Design of Boiler Welding for Improvement of Lifetime and Cost Control.

Science.gov (United States)

Thong-On, Atcharawadi; Boonruang, Chatdanai

2016-11-03

Fe-2.25Cr-1Mo a widely used material for headers and steam tubes of boilers. Welding of steam tube to header is required for production of boiler. Heat affected zone of the weld can have poor mechanical properties and poor corrosion behavior leading to weld failure. The cost of material used for steam tube and header of boiler should be controlled. This study propose a new materials design for boiler welding to improve the lifetime and cost control, using tungsten inert gas (TIG) welding of Fe-2.25Cr-1Mo tube to carbon steel pipe with chromium-containing filler. The cost of production could be reduced by the use of low cost material such as carbon steel pipe for boiler header. The effect of chromium content on corrosion behavior of the weld was greater than that of the microstructure. The lifetime of the welded boiler can be increased by improvement of mechanical properties and corrosion behavior of the heat affected zone.

Design of Boiler Welding for Improvement of Lifetime and Cost Control

Directory of Open Access Journals (Sweden)

Atcharawadi Thong-On

2016-11-01

Full Text Available Fe-2.25Cr-1Mo a widely used material for headers and steam tubes of boilers. Welding of steam tube to header is required for production of boiler. Heat affected zone of the weld can have poor mechanical properties and poor corrosion behavior leading to weld failure. The cost of material used for steam tube and header of boiler should be controlled. This study propose a new materials design for boiler welding to improve the lifetime and cost control, using tungsten inert gas (TIG welding of Fe-2.25Cr-1Mo tube to carbon steel pipe with chromium-containing filler. The cost of production could be reduced by the use of low cost material such as carbon steel pipe for boiler header. The effect of chromium content on corrosion behavior of the weld was greater than that of the microstructure. The lifetime of the welded boiler can be increased by improvement of mechanical properties and corrosion behavior of the heat affected zone.

Primary treatments for clinically localised prostate cancer: a comprehensive lifetime cost-utility analysis.

Science.gov (United States)

Cooperberg, Matthew R; Ramakrishna, Naren R; Duff, Steven B; Hughes, Kathleen E; Sadownik, Sara; Smith, Joseph A; Tewari, Ashutosh K

2013-03-01

WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: Multiple treatment alternatives exist for localised prostate cancer, with few high-quality studies directly comparing their comparative effectiveness and costs. The present study is the most comprehensive cost-effectiveness analysis to date for localised prostate cancer, conducted with a lifetime horizon and accounting for survival, health-related quality-of-life, and cost impact of secondary treatments and other downstream events, as well as primary treatment choices. The analysis found minor differences, generally slightly favouring surgical methods, in quality-adjusted life years across treatment options. However, radiation therapy (RT) was consistently more expensive than surgery, and some alternatives, e.g. intensity-modulated RT for low-risk disease, were dominated - that is, both more expensive and less effective than competing alternatives. To characterise the costs and outcomes associated with radical prostatectomy (open, laparoscopic, or robot-assisted) and radiation therapy (RT: dose-escalated three-dimensional conformal RT, intensity-modulated RT, brachytherapy, or combination), using a comprehensive, lifetime decision analytical model. A Markov model was constructed to follow hypothetical men with low-, intermediate-, and high-risk prostate cancer over their lifetimes after primary treatment; probabilities of outcomes were based on an exhaustive literature search yielding 232 unique publications. In each Markov cycle, patients could have remission, recurrence, salvage treatment, metastasis, death from prostate cancer, and death from other causes. Utilities for each health state were determined, and disutilities were applied for complications and toxicities of treatment. Costs were determined from the USA payer perspective, with incorporation of patient costs in a sensitivity analysis. Differences across treatments in quality-adjusted life years across methods were modest, ranging from 10.3 to

Modelling lifetime cost consequences of toric compared with standard IOLs in cataract surgery of astigmatic patients in four European countries.

Science.gov (United States)

Laurendeau, C; Lafuma, A; Berdeaux, G

2009-09-01

To compare the lifetime costs of freeing astigmatic patients from spectacles after bilateral cataract surgery implanting toric intraocular lenses (IOLs: i.e., Acrysof Toric) versus monofocal IOLs, in France, Italy, Germany and Spain. A Markov model followed patient cohorts from cataract surgery until death. Prevalence rates of patients not needing spectacles and the types of spectacles prescribed for those requiring them were obtained from clinical trials and national surveys. The economic perspective was societal. Mortality rates were incorporated into the model. Discount rates were applied. A sensitivity analysis was performed on non-discounted costs. Fewer patients with toric IOLs needed spectacles for distance vision than patients with monofocal IOLs. With monofocal IOLs more than 66% of patients needed complex spectacles compared to less than 25% implanted with toric IOLs. In France and Italy, toric IOLs reduced overall costs relative to otherwise high spectacle costs after cataract surgery. Savings were 897.0 euros (France), 822.5 euros (Germany), 895.8 euros (Italy) and 391.6 euros (Spain), without discounting. On applying a 3% discount rate the costs became 691.7 euros, 646.4 euros, 693.9 euros and 308.2 euros, respectively. Bilateral toric IOL implants in astigmatic patients decreased spectacle dependence for distance vision and the need for complex spectacles. The economic consequences for patients depended on the national spectacle costs usually incurred after cataract surgery.

The lifetime costs of overweight and obesity in childhood and adolescence: a systematic review.

Science.gov (United States)

Hamilton, D; Dee, A; Perry, I J

2018-04-01

Research into lifetime costs of obesity in childhood is growing. This review synthesizes that knowledge. A computerized search of the international literature since 2000 was conducted. Mean total lifetime healthcare and productivity costs were estimated and inflated to 2014 Irish euros. This resulted in 13 published articles. The methodology used in these studies varied widely, and only one study estimated both healthcare and productivity costs. Cognizant of this heterogeneity, the mean total lifetime cost of a child or adolescent with obesity was €149,206 (range, €129,410 to €178,933) for a boy and €148,196 (range, €136,576 to €173,842) for a girl. This was divided into an average of €16,229 (range, €6,580 to €35,810) in healthcare costs and €132,977 (range, €122,830 to €143,123) in productivity losses for boys and €19,636 (range, €8,016 to €45,283) and €128,560, respectively, for girls. Income penalty accounted for the greater part of productivity costs, amounting to €97,118 (range, €86,971 to €107,264) per male adolescent with obesity and €126,108 per female adolescent. Healthcare costs and income penalty appear greater in girls while costs because of workdays lost seem greater in boys. There is proportionality between body mass index and costs. Productivity costs are greater than healthcare costs. © 2017 World Obesity Federation.

Lifetime cost of everolimus vs axitinib in patients with advanced renal cell carcinoma who failed prior sunitinib therapy in the US.

Science.gov (United States)

Perrin, Allison; Sherman, Steven; Pal, Sumanta; Chua, Andrew; Gorritz, Magdaliz; Liu, Zhimei; Wang, Xufang; Culver, Kenneth; Casciano, Roman; Garrison, Louis P

2015-03-01

Everolimus and axitinib are approved in the US to treat patients with advanced renal cell carcinoma (RCC) after failure on sunitinib or sorafenib, and one prior systemic therapy (e.g., sunitinib), respectively. Two indirect comparisons performed to evaluate progression-free survival in patients treated with everolimus vs axitinib suggested similar efficacy between the two treatments. Therefore, this analysis compares the lifetime costs of these two therapies among sunitinib-refractory advanced RCC patients from a US payer perspective. A Markov model was developed to simulate a cohort of sunitinib-refractory advanced RCC patients and estimate the cost of treating patients with everolimus vs axitinib. The following health states were included: stable disease without adverse events (AEs), stable disease with AEs, disease progression (PD), and death. The model included the following resources: active treatments, post-progression treatments, adverse events, physician and nurse visits, scans and tests, and palliative care. Resource utilization inputs were derived from a US claims database analysis. Additionally, a 3% annual discount rate was applied to costs, and the robustness of the model results was tested by conducting sensitivity analyses, including those on dosing scheme and post-progression treatment costs. Base case results demonstrated that patients treated with everolimus cost an average of $12,985 (11%) less over their lifetimes than patients treated with axitinib. The primary difference in costs was related to active treatment, which was largely driven by axitinib's higher dose intensity. RESULTS remained consistent across sensitivity analyses for AE and PD treatment costs, as well as dose intensity and discount rates. The results suggest that everolimus likely leads to lower lifetime costs than axitinib for sunitinib-refractory advanced RCC patients in the US.

Cost and Performance Model for Photovoltaic Systems

Science.gov (United States)

Borden, C. S.; Smith, J. H.; Davisson, M. C.; Reiter, L. J.

1986-01-01

Lifetime cost and performance (LCP) model assists in assessment of design options for photovoltaic systems. LCP is simulation of performance, cost, and revenue streams associated with photovoltaic power systems connected to electric-utility grid. LCP provides user with substantial flexibility in specifying technical and economic environment of application.

[The costs for different voice prostheses depending on the lifetime].

Science.gov (United States)

Schuldt, T; Ovari, A; Dommerich, S

2013-06-01

Voice prostheses are available in different types of architecture und from different producers. Especially the ones with antifungal properties are characterized by a high pricing. The aim of this paper is to check, whether these prices are reflected by the prosthesis life time.A Benchmarking with usage of mean lifetime and prosthesis costs. Comparing Provox 1, Provox 2, Provox Vega, Provox ActiValve, ESKA-Herrmann, Blom Singer Classic, Phonax, Blom Singer Advantage.The voice prosthesis Provox 1 offers the best price-lifetime-ratio (1.0). It's 6.7-times higher than the one of the Provox ActiValve (0.15). In addition, the classic prostheses Provox 2 (0.53), Blom Singer Classic (0.54) and ESKA-Herrmann (0.72) offer a good ratio compared to Provox 1, too.The mean lifetime of the voice prostheses do not reflect the pricing. The Provox 1 offers the best ratio and should be used as a reference in pricing the prostheses. © Georg Thieme Verlag KG Stuttgart · New York.

Optimizing design of converters using power cycling lifetime models

DEFF Research Database (Denmark)

Nielsen, Rasmus Ørndrup; Munk-Nielsen, Stig

2015-01-01

Converter power cycling lifetime depends heavily on converter operation point. A lifetime model of a single power module switched mode power supply with wide input voltage range is shown. A lifetime model is created using a power loss model, a thermal model and a model for power cycling capability...... with a given mission profile. A method to improve the expected lifetime of the converter is presented, taking into account switching frequency, input voltage and transformer turns ratio....

Modelling the cost effectiveness of antidepressant treatment in primary care.

Science.gov (United States)

Revicki, D A; Brown, R E; Palmer, W; Bakish, D; Rosser, W W; Anton, S F; Feeny, D

1995-12-01

The aim of this study was to estimate the cost effectiveness of nefazodone compared with imipramine or fluoxetine in treating women with major depressive disorder. Clinical decision analysis and a Markov state-transition model were used to estimate the lifetime health outcomes and medical costs of 3 antidepressant treatments. The model, which represents ideal primary care practice, compares treatment with nefazodone to treatment with either imipramine or fluoxetine. The economic analysis was based on the healthcare system of the Canadian province of Ontario, and considered only direct medical costs. Health outcomes were expressed as quality-adjusted life years (QALYs) and costs were in 1993 Canadian dollars ($Can; $Can1 = $US0.75, September 1995). Incremental cost-utility ratios were calculated comparing the relative lifetime discounted medical costs and QALYs associated with nefazodone with those of imipramine or fluoxetine. Data for constructing the model and estimating necessary parameters were derived from the medical literature, clinical trial data, and physician judgement. Data included information on: Ontario primary care physicians' clinical management of major depression; medical resource use and costs; probabilities of recurrence of depression; suicide rates; compliance rates; and health utilities. Estimates of utilities for depression-related hypothetical health states were obtained from patients with major depression (n = 70). Medical costs and QALYs were discounted to present value using a 5% rate. Sensitivity analyses tested the assumptions of the model by varying the discount rate, depression recurrence rates, compliance rates, and the duration of the model. The base case analysis found that nefazodone treatment costs $Can1447 less per patient than imipramine treatment (discounted lifetime medical costs were $Can50,664 vs $Can52,111) and increases the number of QALYs by 0.72 (13.90 vs 13.18). Nefazodone treatment costs $Can14 less than fluoxetine

The use of lifetime functions in the optimization of interventions on existing bridges considering maintenance and failure costs

Energy Technology Data Exchange (ETDEWEB)

Yang, Seung-Ie [Department of Civil, Enviromental, and Architectural Enginnering, University of Colorado, Campus Box 428, Boulder, CO 80309-0428 (United States)]. E-mail: yangsione@dreamwiz.com; Frangopol, Dan M. [Department of Civil, Enviromental, and Architectural Enginnering, University of Colorado, Campus Box 428, Boulder, CO 80309-0428 (United States)]. E-mail: dan.frangopol@colorado.edu; Kawakami, Yoriko [Hanshin Expressway Public Corporation, Kobe Maintenance Department, 16-1 Shinko-cho Chuo-ku Kobe City, Hyogo, 650-0041 (Japan)]. E-mail: yoriko-kawakami@hepc.go.jp; Neves, Luis C. [Department of Civil, Enviromental, and Architectural Enginnering, University of Colorado, Campus Box 428, Boulder, CO 80309-0428 (United States)]. E-mail: lneves@civil.uminho.pt

2006-06-15

In the last decade, it became clear that life-cycle cost analysis of existing civil infrastructure must be used to optimally manage the growing number of aging and deteriorating structures. The uncertainties associated with deteriorating structures require the use of probabilistic methods to properly evaluate their lifetime performance. In this paper, the deterioration and the effect of maintenance actions are analyzed considering the performance of existing structures characterized by lifetime functions. These functions allow, in a simple manner, the consideration of the effect of aging on the decrease of the probability of survival of a structure, as well as the effect of maintenance actions. Models for the effects of proactive and reactive preventive maintenance, and essential maintenance actions are presented. Since the probability of failure is different from zero during the entire service life of a deteriorating structure and depends strongly on the maintenance strategy, the cost of failure is included in this analysis. The failure of one component in a structure does not usually lead to failure of the structure and, as a result, the safety of existing structures must be analyzed using a system reliability framework. The optimization consists of minimizing the sum of the cumulative maintenance and expected failure cost during the prescribed time horizon. Two examples of application of the proposed methodology are presented. In the first example, the sum of the maintenance and failure costs of a bridge in Colorado is minimized considering essential maintenance only and a fixed minimum acceptable probability of failure. In the second example, the expected lifetime cost, including maintenance and expected failure costs, of a multi-girder bridge is minimized considering reactive preventive maintenance actions.

The use of lifetime functions in the optimization of interventions on existing bridges considering maintenance and failure costs

International Nuclear Information System (INIS)

Yang, Seung-Ie; Frangopol, Dan M.; Kawakami, Yoriko; Neves, Luis C.

2006-01-01

In the last decade, it became clear that life-cycle cost analysis of existing civil infrastructure must be used to optimally manage the growing number of aging and deteriorating structures. The uncertainties associated with deteriorating structures require the use of probabilistic methods to properly evaluate their lifetime performance. In this paper, the deterioration and the effect of maintenance actions are analyzed considering the performance of existing structures characterized by lifetime functions. These functions allow, in a simple manner, the consideration of the effect of aging on the decrease of the probability of survival of a structure, as well as the effect of maintenance actions. Models for the effects of proactive and reactive preventive maintenance, and essential maintenance actions are presented. Since the probability of failure is different from zero during the entire service life of a deteriorating structure and depends strongly on the maintenance strategy, the cost of failure is included in this analysis. The failure of one component in a structure does not usually lead to failure of the structure and, as a result, the safety of existing structures must be analyzed using a system reliability framework. The optimization consists of minimizing the sum of the cumulative maintenance and expected failure cost during the prescribed time horizon. Two examples of application of the proposed methodology are presented. In the first example, the sum of the maintenance and failure costs of a bridge in Colorado is minimized considering essential maintenance only and a fixed minimum acceptable probability of failure. In the second example, the expected lifetime cost, including maintenance and expected failure costs, of a multi-girder bridge is minimized considering reactive preventive maintenance actions

Lifetime Model of the Inverter-fed Motors Secondary Insulation by using a Design of Experiments

OpenAIRE

Lahoud, Nadine; Nguyen, Manh Quan; Maussion, Pascal; Malec, David; Mary, Dominique

2015-01-01

Numerous parameters (environmental conditions, material and equipments design) affect the ageing (and consequently the lifetime) of the Electrical Insulation System (EIS) of motors supplied by static converters. In order to find a modeling of the lifetime of such materials, accelerated tests have to be considered. The problem is that if we consider all the relevant parameters, these tests become costly and take a lot of time. Consequently the topic of this study i...

Modeling and optimization of membrane lifetime in dead-end ultra filtration

NARCIS (Netherlands)

Zondervan, E.; Roffel, B.

2008-01-01

In this paper, a membrane lifetime model is developed and experimentally validated. The lifetime model is based on the Weibull probability density function. The lifetime model can be used to determine an unambiguous characteristic membrane lifetime. Experimental results showed that membrane lifetime

Lifetime health effects and medical costs of integrated stroke services - a non-randomized controlled cluster-trial based life table approach

Directory of Open Access Journals (Sweden)

Dirks Maaike

2010-11-01

Full Text Available Abstract Background Economic evaluation of stroke services indicates that such services may lead to improved quality of life at affordable cost. The present study assesses lifetime health impact and cost consequences of stroke in an integrated service setting. Methods The EDISSE study is a prospective non-randomized controlled cluster trial that compared stroke services (n = 151 patients to usual care (n = 187 patients. Health status and cost trial-data were entered in multi-dimensional stroke life-tables. The tables distinguish four levels of disability which are defined by the modified Rankin scale. Quality-of-life scores (EuroQoL-5D, transition and survival probabilities are based on concurrent Dutch follow-up studies. Outcomes are quality-adjusted life years lived and lifetime medical cost by disability category. An economic analysis compares outcomes from a successful stroke service to usual care, by bootstrapping individual costs and effects data from patients in each arm. Results Lifetime costs and QALYs after stroke depend on age-of-onset of first-ever stroke. Lifetime QALYs after stroke are 2.42 (90% CI - 0.49 - 2.75 for male patients in usual care and 2.75 (-0.61; 6.26 for females. Lifetime costs for men in the usual care setting are €39,335 (15,951; 79,837 and €42,944 (14,081; 95,944 for women. A comparison with the stroke service results in an ICER of €11,685 saved per QALY gained (€14,211 and €7,745 for men and women respectively. This stroke service is with 90% certainty cost-effective. Conclusions Our analysis shows the potential of large health benefits and cost savings of stroke services, taking a lifetime perspective, also in other European settings.

Design of Boiler Welding for Improvement of Lifetime and Cost Control

OpenAIRE

Thong-On, Atcharawadi; Boonruang, Chatdanai

2016-01-01

Fe-2.25Cr-1Mo a widely used material for headers and steam tubes of boilers. Welding of steam tube to header is required for production of boiler. Heat affected zone of the weld can have poor mechanical properties and poor corrosion behavior leading to weld failure. The cost of material used for steam tube and header of boiler should be controlled. This study propose a new materials design for boiler welding to improve the lifetime and cost control, using tungsten inert gas (TIG) welding of F...

Remaining lifetime modeling using State-of-Health estimation

Science.gov (United States)

Beganovic, Nejra; Söffker, Dirk

2017-08-01

Technical systems and system's components undergo gradual degradation over time. Continuous degradation occurred in system is reflected in decreased system's reliability and unavoidably lead to a system failure. Therefore, continuous evaluation of State-of-Health (SoH) is inevitable to provide at least predefined lifetime of the system defined by manufacturer, or even better, to extend the lifetime given by manufacturer. However, precondition for lifetime extension is accurate estimation of SoH as well as the estimation and prediction of Remaining Useful Lifetime (RUL). For this purpose, lifetime models describing the relation between system/component degradation and consumed lifetime have to be established. In this contribution modeling and selection of suitable lifetime models from database based on current SoH conditions are discussed. Main contribution of this paper is the development of new modeling strategies capable to describe complex relations between measurable system variables, related system degradation, and RUL. Two approaches with accompanying advantages and disadvantages are introduced and compared. Both approaches are capable to model stochastic aging processes of a system by simultaneous adaption of RUL models to current SoH. The first approach requires a priori knowledge about aging processes in the system and accurate estimation of SoH. An estimation of SoH here is conditioned by tracking actual accumulated damage into the system, so that particular model parameters are defined according to a priori known assumptions about system's aging. Prediction accuracy in this case is highly dependent on accurate estimation of SoH but includes high number of degrees of freedom. The second approach in this contribution does not require a priori knowledge about system's aging as particular model parameters are defined in accordance to multi-objective optimization procedure. Prediction accuracy of this model does not highly depend on estimated SoH. This model

Lifetime-management and lifetime-extension at PAKS nuclear power plant

International Nuclear Information System (INIS)

Katona, Tamas; Ratkai, Sandor; Janosi, Agnes Biro

2002-01-01

core might be necessary with 50% probability. Annealing is not a cost critical method and it has been successfully applied in the practice of VVER plants (i.e. Finland and Slovakia). The study indicates that the steam generators are very important and critical equipment at VVER/440/213 type units. Stress corrosion cracking of heat-transfer tubes shall be considered also in case of steam generators. Considering the effects of already implemented measures, e.g. main turbine-condenser replacement, copper removing, protecting the secondary side of steam generators, replacement of steam generators can be excluded also in case of 50 years of operation. However, local corrosion effects appearing on the secondary side shall be monitored even in case of high PH water regime, transport of erosion products into the steam generator shall be minimised, for example by means of correct selection of the structural materials during replacement of high pressure preheaters. Business model of the lifetime extension covered incomes, expenses and financing. The costs of plant life management and lifetime extension have been estimated conservatively. The market conditions, including liberalisation of the electrical power market have been taken into account. The business analysis shows that the plant lifetime extension is a reasonable business decision. Based on the results of the feasibility study and the public acceptance of extended operation NPP Paks launched a project to elaborate on the plant lifetime management programme and preparation of the necessary licence renewal. The current ageing-management programme of the Paks NPP shall be reviewed and extended to the required scope of SSC (passive long living items). Programme for maintaining the environmental qualification of equipment has to be elaborated on and implemented. Simultaneous to the preparation of the license renewal new requirements shall be implemented in the field of maintenance, also. The plant lifetime extension might

Lifetime Economic Burden of Rape Among U.S. Adults.

Science.gov (United States)

Peterson, Cora; DeGue, Sarah; Florence, Curtis; Lokey, Colby N

2017-06-01

This study estimated the per-victim U.S. lifetime cost of rape. Data from previous studies was combined with current administrative data and 2011 U.S. National Intimate Partner and Sexual Violence Survey data in a mathematical model. Rape was defined as any lifetime completed or attempted forced penetration or alcohol- or drug-facilitated penetration, measured among adults not currently institutionalized. Costs included attributable impaired health, lost productivity, and criminal justice costs from the societal perspective. Average age at first rape was assumed to be 18 years. Future costs were discounted by 3%. The main outcome measures were the average per-victim (female and male) and total population discounted lifetime cost of rape. Secondary outcome measures were marginal outcome probabilities among victims (e.g., suicide attempt) and perpetrators (e.g., incarceration) and associated costs. Analysis was conducted in 2016. The estimated lifetime cost of rape was $122,461 per victim, or a population economic burden of nearly $3.1 trillion (2014 U.S. dollars) over victims' lifetimes, based on data indicating >25 million U.S. adults have been raped. This estimate included $1.2 trillion (39% of total) in medical costs; $1.6 trillion (52%) in lost work productivity among victims and perpetrators; $234 billion (8%) in criminal justice activities; and $36 billion (1%) in other costs, including victim property loss or damage. Government sources pay an estimated $1 trillion (32%) of the lifetime economic burden. Preventing sexual violence could avoid substantial costs for victims, perpetrators, healthcare payers, employers, and government payers. These findings can inform evaluations of interventions to reduce sexual violence. Published by Elsevier Inc.

Lifetime modelling of lead acid batteries

DEFF Research Database (Denmark)

Bindner, H.; Cronin, T.; Lundsager, P.

