R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Todd, Annika [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Billingsley, Megan A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Goldman, Charles A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Schwartz, Lisa C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-02-01

    This technical brief explains the concepts of energy savings lifetimes and savings persistence and discusses how program administrators use these factors to calculate savings for efficiency measures, programs and portfolios. Savings lifetime is the length of time that one or more energy efficiency measures or activities save energy, and savings persistence is the change in savings throughout the functional life of a given efficiency measure or activity. Savings lifetimes are essential for assessing the lifecycle benefits and cost effectiveness of efficiency activities and for forecasting loads in resource planning. The brief also provides estimates of savings lifetimes derived from a national collection of costs and savings for electric efficiency programs and portfolios.

  13. Efficient data analysis and travel time picking methods for crosshole GPR experiments

    DEFF Research Database (Denmark)

    Keskinen, Johanna; Moreau, Julien; Nielsen, Lars

    2013-01-01

    developed a corresponding protocol for performing quality control and first-arrival picking for such data. The crosshole data considered in this study were acquired using 100 MHz borehole antennae from Sensors & Software. Each trans-illumination profile is produced by acquiring successive transmitter gathers...... performed based on visualizing time slices or equal receiver positions with different source positions. The resulting final data cube is then amenable to first-arrival picking and/or to the application of state-of-the-art routines for 3D seismic interpretation, such as similarity check, dip-steering or meta......-attribute analyses. We believe that this approach to 3D representation and analysis of GPR crosshole data greatly improves consistency in travel time picking and reduces the time needed for the picking process. Moreover, the approach is well suited for generation of high quality input data for tomographic inversion...

  14. Catching the tail: Empirical identification of the distribution of the value of travel time

    DEFF Research Database (Denmark)

    Börjesson, Maria; Fosgerau, Mogens; Algers, Staffan

    2012-01-01

    Recent methodological advances in discrete choice analysis in combination with certain stated choice experiments have allowed researchers to check empirically the identification of the distribution of latent variables such as the value of travel time (VTT). Lack of identification is likely...... to be common and the consequences are severe. E.g., the Danish value of time study found the 15% right tail of the VTT distribution to be unidentified, making it impossible to estimate the mean VTT without resorting to strong assumptions with equally strong impact on the resulting estimate. This paper analyses...... data generated from a similar choice experiment undertaken in Sweden during 2007–2008 in which the range of tradeoff values between time and money was significantly increased relative to the Danish experiment. The results show that this change allowed empirical identification of effectively the entire...

  15. HELIOSEISMIC HOLOGRAPHY OF SIMULATED SUNSPOTS: MAGNETIC AND THERMAL CONTRIBUTIONS TO TRAVEL TIMES

    Energy Technology Data Exchange (ETDEWEB)

    Felipe, T. [Departamento de Astrofísica, Universidad de La Laguna, E-38205 La Laguna, Tenerife (Spain); Braun, D. C.; Crouch, A. D. [NorthWest Research Associates, Colorado Research Associates, Boulder, CO 80301 (United States); Birch, A. C., E-mail: tobias@iac.es [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany)

    2016-10-01

    Wave propagation through sunspots involves conversion between waves of acoustic and magnetic character. In addition, the thermal structure of sunspots is very different than that of the quiet Sun. As a consequence, the interpretation of local helioseismic measurements of sunspots has long been a challenge. With the aim of understanding these measurements, we carry out numerical simulations of wave propagation through sunspots. Helioseismic holography measurements made from the resulting simulated wavefields show qualitative agreement with observations of real sunspots. We use additional numerical experiments to determine, separately, the influence of the thermal structure of the sunspot and the direct effect of the sunspot magnetic field. We use the ray approximation to show that the travel-time shifts in the thermal (non-magnetic) sunspot model are primarily produced by changes in the wave path due to the Wilson depression rather than variations in the wave speed. This shows that inversions for the subsurface structure of sunspots must account for local changes in the density. In some ranges of horizontal phase speed and frequency there is agreement (within the noise level in the simulations) between the travel times measured in the full magnetic sunspot model and the thermal model. If this conclusion proves to be robust for a wide range of models, it would suggest a path toward inversions for sunspot structure.

  16. Effect of illegal on-street parking on travel times in urban environment

    Energy Technology Data Exchange (ETDEWEB)

    Morillo Carbonell, C.; Magin Campos Cacheda, J.

    2016-07-01

    The aim of this paper is to evaluate the effect of the on-street illegal parking on the commercial travel time of the vehicles in the area. The effect of the illegal parking in the travel time of the vehicles in the zone is analyzed in an urban scenario in order to quantify the negative impact that illegal parking implies to this, by itself, congested areas. To achieve the objective of the paper, a 3x3 street model has been designed and evaluated for different situations. In this sense, based on a traffic microsimulation model a bunch of scenarios have been considered in function of parameters referred to intensity of vehicles, illegal on street parking level and location of the illegals. Based on the scenarios mentioned, it has been analyzed the effect that the different parameters have on the commercial speed of the vehicles in order to have a first set of information that permits how to act to reduce the effect of illegal on street parking. The results obtained in this article will be able to be used in next steps in order to define direct and indirect reduction strategies referred to illegal on street parking effect. (Author)

  17. Dissolved Organic Carbon 14C in Southern Nevada Groundwater and Implications for Groundwater Travel Times

    Energy Technology Data Exchange (ETDEWEB)

    Hershey, Ronald L. [Nevada University, Reno, NV (United States). Desert Research Institute; Fereday, Wyall [Nevada University, Reno, NV (United States). Desert Research Institute; Thomas, James M [Nevada University, Reno, NV (United States). Desert Research Institute

    2016-08-01

    Dissolved inorganic carbon (DIC) carbon-14 (14C) ages must be corrected for complex chemical and physical reactions and processes that change the amount of 14C in groundwater as it flows from recharge to downgradient areas. Because of these reactions, DIC 14C can produce unrealistically old ages and long groundwater travel times that may, or may not, agree with travel times estimated by other methods. Dissolved organic carbon (DOC) 14C ages are often younger than DIC 14C ages because there are few chemical reactions or physical processes that change the amount of DOC 14C in groundwater. However, there are several issues that create uncertainty in DOC 14C groundwater ages including limited knowledge of the initial (A0) DOC 14C in groundwater recharge and potential changes in DOC composition as water moves through an aquifer. This study examines these issues by quantifying A0 DOC 14C in recharge areas of southern Nevada groundwater flow systems and by evaluating changes in DOC composition as water flows from recharge areas to downgradient areas. The effect of these processes on DOC 14C groundwater ages is evaluated and DOC and DIC 14C ages are then compared along several southern Nevada groundwater flow paths. Twenty-seven groundwater samples were collected from springs and wells in southern Nevada in upgradient, midgradient, and downgradient locations. DOC 14C for upgradient samples ranged from 96 to 120 percent modern carbon (pmc) with an average of 106 pmc, verifying modern DOC 14C ages in recharge areas, which decreases uncertainty in DOC 14C A0 values, groundwater ages, and travel times. The HPLC spectra of groundwater along a flow path in the Spring Mountains show the same general pattern indicating that the DOC compound composition does not change along this flow path

  18. Adaptation through genetic time travel? Fluctuating selection can drive the evolution of bacterial transformation.

    Science.gov (United States)

    Engelstädter, Jan; Moradigaravand, Danesh

    2014-01-22

    Natural transformation is a process whereby bacteria actively take up DNA from the surrounding environment and incorporate it into their genome. Natural transformation is widespread in bacteria, but its evolutionary significance is still debated. Here, we hypothesize that transformation may confer a fitness advantage in changing environments through a process we term 'genetic time travel': by taking up old genes that were retained in the environment, the bacteria may revert to a past genotypic state that proves advantageous in the present or a future environment. We scrutinize our hypothesis by means of a mathematical model involving two bacterial types (transforming and non-transforming), a single locus under natural selection and a free DNA pool. The two bacterial types were competed in environments with changing selection regimes. We demonstrate that for a wide range of parameter values for the DNA turnover rate, the transformation rate and the frequency of environmental change, the transforming type outcompetes the non-transforming type. We discuss the empirical plausibility of our hypothesis, as well as its relationship to other hypotheses for the evolution of transformation in bacteria and sex more generally, speculating that 'genetic time travel' may also be relevant in eukaryotes that undergo horizontal gene transfer.

  19. How accessible are coral reefs to people? A global assessment based on travel time.

    Science.gov (United States)

    Maire, Eva; Cinner, Joshua; Velez, Laure; Huchery, Cindy; Mora, Camilo; Dagata, Stephanie; Vigliola, Laurent; Wantiez, Laurent; Kulbicki, Michel; Mouillot, David

    2016-04-01

    The depletion of natural resources has become a major issue in many parts of the world, with the most accessible resources being most at risk. In the terrestrial realm, resource depletion has classically been related to accessibility through road networks. In contrast, in the marine realm, the impact on living resources is often framed into the Malthusian theory of human density around ecosystems. Here, we develop a new framework to estimate the accessibility of global coral reefs using potential travel time from the nearest human settlement or market. We show that 58% of coral reefs are located travel time from the market is a strong predictor of fish biomass on coral reefs. We also highlight a relative deficit of protection on coral reef areas near people, with disproportional protection on reefs far from people. This suggests that conservation efforts are targeting low-conflict reefs or places that may already be receiving de facto protection due to their isolation. Our global assessment of accessibility in the marine realm is a critical step to better understand the interplay between humans and resources. © 2016 John Wiley & Sons Ltd/CNRS.

  20. Save Energy: Save Money!

    Science.gov (United States)

    Eccli, Eugene; And Others

    This publication is a collection of inexpensive energy saving tips and home improvements for home owners, particularly in low-income areas or in older homes. Section titles are: (1) Keeping Warm; (2) Getting Heat Where You Need It; (3) Using the Sun; (4) Furnaces, Stoves, and Fireplaces; (5) Insulation and Other Energy Needs; (6) Do-It-Yourself…

  1. Prospective and retrospective time perception are related to mental time travel: Evidence from Alzheimer's disease

    NARCIS (Netherlands)

    El Haj, M.; Moroni, C.; Samson, S.; Fasotti, L.; Allain, P.

