WorldWideScience

Sample records for waiting time algorithm

  1. Wait times in Canada.

    Science.gov (United States)

    MacKinnon, Janice Christine

    2017-07-01

    A significant barrier to accessing healthcare in Canada is long waiting lists, which can be linked to the way that Medicare was structured. After significant pressure, provincial governments began to address wait times. An example of a successful strategy to reduce wait times for elective surgery is the Saskatchewan Surgical Initiative, which saw wait times in the province change from being among the longest in Canada to the shortest.

  2. ADAPTATION OF JOHNSON SEQUENCING ALGORITHM FOR JOB SCHEDULING TO MINIMISE THE AVERAGE WAITING TIME IN CLOUD COMPUTING ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    SOUVIK PAL

    2016-09-01

    Full Text Available Cloud computing is an emerging paradigm of Internet-centric business computing where Cloud Service Providers (CSPs are providing services to the customer according to their needs. The key perception behind cloud computing is on-demand sharing of resources available in the resource pool provided by CSP, which implies new emerging business model. The resources are provisioned when jobs arrive. The job scheduling and minimization of waiting time are the challenging issue in cloud computing. When a large number of jobs are requested, they have to wait for getting allocated to the servers which in turn may increase the queue length and also waiting time. This paper includes system design for implementation which is concerned with Johnson Scheduling Algorithm that provides the optimal sequence. With that sequence, service times can be obtained. The waiting time and queue length can be reduced using queuing model with multi-server and finite capacity which improves the job scheduling model.

  3. Waiting time distribution in M/D/1 queueing systems

    DEFF Research Database (Denmark)

    Iversen, Villy Bæk; Staalhagen, Lars

    1999-01-01

    The well-known formula for the waiting time distribution of M/D/1 queueing systems is numerically unsuitable when the load is close to 1.0 and/or the results for a large waiting time are required. An algorithm for any load and waiting time is presented, based on the state probabilities of M/D/1...

  4. Bell inequalities and waiting times

    Energy Technology Data Exchange (ETDEWEB)

    Poeltl, Christina; Governale, Michele [School of Chemical and Physical Sciences and MacDiarmid Institute for Advanced Materials and Nanotechnology, Victoria University of Wellington, PO Box 600, Wellington 6140 (New Zealand)

    2015-07-01

    We propose a Bell test based on waiting time distributions for spin entangled electron pairs, which are generated and split in mesoscopic Coulomb blockade structures, denoted as entanglers. These systems have the advantage that quantum point contacts enable a time resolved observation of the electrons occupying the system, which gives access to quantities such as full counting statistics and waiting time distributions. We use the partial waiting times to define a CHSH-Bell test, which is a purely electronic analogue of the test used in quantum optics. After the introduction of the Bell inequality we discuss the findings on the two examples of a double quantum dot and a triple quantum dot. This Bell test allows the exclusion of irrelevant tunnel processes from the statistics normally used for the Bell correlations. This can improve the parameter range for which a violation of the Bell inequality can be measured significantly.

  5. 46 CFR 9.10 - Waiting time.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Waiting time. 9.10 Section 9.10 Shipping COAST GUARD... § 9.10 Waiting time. The same construction should be given the act when charging for waiting time as... for duty the waiting time amounts to at least one hour. ...

  6. Waiting time guarantee - an update

    DEFF Research Database (Denmark)

    Socha, Karolina; Bech, Mickael

    2008-01-01

    The rule of extended free choice of hospital, in force since 2002, provides patients with an option to choose a private hospital if the public system is unable to provide a treatment within the guaranteed waiting time of one month. In June 2008 the Government declared in their yearly budget agree...

  7. Advertising Emergency Department Wait Times

    OpenAIRE

    Weiner, Scott G

    2013-01-01

    Advertising emergency department (ED) wait times has become a common practice in the United States. Proponents of this practice state that it is a powerful marketing strategy that can help steer patients to the ED. Opponents worry about the risk to the public health that arises from a patient with an emergent condition self-triaging to a further hospital, problems with inaccuracy and lack of standard definition of the reported time, and directing lower acuity patients to the higher cost ED se...

  8. Advertising emergency department wait times.

    Science.gov (United States)

    Weiner, Scott G

    2013-03-01

    Advertising emergency department (ED) wait times has become a common practice in the United States. Proponents of this practice state that it is a powerful marketing strategy that can help steer patients to the ED. Opponents worry about the risk to the public health that arises from a patient with an emergent condition self-triaging to a further hospital, problems with inaccuracy and lack of standard definition of the reported time, and directing lower acuity patients to the higher cost ED setting instead to primary care. Three sample cases demonstrating the pitfalls of advertising ED wait times are discussed. Given the lack of rigorous evidence supporting the practice and potential adverse effects to the public health, caution about its use is advised.

  9. Advertising Emergency Department Wait Times

    Science.gov (United States)

    Weiner, Scott G.

    2013-01-01

    Advertising emergency department (ED) wait times has become a common practice in the United States. Proponents of this practice state that it is a powerful marketing strategy that can help steer patients to the ED. Opponents worry about the risk to the public health that arises from a patient with an emergent condition self-triaging to a further hospital, problems with inaccuracy and lack of standard definition of the reported time, and directing lower acuity patients to the higher cost ED setting instead to primary care. Three sample cases demonstrating the pitfalls of advertising ED wait times are discussed. Given the lack of rigorous evidence supporting the practice and potential adverse effects to the public health, caution about its use is advised. PMID:23599836

  10. Advertising Emergency Department Wait Times

    Directory of Open Access Journals (Sweden)

    Scott G. Weiner

    2013-03-01

    Full Text Available Advertising emergency department (ED wait times has become a common practice in the UnitedStates. Proponents of this practice state that it is a powerful marketing strategy that can help steerpatients to the ED. Opponents worry about the risk to the public health that arises from a patient withan emergent condition self-triaging to a further hospital, problems with inaccuracy and lack of standarddefinition of the reported time, and directing lower acuity patients to the higher cost ED setting insteadto primary care. Three sample cases demonstrating the pitfalls of advertising ED wait times arediscussed. Given the lack of rigorous evidence supporting the practice and potential adverse effects tothe public health, caution about its use is advised

  11. Two Effective Ways to Implement Wait Time. A Symposium on Wait Time.

    Science.gov (United States)

    Swift, J. Nathan; And Others

    The effects of instructional guides and a wait time feedback device (called a "Wait Timer") on the classroom interaction of middle school science teachers are examined. The Wait Timer, an unobtrusive indicator of wait time, is an automatic device that activates a light when a person speaks. The duration of the light at the end of a…

  12. Queues with waiting time dependent service

    DEFF Research Database (Denmark)

    Bekker, R.; Koole, G. M.; Nielsen, Bo Friis

    2011-01-01

    Motivated by service levels in terms of the waiting-time distribution seen, for instance, in call centers, we consider two models for systems with a service discipline that depends on the waiting time. The first model deals with a single server that continuously adapts its service rate based...... derive steady-state waiting-time distributions for both models. The results are illustrated with numerical examples....... on the waiting time of the first customer in line. In the second model, one queue is served by a primary server which is supplemented by a secondary server when the waiting of the first customer in line exceeds a threshold. Using level crossings for the waiting-time process of the first customer in line, we...

  13. Can We Predict Patient Wait Time?

    Science.gov (United States)

    Pianykh, Oleg S; Rosenthal, Daniel I

    2015-10-01

    The importance of patient wait-time management and predictability can hardly be overestimated: For most hospitals, it is the patient queues that drive and define every bit of clinical workflow. The objective of this work was to study the predictability of patient wait time and identify its most influential predictors. To solve this problem, we developed a comprehensive list of 25 wait-related parameters, suggested in earlier work and observed in our own experiments. All parameters were chosen as derivable from a typical Hospital Information System dataset. The parameters were fed into several time-predicting models, and the best parameter subsets, discovered through exhaustive model search, were applied to a large sample of actual patient wait data. We were able to discover the most efficient wait-time prediction factors and models, such as the line-size models introduced in this work. Moreover, these models proved to be equally accurate and computationally efficient. Finally, the selected models were implemented in our patient waiting areas, displaying predicted wait times on the monitors located at the front desks. The limitations of these models are also discussed. Optimal regression models based on wait-line sizes can provide accurate and efficient predictions for patient wait time. Copyright © 2015 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  14. Improving Patient Satisfaction with Waiting Time

    Science.gov (United States)

    Eilers, Gayleen M.

    2004-01-01

    Waiting times are a significant component of patient satisfaction. A patient satisfaction survey performed in the author's health center showed that students rated waiting time lowest of the listed categories--A ratings of 58% overall, 63% for scheduled appointments, and 41% for the walk-in clinic. The center used a quality improvement process and…

  15. Factors of Perceived Waiting Time and Implications on Passengers’ Satisfaction with Waiting Time

    Directory of Open Access Journals (Sweden)

    Shumin Feng

    2016-04-01

    Full Text Available In order to explore the influence factors on perceived waiting time, a multiple linear regression model has been used to quantitatively describe the relationship between perceived waiting time and various factors. The model is established with 234 data, which is surveyed with questionnaire at three stops in Harbin, China. The results show that several certain factors (“trip purpose - where to”, “presence of a companion - whether one has a companion or not”, “having a timing device - whether one has a timing device or not”, “riding frequency - how many times one takes one line per week” and “waiting behaviour - what one does while waiting for a bus” have significant influence on perceived waiting time, which confirms previous findings and supports transferability of results. The significance of “waiting mood - howabout the mood while waiting for a bus” and “reserved waiting time - how long one will wait” are confirmed for the first time in this study. In contrast to previous studies, “waiting time interval - for how long in one day” is a negative variable and socioeconomic variables are non-significant. And it is found that the relationship between perceived waiting time and passengers’ satisfaction with the waiting time follows a decreasing exponential distribution. With this model, the variation trend of the section, where passenger satisfaction value is larger than 0 is obviously steeper than the section smaller than 0. Such result proves that passenger mood with short waiting time is more sensitive than with longer waiting time. And the borderline perceived waiting time, distinguishing satisfied from dissatisfied passengers is proven to be 7.87 minutes when assignment interval of satisfaction is (-25.25], when satisfaction is positive (larger than 0, the accuracy being 70.30%, while the accuracy is 82.71% fornegative satisfaction (less than 0.

  16. Stochastic nature of series of waiting times

    Science.gov (United States)

    Anvari, Mehrnaz; Aghamohammadi, Cina; Dashti-Naserabadi, H.; Salehi, E.; Behjat, E.; Qorbani, M.; Khazaei Nezhad, M.; Zirak, M.; Hadjihosseini, Ali; Peinke, Joachim; Tabar, M. Reza Rahimi

    2013-06-01

    Although fluctuations in the waiting time series have been studied for a long time, some important issues such as its long-range memory and its stochastic features in the presence of nonstationarity have so far remained unstudied. Here we find that the “waiting times” series for a given increment level have long-range correlations with Hurst exponents belonging to the interval 1/2waiting time distribution. We find that the logarithmic difference of waiting times series has a short-range correlation, and then we study its stochastic nature using the Markovian method and determine the corresponding Kramers-Moyal coefficients. As an example, we analyze the velocity fluctuations in high Reynolds number turbulence and determine the level dependence of Markov time scales, as well as the drift and diffusion coefficients. We show that the waiting time distributions exhibit power law tails, and we were able to model the distribution with a continuous time random walk.

  17. WAITING TIME IN THE WAITING ROOM IN FAMILY PRACTICE AND PATIENT SATISFACTION

    Directory of Open Access Journals (Sweden)

    Janko Kersnik

    2001-05-01

    Full Text Available Background: Appointment system shortens the waiting time in the waiting room for the patient and allows better use of time for the doctor. We wanted to examine how long patients are willing to wait in the waiting room, how long they waited at the last visit, patient satisfaction with the last visit, the satisfaction with the length of waiting in the past 12 months and the overall patient satisfaction score for the last 12 months. Appointment system proved to be effective means of organising practice time. Waiting time in the waiting room with appointment system was considerably shorter (mean 18.5 minutes as compared to the waiting time in the practices without appointment system (mean 55.4 minutes, the fact which is reflected also in higher satisfaction with waiting in the waiting room in the past 12 months. Three quarters of patients in practices with appointment system waited standard 20 minutes or less, as opposed to the other practices where only one quarter of patients waited 20 minutes or less.Conclusions: The overall satisfaction with the doctor with the appointment system does not differ in both types of practices. The patients from practices with appointment system evaluated better possibility to get an appointment to suit the patients, but worse help of the doctors’ staff, possibility to get through to the office by phone, the length of time during the consultation and the doctors’ thoroughness.

  18. Worth the wait? How restaurant waiting time influences customer behavior and revenue

    NARCIS (Netherlands)

    de Vries, J.; Roy, Debjit; De Koster, Rene

    2018-01-01

    In many service industries, customers have to wait for service. When customers have a choice, this waiting may influence their service experience, sojourn time, and ultimately spending, reneging, and return behavior. Not much is known however, about the system-wide impact of waiting on customer

  19. Time while waiting: patients' experiences of scheduled surgery.

    Science.gov (United States)

    Carr, Tracey; Teucher, Ulrich C; Casson, Alan G

    2014-12-01

    Research on patients' experiences of wait time for scheduled surgery has centered predominantly on the relative tolerability of perceived wait time and impacts on quality of life. We explored patients' experiences of time while waiting for three types of surgery with varied wait times--hip or knee replacement, shoulder surgery, and cardiac surgery. Thirty-two patients were recruited by their surgeons. We asked participants about their perceptions of time while waiting in two separate interviews. Using interpretative phenomenological analysis (IPA), we discovered connections between participant suffering, meaningfulness of time, and agency over the waiting period and the lived duration of time experience. Our findings reveal that chronological duration is not necessarily the most relevant consideration in determining the quality of waiting experience. Those findings helped us create a conceptual framework for lived wait time. We suggest that clinicians and policy makers consider the complexity of wait time experience to enhance preoperative patient care. © The Author(s) 2014.

  20. Sustainability: orthopaedic surgery wait time management strategies.

    Science.gov (United States)

    Amar, Claudia; Pomey, Marie-Pascale; SanMartin, Claudia; De Coster, Carolyn; Noseworthy, Tom

    2015-01-01

    The purpose of this paper is to examine Canadian organizational and systemic factors that made it possible to keep wait times within federally established limits for at least 18 months. The research design is a multiple cases study. The paper selected three cases: Case 1 - staff were able to maintain compliance with requirements for more than 18 months; Case 2 - staff were able to meet requirements for 18 months, but unable to sustain this level; Case 3 - staff were never able to meet the requirements. For each case the authors interviewed persons involved in the strategies and collected documents. The paper analysed systemic and organizational-level factors; including governance and leadership, culture, resources, methods and tools. Findings indicate that the hospital that was able to maintain compliance with the wait time requirements had specific characteristics: an exclusive mandate to do only hip and knee replacement surgery; motivated staff who were not distracted by other concerns; and a strong team spirit. The authors' research highlights an important gradient between three cases regarding the factors that sustain waiting times. The paper show that the hospital factory model seems attractive in a super-specialized surgery context. However, patients are selected for simple surgeries, without complications, and so this cannot be considered a unique model.

  1. SU-F-P-20: Predicting Waiting Times in Radiation Oncology Using Machine Learning

    International Nuclear Information System (INIS)

    Joseph, A; Herrera, D; Hijal, T; Kildea, J; Hendren, L; Leung, A; Wainberg, J; Sawaf, M; Gorshkov, M; Maglieri, R; Keshavarz, M

    2016-01-01

    Purpose: Waiting times remain one of the most vexing patient satisfaction challenges facing healthcare. Waiting time uncertainty can cause patients, who are already sick or in pain, to worry about when they will receive the care they need. These waiting periods are often difficult for staff to predict and only rough estimates are typically provided based on personal experience. This level of uncertainty leaves most patients unable to plan their calendar, making the waiting experience uncomfortable, even painful. In the present era of electronic health records (EHRs), waiting times need not be so uncertain. Extensive EHRs provide unprecedented amounts of data that can statistically cluster towards representative values when appropriate patient cohorts are selected. Predictive modelling, such as machine learning, is a powerful approach that benefits from large, potentially complex, datasets. The essence of machine learning is to predict future outcomes by learning from previous experience. The application of a machine learning algorithm to waiting time data has the potential to produce personalized waiting time predictions such that the uncertainty may be removed from the patient’s waiting experience. Methods: In radiation oncology, patients typically experience several types of waiting (eg waiting at home for treatment planning, waiting in the waiting room for oncologist appointments and daily waiting in the waiting room for radiotherapy treatments). A daily treatment wait time model is discussed in this report. To develop a prediction model using our large dataset (with more than 100k sample points) a variety of machine learning algorithms from the Python package sklearn were tested. Results: We found that the Random Forest Regressor model provides the best predictions for daily radiotherapy treatment waiting times. Using this model, we achieved a median residual (actual value minus predicted value) of 0.25 minutes and a standard deviation residual of 6.5 minutes

  2. SU-F-P-20: Predicting Waiting Times in Radiation Oncology Using Machine Learning

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, A; Herrera, D; Hijal, T; Kildea, J [McGill University Health Centre, Montreal, Quebec (Canada); Hendren, L; Leung, A; Wainberg, J; Sawaf, M; Gorshkov, M; Maglieri, R; Keshavarz, M [McGill University, Montreal, Quebec (Canada)

    2016-06-15

    Purpose: Waiting times remain one of the most vexing patient satisfaction challenges facing healthcare. Waiting time uncertainty can cause patients, who are already sick or in pain, to worry about when they will receive the care they need. These waiting periods are often difficult for staff to predict and only rough estimates are typically provided based on personal experience. This level of uncertainty leaves most patients unable to plan their calendar, making the waiting experience uncomfortable, even painful. In the present era of electronic health records (EHRs), waiting times need not be so uncertain. Extensive EHRs provide unprecedented amounts of data that can statistically cluster towards representative values when appropriate patient cohorts are selected. Predictive modelling, such as machine learning, is a powerful approach that benefits from large, potentially complex, datasets. The essence of machine learning is to predict future outcomes by learning from previous experience. The application of a machine learning algorithm to waiting time data has the potential to produce personalized waiting time predictions such that the uncertainty may be removed from the patient’s waiting experience. Methods: In radiation oncology, patients typically experience several types of waiting (eg waiting at home for treatment planning, waiting in the waiting room for oncologist appointments and daily waiting in the waiting room for radiotherapy treatments). A daily treatment wait time model is discussed in this report. To develop a prediction model using our large dataset (with more than 100k sample points) a variety of machine learning algorithms from the Python package sklearn were tested. Results: We found that the Random Forest Regressor model provides the best predictions for daily radiotherapy treatment waiting times. Using this model, we achieved a median residual (actual value minus predicted value) of 0.25 minutes and a standard deviation residual of 6.5 minutes

  3. Outpatient waiting time in Jos University Teaching Hospital ...

    African Journals Online (AJOL)

    Problem Long waiting time for services has been identified as a reason people avoid presenting to for care in African countries. Design Examination of causes for long outpatient waiting time and the effect of measures to reduce waiting time. Setting Outpatient department of the Jos University Teaching Hospital.

  4. Renewal processes based on generalized Mittag-Leffler waiting times

    Science.gov (United States)

    Cahoy, Dexter O.; Polito, Federico

    2013-03-01

    The fractional Poisson process has recently attracted experts from several fields of study. Its natural generalization of the ordinary Poisson process made the model more appealing for real-world applications. In this paper, we generalized the standard and fractional Poisson processes through the waiting time distribution, and showed their relations to an integral operator with a generalized Mittag-Leffler function in the kernel. The waiting times of the proposed renewal processes have the generalized Mittag-Leffler and stretched-squashed Mittag-Leffler distributions. Note that the generalizations naturally provide greater flexibility in modeling real-life renewal processes. Algorithms to simulate sample paths and to estimate the model parameters are derived. Note also that these procedures are necessary to make these models more usable in practice. State probabilities and other qualitative or quantitative features of the models are also discussed.

  5. Estimating bus passenger waiting times from incomplete bus arrivals data

    OpenAIRE

    McLeod, F.N.

    2007-01-01

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

  6. Third degree waiting time discrimination: optimal allocation of a public sector healthcare treatment under rationing by waiting.

    Science.gov (United States)

    Gravelle, Hugh; Siciliani, Luigi

    2009-08-01

    In many public healthcare systems treatments are rationed by waiting time. We examine the optimal allocation of a fixed supply of a given treatment between different groups of patients. Even in the absence of any distributional aims, welfare is increased by third degree waiting time discrimination: setting different waiting times for different groups waiting for the same treatment. Because waiting time imposes dead weight losses on patients, lower waiting times should be offered to groups with higher marginal waiting time costs and with less elastic demand for the treatment.

  7. The Effects of Immigration on NHS Waiting Times

    OpenAIRE

    Giuntella, Osea; Nicodemo, Catia; Vargas-Silva, Carlos

    2015-01-01

    This paper analyses the effects of immigration on waiting times in the National Health Service (NHS) in England. Linking administrative records from the Hospital Episode Statistics (2003-2012) with immigration data drawn from the UK Labour Force Survey, we find that immigration reduced waiting times for outpatient referrals and did not have significant effects on waiting times in Accident and Emergency (A&E) and elective care. These results are explained by the fact that immigration increases...

  8. TSA Security Checkpoint Wait Times – API (PMIS)

    Data.gov (United States)

    Department of Homeland Security — TSA operational data including: Airport wait time (hourly) data Airport throughput (hourly) data Prohibited item (hourly) data Monthly Objectives Report (MOR) data...

  9. Electron Waiting Times of a Cooper Pair Splitter

    Science.gov (United States)

    Walldorf, Nicklas; Padurariu, Ciprian; Jauho, Antti-Pekka; Flindt, Christian

    2018-02-01

    Electron waiting times are an important concept in the analysis of quantum transport in nanoscale conductors. Here we show that the statistics of electron waiting times can be used to characterize Cooper pair splitters that create spatially separated spin-entangled electrons. A short waiting time between electrons tunneling into different leads is associated with the fast emission of a split Cooper pair, while long waiting times are governed by the slow injection of Cooper pairs from a superconductor. Experimentally, the waiting time distributions can be measured using real-time single-electron detectors in the regime of slow tunneling, where conventional current measurements are demanding. Our work is important for understanding the fundamental transport processes in Cooper pair splitters and the predictions may be verified using current technology.

  10. Electron Waiting Times of a Cooper Pair Splitter

    DEFF Research Database (Denmark)

    Walldorf, Nicklas; Padurariu, Ciprian; Jauho, Antti-Pekka

    2018-01-01

    Electron waiting times are an important concept in the analysis of quantum transport in nanoscale conductors. Here we show that the statistics of electron waiting times can be used to characterize Cooper pair splitters that create spatially separated spin-entangled electrons. A short waiting time...... between electrons tunneling into different leads is associated with the fast emission of a split Cooper pair, while long waiting times are governed by the slow injection of Cooper pairs from a superconductor. Experimentally, the waiting time distributions can be measured using real-time single......-electron detectors in the regime of slow tunneling, where conventional current measurements are demanding. Our work is important for understanding the fundamental transport processes in Cooper pair splitters and the predictions may be verified using current technology....

  11. Moderate alcohol consumption and waiting time to pregnancy

    DEFF Research Database (Denmark)

    Juhl, Mette; Andersen, Anne-Marie Nybo; Grønbaek, Morten

    2001-01-01

    BACKGROUND: Recent research indicates that even a moderate consumption of alcohol in women trying to become pregnant is associated with longer waiting time to pregnancy. The findings, though, are based upon few observations. METHODS: Self-reported data on alcohol intake and waiting time to pregna...

  12. Enhancing outpatient clinics management software by reducing patients’ waiting time

    Directory of Open Access Journals (Sweden)

    Iman Almomani

    2016-11-01

    Full Text Available Summary: The Kingdom of Saudi Arabia (KSA gives great attention to improving the quality of services provided by health care sectors including outpatient clinics. One of the main drawbacks in outpatient clinics is long waiting time for patients—which affects the level of patient satisfaction and the quality of services. This article addresses this problem by studying the Outpatient Management Software (OMS and proposing solutions to reduce waiting times. Many hospitals around the world apply solutions to overcome the problem of long waiting times in outpatient clinics such as hospitals in the USA, China, Sri Lanka, and Taiwan. These clinics have succeeded in reducing wait times by 15%, 78%, 60% and 50%, respectively. Such solutions depend mainly on adding more human resources or changing some business or management policies. The solutions presented in this article reduce waiting times by enhancing the software used to manage outpatient clinics services. Both quantitative and qualitative methods have been used to understand current OMS and examine level of patient’s satisfaction. Five main problems that may cause high or unmeasured waiting time have been identified: appointment type, ticket numbering, doctor late arrival, early arriving patient and patients’ distribution list. These problems have been mapped to the corresponding OMS components. Solutions to the above problems have been introduced and evaluated analytically or by simulation experiments. Evaluation of the results shows a reduction in patient waiting time. When late doctor arrival issues are solved, this can reduce the clinic service time by up to 20%. However, solutions for early arriving patients reduces 53.3% of vital time, 20% of the clinic time and overall 30.3% of the total waiting time. Finally, well patient-distribution lists make improvements by 54.2%. Improvements introduced to the patients’ waiting time will consequently affect patients’ satisfaction and improve

  13. Parental satisfaction with paediatric care, triage and waiting times.

    Science.gov (United States)

    Fitzpatrick, Nicholas; Breen, Daniel T; Taylor, James; Paul, Eldho; Grosvenor, Robert; Heggie, Katrina; Mahar, Patrick D

    2014-04-01

    The present study aims to determine parental and guardian's perceptions of paediatric emergency care and satisfaction with care, waiting times and triage category in a community ED. A structured questionnaire was provided to parents or guardians of paediatric patients presenting to emergency. The survey evaluated parent perceptions of waiting time, environment/facilities, professionalism and communication skills of staff and overall satisfaction of care. One hundred and thirty-three completed questionnaires were received from parents of paediatric patients. Responses were overall positive with respect to the multiple domains assessed. Parents generally considered waiting times to be appropriate and consistent with triage categories. Overall satisfaction was not significantly different for varying treatment or waiting times. Patients triaged as semi-urgent were of the opinion that waiting times were less appropriate than urgent, less-urgent or non-urgent patients. On the basis of the present study, patient perceptions and overall satisfaction of care does not appear to be primarily influenced by time spent waiting or receiving treatment. Attempts made at the triage process to ensure that semi-urgent patients have reasonable expectations of waiting times might provide an opportunity to improve these patients' expectations and perceptions. © 2014 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

  14. [Influence of waiting time on patient and companion satisfaction].

    Science.gov (United States)

    Fontova-Almató, A; Juvinyà-Canal, D; Suñer-Soler, R

    2015-01-01

    To evaluate patient and companion satisfaction of a hospital Emergency Department and its relationship with waiting time. Prospective, observational study. Hospital de Figueres Emergency Department (Girona, Spain). sociodemographic characteristics, satisfaction level, real and perceived waiting time for triage and being seen by a physician. A total of 285 responses were received from patients and companions. The mean age of the patients and companions (n=257) was 54.6years (SD=18.3). The mean overall satisfaction (n=273) was 7.6 (SD=2.2). Lower perceived waiting time until nurse triage was related to higher overall satisfaction (Spearman rho (ρ)=-0.242, P<.001), and lower perceived waiting time until being seen by physician, with a higher overall satisfaction (ρ=-0.304; P<.001). Users who were informed about estimated waiting time showed higher satisfaction than those who were not informed (P=.001). Perceived waiting time and the information about estimated waiting time determined overall satisfaction. Copyright © 2014 SECA. Published by Elsevier Espana. All rights reserved.

  15. Approaching stationarity: competition between long jumps and long waiting times

    International Nuclear Information System (INIS)

    Dybiec, Bartłomiej

    2010-01-01

    Within the continuous-time random walk (CTRW) scenarios, properties of the overall motion are determined by the waiting time and the jump length distributions. In the decoupled case, with power-law distributed waiting times and jump lengths, the CTRW scenario is asymptotically described by the double (space and time) fractional Fokker–Planck equation. Properties of a system described by such an equation are determined by the subdiffusion parameter and the jump length exponent. Nevertheless, the stationary state is determined solely by the jump length distribution and the potential. The waiting time distribution determines only the rate of convergence to the stationary state. Here, we inspect the competition between long waiting times and long jumps and how this competition is reflected in the way in which a stationary state is reached. In particular, we show that the distance between a time-dependent and a stationary solution changes in time as a double power law

  16. Wait times for gastroenterology consultation in Canada: The patients’ perspective

    Science.gov (United States)

    Paterson, WG; Barkun, AN; Hopman, WM; Leddin, DJ; Paré, P; Petrunia, DM; Sewitch, MJ; Switzer, C; van Zanten, S Veldhuyzen

    2010-01-01

    Long wait times for health care have become a significant issue in Canada. As part of the Canadian Association of Gastroenterology’s Human Resource initiative, a questionnaire was developed to survey patients regarding wait times for initial gastroenterology consultation and its impact. A total of 916 patients in six cities from across Canada completed the questionnaire at the time of initial consultation. Self-reported wait times varied widely, with 26.8% of respondents reporting waiting less than two weeks, 52.4% less than one month, 77.1% less than three months, 12.5% reported waiting longer than six months and 3.6% longer than one year. One-third of patients believed their wait time was too long, with 9% rating their wait time as ‘far too long’; 96.4% believed that maximal wait time should be less than three months, 78.9% believed it should be less than one month and 40.3% believed it should be less than two weeks. Of those working or attending school, 22.6% reported missing at least one day of work or school because of their symptoms in the month before their appointment, and 9.0% reported missing five or more days in the preceding month. A total of 20.2% of respondents reported being very worried about having a serious disease (ie, scored 6 or higher on 7-point Likert scale), and 17.6% and 14.8%, respectively, reported that their symptoms caused major impairment of social functioning and with the activities of daily living. These data suggest that a significant proportion of Canadians with digestive problems are not satisfied with their wait time for gastroenterology consultation. Furthermore, while awaiting consultation, many patients experience an impaired quality of life because of their gastrointestinal symptoms. PMID:20186353

  17. Moderate alcohol consumption and waiting time to pregnancy

    DEFF Research Database (Denmark)

    Juhl, Mette; Andersen, Anne-Marie Nybo; Grønbæk, Morten

    2001-01-01

    BACKGROUND: Recent research indicates that even a moderate consumption of alcohol in women trying to become pregnant is associated with longer waiting time to pregnancy. The findings, though, are based upon few observations. METHODS: Self-reported data on alcohol intake and waiting time...... to pregnancy (0-2, 3-5, 6-12 and >12 months) was used for 39 612 pregnant women, recruited to the Danish National Birth Cohort within the first 24 weeks of pregnancy from 1997 to 2000. Main outcome measures were odds ratios (OR) for a prolonged waiting time to pregnancy according to alcohol intake. RESULTS......: In nulliparous women neither moderate nor high alcohol intake was related with longer waiting time to pregnancy compared with a low intake. In parous women, a modest association was seen only among those with an intake of >14 drinks per week (subfecundity OR 1.3; 95% confidence interval 1.0-1.7). Women who...

  18. Mean Waiting Time and Patients' Satisfaction in GOPD, Federal ...

    African Journals Online (AJOL)

    Mean Waiting Time and Patients' Satisfaction in GOPD, Federal Medical Centre, Owerri. ... Journal Home > Vol 4, No 2 (2013) > ... dis-satisfaction as noted from this study should be addressed by the staff and management of the hospital.

  19. Heart Surgery Waiting Time: Assessing the Effectiveness of an Action

    OpenAIRE

    Badakhshan, Abbas; Arab, Mohammad; Gholipour, Mahin; Behnampour, Naser; Saleki, Saeid

    2015-01-01

    Background: Waiting time is an index assessing patient satisfaction, managerial effectiveness and horizontal equity in providing health care. Although heart surgery centers establishment is attractive for politicians. They are always faced with the question of to what extent they solve patient’s problems. Objectives: The objective of this study was to evaluate factors influencing waiting time in patients of heart surgery centers, and to make recommendations for health-care policy-makers for r...

  20. The effects of immigration on NHS waiting times.

    Science.gov (United States)

    Giuntella, Osea; Nicodemo, Catia; Vargas-Silva, Carlos

    2018-03-01

    This paper analyzes the effects of immigration on waiting times for the National Health Service (NHS) in England. Linking administrative records from Hospital Episode Statistics (2003-2012) with immigration data drawn from the UK Labour Force Survey, we find that immigration reduced waiting times for outpatient referrals and did not have significant effects on waiting times in accident and emergency departments (A&E) and elective care. The reduction in outpatient waiting times can be explained by the fact that immigration increases natives' internal mobility and that immigrants tend to be healthier than natives who move to different areas. Finally, we find evidence that immigration increased waiting times for outpatient referrals in more deprived areas outside of London. The increase in average waiting times in more deprived areas is concentrated in the years immediately following the 2004 EU enlargement and disappears in the medium term (e.g., 3-4 years). Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  1. Longer wait times affect future use of VHA primary care.

    Science.gov (United States)

    Wong, Edwin S; Liu, Chuan-Fen; Hernandez, Susan E; Augustine, Matthew R; Nelson, Karin; Fihn, Stephan D; Hebert, Paul L

    2017-07-29

    Improving access to the Veterans Health Administration (VHA) is a high priority, particularly given statutory mandates of the Veterans Access, Choice and Accountability Act. This study examined whether patient-reported wait times for VHA appointments were associated with future reliance on VHA primary care services. This observational study examined 13,595 VHA patients dually enrolled in fee-for-service Medicare. Data sources included VHA administrative data, Medicare claims and the Survey of Healthcare Experiences of Patients (SHEP). Primary care use was defined as the number of face-to-face visits from VHA and Medicare in the 12 months following SHEP completion. VHA reliance was defined as the number of VHA visits divided by total visits (VHA+Medicare). Wait times were derived from SHEP responses measuring the usual number of days to a VHA appointment with patients' primary care provider for those seeking immediate care. We defined appointment wait times categorically: 0 days, 1day, 2-3 days, 4-7 days and >7 days. We used fractional logistic regression to examine the relationship between wait times and reliance. Mean VHA reliance was 88.1% (95% CI = 86.7% to 89.5%) for patients reporting 0day waits. Compared with these patients, reliance over the subsequent year was 1.4 (p = 0.041), 2.8 (p = 0.001) and 1.6 (p = 0.014) percentage points lower for patients waiting 2-3 days, 4-7 days and >7 days, respectively. Patients reporting longer usual wait times for immediate VHA care exhibited lower future reliance on VHA primary care. Longer wait times may reduce care continuity and impact cost shifting across two federal health programs. Copyright © 2017. Published by Elsevier Inc.

  2. Analysing passenger arrivals rates and waiting time at bus stops

    OpenAIRE

    Kaparias, I.; Rossetti, C.; Trozzi, V.

    2015-01-01

    The present study investigates the rather under-explored topic of passenger waiting times at public transport facilities. Using data collected from part of London’s bus network by means of physical counts, measurements and observations, and complemented by on-site passenger interviews, the waiting behaviour is analysed for a number of bus stops served by different numbers of lines. The analysis employs a wide range of statistical methods and tools, and concentrates on three aspects: passenger...

  3. What Are We Waiting For Customer Wait Time, Fill Rate, And Marine Corps Equipment Operational Availability

    Science.gov (United States)

    2016-12-01

    directed the use of Customer Wait Time (CWT) as a measure of supply chain performance (Department of Defense [DOD], 2000). CWT is defined as “the total...time elapsed between issuance of a customer order and satisfaction of the order” (United States Marine Corps [USMC], 2014, pp. 2–29). In theory...rate is a widely used metric for setting inventory levels and is also a useful measure of customer satisfaction . In general, high fill-rates can be

  4. Effect of emergency physician burnout on patient waiting times.

    Science.gov (United States)

    De Stefano, Carla; Philippon, Anne-Laure; Krastinova, Evguenia; Hausfater, Pierre; Riou, Bruno; Adnet, Frederic; Freund, Yonathan

    2018-04-01

    Burnout is common in emergency physicians. This syndrome may negatively affect patient care and alter work productivity. We seek to assess whether burnout of emergency physicians impacts waiting times in the emergency department. Prospective study in an academic ED. All patients who visited the main ED for a 4-month period in 2016 were included. Target waiting times are assigned by triage nurse to patients on arrival depending on their severity. The primary endpoint was an exceeded target waiting time for ED patients. All emergency physicians were surveyed by a psychologist to assess their level of burnout using the Maslach Burnout Inventory. We defined the level of burnout of the day in the ED as the mean burnout level of the physicians working that day (8:30 to the 8:30 the next day). A logistic regression model was performed to assess whether burnout level of the day was independently associated with prolonged waiting times, along with previously reported predictors. Target waiting time was exceeded in 7524 patients (59%). Twenty-six emergency physicians were surveyed. Median burnout score was 35 [Interquartile (24-49)]. A burnout level of the day higher than 35 was independently associated with an exceeded target waiting time (adjusted odds ratio 1.54, 95% confidence interval 1.39-1.70), together with previously reported predictors (i.e., day of the week, time of the day, trauma, age and daily census). Burnout of emergency physicians was independently associated with a prolonged waiting time for patients visiting the ED.

  5. Heart Surgery Waiting Time: Assessing the Effectiveness of an Action.

    Science.gov (United States)

    Badakhshan, Abbas; Arab, Mohammad; Gholipour, Mahin; Behnampour, Naser; Saleki, Saeid

    2015-08-01

    Waiting time is an index assessing patient satisfaction, managerial effectiveness and horizontal equity in providing health care. Although heart surgery centers establishment is attractive for politicians. They are always faced with the question of to what extent they solve patient's problems. The objective of this study was to evaluate factors influencing waiting time in patients of heart surgery centers, and to make recommendations for health-care policy-makers for reducing waiting time and increasing the quality of services from this perspective. This cross-sectional study was performed in 2013. After searching articles on PubMed, Elsevier, Google Scholar, Ovid, Magiran, IranMedex, and SID, a list of several criteria, which relate to waiting time, was provided. Afterwards, the data on waiting time were collected by a researcher-structured checklist from 156 hospitalized patients. The data were analyzed by SPSS 16. The Kolmogorov Smirnov and Shapiro tests were used for determination of normality. Due to the non-normal distribution, non-parametric tests, such as Kruskal-Wallis and Mann-Whitney were chosen for reporting significance. Parametric tests also used reporting medians. Among the studied variables, just economic status had a significant relation with waiting time (P = 0.37). Fifty percent of participants had diabetes, whereas this estimate was 43.58% for high blood pressure. As the cause of delay, 28.2% of patients reported financial problems, 18.6% personal problem and 13.5% a delay in providing equipment by the hospital. It seems the studied hospital should review its waiting time arrangements and detach them, as far as possible, from subjective and personal (specialists) decisions. On the other hand, ministries of health and insurance companies should consider more financial support. It is also recommend that hospitals should arrange preoperational psychiatric consultation for increasing patients' emotionally readiness.

  6. Improving generalized inverted index lock wait times

    Science.gov (United States)

    Borodin, A.; Mirvoda, S.; Porshnev, S.; Ponomareva, O.

    2018-01-01

    Concurrent operations on tree like data structures is a cornerstone of any database system. Concurrent operations intended for improving read\\write performance and usually implemented via some way of locking. Deadlock-free methods of concurrency control are known as tree locking protocols. These protocols provide basic operations(verbs) and algorithm (ways of operation invocations) for applying it to any tree-like data structure. These algorithms operate on data, managed by storage engine which are very different among RDBMS implementations. In this paper, we discuss tree locking protocol implementation for General inverted index (Gin) applied to multiversion concurrency control (MVCC) storage engine inside PostgreSQL RDBMS. After that we introduce improvements to locking protocol and provide usage statistics about evaluation of our improvement in very high load environment in one of the world’s largest IT company.

  7. Waiting for Art: The Experience of Real Time in Sculpture

    Directory of Open Access Journals (Sweden)

    Elizabeth Buhe

    2011-05-01

    Full Text Available Why and how does some contemporary art make us wait, and why does the beholder choose to stay? This study seeks to answer this question by exploring what happens to the viewer while waiting in front of a “time sculpture,” a term coined here to mean a three-dimensional artwork that is dynamic over a set period of time. Through an analysis of select works by artists Anish Kapoor, Amelia Whitelaw, Michael Sailstorfer, and Roman Signer, the article posits that while in front of these time sculptures, the viewer experiences an anxiety of waiting and temporal confusion that glues him to the spot. Ultimately, by drawing upon Henri Bergson’s concept of duration, the essay suggests that the viewership of time sculpture allows for a heightened state of perception. Normal 0 false false false EN-US X-NONE X-NONE

  8. Waiting Time Dynamics in Two-Dimensional Infrared Spectroscopy

    NARCIS (Netherlands)

    Jansen, Thomas L. C.; Knoester, Jasper

    We review recent work on the waiting time dynamics of coherent two-dimensional infrared (2DIR) spectroscopy. This dynamics can reveal chemical and physical processes that take place on the femto- and picosecond time scale, which is faster than the time scale that may be probed by, for example,

  9. Quality Improvement Cycles that Reduced Waiting Times at ...

    African Journals Online (AJOL)

    It was decided to undertake quality improvement (QI) cycles to analyse and improve the situation, using waiting time as a measure of improvement. Methods: A QI team was chosen to conduct two QI cycles. The allocated time for QI cycle 1 was from May to August 2006 and for QI cycle 2 from September to December 2006.

  10. Waiting Time Policies in the Health Care Sector. What Works?

    DEFF Research Database (Denmark)

    Christiansen, Terkel; Bech, Mickael

    2013-01-01

    times. In addition, a range of other measures may indirectly have affected waiting times, such as a general increase in spending on health care, the general practitioners’ role as gate-keepers, increased use of activity-based hospital reimbursement, increasing use of private heath insurance and private...

  11. Asymptotic analysis of SPTA-based algorithms for no-wait flow shop scheduling problem with release dates.

    Science.gov (United States)

    Ren, Tao; Zhang, Chuan; Lin, Lin; Guo, Meiting; Xie, Xionghang

    2014-01-01

    We address the scheduling problem for a no-wait flow shop to optimize total completion time with release dates. With the tool of asymptotic analysis, we prove that the objective values of two SPTA-based algorithms converge to the optimal value for sufficiently large-sized problems. To further enhance the performance of the SPTA-based algorithms, an improvement scheme based on local search is provided for moderate scale problems. New lower bound is presented for evaluating the asymptotic optimality of the algorithms. Numerical simulations demonstrate the effectiveness of the proposed algorithms.

  12. Asymptotic Analysis of SPTA-Based Algorithms for No-Wait Flow Shop Scheduling Problem with Release Dates

    Directory of Open Access Journals (Sweden)

    Tao Ren

    2014-01-01

    Full Text Available We address the scheduling problem for a no-wait flow shop to optimize total completion time with release dates. With the tool of asymptotic analysis, we prove that the objective values of two SPTA-based algorithms converge to the optimal value for sufficiently large-sized problems. To further enhance the performance of the SPTA-based algorithms, an improvement scheme based on local search is provided for moderate scale problems. New lower bound is presented for evaluating the asymptotic optimality of the algorithms. Numerical simulations demonstrate the effectiveness of the proposed algorithms.

  13. EVALUTION OF THE SINGLE INTERCITY FREIGHT TRANSPORTATION WAITING TIME

    Directory of Open Access Journals (Sweden)

    N. Ponomariova

    2015-07-01

    Full Text Available The example of vechicle operation on the pendulum intercity route during single freightages processing is considered. Two approaches to the definition of the single freightage waiting time by the carrier are proposed. These approaches allow to take into account the probability of the single freightage obtaining by the carrier during the different load level of the transport enterprise capacity.

  14. Potential impact of enhanced practice efficiency on endoscopy waiting times.

    LENUS (Irish Health Repository)

    Harewood, G C

    2009-06-01

    With the growing demand on endoscopy services, optimising practice efficiency has assumed increasing importance. Prior research has identified practice changes, which increase the efficiency in endoscopy. In this study, the potential impact of these practice changes on the current and projected future endoscopy waiting times at our institution was assessed.

  15. Waiting Time Increases Risk of Attrition in Gambling Disorder Treatment

    DEFF Research Database (Denmark)

    Linnet, Jakob; Pedersen, Anders Sune

    2014-01-01

    Attrition is a well known problem in psychotherapeutic treatment. Patients with addiction have high attrition rates, and it is therefore important to identify factors that can improve completion rates in addiction. Here, we investigated the influence of waiting time as a predictor of treatment...

  16. Incorporating waiting time in competitive location models: Formulations and heuristics

    OpenAIRE

    Silva, Francisco; Serra, Daniel

    2008-01-01

    In this paper we propose a metaheuristic to solve a new version of the Maximum Capture Problem. In the original MCP, market capture is obtained by lower traveling distances or lower traveling time, in this new version not only the traveling time but also the waiting time will affect the market share. This problem is hard to solve using standard optimization techniques. Metaheuristics are shown to offer accurate results within acceptable computing times.

  17. Minimizing makespan for a no-wait flowshop using genetic algorithm

    Indian Academy of Sciences (India)

    This paper explains minimization of makespan or total completion time .... lead to a natural reduction of the no-wait flow shop problem to the travelling sales- ... FCH can also be applied in real time scheduling and rescheduling for no-wait flow.

  18. The Social Relationship Based Adaptive Multi-Spray-and-Wait Routing Algorithm for Disruption Tolerant Network

    Directory of Open Access Journals (Sweden)

    Jianfeng Guan

    2017-01-01

    Full Text Available The existing spray-based routing algorithms in DTN cannot dynamically adjust the number of message copies based on actual conditions, which results in a waste of resource and a reduction of the message delivery rate. Besides, the existing spray-based routing protocols may result in blind spots or dead end problems due to the limitation of various given metrics. Therefore, this paper proposes a social relationship based adaptive multiple spray-and-wait routing algorithm (called SRAMSW which retransmits the message copies based on their residence times in the node via buffer management and selects forwarders based on the social relationship. By these means, the proposed algorithm can remove the plight of the message congestion in the buffer and improve the probability of replicas to reach their destinations. The simulation results under different scenarios show that the SRAMSW algorithm can improve the message delivery rate and reduce the messages’ dwell time in the cache and further improve the buffer effectively.

  19. Patient Satisfaction Is Associated With Time With Provider But Not Clinic Wait Time Among Orthopedic Patients.

    Science.gov (United States)

    Patterson, Brendan M; Eskildsen, Scott M; Clement, R Carter; Lin, Feng-Chang; Olcott, Christopher W; Del Gaizo, Daniel J; Tennant, Joshua N

    2017-01-01

    Clinic wait time is considered an important predictor of patient satisfaction. The goal of this study was to determine whether patient satisfaction among orthopedic patients is associated with clinic wait time and time with the provider. The authors prospectively enrolled 182 patients at their outpatient orthopedic clinic. Clinic wait time was defined as the time between patient check-in and being seen by the surgeon. Time spent with the provider was defined as the total time the patient spent in the examination room with the surgeon. The Consumer Assessment of Healthcare Providers and Systems survey was used to measure patient satisfaction. Factors associated with increased patient satisfaction included patient age and increased time with the surgeon (P=.024 and P=.037, respectively), but not clinic wait time (P=.625). Perceived wait time was subject to a high level of error, and most patients did not accurately report whether they had been waiting longer than 15 minutes to see a provider until they had waited at least 60 minutes (P=.007). If the results of the current study are generalizable, time with the surgeon is associated with patient satisfaction in orthopedic clinics, but wait time is not. Further, the study findings showed that patients in this setting did not have an accurate perception of actual wait time, with many patients underestimating the time they waited to see a provider. Thus, a potential strategy for improving patient satisfaction is to spend more time with each patient, even at the expense of increased wait time. [Orthopedics. 2017; 40(1):43-48.]. Copyright 2016, SLACK Incorporated.

  20. Reducing wait time in a hospital pharmacy to promote customer service.

    Science.gov (United States)

    Slowiak, Julie M; Huitema, Bradley E; Dickinson, Alyce M

    2008-01-01

    The purpose of this study was to compare the effects of 2 different interventions on wait times at a hospital outpatient pharmacy: (1) giving feedback to employees about customer satisfaction with wait times and (2) giving a combined intervention package that included giving more specific feedback about actual wait times and goal setting for wait time reduction in addition to the customer satisfaction feedback. The relationship between customer satisfaction ratings and wait times was examined to determine whether wait times affected customer service satisfaction. Participants were 10 employees (4 pharmacists and 6 technicians) of an outpatient pharmacy. Wait times and customer satisfaction ratings were collected for "waiting customers." An ABCBA' within-subjects design was used to assess the effects of the interventions on both wait time and customer satisfaction, where A was the baseline (no feedback and no goal setting); B was the customer satisfaction feedback; C was the customer satisfaction feedback, the wait time feedback, and the goal setting for wait time reduction; and A' was a follow-up condition that was similar to the original baseline condition. Wait times were reduced by approximately 20%, and there was concomitant increased shift in levels of customer satisfaction, as indicated by the correlation between these variables (r = -0.57 and P customer's wait time. Data from this study may provide useful preliminary benchmarking data for standard pharmacy wait times.

  1. An Elementary Derivation of Mean Wait Time in Polling Systems

    OpenAIRE

    Cady, Field

    2012-01-01

    Polling systems are a well-established subject in queueing theory. However, their formal treatments generally rely heavily on relatively sophisticated theoretical tools, such as moment generating functions and Laplace transforms, and solutions often require the solution of large systems of equations. We show that, if you are willing to only have the average waiting of a system time rather than higher moments, it can found through an elementary derivation based only on algebra and some well-kn...

  2. Burst wait time simulation of CALIBAN reactor at delayed super-critical state

    International Nuclear Information System (INIS)

    Humbert, P.; Authier, N.; Richard, B.; Grivot, P.; Casoli, P.

    2012-01-01

    In the past, the super prompt critical wait time probability distribution was measured on CALIBAN fast burst reactor [4]. Afterwards, these experiments were simulated with a very good agreement by solving the non-extinction probability equation [5]. Recently, the burst wait time probability distribution has been measured at CEA-Valduc on CALIBAN at different delayed super-critical states [6]. However, in the delayed super-critical case the non-extinction probability does not give access to the wait time distribution. In this case it is necessary to compute the time dependent evolution of the full neutron count number probability distribution. In this paper we present the point model deterministic method used to calculate the probability distribution of the wait time before a prescribed count level taking into account prompt neutrons and delayed neutron precursors. This method is based on the solution of the time dependent adjoint Kolmogorov master equations for the number of detections using the generating function methodology [8,9,10] and inverse discrete Fourier transforms. The obtained results are then compared to the measurements and Monte-Carlo calculations based on the algorithm presented in [7]. (authors)

  3. Burst wait time simulation of CALIBAN reactor at delayed super-critical state

    Energy Technology Data Exchange (ETDEWEB)

    Humbert, P. [Commissariat a l' Energie Atomique CEA, Centre de Bruyeres-le-Chatel, 91297 Arpajon (France); Authier, N.; Richard, B.; Grivot, P.; Casoli, P. [Commissariat a l' Energie Atomique CEA, Centre de Valduc, 21120 Is-sur-Tille (France)

    2012-07-01

    In the past, the super prompt critical wait time probability distribution was measured on CALIBAN fast burst reactor [4]. Afterwards, these experiments were simulated with a very good agreement by solving the non-extinction probability equation [5]. Recently, the burst wait time probability distribution has been measured at CEA-Valduc on CALIBAN at different delayed super-critical states [6]. However, in the delayed super-critical case the non-extinction probability does not give access to the wait time distribution. In this case it is necessary to compute the time dependent evolution of the full neutron count number probability distribution. In this paper we present the point model deterministic method used to calculate the probability distribution of the wait time before a prescribed count level taking into account prompt neutrons and delayed neutron precursors. This method is based on the solution of the time dependent adjoint Kolmogorov master equations for the number of detections using the generating function methodology [8,9,10] and inverse discrete Fourier transforms. The obtained results are then compared to the measurements and Monte-Carlo calculations based on the algorithm presented in [7]. (authors)

  4. Computation and evaluation of scheduled waiting time for railway networks

    DEFF Research Database (Denmark)

    Landex, Alex

    2010-01-01

    Timetables are affected by scheduled waiting time (SWT) that prolongs the travel times for trains and thereby passengers. SWT occurs when a train hinders another train to run with the wanted speed. The SWT affects both the trains and the passengers in the trains. The passengers may be further...... affected due to longer transfer times to other trains. SWT can be estimated analytically for a given timetable or by simulation of timetables and/or plans of operation. The simulation of SWT has the benefit that it is possible to examine the entire network. This makes it possible to improve the future...

  5. Evolutionary Hybrid Particle Swarm Optimization Algorithm for Solving NP-Hard No-Wait Flow Shop Scheduling Problems

    Directory of Open Access Journals (Sweden)

    Laxmi A. Bewoor

    2017-10-01

    Full Text Available The no-wait flow shop is a flowshop in which the scheduling of jobs is continuous and simultaneous through all machines without waiting for any consecutive machines. The scheduling of a no-wait flow shop requires finding an appropriate sequence of jobs for scheduling, which in turn reduces total processing time. The classical brute force method for finding the probabilities of scheduling for improving the utilization of resources may become trapped in local optima, and this problem can hence be observed as a typical NP-hard combinatorial optimization problem that requires finding a near optimal solution with heuristic and metaheuristic techniques. This paper proposes an effective hybrid Particle Swarm Optimization (PSO metaheuristic algorithm for solving no-wait flow shop scheduling problems with the objective of minimizing the total flow time of jobs. This Proposed Hybrid Particle Swarm Optimization (PHPSO algorithm presents a solution by the random key representation rule for converting the continuous position information values of particles to a discrete job permutation. The proposed algorithm initializes population efficiently with the Nawaz-Enscore-Ham (NEH heuristic technique and uses an evolutionary search guided by the mechanism of PSO, as well as simulated annealing based on a local neighborhood search to avoid getting stuck in local optima and to provide the appropriate balance of global exploration and local exploitation. Extensive computational experiments are carried out based on Taillard’s benchmark suite. Computational results and comparisons with existing metaheuristics show that the PHPSO algorithm outperforms the existing methods in terms of quality search and robustness for the problem considered. The improvement in solution quality is confirmed by statistical tests of significance.

  6. Canadian Consensus on Medically Acceptable Wait Times for Digestive Health Care

    Directory of Open Access Journals (Sweden)

    William G Paterson

    2006-01-01

    Full Text Available BACKGROUND: Delays in access to health care in Canada have been reported, but standardized systems to manage and monitor wait lists and wait times, and benchmarks for appropriate wait times, are lacking. The objective of the present consensus was to develop evidence- and expertise-based recommendations for medically appropriate maximal wait times for consultation and procedures by a digestive disease specialist.

  7. Pooled Open Blocks Shorten Wait Times for Nonelective Surgical Cases.

    Science.gov (United States)

    Zenteno, Ana C; Carnes, Tim; Levi, Retsef; Daily, Bethany J; Price, Devon; Moss, Susan C; Dunn, Peter F

    2015-07-01

    Assess the impact of the implementation of a data-driven scheduling strategy that aimed to improve the access to care of nonelective surgical patients at Massachusetts General Hospital (MGH). Between July 2009 and June 2010, MGH experienced increasing throughput challenges in its perioperative environment: approximately 30% of the nonelective patients were waiting more than the prescribed amount of time to get to surgery, hampering access to care and aggravating the lack of inpatient beds. This work describes the design and implementation of an "open block" strategy: operating room (OR) blocks were reserved for nonelective patients during regular working hours (prime time) and their management centralized. Discrete event simulation showed that 5 rooms would decrease the percentage of delayed patients from 30% to 2%, assuming that OR availability was the only reason for preoperative delay. Implementation began in January 2012. We compare metrics for June through December of 2012 against the same months of 2011. The average preoperative wait time of all nonelective surgical patients decreased by 25.5% (P reason for delay. Rigorous metrics were developed to evaluate its performance. Strong managerial leadership was crucial to enact the new practices and turn them into organizational change.

  8. Determining prescription durations based on the parametric waiting time distribution

    DEFF Research Database (Denmark)

    Støvring, Henrik; Pottegård, Anton; Hallas, Jesper

    2016-01-01

    two-component mixture model for the waiting time distribution (WTD). The distribution component for prevalent users estimates the forward recurrence density (FRD), which is related to the distribution of time between subsequent prescription redemptions, the inter-arrival density (IAD), for users...... in continued treatment. We exploited this to estimate percentiles of the IAD by inversion of the estimated FRD and defined the duration of a prescription as the time within which 80% of current users will have presented themselves again. Statistical properties were examined in simulation studies......-Normal). When the IAD consisted of a mixture of two Log-Normal distributions, but was analyzed with a single Log-Normal distribution, relative bias did not exceed 9%. Using a Log-Normal FRD, we estimated prescription durations of 117, 91, 137, and 118 days for NSAIDs, warfarin, bendroflumethiazide...

  9. Reducing pharmacy wait time to promote customer service: a follow-up study.

    Science.gov (United States)

    Slowiak, Julie M; Huitema, Bradley E

    2015-01-01

    The present study had 3 objectives: (1) to evaluate the effects of 2 different interventions (feedback regarding customer satisfaction with wait time and combined feedback and goal setting) on wait time in a hospital outpatient pharmacy; (2) to assess the extent to which the previously applied interventions maintained their effects; and (3) to evaluate the differences between the effects of the original study and those of the present follow-up study. Participants were 10 employees (4 pharmacists and 6 technicians) of an outpatient pharmacy. Wait times and customer satisfaction ratings were collected for "waiting customers." An ABCB within-subjects design was used to assess the effects of the interventions on both wait time and customer satisfaction, where A was the baseline (no feedback and no goal setting); B was the customer satisfaction feedback; and C was the customer satisfaction feedback, the wait time feedback, and the goal setting for wait time reduction. Wait time decreased after baseline when the combined intervention was introduced, and wait time increased with the reintroduction of satisfaction feedback (alone). The results of the replication study confirm the pattern of the results of the original study and demonstrate high sensitivity of levels of customer satisfaction with wait time. The most impressive result of the replication is the nearly 2-year maintenance of lower wait time between the end of the original study and the beginning (baseline) of the replication.

  10. The British Columbia Nephrologists' Access Study (BCNAS) - a prospective, health services interventional study to develop waiting time benchmarks and reduce wait times for out-patient nephrology consultations.

    Science.gov (United States)

    Schachter, Michael E; Romann, Alexandra; Djurdev, Ognjenka; Levin, Adeera; Beaulieu, Monica

    2013-08-29

    Early referral and management of high-risk chronic kidney disease may prevent or delay the need for dialysis. Automatic eGFR reporting has increased demand for out-patient nephrology consultations and in some cases, prolonged queues. In Canada, a national task force suggested the development of waiting time targets, which has not been done for nephrology. We sought to describe waiting time for outpatient nephrology consultations in British Columbia (BC). Data collection occurred in 2 phases: 1) Baseline Description (Jan 18-28, 2010) and 2) Post Waiting Time Benchmark-Introduction (Jan 16-27, 2012). Waiting time was defined as the interval from receipt of referral letters to assessment. Using a modified Delphi process, Nephrologists and Family Physicians (FP) developed waiting time targets for commonly referred conditions through meetings and surveys. Rules were developed to weigh-in nephrologists', FPs', and patients' perspectives in order to generate waiting time benchmarks. Targets consider comorbidities, eGFR, BP and albuminuria. Referred conditions were assigned a priority score between 1-4. BC nephrologists were encouraged to centrally triage referrals to see the first available nephrologist. Waiting time benchmarks were simultaneously introduced to guide patient scheduling. A post-intervention waiting time evaluation was then repeated. In 2010 and 2012, 43/52 (83%) and 46/57 (81%) of BC nephrologists participated. Waiting time decreased from 98(IQR44,157) to 64(IQR21,120) days from 2010 to 2012 (p = management associated with improved access to nephrologists in BC. Improvements in waiting time was most marked for the highest priority patients, which suggests that benchmarks had an influence on triaging behavior. Further research is needed to determine whether this effect is sustainable.

  11. Success Run Waiting Times and Fuss-Catalan Numbers

    Directory of Open Access Journals (Sweden)

    S. J. Dilworth

    2015-01-01

    Full Text Available We present power series expressions for all the roots of the auxiliary equation of the recurrence relation for the distribution of the waiting time for the first run of k consecutive successes in a sequence of independent Bernoulli trials, that is, the geometric distribution of order k. We show that the series coefficients are Fuss-Catalan numbers and write the roots in terms of the generating function of the Fuss-Catalan numbers. Our main result is a new exact expression for the distribution, which is more concise than previously published formulas. Our work extends the analysis by Feller, who gave asymptotic results. We obtain quantitative improvements of the error estimates obtained by Feller.

  12. Waiting Time Distributions for Pattern Occurrence in a Constrained Sequence

    Directory of Open Access Journals (Sweden)

    Valeri Stefanov

    2007-01-01

    Full Text Available A binary sequence of zeros and ones is called a (d,k-sequence if it does not contain runs of zeros of length either less than d or greater than k, where d and k are arbitrary, but fixed, non-negative integers and d < k. Such sequences find an abundance of applications in communications, in particular for magnetic and optical recording. Occasionally, one requires that (d,k-sequences do not contain a specific pattern w. Therefore, distribution results concerning pattern occurrence in (d,k-sequences are of interest. In this paper we study the distribution of the waiting time until the r th occurrence of a pattern w in a random (d,k-sequence generated by a Markov source. Numerical examples are also provided.