2005-01-01

The performance and lifetime of energy storage in batteries are an important part of many renewable based energy systems. Not only do batteries impact on the system performance but they are also a significant expenditure when considering the whole lifecycle costs. Poor prediction of lifetime can......, therefore, lead to uncertainty in the viability of the system in the long term. This report details the work undertaken to investigate and develop two different battery life prediction methodologies withspecific reference to their use in hybrid renewable energy systems. Alongside this, results from battery...... tests designed to exercise batteries in similar modes to those that they experience in hybrid systems have also been analysed. These have yieldedbattery specific parameters for use in the prediction software and the first results in the validation process of the software are also given. This work has...

Statistical Models and Methods for Lifetime Data

CERN Document Server

Lawless, Jerald F

2011-01-01

Praise for the First Edition"An indispensable addition to any serious collection on lifetime data analysis and . . . a valuable contribution to the statistical literature. Highly recommended . . ."-Choice"This is an important book, which will appeal to statisticians working on survival analysis problems."-Biometrics"A thorough, unified treatment of statistical models and methods used in the analysis of lifetime data . . . this is a highly competent and agreeable statistical textbook."-Statistics in MedicineThe statistical analysis of lifetime or response time data is a key tool in engineering,

Lifetime cost effectiveness of a through-school nutrition and physical programme: Project Energize.

Science.gov (United States)

Rush, Elaine; Obolonkin, Victor; McLennan, Stephanie; Graham, David; Harris, James D; Mernagh, Paul; Weston, Adéle R

2014-01-01

Project Energize, a multicomponent through-school physical activity and nutrition programme, is delivered to all primary school children in the Waikato region. The programme aim is to improve the overall health and reduce the rate of weight gain of all Waikato primary school children. An existing economic model was used to extrapolate the programme effects, initial costs, lifetime health treatment cost structures, quality-adjusted-life-years gained and increased life expectancy to the general and Māori child population of New Zealand. In March 2011, a sample of 2474 younger (7.58 ± 0.57 years, mean ± SD) and 2330 older (10.30 ± 0.51 years) children (36% Māori) attending Energize schools had body mass index measured and compared using mixed effect modelling with unEnergized comparison children from 2004 and 2006 from the same region. In 2011 the median body mass index reduction compared with the comparison younger children was -0.504 (90% CI -0.435 to -0.663) kg/m(2) and in the older children -0.551 (-0.456 to -0.789) kg/m(2). In 2010 there were 42,067 children attending Energize schools and in the same year NZ$1,891,175 was spent to deliver the programme; a cost of $44.96/child/year. Compared to the comparison children the increment in cost/quality-adjusted-life-year gained was $30,438 for the younger and $24,690 for the older children, and lower for Māori (younger $28,241, older $22,151) and for the middle socioeconomic status schools ($23,211, $17,891). Project Energize would improve quality and length of life and when compared with other obesity prevention programmes previously assessed with this model, it would be relatively cost-effective from the health treatment payer's perspective.

Two-Year and Lifetime Cost-Effectiveness of Intensity Modulated Radiation Therapy Versus 3-Dimensional Conformal Radiation Therapy for Head-and-Neck Cancer

Energy Technology Data Exchange (ETDEWEB)

Kohler, Racquel E. [Department of Health Policy and Management, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina (United States); Sheets, Nathan C. [Department of Radiation Oncology, University of North Carolina Hospitals, Chapel Hill, North Carolina (United States); Wheeler, Stephanie B. [Department of Health Policy and Management, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina (United States); Nutting, Chris [Royal Marsden Hospital, London, United Kindom (United Kingdom); Hall, Emma [Clinical Trials and Statistics Unit, Division of Clinical Studies, Institute of Cancer Research, London (United Kingdom); Chera, Bhishamjit S., E-mail: bchera@med.unc.edu [Department of Radiation Oncology, University of North Carolina Hospitals, Chapel Hill, North Carolina (United States)

2013-11-15

Purpose: To assess the cost-effectiveness of intensity modulated radiation therapy (IMRT) versus 3-dimensional conformal radiation therapy (3D-CRT) in the treatment of head-and neck-cancer (HNC). Methods and Materials: We used a Markov model to simulate radiation therapy-induced xerostomia and dysphagia in a hypothetical cohort of 65-year-old HNC patients. Model input parameters were derived from PARSPORT (CRUK/03/005) patient-level trial data and quality-of-life and Medicare cost data from published literature. We calculated average incremental cost-effectiveness ratios (ICERs) from the US health care perspective as cost per quality-adjusted life-year (QALY) gained and compared our ICERs with current cost-effectiveness standards whereby treatment comparators less than $50,000 per QALY gained are considered cost-effective. Results: In the first 2 years after initial treatment, IMRT is not cost-effective compared with 3D-CRT, given an average ICER of $101,100 per QALY gained. However, over 15 years (remaining lifetime on the basis of average life expectancy of a 65-year-old), IMRT is more cost-effective at $34,523 per QALY gained. Conclusion: Although HNC patients receiving IMRT will likely experience reduced xerostomia and dysphagia symptoms, the small quality-of-life benefit associated with IMRT is not cost-effective in the short term but may be cost-effective over a patient's lifetime, assuming benefits persist over time and patients are healthy and likely to live for a sustained period. Additional data quantifying the long-term benefits of IMRT, however, are needed.

Estimation of Life-Year Loss and Lifetime Costs for Different Stages of Colon Adenocarcinoma in Taiwan.

Science.gov (United States)

Chen, Po-Chuan; Lee, Jenq-Chang; Wang, Jung-Der

2015-01-01

Life-expectancy of colon cancer patients cannot be accurately answered due to the lack of both large datasets and long-term follow-ups, which impedes accurate estimation of lifetime cost to treat colon cancer patients. In this study, we applied a method to estimate life-expectancy of colon cancer patients in Taiwan and calculate the lifetime costs by different stages and age groups. A total of 17,526 cases with pathologically verified colon adenocarcinoma between 2002 and 2009 were extracted from Taiwan Cancer Registry database for analysis. All patients were followed-up until the end of 2011. Life-expectancy, expected-years-of-life-lost and lifetime costs were estimated, using a semi-parametric survival extrapolation method and borrowing information from life tables of vital statistics. Patients with more advanced stages of colon cancer were generally younger and less co-morbid with major chronic diseases than those with stages I and II. The LE of stage I was not significantly different from that of the age- and sex-matched general population, whereas those of stages II, III, and IV colon cancer patients after diagnosis were 16.57 ± 0.07, 13.35 ± 0.07, and 4.05 ± 0.05 years, respectively; the corresponding expected-years-of-life-lost were 1.28 ± 0.07, 5.93 ± 0.07 and 16.42 ± 0.06 years, significantly shorter than the general population after accounting for lead time bias. Besides, the lifetime cost of managing stage II colon cancer patients would be US $8,416 ± 1939, 14,334 ± 1,755, and 21,837 ± 1,698, respectively, indicating a big saving for early diagnosis and treatment after stratification for age and sex. Treating colon cancer at younger age and earlier stage saves more life-years and healthcare costs. Future studies are indicated to apply these quantitative results into the cost-effectiveness evaluation of screening program for colon cancers.

Lifetime-Aware Cloud Data Centers: Models and Performance Evaluation

Directory of Open Access Journals (Sweden)

Luca Chiaraviglio

2016-06-01

Full Text Available We present a model to evaluate the server lifetime in cloud data centers (DCs. In particular, when the server power level is decreased, the failure rate tends to be reduced as a consequence of the limited number of components powered on. However, the variation between the different power states triggers a failure rate increase. We therefore consider these two effects in a server lifetime model, subject to an energy-aware management policy. We then evaluate our model in a realistic case study. Our results show that the impact on the server lifetime is far from negligible. As a consequence, we argue that a lifetime-aware approach should be pursued to decide how and when to apply a power state change to a server.

Cost effectiveness analysis comparing repetitive transcranial magnetic stimulation to antidepressant medications after a first treatment failure for major depressive disorder in newly diagnosed patients - A lifetime analysis.

Science.gov (United States)

Voigt, Jeffrey; Carpenter, Linda; Leuchter, Andrew

2017-01-01

Repetitive Transcranial Magnetic Stimulation (rTMS) commonly is used for the treatment of Major Depressive Disorder (MDD) after patients have failed to benefit from trials of multiple antidepressant medications. No analysis to date has examined the cost-effectiveness of rTMS used earlier in the course of treatment and over a patients' lifetime. We used lifetime Markov simulation modeling to compare the direct costs and quality adjusted life years (QALYs) of rTMS and medication therapy in patients with newly diagnosed MDD (ages 20-59) who had failed to benefit from one pharmacotherapy trial. Patients' life expectancies, rates of response and remission, and quality of life outcomes were derived from the literature, and treatment costs were based upon published Medicare reimbursement data. Baseline costs, aggregate per year quality of life assessments (QALYs), Monte Carlo simulation, tornado analysis, assessment of dominance, and one way sensitivity analysis were also performed. The discount rate applied was 3%. Lifetime direct treatment costs, and QALYs identified rTMS as the dominant therapy compared to antidepressant medications (i.e., lower costs with better outcomes) in all age ranges, with costs/improved QALYs ranging from $2,952/0.32 (older patients) to $11,140/0.43 (younger patients). One-way sensitivity analysis demonstrated that the model was most sensitive to the input variables of cost per rTMS session, monthly prescription drug cost, and the number of rTMS sessions per year. rTMS was identified as the dominant therapy compared to antidepressant medication trials over the life of the patient across the lifespan of adults with MDD, given current costs of treatment. These models support the use of rTMS after a single failed antidepressant medication trial versus further attempts at medication treatment in adults with MDD.

Cost effectiveness analysis comparing repetitive transcranial magnetic stimulation to antidepressant medications after a first treatment failure for major depressive disorder in newly diagnosed patients - A lifetime analysis.

Directory of Open Access Journals (Sweden)

Jeffrey Voigt

Full Text Available Repetitive Transcranial Magnetic Stimulation (rTMS commonly is used for the treatment of Major Depressive Disorder (MDD after patients have failed to benefit from trials of multiple antidepressant medications. No analysis to date has examined the cost-effectiveness of rTMS used earlier in the course of treatment and over a patients' lifetime.We used lifetime Markov simulation modeling to compare the direct costs and quality adjusted life years (QALYs of rTMS and medication therapy in patients with newly diagnosed MDD (ages 20-59 who had failed to benefit from one pharmacotherapy trial. Patients' life expectancies, rates of response and remission, and quality of life outcomes were derived from the literature, and treatment costs were based upon published Medicare reimbursement data. Baseline costs, aggregate per year quality of life assessments (QALYs, Monte Carlo simulation, tornado analysis, assessment of dominance, and one way sensitivity analysis were also performed. The discount rate applied was 3%.Lifetime direct treatment costs, and QALYs identified rTMS as the dominant therapy compared to antidepressant medications (i.e., lower costs with better outcomes in all age ranges, with costs/improved QALYs ranging from $2,952/0.32 (older patients to $11,140/0.43 (younger patients. One-way sensitivity analysis demonstrated that the model was most sensitive to the input variables of cost per rTMS session, monthly prescription drug cost, and the number of rTMS sessions per year.rTMS was identified as the dominant therapy compared to antidepressant medication trials over the life of the patient across the lifespan of adults with MDD, given current costs of treatment. These models support the use of rTMS after a single failed antidepressant medication trial versus further attempts at medication treatment in adults with MDD.

Empirical membrane lifetime model for heavy duty fuel cell systems

Science.gov (United States)

Macauley, Natalia; Watson, Mark; Lauritzen, Michael; Knights, Shanna; Wang, G. Gary; Kjeang, Erik

2016-12-01

Heavy duty fuel cells used in transportation system applications such as transit buses expose the fuel cell membranes to conditions that can lead to lifetime-limiting membrane failure via combined chemical and mechanical degradation. Highly durable membranes and reliable predictive models are therefore needed in order to achieve the ultimate heavy duty fuel cell lifetime target of 25,000 h. In the present work, an empirical membrane lifetime model was developed based on laboratory data from a suite of accelerated membrane durability tests. The model considers the effects of cell voltage, temperature, oxygen concentration, humidity cycling, humidity level, and platinum in the membrane using inverse power law and exponential relationships within the framework of a general log-linear Weibull life-stress statistical distribution. The obtained model is capable of extrapolating the membrane lifetime from accelerated test conditions to use level conditions during field operation. Based on typical conditions for the Whistler, British Columbia fuel cell transit bus fleet, the model predicts a stack lifetime of 17,500 h and a membrane leak initiation time of 9200 h. Validation performed with the aid of a field operated stack confirmed the initial goal of the model to predict membrane lifetime within 20% of the actual operating time.

Costs and expected gain in lifetime health from intensive care versus general ward care of 30,712 individual patients: a distribution-weighted cost-effectiveness analysis.

Science.gov (United States)

Lindemark, Frode; Haaland, Øystein A; Kvåle, Reidar; Flaatten, Hans; Norheim, Ole F; Johansson, Kjell A

2017-08-21

Clinicians, hospital managers, policy makers, and researchers are concerned about high costs, increased demand, and variation in priorities in the intensive care unit (ICU). The objectives of this modelling study are to describe the extra costs and expected health gains associated with admission to the ICU versus the general ward for 30,712 patients and the variation in cost-effectiveness estimates among subgroups and individuals, and to perform a distribution-weighted economic evaluation incorporating extra weighting to patients with high severity of disease. We used a decision-analytic model that estimates the incremental cost per quality-adjusted life year (QALY) gained (ICER) from ICU admission compared with general ward care using Norwegian registry data from 2008 to 2010. We assigned increasing weights to health gains for those with higher severity of disease, defined as less expected lifetime health if not admitted. The study has inherent uncertainty of findings because a randomized clinical trial comparing patients admitted or rejected to the ICU has never been performed. Uncertainty is explored in probabilistic sensitivity analysis. The mean cost-effectiveness of ICU admission versus ward care was €11,600/QALY, with 1.6 QALYs gained and an incremental cost of €18,700 per patient. The probability (p) of cost-effectiveness was 95% at a threshold of €22,000/QALY. The mean ICER for medical admissions was €10,700/QALY (p = 97%), €12,300/QALY (p = 93%) for admissions after acute surgery, and €14,700/QALY (p = 84%) after planned surgery. For individualized ICERs, there was a 50% probability that ICU admission was cost-effective for 85% of the patients at a threshold of €64,000/QALY, leaving 15% of the admissions not cost-effective. In the distributional evaluation, 8% of all patients had distribution-weighted ICERs (higher weights to gains for more severe conditions) above €64,000/QALY. High-severity admissions gained the most, and were more

Lifetime, money and cost-benefit analysis

International Nuclear Information System (INIS)

Bengtsson, G.

1984-01-01

The paper describes briefly many methods for explicit or implicit valuation of the loss of lifetime expectancy due to radiation exposures or other hazards. The health gain from investment in protection is compared with the health gain from a general increase in wealth. It is concluded that in many instances lifetime is valued at 1 to 10 times the gross national product produced in this time. This seems to be reasonable for rich countries whereas it may be questionable for poorer countries. Here, any investment that raises the level of living of the poorer segment of the population may have a greater effect on life expectancy. (author)

Long-term economic benefits attributed to IVF-conceived children: a lifetime tax calculation.

Science.gov (United States)

Connolly, Mark P; Pollard, Michael S; Hoorens, Stijn; Kaplan, Brian R; Oskowitz, Selwyn P; Silber, Sherman J

2008-09-01

To evaluate whether lifetime future net tax revenues from an in vitro fertilization (IVF)-conceived child are substantial enough to warrant public subsidy relative to the mean IVF treatment costs required to obtain 1 live birth. Mathematical generational accounting model. The model estimates direct financial interactions between the IVF-conceived child and the government during the child's projected lifetime. In the model, we accrue IVF costs required to conceive the child to the government, and then we estimate future net tax revenue to the federal and state governments from this individual, offset by direct financial transfers from the government (eg, child allowances, education, Medicare, and Social Security). We discount lifetime costs and gross tax payments at Treasury Department rates to establish the present value of investing in IVF. We applied US Congressional Budget Office projected changes in tax rates over the course of the model. An IVF-conceived child, average in every respect (eg, future earnings, healthcare consumption, and life expectancy), represents a net positive return to the government. Based on an average employed individual born in 2005, the projected net lifetime tax contribution is US $606,200. Taking into consideration IVF costs and all direct financial interactions, the net present value is US $155,870. Lifetime net taxes paid from a child relative to the child's initial IVF investment represent a 700% net return to the government in discounted US dollars from fully employed individuals. This suggests that removing barriers to IVF would have positive tax benefits for the government, notwithstanding its beneficial effect on overall economic growth.

Energy Savings Lifetimes and Persistence

Energy Technology Data Exchange (ETDEWEB)

Hoffman, Ian M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Schiller, Steven R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Todd, Annika [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Billingsley, Megan A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Goldman, Charles A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Schwartz, Lisa C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2016-02-01

This technical brief explains the concepts of energy savings lifetimes and savings persistence and discusses how program administrators use these factors to calculate savings for efficiency measures, programs and portfolios. Savings lifetime is the length of time that one or more energy efficiency measures or activities save energy, and savings persistence is the change in savings throughout the functional life of a given efficiency measure or activity. Savings lifetimes are essential for assessing the lifecycle benefits and cost effectiveness of efficiency activities and for forecasting loads in resource planning. The brief also provides estimates of savings lifetimes derived from a national collection of costs and savings for electric efficiency programs and portfolios.

Filter replacement lifetime prediction

Science.gov (United States)

Hamann, Hendrik F.; Klein, Levente I.; Manzer, Dennis G.; Marianno, Fernando J.

2017-10-25

Methods and systems for predicting a filter lifetime include building a filter effectiveness history based on contaminant sensor information associated with a filter; determining a rate of filter consumption with a processor based on the filter effectiveness history; and determining a remaining filter lifetime based on the determined rate of filter consumption. Methods and systems for increasing filter economy include measuring contaminants in an internal and an external environment; determining a cost of a corrosion rate increase if unfiltered external air intake is increased for cooling; determining a cost of increased air pressure to filter external air; and if the cost of filtering external air exceeds the cost of the corrosion rate increase, increasing an intake of unfiltered external air.

Decision analytic cost-effectiveness model to compare prostate cryotherapy to androgen deprivation therapy for treatment of radiation recurrent prostate cancer

Science.gov (United States)

Boyd, Kathleen A; Jones, Rob J; Paul, Jim; Birrell, Fiona; Briggs, Andrew H; Leung, Hing Y

2015-01-01

Objective To determine the cost-effectiveness of salvage cryotherapy (SC) in men with radiation recurrent prostate cancer (RRPC). Design Cost-utility analysis using decision analytic modelling by a Markov model. Setting and methods Compared SC and androgen deprivation therapy (ADT) in a cohort of patients with RRPC (biopsy proven local recurrence, no evidence of metastatic disease). A literature review captured published data to inform the decision model, and resource use data were from the Scottish Prostate Cryotherapy Service. The model was run in monthly cycles for RRPC men, mean age of 70 years. The model was run over the patient lifetime, to assess changes in patient health states and the associated quality of life, survival and cost impacts. Results are reported in terms of the discounted incremental costs and discounted incremental quality-adjusted life years (QALYs) gained between the 2 alternative interventions. Probabilistic sensitivity analysis used a 10 000 iteration Monte Carlo simulation. Results SC has a high upfront treatment cost, but delays the ongoing monthly cost of ADT. SC is the dominant strategy over the patient lifetime; it is more effective with an incremental 0.56 QALY gain (95% CI 0.28 to 0.87), and less costly with a reduced lifetime cost of £29 719 (€37 619) (95% CI −51 985 to −9243). For a ceiling ratio of £30 000, SC has a 100% probability to be cost-effective. The cost neutral point was at 3.5 years, when the upfront cost of SC (plus any subsequent cumulative cost of side effects and ADT) equates the cumulative cost in the ADT arm. Limitations of our model may arise from its insensitivity to parameter or structural uncertainty. Conclusions The platform for SC versus ADT cost-effective analysis can be employed to evaluate other treatment modalities or strategies in RRPC. SC is the dominant strategy, costing less over a patient's lifetime with improvements in QALYs. Trial registration number This economic analysis

Prediction of the lifetime productive and reproductive performance of Holstein cows managed for different lactation durations, using a model of lifetime nutrient partitioning

DEFF Research Database (Denmark)

Gaillard, Charlotte; Martin, O; Blavy, P

2016-01-01

The GARUNS model is a lifetime performance model taking into account the changing physiological priorities of an animal during its life and through repeated reproduction cycles. This dynamic and stochastic model has been previously used to predict the productive and reproductive performance...... of various genotypes of cows across feeding systems. In the present paper, we used this model to predict the lifetime productive and reproductive performance of Holstein cows for different lactation durations, with the aim of determining the lifetime scenario that optimizes cows' performance defined...... by lifetime efficiency (ratio of total milk energy yield to total energy intake) and pregnancy rate. To evaluate the model, data from a 16-mo extended lactation experiment on Holstein cows were used. Generally, the model could consistently fit body weight, milk yield, and milk components of these cows...

Deployment-based lifetime optimization model for homogeneous Wireless Sensor Network under retransmission.

Science.gov (United States)

Li, Ruiying; Liu, Xiaoxi; Xie, Wei; Huang, Ning

2014-12-10

Sensor-deployment-based lifetime optimization is one of the most effective methods used to prolong the lifetime of Wireless Sensor Network (WSN) by reducing the distance-sensitive energy consumption. In this paper, data retransmission, a major consumption factor that is usually neglected in the previous work, is considered. For a homogeneous WSN, monitoring a circular target area with a centered base station, a sensor deployment model based on regular hexagonal grids is analyzed. To maximize the WSN lifetime, optimization models for both uniform and non-uniform deployment schemes are proposed by constraining on coverage, connectivity and success transmission rate. Based on the data transmission analysis in a data gathering cycle, the WSN lifetime in the model can be obtained through quantifying the energy consumption at each sensor location. The results of case studies show that it is meaningful to consider data retransmission in the lifetime optimization. In particular, our investigations indicate that, with the same lifetime requirement, the number of sensors needed in a non-uniform topology is much less than that in a uniform one. Finally, compared with a random scheme, simulation results further verify the advantage of our deployment model.

Computer programs for capital cost estimation, lifetime economic performance simulation, and computation of cost indexes for laser fusion and other advanced technology facilities

International Nuclear Information System (INIS)

Pendergrass, J.H.

1978-01-01

Three FORTRAN programs, CAPITAL, VENTURE, and INDEXER, have been developed to automate computations used in assessing the economic viability of proposed or conceptual laser fusion and other advanced-technology facilities, as well as conventional projects. The types of calculations performed by these programs are, respectively, capital cost estimation, lifetime economic performance simulation, and computation of cost indexes. The codes permit these three topics to be addressed with considerable sophistication commensurate with user requirements and available data

Review of selected cost drivers for decisions on continued operation of older nuclear reactors. Safety upgrades, lifetime extension, decommissioning

International Nuclear Information System (INIS)

1999-05-01

Lately, the approach to the operation of relatively old NPPs has become an important issue for the nuclear industry for several reasons. First, a large part of operating NPPs will reach the planned end of their lives relatively soon. Replacing these capacities can involve significant investment for the concerned countries and utilities. Second, many operating NPPs while about 30 years old are still in very good condition. Their continued safe operation appears possible and may bring about essential economic gains. Finally, with the costs of new NPPs being rather high at present, continued operation of existing plants and eventually their lifetime extension are viable options for supporting the nuclear share in power generation. This is becoming especially important in view of the growing attention to the issue of global warming and the role of nuclear energy in greenhouse gas mitigation. This report is a review of information related to three cost categories that are part of such cost-benefit analysis: costs of safety upgrades for continued operation of a nuclear unit, costs of lifetime extension and costs of decommissioning. It can serve as a useful reference source for experts and decision makers involved in the economics of operating NPPs

Preventative maintenance cycle of contact switches for nuclear power plants based on lifetime assessment and economic analysis

International Nuclear Information System (INIS)

Shi Jie

2010-01-01

An approach to determine the preventive maintenance cycle was proposed in consideration of the lifetime, optimal cost and economy. Two parameters Weibull distribution was used to calculate the lifetime of contact switch. The block replacement model and age replacement model were built with the objective of optimal cost, and the preventive replacement cycle was accounted. Eight proposals for preventive replacement cycle were given. Economy model was applied to assess those proposals and the optimal proposal was confirmed. (authors)

Calculating excess lifetime risk in relative risk models

International Nuclear Information System (INIS)

Vaeth, M.; Pierce, D.A.