    2013-01-01

    Unlike prospective time perception paradigms, in which participants are aware that they have to estimate forthcoming time, little is known about retrospective time perception in normal aging and Alzheimer's disease (AD). Our paper addresses this shortcoming by comparing prospective and retrospective

  2. Effects of daylight-saving time changes on stock market returns and stock market volatility: rebuttal.

    Science.gov (United States)

    Kamstra, Mark J; Kramer, Lisa A; Levi, Maurice D

    2013-02-01

    In a 2011 reply to our 2010 comment in this journal, Berument and Dogen maintained their challenge to the existence of the negative daylight-saving effect in stock returns reported by Kamstra, Kramer, and Levi in 2000. Unfortunately, in their reply, Berument and Dogen ignored all of the points raised in the comment, failing even to cite the Kamstra, et al. comment. Berument and Dogen continued to use inappropriate estimation techniques, over-parameterized models, and low-power tests and perhaps most surprisingly even failed to replicate results they themselves reported in their previous paper, written by Berument, Dogen, and Onar in 2010. The findings reported by Berument and Dogen, as well as by Berument, Dogen, and Onar, are neither well-supported nor well-reasoned. We maintain our original objections to their analysis, highlight new serious empirical and theoretical problems, and emphasize that there remains statistically significant evidence of an economically large negative daylight-saving effect in U.S. stock returns. The issues raised in this rebuttal extend beyond the daylight-saving effect itself, touching on methodological points that arise more generally when deciding how to model financial returns data.

  3. Frequency Dependence of Helioseismic Measurements of the Center-to-Limb Effect and Flow-induced Travel-time Shifts

    Science.gov (United States)

    Chen, Ruizhu; Zhao, Junwei

    2018-02-01

    Time–distance helioseismology measures acoustic travel times to infer the structure and flow field of the solar interior; however, both the mean travel times and the travel-time shifts suffer systematic center-to-limb variations, which complicate the interpretation and inversions of the time–distance measurements. In particular, the center-to-limb variation in travel-time shifts (CtoL effect) has a significant impact on the inference of the Sun’s meridional circulation, and needs to be removed from the helioseismic measurements, although the observational properties and the physical cause of the CtoL effect have yet to be investigated. In this study, we measure the CtoL effect in the frequency domain using Doppler-velocity data from the Solar Dynamics Observatory/Helioseismic and Magnetic Imager, and study its properties as a function of disk-centric distance, travel distance, and frequency of acoustic waves. It is found that the CtoL effect has a significant frequency dependence—it reverses sign at a frequency around 5.4 mHz and reaches maximum at around 4.0 mHz before the sign reversal. The tendency of frequency dependence varies with disk-centric distance in a way that both the sign-reversal frequency and the maximum-value frequency decrease closer to the limb. The variation tendency does not change with travel distance, but the variation magnitude is approximately proportional to travel distance. For comparison, the flow-induced travel-time shifts show little frequency dependence. These observational properties provide more clues on the nature of the CtoL effect, and also possibly lead to new ways of effect-removal for a more robust determination of the deep meridional flow.

  4. Travel Time to Clinic but not Neighborhood Crime Rate is Associated with Retention in Care Among HIV-Positive Patients.

    Science.gov (United States)

    Ridgway, Jessica P; Almirol, Ellen A; Schmitt, Jessica; Schuble, Todd; Schneider, John A

    2018-03-29

    Using geospatial analysis, we examined the relationship of distance between a patient's residence and clinic, travel time to clinic, and neighborhood violent crime rates with retention in care or viral suppression among people living with HIV (PLWH). For HIV-positive patients at a large urban clinic, we measured distance and travel time between home and clinic and violent crime rate within a two block radius of the travel route. Kruskal-Wallis rank sum was used to compare outcomes between groups. Over the observation period, 2008-2016, 219/602 (36%) patients were retained in care. Median distance from clinic was 3.6 (IQR 2.1-5.6) miles versus 3.9 (IQR 2.7-6.1) miles among those retained versus not retained in care, p = 0.06. Median travel time by car was 15.9 (IQR 9.6-22.9) versus 17.1 (IQR 12.0-24.6) minutes for those retained versus not retained, p = 0.04. Violent crime rate along travel route was not associated with retention. There was no significant association between travel time or distance and viral suppression.

  5. The methodology for the evaluation of the energy saving by the daylight saving time in Mexico; Metodologia para la evaluacion del ahorro de energia debido al cambio de horario durante la epoca del verano

    Energy Technology Data Exchange (ETDEWEB)

    Ramos Niembro, Gaudencio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    A description is made of the methodology for the evaluation of energy saving by the daylight saving time in Mexico. A mathematical model was developed that would allow the quantitative evaluation of the energy saving by the daylight saving time, through measurements of the consumption of different users from the domestic commercial and industrial sector, considering the various variables that impact the consumption [Espanol] Se describe la metodologia para la evalucion del ahorro de energia por el cambio de horario de verano en Mexico. Se desarrollo un modelo matematico que permitiera evaluar cuantitativamente el ahorro de energia debido al cambio de horario durante la epoca de verano, atraves de mediciones de consumos de los diferentes usuarios de los sectores domestico, comercial e industrial, considerando las diversas variables que impactan en el consumo

  6. 41 CFR 302-4.204 - If my spouse does not accompany me but travels unaccompanied at a different time, what per diem...

    Science.gov (United States)

    2010-07-01

    ... accompany me but travels unaccompanied at a different time, what per diem rate will he/she receive? 302-4.204 Section 302-4.204 Public Contracts and Property Management Federal Travel Regulation System... my spouse does not accompany me but travels unaccompanied at a different time, what per diem rate...

  7. 41 CFR 302-3.219 - Is there a limit on how many times I may receive reimbursement for tour renewal travel?

    Science.gov (United States)

    2010-07-01

    ... many times I may receive reimbursement for tour renewal travel? 302-3.219 Section 302-3.219 Public Contracts and Property Management Federal Travel Regulation System RELOCATION ALLOWANCES RELOCATION....219 Is there a limit on how many times I may receive reimbursement for tour renewal travel? (a) If you...

  8. Experimental Characterization of Seasonal Variations of Infrasonic Travel Times on the Korean Peninsula

    Science.gov (United States)

    Che, I.; Stump, B.

    2009-12-01

    Long-term infrasonic ground-truth events were collected at an active open-pit mine in Korea for 2 years and included more than one thousand blasts. Infrasonic arrivals from these blasts were recorded at two regional arrays, CHNAR in NW direction from the mine and continental path, ULDAR in east direction and open ocean path. The analysis of the ground-truth dataset indicates that travel times of infrasound strongly depend on seasons as well as path environments. Infrasonic waves toward CHNAR propagated as guided waves between the ground and stratosphere with characteristic celerity range of 260-289 m/s and showed seasonal cyclical variations in travel times. Infrasonic waves to ULDAR also propagated as guided waves, but observed celerities indicate that wave ducts were formed at relatively lower heights in the troposphere with correspondingly fast celerity ranging from 322 to 361 m/s, even though propagation distances to both arrays are similar. ULDAR showed more diurnal variation in travel time than seasonal variation. The observations at ULDAR support the existing of an ephemeral ‘SOFAR’ layer in the atmosphere [Herrin et al., 2006] throughout years in open ocean propagation environment. Statistically, CHNAR and ULDAR detected 35.3% and 61.7% of infrasonic signals generated from the entire blasts, respectively. As explained by ray tracing, higher detectability in ocean environment was possible as a result of duct conditions in lower atmosphere. Detectability in summer is higher than spring-winter-autumn seasons in the direction to CHNAR with ULDAR showing the opposite relationship consistent with known seasonal wind variations. To verify the improvement in infrasound location when these seasonal path effects are taken into account, we performed infrasonic locations for selected ground truth events whose infrasonic signals were detected by both arrays. The optimum location was calculated by least-square method using azimuth and arrival time estimates. One set

  9. Rapid Adjustment of Circadian Clocks to Simulated Travel to Time Zones across the Globe.

    Science.gov (United States)

    Harrison, Elizabeth M; Gorman, Michael R

    2015-12-01

    Daily rhythms in mammalian physiology and behavior are generated by a central pacemaker located in the hypothalamic suprachiasmatic nuclei (SCN), the timing of which is set by light from the environment. When the ambient light-dark cycle is shifted, as occurs with travel across time zones, the SCN and its output rhythms must reset or re-entrain their phases to match the new schedule-a sluggish process requiring about 1 day per hour shift. Using a global assay of circadian resetting to 6 equidistant time-zone meridians, we document this characteristically slow and distance-dependent resetting of Syrian hamsters under typical laboratory lighting conditions, which mimic summer day lengths. The circadian pacemaker, however, is additionally entrainable with respect to its waveform (i.e., the shape of the 24-h oscillation) allowing for tracking of seasonally varying day lengths. We here demonstrate an unprecedented, light exposure-based acceleration in phase resetting following 2 manipulations of circadian waveform. Adaptation of circadian waveforms to long winter nights (8 h light, 16 h dark) doubled the shift response in the first 3 days after the shift. Moreover, a bifurcated waveform induced by exposure to a novel 24-h light-dark-light-dark cycle permitted nearly instant resetting to phase shifts from 4 to 12 h in magnitude, representing a 71% reduction in the mismatch between the activity rhythm and the new photocycle. Thus, a marked enhancement of phase shifting can be induced via nonpharmacological, noninvasive manipulation of the circadian pacemaker waveform in a model species for mammalian circadian rhythmicity. Given the evidence of conserved flexibility in the human pacemaker waveform, these findings raise the promise of flexible resetting applicable to circadian disruption in shift workers, frequent time-zone travelers, and any individual forced to adjust to challenging schedules. © 2015 The Author(s).