  13. Associations Between Waiting Times, Service Times, and Patient Satisfaction in an Endocrinology Outpatient Department: A Time Study and Questionnaire Survey.

    Science.gov (United States)

    Xie, Zhenzhen; Or, Calvin

    2017-01-01

    The issue of long patient waits has attracted increasing public attention due to the negative effects of waiting on patients' satisfaction with health care. The present study examined the associations between actual waiting time, perceived acceptability of waiting time, actual service time, perceived acceptability of service time, actual visit duration, and the level of patient satisfaction with care. We conducted a cross-sectional time study and questionnaire survey of endocrinology outpatients visiting a major teaching hospital in China. Our results show that actual waiting time was negatively associated with patient satisfaction regarding several aspects of the care they received. Also, patients who were less satisfied with the sociocultural atmosphere and the identity-oriented approach to their care tended to perceive the amounts of time they spent waiting and receiving care as less acceptable. It is not always possible to prevent dissatisfaction with waiting, or to actually reduce waiting times by increasing resources such as increased staffing. However, several improvements in care services can be considered. Our suggestions include providing clearer, more transparent information to keep patients informed about the health care services that they may receive, and the health care professionals who are responsible for those services. We also suggest that care providers are encouraged to continue to show empathy and respect for patients, that patients are provided with private areas where they can talk with health professionals and no one can overhear, and that hospital staff treat the family members or friends who accompany patients in a courteous and friendly way.

  14. The effect of waiting times on demand and supply for elective surgery: Evidence from Italy.

    Science.gov (United States)

    Riganti, Andrea; Siciliani, Luigi; Fiorio, Carlo V

    2017-09-01

    Waiting times are a major policy concern in publicly funded health systems across OECD countries. Economists have argued that, in the presence of excess demand, waiting times act as nonmonetary prices to bring demand for and supply of health care in equilibrium. Using administrative data disaggregated by region and surgical procedure over 2010-2014 in Italy, we estimate demand and supply elasticities with respect to waiting times. We employ linear regression models with first differences and instrumental variables to deal with endogeneity of waiting times. We find that demand is inelastic to waiting times while supply is more elastic. Estimates of demand elasticity are between -0.15 to -0.24. Our results have implications on the effectiveness of policies aimed at increasing supply and their ability to reduce waiting times. Copyright © 2017 John Wiley & Sons, Ltd.

  15. Waiting time disparities in breast cancer diagnosis and treatment: a population-based study in France.

    Science.gov (United States)

    Molinié, F; Leux, C; Delafosse, P; Ayrault-Piault, S; Arveux, P; Woronoff, A S; Guizard, A V; Velten, M; Ganry, O; Bara, S; Daubisse-Marliac, L; Tretarre, B

    2013-10-01

    Waiting times are key indicators of a health's system performance, but are not routinely available in France. We studied waiting times for diagnosis and treatment according to patients' characteristics, tumours' characteristics and medical management options in a sample of 1494 breast cancers recorded in population-based registries. The median waiting time from the first imaging detection to the treatment initiation was 34 days. Older age, co-morbidity, smaller size of tumour, detection by organised screening, biopsy, increasing number of specimens removed, multidisciplinary consulting meetings and surgery as initial treatment were related to increased waiting times in multivariate models. Many of these factors were related to good practices guidelines. However, the strong influence of organised screening programme and the disparity of waiting times according to geographical areas were of concern. Better scheduling of diagnostic tests and treatment propositions should improve waiting times in the management of breast cancer in France. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Relative entropy and waiting time for continuous-time Markov processes

    NARCIS (Netherlands)

    Chazottes, J.R.; Giardinà, C.; Redig, F.H.J.

    2006-01-01

    For discrete-time stochastic processes, there is a close connection between return (resp. waiting) times and entropy (resp. relative entropy). Such a connection cannot be straightforwardly extended to the continuous-time setting. Contrarily to the discrete-time case one needs a reference measure on

  17. Should I stay or should I go? Hospital emergency department waiting times and demand.

    Science.gov (United States)

    Sivey, Peter

    2018-03-01

    In the absence of the price mechanism, hospital emergency departments rely on waiting times, alongside prioritisation mechanisms, to restrain demand and clear the market. This paper estimates by how much the number of treatments demanded is reduced by a higher waiting time. I use variation in waiting times for low-urgency patients caused by rare and resource-intensive high-urgency patients to estimate the relationship. I find that when waiting times are higher, more low-urgency patients are deterred from treatment and leave the hospital during the waiting period without being treated. The waiting time elasticity of demand for low-urgency patients is approximately -0.25 and is highest for the lowest-urgency patients. Copyright © 2017 John Wiley & Sons, Ltd.

  18. Norwegian Priority Setting in Practice – an Analysis of Waiting Time Patterns Across Medical Disciplines

    Directory of Open Access Journals (Sweden)

    Jurgita Januleviciute Gangstøe

    2016-06-01

    Full Text Available Background: Different strategies for addressing the challenge of prioritizing elective patients efficiently and fairly have been introduced in Norway. In the time period studied, there were three possible outcomes for elective patients that had been through the process of priority setting: (i high priority with assigned individual maximum waiting time; (ii low priority without a maximum waiting time; and (iii refusal (not in need for specialized services. We study variation in priority status and waiting time of the first two groups across different medical disciplines. Methods: Data was extracted from the Norwegian Patient Register (NPR and contains information on elective referrals to 41 hospitals in the Western Norway Regional Health Authority in 2010. The hospital practice across different specialties was measured by patient priority status and waiting times. The distributions of assigned maximum waiting times and the actual ones were analyzed using standard Kernel density estimation. The perspective of the planning process was studied by measuring the time interval between the actual start of healthcare and the maximum waiting time. Results: Considerable variation was found across medical specialties concerning proportion of priority patients and their maximum waiting times. The degree of differentiation in terms of maximum waiting times also varied by medical discipline. We found that the actual waiting time was very close to the assigned maximum waiting time. Furthermore, there was no clear correspondence between the actual waiting time for patients and their priority status. Conclusion: Variations across medical disciplines are often interpreted as differences in clinical judgment and capacity. Alternatively they primarily reflect differences in patient characteristics, patient case-mix, as well as capacity. One hypothesis for further research is that the introduction of maximum waiting times may have contributed to push the actual

  19. Models of emergency departments for reducing patient waiting times.

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    Marek Laskowski

    Full Text Available In this paper, we apply both agent-based models and queuing models to investigate patient access and patient flow through emergency departments. The objective of this work is to gain insights into the comparative contributions and limitations of these complementary techniques, in their ability to contribute empirical input into healthcare policy and practice guidelines. The models were developed independently, with a view to compare their suitability to emergency department simulation. The current models implement relatively simple general scenarios, and rely on a combination of simulated and real data to simulate patient flow in a single emergency department or in multiple interacting emergency departments. In addition, several concepts from telecommunications engineering are translated into this modeling context. The framework of multiple-priority queue systems and the genetic programming paradigm of evolutionary machine learning are applied as a means of forecasting patient wait times and as a means of evolving healthcare policy, respectively. The models' utility lies in their ability to provide qualitative insights into the relative sensitivities and impacts of model input parameters, to illuminate scenarios worthy of more complex investigation, and to iteratively validate the models as they continue to be refined and extended. The paper discusses future efforts to refine, extend, and validate the models with more data and real data relative to physical (spatial-topographical and social inputs (staffing, patient care models, etc.. Real data obtained through proximity location and tracking system technologies is one example discussed.

  20. The acceptability of waiting times for elective general surgery and the appropriateness of prioritising patients

    Directory of Open Access Journals (Sweden)

    Knol Dirk L

    2007-02-01

    Full Text Available Abstract Background Problematic waiting lists in public health care threaten the equity and timeliness of care provision in several countries. This study assesses different stakeholders' views on the acceptability of waiting lists in health care, their preferences for priority care of patients, and their judgements on acceptable waiting times for surgical patients. Methods A questionnaire survey was conducted among 257 former patients (82 with varicose veins, 86 with inguinal hernia, and 89 with gallstones, 101 surgeons, 95 occupational physicians, and 65 GPs. Judgements on acceptable waiting times were assessed using vignettes of patients with varicose veins, inguinal hernia, and gallstones. Results Participants endorsed the prioritisation of patients based on clinical need, but not on ability to benefit. The groups had significantly different opinions (p Acceptable waiting times ranged between 2 and 25 weeks depending on the type of disorder (p Conclusion The explicit prioritisation of patients seems an accepted means for reducing the overall burden from waiting lists. The disagreement about appropriate prioritisation criteria and the need for uniformity, however, raises concern about equity when implementing prioritisation in daily practice. Single factor waiting time thresholds seem insufficient for securing timely care provision in the presence of long waiting lists as they do not account for the different consequences of waiting between patients.

  1. Spatial structure increases the waiting time for cancer

    Science.gov (United States)

    Martens, Erik A.; Kostadinov, Rumen; Maley, Carlo C.; Hallatschek, Oskar

    2011-11-01

    Cancer results from a sequence of genetic and epigenetic changes that lead to a variety of abnormal phenotypes including increased proliferation and survival of somatic cells and thus to a selective advantage of pre-cancerous cells. The notion of cancer progression as an evolutionary process has been attracting increasing interest in recent years. A great deal of effort has been made to better understand and predict the progression to cancer using mathematical models; these mostly consider the evolution of a well-mixed cell population, even though pre-cancerous cells often evolve in highly structured epithelial tissues. In this study, we propose a novel model of cancer progression that considers a spatially structured cell population where clones expand via adaptive waves. This model is used to assess two different paradigms of asexual evolution that have been suggested to delineate the process of cancer progression. The standard scenario of periodic selection assumes that driver mutations are accumulated strictly sequentially over time. However, when the mutation supply is sufficiently high, clones may arise simultaneously on distinct genetic backgrounds, and clonal adaptation waves interfere with each other. We find that in the presence of clonal interference, spatial structure increases the waiting time for cancer, leads to a patchwork structure of non-uniformly sized clones and decreases the survival probability of virtually neutral (passenger) mutations, and that genetic distance begins to increase over a characteristic length scale Lc. These characteristic features of clonal interference may help us to predict the onset of cancers with pronounced spatial structure and to interpret spatially sampled genetic data obtained from biopsies. Our estimates suggest that clonal interference likely occurs in the progression of colon cancer and possibly other cancers where spatial structure matters.

  2. Waiting Endurance Time Estimation of Electric Two-Wheelers at Signalized Intersections

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    Mei Huan

    2014-01-01

    Full Text Available The paper proposed a model for estimating waiting endurance times of electric two-wheelers at signalized intersections using survival analysis method. Waiting duration times were collected by video cameras and they were assigned as censored and uncensored data to distinguish between normal crossing and red-light running behavior. A Cox proportional hazard model was introduced, and variables revealing personal characteristics and traffic conditions were defined as covariates to describe the effects of internal and external factors. Empirical results show that riders do not want to wait too long to cross intersections. As signal waiting time increases, electric two-wheelers get impatient and violate the traffic signal. There are 12.8% of electric two-wheelers with negligible wait time. 25.0% of electric two-wheelers are generally nonrisk takers who can obey the traffic rules after waiting for 100 seconds. Half of electric two-wheelers cannot endure 49.0 seconds or longer at red-light phase. Red phase time, motor vehicle volume, and conformity behavior have important effects on riders’ waiting times. Waiting endurance times would decrease with the longer red-phase time, the lower traffic volume, or the bigger number of other riders who run against the red light. The proposed model may be applicable in the design, management and control of signalized intersections in other developing cities.

  3. Waiting endurance time estimation of electric two-wheelers at signalized intersections.

    Science.gov (United States)

    Huan, Mei; Yang, Xiao-bao

    2014-01-01

    The paper proposed a model for estimating waiting endurance times of electric two-wheelers at signalized intersections using survival analysis method. Waiting duration times were collected by video cameras and they were assigned as censored and uncensored data to distinguish between normal crossing and red-light running behavior. A Cox proportional hazard model was introduced, and variables revealing personal characteristics and traffic conditions were defined as covariates to describe the effects of internal and external factors. Empirical results show that riders do not want to wait too long to cross intersections. As signal waiting time increases, electric two-wheelers get impatient and violate the traffic signal. There are 12.8% of electric two-wheelers with negligible wait time. 25.0% of electric two-wheelers are generally nonrisk takers who can obey the traffic rules after waiting for 100 seconds. Half of electric two-wheelers cannot endure 49.0 seconds or longer at red-light phase. Red phase time, motor vehicle volume, and conformity behavior have important effects on riders' waiting times. Waiting endurance times would decrease with the longer red-phase time, the lower traffic volume, or the bigger number of other riders who run against the red light. The proposed model may be applicable in the design, management and control of signalized intersections in other developing cities.

  4. Waiting Time from Diagnosis to Treatment has no Impact on Survival in Patients with Esophageal Cancer

    NARCIS (Netherlands)

    Visser, E.; Leeftink, Anne Greetje; van Rossum, P.S.N.; Siesling, Sabine; van Hillegersberg, R.; Ruurda, J.P.

    2016-01-01

    Background Waiting time from diagnosis to treatment has emerged as an important quality indicator in cancer care. This study was designed to determine the impact of waiting time on long-term outcome of patients with esophageal cancer who are treated with neoadjuvant therapy followed by surgery or

  5. Client waiting time in an urban primary health care centre in Lagos ...

    African Journals Online (AJOL)

    Background: Primary Health Care is the usual entry point into the health system and has the potential to touch the lives of most people. However one of the reasons for poor uptake of health services at primary health care facilities in Nigeria is long waiting time. This study was carried out to assess client waiting time and ...

  6. Effects of Wait Time When Communicating with Children Who Have Sensory and Additional Disabilities

    Science.gov (United States)

    Johnson, Nicole; Parker, Amy T.

    2013-01-01

    Introduction: This study utilized wait-time procedures to determine if they are effective in helping children with deafblindness or multiple disabilities that include a visual impairment communicate in their home. Methods: A single subject with an alternating treatment design was used for the study. Zero- to one-second wait time was utilized…

  7. Determinants of Patient Waiting Time in the General Outpatient ...

    African Journals Online (AJOL)

    obtaining services and keeping patients waiting unnecessarily can be a cause of stress for both .... Simple random sampling was done for the first two patients to get the starting ... record clerks (12% [9/76]), and jumping of queue by patients.

  8. Research on the waiting time of passengers and escalator energy consumption at the railway station

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Wei-wu; Liu, Xiao-yan; Li, Liqing; Shi, Xiangnan; Zhou, Chenn Q. [School of Energy Science and Engineering, Central South University, Changsha 410083 (China)

    2009-12-15

    Based on the Little Formula and the classical queuing model of multi-channel M vertical stroke D vertical stroke n, the relation of the average queue length, the maximum waiting time and the escalator service intensity were identified and the waiting time simulation model was established. With the passenger delivery data at A railway station in China and the probability distribution model of waiting time, a detailed analysis was made on the escalator allocation, power and energy consumption on holidays, ordinary working days and the largest-passengers-volume days; meanwhile, the fixed and variable energy consumption were compared and studied when the waiting time are 5, 10 and 30 s. The result shows that the waiting time settings affect the allocation and the energy consumption of the escalators and the fixed energy consumption takes 70%. (author)

  9. [Waiting time for the first colposcopic examination in women with abnormal Papanicolaou test].

    Science.gov (United States)

    Nascimento, Maria Isabel do; Rabelo, Irene Machado Moraes Alvarenga; Cardoso, Fabrício Seabra Polidoro; Musse, Ricardo Neif Vieira

    2015-08-01

    To evaluate the waiting times before obtaining the first colposcopic examination for women with abnormal Papanicolaou smears. Retrospective cohort study conducted on patients who required a colposcopic examination to clarify an abnormal pap test, between 2002 January and 2008 August, in a metropolitan region of Brazil. The waiting times were defined as: Total Waiting Time (interval between the date of the pap test result and the date of the first colposcopic examination); Partial A Waiting Time (interval between the date of the pap test result and the date of referral); Partial B Waiting Time (interval between the date of referral and the date of the first colposcopic examination). Means, medians, relative and absolute frequencies were calculated. The Kruskal-Wallis test and Pearson's chi-square test were used to determine statistical significance. A total of 1,544 women with mean of age of 34 years (SD=12.6 years) were analyzed. Most of them had access to colposcopic examination within 30 days (65.8%) or 60 days (92.8%) from referral. Mean Total Waiting Time, Partial A Waiting Time, and Partial B Waiting Time were 94.5 days (SD=96.8 days), 67.8 days (SD=95.3 days) and 29.2 days (SD=35.1 days), respectively. A large part of the women studied had access to colposcopic examination within 60 days after referral, but Total waiting time was long. Measures to reduce the waiting time for obtaining the first colposcopic examination can help to improve the quality of care in the context of cervical cancer control in the region, and ought to be addressed at the phase between the date of the pap test results and the date of referral to the teaching hospital.

  10. Space, place and (waiting) time: reflections on health policy and politics.

    Science.gov (United States)

    Sheard, Sally

    2018-02-19

    Health systems have repeatedly addressed concerns about efficiency and equity by employing trans-national comparisons to draw out the strengths and weaknesses of specific policy initiatives. This paper demonstrates the potential for explicit historical analysis of waiting times for hospital treatment to add value to spatial comparative methodologies. Waiting times and the size of the lists of waiting patients have become key operational indicators. In the United Kingdom, as National Health Service (NHS) financial pressures intensified from the 1970s, waiting times have become a topic for regular public and political debate. Various explanations for waiting times include the following: hospital consultants manipulate NHS waiting lists to maintain their private practice; there is under-investment in the NHS; and available (and adequate) resources are being used inefficiently. Other countries have also experienced ongoing tensions between the public and private delivery of universal health care in which national and trans-national comparisons of waiting times have been regularly used. The paper discusses the development of key UK policies, and provides a limited Canadian comparative perspective, to explore wider issues, including whether 'waiting crises' were consciously used by policymakers, especially those brought into government to implement new economic and managerial strategies, to diminish the autonomy and authority of the medical professional in the hospital environment.

  11. Prediction problem for target events based on the inter-event waiting time

    Science.gov (United States)

    Shapoval, A.

    2010-11-01

    In this paper we address the problem of forecasting the target events of a time series given the distribution ξ of time gaps between target events. Strong earthquakes and stock market crashes are the two types of such events that we are focusing on. In the series of earthquakes, as McCann et al. show [W.R. Mc Cann, S.P. Nishenko, L.R. Sykes, J. Krause, Seismic gaps and plate tectonics: seismic potential for major boundaries, Pure and Applied Geophysics 117 (1979) 1082-1147], there are well-defined gaps (called seismic gaps) between strong earthquakes. On the other hand, usually there are no regular gaps in the series of stock market crashes [M. Raberto, E. Scalas, F. Mainardi, Waiting-times and returns in high-frequency financial data: an empirical study, Physica A 314 (2002) 749-755]. For the case of seismic gaps, we analytically derive an upper bound of prediction efficiency given the coefficient of variation of the distribution ξ. For the case of stock market crashes, we develop an algorithm that predicts the next crash within a certain time interval after the previous one. We show that this algorithm outperforms random prediction. The efficiency of our algorithm sets up a lower bound of efficiency for effective prediction of stock market crashes.

  12. Waiting times for prostate cancer diagnosis in KwaZulu-Natal, South ...

    African Journals Online (AJOL)

    prostate cancer (an elevated prostate-specific antigen level or abnormal findings on digital rectal examination) wait to have a prostate biopsy. Objectives. To improve the overall efficiency of the prostate biopsy service offered at St Aidan's Regional Hospital, Durban, SA, by quantifying the burden of disease and waiting times ...

  13. Reading of Waiting, Time and Social Change in S. N. A. Agoro's ...

    African Journals Online (AJOL)

    It is against this backdrop that we attempt to explore the depiction and treatment of waiting, time and social change in the dramatic universe of existentialism created by some playwrights who have not been given scholarly attention. The study shall therefore undertake a dialectical consideration of the concept of waiting and ...

  14. A RFID-based JIT Application for Least Waiting Time for Dynamic Smart Diet Customers

    Directory of Open Access Journals (Sweden)

    Chen Long-Fei

    2017-01-01

    Full Text Available Waiting in queue is part of everyone’s life. A day may include several different waiting in queue. Waiting in line is always a bit of phenomena for a prosperous restaurant at dinner time. How to manage the queues and keep their feet into customers is the operating challenge facing everyone manager. In addition, rising energy costs and growing demand for protection of the environment call for a shorter waiting queue. Thus, we devise a dynamic smart diet App manager to reduce customer waiting time through radio frequency identification (RFID and just in time (JIT principle to reduce inventory of restaurant food materials, thereby increasing customer satisfaction and loyalty, and improving revenue and social responsibility.

  15. General practice cooperatives: long waiting times for home visits due to long distances?

    Science.gov (United States)

    Giesen, Paul; van Lin, Nieke; Mokkink, Henk; van den Bosch, Wil; Grol, Richard

    2007-02-12

    The introduction of large-scale out-of-hours GP cooperatives has led to questions about increased distances between the GP cooperatives and the homes of patients and the increasing waiting times for home visits in urgent cases. We studied the relationship between the patient's waiting time for a home visit and the distance to the GP cooperative. Further, we investigated if other factors (traffic intensity, home visit intensity, time of day, and degree of urgency) influenced waiting times. Cross-sectional study at four GP cooperatives. We used variance analysis to calculate waiting times for various categories of traffic intensity, home visit intensity, time of day, and degree of urgency. We used multiple logistic regression analysis to calculate to what degree these factors affected the ability to meet targets in urgent cases. The average waiting time for 5827 consultations was 30.5 min. Traffic intensity, home visit intensity, time of day and urgency of the complaint all seemed to affect waiting times significantly. A total of 88.7% of all patients were seen within 1 hour. In the case of life-threatening complaints (U1), 68.8% of the patients were seen within 15 min, and 95.6% of those with acute complaints (U2) were seen within 1 hour. For patients with life-threatening complaints (U1) the percentage of visits that met the time target of 15 minutes decreased from 86.5% (less than 2.5 km) to 16.7% (equals or more than 20 km). Although home visits waiting times increase with increasing distance from the GP cooperative, it appears that traffic intensity, home visit intensity, and urgency also influence waiting times. For patients with life-threatening complaints waiting times increase sharply with the distance.

  16. Survey of Access to GastroEnterology in Canada: The SAGE wait times program

    Science.gov (United States)

    Leddin, Desmond; Bridges, Ronald J; Morgan, David G; Fallone, Carlo; Render, Craig; Plourde, Victor; Gray, Jim; Switzer, Connie; McHattie, Jim; Singh, Harminder; Walli, Eric; Murray, Iain; Nestel, Anthony; Sinclair, Paul; Chen, Ying; Irvine, E Jan

    2010-01-01

    BACKGROUND: Assessment of current wait times for specialist health services in Canada is a key method that can assist government and health care providers to plan wisely for future health needs. These data are not readily available. A method to capture wait time data at the time of consultation or procedure has been developed, which should be applicable to other specialist groups and also allows for assessment of wait time trends over intervals of years. METHODS: In November 2008, gastroenterologists across Canada were asked to complete a questionnaire (online or by fax) that included personal demographics and data from one week on at least five consecutive new consultations and five consecutive procedure patients who had not previously undergone a procedure for the same indication. Wait times were collected for 18 primary indications and results were then compared with similar survey data collected in 2005. RESULTS: The longest wait times observed were for screening colonoscopy (201 days) and surveillance of previous colon cancer or polyps (272 days). The shortest wait times were for cancer-likely based on imaging or physical examination (82 days), severe or rapidly progressing dysphagia or odynophagia (83 days), documented iron-deficiency anemia (90 days) and dyspepsia with alarm symptoms (99 days). Compared with 2005 data, total wait times in 2008 were lengthened overall (127 days versus 155 days; Pgastroenterology services continue to exceed consensus conference recommended targets and have significantly worsened since 2005. PMID:20186352

  17. Adjusting patients streaming initiated by a wait time threshold in emergency department for minimizing opportunity cost.

    Science.gov (United States)

    Kim, Byungjoon B J; Delbridge, Theodore R; Kendrick, Dawn B

    2017-07-10

    Purpose Two different systems for streaming patients were considered to improve efficiency measures such as waiting times (WTs) and length of stay (LOS) for a current emergency department (ED). A typical fast track area (FTA) and a fast track with a wait time threshold (FTW) were designed and compared effectiveness measures from the perspective of total opportunity cost of all patients' WTs in the ED. The paper aims to discuss these issues. Design/methodology/approach This retrospective case study used computerized ED patient arrival to discharge time logs (between July 1, 2009 and June 30, 2010) to build computer simulation models for the FTA and fast track with wait time threshold systems. Various wait time thresholds were applied to stream different acuity-level patients. National average wait time for each acuity level was considered as a threshold to stream patients. Findings The fast track with a wait time threshold (FTW) showed a statistically significant shorter total wait time than the current system or a typical FTA system. The patient streaming management would improve the service quality of the ED as well as patients' opportunity costs by reducing the total LOS in the ED. Research limitations/implications The results of this study were based on computer simulation models with some assumptions such as no transfer times between processes, an arrival distribution of patients, and no deviation of flow pattern. Practical implications When the streaming of patient flow can be managed based on the wait time before being seen by a physician, it is possible for patients to see a physician within a tolerable wait time, which would result in less crowded in the ED. Originality/value A new streaming scheme of patients' flow may improve the performance of fast track system.

  18. Public views on a wait time management initiative: a matter of communication.

    Science.gov (United States)

    Bruni, Rebecca A; Laupacis, Andreas; Levinson, Wendy; Martin, Douglas K

    2010-08-05

    Many countries have tried to reduce waiting times for health care through formal wait time reduction strategies. Our paper describes views of members of the public about a wait time management initiative--the Ontario Wait Time Strategy (OWTS) (Canada). Scholars and governmental reports have advocated for increased public involvement in wait time management. We provide empirically derived recommendations for public engagement in a wait time management initiative. Two qualitative studies: 1) an analysis of all emails sent by the public to the (OWTS) email address; and 2) in-depth interviews with members of the Ontario public. Email correspondents and interview participants supported the intent of the OWTS. However they wanted more information about the Strategy and its actions. Interview participants did not feel they were sufficiently made aware of the Strategy and email correspondents requested additional information beyond what was offered on the Strategy's website. Moreover, the email correspondents believed that some of the information that was provided on the Strategy's website and through the media was inaccurate, misleading, and even dishonest. Interview participants strongly supported public involvement in the OWTS priority setting. Findings suggest the public wanted increased communication from and with the OWTS. Effective communication can facilitate successful public engagement, and in turn fair and legitimate priority setting. Based on the study's findings we developed concrete recommendations for improving public involvement in wait time management.

  19. Public views on a wait time management initiative: a matter of communication

    Directory of Open Access Journals (Sweden)

    Laupacis Andreas

    2010-08-01

    Full Text Available Abstract Background Many countries have tried to reduce waiting times for health care through formal wait time reduction strategies. Our paper describes views of members of the public about a wait time management initiative - the Ontario Wait Time Strategy (OWTS (Canada. Scholars and governmental reports have advocated for increased public involvement in wait time management. We provide empirically derived recommendations for public engagement in a wait time management initiative. Methods Two qualitative studies: 1 an analysis of all emails sent by the public to the (OWTS email address; and 2 in-depth interviews with members of the Ontario public. Results Email correspondents and interview participants supported the intent of the OWTS. However they wanted more information about the Strategy and its actions. Interview participants did not feel they were sufficiently made aware of the Strategy and email correspondents requested additional information beyond what was offered on the Strategy's website. Moreover, the email correspondents believed that some of the information that was provided on the Strategy's website and through the media was inaccurate, misleading, and even dishonest. Interview participants strongly supported public involvement in the OWTS priority setting. Conclusions Findings suggest the public wanted increased communication from and with the OWTS. Effective communication can facilitate successful public engagement, and in turn fair and legitimate priority setting. Based on the study's findings we developed concrete recommendations for improving public involvement in wait time management.

  20. Improving Wait Times to Care for Individuals with Multimorbidities and Complex Conditions Using Value Stream Mapping

    Directory of Open Access Journals (Sweden)

    Tara Sampalli

    2015-07-01

    Full Text Available Background Recognizing the significant impact of wait times for care for individuals with complex chronic conditions, we applied a LEAN methodology, namely – an adaptation of Value Stream Mapping (VSM to meet the needs of people with multiple chronic conditions and to improve wait times without additional resources or funding. Methods Over an 18-month time period, staff applied a patient-centric approach that included LEAN methodology of VSM to improve wait times to care. Our framework of evaluation was grounded in the needs and perspectives of patients and individuals waiting to receive care. Patient centric views were obtained through surveys such as Patient Assessment of Chronic Illness Care (PACIC and process engineering based questions. In addition, LEAN methodology, VSM was added to identify non-value added processes contributing to wait times. Results The care team successfully reduced wait times to 2 months in 2014 with no wait times for care anticipated in 2015. Increased patient engagement and satisfaction are also outcomes of this innovative initiative. In addition, successful transformations and implementation have resulted in resource efficiencies without increase in costs. Patients have shown significant improvements in functional health following Integrated Chronic Care Service (ICCS intervention. The methodology will be applied to other chronic disease management areas in Capital Health and the province. Conclusion Wait times to care in the management of multimoribidities and other complex conditions can add a significant burden not only on the affected individuals but also on the healthcare system. In this study, a novel and modified LEAN methodology has been applied to embed the voice of the patient in care delivery processes and to reduce wait times to care in the management of complex chronic conditions.

  1. Act-and-wait time-delayed feedback control of nonautonomous systems

    Science.gov (United States)

    Pyragas, Viktoras; Pyragas, Kestutis

    2016-07-01

    Act-and-wait modification of a time-delayed feedback control (TDFC) algorithm is proposed to stabilize unstable periodic orbits in nonautonomous dynamical systems. Due to periodical switching on and off the control perturbation, an infinite-dimensional function space of the TDFC system is reduced to the finite-dimensional state space. As a result the number of Floquet exponents defining the stability of the controlled orbit remains the same as for the control-free system. The values of these exponents can be effectively manipulated by the variation of control parameters. We demonstrate the advantages of the modification for the chaotic nonautonomous Duffing oscillator with diagonal and nondiagonal control matrices. In both cases very deep minima of the spectral abscissa of Floquet exponents have been attained. The advantage of the modification is particularly remarkable for the nondiagonal coupling; in this case the conventional TDFC fails, whereas the modified version works.

  2. Exact and Heuristic Solutions to Minimize Total Waiting Time in the Blood Products Distribution Problem

    Directory of Open Access Journals (Sweden)

    Amir Salehipour

    2012-01-01

    Full Text Available This paper presents a novel application of operations research to support decision making in blood distribution management. The rapid and dynamic increasing demand, criticality of the product, storage, handling, and distribution requirements, and the different geographical locations of hospitals and medical centers have made blood distribution a complex and important problem. In this study, a real blood distribution problem containing 24 hospitals was tackled by the authors, and an exact approach was presented. The objective of the problem is to distribute blood and its products among hospitals and medical centers such that the total waiting time of those requiring the product is minimized. Following the exact solution, a hybrid heuristic algorithm is proposed. Computational experiments showed the optimal solutions could be obtained for medium size instances, while for larger instances the proposed hybrid heuristic is very competitive.

  3. Setting wait times to achieve targeted left-without-being-seen rates.

    Science.gov (United States)

    Lucas, Jared; Batt, Robert J; Soremekun, Olanrewaju A

    2014-04-01

    Although several studies have demonstrated that wait time is a key factor that drives high leave-without-being-seen (LWBS) rates, limited data on ideal wait times and impact on LWBS rates exist. We studied the LWBS rates by triage class and target wait times required to achieve various LWBS rates. We conducted a 3-year retrospective analysis of patients presenting to an urban, tertiary, academic, adult emergency department (ED). We divided the 3-year study period into 504 discrete periods by year, day of the week, and hour of the day. Patients of same triage level arriving in the same bin were exposed to similar ED conditions. For each bin, we calculate the mean actual wait time and the proportion of patients that abandoned. We performed a regression analysis on the abandonment proportion on the mean wait time using weighted least squares regression. A total of 143,698 patients were included for analysis during the study period. The R(2) value was highest for Emergency Severity Index (ESI) 3 (R(2) = 0.88), suggesting that wait time is the major factor driving LWBS of ESI 3 patients. Assuming that ESI 2 patients wait less than 10 minutes, our sensitivity analysis shows that the target wait times for ESI 3 and ESI 4/5 patients should be less than 45 and 60 minutes, respectively, to achieve an overall LWBS rate of less than 2%. Achieving target LWBS rates requires analysis to understand the abandonment behavior and redesigning operations to achieve the target wait times. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Indication criteria for cataract extraction and gender differences in waiting time.

    Science.gov (United States)

    Smirthwaite, Goldina; Lundström, Mats; Albrecht, Susanne; Swahnberg, Katarina

    2014-08-01

    The purpose of this study was to investigate national indication criteria tool for cataract extraction (NIKE), a clinical tool for establishing levels of indications for cataract surgery, in relation to gender differences in waiting times for cataract extraction (CE). Data were collected by The Swedish National Cataract Register (NCR). Eye clinics report to NCR voluntarily and on regular basis (98% coverage). Comparisons regarding gender difference in waiting times were performed between NIKE-categorized and non-NIKE-categorized patients, as well as between different indication groups within the NIKE-system. All calculations were performed in spss version 20. Multivariate analyses were carried out using logistic regression, and single variable analyses were carried out by Student's t-test or chi square as appropriate. Gender, age, visual acuity and NIKE-categorization were associated with waiting time. Female patients had a longer waiting time to CE than male, both within and outside the NIKE-system. Gender difference in waiting time was somewhat larger among patients who had not been categorized by NIKE. In the non-NIKE-categorized group, women waited 0.20 months longer than men. In the group which was NIKE-categorized, women waited 0.18 months longer than men. It is reasonable to assume that prioritizing patients by means of NIKE helps to reduce the gender differences in waiting time. Gender differences in waiting time have decreased as NIKE was introduced and there may be a variety of explanations for this. However, with the chosen study design, we could not distinguish between effects related to NIKE and those due to other factors which occurred during the study period. © 2013 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  5. Shorter Perceived Outpatient MRI Wait Times Associated With Higher Patient Satisfaction.

    Science.gov (United States)

    Holbrook, Anna; Glenn, Harold; Mahmood, Rabia; Cai, Qingpo; Kang, Jian; Duszak, Richard

    2016-05-01

    The aim of this study was to assess differences in perceived versus actual wait times among patients undergoing outpatient MRI examinations and to correlate those times with patient satisfaction. Over 15 weeks, 190 patients presenting for outpatient MR in a radiology department in which "patient experience" is one of the stated strategic priorities were asked to (1) estimate their wait times for various stages in the imaging process and (2) state their satisfaction with their imaging experience. Perceived times were compared with actual electronic time stamps. Perceived and actual times were compared and correlated with standardized satisfaction scores using Kendall τ correlation. The mean actual wait time between patient arrival and examination start was 53.4 ± 33.8 min, whereas patients perceived a mean wait time of 27.8 ± 23.1 min, a statistically significant underestimation of 25.6 min (P perceived wait times at all points during patient encounters were correlated with higher satisfaction scores (P perceived and actual wait times were both correlated with higher satisfaction scores. As satisfaction surveys play a larger role in an environment of metric transparency and value-based payments, better understanding of such factors will be increasingly important. Copyright © 2016 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  6. The ecology of the patient visit: physical attractiveness, waiting times, and perceived quality of care.

    Science.gov (United States)

    Becker, Franklin; Douglass, Stephanie

    2008-01-01

    This study examined the relationship between the attractiveness of the physical environment of healthcare facilities and patient perceptions of quality, service, and waiting time through systematic observations and patient satisfaction surveys at 7 outpatient practices at Weill Cornell Medical Center. Findings indicate positive correlations between more attractive environments and higher levels of perceived quality, satisfaction, staff interaction, and reduction of patient anxiety. The comparison of actual observed time and patients' perception of time showed that patients tend to overestimate shorter waiting times and underestimate longer waiting times in both the waiting area and the examination room. Further examinations of the way outpatient-practice environments impact patient and staff perceptions and how those perceptions impact behavior and medical outcomes are suggested.

  7. The waiting time distribution as a graphical approach to epidemiologic measures of drug utilization

    DEFF Research Database (Denmark)

    Hallas, J; Gaist, D; Bjerrum, L

    1997-01-01

    that effectively conveys some essential utilization parameters for a drug. The waiting time distribution for a group of drug users is a charting of their first prescription presentations within a specified time window. For a drug used for chronic treatment, most current users will be captured at the beginning...... of the window. After a few months, the graph will be dominated by new, incident users. As examples, we present waiting time distributions for insulin, ulcer drugs, systemic corticosteroids, antidepressants, and disulfiram. Appropriately analyzed and interpreted, the waiting time distributions can provide...... information about the period prevalence, point prevalence, incidence, duration of use, seasonality, and rate of prescription renewal or relapse for specific drugs. Each of these parameters has a visual correlate. The waiting time distributions may be an informative supplement to conventional drug utilization...

  8. Waiting time for cataract surgery and its influence on patient attitudes.

    Science.gov (United States)

    Chan, Frank Wan-kin; Fan, Alex Hoi; Wong, Fiona Yan-yan; Lam, Philip Tsze-ho; Yeoh, Eng-kiong; Yam, Carrie Ho-kwan; Griffiths, Sian; Lam, Dennis Shun-chiu; Congdon, Nathan

    2009-08-01

    To characterize willingness to pay for private operations and preferred waiting time among patients awaiting cataract surgery in Hong Kong. This was a cross-sectional survey. Subjects randomly selected from cataract surgical waiting lists in Hong Kong (n = 467) underwent a telephone interview based on a structured, validated questionnaire. Data were collected on private insurance coverage, preferred waiting time, amount willing to pay for surgery, and self-reported visual function and health status. Among 300 subjects completing the interview, 144 (48.2%) were 76 years of age or older, 177 (59%) were women, and mean time waiting for surgery was 17 +/- 15 months. Among 220 subjects (73.3%) willing to pay anything for surgery, the mean amount was US$552 +/- 443. With adjustment for age, education, and monthly household income, subjects willing to pay anything were less willing to wait 12 months for surgery (OR = 4.34; P = 0.002), more likely to know someone having had cataract surgery (OR = 2.20; P = 0.03), and more likely to use their own savings to pay for the surgery (OR = 2.21; P = 0.04). Subjects considering private cataract surgery, knowing people who have had cataract surgery, using nongovernment sources to pay for surgery, and having lower visual function were willing to pay more. Many patients wait significant periods for cataract surgery in Hong Kong, and are willing to pay substantial amounts for private operations. These results may have implications for other countries with cataract waiting lists.

  9. Asymptotic inference for waiting times and patiences in queues with abandonment

    DEFF Research Database (Denmark)

    Gorst-Rasmussen, Anders; Hansen, Martin Bøgsted

    Motivated by applications in call center management, we propose a framework based on empirical process techniques for inference about the waiting time and patience distribution in multiserver queues with abandonment. The framework rigorises heuristics based on survival analysis of independent...

  10. Asymptotic inference for waiting times and patiences in queues with abandonment

    DEFF Research Database (Denmark)

    Gorst-Rasmussen, Anders; Hansen, Martin Bøgsted

    2009-01-01

    Motivated by applications in call center management, we propose a framework based on empirical process techniques for inference about waiting time and patience distributions in multiserver queues with abandonment. The framework rigorises heuristics based on survival analysis of independent...

  11. Waiting room time: An opportunity for parental oral health education.

    Science.gov (United States)

    Soussou, Randa; Aleksejūnienė, Jolanta; Harrison, Rosamund

    2017-09-14

    The UBC Children's Dental Program (CDP) has provided free dental treatments to underserved low-income children, but its preventive component needs to be enhanced. The study aims were: 1) to develop a "waiting-room based" dental education program engaging caregivers of these children, and 2) to assess the program's feasibility, acceptability and effectiveness. In preparation, a situational analysis (SA) included structured interviews with caregivers, and with various stakeholders (e.g., dental students, instructors, health authority) involved in the CDP program. Based on the SA, caregiver-centered education was designed using an interactive power point presentation; after the presentation, each caregiver set personalized goals for modifying his/her child's dental behaviours. Evaluation of the program was done with follow-up telephone calls; the program's effectiveness was assessed by comparing before/after proportions of caregivers brushing their child's teeth, children brushing teeth in the morning and evening, children eating sugar-containing snacks, and children drinking sugar-containing drinks. The program proved to be easy to implement (feasible) and the recruitment rate was 99% (acceptable). The follow-up rate was 81%. The SA identified that the caregivers' knowledge about caries etiology and prevention was limited. All recruited caregivers completed the educational session and set goals for their family. The evaluation demonstrated an increase in caregiver-reported short-term diet and oral self-care behaviours of their children. A dental education program engaging caregivers in the waiting room was a feasible, acceptable and promising strategy for improving short-term dental behaviours of children.

  12. Public reporting on quality, waiting times and patient experience in 11 high-income countries

    OpenAIRE

    Rechel, Bernd; McKee, Martin; Haas, Marion; Marchildon, Gregory P; Bousquet, Frederic; Blümel, Miriam; Geissler, Alexander; van Ginneken, Ewout; Ashton, Toni; Saunes, Ingrid Sperre; Anell, Anders; Quentin, Wilm; Saltman, Richard; Culler, Steven; Barnes, Andrew

    2016-01-01

    : This article maps current approaches to public reporting on waiting times, patient experience and aggregate measures of quality and safety in 11 high-income countries (Australia, Canada, England, France, Germany, Netherlands, New Zealand, Norway, Sweden, Switzerland and the United States). Using a questionnaire-based survey of key national informants, we found that the data most commonly made available to the public are on waiting times for hospital treatment, being reported for major hospi...

  13. Intake of wine, beer and spirits and waiting time to pregnancy

    DEFF Research Database (Denmark)

    Juhl, Mette; Olsen, Jørn; Andersen, Anne-Marie Nybo

    2003-01-01

    A high intake of alcohol may prolong waiting time to pregnancy, whereas a moderate intake may have no or perhaps even a positive effect on fecundity. In previous studies on fecundity, different types of beverages have not been taken into consideration, although moderate wine drinkers appear to have...... fewer strokes, lung and digestive tract cancers, and overall mortality than both abstainers and moderate drinkers of beer or spirits. We examined the association between different types of alcoholic beverages and waiting time to pregnancy....

  14. Discrimination in waiting times by insurance type and financial soundness of German acute care hospitals.

    Science.gov (United States)

    Schwierz, Christoph; Wübker, Achim; Wübker, Ansgar; Kuchinke, Björn A

    2011-10-01

    This paper shows that patients with private health insurance (PHI) are being offered significantly shorter waiting times than patients with statutory health insurance (SHI) in German acute hospital care. This behavior may be driven by the higher expected profitability of PHI relative to SHI holders. Further, we find that hospitals offering private insurees shorter waiting times when compared with SHI holders have a significantly better financial performance than those abstaining from or with less discrimination.

  15. Using Queuing Theory and Simulation Modelling to Reduce Waiting Times in An Iranian Emergency Department

    OpenAIRE

    Haghighinejad, Hourvash Akbari; Kharazmi, Erfan; Hatam, Nahid; Yousefi, Sedigheh; Hesami, Seyed Ali; Danaei, Mina; Askarian, Mehrdad

    2016-01-01

    Background: Hospital emergencies have an essential role in health care systems. In the last decade, developed countries have paid great attention to overcrowding crisis in emergency departments. Simulation analysis of complex models for which conditions will change over time is much more effective than analytical solutions and emergency department (ED) is one of the most complex models for analysis. This study aimed to determine the number of patients who are waiting and waiting time in emerg...

  16. Waiting time and the psychosocial consequences of false-positive mammography

    DEFF Research Database (Denmark)

    Heleno, Bruno M.; Siersma, Volkert; Brodersen, John

    2015-01-01

    Background: There is wide variation in the psychosocial response to false-positive mammography. We aimed to assess whether women having to wait longer to exclude cancer had increased psychosocial consequences that persisted after cancer was ruled out. Findings: We selected women with false......-positive mammography (n = 272), screened for breast cancer in Copenhagen and Funen (Denmark) over a 1-year period. We measured psychosocial consequences immediately before women attended their recall visit and 1, 6, 18 and 36 months after women received their final diagnosis. After women were told that cancer had been...... ruled out, adverse psychosocial consequences decreased with time. We found no statistically significant differences between women who had cancer ruled out immediately at the recall visit (waiting time of 0) and women who had to wait longer before cancer was ruled out (waiting times 1-30, 30...

  17. Waiting time distribution revealing the internal spin dynamics in a double quantum dot

    Science.gov (United States)

    Ptaszyński, Krzysztof

    2017-07-01

    Waiting time distribution and the zero-frequency full counting statistics of unidirectional electron transport through a double quantum dot molecule attached to spin-polarized leads are analyzed using the quantum master equation. The waiting time distribution exhibits a nontrivial dependence on the value of the exchange coupling between the dots and the gradient of the applied magnetic field, which reveals the oscillations between the spin states of the molecule. The zero-frequency full counting statistics, on the other hand, is independent of the aforementioned quantities, thus giving no insight into the internal dynamics. The fact that the waiting time distribution and the zero-frequency full counting statistics give a nonequivalent information is associated with two factors. Firstly, it can be explained by the sensitivity to different timescales of the dynamics of the system. Secondly, it is associated with the presence of the correlation between subsequent waiting times, which makes the renewal theory, relating the full counting statistics and the waiting time distribution, no longer applicable. The study highlights the particular usefulness of the waiting time distribution for the analysis of the internal dynamics of mesoscopic systems.

  18. The impact of different prioritisation policies on waiting times: case studies of Norway and Scotland.

    Science.gov (United States)

    Januleviciute, Jurgita; Askildsen, Jan Erik; Kaarboe, Oddvar; Holmås, Tor Helge; Sutton, Matt

    2013-11-01

    We investigate the distributional consequences of two different waiting times initiatives, one in Norway, and one in Scotland. The primary focus of Scotland's recent waiting time reforms, introduced in 2003, and modified in 2005 and 2007, has been on reducing maximum waiting times through the imposition of high profile national targets accompanied by increases in resources. In Norway, the focus of the reform introduced in September 2004, has been on assigning patients referred to hospital a maximum waiting time based on disease severity, the expected benefit and the cost-effectiveness of the treatment. We use large, national administrative datasets from before and after each of these reforms and assign priority groups based on the maximum waiting times stipulated in medical guidelines. The analysis shows that the lowest priority patients benefited most from both reforms. This was at the cost of longer waiting times for patients that should have been given higher priority in Norway, while Scotland's high priority patients remained unaffected. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Using Queuing Theory and Simulation Modelling to Reduce Waiting Times in An Iranian Emergency Department.

    Science.gov (United States)

    Haghighinejad, Hourvash Akbari; Kharazmi, Erfan; Hatam, Nahid; Yousefi, Sedigheh; Hesami, Seyed Ali; Danaei, Mina; Askarian, Mehrdad

    2016-01-01

    Hospital emergencies have an essential role in health care systems. In the last decade, developed countries have paid great attention to overcrowding crisis in emergency departments. Simulation analysis of complex models for which conditions will change over time is much more effective than analytical solutions and emergency department (ED) is one of the most complex models for analysis. This study aimed to determine the number of patients who are waiting and waiting time in emergency department services in an Iranian hospital ED and to propose scenarios to reduce its queue and waiting time. This is a cross-sectional study in which simulation software (Arena, version 14) was used. The input information was extracted from the hospital database as well as through sampling. The objective was to evaluate the response variables of waiting time, number waiting and utilization of each server and test the three scenarios to improve them. Running the models for 30 days revealed that a total of 4088 patients left the ED after being served and 1238 patients waited in the queue for admission in the ED bed area at end of the run (actually these patients received services out of their defined capacity). The first scenario result in the number of beds had to be increased from 81 to179 in order that the number waiting of the "bed area" server become almost zero. The second scenario which attempted to limit hospitalization time in the ED bed area to the third quartile of the serving time distribution could decrease the number waiting to 586 patients. Doubling the bed capacity in the emergency department and consequently other resources and capacity appropriately can solve the problem. This includes bed capacity requirement for both critically ill and less critically ill patients. Classification of ED internal sections based on severity of illness instead of medical specialty is another solution.

  20. Discovering the impact of preceding units' characteristics on the wait time of cardiac surgery unit from statistic data.

    Science.gov (United States)

    Liu, Jiming; Tao, Li; Xiao, Bo

    2011-01-01

    Prior research shows that clinical demand and supplier capacity significantly affect the throughput and the wait time within an isolated unit. However, it is doubtful whether characteristics (i.e., demand, capacity, throughput, and wait time) of one unit would affect the wait time of subsequent units on the patient flow process. Focusing on cardiac care, this paper aims to examine the impact of characteristics of the catheterization unit (CU) on the wait time of cardiac surgery unit (SU). This study integrates published data from several sources on characteristics of the CU and SU units in 11 hospitals in Ontario, Canada between 2005 and 2008. It proposes a two-layer wait time model (with each layer representing one unit) to examine the impact of CU's characteristics on the wait time of SU and test the hypotheses using the Partial Least Squares-based Structural Equation Modeling analysis tool. Results show that: (i) wait time of CU has a direct positive impact on wait time of SU (β = 0.330, p relationships among different characteristics (except for the effect of throughput on wait time in SU). Characteristics of CU have direct and indirect impacts on wait time of SU. Specifically, demand and wait time of preceding unit are good predictors for wait time of subsequent units. This suggests that considering such cross-unit effects is necessary when alleviating wait time in a health care system. Further, different patient risk profiles may affect wait time in different ways (e.g., positive or negative effects) within SU. This implies that the wait time management should carefully consider the relationship between priority triage and risk stratification, especially for cardiac surgery.

  1. Discovering the impact of preceding units' characteristics on the wait time of cardiac surgery unit from statistic data.

    Directory of Open Access Journals (Sweden)

    Jiming Liu

    Full Text Available INTRODUCTION: Prior research shows that clinical demand and supplier capacity significantly affect the throughput and the wait time within an isolated unit. However, it is doubtful whether characteristics (i.e., demand, capacity, throughput, and wait time of one unit would affect the wait time of subsequent units on the patient flow process. Focusing on cardiac care, this paper aims to examine the impact of characteristics of the catheterization unit (CU on the wait time of cardiac surgery unit (SU. METHODS: This study integrates published data from several sources on characteristics of the CU and SU units in 11 hospitals in Ontario, Canada between 2005 and 2008. It proposes a two-layer wait time model (with each layer representing one unit to examine the impact of CU's characteristics on the wait time of SU and test the hypotheses using the Partial Least Squares-based Structural Equation Modeling analysis tool. RESULTS: Results show that: (i wait time of CU has a direct positive impact on wait time of SU (β = 0.330, p < 0.01; (ii capacity of CU has a direct positive impact on demand of SU (β = 0.644, p < 0.01; (iii within each unit, there exist significant relationships among different characteristics (except for the effect of throughput on wait time in SU. CONCLUSION: Characteristics of CU have direct and indirect impacts on wait time of SU. Specifically, demand and wait time of preceding unit are good predictors for wait time of subsequent units. This suggests that considering such cross-unit effects is necessary when alleviating wait time in a health care system. Further, different patient risk profiles may affect wait time in different ways (e.g., positive or negative effects within SU. This implies that the wait time management should carefully consider the relationship between priority triage and risk stratification, especially for cardiac surgery.

  2. [Reducing patient waiting time for the outpatient phlebotomy service using six sigma].

    Science.gov (United States)

    Kim, Yu Kyung; Song, Kyung Eun; Lee, Won Kil

    2009-04-01

    One of the challenging issues of the outpatient phlebotomy services at most hospitals is that patients have a long wait. The outpatient phlebotomy team of Kyungpook National University Hospital applied six sigma breakthrough methodologies to reduce the patient waiting time. The DMAIC (Define, Measure, Analyze, Improve, and Control) model was employed to approach the project. Two hundred patients visiting the outpatient phlebotomy section were asked to answer the questionnaires at inception of the study to ascertain root causes. After correction, we surveyed 285 patients for same questionnaires again to follow-up the effects. A defect was defined as extending patient waiting time so long and at the beginning of the project, the performance level was 2.61 sigma. Using fishbone diagram, all the possible reasons for extending patient waiting time were captured, and among them, 16 causes were proven to be statistically significant. Improvement plans including a new receptionist, automatic specimen transport system, and adding one phlebotomist were put into practice. As a result, the number of patients waited more than 5 min significantly decreased, and the performance level reached 3.0 sigma in December 2007 and finally 3.35 sigma in July 2008. Applying the six sigma, the performance level of waiting times for blood drawing exceeding five minutes were improved from 2.61 sigma to 3.35 sigma.

  3. Waiting times for diagnosis and treatment of head and neck cancer in Denmark in 2010 compared to 1992 and 2002

    DEFF Research Database (Denmark)

    Lyhne, N M; Christensen, A; Alanin, M C

    2013-01-01

    BACKGROUND AND AIM: Significant tumour progression was observed during waiting time for treatment of head and neck cancer. To reduce waiting times, a Danish national policy of fast track accelerated clinical pathways was introduced in 2007. This study describes changes in waiting time and the pot......BACKGROUND AND AIM: Significant tumour progression was observed during waiting time for treatment of head and neck cancer. To reduce waiting times, a Danish national policy of fast track accelerated clinical pathways was introduced in 2007. This study describes changes in waiting time...... and the potential influence of fast track by comparing waiting times in 2010 to 2002 and 1992. METHODS: Charts of all new patients diagnosed with squamous cell carcinoma of the oral cavity, pharynx and larynx at the five Danish head and neck oncology centres from January to April 2010 (n=253) were reviewed...

  4. Sci-Fri AM: Quality, Safety, and Professional Issues 04: Predicting waiting times in Radiation Oncology using machine learning

    International Nuclear Information System (INIS)

    Joseph, Ackeem; Herrera, David; Hijal, Tarek; Hendren, Laurie; Leung, Alvin; Wainberg, Justin; Sawaf, Marya; Maxim, Gorshkov; Maglieri, Robert; Keshavarz, Mehryar; Kildea, John

    2016-01-01

    We describe a method for predicting waiting times in radiation oncology. Machine learning is a powerful predictive modelling tool that benefits from large, potentially complex, datasets. The essence of machine learning is to predict future outcomes by learning from previous experience. The patient waiting experience remains one of the most vexing challenges facing healthcare. Waiting time uncertainty can cause patients, who are already sick and in pain, to worry about when they will receive the care they need. In radiation oncology, patients typically experience three types of waiting: Waiting at home for their treatment plan to be prepared Waiting in the waiting room for daily radiotherapy Waiting in the waiting room to see a physician in consultation or follow-up These waiting periods are difficult for staff to predict and only rough estimates are typically provided, based on personal experience. In the present era of electronic health records, waiting times need not be so uncertain. At our centre, we have incorporated the electronic treatment records of all previously-treated patients into our machine learning model. We found that the Random Forest Regression model provides the best predictions for daily radiotherapy treatment waiting times (type 2). Using this model, we achieved a median residual (actual minus predicted value) of 0.25 minutes and a standard deviation residual of 6.5 minutes. The main features that generated the best fit model (from most to least significant) are: Allocated time, median past duration, fraction number and the number of treatment fields.

  5. Sci-Fri AM: Quality, Safety, and Professional Issues 04: Predicting waiting times in Radiation Oncology using machine learning

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, Ackeem; Herrera, David; Hijal, Tarek; Hendren, Laurie; Leung, Alvin; Wainberg, Justin; Sawaf, Marya; Maxim, Gorshkov; Maglieri, Robert; Keshavarz, Mehryar; Kildea, John [McGill University Health Centre (Canada)

    2016-08-15

    We describe a method for predicting waiting times in radiation oncology. Machine learning is a powerful predictive modelling tool that benefits from large, potentially complex, datasets. The essence of machine learning is to predict future outcomes by learning from previous experience. The patient waiting experience remains one of the most vexing challenges facing healthcare. Waiting time uncertainty can cause patients, who are already sick and in pain, to worry about when they will receive the care they need. In radiation oncology, patients typically experience three types of waiting: Waiting at home for their treatment plan to be prepared Waiting in the waiting room for daily radiotherapy Waiting in the waiting room to see a physician in consultation or follow-up These waiting periods are difficult for staff to predict and only rough estimates are typically provided, based on personal experience. In the present era of electronic health records, waiting times need not be so uncertain. At our centre, we have incorporated the electronic treatment records of all previously-treated patients into our machine learning model. We found that the Random Forest Regression model provides the best predictions for daily radiotherapy treatment waiting times (type 2). Using this model, we achieved a median residual (actual minus predicted value) of 0.25 minutes and a standard deviation residual of 6.5 minutes. The main features that generated the best fit model (from most to least significant) are: Allocated time, median past duration, fraction number and the number of treatment fields.

  6. Determinants of variability in waiting times for radiotherapy in the treatment of breast cancer

    International Nuclear Information System (INIS)

    Bouche, Gauthier; Ingrand, Isabelle; Mathoulin-Pelissier, Simone; Ingrand, Pierre; Breton-Callu, Christel; Migeot, Virginie

    2010-01-01

    Purpose: To examine psycho-social and geographic determinants of delay in starting radiotherapy in early invasive breast cancer patients. Material and methods: Waiting time was defined as the time elapsed until the beginning of radiotherapy, starting from the date of surgery (in absence of chemotherapy) or from the end of chemotherapy. Results: Eight hundred and ninety six women aged 24-89 took part in the study. Mean waiting times were 52 days (sd = 19) between surgery and radiotherapy and 31 days (sd = 14) between chemotherapy and radiotherapy. Differences between radiotherapy centres (p < 0.0001) accounted for 30% and 12%, respectively, of total variance in waiting times. Using a multivariate mixed analysis that took into account intra-centre correlation, the time between surgery and radiotherapy was shorter for young patients (p = 0.020), those who had sought information about their illness (p = 0.024) and those who had undergone surgery and radiotherapy in the same centre (p = 0.021). On the other hand, no patient characteristic was associated with the time between chemotherapy and radiotherapy. Conclusion: Centre is the major factor that explained longer waiting times in radiotherapy, emphasising the structural hypothesis. It is important to pursue initiatives to improve the organization within radiotherapy centres and then to verify that these initiatives have succeeded in shortening waiting times.

  7. Socioeconomic differences in waiting times for elective surgery: a population-based retrospective study

    Directory of Open Access Journals (Sweden)

    Petrelli Alessio

    2012-08-01

    Full Text Available Abstract Background Widespread literature on inequity in healthcare access and utilization has been published, but research on socioeconomic differences in waiting times is sparse and the evidence is fragmentary and controversial. The objective of the present study is the analysis of the relationship between individual socioeconomic level and waiting times for in-hospital elective surgery. Methods We retrospectively studied the waiting times experienced by patients registered on hospital waiting lists for 6 important surgical procedures by using the Hospital Discharge Database (HDD of the Piedmont Region (4,000,000 inhabitants in the North West of Italy from 2006 to 2008. The surgical procedures analyzed were: coronary artery by-pass (CABG, angioplasty, coronarography, endarterectomy, hip replacement and cholecystectomy. Cox regression models were estimated to study the relationship between waiting times and educational level taking into account the confounding effect of the following factors: sex, age, comorbidity, registration period, and Local Health Authorities (LHA as a proxy of supply. Results Median waiting times for low educational level were higher than for high educational level for all the selected procedures. Differences were particularly high for endarterectomy and hip replacement. For all considered procedures, except CABG, an inverse gradient between waiting times and educational level was observed: the conditional probabilities of undergoing surgery were lower among individuals with a low to middle level education than for individuals with a higher level of education after adjustment for sex, age, comorbidities, registration period, and LHAs. For most procedures the effect decreases over the follow up period. Conclusions The results of the study show evidence of inequalities in access to elective surgery in Italy. Implementation of policies aimed to promote national information initiatives that guarantee wider access to those

  8. Using Queuing Theory and Simulation Modelling to Reduce Waiting Times in An Iranian Emergency Department

    Directory of Open Access Journals (Sweden)

    Hourvash Akbari Haghighinejad

    2016-01-01

    Full Text Available Background: Hospital emergencies have an essential role in health care systems. In the last decade, developed countries have paid great attention to overcrowding crisis in emergency departments. Simulation analysis of complex models for which conditions will change over time is much more effective than analytical solutions and emergency department (ED is one of the most complex models for analysis. This study aimed to determine the number of patients who are waiting and waiting time in emergency department services in an Iranian hospital ED and to propose scenarios to reduce its queue and waiting time. Methods: This is a cross-sectional study in which simulation software (Arena, version 14 was used. The input information was extracted from the hospital database as well as through sampling. The objective was to evaluate the response variables of waiting time, number waiting and utilization of each server and test the three scenarios to improve them. Results: Running the models for 30 days revealed that a total of 4088 patients left the ED after being served and 1238 patients waited in the queue for admission in the ED bed area at end of the run (actually these patients received services out of their defined capacity. The first scenario result in the number of beds had to be increased from 81 to179 in order that the number waiting of the “bed area” server become almost zero. The second scenario which attempted to limit hospitalization time in the ED bed area to the third quartile of the serving time distribution could decrease the numberwaiting to 586 patients. Conclusion: Doubling the bed capacity in the emergency department and consequently other resources and capacity appropriately can solve the problem. This includes bed capacity requirement for both critically ill and less critically ill patients. Classification of ED internal sections based on severity of illness instead of medical specialty is another solution.