1990-01-01

When assessing the impact of radiation exposure it is common practice to present the final conclusions in terms of excess lifetime cancer risk in a population exposed to a given dose. The present investigation is mainly a methodological study focusing on some of the major issues and uncertainties involved in calculating such excess lifetime risks and related risk projection methods. The age-constant relative risk model used in the recent analyses of the cancer mortality that was observed in the follow-up of the cohort of A-bomb survivors in Hiroshima and Nagasaki is used to describe the effect of the exposure on the cancer mortality. In this type of model the excess relative risk is constant in age-at-risk, but depends on the age-at-exposure. Calculation of excess lifetime risks usually requires rather complicated life-table computations. In this paper we propose a simple approximation to the excess lifetime risk; the validity of the approximation for low levels of exposure is justified empirically as well as theoretically. This approximation provides important guidance in understanding the influence of the various factors involved in risk projections. Among the further topics considered are the influence of a latent period, the additional problems involved in calculations of site-specific excess lifetime cancer risks, the consequences of a leveling off or a plateau in the excess relative risk, and the uncertainties involved in transferring results from one population to another. The main part of this study relates to the situation with a single, instantaneous exposure, but a brief discussion is also given of the problem with a continuous exposure at a low-dose rate

Model improves oil field operating cost estimates

International Nuclear Information System (INIS)

Glaeser, J.L.

1996-01-01

A detailed operating cost model that forecasts operating cost profiles toward the end of a field's life should be constructed for testing depletion strategies and plans for major oil fields. Developing a good understanding of future operating cost trends is important. Incorrectly forecasting the trend can result in bad decision making regarding investments and reservoir operating strategies. Recent projects show that significant operating expense reductions can be made in the latter stages o field depletion without significantly reducing the expected ultimate recoverable reserves. Predicting future operating cost trends is especially important for operators who are currently producing a field and must forecast the economic limit of the property. For reasons presented in this article, it is usually not correct to either assume that operating expense stays fixed in dollar terms throughout the lifetime of a field, nor is it correct to assume that operating costs stay fixed on a dollar per barrel basis

Lifetime of {sup 44}Ti as probe for supernova models

Energy Technology Data Exchange (ETDEWEB)

Goerres, J; Meissner, J; Schatz, H; Stech, E; Tischhauser, P; Wiescher, M [Univ. of Notre Dame, Notre Dame, IN (United States); Bazin, D; Harkewicz, R; Hellstroem, M; Sherrill, B; Steiner, M [Michigan State Univ., East Lansing, MI (United States); Boyd, R N [Ohio State Univ., Columbus, OH (United States); Buchmann, L [TRIUMF, Vancouver, BC (Canada); Hartmann, D H [Clemson Univ., Clemson, SC (United States); Hinnefeld, J D [Indiana Univ. South Bend, South Bend, IN (United States)

1998-06-01

The recent observation of {sup 44}Ti radioactivity in the supernova remnant Cassiopeia A with the Compton Gamma Ray Observatory allows the determination of the absolute amount of {sup 44}Ti. This provides a test for current supernova models. The main uncertainty is the lifetime of {sup 44}Ti. We report a new measurement of the lifetime of {sup 44}Ti applying a novel technique. A mixed radioactive beam containing {sup 44}Ti as well as {sup 22}Na was implanted and the resulting {gamma}-activity was measured. This allowed the determination of the lifetime of {sup 44}Ti relative to the lifetime of {sup 22}Na, {tau} = (87.0 {+-} 1.9) y. With this lifetime, the {sup 44}Ti abundance agrees with theoretical predictions within the remaining observational uncertainties. (orig.)

Profit-Based Model Selection for Customer Retention Using Individual Customer Lifetime Values.

Science.gov (United States)

Óskarsdóttir, María; Baesens, Bart; Vanthienen, Jan

2018-03-01

The goal of customer retention campaigns, by design, is to add value and enhance the operational efficiency of businesses. For organizations that strive to retain their customers in saturated, and sometimes fast moving, markets such as the telecommunication and banking industries, implementing customer churn prediction models that perform well and in accordance with the business goals is vital. The expected maximum profit (EMP) measure is tailored toward this problem by taking into account the costs and benefits of a retention campaign and estimating its worth for the organization. Unfortunately, the measure assumes fixed and equal customer lifetime value (CLV) for all customers, which has been shown to not correspond well with reality. In this article, we extend the EMP measure to take into account the variability in the lifetime values of customers, thereby basing it on individual characteristics. We demonstrate how to incorporate the heterogeneity of CLVs when CLVs are known, when their prior distribution is known, and when neither is known. By taking into account individual CLVs, our proposed approach of measuring model performance gives novel insights when deciding on a customer retention campaign. The method is dependent on the characteristics of the customer base as is compliant with modern business analytics and accommodates the data-driven culture that has manifested itself within organizations.

Cost-effectiveness of a school-based health promotion program in Canada: A life-course modeling approach.

Science.gov (United States)

Ekwaru, John Paul; Ohinmaa, Arto; Tran, Bach Xuan; Setayeshgar, Solmaz; Johnson, Jeffrey A; Veugelers, Paul J

2017-01-01

The Alberta Project Promoting active Living and healthy Eating in Schools (APPLE Schools) has been recognized as a "best practice" in preventing childhood obesity. To inform decision making on the economic implications of APPLE Schools and to justify investment, we evaluated the project's cost-effectiveness following a life-course approach. We developed a state transition model for the lifetime progression of body weight status comparing elementary school students attending APPLE Schools and control schools. This model quantified the lifetime impact of APPLE Schools in terms of prevention of excess body weight, chronic disease and improved quality-adjusted life years (QALY), from a school system's cost perspective. Both costs and health outcomes were discounted to their present value using 3% discount rate. The incremental cost-effectiveness ratio(ICER) of APPLE schools was CA$33,421 per QALY gained, and CA$1,555, CA$1,709 and CA$14,218 per prevented person years of excess weight, obesity and chronic disease, respectively. These estimates show that APPLE Schools is cost effective at a threshold of ICER Schools was cost effective more than 64% of the time per QALY gained, when using a threshold of ICERSchool-based health promotion, such as APPLE Schools is a cost-effective intervention for obesity prevention and reduction of chronic disease risk over the lifetime. Expanding the coverage and allocating resources towards school-based programs like the APPLE Schools program, is likely to reduce the public health burden of obesity and chronic diseases.

SIRTF thermal design modifications to increase lifetime

Science.gov (United States)

Petrick, S. W.

1993-01-01

An effort was made to increase the predicted lifetime of the SIRTF dewar by lowering the exterior shell temperature, increasing the radiated energy from the vapor cooled shields and reconfiguring the vapor cooled shields. The lifetime increases can be used to increase the scientific return from the mission and as a trade-off against mass and cost. This paper describes the configurations studied, the steady state thermal model used, the analytical methods and the results of the analysis. Much of the heat input to the outside dewar shell is radiative heat transfer from the solar panel. To lower the shell temperature, radiative cooled shields were placed between the solar panel and the dewar shell and between the bus and the dewar shell. Analysis showed that placing a radiator on the outer vapor cooled shield had a significant effect on lifetime. Lengthening the distance between the outer shell and the point where the vapor cooled shields are attached to the support straps also improved lifetime.

Lifetime modelling of lead acid batteries

Energy Technology Data Exchange (ETDEWEB)

Bindner, H.; Cronin, T.; Lundsager, P.

2005-04-01

The performance and lifetime of energy storage in batteries are an important part of many renewable based energy systems. Not only do batteries impact on the system performance but they are also a significant expenditure when considering the whole life cycle costs. Poor prediction of lifetime can, therefore, lead to uncertainty in the viability of the system in the long term. This report details the work undertaken to investigate and develop two different battery life prediction methodologies with specific reference to their use in hybrid renewable energy systems. Alongside this, results from battery tests designed to exercise batteries in similar modes to those that they experience in hybrid systems have also been analysed. These have yielded battery specific parameters for use in the prediction software and the first results in the validation process of the software are also given. This work has been part of the European Union Benchmarking research project (ENK6-CT-2001-80576), funded by the European Union, the United States and Australian governments together with other European states and other public and private financing bodies. The project has concentrated on lead acid batteries as this technology is the most commonly used. Through this work the project partner institutions have intended to provide useful tools to improve the design capabilities of organizations, private and public, in remote power systems. (au)

Cost-effectiveness of an HPV self-collection campaign in Uganda: comparing models for delivery of cervical cancer screening in a low-income setting.

Science.gov (United States)

Campos, Nicole G; Tsu, Vivien; Jeronimo, Jose; Njama-Meya, Denise; Mvundura, Mercy; Kim, Jane J

2017-09-01

With the availability of a low-cost HPV DNA test that can be administered by either a healthcare provider or a woman herself, programme planners require information on the costs and cost-effectiveness of implementing cervical cancer screening programmes in low-resource settings under different models of healthcare delivery. Using data from the START-UP demonstration project and a micro-costing approach, we estimated the health and economic impact of once-in-a-lifetime HPV self-collection campaign relative to clinic-based provider-collection of HPV specimens in Uganda. We used an individual-based Monte Carlo simulation model of the natural history of HPV and cervical cancer to estimate lifetime health and economic outcomes associated with screening with HPV DNA testing once in a lifetime (clinic-based provider-collection vs a self-collection campaign). Test performance and cost data were obtained from the START-UP demonstration project using a micro-costing approach. Model outcomes included lifetime risk of cervical cancer, total lifetime costs (in 2011 international dollars [I$]), and life expectancy. Cost-effectiveness ratios were expressed using incremental cost-effectiveness ratios (ICERs). When both strategies achieved 75% population coverage, ICERs were below Uganda's per capita GDP (self-collection: I$80 per year of life saved [YLS]; provider-collection: I$120 per YLS). When the self-collection campaign achieved coverage gains of 15-20%, it was more effective than provider-collection, and had a lower ICER unless coverage with both strategies was 50% or less. Findings were sensitive to cryotherapy compliance among screen-positive women and relative HPV test performance. The primary limitation of this analysis is that self-collection costs are based on a hypothetical campaign but are based on unit costs from Uganda. Once-in-a-lifetime screening with HPV self-collection may be very cost-effective and reduce cervical cancer risk by > 20% if coverage is high

Adequacy of relative and absolute risk models for lifetime risk estimate of radiation-induced cancer

International Nuclear Information System (INIS)

McBride, M.; Coldman, A.J.

1988-03-01

This report examines the applicability of the relative (multiplicative) and absolute (additive) models in predicting lifetime risk of radiation-induced cancer. A review of the epidemiologic literature, and a discussion of the mathematical models of carcinogenesis and their relationship to these models of lifetime risk, are included. Based on the available data, the relative risk model for the estimation of lifetime risk is preferred for non-sex-specific epithelial tumours. However, because of lack of knowledge concerning other determinants of radiation risk and of background incidence rates, considerable uncertainty in modelling lifetime risk still exists. Therefore, it is essential that follow-up of exposed cohorts be continued so that population-based estimates of lifetime risk are available

Impact of lifetime model selections on the reliability prediction of IGBT modules in modular multilevel converters

DEFF Research Database (Denmark)

Zhang, Yi; Wang, Huai; Wang, Zhongxu

2017-01-01

, this paper benchmarks the most commonly-employed lifetime models of power semiconductor devices for offshore Modular Multilevel Converters (MMC) based wind farms. The benchmarking reveals that the lifetime model selection has a significant impact on the lifetime estimation. The use of analytical lifetime...

Cost-utility of quadrivalent versus trivalent influenza vaccine in Brazil - comparison of outcomes from different static model types.

Science.gov (United States)

Van Bellinghen, Laure-Anne; Marijam, Alen; Tannus Branco de Araujo, Gabriela; Gomez, Jorge; Van Vlaenderen, Ilse

Influenza burden in Brazil is considerable with 4.2-6.4 million cases in 2008 and influenza-like-illness responsible for 16.9% of hospitalizations. Cost-effectiveness of influenza vaccination may be assessed by different types of models, with limitations due to data availability, assumptions, and modelling approach. To understand the impact of model complexity, the cost-utility of quadrivalent versus trivalent influenza vaccines in Brazil was estimated using three distinct models: a 1-year decision tree population model with three age groups (FLOU); a more detailed 1-year population model with five age groups (FLORA); and a more complex lifetime multi-cohort Markov model with nine age groups (FLORENCE). Analysis 1 (impact of model structure) compared each model using the same data inputs (i.e., best available data for FLOU). Analysis 2 (impact of increasing granularity) compared each model populated with the best available data for that model. Using the best data for each model, the discounted cost-utility ratio of quadrivalent versus trivalent influenza vaccine was R$20,428 with FLOU, R$22,768 with FLORA (versus R$20,428 in Analysis 1), and, R$19,257 with FLORENCE (versus R$22,490 in Analysis 1) using a lifetime horizon. Conceptual differences between FLORA and FLORENCE meant the same assumption regarding increased all-cause mortality in at-risk individuals had an opposite effect on the incremental cost-effectiveness ratio in Analysis 2 versus 1, and a proportionally higher number of vaccinated elderly in FLORENCE reduced this ratio in Analysis 2. FLOU provided adequate cost-effectiveness estimates with data in broad age groups. FLORA increased insights (e.g., in healthy versus at-risk, paediatric, respiratory/non-respiratory complications). FLORENCE provided greater insights and precision (e.g., in elderly, costs and complications, lifetime cost-effectiveness). All three models predicted a cost per quality-adjusted life year gained for quadrivalent versus

Modelling impacts of performance on the probability of reproducing, and thereby on productive lifespan, allow prediction of lifetime efficiency in dairy cows.

Science.gov (United States)

Phuong, H N; Blavy, P; Martin, O; Schmidely, P; Friggens, N C

2016-01-01

Reproductive success is a key component of lifetime efficiency - which is the ratio of energy in milk (MJ) to energy intake (MJ) over the lifespan, of cows. At the animal level, breeding and feeding management can substantially impact milk yield, body condition and energy balance of cows, which are known as major contributors to reproductive failure in dairy cattle. This study extended an existing lifetime performance model to incorporate the impacts that performance changes due to changing breeding and feeding strategies have on the probability of reproducing and thereby on the productive lifespan, and thus allow the prediction of a cow's lifetime efficiency. The model is dynamic and stochastic, with an individual cow being the unit modelled and one day being the unit of time. To evaluate the model, data from a French study including Holstein and Normande cows fed high-concentrate diets and data from a Scottish study including Holstein cows selected for high and average genetic merit for fat plus protein that were fed high- v. low-concentrate diets were used. Generally, the model consistently simulated productive and reproductive performance of various genotypes of cows across feeding systems. In the French data, the model adequately simulated the reproductive performance of Holsteins but significantly under-predicted that of Normande cows. In the Scottish data, conception to first service was comparably simulated, whereas interval traits were slightly under-predicted. Selection for greater milk production impaired the reproductive performance and lifespan but not lifetime efficiency. The definition of lifetime efficiency used in this model did not include associated costs or herd-level effects. Further works should include such economic indicators to allow more accurate simulation of lifetime profitability in different production scenarios.

Strongest model-independent bound on the lifetime of Dark Matter

CERN Document Server

Audren, Benjamin; Mangano, Gianpiero; Serpico, Pasquale Dario; Tram, Thomas

2014-01-01

Dark Matter is essential for structure formation in the late Universe so it must be stable on cosmological time scales. But how stable exactly? Only assuming decays into relativistic particles, we report an otherwise model independent bound on the lifetime of Dark Matter using current cosmological data. Since these decays affect only the low-$\\ell$ multipoles of the CMB, the Dark Matter lifetime is expected to correlate with the tensor-to-scalar ratio $r$ as well as curvature $\\Omega_k$. We consider two models, including $r$ and $r+\\Omega_k$ respectively, versus data from Planck, WMAP, WiggleZ and Baryon Acoustic Oscillations, with or without the BICEP2 data (if interpreted in terms of primordial gravitational waves). This results in a lower bound on the lifetime of CDM given by 160Gyr (without BICEP2) or 200Gyr (with BICEP2) at 95% confidence level.

Interpreting aerosol lifetimes using the GEOS-Chem model and constraints from radionuclide measurements

Energy Technology Data Exchange (ETDEWEB)

Croft, B. [Dalhousie Univ., Halifax (Canada). Dept. of Physics and Atmospheric Science; Pierce, J.R. [Dalhousie Univ., Halifax (Canada). Dept. of Physics and Atmospheric Science; Colorado State Univ., Fort Collins, CO (United States); Martin, R.V. [Dalhousie Univ., Halifax (Canada). Dept. of Physics and Atmospheric Science; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)

2014-07-01

Aerosol removal processes control global aerosol abundance, but the rate of that removal remains uncertain. A recent study of aerosol-bound radionuclide measurements after the Fukushima Daiichi nuclear power plant accident documents {sup 137}Cs removal (e-folding) times of 10.0-13.9 days, suggesting that mean aerosol lifetimes in the range of 3-7 days in global models might be too short by a factor of two. In this study, we attribute this discrepancy to differences between the e-folding and mean aerosol lifetimes. We implement a simulation of {sup 137}Cs and {sup 133}Xe into the GEOS-Chem chemical transport model and examine the removal rates for the Fukushima case. We find a general consistency between modelled and measured e-folding times. The simulated {sup 137}Cs global burden e-folding time is about 14 days. However, the simulated mean lifetime of aerosol-bound {sup 137}Cs over a 6-month post-accident period is only 1.8 days. We find that the mean lifetime depends strongly on the removal rates in the first few days after emissions, before the aerosols leave the boundary layer and are transported to altitudes and latitudes where lifetimes with respect to wet removal are longer by a few orders of magnitude. We present sensitivity simulations that demonstrate the influence of differences in altitude and location of the radionuclides on the mean lifetime. Global mean lifetimes are shown to strongly depend on the altitude of injection. The global mean {sup 137}Cs lifetime is more than one order of magnitude greater for the injection at 7 km than into the boundary layer above the Fukushima site. Instantaneous removal rates are slower during the first few days after the emissions for a free tropospheric versus boundary layer injection and this strongly controls the mean lifetimes. Global mean aerosol lifetimes for the GEOS-Chem model are 3-6 days, which is longer than that for the {sup 137}Cs injected at the Fukushima site (likely due to precipitation shortly after

The Susquehanna plant lifetime excellence program

International Nuclear Information System (INIS)

McNamara, R.W.

1988-01-01

This paper discusses how the Susquehanna plant lifetime excellence program (SPLEX) blends many of the objectives of a new managing for excellence program with plant life extension objectives to achieve excellence in the lifetime operation and availability of the two-unit Susquehanna steam electric station. Investments in lifetime excellence improvements will provide near-term, as well as plant life extension, benefits. A high-quality lifetime experience record, together with extensive, periodic technical assessments and cost-benefit analyses, will provide conclusive justification for future extensions of the unit operating licenses

Lifetime modelling with a Weibull law: comparison of three Bayesian Methods

International Nuclear Information System (INIS)

Billy, F.; Remy, E.; Bousquet, N.; Celeux, G.

2006-01-01

For a nuclear power plant, being able to estimate the lifetime of important components is strategic. But data is usually insufficient to do so. Thus, it is relevant to use expertise, together with data, in order to assess the value of lifetime on the grounds of both sources. The Bayesian frame and the choice of a Weibull law to model the random time for replacement are relevant. They have been chosen for this article. Two indicators are computed : the mean lifetime of any component and the mean residual lifetime of a given component, after it has been controlled. Three different Bayesian methods are compared on three sets of data. The article shows that the three methods lead to coherent results and that uncertainties are strongly reduced. The method developed around PMC has two main advantages: it models a conditional dependence of the two parameters of the Weibull law, which enables more coherent results on the prior; it has a parameter that weights the strength of the expertise. This last point is very important to do lifetime assessments, because then, expertise is not used to increase too small samples as much as to do a real extrapolation, far beyond what data itself say. (authors)

Modeling the Unites States government's economic cost of noise-induced hearing loss for a military population.

Science.gov (United States)

Tufts, Jennifer B; Weathersby, Paul K; Rodriguez, Francisco A

2010-05-01

The purpose of this paper is to demonstrate the feasibility and utility of developing economic cost models for noise-induced hearing loss (NIHL). First, we outline an economic model of NIHL for a population of US Navy sailors with an "industrial"-type noise exposure. Next, we describe the effect on NIHL-related cost of varying the two central model inputs--the noise-exposure level and the duration of exposure. Such an analysis can help prioritize promising areas, to which limited resources to reduce NIHL-related costs should be devoted. NIHL-related costs borne by the US government were computed on a yearly basis using a finite element approach that took into account varying levels of susceptibility to NIHL. Predicted hearing thresholds for the population were computed with ANSI S3.44-1996 and then used as the basis for the calculation of NIHL-related costs. Annual and cumulative costs were tracked. Noise-exposure level and duration were systematically varied to determine their effects on the expected lifetime NIHL-related cost of a specific US Navy sailor population. Our nominal noise-exposure case [93 dB(A) for six years] yielded a total expected lifetime cost of US $13,472 per sailor, with plausible lower and upper bounds of US $2,500 and US $26,000. Starting with the nominal case, a decrease of 50% in exposure level or duration would yield cost savings of approximately 23% and 19%, respectively. We concluded that a reduction in noise level would be more somewhat more cost-effective than the same percentage reduction in years of exposure. Our economic cost model can be used to estimate the changes in NIHL-related costs that would result from changes in noise-exposure level and/or duration for a single military population. Although the model is limited at present, suggestions are provided for adapting it to civilian populations.

Cost-effectiveness of a school-based health promotion program in Canada: A life-course modeling approach.

Directory of Open Access Journals (Sweden)

John Paul Ekwaru

Full Text Available The Alberta Project Promoting active Living and healthy Eating in Schools (APPLE Schools has been recognized as a "best practice" in preventing childhood obesity. To inform decision making on the economic implications of APPLE Schools and to justify investment, we evaluated the project's cost-effectiveness following a life-course approach.We developed a state transition model for the lifetime progression of body weight status comparing elementary school students attending APPLE Schools and control schools. This model quantified the lifetime impact of APPLE Schools in terms of prevention of excess body weight, chronic disease and improved quality-adjusted life years (QALY, from a school system's cost perspective. Both costs and health outcomes were discounted to their present value using 3% discount rate.The incremental cost-effectiveness ratio(ICER of APPLE schools was CA$33,421 per QALY gained, and CA$1,555, CA$1,709 and CA$14,218 per prevented person years of excess weight, obesity and chronic disease, respectively. These estimates show that APPLE Schools is cost effective at a threshold of ICER < CA$50,000. In probabilistic sensitivity analysis, APPLE Schools was cost effective more than 64% of the time per QALY gained, when using a threshold of ICERcost-effective intervention for obesity prevention and reduction of chronic disease risk over the lifetime. Expanding the coverage and allocating resources towards school-based programs like the APPLE Schools program, is likely to reduce the public health burden of obesity and chronic diseases.

Lifetime earnings for physicians across specialties.

Science.gov (United States)

Leigh, J Paul; Tancredi, Daniel; Jerant, Anthony; Romano, Patrick S; Kravitz, Richard L

2012-12-01

Earlier studies estimated annual income differences across specialties, but lifetime income may be more relevant given physicians' long-term commitments to specialties. Annual income and work hours data were collected from 6381 physicians in the nationally representative 2004-2005 Community Tracking Study. Data regarding years of residency were collected from AMA FREIDA. Present value models were constructed assuming 3% discount rates. Estimates were adjusted for demographic and market covariates. Sensitivity analyses included 4 alternative models involving work hours, retirement, exogenous variables, and 1% discount rate. Estimates were generated for 4 broad specialty categories (Primary Care, Surgery, Internal Medicine and Pediatric Subspecialties, and Other), and for 41 specific specialties. The estimates of lifetime earnings for the broad categories of Surgery, Internal Medicine and Pediatric Subspecialties, and Other specialties were $1,587,722, $1,099,655, and $761,402 more than for Primary Care. For the 41 specific specialties, the top 3 (with family medicine as reference) were neurological surgery ($2,880,601), medical oncology ($2,772,665), and radiation oncology ($2,659,657). The estimates from models with varying rates of retirement and including only exogenous variables were similar to those in the preferred model. The 1% discount model generated estimates that were roughly 150% larger than the 3% model. There was considerable variation in the lifetime earnings across physician specialties. After accounting for varying residency years and discounting future earnings, primary care specialties earned roughly $1-3 million less than other specialties. Earnings' differences across specialties may undermine health reform efforts to control costs and ensure adequate numbers of primary care physicians.