  10. Accessing doctors at times of need-measuring the distance tolerance of rural residents for health-related travel.

    Science.gov (United States)

    McGrail, Matthew Richard; Humphreys, John Stirling; Ward, Bernadette

    2015-05-29

    Poor access to doctors at times of need remains a significant impediment to achieving good health for many rural residents. The two-step floating catchment area (2SFCA) method has emerged as a key tool for measuring healthcare access in rural areas. However, the choice of catchment size, a key component of the 2SFCA method, is problematic because little is known about the distance tolerance of rural residents for health-related travel. Our study sought new evidence to test the hypothesis that residents of sparsely settled rural areas are prepared to travel further than residents of closely settled rural areas when accessing primary health care at times of need. A questionnaire survey of residents in five small rural communities of Victoria and New South Wales in Australia was used. The two outcome measures were current travel time to visit their usual doctor and maximum time prepared to travel to visit a doctor, both for non-emergency care. Kaplan-Meier charts were used to compare the association between increased distance and decreased travel propensity for closely-settled and sparsely-settled areas, and ordinal multivariate regression models tested significance after controlling for health-related travel moderating factors and town clustering. A total of 1079 questionnaires were completed with 363 from residents in closely-settled locations and 716 from residents in sparsely-settled areas. Residents of sparsely-settled communities travel, on average, 10 min further than residents of closely-settled communities (26.3 vs 16.9 min, p time prepared to travel (54.1 vs 31.9 min, p time remained significant after controlling for demographic and other constraints to access, such as transport availability or difficulties getting doctor appointments, as well as after controlling for town clustering and current travel times. Improved geographical access remains a key issue underpinning health policies designed to improve the provision of rural primary health care

  11. Determination of travel time capsules hydraulic rabbit system channel 2 (JBB 02) at the G.A. Siwabessy reactor

    International Nuclear Information System (INIS)

    Sutrisno; Sunarko; Elisabeth Ratnawati

    2014-01-01

    Rabbit System is an irradiation facilities used for research on neutron activation. There are two types of Rabbit Systems including 4 pieces Rabbit Hydraulic Systems (JBB01 - JBB04) and Rabbit Pneumatic Systems (JBB05). Irradiation facility of hydraulic rabbit system is irradiation facility with media delivery in the form of capsules. Travel time delivery and the return capsule in hydraulic rabbit system facility depends on the magnitude of the observed flow rate on flow measurement instruments for water circulation. To determine the travel time should be observed flow rates varied by opening the valve (JBB02 AA007), so the delivery time and the return capsule in the rabbit facility hydraulic system can be known. Observations made from the results obtained travel time capsule delivery poly ethylene (PE) of the isotope cell to irradiation position appropriate to the graph Y=57,67 e -0,139.x , for capsules Aluminum (Al) appropriate graph Y= 68,178 e -0,189.x , while the travel time of the return capsule poly ethylene (PE) from the irradiation position to the isotope cell appropriate graph Y=56,459 e -13.x , for capsules Al appropriate graph Y= 65,51 e -183.x this result can be used as a reference for determining the travel time desired by the operator. (author)

  12. Travel time analysis for a subsurface drained sub-watershed in Upper Big Walnut Creek Watershed, Ohio

    Science.gov (United States)

    Runoff travel time, which is a function of watershed and storm characteristics, is an important parameter affecting the prediction accuracy of hydrologic models. Although, time of concentration (tc) is a most widely used time parameter, it has multiple conceptual and computational definitions. Most ...

  13. The daylight saving time in Mexico; El cambio de horario durante la epoca del verano en Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Covarrubias Ramos, Rogelio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    The daylight saving time in Mexico for energy saving is analyzed; such a change is made forwarding the clocks one hour in all Mexico the first Sunday of April and backing them an hour the last Sunday of October. Mention is made the reasons why Mexico adopted this measure, the social-economic impact that brings along and the benefits of this daylight saving time. The case of countries that also apply this measure is analyzed. It is expected that this measure attains benefits for the society either collectively or individually through the ecology and the economy. [Espanol] Se analiza el cambio de horario en la epoca de verano en Mexico para ahorrar energia; dicho cambio se realiza al adelantar una hora al reloj en todo el territorio de Mexico el primer domingo de abril y retrazarlo una hora el ultimo domingo de octubre. Se mencionan las razones por las cuales Mexico adopto esta medida, el impacto socio-economico que traera consigo y los beneficios del cambio de horario. Se aborda la situacion de los paises que tambien aplican esta medida. Se espera que esta medida logre beneficios para la sociedad, ya sea en modo colectivo o individual, para la ecologia y para la economia.

  14. A Hard Day’s Knights: Movie Time Travel, the Middle Ages, and a New Millenium

    Directory of Open Access Journals (Sweden)

    John Engle

    2012-10-01

    Full Text Available This article addresses the cinematic treatment of the Middle Ages through an analysis of two recent mass-audience American films, Black Knight and Timeline, both of which feature time travel as a leading plot element. Providing context for this discussion is a brief analysis of other similar films, as well as remarks regarding Twain's Connecticut Yankee, Ruskin's The Stones of Venice, and The Idylls of the King by Tennyson. As in these other works, the films in question use certain popular stereotypes of the Middle Ages—endemic violence, rigid class distinctions, religious fanaticism, spiritual cohesion, etc.—as lens through which to view the contemporary world. In addition to their roles as comic or action entertainment vehicles, Black Knight indirectly addresses American individualism and a cutthroat modern corporate culture, whereas Timeline touches upon millennial anxiety, '90's ethnic cleansing, and the American misadventure in Iraq.

  15. Future-oriented mental time travel in individuals with disordered gambling.

    Science.gov (United States)

    Noël, Xavier; Saeremans, Mélanie; Kornreich, Charles; Jaafari, Nematollah; D'Argembeau, Arnaud

    2017-03-01

    This study investigated the ability of individuals with disordered gambling to imagine future events. Problem gamblers (n=35) and control participants (n=35) were asked to imagine positive and negative future events for three temporal distances (one week, one year, 5-10years). Then, a variety of phenomenological aspects of their future thoughts (e.g., sensory and contextual details, autonoetic consciousness) were rated. Compared to control subjects, problem gamblers generated fewer positive and negative events across all temporal distances, an impairment that was correlated to verbal fluency scores. Furthermore, problem gamblers rated imagined events as containing fewer sensory and contextual details, and lacking autonoetic consciousness. These findings demonstrate that problem gambling is associated with a reduced future-oriented mental time travel ability and, in particular, with diminished autonoetic consciousness when imagining future events. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Travelling wave solutions of (2++1)-dimensional generalised time-fractional Hirota equation

    Science.gov (United States)

    Zhang, Youwei

    2018-03-01

    In this article, we have developed new exact analytical solutions of a nonlinear evolution equation that appear in mathematical physics, a (2+1)-dimensional generalised time-fractional Hirota equation, which describes the wave propagation in an erbium-doped nonlinear fibre with higher-order dispersion. By virtue of the tanh-expansion and complete discrimination system by means of fractional complex transform, travelling wave solutions are derived. Wave interaction for the wave propagation strength and angle of field quantity under the long wave limit are analysed: Bell-shape solitons are found and it is found that the complex transform coefficient in the system affects the direction of the wave propagation, patterns of the soliton interaction, distance and direction.

  17. Doppler and time-travel broadening in ICR plasma isotope separation

    International Nuclear Information System (INIS)

    Karchevskii, A.I.; Potanin, E.P.

    1994-01-01

    Isotopically-selective ion-cyclotron resonance (ICR) heating is one of the most promising plasma isotope separation methods. The separation degree of ICR separation in a plasma depends on the resonance heating selectivity. The selectivity is due to the isotopically-adjacent accelerated ions resonance curve overlapping and therefore, is determined by the width of the resonance curves. In the case of a collisionless plasma in an ideal homogeneous longitudinal magnetic field, the line broadening is mainly determined by Doppler and time-travel effects. These effects differ in nature, and one has some difficulties in distinguishing them when interpreting the resonance curves because both broadenings depend on ion axial velocities. We consider the simplest case: the extrenal heating alternating electric field does not depend on the axial coordinate (the wave number γ = 0). Hence, in this case the Doppler effect does not occur

  18. Preferences for travel time variability – A study of Danish car drivers

    DEFF Research Database (Denmark)

    Hjorth, Katrine; Rich, Jeppe

    preferences, to exclude non-traders, and to avoid complicated issues related to scheduled public transport services. The survey uses customised Internet questionnaires, containing a series of questions related to the traveller’s most recent morning trip to work, e.g.: • Travel time experienced on this day...... (VTT) of 0.34 Euro/minute (approx. 20 Euro/h) which is to be expected given our high-income sample. The VTTV is extremely low, however, at 0.0002 Euro/minute2. The reduced form model yields a similar VTT of 0.32 Euro/minute. The VTTV is very low: 0.006 Euro per minute2, but nonetheless more than 30...

  19. Inverting travel times with a triplication. [spline fitting technique applied to lunar seismic data reduction

    Science.gov (United States)

    Jarosch, H. S.

    1982-01-01

    A method based on the use of constrained spline fits is used to overcome the difficulties arising when body-wave data in the form of T-delta are reduced to the tau-p form in the presence of cusps. In comparison with unconstrained spline fits, the method proposed here tends to produce much smoother models which lie approximately in the middle of the bounds produced by the extremal method. The method is noniterative and, therefore, computationally efficient. The method is applied to the lunar seismic data, where at least one triplication is presumed to occur in the P-wave travel-time curve. It is shown, however, that because of an insufficient number of data points for events close to the antipode of the center of the lunar network, the present analysis is not accurate enough to resolve the problem of a possible lunar core.

  20. Temporal and spatial variations of travel-time residuals in central California for Novaya Zemlya events

    International Nuclear Information System (INIS)

    Robinson, R.; Iyer, H.M.

    1976-01-01

    Eight large nuclear explosions in Novaya Zemlya from October 1969 through November 1974 were used to monitor long-term variations in crustal seismic velocity near the San Andreas fault in central California. Relative P-wave travel-time residuals appear to be accurate to approximately +-0.1 sec. Of the over 100 stations used, none show clearly significant temporal variations in residual greater than this amount, corresponding to about a 4 percent change in velocity in the upper crust. Average relative residuals at individual stations show a large spatial variation of about 1.5 sec. These variations reflect both a complex crustal geology and changes in crustal thickness and provide a potentially powerful tool for studying crustal structure

  1. Solute travel time in the vadose zone under RWMC at INEL

    International Nuclear Information System (INIS)

    Liou, J.C.P.; Tian, J.