  9. The 2012 SAGE wait times program: Survey of Access to GastroEnterology in Canada

    Science.gov (United States)

    Leddin, Desmond; Armstrong, David; Borgaonkar, Mark; Bridges, Ronald J; Fallone, Carlo A; Telford, Jennifer J; Chen, Ying; Colacino, Palma; Sinclair, Paul

    2013-01-01

    BACKGROUND: Periodically surveying wait times for specialist health services in Canada captures current data and enables comparisons with previous surveys to identify changes over time. METHODS: During one week in April 2012, Canadian gastroenterologists were asked to complete a questionnaire (online or by fax) recording demographics, reason for referral, and dates of referral and specialist visits for at least 10 consecutive new patients (five consultations and five procedures) who had not been seen previously for the same indication. Wait times were determined for 18 indications and compared with those from similar surveys conducted in 2008 and 2005. RESULTS: Data regarding adult patients were provided by 173 gastroenterologists for 1374 consultations, 540 procedures and 293 same-day consultations and procedures. Nationally, the median wait times were 92 days (95% CI 85 days to 100 days) from referral to consultation, 55 days (95% CI 50 days to 61 days) from consultation to procedure and 155 days (95% CI 142 days to 175 days) (total) from referral to procedure. Overall, wait times were longer in 2012 than in 2005 (Pgastroenterology services continue to exceed recommended targets, remain unchanged since 2008 and exceed wait times reported in 2005. PMID:23472243

  10. Posted wait times an added advantage to multi-facility systems?

    Science.gov (United States)

    2011-04-01

    Methodist Le Bonheur Healthcare in Memphis, TN, is investigating whether posting ED wait times via the internet can positively impact patient flow in the six EDs the health system operates in the Memphis region. The health system began posting wait times in August 2010, resulting in increases in ED volume ranging from 6% to 10%. The health system is monitoring ED arrivals by zip code to assess any impact on load balancing between its busy EDs. One marketing challenge is that a competitor is posting ED wait times as well, but it is posting the time it takes for a patient to be placed in a bed as opposed to the door-to-provider time that Methodist Le Bonheur is posting. The approach has the most impact on lower-acuity patients, but experts worry that in the future, payers may not be reimbursed for ED care for these patients.

  11. Effect of socioeconomic deprivation on waiting time for cardiac surgery: retrospective cohort study

    Science.gov (United States)

    Pell, Jill P; Pell, Alastair C H; Norrie, John; Ford, Ian; Cobbe, Stuart M

    2000-01-01

    Objective To determine whether the priority given to patients referred for cardiac surgery is associated with socioeconomic status. Design Retrospective study with multivariate logistic regression analysis of the association between deprivation and classification of urgency with allowance for age, sex, and type of operation. Multivariate linear regression analysis was used to determine association between deprivation and waiting time within each category of urgency, with allowance for age, sex, and type of operation. Setting NHS waiting lists in Scotland. Participants 26 642 patients waiting for cardiac surgery, 1 January 1986 to 31 December 1997. Main outcome measures Deprivation as measured by Carstairs deprivation category. Time spent on NHS waiting list. Results Patients who were most deprived tended to be younger and were more likely to be female. Patients in deprivation categories 6 and 7 (most deprived) waited about three weeks longer for surgery than those in category 1 (mean difference 24 days, 95% confidence interval 15 to 32). Deprived patients had an odds ratio of 0.5 (0.46 to 0.61) for having their operations classified as urgent compared with the least deprived, after allowance for age, sex, and type of operation. When urgent and routine cases were considered separately, there was no significant difference in waiting times between the most and least deprived categories. Conclusions Socioeconomically deprived patients are thought to be more likely to develop coronary heart disease but are less likely to be investigated and offered surgery once it has developed. Such patients may be further disadvantaged by having to wait longer for surgery because of being given lower priority. PMID:10617517

  12. Estimating the waiting time of multi-priority emergency patients with downstream blocking.

    Science.gov (United States)

    Lin, Di; Patrick, Jonathan; Labeau, Fabrice

    2014-03-01

    To characterize the coupling effect between patient flow to access the emergency department (ED) and that to access the inpatient unit (IU), we develop a model with two connected queues: one upstream queue for the patient flow to access the ED and one downstream queue for the patient flow to access the IU. Building on this patient flow model, we employ queueing theory to estimate the average waiting time across patients. Using priority specific wait time targets, we further estimate the necessary number of ED and IU resources. Finally, we investigate how an alternative way of accessing ED (Fast Track) impacts the average waiting time of patients as well as the necessary number of ED/IU resources. This model as well as the analysis on patient flow can help the designer or manager of a hospital make decisions on the allocation of ED/IU resources in a hospital.

  13. Intake of wine, beer and spirits and waiting time to pregnancy

    DEFF Research Database (Denmark)

    Juhl, Mette; Olsen, Jørn; Andersen, Anne-Marie Nybo

    2003-01-01

    BACKGROUND: A high intake of alcohol may prolong waiting time to pregnancy, whereas a moderate intake may have no or perhaps even a positive effect on fecundity. In previous studies on fecundity, different types of beverages have not been taken into consideration, although moderate wine drinkers...... appear to have fewer strokes, lung and digestive tract cancers, and overall mortality than both abstainers and moderate drinkers of beer or spirits. We examined the association between different types of alcoholic beverages and waiting time to pregnancy. METHODS: Self-reported data were used for 29......,844 pregnant women, recruited to the Danish National Birth Cohort in 1997-2000. Main outcome measures were odds ratios for a prolonged waiting time to pregnancy according to consumption of wine, beer and spirits. RESULTS: All levels of wine intake compared with non-wine drinking or with consumption of beer...

  14. Wait times in the emergency department for patients with mental illness

    Science.gov (United States)

    Atzema, Clare L.; Schull, Michael J.; Kurdyak, Paul; Menezes, Natasja M.; Wilton, Andrew S.; Vermuelen, Marian J.; Austin, Peter C.

    2012-01-01

    Background: It has been suggested that patients with mental illness wait longer for care than other patients in the emergency department. We determined wait times for patients with and without mental health diagnoses during crowded and noncrowded periods in the emergency department. Methods: We conducted a population-based retrospective cohort analysis of adults seen in 155 emergency departments in Ontario between April 2007 and March 2009. We compared wait times and triage scores for patients with mental illness to those for all other patients who presented to the emergency department during the study period. Results: The patients with mental illness (n = 51 381) received higher priority triage scores than other patients, regardless of crowding. The time to assessment by a physician was longer overall for patients with mental illness than for other patients (median 82, interquartile range [IQR] 41–147 min v. median 75 [IQR 36–140] min; p < 0.001). The median time from the decision to admit the patient to hospital to ward transfer was markedly shorter for patients with mental illness than for other patients (median 74 [IQR 15–215] min v. median 152 [IQR 45–605] min; p < 0.001). After adjustment for other variables, patients with mental illness waited 10 minutes longer to see a physician compared with other patients during noncrowded periods (95% confidence interval [CI] 8 to 11), but they waited significantly less time than other patients as crowding increased (mild crowding: −14 [95% CI −12 to −15] min; moderate crowding: −38 [95% CI −35 to −42] min; severe crowding: −48 [95% CI −39 to −56] min; p < 0.001). Interpretation: Patients with mental illness were triaged appropriately in Ontario’s emergency departments. These patients waited less time than other patients to see a physician under crowded conditions and only slightly longer under noncrowded conditions. PMID:23148052

  15. Patient satisfaction with wait times at an emergency ophthalmology on-call service.

    Science.gov (United States)

    Chan, Brian J; Barbosa, Joshua; Moinul, Prima; Sivachandran, Nirojini; Donaldson, Laura; Zhao, Lily; Mullen, Sarah J; McLaughlin, Christopher R; Chaudhary, Varun

    2018-04-01

    To assess patient satisfaction with emergency ophthalmology care and determine the effect provision of anticipated appointment wait time has on scores. Single-centre, randomized control trial. Fifty patients triaged at the Hamilton Regional Eye Institute (HREI) from November 2015 to July 2016. Fifty patients triaged for next-day appointments at the HREI were randomly assigned to receive standard-of-care preappointment information or standard-of-care information in addition to an estimated appointment wait time. Patient satisfaction with care was assessed postvisit using the modified Judgements of Hospital Quality Questionnaire (JHQQ). In determining how informing patients of typical wait times influenced satisfaction, the Mann-Whitney U test was performed. As secondary study outcomes, we sought to determine patient satisfaction with the intervention material using the Fisher exact test and the effect that wait time, age, sex, education, mobility, and number of health care providers seen had on satisfaction scores using logistic regression analysis. The median JHQQ response was "very good" (4/5) and between "very good" and "excellent" (4.5/5) in the intervention and control arms, respectively. There was no difference in patient satisfaction between the cohorts (Mann-Whitney U = 297.00, p = 0.964). Logistic regression analysis demonstrated that wait times influenced patient satisfaction (OR = 0.919, 95% CI 0.864-0.978, p = 0.008). Of the intervention arm patients, 92.0% (N = 23) found the preappointment information useful, whereas only 12.5% (N = 3) of the control cohort patients noted the same (p < 0.001). Provision of anticipated wait time information to patients in an emergency on-call ophthalmology clinic did not influence satisfaction with care as captured by the JHQQ. Copyright © 2018 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

  16. Waiting for the right time: how and why young Thai women manage to avoid heterosexual intercourse.

    Science.gov (United States)

    Supametaporn, Pinhatai; Stern, Phyllis Noerager; Rodcumdee, Branom; Chaiyawat, Waraporn

    2010-08-01

    Nineteen young Thai women were purposively selected from networks of nongovernmental organizations involving children and youths in Bangkok. Our grounded theory findings indicated that these young women used the basic social process they called "waiting for the right time" in order to maintain heterosexual abstinence. Waiting for the right time involved one overarching condition, honoring parental love, and included three overlapping properties: learning rules, planning life path, and ways of preserving virginity. The findings provide information that may lead to the development of culturally competent interventions for middle-class Thai youths to remain healthy and avoid pregnancy.

  17. Waiting-time approximations in multi-queue systems with cyclic service

    NARCIS (Netherlands)

    Boxma, O.J.; Meister, B.W.

    1987-01-01

    This study is devoted to mean waiting-time approximations in a single-server multi-queue model with cyclic service and zero switching times of the server between consecutive queues. Two different service disciplines are considered: exhaustive service and (ordinary cyclic) nonexhaustive service. For

  18. Determinants of Patient Waiting Time in the General Outpatient ...

    African Journals Online (AJOL)

    The Institute of Medicine (IOM) recommends that, at least 90% of patients should be seen within 30 min of their scheduled appointment time.[5] This is, however, not the case in most developing countries, as several studies have shown that patients spend 2‑4 h in the outpatient departments before seeing the doctor.[6‑8] A ...

  19. WAITING TIME DISTRIBUTION OF SOLAR ENERGETIC PARTICLE EVENTS MODELED WITH A NON-STATIONARY POISSON PROCESS

    International Nuclear Information System (INIS)

    Li, C.; Su, W.; Fang, C.; Zhong, S. J.; Wang, L.

    2014-01-01

    We present a study of the waiting time distributions (WTDs) of solar energetic particle (SEP) events observed with the spacecraft WIND and GOES. The WTDs of both solar electron events (SEEs) and solar proton events (SPEs) display a power-law tail of ∼Δt –γ . The SEEs display a broken power-law WTD. The power-law index is γ 1 = 0.99 for the short waiting times (<70 hr) and γ 2 = 1.92 for large waiting times (>100 hr). The break of the WTD of SEEs is probably due to the modulation of the corotating interaction regions. The power-law index, γ ∼ 1.82, is derived for the WTD of the SPEs which is consistent with the WTD of type II radio bursts, indicating a close relationship between the shock wave and the production of energetic protons. The WTDs of SEP events can be modeled with a non-stationary Poisson process, which was proposed to understand the waiting time statistics of solar flares. We generalize the method and find that, if the SEP event rate λ = 1/Δt varies as the time distribution of event rate f(λ) = Aλ –α exp (– βλ), the time-dependent Poisson distribution can produce a power-law tail WTD of ∼Δt α –3 , where 0 ≤ α < 2

  20. Practical Solutions for Reducing Container Ships’ Waiting Times at Ports Using Simulation Model

    Institute of Scientific and Technical Information of China (English)

    Abdorreza Sheikholeslami; Gholamreza Ilati; Yones Eftekhari Yeganeh

    2013-01-01

    The main challenge for container ports is the planning required for berthing container ships while docked in port. Growth of containerization is creating problems for ports and container terminals as they reach their capacity limits of various resources which increasingly leads to traffic and port congestion. Good planning and management of container terminal operations reduces waiting time for liner ships. Reducing the waiting time improves the terminal’s productivity and decreases the port difficulties. Two important keys to reducing waiting time with berth allocation are determining suitable access channel depths and increasing the number of berths which in this paper are studied and analyzed as practical solutions. Simulation based analysis is the only way to understand how various resources interact with each other and how they are affected in the berthing time of ships. We used the Enterprise Dynamics software to produce simulation models due to the complexity and nature of the problems. We further present case study for berth allocation simulation of the biggest container terminal in Iran and the optimum access channel depth and the number of berths are obtained from simulation results. The results show a significant reduction in the waiting time for container ships and can be useful for major functions in operations and development of container ship terminals.

  1. Reducing waiting time and raising outpatient satisfaction in a Chinese public tertiary general hospital-an interrupted time series study

    Directory of Open Access Journals (Sweden)

    Jing Sun

    2017-08-01

    Full Text Available Abstract Background It is globally agreed that a well-designed health system deliver timely and convenient access to health services for all patients. Many interventions aiming to reduce waiting times have been implemented in Chinese public tertiary hospitals to improve patients’ satisfaction. However, few were well-documented, and the effects were rarely measured with robust methods. Methods We conducted a longitudinal study of the length of waiting times in a public tertiary hospital in Southern China which developed comprehensive data collection systems. Around an average of 60,000 outpatients and 70,000 prescribed outpatients per month were targeted for the study during Oct 2014-February 2017. We analyzed longitudinal time series data using a segmented linear regression model to assess changes in levels and trends of waiting times before and after the introduction of waiting time reduction interventions. Pearson correlation analysis was conducted to indicate the strength of association between waiting times and patient satisfactions. The statistical significance level was set at 0.05. Results The monthly average length of waiting time decreased 3.49 min (P = 0.003 for consultations and 8.70 min (P = 0.02 for filling prescriptions in the corresponding month when respective interventions were introduced. The trend shifted from baseline slight increasing to afterwards significant decreasing for filling prescriptions (P =0.003. There was a significant negative correlation between waiting time of filling prescriptions and outpatient satisfaction towards pharmacy services (r = −0.71, P = 0.004. Conclusions The interventions aimed at reducing waiting time and raising patient satisfaction in Fujian Provincial Hospital are effective. A long-lasting reduction effect on waiting time for filling prescriptions was observed because of carefully designed continuous efforts, rather than a one-time campaign, and with appropriate incentives

  2. Reducing waiting time and raising outpatient satisfaction in a Chinese public tertiary general hospital-an interrupted time series study.

    Science.gov (United States)

    Sun, Jing; Lin, Qian; Zhao, Pengyu; Zhang, Qiongyao; Xu, Kai; Chen, Huiying; Hu, Cecile Jia; Stuntz, Mark; Li, Hong; Liu, Yuanli

    2017-08-22

    It is globally agreed that a well-designed health system deliver timely and convenient access to health services for all patients. Many interventions aiming to reduce waiting times have been implemented in Chinese public tertiary hospitals to improve patients' satisfaction. However, few were well-documented, and the effects were rarely measured with robust methods. We conducted a longitudinal study of the length of waiting times in a public tertiary hospital in Southern China which developed comprehensive data collection systems. Around an average of 60,000 outpatients and 70,000 prescribed outpatients per month were targeted for the study during Oct 2014-February 2017. We analyzed longitudinal time series data using a segmented linear regression model to assess changes in levels and trends of waiting times before and after the introduction of waiting time reduction interventions. Pearson correlation analysis was conducted to indicate the strength of association between waiting times and patient satisfactions. The statistical significance level was set at 0.05. The monthly average length of waiting time decreased 3.49 min (P = 0.003) for consultations and 8.70 min (P = 0.02) for filling prescriptions in the corresponding month when respective interventions were introduced. The trend shifted from baseline slight increasing to afterwards significant decreasing for filling prescriptions (P =0.003). There was a significant negative correlation between waiting time of filling prescriptions and outpatient satisfaction towards pharmacy services (r = -0.71, P = 0.004). The interventions aimed at reducing waiting time and raising patient satisfaction in Fujian Provincial Hospital are effective. A long-lasting reduction effect on waiting time for filling prescriptions was observed because of carefully designed continuous efforts, rather than a one-time campaign, and with appropriate incentives implemented by a taskforce authorized by the hospital managers. This

  3. Access to specialist gastroenterology care in Canada: Comparison of wait times and consensus targets

    Science.gov (United States)

    Leddin, Desmond; Armstrong, David; Barkun, Alan NG; Chen, Ying; Daniels, Sandra; Hollingworth, Roger; Hunt, Richard H; Paterson, William G

    2008-01-01

    BACKGROUND: Monitoring wait times and defining targets for care have been advocated to improve health care delivery related to cancer, heart, diagnostic imaging, joint replacements and sight restoration. There are few data on access to care for digestive diseases, although they pose a greater economic burden than cancer or heart disease in Canada. The present study compared wait times for specialist gastroenterology care with recent, evidence-based, consensus-defined benchmark wait times for a range of digestive diseases. METHODS: Total wait times from primary care referral to investigation were measured for seven digestive disease indications by using the Practice Audit in Gastroenterology program, and were benchmarked against consensus recommendations. RESULTS: Total wait times for 1903 patients who were undergoing investigation exceeded targets for those with probable cancer (median 26 days [25th to 75th percentiles eight to 56 days] versus target of two weeks); probable inflammatory bowel disease (101 days [35 to 209 days] versus two weeks); documented iron deficiency anemia (71 days [19 to 142 days] versus two months); positive fecal occult blood test (73 days [36 to 148 days] versus two months); dyspepsia with alarm symptoms (60 days [23 to 140 days] versus two months); refractory dyspepsia without alarm symptoms (126 days [42 to 225 days] versus two months); and chronic constipation and diarrhea (141 days [68 to 264 days] versus two months). A minority of patients were seen within target times: probable cancer (33% [95% CI 20% to 47%]); probable inflammatory bowel disease (12% [95% CI 1% to 23%]); iron deficiency anemia (46% [95% CI 37% to 55%]); positive occult blood test (41% [95% CI 28% to 54%]); dyspepsia with alarm symptoms (51% [95% CI 41% to 60%]); refractory dyspepsia without alarm symptoms (33% [95% CI 19% to 47%]); and chronic constipation and diarrhea (21% [95% CI 14% to 29%]). DISCUSSION: Total wait times for the seven indications exceeded the

  4. Decreasing Psychiatric Admission Wait Time in the Emergency Department by Facilitating Psychiatric Discharges.

    Science.gov (United States)

    Stover, Pamela R; Harpin, Scott

    2015-12-01

    Limited capacity in a psychiatric unit contributes to long emergency department (ED) admission wait times. Regulatory and accrediting agencies urge hospitals nationally to improve patient flow for better access to care for all types of patients. The purpose of the current study was to decrease psychiatric admission wait time from 10.5 to 8 hours and increase the proportion of patients discharged by 11 a.m. from 20% to 50%. The current study compared pre- and post-intervention data. Plan-Do-Study-Act cycles aimed to improve discharge processes and timeliness through initiation of new practices. Admission wait time improved to an average of 5.1 hours (t = 3.87, p = 0.006). The proportion of discharges occurring by 11 a.m. increased to 46% (odds ratio = 3.42, p planning processes and timeliness in a psychiatric unit significantly decreased admission wait time from the ED, improving access to psychiatric care. Copyright 2015, SLACK Incorporated.

  5. A study on the impact of prioritising emergency department arrivals on the patient waiting time.

    Science.gov (United States)

    Van Bockstal, Ellen; Maenhout, Broos

    2018-05-03

    In the past decade, the crowding of the emergency department has gained considerable attention of researchers as the number of medical service providers is typically insufficient to fulfil the demand for emergency care. In this paper, we solve the stochastic emergency department workforce planning problem and consider the planning of nurses and physicians simultaneously for a real-life case study in Belgium. We study the patient arrival pattern of the emergency department in depth and consider different patient acuity classes by disaggregating the arrival pattern. We determine the personnel staffing requirements and the design of the shifts based on the patient arrival rates per acuity class such that the resource staffing cost and the weighted patient waiting time are minimised. In order to solve this multi-objective optimisation problem, we construct a Pareto set of optimal solutions via the -constraints method. For a particular staffing composition, the proposed model minimises the patient waiting time subject to upper bounds on the staffing size using the Sample Average Approximation Method. In our computational experiments, we discern the impact of prioritising the emergency department arrivals. Triaging results in lower patient waiting times for higher priority acuity classes and to a higher waiting time for the lowest priority class, which does not require immediate care. Moreover, we perform a sensitivity analysis to verify the impact of the arrival and service pattern characteristics, the prioritisation weights between different acuity classes and the incorporated shift flexibility in the model.

  6. Minimizing patient waiting time in emergency department of public hospital using simulation optimization approach

    Science.gov (United States)

    Ibrahim, Ireen Munira; Liong, Choong-Yeun; Bakar, Sakhinah Abu; Ahmad, Norazura; Najmuddin, Ahmad Farid

    2017-04-01

    Emergency department (ED) is the main unit of a hospital that provides emergency treatment. Operating 24 hours a day with limited number of resources invites more problems to the current chaotic situation in some hospitals in Malaysia. Delays in getting treatments that caused patients to wait for a long period of time are among the frequent complaints against government hospitals. Therefore, the ED management needs a model that can be used to examine and understand resource capacity which can assist the hospital managers to reduce patients waiting time. Simulation model was developed based on 24 hours data collection. The model developed using Arena simulation replicates the actual ED's operations of a public hospital in Selangor, Malaysia. The OptQuest optimization in Arena is used to find the possible combinations of a number of resources that can minimize patients waiting time while increasing the number of patients served. The simulation model was modified for improvement based on results from OptQuest. The improvement model significantly improves ED's efficiency with an average of 32% reduction in average patients waiting times and 25% increase in the total number of patients served.

  7. Dynamic call center routing policies using call waiting and agent idle times

    NARCIS (Netherlands)

    Chan, W.; Koole, G.M.; L'Ecuyer, P.

    2014-01-01

    We study call routing policies for call centers with multiple call types and multiple agent groups. We introduce new weight-based routing policies where each pair (call type, agent group) is given a matching priority defined as an affine combination of the longest waiting time for that call type and

  8. Factors Associated with Waiting Time for Breast Cancer Treatment in a Teaching Hospital in Ghana

    Science.gov (United States)

    Dedey, Florence; Wu, Lily; Ayettey, Hannah; Sanuade, Olutobi A.; Akingbola, Titilola S.; Hewlett, Sandra A.; Tayo, Bamidele O.; Cole, Helen V.; de-Graft Aikins, Ama; Ogedegbe, Gbenga; Adanu, Richard

    2016-01-01

    Background: Breast cancer is the leading cause of cancer-related mortality among women in Ghana. Data are limited on the predictors of poor outcomes in breast cancer patients in low-income countries; however, prolonged waiting time has been implicated. Among breast cancer patients who received treatment at Korle Bu Teaching Hospital, this study…

  9. The unethical focus on access: a study of medical ethics and the waiting-time guarantee.

    Science.gov (United States)

    Karlberg, H I; Brinkmo, B-M

    2009-03-01

    All civilized societies favour ethical principles of equity. In healthcare, these principles generally focus on needs for medical care. Methods for establishing priorities among such needs are instrumental in this process. In this study, we analysed whether rules on access to healthcare, waiting-time guarantees, conflict with ethical principles of distributive justice. We interviewed directors, managers and other decision-makers of various healthcare providers of hospitals, primary care organizations and purchasing offices. We also conducted focus group interviews with professionals from a number of distinct medical areas. Our informants and their co-workers were reasonably familiar with the ethical platforms for priority-setting established by the Swedish parliament, giving the sickest patients complete priority. However, to satisfy the waiting-time guarantees, the informants often had to make priority decisions contrary to the ethical principles by favouring access before needs to keep waiting times within certain limits. The common opinion was that the waiting-time guarantee leads to crowding-out effects, overruling the ethical principles based on needs. For more than a decade, the interpretation in Sweden of the equitable principle based on medical needs has been distorted through political decisions, leading to healthcare providers giving priority to access rather than needs for care.

  10. Intake of wine, beer and spirits and waiting time to pregnancy.

    Science.gov (United States)

    Juhl, Mette; Olsen, Jørn; Andersen, Anne-Marie Nybo; Grønbaek, Morten

    2003-09-01

    A high intake of alcohol may prolong waiting time to pregnancy, whereas a moderate intake may have no or perhaps even a positive effect on fecundity. In previous studies on fecundity, different types of beverages have not been taken into consideration, although moderate wine drinkers appear to have fewer strokes, lung and digestive tract cancers, and overall mortality than both abstainers and moderate drinkers of beer or spirits. We examined the association between different types of alcoholic beverages and waiting time to pregnancy. Self-reported data were used for 29,844 pregnant women, recruited to the Danish National Birth Cohort in 1997-2000. Main outcome measures were odds ratios for a prolonged waiting time to pregnancy according to consumption of wine, beer and spirits. All levels of wine intake compared with non-wine drinking or with consumption of beer or spirits had subfecundity odds ratios between 0.7 and 0.9. No association was seen regarding beer drinking, while the association with spirits was J-shaped. Our findings suggest that wine drinkers have slightly shorter waiting times to pregnancy than both non-wine drinkers and consumers of other alcoholic beverages. Whether this is an effect of wine itself or the characteristics of the wine drinker is not known.

  11. Assessing and controlling the impact of hospital capacity planning on the waiting time

    NARCIS (Netherlands)

    Dellaert, N.; Çayiroglu, E.; Jeunet, J.

    2015-01-01

    In the literature, tactical plans of elective patients aim at increasing hospital efficiency through a better resource utilisation, although hospitals claim that patient satisfaction, usually measured by the waiting time, is also important. In this regard, the purpose of this paper is to show how

  12. Patients\\' response to waiting time in an out-patient pharmacy in ...

    African Journals Online (AJOL)

    Purpose: To identify the dispensing procedure at a pharmacy, investigate the possible operational problems that may lead to excessive patient waiting times as prescriptions are filled and to examine patient disposition to perceived delays at the pharmacy. Methods: The study was carried out in a 574-bed university teaching ...

  13. Assessing the impact of a waiting time survey on reducing waiting times in urban primary care clinics in Cape Town, South Africa

    Directory of Open Access Journals (Sweden)

    Johann Daniels

    2017-09-01

    Full Text Available A waiting time survey (WTS conducted in several clinics in Cape Town, South Africa provided recommendations on how to shorten waiting times (WT. A follow-up study was conducted to assess whether WT had reduced. Using a stratified sample of 22 clinics, a before and after study design assessed changes in WT. The WT was measured and perceptions of clinic managers were elicited, about the previous survey’s recommendations. The overall median WT decreased by 21 minutes (95%CI: 11.77- 30.23, a 28% decrease from the previous WTS. Although no specific factor was associated with decreases in WT, implementation of recommendations to reduce WT was 2.67 times (95%CI: 1.33-5.40 more likely amongst those who received written recommendations and 2.3 times (95%CI: 1.28- 4.19 more likely amongst managers with 5 or more years’ experience. The decrease in WT found demonstrates the utility of a WTS in busy urban clinics in developing country contexts. Experienced facility managers who timeously receive customised reports of their clinic’s performance are more likely to implement changes that positively impact on reducing WT.

  14. Time on wait lists for coronary bypass surgery in British Columbia, Canada, 1991 – 2000

    Directory of Open Access Journals (Sweden)

    Hayden Robert

    2005-03-01

    Full Text Available Abstract Background In British Columbia, Canada, all necessary medical services are funded publicly. Concerned with growing wait lists in the mid-1990s, the provincial government started providing extra funding for coronary artery bypass grafting (CABG operations annually. Although aimed at improving access, it is not known whether supplementary funding changed the time that patients spent on wait lists for CABG. We sought to determine whether the period of registration on wait lists had an effect on time to isolated CABG and whether the period effect was similar across priority groups. Methods Using records from a population-based registry, we studied the wait-list time before and after supplementary funding became available. We compared the number of weeks from registration to surgery for equal proportions of patients in synthetic cohorts defined by five registration periods in the 1990s. Results Overall, 9,231 patients spent a total of 137,126 person-weeks on the wait lists. The time to surgery increased by the middle of the decade, and decreased toward the end of the decade. Relative to the 1991–92 registration period, the conditional weekly probabilities of undergoing surgery were 30% lower among patients registered on the wait lists in 1995–96, hazard ratio (HR = 0.70 (0.65–0.76, and 23% lower in 1997–98 patients, HR = 0.77 (0.71–0.83, while there were no differences with 1999–2000 patients, HR = 0.94 (0.88–1.02, after adjusting for priority group at registration, comorbidity, age and sex. We found that the effect of registration period was different across priority groups. Conclusion Our results provide evidence that time to CABG shortened after supplementary funding was provided on an annual basis to tertiary care hospitals within a single publicly funded health system. One plausible explanation is that these hospitals had capacity to increase the number of operations. At the same time, the effect was not uniform across

  15. Wait time management strategies for total joint replacement surgery: sustainability and unintended consequences.

    Science.gov (United States)

    Pomey, Marie-Pascale; Clavel, Nathalie; Amar, Claudia; Sabogale-Olarte, Juan Carlos; Sanmartin, Claudia; De Coster, Carolyn; Noseworthy, Tom

    2017-09-07

    In Canada, long waiting times for core specialized services have consistently been identified as a key barrier to access. Governments and organizations have responded with strategies for better access management, notably for total joint replacement (TJR) of the hip and knee. While wait time management strategies (WTMS) are promising, the factors which influence their sustainable implementation at the organizational level are understudied. Consequently, this study examined organizational and systemic factors that made it possible to sustain waiting times for TJR within federally established limits and for at least 18 months or more. The research design is a multiple case study of WTMS implementation. Five cases were selected across five Canadian provinces. Three success levels were pre-defined: 1) the WTMS maintained compliance with requirements for more than 18 months; 2) the WTMS met requirements for 18 months but could not sustain the level thereafter; 3) the WTMS never met requirements. For each case, we collected documents and interviewed key informants. We analyzed systemic and organizational factors, with particular attention to governance and leadership, culture, resources, methods, and tools. We found that successful organizations had specific characteristics: 1) management of the whole care continuum, 2) strong clinical leadership; 3) dedicated committees to coordinate and sustain strategy; 4) a culture based on trust and innovation. All strategies led to relatively similar unintended consequences. The main negative consequence was an initial increase in waiting times for TJR and the main positive consequence was operational enhancement of other areas of specialization based on the TJR model. This study highlights important differences in factors which help to achieve and sustain waiting times. To be sustainable, a WTMS needs to generate greater synergies between contextual-level strategy (provincial or regional) and organizational objectives and

  16. Public involvement in the priority setting activities of a wait time management initiative: a qualitative case study.

    Science.gov (United States)

    Bruni, Rebecca A; Laupacis, Andreas; Levinson, Wendy; Martin, Douglas K

    2007-11-16

    As no health system can afford to provide all possible services and treatments for the people it serves, each system must set priorities. Priority setting decision makers are increasingly involving the public in policy making. This study focuses on public engagement in a key priority setting context that plagues every health system around the world: wait list management. The purpose of this study is to describe and evaluate priority setting for the Ontario Wait Time Strategy, with special attention to public engagement. This study was conducted at the Ontario Wait Time Strategy in Ontario, Canada which is part of a Federal-Territorial-Provincial initiative to improve access and reduce wait times in five areas: cancer, cardiac, sight restoration, joint replacements, and diagnostic imaging. There were two sources of data: (1) over 25 documents (e.g. strategic planning reports, public updates), and (2) 28 one-on-one interviews with informants (e.g. OWTS participants, MOHLTC representatives, clinicians, patient advocates). Analysis used a modified thematic technique in three phases: open coding, axial coding, and evaluation. The Ontario Wait Time Strategy partially meets the four conditions of 'accountability for reasonableness'. The public was not directly involved in the priority setting activities of the Ontario Wait Time Strategy. Study participants identified both benefits (supporting the initiative, experts of the lived experience, a publicly funded system and sustainability of the healthcare system) and concerns (personal biases, lack of interest to be involved, time constraints, and level of technicality) for public involvement in the Ontario Wait Time Strategy. Additionally, the participants identified concern for the consequences (sustainability, cannibalism, and a class system) resulting from the Ontario Wait Times Strategy. We described and evaluated a wait time management initiative (the Ontario Wait Time Strategy) with special attention to public

  17. Public involvement in the priority setting activities of a wait time management initiative: a qualitative case study

    Directory of Open Access Journals (Sweden)

    Laupacis Andreas

    2007-11-01

    Full Text Available Abstract Background As no health system can afford to provide all possible services and treatments for the people it serves, each system must set priorities. Priority setting decision makers are increasingly involving the public in policy making. This study focuses on public engagement in a key priority setting context that plagues every health system around the world: wait list management. The purpose of this study is to describe and evaluate priority setting for the Ontario Wait Time Strategy, with special attention to public engagement. Methods This study was conducted at the Ontario Wait Time Strategy in Ontario, Canada which is part of a Federal-Territorial-Provincial initiative to improve access and reduce wait times in five areas: cancer, cardiac, sight restoration, joint replacements, and diagnostic imaging. There were two sources of data: (1 over 25 documents (e.g. strategic planning reports, public updates, and (2 28 one-on-one interviews with informants (e.g. OWTS participants, MOHLTC representatives, clinicians, patient advocates. Analysis used a modified thematic technique in three phases: open coding, axial coding, and evaluation. Results The Ontario Wait Time Strategy partially meets the four conditions of 'accountability for reasonableness'. The public was not directly involved in the priority setting activities of the Ontario Wait Time Strategy. Study participants identified both benefits (supporting the initiative, experts of the lived experience, a publicly funded system and sustainability of the healthcare system and concerns (personal biases, lack of interest to be involved, time constraints, and level of technicality for public involvement in the Ontario Wait Time Strategy. Additionally, the participants identified concern for the consequences (sustainability, cannibalism, and a class system resulting from the Ontario Wait Times Strategy. Conclusion We described and evaluated a wait time management initiative (the Ontario

  18. Efficiency of performing pulmonary procedures in a shared endoscopy unit: procedure time, turnaround time, delays, and procedure waiting time.

    Science.gov (United States)

    Verma, Akash; Lee, Mui Yok; Wang, Chunhong; Hussein, Nurmalah B M; Selvi, Kalai; Tee, Augustine

    2014-04-01

    The purpose of this study was to assess the efficiency of performing pulmonary procedures in the endoscopy unit in a large teaching hospital. A prospective study from May 20 to July 19, 2013, was designed. The main outcome measures were procedure delays and their reasons, duration of procedural steps starting from patient's arrival to endoscopy unit, turnaround time, total case durations, and procedure wait time. A total of 65 procedures were observed. The most common procedure was BAL (61%) followed by TBLB (31%). Overall procedures for 35 (53.8%) of 65 patients were delayed by ≥ 30 minutes, 21/35 (60%) because of "spillover" of the gastrointestinal and surgical cases into the time block of pulmonary procedure. Time elapsed between end of pulmonary procedure and start of the next procedure was ≥ 30 minutes in 8/51 (16%) of cases. In 18/51 (35%) patients there was no next case in the room after completion of the pulmonary procedure. The average idle time of the room after the end of pulmonary procedure and start of next case or end of shift at 5:00 PM if no next case was 58 ± 53 minutes. In 17/51 (33%) patients the room's idle time was >60 minutes. A total of 52.3% of patients had the wait time >2 days and 11% had it ≥ 6 days, reason in 15/21 (71%) being unavailability of the slot. Most pulmonary procedures were delayed due to spillover of the gastrointestinal and surgical cases into the block time allocated to pulmonary procedures. The most common reason for difficulty encountered in scheduling the pulmonary procedure was slot unavailability. This caused increased procedure waiting time. The strategies to reduce procedure delays and turnaround times, along with improved scheduling methods, may have a favorable impact on the volume of procedures performed in the unit thereby optimizing the existing resources.

  19. Experience of being a low priority patient during waiting time at an emergency department.

    Science.gov (United States)

    Dahlen, Ingrid; Westin, Lars; Adolfsson, Annsofie

    2012-01-01

    Work in the emergency department is characterized by fast and efficient medical efforts to save lives, but can also involve a long waiting time for patients. Patients are given a priority rating upon their arrival in the clinic based on the seriousness of their problem, and nursing care for lower priority patients is given a lower prioritization. Regardless of their medical prioritization, all patients have a right to expect good nursing care while they are waiting. The purpose of this study was to illustrate the experience of the low prioritized patient during their waiting time in the emergency department. A phenomenological hermeneutic research method was used to analyze an interview transcript. Data collection consisted of narrative interviews. The interviewees were 14 patients who had waited more than three hours for surgical, orthopedic, or other medical care. The findings resulted in four different themes, ie, being dependent on care, being exposed, being vulnerable, and being secure. Lower priority patients are not paid as much attention by nursing staff. Patients reported feeling powerless, insulted, and humiliated when their care was delayed without their understanding what was happening to them. Not understanding results in exposure that violates self-esteem. The goal of the health care provider must be to minimize and prevent suffering, prevent feelings of vulnerability, and to create conditions for optimal patient well being.

  20. Universal algorithm of time sharing

    International Nuclear Information System (INIS)

    Silin, I.N.; Fedyun'kin, E.D.

    1979-01-01

    Timesharing system algorithm is proposed for the wide class of one- and multiprocessor computer configurations. Dynamical priority is the piece constant function of the channel characteristic and system time quantum. The interactive job quantum has variable length. Characteristic recurrent formula is received. The concept of the background job is introduced. Background job loads processor if high priority jobs are inactive. Background quality function is given on the base of the statistical data received in the timesharing process. Algorithm includes optimal trashing off procedure for the jobs replacements in the memory. Sharing of the system time in proportion to the external priorities is guaranteed for the all active enough computing channels (back-ground too). The fast answer is guaranteed for the interactive jobs, which use small time and memory. The external priority control is saved for the high level scheduler. The experience of the algorithm realization on the BESM-6 computer in JINR is discussed

  1. Application of Queueing Theory to the Analysis of Changes in Outpatients' Waiting Times in Hospitals Introducing EMR.

    Science.gov (United States)

    Cho, Kyoung Won; Kim, Seong Min; Chae, Young Moon; Song, Yong Uk

    2017-01-01

    This research used queueing theory to analyze changes in outpatients' waiting times before and after the introduction of Electronic Medical Record (EMR) systems. We focused on the exact drawing of two fundamental parameters for queueing analysis, arrival rate (λ) and service rate (µ), from digital data to apply queueing theory to the analysis of outpatients' waiting times. We used outpatients' reception times and consultation finish times to calculate the arrival and service rates, respectively. Using queueing theory, we could calculate waiting time excluding distorted values from the digital data and distortion factors, such as arrival before the hospital open time, which occurs frequently in the initial stage of a queueing system. We analyzed changes in outpatients' waiting times before and after the introduction of EMR using the methodology proposed in this paper, and found that the outpatients' waiting time decreases after the introduction of EMR. More specifically, the outpatients' waiting times in the target public hospitals have decreased by rates in the range between 44% and 78%. It is possible to analyze waiting times while minimizing input errors and limitations influencing consultation procedures if we use digital data and apply the queueing theory. Our results verify that the introduction of EMR contributes to the improvement of patient services by decreasing outpatients' waiting time, or by increasing efficiency. It is also expected that our methodology or its expansion could contribute to the improvement of hospital service by assisting the identification and resolution of bottlenecks in the outpatient consultation process.

  2. Toward systematic reviews to understand the determinants of wait time management success to help decision-makers and managers better manage wait times.

    Science.gov (United States)

    Pomey, Marie-Pascale; Forest, Pierre-Gerlier; Sanmartin, Claudia; Decoster, Carolyn; Clavel, Nathalie; Warren, Elaine; Drew, Madeleine; Noseworthy, Tom

    2013-06-06

    Long waits for core specialized services have consistently been identified as a key barrier to access. Governments and organizations at all levels have responded with strategies for better wait list management. While these initiatives are promising, insufficient attention has been paid to factors influencing the implementation and sustainability of wait time management strategies (WTMS) implemented at the organizational level. A systematic review was conducted using the main electronic databases, such as CINAHL, MEDLINE, and Cochrane Database of Systematic Reviews, to identify articles published between 1990 and 2011 on WTMS for scheduled care implemented at the organizational level or higher and on frameworks for analyzing factors influencing their success. Data was extracted on governance, culture, resources, and tools. We organized a workshop with Canadian healthcare policy-makers and managers to compare our initial findings with their experience. Our systematic review included 47 articles: 36 related to implementation and 11 to sustainability. From these, we identified a variety of WTMS initiated at the organizational level or higher, and within these, certain factors that were specific to either implementation or sustainability and others common to both. The main common factors influencing success at the contextual level were stakeholder engagement and strong funding, and at the organizational level, physician involvement, human resources capacity, and information management systems. Specific factors for successful implementation at the contextual level were consultation with front-line actors and common standards and guidelines, and at the organizational level, financial incentives and dedicated staffing. For sustainability, we found no new factors. The workshop participants identified the same major factors as found in the articles and added others, such as information sharing between physicians and managers. Factors related to implementation were studied

  3. Experience of being a low priority patient during waiting time at an emergency department

    Directory of Open Access Journals (Sweden)

    Adolfsson A

    2012-01-01

    Full Text Available Ingrid Dahlen1,2, Lars Westin1, Annsofie Adolfsson11School of Life Sciences, University of Skövde, Skövde, Sweden; 2Emergency Department, Skaraborg Hospital, Skövde, SwedenBackground: Work in the emergency department is characterized by fast and efficient medical efforts to save lives, but can also involve a long waiting time for patients. Patients are given a priority rating upon their arrival in the clinic based on the seriousness of their problem, and nursing care for lower priority patients is given a lower prioritization. Regardless of their medical prioritization, all patients have a right to expect good nursing care while they are waiting. The purpose of this study was to illustrate the experience of the low prioritized patient during their waiting time in the emergency department.Methods: A phenomenological hermeneutic research method was used to analyze an interview transcript. Data collection consisted of narrative interviews. The interviewees were 14 patients who had waited more than three hours for surgical, orthopedic, or other medical care.Results: The findings resulted in four different themes, ie, being dependent on care, being exposed, being vulnerable, and being secure. Lower priority patients are not paid as much attention by nursing staff. Patients reported feeling powerless, insulted, and humiliated when their care was delayed without their understanding what was happening to them. Not understanding results in exposure that violates self-esteem.Conclusion: The goal of the health care provider must be to minimize and prevent suffering, prevent feelings of vulnerability, and to create conditions for optimal patient well being.Keywords: emergency department, patients, waiting times, nursing staff

  4. The British Columbia Nephrologists’ Access Study (BCNAS) – a prospective, health services interventional study to develop waiting time benchmarks and reduce wait times for out-patient nephrology consultations

    Science.gov (United States)

    2013-01-01

    Background Early referral and management of high-risk chronic kidney disease may prevent or delay the need for dialysis. Automatic eGFR reporting has increased demand for out-patient nephrology consultations and in some cases, prolonged queues. In Canada, a national task force suggested the development of waiting time targets, which has not been done for nephrology. Methods We sought to describe waiting time for outpatient nephrology consultations in British Columbia (BC). Data collection occurred in 2 phases: 1) Baseline Description (Jan 18-28, 2010) and 2) Post Waiting Time Benchmark-Introduction (Jan 16-27, 2012). Waiting time was defined as the interval from receipt of referral letters to assessment. Using a modified Delphi process, Nephrologists and Family Physicians (FP) developed waiting time targets for commonly referred conditions through meetings and surveys. Rules were developed to weigh-in nephrologists’, FPs’, and patients’ perspectives in order to generate waiting time benchmarks. Targets consider comorbidities, eGFR, BP and albuminuria. Referred conditions were assigned a priority score between 1-4. BC nephrologists were encouraged to centrally triage referrals to see the first available nephrologist. Waiting time benchmarks were simultaneously introduced to guide patient scheduling. A post-intervention waiting time evaluation was then repeated. Results In 2010 and 2012, 43/52 (83%) and 46/57 (81%) of BC nephrologists participated. Waiting time decreased from 98(IQR44,157) to 64(IQR21,120) days from 2010 to 2012 (p = management associated with improved access to nephrologists in BC. Improvements in waiting time was most marked for the highest priority patients, which suggests that benchmarks had an influence on triaging behavior. Further research is needed to determine whether this effect is sustainable. PMID:23988113

  5. Decreasing laboratory turnaround time and patient wait time by implementing process improvement methodologies in an outpatient oncology infusion unit.

    Science.gov (United States)

    Gjolaj, Lauren N; Gari, Gloria A; Olier-Pino, Angela I; Garcia, Juan D; Fernandez, Gustavo L

    2014-11-01

    Prolonged patient wait times in the outpatient oncology infusion unit indicated a need to streamline phlebotomy processes by using existing resources to decrease laboratory turnaround time and improve patient wait time. Using the DMAIC (define, measure, analyze, improve, control) method, a project to streamline phlebotomy processes within the outpatient oncology infusion unit in an academic Comprehensive Cancer Center known as the Comprehensive Treatment Unit (CTU) was completed. Laboratory turnaround time for patients who needed same-day lab and CTU services and wait time for all CTU patients was tracked for 9 weeks. During the pilot, the wait time from arrival to CTU to sitting in treatment area decreased by 17% for all patients treated in the CTU during the pilot. A total of 528 patients were seen at the CTU phlebotomy location, representing 16% of the total patients who received treatment in the CTU, with a mean turnaround time of 24 minutes compared with a baseline turnaround time of 51 minutes. Streamlining workflows and placing a phlebotomy station inside of the CTU decreased laboratory turnaround times by 53% for patients requiring same day lab and CTU services. The success of the pilot project prompted the team to make the station a permanent fixture. Copyright © 2014 by American Society of Clinical Oncology.

  6. Effect of self-triage on waiting times at a walk-in sexual health clinic.

    Science.gov (United States)

    Hitchings, Samantha; Barter, Janet

    2009-10-01

    Lengthy waiting times can be a major problem in walk-in sexual health clinics. They are stressful for both patients and staff and may lead to clients with significant health issues leaving the department before being seen by a clinician. A self-triage system may help reduce waiting times and duplication of work, improve patient pathways and decrease wasted visits. This paper describes implementation of a self-triage system in two busy sexual and reproductive health clinics. Patients were asked to complete a self-assessment form on registration to determine the reason for attendance. This then enabled patients to be directed to the most appropriate specialist or clinical service. The benefits of this approach were determined by measuring patient waiting times, reduction in unnecessary specialist review together with patient acceptability as tested by a patient satisfaction survey. The ease of comprehension of the triage form was also assessed by an independent readers' panel. A total of 193 patients were recruited over a 4-month period from November 2004 to February 2005. Patients from the November and December clinics were assigned to the 'traditional treatment' arm, with patients at subsequent clinics being assigned to the 'self-triage' system. Waiting times were collected by the receptionist and clinic staff. Ninety six patients followed the traditional route, 97 the new self-triage system. Sixty-nine (35.8%) patients completed the satisfaction survey. The self-triage system significantly reduced waiting time from 40 (22, 60) to 23 (10, 40) minutes [results expressed as median (interquartile range)]. There was a non-significant reduction in the proportion of patients seeing two clinicians from 21% to 13% (p = 0.17). Satisfaction levels were not significantly altered (95% compared to 97% satisfied, p = 0.64). The readers' panel found the triage form both easy to understand and to complete. Self-triage can effectively reduce clinic waiting times and allow better

  7. Anomalous transport in fluid field with random waiting time depending on the preceding jump length

    International Nuclear Information System (INIS)

    Zhang Hong; Li Guo-Hua

    2016-01-01

    Anomalous (or non-Fickian) transport behaviors of particles have been widely observed in complex porous media. To capture the energy-dependent characteristics of non-Fickian transport of a particle in flow fields, in the present paper a generalized continuous time random walk model whose waiting time probability distribution depends on the preceding jump length is introduced, and the corresponding master equation in Fourier–Laplace space for the distribution of particles is derived. As examples, two generalized advection-dispersion equations for Gaussian distribution and lévy flight with the probability density function of waiting time being quadratic dependent on the preceding jump length are obtained by applying the derived master equation. (paper)

  8. Anomalous transport in fluid field with random waiting time depending on the preceding jump length

    Science.gov (United States)

    Zhang, Hong; Li, Guo-Hua

    2016-11-01

    Anomalous (or non-Fickian) transport behaviors of particles have been widely observed in complex porous media. To capture the energy-dependent characteristics of non-Fickian transport of a particle in flow fields, in the present paper a generalized continuous time random walk model whose waiting time probability distribution depends on the preceding jump length is introduced, and the corresponding master equation in Fourier-Laplace space for the distribution of particles is derived. As examples, two generalized advection-dispersion equations for Gaussian distribution and lévy flight with the probability density function of waiting time being quadratic dependent on the preceding jump length are obtained by applying the derived master equation. Project supported by the Foundation for Young Key Teachers of Chengdu University of Technology, China (Grant No. KYGG201414) and the Opening Foundation of Geomathematics Key Laboratory of Sichuan Province, China (Grant No. scsxdz2013009).

  9. Prescription duration and treatment episodes in oral glucocorticoid users: application of the parametric waiting time distribution

    DEFF Research Database (Denmark)

    Laugesen, Kristina; Støvring, Henrik; Hallas, Jesper

    2017-01-01

    for oral glucocorticoids and to describe continuous treatment episodes using the parametric waiting time distribution. Methods: We used Danish nationwide registries to identify all prescriptions for oral glucocorticoids during 1996-2014. We applied the parametric waiting time distribution to estimate...... duration of individual prescriptions each year by estimating the 80th, 90th, 95th and 99th percentiles for the interarrival distribution. These corresponded to the time since last prescription during which 80%, 90%, 95% and 99% of users presented a new prescription for redemption. We used the Kaplan...... of the interarrival distribution to apply as prescription duration has an impact on the level of misclassification. Use of the 80th percentile provides a measure of drug exposure that is specific, while the 99th percentile provides a sensitive measure....

  10. Continuous time random walk model with asymptotical probability density of waiting times via inverse Mittag-Leffler function

    Science.gov (United States)

    Liang, Yingjie; Chen, Wen

    2018-04-01

    The mean squared displacement (MSD) of the traditional ultraslow diffusion is a logarithmic function of time. Recently, the continuous time random walk model is employed to characterize this ultraslow diffusion dynamics by connecting the heavy-tailed logarithmic function and its variation as the asymptotical waiting time density. In this study we investigate the limiting waiting time density of a general ultraslow diffusion model via the inverse Mittag-Leffler function, whose special case includes the traditional logarithmic ultraslow diffusion model. The MSD of the general ultraslow diffusion model is analytically derived as an inverse Mittag-Leffler function, and is observed to increase even more slowly than that of the logarithmic function model. The occurrence of very long waiting time in the case of the inverse Mittag-Leffler function has the largest probability compared with the power law model and the logarithmic function model. The Monte Carlo simulations of one dimensional sample path of a single particle are also performed. The results show that the inverse Mittag-Leffler waiting time density is effective in depicting the general ultraslow random motion.

  11. A modelling framework for mitigating customers' waiting time at a vehicle inspection centre

    Science.gov (United States)

    Ahmad, Norazura; Abidin, Norhaslinda Zainal; Ilyas, Khibtiyah; Abduljabbar, Waleed Khalid

    2017-11-01

    In Malaysia, an agency that is entrusted by the Government to perform mandatory vehicle inspection for public, commercial and private vehicles, receive many customers daily. Often complaints of problems received from the customers are associated with waiting time that leads to lost of business and dissatisfied customers. To address this issue, we propose a framework for modelling a vehicle inspection system using an integration of simulation and optimization approaches. The strengths of simulation and optimization are reviewed briefly that is hoped to reveal the synergy between the established methods in determining an appropriate customer's waiting time for inspection at a vehicle inspection centre. Relevant concepts and preliminary results are also presented and discussed in this paper.

  12. [Patients' satisfaction and waiting time in oncology day care centers in Champagne-Ardenne].

    Science.gov (United States)

    Debreuve-Theresette, A; Jovenin, N; Stona, A C; Kraïem-Leleu, M; Burde, F; Parent, D; Hettler, D; Rey, J B

    2015-12-01

    Quality of life of patients suffering from cancer may be influenced by the way healthcare is organized and by patient experiences. Nowadays, chemotherapy is often provided in day care centers. This study aimed to assess patient waiting time and satisfaction in oncology day care centers in Champagne-Ardenne, France. This cross-sectional survey involved all patients receiving ambulatory chemotherapy during a one-week period in day care centers of Champagne-Ardenne public and private healthcare institutions participating in the study. Sociodemographic, medical and outpatient data were collected. Patient satisfaction was measured using the Out-Patsat35 questionnaire. Eleven (out of 16) oncology day care centers and 441 patients participated in the study. Most of the patients were women (n=252, 57.1%) and the mean age was 61±12 years. The mean satisfaction score was 82±14 (out of 100) and the mean waiting time between the assigned appointment time and administration of chemotherapy was 97±60 min. This study has shown that waiting times are important. However, patients are satisfied with the healthcare organization, especially regarding nursing support. Early preparation of chemotherapy could improve these parameters. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  13. Waiting-time distributions of magnetic discontinuities: Clustering or Poisson process?

    International Nuclear Information System (INIS)

    Greco, A.; Matthaeus, W. H.; Servidio, S.; Dmitruk, P.

    2009-01-01

    Using solar wind data from the Advanced Composition Explorer spacecraft, with the support of Hall magnetohydrodynamic simulations, the waiting-time distributions of magnetic discontinuities have been analyzed. A possible phenomenon of clusterization of these discontinuities is studied in detail. We perform a local Poisson's analysis in order to establish if these intermittent events are randomly distributed or not. Possible implications about the nature of solar wind discontinuities are discussed.

  14. Analyzing patient's waiting time in emergency & trauma department in public hospital - A case study

    Science.gov (United States)

    Roslan, Shazwa; Tahir, Herniza Md; Nordin, Noraimi Azlin Mohd; Zaharudin, Zati Aqmar

    2014-09-01

    Emergency and Trauma Department (ETD) is an important element for a hospital. It provides medical service, which operates 24 hours a day in most hospitals. However overcrowding is not exclusion for ETD. Overflowing occurs due to affordable services provided by public hospitals, since it is funded by the government. It is reported that a patient attending ETD must be treated within 90 minutes, in accordance to achieve the Key Performance Indicator (KPI). However, due to overcrowd situations, most patients have to wait longer than the KPI standard. In this paper, patient's average waiting time is analyzed. Using Chi-Square Test of Goodness, patient's inter arrival per hour is also investigated. As conclusion, Monday until Wednesday was identified as the days that exceed the KPI standard while Chi-Square Test of Goodness showed that the patient's inter arrival is independent and random.

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

    DEFF Research Database (Denmark)

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

    2018-01-01

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

  16. Transition in the waiting-time distribution of price-change events in a global socioeconomic system

    Science.gov (United States)

    Zhao, Guannan; McDonald, Mark; Fenn, Dan; Williams, Stacy; Johnson, Nicholas; Johnson, Neil F.

    2013-12-01

    The goal of developing a firmer theoretical understanding of inhomogeneous temporal processes-in particular, the waiting times in some collective dynamical system-is attracting significant interest among physicists. Quantifying the deviations between the waiting-time distribution and the distribution generated by a random process may help unravel the feedback mechanisms that drive the underlying dynamics. We analyze the waiting-time distributions of high-frequency foreign exchange data for the best executable bid-ask prices across all major currencies. We find that the lognormal distribution yields a good overall fit for the waiting-time distribution between currency rate changes if both short and long waiting times are included. If we restrict our study to long waiting times, each currency pair’s distribution is consistent with a power-law tail with exponent near to 3.5. However, for short waiting times, the overall distribution resembles one generated by an archetypal complex systems model in which boundedly rational agents compete for limited resources. Our findings suggest that a gradual transition arises in trading behavior between a fast regime in which traders act in a boundedly rational way and a slower one in which traders’ decisions are driven by generic feedback mechanisms across multiple timescales and hence produce similar power-law tails irrespective of currency type.

  17. A Cross-Sectional Survey of Population-Wide Wait Times for Patients Seeking Medical vs. Cosmetic Dermatologic Care.

    Directory of Open Access Journals (Sweden)

    Geeta Yadav

    Full Text Available Though previous work has examined some aspects of the dermatology workforce shortage and access to dermatologic care, little research has addressed the effect of rising interest in cosmetic procedures on access to medical dermatologic care. Our objective was to determine the wait times for Urgent and Non-Urgent medical dermatologic care and Cosmetic dermatology services at a population level and to examine whether wait times for medical care are affected by offering cosmetic services.A population-wide survey of dermatology practices using simulated calls asking for the earliest appointment for a Non-Urgent, Urgent and Cosmetic service.Response rates were greater than 89% for all types of care. Wait times across all types of care were significantly different from each other (all P < 0.05. Cosmetic care was associated with the shortest wait times (3.0 weeks; Interquartile Range (IQR = 0.4-3.4, followed by Urgent care (9.0 weeks; IQR = 2.1-12.9, then Non-Urgent Care (12.7 weeks; IQR = 4.4-16.4. Wait times for practices offering only Urgent care were not different from practices offering both Urgent and Cosmetic care (10.3 vs. 7.0 weeks.Longer wait times and greater variation for Urgent and Non-Urgent dermatologic care and shorter wait times and less variation for Cosmetic care. Wait times were significantly longer in regions with lower dermatologist density. Provision of Cosmetic services did not increase wait times for Urgent care. These findings suggest an overall dermatology workforce shortage and a need for a more streamlined referral system for dermatologic care.

  18. A Cross-Sectional Survey of Population-Wide Wait Times for Patients Seeking Medical vs. Cosmetic Dermatologic Care.

    Science.gov (United States)

    Yadav, Geeta; Goldberg, Hanna R; Barense, Morgan D; Bell, Chaim M

    2016-01-01

    Though previous work has examined some aspects of the dermatology workforce shortage and access to dermatologic care, little research has addressed the effect of rising interest in cosmetic procedures on access to medical dermatologic care. Our objective was to determine the wait times for Urgent and Non-Urgent medical dermatologic care and Cosmetic dermatology services at a population level and to examine whether wait times for medical care are affected by offering cosmetic services. A population-wide survey of dermatology practices using simulated calls asking for the earliest appointment for a Non-Urgent, Urgent and Cosmetic service. Response rates were greater than 89% for all types of care. Wait times across all types of care were significantly different from each other (all P Cosmetic care was associated with the shortest wait times (3.0 weeks; Interquartile Range (IQR) = 0.4-3.4), followed by Urgent care (9.0 weeks; IQR = 2.1-12.9), then Non-Urgent Care (12.7 weeks; IQR = 4.4-16.4). Wait times for practices offering only Urgent care were not different from practices offering both Urgent and Cosmetic care (10.3 vs. 7.0 weeks). Longer wait times and greater variation for Urgent and Non-Urgent dermatologic care and shorter wait times and less variation for Cosmetic care. Wait times were significantly longer in regions with lower dermatologist density. Provision of Cosmetic services did not increase wait times for Urgent care. These findings suggest an overall dermatology workforce shortage and a need for a more streamlined referral system for dermatologic care.

  19. The importance of patient expectations as a determinant of satisfaction with waiting times for hip and knee replacement surgery.

    Science.gov (United States)

    Conner-Spady, Barbara L; Sanmartin, Claudia; Johnston, Geoffrey H; McGurran, John J; Kehler, Melissa; Noseworthy, Tom W

    2011-08-01

    The disconfirmation model hypothesizes that satisfaction is a function of a perceived discrepancy from an initial expectation. Our objectives were: (1) to test the disconfirmation model as it applies to patient satisfaction with waiting time (WT) and (2) to build an explanatory model of the determinants of satisfaction with WT for hip and knee replacement. We mailed 1000 questionnaires to 2 random samples: patients waiting or those who had received a joint replacement within the preceding 3-12 months. We used ordinal logistic regression analysis to build an explanatory model of the determinants of satisfaction. Of the 1330 returned surveys, 1240 contained patient satisfaction data. The sample was 57% female; mean age was 70 years (SD 11). Consistent with the disconfirmation model, when their WTs were longer than expected, both waiting (OR 5.77, 95% CI 3.57-9.32) and post-surgery patients (OR 6.57, 95% CI 4.21-10.26) had greater odds of dissatisfaction, adjusting for the other variables in the model. Compared to those who waited 3 months or less, post-surgery patients who waited 6 to 12 months (OR 2.59, 95% CI 1.27-5.27) and over 12 months (OR 3.30, 95% CI 1.65-6.58) had greater odds of being dissatisfied with their waiting time. Patients who felt they were treated unfairly had greater odds of being dissatisfied (OR 4.74, 95% CI 2.60-8.62). In patients on waiting lists and post-surgery for hip and knee replacement, satisfaction with waiting times is related to fulfillment of expectations about waiting, as well as a perception of fairness. Measures to modify expectations and increase perceived fairness, such as informing patients of a realistic WT and communication during the waiting period, may increase satisfaction with WTs. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  20. Reduction of admit wait times: the effect of a leadership-based program.

