What Is Six Hours Worth? The Impact of Lead Time on Tropical-Storm Preparation Decisions

2020 ◽  
Vol 17 (1) ◽  
pp. 9-23
Author(s):  
Eva D. Regnier

Emergency managers must make high-stakes decisions regarding preparation for tropical storms when there is still considerable uncertainty regarding the storm’s impacts. Forecast quality improves as lead time until the forecast events declines. Reducing the lead time required for preparation decisions can substantially improve the quality of forecasts available for decision making and thereby, reduce the expected total costs of preparations plus storm damage. Measures of forecast quality are only indirectly linked to their value in preparation decisions and changes in the parameters of those decisions—in particular lead time. This paper provides decision-relevant measures of the quality of recent National Hurricane Center forecasts from the 2014–2018 seasons, which can be used to evaluate reductions in decision lead time in terms of false alarm rate, missed detections, and expected annual costs. For decision makers in some regions with decision lead times of 48–72 hours—typical for evacuation decisions—every 6-hour reduction in required lead time can reduce the false alarm rate by more than 10%.

2020 ◽  
Vol 90 (19-20) ◽  
pp. 2304-2321
Author(s):  
Olivia Ho-Yi Fung ◽  
Joanne Yip ◽  
Mei-Chun Cheung ◽  
Kit-Lun Yick ◽  
Kenny Yat-Hong Kwan ◽  
...  

Bracing is the most common non-operative treatment option for patients with adolescent idiopathic scoliosis (AIS). However, existing brace designs have deficiencies, including a long production lead time and low patient compliance caused by the negative impacts of bracing on quality of life (QoL). The aim of this study was to address these problems by developing a new textile-based scoliosis brace in accordance with the biomechanics used in the existing braces for spinal correction. A case study of interface pressure had been carried out to determine the optimum combination of pads to be used in the proposed brace to correct a scoliotic spine. AIS patients who were undergoing hard brace treatment were recruited to complete a questionnaire (BrQ) on hard braces and on the proposed brace. The BrQ scores of the two types of braces were compared to assess their respective impacts on the QoL. The findings show that the proposed brace can address the issue of patient compliance by reducing the impact of bracing on QoL, and shorten the production lead time through incorporation of the mass customization concept into the design. Similar to most of the commonly-used scoliosis braces, the selected combination of pads used in the proposed brace for spinal correction shows a sufficient amount of exerted pressure and a similar function of active spinal correction.


2018 ◽  
Vol 34 (S1) ◽  
pp. 20-21
Author(s):  
Shaun Harris ◽  
Deborah Fitzsimmons ◽  
Roshan das Nair ◽  
Lucy Bradshaw

Introduction:People with traumatic brain injuries (TBIs) commonly report memory impairments which are persistent, debilitating, and reduce quality of life. As part of the Rehabilitation of Memory in Brain Injury trial, a cost-effectiveness analysis was undertaken to examine the comparative costs and effects of a group memory rehabilitation program for people with TBI.Methods:Individual-level cost and outcome data were collected. Patients were randomized to usual care (n=157) or usual care plus memory rehabilitation (n=171). The primary outcome for the economic analysis was the EuroQol-5D quality of life score at 12 months. A UK NHS costing perspective was used. Missing data was addressed by multiple imputation. One-way sensitivity analyses examined the impact of varying different parameters, and the impact of available cases, on base case findings whilst non-parametric bootstrapping examined joint uncertainty.Results:At 12 months, the intervention was GBP 26.89 (USD 35.76) (SE 249.15) cheaper than usual care; but this difference was statistically non-significant (p=0.914). At 12 months, a QALY loss of −0.007 was observed in the intervention group confidence interval (95% CI: −0.025–0.012) and a QALY gain seen in the usual care group 0.004 (95% CI: -0.017–0.025). This difference was not statistically significant (p=0.442). The base case analysis gave an ICER of GBP 2,445 (USD 3,252) reflecting that the intervention was less effective and less costly compared to usual care. Sensitivity analyses illustrated considerable uncertainty. When joint uncertainty was examined, the probability of the intervention being cost-effective at a willingness-to-pay threshold of GBP 20,000 per QALY gain was 29 percent and 24 percent at GBP 30,000.Conclusions:Our cost-utility analysis indicates that memory rehabilitation was cheaper but less effective than usual care but these findings must be interpreted in the light of small statistically non–significant differences and considerable uncertainty was evident. The ReMemBrIn intervention is unlikely to be considered cost-effective for people with TBI.