    1995-01-01

    Solute transport in the vadose zone under the Radioactive Waste Management Complex (RWMC) at the Idaho National Engineering Laboratory (INEL) is considered. The objective is to assess the relative importance of variables involved in modeling the travel time of a conservative solute from ground surface to water table. The vadose zone under RWMC is composed of several layers of basalt flows interceded with sediment layers. The thickness of the layers varies with location. The hydraulic properties also vary. The extents of the variations are large, with standard deviations exceed mean in some instances. The vadose zone is idealized as composed of horizontal layers. Solute transport starts at the ground surface and moves vertically downwards to the water table. The perceived process is one-dimensional. This study used VS2DT, a computer code developed by the US Geological Survey, for simulating solute transport in variably saturated porous media

  2. Accessibility appraisal of integrated land-use/transport policy strategies: more than just adding up travel time savings

    NARCIS (Netherlands)

    Geurs, Karst Teunis; Zondag, Barry; de Jong, Gerard; de Bok, Michiel

    2010-01-01

    We examine the accessibility benefits associated with some land-use policy strategies for the Netherlands that anticipate on expected climate change. A disaggregate logsum accessibility measure using the Dutch national land-use/transport interaction model TIGRIS XL is used to compute changes in

  3. The diversity of travel behaviour: Motives and social interactions in leisure time activities

    OpenAIRE

    Stauffacher, Michael; Schlich, Robert; Axhausen, Kay W.; Scholz, Roland W.

    2005-01-01

    Influencing travel behaviour towards a more sustainable form has long been the subject of lively discussion. Whilst some claim that urban form can influence mobility patterns, others stress personal characteristics. Still, psychological factors like personal need and motives (e.g., social interaction, recreation, variety seeking and curiosity) are also relevant, especially for the highly individualistic behaviour of leisure travel, but have been largely neglected in travel behaviour studies. ...

  4. Modeling the light-travel-time effect on the far-infrared size of IRC +10216

    Science.gov (United States)

    Wright, Edward L.; Baganoff, Frederick K.

    1995-01-01

    Models of the far-infrared emission from the large circumstellar dust envelope surrounding the carbon star IRC +10216 are used to assess the importance of the light-travel-time effect (LTTE) on the observed size of the source. The central star is a long-period variable with an average period of 644 +/- 17 days and a peak-to-peak amplitude of two magnituds, so a large light-travel-time effect is seen at 1 min radius. An attempt is made to use the LTTE to reconcile the discrepancy between the observations of Fazio et al. and Lester et al. regarding the far-infrared source size. This discrepancy is reviewed in light of recent, high-spatial-resolution observations at 11 microns by Danchi et al. We conclude that IRC +10216 has been resolved on the arcminute scale by Fazio et al. Convolution of the model intensity profile at 61 microns with the 60 sec x 90 sec Gaussian beam of Fazio et al. yields an observed source size full width at half maximum (FWHM) that ranges from approximately 67 sec to 75 sec depending on the phase of the star and the assumed distance to the source. Using a simple r(exp -2) dust distribution and the 106 deg phase of the Fazio et al. observations, the LTTE model reaches a peak size of 74.3 sec at a distance of 300 pc. This agrees favorably with the 78 sec x 6 sec size measured by Fazio et al. Finally, a method is outlined for using the LTTE as a distance indicator to IRC +10216 and other stars with extended mass outflows.

  5. Helioseismic holography of simulated sunspots: dependence of the travel time on magnetic field strength and Wilson depression

    Science.gov (United States)

    Felipe, T.; Braun, D. C.; Birch, A. C.

    2017-08-01

    Improving methods for determining the subsurface structure of sunspots from their seismic signature requires a better understanding of the interaction of waves with magnetic field concentrations. We aim to quantify the impact of changes in the internal structure of sunspots on local helioseismic signals. We have numerically simulated the propagation of a stochastic wave field through sunspot models with different properties, accounting for changes in the Wilson depression between 250 and 550 km and in the photospheric umbral magnetic field between 1500 and 3500 G. The results show that travel-time shifts at frequencies above approximately 3.50 mHz (depending on the phase-speed filter) are insensitive to the magnetic field strength. The travel time of these waves is determined exclusively by the Wilson depression and sound-speed perturbation. The travel time of waves with lower frequencies is affected by the direct effect of the magnetic field, although photospheric field strengths below 1500 G do not leave a significant trace on the travel-time measurements. These results could potentially be used to develop simplified travel-time inversion methods.

  6. Temporal Dissociation of Neocortical and Hippocampal Contributions to Mental Time Travel Using Intracranial Recordings in Humans

    Directory of Open Access Journals (Sweden)

    Roey Schurr

    2018-02-01

    Full Text Available In mental time travel (MTT one is “traveling” back-and-forth in time, remembering, and imagining events. Despite intensive research regarding memory processes in the hippocampus, it was only recently shown that the hippocampus plays an essential role in encoding the temporal order of events remembered, and therefore plays an important role in MTT. Does it also encode the temporal relations of these events to the remembering self? We asked patients undergoing pre-surgical evaluation with depth electrodes penetrating the temporal lobes bilaterally toward the hippocampus to project themselves in time to a past, future, or present time-point, and then make judgments regarding various events. Classification analysis of intracranial evoked potentials revealed clear temporal dissociation in the left hemisphere between lateral-temporal electrodes, activated at ~100–300 ms, and hippocampal electrodes, activated at ~400–600 ms. This dissociation may suggest a division of labor in the temporal lobe during self-projection in time, hinting toward the different roles of the lateral-temporal cortex and the hippocampus in MTT and the temporal organization of the related events with respect to the experiencing self.

  7. Implementation and Comparison of Acoustic Travel-Time Measurement Procedures for the Helioseismic and Magnetic Imager Time-Distance Helioseismology Pipeline

    Science.gov (United States)

    Couvidat, S.; Zhao, J.; Birch, A. C.; Kosovichev, A. G.; Duvall, T. L., Jr.; Parchevsky, K.; Scherrer, P. H.

    2009-01-01

    The Helioseismic and Magnetic Imager (HMI) instrument on board the Solar Dynamics Observatory (SDO) satellite is designed to produce high-resolution Doppler velocity maps of oscillations at the solar surface with high temporal cadence. To take advantage of these high-quality oscillation data, a time-distance helioseismology pipeline has been implemented at the Joint Science Operations Center (JSOC) at Stanford University. The aim of this pipeline is to generate maps of acoustic travel times from oscillations on the solar surface, and to infer subsurface 3D flow velocities and sound-speed perturbations. The wave travel times are measured from cross covariances of the observed solar oscillation signals. For implementation into the pipeline we have investigated three different travel-time definitions developed in time-distance helioseismology: a Gabor wavelet fitting (Kosovichev and Duvall, 1997), a minimization relative to a reference cross-covariance function (Gizon and Birch, 2002), and a linearized version of the minimization method (Gizon and Birch, 2004). Using Doppler velocity data from the Michelson Doppler Imager (MDI) instrument on board SOHO, we tested and compared these definitions for the mean and difference travel-time perturbations measured from reciprocal signals. Although all three procedures return similar travel times in a quiet Sun region, the method of Gizon and Birch (2004) gives travel times that are significantly different from the others in a magnetic (active) region. Thus, for the pipeline implementation we chose the procedures of Kosovichev and Duvall (1997) and Gizon and Birch (2002). We investigated the relationships among these three travel-time definitions, their sensitivities to fitting parameters, and estimated the random errors they produce

  8. Study of a new technique for measuring the travel time of ultrasonic waves using the frequency spectrum

    International Nuclear Information System (INIS)

    Santos, Allan Xavier dos

    2010-01-01

    During the operation of a nuclear plant and other industrial plants, the operational time and the exposition to severe working conditions may cause the wear of its components, consequently, compromising the safety and the performance of the installation. The implementation of periodical inspections helps to ensure the safe operation and the best performance of the plant. In this way, the use of ultrasonic techniques for inspection and materials characterization becomes more and more attractive, since they offer quick, precise results and are technically ease to implement. The usual ultrasonic techniques, need to the measure the travelling time of the ultrasonic wave in the material examined in order to extract information useful to characterize it. Thus, the measurement of the travelling time of the ultrasonic wave is the overriding factor in most of the applications made with ultrasound. In this work a new technique was developed for measuring the travelling time of the ultrasonic wave using a Fourier's Fast Transformer (FFT). It will be shown mathematically and experimentally that it is possible to use the ultrasonic signal in the frequency domain to determine the travelling time of the ultrasonic wave. Five experiments were carried out for the experimental validation of this new technique. The materials used were 20 ceramic pastilles with different porosities and 3 aluminum plates of different thicknesses. The obtained results have shown that the new technique proposed in this work was able to determine the travelling time of the ultrasonic wave with the same precision as the conventional technique. It was shown, furthermore, that this new technique is able to measure the travelling time of the ultrasonic wave in situations where the conventional technique cannot be applied greatly expanding the range of application of ultrasonic testing and inspections. (author)

  9. Prediction of probabilistic sleep distributions following travel across multiple time zones.

    Science.gov (United States)

    Darwent, David; Dawson, Drew; Roach, Greg D

    2010-02-01

    To parameterize and validate a model to estimate average sleep times for long-haul aviation pilots during layovers following travel across multiple time zones. The model equations were based on a weighted distribution of domicile- and local-time sleepers, and included algorithms to account for sleep loss and circadian re-synchronization. Sleep times were collected from participants under normal commercial operating conditions using diaries and wrist activity monitors. Participants included a total of 306 long-haul pilots (113 captains, 120 first officers, and 73 second officers). The model was parameterized based on the average sleep/wake times observed during international flight patterns from Australia to London and Los Angeles (global R2 = 0.72). The parameterized model was validated against the average sleep/wake times observed during flight patterns from Australia to London (r2 = 0.85), Los Angeles (r2 = 0.79), New York (r2 = 0.80), and Johannesburg (r2 = 0.73). Goodness-of-fit was poorer when the parameterized model equations were used to predict the variance across the sleep/wake cycles of individual pilots (R2 = 0.42, 0.35, 0.31, and 0.28 for the validation flight patterns, respectively), in part because of substantial inter-individual variability in sleep timing and duration. It is possible to estimate average sleep times during layovers in international patterns with a reasonable degree of accuracy. Models of this type could form the basis of a stand-alone application to estimate the likelihood that a given duty schedule provides pilots, on average, with an adequate opportunity to sleep.