    Science.gov (United States)

    Patel, Pankaj B; Combs, Mary A; Vinson, David R

    2014-03-01

    Prolonged admit wait times in the emergency department (ED) for patients who require hospitalization lead to increased boarding time in the ED, a significant cause of ED congestion. This is associated with decreased quality of care, higher morbidity and mortality, decreased patient satisfaction, increased costs for care, ambulance diversion, higher numbers of patients who leave without being seen (LWBS), and delayed care with longer lengths of stay (LOS) for other ED patients. The objective was to assess the effect of a leadership-based program to expedite hospital admissions from the ED. This before-and-after observational study was undertaken from 2006 through 2011 at one community hospital ED. A team of ED and hospital leaders implemented a program to reduce admit wait times, using a computerized hospital-wide tracking system to monitor inpatient and ED bed status. The team collaboratively and consistently moved ED patients to their inpatient beds within an established goal of 60 minutes after an admission decision was reached. Top leadership actively intervened in real time by contacting staff whenever delays occurred to expedite immediate solutions to achieve the 60-minute goal. The primary outcome measures were the percentage of ED patients who were admitted to inpatient beds within 60 minutes from the time the beds were requested and ED boarding time. LOS, patient satisfaction, LWBS rate, and ambulance diversion hours were also measured. After ED census, hospital admission rates, and ED bed capacity were controlled for using a multivariable linear regression analysis, the admit wait time reduction program contributed to an increase in patients being admitted to the hospital within 60 minutes by 16 percentage points (95% confidence intervals [CI] = 10 to 22 points; p leadership-based program to reduce admit wait times and boarding times was associated with a significant increase in the percentage of patients admitted to the hospital within 60 minutes and a

  1. A model to prioritize access to elective surgery on the basis of clinical urgency and waiting time

    Directory of Open Access Journals (Sweden)

    Santori Gregorio

    2009-01-01

    Full Text Available Abstract Background Prioritization of waiting lists for elective surgery represents a major issue in public systems in view of the fact that patients often suffer from consequences of long waiting times. In addition, administrative and standardized data on waiting lists are generally lacking in Italy, where no detailed national reports are available. This is true although since 2002 the National Government has defined implicit Urgency-Related Groups (URGs associated with Maximum Time Before Treatment (MTBT, similar to the Australian classification. The aim of this paper is to propose a model to manage waiting lists and prioritize admissions to elective surgery. Methods In 2001, the Italian Ministry of Health funded the Surgical Waiting List Info System (SWALIS project, with the aim of experimenting solutions for managing elective surgery waiting lists. The project was split into two phases. In the first project phase, ten surgical units in the largest hospital of the Liguria Region were involved in the design of a pre-admission process model. The model was embedded in a Web based software, adopting Italian URGs with minor modifications. The SWALIS pre-admission process was based on the following steps: 1 urgency assessment into URGs; 2 correspondent assignment of a pre-set MTBT; 3 real time prioritization of every referral on the list, according to urgency and waiting time. In the second project phase a prospective descriptive study was performed, when a single general surgery unit was selected as the deployment and test bed, managing all registrations from March 2004 to March 2007 (1809 ordinary and 597 day cases. From August 2005, once the SWALIS model had been modified, waiting lists were monitored and analyzed, measuring the impact of the model by a set of performance indexes (average waiting time, length of the waiting list and Appropriate Performance Index (API. Results The SWALIS pre-admission model was used for all registrations in the

  2. Transport properties of the continuous-time random walk with a long-tailed waiting-time density

    International Nuclear Information System (INIS)

    Weissman, H.; Havlin, S.; Weiss, G.H.

    1989-01-01

    The authors derive asymptotic properties of the propagator p(r, t) of a continuous-time random walk (CTRW) in which the waiting time density has the asymptotic form ψ(t) ∼ T α /t α+1 when t >> T and 0 = ∫ 0 ∞ τψ(τ)dτ is finite. One is that the asymptotic behavior of p(0, t) is demonstrated by the waiting time at the origin rather than by the dimension. The second difference is that in the presence of a field p(r, t) no longer remains symmetric around a moving peak. Rather, it is shown that the peak of this probability always occurs at r = 0, and the effect of the field is to break the symmetry that occurs when < ∞. Finally, they calculate similar properties, although in not such great detail, for the case in which the single-step jump probabilities themselves have an infinite mean

  3. Hospital Capacity, Waiting Times and Sick Leave Duration - an Empirical Analysis of a Norwegian Health Policy Reform

    OpenAIRE

    Aakvik, Arild; Holmås, Tor Helge; Kjerstad, Egil

    2012-01-01

    A health policy reform aiming to reduce hospital waiting times and sickness absences, the Faster Return to Work (FRW) scheme, is evaluated by creating treatment and control groups to facilitate causal interpretations of the empirical results. We use a unique dataset on individuals where we match hospital data with social security data and socio-economic characteristics. The main idea behind the reform is that long waiting times for hospital treatment lead to unnecessarily long periods of sick...

  4. A Study to Determine Patient Waiting Time at the Outpatient Pharmacy at Wilford Hall USAF Medical Center

    Science.gov (United States)

    1988-06-01

    at Wilford Hall USAF Medical Center significantly reduced the patient wait time at the main outpatient pharmacy. Satellite pharmacies have been ).’l...PRESENTING TO WINDOW 1, 19 MAR 88. 47 C:. A’.’E-:A: -ESCRIRTIONS PER PATIENT ...........48 H. WILFORD HALL MEDICAL CENTER OUTPATIENT QUESTIONNAIRE...that wait times at tne outpatient pharmacy were excessive. It was this concern that motivated the Medical Center Administrator to request that patient

  5. Waiting time distribution for the first conception leading to a live birth

    International Nuclear Information System (INIS)

    Shrestha, G.; Biswas, S.

    1985-01-01

    An attempt has been made in this paper to obtain probability model describing the distribution of the waiting time from marriage to first conception based on the data from marriage to first live birth. The speciality of this present approach lies in assuming the marital exposure to be finite which was assumed to be infinite by most of the earlier investigators for mathematical simplicity. Illustration of the applicability of the model on the data pertaining to first order of conception and monthly probability of conception for women married at different age groups have been illustrated in this paper. (author)

  6. Ethnographies of Waiting

    DEFF Research Database (Denmark)

    Janeja, Manpreet Kaur; Bandak, Andreas

    We all wait – in traffic jams, passport offices, school meal queues, for better weather, an end to fighting, peace. Time spent waiting produces hope, boredom, anxiety, doubt, or uncertainty. Ethnographies of Waiting explores the social phenomenon of waiting and its centrality in human society...... worth the wait?" Waiting thus conceived is intrinsic to the ethnographic method at the heart of the anthropological enterprise. Featuring detailed ethnographies from Japan, Georgia, England, Ghana, Norway, Russia and the United States, a Foreword by Craig Jeffrey and an Afterword by Ghassan Hage...

  7. A Cross-Sectional Survey of Population-Wide Wait Times for Patients Seeking Medical vs. Cosmetic Dermatologic Care

    Science.gov (United States)

    Yadav, Geeta; Goldberg, Hanna R.; Barense, Morgan D.; Bell, Chaim M.

    2016-01-01

    Background Though previous work has examined some aspects of the dermatology workforce shortage and access to dermatologic care, little research has addressed the effect of rising interest in cosmetic procedures on access to medical dermatologic care. Our objective was to determine the wait times for Urgent and Non-Urgent medical dermatologic care and Cosmetic dermatology services at a population level and to examine whether wait times for medical care are affected by offering cosmetic services. Methods A population-wide survey of dermatology practices using simulated calls asking for the earliest appointment for a Non-Urgent, Urgent and Cosmetic service. Results Response rates were greater than 89% for all types of care. Wait times across all types of care were significantly different from each other (all P dermatologic care and shorter wait times and less variation for Cosmetic care. Wait times were significantly longer in regions with lower dermatologist density. Provision of Cosmetic services did not increase wait times for Urgent care. These findings suggest an overall dermatology workforce shortage and a need for a more streamlined referral system for dermatologic care. PMID:27632206

  8. Public reporting on quality, waiting times and patient experience in 11 high-income countries.

    Science.gov (United States)

    Rechel, Bernd; McKee, Martin; Haas, Marion; Marchildon, Gregory P; Bousquet, Frederic; Blümel, Miriam; Geissler, Alexander; van Ginneken, Ewout; Ashton, Toni; Saunes, Ingrid Sperre; Anell, Anders; Quentin, Wilm; Saltman, Richard; Culler, Steven; Barnes, Andrew; Palm, Willy; Nolte, Ellen

    2016-04-01

    This article maps current approaches to public reporting on waiting times, patient experience and aggregate measures of quality and safety in 11 high-income countries (Australia, Canada, England, France, Germany, Netherlands, New Zealand, Norway, Sweden, Switzerland and the United States). Using a questionnaire-based survey of key national informants, we found that the data most commonly made available to the public are on waiting times for hospital treatment, being reported for major hospitals in seven countries. Information on patient experience at hospital level is also made available in many countries, but it is not generally available in respect of primary care services. Only one of the 11 countries (England) publishes composite measures of overall quality and safety of care that allow the ranking of providers of hospital care. Similarly, the publication of information on outcomes of individual physicians remains rare. We conclude that public reporting of aggregate measures of quality and safety, as well as of outcomes of individual physicians, remain relatively uncommon. This is likely to be due to both unresolved methodological and ethical problems and concerns that public reporting may lead to unintended consequences. Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  9. Predictive event modelling in multicenter clinical trials with waiting time to response.

    Science.gov (United States)

    Anisimov, Vladimir V

    2011-01-01

    A new analytic statistical technique for predictive event modeling in ongoing multicenter clinical trials with waiting time to response is developed. It allows for the predictive mean and predictive bounds for the number of events to be constructed over time, accounting for the newly recruited patients and patients already at risk in the trial, and for different recruitment scenarios. For modeling patient recruitment, an advanced Poisson-gamma model is used, which accounts for the variation in recruitment over time, the variation in recruitment rates between different centers and the opening or closing of some centers in the future. A few models for event appearance allowing for 'recurrence', 'death' and 'lost-to-follow-up' events and using finite Markov chains in continuous time are considered. To predict the number of future events over time for an ongoing trial at some interim time, the parameters of the recruitment and event models are estimated using current data and then the predictive recruitment rates in each center are adjusted using individual data and Bayesian re-estimation. For a typical scenario (continue to recruit during some time interval, then stop recruitment and wait until a particular number of events happens), the closed-form expressions for the predictive mean and predictive bounds of the number of events at any future time point are derived under the assumptions of Markovian behavior of the event progression. The technique is efficiently applied to modeling different scenarios for some ongoing oncology trials. Case studies are considered. Copyright © 2011 John Wiley & Sons, Ltd.

  10. Gender and socioeconomic status as determinants of waiting time for inpatient surgery in a system with implicit queue management.

    Science.gov (United States)

    Arnesen, Kjell E; Erikssen, Jan; Stavem, Knut

    2002-12-01

    In a system with implicit queue management, to examine gender and socioeconomic status as determinants of waiting time for inpatient surgery, after adjusting for other potential predictors. A cohort of 452 subjects was examined in outpatient clinics of a general hospital and referred to inpatient surgery. They were followed until scheduled hospital admission (n=396) or until the requested procedure no longer was relevant (n=56). We compared waiting time between groups from referral date until hospital admission, using Kaplan-Meier estimates of waiting times and log rank test. A Cox proportional hazards model was used for assessing the risk ratio (RR) of hospital admission for scheduled surgery. Gender and socioeconomic status could not explain variations in waiting time. However, patients with suspected/verified neoplastic disease or a risk of serious deterioration without treatment had markedly shorter waiting times than the reference groups, with adjusted RR (95% confidence intervals (95%CI)) of time to receiving in-patient surgery of 2.3 (1.7-3.0) and 2.0 (1.3-3.0), respectively. Being on sick leave was associated with shorter waiting time, adjusted RR of 1.7 (1.2-2.5). Referrals from within the hospital or other hospitals had also shorter waiting times than referrals from primary health care physicians, adjusted RR=1.4 (1.1-1.8). There was no evidence of bias against women or people in lower socioeconomic classes in this implicit queue management system. However, patients' access to inpatient surgery was associated with malignancy, prognosis, sick leave status, physician experience, referral pattern and the major diagnosis category.

  11. Solving no-wait two-stage flexible flow shop scheduling problem with unrelated parallel machines and rework time by the adjusted discrete Multi Objective Invasive Weed Optimization and fuzzy dominance approach

    Energy Technology Data Exchange (ETDEWEB)

    Jafarzadeh, Hassan; Moradinasab, Nazanin; Gerami, Ali

    2017-07-01

    Adjusted discrete Multi-Objective Invasive Weed Optimization (DMOIWO) algorithm, which uses fuzzy dominant approach for ordering, has been proposed to solve No-wait two-stage flexible flow shop scheduling problem. Design/methodology/approach: No-wait two-stage flexible flow shop scheduling problem by considering sequence-dependent setup times and probable rework in both stations, different ready times for all jobs and rework times for both stations as well as unrelated parallel machines with regards to the simultaneous minimization of maximum job completion time and average latency functions have been investigated in a multi-objective manner. In this study, the parameter setting has been carried out using Taguchi Method based on the quality indicator for beater performance of the algorithm. Findings: The results of this algorithm have been compared with those of conventional, multi-objective algorithms to show the better performance of the proposed algorithm. The results clearly indicated the greater performance of the proposed algorithm. Originality/value: This study provides an efficient method for solving multi objective no-wait two-stage flexible flow shop scheduling problem by considering sequence-dependent setup times, probable rework in both stations, different ready times for all jobs, rework times for both stations and unrelated parallel machines which are the real constraints.

  12. Solving no-wait two-stage flexible flow shop scheduling problem with unrelated parallel machines and rework time by the adjusted discrete Multi Objective Invasive Weed Optimization and fuzzy dominance approach

    International Nuclear Information System (INIS)

    Jafarzadeh, Hassan; Moradinasab, Nazanin; Gerami, Ali

    2017-01-01

    Adjusted discrete Multi-Objective Invasive Weed Optimization (DMOIWO) algorithm, which uses fuzzy dominant approach for ordering, has been proposed to solve No-wait two-stage flexible flow shop scheduling problem. Design/methodology/approach: No-wait two-stage flexible flow shop scheduling problem by considering sequence-dependent setup times and probable rework in both stations, different ready times for all jobs and rework times for both stations as well as unrelated parallel machines with regards to the simultaneous minimization of maximum job completion time and average latency functions have been investigated in a multi-objective manner. In this study, the parameter setting has been carried out using Taguchi Method based on the quality indicator for beater performance of the algorithm. Findings: The results of this algorithm have been compared with those of conventional, multi-objective algorithms to show the better performance of the proposed algorithm. The results clearly indicated the greater performance of the proposed algorithm. Originality/value: This study provides an efficient method for solving multi objective no-wait two-stage flexible flow shop scheduling problem by considering sequence-dependent setup times, probable rework in both stations, different ready times for all jobs, rework times for both stations and unrelated parallel machines which are the real constraints.

  13. Waiting times before dental care under general anesthesia in children with special needs in the Children's Hospital of Casablanca.

    Science.gov (United States)

    Badre, Bouchra; Serhier, Zineb; El Arabi, Samira

    2014-01-01

    Oral diseases may have an impact on quality of children's life. The presence of severe disability requires the use of care under general anesthesia (GA). However, because of the limited number of qualified health personnel, waiting time before intervention can be long. To evaluate the waiting time before dental care under general anesthesia for children with special needs in Morocco. A retrospective cohort study was carried out in pediatric dentistry unit of the University Hospital of Casablanca. Data were collected from records of patients seen for the first time between 2006 and 2011. The waiting time was defined as the time between the date of the first consultation and intervention date. 127 children received dental care under general anesthesia, 57.5% were male and the average age was 9.2 (SD = 3.4). Decay was the most frequent reason for consultation (48%), followed by pain (32%). The average waiting time was 7.6 months (SD = 4.2 months). The average number of acts performed per patient was 13.5. Waiting times were long, it is necessary to take measures to reduce delays and improve access to oral health care for this special population.

  14. Emergency Department Waiting Times (EDWaT): A Patient Flow Management and Quality of Care Rating mHealth Application.

    Science.gov (United States)

    Househ, Mowafa; Yunus, Faisel

    2014-01-01

    Saudi hospital emergency departments (ED) have suffered from long waiting times, which have led to a delay in emergency patient care. The increase in the population of Saudi Arabia is likely to further stretch the healthcare services due to overcrowding leading to decreased healthcare quality, long patient waits, patient dissatisfaction, ambulance diversions, decreased physician productivity, and increased frustration among medical staff. This will ultimately put patients at risk for poor health outcomes. Time is of the essence in emergencies and to get to an ED that has the shortest waiting time can mean life or death for a patient, especially in cases of stroke and myocardial infarction. In this paper, we present our work on the development of a mHealth Application - EDWaT - that will: provide patient flow information to the emergency medical services staff, help in quick routing of patients to the nearest hospital, and provide an opportunity for patients to review and rate the quality of care received at an ED, which will then be forwarded to ED services administrators. The quality ratings will help patients to choose between two EDs with the same waiting time and distance from their location. We anticipate that the use of EDWaT will help improve ED wait times and the quality of care provision in Saudi hospitals EDs.

  15. Wait Time Management Strategies for Scheduled Care: What Makes Them Succeed?

    Science.gov (United States)

    Pomey, Marie-Pascale; Forest, Pierre-Gerlier; Sanmartin, Claudia; De Coster, Carolyn; Drew, Madeleine

    2010-01-01

    Objectives: To assess experts' perceptions of the contextual and local factors that promote or inhibit the implementation of waiting time management strategies (WTMS) in Canadian healthcare organizations. Methods: We conducted 16 semi-structured interviews and one focus group with individuals involved in WTMS at the federal, provincial or organizational level. Results: The most frequently cited local factor was physicians' participation. Physicians' leadership made the greatest difference in bringing resistant physicians on board. To be effective, however, local leadership had to be supported by senior management. Alignment of financial incentives between the contextual and local levels was also frequently cited, and interviewees stressed the importance of tools used to design, monitor, evaluate and prioritize WTMS. Conclusions: Finding the right balance between supportive resources and tools and an effective management system is a tough challenge. But achieving this balance will help reconcile contradictions between top-down and bottom-up WTMS. PMID:21286269

  16. Lean-driven improvements slash wait times, drive up patient satisfaction scores.

    Science.gov (United States)

    2012-07-01

    Administrators at LifePoint Hospitals, based in Brentwood, TN, used lean manufacturing techniques to slash wait times by as much as 30 minutes and achieve double-digit increases in patient satisfaction scores in the EDs at three hospitals. In each case, front-line workers took the lead on identifying opportunities for improvement and redesigning the patient-flow process. As a result of the new efficiencies, patient volume is up by about 25% at all three hospitals. At each hospital, the improvement process began with Kaizen, a lean process that involves bringing personnel together to flow-chart the current system, identify problem areas, and redesign the process. Improvement teams found big opportunities for improvement at the front end of the flow process. Key to the approach was having a plan up front to deal with non-compliance. To sustain improvements, administrators gather and disseminate key metrics on a daily basis.

  17. Wait time management strategies for scheduled care: what makes them succeed?

    Science.gov (United States)

    Pomey, Marie-Pascale; Forest, Pierre-Gerlier; Sanmartin, Claudia; De Coster, Carolyn; Drew, Madeleine

    2010-02-01

    To assess experts' perceptions of the contextual and local factors that promote or inhibit the implementation of waiting time management strategies (WTMS) in Canadian healthcare organizations. We conducted 16 semi-structured interviews and one focus group with individuals involved in WTMS at the federal, provincial or organizational level. The most frequently cited local factor was physicians' participation. Physicians' leadership made the greatest difference in bringing resistant physicians on board. To be effective, however, local leadership had to be supported by senior management. Alignment of financial incentives between the contextual and local levels was also frequently cited, and interviewees stressed the importance of tools used to design, monitor, evaluate and prioritize WTMS. Finding the right balance between supportive resources and tools and an effective management system is a tough challenge. But achieving this balance will help reconcile contradictions between top-down and bottom-up WTMS.

  18. Lung cancer care trajectory at a Canadian centre: an evaluation of how wait times affect clinical outcomes.

    Science.gov (United States)

    Kasymjanova, G; Small, D; Cohen, V; Jagoe, R T; Batist, G; Sateren, W; Ernst, P; Pepe, C; Sakr, L; Agulnik, J

    2017-10-01

    Lung cancer continues to be one of the most common cancers in Canada, with approximately 28,400 new cases diagnosed each year. Although timely care can contribute substantially to quality of life for patients, it remains unclear whether it also improves patient outcomes. In this work, we used a set of quality indicators that aim to describe the quality of care in lung cancer patients. We assessed adherence with existing guidelines for timeliness of lung cancer care and concordance with existing standards of treatment, and we examined the association between timeliness of care and lung cancer survival. Patients with lung cancer diagnosed between 2010 and 2015 were identified from the Pulmonary Division Lung Cancer Registry at our centre. We demonstrated that the interdisciplinary pulmonary oncology service successfully treated most of its patients within the recommended wait times. However, there is still work to be done to decrease variation in wait time. Our results demonstrate a significant association between wait time and survival, supporting the need for clinicians to optimize the patient care trajectory. It would be helpful for Canadian clinicians treating patients with lung cancer to have wait time guidelines for all treatment modalities, together with standard definitions for all time intervals. Any reductions in wait times should be balanced against the need for thorough investigation before initiating treatment. We believe that our unique model of care leads to an acceleration of diagnostic steps. Avoiding any delay associated with referral to a medical oncologist for treatment could be an acceptable strategy with respect to reducing wait time.

  19. Arrival time pattern and waiting time distribution of patients in the emergency outpatient department of a tertiary level health care institution of North India

    Directory of Open Access Journals (Sweden)

    Yogesh Tiwari

    2014-01-01

    Full Text Available Background: Emergency Department (ED of tertiary health care institute in India is mostly overcrowded, over utilized and inappropriately staffed. The challenges of overcrowded EDs and ill-managed patient flow and admission processes result in excessively long waits for patients. Aim: The objective of the present study was to analyze the patient flow system by assessing the arrival and waiting time distribution of patients in an Emergency out Patient Department (EOPD. Materials and Methods: This short cross-sectional descriptive study was conducted in the EOPD of a Tertiary level health care Institution in North India in the month of May, 2011. The data was obtained from 591 patients, who were present in the EOPD during the month of May, 2011. The waiting time, inter arrival time between two consecutive patients were calculated in addition to the daily census data (discharge rate, admission rate and transfer out rates etc. of the emergency. Results: Arrival time pattern of patients in the EOPD was highly stochastic with the peak arrival hours to be "9.00-12.00 h" in which around 26.3% patients arrived in the EOPD. The primary waiting areas of patients included patients "under observation" (29.6%; "waiting for routine diagnostic tests" (16.4% and "waiting for discharge" (14.6%. Around 71% patients were waiting due to reasons within emergency complex. Conclusion: The patient flow of the ED could only be addressed by multifaceted, multidisciplinary and hospital wide approach.

  20. Cardiac EASE (Ensuring Access and Speedy Evaluation) – the impact of a single-point-of-entry multidisciplinary outpatient cardiology consultation program on wait times in Canada

    Science.gov (United States)

    Bungard, Tammy J; Smigorowsky, Marcie J; Lalonde, Lucille D; Hogan, Terry; Doliszny, Katharine M; Gebreyesus, Ghirmay; Garg, Sipi; Archer, Stephen L

    2009-01-01

    BACKGROUND: Universal access to health care is valued in Canada but increasing wait times for services (eg, cardiology consultation) raise safety questions. Observations suggest that deficiencies in the process of care contribute to wait times. Consequently, an outpatient clinic was designed for Ensuring Access and Speedy Evaluation (Cardiac EASE) in a university group practice, providing cardiac consultative services for northern Alberta. Cardiac EASE has two components: a single-point-of-entry intake service (prospective testing using physician-approved algorithms and previsit triage) and a multidisciplinary clinic (staffed by cardiologists, nurse practitioners and doctoral-trained pharmacists). OBJECTIVES: It was hypothesized that Cardiac EASE would reduce the time to initial consultation and a definitive diagnosis, and also increase the referral capacity. METHODS: The primary and secondary outcomes were time from referral to initial consultation, and time to achieve a definitive diagnosis and management plan, respectively. A conventionally managed historical control group (three-month pre-EASE period in 2003) was compared with the EASE group (2004 to 2006). The conventional referral mechanism continued concurrently with EASE. RESULTS: A comparison between pre-EASE (n=311) and EASE (n=3096) revealed no difference in the mean (± SD) age (60±16 years), sex (55% and 52% men, respectively) or reason for referral, including chest pain (31% and 40%, respectively) and arrhythmia (27% and 29%, respectively). Cardiac EASE reduced the time to initial cardiac consultation (from 71±45 days to 33±19 days) and time to a definitive diagnosis (from 120±86 days to 51±58 days) (P<0.0001). The annual number of new referrals increased from 1512 in 2002 to 2574 in 2006 due to growth in the Cardiac EASE clinic. The number of patients seen through the conventional referral mechanism and their wait times remained constant during the study period. CONCLUSIONS: Cardiac EASE reduced

  1. Seasonality of service provision in hip and knee surgery: a possible contributor to waiting times? A time series analysis.

    Science.gov (United States)

    Upshur, Ross E G; Moineddin, Rahim; Crighton, Eric J; Mamdani, Muhammad

    2006-03-01

    The question of how best to reduce waiting times for health care, particularly surgical procedures such as hip and knee replacements is among the most pressing concern of the Canadian health care system. The objective of this study was to test the hypothesis that significant seasonal variation exists in the performance of hip and knee replacement surgery in the province of Ontario. We performed a retrospective, cross-sectional time series analysis examining all hip and knee replacement surgeries in people over the age of 65 in the province of Ontario, Canada between 1992 and 2002. The main outcome measure was monthly hospitalization rates per 100,000 population for all hip and knee replacements. There was a marked increase in the rate of hip and knee replacement surgery over the 10-year period as well as an increasing seasonal variation in surgeries. Highly significant (Fisher Kappa = 16.05, p Holidays and utilization caps appear to exert a significant influence on the rate of service provision. It is expected that waiting times for hip and knee replacement could be reduced by reducing seasonal fluctuations in service provision and benchmarking services to peak delivery. The results highlight the importance of system behaviour in seasonal fluctuation of service delivery.

  2. Seasonality of service provision in hip and knee surgery: A possible contributor to waiting times? A time series analysis

    Directory of Open Access Journals (Sweden)

    Upshur Ross EG

    2006-03-01

    Full Text Available Abstract Background The question of how best to reduce waiting times for health care, particularly surgical procedures such as hip and knee replacements is among the most pressing concern of the Canadian health care system. The objective of this study was to test the hypothesis that significant seasonal variation exists in the performance of hip and knee replacement surgery in the province of Ontario. Methods We performed a retrospective, cross-sectional time series analysis examining all hip and knee replacement surgeries in people over the age of 65 in the province of Ontario, Canada between 1992 and 2002. The main outcome measure was monthly hospitalization rates per 100 000 population for all hip and knee replacements. Results There was a marked increase in the rate of hip and knee replacement surgery over the 10-year period as well as an increasing seasonal variation in surgeries. Highly significant (Fisher Kappa = 16.05, p 2Autoreg = 0.85 seasonality was identified in the data. Conclusion Holidays and utilization caps appear to exert a significant influence on the rate of service provision. It is expected that waiting times for hip and knee replacement could be reduced by reducing seasonal fluctuations in service provision and benchmarking services to peak delivery. The results highlight the importance of system behaviour in seasonal fluctuation of service delivery.

  3. 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.

  4. Waiting time analysis for MX/G/1 priority queues with/without vacations under random order of service discipline

    Directory of Open Access Journals (Sweden)

    Norikazu Kawasaki

    2000-01-01

    Full Text Available We study MX/G/1 nonpreemptive and preemptive-resume priority queues with/without vacations under random order of service (ROS discipline within each class. By considering the conditional waiting times given the states of the system, which an arbitrary message observes upon arrival, we derive the Laplace-Stieltjes transforms of the waiting time distributions and explicitly obtain the first two moments. The relationship for the second moments under ROS and first-come first-served disciplines extends the one found previously by Takacs and Fuhrmann for non-priority single arrival queues.

  5. Hospital competition, GP fundholders and waiting times in the UK internal market: the case of elective surgery.

    Science.gov (United States)

    Xavier, Ana

    2003-03-01

    In this paper I model the demand for and supply of elective surgery using a modified Hotelling framework in which time, money, and distance are determinants of the demand for hospital care. Hospitals compete with each other in terms of the waiting time and consequently treat a certain number of patients. The basic model of hospital competition is then extended to incorporate the general practitioner (GP) fundholding scheme whereby the GPs are allocated a budget with which to buy care for their patients. Waiting time increases when production of care becomes more expensive, when the benefit obtained from treatment increases, when the unit cost of distance decreases, and when the importance given to time as a performance indicator decreases. The higher the money price the lower the waiting time. Finally, the money price paid by the GP fundholders is greater than that paid by the Health Authorities and greater than the hospitals marginal cost of production. As a consequence, fundholding patients pay a zero time price while non-fundholding patients experiment a positive waiting time.

  6. Spin-resolved electron waiting times in a quantum-dot spin valve

    Science.gov (United States)

    Tang, Gaomin; Xu, Fuming; Mi, Shuo; Wang, Jian

    2018-04-01

    We study the electronic waiting-time distributions (WTDs) in a noninteracting quantum-dot spin valve by varying spin polarization and the noncollinear angle between the magnetizations of the leads using the scattering matrix approach. Since the quantum-dot spin valve involves two channels (spin up and down) in both the incoming and outgoing channels, we study three different kinds of WTDs, which are two-channel WTD, spin-resolved single-channel WTD, and cross-channel WTD. We analyze the behaviors of WTDs in short times, correlated with the current behaviors for different spin polarizations and noncollinear angles. Cross-channel WTD reflects the correlation between two spin channels and can be used to characterize the spin-transfer torque process. We study the influence of the earlier detection on the subsequent detection from the perspective of cross-channel WTD, and define the influence degree quantity as the cumulative absolute difference between cross-channel WTDs and first-passage time distributions to quantitatively characterize the spin-flip process. We observe that influence degree versus spin-transfer torque for different noncollinear angles as well as different polarizations collapse into a single curve showing universal behaviors. This demonstrates that cross-channel WTDs can be a pathway to characterize spin correlation in spintronics system.

  7. Poisson-process generalization for the trading waiting-time distribution in a double-auction mechanism

    Science.gov (United States)

    Cincotti, Silvano; Ponta, Linda; Raberto, Marco; Scalas, Enrico

    2005-05-01

    In this paper, empirical analyses and computational experiments are presented on high-frequency data for a double-auction (book) market. Main objective of the paper is to generalize the order waiting time process in order to properly model such empirical evidences. The empirical study is performed on the best bid and best ask data of 7 U.S. financial markets, for 30-stock time series. In particular, statistical properties of trading waiting times have been analyzed and quality of fits is evaluated by suitable statistical tests, i.e., comparing empirical distributions with theoretical models. Starting from the statistical studies on real data, attention has been focused on the reproducibility of such results in an artificial market. The computational experiments have been performed within the Genoa Artificial Stock Market. In the market model, heterogeneous agents trade one risky asset in exchange for cash. Agents have zero intelligence and issue random limit or market orders depending on their budget constraints. The price is cleared by means of a limit order book. The order generation is modelled with a renewal process. Based on empirical trading estimation, the distribution of waiting times between two consecutive orders is modelled by a mixture of exponential processes. Results show that the empirical waiting-time distribution can be considered as a generalization of a Poisson process. Moreover, the renewal process can approximate real data and implementation on the artificial stocks market can reproduce the trading activity in a realistic way.

  8. Statistical distributions of avalanche size and waiting times in an inter-sandpile cascade model

    Science.gov (United States)

    Batac, Rene; Longjas, Anthony; Monterola, Christopher

    2012-02-01

    Sandpile-based models have successfully shed light on key features of nonlinear relaxational processes in nature, particularly the occurrence of fat-tailed magnitude distributions and exponential return times, from simple local stress redistributions. In this work, we extend the existing sandpile paradigm into an inter-sandpile cascade, wherein the avalanches emanating from a uniformly-driven sandpile (first layer) is used to trigger the next (second layer), and so on, in a successive fashion. Statistical characterizations reveal that avalanche size distributions evolve from a power-law p(S)≈S-1.3 for the first layer to gamma distributions p(S)≈Sαexp(-S/S0) for layers far away from the uniformly driven sandpile. The resulting avalanche size statistics is found to be associated with the corresponding waiting time distribution, as explained in an accompanying analytic formulation. Interestingly, both the numerical and analytic models show good agreement with actual inventories of non-uniformly driven events in nature.

  9. A simple derivation of the waiting time distributions in a non-preemptive M/M/c queue with priorities

    NARCIS (Netherlands)

    van Vianen, Lars A.; Gabor, Adriana F.; van Ommeren, Jan C.W.

    2014-01-01

    In this article we give a new derivation for the waiting time distributions in an M=M=c queue with multiple priorities and a common service rate by using elementary lattice paths counting. An advantage of the approach is that it does not require inversion of the Laplace-Stieltjes transform.

  10. A simple derivation of the waiting time distributions in a non-preemptive M/M/c queue with priorities

    NARCIS (Netherlands)

    L.A. van Vianen (Lars); A.F. Gabor (Adriana); J.C.W. van Ommeren (Jan-Kees)

    2014-01-01

    textabstractIn this article we give a new derivation for the waiting time distributions in an M/M/c queue with multiple priorities and a common service rate by using elementary lattice paths counting. An advantage of the approach is that it does not require inversion of the Laplace-Stieltjes

  11. Improving Customer Waiting Time at a DMV Center Using Discrete-Event Simulation

    Science.gov (United States)

    Arnaout, Georges M.; Bowling, Shannon

    2010-01-01

    Virginia's Department of Motor Vehicles (DMV) serves a customer base of approximately 5.6 million licensed drivers and ID card holders and 7 million registered vehicle owners. DMV has more daily face-to-face contact with Virginia's citizens than any other state agency [1]. The DMV faces a major difficulty in keeping up with the excessively large customers' arrival rate. The consequences are queues building up, stretching out to the entrance doors (and sometimes even outside) and customers complaining. While the DMV state employees are trying to serve at their fastest pace, the remarkably large queues indicate that there is a serious problem that the DMV faces in its services, which must be dealt with rapidly. Simulation is considered as one of the best tools for evaluating and improving complex systems. In this paper, we use it to model one of the DMV centers located in Norfolk, VA. The simulation model is modeled in Arena 10.0 from Rockwell systems. The data used is collected from experts of the DMV Virginia headquarter located in Richmond. The model created was verified and validated. The intent of this study is to identify key problems causing the delays at the DMV centers and suggest possible solutions to minimize the customers' waiting time. In addition, two tentative hypotheses aiming to improve the model's design are tested and validated.

  12. Portuguese Society of Cardiothoracic and Vascular Surgery/Portuguese Society of Cardiology recommendations for waiting times for cardiac surgery.

    Science.gov (United States)

    Neves, José; Pereira, Hélder; Sousa Uva, Miguel; Gavina, Cristina; Leite Moreira, Adelino; Loureiro, Maria José

    2015-11-01

    Appointed jointly by the Portuguese Society of Cardiothoracic and Vascular Surgery (SPCCTV) and the Portuguese Society of Cardiology (SPC), the Working Group on Waiting Times for Cardiac Surgery was established with the aim of developing practical recommendations for clinically acceptable waiting times for the three critical phases of the care of adults with heart disease who require surgery or other cardiological intervention: cardiology appointments; the diagnostic process; and invasive treatment. Cardiac surgery has specific characteristics that are not comparable to other surgical specialties. It is important to reduce maximum waiting times and to increase the efficacy of systems for patient monitoring and tracking. The information in this document is mainly based on available clinical information. The methodology used to establish the criteria was based on studies on the natural history of heart disease, clinical studies comparing medical treatment with intervention, retrospective and prospective analyses of patients on waiting lists, and the opinions of experts and working groups. Following the first step, represented by publication of this document, the SPCCTV and SPC, as the bodies best suited to oversee this process, are committed to working together to define operational strategies that will reconcile the clinical evidence with the actual situation and with available resources. Copyright © 2015 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

  13. Algorithm for Compressing Time-Series Data

    Science.gov (United States)

    Hawkins, S. Edward, III; Darlington, Edward Hugo

    2012-01-01

    An algorithm based on Chebyshev polynomials effects lossy compression of time-series data or other one-dimensional data streams (e.g., spectral data) that are arranged in blocks for sequential transmission. The algorithm was developed for use in transmitting data from spacecraft scientific instruments to Earth stations. In spite of its lossy nature, the algorithm preserves the information needed for scientific analysis. The algorithm is computationally simple, yet compresses data streams by factors much greater than two. The algorithm is not restricted to spacecraft or scientific uses: it is applicable to time-series data in general. The algorithm can also be applied to general multidimensional data that have been converted to time-series data, a typical example being image data acquired by raster scanning. However, unlike most prior image-data-compression algorithms, this algorithm neither depends on nor exploits the two-dimensional spatial correlations that are generally present in images. In order to understand the essence of this compression algorithm, it is necessary to understand that the net effect of this algorithm and the associated decompression algorithm is to approximate the original stream of data as a sequence of finite series of Chebyshev polynomials. For the purpose of this algorithm, a block of data or interval of time for which a Chebyshev polynomial series is fitted to the original data is denoted a fitting interval. Chebyshev approximation has two properties that make it particularly effective for compressing serial data streams with minimal loss of scientific information: The errors associated with a Chebyshev approximation are nearly uniformly distributed over the fitting interval (this is known in the art as the "equal error property"); and the maximum deviations of the fitted Chebyshev polynomial from the original data have the smallest possible values (this is known in the art as the "min-max property").

  14. Distributed Algorithms for Time Optimal Reachability Analysis

    DEFF Research Database (Denmark)

    Zhang, Zhengkui; Nielsen, Brian; Larsen, Kim Guldstrand

    2016-01-01

    . We propose distributed computing to accelerate time optimal reachability analysis. We develop five distributed state exploration algorithms, implement them in \\uppaal enabling it to exploit the compute resources of a dedicated model-checking cluster. We experimentally evaluate the implemented...... algorithms with four models in terms of their ability to compute near- or proven-optimal solutions, their scalability, time and memory consumption and communication overhead. Our results show that distributed algorithms work much faster than sequential algorithms and have good speedup in general.......Time optimal reachability analysis is a novel model based technique for solving scheduling and planning problems. After modeling them as reachability problems using timed automata, a real-time model checker can compute the fastest trace to the goal states which constitutes a time optimal schedule...

  15. A prospective study on the impact of waiting times for radiotherapy ...

    African Journals Online (AJOL)

    Background: Radiotherapy plays a vital role in the management of cervical cancer. However, because of high patient load and limited resources, waiting lists are unacceptably long. This is a highly curable malignancy that often occurs in economically active, relatively young women. The impact of treatment delays on society ...

  16. Improved functional outcome after hip fracture is associated with duration of rehabilitation, but not with waiting time for rehabilitation

    DEFF Research Database (Denmark)

    Pedersen, Tonny Jaeger; Bogh, Louise Nicole Bie; Lauritsen, Jens Martin

    2017-01-01

    INTRODUCTION: The aim of this study was to explore the relationship between “waiting time to onset of municipal rehabilitation”, “length of municipal rehabilitation” and the attained level of function four months after the hip fracture. METHODS: Among a consecutive series of 156 patients, the 116...... duration of municipal rehabilitation and outcome, also at four months. No marked differences in these results were found when subgrouped by pre-fracture level of function as assessed with the Barthel-20 index. CONCLUSIONS: Waiting times from hospital discharge to initiation of municipal rehabilitation...... seems not to correlate with functional level four months after the hip fracture. In contrast, the amount of municipal rehabilitation time does correlate with a better functional level four months after the hip fracture. Furthermore, large-sample studies are warranted to clarify this relationship....

  17. Change of tumor target volume during waiting time for intensity-modulated radiotherapy (IMRT) in nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Chen Bo; Yi Junlin; Gao Li; Xu Guozhen; Huang Xiaodong; Zhang Zhong; Luo Jingwei; Li Suyan

    2007-01-01

    Objective: To determine the influence of change in tumor target volume of nasopharyngeal carcinoma (NPC) while waiting for intensity modulated radiation therapy (IMRT). Methods: From March 2005 to December 2005, 31 patients with nasopharyngeal carcinoma received IMRT as the initial treatment at the Cancer Hospital of Chinese Academic of Medical Sciences. The original simulation CT scan was acquired before IMRT planning. A second CT scan was acquired before the start of radiotherapy. Wait- ing time was defined as the duration between CT simulation and start of radiotherapy. CT-CT fusion was used to minimize the error of delineation between the first tumor target volume (GTV) and the second tumor target volume (sGTV). Tumor target volume was calculated by treatment planning system. T test was carried out to analyse the difference between GTV and sGTV. Pearson correlation and multivariate linear regression was used to analyse the influence factor of the change betweent GTV and sGTV. Results: Median waiting time was 18 days (range, 9-27 days). There were significant differences between GTV and sGTV of both primary tumor (P=0.009) and metastatic lymphoma (P=0.005 ). Both Pearson correlation and multivariate linear regression showed that the change of primary tumor target volume had significant correlation with the first tumor target volume but had no significant correlation with the waiting time, sex, age, T stage and N stage (1992 Chinese Fuzhou Staging Classification). Conclusions: Within the range of the waiting time ob- served in our study, large volume primary tumor would have had a significant increase in volume, but whether the therapeutic effect would be influenced or not would need to be proved by study of large number of cases. Patients with large volume tumor should be considered to reduce the influence of waiting time by enlarging gross target volume and clinical targe volume and by neoadjuveant chemotherapy. For avoiding the unnecessary high-dose to normal

  18. Waiting Time for Coronal Preparation and the Influence of Different Cements on Tensile Strength of Metal Posts

    Directory of Open Access Journals (Sweden)

    Ilione Kruschewsky Costa Sousa Oliveira

    2012-01-01

    Full Text Available This study aimed to assess the effect of post-cementation waiting time for core preparation of cemented cast posts and cores had on retention in the root canal, using two different luting materials. Sixty extracted human canines were sectioned 16 mm from the root apex. After cast nickel-chromium metal posts and cores were fabricated and luted with zinc phosphate (ZP cement or resin cement (RC, the specimens were divided into 3 groups (n = 10 according to the waiting time for core preparation: no preparation (control, 15 minutes, or 1 week after the core cementation. At the appropriate time, the specimens were subjected to a tensile load test (0.5 mm/min until failure. Two-way ANOVA (time versus cement and the Tukey tests (P < 0.05 showed significantly higher (P < 0.05 tensile strength values for the ZP cement groups than for the RC groups. Core preparation and post-cementation waiting time for core recontouring did not influence the retention strength. ZP was the best material for intraradicular metal post cementation.

  19. Prototype of a Questionnaire and Quiz System for Supporting Increase of Health Awareness During Wait Time in Dispensing Pharmacy

    Science.gov (United States)

    Toda, Takeshi; Chen, Poa-Min; Ozaki, Shinya; Ideguchi, Naoko; Miyaki, Tomoko; Nanbu, Keiko; Ikeda, Keiko

    For quit-smoking clinic and its campaign, there was a need for pharmacists to investigate pediatric patient's parent consciousness to tobacco harm utilizing wait time in a pediatric dispensing pharmacy. In this research, we developed the questionnaire and quiz total system using the tablet for user interface, in which people can easily answer the questionnaire/quiz and quickly see the total results on the spot in order to enhance their consciousness to the tobacco harm. The system also provides their tobacco dependence level based on the questionnaire results and some advice for their health and dietary habits due to the tobacco dependence level. From a field trial with one hundred four examinees in the pediatric dispensing pharmacy, the user interface was useful compared to conventional questionnaire form. The system could enhance their consciousness to tobacco harm and make their beneficial use of waiting time in dispensing pharmacy. Some interesting suggestions for improvement and new services were also obtained.

  20. Quality management: reduction of waiting time and efficiency enhancement in an ENT-university outpatients' department

    Science.gov (United States)

    Helbig, Matthias; Helbig, Silke; Kahla-Witzsch, Heike A; May, Angelika

    2009-01-01

    Background Public health systems are confronted with constantly rising costs. Furthermore, diagnostic as well as treatment services become more and more specialized. These are the reasons for an interdisciplinary project on the one hand aiming at simplification of planning and scheduling patient appointments, on the other hand at fulfilling all requirements of efficiency and treatment quality. Methods As to understanding procedure and problem solving activities, the responsible project group strictly proceeded with four methodical steps: actual state analysis, analysis of causes, correcting measures, and examination of effectiveness. Various methods of quality management, as for instance opinion polls, data collections, and several procedures of problem identification as well as of solution proposals were applied. All activities were realized according to the requirements of the clinic's ISO 9001:2000 certified quality management system. The development of this project is described step by step from planning phase to inauguration into the daily routine of the clinic and subsequent control of effectiveness. Results Five significant problem fields could be identified. After an analysis of causes the major remedial measures were: installation of a patient telephone hotline, standardization of appointment arrangements for all patients, modification of the appointments book considering the reason for coming in planning defined working periods for certain symptoms and treatments, improvement of telephonic counselling, and transition to flexible time planning by daily updates of the appointments book. After implementation of these changes into the clinic's routine success could be demonstrated by significantly reduced waiting times and resulting increased patient satisfaction. Conclusion Systematic scrutiny of the existing organizational structures of the outpatients' department of our clinic by means of actual state analysis and analysis of causes revealed the necessity

  1. Does Weight Gain During the Operation Wait Time Have an Impact on Weight Loss After Laparoscopic Sleeve Gastrectomy?

    Science.gov (United States)

    Cayci, Haci Murat; Erdogdu, Umut Eren; Karaman, Kerem; Budak, Ersin; Taymur, İbrahim; Buyukuysal, Cagatay

    2017-02-01

    The effect of preoperative weight changes on postoperative outcomes after bariatric surgery remains inconclusive. The aim of the present study was to evaluate the effect of preoperative weight gain on postoperative weight loss outcomes after laparoscopic sleeve gastrectomy (SG). Ninety-two morbidly obese patients undergoing SG from January 2014 to April 2016 were separated into two groups according to whether they gained weight or not during the waiting time prior to surgery. Thirty-nine patients (42.4 %) gained weight during the waiting time and 53 patients (57.6 %) did not. The median body mass index (BMI; kg/m 2 ) at surgery was significantly higher in weight-gained patients (47.8 (min-max, 40-62)) compared to patients who had not gained weight (45.10 (min-max, 41-67)), (P = 0.034). No significant difference was found between the two groups regarding the distribution of age, gender, family history of obesity, existence of comorbidity, smoking, weight gain during childhood or adulthood, preoperative Beck depression and Beck anxiety scores, waiting time period, and body weight at the initial visit (P > 0.05). The ASA I score was higher in weight-gained patients whereas ASA II score was higher in those who did not gain, and the difference was significant (P = 0.046). Postoperative % BMI loss and % weight loss were not significantly different between the two groups at the first, third, sixth months, and the end of the first year (P > 0.05). Weight gain during waiting time has no negative impact on % weight loss and % BMI loss after SG.

  2. 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.

  3. The relationship between waiting time for radiotherapy and clinical outcomes: A systematic review of the literature

    International Nuclear Information System (INIS)

    Chen Zheng; King, Will; Pearcey, Robert; Kerba, Marc; Mackillop, William J.

    2008-01-01

    Purpose: To synthesize the direct clinical evidence relating waiting times (WTs) for radiotherapy (RT) to the outcomes of RT. Methods and materials: We did a systematic review of the literature between 1975 and 2005 to identify clinical studies describing the relationship between WTs and outcomes of RT. Only high quality (HQ) studies that had adequately controlled for confounding factors were included in the primary analysis. WTs that had originally been reported as a categorical variable were converted to a continuous variable based on the distribution of WTs in each category. Meta-analyses were done using a fixed-effect model. Results: The systematic review identified 44 relevant studies. Meta-analyses of 20 HQ studies of local control demonstrated a significant increase in the risk of local failure with increasing WT, RR localrecurrence/month = 1.14, 95% Confidence Intervals (CI): 1.09-1.21. For post-operative RT for breast cancer; RR localrecurrence/month = 1.11, 95%CI: 1.04-1.19. For post-operative RT for head and neck cancer, RR localrecurrenc/month = 1.28, 95%CI: 1.08-1.52. For definitive RT for head and neck cancer, RR localrecurrence/month = 1.15, 95%CI: 1.02-1.29. There was little evidence of any association between WTs and the risk of distant metastasis. Meta-analyses of the 6 HQ studies of breast cancer showed RR metastasis/month = 1.04, 95%CI: 0.98-1.09. Meta-analyses of 4 HQ studies of breast cancer showed no significant decrease in survival with increasing WT, RR death/month = 1.06, 95%CI: 0.97-1.16, but there was a marginally significant decrease in survival in 4 HQ studies of head and neck cancer, RR death/month = 1.16, 95%CI: 1.02-1.32. Conclusions: The risk of local recurrence increases with increasing WTs for RT. The increase in local recurrence rate may translate into decreased survival in some clinical situations. WTs for RT should be as short as reasonably achievable

  4. Impact of 'Ideal Clinic' implementation on patient waiting time in primary healthcare clinics in KwaZulu-Natal Province, South Africa: A before-and-after evaluation.

    Science.gov (United States)

    Egbujie, B A; Grimwood, A; Mothibi-Wabafor, E C; Fatti, G; Tshabalala, A M E T; Allie, S; Vilakazi, G; Oyebanji, O

    2018-03-28

    Long waiting times are a major source of dissatisfaction for patients attending public healthcare facilities in South Africa (SA). The National Department of Health has identified this as one of six priority areas for improvement. Health system-strengthening (HSS) interventions to improve patient waiting time are being implemented in public health facilities across SA as part of the 'Ideal Clinic' model. The effect of these interventions on patient waiting time needs to be assessed and evidence generated for system improvement. To determine the effect of Ideal Clinic HSS intervention on patient waiting time in public health facilities in Amajuba District, KwaZulu-Natal Province, SA. We implemented 12 months of HSS activity, including facility reorganisation and patient appointment scheduling. The major outcome of interest was the total time spent by patients in a facility during a visit. This was calculated as the median time spent, obtained through a 'before-and-after' intervention survey. Univariate and multivariate factors associated with waiting time were determined. A total of 1 763 patients from nine clinics were surveyed before and after the intervention (n=860 at baseline and n=903 at follow-up). The median overall waiting time after the intervention was 122 minutes (interquartile range (IQR) 81 - 204), compared with 116 minutes (IQR 66 - 168) before (p<0.05). Individual facility results after the intervention were mixed. Two facilities recorded statistically significant reductions in patient waiting time, while three recorded significant increases (p<0.05). Patient load per nurse, type of service received and time of arrival in facilities were all independently associated with waiting time. Patients' arrival patterns, which were determined by appointment scheduling, played a significant role in the results obtained. Implementation of the Ideal Clinic model in the selected facilities led to changes in patient waiting time. Observed changes were

  5. The influence of waiting time satisfaction on customer loyalty towards multi-stage services in a full-service restaurant: evidence from India

    OpenAIRE

    MITTAL A.

    2016-01-01

    Research shows waiting time in services is an important source of service evaluation by the customer. In fact, time is one component of the total 'cost' that the customer bears and cost is a core component of the perceived cost-benefit equation that the customer uses to evaluate her or his sustained patronage of a particular service. In most services, customers consider waiting as a waste of time. However, from the customer perspective, in the case of a full-service restaurant, waiting is exp...

  6. Use of queue modelling in the analysis of elective patient treatment governed by a maximum waiting time policy

    DEFF Research Database (Denmark)

    Kozlowski, Dawid; Worthington, Dave

    2015-01-01

    chain and discrete event simulation models, to provide an insightful analysis of the public hospital performance under the policy rules. The aim of this paper is to support the enhancement of the quality of elective patient care, to be brought about by better understanding of the policy implications...... on the utilization of public hospital resources. This paper illustrates the use of a queue modelling approach in the analysis of elective patient treatment governed by the maximum waiting time policy. Drawing upon the combined strengths of analytic and simulation approaches we develop both continuous-time Markov...

  7. No More Waits and Delays: Streamlining Workflow to Decrease Patient Time of Stay for Image-guided Musculoskeletal Procedures.

    Science.gov (United States)

    Cheung, Yvonne Y; Goodman, Eric M; Osunkoya, Tomiwa O

    2016-01-01

    Long wait times limit our ability to provide the right care at the right time and are commonly products of inefficient workflow. In 2013, the demand for musculoskeletal (MSK) procedures increased beyond our department's ability to provide efficient and timely service. We initiated a quality improvement (QI) project to increase efficiency and decrease patient time of stay. Our project team included three MSK radiologists, one senior resident, one technologist, one administrative assistant/scheduler, and the lead technologist. We adopted and followed the Lean Six Sigma DMAIC (define, measure, analyze, improve, and control) approach. The team used tools such as voice of the customer (VOC), along with affinity and SIPOC (supplier, input, process, output, customer) diagrams, to understand the current process, identify our customers, and develop a project charter in the define stage. During the measure stage, the team collected data, created a detailed process map, and identified wastes with the value stream mapping technique. Within the analyze phase, a fishbone diagram helped the team to identify critical root causes for long wait times. Scatter plots revealed relationships among time variables. Team brainstorming sessions generated improvement ideas, and selected ideas were piloted via plan, do, study, act (PDSA) cycles. The control phase continued to enable the team to monitor progress using box plots and scheduled reviews. Our project successfully decreased patient time of stay. The highly structured and logical Lean Six Sigma approach was easy to follow and provided a clear course of action with positive results. (©)RSNA, 2016.

  8. Development of a minimization instrument for allocation of a hospital-level performance improvement intervention to reduce waiting times in Ontario emergency departments

    Directory of Open Access Journals (Sweden)

    Anderson Geoff

    2009-06-01

    Full Text Available Abstract Background Rigorous evaluation of an intervention requires that its allocation be unbiased with respect to confounders; this is especially difficult in complex, system-wide healthcare interventions. We developed a short survey instrument to identify factors for a minimization algorithm for the allocation of a hospital-level intervention to reduce emergency department (ED waiting times in Ontario, Canada. Methods Potential confounders influencing the intervention's success were identified by literature review, and grouped by healthcare setting specific change stages. An international multi-disciplinary (clinical, administrative, decision maker, management panel evaluated these factors in a two-stage modified-delphi and nominal group process based on four domains: change readiness, evidence base, face validity, and clarity of definition. Results An original set of 33 factors were identified from the literature. The panel reduced the list to 12 in the first round survey. In the second survey, experts scored each factor according to the four domains; summary scores and consensus discussion resulted in the final selection and measurement of four hospital-level factors to be used in the minimization algorithm: improved patient flow as a hospital's leadership priority; physicians' receptiveness to organizational change; efficiency of bed management; and physician incentives supporting the change goal. Conclusion We developed a simple tool designed to gather data from senior hospital administrators on factors likely to affect the success of a hospital patient flow improvement intervention. A minimization algorithm will ensure balanced allocation of the intervention with respect to these factors in study hospitals.

  9. Development of a minimization instrument for allocation of a hospital-level performance improvement intervention to reduce waiting times in Ontario emergency departments.

    Science.gov (United States)

    Leaver, Chad Andrew; Guttmann, Astrid; Zwarenstein, Merrick; Rowe, Brian H; Anderson, Geoff; Stukel, Therese; Golden, Brian; Bell, Robert; Morra, Dante; Abrams, Howard; Schull, Michael J

    2009-06-08

    Rigorous evaluation of an intervention requires that its allocation be unbiased with respect to confounders; this is especially difficult in complex, system-wide healthcare interventions. We developed a short survey instrument to identify factors for a minimization algorithm for the allocation of a hospital-level intervention to reduce emergency department (ED) waiting times in Ontario, Canada. Potential confounders influencing the intervention's success were identified by literature review, and grouped by healthcare setting specific change stages. An international multi-disciplinary (clinical, administrative, decision maker, management) panel evaluated these factors in a two-stage modified-delphi and nominal group process based on four domains: change readiness, evidence base, face validity, and clarity of definition. An original set of 33 factors were identified from the literature. The panel reduced the list to 12 in the first round survey. In the second survey, experts scored each factor according to the four domains; summary scores and consensus discussion resulted in the final selection and measurement of four hospital-level factors to be used in the minimization algorithm: improved patient flow as a hospital's leadership priority; physicians' receptiveness to organizational change; efficiency of bed management; and physician incentives supporting the change goal. We developed a simple tool designed to gather data from senior hospital administrators on factors likely to affect the success of a hospital patient flow improvement intervention. A minimization algorithm will ensure balanced allocation of the intervention with respect to these factors in study hospitals.

  10. The determinants of patient waiting time in the general outpatient department of Debre Markos and Felege Hiwot hospitals in Amhara regional state, North West, Ethiopia

    Directory of Open Access Journals (Sweden)

    Melesse Belayneh

    2017-01-01

    Full Text Available Background Patient waiting time is defined as the total time from registration until consultation with a doctor. Experiences of waiting in general are perceived as complex, subjective, and culturally influenced. Registration time, payment process/cash billing, recording classification/triaged time, few human resources and work process are the determinants of patient waiting time in the general outpatient departments. However, the complexity of wait time is poorly understood and has been explored only to a limited extent. The main objective of this study to assess patient waiting time and its determinants in Debre Markos and Felge Hiwot Referral hospitals of Amhara Regional State in North West, Ethiopia. Methods A hospital based comparative cross sectional study design was employed from October 20‐ November 20, 2014. The study population was patients presenting to general outpatient departments, from which 464 patients was selected using systematic random sampling technique. Quantitative Data was collected using structured questionnaire and A check list adopted from studies. Quantitative data was coded, entered, cleaned and analyzed using SPSS Software for windows version 20.0. Linear regression and bivariate logistic regression was applied to identify the determinants of each explanatory variable on outcome (patient waiting time. Finally data was interpreted by referring to the pertinent findings from the relevant literature reviewed. Ethical approval and clearance was obtained from ethical clearance committee of the Jimma University College of Public Health & Medical Sciences Result The measured waiting time in Felge Hiwot referral hospital mean waiting time was and its standard deviation 149.2±72.1 minutes whereas 94.2±58.3 minutes in debere markos referral hospital. The major causes of the long patient waiting time was large numbers of patient with a few doctors 94(40.5%,67(28.9% ,long searching of the cards 67(28.9%,73(31.5,and long

  11. Waiting when hospitalised

    DEFF Research Database (Denmark)

    Ludvigsen, Mette Spliid

    2004-01-01

    on participating observations during a period of one and a half year. The material is analysed with inspiration from Mattingly's ideas of narrative and time. ConclusionsAlthough waiting times is not a clinically serious problem, the satisfaction levels of patients with the care they receive have become...... increasingly important in today's health care environment. The indicative conclusions form this study suggest that nurses play an important role in ensuring that patients are satisfied and receive quality care when waiting....

  12. Waiting Time for Start of Outpatient Cardiac Rehabilitation: Correlations of Non Compliance to Systematic Referral After Coronary Artery Bypass Surgery

    Directory of Open Access Journals (Sweden)

    Ali Soroush

    2016-04-01

    Full Text Available Objectives To assess the waiting time, number of delays, and correlations of non-commitment to the systematic referral to the outpatient cardiac rehabilitation (CR among coronary artery bypass surgery (CABG patients. Methods The cross-sectional study data were gathered through evaluations related to 1,187 CABG patients who were referred to the outpatient CR of 1 hospital in western Iran during 2010 to 2014. The instruments included were demographics and actual risk factors checklist, single item of perceived risk factors, and Beck depression inventory (BDI. Data was analyzed via chi-square test, ANOVA, Bonferroni post hoc test, and binary logistic regression analysis. Results Among 1 187 patients (830 male, 27% had delayed referral, and the number of delays decreased from 2010 (49.3% to 2014 (7.6% (P < 0.001. The mean of the waiting time to receive outpatient CR in western Iran was an estimated 59 days. This mean has been reduced from 66 days (2010 to 53 days (2014 (P < 0.001. After adjustment for all demographics, the results indicated that diabetic patients (P = 0.002 and patients with biological (P = 0.002, behavioral (P = 0.003, or psychological (P = 0.002 perceived risk factors have less commitment. In addition, a family history of cardiac increases the possibility of commitment as 2.41 times (P < 0.001. Conclusions Despite the progressive process of patients’ admittance and acceptability of the present waiting time, especially after 2014, it seems that more attention to diabetic patients and patients without a family history of cardiac, and modification of attitudes about multiple risk factors can associate the self-care with more responsibility and it may also be affective in the control of harm consequences through commitment to the systematic referral.