A new lifetime estimation model for a quicker LED reliability prediction

Science.gov (United States)

Hamon, B. H.; Mendizabal, L.; Feuillet, G.; Gasse, A.; Bataillou, B.

2014-09-01

LED reliability and lifetime prediction is a key point for Solid State Lighting adoption. For this purpose, one hundred and fifty LEDs have been aged for a reliability analysis. LEDs have been grouped following nine current-temperature stress conditions. Stress driving current was fixed between 350mA and 1A and ambient temperature between 85C and 120°C. Using integrating sphere and I(V) measurements, a cross study of the evolution of electrical and optical characteristics has been done. Results show two main failure mechanisms regarding lumen maintenance. The first one is the typically observed lumen depreciation and the second one is a much more quicker depreciation related to an increase of the leakage and non radiative currents. Models of the typical lumen depreciation and leakage resistance depreciation have been made using electrical and optical measurements during the aging tests. The combination of those models allows a new method toward a quicker LED lifetime prediction. These two models have been used for lifetime predictions for LEDs.

Counting the costs of overweight and obesity: modeling clinical and cost outcomes.

Science.gov (United States)

Tucker, Daniel M D; Palmer, Andrew J; Valentine, William J; Roze, Stéphane; Ray, Joshua A

2006-03-01

To quantify changes in clinical and cost outcomes associated with increasing levels of body mass index (BMI) in a US setting. A semi-Markov model was developed to project and compare life expectancy (LE), quality-adjusted life expectancy (QALE) and direct medical costs associated with distinct levels of BMI in simulated adult cohorts over a lifetime horizon. Cohort definitions included age (20-65 years), gender, race, and BMI (24-45 kg m(-2)). Cohorts were exclusively male or female and either Caucasian or African-American. Mortality rates were adjusted according to these factors using published data. BMI progression over time was modeled. BMI-dependent US direct medical costs were derived from published sources and inflated to year 2004 values. A third party reimbursement perspective was taken. QALE and costs were discounted at 3% per annum. In young Caucasian cohorts LE decreased as BMI increased. However, in older Caucasian cohorts the BMI associated with greatest longevity was higher than 25 kg m(-2). A similar pattern was observed in young adult African-American cohorts. A survival paradox was projected in older African-American cohorts, with some BMI levels in the obese category associated with greatest longevity. QALE in all four race/gender cohorts followed similar patterns to LE. Sensitivity analyses demonstrated that simulating BMI progression over time had an important impact on results. Direct costs in all four cohorts increased with BMI, with a few exceptions. Optimal BMI, in terms of longevity, varied between race/gender cohorts and within these cohorts, according to age, contributing to the debate over what BMI level or distribution should be considered ideal in terms of mortality risk. Simulating BMI progression over time had a substantial impact on health outcomes and should be modeled in future health economic analyses of overweight and obesity.

Modeling the fiscal costs and benefits of alternative treatment strategies in the United Kingdom for chronic hepatitis C.

Science.gov (United States)

Connolly, Mark P; Kotsopoulos, Nikos; Ustianowski, Andrew

2018-01-01

Hepatitis C (HCV) infection causes substantial direct health costs, but also impacts broader societal and governmental costs, such as tax revenue and social protection benefits. This study investigated the broader fiscal costs and benefits of curative interventions for chronic Hepatitis C (CHC) that allow individuals to avoid long-term HCV attributed health conditions. A prospective cohort model, assessing the long-term fiscal consequences of policy decisions, was developed for HCV infected individuals, following the generational accounting analytic framework that combines age-specific lifetime gross taxes paid and governmental transfers received (i.e. healthcare and social support costs). The analysis assessed the burden of a theoretical cohort of untreated HCV infected patients with the alternative of treating these patients with a highly efficacious curative intervention (ledipasvir/sofosbuvir [LDV/SOF]). It also compared treating patients at all fibrosis stages (Stages F0-F4) compared to late treatment (Stage F4). Based on projected lifetime work activity and taxes paid, the treated cohort paid an additional £5,900 per patient compared to the untreated cohort. Lifetime government disability costs of £97,555 and £125,359 per patient for treated cohort vs no treatment cohort were estimated, respectively. Lifetime direct healthcare costs in the treated cohort were £32,235, compared to non-treated cohort of £26,424, with an incremental healthcare costs increase of £5,901 per patient. The benefit cost ratio (BCR) of total government benefits and savings relative to government treatment costs (including LDV/SOF) ranged from 1.8-5.6. Treating patients early resulted in 77% less disability costs, 43% lower healthcare costs, and 33% higher tax revenue. The ability to cure Hepatitis C offers considerable fiscal benefits beyond direct medical costs and savings attributed to reduced disability costs, public allowances, and improved tax revenue. Changes in parameters

Accelerated lifetime testing methodology for lifetime estimation of Lithium-ion batteries used in augmented wind power plants

DEFF Research Database (Denmark)

Stroe, Daniel Ioan; Swierczynski, Maciej Jozef; Stan, Ana-Irina

2013-01-01

The development of lifetime estimation models for Lithium-ion battery cells, which are working under highly variable mission profiles characteristic for wind power plant applications, requires a lot of expenditures and time resources. Therefore, batteries have to be tested under accelerated...... lifetime ageing conditions. This paper presents a three-stage methodology used for accelerated lifetime testing of Lithium-ion batteries. The results obtained at the end of the accelerated ageing process can be used for the parametrization of a performance-degradation lifetime model. In the proposed...... methodology both calendar and cycling lifetime tests are considered since both components are influencing the lifetime of Lithium-ion batteries. The methodology proposes also a lifetime model verification stage, where Lithium-ion battery cells are tested at normal operating conditions using an application...

Electro-thermal Modeling for Junction Temperature Cycling-Based Lifetime Prediction of a Press-Pack IGBT 3L-NPC-VSC Applied to Large Wind Turbines

DEFF Research Database (Denmark)

Senturk, Osman Selcuk; Munk-Nielsen, Stig; Teodorescu, Remus

2011-01-01

Reliability is a critical criterion for multi-MW wind turbines, which are being employed with increasing numbers in wind power plants, since they operate under harsh conditions and have high maintenance cost due to their remote locations. In this study, the wind turbine grid-side converter...... reliability is investigated regarding IGBT lifetime based on junction temperature cycling for the grid-side press-pack IGBT 3L-NPC-VSC, which is a state-of-the art high reliability solution. In order to acquire IGBT junction temperatures for given wind power profiles and to use them in IGBT lifetime...... prediction, the converter electro-thermal model including electrical, power loss, and dynamical thermal models is developed with the main focus on the thermal modeling regarding converter topology, switch technology, and physical structure. Moreover, these models are simplified for their practical...

Charmed particle lifetimes

International Nuclear Information System (INIS)

Rosner, J.L.

1979-01-01

Conventional estimates are reviewed for charmed particle lifetimes. Free-quark models give values of (a few) x 10 -13 sec to (a few) x 10 -12 sec. The shorter of these values also follows from an extrapolation based on D → Ke/sup nu/. Possible differences among the lifetimes and production rates of D 0 , D + , F + , C 0 + , the heavy lepton tau, and the fifth quark b are discussed. Extreme values of mixing angles in a six-quark model could extend charmed particle lifetimes by a factor of at most three from the above estimates, while shorter lifetimes than those predicted could occur for some species like D 0 or F + if their nonleptonic decays were enhanced. The predictions are discussed in the light of some current experimental results, and it is estimated that sigma(pp → charm) approx. = 10 μb at 400 GeV/c. 95 references

Positron lifetimes in deformed copper

International Nuclear Information System (INIS)

Hinode, Kenji; Tanigawa, Shoichiro; Doyama, Masao

1976-01-01

Positron lifetime measurements were performed for Cu samples with different densities of lattice defects. The lifetime spectra were successfully resolved into two components with the help of the well established analysis program. Obtained results were quite consistent with those expected from the trapping model. The positron trapping mechanism from free to trapped states and the initial condition of the model were especially checked. Deduced values obtained for tau sub(c) (lifetime of free positrons) and tau sub(t) (lifetime of trapped positrons) were 122+-5 psec and 176+-5 psec, respectively. (auth.)

Fluorescence lifetime imaging using light emitting diodes

Energy Technology Data Exchange (ETDEWEB)

Kennedy, Gordon T; Munro, Ian; Poher, Vincent; French, Paul M W; Neil, Mark A A [Blackett Laboratory, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Elson, Daniel S [Institute of Biomedical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Hares, Jonathan D [Kentech Instruments Ltd, Unit 9, Hall Farm Workshops, South Moreton, Didcot, Oxfordshire, OX11 9AG (United Kingdom)], E-mail: gordon.kennedy@imperial.ac.uk

2008-05-07

We demonstrate flexible use of low cost, high-power light emitting diodes as illumination sources for fluorescence lifetime imaging (FLIM). Both time-domain and frequency-domain techniques have been implemented at wavelengths spanning the range 450-640 nm. Additionally, we demonstrate optically sectioned fluorescence lifetime imaging by combining structured illumination with frequency-domain FLIM.

Long-term fiscal implications of subsidizing in-vitro fertilization in Sweden: a lifetime tax perspective.

Science.gov (United States)

Svensson, Anders; Connolly, Mark; Gallo, Federico; Hägglund, Leif

2008-11-01

In Sweden approximately 3% of annual births are conceived using assisted reproductive technologies (ART). In light of increasing use of ART in Sweden we estimate the lifetime future tax revenues of a child conceived by in-vitro fertilization (IVF) to establish whether public subsidy of IVF represents sound fiscal policy. A modified generational accounting model was developed to calculate the net present value (NPV) of average investment costs required to achieve an IVF-conceived child. The model simulates direct lifetime financial interactions between the child and the Swedish government. Within the model we assume average direct financial transfers are made to the individual (eg, child allowance, education, health care, pension, etc). In return, the individual transfers resources to the government through taxation based on anticipated average earnings. The difference between direct transfers and gross taxes paid equals the net-tax contribution. Individual tax contributions were held constant in the model. Based on average life-expectancy an individual born in 2005 will pay an undiscounted 32.5 million SEK in taxes to the Swedish government and receive 20.9 million SEK in direct financial transfers over their lifetime. When these figures are discounted and IVF costs are included in the analysis we obtain a lifetime NPV of 254,000 SEK with a break-even point at age 41 (the age of achieving a positive NPV) for an individual conceived through IVF. Based on results presented here we conclude that State-funded IVF in Sweden does not negatively impact the long run fiscal budget. Conversely, over an average lifetime an IVF offspring returns a positive net value to the State.

Modeling and Application of Customer Lifetime Value in Online Retail

OpenAIRE

Pavel Jasek; Lenka Vrana; Lucie Sperkova; Zdenek Smutny; Marek Kobulsky

2018-01-01

This article provides an empirical statistical analysis and discussion of the predictive abilities of selected customer lifetime value (CLV) models that could be used in online shopping within e-commerce business settings. The comparison of CLV predictive abilities, using selected evaluation metrics, is made on selected CLV models: Extended Pareto/NBD model (EP/NBD), Markov chain model and Status Quo model. The article uses six online store datasets with annual revenues in the order of tens o...

Population Dynamics and Cost-Benefit Analysis. An Attempt to Relate Population Dynamics via Lifetime Reproductive Success to Short-Term Decisions

NARCIS (Netherlands)

Tinbergen, J.M.; Balen, J.H. van; Drent, P.J.; Cavé, A.J.; Mertens, J.A.L.; Boer-Hazewinkel, J. den

1987-01-01

1. The aim of this article is to explore whether cost-benefit analysis of behaviour may help to understand the population dynamics of a species. The Great Tit is taken as an example. 2. The lifetime reproductive success in different populations of Great Tits amounts from 0.7 (Hoge Veluwe, Wytham) to

Temperature dependence of o-Ps annihilation lifetime in non-uniform cylindrical pores in comparison with ETE model

Energy Technology Data Exchange (ETDEWEB)

Khaghani, Morteza, E-mail: m.khaghani@pgs.usb.ac.ir; Mehmandoost-Khajeh-Dad, Ali Akbar, E-mail: mehmandoost@phys.usb.ac.ir

2017-04-01

Highlights: • Using the well known multi-physics program COMSOL calculating o-Ps annihilation lifetime in complex geometries. • Investigation of shape non-uniformity of cylindrical pores on o-Ps annihilation lifetime. • Verifying temperature dependency of o-Ps lifetime in non-uniform cylindrical pores. • Suggesting PALS at low temperature as a method to verify pore uniformity in porous material. - Abstract: Ortho-positronium (o-Ps) annihilation lifetime was calculated in non-uniform cylinder-shaped pores by solving Schrodinger equation using a well-known multi-physics program called COMSOL. The o-Ps annihilation lifetime variation in terms of temperature was calculated on the basis of ETE model via a numerical method. The COMSOL simulations indicate that as long as the pore is uniform cylinder-shaped, the results agree with those of two-dimensional ETE model, whereas deformations in the cylinder shape (indentation or protrusion) change the temperature behavior of ETE model and, thereby, higher values are predicted for o-Ps lifetime in the pore at lower temperatures. The geometry of the non-uniform cylinder-shaped pores, which is accompanied by empirical evidence, can be used for the analysis of empirical results obtained from positron lifetime spectroscopy in different temperatures.

Population Screening for Hereditary Haemochromatosis in Australia: Construction and Validation of a State-Transition Cost-Effectiveness Model.

Science.gov (United States)

de Graaff, Barbara; Si, Lei; Neil, Amanda L; Yee, Kwang Chien; Sanderson, Kristy; Gurrin, Lyle C; Palmer, Andrew J

2017-03-01

HFE-associated haemochromatosis, the most common monogenic disorder amongst populations of northern European ancestry, is characterised by iron overload. Excess iron is stored in parenchymal tissues, leading to morbidity and mortality. Population screening programmes are likely to improve early diagnosis, thereby decreasing associated disease. Our aim was to develop and validate a health economics model of screening using utilities and costs from a haemochromatosis cohort. A state-transition model was developed with Markov states based on disease severity. Australian males (aged 30 years) and females (aged 45 years) of northern European ancestry were the target populations. The screening strategy was the status quo approach in Australia; the model was run over a lifetime horizon. Costs were estimated from the government perspective and reported in 2015 Australian dollars ($A); costs and quality-adjusted life-years (QALYs) were discounted at 5% annually. Model validity was assessed using goodness-of-fit analyses. Second-order Monte-Carlo simulation was used to account for uncertainty in multiple parameters. For validity, the model reproduced mortality, life expectancy (LE) and prevalence rates in line with published data. LE for C282Y homozygote males and females were 49.9 and 40.2 years, respectively, slightly lower than population rates. Mean (95% confidence interval) QALYS were 15.7 (7.7-23.7) for males and 14.4 (6.7-22.1) for females. Mean discounted lifetime costs for C282Y homozygotes were $A22,737 (3670-85,793) for males and $A13,840 (1335-67,377) for females. Sensitivity analyses revealed discount rates and prevalence had the greatest impacts on outcomes. We have developed a transparent, validated health economics model of C282Y homozygote haemochromatosis. The model will be useful to decision makers to identify cost-effective screening strategies.

Lifetime risks for aneurysmal subarachnoid haemorrhage: multivariable risk stratification.

Science.gov (United States)

Vlak, Monique H M; Rinkel, Gabriel J E; Greebe, Paut; Greving, Jacoba P; Algra, Ale

2013-06-01

The overall incidence of aneurysmal subarachnoid haemorrhage (aSAH) in western populations is around 9 per 100 000 person-years, which confers to a lifetime risk of around half per cent. Risk factors for aSAH are usually expressed as relative risks and suggest that absolute risks vary considerably according to risk factor profiles, but such estimates are lacking. We aimed to estimate incidence and lifetime risks of aSAH according to risk factor profiles. We used data from 250 patients admitted with aSAH and 574 sex-matched and age-matched controls, who were randomly retrieved from general practitioners files. We determined independent prognostic factors with multivariable logistic regression analyses and assessed discriminatory performance using the area under the receiver operating characteristic curve. Based on the prognostic model we predicted incidences and lifetime risks of aSAH for different risk factor profiles. The four strongest independent predictors for aSAH, namely current smoking (OR 6.0; 95% CI 4.1 to 8.6), a positive family history for aSAH (4.0; 95% CI 2.3 to 7.0), hypertension (2.4; 95% CI 1.5 to 3.8) and hypercholesterolaemia (0.2; 95% CI 0.1 to 0.4), were used in the final prediction model. This model had an area under the receiver operating characteristic curve of 0.73 (95% CI 0.69 to 0.76). Depending on sex, age and the four predictors, the incidence of aSAH ranged from 0.4/100 000 to 298/100 000 person-years and lifetime risk between 0.02% and 7.2%. The incidence and lifetime risk of aSAH in the general population varies widely according to risk factor profiles. Whether persons with high risks benefit from screening should be assessed in cost-effectiveness studies.

Systematic review of model-based analyses reporting the cost-effectiveness and cost-utility of cardiovascular disease management programs.

Science.gov (United States)

Maru, Shoko; Byrnes, Joshua; Whitty, Jennifer A; Carrington, Melinda J; Stewart, Simon; Scuffham, Paul A

2015-02-01

The reported cost effectiveness of cardiovascular disease management programs (CVD-MPs) is highly variable, potentially leading to different funding decisions. This systematic review evaluates published modeled analyses to compare study methods and quality. Articles were included if an incremental cost-effectiveness ratio (ICER) or cost-utility ratio (ICUR) was reported, it is a multi-component intervention designed to manage or prevent a cardiovascular disease condition, and it addressed all domains specified in the American Heart Association Taxonomy for Disease Management. Nine articles (reporting 10 clinical outcomes) were included. Eight cost-utility and two cost-effectiveness analyses targeted hypertension (n=4), coronary heart disease (n=2), coronary heart disease plus stoke (n=1), heart failure (n=2) and hyperlipidemia (n=1). Study perspectives included the healthcare system (n=5), societal and fund holders (n=1), a third party payer (n=3), or was not explicitly stated (n=1). All analyses were modeled based on interventions of one to two years' duration. Time horizon ranged from two years (n=1), 10 years (n=1) and lifetime (n=8). Model structures included Markov model (n=8), 'decision analytic models' (n=1), or was not explicitly stated (n=1). Considerable variation was observed in clinical and economic assumptions and reporting practices. Of all ICERs/ICURs reported, including those of subgroups (n=16), four were above a US$50,000 acceptability threshold, six were below and six were dominant. The majority of CVD-MPs was reported to have favorable economic outcomes, but 25% were at unacceptably high cost for the outcomes. Use of standardized reporting tools should increase transparency and inform what drives the cost-effectiveness of CVD-MPs. © The European Society of Cardiology 2014.

Congenital toxoplasmosis in Austria: Prenatal screening for prevention is cost-saving

Science.gov (United States)

Prusa, Andrea-Romana; Kasper, David C.; Sawers, Larry; Walter, Evelyn; Hayde, Michael

2017-01-01

Background Primary infection of Toxoplasma gondii during pregnancy can be transmitted to the unborn child and may have serious consequences, including retinochoroiditis, hydrocephaly, cerebral calcifications, encephalitis, splenomegaly, hearing loss, blindness, and death. Austria, a country with moderate seroprevalence, instituted mandatory prenatal screening for toxoplasma infection to minimize the effects of congenital transmission. This work compares the societal costs of congenital toxoplasmosis under the Austrian national prenatal screening program with the societal costs that would have occurred in a No-Screening scenario. Methodology/Principal findings We retrospectively investigated data from the Austrian Toxoplasmosis Register for birth cohorts from 1992 to 2008, including pediatric long-term follow-up until May 2013. We constructed a decision-analytic model to compare lifetime societal costs of prenatal screening with lifetime societal costs estimated in a No-Screening scenario. We included costs of treatment, lifetime care, accommodation of injuries, loss of life, and lost earnings that would have occurred in a No-Screening scenario and compared them with the actual costs of screening, treatment, lifetime care, accommodation, loss of life, and lost earnings. We replicated that analysis excluding loss of life and lost earnings to estimate the budgetary impact alone. Our model calculated total lifetime costs of €103 per birth under prenatal screening as carried out in Austria, saving €323 per birth compared with No-Screening. Without screening and treatment, lifetime societal costs for all affected children would have been €35 million per year; the implementation costs of the Austrian program are less than €2 million per year. Calculating only the budgetary impact, the national program was still cost-saving by more than €15 million per year and saved €258 million in 17 years. Conclusions/Significance Cost savings under a national program of

Congenital toxoplasmosis in Austria: Prenatal screening for prevention is cost-saving.

Directory of Open Access Journals (Sweden)

Andrea-Romana Prusa

2017-07-01

Full Text Available Primary infection of Toxoplasma gondii during pregnancy can be transmitted to the unborn child and may have serious consequences, including retinochoroiditis, hydrocephaly, cerebral calcifications, encephalitis, splenomegaly, hearing loss, blindness, and death. Austria, a country with moderate seroprevalence, instituted mandatory prenatal screening for toxoplasma infection to minimize the effects of congenital transmission. This work compares the societal costs of congenital toxoplasmosis under the Austrian national prenatal screening program with the societal costs that would have occurred in a No-Screening scenario.We retrospectively investigated data from the Austrian Toxoplasmosis Register for birth cohorts from 1992 to 2008, including pediatric long-term follow-up until May 2013. We constructed a decision-analytic model to compare lifetime societal costs of prenatal screening with lifetime societal costs estimated in a No-Screening scenario. We included costs of treatment, lifetime care, accommodation of injuries, loss of life, and lost earnings that would have occurred in a No-Screening scenario and compared them with the actual costs of screening, treatment, lifetime care, accommodation, loss of life, and lost earnings. We replicated that analysis excluding loss of life and lost earnings to estimate the budgetary impact alone. Our model calculated total lifetime costs of €103 per birth under prenatal screening as carried out in Austria, saving €323 per birth compared with No-Screening. Without screening and treatment, lifetime societal costs for all affected children would have been €35 million per year; the implementation costs of the Austrian program are less than €2 million per year. Calculating only the budgetary impact, the national program was still cost-saving by more than €15 million per year and saved €258 million in 17 years.Cost savings under a national program of prenatal screening for toxoplasma infection and

Congenital toxoplasmosis in Austria: Prenatal screening for prevention is cost-saving.

Science.gov (United States)

Prusa, Andrea-Romana; Kasper, David C; Sawers, Larry; Walter, Evelyn; Hayde, Michael; Stillwaggon, Eileen

2017-07-01

Primary infection of Toxoplasma gondii during pregnancy can be transmitted to the unborn child and may have serious consequences, including retinochoroiditis, hydrocephaly, cerebral calcifications, encephalitis, splenomegaly, hearing loss, blindness, and death. Austria, a country with moderate seroprevalence, instituted mandatory prenatal screening for toxoplasma infection to minimize the effects of congenital transmission. This work compares the societal costs of congenital toxoplasmosis under the Austrian national prenatal screening program with the societal costs that would have occurred in a No-Screening scenario. We retrospectively investigated data from the Austrian Toxoplasmosis Register for birth cohorts from 1992 to 2008, including pediatric long-term follow-up until May 2013. We constructed a decision-analytic model to compare lifetime societal costs of prenatal screening with lifetime societal costs estimated in a No-Screening scenario. We included costs of treatment, lifetime care, accommodation of injuries, loss of life, and lost earnings that would have occurred in a No-Screening scenario and compared them with the actual costs of screening, treatment, lifetime care, accommodation, loss of life, and lost earnings. We replicated that analysis excluding loss of life and lost earnings to estimate the budgetary impact alone. Our model calculated total lifetime costs of €103 per birth under prenatal screening as carried out in Austria, saving €323 per birth compared with No-Screening. Without screening and treatment, lifetime societal costs for all affected children would have been €35 million per year; the implementation costs of the Austrian program are less than €2 million per year. Calculating only the budgetary impact, the national program was still cost-saving by more than €15 million per year and saved €258 million in 17 years. Cost savings under a national program of prenatal screening for toxoplasma infection and treatment are

Development of a lifetime prediction model for lithium-ion batteries based on extended accelerated aging test data

Science.gov (United States)

Ecker, Madeleine; Gerschler, Jochen B.; Vogel, Jan; Käbitz, Stefan; Hust, Friedrich; Dechent, Philipp; Sauer, Dirk Uwe

2012-10-01

Battery lifetime prognosis is a key requirement for successful market introduction of electric and hybrid vehicles. This work aims at the development of a lifetime prediction approach based on an aging model for lithium-ion batteries. A multivariable analysis of a detailed series of accelerated lifetime experiments representing typical operating conditions in hybrid electric vehicle is presented. The impact of temperature and state of charge on impedance rise and capacity loss is quantified. The investigations are based on a high-power NMC/graphite lithium-ion battery with good cycle lifetime. The resulting mathematical functions are physically motivated by the occurring aging effects and are used for the parameterization of a semi-empirical aging model. An impedance-based electric-thermal model is coupled to the aging model to simulate the dynamic interaction between aging of the battery and the thermal as well as electric behavior. Based on these models different drive cycles and management strategies can be analyzed with regard to their impact on lifetime. It is an important tool for vehicle designers and for the implementation of business models. A key contribution of the paper is the parameterization of the aging model by experimental data, while aging simulation in the literature usually lacks a robust empirical foundation.