  10. GEO-SPATIAL MODELING OF TRAVEL TIME TO MEDICAL FACILITIES IN MUNA BARAT DISTRICT, SOUTHEAST SULAWESI PROVINCE, INDONESIA

    Directory of Open Access Journals (Sweden)

    Nelson Sula

    2018-03-01

    Full Text Available Background: Health services are strongly influenced by regional topography. Road infrastructure is a key in access to health services. The geographic information system becomes a tool in modeling access to health services. Objective: To analyze geospatial data of the travel time to medical facilities in Muna Barat district, Southeast Sulawesi Province, Indonesia. Methods: This research used geospatial analysis with classification of raster data then overlaid with raster data such as Digital Elevation Modeling (DEM, Road of Vector data, and the point of Public Health Center (Puskesmas. Results: The result of geospatial analysis showed that the travel time to Puskesmas in Napano Kusambi and Kusambi sub districts is between 90-120 minutes, and travel time to the hospital in Kusambi sub district is required more than 2 hours. Conclusion: The output of this geospatial analysis can be an input for local government in planning infrastructure development in Muna Barat District, Indonesia.

  11. Time-saving design of experiment protocol for optimization of LC-MS data processing in metabolomic approaches.

    Science.gov (United States)

    Zheng, Hong; Clausen, Morten Rahr; Dalsgaard, Trine Kastrup; Mortensen, Grith; Bertram, Hanne Christine

    2013-08-06

    We describe a time-saving protocol for the processing of LC-MS-based metabolomics data by optimizing parameter settings in XCMS and threshold settings for removing noisy and low-intensity peaks using design of experiment (DoE) approaches including Plackett-Burman design (PBD) for screening and central composite design (CCD) for optimization. A reliability index, which is based on evaluation of the linear response to a dilution series, was used as a parameter for the assessment of data quality. After identifying the significant parameters in the XCMS software by PBD, CCD was applied to determine their values by maximizing the reliability and group indexes. Optimal settings by DoE resulted in improvements of 19.4% and 54.7% in the reliability index for a standard mixture and human urine, respectively, as compared with the default setting, and a total of 38 h was required to complete the optimization. Moreover, threshold settings were optimized by using CCD for further improvement. The approach combining optimal parameter setting and the threshold method improved the reliability index about 9.5 times for a standards mixture and 14.5 times for human urine data, which required a total of 41 h. Validation results also showed improvements in the reliability index of about 5-7 times even for urine samples from different subjects. It is concluded that the proposed methodology can be used as a time-saving approach for improving the processing of LC-MS-based metabolomics data.

  12. SENSITIVITY OF HELIOSEISMIC TRAVEL TIMES TO THE IMPOSITION OF A LORENTZ FORCE LIMITER IN COMPUTATIONAL HELIOSEISMOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    Moradi, Hamed; Cally, Paul S., E-mail: hamed.moradi@monash.edu [Monash Centre for Astrophysics, School of Mathematical Sciences, Monash University, Clayton, Victoria 3800 (Australia)

    2014-02-20

    The rapid exponential increase in the Alfvén wave speed with height above the solar surface presents a serious challenge to physical modeling of the effects of magnetic fields on solar oscillations, as it introduces a significant Courant-Friedrichs-Lewy time-step constraint for explicit numerical codes. A common approach adopted in computational helioseismology, where long simulations in excess of 10 hr (hundreds of wave periods) are often required, is to cap the Alfvén wave speed by artificially modifying the momentum equation when the ratio between the Lorentz and hydrodynamic forces becomes too large. However, recent studies have demonstrated that the Alfvén wave speed plays a critical role in the MHD mode conversion process, particularly in determining the reflection height of the upwardly propagating helioseismic fast wave. Using numerical simulations of helioseismic wave propagation in constant inclined (relative to the vertical) magnetic fields we demonstrate that the imposition of such artificial limiters significantly affects time-distance travel times unless the Alfvén wave-speed cap is chosen comfortably in excess of the horizontal phase speeds under investigation.

  13. Travel Times, Streamflow Velocities, and Dispersion Rates in the Yellowstone River, Montana

    Science.gov (United States)

    McCarthy, Peter M.

    2009-01-01

    The Yellowstone River is a vital natural resource to the residents of southeastern Montana and is a primary source of water for irrigation and recreation and the primary source of municipal water for several cities. The Yellowstone River valley is the primary east-west transportation corridor through southern Montana. This complex of infrastructure makes the Yellowstone River especially vulnerable to accidental spills from various sources such as tanker cars and trucks. In 2008, the U.S. Geological Survey (USGS), in cooperation with the Montana Department of Environmental Quality, initiated a dye-tracer study to determine instream travel times, streamflow velocities, and dispersion rates for the Yellowstone River from Lockwood to Glendive, Montana. The purpose of this report is to describe the results of this study and summarize data collected at each of the measurement sites between Lockwood and Glendive. This report also compares the results of this study to estimated travel times from a transport model developed by the USGS for a previous study. For this study, Rhodamine WT dye was injected at four locations in late September and early October 2008 during reasonably steady streamflow conditions. Streamflows ranged from 3,490 to 3,770 cubic feet per second upstream from the confluence of the Bighorn River and ranged from 6,520 to 7,570 cubic feet per second downstream from the confluence of the Bighorn River. Mean velocities were calculated for each subreach between measurement sites for the leading edge, peak concentration, centroid, and trailing edge at 10 percent of the peak concentration. Calculated velocities for the centroid of the dye plume for subreaches that were completely laterally mixed ranged from 1.83 to 3.18 ft/s within the study reach from Lockwood Bridge to Glendive Bridge. The mean of the completely mixed centroid velocity for the entire study reach, excluding the subreach between Forsyth Bridge and Cartersville Dam, was 2.80 ft/s. Longitudinal

  14. A Population-Based Analysis of Time to Surgery and Travel Distances for Brachial Plexus Surgery.

    Science.gov (United States)

    Dy, Christopher J; Baty, Jack; Saeed, Mohammed J; Olsen, Margaret A; Osei, Daniel A

    2016-09-01

    Despite the importance of timely evaluation for patients with brachial plexus injuries (BPIs), in clinical practice we have noted delays in referral. Because the published BPI experience is largely from individual centers, we used a population-based approach to evaluate the delivery of care for patients with BPI. We used statewide administrative databases from Florida (2007-2013), New York (2008-2012), and North Carolina (2009-2010) to create a cohort of patients who underwent surgery for BPI (exploration, repair, neurolysis, grafting, or nerve transfer). Emergency department and inpatient records were used to determine the time interval between the injury and surgical treatment. Distances between treating hospitals and between the patient's home ZIP code and the surgical hospital were recorded. A multivariable logistic regression model was used to determine predictors for time from injury to surgery exceeding 365 days. Within the 222 patients in our cohort, median time from injury to surgery was 7.6 months and exceeded 365 days in 29% (64 of 222 patients) of cases. Treatment at a smaller hospital for the initial injury was significantly associated with surgery beyond 365 days after injury. Patient insurance type, travel distance for surgery, distance between the 2 treating hospitals, and changing hospitals between injury and surgery did not significantly influence time to surgery. Nearly one third of patients in Florida, New York, and North Carolina underwent BPI surgery more than 1 year after the injury. Patients initially treated at smaller hospitals are at risk for undergoing delayed BPI surgery. These findings can inform administrative and policy efforts to expedite timely referral of patients with BPI to experienced centers. Copyright © 2016 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  15. Travelers' Health: Pregnant Travelers

    Science.gov (United States)

    ... las picaduras de insectos Business Travel Cold Climates Counterfeit Medicines Cruise Ship Travel Families with Children Fish ... and motion sickness and appear to have a good safety record. VACCINES In the best possible scenario, ...

  16. Time-saving method of orbital thermal regime calculations of nanosatellites as exemplified by a 3U CubeSat

    Directory of Open Access Journals (Sweden)

    Gorev Vasily

    2018-01-01

    Full Text Available A time-saving approach to perform technical calculations of thermal conditions of orbital motion of 3U CubeSat nanosatellite was applied, which made it possible to make the thermal calculations of a satellite with simple structure geometry using MatLab and SolidWorks Simulation. Passive thermal regulation facilities are sufficient for a 3U CubeSat to provide thermal conductivity of the case’s structural elements and to remove heat from the lighted surface and internal components to the satellite’s shadowed surface. Application of spectrally selective coatings allows narrowing the range of surface temperatures of 3U CubeSat.

  17. Multi-Track Year-Round Schooling as Cost Saving Reform: Not Just a Matter of Time

    OpenAIRE

    Jennifer Graves; Steven McMullen; Kathryn Rouse

    2013-01-01

    In the face of school crowding and fears about inequality-inducing summer learning loss, many schools have started to adopt multi-track year-round school calendars, which keep the same number of school days, but spread them more evenly across the calendar year. This change allows schools to support a larger student population by rotating which students are on break at any point in time. While year-round schooling can save money, the impact on academic achievement is uncertain and only recentl...

  18. Crustal contributions in teleseismic P-wave travel times and their effect on Tomographic models below India and Tibet

    Science.gov (United States)

    Mohanty, D. D.

    2015-12-01

    The variations in crustal thickness and topography may affect the travel time anomalies and hence attribute significant contributions in the travel time delays into mantle. The delayed arrivals in Tibet and Himalaya are expected due to the thick crust and low average crustal velocities whereas the arrivals are early in the regions of Indian shield compared to IASP 91 and need significant crustal correction term to decipher an exact tomographic model of the whole region. As the near vertical arrivals of teleseismic P waves (distance range 30-900) make it difficult to resolve crustal scale features for their inability to cross at crustal depths, station terms along with crustal corrections can be used to incorporate the effects of unresolved features of crust and upper mantle and to avoid the mapping of crustal travel time anomalies into the mantle. Keeping in view that these corrections using 3D models are as good as their resolution, we prefer CRUST1.0 over CRUST 2.0 to modify IASP91 for the crustal part and the modified velocity model has been used to obtain the travel time delays which may happen due to changes in velocity and thickness. The corrections are obtained for each event-station pair (ray or ray path) used in tomography and the times are subtracted from the input delay time vectors prior to inversion to prepare a modified tomographic model.

  19. "I can see clearly now": the effect of cue imageability on mental time travel.