  13. Reduction of client waiting time using task shifting in an antiretroviral clinic at Specialist Hospital Bauchi, Nigeria

    Directory of Open Access Journals (Sweden)

    Nisser A. Umar

    2011-02-01

    Full Text Available Aiming to assess the impact of the intervention in reducing the patients’ waiting time in the clinic, two surveys were conducted before and after task shifting intervention in an anti-retroviral (ARV clinic at the Specialist Hospital, Bauchi, Nigeria in November 2008 and April 2009, respectively. Before the task shifting, six nurses from the clinic were trained on integrated management of adolescent and adult illness, as well as on the principle and guidelines for the anti-retroviral therapy, after which their schedule in the clinic was broadened to include seeing HIV patients presenting for routine refill and follow-up visits. In this study, fifty-six and sixty patients, respectively out of 186 and 202 who attended the clinic on the days of the pre- and post-intervention surveys, were randomly sampled. Data on patients’ sex, age and marital status, whether patient a first timer or follow up visitor and the time spent in the clinic on that day as well as the number and composition of staff and equipment in the clinic was collected. The difference in waiting time spent between the first group before task shifting and second group after task shifting was statistically analyzed and significance tested using unpaired t- test. There was a reduction in the average waiting time for patients attending the clinic from 6.48 h before task shifting to 4.35 h after task shifting. The difference of mean was -2.13 h, with 95% CI: -2.44:-1.82 hours and the test of significance by unpaired t-test P

  14. Analysis of bluetooth and wi-fi technology to measure wait times of personal vehicles at Arizona-Mexico ports of entry : [executive summary].

    Science.gov (United States)

    2015-11-01

    The Arizona Department of Transportation (ADOT), Office of P3 Initiatives and International : Affairs selected Lee Engineering to analyze the penetration rate of Anonymous Re-Identification : (ARID) technology to measure wait time of U.S. and Mexico ...

  15. Applying the Lean principles of the Toyota Production System to reduce wait times in the emergency department.

    Science.gov (United States)

    Ng, David; Vail, Gord; Thomas, Sophia; Schmidt, Nicki

    2010-01-01

    In recognition of patient wait times, and deteriorating patient and staff satisfaction, we set out to improve these measures in our emergency department (ED) without adding any new funding or beds. In 2005 all staff in the ED at Hôtel-Dieu Grace Hospital began a transformation, employing Toyota Lean manufacturing principles to improve ED wait times and quality of care. Lean techniques such as value-stream mapping, just-in-time delivery techniques, workplace organization, reduction of systemic wastes, use of the worker as the source of quality improvement and ongoing refinement of our process steps formed the basis of our project. Our ED has achieved major improvements in departmental flow without adding any additional ED or inpatient beds. The mean registration to physician time has decreased from 111 minutes to 78 minutes. The number of patients who left without being seen has decreased from 7.1% to 4.3%. The length of stay (LOS) for discharged patients has decreased from a mean of 3.6 to 2.8 hours, with the largest decrease seen in our patients triaged at levels 4 or 5 using the Canadian Emergency Department Triage and Acuity Scale. We noted an improvement in ED patient satisfaction scores following the implementation of Lean principles. Lean manufacturing principles can improve the flow of patients through the ED, resulting in greater patient satisfaction along with reduced time spent by the patient in the ED.

  16. Sustainability of Routine Notification and Request legislation on eye bank tissue supply and corneal transplantation wait times in Canada.

    Science.gov (United States)

    Lee, Kenneth; Boimer, Corey; Hershenfeld, Samantha; Sharpen, Linda; Slomovic, Allan R

    2011-10-01

    To assess whether provinces with Routine Notification and Request (RNR) legislation have sustained increases in corneal tissue supply and decreases in wait times for corneal transplantation surgery. Cross-sectional survey of Canadian corneal transplant (CT) surgeons and eye banks. Canadian CT surgeons and representatives from the 10 Canadian eye banks. Voluntary and anonymous surveys were distributed between July and October 2009. Eligible CT surgeons were defined as ophthalmologists who practice in Canada; currently perform Penetrating keratoplasty (PKP), Deep anterior lamellar keratoplasty (DALK), Deep lamellar endothelial keratoplasty (DLEK), Descemet stripping endothelial keratoplasty (DSEK), or Descemet membrane endothelial keratoplasty (DMEK); and have obtained tissues from a Canadian eye bank. From 2006 to 2009, for provinces with RNR legislation and where data are available, mean wait times from date of diagnosis to date of CT surgery have increased: in Ontario, from 31 ± 34 weeks to 36 ± 27 weeks; in British Columbia, from 39 ± 20 weeks to 42 ± 35 weeks; in Manitoba, from 32 ± 23 weeks to 49 ± 36 weeks. In addition, the amount of corneal tissue in RNR provinces suitable for transplant, with the exception of British Columbia, has declined between 2006 and 2008: in Ontario, 1186 tissues to 999 tissues (16% decline); in Manitoba, 92 tissues to 83 tissues (10% decline); in New Brunswick, 129 tissues to 98 tissues (24% decline). Although initially effective, RNR legislation has not sustained an increase in corneal tissue availability nor has it shortened wait times in most provinces. Incorporation of community hospitals into the RNR catchment, improved enforcement, and continued education of hospital staff regarding the RNR process may be effective in making this legislation more sustainable in the long term. Copyright © 2011 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

  17. Wait times to rheumatology care for patients with rheumatic diseases: a data linkage study of primary care electronic medical records and administrative data.

    Science.gov (United States)

    Widdifield, Jessica; Bernatsky, Sasha; Thorne, J Carter; Bombardier, Claire; Jaakkimainen, R Liisa; Wing, Laura; Paterson, J Michael; Ivers, Noah; Butt, Debra; Lyddiatt, Anne; Hofstetter, Catherine; Ahluwalia, Vandana; Tu, Karen

    2016-01-01

    The Wait Time Alliance recently established wait time benchmarks for rheumatology consultations in Canada. Our aim was to quantify wait times to primary and rheumatology care for patients with rheumatic diseases. We identified patients from primary care practices in the Electronic Medical Record Administrative data Linked Database who had referrals to Ontario rheumatologists over the period 2000-2013. To assess the full care pathway, we identified dates of symptom onset, presentation in primary care and referral from electronic medical records. Dates of rheumatologist consultations were obtained by linking with physician service claims. We determined the duration of each phase of the care pathway (symptom onset to primary care encounter, primary care encounter to referral, and referral to rheumatologist consultation) and compared them with established benchmarks. Among 2430 referrals from 168 family physicians, 2015 patients (82.9%) were seen by 146 rheumatologists within 1 year of referral. Of the 2430 referrals, 2417 (99.5%) occurred between 2005 and 2013. The main reasons for referral were osteoarthritis (32.4%) and systemic inflammatory rheumatic diseases (30.6%). Wait times varied by diagnosis and geographic region. Overall, the median wait time from referral to rheumatologist consultation was 74 (interquartile range 27-101) days; it was 66 (interquartile range 18-84) days for systemic inflammatory rheumatic diseases. Wait time benchmarks were not achieved, even for the most urgent types of referral. For systemic inflammatory rheumatic diseases, most of the delays occurred before referral. Rheumatology wait times exceeded established benchmarks. Targeted efforts are needed to promote more timely access to both primary and rheumatology care. Routine linkage of electronic medical records with administrative data may help fill important gaps in knowledge about waits to primary and specialty care.

  18. Managing patients' wait time in specialist out-patient clinic using real-time data from existing queue management and ADT systems.

    Science.gov (United States)

    Ju, John Chen; Gan, Soon Ann; Tan Siew Wee, Justine; Huang Yuchi, Peter; Mei Mei, Chan; Wong Mei Mei, Sharon; Fong, Kam Weng

    2013-01-01

    In major cancer centers, heavy patients load and multiple registration stations could cause significant wait time, and can be result in patient complains. Real-time patient journey data and visual display are useful tools in hospital patient queue management. This paper demonstrates how we capture patient queue data without deploying any tracing devices; and how to convert data into useful patient journey information to understand where interventions are likely to be most effective. During our system development, remarkable effort has been spent on resolving data discrepancy and balancing between accuracy and system performances. A web-based dashboard to display real-time information and a framework for data analysis were also developed to facilitate our clinics' operation. Result shows our system could eliminate more than 95% of data capturing errors and has improved patient wait time data accuracy since it was deployed.

  19. Patient perceptions regarding physician reimbursements, wait times, and out-of-pocket payments for anterior cruciate ligament reconstruction in Ontario.

    Science.gov (United States)

    Memon, Muzammil; Ginsberg, Lydia; de Sa, Darren; Nashed, Andrew; Simunovic, Nicole; Phillips, Mark; Denkers, Matthew; Ogilvie, Rick; Peterson, Devin; Ayeni, Olufemi R

    2017-12-01

    Currently, there is a lack of knowledge regarding patient perceptions surrounding physician reimbursements, appropriate wait times, and out-of-pocket payment options for anterior cruciate ligament reconstruction (ACLR). Our objective was to determine the current state of these perceptions in an Ontario setting. A survey was developed and pretested to address patient perceptions about physician reimbursements, appropriate wait times, and out-of-pocket payment options for ACLR using a focus group of experts and by reviewing prior surveys. The survey was administered to patients in a waiting room setting. Two hundred and fifty completed surveys were obtained (79.9% response rate). Participants responded that an appropriate physician reimbursement for ACLR was $1000.00 and that the Ontario Health Insurance Plan (OHIP) reimbursed physicians $700.00 for ACLR. Seventy-four percent of participants responded that the OHIP reimbursement of $615.20 for the procedure was either lower or much lower than what they considered to be an appropriate reimbursement for ACLR. Over 90% of participants responded that an ACLR should occur within 90 days of injury. Thirty-five percent of participants were willing to pay $750.00 out-of-pocket to have an ACLR done sooner, while 16.4% of participants were willing to pay $2500.00 out-of-pocket to travel outside of Canada for expedited surgery. This survey study demonstrates that patients' estimates of both appropriate and actual physician reimbursements were greater than the current reimbursement for ACLR. Further, the majority of individuals report that the surgical fee for ACLR is lower than what they consider to be an appropriate amount of compensation for the procedure. Additionally, nearly all respondents believe that a ruptured ACL should be reconstructed within 90 days of injury. Consequently, a number of patients are willing to pay out-of-pocket for expedited surgery either in Canada or abroad. However, patients' preferences for

  20. Poster - 26: Electronic Waiting Room Management for a busy Cancer Centre

    Energy Technology Data Exchange (ETDEWEB)

    Kildea, John; Hijal, Tarek [McGill University Health Center (Canada)

    2016-08-15

    We describe an electronic waiting room management system that we have developed and deployed in our cancer centre. Our system connects with our electronic medical records systems, gathers data for a machine learning algorithm to predict future patient waiting times, and is integrated with a mobile phone app. The system has been in operation for over nine months and has led to reduced lines, calmer waiting rooms and overwhelming patient and staff satisfaction.

  1. Poster - 26: Electronic Waiting Room Management for a busy Cancer Centre

    International Nuclear Information System (INIS)

    Kildea, John; Hijal, Tarek

    2016-01-01

    We describe an electronic waiting room management system that we have developed and deployed in our cancer centre. Our system connects with our electronic medical records systems, gathers data for a machine learning algorithm to predict future patient waiting times, and is integrated with a mobile phone app. The system has been in operation for over nine months and has led to reduced lines, calmer waiting rooms and overwhelming patient and staff satisfaction.

  2. Using lean manufacturing principles to evaluate wait times for HIV-positive patients in an urban clinic in Kenya.

    Science.gov (United States)

    Monroe-Wise, Aliza; Reisner, Elizabeth; Sherr, Kenneth; Ojakaa, David; Mbau, Lilian; Kisia, Paul; Muhula, Samuel; Farquhar, Carey

    2017-12-01

    As human immunodeficiency virus (HIV) treatment programs expand in Africa, delivery systems must be strengthened to support patient retention. Clinic characteristics may affect retention, but a relationship between clinic flow and attrition is not established. This project characterized HIV patient experience and flow in an urban Kenyan clinic to understand how these may affect retention. We used Toyota's lean manufacturing principles to guide data collection and analysis. Clinic flow was evaluated using value stream mapping and time and motion techniques. Clinic register data were analyzed. Two focus group discussions were held to characterize HIV patient experience. Results were shared with clinic staff. Wait times in the clinic were highly variable. We identified four main barriers to patient flow: inconsistent patient arrivals, inconsistent staffing, filing system defects, and serving patients out of order. Focus group participants explained how clinic operations affected their ability to engage in care. Clinic staff were eager to discuss the problems identified and identified numerous low-cost potential solutions. Lean manufacturing methodologies can guide efficiency interventions in low-resource healthcare settings. Using lean techniques, we identified bottlenecks to clinic flow and low-cost solutions to improve wait times. Improving flow may result in increased patient satisfaction and retention.

  3. Special Issue on Time Scale Algorithms

    Science.gov (United States)

    2008-01-01

    unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 IOP PUBLISHING METROLOGIA Metrologia 45 (2008) doi:10.1088/0026-1394/45/6/E01...special issue of Metrologia presents selected papers from the Fifth International Time Scale Algorithm Symposium (VITSAS), including some of the...scientists, and hosted by the Real Instituto y Observatorio de la Armada (ROA) in San Fernando, Spain, whose staff further enhanced their nation’s high

  4. THE INFLUENCE OF WAITING TIME SATISFACTION ON CUSTOMER LOYALTY TOWARDS MULTI-STAGE SERVICES IN A FULL-SERVICE RESTAURANT: EVIDENCE FROM INDIA

    Directory of Open Access Journals (Sweden)

    A. Mittal

    2016-06-01

    Full Text Available Research shows waiting time in services is an important source of service evaluation by the customer. In fact, time is one component of the total 'cost' that the customer bears and cost is a core component of the perceived cost-benefit equation that the customer uses to evaluate her or his sustained patronage of a particular service. In most services, customers consider waiting as a waste of time. However, from the customer perspective, in the case of a full-service restaurant, waiting is expected and sometimes desirable also. Prior research, mainly in the west, suggests that when customers think that a wait for service is too long, they become less satisfied with overall service quality. Based on a research setting in a full-scale restaurant in India, this paper seeks answers to two research questions: First, what are the determinants of overall waiting-time satisfaction and second, what is the influence of waiting-time satisfaction on customer loyalty.

  5. Yet one more dwell time algorithm

    Science.gov (United States)

    Haberl, Alexander; Rascher, Rolf

    2017-06-01

    The current demand of even more powerful and efficient microprocessors, for e.g. deep learning, has led to an ongoing trend of reducing the feature size of the integrated circuits. These processors are patterned with EUV-lithography which enables 7 nm chips [1]. To produce mirrors which satisfy the needed requirements is a challenging task. Not only increasing requirements on the imaging properties, but also new lens shapes, such as aspheres or lenses with free-form surfaces, require innovative production processes. However, these lenses need new deterministic sub-aperture polishing methods that have been established in the past few years. These polishing methods are characterized, by an empirically determined TIF and local stock removal. Such a deterministic polishing method is ion-beam-figuring (IBF). The beam profile of an ion beam is adjusted to a nearly ideal Gaussian shape by various parameters. With the known removal function, a dwell time profile can be generated for each measured error profile. Such a profile is always generated pixel-accurately to the predetermined error profile, with the aim always of minimizing the existing surface structures up to the cut-off frequency of the tool used [2]. The processing success of a correction-polishing run depends decisively on the accuracy of the previously computed dwell-time profile. So the used algorithm to calculate the dwell time has to accurately reflect the reality. But furthermore the machine operator should have no influence on the dwell-time calculation. Conclusively there mustn't be any parameters which have an influence on the calculation result. And lastly it should take a minimum of machining time to get a minimum of remaining error structures. Unfortunately current dwell time algorithm calculations are divergent, user-dependent, tending to create high processing times and need several parameters to bet set. This paper describes an, realistic, convergent and user independent dwell time algorithm. The

  6. A "package solution" fast track program can reduce the diagnostic waiting time in head and neck cancer

    DEFF Research Database (Denmark)

    Sørensen, Jesper Roed; Johansen, Jørgen; Gano, Lars

    2014-01-01

    and Neck Surgery during three comparable time intervals 2006-2007, 2007-2008, and 2011-2012 (groups 1-3) were investigated. We recorded the time from patient referral, to first consultation and final diagnosis. The first interval was before initiation of the "package solution", the second just after......In 2007, a fast track program for patients with suspicion of head and neck cancer (HNC) was introduced in Denmark to reduce unnecessary waiting time. The program was based on so called "package solutions" including pre-booked slots for outpatient evaluation, imaging, and diagnostic surgical...... procedures. The purpose of this study is to present a model for fast track handling of patients suspicious of cancer in the head and neck region and to evaluate the effect of implementation on the diagnostic work up time. Patients with suspicion of HNC referred to the same university department of ENT Head...

  7. The effectiveness of service delivery initiatives at improving patients' waiting times in clinical radiology departments: a systematic review.

    Science.gov (United States)

    Olisemeke, B; Chen, Y F; Hemming, K; Girling, A

    2014-12-01

    We reviewed the literature for the impact of service delivery initiatives (SDIs) on patients' waiting times within radiology departments. We searched MEDLINE, EMBASE, CINAHL, INSPEC and The Cochrane Library for relevant articles published between 1995 and February, 2013. The Cochrane EPOC risk of bias tool was used to assess the risk of bias on studies that met specified design criteria. Fifty-seven studies met the inclusion criteria. The types of SDI implemented included extended scope practice (ESP, three studies), quality management (12 studies), productivity-enhancing technologies (PETs, 29 studies), multiple interventions (11 studies), outsourcing and pay-for-performance (one study each). The uncontrolled pre- and post-intervention and the post-intervention designs were used in 54 (95%) of the studies. The reporting quality was poor: many of the studies did not test and/or report the statistical significance of their results. The studies were highly heterogeneous, therefore meta-analysis was inappropriate. The following type of SDIs showed promising results: extended scope practice; quality management methodologies including Six Sigma, Lean methodology, and continuous quality improvement; productivity-enhancing technologies including speech recognition reporting, teleradiology and computerised physician order entry systems. We have suggested improved study design and the mapping of the definitions of patient waiting times in radiology to generic timelines as a starting point for moving towards a situation where it becomes less restrictive to compare and/or pool the results of future studies in a meta-analysis.

  8. Appointment waiting times and education level influence the quality of bowel preparation in adult patients undergoing colonoscopy

    Directory of Open Access Journals (Sweden)

    Goh Khean-Lee

    2011-07-01

    Full Text Available Abstract Background Risk factors for poor bowel preparation are recognized to be independent of the type of bowel preparation method used. Patient and administrative factors influencing bowel preparation are known to vary in different healthcare systems. Methods A prospective, cross-sectional study of patients undergoing colonoscopy in an Asian tertiary centre was conducted to identify risk factors associated with poor bowel preparation, and to evaluate the impact of poor bowel preparation on technical performance and patient comfort. Results Data on 501 patients (mean age 60.1 ± 14.0 years old, 51.2% males, 60.9% with secondary education or higher was available for analysis. Poor bowel preparation was present in 151 patients (30.1%. Lower education level (OR = 2.35, 95% CI = 1.54 - 3.60, colonoscopy appointment waiting time beyond 16 weeks (OR = 1.86, 95% CI = 1.04 - 3.37 and non-adherence to bowel preparation instructions (OR = 4.76, 95% CI = 3.00 - 7.55 were identified as independent risk factors for poor bowel preparation. Poor bowel preparation was associated with a lower cecal intubation rate (78.1% versus 98.3%, p Conclusions Education levels and appointment waiting times, in addition to non-adherence to bowel preparation instructions, increase the risk of poor bowel preparation in adult patients undergoing colonoscopy. The latter has a significant impact on colonoscopy performance and patient comfort.

  9. Fast algorithms for computing phylogenetic divergence time.

    Science.gov (United States)

    Crosby, Ralph W; Williams, Tiffani L

    2017-12-06

    The inference of species divergence time is a key step in most phylogenetic studies. Methods have been available for the last ten years to perform the inference, but the performance of the methods does not yet scale well to studies with hundreds of taxa and thousands of DNA base pairs. For example a study of 349 primate taxa was estimated to require over 9 months of processing time. In this work, we present a new algorithm, AncestralAge, that significantly improves the performance of the divergence time process. As part of AncestralAge, we demonstrate a new method for the computation of phylogenetic likelihood and our experiments show a 90% improvement in likelihood computation time on the aforementioned dataset of 349 primates taxa with over 60,000 DNA base pairs. Additionally, we show that our new method for the computation of the Bayesian prior on node ages reduces the running time for this computation on the 349 taxa dataset by 99%. Through the use of these new algorithms we open up the ability to perform divergence time inference on large phylogenetic studies.

  10. Whole body magnetic resonance in indolent lymphomas under watchful waiting. The time is now

    Energy Technology Data Exchange (ETDEWEB)

    Galia, Massimo; Albano, Domenico; Midiri, Massimo; Lagalla, Roberto [University of Palermo, Department of Radiology, Di.Bi.Med., Palermo (Italy); Tarella, Corrado [European Institute of Oncology, Hemato-Oncology Division, Milan (Italy); Patti, Caterina; Mule, Antonino [Azienda Ospedaliera Ospedali Riuniti Villa Sofia-Cervello, Department of Hematology I, Palermo (Italy); Sconfienza, Luca Maria [IRCCS Istituto Ortopedico Galeazzi, Unit of Diagnostic and Interventional Radiology, Milano (Italy); Universita degli Studi di Milano, Department of Biomedical Sciences for Health, Milano (Italy); Alongi, Pierpaolo [Fondazione Istituto G. Giglio, Contrada Pietrapollastra-Pisciotto, Department of Radiological Sciences, Nuclear Medicine Unit, Cefalu (Italy)

    2018-03-15

    The indolent non-Hodgkin lymphomas (i-NHLs) are characterised by 'indolent' clinical behaviour with slow growth and prolonged natural history. The watchful waiting (WW) strategy is a frequently employed treatment option in these patients. This implies a strict monitoring by imaging examinations, including 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (18F-FDG-PET/CT) and CT. A major concern is radiation exposure due to regularly monitoring by conventional imaging procedures. Several studies have demonstrated the reliability of whole-body magnetic resonance imaging (WB-MRI) for lymphoma staging. WB-MRI could be useful for active surveillance in i-NHLs providing the suspect of disease progression that can be then confirmed by additional diagnostic procedures, including 18F-FDG-PET/CT. The directive 2013/59 by the European Union claims that if a radiation-free imaging technique allows obtaining the same diagnostic results, it should be invariably used. In this setting, WB-MRI may be considered a reasonable option in i-NHLs under WW, replacing imaging modalities that cause exposure to ionising radiations. This will help to reduce the cancer risk in i-NHL patients for whom chemo-/radiotherapy remain the usual treatment options following the usually long WW phase. The scientific community should raise the awareness of the risk of ionising radiations in i-NHLs and the emphasise the need for establishing the proper place of WB-MRI in lymphoma imaging. (orig.)

  11. Estimating medication stopping fraction and real-time prevalence of drug use in pharmaco-epidemiologic databases. An application of the reverse waiting time distribution

    DEFF Research Database (Denmark)

    Støvring, Henrik; Pottegård, Anton; Hallas, Jesper

    2017-01-01

    Purpose: To introduce the reverse waiting time distribution (WTD) and show how it can be used to estimate stopping fractions and real-time prevalence of treatment in pharmacoepidemiological studies. Methods: The reverse WTD is the distribution of time from the last dispensed prescription of each......-hoc decision rules for automated implementations, and it yields estimates of real-time prevalence....... patient within a time window to the end of it. It is a mirrored version of the ordinary WTD, which considers the first dispensed prescription of patients within a time window. Based on renewal process theory, the reverse WTD can be analyzed as an ordinary WTD with maximum likelihood estimation. Based...

  12. Modeling the impact of integrating HIV and outpatient health services on patient waiting times in an urban health clinic in Zambia.

    Directory of Open Access Journals (Sweden)

    Sarang Deo

    Full Text Available Rapid scale up of HIV treatment programs in sub-Saharan Africa has refueled the long-standing health policy debate regarding the merits and drawbacks of vertical and integrated system. Recent pilots of integrating outpatient and HIV services have shown an improvement in some patient outcomes but deterioration in waiting times, which can lead to worse health outcomes in the long run.A pilot intervention involving integration of outpatient and HIV services in an urban primary care facility in Lusaka, Zambia was studied. Data on waiting time of patients during two seven-day periods before and six months after the integration were collected using a time and motion study. Statistical tests were conducted to investigate whether the two observation periods differed in operational details such as staffing, patient arrival rates, mix of patients etc. A discrete event simulation model was constructed to facilitate a fair comparison of waiting times before and after integration. The simulation model was also used to develop alternative configurations of integration and to estimate the resulting waiting times.Comparison of raw data showed that waiting times increased by 32% and 36% after integration for OPD and ART patients respectively (p<0.01. Using simulation modeling, we found that a large portion of this increase could be explained by changes in operational conditions before and after integration such as reduced staff availability (p<0.01 and longer breaks between consecutive patients (p<0.05. Controlling for these differences, integration of services, per se, would have resulted in a significant decrease in waiting times for OPD and a moderate decrease for HIV services.Integrating health services has the potential of reducing waiting times due to more efficient use of resources. However, one needs to ensure that other operational factors such as staff availability are not adversely affected due to integration.

  13. [Surgery for colorectal cancer since the introduction of the Netherlands national screening programmeInvestigations into changes in number of resections and waiting times for surgery].

    Science.gov (United States)

    de Neree Tot Babberich, M P M; van der Willik, E M; van Groningen, J T; Ledeboer, M; Wiggers, T; Wouters, M W J M

    2017-01-01

    To investigate the impact of the Netherlands national colorectal cancer screening programme on the number of surgical resections for colorectal carcinoma and on waiting times for surgery. Descriptive study. Data were extracted from the Dutch Surgical Colorectal Audit. Patients with primary colorectal cancer surgery between 2011-2015 were included. The volume and median waiting times for the years 2011-2015 are described. Waiting times from first tumor positive biopsy until the operation (biopsy-operation) and first preoperative visit to the surgeon until the operation (visit-operation) are analyzed with a univariate and multivariate linear regression analysis. Separate analysis was done for visit-operation for academic and non-academic hospitals and for screening compared to non-screening patients. In 2014 there was an increase of 1469 (15%) patients compared to 2013. In 2015 this increase consisted of 1168 (11%) patients compared to 2014. In 2014 and 2015, 1359 (12%) and 3111 (26%) patients were referred to the surgeon through screening, respectively. The median waiting time of biopsy-operation significantly decreased (ß: 0.94, 95%BI) over the years 2014-2015 compared to 2011-2013. In non-academic hospitals, the waiting time visit-operation also decreased significantly (ß: 0.89, 95%BI 0.87-0.90) over the years 2014-2015 compared to 2011-2013. No difference was found in waiting times between patients referred to the surgeon through screening compared to non-screening. There is a clear increase in volume since the introduction of the colorectal cancer screening programme without an increase in waiting time until surgery.

  14. The influence of deterministic and stochastic waiting time for triggering mortality and colonization events on the coexistence of cooperators and defectors in an evolutionary game model

    Directory of Open Access Journals (Sweden)

    YouHua Chen

    2014-06-01

    Full Text Available In the present report, the coexistence of Prisoners' Dilemma game players (cooperators and defectors were explored in an individual-based framework with the consideration of the impacts of deterministic and stochastic waiting time (WT for triggering mortality and/or colonization events. For the type of deterministic waiting time, the time step for triggering a mortality and/or colonization event is fixed. For the type of stochastic waiting time, whether a mortality and/or colonization event should be triggered for each time step of a simulation is randomly determined by a given acceptance probability (the event takes place when a variate drawn from a uniform distribution [0,1] is smaller than the acceptance probability. The two strategies of modeling waiting time are considered simultaneously and applied to both quantities (mortality: WTm, colonization: WTc. As such, when WT (WTm and/or WTc is an integral >=1, it indicated a deterministically triggering strategy. In contrast, when 1>WT>0, it indicated a stochastically triggering strategy and the WT value itself is used as the acceptance probability. The parameter space between the waiting time for mortality (WTm-[0.1,40] and colonization (WTc-[0.1,40] was traversed to explore the coexistence and non-coexistence regions. The role of defense award was evaluated. My results showed that, one non-coexistence region is identified consistently, located at the area where 1>=WTm>=0.3 and 40>=WTc>=0.1. As a consequence, it was found that the coexistence of cooperators and defectors in the community is largely dependent on the waiting time of mortality events, regardless of the defense or cooperation rewards. When the mortality events happen in terms of stochastic waiting time (1>=WTm>=0.3, extinction of either cooperators or defectors or both could be very likely, leading to the emergence of non-coexistence scenarios. However, when the mortality events occur in forms of relatively long deterministic

  15. Evaluating wait times from screening to breast cancer diagnosis among women undergoing organised assessment vs usual care.

    Science.gov (United States)

    Chiarelli, Anna M; Muradali, Derek; Blackmore, Kristina M; Smith, Courtney R; Mirea, Lucia; Majpruz, Vicky; O'Malley, Frances P; Quan, May Lynn; Holloway, Claire Mb

    2017-05-09

    Timely coordinated diagnostic assessment following an abnormal screening mammogram reduces patient anxiety and may optimise breast cancer prognosis. Since 1998, the Ontario Breast Screening Program (OBSP) has offered organised assessment through Breast Assessment Centres (BACs). For OBSP women seen at a BAC, an abnormal mammogram is followed by coordinated referrals through the use of navigators for further imaging, biopsy, and surgical consultation as indicated. For OBSP women seen through usual care (UC), further diagnostic imaging is arranged directly from the screening centre and/or through their physician; results must be communicated to the physician who is then responsible for arranging any necessary biopsy and/or surgical consultation. This study aims to evaluate factors associated with diagnostic wait times for women undergoing assessment through BAC and UC. Of the 2 147 257 women aged 50-69 years screened in the OBSP between 1 January 2002 and 31 December 2009, 155 866 (7.3%) had an abnormal mammogram. A retrospective design identified two concurrent cohorts of women diagnosed with screen-detected breast cancer at a BAC (n=4217; 47%) and UC (n=4827; 53%). Multivariable logistic regression analyses examined associations between wait times and assessment and prognostic characteristics by pathway. A two-sided 5% significance level was used. Screened women with breast cancer were two times more likely to be diagnosed within 7 weeks when assessed through a BAC vs UC (OR=1.91, 95% CI=1.73-2.10). In addition, compared with UC, women assessed through a BAC were significantly more likely to have their first assessment procedure within 3 weeks of their abnormal mammogram (OR=1.25, 95% CI=1.12-1.39), ⩽3 assessment procedures (OR=1.54, 95% CI=1.41-1.69), ⩽2 assessment visits (OR=1.86, 95% CI=1.70-2.05), and ⩾2 procedures per visit (OR=1.41, 95% CI=1.28-1.55). Women diagnosed through a BAC were also more likely than those in UC to have imaging (OR=1.99, 95

  16. EDITORIAL: Special issue on time scale algorithms

    Science.gov (United States)

    Matsakis, Demetrios; Tavella, Patrizia

    2008-12-01

    This special issue of Metrologia presents selected papers from the Fifth International Time Scale Algorithm Symposium (VITSAS), including some of the tutorials presented on the first day. The symposium was attended by 76 persons, from every continent except Antarctica, by students as well as senior scientists, and hosted by the Real Instituto y Observatorio de la Armada (ROA) in San Fernando, Spain, whose staff further enhanced their nation's high reputation for hospitality. Although a timescale can be simply defined as a weighted average of clocks, whose purpose is to measure time better than any individual clock, timescale theory has long been and continues to be a vibrant field of research that has both followed and helped to create advances in the art of timekeeping. There is no perfect timescale algorithm, because every one embodies a compromise involving user needs. Some users wish to generate a constant frequency, perhaps not necessarily one that is well-defined with respect to the definition of a second. Other users might want a clock which is as close to UTC or a particular reference clock as possible, or perhaps wish to minimize the maximum variation from that standard. In contrast to the steered timescales that would be required by those users, other users may need free-running timescales, which are independent of external information. While no algorithm can meet all these needs, every algorithm can benefit from some form of tuning. The optimal tuning, and even the optimal algorithm, can depend on the noise characteristics of the frequency standards, or of their comparison systems, the most precise and accurate of which are currently Two Way Satellite Time and Frequency Transfer (TWSTFT) and GPS carrier phase time transfer. The interest in time scale algorithms and its associated statistical methodology began around 40 years ago when the Allan variance appeared and when the metrological institutions started realizing ensemble atomic time using more than

  17. Waiting experience in railway environments

    NARCIS (Netherlands)

    van Hagen, M.; Galetzka, Mirjam; Pruyn, Adriaan T.H.

    2014-01-01

    At railway stations, waiting time is usually an unavoidable aspect of the journey for train passengers. According to the attentional model of time, pleasant surroundings and other forms of distraction reduce perceived waiting time. Not every individual reacts identically in the same surroundings.

  18. Improvement in Obstructive Sleep Apnea Diagnosis and Management Wait Times: A Retrospective Analysis of a Home Management Pathway for Obstructive Sleep Apnea

    Directory of Open Access Journals (Sweden)

    Samuel Alan Stewart

    2015-01-01

    Full Text Available Obstructive sleep apnea is a common condition within the Canadian population. The current gold standard for diagnosis and management of patients is in-laboratory (in-lab polysomnography; however, the limited availability of testing options for patients has led to long wait times and increased disease burden within the population. The Sleep Research Laboratory in Saskatoon (Saskatchewan implemented a home management program to run in parallel with the in-lab system several years ago in an effort to increase their capacity and reduce wait times. The present study was a retrospective analysis of all patients referred to the program between 2009 and 2012. The home management system has improved wait times by diagnosing and managing up to one-half of the referred patient population, reducing the wait for in-lab treatment from a median of 152 days in 2009 to 92 days in 2012 (P<0.0001. Moving forward, home management can provide a viable alternative to in-lab testing for patients who meet strict entry criteria, reducing the in-lab workload and, ultimately, reducing wait times.

  19. The effects of feeding frequency on waiting time, milking frequency, cubicle and feeding fence utilization for cows in an automatic milking system

    NARCIS (Netherlands)

    Oostra, H.H.; Stefanowska, J.; Sallvik, K.

    2005-01-01

    In this trial, the effects of the forage feeding frequency on the waiting time prior to milking and the cowshed facility utilization by cows milked in an automatic milking unit (AMU) were studied. The feeding frequency was increased from two times per day to six times per day. It was found that the

  20. Improving case-based reasoning systems by combining k-nearest neighbour algorithm with logistic regression in the prediction of patients' registration on the renal transplant waiting list.

    Directory of Open Access Journals (Sweden)

    Boris Campillo-Gimenez

    Full Text Available Case-based reasoning (CBR is an emerging decision making paradigm in medical research where new cases are solved relying on previously solved similar cases. Usually, a database of solved cases is provided, and every case is described through a set of attributes (inputs and a label (output. Extracting useful information from this database can help the CBR system providing more reliable results on the yet to be solved cases.We suggest a general framework where a CBR system, viz. K-Nearest Neighbour (K-NN algorithm, is combined with various information obtained from a Logistic Regression (LR model, in order to improve prediction of access to the transplant waiting list.LR is applied, on the case database, to assign weights to the attributes as well as the solved cases. Thus, five possible decision making systems based on K-NN and/or LR were identified: a standalone K-NN, a standalone LR and three soft K-NN algorithms that rely on the weights based on the results of the LR. The evaluation was performed under two conditions, either using predictive factors known to be related to registration, or using a combination of factors related and not related to registration.The results show that our suggested approach, where the K-NN algorithm relies on both weighted attributes and cases, can efficiently deal with non relevant attributes, whereas the four other approaches suffer from this kind of noisy setups. The robustness of this approach suggests interesting perspectives for medical problem solving tools using CBR methodology.

  1. Polling Systems with Two-Phase Gated Service: Heavy Traffic Results for the Waiting Time Distribution

    NARCIS (Netherlands)

    R.D. van der Mei (Rob); J.A.C. Resing

    2008-01-01

    htmlabstractWe study an asymmetric cyclic polling system with Poisson arrivals, general service-time and switch-over time distributions, and with so-called two-phase gated service at each queue, an interleaving scheme that aims to enforce some level of "fairness" among the different customer

  2. A probabilistic model for estimating the waiting time until the simultaneous collapse of two contingencies

    International Nuclear Information System (INIS)

    Barnett, C.S.

    1991-01-01

    The Double Contingency Principle (DCP) is widely applied to criticality safety practice in the United States. Most practitioners base their application of the principle on qualitative, intuitive assessments. The recent trend toward probabilistic safety assessments provides a motive to search for a quantitative, probabilistic foundation for the DCP. A Markov model is tractable and leads to relatively simple results. The model yields estimates of mean time to simultaneous collapse of two contingencies as a function of estimates of mean failure times and mean recovery times of two independent contingencies. The model is a tool that can be used to supplement the qualitative methods now used to assess effectiveness of the DCP. (Author)

  3. Commercial border crossing and wait time measurement at the Pharr-Reynosa International Bridge.

    Science.gov (United States)

    2010-11-01

    The objective of the research described in this report is to install and implement radio frequency : identification (RFID) technology to measure border crossing time and travel delay for : commercial trucks crossing from Mexico into Texas at the Phar...

  4. An explicit solution for a renewal process with waiting time and its variational principle

    International Nuclear Information System (INIS)

    Lewins, J.D.

    2001-01-01

    The forward and backward equations for the conditional probability density are derived for a reliability system consisting of a single component whose repair is subject to a delay time in providing a spare part but whose mean rate of repair is otherwise constant and whose time to failure is exponentially distributed. Exact solutions are quoted. These equations are then shown to be an adjoint pair that provide stationary conditions for a variational principle, in elementary form, from which all properties of the systems can be predicted with an accuracy greater than that implied by the trial functions or approximations used. A second or specific form of variational principle provides specific estimates to questions at hand. The second or adjoint field in the first elementary principle is the backward Kolmogorov solution and the in the specific form is the importance function, as used in nuclear reactor theory. The solutions are given for long-time and in a recurrence relation form valid for all times so that approximate solutions can be checked. Approximations suitable for variational trial functions are given. Two examples give the effect of a change of delay time for a steady state and an initial transient, respectively

  5. A probabilistic model for estimating the waiting time until the simultaneous collapse of two contingencies

    International Nuclear Information System (INIS)

    Barnett, C.S.

    1991-06-01

    The Double Contingency Principle (DCP) is widely applied to criticality safety practice in the United States. Most practitioners base their application of the principle on qualitative, intuitive assessments. The recent trend toward probabilistic safety assessments provides a motive to search for a quantitative, probabilistic foundation for the DCP. A Markov model is tractable and leads to relatively simple results. The model yields estimates of mean time to simultaneous collapse of two contingencies as a function of estimates of mean failure times and mean recovery times of two independent contingencies. The model is a tool that can be used to supplement the qualitative methods now used to assess effectiveness of the DCP. 3 refs., 1 fig

  6. A probabilistic model for estimating the waiting time until the simultaneous collapse of two contingencies

    International Nuclear Information System (INIS)

    Barnett, C.S.

    1992-01-01

    The double contingency principle (DCP) is widely applied to criticality safety practice in the United States. Most practitioners base their application of the principle on qualitative and intuitive assessments. The recent trend toward probabilistic safety assessments provides a motive for a search for a quantitative and probabilistic foundation for the DCP. A Markov model is tractable and leads to relatively simple results. The model yields estimates of mean time to simultaneous collapse of two contingencies, as functions of estimates of mean failure times and mean recovery times of two independent contingencies. The model is a tool that can be used to supplement the qualitative methods now used to assess the effectiveness of the DCP. (Author)

  7. Deficient neural activity subserving decision-making during reward waiting time in intertemporal choice in adult attention-deficit hyperactivity disorder.

    Science.gov (United States)

    Todokoro, Ayako; Tanaka, Saori C; Kawakubo, Yuki; Yahata, Noriaki; Ishii-Takahashi, Ayaka; Nishimura, Yukika; Kano, Yukiko; Ohtake, Fumio; Kasai, Kiyoto

    2018-04-24

    Impulsivity, which significantly affects social adaptation, is an important target behavioral characteristic in interventions for attention-deficit hyperactivity disorder (ADHD). Typically, people are willing to wait longer to acquire greater rewards. Impulsivity in ADHD may be associated with brain dysfunction in decision-making involving waiting behavior under such situations. We tested the hypothesis that brain circuitry during a period of waiting (i.e., prior to the acquisition of reward) is altered in adults with ADHD. The participants included 14 medication-free adults with ADHD and 16 healthy controls matched for age, sex, IQ, and handedness. The behavioral task had participants choose between a delayed, larger monetary reward and an immediate, smaller monetary reward, where the reward waiting time actually occurred during functional magnetic resonance imaging measurement. We tested for group differences in the contrast values of blood-oxygen-level dependent signals associated with the length of waiting time, calculated using the parametric modulation method. While the two groups did not differ in the time discounting rate, the delay-sensitive contrast values were significantly lower in the caudate and visual cortex in individuals with ADHD. The higher impulsivity scores were significantly associated with lower delay-sensitive contrast values in the caudate and visual cortex. These results suggest that deficient neural activity affects decision-making involving reward waiting time during intertemporal choice tasks, and provide an explanation for the basis of impulsivity in adult ADHD. © 2018 The Author. Psychiatry and Clinical Neurosciences © 2018 Japanese Society of Psychiatry and Neurology.

  8. The customer waiting time in an (R,s,Q) inventory system

    NARCIS (Netherlands)

    Kiesmüller, G.P.; Kok, de A.G.

    2006-01-01

    In practice of inventory management customer-oriented service measures play an important role. If inventory managers of stockpoints in a supply chain promise specific times of delivery that cannot be met due to a lack of stock, leadtimes at downstream stockpoints increase, causing substantial

  9. Real-Time Wait-Free Queues using Micro-Transactions

    OpenAIRE

    Meawad, Fadi; Iyer, Karthik; Schoeberl, Martin; Vitek, Jan

    2011-01-01

    This paper evaluates the applicability of transactional mem- ory to the implementation of dierent non-blocking data structures in the context of the Real-time Specication for Java. In particular, we argue that hardware support for micro-transaction allows us to implement eciently data structures that are often dicult to realize with the atomic operations provided by stock hardware. Our main imple- mentation platform is the Java Optimized Processor sys- tem. We report on the performance of dat...

  10. Waiting for the Unicorn: Perception of Time and History in Early Chinese Writings

    OpenAIRE

    Gibas, Piotr Pawel

    2009-01-01

    In this dissertation I examine temporality as conceived in early Chinese historiography, through a systematic examination of four key works: the Mozi, the Zuozhuan, the Rishu;, and the Chu Silk Manuscript, all of them written during 4th through 1st century BCE. Each presents from a different perspective ideas about the mechanism of time and history. While only the Zuozhuan is commonly categorized as historical narrative, all four of these texts depend on records of the past to convey their wo...

  11. Real-Time Wait-Free Queues using Micro-Transactions

    DEFF Research Database (Denmark)

    Meawad, Fadi; Iyer, Karthik; Schoeberl, Martin

    2011-01-01

    This paper evaluates the applicability of transactional mem- ory to the implementation of dierent non-blocking data structures in the context of the Real-time Specication for Java. In particular, we argue that hardware support for micro-transaction allows us to implement eciently data structures...... that are often dicult to realize with the atomic operations provided by stock hardware. Our main imple- mentation platform is the Java Optimized Processor sys- tem. We report on the performance of data structures imple- mented with locks, compare and swap and micro-transactions. Our results conrm...

  12. Waiting time to radiotherapy as a prognostic factor for glioblastoma patients in a scenario of medical disparities

    Energy Technology Data Exchange (ETDEWEB)

    Loureiro, Luiz Victor Maia; Callegaro-Filho, Donato; Koch, Ludmila de Oliveira; Weltman, Eduardo; Victor, Elivane da Silva; Malheiros, Suzana Maria Fleury, E-mail: lvmaia@gmail.com [Hospital Israelita Albert Einstein, Sao Paulo, SP (Brazil); Santos, Adrialdo Jose; Borges, Lia Raquel Rodrigues; Segreto, Roberto Araujo [Universidade Federal de Sao Paulo (UNIFESP), Sao Paulo, SP (Brazil). Escola paulista de Medicina; Pontes, Luciola de Barros [Hospital do Coracao, Sao Paulo, SP (Brazil). Dept. de Oncologia

    2015-02-15

    Objective: to evaluate the effect of waiting time (WT) to radiotherapy (RT) on overall survival (OS) of glioblastoma (GBM) patients as a reliable prognostic variable in Brazil, a scenario of medical disparities. Method: retrospective study of 115 GBM patients from two different health-care institutions (one public and one private) in Brazil who underwent post-operative RT. Results: Median WT to RT was 6 weeks (range,1.3-17.6). The median OS for WT ≤ 6 weeks was 13.5 months (95%CI , 9.1-17.9) and for WT . 6 weeks was 14.2 months (95%CI, 11.2-17.2) (HR 1.165, 95%CI 0.770-1.762; p = 0.470). In the multivariate analysis, the variables associated with survival were KPS (p , 0.001), extent of resection (p = 0.009) and the adjuvant treatment (p = 0.001). The KPS interacted with WT to RT (HR 0.128, 95%CI 0.034-0.476; p = 0.002), showing that the benefit of KPS on OS depends on the WT to RT. Conclusion: no prognostic impact of WT to RT could be detected on the OS. Although there are no data to ensure that delays to RT are tolerable, we may reassure patients that the time-length to initiate treatment does not seem to influence the control of the disease, particularly in face of other prognostic factors. (author)

  13. An explicit multi-time-stepping algorithm for aerodynamic flows

    NARCIS (Netherlands)

    Niemann-Tuitman, B.E.; Veldman, A.E.P.

    1997-01-01

    An explicit multi-time-stepping algorithm with applications to aerodynamic flows is presented. In the algorithm, in different parts of the computational domain different time steps are taken, and the flow is synchronized at the so-called synchronization levels. The algorithm is validated for

  14. Continuous Time Dynamic Contraflow Models and Algorithms

    Directory of Open Access Journals (Sweden)

    Urmila Pyakurel

    2016-01-01

    Full Text Available The research on evacuation planning problem is promoted by the very challenging emergency issues due to large scale natural or man-created disasters. It is the process of shifting the maximum number of evacuees from the disastrous areas to the safe destinations as quickly and efficiently as possible. Contraflow is a widely accepted model for good solution of evacuation planning problem. It increases the outbound road capacity by reversing the direction of roads towards the safe destination. The continuous dynamic contraflow problem sends the maximum number of flow as a flow rate from the source to the sink in every moment of time unit. We propose the mathematical model for the continuous dynamic contraflow problem. We present efficient algorithms to solve the maximum continuous dynamic contraflow and quickest continuous contraflow problems on single source single sink arbitrary networks and continuous earliest arrival contraflow problem on single source single sink series-parallel networks with undefined supply and demand. We also introduce an approximation solution for continuous earliest arrival contraflow problem on two-terminal arbitrary networks.

  15. Using business process redesign to reduce wait times at a university hospital in the Netherlands.

    Science.gov (United States)

    Elkhuizen, Sylvia G; Burger, Matthe P M; Jonkers, Rene E; Limburg, Martien; Klazinga, Niek; Bakker, Piet J M

    2007-06-01

    Business process redesign (BPR) has been applied to implement more customer-focused and cost-effective care. In 2002, two pilot projects to improve patient care processes for two specific patient groups were conducted at the Academic Medical Center, a 1,000-bed university hospital in Amsterdam. The BPR consisted of process analysis, identification of bottlenecks and goals for redesign, selection of interventions, and evaluation of effects. After identifying and selecting interventions with the greatest expected benefits, changes were implemented and effects were evaluated. For gynecologic oncology patients, access time (from telephone call to first visit) was reduced from 14 days to changes in communication and planning were sufficient to eliminate bottlenecks in the gynecologic oncology project, the dyspnea project required a radical redesign of processes. Experience since these projects suggests that process redesign may have only marginal impact when the greatest bottleneck occurs, as was the case for the two BPR projects, at the point of access to central diagnostic facilities.

  16. Sorting on STAR. [CDC computer algorithm timing comparison

    Science.gov (United States)

    Stone, H. S.

    1978-01-01

    Timing comparisons are given for three sorting algorithms written for the CDC STAR computer. One algorithm is Hoare's (1962) Quicksort, which is the fastest or nearly the fastest sorting algorithm for most computers. A second algorithm is a vector version of Quicksort that takes advantage of the STAR's vector operations. The third algorithm is an adaptation of Batcher's (1968) sorting algorithm, which makes especially good use of vector operations but has a complexity of N(log N)-squared as compared with a complexity of N log N for the Quicksort algorithms. In spite of its worse complexity, Batcher's sorting algorithm is competitive with the serial version of Quicksort for vectors up to the largest that can be treated by STAR. Vector Quicksort outperforms the other two algorithms and is generally preferred. These results indicate that unusual instruction sets can introduce biases in program execution time that counter results predicted by worst-case asymptotic complexity analysis.

  17. Impact of diagnosis-to-treatment waiting time on survival in esophageal cancer patients – A population-based study in The Netherlands

    NARCIS (Netherlands)

    Visser, E.; van Rossum, P.S.N.; Leeftink, Anne Greetje; Siesling, Sabine; van Hillegersberg, R.; Ruurda, J.P.

    Background The aim of this study was to determine whether the waiting time from diagnosis to treatment with curative intent for esophageal cancer impacts oncologic outcomes. Patients and methods All patients treated by esophagectomy for esophageal carcinoma in 2005–2013 were identified from the

  18. The Effect of the Transition to Home Monitoring for the Diagnosis of OSAS on Test Availability, Waiting Time, Patients’ Satisfaction, and Outcome in a Large Health Provider System

    Directory of Open Access Journals (Sweden)

    Ahmad Safadi

    2014-01-01

    Full Text Available During 2009, the Haifa district of Clalit Health Services (CHS has switched from in-lab polysomnography (PSG to home studies for the diagnosis of obstructive sleep apnea (OSA. We assessed the effects of this change on accessibility, waiting time, satisfaction, costs, and CPAP purchase by the patients. Data regarding sleep studies, CPAP purchase, and waiting times were collected retrospectively from the computerized database of CHS. Patients’ satisfaction was assessed utilizing a telephone questionnaire introduced to a randomized small sample of 70 patients. Comparisons were made between 2007 and 2008 (in-lab PSGs and 2010 and 2011 (when most studies were ambulatory. Of about 650000 insured individuals in the Haifa district of CHS, 1471 sleep studies were performed during 2007-2008 compared to 2794 tests during 2010-2011. The average waiting time was 9.9 weeks in 2007-2008 compared to 1.1 weeks in 2010-2011 (P<0.05. 597 CPAPs were purchased in 2007-2008 compared to 831 in 2010-2011. The overall patients’ satisfaction was similar, but discomfort tended to be higher in the in-laboratory group (4.1 vs 2.7 in a scale of 0–10; P=0.11. Switching to ambulatory diagnosis improved the test accessibility and reduced the waiting times. Patients’ satisfaction remained similarly high. The total direct cost of OSA management was reduced.

  19. The relationship between waiting times and 'adherence' to the Scottish Intercollegiate Guidelines Network 98 guideline in autism spectrum disorder diagnostic services in Scotland.

    Science.gov (United States)

    McKenzie, Karen; Forsyth, Kirsty; O'Hare, Anne; McClure, Iain; Rutherford, Marion; Murray, Aja; Irvine, Linda

    2016-05-01

    The aim of this study was to explore the extent to which the Scottish Intercollegiate Guidelines Network 98 guidelines on the assessment and diagnosis of autism spectrum disorder were adhered to in child autism spectrum disorder diagnostic services in Scotland and whether there was a significant relationship between routine practice which more closely reflected these recommendations (increased adherence) and increased waiting times. Retrospective, cross-sectional case note analysis was applied to data from 80 case notes. Adherence ranged from a possible 0 (no adherence) to 19 (full adherence). Overall, 17/22 of the recommendations were adhered to in over 50 of the 80 cases and in 70 or more cases for 11/22 of the recommendations, with a mean adherence score of 16 (standard deviation = 1.9). No significant correlation was found between adherence and total wait time for untransformed (r = 0.15, p = 0.32) or transformed data (r = 0.12, p = 0.20). The results indicated that the assessment and diagnostic practices were consistent with the relevant Scottish Intercollegiate Guidelines Network 98 guideline recommendations. Increased adherence to the 19 included recommendations was not significantly related to increased total waiting times, indicating that the Scottish Intercollegiate Guidelines Network 98 recommendations have generally been integrated into practice, without a resultant increase in patient waits. © The Author(s) 2015.

  20. Weighing waiting

    Directory of Open Access Journals (Sweden)

    Samuel M. Duncan

    2007-12-01

    Full Text Available People have been shown to delay decision making to wait for missing noninstrumental attribute information --- information that would not have altered their decision if known at the outset --- with this delay originally attributed to uncertainty obscuring one's true preference (Bastardi and Shafir, 1998. To test this account, relative to an alternative that delay arises from low confidence in one's preference (Tykocinski and Ruffle, 2003, we manipulated information certainty and the magnitude of a penalty for delay, the latter intended to reduce the influence of easily resolved sources of delay and to magnify any influence of uncertainty. Contrary to expectations, the results were largely inconsistent with the uncertainty account in that, under a low penalty, delay did not depend on information certainty; and, under a high penalty, delay rate was actually much lower when information was uncertain. To explain the latter, we propose that people use a strategy for resolving choice under uncertainty that does not require establishing a confident preference for each value of the missing information. These findings are related to others in which choice difficulty has been found to be a major source of delay.

  1. Waiting time - an offence?

    DEFF Research Database (Denmark)

    Ludvigsen, Mette Spliid

    2004-01-01

    The purpose of the original study: Patient-culture - a qualitative study among hospitalised patients, which is inspired by the work of Album and Isaksen, is to discover, and describe patients' experiences of informal relations and interpret the meaning of having fellow-patients during hospitalisa......The purpose of the original study: Patient-culture - a qualitative study among hospitalised patients, which is inspired by the work of Album and Isaksen, is to discover, and describe patients' experiences of informal relations and interpret the meaning of having fellow-patients during...... fieldwork is set up consisting of participant observation and interviews.   Based on the qualitative analysis completed to date on a data set consisting of field notes from participant observations and informal interviews I explore patients' social interactions in their day-to-day lives on two adult...

  2. Algorithms for Brownian first-passage-time estimation

    Science.gov (United States)

    Adib, Artur B.

    2009-09-01

    A class of algorithms in discrete space and continuous time for Brownian first-passage-time estimation is considered. A simple algorithm is derived that yields exact mean first-passage times (MFPTs) for linear potentials in one dimension, regardless of the lattice spacing. When applied to nonlinear potentials and/or higher spatial dimensions, numerical evidence suggests that this algorithm yields MFPT estimates that either outperform or rival Langevin-based (discrete time and continuous space) estimates.

  3. An algorithm for learning real-time automata

    NARCIS (Netherlands)

    Verwer, S.E.; De Weerdt, M.M.; Witteveen, C.

    2007-01-01

    We describe an algorithm for learning simple timed automata, known as real-time automata. The transitions of real-time automata can have a temporal constraint on the time of occurrence of the current symbol relative to the previous symbol. The learning algorithm is similar to the redblue fringe

  4. Saving time in a space-efficient simulation algorithm

    NARCIS (Netherlands)

    Markovski, J.

    2011-01-01

    We present an efficient algorithm for computing the simulation preorder and equivalence for labeled transition systems. The algorithm improves an existing space-efficient algorithm and improves its time complexity by employing a variant of the stability condition and exploiting properties of the

  5. A Dynamic Fuzzy Cluster Algorithm for Time Series

    Directory of Open Access Journals (Sweden)

    Min Ji

    2013-01-01

    clustering time series by introducing the definition of key point and improving FCM algorithm. The proposed algorithm works by determining those time series whose class labels are vague and further partitions them into different clusters over time. The main advantage of this approach compared with other existing algorithms is that the property of some time series belonging to different clusters over time can be partially revealed. Results from simulation-based experiments on geographical data demonstrate the excellent performance and the desired results have been obtained. The proposed algorithm can be applied to solve other clustering problems in data mining.

  6. An Efficient Randomized Algorithm for Real-Time Process Scheduling in PicOS Operating System

    Science.gov (United States)

    Helmy*, Tarek; Fatai, Anifowose; Sallam, El-Sayed

    PicOS is an event-driven operating environment designed for use with embedded networked sensors. More specifically, it is designed to support the concurrency in intensive operations required by networked sensors with minimal hardware requirements. Existing process scheduling algorithms of PicOS; a commercial tiny, low-footprint, real-time operating system; have their associated drawbacks. An efficient, alternative algorithm, based on a randomized selection policy, has been proposed, demonstrated, confirmed for efficiency and fairness, on the average, and has been recommended for implementation in PicOS. Simulations were carried out and performance measures such as Average Waiting Time (AWT) and Average Turn-around Time (ATT) were used to assess the efficiency of the proposed randomized version over the existing ones. The results prove that Randomized algorithm is the best and most attractive for implementation in PicOS, since it is most fair and has the least AWT and ATT on average over the other non-preemptive scheduling algorithms implemented in this paper.

  7. An explicit multi-time-stepping algorithm for aerodynamic flows

    OpenAIRE

    Niemann-Tuitman, B.E.; Veldman, A.E.P.

    1997-01-01

    An explicit multi-time-stepping algorithm with applications to aerodynamic flows is presented. In the algorithm, in different parts of the computational domain different time steps are taken, and the flow is synchronized at the so-called synchronization levels. The algorithm is validated for aerodynamic turbulent flows. For two-dimensional flows speedups in the order of five with respect to single time stepping are obtained.

  8. Waiting for surgery: is waiting bad for anyone or everyone?

    Science.gov (United States)

    Sutherland, J M; Liu, G; Crump, R T; Karimuddin, A A

    2017-12-01

    For Canadians, as in many countries, waiting for elective surgery is expected. The duration of the wait raises questions about the maximum amount of time patients should wait for their surgery. The primary objective of this study was to test for a relationship between the length of time patients waited for elective hernia repair surgery and change in patients' self-reported health. This study was based on a prospectively recruited longitudinal cohort of patients waiting for elective hernia repair surgery. Participants completed the PHQ-9, PEG, EQ-5D(3L) generic instruments, and the condition-specific COMI-hernia. Multivariate regression models explored associations between patient-reported outcomes and potential confounders, including age, sex, socio-economic status, and medical comorbidities. There were 118 participants and the modal age group was 61-70 years. The average wait time for participants was 22.5 weeks. There were no relationships between the duration of participants' wait for hernia repair and the change in patients' self-reported health for hernia-specific outcomes or overall health-related quality of life. There are gains in health-related quality of life to be realized by prioritizing symptomatic patients. Participants with greater pre-operative depression, pain, and hernia-related symptoms experienced an improvement in health prior to surgery, though more clarity is needed on the mechanisms that led to improved health. Many countries face problems with wait lists for elective surgery-and few have effective processes for triaging patients. This study shows that duration of time on the wait list was not associated with change in hernia patients' self-reported health.

  9. Effectiveness of firefly algorithm based neural network in time series ...

    African Journals Online (AJOL)

    Effectiveness of firefly algorithm based neural network in time series forecasting. ... In the experiments, three well known time series were used to evaluate the performance. Results obtained were compared with ... Keywords: Time series, Artificial Neural Network, Firefly Algorithm, Particle Swarm Optimization, Overfitting ...

  10. ¿Ha llegado la hora de la gestión de las listas de espera? Has the time arrived for the management of waiting lists?

    Directory of Open Access Journals (Sweden)

    E. Bernal

    2002-10-01

    Full Text Available Las personas que ocupan una lista de espera sufren a menudo un riesgo adicional derivado del tiempo que pasa hasta que obtienen tratamiento; sin embargo, en otras ocasiones, las personas en lista no tienen necesidad del tratamiento por el que esperan. Ambos argumentos, contrastables con evidencias empíricas, serían suficientes para afirmar que debe llegar la gestión a las listas de espera dejando a un lado políticas más o menos oportunistas. Por políticas oportunistas se entiende mantener la mala información sobre listas o su "maquillaje", utilizar programas de autoconcertación sin más horizonte que llegar a final de año sin lista de más de seis meses, etcétera. El panorama no es del todo oscuro. Algunas iniciativas de gestión (incluso de Política con mayúscula se van abriendo paso y pueden entrar en la agenda de los próximos años. Así, cabe destacar la aplicación de tiempos de atención garantizada o la priorización de las listas en función de criterios explícitos. En todo caso, conviene recordar que, con la excepción de las colas producidas en las salas de espera de los centros de salud y aquéllas que se producen en las puertas de urgencias, el resto de colas del sistema están mediadas por la decisión de un médico. Así que una estrategia ineludible para gestionar las listas de espera consiste en atenuar los problemas derivados de la incertidumbre (o ignorancia con respecto al diagnóstico o al pronóstico de los pacientes.Individuals on the waiting list frequently suffer an additional risk caused by the mean time until they receive treatment; however, other individuals do not need the treatment for which they are waiting. Both arguments, which can be contrasted with empirical evidence, would be sufficient to affirm that waiting list management should be implemented, leaving aside policies that are more of less opportunistic. Opportunistic policies are understood as those providing misinformation on waiting lists or

  11. Distributed Time Synchronization Algorithms and Opinion Dynamics

    Science.gov (United States)

    Manita, Anatoly; Manita, Larisa

    2018-01-01

    We propose new deterministic and stochastic models for synchronization of clocks in nodes of distributed networks. An external accurate time server is used to ensure convergence of the node clocks to the exact time. These systems have much in common with mathematical models of opinion formation in multiagent systems. There is a direct analogy between the time server/node clocks pair in asynchronous networks and the leader/follower pair in the context of social network models.