Optimal household refrigerator replacement policy for life cycle energy, greenhouse gas emissions, and cost

International Nuclear Information System (INIS)

Kim, Hyung Chul; Keoleian, Gregory A.; Horie, Yuhta A.

2006-01-01

Although the last decade witnessed dramatic progress in refrigerator efficiencies, inefficient, outdated refrigerators are still in operation, sometimes consuming more than twice as much electricity per year compared with modern, efficient models. Replacing old refrigerators before their designed lifetime could be a useful policy to conserve electric energy and greenhouse gas emissions. However, from a life cycle perspective, product replacement decisions also induce additional economic and environmental burdens associated with disposal of old models and production of new models. This paper discusses optimal lifetimes of mid-sized refrigerator models in the US, using a life cycle optimization model based on dynamic programming. Model runs were conducted to find optimal lifetimes that minimize energy, global warming potential (GWP), and cost objectives over a time horizon between 1985 and 2020. The baseline results show that depending on model years, optimal lifetimes range 2-7 years for the energy objective, and 2-11 years for the GWP objective. On the other hand, an 18-year of lifetime minimizes the economic cost incurred during the time horizon. Model runs with a time horizon between 2004 and 2020 show that current owners should replace refrigerators that consume more than 1000 kWh/year of electricity (typical mid-sized 1994 models and older) as an efficient strategy from both cost and energy perspectives

Determining of the Optimal Device Lifetime using Mathematical Renewal Models

Directory of Open Access Journals (Sweden)

Knežo Dušan

2016-05-01

Full Text Available Paper deals with the operations and equipment of the machine in the process of organizing production. During operation machines require maintenance and repairs, while in case of failure or machine wears it is necessary to replace them with new ones. For the process of replacement of old machines with new ones the term renewal is used. Qualitative aspects of the renewal process observe renewal theory, which is mainly based on the theory of probability and mathematical statistics. Devices lifetimes are closely related to the renewal of the devices. Presented article is focused on mathematical deduction of mathematical renewal models and determining optimal lifetime of the devices from the aspect of expenditures on renewal process.

Future transportation: Lifetime considerations and framework for sustainability assessment

International Nuclear Information System (INIS)

Sweeting, Walter J.; Winfield, Patricia H.

2012-01-01

Modern society cannot exist without mobility. It is now essential to maintain access to everyday necessities, as well as being a vital part of most economies. However, our current transportation system is placing unsustainable demands on finite resources of fossil fuels, minerals and materials; change is therefore essential. Identifying rational choices is difficult because a future transport option must not only abate these demands over the entire lifetime, but do so at an affordable cost whilst maintaining acceptable levels of utility. This paper offers a framework to evaluate powertrains for whole life criteria, in order to help validate current and future developments. It supports integrated comparisons of both fuel and vehicle technology combinations for cost, energy and greenhouse gas emissions throughout a vehicles lifetime. Case studies illustrate the use of this framework. All powertrains were found to require considerable amounts of energy and emit some emissions over their whole lifetime. Significant benefits over incumbent vehicles were found to be potentially attainable through the use of alternative powertrains. However, the majority of these benefits were currently found to increase user costs, worsen the vehicle production impacts and be heavily reliant on the source of the vehicles in-use energy. - Highlight: ► Cost, energy and GHG emissions throughout a vehicle’s lifetime are evaluated. ► This paper offers a structure to evaluate powertrains for whole life criteria. ► Substantial amounts of energy and emissions were evident for all options. ► Significant environmental benefits over incumbent vehicles were found. ► In-use benefits were shown to shift impacts to other phases of a vehicle’s lifetime.

Cyclic plasticity and lifetime of the nickel-based Alloy C-263: Experiments, models and component simulation

Directory of Open Access Journals (Sweden)

Maier G.

2014-01-01

Full Text Available The present work deals with the thermomechanical fatigue and low-cycle fatigue behavior of C-263 in two different material conditions. Microstructural characteristics and fracture modes are investigated with light and electron microscopy. The experimental results indicate that viscoplastic deformations depend on the heat treatment or rather on the current state of the microstructure. The measured data are used to adjust the parameters of a Chaboche type model and a fracture-mechanics based model for fatigue lifetime prediction. The Chaboche model is able to describe the essential phenomena of time and temperature dependent cyclic plasticity including the complex cyclic hardening during thermo-cyclic loading of both material conditions with a unique set of material parameters. This could be achieved by including an additional internal variable into the Chaboche model which accounts for changes in the precipitation microstructure during high temperature loading. Furthermore, the proposed lifetime model is well suited for a common fatigue life prediction of both investigated heats. The deformation and lifetime models are implemented into a user defined material routine. In this work, the material routine is applied for the lifetime prediction of a critical power plant component using the finite element method.

Lifetime costs of lung transplantation : Estimation of incremental costs

NARCIS (Netherlands)

VanEnckevort, PJ; Koopmanschap, MA; Tenvergert, EM; VanderBij, W; Rutten, FFH

1997-01-01

Despite an expanding number of centres which provide lung transplantation, information about the incremental costs of lung transplantation is scarce. From 1991 until 1995, in The Netherlands a technology assessment was performed which provided information about the incremental costs of lung

Accelerated Lifetime Testing Methodology for Lifetime Estimation of Lithium-ion Batteries used in Augmented Wind Power Plants

DEFF Research Database (Denmark)

Stroe, Daniel Ioan; Swierczynski, Maciej Jozef; Stan, Ana-Irina

2014-01-01

The development of lifetime estimation models for Lithium-ion battery cells, which are working under highly variable mission profiles characteristic for wind power plant applications, requires a lot of expenditures and time resources. Therefore, batteries have to be tested under accelerated...... lifetime ageing conditions. This paper presents a three-stage methodology used for accelerated lifetime testing of Lithium ion batteries. The results obtained at the end of the accelerated ageing process were used for the parametrization of a performance-degradation lifetime model, which is able to predict...... both the capacity fade and the power capability decrease of the selected Lithium-ion battery cells. In the proposed methodology both calendar and cycling lifetime tests were considered since both components are influencing the lifetime of Lithium-ion batteries. Furthermore, the proposed methodology...

Deriving estimates of individual variability in genetic potentials of performance traits for 3 dairy breeds, using a model of lifetime nutrient partitioning

DEFF Research Database (Denmark)

Phuong, H N; Martin, O; de Boer, I J M

2015-01-01

, body reserve usage, and growth for different genotypes of cow. Moreover, it can be used to separate genetic variability in performance between individual cows from environmental noise. The model enables simulation of the effects of a genetic selection strategy on lifetime efficiency of individual cows......, which has a main advantage of including the rearing costs, and thus, can be used to explore the impact of future selection on animal performance and efficiency....

Studies on Mathematical Models of Wet Adhesion and Lifetime Prediction of Organic Coating/Steel by Grey System Theory.

Science.gov (United States)

Meng, Fandi; Liu, Ying; Liu, Li; Li, Ying; Wang, Fuhui

2017-06-28

A rapid degradation of wet adhesion is the key factor controlling coating lifetime, for the organic coatings under marine hydrostatic pressure. The mathematical models of wet adhesion have been studied by Grey System Theory (GST). Grey models (GM) (1, 1) of epoxy varnish (EV) coating/steel and epoxy glass flake (EGF) coating/steel have been established, and a lifetime prediction formula has been proposed on the basis of these models. The precision assessments indicate that the established models are accurate, and the prediction formula is capable of making precise lifetime forecasting of the coatings.

Lifetime value in business process

Directory of Open Access Journals (Sweden)

Martin Souček

2011-01-01

Full Text Available The paper focuses on lifetime value assessment and its implementation and application in business processes. The lifetime value is closely connected to customer relationship management. The paper presents results of three consecutive researches devoted to issues of customer relationship management. The first two from 2008 and 2010 were conducted as quantitative ones; the one from 2009 had qualitative nature. The respondents were representatives of particular companies. The means for data collection was provided by ReLa system. We will focus on individual attributes of lifetime value of a customer, and relate them to approaches of authors mentioned in introduction. Based on the qualitative research data, the paper focuses on individual customer lifetime value parameters. These parameters include: the cost to the customer relationship acquisition and maintenance, profit generated from a particular customer, customer awareness value, the level of preparedness to adopt new products, the value of references and customer loyalty level. For each of these parameters, the paper provides specific recommendations. Moreover, it is possible to learn about the nature of these parameter assessments in the Czech environment.

Modeling of apparent activation energy and lifetime estimation in NAND flash memory

International Nuclear Information System (INIS)

Lee, Kyunghwan; Shin, Hyungcheol; Kang, Myounggon; Hwang, Yuchul

2015-01-01

Misunderstanding apparent activation energy (E aa ) can cause serious error in lifetime predictions. In this paper, the E aa is investigated for sub 20 nm NAND flash memory. In a high-temperature (HT) regime, the interface trap (N it ) recovery mechanism has the greatest impact on the charge loss. However, the values of E aa and E a(Nit) have a wide difference. Also, the lifetime of the device cannot be estimated by the Arrhenius model due to the E aa roll-off behavior. For the first time, we reveal the origin of abnormal characteristics on E aa and derive a mathematical formula for E aa as a function of each E a(mechanism) in NAND flash memory. Using the proposed E aa equation, the accurate lifetime for the device is estimated. (paper)

A general approach to total repair cost limit replacement policies

Directory of Open Access Journals (Sweden)

F. Beichelt

2014-01-01

Full Text Available A common replacement policy for technical systems consists in replacing a system by a new one after its economic lifetime, i.e. at that moment when its long-run maintenance cost rate is minimal. However, the strict application of the economic lifetime does not take into account the individual deviations of maintenance cost rates of single systems from the average cost development. Hence, Beichet proposed the total repair cost limit replacement policy: the system is replaced by a new one as soon as its total repair cost reaches or exceeds a given level. He modelled the repair cost development by functions of the Wiener process with drift. Here the same policy is considered under the assumption that the one-dimensional probability distribution of the process describing the repair cost development is given. In the examples analysed, applying the total repair cost limit replacement policy instead of the economic life-time leads to cost savings of between 4% and 30%. Finally, it is illustrated how to include the reliability aspect into the policy.

A simple shape-free model for pore-size estimation with positron annihilation lifetime spectroscopy

International Nuclear Information System (INIS)

Wada, Ken; Hyodo, Toshio

2013-01-01

Positron annihilation lifetime spectroscopy is one of the methods for estimating pore size in insulating materials. We present a shape-free model to be used conveniently for such analysis. A basic model in classical picture is modified by introducing a parameter corresponding to an effective size of the positronium (Ps). This parameter is adjusted so that its Ps-lifetime to pore-size relation merges smoothly with that of the well-established Tao-Eldrup model (with modification involving the intrinsic Ps annihilation rate) applicable to very small pores. The combined model, i.e., modified Tao-Eldrup model for smaller pores and the modified classical model for larger pores, agrees surprisingly well with the quantum-mechanics based extended Tao-Eldrup model, which deals with Ps trapped in and thermally equilibrium with a rectangular pore.

A simple shape-free model for pore-size estimation with positron annihilation lifetime spectroscopy

Science.gov (United States)

Wada, Ken; Hyodo, Toshio

2013-06-01

Positron annihilation lifetime spectroscopy is one of the methods for estimating pore size in insulating materials. We present a shape-free model to be used conveniently for such analysis. A basic model in classical picture is modified by introducing a parameter corresponding to an effective size of the positronium (Ps). This parameter is adjusted so that its Ps-lifetime to pore-size relation merges smoothly with that of the well-established Tao-Eldrup model (with modification involving the intrinsic Ps annihilation rate) applicable to very small pores. The combined model, i.e., modified Tao-Eldrup model for smaller pores and the modified classical model for larger pores, agrees surprisingly well with the quantum-mechanics based extended Tao-Eldrup model, which deals with Ps trapped in and thermally equilibrium with a rectangular pore.

Mathematical Model of Lifetime Duration at Insulation of Electrical Machines

Directory of Open Access Journals (Sweden)

Mihaela Răduca

2009-10-01

Full Text Available Abstract. This paper present a mathematical model of lifetime duration at hydro generator stator winding insulation when at hydro generator can be appear the damage regimes. The estimation to make by take of the programming and non-programming revisions, through the introduction and correlation of the new defined notions.

Real-time monitoring of luminescent lifetime changes of PtOEP oxygen sensing film with LED/photodiode-based time-domain lifetime device.

Science.gov (United States)

Ji, Shaomin; Wu, Wanhua; Wu, Yubo; Zhao, Taiyang; Zhou, Fuke; Yang, Yubin; Zhang, Xin; Liang, Xiaofen; Wu, Wenting; Chi, Lina; Wang, Zhonggang; Zhao, Jianzhang

2009-05-01

A cost-effective LED/photodiode(PD)-based time-domain luminescent lifetime measuring device with rugged electronics and simplified algorithms was assembled and successfully used to characterize oxygen sensing films, by continuously monitoring phosphorescence lifetime changes of phosphorescent platinum octaethylporphyrin (PtOEP) in cardo poly(aryl ether ketone) polymer (IMPEK-C) vs. variation of the oxygen partial pressure in a gas mixture (O(2)/N(2)). The results determined by both phosphorescence lifetime and intensity monitoring were compared and the lifetime mode gave results which are in good agreement with the intensity mode. The lifetime-based linear Stern-Volmer plot indicates that the PtOEP molecules are nearly homogeneously distributed in the sensing film. The phosphorescent lifetime of the PtOEP film changes from 75 micros in neat N(2) to less than 2 micros in neat O(2). The sensing system (by combination of the PtOEP sensing film with the home-assembled lifetime device) gives a high lifetime-based O(2) sensing resolution, e.g. about 2 micros Torr(-1) for low O(2) concentration (below 3.5% O(2), V/V). This feasible lifetime device configuration is affordable to most sensor laboratories and the device may facilitate the study of O(2) sensing material with the continuous lifetime monitoring method.

Cost Effectiveness of Childhood Cochlear Implantation and Deaf Education in Nicaragua: A Disability Adjusted Life Year Model.

Science.gov (United States)

Saunders, James E; Barrs, David M; Gong, Wenfeng; Wilson, Blake S; Mojica, Karen; Tucci, Debara L

2015-09-01

Cochlear implantation (CI) is a common intervention for severe-to-profound hearing loss in high-income countries, but is not commonly available to children in low resource environments. Owing in part to the device costs, CI has been assumed to be less economical than deaf education for low resource countries. The purpose of this study is to compare the cost effectiveness of the two interventions for children with severe-to-profound sensorineural hearing loss (SNHL) in a model using disability adjusted life years (DALYs). Cost estimates were derived from published data, expert opinion, and known costs of services in Nicaragua. Individual costs and lifetime DALY estimates with a 3% discounting rate were applied to both two interventions. Sensitivity analysis was implemented to evaluate the effect on the discounted cost of five key components: implant cost, audiology salary, speech therapy salary, number of children implanted per year, and device failure probability. The costs per DALY averted are $5,898 and $5,529 for CI and deaf education, respectively. Using standards set by the WHO, both interventions are cost effective. Sensitivity analysis shows that when all costs set to maximum estimates, CI is still cost effective. Using a conservative DALY analysis, both CI and deaf education are cost-effective treatment alternatives for severe-to-profound SNHL. CI intervention costs are not only influenced by the initial surgery and device costs but also by rehabilitation costs and the lifetime maintenance, device replacement, and battery costs. The major CI cost differences in this low resource setting were increased initial training and infrastructure costs, but lower medical personnel and surgery costs.

Cost-effectiveness of human papillomavirus vaccination and cervical cancer screening in Thailand.

Science.gov (United States)

Sharma, M; Ortendahl, J; van der Ham, E; Sy, S; Kim, J J

2012-01-01

To assess the health and economic outcomes of various screening and vaccination strategies for cervical cancer prevention. Cost-effectiveness analysis from a societal perspective. Thailand. Females aged 9 years and older. Using a mathematical model of human papillomavirus (HPV) infection and cervical cancer, calibrated to epidemiological data from Thailand, we estimated the cost-effectiveness of pre-adolescent HPV vaccination, screening [visual inspection with acetic acid (VIA), HPV DNA testing, and cytology] between one and five times per lifetime in adulthood, and combined pre-adolescent vaccination and screening. Vaccine efficacy, coverage, cost, and screening frequency were varied in sensitivity analyses. Incremental cost-effectiveness ratios, expressed as cost per year of life saved (YLS). Assuming lifelong efficacy and 80% coverage, pre-adolescent HPV vaccination alone was projected to reduce the lifetime risk of cervical cancer by 55%, which was greater than any strategy of screening alone. When cost per vaccinated girl was I$10 (approximately $2 per dose) or less, HPV vaccination alone was cost saving. Pre-adolescent vaccination and HPV DNA testing five times per lifetime, starting at age 35 years, reduced the lifetime cervical cancer risk by 70%, and had a cost-effectiveness ratio less than Thailand's GDP per capita (I$8100), provided the cost per vaccinated girl was I$200 or less. Low cost pre-adolescent HPV vaccination followed by HPV screening five times per lifetime is an efficient strategy for Thailand. Costs may need to be lower, however, for this strategy to be affordable. If vaccination is not feasible, HPV DNA testing five times per lifetime is efficient. © 2011 The Authors BJOG An International Journal of Obstetrics and Gynaecology © 2011 RCOG.

The Cost-Effectiveness of Dual Mobility Implants for Primary Total Hip Arthroplasty: A Computer-Based Cost-Utility Model.

Science.gov (United States)

Barlow, Brian T; McLawhorn, Alexander S; Westrich, Geoffrey H

2017-05-03

Dislocation remains a clinically important problem following primary total hip arthroplasty, and it is a common reason for revision total hip arthroplasty. Dual mobility (DM) implants decrease the risk of dislocation but can be more expensive than conventional implants and have idiosyncratic failure mechanisms. The purpose of this study was to investigate the cost-effectiveness of DM implants compared with conventional bearings for primary total hip arthroplasty. Markov model analysis was conducted from the societal perspective with use of direct and indirect costs. Costs, expressed in 2013 U.S. dollars, were derived from the literature, the National Inpatient Sample, and the Centers for Medicare & Medicaid Services. Effectiveness was expressed in quality-adjusted life years (QALYs). The model was populated with health state utilities and state transition probabilities derived from previously published literature. The analysis was performed for a patient's lifetime, and costs and effectiveness were discounted at 3% annually. The principal outcome was the incremental cost-effectiveness ratio (ICER), with a willingness-to-pay threshold of $100,000/QALY. Sensitivity analyses were performed to explore relevant uncertainty. In the base case, DM total hip arthroplasty showed absolute dominance over conventional total hip arthroplasty, with lower accrued costs ($39,008 versus $40,031 U.S. dollars) and higher accrued utility (13.18 versus 13.13 QALYs) indicating cost-savings. DM total hip arthroplasty ceased being cost-saving when its implant costs exceeded those of conventional total hip arthroplasty by $1,023, and the cost-effectiveness threshold for DM implants was $5,287 greater than that for conventional implants. DM was not cost-effective when the annualized incremental probability of revision from any unforeseen failure mechanism or mechanisms exceeded 0.29%. The probability of intraprosthetic dislocation exerted the most influence on model results. This model

A lifetime prediction method for LEDs considering mission profiles

DEFF Research Database (Denmark)

Qu, Xiaohui; Wang, Huai; Zhan, Xiaoqing

2016-01-01

and to benchmark the cost-competitiveness of different lighting technologies. The existing lifetime data released by LED manufacturers or standard organizations are usually applicable only for specific temperature and current levels. Significant lifetime discrepancies may be observed in field operations due...... to the varying operational and environmental conditions during the entire service time (i.e., mission profiles). To overcome the challenge, this paper proposes an advanced lifetime prediction method, which takes into account the field operation mission profiles and the statistical properties of the life data...

Estimating the long-term effects of in vitro fertilization in Greece: an analysis based on a lifetime-investment model

Directory of Open Access Journals (Sweden)

Fragoulakis V

2013-06-01

Full Text Available Vassilis Fragoulakis, Nikolaos ManiadakisNational School of Public Health, Department of Health Services Management, Athens, GreeceObjective: To quantify the economic effects of a child conceived by in vitro fertilization (IVF in terms of net tax revenue from the state's perspective in Greece.Methods: Based on previous international experience, a mathematical model was developed to assess the lifetime productivity of a single individual and his/her lifetime transactions with governmental agencies. The model distinguished among three periods in the economic life cycle of an individual: (1 early life, when the government primarily contributes resources through child tax credits, health care, and educational expenses; (2 employment, when individuals begin returning resources through taxes; and (3 retirement, when the government expends additional resources on pensions and health care. The cost of a live birth with IVF was based on the modification of a previously published model developed by the authors. All outcomes were discounted at a 3% discount rate. The data inputs – namely, the economic or demographic variables – were derived from the National Statistical Secretariat of Greece and other relevant sources. To deal with uncertainty, bias-corrected uncertainty intervals (UIs were calculated based on 5000 Monte Carlo simulations. In addition, to examine the robustness of our results, other one-way sensitivity analyses were also employed.Results: The cost of IVF per birth was estimated at €17,015 (95% UI: €13,932–€20,200. The average projected income generated by an individual throughout his/her productive life was €258,070 (95% UI: €185,376–€339,831. In addition, his/her life tax contribution was estimated at €133,947 (95% UI: €100,126–€177,375, while the discounted governmental expenses for elderly and underage individuals were €67,624 (95% UI: €55,211–€83,930. Hence, the net present value of IVF was €60

Fuel Cell/ Super-capacitor power management system assessment and Lifetime Cost study in a 500kVA UPS

Directory of Open Access Journals (Sweden)

Imen Ben Amira

2018-03-01

Full Text Available A 500 KVA Uninterruptible power supply (UPS using Fuel Cells (FC and super-capacitors (SCs was studied with the worst case of 10 minutes and eight hours of interruption per day. A power management system was established to control the FC and the SCs in order to extract the hybridization benefits with a comparison between a Proton exchange membrane FC (PEMFC working alone and another combined with SCs. Moreover, possible FC degradations were discussed. The start/stop cycling, the high-power loads and load changes degradations were taken into consideration in order to estimate the FC lifetime span using a prediction formula. Besides, the FC costs were studied to estimate the best average cost. Finally, the SCs filter constant time and their charging currents were revealed.

QUASARS ARE NOT LIGHT BULBS: TESTING MODELS OF QUASAR LIFETIMES WITH THE OBSERVED EDDINGTON RATIO DISTRIBUTION

International Nuclear Information System (INIS)

Hopkins, Philip F.; Hernquist, Lars

2009-01-01

We use the observed distribution of Eddington ratios as a function of supermassive black hole (BH) mass to constrain models of quasar/active galactic nucleus (AGN) lifetimes and light curves. Given the observed (well constrained) AGN luminosity function, a particular model for AGN light curves L(t) or, equivalently, the distribution of AGN lifetimes (time above a given luminosity t(>L)) translates directly and uniquely (without further assumptions) to a predicted distribution of Eddington ratios at each BH mass. Models for self-regulated BH growth, in which feedback produces a self-regulating 'decay' or 'blowout' phase after the AGN reaches some peak luminosity/BH mass and begins to expel gas and shut down accretion, make specific predictions for the light curves/lifetimes, distinct from, e.g., the expected distribution if AGN simply shut down by gas starvation (without feedback) and very different from the prediction of simple phenomenological 'light bulb' scenarios. We show that the present observations of the Eddington ratio distribution, spanning nearly 5 orders of magnitude in Eddington ratio, 3 orders of magnitude in BH mass, and redshifts z = 0-1, agree well with the predictions of self-regulated models, and rule out phenomenological 'light bulb' or pure exponential models, as well as gas starvation models, at high significance (∼5σ). We also compare with observations of the distribution of Eddington ratios at a given AGN luminosity, and find similar good agreement (but show that these observations are much less constraining). We fit the functional form of the quasar lifetime distribution and provide these fits for use, and show how the Eddington ratio distributions place precise, tight limits on the AGN lifetimes at various luminosities, in agreement with model predictions. We compare with independent estimates of episodic lifetimes and use this to constrain the shape of the typical AGN light curve, and provide simple analytic fits to these for use in

Cost-Effectiveness of Intensive versus Standard Blood-Pressure Control.