    Science.gov (United States)

    Rasmussen, Katrine W; Berntsen, Dorthe

    2014-10-01

    Mental time travel (MTT) is the ability to mentally project oneself backward or forward in time, in order to remember an event from one's personal past or to imagine a possible event in one's personal future. Recent work has suggested that, although past and future MTT may rely on shared neurocognitive substrates, the two temporal directions may interact differently with components of this underlying system. Here, we asked 151 participants to recall or imagine past and future autobiographical events in response to high- and low-imageable cue words. The results showed that high- and low-imageable cued events differed markedly on almost all measures, suggesting that imagery acts as a facilitator when constructing both past and possible future events. In line with previous work, future events less often referred to specific events, contained fewer details, and were more positive and idyllic than past events. However, these main effects were qualified by a number of interactions. In particular, we found an increased effect of cue imageability for past as compared to future events, suggesting that the generation of past events is more sensitive to the ability of the cues to invoke the sensory components of the encoding context, whereas the construction of future events is more driven by context-independent schemata.

  20. Measuring Values Of Environmental Quality Improvement And Leisure Time Through Combining Contingent Valuation and Travel Cost Data

    OpenAIRE

    Young Sook Eom; Douglas M. Larson

    2004-01-01

    This paper demonstrates a utility-theoretic empirical framework for estimating values of environmental quality improvement by combining travel cost and contingent valuation data in a two-constraint (time and money) budget framework. Recgninzing the role of time "prices" and time budget, the recreation demand and willingness to pay (WTP) functiuons are specified with full price and full budget arguments, with the opportunity cost of time being a fraction of wage rate. When applied to the case ...

  1. REM-3D Reference Datasets: Reconciling large and diverse compilations of travel-time observations

    Science.gov (United States)

    Moulik, P.; Lekic, V.; Romanowicz, B. A.

    2017-12-01

    A three-dimensional Reference Earth model (REM-3D) should ideally represent the consensus view of long-wavelength heterogeneity in the Earth's mantle through the joint modeling of large and diverse seismological datasets. This requires reconciliation of datasets obtained using various methodologies and identification of consistent features. The goal of REM-3D datasets is to provide a quality-controlled and comprehensive set of seismic observations that would not only enable construction of REM-3D, but also allow identification of outliers and assist in more detailed studies of heterogeneity. The community response to data solicitation has been enthusiastic with several groups across the world contributing recent measurements of normal modes, (fundamental mode and overtone) surface waves, and body waves. We present results from ongoing work with body and surface wave datasets analyzed in consultation with a Reference Dataset Working Group. We have formulated procedures for reconciling travel-time datasets that include: (1) quality control for salvaging missing metadata; (2) identification of and reasons for discrepant measurements; (3) homogenization of coverage through the construction of summary rays; and (4) inversions of structure at various wavelengths to evaluate inter-dataset consistency. In consultation with the Reference Dataset Working Group, we retrieved the station and earthquake metadata in several legacy compilations and codified several guidelines that would facilitate easy storage and reproducibility. We find strong agreement between the dispersion measurements of fundamental-mode Rayleigh waves, particularly when made using supervised techniques. The agreement deteriorates substantially in surface-wave overtones, for which discrepancies vary with frequency and overtone number. A half-cycle band of discrepancies is attributed to reversed instrument polarities at a limited number of stations, which are not reflected in the instrument response history

  2. Travelers' Health

    Science.gov (United States)

    ... Stamaril clinics Disease Directory Resources Resources for Travelers Adventure Travel Animal Safety Blood Clots Bug Bites Evite ... Minute Travel Long-Term Travel Mass Gatherings Medical Tourism Mental Health Motion Sickness Natural Disasters Pregnant Travelers ...

  3. Implementation and Comparison of Acoustic Travel-Time Measurement Procedures for the Solar Dynamics Observatory-Helioseismic and Magnetic Imager Time-Distance Helioseismology Pipeline

    Science.gov (United States)

    Couvidat, S.; Zhao, J.; Birch, A. C.; Kosovichev, A. G.; Duvall, Thomas L., Jr.; Parchevsky, K.; Scherrer, P. H.

    2010-01-01

    The Helioseismic and Magnetic Imager (HMI) instrument onboard the Solar Dynamics Observatory (SDO) satellite is designed to produce high-resolution Doppler-velocity maps of oscillations at the solar surface with high temporal cadence. To take advantage of these high-quality oscillation data, a time - distance helioseismology pipeline (Zhao et al., Solar Phys. submitted, 2010) has been implemented at the Joint Science Operations Center (JSOC) at Stanford University. The aim of this pipeline is to generate maps of acoustic travel times from oscillations on the solar surface, and to infer subsurface 3D flow velocities and sound-speed perturbations. The wave travel times are measured from cross-covariances of the observed solar oscillation signals. For implementation into the pipeline we have investigated three different travel-time definitions developed in time - distance helioseismology: a Gabor-wavelet fitting (Kosovichev and Duvall, SCORE'96: Solar Convection and Oscillations and Their Relationship, ASSL, Dordrecht, 241, 1997), a minimization relative to a reference cross-covariance function (Gizon and Birch, Astrophys. J. 571, 966, 2002), and a linearized version of the minimization method (Gizon and Birch, Astrophys. J. 614, 472, 2004). Using Doppler-velocity data from the Michelson Doppler Imager (MDI) instrument onboard SOHO, we tested and compared these definitions for the mean and difference traveltime perturbations measured from reciprocal signals. Although all three procedures return similar travel times in a quiet-Sun region, the method of Gizon and Birch (Astrophys. J. 614, 472, 2004) gives travel times that are significantly different from the others in a magnetic (active) region. Thus, for the pipeline implementation we chose the procedures of Kosovichev and Duvall (SCORE'96: Solar Convection and Oscillations and Their Relationship, ASSL, Dordrecht, 241, 1997) and Gizon and Birch (Astrophys. J. 571, 966, 2002). We investigated the relationships among

  4. Tomography of crustal P and S travel times across the western United States

    Science.gov (United States)

    Steck, Lee K.; Begnaud, Michael L.; Phillips, Scott; Stead, Richard

    2011-11-01

    Data from the USArray combined with local, regional, and national networks provide an unprecedented opportunity for imaging the crust of the western United States. We employ a simple tomography scheme to invert Pg and Sg travel times for velocity structure. The approach is analogous to Pn tomography: we assume a great circle arc between source and receiver and solve for station and event terms along with 2-D velocity structure. Pg velocities are high in the Snake River Plain, western Washington and the Columbia Plateau, and in central California. The Colorado Plateau falls midrange while the Basin and Range is slow, as are the Geysers region north of the San Francisco Bay and the Salton Trough. For Sg, the Snake River plain is fast, as is the entire Cordillera from the Southern Sierra Nevada up through the Cascades. Both the Colorado Plateau and most of the Rocky Mountains are also fast. At the highest point of the Rocky Mountains, the Aspen Anomaly is a low-velocity region. The Basin and Range is a composite of slower to the west abutting the Sierra Nevada and faster in eastern Nevada. Coastal California is slow, with the exception of the San Francisco Bay region and far northern California. The continental crust of the North American craton appears slightly fast for both Pg and Sg. Our observations and their trends compare well with middle to upper crustal velocity estimates from previous studies. They also compare reasonably well with average crustal velocities from the same studies.

  5. Life review therapy enhances mental time travel in patients with schizophrenia.

    Science.gov (United States)

    Chen, Gui-Fang; Liu, Lu-Lu; Cui, Ji-Fang; Chen, Tao; Qin, Xiao-Jing; Gan, Jie-Chun; Bi, Bin; Neumann, David L; Shum, David H K; Wang, Ya; Chan, Raymond C K

    2017-12-01

    Mental Time Travel (MTT) is the ability of individuals to project themselves to the past or to the future. Studies have shown that schizophrenia (SZ) patients are impaired in MTT. The present study aimed to examine whether MTT in patients with SZ can be improved through Life Review Therapy. Fifty patients with SZ were randomly assigned to the training (SZ-training) or control (SZ-control) group. Whereas the SZ-training group received four-week Life Review Therapy in addition to conventional treatment, the SZ-control group only received conventional treatment. MTT, emotional status, life satisfaction and cognitive functions were assessed before and after the training. We also recruited 25 matched healthy controls to complete all the assessments at baseline. After training, the SZ-training group showed higher specificity and more field perspective than the SZ-control group. No significant difference was found between the SZ-training group post-training assessment and the healthy controls. The SZ-training group also showed significant improvements in emotional expression, semantic memory and verbal fluency, but the SZ-control group did not show such improvements. These results indicated that Life Review Therapy is effective in improving MTT of SZ patients. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Mental Time Travel into the Past and the Future in Healthy Aged Adults: An fMRI Study

    Science.gov (United States)

    Viard, Armelle; Chetelat, Gael; Lebreton, Karine; Desgranges, Beatrice; Landeau, Brigitte; de La Sayette, Vincent; Eustache, Francis; Piolino, Pascale

    2011-01-01

    Remembering the past and envisioning the future rely on episodic memory which enables mental time travel. Studies in young adults indicate that past and future thinking share common cognitive and neural underpinnings. No imaging data is yet available in healthy aged subjects. Using fMRI, we scanned older subjects while they remembered personal…

  7. Simple time-saving method for iron determination based on fluorescence quenching of an azaflavanon-3-ol compound.

    Science.gov (United States)

    Başoğlu, Aysel; Tosun, Gonca; Ocak, Miraç; Alp, Hakan; Yaylı, Nurettin; Ocak, Ümmühan

    2015-03-18

    A simple and time-saving spectrofluorometric method developed using an azaflavanon-3-ol compound was used for the determination of iron in various food samples. Nitric acid and hydrogen peroxide were used for digestion of samples in a closed microwave system. The method was validated by analyzing two certified reference materials (CRM-SA-C Sandy Soil C and Mixed Polish Herbs INCT-MPH-2). Measurements were carried out using a modified standard addition method. The standard addition graph was linear until 21.6 mg/L in the determination of iron(III). Detection and quantification limits were 0.81 and 2.4 mg/L, respectively. Satisfactory accuracy was obtained for spinach, dill, mint, purslane, rocket, red lentils, dry beans, and two iron medicinal tablets. High recoveries were found for streamwater samples fortified at three different concentrations. The method is simple, time-saving, cost-effective, and suitable for the determination of the iron content of foods.