2019 ◽  
Vol 27 (1) ◽  
pp. 41-46
Author(s):  
Tomasz K. Czarkowski ◽  
Andrzej Kapusta

Abstract The aim of the study was to compare the catch efficiency of novice and experienced anglers float fishing with different hook types. The mortality of fish that were caught and released was determined based on the experience of the angler and the type of hook used. The mean catch rates of the experienced angler was 46.7 fish per hour, while that of the novice angler was 33.7 fish per hour. The landing efficiency of fish using hooks with micro-barbs was higher than that with barbless hooks. Angling experience had a significant impact on the mean time required to unhook caught fish and also on the mortality of the fish released. The lowest mortality was noted in fish caught by experienced anglers fishing with barbless hooks. The results of the study suggest that angling experience does not have a great impact on parameters characterizing the quality of angling catches. The efficiency of float fishing performed by novice and experienced anglers was similar. Differences were noted in the time required to unhook the fish and in the mortality of the fish released.


Author(s):  
Faheema Hisham ◽  
Jonathan M. Bunker ◽  
Ashish Bhaskar

The effectiveness of an on-street bus facility depends on the volume of general traffic sharing the buses’ travel lane. The Transit Capacity and Quality of Service Manual (TCQSM) methodology estimates capacity of a bus facility based on the operation of critical stops. The aim of this study is to understand better the performance of an on-street, mid-block, off-line bus stop by relating bus stop capacity to adjacent lane traffic volume. The contributions of this paper are twofold. First, the TCQSM methodology incorporates the effect of adjacent lane traffic volume on bus stop capacity at mid-block bus stops through its effect on re-entry delay, but it does not consider the impact of the bus stop itself on adjacent lane traffic capacity. This paper introduces a novel methodology to estimate the additional time required to accommodate adjacent lane traffic volume under saturated conditions. Second, the TCQSM methodology does not reflect the effect on re-entry delay of a yield-to-bus (YTB) rule, which is mandatory by law in some jurisdictions. This paper modifies the current TCQSM methodology by allowing for the YTB rule. A microscopic simulation model is developed in order to cross-validate the theoretical model developed.


2017 ◽  
Vol 56 (3) ◽  
pp. 651-665
Author(s):  
Vivek Srikrishnan ◽  
George S. Young ◽  
Jeffrey R. S. Brownson

AbstractThe intermittency of solar power production is dependent on the evolution and advection of the nearby cloud field. A key problem related to solar energy integration is the improvement of 1-h-ahead forecasts to reduce the impact of intermittency on power systems operations. Many solar forecasts explicitly or implicitly assume Taylor’s hypothesis. While such advection-only forecasts can be presumed to be valid across sufficiently short time scales, it is not clear how rapidly the skill of such a forecast decays with increased lead time. As the goal is to improve the quality of 1-h-ahead forecasts, this work focuses on quantifying the skill of cloud-track wind-based cumulus-dominated cloud field forecasts with respect to lead time. No explicit connection is drawn to the quality of solar forecasts because of the importance of separating two potential sources of error: cloud field forecasting and radiative transfer estimation. It is found that the cumulus field forecast skill begins to asymptotically approach a minimum at lead times of beyond 30 min, suggesting that advection-only forecasts in a cumulus-dominated environment should not be relied upon for 1-h-ahead point forecasts used by radiative transfer methods to estimate solar power production. A first attempt at forming a probabilistic forecast that can quantify this increasing uncertainty when using advection-only methods is presented.