Science.gov (United States)

Bress, Adam P; Bellows, Brandon K; King, Jordan B; Hess, Rachel; Beddhu, Srinivasan; Zhang, Zugui; Berlowitz, Dan R; Conroy, Molly B; Fine, Larry; Oparil, Suzanne; Morisky, Donald E; Kazis, Lewis E; Ruiz-Negrón, Natalia; Powell, Jamie; Tamariz, Leonardo; Whittle, Jeff; Wright, Jackson T; Supiano, Mark A; Cheung, Alfred K; Weintraub, William S; Moran, Andrew E

2017-08-24

In the Systolic Blood Pressure Intervention Trial (SPRINT), adults at high risk for cardiovascular disease who received intensive systolic blood-pressure control (target, control (target, costs associated with intensive control versus standard control. We used a microsimulation model to apply SPRINT treatment effects and health care costs from national sources to a hypothetical cohort of SPRINT-eligible adults. The model projected lifetime costs of treatment and monitoring in patients with hypertension, cardiovascular disease events and subsequent treatment costs, treatment-related risks of serious adverse events and subsequent costs, and quality-adjusted life-years (QALYs) for intensive control versus standard control of systolic blood pressure. We determined that the mean number of QALYs would be 0.27 higher among patients who received intensive control than among those who received standard control and would cost approximately $47,000 more per QALY gained if there were a reduction in adherence and treatment effects after 5 years; the cost would be approximately $28,000 more per QALY gained if the treatment effects persisted for the remaining lifetime of the patient. Most simulation results indicated that intensive treatment would be cost-effective (51 to 79% below the willingness-to-pay threshold of $50,000 per QALY and 76 to 93% below the threshold of $100,000 per QALY), regardless of whether treatment effects were reduced after 5 years or persisted for the remaining lifetime. In this simulation study, intensive systolic blood-pressure control prevented cardiovascular disease events and prolonged life and did so at levels below common willingness-to-pay thresholds per QALY, regardless of whether benefits were reduced after 5 years or persisted for the patient's remaining lifetime. (Funded by the National Heart, Lung, and Blood Institute and others; SPRINT ClinicalTrials.gov number, NCT01206062 .).

Classification of customer lifetime value models using Markov chain

Science.gov (United States)

Permana, Dony; Pasaribu, Udjianna S.; Indratno, Sapto W.; Suprayogi

2017-10-01

A firm’s potential reward in future time from a customer can be determined by customer lifetime value (CLV). There are some mathematic methods to calculate it. One method is using Markov chain stochastic model. Here, a customer is assumed through some states. Transition inter the states follow Markovian properties. If we are given some states for a customer and the relationships inter states, then we can make some Markov models to describe the properties of the customer. As Markov models, CLV is defined as a vector contains CLV for a customer in the first state. In this paper we make a classification of Markov Models to calculate CLV. Start from two states of customer model, we make develop in many states models. The development a model is based on weaknesses in previous model. Some last models can be expected to describe how real characters of customers in a firm.

German EstSmoke: estimating adult smoking-related costs and consequences of smoking cessation for Germany.

Science.gov (United States)

Sonntag, Diana; Gilbody, Simon; Winkler, Volker; Ali, Shehzad

2018-01-01

We compared predicted life-time health-care costs for current, never and ex-smokers in Germany under the current set of tobacco control polices. We compared these economic consequences of the current situation with an alternative in which Germany were to implement more comprehensive tobacco control policies consistent with the World Health Organization (WHO) Framework Convention for Tobacco Control (FCTC) guidelines. German EstSmoke, an adapted version of the UK EstSmoke simulation model, applies the Markov modelling approach. Transition probabilities for (re-)currence of smoking-related diseases were calculated from large German disease-specific registries and the German Health Update (GEDA 2010). Estimations of both health-care costs and effect sizes of smoking cessation policies were taken from recent German studies and discounted at 3.5%/year. Germany. German population of prevalent current, never and ex-smokers in 2009. Life-time cost and outcomes in current, never and ex-smokers. If tobacco control policies are not strengthened, the German smoking population will incur €41.56 billion life-time excess costs compared with never smokers. Implementing tobacco control policies consistent with WHO FCTC guidelines would reduce the difference of life-time costs between current smokers and ex-smokers by at least €1.7 billion. Modelling suggests that the life-time healthcare costs of people in Germany who smoke are substantially greater than those of people who have never smoked. However, more comprehensive tobacco control policies could reduce health-care expenditures for current smokers by at least 4%. © 2017 Society for the Study of Addiction.

Theoretical calculations of positron lifetimes for metal oxides

International Nuclear Information System (INIS)

Mizuno, Masataka; Araki, Hideki; Shirai, Yasuharu

2004-01-01

Our recent positron lifetime measurements for metal oxides suggest that positron lifetimes of bulk state in metal oxides are shorter than previously reported values. We have performed theoretical calculations of positron lifetimes for bulk and vacancy states in MgO and ZnO using first-principles electronic structure calculations and discuss the validity of positron lifetime calculations for insulators. By comparing the calculated positron lifetimes to the experimental values, it wa found that the semiconductor model well reproduces the experimental positron lifetime. The longer positron lifetime previously reported can be considered to arise from not only the bulk but also from the vacancy induced by impurities. In the case of cation vacancy, the calculated positron lifetime based on semiconductor model is shorter than the experimental value, which suggests that the inward relaxation occurs around the cation vacancy trapping the positron. (author)

Fuel cycle model and the cost of a recycling thorium in the CANDU reactor

International Nuclear Information System (INIS)

Choi, Hangbok; Park, Chang Je

2005-01-01

The dry process fuel technology has a high proliferation-resistance, which allows applications not only to the existing but also to the future nuclear fuel cycle systems. In this study, the homogeneous ThO 2 -UO 2 recycling fuel cycle in a Canada deuterium uranium (CANDU) reactor was assessed for a fuel cycle cost evaluation. A series of parametric calculations were performed for the uranium fraction, enrichment of the initial uranium fuel, and the fission product removal rated of the recycled fuel. The fuel cycle cost was estimated by the levelized lifetime cost model provided by the Organization for Economic Cooperation and Development/Nuclear Energy Agency. Though it is feasible to recycle the homogeneous ThO 2 -UO 2 fuel in the CANDU reactor from the viewpoint of a mass balance, the recycling fuel cycle cost is much higher than the conventional natural uranium fuel cycle cost for most cases due to the high fuel fabrication cost. (author)

The direct cost of traumatic secretion transfer in hermaphroditic land snails: individuals stabbed with a love dart decrease lifetime fecundity.

Science.gov (United States)

Kimura, Kazuki; Chiba, Satoshi

2015-04-07

Several taxa of simultaneously hermaphroditic land snails exhibit a conspicuous mating behaviour, the so-called shooting of love darts. During mating, such land snail species transfer a specific secretion by stabbing a mating partner's body with the love dart. It has been shown that sperm donors benefit from this traumatic secretion transfer, because the secretions manipulate the physiology of a sperm recipient and increase the donors' fertilization success. However, it is unclear whether reception of dart shooting is costly to the recipients. Therefore, the effect of sexual conflict and antagonistic arms races on the evolution of traumatic secretion transfer in land snails is still controversial. To examine this effect, we compared lifetime fecundity and longevity between the individuals that received and did not receive dart shooting from mating partners in Bradybaena pellucida. Our experiments showed that the dart-receiving snails suffered reduction in lifetime fecundity and longevity. These results suggest that the costly mating behaviour, dart shooting, generates conflict between sperm donors and recipients and that sexually antagonistic arms races have contributed to the diversification of the morphological and behavioural traits relevant to dart shooting. Our findings also support theories suggesting a violent escalation of sexual conflict in hermaphroditic animals. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Long-term cost-effectiveness of disease management in systolic heart failure.

Science.gov (United States)

Miller, George; Randolph, Stephen; Forkner, Emma; Smith, Brad; Galbreath, Autumn Dawn

2009-01-01

Although congestive heart failure (CHF) is a primary target for disease management programs, previous studies have generated mixed results regarding the effectiveness and cost savings of disease management when applied to CHF. We estimated the long-term impact of systolic heart failure disease management from the results of an 18-month clinical trial. We used data generated from the trial (starting population distributions, resource utilization, mortality rates, and transition probabilities) in a Markov model to project results of continuing the disease management program for the patients' lifetimes. Outputs included distribution of illness severity, mortality, resource consumption, and the cost of resources consumed. Both cost and effectiveness were discounted at a rate of 3% per year. Cost-effectiveness was computed as cost per quality-adjusted life year (QALY) gained. Model results were validated against trial data and indicated that, over their lifetimes, patients experienced a lifespan extension of 51 days. Combined discounted lifetime program and medical costs were $4850 higher in the disease management group than the control group, but the program had a favorable long-term discounted cost-effectiveness of $43,650/QALY. These results are robust to assumptions regarding mortality rates, the impact of aging on the cost of care, the discount rate, utility values, and the targeted population. Estimation of the clinical benefits and financial burden of disease management can be enhanced by model-based analyses to project costs and effectiveness. Our results suggest that disease management of heart failure patients can be cost-effective over the long term.

Quantum lifetime in electron storage rings

International Nuclear Information System (INIS)

Chao, A.W.

1977-02-01

One of the mechanisms which contribute to beam lifetime in electron storage rings is the quantum emission of energetic photons causing particles to be lost from the rf bucket. This quantum lifetime is among other things important in defining the required aperture in a storage ring. An approximate expression of quantum lifetime, predicted by a one-dimensional model which takes into account only the betatron motion, has been used in most storage ring designs. If the beam is aperture-limited at a position with nonzero dispersion, both the betatron and synchrotron motions have to be included and a two-dimensional model must be used. An exact expression of quantum lifetime for the one-dimensional case and an approximate expression for the two-dimensional case are given

Quantum lifetime in electron storage rings

International Nuclear Information System (INIS)

Chao, A.W.

1977-01-01

One of the mechanisms which contributes to beam lifetime in electron storage rings is the quantum emission of energetic photons causing particles to be lost from the rf bucket. This quantum lifetime is among other things important in defining the required aperture in a storage ring. An approximate expression of quantum lifetime, predicted by a one-dimensional model which takes into account only the betatron motion, has been used in most storage ring designs. If the beam is aperture-limited at a position with nonzero dispersion, both the betatron and synchrotron motions have to be included, and a two-dimensional model must be used. An exact expression of quantum lifetime for the one-dimensional case and an approximate expression for the two-dimensional case are given

A preliminary model for estimating the first wall lifetime of a fusion reactor

International Nuclear Information System (INIS)

Daenner, W.

1975-02-01

The estimation of the first wall lifetime is a necessary basis for predicting the availability of a fusion power plant. In order to do this, an analytical model was prepared and programmed for the computer which calculates the temperature and stress load of the first wall from the principal design parameters and quotes them against the relevant material properties. Neither the analytical model nor the information about the material performance is yet complete so that the answers obtained from the program are very preliminary. This situation is underlined by the results of sample calculations performed for the CTRD blanket module cell. The results obtained for vanadium and vanadium alloys show a strong dependence of the lifetime on the irradiation creep and the ductility of these materials. Completion of this model is envisaged as soon as the missing information becomes available. (orig.) [de

Tobacco retail outlet restrictions: health and cost impacts from multistate life-table modelling in a national population.

Science.gov (United States)

Pearson, Amber L; Cleghorn, Christine L; van der Deen, Frederieke S; Cobiac, Linda J; Kvizhinadze, Giorgi; Nghiem, Nhung; Blakely, Tony; Wilson, Nick

2016-09-22

Since there is some evidence that the density and distribution of tobacco retail outlets may influence smoking behaviours, we aimed to estimate the impacts of 4 tobacco outlet reduction interventions in a country with a smoke-free goal: New Zealand (NZ). A multistate life-table model of 16 tobacco-related diseases, using national data by sex, age and ethnicity, was used to estimate quality-adjusted life years (QALYs) gained and net costs over the remainder of the 2011 NZ population's lifetime. The outlet reduction interventions assumed that increased travel costs can be operationalised as equivalent to price increases in tobacco. All 4 modelled interventions led to reductions of >89% of current tobacco outlets after the 10-year phase-in process. The most effective intervention limited sales to half of liquor stores (and nowhere else) at 129 000 QALYs gained over the lifetime of the population (95% UI: 74 100 to 212 000, undiscounted). The per capita QALY gains were up to 5 times greater for Māori (indigenous population) compared to non-Māori. All interventions were cost-saving to the health system, with the largest saving for the liquor store only intervention: US$1.23 billion (95% UI: $0.70 to $2.00 billion, undiscounted). These tobacco outlet reductions reduced smoking prevalence, achieved health gains and saved health system costs. Effects would be larger if outlet reductions have additional spill-over effects (eg, smoking denormalisation). While these interventions were not as effective as tobacco tax increases (using the same model), these and other strategies could be combined to maximise health gain and to maximise cost-savings to the health system. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

LHCb: Measurement of $b$-hadron lifetimes at LHCb

CERN Multimedia

Amhis, Y

2014-01-01

Lifetimes are among the most fundamental properties of elementary particles. Precision Measurements of $b$-hadron lifetimes are an important tool to test theoretical models such as HQET. These models allow to predict various observables related to B-mixing. Using data collected during Run 1 at the LHC, LHCb measured the lifetime of B-decays including a $J/\\psi$ in the final state.

Parallel excitation-emission multiplexed fluorescence lifetime confocal microscopy for live cell imaging.

Science.gov (United States)

Zhao, Ming; Li, Yu; Peng, Leilei

2014-05-05

We present a novel excitation-emission multiplexed fluorescence lifetime microscopy (FLIM) method that surpasses current FLIM techniques in multiplexing capability. The method employs Fourier multiplexing to simultaneously acquire confocal fluorescence lifetime images of multiple excitation wavelength and emission color combinations at 44,000 pixels/sec. The system is built with low-cost CW laser sources and standard PMTs with versatile spectral configuration, which can be implemented as an add-on to commercial confocal microscopes. The Fourier lifetime confocal method allows fast multiplexed FLIM imaging, which makes it possible to monitor multiple biological processes in live cells. The low cost and compatibility with commercial systems could also make multiplexed FLIM more accessible to biological research community.

Comparative cost-effectiveness of Option B+ for prevention of mother to child transmission of HIV in Malawi: Mathematical modelling study

Science.gov (United States)

Tweya, Hannock; Keiser, Olivia; Haas, Andreas D.; Tenthani, Lyson; Phiri, Sam; Egger, Matthias; Estill, Janne

2016-01-01

Objective To estimate the cost-effectiveness of prevention of mother to child transmission (MTCT) of HIV with lifelong antiretroviral therapy (ART) for pregnant and breastfeeding women (‘Option B+’) compared to ART during pregnancy or breastfeeding only unless clinically indicated (‘Option B’). Design Mathematical modelling study of first and second pregnancy, informed by data from the Malawi Option B+ programme. Methods Individual-based simulation model. We simulated cohorts of 10,000 women and their infants during two subsequent pregnancies, including the breastfeeding period, with either Option B+ or B. We parameterised the model with data from the literature and by analysing programmatic data. We compared total costs of ante-natal and post-natal care, and lifetime costs and disability-adjusted life-years (DALYs) of the infected infants between Option B+ and Option B. Results During the first pregnancy, 15% of the infants born to HIV-infected mothers acquired the infection. With Option B+, 39% of the women were on ART at the beginning of the second pregnancy, compared to 18% with Option B. For second pregnancies, the rates MTCT were 11.3% with Option B+ and 12.3% with Option B. The incremental cost-effectiveness ratio comparing the two options ranged between about US$ 500 and US$ 1300 per DALY averted. Conclusion Option B+ prevents more vertical transmissions of HIV than Option B, mainly because more women are already on ART at the beginning of the next pregnancy. Option B+ is a cost-effective strategy for PMTCT if the total future costs and lost lifetime of the infected infants are taken into account. PMID:26691682

Wind Turbine Blade Life-Time Assessment Model for Preventive Planning of Operation and Maintenance

Directory of Open Access Journals (Sweden)

Mihai Florian

2015-09-01

Full Text Available Out of the total wind turbine failure events, blade damage accounts for a substantial part, with some studies estimating it at around 23%. Current operation and maintenance (O&M practices typically make use of corrective type maintenance as the basic approach, implying high costs for repair and replacement activities as well as large revenue losses, mainly in the case of offshore wind farms. The recent development and evolution of condition monitoring techniques, as well as the fact that an increasing number of installed turbines are equipped with online monitoring systems, offers a large amount of information on the blades structural health to the decision maker. Further, inspections of the blades are often performed in connection with service. In light of the obtained information, a preventive type of maintenance becomes feasible, with the potential of predicting the blades remaining life to support O&M decisions for avoiding major failure events. The present paper presents a fracture mechanics based model for estimating the remaining life of a wind turbine blade, focusing on the crack propagation in the blades adhesive joints. A generic crack propagation model is built in Matlab based on a Paris law approach. The model is used within a risk-based maintenance decision framework to optimize maintenance planning for the blades lifetime.

A simple model for skewed species-lifetime distributions

KAUST Repository

Murase, Yohsuke

2010-06-11

A simple model of a biological community assembly is studied. Communities are assembled by successive migrations and extinctions of species. In the model, species are interacting with each other. The intensity of the interaction between each pair of species is denoted by an interaction coefficient. At each time step, a new species is introduced to the system with randomly assigned interaction coefficients. If the sum of the coefficients, which we call the fitness of a species, is negative, the species goes extinct. The species-lifetime distribution is found to be well characterized by a stretched exponential function with an exponent close to 1/2. This profile agrees not only with more realistic population dynamics models but also with fossil records. We also find that an age-independent and inversely diversity-dependent mortality, which is confirmed in the simulation, is a key mechanism accounting for the distribution. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

Modeling and Application of Customer Lifetime Value in Online Retail

Directory of Open Access Journals (Sweden)

Pavel Jasek

2018-01-01

Full Text Available This article provides an empirical statistical analysis and discussion of the predictive abilities of selected customer lifetime value (CLV models that could be used in online shopping within e-commerce business settings. The comparison of CLV predictive abilities, using selected evaluation metrics, is made on selected CLV models: Extended Pareto/NBD model (EP/NBD, Markov chain model and Status Quo model. The article uses six online store datasets with annual revenues in the order of tens of millions of euros for the comparison. The EP/NBD model has outperformed other selected models in a majority of evaluation metrics and can be considered good and stable for non-contractual relations in online shopping. The implications for the deployment of selected CLV models in practice, as well as suggestions for future research, are also discussed.

PV O&M Cost Model and Cost Reduction

Energy Technology Data Exchange (ETDEWEB)

Walker, Andy

2017-03-15

This is a presentation on PV O&M cost model and cost reduction for the annual Photovoltaic Reliability Workshop (2017), covering estimating PV O&M costs, polynomial expansion, and implementation of Net Present Value (NPV) and reserve account in cost models.

Lifetime modelling for MCrAlY coatings in industrial gas turbine blades

Directory of Open Access Journals (Sweden)

Krukovsky Pavel

2004-01-01

Full Text Available A novel theoretical and experimental approach for lifetime modelling of MCrAlY coatings for stationary gas turbines has been undertaken using the Inverse Problem Solution (IPS technique. With this technique feasible experimental data acquired after a defined experimental time t e are used as input values for the model parameters estimation. In the first stage of the approach a model, based on the oxidation and diffusion processes (Fick's first and second law was assumed, which considers the Al concentration profile across the coating. The measured average Al concentration profiles in the two-phase g+b and g - regions of coating as well as base metal were used as input values for the model parameters estimation and calculational prediction of the long term diffusion and oxidation behavior of the coating was performed. The time, when the b-NiAl phase is completely consumed was assumed as the coating lifetime end. Exposure experiments were carried out with a NiCoCrAlY coating (200 micron thickness with 8% Al in air at 900 °C and 950 °C, currently up to 10000 h. The oxide scale is growing continuously and no other oxides were observed. The average and b-NiAl phase concentration profiles of Al across the coating thickness were determined by electron microprobe and image analysis systems in the initial state after 700 and 10000 h of oxidation. The concentration profile measured after 700 h was used as input values for the model parameters estimation in order to calculate the Al and b-NiAl phase concentration profiles after 10000 h. The computational forecast for 10000 h at 950 °C and 900 °C are in good agreement with the measured data. The approach was applied for NiCoCrAlY (200 micron thickness coating lifetime modelling at 950 °C and 900 °C as well as for different coating thicknesses at 950 °C.

Exits in order: How crowding affects particle lifetimes

Energy Technology Data Exchange (ETDEWEB)

Penington, Catherine J.; Simpson, Matthew J. [School of Mathematical Sciences, Queensland University of Technology, Brisbane (Australia); Baker, Ruth E. [Mathematical Institute, University of Oxford, Radcliffe Observatory Quarter, Woodstock Road, Oxford (United Kingdom)

2016-06-28

Diffusive processes are often represented using stochastic random walk frameworks. The amount of time taken for an individual in a random walk to intersect with an absorbing boundary is a fundamental property that is often referred to as the particle lifetime, or the first passage time. The mean lifetime of particles in a random walk model of diffusion is related to the amount of time required for the diffusive process to reach a steady state. Mathematical analysis describing the mean lifetime of particles in a standard model of diffusion without crowding is well known. However, the lifetime of agents in a random walk with crowding has received much less attention. Since many applications of diffusion in biology and biophysics include crowding effects, here we study a discrete model of diffusion that incorporates crowding. Using simulations, we show that crowding has a dramatic effect on agent lifetimes, and we derive an approximate expression for the mean agent lifetime that includes crowding effects. Our expression matches simulation results very well, and highlights the importance of crowding effects that are sometimes overlooked.

Power management of remote microgrids considering battery lifetime

Science.gov (United States)

Chalise, Santosh

Currently, 20% (1.3 billion) of the world's population still lacks access to electricity and many live in remote areas where connection to the grid is not economical or practical. Remote microgrids could be the solution to the problem because they are designed to provide power for small communities within clearly defined electrical boundaries. Reducing the cost of electricity for remote microgrids can help to increase access to electricity for populations in remote areas and developing countries. The integration of renewable energy and batteries in diesel based microgrids has shown to be effective in reducing fuel consumption. However, the operational cost remains high due to the low lifetime of batteries, which are heavily used to improve the system's efficiency. In microgrid operation, a battery can act as a source to augment the generator or a load to ensure full load operation. In addition, a battery increases the utilization of PV by storing extra energy. However, the battery has a limited energy throughput. Therefore, it is required to provide balance between fuel consumption and battery lifetime throughput in order to lower the cost of operation. This work presents a two-layer power management system for remote microgrids. First layer is day ahead scheduling, where power set points of dispatchable resources were calculated. Second layer is real time dispatch, where schedule set points from the first layer are accepted and resources are dispatched accordingly. A novel scheduling algorithm is proposed for a dispatch layer, which considers the battery lifetime in optimization and is expected to reduce the operational cost of the microgrid. This method is based on a goal programming approach which has the fuel and the battery wear cost as two objectives to achieve. The effectiveness of this method was evaluated through a simulation study of a PV-diesel hybrid microgrid using deterministic and stochastic approach of optimization.

A universal model for languages and cities, and their lifetimes

OpenAIRE

Tuncay, Caglar

2007-01-01

Present human languages display slightly asymmetric log-normal (Gauss) distribution for size [1-3], whereas present cities follow power law (Pareto-Zipf law)[4]. Our model considers the competition between languages and that between cities in terms of growing (multiplicative noise process)[5] and fragmentation [6]; where, relevant parameters are (naturally) different for languages and cities. We consider lifetime distribution for old and living languages and that for old and living cities. We...