  8. Teleseismic Travel-Time Tomography of the Sierra Nevada and its Foundering Lithosphere

    Science.gov (United States)

    Reeg, H.; Jones, C. H.; Gilbert, H.; Owens, T.; Zandt, G.

    2007-12-01

    Inferences of foundering lithosphere under the southern Sierra have mostly been based upon xenolith petrology and seismic tomography. To better evaluate the extent and geometry of any such unstable lithosphere, we timed teleseismic bodywave arrivals from approximately 500 teleseisms at 75 stations occupied for 1 or 2 years by the Sierra Nevada Earthscope Project (SNEP) and about 15 Earthscope Transportable Array (TA) stations in the region of the Sierra. With the SNEP footprint, stations are spaced about 25 km apart and extend roughly 400 km along the range and 150 km normal to the range. Additional TA stations extend the aperture of the array to about 600 km. Events were chosen to get the best signal-to-noise ratio while optimizing the backazimuthal coverage. P- wave arrival times were determined simultaneously across all stations for each event using a waveform correlation technique developed by G. Pavlis (dbxcor). Initial examination of the travel-time residuals indicates that no substantial lithospheric downwelling exists between the previously recognized "Isabella anomaly" at the southern end of the range and the approximate position of the south edge of the Gorda plate. Residuals in the Basin and Range are generally small but consistently late compared to stations to the west, but large differences in residuals (>1 s) in the western Sierran foothills can occur over short (~50 km) distances, suggesting substantial heterogeneity in the crust or uppermost mantle. Results of a 3-D isotropic inversion will be presented, and any systematic residual patterns remaining will be evaluated with an eye towards identifying any anisotropy.

  9. Is the closest facility the one actually used? An assessment of travel time estimation based on mammography facilities.

    Science.gov (United States)

    Alford-Teaster, Jennifer; Lange, Jane M; Hubbard, Rebecca A; Lee, Christoph I; Haas, Jennifer S; Shi, Xun; Carlos, Heather A; Henderson, Louise; Hill, Deirdre; Tosteson, Anna N A; Onega, Tracy

    2016-02-18

    Characterizing geographic access depends on a broad range of methods available to researchers and the healthcare context to which the method is applied. Globally, travel time is one frequently used measure of geographic access with known limitations associated with data availability. Specifically, due to lack of available utilization data, many travel time studies assume that patients use the closest facility. To examine this assumption, an example using mammography screening data, which is considered a geographically abundant health care service in the United States, is explored. This work makes an important methodological contribution to measuring access--which is a critical component of health care planning and equity almost everywhere. We analyzed one mammogram from each of 646,553 women participating in the US based Breast Cancer Surveillance Consortium for years 2005-2012. We geocoded each record to street level address data in order to calculate travel time to the closest and to the actually used mammography facility. Travel time between the closest and the actual facility used was explored by woman-level and facility characteristics. Only 35% of women in the study population used their closest facility, but nearly three-quarters of women not using their closest facility used a facility within 5 min of the closest facility. Individuals that by-passed the closest facility tended to live in an urban core, within higher income neighborhoods, or in areas where the average travel times to work was longer. Those living in small towns or isolated rural areas had longer closer and actual median drive times. Since the majority of US women accessed a facility within a few minutes of their closest facility this suggests that distance to the closest facility may serve as an adequate proxy for utilization studies of geographically abundant services like mammography in areas where the transportation networks are well established.

  10. The influence of travel time on emergency obstetric care seeking behavior in the urban poor of Bangladesh: a GIS study.

    Science.gov (United States)

    Panciera, Rocco; Khan, Akib; Rizvi, Syed Jafar Raza; Ahmed, Shakil; Ahmed, Tanvir; Islam, Rubana; Adams, Alayne M

    2016-08-22

    Availability of Emergency Obstetric Care (EmOC) is crucial to avert maternal death due to life-threatening complications potentially arising during delivery. Research on the determinants of utilization of EmOC has neglected urban settings, where traffic congestion can pose a significant barrier to the access of EmOC facilities, particularly for the urban poor due to costly and limited transportation options. This study investigates the impact of travel time to EmOC facilities on the utilization of facility-based delivery services among mothers living in urban poor settlements in Sylhet, Bangladesh. A cross-sectional EmOC health-seeking behavior survey from 39 poor urban clusters was geo-spatially linked to a comprehensive geo-referenced dataset of EmOC facility locations. Geo-spatial techniques and logistic regression were then applied to quantify the impact of travel time on place of delivery (EmOC facility or home), while controlling for confounding socio-cultural and economic factors. Increasing travel time to the nearest EmOC facility is found to act as a strong deterrent to seeking care for the urban poor in Sylhet. Logistic regression results indicate that a 5-min increase in travel time to the nearest EmOC facility is associated with a 30 % decrease (0.655 odds ratio, 95 % CI: 0.529-0.811) in the likelihood of delivery at an EmOC facility rather than at home. Moreover, the impact of travel time varies substantially between public, NGO and private facilities. A 5-min increase in travel time from a private EmOC facility is associated with a 32.9 % decrease in the likelihood of delivering at a private facility, while for public and Non-Government Organizations (NGO) EmOC facilities, the impact is lower (28.2 and 28.6 % decrease respectively). Other strong determinants of delivery at an EmOC facility are the use of antenatal care and mother's formal education, while Muslim mothers are found to be more likely to deliver at home. Geospatial evidence points to

  11. Acoustic travel time gauges for in-situ determination of pressure and temperature in multi-anvil apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xuebing; Chen, Ting; Qi, Xintong [Department of Geosciences, Stony Brook University, Stony Brook, New York 11794 (United States); Zou, Yongtao; Liebermann, Robert C.; Li, Baosheng [Mineral Physics Institute, Stony Brook University, Stony Brook, New York 11794 (United States); Kung, Jennifer [Department of Earth Sciences, National Cheng Kung University, Tainan 70101, Taiwan (China); Yu, Tony; Wang, Yanbin [GeoSoilEnviroCARS, Center for Advanced Radiation Sources, The University of Chicago, 5640 S. Ellis Avenue, Chicago, Illinois 60637 (United States)

    2015-08-14

    In this study, we developed a new method for in-situ pressure determination in multi-anvil, high-pressure apparatus using an acoustic travel time approach within the framework of acoustoelasticity. The ultrasonic travel times of polycrystalline Al{sub 2}O{sub 3} were calibrated against NaCl pressure scale up to 15 GPa and 900 °C in a Kawai-type double-stage multi-anvil apparatus in conjunction with synchrotron X-radiation, thereby providing a convenient and reliable gauge for pressure determination at ambient and high temperatures. The pressures derived from this new travel time method are in excellent agreement with those from the fixed-point methods. Application of this new pressure gauge in an offline experiment revealed a remarkable agreement of the densities of coesite with those from the previous single crystal compression studies under hydrostatic conditions, thus providing strong validation for the current travel time pressure scale. The travel time approach not only can be used for continuous in-situ pressure determination at room temperature, high temperatures, during compression and decompression, but also bears a unique capability that none of the previous scales can deliver, i.e., simultaneous pressure and temperature determination with a high accuracy (±0.16 GPa in pressure and ±17 °C in temperature). Therefore, the new in-situ Al{sub 2}O{sub 3} pressure gauge is expected to enable new and expanded opportunities for offline laboratory studies of solid and liquid materials under high pressure and high temperature in multi-anvil apparatus.

  12. Acoustic travel time gauges for in-situ determination of pressure and temperature in multi-anvil apparatus

    International Nuclear Information System (INIS)

    Wang, Xuebing; Chen, Ting; Qi, Xintong; Zou, Yongtao; Liebermann, Robert C.; Li, Baosheng; Kung, Jennifer; Yu, Tony; Wang, Yanbin

    2015-01-01

    In this study, we developed a new method for in-situ pressure determination in multi-anvil, high-pressure apparatus using an acoustic travel time approach within the framework of acoustoelasticity. The ultrasonic travel times of polycrystalline Al 2 O 3 were calibrated against NaCl pressure scale up to 15 GPa and 900 °C in a Kawai-type double-stage multi-anvil apparatus in conjunction with synchrotron X-radiation, thereby providing a convenient and reliable gauge for pressure determination at ambient and high temperatures. The pressures derived from this new travel time method are in excellent agreement with those from the fixed-point methods. Application of this new pressure gauge in an offline experiment revealed a remarkable agreement of the densities of coesite with those from the previous single crystal compression studies under hydrostatic conditions, thus providing strong validation for the current travel time pressure scale. The travel time approach not only can be used for continuous in-situ pressure determination at room temperature, high temperatures, during compression and decompression, but also bears a unique capability that none of the previous scales can deliver, i.e., simultaneous pressure and temperature determination with a high accuracy (±0.16 GPa in pressure and ±17 °C in temperature). Therefore, the new in-situ Al 2 O 3 pressure gauge is expected to enable new and expanded opportunities for offline laboratory studies of solid and liquid materials under high pressure and high temperature in multi-anvil apparatus

  13. Upper and Middle Tiete River Basin dam-hydraulic system, travel time and temperature modeling

    Science.gov (United States)

    Devkota, Bishnu; Imberger, Jörg

    2012-12-01

    SummaryTiete River System in the State of Sao Paolo, Brazil is characterized by complex hydraulics and operational problems due to series of dams and point and diffuse inflows along the river. A one dimension Lagrangian river model was developed and applied to the 313 km reach of the Upper and Middle Tiete River Basin from the Penha Dam to the head water of Bara Bonita Reservoir, a stretch of river that includes six small to medium size dams (3.4-22 m high) including the Pirapora Reservoir and 26 inflows into the river (11 tributaries, 9 diffuse source areas, and discharges of 4 cities stormwater and 2 wastewater treatment plants. The conservative tracer transport and temperature model that accounts for the short and long wave radiation and heat transfers at the free surface was included and solved using the Crank-Nicholson scheme. The time variable catchment input to the model was the simulated output of the external hydrological model called Runoff Load Model which results were provided by CETESB. The numerical treatment of series of dams and spillway (that included uncontrolled overflow spillway, gate-controlled ogee spillway; and underflow gates and tunnels) and parameterisation of hydraulic jumps are described. Special attention was focused on the high spatial and temporal variation of flows in Tiete River Basin, a result of the large variation in catchment inflows and channel geometry due to dams and reservoirs along the river. Predicted and measured spatial and seasonal variation of flow and temperature profiles along the river show good agreement. The simulated travel time of conservative tracer is compared against the CETESB's 1982 and 1984 field study data in a 254 km reach of the Middle Tiete River that again shows good agreement. Being Lagrangian in construction, this new model is computationally efficient making it an ideal tool for long term simulation for water resource planning, management and operation decision making in a large and complex river