  12. Time-Delay System Identification Using Genetic Algorithm

    DEFF Research Database (Denmark)

    Yang, Zhenyu; Seested, Glen Thane

    2013-01-01

    Due to the unknown dead-time coefficient, the time-delay system identification turns to be a non-convex optimization problem. This paper investigates the identification of a simple time-delay system, named First-Order-Plus-Dead-Time (FOPDT), by using the Genetic Algorithm (GA) technique. The qual......Due to the unknown dead-time coefficient, the time-delay system identification turns to be a non-convex optimization problem. This paper investigates the identification of a simple time-delay system, named First-Order-Plus-Dead-Time (FOPDT), by using the Genetic Algorithm (GA) technique...

  13. Energy conservation in Newmark based time integration algorithms

    DEFF Research Database (Denmark)

    Krenk, Steen

    2006-01-01

    Energy balance equations are established for the Newmark time integration algorithm, and for the derived algorithms with algorithmic damping introduced via averaging, the so-called a-methods. The energy balance equations form a sequence applicable to: Newmark integration of the undamped equations...... of motion, an extended form including structural damping, and finally the generalized form including structural as well as algorithmic damping. In all three cases the expression for energy, appearing in the balance equation, is the mechanical energy plus some additional terms generated by the discretization...

  14. Consumer behaviour in the waiting area.

    Science.gov (United States)

    Mobach, Mark P

    2007-02-01

    To determine consumer behaviour in the pharmacy waiting area. The applied methods for data-collection were direct observations. Three Dutch community pharmacies were selected for the study. The topics in the observation list were based on available services at each waiting area (brochures, books, illuminated new trailer, children's play area, etc.). Per patient each activity was registered, and at each pharmacy the behaviour was studied for 2 weeks. Most patients only waited during the waiting time at the studied pharmacies. Few consumers obtained written information during their wait. The waiting area may have latent possibilities to expand the information function of the pharmacy and combine this with other activities that distract the consumer from the wait. Transdisciplinary research, combining knowledge from pharmacy practice research with consumer research, has been a useful approach to add information on queueing behaviour of consumers.

  15. Vehicle routing problem with time windows using natural inspired algorithms

    Science.gov (United States)

    Pratiwi, A. B.; Pratama, A.; Sa’diyah, I.; Suprajitno, H.

    2018-03-01

    Process of distribution of goods needs a strategy to make the total cost spent for operational activities minimized. But there are several constrains have to be satisfied which are the capacity of the vehicles and the service time of the customers. This Vehicle Routing Problem with Time Windows (VRPTW) gives complex constrains problem. This paper proposes natural inspired algorithms for dealing with constrains of VRPTW which involves Bat Algorithm and Cat Swarm Optimization. Bat Algorithm is being hybrid with Simulated Annealing, the worst solution of Bat Algorithm is replaced by the solution from Simulated Annealing. Algorithm which is based on behavior of cats, Cat Swarm Optimization, is improved using Crow Search Algorithm to make simplier and faster convergence. From the computational result, these algorithms give good performances in finding the minimized total distance. Higher number of population causes better computational performance. The improved Cat Swarm Optimization with Crow Search gives better performance than the hybridization of Bat Algorithm and Simulated Annealing in dealing with big data.

  16. Cosmic radiation algorithm utilizing flight time tables

    International Nuclear Information System (INIS)

    Katja Kojo, M.Sc.; Mika Helminen, M.Sc.; Anssi Auvinen, M.D.Ph.D.; Katja Kojo, M.Sc.; Anssi Auvinen, M.D.Ph.D.; Gerhard Leuthold, D.Sc.

    2006-01-01

    Cosmic radiation is considerably higher on cruising altitudes used in aviation than at ground level. Exposure to cosmic radiation may increase cancer risk among pilots and cabin crew. The International Commission on Radiation Protection (ICRP) has recommended that air crew should be classified as radiation workers. Quantification of cosmic radiation doses is necessary for assessment of potential health effects of such occupational exposure. For Finnair cabin crew (cabin attendants and stewards), flight history is not available for years prior to 1991 and therefore, other sources of information on number and type of flights have to be used. The lack of systematically recorded information is a problem for dose estimation for many other flight companies personnel as well. Several cosmic radiation dose estimations for cabin crew have been performed using different methods (e.g. 2-5), but they have suffered from various shortcomings. Retrospective exposure estimation is not possible with personal portable dosimeters. Methods that employ survey data for occupational dose assessment are prone to non-differential measurement error i.e. the cabin attendants do not remember correctly the number of past flights. Assessment procedures that utilize surrogate measurement methods i.e. the duration of employment, lack precision. The aim of the present study was to develop an assessment method for individual occupational exposure to cosmic radiation based on flight time tables. Our method provides an assessment method that does not require survey data or systematic recording of flight history, and it is rather quick, inexpensive, and possible to carry out in all other flight companies whose past time tables for the past periods exist. Dose assessment methods that employ survey data are prone to random error i.e. the cabin attendants do not remember correctly the number or types of routes that they have flown during the past. Our method avoids this since survey data are not needed

  17. Time reversibility, computer simulation, algorithms, chaos

    CERN Document Server

    Hoover, William Graham

    2012-01-01

    A small army of physicists, chemists, mathematicians, and engineers has joined forces to attack a classic problem, the "reversibility paradox", with modern tools. This book describes their work from the perspective of computer simulation, emphasizing the author's approach to the problem of understanding the compatibility, and even inevitability, of the irreversible second law of thermodynamics with an underlying time-reversible mechanics. Computer simulation has made it possible to probe reversibility from a variety of directions and "chaos theory" or "nonlinear dynamics" has supplied a useful vocabulary and a set of concepts, which allow a fuller explanation of irreversibility than that available to Boltzmann or to Green, Kubo and Onsager. Clear illustration of concepts is emphasized throughout, and reinforced with a glossary of technical terms from the specialized fields which have been combined here to focus on a common theme. The book begins with a discussion, contrasting the idealized reversibility of ba...

  18. Learning to wait

    DEFF Research Database (Denmark)

    Dungey, Claire Elisabeth; Meinert, Lotte

    2017-01-01

    enforced through discipline, prepare young people to expect that waiting and enduring hardship will pay off in the end. This expectation makes the status of adulthood particularly vulnerable because the jobs and opportunities that young men learn to wait for often do not come into being by waiting....

  19. A real time sorting algorithm to time sort any deterministic time disordered data stream

    Science.gov (United States)

    Saini, J.; Mandal, S.; Chakrabarti, A.; Chattopadhyay, S.

    2017-12-01

    In new generation high intensity high energy physics experiments, millions of free streaming high rate data sources are to be readout. Free streaming data with associated time-stamp can only be controlled by thresholds as there is no trigger information available for the readout. Therefore, these readouts are prone to collect large amount of noise and unwanted data. For this reason, these experiments can have output data rate of several orders of magnitude higher than the useful signal data rate. It is therefore necessary to perform online processing of the data to extract useful information from the full data set. Without trigger information, pre-processing on the free streaming data can only be done with time based correlation among the data set. Multiple data sources have different path delays and bandwidth utilizations and therefore the unsorted merged data requires significant computational efforts for real time manifestation of sorting before analysis. Present work reports a new high speed scalable data stream sorting algorithm with its architectural design, verified through Field programmable Gate Array (FPGA) based hardware simulation. Realistic time based simulated data likely to be collected in an high energy physics experiment have been used to study the performance of the algorithm. The proposed algorithm uses parallel read-write blocks with added memory management and zero suppression features to make it efficient for high rate data-streams. This algorithm is best suited for online data streams with deterministic time disorder/unsorting on FPGA like hardware.

  20. A distributed scheduling algorithm for heterogeneous real-time systems

    Science.gov (United States)

    Zeineldine, Osman; El-Toweissy, Mohamed; Mukkamala, Ravi

    1991-01-01

    Much of the previous work on load balancing and scheduling in distributed environments was concerned with homogeneous systems and homogeneous loads. Several of the results indicated that random policies are as effective as other more complex load allocation policies. The effects of heterogeneity on scheduling algorithms for hard real time systems is examined. A distributed scheduler specifically to handle heterogeneities in both nodes and node traffic is proposed. The performance of the algorithm is measured in terms of the percentage of jobs discarded. While a random task allocation is very sensitive to heterogeneities, the algorithm is shown to be robust to such non-uniformities in system components and load.

  1. Linear Time Local Approximation Algorithm for Maximum Stable Marriage

    Directory of Open Access Journals (Sweden)

    Zoltán Király

    2013-08-01

    Full Text Available We consider a two-sided market under incomplete preference lists with ties, where the goal is to find a maximum size stable matching. The problem is APX-hard, and a 3/2-approximation was given by McDermid [1]. This algorithm has a non-linear running time, and, more importantly needs global knowledge of all preference lists. We present a very natural, economically reasonable, local, linear time algorithm with the same ratio, using some ideas of Paluch [2]. In this algorithm every person make decisions using only their own list, and some information asked from members of these lists (as in the case of the famous algorithm of Gale and Shapley. Some consequences to the Hospitals/Residents problem are also discussed.

  2. Whittling Down the Wait Time: Exploring Models to Minimize the Delay from Initial Concern to Diagnosis and Treatment of Autism Spectrum Disorder.

    Science.gov (United States)

    Gordon-Lipkin, Eliza; Foster, Jessica; Peacock, Georgina

    2016-10-01

    The process from initial concerns to diagnosis of autism spectrum disorder (ASD) can be a long and complicated process. The traditional model for evaluation and diagnosis of ASD often consists of long wait-lists and evaluations that result in a 2-year difference between the earliest signs of ASD and mean age of diagnosis. Multiple factors contribute to this diagnostic bottleneck, including time-consuming evaluations, cost of care, lack of providers, and lack of comfort of primary care providers to diagnose autism. This article explores innovative clinical models that have been implemented to address this as well as future directions and opportunities. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. ALGORITHMIC CONSTRUCTION SCHEDULES IN CONDITIONS OF TIMING CONSTRAINTS

    Directory of Open Access Journals (Sweden)

    Alexey S. Dobrynin

    2014-01-01

    Full Text Available Tasks of time-schedule construction (JSSP in various fields of human activities have an important theoretical and practical significance. The main feature of these tasks is a timing requirement, describing allowed planning time periods and periods of downtime. This article describes implementation variations of the work scheduling algorithm under timing requirements for the tasks of industrial time-schedules construction, and service activities.

  4. Waiting for surgery from the patient perspective

    Directory of Open Access Journals (Sweden)

    Tracey Carr

    2009-10-01

    Full Text Available Tracey Carr1, Ulrich Teucher2, Jackie Mann4, Alan G Casson31Health Sciences, 2Department of Psychology, 3Department of Surgery, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; 4Acute Care, Saskatoon Health Region, Saskatoon, Saskatchewan, CanadaAbstract: The aim of this study was to perform a systematic review of the impact of waiting for elective surgery from the patient perspective, with a focus on maximum tolerance, quality of life, and the nature of the waiting experience. Searches were conducted using Medline, PubMed, CINAHL, EMBASE, and HealthSTAR. Twenty-seven original research articles were identified which included each of these three themes. The current literature suggested that first, patients tend to state longer wait times as unacceptable when they experienced severe symptoms or functional impairment. Second, the relationship between length of wait and health-related quality of life depended on the nature and severity of proposed surgical intervention at the time of booking. Third, the waiting experience was consistently described as stressful and anxiety provoking. While many patients expressed anger and frustration at communication within the system, the experience of waiting was not uniformly negative. Some patients experienced waiting as an opportunity to live full lives despite pain and disability. The relatively unexamined relationship between waiting, illness and patient experience of time represents an area for future research.Keywords: wait time, scheduled surgery, patient perspective, literature review

  5. Magnetotelluric inversion via reverse time migration algorithm of seismic data

    International Nuclear Information System (INIS)

    Ha, Taeyoung; Shin, Changsoo

    2007-01-01

    We propose a new algorithm for two-dimensional magnetotelluric (MT) inversion. Our algorithm is an MT inversion based on the steepest descent method, borrowed from the backpropagation technique of seismic inversion or reverse time migration, introduced in the middle 1980s by Lailly and Tarantola. The steepest descent direction can be calculated efficiently by using the symmetry of numerical Green's function derived from a mixed finite element method proposed by Nedelec for Maxwell's equation, without calculating the Jacobian matrix explicitly. We construct three different objective functions by taking the logarithm of the complex apparent resistivity as introduced in the recent waveform inversion algorithm by Shin and Min. These objective functions can be naturally separated into amplitude inversion, phase inversion and simultaneous inversion. We demonstrate our algorithm by showing three inversion results for synthetic data

  6. A Harmony Search Algorithm approach for optimizing traffic signal timings

    Directory of Open Access Journals (Sweden)

    Mauro Dell'Orco

    2013-07-01

    Full Text Available In this study, a bi-level formulation is presented for solving the Equilibrium Network Design Problem (ENDP. The optimisation of the signal timing has been carried out at the upper-level using the Harmony Search Algorithm (HSA, whilst the traffic assignment has been carried out through the Path Flow Estimator (PFE at the lower level. The results of HSA have been first compared with those obtained using the Genetic Algorithm, and the Hill Climbing on a two-junction network for a fixed set of link flows. Secondly, the HSA with PFE has been applied to the medium-sized network to show the applicability of the proposed algorithm in solving the ENDP. Additionally, in order to test the sensitivity of perceived travel time error, we have used the HSA with PFE with various level of perceived travel time. The results showed that the proposed method is quite simple and efficient in solving the ENDP.

  7. Computing return times or return periods with rare event algorithms

    Science.gov (United States)

    Lestang, Thibault; Ragone, Francesco; Bréhier, Charles-Edouard; Herbert, Corentin; Bouchet, Freddy

    2018-04-01

    The average time between two occurrences of the same event, referred to as its return time (or return period), is a useful statistical concept for practical applications. For instance insurances or public agencies may be interested by the return time of a 10 m flood of the Seine river in Paris. However, due to their scarcity, reliably estimating return times for rare events is very difficult using either observational data or direct numerical simulations. For rare events, an estimator for return times can be built from the extrema of the observable on trajectory blocks. Here, we show that this estimator can be improved to remain accurate for return times of the order of the block size. More importantly, we show that this approach can be generalised to estimate return times from numerical algorithms specifically designed to sample rare events. So far those algorithms often compute probabilities, rather than return times. The approach we propose provides a computationally extremely efficient way to estimate numerically the return times of rare events for a dynamical system, gaining several orders of magnitude of computational costs. We illustrate the method on two kinds of observables, instantaneous and time-averaged, using two different rare event algorithms, for a simple stochastic process, the Ornstein–Uhlenbeck process. As an example of realistic applications to complex systems, we finally discuss extreme values of the drag on an object in a turbulent flow.

  8. HMC algorithm with multiple time scale integration and mass preconditioning

    Science.gov (United States)

    Urbach, C.; Jansen, K.; Shindler, A.; Wenger, U.

    2006-01-01

    We present a variant of the HMC algorithm with mass preconditioning (Hasenbusch acceleration) and multiple time scale integration. We have tested this variant for standard Wilson fermions at β=5.6 and at pion masses ranging from 380 to 680 MeV. We show that in this situation its performance is comparable to the recently proposed HMC variant with domain decomposition as preconditioner. We give an update of the "Berlin Wall" figure, comparing the performance of our variant of the HMC algorithm to other published performance data. Advantages of the HMC algorithm with mass preconditioning and multiple time scale integration are that it is straightforward to implement and can be used in combination with a wide variety of lattice Dirac operators.

  9. Detecting structural breaks in time series via genetic algorithms

    DEFF Research Database (Denmark)

    Doerr, Benjamin; Fischer, Paul; Hilbert, Astrid

    2016-01-01

    of the time series under consideration is available. Therefore, a black-box optimization approach is our method of choice for detecting structural breaks. We describe a genetic algorithm framework which easily adapts to a large number of statistical settings. To evaluate the usefulness of different crossover...... and mutation operations for this problem, we conduct extensive experiments to determine good choices for the parameters and operators of the genetic algorithm. One surprising observation is that use of uniform and one-point crossover together gave significantly better results than using either crossover...... operator alone. Moreover, we present a specific fitness function which exploits the sparse structure of the break points and which can be evaluated particularly efficiently. The experiments on artificial and real-world time series show that the resulting algorithm detects break points with high precision...

  10. G-quadruplex and G-rich sequence stimulate Pif1p-catalyzed downstream duplex DNA unwinding through reducing waiting time at ss/dsDNA junction

    Science.gov (United States)

    Zhang, Bo; Wu, Wen-Qiang; Liu, Na-Nv; Duan, Xiao-Lei; Li, Ming; Dou, Shuo-Xing; Hou, Xi-Miao; Xi, Xu-Guang

    2016-01-01

    Alternative DNA structures that deviate from B-form double-stranded DNA such as G-quadruplex (G4) DNA can be formed by G-rich sequences that are widely distributed throughout the human genome. We have previously shown that Pif1p not only unfolds G4, but also unwinds the downstream duplex DNA in a G4-stimulated manner. In the present study, we further characterized the G4-stimulated duplex DNA unwinding phenomenon by means of single-molecule fluorescence resonance energy transfer. It was found that Pif1p did not unwind the partial duplex DNA immediately after unfolding the upstream G4 structure, but rather, it would dwell at the ss/dsDNA junction with a ‘waiting time’. Further studies revealed that the waiting time was in fact related to a protein dimerization process that was sensitive to ssDNA sequence and would become rapid if the sequence is G-rich. Furthermore, we identified that the G-rich sequence, as the G4 structure, equally stimulates duplex DNA unwinding. The present work sheds new light on the molecular mechanism by which G4-unwinding helicase Pif1p resolves physiological G4/duplex DNA structures in cells. PMID:27471032

  11. Waiting for a pacemaker

    DEFF Research Database (Denmark)

    Risgaard, Bjarke; Elming, Hanne; Jensen, Gunnar

    2012-01-01

    AIMS: To determine waiting period-related morbidity, mortality, and adverse events in acute patients waiting for a permanent pacemaker (PPM).METHODS AND RESULTS: A retrospective chart review of all PPM implantations in Region Zealand, Denmark, in 2009 was conducted. Patients were excluded...... at least one adverse event during the waiting period. The present study indicates that a waiting period is dangerous as it is associated with an increased risk of adverse events. Acute PPMs should be implanted with a 24-h pacemaker implantation service capacity....

  12. Evolutionary algorithms for the Vehicle Routing Problem with Time Windows

    NARCIS (Netherlands)

    Bräysy, Olli; Dullaert, Wout; Gendreau, Michel

    2004-01-01

    This paper surveys the research on evolutionary algorithms for the Vehicle Routing Problem with Time Windows (VRPTW). The VRPTW can be described as the problem of designing least cost routes from a single depot to a set of geographically scattered points. The routes must be designed in such a way

  13. An Expectation Maximization Algorithm to Model Failure Times by Continuous-Time Markov Chains

    Directory of Open Access Journals (Sweden)

    Qihong Duan

    2010-01-01

    Full Text Available In many applications, the failure rate function may present a bathtub shape curve. In this paper, an expectation maximization algorithm is proposed to construct a suitable continuous-time Markov chain which models the failure time data by the first time reaching the absorbing state. Assume that a system is described by methods of supplementary variables, the device of stage, and so on. Given a data set, the maximum likelihood estimators of the initial distribution and the infinitesimal transition rates of the Markov chain can be obtained by our novel algorithm. Suppose that there are m transient states in the system and that there are n failure time data. The devised algorithm only needs to compute the exponential of m×m upper triangular matrices for O(nm2 times in each iteration. Finally, the algorithm is applied to two real data sets, which indicates the practicality and efficiency of our algorithm.

  14. Real coded genetic algorithm for fuzzy time series prediction

    Science.gov (United States)

    Jain, Shilpa; Bisht, Dinesh C. S.; Singh, Phool; Mathpal, Prakash C.

    2017-10-01

    Genetic Algorithm (GA) forms a subset of evolutionary computing, rapidly growing area of Artificial Intelligence (A.I.). Some variants of GA are binary GA, real GA, messy GA, micro GA, saw tooth GA, differential evolution GA. This research article presents a real coded GA for predicting enrollments of University of Alabama. Data of Alabama University is a fuzzy time series. Here, fuzzy logic is used to predict enrollments of Alabama University and genetic algorithm optimizes fuzzy intervals. Results are compared to other eminent author works and found satisfactory, and states that real coded GA are fast and accurate.

  15. Algorithmic Approach to Abstracting Linear Systems by Timed Automata

    DEFF Research Database (Denmark)

    Sloth, Christoffer; Wisniewski, Rafael

    2011-01-01

    This paper proposes an LMI-based algorithm for abstracting dynamical systems by timed automata, which enables automatic formal verification of linear systems. The proposed abstraction is based on partitioning the state space of the system using positive invariant sets, generated by Lyapunov...... functions. This partitioning ensures that the vector field of the dynamical system is transversal to all facets of the cells, which induces some desirable properties of the abstraction. The algorithm is based on identifying intersections of level sets of quadratic Lyapunov functions, and determining...

  16. Reducing the time requirement of k-means algorithm.

    Science.gov (United States)

    Osamor, Victor Chukwudi; Adebiyi, Ezekiel Femi; Oyelade, Jelilli Olarenwaju; Doumbia, Seydou

    2012-01-01

    Traditional k-means and most k-means variants are still computationally expensive for large datasets, such as microarray data, which have large datasets with large dimension size d. In k-means clustering, we are given a set of n data points in d-dimensional space R(d) and an integer k. The problem is to determine a set of k points in R(d), called centers, so as to minimize the mean squared distance from each data point to its nearest center. In this work, we develop a novel k-means algorithm, which is simple but more efficient than the traditional k-means and the recent enhanced k-means. Our new algorithm is based on the recently established relationship between principal component analysis and the k-means clustering. We provided the correctness proof for this algorithm. Results obtained from testing the algorithm on three biological data and six non-biological data (three of these data are real, while the other three are simulated) also indicate that our algorithm is empirically faster than other known k-means algorithms. We assessed the quality of our algorithm clusters against the clusters of a known structure using the Hubert-Arabie Adjusted Rand index (ARI(HA)). We found that when k is close to d, the quality is good (ARI(HA)>0.8) and when k is not close to d, the quality of our new k-means algorithm is excellent (ARI(HA)>0.9). In this paper, emphases are on the reduction of the time requirement of the k-means algorithm and its application to microarray data due to the desire to create a tool for clustering and malaria research. However, the new clustering algorithm can be used for other clustering needs as long as an appropriate measure of distance between the centroids and the members is used. This has been demonstrated in this work on six non-biological data.

  17. Time-advance algorithms based on Hamilton's principle

    International Nuclear Information System (INIS)

    Lewis, H.R.; Kostelec, P.J.

    1993-01-01

    Time-advance algorithms based on Hamilton's variational principle are being developed for application to problems in plasma physics and other areas. Hamilton's principle was applied previously to derive a system of ordinary differential equations in time whose solution provides an approximation to the evolution of a plasma described by the Vlasov-Maxwell equations. However, the variational principle was not used to obtain an algorithm for solving the ordinary differential equations numerically. The present research addresses the numerical solution of systems of ordinary differential equations via Hamilton's principle. The basic idea is first to choose a class of functions for approximating the solution of the ordinary differential equations over a specific time interval. Then the parameters in the approximating function are determined by applying Hamilton's principle exactly within the class of approximating functions. For example, if an approximate solution is desired between time t and time t + Δ t, the class of approximating functions could be polynomials in time up to some degree. The issue of how to choose time-advance algorithms is very important for achieving efficient, physically meaningful computer simulations. The objective is to reliably simulate those characteristics of an evolving system that are scientifically most relevant. Preliminary numerical results are presented, including comparisons with other computational methods

  18. Feature Selection Criteria for Real Time EKF-SLAM Algorithm

    Directory of Open Access Journals (Sweden)

    Fernando Auat Cheein

    2010-02-01

    Full Text Available This paper presents a seletion procedure for environmet features for the correction stage of a SLAM (Simultaneous Localization and Mapping algorithm based on an Extended Kalman Filter (EKF. This approach decreases the computational time of the correction stage which allows for real and constant-time implementations of the SLAM. The selection procedure consists in chosing the features the SLAM system state covariance is more sensible to. The entire system is implemented on a mobile robot equipped with a range sensor laser. The features extracted from the environment correspond to lines and corners. Experimental results of the real time SLAM algorithm and an analysis of the processing-time consumed by the SLAM with the feature selection procedure proposed are shown. A comparison between the feature selection approach proposed and the classical sequential EKF-SLAM along with an entropy feature selection approach is also performed.

  19. Distributed Scheduling in Time Dependent Environments: Algorithms and Analysis

    OpenAIRE

    Shmuel, Ori; Cohen, Asaf; Gurewitz, Omer

    2017-01-01

    Consider the problem of a multiple access channel in a time dependent environment with a large number of users. In such a system, mostly due to practical constraints (e.g., decoding complexity), not all users can be scheduled together, and usually only one user may transmit at any given time. Assuming a distributed, opportunistic scheduling algorithm, we analyse the system's properties, such as delay, QoS and capacity scaling laws. Specifically, we start with analyzing the performance while \\...

  20. Waiting Online: A Review and Research Agenda.

    Science.gov (United States)

    Ryan, Gerard; Valverde, Mireia

    2003-01-01

    Reviews 21 papers based on 13 separate empirical studies on waiting on the Internet, drawn from the areas of marketing, system response time, and quality of service studies. The article proposes an agenda for future research, including extending the range of research methodologies, broadening the definition of waiting on the Internet, and…

  1. Transformation Algorithm of Dielectric Response in Time-Frequency Domain

    Directory of Open Access Journals (Sweden)

    Ji Liu

    2014-01-01

    Full Text Available A transformation algorithm of dielectric response from time domain to frequency domain is presented. In order to shorten measuring time of low or ultralow frequency dielectric response characteristics, the transformation algorithm is used in this paper to transform the time domain relaxation current to frequency domain current for calculating the low frequency dielectric dissipation factor. In addition, it is shown from comparing the calculation results with actual test data that there is a coincidence for both results over a wide range of low frequencies. Meanwhile, the time domain test data of depolarization currents in dry and moist pressboards are converted into frequency domain results on the basis of the transformation. The frequency domain curves of complex capacitance and dielectric dissipation factor at the low frequency range are obtained. Test results of polarization and depolarization current (PDC in pressboards are also given at the different voltage and polarization time. It is demonstrated from the experimental results that polarization and depolarization current are affected significantly by moisture contents of the test pressboards, and the transformation algorithm is effective in ultralow frequency of 10−3 Hz. Data analysis and interpretation of the test results conclude that analysis of time-frequency domain dielectric response can be used for assessing insulation system in power transformer.

  2. The control of deliberate waiting strategies in a stop-signal task

    Directory of Open Access Journals (Sweden)

    R.P. Sylwan

    2004-06-01

    Full Text Available To inhibit an ongoing flow of thoughts or actions has been largely considered to be a crucial executive function, and the stop-signal paradigm makes inhibitory control measurable. Stop-signal tasks usually combine two concurrent tasks, i.e., manual responses to a primary task (go-task are occasionally countermanded by a stimulus which signals participants to inhibit their response in that trial (stop-task. Participants are always instructed not to wait for the stop-signal, since waiting strategies cause the response times to be unstable, invalidating the data. The aim of the present study was to experimentally control the strategies of waiting deliberately for the stop-signal in a stop-task by means of an algorithm that measured the variation in the reaction times to go-stimuli on-line, and displayed a warning legend urging participants to be faster when their reaction times were more than two standard deviations of the mean. Thirty-four university students performed a stop-task with go- and stop-stimuli, both of which were delivered in the visual modality and were lateralized within the visual field. The participants were divided into two groups (group A, without the algorithm, vs group B, with the algorithm. Group B exhibited lower variability of reaction times to go-stimuli, whereas no significant between-group differences were found in any of the measures of inhibitory control, showing that the algorithm succeeded in controlling the deliberate waiting strategies. Differences between deliberate and unintentional waiting strategies, and anxiety as a probable factor responsible for individual differences in deliberate waiting behavior, are discussed.

  3. A decentralized scheduling algorithm for time synchronized channel hopping

    Directory of Open Access Journals (Sweden)

    Andrew Tinka

    2011-09-01

    Full Text Available Time Synchronized Channel Hopping (TSCH is an existing Medium Access Control scheme which enables robust communication through channel hopping and high data rates through synchronization. It is based on a time-slotted architecture, and its correct functioning depends on a schedule which is typically computed by a central node. This paper presents, to our knowledge, the first scheduling algorithm for TSCH networks which both is distributed and which copes with mobile nodes. Two variations on scheduling algorithms are presented. Aloha-based scheduling allocates one channel for broadcasting advertisements for new neighbors. Reservation- based scheduling augments Aloha-based scheduling with a dedicated timeslot for targeted advertisements based on gossip information. A mobile ad hoc motorized sensor network with frequent connectivity changes is studied, and the performance of the two proposed algorithms is assessed. This performance analysis uses both simulation results and the results of a field deployment of floating wireless sensors in an estuarial canal environment. Reservation-based scheduling performs significantly better than Aloha-based scheduling, suggesting that the improved network reactivity is worth the increased algorithmic complexity and resource consumption.

  4. Efficient Algorithms for Segmentation of Item-Set Time Series

    Science.gov (United States)

    Chundi, Parvathi; Rosenkrantz, Daniel J.

    We propose a special type of time series, which we call an item-set time series, to facilitate the temporal analysis of software version histories, email logs, stock market data, etc. In an item-set time series, each observed data value is a set of discrete items. We formalize the concept of an item-set time series and present efficient algorithms for segmenting a given item-set time series. Segmentation of a time series partitions the time series into a sequence of segments where each segment is constructed by combining consecutive time points of the time series. Each segment is associated with an item set that is computed from the item sets of the time points in that segment, using a function which we call a measure function. We then define a concept called the segment difference, which measures the difference between the item set of a segment and the item sets of the time points in that segment. The segment difference values are required to construct an optimal segmentation of the time series. We describe novel and efficient algorithms to compute segment difference values for each of the measure functions described in the paper. We outline a dynamic programming based scheme to construct an optimal segmentation of the given item-set time series. We use the item-set time series segmentation techniques to analyze the temporal content of three different data sets—Enron email, stock market data, and a synthetic data set. The experimental results show that an optimal segmentation of item-set time series data captures much more temporal content than a segmentation constructed based on the number of time points in each segment, without examining the item set data at the time points, and can be used to analyze different types of temporal data.

  5. Efficient quantum algorithm for computing n-time correlation functions.

    Science.gov (United States)

    Pedernales, J S; Di Candia, R; Egusquiza, I L; Casanova, J; Solano, E

    2014-07-11

    We propose a method for computing n-time correlation functions of arbitrary spinorial, fermionic, and bosonic operators, consisting of an efficient quantum algorithm that encodes these correlations in an initially added ancillary qubit for probe and control tasks. For spinorial and fermionic systems, the reconstruction of arbitrary n-time correlation functions requires the measurement of two ancilla observables, while for bosonic variables time derivatives of the same observables are needed. Finally, we provide examples applicable to different quantum platforms in the frame of the linear response theory.

  6. A Placement Algorithm for Capital Items that Depreciate with Time

    International Nuclear Information System (INIS)

    Wweru, R.M

    1999-01-01

    The replacement algorithm is centred on the prediction of the replacement cost and the determination of the most economical replacement policy. For items whose efficiency depreciates over their life spans e.g. machine tools, vehicles et.c; the prediction of costs involves those factors which contribute to increase operating cost, forced idle time, increase scrap, increased repair cost etc. The alternative to increased cost of operating an aging equipment is the cost of replacing the old equipment with a new one. There is some age at which the replacement of the old equipment is more economical than continuation (of the old one) at the increased operating cost (Johnson R D, Siskin B R, 1989). This algorithm uses certain cost relationships that are vital in minimization of total costs and is focused on capital equipment that depreciates with time as opposed to items with a probabilistic life span

  7. Measuring border delay and crossing times at the US-Mexico border : part II. Guidebook for analysis and dissemination of border crossing time and wait time data.

    Science.gov (United States)

    2012-06-01

    The purpose of this guidebook is to describe to local, regional, and State agencies how to analyze and disseminate data collected by a radio frequency identification (RFID)-based system to measure travel times of commercial vehicles, which is referre...

  8. A RECURSIVE ALGORITHM SUITABLE FOR REAL-TIME MEASUREMENT

    Directory of Open Access Journals (Sweden)

    Giovanni Bucci

    1995-12-01

    Full Text Available This paper deals with a recursive algorithm suitable for realtime measurement applications, based on an indirect technique, useful in those applications where the required quantities cannot be measured in a straightforward way. To cope with time constraints a parallel formulation of it, suitable to be implemented on multiprocessor systems, is presented. The adopted concurrent implementation is based on factorization techniques. Some experimental results related to the application of the system for carrying out measurements on synchronous motors are included.

  9. FPGA implementation of image dehazing algorithm for real time applications

    Science.gov (United States)

    Kumar, Rahul; Kaushik, Brajesh Kumar; Balasubramanian, R.

    2017-09-01

    Weather degradation such as haze, fog, mist, etc. severely reduces the effective range of visual surveillance. This degradation is a spatially varying phenomena, which makes this problem non trivial. Dehazing is an essential preprocessing stage in applications such as long range imaging, border security, intelligent transportation system, etc. However, these applications require low latency of the preprocessing block. In this work, single image dark channel prior algorithm is modified and implemented for fast processing with comparable visual quality of the restored image/video. Although conventional single image dark channel prior algorithm is computationally expensive, it yields impressive results. Moreover, a two stage image dehazing architecture is introduced, wherein, dark channel and airlight are estimated in the first stage. Whereas, transmission map and intensity restoration are computed in the next stages. The algorithm is implemented using Xilinx Vivado software and validated by using Xilinx zc702 development board, which contains an Artix7 equivalent Field Programmable Gate Array (FPGA) and ARM Cortex A9 dual core processor. Additionally, high definition multimedia interface (HDMI) has been incorporated for video feed and display purposes. The results show that the dehazing algorithm attains 29 frames per second for the image resolution of 1920x1080 which is suitable of real time applications. The design utilizes 9 18K_BRAM, 97 DSP_48, 6508 FFs and 8159 LUTs.

  10. Continuous-time quantum algorithms for unstructured problems

    International Nuclear Information System (INIS)

    Hen, Itay

    2014-01-01

    We consider a family of unstructured optimization problems, for which we propose a method for constructing analogue, continuous-time (not necessarily adiabatic) quantum algorithms that are faster than their classical counterparts. In this family of problems, which we refer to as ‘scrambled input’ problems, one has to find a minimum-cost configuration of a given integer-valued n-bit black-box function whose input values have been scrambled in some unknown way. Special cases within this set of problems are Grover’s search problem of finding a marked item in an unstructured database, certain random energy models, and the functions of the Deutsch–Josza problem. We consider a couple of examples in detail. In the first, we provide an O(1) deterministic analogue quantum algorithm to solve the seminal problem of Deutsch and Josza, in which one has to determine whether an n-bit boolean function is constant (gives 0 on all inputs or 1 on all inputs) or balanced (returns 0 on half the input states and 1 on the other half). We also study one variant of the random energy model, and show that, as one might expect, its minimum energy configuration can be found quadratically faster with a quantum adiabatic algorithm than with classical algorithms. (paper)

  11. Parallel pipeline algorithm of real time star map preprocessing

    Science.gov (United States)

    Wang, Hai-yong; Qin, Tian-mu; Liu, Jia-qi; Li, Zhi-feng; Li, Jian-hua

    2016-03-01

    To improve the preprocessing speed of star map and reduce the resource consumption of embedded system of star tracker, a parallel pipeline real-time preprocessing algorithm is presented. The two characteristics, the mean and the noise standard deviation of the background gray of a star map, are firstly obtained dynamically by the means that the intervene of the star image itself to the background is removed in advance. The criterion on whether or not the following noise filtering is needed is established, then the extraction threshold value is assigned according to the level of background noise, so that the centroiding accuracy is guaranteed. In the processing algorithm, as low as two lines of pixel data are buffered, and only 100 shift registers are used to record the connected domain label, by which the problems of resources wasting and connected domain overflow are solved. The simulating results show that the necessary data of the selected bright stars could be immediately accessed in a delay time as short as 10us after the pipeline processing of a 496×496 star map in 50Mb/s is finished, and the needed memory and registers resource total less than 80kb. To verify the accuracy performance of the algorithm proposed, different levels of background noise are added to the processed ideal star map, and the statistic centroiding error is smaller than 1/23 pixel under the condition that the signal to noise ratio is greater than 1. The parallel pipeline algorithm of real time star map preprocessing helps to increase the data output speed and the anti-dynamic performance of star tracker.

  12. Commercial border crossing and wait time measurement at Laredo World Trade Bridge and the Colombia-Solidarity Bridge.

    Science.gov (United States)

    2012-03-01

    This research is to establish a baseline and on-going measurement of border crossing times and : delay by measuring travel times for commercial trucks crossing the port of entry (POE) from : Mexico into Texas at the Laredo World Trade Bridge and the ...

  13. Implementing wait-time reductions under Ontario government benchmarks (Pay-for-Results): a Cluster Randomized Trial of the Effect of a Physician-Nurse Supplementary Triage Assistance team (MDRNSTAT) on emergency department patient wait times.

    Science.gov (United States)

    Cheng, Ivy; Lee, Jacques; Mittmann, Nicole; Tyberg, Jeffrey; Ramagnano, Sharon; Kiss, Alex; Schull, Michael; Kerr, Fergus; Zwarenstein, Merrick

    2013-11-11

    Internationally, emergency departments are struggling with crowding and its associated morbidity, mortality, and decreased patient and health-care worker satisfaction. The objective was to evaluate the addition of a MDRNSTAT (Physician (MD)-Nurse (RN) Supplementary Team At Triage) on emergency department patient flow and quality of care. Pragmatic cluster randomized trial. From 131 weekday shifts (8:00-14:30) during a 26-week period, we randomized 65 days (3173 visits) to the intervention cluster with a MDRNSTAT presence, and 66 days (3163 visits) to the nurse-only triage control cluster. The primary outcome was emergency department length-of-stay (EDLOS) for patients managed and discharged only by the emergency department. Secondary outcomes included EDLOS for patients initially seen by the emergency department, and subsequently consulted and admitted, patients reaching government-mandated thresholds, time to initial physician assessment, left-without being seen rate, time to investigation, and measurement of harm. The intervention's median EDLOS for discharged, non-consulted, high acuity patients was 4:05 [95th% CI: 3:58 to 4:15] versus 4:29 [95th% CI: 4:19-4:38] during comparator shifts. The intervention's median EDLOS for discharged, non-consulted, low acuity patients was 1:55 [95th% CI: 1:48 to 2:05] versus 2:08 [95th% CI: 2:02-2:14]. The intervention's median physician initial assessment time was 0:55 [95th% CI: 0:53 to 0:58] versus 1:21 [95th% CI: 1:18 to 1:25]. The intervention's left-without-being-seen rate was 1.5% versus 2.2% for the control (p = 0.06). The MDRNSTAT subgroup analysis resulted in significant decreases in median EDLOS for discharged, non-consulted high (4:01 [95th% CI: 3:43-4:16]) and low acuity patients (1:10 95th% CI: 0:58-1:19]), as well as physician initial assessment time (0:25 [95th% CI: 0:23-0:26]). No patients returned to the emergency department after being discharged by the MDRNSTAT at triage. The intervention reduced delays

  14. Time Optimized Algorithm for Web Document Presentation Adaptation

    DEFF Research Database (Denmark)

    Pan, Rong; Dolog, Peter

    2010-01-01

    Currently information on the web is accessed through different devices. Each device has its own properties such as resolution, size, and capabilities to display information in different format and so on. This calls for adaptation of information presentation for such platforms. This paper proposes...... content-optimized and time-optimized algorithms for information presentation adaptation for different devices based on its hierarchical model. The model is formalized in order to experiment with different algorithms.......Currently information on the web is accessed through different devices. Each device has its own properties such as resolution, size, and capabilities to display information in different format and so on. This calls for adaptation of information presentation for such platforms. This paper proposes...

  15. Identifying Time Measurement Tampering in the Traversal Time and Hop Count Analysis (TTHCA Wormhole Detection Algorithm

    Directory of Open Access Journals (Sweden)

    Jonny Karlsson

    2013-05-01

    Full Text Available Traversal time and hop count analysis (TTHCA is a recent wormhole detection algorithm for mobile ad hoc networks (MANET which provides enhanced detection performance against all wormhole attack variants and network types. TTHCA involves each node measuring the processing time of routing packets during the route discovery process and then delivering the measurements to the source node. In a participation mode (PM wormhole where malicious nodes appear in the routing tables as legitimate nodes, the time measurements can potentially be altered so preventing TTHCA from successfully detecting the wormhole. This paper analyses the prevailing conditions for time tampering attacks to succeed for PM wormholes, before introducing an extension to the TTHCA detection algorithm called ∆T Vector which is designed to identify time tampering, while preserving low false positive rates. Simulation results confirm that the ∆T Vector extension is able to effectively detect time tampering attacks, thereby providing an important security enhancement to the TTHCA algorithm.

  16. The impact of nurse practitioner services on cost, quality of care, satisfaction and waiting times in the emergency department: a systematic review.

    Science.gov (United States)

    Jennings, Natasha; Clifford, Stuart; Fox, Amanda R; O'Connell, Jane; Gardner, Glenn

    2015-01-01

    To provide the best available evidence to determine the impact of nurse practitioner services on cost, quality of care, satisfaction and waiting times in the emergency department for adult patients. The delivery of quality care in the emergency department is emerging as one of the most important service indicators in health delivery. Increasing service pressures in the emergency department have resulted in the adoption of service innovation models: the most common and rapidly expanding of these is emergency nurse practitioner services. The rapid uptake of emergency nurse practitioner service in Australia has outpaced the capacity to evaluate this service model in terms of outcomes related to safety and quality of patient care. Previous research is now outdated and not commensurate with the changing domain of delivering emergency care with nurse practitioner services. A comprehensive search of four electronic databases from 2006 to 2013 was conducted to identify research evaluating nurse practitioner service impact in the emergency department. English language articles were sought using MEDLINE, CINAHL, Embase and Cochrane and included two previous systematic reviews completed five and seven years ago. A three step approach was used. Following a comprehensive search, two reviewers assessed all identified studies against the inclusion criteria. From the original 1013 studies, 14 papers were retained for critical appraisal on methodological quality by two independent reviewers and data were extracted using standardised tools. Narrative synthesis was conducted to summarise and report the findings as insufficient data was available for meta-analysis of results. This systematic review has shown that emergency nurse practitioner service has a positive impact on quality of care, patient satisfaction and waiting times. There was insufficient evidence to draw conclusions regarding outcomes of a cost benefit analysis. Synthesis of the available research attempts to provide an

  17. Real time tracking by LOPF algorithm with mixture model

    Science.gov (United States)

    Meng, Bo; Zhu, Ming; Han, Guangliang; Wu, Zhiguo

    2007-11-01

    A new particle filter-the Local Optimum Particle Filter (LOPF) algorithm is presented for tracking object accurately and steadily in visual sequences in real time which is a challenge task in computer vision field. In order to using the particles efficiently, we first use Sobel algorithm to extract the profile of the object. Then, we employ a new Local Optimum algorithm to auto-initialize some certain number of particles from these edge points as centre of the particles. The main advantage we do this in stead of selecting particles randomly in conventional particle filter is that we can pay more attentions on these more important optimum candidates and reduce the unnecessary calculation on those negligible ones, in addition we can overcome the conventional degeneracy phenomenon in a way and decrease the computational costs. Otherwise, the threshold is a key factor that affecting the results very much. So here we adapt an adaptive threshold choosing method to get the optimal Sobel result. The dissimilarities between the target model and the target candidates are expressed by a metric derived from the Bhattacharyya coefficient. Here, we use both the counter cue to select the particles and the color cur to describe the targets as the mixture target model. The effectiveness of our scheme is demonstrated by real visual tracking experiments. Results from simulations and experiments with real video data show the improved performance of the proposed algorithm when compared with that of the standard particle filter. The superior performance is evident when the target encountering the occlusion in real video where the standard particle filter usually fails.

  18. A class of kernel based real-time elastography algorithms.

    Science.gov (United States)

    Kibria, Md Golam; Hasan, Md Kamrul

    2015-08-01

    In this paper, a novel real-time kernel-based and gradient-based Phase Root Seeking (PRS) algorithm for ultrasound elastography is proposed. The signal-to-noise ratio of the strain image resulting from this method is improved by minimizing the cross-correlation discrepancy between the pre- and post-compression radio frequency signals with an adaptive temporal stretching method and employing built-in smoothing through an exponentially weighted neighborhood kernel in the displacement calculation. Unlike conventional PRS algorithms, displacement due to tissue compression is estimated from the root of the weighted average of the zero-lag cross-correlation phases of the pair of corresponding analytic pre- and post-compression windows in the neighborhood kernel. In addition to the proposed one, the other time- and frequency-domain elastography algorithms (Ara et al., 2013; Hussain et al., 2012; Hasan et al., 2012) proposed by our group are also implemented in real-time using Java where the computations are serially executed or parallely executed in multiple processors with efficient memory management. Simulation results using finite element modeling simulation phantom show that the proposed method significantly improves the strain image quality in terms of elastographic signal-to-noise ratio (SNRe), elastographic contrast-to-noise ratio (CNRe) and mean structural similarity (MSSIM) for strains as high as 4% as compared to other reported techniques in the literature. Strain images obtained for the experimental phantom as well as in vivo breast data of malignant or benign masses also show the efficacy of our proposed method over the other reported techniques in the literature. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Costly waiting for the future gas energy

    International Nuclear Information System (INIS)

    1999-01-01

    The article discusses solutions while waiting for the pollution free gas power plant and points out that Norway will have to import Danish power from coal and Swedish nuclear energy for a long time yet. Various future scenarios are mentioned

  20. Waiting times for the appearance of cytotoxic T-lymphocyte escape mutants in chronic HIV-1 infection

    International Nuclear Information System (INIS)

    Liu Yi; Mullins, James I.; Mittler, John E.

    2006-01-01

    The failure of HIV-1 to escape at some cytotoxic T-lymphocyte (CTL) epitopes has generally been explained in terms of viral fitness costs or ineffective or attenuated CTL responses. Relatively little attention has been paid to the evolutionary time required for escape mutants to be detected. This time is significantly affected by selection, mutation rates, the presence of other advantageous mutations, and the effective population size of HIV-1 in vivo (typically estimated to be ∼10 3 in chronically infected patients, though one study has estimated it to be ∼10 5 ). Here, we use a forward simulator with experimentally estimated HIV-1 parameters to show that these delays can be substantial. For an effective population size of 10 3 , even highly advantageous mutants (s = 0.5) may not be detected for a couple of years in chronically infected patients, while moderately advantageous escape mutants (s = 0.1) may not be detected for up to 10 years. Even with an effective population size of 10 5 , a moderately advantageous escape mutant (s = 0.1) may not be detected in the population within 2 years if it has to compete with other selectively advantageous mutants. Stochastic evolutionary forces, therefore, in addition to viral fitness costs and ineffective or attenuated CTL responses, must be taken into account when assessing the selection of CTL escape mutations

  1. Has the time to come leave the "watch-and-wait" strategy in newly diagnosed asymptomatic follicular lymphoma patients?

    Science.gov (United States)

    Rueda, Antonio; Casanova, María; Redondo, Maximino; Pérez-Ruiz, Elisabeth; Medina-Pérez, Angeles

    2012-05-31

    Historically, the median overall survival for follicular lymphoma (FL) has been considered to be 9-10 years, and no treatment had ever prolonged this time period. Studies conducted more than 20 years ago demonstrated that treating patients with asymptomatic FL at the onset of the disease did not increase their survival, and that almost 20% of these patients did not need any treatment in the first 10 years of follow-up. Based on these facts, most clinical practice guidelines recommend active surveillance policies for patients with asymptomatic FL. The introduction of antiCD-20 monoclonal antibodies, over the last 15 years, has significantly increased the median survival rate to above 14 years. This improvement was achieved before the combination of rituximab and chemotherapy regimens became extensively used in patients with symptomatic disease. Therefore, this increase in survival may currently be more significant. At present, several clinical trials have evaluated low-toxicity therapies that prolong progression-free periods, among which rituximab monotherapy, radioimmunotherapy or the combination of rituximab with bendamustine are the most relevant. Unfortunately, these clinical trials have included only patients with symptomatic FL. The results of a recently reported clinical trial show that treatment with single-agent rituximab prolongs progression-free survival rates, time to new treatment and the quality of life of asymptomatic patients, as compared with the active surveillance strategy. Longer follow-up of these results and data regarding overall survival are awaited before this treatment can be recommended as the standard initial therapy. There are different therapeutic possibilities for asymptomatic FL patients, but no data are currently available to indicate which option is the best. Patients need to understand the risks and benefits of observation versus treatment before a final decision can be made. For patients who want active treatment the

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

    Science.gov (United States)

    Kennedy, A.

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

  3. The study of waiting time to first pregnancy in the south of Iran: A parametric frailty model approach

    Directory of Open Access Journals (Sweden)

    Najaf Zare

    2017-08-01

    Full Text Available Background: Time to first pregnancy (TTFP has never been studied in an Iranian setting. Lifestyle, occupational and environmental factors have been suggested to affect the female reproduction. Objective: This study was conducted to measure TTFP in the south of Iran and survey the effects of several similar factors on TTFP by frailty models. Materials and Methods: The data on TTFP were available for 882 women who were randomly selected from the rural population (the south of Iran. Only the first and the planned pregnancies of every woman were included. The data were collected retrospectively by using self-administered questionnaires. Frailty and shared frailty models were used to determine which factors had the highest impact on TTFP. Results: The median TTFP was 6.4 months and several factors were surveyed. However, only the age of marriage, height, maternal education and regularity of menstruation prior to conception were selected in the multivariable models. Conclusion: Among the several factors which were included in the study, the result of frailty model showed that the height, age of marriage and regular menstruation seemed more notable predictors of TTFP.

  4. The Effect of 5S-Continuous Quality Improvement-Total Quality Management Approach on Staff Motivation, Patients' Waiting Time and Patient Satisfaction with Services at Hospitals in Uganda.

    Science.gov (United States)

    Take, Naoki; Byakika, Sarah; Tasei, Hiroshi; Yoshikawa, Toru

    2015-03-31

    This study aimed at analyzing the effect of 5S practice on staff motivation, patients' waiting time and patient satisfaction with health services at hospitals in Uganda. Double-difference estimates were measured for 13 Regional Referral Hospitals and eight General Hospitals implementing 5S practice separately. The study for Regional Referral Hospitals revealed 5S practice had the effect on staff motivation in terms of commitment to work in the current hospital and waiting time in the dispensary in 10 hospitals implementing 5S, but significant difference was not identified on patient satisfaction. The study for General Hospitals indicated the effect of 5S practice on patient satisfaction as well as waiting time, but staff motivation in two hospitals did not improve. 5S practice enables the hospitals to improve the quality of services in terms of staff motivation, waiting time and patient satisfaction and it takes as least four years in Uganda. The fourth year since the commencement of 5S can be a threshold to move forward to the next step, Continuous Quality Improvement.

  5. A MODIFIED GIFFLER AND THOMPSON ALGORITHM COMBINED WITH DYNAMIC SLACK TIME FOR SOLVING DYNAMIC SCHEDULE PROBLEMS

    Directory of Open Access Journals (Sweden)

    Tanti Octavia

    2003-01-01

    Full Text Available A Modified Giffler and Thompson algorithm combined with dynamic slack time is used to allocate machines resources in dynamic nature. It was compared with a Real Time Order Promising (RTP algorithm. The performance of modified Giffler and Thompson and RTP algorithms are measured by mean tardiness. The result shows that modified Giffler and Thompson algorithm combined with dynamic slack time provides significantly better result compared with RTP algorithm in terms of mean tardiness.

  6. Who breaches the four-hour emergency department wait time target? A retrospective analysis of 374,000 emergency department attendances between 2008 and 2013 at a type 1 emergency department in England.

    Science.gov (United States)

    Bobrovitz, Niklas; Lasserson, Daniel S; Briggs, Adam D M

    2017-11-02

    The four-hour target is a key hospital emergency department performance indicator in England and one that drives the physical and organisational design of the ED. Some studies have identified time of presentation as a key factor affecting waiting times. Few studies have investigated other determinants of breaching the four-hour target. Therefore, our objective was to describe patterns of emergency department breaches of the four-hour wait time target and identify patients at highest risk of breaching. This was a retrospective cohort study of a large type 1 Emergency department at an NHS teaching hospital in Oxford, England. We analysed anonymised individual level patient data for 378,873 emergency department attendances, representing all attendances between April 2008 and April 2013. We examined patient characteristics and emergency department presentation circumstances associated with the highest likelihood of breaching the four-hour wait time target. We used 374,459 complete cases for analysis. In total, 8.3% of all patients breached the four-hour wait time target. The main determinants of patients breaching the four-hour wait time target were hour of arrival to the ED, day of the week, patient age, ED referral source, and the types of investigations patients receive (p target were older, presented at night, presented on Monday, received multiple types of investigation in the emergency department, and were not self-referred (p target including patient age, ED referral source, the types of investigations patients receive, as well as the hour, day, and month of arrival to the ED. Efforts to reduce the number of breaches could explore late-evening/overnight staffing, access to diagnostic tests, rapid discharge facilities, and early assessment and input on diagnostic and management strategies from a senior practitioner.

  7. Algorithms

    Indian Academy of Sciences (India)

    polynomial) division have been found in Vedic Mathematics which are dated much before Euclid's algorithm. A programming language Is used to describe an algorithm for execution on a computer. An algorithm expressed using a programming.

  8. Evaluation of patients' attitudes to their care during oral and maxillofacial surgical outpatient consultations: the importance of waiting times and quality of interaction between patient and doctor.

    Science.gov (United States)

    Dimovska, E O F; Sharma, S; Trebble, T M

    2016-06-01

    Knowing what patients think about their care is fundamental to the provision of an effective, quality service, and it can help to direct change and reduce costs. Much of the work in oral and maxillofacial departments concerns the treatment of outpatients, but as little is known about what they think about their care, we aimed to find out which aspects were associated with satisfaction. Consecutive patients (n=244) who attended the oral and maxillofacial outpatient department at Southampton University Hospital NHS Foundation Trust over a 7-day period were given a questionnaire to complete before and after their consultation. It included questions with Likert scale responses on environmental, procedural, and interactive aspects of the visit, and a 16-point scale to rank their priorities. A total of 187 patients (77%) completed the questionnaires. No association was found between expected (p=0.93) or actual (p=0.41) waiting times, and 90% of patients were satisfied with their visit. Seeing the doctor, having confidence in the treatment plan, being listened to, and the ability of the doctor to recognise their personal needs, were ranked as important. Environmental and procedural aspects were considered the least important. These findings may be of value in the development of services to improve patient-centred care. Copyright © 2016 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  9. A time domain phase-gradient based ISAR autofocus algorithm

    CSIR Research Space (South Africa)

    Nel, W

    2011-10-01

    Full Text Available . Results on simulated and measured data show that the algorithm performs well. Unlike many other ISAR autofocus techniques, the algorithm does not make use of several computationally intensive iterations between the data and image domains as part...

  10. Organ Type and Waiting Time

    Science.gov (United States)

    ... to know FAQ Living donation What is living donation? Organs Types Being a living donor First steps Being ... There are many financial resources for transplants. Living donation increases the existing organ supply. It’s important to get to know your ...

  11. A Feedback Optimal Control Algorithm with Optimal Measurement Time Points

    Directory of Open Access Journals (Sweden)

    Felix Jost

    2017-02-01

    Full Text Available Nonlinear model predictive control has been established as a powerful methodology to provide feedback for dynamic processes over the last decades. In practice it is usually combined with parameter and state estimation techniques, which allows to cope with uncertainty on many levels. To reduce the uncertainty it has also been suggested to include optimal experimental design into the sequential process of estimation and control calculation. Most of the focus so far was on dual control approaches, i.e., on using the controls to simultaneously excite the system dynamics (learning as well as minimizing a given objective (performing. We propose a new algorithm, which sequentially solves robust optimal control, optimal experimental design, state and parameter estimation problems. Thus, we decouple the control and the experimental design problems. This has the advantages that we can analyze the impact of measurement timing (sampling independently, and is practically relevant for applications with either an ethical limitation on system excitation (e.g., chemotherapy treatment or the need for fast feedback. The algorithm shows promising results with a 36% reduction of parameter uncertainties for the Lotka-Volterra fishing benchmark example.

  12. Chaos Time Series Prediction Based on Membrane Optimization Algorithms

    Directory of Open Access Journals (Sweden)

    Meng Li

    2015-01-01

    Full Text Available This paper puts forward a prediction model based on membrane computing optimization algorithm for chaos time series; the model optimizes simultaneously the parameters of phase space reconstruction (τ,m and least squares support vector machine (LS-SVM (γ,σ by using membrane computing optimization algorithm. It is an important basis for spectrum management to predict accurately the change trend of parameters in the electromagnetic environment, which can help decision makers to adopt an optimal action. Then, the model presented in this paper is used to forecast band occupancy rate of frequency modulation (FM broadcasting band and interphone band. To show the applicability and superiority of the proposed model, this paper will compare the forecast model presented in it with conventional similar models. The experimental results show that whether single-step prediction or multistep prediction, the proposed model performs best based on three error measures, namely, normalized mean square error (NMSE, root mean square error (RMSE, and mean absolute percentage error (MAPE.

  13. Reactions to waiting online by men and women.

    Science.gov (United States)

    Chebat, Jean-Charles; Salem, Narjes Haj; Poirier, Jean-François; Gélinas-Chebat, Claire

    2010-06-01

    The goal of the present study was to identify factors which may affect the difference between the actual time participants expected to wait for downloading a web page and the perceived waiting time, i.e., the online waiting-time gap. The findings from an experiment in which the music tempo (fast vs. slow) and waiting-duration information (presence vs. absence) were manipulated showed that sex moderated the relation between the manipulated variables and waiting-time gap; emotional response was more important between the manipulated variables and waiting-time gap than was cognitive response. The type of emotional response with an effect on waiting-time gap varied by sex: pleasure for women and arousal for men. For women, pleasure was affected by their cognitive response, while cognitive response played no significant role for men. For both sexes, information on waiting duration increased the perceived waiting time. This study leads to reconsidering the role of emotional response and sex in evaluating waiting time.

  14. Overlay improvements using a real time machine learning algorithm

    Science.gov (United States)

    Schmitt-Weaver, Emil; Kubis, Michael; Henke, Wolfgang; Slotboom, Daan; Hoogenboom, Tom; Mulkens, Jan; Coogans, Martyn; ten Berge, Peter; Verkleij, Dick; van de Mast, Frank

    2014-04-01

    While semiconductor manufacturing is moving towards the 14nm node using immersion lithography, the overlay requirements are tightened to below 5nm. Next to improvements in the immersion scanner platform, enhancements in the overlay optimization and process control are needed to enable these low overlay numbers. Whereas conventional overlay control methods address wafer and lot variation autonomously with wafer pre exposure alignment metrology and post exposure overlay metrology, we see a need to reduce these variations by correlating more of the TWINSCAN system's sensor data directly to the post exposure YieldStar metrology in time. In this paper we will present the results of a study on applying a real time control algorithm based on machine learning technology. Machine learning methods use context and TWINSCAN system sensor data paired with post exposure YieldStar metrology to recognize generic behavior and train the control system to anticipate on this generic behavior. Specific for this study, the data concerns immersion scanner context, sensor data and on-wafer measured overlay data. By making the link between the scanner data and the wafer data we are able to establish a real time relationship. The result is an inline controller that accounts for small changes in scanner hardware performance in time while picking up subtle lot to lot and wafer to wafer deviations introduced by wafer processing.

  15. Real-Time Demand Side Management Algorithm Using Stochastic Optimization

    Directory of Open Access Journals (Sweden)

    Moses Amoasi Acquah

    2018-05-01

    Full Text Available A demand side management technique is deployed along with battery energy-storage systems (BESS to lower the electricity cost by mitigating the peak load of a building. Most of the existing methods rely on manual operation of the BESS, or even an elaborate building energy-management system resorting to a deterministic method that is susceptible to unforeseen growth in demand. In this study, we propose a real-time optimal operating strategy for BESS based on density demand forecast and stochastic optimization. This method takes into consideration uncertainties in demand when accounting for an optimal BESS schedule, making it robust compared to the deterministic case. The proposed method is verified and tested against existing algorithms. Data obtained from a real site in South Korea is used for verification and testing. The results show that the proposed method is effective, even for the cases where the forecasted demand deviates from the observed demand.