NPP lifetime philosophy: the transatlantic difference

International Nuclear Information System (INIS)

Mowry, Christofer

1998-01-01

Fundamental institutional and cultural differences in the transatlantic nuclear power industries, and in particular those between the Nordic countries and the United States, have driven divergent plant life management strategies -strategies resulting in distinctly different plant performance. Recognition of the linkage between three key components of overall Nuclear Power Plant (NPP) performance - yearly O and M costs, safety, and effective plant lifetime -is based on different institutional perspectives. In the Nordic countries, explicit recognition of this linkage has been historically translated into an integrated approach to plant performance. American NPPs, however, have been forced to focus primarily on near term O and M performance and regulatory mandated investment. While Nordic NPPs view capital investment in plant lifetime management and modernization as necessary to avoid declining plant performance and the cost of replacement power, American NPPs exhibit reluctance for such investments due to the difficulty of justifying the associated short-term costs. The diverging histories of two NPPs of the same vintage and design, one in Sweden and one in the United States, exemplify the potential ramifications of these approaches. The Swedish plant continues to operate with excellent performance indicators, while undertaking a comprehensive and long-term modernization program. The American facility is likely to be decommissioned due to unsustainable economic performance. (author)

Cost Model for Digital Preservation: Cost of Digital Migration

Directory of Open Access Journals (Sweden)

Ulla Bøgvad Kejser

2011-03-01

Full Text Available The Danish Ministry of Culture has funded a project to set up a model for costing preservation of digital materials held by national cultural heritage institutions. The overall objective of the project was to increase cost effectiveness of digital preservation activities and to provide a basis for comparing and estimating future cost requirements for digital preservation. In this study we describe an activity-based costing methodology for digital preservation based on the Open Archice Information System (OAIS Reference Model. Within this framework, which we denote the Cost Model for Digital Preservation (CMDP, the focus is on costing the functional entity Preservation Planning from the OAIS and digital migration activities. In order to estimate these costs we have identified cost-critical activities by analysing the functions in the OAIS model and the flows between them. The analysis has been supplemented with findings from the literature, and our own knowledge and experience. The identified cost-critical activities have subsequently been deconstructed into measurable components, cost dependencies have been examined, and the resulting equations expressed in a spreadsheet. Currently the model can calculate the cost of different migration scenarios for a series of preservation formats for text, images, sound, video, geodata, and spreadsheets. In order to verify the model it has been tested on cost data from two different migration projects at the Danish National Archives (DNA. The study found that the OAIS model provides a sound overall framework for the cost breakdown, but that some functions need additional detailing in order to cost activities accurately. Running the two sets of empirical data showed among other things that the model underestimates the cost of manpower-intensive migration projects, while it reinstates an often underestimated cost, which is the cost of developing migration software. The model has proven useful for estimating the

Increasing the lifetime of fuel cell catalysts

NARCIS (Netherlands)

Latsuzbaia, R.

2015-01-01

In this thesis, I discuss a novel idea of fuel cell catalyst regeneration to increase lifetime of the PEM fuel cell electrode/catalyst operation and, therefore, reduce the catalyst costs. As many of the catalyst degradation mechanisms are difficult to avoid, the regeneration is alternative option to

Lifetime oriented maintenance planning in the Netherlands

NARCIS (Netherlands)

Straub, A.

2003-01-01

In this paper we set up a framework for lifetime oriented maintenance planning as an outcome and input for strategic housing stock management. The maintenance planning holds maintenance activities and costs in the longer term. We consider the maintenance planning as a tool to calculate and implement

Alpine ibex males grow large horns at no survival cost for most of their lifetime.

Science.gov (United States)

Toïgo, Carole; Gaillard, Jean-Michel; Loison, Anne

2013-12-01

Large horns or antlers require a high energy allocation to produce and carry both physiological and social reproductive costs. Following the principle of energy allocation that implies trade-offs among fitness components, growing large weapons early in life should thus reduce future growth and survival. Evidence for such costs is ambiguous, however, partly because individual heterogeneity can counterbalance trade-offs. Individuals with larger horns or antlers may be of better quality and thus have a greater capacity to survive. We investigated trade-offs between male early horn growth and future horn growth, baseline mortality, onset of actuarial senescence, and rate of ageing in an Alpine ibex (Capra ibex ibex) population. Horn growth of males in early life was positively correlated to their horn length throughout their entire life. Cohort variation and individual heterogeneity both accounted for among-individual variation in horn length, suggesting both long-lasting effects of early life conditions and individual-specific horn growth trajectories. Early horn growth did not influence annual survival until 12 years of age, indicating that males do not invest in horn growth at survival costs over most of their lifetime. However, males with fast-growing horns early in life tended to have lower survival at very old ages. Individual heterogeneity, along with the particular life-history tactic of male ibex (weak participation to the rut until an old age after which they burn out in high mating investment), are likely to explain why the expected trade-off between horn growth and survival does not show up, at least until very old ages.

LIFETIME LUNG CANCER RISKS ASSOCIATED WITH INDOOR RADON EXPOSURE BASED ON VARIOUS RADON RISK MODELS FOR CANADIAN POPULATION.

Science.gov (United States)

Chen, Jing

2017-04-01

This study calculates and compares the lifetime lung cancer risks associated with indoor radon exposure based on well-known risk models in the literature; two risk models are from joint studies among miners and the other three models were developed from pooling studies on residential radon exposure from China, Europe and North America respectively. The aim of this article is to make clear that the various models are mathematical descriptions of epidemiologically observed real risks in different environmental settings. The risk from exposure to indoor radon is real and it is normal that variations could exist among different risk models even when they were applied to the same dataset. The results show that lifetime risk estimates vary significantly between the various risk models considered here: the model based on the European residential data provides the lowest risk estimates, while models based on the European miners and Chinese residential pooling with complete dosimetry give the highest values. The lifetime risk estimates based on the EPA/BEIR-VI model lie within this range and agree reasonably well with the averages of risk estimates from the five risk models considered in this study. © Crown copyright 2016.

Marginal abatement cost curves for Heavy Duty Vehicles. Background report

Energy Technology Data Exchange (ETDEWEB)

Schroten, A.; Warringa, G.; Bles, M.

2012-09-15

Cost curves were calculated for CO2 abatement technologies for Heavy Duty Vehicles. These curves were elaborated for eight different vehicle categories (six categories of truck and two subcategories), as well as for an 'average' truck and bus. Given that cost curves depend very much on underlying assumptions, the MACH model (Marginal Abatement Costs of Heavy duty vehicles) was developed. This model allows users to enter their own assumptions with respect to parameters like fuel prices and cost and lifetime of individual technologies, with the model then generating new cost curves for the various vehicle categories. This background report contains a description of the model and a summary of the results of several model runs.

An Energy Balanced and Lifetime Extended Routing Protocol for Underwater Sensor Networks.

Science.gov (United States)

Wang, Hao; Wang, Shilian; Zhang, Eryang; Lu, Luxi

2018-05-17

Energy limitation is an adverse problem in designing routing protocols for underwater sensor networks (UWSNs). To prolong the network lifetime with limited battery power, an energy balanced and efficient routing protocol, called energy balanced and lifetime extended routing protocol (EBLE), is proposed in this paper. The proposed EBLE not only balances traffic loads according to the residual energy, but also optimizes data transmissions by selecting low-cost paths. Two phases are operated in the EBLE data transmission process: (1) candidate forwarding set selection phase and (2) data transmission phase. In candidate forwarding set selection phase, nodes update candidate forwarding nodes by broadcasting the position and residual energy level information. The cost value of available nodes is calculated and stored in each sensor node. Then in data transmission phase, high residual energy and relatively low-cost paths are selected based on the cost function and residual energy level information. We also introduce detailed analysis of optimal energy consumption in UWSNs. Numerical simulation results on a variety of node distributions and data load distributions prove that EBLE outperforms other routing protocols (BTM, BEAR and direct transmission) in terms of network lifetime and energy efficiency.

Corneal Collagen Cross-Linking in the Management of Keratoconus in Canada: A Cost-Effectiveness Analysis.

Science.gov (United States)

Leung, Victoria C; Pechlivanoglou, Petros; Chew, Hall F; Hatch, Wendy

2017-08-01

To use patient-level microsimulation models to evaluate the comparative cost-effectiveness of early corneal cross-linking (CXL) and conventional management with penetrating keratoplasty (PKP) when indicated in managing keratoconus in Canada. Cost-utility analysis using individual-based, state-transition microsimulation models. Simulated cohorts of 100 000 individuals with keratoconus who entered each treatment arm at 25 years of age. Fellow eyes were modeled separately. Simulated individuals lived up to a maximum of 110 years. We developed 2 state-transition microsimulation models to reflect the natural history of keratoconus progression and the impact of conventional management with PKP versus CXL. We collected data from the published literature to inform model parameters. We used realistic parameters that maximized the potential costs and complications of CXL, while minimizing those associated with PKP. In each treatment arm, we allowed simulated individuals to move through health states in monthly cycles from diagnosis until death. For each treatment strategy, we calculated the total cost and number of quality-adjusted life years (QALYs) gained. Costs were measured in Canadian dollars. Costs and QALYs were discounted at 5%, converting future costs and QALYs into present values. We used an incremental cost-effectiveness ratio (ICER = difference in lifetime costs/difference in lifetime health outcomes) to compare the cost-effectiveness of CXL versus conventional management with PKP. Lifetime costs and QALYs for CXL were estimated to be Can$5530 (Can$4512, discounted) and 50.12 QALYs (16.42 QALYs, discounted). Lifetime costs and QALYs for conventional management with PKP were Can$2675 (Can$1508, discounted) and 48.93 QALYs (16.09 QALYs, discounted). The discounted ICER comparing CXL to conventional management was Can$9090/QALY gained. Sensitivity analyses revealed that in general, parameter variations did not influence the cost-effectiveness of CXL. CXL is

Comparison of additive (absolute) risk projection models and multiplicative (relative) risk projection models in estimating radiation-induced lifetime cancer risk

International Nuclear Information System (INIS)

Kai, Michiaki; Kusama, Tomoko

1990-01-01

Lifetime cancer risk estimates depend on risk projection models. While the increasing lengths of follow-up observation periods of atomic bomb survivors in Hiroshima and Nagasaki bring about changes in cancer risk estimates, the validity of the two risk projection models, the additive risk projection model (AR) and multiplicative risk projection model (MR), comes into question. This paper compares the lifetime risk or loss of life-expectancy between the two projection models on the basis of BEIR-III report or recently published RERF report. With Japanese cancer statistics the estimates of MR were greater than those of AR, but a reversal of these results was seen when the cancer hazard function for India was used. When we investigated the validity of the two projection models using epidemiological human data and animal data, the results suggested that MR was superior to AR with respect to temporal change, but there was little evidence to support its validity. (author)

HTGR Cost Model Users' Manual

International Nuclear Information System (INIS)

Gandrik, A.M.

2012-01-01

The High Temperature Gas-Cooler Reactor (HTGR) Cost Model was developed at the Idaho National Laboratory for the Next Generation Nuclear Plant Project. The HTGR Cost Model calculates an estimate of the capital costs, annual operating and maintenance costs, and decommissioning costs for a high-temperature gas-cooled reactor. The user can generate these costs for multiple reactor outlet temperatures; with and without power cycles, including either a Brayton or Rankine cycle; for the demonstration plant, first of a kind, or nth of a kind project phases; for a single or four-pack configuration; and for a reactor size of 350 or 600 MWt. This users manual contains the mathematical models and operating instructions for the HTGR Cost Model. Instructions, screenshots, and examples are provided to guide the user through the HTGR Cost Model. This model was design for users who are familiar with the HTGR design and Excel. Modification of the HTGR Cost Model should only be performed by users familiar with Excel and Visual Basic.

Cost Model for Digital Preservation: Cost of Digital Migration

DEFF Research Database (Denmark)

Kejser, Ulla Bøgvad; Nielsen, Anders Bo; Thirifays, Alex

2011-01-01

The Danish Ministry of Culture has funded a project to set up a model for costing preservation of digital materials held by national cultural heritage institutions. The overall objective of the project was to increase cost effectiveness of digital preservation activities and to provide a basis...... for comparing and estimating future cost requirements for digital preservation. In this study we describe an activity-based costing methodology for digital preservation based on the Open Archice Information System (OAIS) Reference Model. Within this framework, which we denote the Cost Model for Digital...... Preservation (CMDP), the focus is on costing the functional entity Preservation Planning from the OAIS and digital migration activities. In order to estimate these costs we have identified cost-critical activities by analysing the functions in the OAIS model and the flows between them. The analysis has been...

A Departmental Cost-Effectiveness Model.

Science.gov (United States)

Holleman, Thomas, Jr.

In establishing a departmental cost-effectiveness model, the traditional cost-effectiveness model was discussed and equipped with a distant and deflation equation for both benefits and costs. Next, the economics of costing was examined and program costing procedures developed. Then, the model construct was described as it was structured around the…

NPP Krsko Lifetime Extension - Business Impact for Hrvatska Elektroprivreda

International Nuclear Information System (INIS)

Vrankic, K.; Krejci, M.; Lebegner, J.

2006-01-01

This paper deals with the analysis of possible business impacts for HEP in the case of NPP Krsko life extension. Due to numerous reasons nuclear power plant life extension of ten to twenty years is a common procedure abroad. Having this practise in mind as well as other circumstances in Croatian and Slovenian electric power system, the extension of NPP Krsko lifetime is considered to be a possible scenario. Foreseeable impacts of this decision are evaluated primarily with consideration of its effect on HEPs projected cash flows, though other aspects will be addressed as well. Preserving a well maintained production facility with an extraordinary operational record and stable, or possibly falling overall production costs seems as a very rational choice. This is particularly true having in mind expected rise of electricity demand and energy prices in the region. Having NPP Krsko in operation beyond 2023 implies that no replacement source for NPP Krsko capacity needs to be built. This means avoiding all costs connected with the construction and operation of the replacement plant, assuming it will be fossil fuelled. Due to the high uncertainty of the future fossil fuel prices, the avoidance of replacement plant operational cost is likely to prove as highly rewarding. It should be kept in mind that avoided costs also include the replacement plant greenhouse gases emission costs, thus further enlarging the list of value adding impacts. The latter is valid anticipating the ratification of the Kyoto protocol and joining the European emission trading scheme. In addition to that, the extension of NPP Krsko lifetime would mean that the majority of costs connected with the decommissioning and final waste disposal can be postponed further down the time line. This will have very positive financial and possibly technological impact. Other value creating effects for HEP that are foreseeable as a consequence of the plant lifetime extension include: maintaining the knowledge of

Atmospheric lifetimes of CFC 11 and CFC 12

International Nuclear Information System (INIS)

Owens, A.J.; Steed, J.M.; Miller, C.; Filkin, D.L.; Jesson, J.P.

1982-01-01

A two-dimensional (2-D) chemical model of the atmosphere is used to investigate the stratospheric removal rates of the chlorofluorocarbons CFC 11 (CFCl 3 ) and CFC 12 (CF 2 Cl 2 ). Assuming equivalent vertical transport rates, one-dimensional (1-D) models are shown to overestimate the atmospheric lifetime of CFC 11 by approx.10% because of their neglect of latitudinal effects. The present Du Pont 1-D and 2-D models have somewhat different effective transport rates and give steady state CFC 11 atmospheric lifetimes of 75 and 60 years, respectively, assuming no tropospheric destructive mechanism. For CFC 12, the corresponding calculated lifetimes are 140 and 120 years

Potential lifetime cost-effectiveness of catheter-based renal sympathetic denervation in patients with resistant hypertension.

Science.gov (United States)

Dorenkamp, Marc; Bonaventura, Klaus; Leber, Alexander W; Boldt, Julia; Sohns, Christian; Boldt, Leif-Hendrik; Haverkamp, Wilhelm; Frei, Ulrich; Roser, Mattias

2013-02-01

Recent studies have demonstrated the safety and efficacy of catheter-based renal sympathetic denervation (RDN) for the treatment of resistant hypertension. We aimed to determine the cost-effectiveness of this approach separately for men and women of different ages. A Markov state-transition model accounting for costs, life-years, quality-adjusted life-years (QALYs), and incremental cost-effectiveness was developed to compare RDN with best medical therapy (BMT) in patients with resistant hypertension. The model ran from age 30 to 100 years or death, with a cycle length of 1 year. The efficacy of RDN was modelled as a reduction in the risk of hypertension-related disease events and death. Analyses were conducted from a payer's perspective. Costs and QALYs were discounted at 3% annually. Both deterministic and probabilistic sensitivity analyses were performed. When compared with BMT, RDN gained 0.98 QALYs in men and 0.88 QALYs in women 60 years of age at an additional cost of €2589 and €2044, respectively. As the incremental cost-effectiveness ratios increased with patient age, RDN consistently yielded more QALYs at lower costs in lower age groups. Considering a willingness-to-pay threshold of €35 000/QALY, there was a 95% probability that RDN would remain cost-effective up to an age of 78 and 76 years in men and women, respectively. Cost-effectiveness was influenced mostly by the magnitude of effect of RDN on systolic blood pressure, the rate of RDN non-responders, and the procedure costs of RDN. Renal sympathetic denervation is a cost-effective intervention for patients with resistant hypertension. Earlier treatment produces better cost-effectiveness ratios.

Reliability-based assessment of polyethylene pipe creep lifetime

International Nuclear Information System (INIS)

Khelif, Rabia; Chateauneuf, Alaa; Chaoui, Kamel

2007-01-01

Lifetime management of underground pipelines is mandatory for safe hydrocarbon transmission and distribution systems. The use of high-density polyethylene tubes subjected to internal pressure, external loading and environmental variations requires a reliability study in order to define the service limits and the optimal operating conditions. In service, the time-dependent phenomena, especially creep, take place during the pipe lifetime, leading to significant strength reduction. In this work, the reliability-based assessment of pipe lifetime models is carried out, in order to propose a probabilistic methodology for lifetime model selection and to determine the pipe safety levels as well as the most important parameters for pipeline reliability. This study is enhanced by parametric analysis on pipe configuration, gas pressure and operating temperature

Reliability-based assessment of polyethylene pipe creep lifetime

Energy Technology Data Exchange (ETDEWEB)

Khelif, Rabia [LaMI-UBP and IFMA, Campus de Clermont-Fd, Les Cezeaux, BP 265, 63175 Aubiere Cedex (France); LR3MI, Departement de Genie Mecanique, Universite Badji Mokhtar, BP 12, Annaba 23000 (Algeria)], E-mail: rabia.khelif@ifma.fr; Chateauneuf, Alaa [LGC-University Blaise Pascal, Campus des Cezeaux, BP 206, 63174 Aubiere Cedex (France)], E-mail: alaa.chateauneuf@polytech.univ-bpclermont.fr; Chaoui, Kamel [LR3MI, Departement de Genie Mecanique, Universite Badji Mokhtar, BP 12, Annaba 23000 (Algeria)], E-mail: chaoui@univ-annaba.org

2007-12-15

Lifetime management of underground pipelines is mandatory for safe hydrocarbon transmission and distribution systems. The use of high-density polyethylene tubes subjected to internal pressure, external loading and environmental variations requires a reliability study in order to define the service limits and the optimal operating conditions. In service, the time-dependent phenomena, especially creep, take place during the pipe lifetime, leading to significant strength reduction. In this work, the reliability-based assessment of pipe lifetime models is carried out, in order to propose a probabilistic methodology for lifetime model selection and to determine the pipe safety levels as well as the most important parameters for pipeline reliability. This study is enhanced by parametric analysis on pipe configuration, gas pressure and operating temperature.

Designer's unified cost model

Science.gov (United States)

Freeman, William T.; Ilcewicz, L. B.; Swanson, G. D.; Gutowski, T.

1992-01-01

A conceptual and preliminary designers' cost prediction model has been initiated. The model will provide a technically sound method for evaluating the relative cost of different composite structural designs, fabrication processes, and assembly methods that can be compared to equivalent metallic parts or assemblies. The feasibility of developing cost prediction software in a modular form for interfacing with state of the art preliminary design tools and computer aided design programs is being evaluated. The goal of this task is to establish theoretical cost functions that relate geometric design features to summed material cost and labor content in terms of process mechanics and physics. The output of the designers' present analytical tools will be input for the designers' cost prediction model to provide the designer with a data base and deterministic cost methodology that allows one to trade and synthesize designs with both cost and weight as objective functions for optimization. The approach, goals, plans, and progress is presented for development of COSTADE (Cost Optimization Software for Transport Aircraft Design Evaluation).

Impacts of PV Array Sizing on PV Inverter Lifetime and Reliability

DEFF Research Database (Denmark)

Sangwongwanich, Ariya; Yang, Yongheng; Sera, Dezso

2017-01-01

. However, oversizing the PV array will increase the loading of PV inverters, which may have undesired influence on the PV inverter lifetime and reliability. In that case, it may result in a negative impact on the overall PV energy cost, due to the increased maintenance for the PV inverters. This paper...... evaluates the lifetime of PV inverters considering the PV array sizing and installation sites, e.g., Denmark and Arizona. The results reveal that the PV array sizing has a considerable impact on the PV inverter lifetime and reliability, especially in Denmark, where the average solar irradiance level...

Effectiveness and cost-effectiveness of an awareness campaign for colorectal cancer: a mathematical modeling study.

Science.gov (United States)

Whyte, Sophie; Harnan, Susan

2014-06-01

A campaign to increase the awareness of the signs and symptoms of colorectal cancer (CRC) and encourage self-presentation to a GP was piloted in two regions of England in 2011. Short-term data from the pilot evaluation on campaign cost and changes in GP attendances/referrals, CRC incidence, and CRC screening uptake were available. The objective was to estimate the effectiveness and cost-effectiveness of a CRC awareness campaign by using a mathematical model which extrapolates short-term outcomes to predict long-term impacts on cancer mortality, quality-adjusted life-years (QALYs), and costs. A mathematical model representing England (aged 30+) for a lifetime horizon was developed. Long-term changes to cancer incidence, cancer stage distribution, cancer mortality, and QALYs were estimated. Costs were estimated incorporating costs associated with delivering the campaign, additional GP attendances, and changes in CRC treatment. Data from the pilot campaign suggested that the awareness campaign caused a 1-month 10 % increase in presentation rates. Based on this, the model predicted the campaign to cost £5.5 million, prevent 66 CRC deaths and gain 404 QALYs. The incremental cost-effectiveness ratio compared to "no campaign" was £13,496 per QALY. Results were sensitive to the magnitude and duration of the increase in presentation rates and to disease stage. The effectiveness and cost-effectiveness of a cancer awareness campaign can be estimated based on short-term data. Such predictions will aid policy makers in prioritizing between cancer control strategies. Future cost-effectiveness studies would benefit from campaign evaluations reporting as follows: data completeness, duration of impact, impact on emergency presentations, and comparison with non-intervention regions.

Impact of generic alendronate cost on the cost-effectiveness of osteoporosis screening and treatment.

Directory of Open Access Journals (Sweden)

Smita Nayak

Full Text Available Since alendronate became available in generic form in the Unites States in 2008, its price has been decreasing. The objective of this study was to investigate the impact of alendronate cost on the cost-effectiveness of osteoporosis screening and treatment in postmenopausal women.Microsimulation cost-effectiveness model of osteoporosis screening and treatment for U.S. women age 65 and older. We assumed screening initiation at age 65 with central dual-energy x-ray absorptiometry (DXA, and alendronate treatment for individuals with osteoporosis; with a comparator of "no screening" and treatment only after fracture occurrence. We evaluated annual alendronate costs of $20 through $800; outcome measures included fractures; nursing home admission; medication adverse events; death; costs; quality-adjusted life-years (QALYs; and incremental cost-effectiveness ratios (ICERs in 2010 U.S. dollars per QALY gained. A lifetime time horizon was used, and direct costs were included. Base-case and sensitivity analyses were performed.Base-case analysis results showed that at annual alendronate costs of $200 or less, osteoporosis screening followed by treatment was cost-saving, resulting in lower total costs than no screening as well as more QALYs (10.6 additional quality-adjusted life-days. When assuming alendronate costs of $400 through $800, screening and treatment resulted in greater lifetime costs than no screening but was highly cost-effective, with ICERs ranging from $714 per QALY gained through $13,902 per QALY gained. Probabilistic sensitivity analyses revealed that the cost-effectiveness of osteoporosis screening followed by alendronate treatment was robust to joint input parameter estimate variation at a willingness-to-pay threshold of $50,000/QALY at all alendronate costs evaluated.Osteoporosis screening followed by alendronate treatment is effective and highly cost-effective for postmenopausal women across a range of alendronate costs, and may be cost

Hepatitis C Treatment Regimens Are Cost-Effective: But Compared With What?