  14. Monitoring the impact of decentralised chronic care services on patient travel time in rural Africa - methods and results in Northern Malawi

    Directory of Open Access Journals (Sweden)

    Houben Rein MGJ

    2012-11-01

    Full Text Available Abstract Background Decentralised health services form a key part of chronic care strategies in resource-limited settings by reducing the distance between patient and clinic and thereby the time and costs involved in travelling. However, few tools exist to evaluate the impact of decentralisation on patient travel time or what proportion of patients attend their nearest clinic. Here we develop methods to monitor changes in travel time, using data from the antiretroviral therapy (ART roll-out in a rural district in North Malawi. Methods Clinic position was combined with GPS information on the home village of patients accessing ART services in Karonga District (North Malawi between July 2005 and July 2009. Potential travel time was estimated as the travel time for an individual attending their nearest clinic, and estimated actual travel time as the time to the clinic attended. This allowed us to calculate changes in potential and actual travel time as new clinics opened and track the proportion and origin of patients not accessing their nearest clinic. Results The model showed how the opening of further ART clinics in Karonga District reduced median potential travel time from 83 to 43 minutes, and median actual travel time fell from 83 to 47 minutes. The proportion of patients not attending their nearest clinic increased from 6% when two clinics were open, to 12% with four open. Discussion Integrating GPS information with patient data shows the impact of decentralisation on travel time and clinic choice to inform policy and research questions. In our case study, travel time decreased, accompanied by an increased uptake of services. However, the model also identified an increasing proportion of ART patients did not attend their nearest clinic.

  15. Monitoring the impact of decentralised chronic care services on patient travel time in rural Africa--methods and results in Northern Malawi.

    Science.gov (United States)

    Houben, Rein M G J; Van Boeckel, Thomas P; Mwinuka, Venance; Mzumara, Peter; Branson, Keith; Linard, Catherine; Chimbwandira, Frank; French, Neil; Glynn, Judith R; Crampin, Amelia C

    2012-11-15

    Decentralised health services form a key part of chronic care strategies in resource-limited settings by reducing the distance between patient and clinic and thereby the time and costs involved in travelling. However, few tools exist to evaluate the impact of decentralisation on patient travel time or what proportion of patients attend their nearest clinic. Here we develop methods to monitor changes in travel time, using data from the antiretroviral therapy (ART) roll-out in a rural district in North Malawi. Clinic position was combined with GPS information on the home village of patients accessing ART services in Karonga District (North Malawi) between July 2005 and July 2009. Potential travel time was estimated as the travel time for an individual attending their nearest clinic, and estimated actual travel time as the time to the clinic attended. This allowed us to calculate changes in potential and actual travel time as new clinics opened and track the proportion and origin of patients not accessing their nearest clinic. The model showed how the opening of further ART clinics in Karonga District reduced median potential travel time from 83 to 43 minutes, and median actual travel time fell from 83 to 47 minutes. The proportion of patients not attending their nearest clinic increased from 6% when two clinics were open, to 12% with four open. Integrating GPS information with patient data shows the impact of decentralisation on travel time and clinic choice to inform policy and research questions. In our case study, travel time decreased, accompanied by an increased uptake of services. However, the model also identified an increasing proportion of ART patients did not attend their nearest clinic.

  16. Playing with Game Time: Auto-Saves and Undoing Despite the ‘Magic Circle’

    Directory of Open Access Journals (Sweden)

    Chuk Moran

    2010-07-01

    Full Text Available Typically the time of games played on computer systems is considered as linear and progressive. Those studying games talk this way and often linear time is the idiom by which players make sense of their experiences at play. This article focuses on some recent games that explicitly engage players with time, a practice that I argue highlights the complicated relationship between the player, game time, and clock time. It is common to treat videogames as exception from the world, bounded in a kind of “magic circle” (Huizinga, 1938/1955. This can be seen in the most ready explanation of time; the basically uninterrupted arrow of player progress through the space of the game, made canonical by Jesper Juul (2005. However, there are many other kinds of time in games, and how players use these times says something significant about a game. There is something more to the magic circle than a condition of pure interiority. The magic circle is play that situates a game and it hosts a special intensity opening to larger forces. This is often ignored in the contemporary use of the term in scholarly discussions of computer-based games. The overly respectful attitude that games are distinct from regular life results in the construction of a “pure” zone strictly internal to games, and time in this zone appears as a line. This article argues that such a vision is incomplete. Time in videogames need not be understood as a single line, or any diagram of lines at all. The complex and overlapping rhythms that crosscut everyday life do not stop at a magical barrier that contains and protects the game; these varied rhythms both influence how games are played, and describe the variety of times that games contain. By attending to other times than a line, we can recognize other patterns in gaming. I suggest that the act of undoing highlights this particular temporal intensity of videogames. In this paper, I argue that undoing is not simply the restoration of a

  17. Microwave Heating: A Time Saving Technology or a Way to Induce Vegetable Oils Oxidation?

    OpenAIRE

    Malheiro, Ricardo; Casal, Susana; Ramalhosa, Elsa; Pereira, José Alberto

    2011-01-01

    Microwave heating features modern lifestyle. The use of this technology enables a significant reduction in the time dedicated to prepare meals and opens new perspectives at the industrial level. In this chapter we report the combined effect of time/applied potency of microwave heating in comparison to conventional electric oven on the quality of vegetable oils. In general, the degradation pattern of vegetable oils under microwave heating was similar to that expected from other...

  18. Author-based journal selection system that helps authors save time in article submission.

    Science.gov (United States)

    Ozturk, Onur; Ileri, Fatih

    2018-01-01

    Submission to journals takes a lot of time and format related submission requirements vary greatly from one journal to another. Lack of time and motivation in academia reduces scientific outputs and demotivates researchers. Author-based journal selection system (ABJSS) is a platform for pooling manuscripts conceived to minimize the time spent for manuscript submission and to increase scientific output. The system will provide two types of account: "Author" and "Journal Administrator". Each account type will have its own abilities and permissions. The ABJJS system is an ongoing project that will be designed in cooperation with IT experts and academicians and it will be presented to the scientific world as soon as it secures sufficient support.

  19. A global map of travel time to cities to assess inequalities in accessibility in 2015

    Science.gov (United States)

    Weiss, D. J.; Nelson, A.; Gibson, H. S.; Temperley, W.; Peedell, S.; Lieber, A.; Hancher, M.; Poyart, E.; Belchior, S.; Fullman, N.; Mappin, B.; Dalrymple, U.; Rozier, J.; Lucas, T. C. D.; Howes, R. E.; Tusting, L. S.; Kang, S. Y.; Cameron, E.; Bisanzio, D.; Battle, K. E.; Bhatt, S.; Gething, P. W.

    2018-01-01

    The economic and man-made resources that sustain human wellbeing are not distributed evenly across the world, but are instead heavily concentrated in cities. Poor access to opportunities and services offered by urban centres (a function of distance, transport infrastructure, and the spatial distribution of cities) is a major barrier to improved livelihoods and overall development. Advancing accessibility worldwide underpins the equity agenda of ‘leaving no one behind’ established by the Sustainable Development Goals of the United Nations. This has renewed international efforts to accurately measure accessibility and generate a metric that can inform the design and implementation of development policies. The only previous attempt to reliably map accessibility worldwide, which was published nearly a decade ago, predated the baseline for the Sustainable Development Goals and excluded the recent expansion in infrastructure networks, particularly in lower-resource settings. In parallel, new data sources provided by Open Street Map and Google now capture transportation networks with unprecedented detail and precision. Here we develop and validate a map that quantifies travel time to cities for 2015 at a spatial resolution of approximately one by one kilometre by integrating ten global-scale surfaces that characterize factors affecting human movement rates and 13,840 high-density urban centres within an established geospatial-modelling framework. Our results highlight disparities in accessibility relative to wealth as 50.9% of individuals living in low-income settings (concentrated in sub-Saharan Africa) reside within an hour of a city compared to 90.7% of individuals in high-income settings. By further triangulating this map against socioeconomic datasets, we demonstrate how access to urban centres stratifies the economic, educational, and health status of humanity.

  20. Just-in-Time to Save Lives: A Pilot Study of Layperson Tourniquet Application.

    Science.gov (United States)

    Goolsby, Craig; Branting, Andrew; Chen, Elizabeth; Mack, Erin; Olsen, Cara

    2015-09-01

    The objective was to determine whether just-in-time (JiT) instructions increase successful tourniquet application by laypersons. This was a randomized pilot study conducted in August 2014. The study occurred at the Uniformed Services University campus in Bethesda, Maryland. A total of 194 volunteers without prior military service or medical training completed the study. The participant stood in front of a waist-down mannequin that had an exposed leg. An observer read a scenario card aloud that described a mass casualty event. The observer then asked the participant to apply a Combat Application Tourniquet (C-A-T) to the mannequin. Test participants received a 4 × 6-inch card, with JiT instructions, in addition to their C-A-T; controls received no instructions. Participants were randomized in a 3:1 ratio of instructions to no instructions. The study's primary outcome was the proportion of successfully applied tourniquets by participants receiving JiT instructions compared to participants not receiving instructions. Secondary outcomes included the time for successful tourniquet placement, reasons for failed tourniquet application, and participants' self-reported willingness and comfort using tourniquets in real-life settings. Just-in-time instructions more than doubled successful tourniquet placement. Participants supplied with JiT instructions placed a tourniquet successfully 44.14% of the time, compared to 20.41% of the time for controls without instructions (risk ratio = 2.16; 95% confidence interval = 1.21 to 3.87; p = 0.003). Just-in-time instructions increase laypeople's successful application of C-A-T. This pilot study provides evidence that JiT instructions may assist the lay public in providing effective point-of-injury hemorrhage control. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.