  16. Waiting in the surgery.

    Science.gov (United States)

    Fry, F

    1994-07-01

    The concise Oxford English Dictionary defines 'dilemma' as an argument forcing one to choose one of two alternatives, both of which are unfavourable. This is a situation that frequently confronts the general practitioner. This paper will present one practitioner's view on the subject of patients waiting to see the doctor.

  17. wait and wipe

    African Journals Online (AJOL)

    and wipe strategy” as an alternative to circumcision for HIV prevention. In this paper, we argue that waiting for ten minutes and wiping with a dry cloth does not prevent men from becoming infected by HIV. We ... HIV infected despite having reported no sex or 100% condom .... In a qualitative study conducted in Kenya, men.

  18. Challenging "Waiting for Superman"

    Science.gov (United States)

    Bruhn, Molle

    2014-01-01

    A group of New York City public school teachers, angry about the depiction of public schools in 'Waiting for Superman," decide to make their own film about the realities of the current education reform movement. They persevered even though they had no budget when they started and lacked a background in filmmaking. "The Inconvenient Truth…

  19. Colour Consideration for Waiting areas in hospitals

    Science.gov (United States)

    Zraati, Parisa

    2012-08-01

    Colour is one the most important factors in the nature that can have some affects on human behaviour. Many years ago, it was proven that using colour in public place can have some affect on the users. Depend of the darkness and lightness; it can be vary from positive to negative. The research will mainly focus on the colour and psychological influences and physical factors. The statement of problem in this research is what is impact of colour usually applied to waiting area? The overall aim of the study is to explore the visual environment of hospitals and to manage the colour psychological effect of the hospital users in the waiting area by creating a comfortable, pleasant and cozy environment for users while spend their time in waiting areas. The analysisconcentrate on satisfaction and their interesting regarding applied colour in two private hospital waiting area in Malaysia.

  20. Impact of UCSF criteria according to pre- and post-OLT tumor features: analysis of 479 patients listed for HCC with a short waiting time.

    Science.gov (United States)

    Decaens, Thomas; Roudot-Thoraval, Françoise; Hadni-Bresson, Solange; Meyer, Carole; Gugenheim, Jean; Durand, Francois; Bernard, Pierre-Henri; Boillot, Olivier; Sulpice, Laurent; Calmus, Yvon; Hardwigsen, Jean; Ducerf, Christian; Pageaux, Georges-Philippe; Dharancy, Sebastien; Chazouilleres, Olivier; Cherqui, Daniel; Duvoux, Christophe

    2006-12-01

    Orthotopic liver transplantation (OLT) indication for hepatocellular carcinoma (HCC) is currently based on the Milan criteria. The University of California, San Francisco (UCSF) recently proposed an expansion of the selection criteria according to tumors characteristics on the explanted liver. This study: 1) assessed the validity of these criteria in an independent large series and 2) tested for the usefulness of these criteria when applied to pre-OLT tumor evaluation. Between 1985 and 1998, 479 patients were listed for liver transplantation (LT) for HCC and 467 were transplanted. According to pre-OLT (imaging at date of listing) or post-OLT (explanted liver) tumor characteristics, patients were retrospectively classified according to both the Milan and UCSF criteria. The 5-yr survival statistics were assessed by the Kaplan-Meier method and compared by the log-rank test. Pre-OLT UCSF criteria were analyzed according to an intention-to-treat principle. Based on the pre-OLT evaluation, 279 patients were Milan+, 44 patients were UCSF+ but Milan- (subgroup of patients that might benefit from the expansion), and 145 patients were UCSF- and Milan-. With a short median waiting time of 4 months, 5-yr survival was 60.1 +/- 3.0%, 45.6 +/- 7.8%, and 34.7 +/- 4.0%, respectively (P OLT evaluation, the UCSF criteria are associated with a 5-yr survival below 50%. Their applicability is therefore limited, despite similar survival rates compared to the Milan criteria, when the explanted liver is taken into account.

  1. Parareal algorithms with local time-integrators for time fractional differential equations

    Science.gov (United States)

    Wu, Shu-Lin; Zhou, Tao

    2018-04-01

    It is challenge work to design parareal algorithms for time-fractional differential equations due to the historical effect of the fractional operator. A direct extension of the classical parareal method to such equations will lead to unbalance computational time in each process. In this work, we present an efficient parareal iteration scheme to overcome this issue, by adopting two recently developed local time-integrators for time fractional operators. In both approaches, one introduces auxiliary variables to localized the fractional operator. To this end, we propose a new strategy to perform the coarse grid correction so that the auxiliary variables and the solution variable are corrected separately in a mixed pattern. It is shown that the proposed parareal algorithm admits robust rate of convergence. Numerical examples are presented to support our conclusions.

  2. A novel time-domain signal processing algorithm for real time ventricular fibrillation detection

    International Nuclear Information System (INIS)

    Monte, G E; Scarone, N C; Liscovsky, P O; Rotter, P

    2011-01-01

    This paper presents an application of a novel algorithm for real time detection of ECG pathologies, especially ventricular fibrillation. It is based on segmentation and labeling process of an oversampled signal. After this treatment, analyzing sequence of segments, global signal behaviours are obtained in the same way like a human being does. The entire process can be seen as a morphological filtering after a smart data sampling. The algorithm does not require any ECG digital signal pre-processing, and the computational cost is low, so it can be embedded into the sensors for wearable and permanent applications. The proposed algorithms could be the input signal description to expert systems or to artificial intelligence software in order to detect other pathologies.

  3. A novel time-domain signal processing algorithm for real time ventricular fibrillation detection

    Science.gov (United States)

    Monte, G. E.; Scarone, N. C.; Liscovsky, P. O.; Rotter S/N, P.

    2011-12-01

    This paper presents an application of a novel algorithm for real time detection of ECG pathologies, especially ventricular fibrillation. It is based on segmentation and labeling process of an oversampled signal. After this treatment, analyzing sequence of segments, global signal behaviours are obtained in the same way like a human being does. The entire process can be seen as a morphological filtering after a smart data sampling. The algorithm does not require any ECG digital signal pre-processing, and the computational cost is low, so it can be embedded into the sensors for wearable and permanent applications. The proposed algorithms could be the input signal description to expert systems or to artificial intelligence software in order to detect other pathologies.

  4. Space-time spectral collocation algorithm for solving time-fractional Tricomi-type equations

    Directory of Open Access Journals (Sweden)

    Abdelkawy M.A.

    2016-01-01

    Full Text Available We introduce a new numerical algorithm for solving one-dimensional time-fractional Tricomi-type equations (T-FTTEs. We used the shifted Jacobi polynomials as basis functions and the derivatives of fractional is evaluated by the Caputo definition. The shifted Jacobi Gauss-Lobatt algorithm is used for the spatial discretization, while the shifted Jacobi Gauss-Radau algorithmis applied for temporal approximation. Substituting these approximations in the problem leads to a system of algebraic equations that greatly simplifies the problem. The proposed algorithm is successfully extended to solve the two-dimensional T-FTTEs. Extensive numerical tests illustrate the capability and high accuracy of the proposed methodologies.

  5. Real time equilibrium reconstruction algorithm in EAST tokamak

    International Nuclear Information System (INIS)

    Wang Huazhong; Luo Jiarong; Huang Qinchao

    2004-01-01

    The EAST (HT-7U) superconducting tokamak is a national project of China on fusion research, with a capability of long-pulse (∼1000 s) operation. In order to realize a long-duration steady-state operation of EAST, some significant capability of real-time control is required. It would be very crucial to obtain the current profile parameters and the plasma shapes in real time by a flexible control system. As those discharge parameters cannot be directly measured, so a current profile consistent with the magnetohydrodynamic equilibrium should be evaluated from external magnetic measurements, based on a linearized iterative least square method, which can meet the requirements of the measurements. The arithmetic that the EFIT (equilibrium fitting code) is used for reference will be given in this paper and the computational efforts are reduced by parameterizing the current profile linearly in terms of a number of physical parameters. In order to introduce this reconstruction algorithm clearly, the main hardware design will be listed also. (authors)

  6. Cable Damage Detection System and Algorithms Using Time Domain Reflectometry

    Energy Technology Data Exchange (ETDEWEB)

    Clark, G A; Robbins, C L; Wade, K A; Souza, P R

    2009-03-24

    This report describes the hardware system and the set of algorithms we have developed for detecting damage in cables for the Advanced Development and Process Technologies (ADAPT) Program. This program is part of the W80 Life Extension Program (LEP). The system could be generalized for application to other systems in the future. Critical cables can undergo various types of damage (e.g. short circuits, open circuits, punctures, compression) that manifest as changes in the dielectric/impedance properties of the cables. For our specific problem, only one end of the cable is accessible, and no exemplars of actual damage are available. This work addresses the detection of dielectric/impedance anomalies in transient time domain reflectometry (TDR) measurements on the cables. The approach is to interrogate the cable using time domain reflectometry (TDR) techniques, in which a known pulse is inserted into the cable, and reflections from the cable are measured. The key operating principle is that any important cable damage will manifest itself as an electrical impedance discontinuity that can be measured in the TDR response signal. Machine learning classification algorithms are effectively eliminated from consideration, because only a small number of cables is available for testing; so a sufficient sample size is not attainable. Nonetheless, a key requirement is to achieve very high probability of detection and very low probability of false alarm. The approach is to compare TDR signals from possibly damaged cables to signals or an empirical model derived from reference cables that are known to be undamaged. This requires that the TDR signals are reasonably repeatable from test to test on the same cable, and from cable to cable. Empirical studies show that the repeatability issue is the 'long pole in the tent' for damage detection, because it is has been difficult to achieve reasonable repeatability. This one factor dominated the project. The two-step model

  7. Heuristics for no-wait flow shop scheduling problem

    Directory of Open Access Journals (Sweden)

    Kewal Krishan Nailwal

    2016-09-01

    Full Text Available No-wait flow shop scheduling refers to continuous flow of jobs through different machines. The job once started should have the continuous processing through the machines without wait. This situation occurs when there is a lack of an intermediate storage between the processing of jobs on two consecutive machines. The problem of no-wait with the objective of minimizing makespan in flow shop scheduling is NP-hard; therefore the heuristic algorithms are the key to solve the problem with optimal solution or to approach nearer to optimal solution in simple manner. The paper describes two heuristics, one constructive and an improvement heuristic algorithm obtained by modifying the constructive one for sequencing n-jobs through m-machines in a flow shop under no-wait constraint with the objective of minimizing makespan. The efficiency of the proposed heuristic algorithms is tested on 120 Taillard’s benchmark problems found in the literature against the NEH under no-wait and the MNEH heuristic for no-wait flow shop problem. The improvement heuristic outperforms all heuristics on the Taillard’s instances by improving the results of NEH by 27.85%, MNEH by 22.56% and that of the proposed constructive heuristic algorithm by 24.68%. To explain the computational process of the proposed algorithm, numerical illustrations are also given in the paper. Statistical tests of significance are done in order to draw the conclusions.

  8. A general algorithm for computing distance transforms in linear time

    NARCIS (Netherlands)

    Meijster, A.; Roerdink, J.B.T.M.; Hesselink, W.H.; Goutsias, J; Vincent, L; Bloomberg, DS

    2000-01-01

    A new general algorithm fur computing distance transforms of digital images is presented. The algorithm consists of two phases. Both phases consist of two scans, a forward and a backward scan. The first phase scans the image column-wise, while the second phase scans the image row-wise. Since the

  9. Algorithms

    Indian Academy of Sciences (India)

    to as 'divide-and-conquer'. Although there has been a large effort in realizing efficient algorithms, there are not many universally accepted algorithm design paradigms. In this article, we illustrate algorithm design techniques such as balancing, greedy strategy, dynamic programming strategy, and backtracking or traversal of ...

  10. Efficient On-the-fly Algorithms for the Analysis of Timed Games

    DEFF Research Database (Denmark)

    Cassez, Franck; David, Alexandre; Fleury, Emmanuel

    2005-01-01

    In this paper, we propose the first efficient on-the-fly algorithm for solving games based on timed game automata with respect to reachability and safety properties The algorithm we propose is a symbolic extension of the on-the-fly algorithm suggested by Liu & Smolka [15] for linear-time model-ch...... symbolic algorithm are proposed as well as methods for obtaining time-optimal winning strategies (for reachability games). Extensive evaluation of an experimental implementation of the algorithm yields very encouraging performance results.......In this paper, we propose the first efficient on-the-fly algorithm for solving games based on timed game automata with respect to reachability and safety properties The algorithm we propose is a symbolic extension of the on-the-fly algorithm suggested by Liu & Smolka [15] for linear-time model...

  11. Economic performance of lactating dairy cows submitted for first service timed artificial insemination after a voluntary waiting period of 60 or 88 days.

    Science.gov (United States)

    Stangaferro, M L; Wijma, R; Masello, M; Thomas, Mark J; Giordano, J O

    2018-05-23

    The objective of this study was to evaluate the economic performance of dairy cows managed with a voluntary waiting period (VWP) of 60 or 88 d. A secondary objective was estimating variation in cash flow under different input pricing scenarios through stochastic Monte Carlo simulations. Lactating Holstein cows from 3 commercial farms were blocked by parity group and total milk yield in their previous lactation and then randomly assigned to a VWP of 60 (VWP60; n = 1,352) or 88 d (VWP88; n = 1,359). All cows received timed-artificial insemination (TAI) for first service after synchronization of ovulation with the Double-Ovsynch protocol. For second and greater services, cows received artificial insemination (AI) after detection of estrus or the Ovsynch protocol initiated 32 ± 3 d after AI. Two analyses were performed: (1) cash flow per cow for the calving interval of the experimental lactation and (2) cash flow per slot occupied by each cow enrolled in the experiment for an 18-mo period after calving in the experimental lactation. Extending the VWP from 60 to 88 d delayed time to pregnancy during lactation (~20 d) and increased the risk of leaving the herd for multiparous cows (hazard ratio = 1.21). As a result, a smaller proportion of multiparous cows calved again and had a subsequent lactation (-6%). The shift in time to pregnancy combined with the herd exit dynamics resulted in longer lactation length for primiparous (22 d) but not multiparous cows. Longer lactations led to greater milk income over feed cost and a tendency for greater cash flow during the experimental lactation for primiparous but not multiparous cows in the VWP88 group. On the other hand, profitability per slot for the 18-mo period was numerically greater ($68 slot/18 mo) for primiparous cows but numerically reduced (-$85 slot/18 mo) for multiparous cows in the VWP88 treatment. For primiparous cows most of the difference in cash flow was explained by replacement cost, whereas for multiparous

  12. Iran - waiting and watching

    International Nuclear Information System (INIS)

    Malhotra, T. C.

    2007-01-01

    Global oil companies are reported to be divided on the issue of possible energy deals in Iran. Some companies may adopt wait and watch policy before singing a fresh deal with Iran, but there are some oil companies, those are still interested to sign a deal with Iran, despite the risks, even as Tehran decided to expand its uranium enrichment programme rather than complying with a UN Security Council ultimatum to freeze it, which clears the path for further harsher sanctions (author) (ml)

  13. An Empirical Derivation of the Run Time of the Bubble Sort Algorithm.

    Science.gov (United States)

    Gonzales, Michael G.

    1984-01-01

    Suggests a moving pictorial tool to help teach principles in the bubble sort algorithm. Develops such a tool applied to an unsorted list of numbers and describes a method to derive the run time of the algorithm. The method can be modified to run the times of various other algorithms. (JN)

  14. Waiting list in a public health facility in Santiago, Chile

    Directory of Open Access Journals (Sweden)

    Alejandro Letelier

    2014-07-01

    Full Text Available Introduction Waiting lists are a well-known problem in public healthcare systems worldwide. For instance, England had over one million people in waiting lists for elective surgical procedures in 2000. Spain had over 360 000 patients in surgical waiting lists in 2007. Chile has been trying to manage waiting times through the GES (Explicit Guarantees in Healthcare plan, which was established by the Chilean government in 2005. Waiting lists for the guaranteed-care diseases in the GES plan had 380 000 patients at the beginning of 2010, and that number was reduced to zero in 2011. Internationally, there are some descriptive studies about waiting lists that focus on variables such as waiting times and number of patients in the list. In Chile, however, this type of study is lacking. Purpose This study aims to describe the characteristics of waiting lists for medical specialties between April and October 2011. It also aims to identify the components of management models in public healthcare centers, and to identify and analyze waiting-time frames of patients referred to a secondary or tertiary healthcare public center from a public primary healthcare center. Methods A descriptive cross-sectional study of the waiting list for first-time consultations for medical specialties was carried out. Referred patients were described and grouped using indicators of access to healthcare and waiting time between April and October 2011. Each consultation request or referral of a new patient was included in the waiting list and analyzed. Results There were 15 935 requests for consultations; 5 717 requests were resolved, and 8 544 were not (54% of the total requests for consultation. There was a mean waiting time of 498 days for non-resolved requests for consultation, and a mean of 141 days for resolved requests. The specialties in highest demand were orthopedic surgery and ophthalmology. The main waiting-list management processes were referral and reception of requests

  15. Time synchronization algorithm of distributed system based on server time-revise and workstation self-adjust

    International Nuclear Information System (INIS)

    Zhou Shumin; Sun Yamin; Tang Bin

    2007-01-01

    In order to enhance the time synchronization quality of the distributed system, a time synchronization algorithm of distributed system based on server time-revise and workstation self-adjust is proposed. The time-revise cycle and self-adjust process is introduced in the paper. The algorithm reduces network flow effectively and enhances the quality of clock-synchronization. (authors)

  16. Time complexity and linear-time approximation of the ancient two-machine flow shop

    NARCIS (Netherlands)

    Rote, G.; Woeginger, G.J.

    1998-01-01

    We consider the scheduling problems F2¿Cmax and F2|no-wait|Cmax, i.e. makespan minimization in a two-machine flow shop, with and without no wait in process. For both problems solution algorithms based on sorting with O(n log n) running time are known, where n denotes the number of jobs. [1, 2]. We

  17. No-Wait Flexible Flow Shop Scheduling with Due Windows

    Directory of Open Access Journals (Sweden)

    Rong-Hwa Huang

    2015-01-01

    Full Text Available To improve capacity and reduce processing time, the flow shop with multiprocessors (FSMP system is commonly used in glass, steel, and semiconductor production. No-wait FSMP is a modern production system that responds to periods when zero work is required in process production. The production process must be continuous and uninterrupted. Setup time must also be considered. Just-in-time (JIT production is very popular in industry, and timely delivery is important to customer satisfaction. Therefore, it is essential to consider the time window constraint, which is also very complex. This study focuses on a no-wait FSMP problem with time window constraint. An improved ant colony optimization (ACO, known as ant colony optimization with flexible update (ACOFU, is developed to solve the problem. The results demonstrate that ACOFU is more effective and robust than ACO when applied to small-scale problems. ACOFU has superior solution capacity and robustness when applied to large-scale problems. Therefore, this study concludes that the proposed algorithm ACOFU performs excellently when applied to the scheduling problem discussed in this study.

  18. Effectiveness and acceptance of a web-based depression intervention during waiting time for outpatient psychotherapy: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Grünzig, Sasha-Denise; Baumeister, Harald; Bengel, Jürgen; Ebert, David; Krämer, Lena

    2018-05-22

    Due to limited resources, waiting periods for psychotherapy are often long and burdening for those in need of treatment and the health care system. In order to bridge the gap between initial contact and the beginning of psychotherapy, web-based interventions can be applied. The implementation of a web-based depression intervention during waiting periods has the potential to reduce depressive symptoms and enhance well-being in depressive individuals waiting for psychotherapy. In a two-arm randomized controlled trial, effectiveness and acceptance of a guided web-based intervention for depressive individuals on a waitlist for psychotherapy are evaluated. Participants are recruited in several German outpatient clinics. All those contacting the outpatient clinics with the wish to enter psychotherapy receive study information and a depression screening. Those adults (age ≥ 18) with depressive symptoms above cut-off (CES-D scale > 22) and internet access are randomized to either intervention condition (treatment as usual and immediate access to the web-based intervention) or waiting control condition (treatment as usual and delayed access to the web-based intervention). At three points of assessment (baseline, post-treatment, 3-months-follow-up) depressive symptoms and secondary outcomes, such as quality of life, attitudes towards psychotherapy and web-based interventions and adverse events are assessed. Additionally, participants' acceptance of the web-based intervention is evaluated, using measures of intervention adherence and satisfaction. This study investigates a relevant setting for the implementation of web-based interventions, potentially improving the provision of psychological health care. The results of this study contribute to the evaluation of innovative and resource-preserving health care models for outpatient psychological treatment. This trial has been registered on 13 February 2017 in the German clinical trials register (DRKS); registration

  19. 'Waiting for' and 'waiting in' public and private hospitals: a qualitative study of patient trust in South Australia.

    Science.gov (United States)

    Ward, Paul R; Rokkas, Philippa; Cenko, Clinton; Pulvirenti, Mariastella; Dean, Nicola; Carney, A Simon; Meyer, Samantha

    2017-05-05

    Waiting times for hospital appointments, treatment and/or surgery have become a major political and health service problem, leading to national maximum waiting times and policies to reduce waiting times. Quantitative studies have documented waiting times for various types of surgery and longer waiting times in public vs private hospitals. However, very little qualitative research has explored patient experiences of waiting, how this compares between public and private hospitals, and the implications for trust in hospitals and healthcare professionals. The aim of this paper is to provide a deep understanding of the impact of waiting times on patient trust in public and private hospitals. A qualitative study in South Australia, including 36 in-depth interviews (18 from public and 18 from private hospitals). Data collection occurred in 2012-13, and data were analysed using pre-coding, followed by conceptual and theoretical categorisation. Participants differentiated between experiences of 'waiting for' (e.g. for specialist appointments and surgery) and 'waiting in' (e.g. in emergency departments and outpatient clinics) public and private hospitals. Whilst 'waiting for' public hospitals was longer than private hospitals, this was often justified and accepted by public patients (e.g. due to reduced government funding), therefore it did not lead to distrust of public hospitals. Private patients had shorter 'waiting for' hospital services, increasing their trust in private hospitals and distrust of public hospitals. Public patients also recounted many experiences of longer 'waiting in' public hospitals, leading to frustration and anxiety, although they rarely blamed or distrusted the doctors or nurses, instead blaming an underfunded system and over-worked staff. Doctors and nurses were seen to be doing their best, and therefore trustworthy. Although public patients experienced longer 'waiting for' and 'waiting in' public hospitals, it did not lead to widespread distrust

  20. Optimal Research and Numerical Simulation for Scheduling No-Wait Flow Shop in Steel Production

    Directory of Open Access Journals (Sweden)

    Huawei Yuan

    2013-01-01

    Full Text Available This paper considers the m-machine flow shop scheduling problem with the no-wait constraint to minimize total completion time which is the typical model in steel production. First, the asymptotic optimality of the Shortest Processing Time (SPT first rule is proven for this problem. To further evaluate the performance of the algorithm, a new lower bound with performance guarantee is designed. At the end of the paper, numerical simulations show the effectiveness of the proposed algorithm and lower bound.

  1. Ramsey waits: allocating public health service resources when there is rationing by waiting.

    Science.gov (United States)

    Gravelle, Hugh; Siciliani, Luigi

    2008-09-01

    The optimal allocation of a public health care budget across treatments must take account of the way in which care is rationed within treatments since this will affect their marginal value. We investigate the optimal allocation rules for public health care systems where user charges are fixed and care is rationed by waiting. The optimal waiting time is higher for treatments with demands more elastic to waiting time, higher costs, lower charges, smaller marginal welfare loss from waiting by treated patients, and smaller marginal welfare losses from under-consumption of care. The results hold for a wide range of welfarist and non-welfarist objective functions and for systems in which there is also a private health care sector. They imply that allocation rules based purely on cost effectiveness ratios are suboptimal because they assume that there is no rationing within treatments.

  2. Time scale algorithm: Definition of ensemble time and possible uses of the Kalman filter

    Science.gov (United States)

    Tavella, Patrizia; Thomas, Claudine

    1990-01-01

    The comparative study of two time scale algorithms, devised to satisfy different but related requirements, is presented. They are ALGOS(BIPM), producing the international reference TAI at the Bureau International des Poids et Mesures, and AT1(NIST), generating the real-time time scale AT1 at the National Institute of Standards and Technology. In each case, the time scale is a weighted average of clock readings, but the weight determination and the frequency prediction are different because they are adapted to different purposes. The possibility of using a mathematical tool, such as the Kalman filter, together with the definition of the time scale as a weighted average, is also analyzed. Results obtained by simulation are presented.

  3. Real time algorithms for sharp wave ripple detection.

    Science.gov (United States)

    Sethi, Ankit; Kemere, Caleb

    2014-01-01

    Neural activity during sharp wave ripples (SWR), short bursts of co-ordinated oscillatory activity in the CA1 region of the rodent hippocampus, is implicated in a variety of memory functions from consolidation to recall. Detection of these events in an algorithmic framework, has thus far relied on simple thresholding techniques with heuristically derived parameters. This study is an investigation into testing and improving the current methods for detection of SWR events in neural recordings. We propose and profile methods to reduce latency in ripple detection. Proposed algorithms are tested on simulated ripple data. The findings show that simple realtime algorithms can improve upon existing power thresholding methods and can detect ripple activity with latencies in the range of 10-20 ms.

  4. A polynomial time biclustering algorithm for finding approximate expression patterns in gene expression time series

    Directory of Open Access Journals (Sweden)

    Madeira Sara C

    2009-06-01

    Full Text Available Abstract Background The ability to monitor the change in expression patterns over time, and to observe the emergence of coherent temporal responses using gene expression time series, obtained from microarray experiments, is critical to advance our understanding of complex biological processes. In this context, biclustering algorithms have been recognized as an important tool for the discovery of local expression patterns, which are crucial to unravel potential regulatory mechanisms. Although most formulations of the biclustering problem are NP-hard, when working with time series expression data the interesting biclusters can be restricted to those with contiguous columns. This restriction leads to a tractable problem and enables the design of efficient biclustering algorithms able to identify all maximal contiguous column coherent biclusters. Methods In this work, we propose e-CCC-Biclustering, a biclustering algorithm that finds and reports all maximal contiguous column coherent biclusters with approximate expression patterns in time polynomial in the size of the time series gene expression matrix. This polynomial time complexity is achieved by manipulating a discretized version of the original matrix using efficient string processing techniques. We also propose extensions to deal with missing values, discover anticorrelated and scaled expression patterns, and different ways to compute the errors allowed in the expression patterns. We propose a scoring criterion combining the statistical significance of expression patterns with a similarity measure between overlapping biclusters. Results We present results in real data showing the effectiveness of e-CCC-Biclustering and its relevance in the discovery of regulatory modules describing the transcriptomic expression patterns occurring in Saccharomyces cerevisiae in response to heat stress. In particular, the results show the advantage of considering approximate patterns when compared to state of

  5. Linear-time general decoding algorithm for the surface code

    Science.gov (United States)

    Darmawan, Andrew S.; Poulin, David

    2018-05-01

    A quantum error correcting protocol can be substantially improved by taking into account features of the physical noise process. We present an efficient decoder for the surface code which can account for general noise features, including coherences and correlations. We demonstrate that the decoder significantly outperforms the conventional matching algorithm on a variety of noise models, including non-Pauli noise and spatially correlated noise. The algorithm is based on an approximate calculation of the logical channel using a tensor-network description of the noisy state.

  6. Time Reversal Reconstruction Algorithm Based on PSO Optimized SVM Interpolation for Photoacoustic Imaging

    Directory of Open Access Journals (Sweden)

    Mingjian Sun

    2015-01-01

    Full Text Available Photoacoustic imaging is an innovative imaging technique to image biomedical tissues. The time reversal reconstruction algorithm in which a numerical model of the acoustic forward problem is run backwards in time is widely used. In the paper, a time reversal reconstruction algorithm based on particle swarm optimization (PSO optimized support vector machine (SVM interpolation method is proposed for photoacoustics imaging. Numerical results show that the reconstructed images of the proposed algorithm are more accurate than those of the nearest neighbor interpolation, linear interpolation, and cubic convolution interpolation based time reversal algorithm, which can provide higher imaging quality by using significantly fewer measurement positions or scanning times.

  7. A Note on "A polynomial-time algorithm for global value numbering"

    OpenAIRE

    Nabeezath, Saleena; Paleri, Vineeth

    2013-01-01

    Global Value Numbering(GVN) is a popular method for detecting redundant computations. A polynomial time algorithm for GVN is presented by Gulwani and Necula(2006). Here we present two limitations of this GVN algorithm due to which detection of certain kinds of redundancies can not be done using this algorithm. The first one is concerning the use of this algorithm in detecting some instances of the classical global common subexpressions, and the second is concerning its use in the detection of...

  8. A linear-time algorithm for Euclidean feature transform sets

    NARCIS (Netherlands)

    Hesselink, Wim H.

    2007-01-01

    The Euclidean distance transform of a binary image is the function that assigns to every pixel the Euclidean distance to the background. The Euclidean feature transform is the function that assigns to every pixel the set of background pixels with this distance. We present an algorithm to compute the

  9. A linear time layout algorithm for business process models

    NARCIS (Netherlands)

    Gschwind, T.; Pinggera, J.; Zugal, S.; Reijers, H.A.; Weber, B.

    2014-01-01

    The layout of a business process model influences how easily it can beunderstood. Existing layout features in process modeling tools often rely on graph representations, but do not take the specific properties of business process models into account. In this paper, we propose an algorithm that is

  10. An improved exponential-time algorithm for k-SAT

    Czech Academy of Sciences Publication Activity Database

    Pudlák, Pavel

    2005-01-01

    Roč. 52, č. 3 (2005), s. 337-364 ISSN 0004-5411 R&D Projects: GA AV ČR(CZ) IAA1019901 Institutional research plan: CEZ:AV0Z10190503 Keywords : CNF sat isfiability * randomized algorithms Subject RIV: BA - General Mathematics Impact factor: 2.197, year: 2005

  11. Time-Delay System Identification Using Genetic Algorithm

    DEFF Research Database (Denmark)

    Yang, Zhenyu; Seested, Glen Thane

    2013-01-01

    problem through an identification approach using the real coded Genetic Algorithm (GA). The desired FOPDT/SOPDT model is directly identified based on the measured system's input and output data. In order to evaluate the quality and performance of this GA-based approach, the proposed method is compared...

  12. Low-Energy Real-Time OS Using Voltage Scheduling Algorithm for Variable Voltage Processors

    OpenAIRE

    Okuma, Takanori; Yasuura, Hiroto

    2001-01-01

    This paper presents a real-time OS based on $ mu $ITRON using proposed voltage scheduling algorithm for variable voltage processors which can vary supply voltage dynamically. The proposed voltage scheduling algorithms assign voltage level for each task dynamically in order to minimize energy consumption under timing constraints. Using the presented real-time OS, running tasks with low supply voltage leads to drastic energy reduction. In addition, the presented voltage scheduling algorithm is ...

  13. A Comparison of Evolutionary Algorithms for Tracking Time-Varying Recursive Systems

    Directory of Open Access Journals (Sweden)

    White Michael S

    2003-01-01

    Full Text Available A comparison is made of the behaviour of some evolutionary algorithms in time-varying adaptive recursive filter systems. Simulations show that an algorithm including random immigrants outperforms a more conventional algorithm using the breeder genetic algorithm as the mutation operator when the time variation is discontinuous, but neither algorithm performs well when the time variation is rapid but smooth. To meet this deficit, a new hybrid algorithm which uses a hill climber as an additional genetic operator, applied for several steps at each generation, is introduced. A comparison is made of the effect of applying the hill climbing operator a few times to all members of the population or a larger number of times solely to the best individual; it is found that applying to the whole population yields the better results, substantially improved compared with those obtained using earlier methods.

  14. Algorithms

    Indian Academy of Sciences (India)

    ticians but also forms the foundation of computer science. Two ... with methods of developing algorithms for solving a variety of problems but ... applications of computers in science and engineer- ... numerical calculus are as important. We will ...

  15. Protocol to Exploit Waiting Resources for UASNs

    Directory of Open Access Journals (Sweden)

    Li-Ling Hung

    2016-03-01

    Full Text Available The transmission speed of acoustic waves in water is much slower than that of radio waves in terrestrial wireless sensor networks. Thus, the propagation delay in underwater acoustic sensor networks (UASN is much greater. Longer propagation delay leads to complicated communication and collision problems. To solve collision problems, some studies have proposed waiting mechanisms; however, long waiting mechanisms result in low bandwidth utilization. To improve throughput, this study proposes a slotted medium access control protocol to enhance bandwidth utilization in UASNs. The proposed mechanism increases communication by exploiting temporal and spatial resources that are typically idle in order to protect communication against interference. By reducing wait time, network performance and energy consumption can be improved. A performance evaluation demonstrates that when the data packets are large or sensor deployment is dense, the energy consumption of proposed protocol is less than that of existing protocols as well as the throughput is higher than that of existing protocols.

  16. Intermediate view reconstruction using adaptive disparity search algorithm for real-time 3D processing

    Science.gov (United States)

    Bae, Kyung-hoon; Park, Changhan; Kim, Eun-soo

    2008-03-01

    In this paper, intermediate view reconstruction (IVR) using adaptive disparity search algorithm (ASDA) is for realtime 3-dimensional (3D) processing proposed. The proposed algorithm can reduce processing time of disparity estimation by selecting adaptive disparity search range. Also, the proposed algorithm can increase the quality of the 3D imaging. That is, by adaptively predicting the mutual correlation between stereo images pair using the proposed algorithm, the bandwidth of stereo input images pair can be compressed to the level of a conventional 2D image and a predicted image also can be effectively reconstructed using a reference image and disparity vectors. From some experiments, stereo sequences of 'Pot Plant' and 'IVO', it is shown that the proposed algorithm improves the PSNRs of a reconstructed image to about 4.8 dB by comparing with that of conventional algorithms, and reduces the Synthesizing time of a reconstructed image to about 7.02 sec by comparing with that of conventional algorithms.

  17. Real-time algorithm for acoustic imaging with a microphone array.

    Science.gov (United States)

    Huang, Xun

    2009-05-01

    Acoustic phased array has become an important testing tool in aeroacoustic research, where the conventional beamforming algorithm has been adopted as a classical processing technique. The computation however has to be performed off-line due to the expensive cost. An innovative algorithm with real-time capability is proposed in this work. The algorithm is similar to a classical observer in the time domain while extended for the array processing to the frequency domain. The observer-based algorithm is beneficial mainly for its capability of operating over sampling blocks recursively. The expensive experimental time can therefore be reduced extensively since any defect in a testing can be corrected instantaneously.

  18. Time series classification using k-Nearest neighbours, Multilayer Perceptron and Learning Vector Quantization algorithms

    Directory of Open Access Journals (Sweden)

    Jiří Fejfar

    2012-01-01

    Full Text Available We are presenting results comparison of three artificial intelligence algorithms in a classification of time series derived from musical excerpts in this paper. Algorithms were chosen to represent different principles of classification – statistic approach, neural networks and competitive learning. The first algorithm is a classical k-Nearest neighbours algorithm, the second algorithm is Multilayer Perceptron (MPL, an example of artificial neural network and the third one is a Learning Vector Quantization (LVQ algorithm representing supervised counterpart to unsupervised Self Organizing Map (SOM.After our own former experiments with unlabelled data we moved forward to the data labels utilization, which generally led to a better accuracy of classification results. As we need huge data set of labelled time series (a priori knowledge of correct class which each time series instance belongs to, we used, with a good experience in former studies, musical excerpts as a source of real-world time series. We are using standard deviation of the sound signal as a descriptor of a musical excerpts volume level.We are describing principle of each algorithm as well as its implementation briefly, giving links for further research. Classification results of each algorithm are presented in a confusion matrix showing numbers of misclassifications and allowing to evaluate overall accuracy of the algorithm. Results are compared and particular misclassifications are discussed for each algorithm. Finally the best solution is chosen and further research goals are given.

  19. Micro-Doppler Signal Time-Frequency Algorithm Based on STFRFT

    Directory of Open Access Journals (Sweden)

    Cunsuo Pang

    2016-09-01

    Full Text Available This paper proposes a time-frequency algorithm based on short-time fractional order Fourier transformation (STFRFT for identification of a complicated movement targets. This algorithm, consisting of a STFRFT order-changing and quick selection method, is effective in reducing the computation load. A multi-order STFRFT time-frequency algorithm is also developed that makes use of the time-frequency feature of each micro-Doppler component signal. This algorithm improves the estimation accuracy of time-frequency curve fitting through multi-order matching. Finally, experiment data were used to demonstrate STFRFT’s performance in micro-Doppler time-frequency analysis. The results validated the higher estimate accuracy of the proposed algorithm. It may be applied to an LFM (Linear frequency modulated pulse radar, SAR (Synthetic aperture radar, or ISAR (Inverse synthetic aperture radar, for improving the probability of target recognition.

  20. Micro-Doppler Signal Time-Frequency Algorithm Based on STFRFT.

    Science.gov (United States)

    Pang, Cunsuo; Han, Yan; Hou, Huiling; Liu, Shengheng; Zhang, Nan

    2016-09-24

    This paper proposes a time-frequency algorithm based on short-time fractional order Fourier transformation (STFRFT) for identification of a complicated movement targets. This algorithm, consisting of a STFRFT order-changing and quick selection method, is effective in reducing the computation load. A multi-order STFRFT time-frequency algorithm is also developed that makes use of the time-frequency feature of each micro-Doppler component signal. This algorithm improves the estimation accuracy of time-frequency curve fitting through multi-order matching. Finally, experiment data were used to demonstrate STFRFT's performance in micro-Doppler time-frequency analysis. The results validated the higher estimate accuracy of the proposed algorithm. It may be applied to an LFM (Linear frequency modulated) pulse radar, SAR (Synthetic aperture radar), or ISAR (Inverse synthetic aperture radar), for improving the probability of target recognition.

  1. A numerical solution for the multi-server queue with hyper-exponential service times

    NARCIS (Netherlands)

    de Smit, J.H.A.

    1983-01-01

    In this paper we present a numerical method for the queue GI/H2/s, which is based on general results for GI/Hm/s. We give a complete description of the algorithm which yields exact results for the steady distributions of the actual waiting time, the virtual waiting time and the number of customers

  2. Algorithms

    Indian Academy of Sciences (India)

    algorithm design technique called 'divide-and-conquer'. One of ... Turtle graphics, September. 1996. 5. ... whole list named 'PO' is a pointer to the first element of the list; ..... Program for computing matrices X and Y and placing the result in C *).

  3. Algorithms

    Indian Academy of Sciences (India)

    algorithm that it is implicitly understood that we know how to generate the next natural ..... Explicit comparisons are made in line (1) where maximum and minimum is ... It can be shown that the function T(n) = 3/2n -2 is the solution to the above ...

  4. Lower bounds on the run time of the univariate marginal distribution algorithm on OneMax

    DEFF Research Database (Denmark)

    Krejca, Martin S.; Witt, Carsten

    2017-01-01

    The Univariate Marginal Distribution Algorithm (UMDA), a popular estimation of distribution algorithm, is studied from a run time perspective. On the classical OneMax benchmark function, a lower bound of Ω(μ√n + n log n), where μ is the population size, on its expected run time is proved...... values maintained by the algorithm, including carefully designed potential functions. These techniques may prove useful in advancing the field of run time analysis for estimation of distribution algorithms in general........ This is the first direct lower bound on the run time of the UMDA. It is stronger than the bounds that follow from general black-box complexity theory and is matched by the run time of many evolutionary algorithms. The results are obtained through advanced analyses of the stochastic change of the frequencies of bit...

  5. Accuracy evaluation of a new real-time continuous glucose monitoring algorithm in hypoglycemia

    DEFF Research Database (Denmark)

    Mahmoudi, Zeinab; Jensen, Morten Hasselstrøm; Johansen, Mette Dencker

    2014-01-01

    UNLABELLED: Abstract Background: The purpose of this study was to evaluate the performance of a new continuous glucose monitoring (CGM) calibration algorithm and to compare it with the Guardian(®) REAL-Time (RT) (Medtronic Diabetes, Northridge, CA) calibration algorithm in hypoglycemia. SUBJECTS...... AND METHODS: CGM data were obtained from 10 type 1 diabetes patients undergoing insulin-induced hypoglycemia. Data were obtained in two separate sessions using the Guardian RT CGM device. Data from the same CGM sensor were calibrated by two different algorithms: the Guardian RT algorithm and a new calibration...... algorithm. The accuracy of the two algorithms was compared using four performance metrics. RESULTS: The median (mean) of absolute relative deviation in the whole range of plasma glucose was 20.2% (32.1%) for the Guardian RT calibration and 17.4% (25.9%) for the new calibration algorithm. The mean (SD...

  6. Efficient algorithms for approximate time separation of events

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    in the verification and analysis of asynchronous and concurrent systems. ...... Gunawardena J 1994 Timing analysis of digital circuits and the theory of min-max ... Williams T E 1994 Performance of iterative computation in self-timed rings.

  7. An Experimental Evaluation of Real-Time DVFS Scheduling Algorithms

    OpenAIRE

    Saha, Sonal

    2011-01-01

    Dynamic voltage and frequency scaling (DVFS) is an extensively studied energy manage- ment technique, which aims to reduce the energy consumption of computing platforms by dynamically scaling the CPU frequency. Real-Time DVFS (RT-DVFS) is a branch of DVFS, which reduces CPU energy consumption through DVFS, while at the same time ensures that task time constraints are satisfied by constructing appropriate real-time task schedules. The literature presents numerous RT-DVFS schedul...

  8. A real-time MTFC algorithm of space remote-sensing camera based on FPGA

    Science.gov (United States)

    Zhao, Liting; Huang, Gang; Lin, Zhe

    2018-01-01

    A real-time MTFC algorithm of space remote-sensing camera based on FPGA was designed. The algorithm can provide real-time image processing to enhance image clarity when the remote-sensing camera running on-orbit. The image restoration algorithm adopted modular design. The MTF measurement calculation module on-orbit had the function of calculating the edge extension function, line extension function, ESF difference operation, normalization MTF and MTFC parameters. The MTFC image filtering and noise suppression had the function of filtering algorithm and effectively suppressing the noise. The algorithm used System Generator to design the image processing algorithms to simplify the design structure of system and the process redesign. The image gray gradient dot sharpness edge contrast and median-high frequency were enhanced. The image SNR after recovery reduced less than 1 dB compared to the original image. The image restoration system can be widely used in various fields.

  9. Patients' perceptions of waiting for bariatric surgery: a qualitative study.

    Science.gov (United States)

    Gregory, Deborah M; Temple Newhook, Julia; Twells, Laurie K

    2013-10-18

    In Canada waiting lists for bariatric surgery are common, with wait times on average > 5 years. The meaning of waiting for bariatric surgery from the patients' perspective must be understood if health care providers are to act as facilitators in promoting satisfaction with care and quality care outcomes. The aims of this study were to explore patients' perceptions of waiting for bariatric surgery, the meaning and experience of waiting, the psychosocial and behavioral impact of waiting for treatment and identify health care provider and health system supportive measures that could potentially improve the waiting experience. Twenty-one women and six men engaged in in-depth interviews that were digitally recorded, transcribed verbatim and analysed using a grounded theory approach to data collection and analysis between June 2011 and April 2012. The data were subjected to re-analysis to identify perceived health care provider and health system barriers to accessing bariatric surgery. Thematic analysis identified inequity as a barrier to accessing bariatric surgery. Three areas of perceived inequity were identified from participants' accounts: socioeconomic inequity, regional inequity, and inequity related to waitlist prioritization. Although excited about their acceptance as candidates for surgery, the waiting period was described as stressful, anxiety provoking, and frustrating. Anger was expressed towards the health care system for the long waiting times. Participants identified the importance of health care provider and health system supports during the waiting period. Recommendations on how to improve the waiting experience included periodic updates from the surgeon's office about their position on the wait list; a counselor who specializes in helping people going through this surgery, dietitian support and further information on what to expect after surgery, among others. Patients' perceptions of accessing and waiting for bariatric surgery are shaped by perceived

  10. A real-time ECG data compression and transmission algorithm for an e-health device.

    Science.gov (United States)

    Lee, SangJoon; Kim, Jungkuk; Lee, Myoungho

    2011-09-01

    This paper introduces a real-time data compression and transmission algorithm between e-health terminals for a periodic ECGsignal. The proposed algorithm consists of five compression procedures and four reconstruction procedures. In order to evaluate the performance of the proposed algorithm, the algorithm was applied to all 48 recordings of MIT-BIH arrhythmia database, and the compress ratio (CR), percent root mean square difference (PRD), percent root mean square difference normalized (PRDN), rms, SNR, and quality score (QS) values were obtained. The result showed that the CR was 27.9:1 and the PRD was 2.93 on average for all 48 data instances with a 15% window size. In addition, the performance of the algorithm was compared to those of similar algorithms introduced recently by others. It was found that the proposed algorithm showed clearly superior performance in all 48 data instances at a compression ratio lower than 15:1, whereas it showed similar or slightly inferior PRD performance for a data compression ratio higher than 20:1. In light of the fact that the similarity with the original data becomes meaningless when the PRD is higher than 2, the proposed algorithm shows significantly better performance compared to the performance levels of other algorithms. Moreover, because the algorithm can compress and transmit data in real time, it can be served as an optimal biosignal data transmission method for limited bandwidth communication between e-health devices.

  11. Timing measurements of some tracking algorithms and suitability of FPGA's to improve the execution speed

    CERN Document Server

    Khomich, A; Kugel, A; Männer, R; Müller, M; Baines, J T M

    2003-01-01

    Some of track reconstruction algorithms which are common to all B-physics channels and standard RoI processing have been tested for execution time and assessed for suitability for speed-up by using FPGA coprocessor. The studies presented in this note were performed in the C/C++ framework, CTrig, which was the fullest set of algorithms available at the time of study For investigation of possible speed-up of algorithms most time consuming parts of TRT-LUT was implemented in VHDL for running in FPGA coprocessor board MPRACE. MPRACE (Reconfigurable Accelerator / Computing Engine) is an FPGA-Coprocessor based on Xilinx Virtex-2 FPGA and made as 64Bit/66MHz PCI card developed at the University of Mannheim. Timing measurements results for a TRT Full Scan algorithm executed on the MPRACE are presented here as well. The measurement results show a speed-up factor of ~2 for this algorithm.

  12. Algorithms

    Indian Academy of Sciences (India)

    will become clear in the next article when we discuss a simple logo like programming language. ... Rod B may be used as an auxiliary store. The problem is to find an algorithm which performs this task. ... No disks are moved from A to Busing C as auxiliary rod. • move _disk (A, C);. (No + l)th disk is moved from A to C directly ...

  13. Implementation of Real-Time Feedback Flow Control Algorithms on a Canonical Testbed

    Science.gov (United States)

    Tian, Ye; Song, Qi; Cattafesta, Louis

    2005-01-01

    This report summarizes the activities on "Implementation of Real-Time Feedback Flow Control Algorithms on a Canonical Testbed." The work summarized consists primarily of two parts. The first part summarizes our previous work and the extensions to adaptive ID and control algorithms. The second part concentrates on the validation of adaptive algorithms by applying them to a vibration beam test bed. Extensions to flow control problems are discussed.

  14. A fast readout algorithm for Cluster Counting/Timing drift chambers on a FPGA board

    Energy Technology Data Exchange (ETDEWEB)

    Cappelli, L. [Università di Cassino e del Lazio Meridionale (Italy); Creti, P.; Grancagnolo, F. [Istituto Nazionale di Fisica Nucleare, Lecce (Italy); Pepino, A., E-mail: Aurora.Pepino@le.infn.it [Istituto Nazionale di Fisica Nucleare, Lecce (Italy); Tassielli, G. [Istituto Nazionale di Fisica Nucleare, Lecce (Italy); Fermilab, Batavia, IL (United States); Università Marconi, Roma (Italy)

    2013-08-01

    A fast readout algorithm for Cluster Counting and Timing purposes has been implemented and tested on a Virtex 6 core FPGA board. The algorithm analyses and stores data coming from a Helium based drift tube instrumented by 1 GSPS fADC and represents the outcome of balancing between cluster identification efficiency and high speed performance. The algorithm can be implemented in electronics boards serving multiple fADC channels as an online preprocessing stage for drift chamber signals.

  15. Evaluation of Multiple Kernel Learning Algorithms for Crop Mapping Using Satellite Image Time-Series Data

    Science.gov (United States)

    Niazmardi, S.; Safari, A.; Homayouni, S.

    2017-09-01

    Crop mapping through classification of Satellite Image Time-Series (SITS) data can provide very valuable information for several agricultural applications, such as crop monitoring, yield estimation, and crop inventory. However, the SITS data classification is not straightforward. Because different images of a SITS data have different levels of information regarding the classification problems. Moreover, the SITS data is a four-dimensional data that cannot be classified using the conventional classification algorithms. To address these issues in this paper, we presented a classification strategy based on Multiple Kernel Learning (MKL) algorithms for SITS data classification. In this strategy, initially different kernels are constructed from different images of the SITS data and then they are combined into a composite kernel using the MKL algorithms. The composite kernel, once constructed, can be used for the classification of the data using the kernel-based classification algorithms. We compared the computational time and the classification performances of the proposed classification strategy using different MKL algorithms for the purpose of crop mapping. The considered MKL algorithms are: MKL-Sum, SimpleMKL, LPMKL and Group-Lasso MKL algorithms. The experimental tests of the proposed strategy on two SITS data sets, acquired by SPOT satellite sensors, showed that this strategy was able to provide better performances when compared to the standard classification algorithm. The results also showed that the optimization method of the used MKL algorithms affects both the computational time and classification accuracy of this strategy.

  16. Urgency coding as a dynamic tool in management of waiting lists for psychogeriatric nursing home care in The Netherlands

    NARCIS (Netherlands)

    Meiland, F. J. M.; Danse, J. A. C.; Wendte, J. F.; Gunning-Schepers, L. J.; Klazinga, N. S.

    2002-01-01

    Criteria are used to prioritise patients on waiting lists for health care services. This is also true for waiting lists for admission to psychogeriatric nursing homes. A patient's position on these latter waiting lists is determined by (changes in) urgency and waiting time. The present article

  17. Timing Metrics of Joint Timing and Carrier-Frequency Offset Estimation Algorithms for TDD-based OFDM systems

    NARCIS (Netherlands)

    Hoeksema, F.W.; Srinivasan, R.; Schiphorst, Roelof; Slump, Cornelis H.

    2004-01-01

    In joint timing and carrier offset estimation algorithms for Time Division Duplexing (TDD) OFDM systems, different timing metrics are proposed to determine the beginning of a burst or symbol. In this contribution we investigated the different timing metrics in order to establish their impact on the

  18. Analysis of emergency department waiting lines

    Directory of Open Access Journals (Sweden)

    Urška Močnik

    2014-10-01

    Full Text Available Background: Steady increase in the numbers of patients seeking medical assistance has recently been observed at the emergency department of the health center under study. This has led to increases in waiting times for patients. The management of the health center has been considering to implement certain measures to remedy this situation. One proposed solution is to add an additional physician to the emergency department. A computer model was constructed to simulate waiting lines and analyze the economic feasibility of employing an additional physician.Aim: This paper analyzes the waiting lines at the emergency department and performs an economic feasibility study to determine whether adding an additional physician to the department would be economically justified.Methods: Data about waiting times at the emergency department were collected to study the situation. For each patient, the arrival time at the waiting room and the starting and ending times of the examination were registered. The data were collected from 13 June 2011 to 25 September 2011. The sample included data on 65 nightly standbys, nine standbys on Saturdays, and 16 standbys on Sundays. Due to incomplete entries, data for nine weekly standbys and six Saturday standbys were excluded from the sample. Based on the data collected, we calculated the waiting and examination times per patient, average number of patients, average waiting time, average examination time, share of active standby teams in total standby time, and number of patients in different time periods. The study involved 1,039 patients. Using a synthesis method, we designed a computer model of waiting lines and economic feasibility. The model was validated using comparative analysis. A what-if analysis was performed using various computer simulations with various scenarios to consider the outcomes of decision alternatives. We applied economic analysis to select the best possible solution.Results: The research results

  19. A polynomial time algorithm for checking regularity of totally normed process algebra

    NARCIS (Netherlands)

    Yang, F.; Huang, H.

    2015-01-01

    A polynomial algorithm for the regularity problem of weak and branching bisimilarity on totally normed process algebra (PA) processes is given. Its time complexity is O(n 3 +mn) O(n3+mn), where n is the number of transition rules and m is the maximal length of the rules. The algorithm works for

  20. Genetic algorithms for adaptive real-time control in space systems

    Science.gov (United States)

    Vanderzijp, J.; Choudry, A.

    1988-01-01

    Genetic Algorithms that are used for learning as one way to control the combinational explosion associated with the generation of new rules are discussed. The Genetic Algorithm approach tends to work best when it can be applied to a domain independent knowledge representation. Applications to real time control in space systems are discussed.

  1. Formulations and exact algorithms for the vehicle routing problem with time windows

    DEFF Research Database (Denmark)

    Kallehauge, Brian

    2008-01-01

    In this paper we review the exact algorithms proposed in the last three decades for the solution of the vehicle routing problem with time windows (VRPTW). The exact algorithms for the VRPTW are in many aspects inherited from work on the traveling salesman problem (TSP). In recognition of this fact...

  2. Algorithm Development for a Real-Time Military Noise Monitor

    National Research Council Canada - National Science Library

    Vipperman, Jeffrey S; Bucci, Brian

    2006-01-01

    The long-range goal of this 1-year SERDP Exploratory Development (SEED) project was to create an improved real-time, high-energy military impulse noise monitoring system that can detect events with peak levels (Lpk...

  3. Two-pass imputation algorithm for missing value estimation in gene expression time series.

    Science.gov (United States)

    Tsiporkova, Elena; Boeva, Veselka

    2007-10-01

    Gene expression microarray experiments frequently generate datasets with multiple values missing. However, most of the analysis, mining, and classification methods for gene expression data require a complete matrix of gene array values. Therefore, the accurate estimation of missing values in such datasets has been recognized as an important issue, and several imputation algorithms have already been proposed to the biological community. Most of these approaches, however, are not particularly suitable for time series expression profiles. In view of this, we propose a novel imputation algorithm, which is specially suited for the estimation of missing values in gene expression time series data. The algorithm utilizes Dynamic Time Warping (DTW) distance in order to measure the similarity between time expression profiles, and subsequently selects for each gene expression profile with missing values a dedicated set of candidate profiles for estimation. Three different DTW-based imputation (DTWimpute) algorithms have been considered: position-wise, neighborhood-wise, and two-pass imputation. These have initially been prototyped in Perl, and their accuracy has been evaluated on yeast expression time series data using several different parameter settings. The experiments have shown that the two-pass algorithm consistently outperforms, in particular for datasets with a higher level of missing entries, the neighborhood-wise and the position-wise algorithms. The performance of the two-pass DTWimpute algorithm has further been benchmarked against the weighted K-Nearest Neighbors algorithm, which is widely used in the biological community; the former algorithm has appeared superior to the latter one. Motivated by these findings, indicating clearly the added value of the DTW techniques for missing value estimation in time series data, we have built an optimized C++ implementation of the two-pass DTWimpute algorithm. The software also provides for a choice between three different

  4. A sub-cubic time algorithm for computing the quartet distance between two general trees

    DEFF Research Database (Denmark)

    Nielsen, Jesper; Kristensen, Anders Kabell; Mailund, Thomas

    2011-01-01

    Background When inferring phylogenetic trees different algorithms may give different trees. To study such effects a measure for the distance between two trees is useful. Quartet distance is one such measure, and is the number of quartet topologies that differ between two trees. Results We have...... derived a new algorithm for computing the quartet distance between a pair of general trees, i.e. trees where inner nodes can have any degree ≥ 3. The time and space complexity of our algorithm is sub-cubic in the number of leaves and does not depend on the degree of the inner nodes. This makes...... it the fastest algorithm so far for computing the quartet distance between general trees independent of the degree of the inner nodes. Conclusions We have implemented our algorithm and two of the best competitors. Our new algorithm is significantly faster than the competition and seems to run in close...

  5. [Study of the labor market for dentists who recieved Norwegian authorization during 1972-1975. I. Waiting time and alternative employment before the 1st relevant job].

    Science.gov (United States)

    Haugejorden, O

    1977-07-01

    The purpose of the investigation was to monitor changes in the labour market situation for dentists who received authorization to practise dentistry in Norway during the years 1972-1975. Data was collected by postal questionnaire during April/May of the year following authorization, except for the 1972 cohort, which was contacted the second year after authorization. A 92-95 per cent response rate was achieved using one follow-up (Table 1). The percentage of respondents who waited 8 weeks or more to acquire a job in dentistry increased from 15 for those authorized in 1972 to 36 for the 1975 group (Table 3). The proportion of dentists who took paid employment other than dentistry, increased from just over 3 per cent for the 1973 to 14 per cent for the 1975 cohort (Table 4). This development has occured despite a decrease in the number of dentists receiving authorization each year and has resulted in a limited emigration of dentists. It is suggested that the favourable supply of dentists in relation to existing demand for dental services presents an ideal opportunity for attempting to solve dental health problems which have received inadequate attention in the past.

  6. Real-time slicing algorithm for Stereolithography (STL) CAD model applied in additive manufacturing industry

    Science.gov (United States)

    Adnan, F. A.; Romlay, F. R. M.; Shafiq, M.

    2018-04-01

    Owing to the advent of the industrial revolution 4.0, the need for further evaluating processes applied in the additive manufacturing application particularly the computational process for slicing is non-trivial. This paper evaluates a real-time slicing algorithm for slicing an STL formatted computer-aided design (CAD). A line-plane intersection equation was applied to perform the slicing procedure at any given height. The application of this algorithm has found to provide a better computational time regardless the number of facet in the STL model. The performance of this algorithm is evaluated by comparing the results of the computational time for different geometry.

  7. Strategy as active waiting.

    Science.gov (United States)

    Sull, Donald N

    2005-09-01

    Successful executives who cut their teeth in stable industries or in developed countries often stumble when they face more volatile markets. They falter, in part, because they assume they can gaze deep into the future and develop a long-term strategy that will confer a sustainable competitive advantage. But visibility into the future of volatile markets is sharply limited because so many different variables are in play. Factors such as technological innovation, customers' evolving needs, government policy, and changes in the capital markets interact with one another to create unexpected outcomes. Over the past six years, Donald Sull, an associate professor at London Business School, has led a research project examining some of the world's most volatile markets, from national markets like China and Brazil to industries like enterprise software, telecommunications, and airlines. One of the most striking findings from this research is the importance of taking action during comparative lulls in the storm. Huge business opportunities are relatively rare; they come along only once or twice in a decade. And, for the most part, companies can't manufacture those opportunities; changes in the external environment converge to make them happen. What managers can do is prepare for these golden opportunities by managing smart during the comparative calm of business as usual. During these periods of active waiting, leaders must probe the future and remain alert to anomalies that signal potential threats or opportunities; exercise restraint to preserve their war chests; and maintain discipline to keep the troops battle ready. When a golden opportunity or"sudden death"threat emerges, managers must have the courage to declare the main effort and concentrate resources to seize the moment.

  8. Performances of the New Real Time Tsunami Detection Algorithm applied to tide gauges data

    Science.gov (United States)

    Chierici, F.; Embriaco, D.; Morucci, S.

    2017-12-01

    Real-time tsunami detection algorithms play a key role in any Tsunami Early Warning System. We have developed a new algorithm for tsunami detection (TDA) based on the real-time tide removal and real-time band-pass filtering of seabed pressure time series acquired by Bottom Pressure Recorders. The TDA algorithm greatly increases the tsunami detection probability, shortens the detection delay and enhances detection reliability with respect to the most widely used tsunami detection algorithm, while containing the computational cost. The algorithm is designed to be used also in autonomous early warning systems with a set of input parameters and procedures which can be reconfigured in real time. We have also developed a methodology based on Monte Carlo simulations to test the tsunami detection algorithms. The algorithm performance is estimated by defining and evaluating statistical parameters, namely the detection probability, the detection delay, which are functions of the tsunami amplitude and wavelength, and the occurring rate of false alarms. In this work we present the performance of the TDA algorithm applied to tide gauge data. We have adapted the new tsunami detection algorithm and the Monte Carlo test methodology to tide gauges. Sea level data acquired by coastal tide gauges in different locations and environmental conditions have been used in order to consider real working scenarios in the test. We also present an application of the algorithm to the tsunami event generated by Tohoku earthquake on March 11th 2011, using data recorded by several tide gauges scattered all over the Pacific area.

  9. Hardware Algorithms For Tile-Based Real-Time Rendering

    NARCIS (Netherlands)

    Crisu, D.

    2012-01-01

    In this dissertation, we present the GRAphics AcceLerator (GRAAL) framework for developing embedded tile-based rasterization hardware for mobile devices, meant to accelerate real-time 3-D graphics (OpenGL compliant) applications. The goal of the framework is a low-cost, low-power, high-performance

  10. Outlier detection algorithms for least squares time series regression

    DEFF Research Database (Denmark)

    Johansen, Søren; Nielsen, Bent

    We review recent asymptotic results on some robust methods for multiple regression. The regressors include stationary and non-stationary time series as well as polynomial terms. The methods include the Huber-skip M-estimator, 1-step Huber-skip M-estimators, in particular the Impulse Indicator Sat...