2012 ◽  
Vol 19 (4) ◽  
pp. 753-761 ◽  
Author(s):  
Yanlong Cao ◽  
Yuanfeng He ◽  
Huawen Zheng ◽  
Jiangxin Yang

In order to reduce the false alarm rate and missed detection rate of a Loose Parts Monitoring System (LPMS) for Nuclear Power Plants, a new hybrid method combining Linear Predictive Coding (LPC) and Support Vector Machine (SVM) together to discriminate the loose part signal is proposed. The alarm process is divided into two stages. The first stage is to detect the weak burst signal for reducing the missed detection rate. Signal is whitened to improve the SNR, and then the weak burst signal can be detected by checking the short-term Root Mean Square (RMS) of the whitened signal. The second stage is to identify the detected burst signal for reducing the false alarm rate. Taking the signal's LPC coefficients as its characteristics, SVM is then utilized to determine whether the signal is generated by the impact of a loose part. The experiment shows that whitening the signal in the first stage can detect a loose part burst signal even at very low SNR and thusly can significantly reduce the rate of missed detection. In the second alarm stage, the loose parts' burst signal can be distinguished from pulse disturbance by using SVM. Even when the SNR is −15 dB, the system can still achieve a 100% recognition rate


Author(s):  
Makenzie J. Krocak ◽  
Harold E. Brooks

AbstractWhile many studies have looked at the quality of forecast products, few have attempted to understand the relationship between them. We begin to consider whether or not such an influence exists by analyzing storm-based tornado warning product metrics with respect to whether they occurred within a severe weather watch and, if so, what type of watch they occurred within.The probability of detection, false alarm ratio, and lead time all show a general improvement with increasing watch severity. In fact, the probability of detection increased more as a function of watch-type severity than the change in probability of detection during the time period of analysis. False alarm ratio decreased as watch type increased in severity, but with a much smaller magnitude than the difference in probability of detection. Lead time also improved with an increase in watch-type severity. Warnings outside of any watch had a mean lead time of 5.5 minutes, while those inside of a particularly dangerous situation tornado watch had a mean lead time of 15.1 minutes. These results indicate that the existence and type of severe weather watch may have an influence on the quality of tornado warnings. However, it is impossible to separate the influence of weather watches from possible differences in warning strategy or differences in environmental characteristics that make it more or less challenging to warn for tornadoes. Future studies should attempt to disentangle these numerous influences to assess how much influence intermediate products have on downstream products.


2013 ◽  
Vol 28 (2) ◽  
pp. 489-503 ◽  
Author(s):  
Siebren de Haan ◽  
Gert-Jan Marseille ◽  
Paul de Valk ◽  
John de Vries

Abstract Denial experiments, also denoted observing system experiments (OSEs), are used to determine the impact of an observing system on the forecast quality of a numerical weather prediction (NWP) model. When the impact is neutral or positive, new observations from this observing system may be admitted to an operational forecasting system based on that NWP model. A drawback of the method applied in most denial experiments is that it neglects the operational time constraint on the delivery of observations. In a 10-week twin experiment with the operational High-Resolution Limited-Area Model (HIRLAM) at KNMI, the impact of additional ocean surface wind observations from the Advanced Scatterometer (ASCAT) on the forecast quality of the model has been verified under operational conditions. In the experiment, the operational model was used as reference, parallel to an augmented system in which the ASCAT winds were assimilated actively. Objective verification of the forecast with independent wind observations from moored buoys and ASCAT winds revealed a slight improvement in forecast skill as measured by a decrease in observation-minus-forecast standard deviation in the wind components for the short range (up to 24 h). A subjective analysis in a case study showed a realistic deepening of a low pressure system over the North Atlantic near the coast of Ireland through the assimilation of scatterometer data that were verified with radiosonde observations over Ireland. Based on these results, the decision was made to include ASCAT in operations at the next upgrade of the forecasting system.