  11. An algorithm for learning real-time automata (extended abstract)

    NARCIS (Netherlands)

    Verwer, S.E.; De Weerdt, M.M.; Witteveen, C.

    2007-01-01

    A common model for discrete event systems is a deterministic finite automaton (DFA). An advantage of this model is that it can be interpreted by domain experts. When observing a real-world system, however, there often is more information than just the sequence of discrete events: the time at which

  12. Improving real-time train dispatching : Models, algorithms and applications

    NARCIS (Netherlands)

    D'Ariano, A.

    2008-01-01

    Traffic controllers monitor railway traffic sequencing train movements and setting routes with the aim of ensuring smooth train behaviour and limiting as much as existing delays. Due to the strict time limit available for computing a new timetable during operations, which so far is rather infeasible

  13. Algorithmic power management - Energy minimisation under real-time constraints

    NARCIS (Netherlands)

    Gerards, Marco Egbertus Theodorus

    2014-01-01

    Energy consumption is a major concern for designers of embedded devices. Especially for battery operated systems (like many embedded systems), the energy consumption limits the time for which a device can be active, and the amount of processing that can take place. In this thesis we study how the

  14. Algorithmic power management: energy minimisation under real-time constraints

    NARCIS (Netherlands)

    Gerards, Marco Egbertus Theodorus

    2014-01-01

    Energy consumption is a major concern for designers of embedded devices. Especially for battery operated systems (like many embedded systems), the energy consumption limits the time for which a device can be active, and the amount of processing that can take place. In this thesis we study how the

  15. Approximation algorithms for replenishment problems with fixed turnover times

    NARCIS (Netherlands)

    T. Bosman (Thomas); M. van Ee (Martijn); Y. Jiao (Yang); A. Marchetti Spaccamela (Alberto); R. Ravi; L. Stougie (Leen)

    2018-01-01

    textabstractWe introduce and study a class of optimization problems we coin replenishment problems with fixed turnover times: a very natural model that has received little attention in the literature. Nodes with capacity for storing a certain commodity are located at various places; at each node the

  16. Implicit time-dependent finite different algorithm for quench simulation

    International Nuclear Information System (INIS)

    Koizumi, Norikiyo; Takahashi, Yoshikazu; Tsuji, Hiroshi

    1994-12-01

    A magnet in a fusion machine has many difficulties in its application because of requirement of a large operating current, high operating field and high breakdown voltage. A cable-in-conduit (CIC) conductor is the best candidate to overcome these difficulties. However, there remained uncertainty in a quench event in the cable-in-conduit conductor because of a difficulty to analyze a fluid dynamics equation. Several scientists, then, developed the numerical code for the quench simulation. However, most of them were based on an explicit time-dependent finite difference scheme. In this scheme, a discrete time increment is strictly restricted by CFL (Courant-Friedrichs-Lewy) condition. Therefore, long CPU time was consumed for the quench simulation. Authors, then, developed a new quench simulation code, POCHI1, which is based on an implicit time dependent scheme. In POCHI1, the fluid dynamics equation is linearlized according to a procedure applied by Beam and Warming and then, a tridiagonal system can be offered. Therefore, no iteration is necessary to solve the fluid dynamics equation. This leads great reduction of the CPU time. Also, POCHI1 can cope with non-linear boundary condition. In this study, comparison with experimental results was carried out. The normal zone propagation behavior was investigated in two samples of CIC conductors which had different hydraulic diameters. The measured and simulated normal zone propagation length showed relatively good agreement. However, the behavior of the normal voltage shows a little disagreement. These results indicate necessity to improve the treatment of the heat transfer coefficient in the turbulent flow region and the electric resistivity of the copper stabilizer in high temperature and high field region. (author)

  17. Adaptive modification of the delayed feedback control algorithm with a continuously varying time delay

    International Nuclear Information System (INIS)

    Pyragas, V.; Pyragas, K.

    2011-01-01

    We propose a simple adaptive delayed feedback control algorithm for stabilization of unstable periodic orbits with unknown periods. The state dependent time delay is varied continuously towards the period of controlled orbit according to a gradient-descent method realized through three simple ordinary differential equations. We demonstrate the efficiency of the algorithm with the Roessler and Mackey-Glass chaotic systems. The stability of the controlled orbits is proven by computation of the Lyapunov exponents of linearized equations. -- Highlights: → A simple adaptive modification of the delayed feedback control algorithm is proposed. → It enables the control of unstable periodic orbits with unknown periods. → The delay time is varied continuously according to a gradient descend method. → The algorithm is embodied by three simple ordinary differential equations. → The validity of the algorithm is proven by computation of the Lyapunov exponents.

  18. An Improved Phase Gradient Autofocus Algorithm Used in Real-time Processing

    Directory of Open Access Journals (Sweden)

    Qing Ji-ming

    2015-10-01

    Full Text Available The Phase Gradient Autofocus (PGA algorithm can remove the high order phase error effectively, which is of great significance to get high resolution images in real-time processing. While PGA usually needs iteration, which necessitates long working hours. In addition, the performances of the algorithm are not stable in different scene applications. This severely constrains the application of PGA in real-time processing. Isolated scatter selection and windowing are two important algorithmic steps of Phase Gradient Autofocus Algorithm. Therefore, this paper presents an isolated scatter selection method based on sample mean and a windowing method based on pulse envelope. These two methods are highly adaptable to data, which would make the algorithm obtain better stability and need less iteration. The adaptability of the improved PGA is demonstrated with the experimental results of real radar data.

  19. Real time implementation of the parametric imaging correlation algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Bogorodski, Piotr; Wolek, Tomasz; Wasielewski, Jaroslaw; Piatkowski, Adam [Medical and Nuclear Electronics Division, Institute of Radioelectronics, Warsaw University of Technology, 00-665 Warsaw, Nowowiejska 15/19 (Poland)

    1999-12-31

    A novel method for functional image evaluation from image set obtained in contrast aided Ultrafast Computed Tomography and Magnetic Resonance Imaging will be presented. The method converts temporal set of images of first-pass transit of injected contrast, to a single parametric image. The main difference between proposed procedure and other widely accepted methods is fast, that our method applies correlation and discrimination analysis to each concentration-time curve, instead of fitting them to the given a priori tracer kinetics model. A stress will be put on execution speed (i.e. shortening of the time required to obtain a perfusion relevant image), and easiest user interface allowing the physician to utilize the system without any technical assistance. Both execution speed and user interface should satisfy requirements in the interventional procedures. (authors)

  20. Parallel algorithms for simulating continuous time Markov chains

    Science.gov (United States)

    Nicol, David M.; Heidelberger, Philip

    1992-01-01

    We have previously shown that the mathematical technique of uniformization can serve as the basis of synchronization for the parallel simulation of continuous-time Markov chains. This paper reviews the basic method and compares five different methods based on uniformization, evaluating their strengths and weaknesses as a function of problem characteristics. The methods vary in their use of optimism, logical aggregation, communication management, and adaptivity. Performance evaluation is conducted on the Intel Touchstone Delta multiprocessor, using up to 256 processors.

  1. False-nearest-neighbors algorithm and noise-corrupted time series

    International Nuclear Information System (INIS)

    Rhodes, C.; Morari, M.

    1997-01-01

    The false-nearest-neighbors (FNN) algorithm was originally developed to determine the embedding dimension for autonomous time series. For noise-free computer-generated time series, the algorithm does a good job in predicting the embedding dimension. However, the problem of predicting the embedding dimension when the time-series data are corrupted by noise was not fully examined in the original studies of the FNN algorithm. Here it is shown that with large data sets, even small amounts of noise can lead to incorrect prediction of the embedding dimension. Surprisingly, as the length of the time series analyzed by FNN grows larger, the cause of incorrect prediction becomes more pronounced. An analysis of the effect of noise on the FNN algorithm and a solution for dealing with the effects of noise are given here. Some results on the theoretically correct choice of the FNN threshold are also presented. copyright 1997 The American Physical Society

  2. Computing Fault-Containment Times of Self-Stabilizing Algorithms Using Lumped Markov Chains

    Directory of Open Access Journals (Sweden)

    Volker Turau

    2018-05-01

    Full Text Available The analysis of self-stabilizing algorithms is often limited to the worst case stabilization time starting from an arbitrary state, i.e., a state resulting from a sequence of faults. Considering the fact that these algorithms are intended to provide fault tolerance in the long run, this is not the most relevant metric. A common situation is that a running system is an a legitimate state when hit by a single fault. This event has a much higher probability than multiple concurrent faults. Therefore, the worst case time to recover from a single fault is more relevant than the recovery time from a large number of faults. This paper presents techniques to derive upper bounds for the mean time to recover from a single fault for self-stabilizing algorithms based on Markov chains in combination with lumping. To illustrate the applicability of the techniques they are applied to a new self-stabilizing coloring algorithm.

  3. A Scalable GVT Estimation Algorithm for PDES: Using Lower Bound of Event-Bulk-Time

    Directory of Open Access Journals (Sweden)

    Yong Peng

    2015-01-01

    Full Text Available Global Virtual Time computation of Parallel Discrete Event Simulation is crucial for conducting fossil collection and detecting the termination of simulation. The triggering condition of GVT computation in typical approaches is generally based on the wall-clock time or logical time intervals. However, the GVT value depends on the timestamps of events rather than the wall-clock time or logical time intervals. Therefore, it is difficult for the existing approaches to select appropriate time intervals to compute the GVT value. In this study, we propose a scalable GVT estimation algorithm based on Lower Bound of Event-Bulk-Time, which triggers the computation of the GVT value according to the number of processed events. In order to calculate the number of transient messages, our algorithm employs Event-Bulk to record the messages sent and received by Logical Processes. To eliminate the performance bottleneck, we adopt an overlapping computation approach to distribute the workload of GVT computation to all worker-threads. We compare our algorithm with the fast asynchronous GVT algorithm using PHOLD benchmark on the shared memory machine. Experimental results indicate that our algorithm has a light overhead and shows higher speedup and accuracy of GVT computation than the fast asynchronous GVT algorithm.

  4. Implementation of Tree and Butterfly Barriers with Optimistic Time Management Algorithms for Discrete Event Simulation

    Science.gov (United States)

    Rizvi, Syed S.; Shah, Dipali; Riasat, Aasia

    The Time Wrap algorithm [3] offers a run time recovery mechanism that deals with the causality errors. These run time recovery mechanisms consists of rollback, anti-message, and Global Virtual Time (GVT) techniques. For rollback, there is a need to compute GVT which is used in discrete-event simulation to reclaim the memory, commit the output, detect the termination, and handle the errors. However, the computation of GVT requires dealing with transient message problem and the simultaneous reporting problem. These problems can be dealt in an efficient manner by the Samadi's algorithm [8] which works fine in the presence of causality errors. However, the performance of both Time Wrap and Samadi's algorithms depends on the latency involve in GVT computation. Both algorithms give poor latency for large simulation systems especially in the presence of causality errors. To improve the latency and reduce the processor ideal time, we implement tree and butterflies barriers with the optimistic algorithm. Our analysis shows that the use of synchronous barriers such as tree and butterfly with the optimistic algorithm not only minimizes the GVT latency but also minimizes the processor idle time.

  5. Development of real-time plasma analysis and control algorithms for the TCV tokamak using SIMULINK

    International Nuclear Information System (INIS)

    Felici, F.; Le, H.B.; Paley, J.I.; Duval, B.P.; Coda, S.; Moret, J.-M.; Bortolon, A.; Federspiel, L.; Goodman, T.P.; Hommen, G.; Karpushov, A.; Piras, F.; Pitzschke, A.; Romero, J.; Sevillano, G.; Sauter, O.; Vijvers, W.

    2014-01-01

    Highlights: • A new digital control system for the TCV tokamak has been commissioned. • The system is entirely programmable by SIMULINK, allowing rapid algorithm development. • Different control system nodes can run different algorithms at varying sampling times. • The previous control system functions have been emulated and improved. • New capabilities include MHD control, profile control, equilibrium reconstruction. - Abstract: One of the key features of the new digital plasma control system installed on the TCV tokamak is the possibility to rapidly design, test and deploy real-time algorithms. With this flexibility the new control system has been used for a large number of new experiments which exploit TCV's powerful actuators consisting of 16 individually controllable poloidal field coils and 7 real-time steerable electron cyclotron (EC) launchers. The system has been used for various applications, ranging from event-based real-time MHD control to real-time current diffusion simulations. These advances have propelled real-time control to one of the cornerstones of the TCV experimental program. Use of the SIMULINK graphical programming language to directly program the control system has greatly facilitated algorithm development and allowed a multitude of different algorithms to be deployed in a short time. This paper will give an overview of the developed algorithms and their application in physics experiments

  6. RB Particle Filter Time Synchronization Algorithm Based on the DPM Model.

    Science.gov (United States)

    Guo, Chunsheng; Shen, Jia; Sun, Yao; Ying, Na

    2015-09-03

    Time synchronization is essential for node localization, target tracking, data fusion, and various other Wireless Sensor Network (WSN) applications. To improve the estimation accuracy of continuous clock offset and skew of mobile nodes in WSNs, we propose a novel time synchronization algorithm, the Rao-Blackwellised (RB) particle filter time synchronization algorithm based on the Dirichlet process mixture (DPM) model. In a state-space equation with a linear substructure, state variables are divided into linear and non-linear variables by the RB particle filter algorithm. These two variables can be estimated using Kalman filter and particle filter, respectively, which improves the computational efficiency more so than if only the particle filter was used. In addition, the DPM model is used to describe the distribution of non-deterministic delays and to automatically adjust the number of Gaussian mixture model components based on the observational data. This improves the estimation accuracy of clock offset and skew, which allows achieving the time synchronization. The time synchronization performance of this algorithm is also validated by computer simulations and experimental measurements. The results show that the proposed algorithm has a higher time synchronization precision than traditional time synchronization algorithms.

  7. Performance Evaluation of New Joint EDF-RM Scheduling Algorithm for Real Time Distributed System

    Directory of Open Access Journals (Sweden)

    Rashmi Sharma

    2014-01-01

    Full Text Available In Real Time System, the achievement of deadline is the main target of every scheduling algorithm. Earliest Deadline First (EDF, Rate Monotonic (RM, and least Laxity First are some renowned algorithms that work well in their own context. As we know, there is a very common problem Domino's effect in EDF that is generated due to overloading condition (EDF is not working well in overloading situation. Similarly, performance of RM is degraded in underloading condition. We can say that both algorithms are complements of each other. Deadline missing in both events happens because of their utilization bounding strategy. Therefore, in this paper we are proposing a new scheduling algorithm that carries through the drawback of both existing algorithms. Joint EDF-RM scheduling algorithm is implemented in global scheduler that permits task migration mechanism in between processors in the system. In order to check the improved behavior of proposed algorithm we perform simulation. Results are achieved and evaluated in terms of Success Ratio (SR, Average CPU Utilization (ECU, Failure Ratio (FR, and Maximum Tardiness parameters. In the end, the results are compared with the existing (EDF, RM, and D_R_EDF algorithms. It has been shown that the proposed algorithm performs better during overloading condition as well in underloading condition.

  8. How Tolerable is Delay? Consumers' Evaluations of Internet Web Sites After Waiting

    NARCIS (Netherlands)

    Dellaert, B.G.C.; Kahn, B.

    1998-01-01

    How consumers’ waiting times affect their retrospective evaluations of Internet Web Sites is investigated in four computer-based experiments. Results show that waiting can but does not always negatively affect evaluations of Web Sites. Results also show that the potential negative effects of waiting

  9. Efficient Geo-Computational Algorithms for Constructing Space-Time Prisms in Road Networks

    Directory of Open Access Journals (Sweden)

    Hui-Ping Chen

    2016-11-01

    Full Text Available The Space-time prism (STP is a key concept in time geography for analyzing human activity-travel behavior under various Space-time constraints. Most existing time-geographic studies use a straightforward algorithm to construct STPs in road networks by using two one-to-all shortest path searches. However, this straightforward algorithm can introduce considerable computational overhead, given the fact that accessible links in a STP are generally a small portion of the whole network. To address this issue, an efficient geo-computational algorithm, called NTP-A*, is proposed. The proposed NTP-A* algorithm employs the A* and branch-and-bound techniques to discard inaccessible links during two shortest path searches, and thereby improves the STP construction performance. Comprehensive computational experiments are carried out to demonstrate the computational advantage of the proposed algorithm. Several implementation techniques, including the label-correcting technique and the hybrid link-node labeling technique, are discussed and analyzed. Experimental results show that the proposed NTP-A* algorithm can significantly improve STP construction performance in large-scale road networks by a factor of 100, compared with existing algorithms.

  10. A polynomial time algorithm for solving the maximum flow problem in directed networks

    International Nuclear Information System (INIS)

    Tlas, M.

    2015-01-01

    An efficient polynomial time algorithm for solving maximum flow problems has been proposed in this paper. The algorithm is basically based on the binary representation of capacities; it solves the maximum flow problem as a sequence of O(m) shortest path problems on residual networks with nodes and m arcs. It runs in O(m"2r) time, where is the smallest integer greater than or equal to log B , and B is the largest arc capacity of the network. A numerical example has been illustrated using this proposed algorithm.(author)

  11. Real time algorithm temperature compensation in tunable laser / VCSEL based WDM-PON system

    DEFF Research Database (Denmark)

    Iglesias Olmedo, Miguel; Rodes Lopez, Roberto; Pham, Tien Thang

    2012-01-01

    We report on a real time experimental validation of a centralized algorithm for temperature compensation of tunable laser/VCSEL at ONU and OLT, respectively. Locking to a chosen WDM channel is shown for temperature changes over 40°C.......We report on a real time experimental validation of a centralized algorithm for temperature compensation of tunable laser/VCSEL at ONU and OLT, respectively. Locking to a chosen WDM channel is shown for temperature changes over 40°C....

  12. CAT-PUMA: CME Arrival Time Prediction Using Machine learning Algorithms

    Science.gov (United States)

    Liu, Jiajia; Ye, Yudong; Shen, Chenglong; Wang, Yuming; Erdélyi, Robert

    2018-04-01

    CAT-PUMA (CME Arrival Time Prediction Using Machine learning Algorithms) quickly and accurately predicts the arrival of Coronal Mass Ejections (CMEs) of CME arrival time. The software was trained via detailed analysis of CME features and solar wind parameters using 182 previously observed geo-effective partial-/full-halo CMEs and uses algorithms of the Support Vector Machine (SVM) to make its predictions, which can be made within minutes of providing the necessary input parameters of a CME.

  13. Implementing the access and waiting time standard for early intervention in psychosis in the United Kingdom: An evaluation of referrals and post-assessment outcomes over the first year of operation.

    Science.gov (United States)

    Adamson, Vidyah; Barrass, Emma; McConville, Stephen; Irikok, Chantelle; Taylor, Kim; Pitt, Steve; Van Duyn, Rob; Bennett, Susan; Jackson, Lisa; Carroll, Jon; Andrews, Mark; Parker, Ann; Wright, Caroline; Greathead, Katie; Price, David

    2018-03-26

    Improving timely access to evidence-based treatment for people aged 14-65 years experiencing a first episode psychosis (FEP) or an at-risk mental state (ARMS) for psychosis is a national priority within the United Kingdom. An early intervention in psychosis (EIP) access and waiting time standard has been set which has extended the age range and acceptance criteria for services. This descriptive evaluation reports upon the referrals and access to treatment times within an EIP service over the first year of operating in line with the access and waiting time standard. Patient pathways and post-assessment status are also described. The service received 406 referrals, of which 88% (n = 357) were assessed. The mean length of time to treatment was 1.5 weeks, with 88% being seen within 2 weeks. Of those who engaged in an assessment, 34% (n = 138) were identified as ARMS cases and 30% (n = 123) were identified as FEP. Over 35 year olds accounted for 22% (n = 80) of the total accepted cases. The findings indicate clinical and operational issues, which will need careful consideration in the future planning of services. The high number of ARMS cases highlights the importance of clear treatment pathways and targeted interventions and may suggest a need to commission distinct ARMS services. The number of people who met the extended age and service acceptance criteria may suggest a need to adapt or redesign clinical services to meet the age-specific needs of over 35 year olds and those with an ARMS. It is unclear how changes to the remit of EIP services will impact upon future clinical outcomes. © 2018 John Wiley & Sons Australia, Ltd.

  14. A Gaussian Process Based Online Change Detection Algorithm for Monitoring Periodic Time Series

    Energy Technology Data Exchange (ETDEWEB)

    Chandola, Varun [ORNL; Vatsavai, Raju [ORNL

    2011-01-01

    Online time series change detection is a critical component of many monitoring systems, such as space and air-borne remote sensing instruments, cardiac monitors, and network traffic profilers, which continuously analyze observations recorded by sensors. Data collected by such sensors typically has a periodic (seasonal) component. Most existing time series change detection methods are not directly applicable to handle such data, either because they are not designed to handle periodic time series or because they cannot operate in an online mode. We propose an online change detection algorithm which can handle periodic time series. The algorithm uses a Gaussian process based non-parametric time series prediction model and monitors the difference between the predictions and actual observations within a statistically principled control chart framework to identify changes. A key challenge in using Gaussian process in an online mode is the need to solve a large system of equations involving the associated covariance matrix which grows with every time step. The proposed algorithm exploits the special structure of the covariance matrix and can analyze a time series of length T in O(T^2) time while maintaining a O(T) memory footprint, compared to O(T^4) time and O(T^2) memory requirement of standard matrix manipulation methods. We experimentally demonstrate the superiority of the proposed algorithm over several existing time series change detection algorithms on a set of synthetic and real time series. Finally, we illustrate the effectiveness of the proposed algorithm for identifying land use land cover changes using Normalized Difference Vegetation Index (NDVI) data collected for an agricultural region in Iowa state, USA. Our algorithm is able to detect different types of changes in a NDVI validation data set (with ~80% accuracy) which occur due to crop type changes as well as disruptive changes (e.g., natural disasters).

  15. Pyramid Algorithm Framework for Real-Time Image Effects

    DEFF Research Database (Denmark)

    Sangüesa, Adriá Arbués; Ene, Andreea-Daniela; Jørgensen, Nicolai Krogh

    2016-01-01

    Pyramid methods are useful for certain image processing techniques due to their linear time complexity. Implementing them using compute shaders provides a basis for rendering image effects with reduced impact on performance compared to conventional methods. Although pyramid methods are used...... in the game industry, they are not easily accessible to all developers because many game engines do not include built-in support. We present a framework for a popular game engine that allows users to take advantage of pyramid methods for developing image effects. In order to evaluate the performance...... and to demonstrate the framework, a few image effects were implemented. These effects were compared to built-in effects of the same game engine. The results showed that the built-in image effects performed slightly better. The performance of our framework could potentially be improved through optimisation, mainly...

  16. PRESEE: an MDL/MML algorithm to time-series stream segmenting.

    Science.gov (United States)

    Xu, Kaikuo; Jiang, Yexi; Tang, Mingjie; Yuan, Changan; Tang, Changjie

    2013-01-01

    Time-series stream is one of the most common data types in data mining field. It is prevalent in fields such as stock market, ecology, and medical care. Segmentation is a key step to accelerate the processing speed of time-series stream mining. Previous algorithms for segmenting mainly focused on the issue of ameliorating precision instead of paying much attention to the efficiency. Moreover, the performance of these algorithms depends heavily on parameters, which are hard for the users to set. In this paper, we propose PRESEE (parameter-free, real-time, and scalable time-series stream segmenting algorithm), which greatly improves the efficiency of time-series stream segmenting. PRESEE is based on both MDL (minimum description length) and MML (minimum message length) methods, which could segment the data automatically. To evaluate the performance of PRESEE, we conduct several experiments on time-series streams of different types and compare it with the state-of-art algorithm. The empirical results show that PRESEE is very efficient for real-time stream datasets by improving segmenting speed nearly ten times. The novelty of this algorithm is further demonstrated by the application of PRESEE in segmenting real-time stream datasets from ChinaFLUX sensor networks data stream.

  17. Mode Identification of Guided Ultrasonic Wave using Time- Frequency Algorithm

    International Nuclear Information System (INIS)

    Yoon, Byung Sik; Yang, Seung Han; Cho, Yong Sang; Kim, Yong Sik; Lee, Hee Jong

    2007-01-01

    The ultrasonic guided waves are waves whose propagation characteristics depend on structural thickness and shape such as those in plates, tubes, rods, and embedded layers. If the angle of incidence or the frequency of sound is adjusted properly, the reflected and refracted energy within the structure will constructively interfere, thereby launching the guided wave. Because these waves penetrate the entire thickness of the tube and propagate parallel to the surface, a large portion of the material can be examined from a single transducer location. The guided ultrasonic wave has various merits like above. But various kind of modes are propagating through the entire thickness, so we don't know the which mode is received. Most of applications are limited from mode selection and mode identification. So the mode identification is very important process for guided ultrasonic inspection application. In this study, various time-frequency analysis methodologies are developed and compared for mode identification tool of guided ultrasonic signal. For this study, a high power tone-burst ultrasonic system set up for the generation and receive of guided waves. And artificial notches were fabricated on the Aluminum plate for the experiment on the mode identification

  18. Night-Time Vehicle Detection Algorithm Based on Visual Saliency and Deep Learning

    Directory of Open Access Journals (Sweden)

    Yingfeng Cai

    2016-01-01

    Full Text Available Night vision systems get more and more attention in the field of automotive active safety field. In this area, a number of researchers have proposed far-infrared sensor based night-time vehicle detection algorithm. However, existing algorithms have low performance in some indicators such as the detection rate and processing time. To solve this problem, we propose a far-infrared image vehicle detection algorithm based on visual saliency and deep learning. Firstly, most of the nonvehicle pixels will be removed with visual saliency computation. Then, vehicle candidate will be generated by using prior information such as camera parameters and vehicle size. Finally, classifier trained with deep belief networks will be applied to verify the candidates generated in last step. The proposed algorithm is tested in around 6000 images and achieves detection rate of 92.3% and processing time of 25 Hz which is better than existing methods.

  19. Energy-Aware Real-Time Task Scheduling for Heterogeneous Multiprocessors with Particle Swarm Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    Weizhe Zhang

    2014-01-01

    Full Text Available Energy consumption in computer systems has become a more and more important issue. High energy consumption has already damaged the environment to some extent, especially in heterogeneous multiprocessors. In this paper, we first formulate and describe the energy-aware real-time task scheduling problem in heterogeneous multiprocessors. Then we propose a particle swarm optimization (PSO based algorithm, which can successfully reduce the energy cost and the time for searching feasible solutions. Experimental results show that the PSO-based energy-aware metaheuristic uses 40%–50% less energy than the GA-based and SFLA-based algorithms and spends 10% less time than the SFLA-based algorithm in finding the solutions. Besides, it can also find 19% more feasible solutions than the SFLA-based algorithm.

  20. An efficient genetic algorithm for a hybrid flow shop scheduling problem with time lags and sequence-dependent setup time

    Directory of Open Access Journals (Sweden)

    Farahmand-Mehr Mohammad

    2014-01-01

    Full Text Available In this paper, a hybrid flow shop scheduling problem with a new approach considering time lags and sequence-dependent setup time in realistic situations is presented. Since few works have been implemented in this field, the necessity of finding better solutions is a motivation to extend heuristic or meta-heuristic algorithms. This type of production system is found in industries such as food processing, chemical, textile, metallurgical, printed circuit board, and automobile manufacturing. A mixed integer linear programming (MILP model is proposed to minimize the makespan. Since this problem is known as NP-Hard class, a meta-heuristic algorithm, named Genetic Algorithm (GA, and three heuristic algorithms (Johnson, SPTCH and Palmer are proposed. Numerical experiments of different sizes are implemented to evaluate the performance of presented mathematical programming model and the designed GA in compare to heuristic algorithms and a benchmark algorithm. Computational results indicate that the designed GA can produce near optimal solutions in a short computational time for different size problems.

  1. Real-Time Algorithm for Relative Position Estimation Between Person and Robot Using a Monocular Camera

    International Nuclear Information System (INIS)

    Lee, Jung Uk; Sun, Ju Young; Won, Mooncheol

    2013-01-01

    In this paper, we propose a real-time algorithm for estimating the relative position of a person with respect to a robot (camera) using a monocular camera. The algorithm detects the head and shoulder regions of a person using HOG (Histogram of Oriented Gradient) feature vectors and an SVM (Support Vector Machine) classifier. The size and location of the detected area are used for calculating the relative distance and angle between the person and the camera on a robot. To increase the speed of the algorithm, we use a GPU and NVIDIA's CUDA library; the resulting algorithm speed is ∼ 15 Hz. The accuracy of the algorithm is compared with the output of a SICK laser scanner

  2. A Real-Time Reaction Obstacle Avoidance Algorithm for Autonomous Underwater Vehicles in Unknown Environments.

    Science.gov (United States)

    Yan, Zheping; Li, Jiyun; Zhang, Gengshi; Wu, Yi

    2018-02-02

    A novel real-time reaction obstacle avoidance algorithm (RRA) is proposed for autonomous underwater vehicles (AUVs) that must adapt to unknown complex terrains, based on forward looking sonar (FLS). To accomplish this algorithm, obstacle avoidance rules are planned, and the RRA processes are split into five steps Introduction only lists 4 so AUVs can rapidly respond to various environment obstacles. The largest polar angle algorithm (LPAA) is designed to change detected obstacle's irregular outline into a convex polygon, which simplifies the obstacle avoidance process. A solution is designed to solve the trapping problem existing in U-shape obstacle avoidance by an outline memory algorithm. Finally, simulations in three unknown obstacle scenes are carried out to demonstrate the performance of this algorithm, where the obtained obstacle avoidance trajectories are safety, smooth and near-optimal.

  3. Real-time recursive hyperspectral sample and band processing algorithm architecture and implementation

    CERN Document Server

    Chang, Chein-I

    2017-01-01

    This book explores recursive architectures in designing progressive hyperspectral imaging algorithms. In particular, it makes progressive imaging algorithms recursive by introducing the concept of Kalman filtering in algorithm design so that hyperspectral imagery can be processed not only progressively sample by sample or band by band but also recursively via recursive equations. This book can be considered a companion book of author’s books, Real-Time Progressive Hyperspectral Image Processing, published by Springer in 2016. Explores recursive structures in algorithm architecture Implements algorithmic recursive architecture in conjunction with progressive sample and band processing Derives Recursive Hyperspectral Sample Processing (RHSP) techniques according to Band-Interleaved Sample/Pixel (BIS/BIP) acquisition format Develops Recursive Hyperspectral Band Processing (RHBP) techniques according to Band SeQuential (BSQ) acquisition format for hyperspectral data.

  4. Real-Time Algorithm for Relative Position Estimation Between Person and Robot Using a Monocular Camera

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung Uk [Samsung Electroics, Suwon (Korea, Republic of); Sun, Ju Young; Won, Mooncheol [Chungnam Nat' l Univ., Daejeon (Korea, Republic of)

    2013-12-15

    In this paper, we propose a real-time algorithm for estimating the relative position of a person with respect to a robot (camera) using a monocular camera. The algorithm detects the head and shoulder regions of a person using HOG (Histogram of Oriented Gradient) feature vectors and an SVM (Support Vector Machine) classifier. The size and location of the detected area are used for calculating the relative distance and angle between the person and the camera on a robot. To increase the speed of the algorithm, we use a GPU and NVIDIA's CUDA library; the resulting algorithm speed is ∼ 15 Hz. The accuracy of the algorithm is compared with the output of a SICK laser scanner.

  5. Exponential-Time Algorithms and Complexity of NP-Hard Graph Problems

    DEFF Research Database (Denmark)

    Taslaman, Nina Sofia

    of algorithms, as well as investigations into how far such improvements can get under reasonable assumptions.      The first part is concerned with detection of cycles in graphs, especially parameterized generalizations of Hamiltonian cycles. A remarkably simple Monte Carlo algorithm is presented......NP-hard problems are deemed highly unlikely to be solvable in polynomial time. Still, one can often find algorithms that are substantially faster than brute force solutions. This thesis concerns such algorithms for problems from graph theory; techniques for constructing and improving this type......, and with high probability any found solution is shortest possible. Moreover, the algorithm can be used to find a cycle of given parity through the specified elements.      The second part concerns the hardness of problems encoded as evaluations of the Tutte polynomial at some fixed point in the rational plane...

  6. Evaluation of focused ultrasound algorithms: Issues for reducing pre-focal heating and treatment time.

    Science.gov (United States)

    Yiannakou, Marinos; Trimikliniotis, Michael; Yiallouras, Christos; Damianou, Christakis

    2016-02-01

    Due to the heating in the pre-focal field the delay between successive movements in high intensity focused ultrasound (HIFU) are sometimes as long as 60s, resulting to treatment time in the order of 2-3h. Because there is generally a requirement to reduce treatment time, we were motivated to explore alternative transducer motion algorithms in order to reduce pre-focal heating and treatment time. A 1 MHz single element transducer with 4 cm diameter and 10 cm focal length was used. A simulation model was developed that estimates the temperature, thermal dose and lesion development in the pre-focal field. The simulated temperature history that was combined with the motion algorithms produced thermal maps in the pre-focal region. Polyacrylimde gel phantom was used to evaluate the induced pre-focal heating for each motion algorithm used, and also was used to assess the accuracy of the simulation model. Three out of the six algorithms having successive steps close to each other, exhibited severe heating in the pre-focal field. Minimal heating was produced with the algorithms having successive steps apart from each other (square, square spiral and random). The last three algorithms were improved further (with small cost in time), thus eliminating completely the pre-focal heating and reducing substantially the treatment time as compared to traditional algorithms. Out of the six algorithms, 3 were successful in eliminating the pre-focal heating completely. Because these 3 algorithms required no delay between successive movements (except in the last part of the motion), the treatment time was reduced by 93%. Therefore, it will be possible in the future, to achieve treatment time of focused ultrasound therapies shorter than 30 min. The rate of ablated volume achieved with one of the proposed algorithms was 71 cm(3)/h. The intention of this pilot study was to demonstrate that the navigation algorithms play the most important role in reducing pre-focal heating. By evaluating in

  7. A Hybrid Chaos-Particle Swarm Optimization Algorithm for the Vehicle Routing Problem with Time Window

    Directory of Open Access Journals (Sweden)

    Qi Hu

    2013-04-01

    Full Text Available State-of-the-art heuristic algorithms to solve the vehicle routing problem with time windows (VRPTW usually present slow speeds during the early iterations and easily fall into local optimal solutions. Focusing on solving the above problems, this paper analyzes the particle encoding and decoding strategy of the particle swarm optimization algorithm, the construction of the vehicle route and the judgment of the local optimal solution. Based on these, a hybrid chaos-particle swarm optimization algorithm (HPSO is proposed to solve VRPTW. The chaos algorithm is employed to re-initialize the particle swarm. An efficient insertion heuristic algorithm is also proposed to build the valid vehicle route in the particle decoding process. A particle swarm premature convergence judgment mechanism is formulated and combined with the chaos algorithm and Gaussian mutation into HPSO when the particle swarm falls into the local convergence. Extensive experiments are carried out to test the parameter settings in the insertion heuristic algorithm and to evaluate that they are corresponding to the data’s real-distribution in the concrete problem. It is also revealed that the HPSO achieves a better performance than the other state-of-the-art algorithms on solving VRPTW.

  8. Comparison of Co-Temporal Modeling Algorithms on Sparse Experimental Time Series Data Sets.

    Science.gov (United States)

    Allen, Edward E; Norris, James L; John, David J; Thomas, Stan J; Turkett, William H; Fetrow, Jacquelyn S

    2010-01-01

    Multiple approaches for reverse-engineering biological networks from time-series data have been proposed in the computational biology literature. These approaches can be classified by their underlying mathematical algorithms, such as Bayesian or algebraic techniques, as well as by their time paradigm, which includes next-state and co-temporal modeling. The types of biological relationships, such as parent-child or siblings, discovered by these algorithms are quite varied. It is important to understand the strengths and weaknesses of the various algorithms and time paradigms on actual experimental data. We assess how well the co-temporal implementations of three algorithms, continuous Bayesian, discrete Bayesian, and computational algebraic, can 1) identify two types of entity relationships, parent and sibling, between biological entities, 2) deal with experimental sparse time course data, and 3) handle experimental noise seen in replicate data sets. These algorithms are evaluated, using the shuffle index metric, for how well the resulting models match literature models in terms of siblings and parent relationships. Results indicate that all three co-temporal algorithms perform well, at a statistically significant level, at finding sibling relationships, but perform relatively poorly in finding parent relationships.

  9. An Algorithm for Real-Time Pulse Waveform Segmentation and Artifact Detection in Photoplethysmograms.

    Science.gov (United States)

    Fischer, Christoph; Domer, Benno; Wibmer, Thomas; Penzel, Thomas

    2017-03-01

    Photoplethysmography has been used in a wide range of medical devices for measuring oxygen saturation, cardiac output, assessing autonomic function, and detecting peripheral vascular disease. Artifacts can render the photoplethysmogram (PPG) useless. Thus, algorithms capable of identifying artifacts are critically important. However, the published PPG algorithms are limited in algorithm and study design. Therefore, the authors developed a novel embedded algorithm for real-time pulse waveform (PWF) segmentation and artifact detection based on a contour analysis in the time domain. This paper provides an overview about PWF and artifact classifications, presents the developed PWF analysis, and demonstrates the implementation on a 32-bit ARM core microcontroller. The PWF analysis was validated with data records from 63 subjects acquired in a sleep laboratory, ergometry laboratory, and intensive care unit in equal parts. The output of the algorithm was compared with harmonized experts' annotations of the PPG with a total duration of 31.5 h. The algorithm achieved a beat-to-beat comparison sensitivity of 99.6%, specificity of 90.5%, precision of 98.5%, and accuracy of 98.3%. The interrater agreement expressed as Cohen's kappa coefficient was 0.927 and as F-measure was 0.990. In conclusion, the PWF analysis seems to be a suitable method for PPG signal quality determination, real-time annotation, data compression, and calculation of additional pulse wave metrics such as amplitude, duration, and rise time.

  10. A Linear Time Algorithm for the k Maximal Sums Problem

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Jørgensen, Allan Grønlund

    2007-01-01

     k maximal sums problem. We use this algorithm to obtain algorithms solving the two-dimensional k maximal sums problem in O(m 2·n + k) time, where the input is an m ×n matrix with m ≤ n. We generalize this algorithm to solve the d-dimensional problem in O(n 2d − 1 + k) time. The space usage of all......Finding the sub-vector with the largest sum in a sequence of n numbers is known as the maximum sum problem. Finding the k sub-vectors with the largest sums is a natural extension of this, and is known as the k maximal sums problem. In this paper we design an optimal O(n + k) time algorithm for the...... the algorithms can be reduced to O(n d − 1 + k). This leads to the first algorithm for the k maximal sums problem in one dimension using O(n + k) time and O(k) space....

  11. From Massively Parallel Algorithms and Fluctuating Time Horizons to Nonequilibrium Surface Growth

    International Nuclear Information System (INIS)

    Korniss, G.; Toroczkai, Z.; Novotny, M. A.; Rikvold, P. A.

    2000-01-01

    We study the asymptotic scaling properties of a massively parallel algorithm for discrete-event simulations where the discrete events are Poisson arrivals. The evolution of the simulated time horizon is analogous to a nonequilibrium surface. Monte Carlo simulations and a coarse-grained approximation indicate that the macroscopic landscape in the steady state is governed by the Edwards-Wilkinson Hamiltonian. Since the efficiency of the algorithm corresponds to the density of local minima in the associated surface, our results imply that the algorithm is asymptotically scalable. (c) 2000 The American Physical Society

  12. Hitting times of local and global optima in genetic algorithms with very high selection pressure

    Directory of Open Access Journals (Sweden)

    Eremeev Anton V.

    2017-01-01

    Full Text Available The paper is devoted to upper bounds on the expected first hitting times of the sets of local or global optima for non-elitist genetic algorithms with very high selection pressure. The results of this paper extend the range of situations where the upper bounds on the expected runtime are known for genetic algorithms and apply, in particular, to the Canonical Genetic Algorithm. The obtained bounds do not require the probability of fitness-decreasing mutation to be bounded by a constant which is less than one.

  13. TaDb: A time-aware diffusion-based recommender algorithm

    Science.gov (United States)

    Li, Wen-Jun; Xu, Yuan-Yuan; Dong, Qiang; Zhou, Jun-Lin; Fu, Yan

    2015-02-01

    Traditional recommender algorithms usually employ the early and recent records indiscriminately, which overlooks the change of user interests over time. In this paper, we show that the interests of a user remain stable in a short-term interval and drift during a long-term period. Based on this observation, we propose a time-aware diffusion-based (TaDb) recommender algorithm, which assigns different temporal weights to the leading links existing before the target user's collection and the following links appearing after that in the diffusion process. Experiments on four real datasets, Netflix, MovieLens, FriendFeed and Delicious show that TaDb algorithm significantly improves the prediction accuracy compared with the algorithms not considering temporal effects.

  14. Hard Real-Time Task Scheduling in Cloud Computing Using an Adaptive Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Amjad Mahmood

    2017-04-01

    Full Text Available In the Infrastructure-as-a-Service cloud computing model, virtualized computing resources in the form of virtual machines are provided over the Internet. A user can rent an arbitrary number of computing resources to meet their requirements, making cloud computing an attractive choice for executing real-time tasks. Economical task allocation and scheduling on a set of leased virtual machines is an important problem in the cloud computing environment. This paper proposes a greedy and a genetic algorithm with an adaptive selection of suitable crossover and mutation operations (named as AGA to allocate and schedule real-time tasks with precedence constraint on heterogamous virtual machines. A comprehensive simulation study has been done to evaluate the performance of the proposed algorithms in terms of their solution quality and efficiency. The simulation results show that AGA outperforms the greedy algorithm and non-adaptive genetic algorithm in terms of solution quality.

  15. Waiting narratives of lung transplant candidates.

    Science.gov (United States)

    Yelle, Maria T; Stevens, Patricia E; Lanuza, Dorothy M

    2013-01-01

    Before 2005, time accrued on the lung transplant waiting list counted towards who was next in line for a donor lung. Then in 2005 the lung allocation scoring system was implemented, which meant the higher the illness severity scores, the higher the priority on the transplant list. Little is known of the lung transplant candidates who were listed before 2005 and were caught in the transition when the lung allocation scoring system was implemented. A narrative analysis was conducted to explore the illness narratives of seven lung transplant candidates between 2006 and 2007. Arthur Kleinman's concept of illness narratives was used as a conceptual framework for this study to give voice to the illness narratives of lung transplant candidates. Results of this study illustrate that lung transplant candidates expressed a need to tell their personal story of waiting and to be heard. Recommendation from this study calls for healthcare providers to create the time to enable illness narratives of the suffering of waiting to be told. Narrative skills of listening to stories of emotional suffering would enhance how healthcare providers could attend to patients' stories and hear what is most meaningful in their lives.

  16. Waiting Narratives of Lung Transplant Candidates

    Directory of Open Access Journals (Sweden)

    Maria T. Yelle

    2013-01-01

    Full Text Available Before 2005, time accrued on the lung transplant waiting list counted towards who was next in line for a donor lung. Then in 2005 the lung allocation scoring system was implemented, which meant the higher the illness severity scores, the higher the priority on the transplant list. Little is known of the lung transplant candidates who were listed before 2005 and were caught in the transition when the lung allocation scoring system was implemented. A narrative analysis was conducted to explore the illness narratives of seven lung transplant candidates between 2006 and 2007. Arthur Kleinman’s concept of illness narratives was used as a conceptual framework for this study to give voice to the illness narratives of lung transplant candidates. Results of this study illustrate that lung transplant candidates expressed a need to tell their personal story of waiting and to be heard. Recommendation from this study calls for healthcare providers to create the time to enable illness narratives of the suffering of waiting to be told. Narrative skills of listening to stories of emotional suffering would enhance how healthcare providers could attend to patients’ stories and hear what is most meaningful in their lives.

  17. Forecasting Jakarta composite index (IHSG) based on chen fuzzy time series and firefly clustering algorithm

    Science.gov (United States)

    Ningrum, R. W.; Surarso, B.; Farikhin; Safarudin, Y. M.

    2018-03-01

    This paper proposes the combination of Firefly Algorithm (FA) and Chen Fuzzy Time Series Forecasting. Most of the existing fuzzy forecasting methods based on fuzzy time series use the static length of intervals. Therefore, we apply an artificial intelligence, i.e., Firefly Algorithm (FA) to set non-stationary length of intervals for each cluster on Chen Method. The method is evaluated by applying on the Jakarta Composite Index (IHSG) and compare with classical Chen Fuzzy Time Series Forecasting. Its performance verified through simulation using Matlab.

  18. Analysis of bluetooth and wi-fi technology to measure wait times of personal vehicles at Arizona-Mexico ports of entry.

    Science.gov (United States)

    2015-11-01

    Robust travel time data collection is possible using Bluetooth or Wi-Fi technology that : matches anonymous MAC addresses from discoverable electronic devices (e.g., smart phones) : to determine travel time along a roadway segment. Several hundred...

  19. A Real-Time evaluation system for a state-of-charge indication algorithm

    NARCIS (Netherlands)

    Pop, V.; Bergveld, H.J.; Notten, P.H.L.; Regtien, Paulus P.L.

    2005-01-01

    The known methods of State-of-Charge (SoC) indication in portable applications are not accurate enough under all practical conditions. This paper describes a real- time evaluation LabVIEW system for an SoC algorithm, that calculates the SoC in [%] and also the remaining run-time available under the

  20. A real-time evaluation system for a state-of-charge indication algorithm

    NARCIS (Netherlands)

    Pop, V.; Bergveld, H.J.; Notten, P.H.L.; Regtien, P.P.L.

    2005-01-01

    The known methods of State-of-Charge (SoC) indication in portable applications are not accurate enough under all practical conditions. This paper describes a real- time evaluation LabVIEW system for an SoC algorithm, that calculates the SoC in [%] and also the remaining run-time available under the

  1. An Efficient Algorithm for the Optimal Market Timing over Two Stocks

    Institute of Scientific and Technical Information of China (English)

    Hui Li; Hong-zhi An; Guo-fu Wu

    2004-01-01

    In this paper,the optimal trading strategy in timing the market by switching between two stocks is given.In order to deal with a large sample size with a fast turnaround computation time,we propose a class of recursive algorithm.A simulation is given to verify the efiectiveness of our method.

  2. Effective Iterated Greedy Algorithm for Flow-Shop Scheduling Problems with Time lags

    Science.gov (United States)

    ZHAO, Ning; YE, Song; LI, Kaidian; CHEN, Siyu

    2017-05-01

    Flow shop scheduling problem with time lags is a practical scheduling problem and attracts many studies. Permutation problem(PFSP with time lags) is concentrated but non-permutation problem(non-PFSP with time lags) seems to be neglected. With the aim to minimize the makespan and satisfy time lag constraints, efficient algorithms corresponding to PFSP and non-PFSP problems are proposed, which consist of iterated greedy algorithm for permutation(IGTLP) and iterated greedy algorithm for non-permutation (IGTLNP). The proposed algorithms are verified using well-known simple and complex instances of permutation and non-permutation problems with various time lag ranges. The permutation results indicate that the proposed IGTLP can reach near optimal solution within nearly 11% computational time of traditional GA approach. The non-permutation results indicate that the proposed IG can reach nearly same solution within less than 1% computational time compared with traditional GA approach. The proposed research combines PFSP and non-PFSP together with minimal and maximal time lag consideration, which provides an interesting viewpoint for industrial implementation.

  3. 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...

  4. A branch-and-cut algorithm for the Time Window Assignment Vehicle Routing Problem

    NARCIS (Netherlands)

    K. Dalmeijer (Kevin); R. Spliet (Remy)

    2016-01-01

    textabstractThis paper presents a branch-and-cut algorithm for the Time Window Assignment Vehicle Routing Problem (TWAVRP), the problem of assigning time windows for delivery before demand volume becomes known. A novel set of valid inequalities, the precedence inequalities, is introduced and

  5. A wavelet-based PWTD algorithm-accelerated time domain surface integral equation solver

    KAUST Repository

    Liu, Yang; Yucel, Abdulkadir C.; Gilbert, Anna C.; Bagci, Hakan; Michielssen, Eric

    2015-01-01

    © 2015 IEEE. The multilevel plane-wave time-domain (PWTD) algorithm allows for fast and accurate analysis of transient scattering from, and radiation by, electrically large and complex structures. When used in tandem with marching-on-in-time (MOT

  6. A Scheduling Algorithm for Time Bounded Delivery of Packets on the Internet

    NARCIS (Netherlands)

    I. Vaishnavi (Ishan)

    2008-01-01

    htmlabstractThis thesis aims to provide a better scheduling algorithm for Real-Time delivery of packets. A number of emerging applications such as VoIP, Tele-immersive environments, distributed media viewing and distributed gaming require real-time delivery of packets. Currently the scheduling

  7. A parallel algorithm for the two-dimensional time fractional diffusion equation with implicit difference method.

    Science.gov (United States)

    Gong, Chunye; Bao, Weimin; Tang, Guojian; Jiang, Yuewen; Liu, Jie

    2014-01-01

    It is very time consuming to solve fractional differential equations. The computational complexity of two-dimensional fractional differential equation (2D-TFDE) with iterative implicit finite difference method is O(M(x)M(y)N(2)). In this paper, we present a parallel algorithm for 2D-TFDE and give an in-depth discussion about this algorithm. A task distribution model and data layout with virtual boundary are designed for this parallel algorithm. The experimental results show that the parallel algorithm compares well with the exact solution. The parallel algorithm on single Intel Xeon X5540 CPU runs 3.16-4.17 times faster than the serial algorithm on single CPU core. The parallel efficiency of 81 processes is up to 88.24% compared with 9 processes on a distributed memory cluster system. We do think that the parallel computing technology will become a very basic method for the computational intensive fractional applications in the near future.

  8. Towards Real-Time Detection of Gait Events on Different Terrains Using Time-Frequency Analysis and Peak Heuristics Algorithm.

    Science.gov (United States)

    Zhou, Hui; Ji, Ning; Samuel, Oluwarotimi Williams; Cao, Yafei; Zhao, Zheyi; Chen, Shixiong; Li, Guanglin

    2016-10-01

    Real-time detection of gait events can be applied as a reliable input to control drop foot correction devices and lower-limb prostheses. Among the different sensors used to acquire the signals associated with walking for gait event detection, the accelerometer is considered as a preferable sensor due to its convenience of use, small size, low cost, reliability, and low power consumption. Based on the acceleration signals, different algorithms have been proposed to detect toe off (TO) and heel strike (HS) gait events in previous studies. While these algorithms could achieve a relatively reasonable performance in gait event detection, they suffer from limitations such as poor real-time performance and are less reliable in the cases of up stair and down stair terrains. In this study, a new algorithm is proposed to detect the gait events on three walking terrains in real-time based on the analysis of acceleration jerk signals with a time-frequency method to obtain gait parameters, and then the determination of the peaks of jerk signals using peak heuristics. The performance of the newly proposed algorithm was evaluated with eight healthy subjects when they were walking on level ground, up stairs, and down stairs. Our experimental results showed that the mean F1 scores of the proposed algorithm were above 0.98 for HS event detection and 0.95 for TO event detection on the three terrains. This indicates that the current algorithm would be robust and accurate for gait event detection on different terrains. Findings from the current study suggest that the proposed method may be a preferable option in some applications such as drop foot correction devices and leg prostheses.

  9. A Method Based on Dial's Algorithm for Multi-time Dynamic Traffic Assignment

    Directory of Open Access Journals (Sweden)

    Rongjie Kuang

    2014-03-01

    Full Text Available Due to static traffic assignment has poor performance in reflecting actual case and dynamic traffic assignment may incurs excessive compute cost, method of multi-time dynamic traffic assignment combining static and dynamic traffic assignment balances factors of precision and cost effectively. A method based on Dial's logit algorithm is proposed in the article to solve the dynamic stochastic user equilibrium problem in dynamic traffic assignment. Before that, a fitting function that can proximately reflect overloaded traffic condition of link is proposed and used to give corresponding model. Numerical example is given to illustrate heuristic procedure of method and to compare results with one of same example solved by other literature's algorithm. Results show that method based on Dial's algorithm is preferable to algorithm from others.

  10. Mathematical model of rhodium self-powered detectors and algorithms for correction of their time delay

    International Nuclear Information System (INIS)

    Bur'yan, V.I.; Kozlova, L.V.; Kuzhil', A.S.; Shikalov, V.F.

    2005-01-01

    The development of algorithms for correction of self-powered neutron detector (SPND) inertial is caused by necessity to increase the fast response of the in-core instrumentation systems (ICIS). The increase of ICIS fast response will permit to monitor in real time fast transient processes in the core, and in perspective - to use the signals of rhodium SPND for functions of emergency protection by local parameters. In this paper it is proposed to use mathematical model of neutron flux measurements by means of SPND in integral form for creation of correction algorithms. This approach, in the case, is the most convenient for creation of recurrent algorithms for flux estimation. The results of comparison for estimation of neutron flux and reactivity by readings of ionization chambers and SPND signals, corrected by proposed algorithms, are presented [ru

  11. A Combination of Genetic Algorithm and Particle Swarm Optimization for Vehicle Routing Problem with Time Windows.

    Science.gov (United States)

    Xu, Sheng-Hua; Liu, Ji-Ping; Zhang, Fu-Hao; Wang, Liang; Sun, Li-Jian

    2015-08-27

    A combination of genetic algorithm and particle swarm optimization (PSO) for vehicle routing problems with time windows (VRPTW) is proposed in this paper. The improvements of the proposed algorithm include: using the particle real number encoding method to decode the route to alleviate the computation burden, applying a linear decreasing function based on the number of the iterations to provide balance between global and local exploration abilities, and integrating with the crossover operator of genetic algorithm to avoid the premature convergence and the local minimum. The experimental results show that the proposed algorithm is not only more efficient and competitive with other published results but can also obtain more optimal solutions for solving the VRPTW issue. One new well-known solution for this benchmark problem is also outlined in the following.

  12. Comparison of SAR calculation algorithms for the finite-difference time-domain method

    International Nuclear Information System (INIS)

    Laakso, Ilkka; Uusitupa, Tero; Ilvonen, Sami

    2010-01-01

    Finite-difference time-domain (FDTD) simulations of specific-absorption rate (SAR) have several uncertainty factors. For example, significantly varying SAR values may result from the use of different algorithms for determining the SAR from the FDTD electric field. The objective of this paper is to rigorously study the divergence of SAR values due to different SAR calculation algorithms and to examine if some SAR calculation algorithm should be preferred over others. For this purpose, numerical FDTD results are compared to analytical solutions in a one-dimensional layered model and a three-dimensional spherical object. Additionally, the implications of SAR calculation algorithms for dosimetry of anatomically realistic whole-body models are studied. The results show that the trapezium algorithm-based on the trapezium integration rule-is always conservative compared to the analytic solution, making it a good choice for worst-case exposure assessment. In contrast, the mid-ordinate algorithm-named after the mid-ordinate integration rule-usually underestimates the analytic SAR. The linear algorithm-which is approximately a weighted average of the two-seems to be the most accurate choice overall, typically giving the best fit with the shape of the analytic SAR distribution. For anatomically realistic models, the whole-body SAR difference between different algorithms is relatively independent of the used body model, incident direction and polarization of the plane wave. The main factors affecting the difference are cell size and frequency. The choice of the SAR calculation algorithm is an important simulation parameter in high-frequency FDTD SAR calculations, and it should be explained to allow intercomparison of the results between different studies. (note)

  13. Joint control algorithm in access network

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    To deal with long probing delay and inaccurate probing results in the endpoint admission control method,a joint local and end-to-end admission control algorithm is proposed,which introduces local probing of access network besides end-to-end probing.Through local probing,the algorithm accurately estimated the resource status of the access network.Simulation shows that this algorithm can improve admission control performance and reduce users' average waiting time when the access network is heavily loaded.

  14. The Impact of Patient-to-Patient Interaction in Health Facility Waiting Rooms on Their Perception of Health Professionals.

    Science.gov (United States)

    Willis, William Kent; Ozturk, Ahmet Ozzie; Chandra, Ashish

    2015-01-01

    Patients have to wait in waiting rooms prior to seeing the physician. But there are few studies that demonstrate what they are actually doing in the waiting room. This exploratory study was designed to investigate the types of discussions that patients in the waiting room typically engage in with other patients and how the conversations affected their opinion on general reputation of the clinic, injections/blocks as treatment procedures, waiting time, time spent with the caregiver, overall patient satisfaction, and the pain medication usage policy. The study demonstrates that patient interaction in the waiting room has a positive effect on patient opinion of the pain clinic and the caregivers.

  15. Real Time Optima Tracking Using Harvesting Models of the Genetic Algorithm

    Science.gov (United States)

    Baskaran, Subbiah; Noever, D.

    1999-01-01

    Tracking optima in real time propulsion control, particularly for non-stationary optimization problems is a challenging task. Several approaches have been put forward for such a study including the numerical method called the genetic algorithm. In brief, this approach is built upon Darwinian-style competition between numerical alternatives displayed in the form of binary strings, or by analogy to 'pseudogenes'. Breeding of improved solution is an often cited parallel to natural selection in.evolutionary or soft computing. In this report we present our results of applying a novel model of a genetic algorithm for tracking optima in propulsion engineering and in real time control. We specialize the algorithm to mission profiling and planning optimizations, both to select reduced propulsion needs through trajectory planning and to explore time or fuel conservation strategies.

  16. Brazil well worth the wait

    Energy Technology Data Exchange (ETDEWEB)

    Duey, R.

    1999-11-01

    Oil companies weren't the only ones waiting for Brazil to make up its mind about privatizing its oil and gas industry. Seismic firms are flocking to the area in droves to work their spec magic. Exploratory activities in these large offshore blocks are described.

  17. An Optimal Scheduling Algorithm with a Competitive Factor for Real-Time Systems

    Science.gov (United States)

    1991-07-29

    real - time systems in which the value of a task is proportional to its computation time. The system obtains the value of a given task if the task completes by its deadline. Otherwise, the system obtains no value for the task. When such a system is underloaded (i.e. there exists a schedule for which all tasks meet their deadlines), Dertouzos [6] showed that the earliest deadline first algorithm will achieve 100% of the possible value. We consider the case of a possibly overloaded system and present an algorithm which: 1. behaves like the earliest deadline first

  18. A Study on the Enhanced Best Performance Algorithm for the Just-in-Time Scheduling Problem

    Directory of Open Access Journals (Sweden)

    Sivashan Chetty

    2015-01-01

    Full Text Available The Just-In-Time (JIT scheduling problem is an important subject of study. It essentially constitutes the problem of scheduling critical business resources in an attempt to optimize given business objectives. This problem is NP-Hard in nature, hence requiring efficient solution techniques. To solve the JIT scheduling problem presented in this study, a new local search metaheuristic algorithm, namely, the enhanced Best Performance Algorithm (eBPA, is introduced. This is part of the initial study of the algorithm for scheduling problems. The current problem setting is the allocation of a large number of jobs required to be scheduled on multiple and identical machines which run in parallel. The due date of a job is characterized by a window frame of time, rather than a specific point in time. The performance of the eBPA is compared against Tabu Search (TS and Simulated Annealing (SA. SA and TS are well-known local search metaheuristic algorithms. The results show the potential of the eBPA as a metaheuristic algorithm.

  19. Change detection using landsat time series: A review of frequencies, preprocessing, algorithms, and applications

    Science.gov (United States)

    Zhu, Zhe

    2017-08-01

    The free and open access to all archived Landsat images in 2008 has completely changed the way of using Landsat data. Many novel change detection algorithms based on Landsat time series have been developed We present a comprehensive review of four important aspects of change detection studies based on Landsat time series, including frequencies, preprocessing, algorithms, and applications. We observed the trend that the more recent the study, the higher the frequency of Landsat time series used. We reviewed a series of image preprocessing steps, including atmospheric correction, cloud and cloud shadow detection, and composite/fusion/metrics techniques. We divided all change detection algorithms into six categories, including thresholding, differencing, segmentation, trajectory classification, statistical boundary, and regression. Within each category, six major characteristics of different algorithms, such as frequency, change index, univariate/multivariate, online/offline, abrupt/gradual change, and sub-pixel/pixel/spatial were analyzed. Moreover, some of the widely-used change detection algorithms were also discussed. Finally, we reviewed different change detection applications by dividing these applications into two categories, change target and change agent detection.

  20. Waiting for the Payday?

    DEFF Research Database (Denmark)

    Arora, Ashish; Fosfuri, Andrea; Rønde, Thomas

    Most technology startups are set up for exit through acquisition by large corporations. In choosing when to sell, startups face a tradeoff. Early acquisitions reduce execution errors but later acquisitions improve the likelihood of finding a better match because there are fewer buyers in the early...... market as early acquisitions require costly absorptive capacity. Moreover, the decision of buyers to invest in absorptive capacity is related to the decision of startups on the timing of the exit sale. In this paper, we build a model to capture this complexity and the related tradeoffs. We find......, when the timing of exit is a tactical choice, i.e., startups can choose to go late after observing the early offers, there are too many early acquisitions and too much investment in absorptive capacity by incumbents....