2019 ◽  
Author(s):  
Dominique T Vuvan ◽  
Olivia P. Lewandowska ◽  
Mark A. Schmuckler

Although the relation between tonality and musical memory has been fairly well-studied, less is known regarding the contribution of tonal-schematic expectancies to this relation. Three experiments investigated the influence of tonal expectancies on memory for single tones in a tonal melodic context. In the first experiment, listener responses indicated superior recognition of both expected and unexpected targets in a major tonal context than for moderately expected targets. Importantly, and in support of previous work on false memories, listener responses also revealed a higher false alarm rate for expected than unexpected targets. These results indicate roles for tonal schematic congruency as well as distinctiveness in memory for melodic tones. The second experiment utilized minor melodies, which weakened tonal expectancies since the minor tonality can be represented in three forms simultaneously. Finally, tonal expectancies were abolished entirely in the third experiment through the use of atonal melodies. Accordingly, the expectancy-based results observed in the first experiment were disrupted in the second experiment, and disappeared in the third experiment. These results are discussed in light of schema theory, musical expectancy, and classic memory work on the availability and distinctiveness heuristics.


2016 ◽  
Vol 20 (13) ◽  
pp. 1-588 ◽  
Author(s):  
Louise Crathorne ◽  
Nicola Huxley ◽  
Marcela Haasova ◽  
Tristan Snowsill ◽  
Tracey Jones-Hughes ◽  
...  

BackgroundAnaemia is a common side effect of cancer treatments and can lead to a reduction in quality of life. Erythropoiesis-stimulating agents (ESAs) are licensed for use in conjunction with red blood cell transfusions to improve cancer treatment-induced anaemia (CIA).ObjectiveTo investigate the effectiveness and cost-effectiveness of ESAs in anaemia associated with cancer treatment (specifically chemotherapy).Data sourcesThe following databases were searched from 2004 to 2013: The Cochrane Library, MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, Web of Science, Cumulative Index to Nursing and Allied Health Literature, British Nursing Index, Health Management Information Consortium, Current Controlled Trials and ClinicalTrials.gov. The US Food and Drug Administration and European Medicines Agency websites were also searched. Bibliographies of included papers were scrutinised for further potentially includable studies.Review methodsThe clinical effectiveness review followed principles published by the NHS Centre for Reviews and Dissemination. Randomised controlled trials (RCTs), or systematic reviews of RCTs, of ESAs (epoetin or darbepoetin) for treating people with CIA were eligible for inclusion in the review. Comparators were best supportive care, placebo or other ESAs. Anaemia- and malignancy-related outcomes, health-related quality of life (HRQoL) and adverse events (AEs) were evaluated. When appropriate, data were pooled using meta-analysis. An empirical health economic model was developed comparing ESA treatment with no ESA treatment. The model comprised two components: one evaluating short-term costs and quality-adjusted life-years (QALYs) (while patients are anaemic) and one evaluating long-term QALYs. Costs and benefits were discounted at 3.5% per annum. Probabilistic and univariate deterministic sensitivity analyses were performed.ResultsOf 1457 titles and abstracts screened, 23 studies assessing ESAs within their licensed indication (based on start dose administered) were included in the review. None of the RCTs were completely aligned with current European Union licenses. The results suggest a clinical benefit from ESAs for anaemia-related outcomes and an improvement in HRQoL scores. The impact of ESAs on AEs and survival remains highly uncertain, although point estimates are lower, confidence intervals are wide and not statistically significant. Base-case incremental cost-effectiveness ratios (ICERs) for ESA treatment compared with no ESA treatment ranged from £19,429 to £35,018 per QALY gained, but sensitivity and scenario analyses demonstrate considerable uncertainty in these ICERs, including the possibility of overall health disbenefit. All ICERs were sensitive to survival and cost.LimitationsThe relative effectiveness of ESAs was not addressed; all ESAs were assumed to have equivalent efficacy. No studies were completely aligned with their European labelling beyond the starting dose evaluated. There is questionable generalisability given that the included trials were published > 20 years ago and there have been many changes to chemotherapy as well as to the quality of supportive treatment. Trial quality was moderate or poor and there was considerable unexplained heterogeneity for a number of outcomes, particularly survival, and evidence of publication bias. Adjustments were not made to account for multiple testing.ConclusionsESAs could be cost-effective when used closer to licence, but there is considerable uncertainty, mainly because of unknown impacts on overall survival.Study registrationThis study is registered as PROSPERO CRD42013005812.FundingThe National Institute for Health Research Health Technology Assessment programme.


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