Science.gov (United States)

Mattingly, T Joseph; Slejko, Julia F; Mullins, C Daniel

2017-11-01

Numerous economic models have been published evaluating treatment of chronic hepatitis C virus (HCV) infection, but none provide a comprehensive comparison among new antiviral agents. Evaluate the cost-effectiveness of all recommended therapies for treatment of genotypes 1 and 4 chronic HCV. Using data from clinical trials, observational analyses, and drug pricing databases, Markov decision models were developed for HCV genotypes 1 and 4 to compare all recommended drugs from the perspective of the third-party payer over a 5-, 10-, and 50-year time horizon. A probabilistic sensitivity analysis (PSA) was conducted by assigning distributions for clinical cure, age entering the model, costs for each health state, and quality-adjusted life years (QALYs) for each health state in a Monte Carlo simulation of 10 000 repetitions of the model. In the lifetime model for genotype 1, effects ranged from 18.08 to 18.40 QALYs and total costs ranged from $88 107 to $184 636. The lifetime model of genotype 4 treatments had a range of effects from 18.23 to 18.43 QALYs and total costs ranging from $87 063 to $127 637. Grazoprevir/elbasvir was the optimal strategy followed by velpatasvir/sofosbuvir as the second-best strategy in most simulations for both genotypes 1 and 4, with drug costs and efficacy of grazoprevir/elbasvir as the primary model drivers. Grazoprevir/elbasvir was cost-effective compared with all strategies for genotypes 1 and 4. Effects for all strategies were similar with cost of drug in the initial year driving the results.

Distribution transformer lifetime analysis in the presence of demand response and rooftop PV integration

Directory of Open Access Journals (Sweden)

Behi Behnaz

2017-01-01

Full Text Available Many distribution transformers have already exceeded half of their expected service life of 35 years in the infrastructure of Western Power, the electric distribution company supplying southwest of Western Australia, Australia. Therefore, it is anticipated that a high investment on transformer replacement happens in the near future. However, high renewable integration and demand response (DR are promising resources to defer the investment on infrastructure upgrade and extend the lifetime of transformers. This paper investigates the impact of rooftop photovoltaic (PV integration and customer engagement through DR on the lifetime of transformers in electric distribution networks. To this aim, first, a time series modelling of load, DR and PV is utilised for each year over a planning period. This load model is applied to a typical distribution transformer for which the hot-spot temperature rise is modelled based on the relevant standard. Using this calculation platform, the loss of life and the actual age of distribution transformer are obtained. Then, various scenarios including different levels of PV penetration and DR contribution are examined, and their impacts on the age of transformer are reported. Finally, the equivalent loss of net present value of distribution transformer is formulated and discussed. This formulation gives major benefits to the distribution network planners for analysing the contribution of PV and DR on lifetime extension of the distribution transformer. In addition, the provided model can be utilised in optimal investment analysis to find the best time for the transformer replacement and the associated cost considering PV penetration and DR. The simulation results show that integration of PV and DR within a feeder can significantly extend the lifetime of transformers.

Lifetime of chaotic attractors in a multidimensional laser system

International Nuclear Information System (INIS)

Pando L, C.L.; Cerdeira, H.A.

1995-01-01

We study the lifetimes of chaotic attractors at crises in a multidimensional laser system. This system describes the CO 2 laser with modulated losses and is known as the four-level model. The critical exponents which are related to the lifetimes of the attractors are estimated in terms of the corresponding eigenvalues and the measured characteristic lifetime in the model. The critical exponents in this model and those of its center manifold version are in good agreement. We conjecture that generically in the four-level model the critical exponents are close to 1/2 at crises. In addition, we compare predictions of a simpler and popular model known as the two-level model with those of the above mentioned models. (author). 21 refs, 2 figs, 3 tabs

Management of End-Stage Ankle Arthritis: Cost-Utility Analysis Using Direct and Indirect Costs.

Science.gov (United States)

Nwachukwu, Benedict U; McLawhorn, Alexander S; Simon, Matthew S; Hamid, Kamran S; Demetracopoulos, Constantine A; Deland, Jonathan T; Ellis, Scott J

2015-07-15

Total ankle replacement and ankle fusion are costly but clinically effective treatments for ankle arthritis. Prior cost-effectiveness analyses for the management of ankle arthritis have been limited by a lack of consideration of indirect costs and nonoperative management. The purpose of this study was to compare the cost-effectiveness of operative and nonoperative treatments for ankle arthritis with inclusion of direct and indirect costs in the analysis. Markov model analysis was conducted from a health-systems perspective with use of direct costs and from a societal perspective with use of direct and indirect costs. Costs were derived from the 2012 Nationwide Inpatient Sample (NIS) and expressed in 2013 U.S. dollars; effectiveness was expressed in quality-adjusted life years (QALYs). Model transition probabilities were derived from the available literature. The principal outcome measure was the incremental cost-effectiveness ratio (ICER). In the direct-cost analysis for the base case, total ankle replacement was associated with an ICER of $14,500/QALY compared with nonoperative management. When indirect costs were included, total ankle replacement was both more effective and resulted in $5900 and $800 in lifetime cost savings compared with the lifetime costs following nonoperative management and ankle fusion, respectively. At a $100,000/QALY threshold, surgical management of ankle arthritis was preferred for patients younger than ninety-six years and total ankle replacement was increasingly more cost-effective in younger patients. Total ankle replacement, ankle fusion, and nonoperative management were the preferred strategy in 83%, 12%, and 5% of the analyses, respectively; however, our model was sensitive to patient age, the direct costs of total ankle replacement, the failure rate of total ankle replacement, and the probability of arthritis after ankle fusion. Compared with nonoperative treatment for the management of end-stage ankle arthritis, total ankle

Fiscal Impact of Smoking Cessation in Thailand: A Government Perspective Cost-Benefit Analysis.

Science.gov (United States)

Connolly, Mark P; Kotsopoulos, Nikolaos; Suthipinijtham, Pichaya; Rungruanghiranya, Suthat

2018-04-01

We evaluate the broader public economic consequences of investments in smoking cessation that change lifetime productivity, which can influence future government tax revenue and social transfer costs and health care spending. The analysis applies a government perspective framework for assessing the intergenerational relationships between morbidity and mortality and lifetime tax revenue and social transfers received. Applying smoking prevalence in Thailand, a cohort model was developed for smoker and former smokers to estimate impact on lifetime direct taxes and tobacco taxes paid. Age-specific earnings for males and wage appropriate tax rates were applied to estimate net taxes for smokers and former smokers. Introducing smoking cessation leads to lifetime public economic benefits of THB13 998 to THB43 356 per person depending on the age of introducing smoking cessation. Factoring in the costs of smoking cessation therapy, an average return on investment of 1.35 was obtained indicating fiscal surplus generated for government from the combined effect of increased tax revenues and of averting smoking-attributable health care costs.

Degradation modeling and operational optimization for improving the lifetime of high-temperature PEM (proton exchange membrane) fuel cells

International Nuclear Information System (INIS)

Kim, Jintae; Kim, Minjin; Kang, Taegon; Sohn, Young-Jun; Song, Taewon; Choi, Kyoung Hwan

2014-01-01

High-temperature PEMFCs (proton exchange membrane fuel cells) using PA (phosphoric acid)-doped PBI (polybenzimidazole) membranes have received attention as a potential solution to several of the issues with traditional low-temperature PEMFCs. However, the durability of high-temperature PEMFCs deteriorates rapidly with increasing temperature, although its performance improves. This characteristic makes it difficult to select the proper operating temperature to achieve its target lifetime. In this paper, to resolve this problem, models were developed to predict the performance and durability of the high-temperature PEMFC as a function of operating temperature. The optimal operating temperature was then determined for a variety of lifetimes. Theoretical model to estimate cell performance and empirical model to predict the degradation rate of cell performance were constructed, respectively. The prediction results of the developed models agreed well with the experimental data. From the simulation, we could obtain higher average cell performances by optimizing the operating temperature for the given target lifetime compared to the cell performance at some temperatures determined using an existing rule of thumb. It is expected that the proposed methodologies will lead to the more rapid commercialization of this technology in such applications as stationary and automotive fuel cell systems. - Highlights: • High-temperature PEMFCs (proton exchange membrane fuel cells). • Operational optimization for improving the lifetime. • Development of the degradation modeling for high-temperature PEMFCs

Designers' unified cost model

Science.gov (United States)

Freeman, W.; Ilcewicz, L.; Swanson, G.; Gutowski, T.

1992-01-01

The Structures Technology Program Office (STPO) at NASA LaRC has initiated development of a conceptual and preliminary designers' cost prediction model. The model will provide a technically sound method for evaluating the relative cost of different composite structural designs, fabrication processes, and assembly methods that can be compared to equivalent metallic parts or assemblies. The feasibility of developing cost prediction software in a modular form for interfacing with state-of-the-art preliminary design tools and computer aided design programs is being evaluated. The goal of this task is to establish theoretical cost functions that relate geometric design features to summed material cost and labor content in terms of process mechanics and physics. The output of the designers' present analytical tools will be input for the designers' cost prediction model to provide the designer with a database and deterministic cost methodology that allows one to trade and synthesize designs with both cost and weight as objective functions for optimization. This paper presents the team members, approach, goals, plans, and progress to date for development of COSTADE (Cost Optimization Software for Transport Aircraft Design Evaluation).

Nuclear lifetimes

International Nuclear Information System (INIS)

Caraca, J.M.G.

1976-01-01

The importance of the results obtained in experiments of measurement of lifetimes for a detailed knowledge of nuclear structure is referred. Direct methods of measurement of nuclear lifetimes are described, namely, electronic methods, recoil-distance method, doppler shift atenuation method and blocking-method. A brief reference is made to indirect methods for measurement of life-times

Plant lifetime management and research program

International Nuclear Information System (INIS)

Sakai, K.; Nagayama, M.

1993-01-01

The importance of nuclear power generation has been increasing in Japan. Because the lower generation cost and more stable fuel supply, in comparison with the case of fossil plants, are beneficial to Japan which has scarce natural resources. In addition, nuclear power generation is expected to help reduce carbon dioxide emission which causes global warming. In these circumstances, the safe and stable operations of nuclear power plants are of prime importance, and the frequency of unscheduled shutdown has been kept low in Japan as a result of thorough periodic inspections supported by aging management. This paper covers the development process of the aging management program and related research programs in The Kansai Electric Power Co., Inc. (KEPCO). KEPCO runs 11 nuclear power units (PWR). A Table shows the commencement date of commercial operation and operating hours for each unit. The early plants, such as Mihama-2 Unit, have been operated for more than 100,000 hours and are in the phase of aging management. Accordingly, we have been conducting aging management programs since 1987. in order to identify age-related degradation and work out countermeasures.The aging management programs have ensured safe and stable operation of nuclear power plants. Each result of the lifetime assessment has provided the information which helps establishing maintenance programs. For example, the result of the lifetime assessment has been reflected to the intervals of overhaulings and inspections, and the replacement timing of some components. In the future activities of aging management should be revised and should focus lifetime assessment on components which provoke difficulties in inspections because of high radiation exposure or high inspection cost

The implications of plant design on the life-time costs for nuclear fuel cycle facilities

International Nuclear Information System (INIS)

Macphee, D.S.; Hexter, B.C.; Young, M.P.; Wilson, B.J.

1997-01-01

Utilising the experience gained during many years of design and project management of nuclear plant, BNFL is now approaching the final stages of the construction and commissioning of the Sellafield MOX Plant (SMP) in the UK. The paper uses the SMP project to highlight the benefits of these experiences, in particular addressing the implications of the approach to plant design on life time costs. In addition to providing BNFL with a state of the art, commercial scale MOX fuel fabrication facility, the construction of this 120 tHM/yr facility, which is currently in the advanced stages of commissioning, represents a significant demonstration of the design and project management skills of BNFL Engineering Ltd. As well as meeting the main process requirements, the plant design incorporates the highest standards of safety, together with input from the future plant operators and potential customers. As befits a commercial scale plutonium handling facility, SMP also incorporates material accountancy and security provisions that will meet all international requirements. Design, construction and commissioning of this complex and highly automated plant, has benefited from a totally integrated approach to design and documentation that considers not only project implementation but also overall lifetime costs. In addition, project management techniques, developed over many years of major project construction at Sellafield, have been utilised in order to ensure successful project implementation against a background of significant technical challenge and 'fast track' timescales. (author)

Software Cost-Estimation Model

Science.gov (United States)

Tausworthe, R. C.

1985-01-01

Software Cost Estimation Model SOFTCOST provides automated resource and schedule model for software development. Combines several cost models found in open literature into one comprehensive set of algorithms. Compensates for nearly fifty implementation factors relative to size of task, inherited baseline, organizational and system environment and difficulty of task.

Lifetime Analysis of Rubber Gasket Composed of Methyl Vinyl Silicone Rubber with Low-Temperature Resistance

Directory of Open Access Journals (Sweden)

Young-Doo Kwon

2015-01-01

Full Text Available Most machines and instruments constantly require elastomeric materials like rubber for the purposes of shock absorption, noise attenuation, and sealing. The material properties and accurate lifetime prediction of rubber are closely related to the quality of machines, especially their durability and reliability. The properties of rubber-like elastomers are influenced by ambient conditions, such as temperature, environment, and mechanical load. Moreover, the initial properties of rubber gaskets must be sustained under working conditions to satisfy their required function. Because of its technical merits, as well as its low cost, the highly accelerated life test (HALT is used by many researchers to predict the long-term lifetime of rubber materials. Methyl vinyl silicone rubber (VMQ has recently been adopted to improve the lifetime of automobile radiator gaskets. A four-parameter method of determining the recovery ability of the gaskets was recently published, and two revised methods of obtaining the recovery were proposed for polyacrylate (ACM rubber. The recovery rate curves for VMQ were acquired using the successive zooming genetic algorithm (SZGA. The gasket lifetime for the target recovery (60% of a compressed gasket was computed somewhat differently depending on the selected regression model.

Comparison of economic evaluation methodology for the nuclear plant lifetime extension

International Nuclear Information System (INIS)

Song, T. H.; Jung, I. S.

2003-01-01

In connection with economic evaluation of NPP lifetime management, there are lots of methodologies such as present worth calculation, Levelized Unit Energy Cost (LUEC) calculation, and market benefit comparison methodology. In this paper, economic evaluation of NPP lifetime management was carried out by using these three methodologies, and the results of each was compared with the other methodologies. With these three methodologies, break even points of investment cost related to life extension of nuclear power plant were calculated. It was turned out to be as a analysis result that LUEC is more conservative than present worth calculation and that benefit comparison is more conservative than LUEC, which means that Market Benefit Comparison is the most conservative methodology, and which means base load demand of the future would be far more important than any other factors such as capacity factor, investment cost of life extension, and performance of replacing power plant

User manual for PACTOLUS: a code for computing power costs.

Energy Technology Data Exchange (ETDEWEB)

Huber, H.D.; Bloomster, C.H.

1979-02-01

PACTOLUS is a computer code for calculating the cost of generating electricity. Through appropriate definition of the input data, PACTOLUS can calculate the cost of generating electricity from a wide variety of power plants, including nuclear, fossil, geothermal, solar, and other types of advanced energy systems. The purpose of PACTOLUS is to develop cash flows and calculate the unit busbar power cost (mills/kWh) over the entire life of a power plant. The cash flow information is calculated by two principal models: the Fuel Model and the Discounted Cash Flow Model. The Fuel Model is an engineering cost model which calculates the cash flow for the fuel cycle costs over the project lifetime based on input data defining the fuel material requirements, the unit costs of fuel materials and processes, the process lead and lag times, and the schedule of the capacity factor for the plant. For nuclear plants, the Fuel Model calculates the cash flow for the entire nuclear fuel cycle. For fossil plants, the Fuel Model calculates the cash flow for the fossil fuel purchases. The Discounted Cash Flow Model combines the fuel costs generated by the Fuel Model with input data on the capital costs, capital structure, licensing time, construction time, rates of return on capital, tax rates, operating costs, and depreciation method of the plant to calculate the cash flow for the entire lifetime of the project. The financial and tax structure for both investor-owned utilities and municipal utilities can be simulated through varying the rates of return on equity and debt, the debt-equity ratios, and tax rates. The Discounted Cash Flow Model uses the principal that the present worth of the revenues will be equal to the present worth of the expenses including the return on investment over the economic life of the project. This manual explains how to prepare the input data, execute cases, and interpret the output results. (RWR)

User manual for PACTOLUS: a code for computing power costs

International Nuclear Information System (INIS)

Huber, H.D.; Bloomster, C.H.

1979-02-01

PACTOLUS is a computer code for calculating the cost of generating electricity. Through appropriate definition of the input data, PACTOLUS can calculate the cost of generating electricity from a wide variety of power plants, including nuclear, fossil, geothermal, solar, and other types of advanced energy systems. The purpose of PACTOLUS is to develop cash flows and calculate the unit busbar power cost (mills/kWh) over the entire life of a power plant. The cash flow information is calculated by two principal models: the Fuel Model and the Discounted Cash Flow Model. The Fuel Model is an engineering cost model which calculates the cash flow for the fuel cycle costs over the project lifetime based on input data defining the fuel material requirements, the unit costs of fuel materials and processes, the process lead and lag times, and the schedule of the capacity factor for the plant. For nuclear plants, the Fuel Model calculates the cash flow for the entire nuclear fuel cycle. For fossil plants, the Fuel Model calculates the cash flow for the fossil fuel purchases. The Discounted Cash Flow Model combines the fuel costs generated by the Fuel Model with input data on the capital costs, capital structure, licensing time, construction time, rates of return on capital, tax rates, operating costs, and depreciation method of the plant to calculate the cash flow for the entire lifetime of the project. The financial and tax structure for both investor-owned utilities and municipal utilities can be simulated through varying the rates of return on equity and debt, the debt-equity ratios, and tax rates. The Discounted Cash Flow Model uses the principal that the present worth of the revenues will be equal to the present worth of the expenses including the return on investment over the economic life of the project. This manual explains how to prepare the input data, execute cases, and interpret the output results with the updated version of PACTOLUS. 11 figures, 2 tables

Study of creep-fatigue behavior in a 1000 MW rotor using a phenomenological lifetime model

Energy Technology Data Exchange (ETDEWEB)

Zhao, Nailong; Wang, Weizhe; Jiang, Jishen; Liu, Yingzheng [School of Mechanical Engineering, Shanghai (China)

2017-02-15

In this study, the phenomenological lifetime model was applied to part of an ultra-supercritical steam turbine rotor model to predict its lifetime as a post processing of the finite element method. To validate the accuracy and adaptation of the post processing program, stress strain hysteresis loops of a cylinderal model under service-like load cycle conditions in cycle N = 1 and 300 were constructed, and the comparison of the results with experimental data on the same cylinderal specimen showed them to be satisfactory. The temperature and von Mises stress distributions of the rotor during a startup-running-shutdown-natural cool process were numerically studied using ABAQUS and the damage caused by the interaction of creep and fatigue was subsequently computed and discussed. It was found that the maximum damage appeared at the inlet notch zone, with the blade groove areas and the front notch areas also suffering a large damage amplitude.

Expectation Maximization Algorithm for Box-Cox Transformation Cure Rate Model and Assessment of Model Misspecification Under Weibull Lifetimes.

Science.gov (United States)

Pal, Suvra; Balakrishnan, Narayanaswamy

2018-05-01

In this paper, we develop likelihood inference based on the expectation maximization algorithm for the Box-Cox transformation cure rate model assuming the lifetimes to follow a Weibull distribution. A simulation study is carried out to demonstrate the performance of the proposed estimation method. Through Monte Carlo simulations, we also study the effect of model misspecification on the estimate of cure rate. Finally, we analyze a well-known data on melanoma with the model and the inferential method developed here.

Lifetime income inequality with taxation and public benefits

OpenAIRE

Kemptner, Daniel; Haan, Peter; Prowse, Victoria

2016-01-01

In this paper, we show how taxation, unemployment insurance, welfare, disability benefits and public pensions affect the inequality of lifetime income. Using results from a dynamic life-cycle model estimated using German panel data, we show that taxation and public benefits combined reduce the inequality of lifetime income, measured by the Gini coefficient, by 22\\%. Pensions only slightly reduce inequality in lifetime income. Welfare benefits, meanwhile, make persistent transfers to individua...

Evaluation of a Stratified National Breast Screening Program in the United Kingdom: An Early Model-Based Cost-Effectiveness Analysis.

Science.gov (United States)

Gray, Ewan; Donten, Anna; Karssemeijer, Nico; van Gils, Carla; Evans, D Gareth; Astley, Sue; Payne, Katherine

2017-09-01

To identify the incremental costs and consequences of stratified national breast screening programs (stratified NBSPs) and drivers of relative cost-effectiveness. A decision-analytic model (discrete event simulation) was conceptualized to represent four stratified NBSPs (risk 1, risk 2, masking [supplemental screening for women with higher breast density], and masking and risk 1) compared with the current UK NBSP and no screening. The model assumed a lifetime horizon, the health service perspective to identify costs (£, 2015), and measured consequences in quality-adjusted life-years (QALYs). Multiple data sources were used: systematic reviews of effectiveness and utility, published studies reporting costs, and cohort studies embedded in existing NBSPs. Model parameter uncertainty was assessed using probabilistic sensitivity analysis and one-way sensitivity analysis. The base-case analysis, supported by probabilistic sensitivity analysis, suggested that the risk stratified NBSPs (risk 1 and risk-2) were relatively cost-effective when compared with the current UK NBSP, with incremental cost-effectiveness ratios of £16,689 per QALY and £23,924 per QALY, respectively. Stratified NBSP including masking approaches (supplemental screening for women with higher breast density) was not a cost-effective alternative, with incremental cost-effectiveness ratios of £212,947 per QALY (masking) and £75,254 per QALY (risk 1 and masking). When compared with no screening, all stratified NBSPs could be considered cost-effective. Key drivers of cost-effectiveness were discount rate, natural history model parameters, mammographic sensitivity, and biopsy rates for recalled cases. A key assumption was that the risk model used in the stratification process was perfectly calibrated to the population. This early model-based cost-effectiveness analysis provides indicative evidence for decision makers to understand the key drivers of costs and QALYs for exemplar stratified NBSP. Copyright

SUNSPOT AND STARSPOT LIFETIMES IN A TURBULENT EROSION MODEL

Energy Technology Data Exchange (ETDEWEB)

Litvinenko, Yuri E. [Department of Mathematics, University of Waikato, P. B. 3105, Hamilton (New Zealand); Wheatland, M. S. [Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006 (Australia)

2017-01-10

Quantitative models of sunspot and starspot decay predict the timescale of magnetic diffusion and may yield important constraints in stellar dynamo models. Motivated by recent measurements of starspot lifetimes, we investigate the disintegration of a magnetic flux tube by nonlinear diffusion. Previous theoretical studies are extended by considering two physically motivated functional forms for the nonlinear diffusion coefficient D : an inverse power-law dependence D ∝ B {sup −ν} and a step-function dependence of D on the magnetic field magnitude B . Analytical self-similar solutions are presented for the power-law case, including solutions exhibiting “super fast” diffusion. For the step-function case, the heat-balance integral method yields approximate solutions, valid for moderately suppressed diffusion in the spot. The accuracy of the resulting solutions is confirmed numerically, using a method which provides an accurate description of long-time evolution by imposing boundary conditions at infinite distance from the spot. The new models may allow insight into the differences and similarities between sunspots and starspots.

Parametric cost models for space telescopes

Science.gov (United States)

Stahl, H. Philip; Henrichs, Todd; Dollinger, Courtnay

2017-11-01

Multivariable parametric cost models for space telescopes provide several benefits to designers and space system project managers. They identify major architectural cost drivers and allow high-level design trades. They enable cost-benefit analysis for technology development investment. And, they provide a basis for estimating total project cost. A survey of historical models found that there is no definitive space telescope cost model. In fact, published models vary greatly [1]. Thus, there is a need for parametric space telescopes cost models. An effort is underway to develop single variable [2] and multi-variable [3] parametric space telescope cost models based on the latest available data and applying rigorous analytical techniques. Specific cost estimating relationships (CERs) have been developed which show that aperture diameter is the primary cost driver for large space telescopes; technology development as a function of time reduces cost at the rate of 50% per 17 years; it costs less per square meter of collecting aperture to build a large telescope than a small telescope; and increasing mass reduces cost.

Parametric Cost Models for Space Telescopes

Science.gov (United States)

Stahl, H. Philip; Henrichs, Todd; Dollinger, Courtney

2010-01-01

Multivariable parametric cost models for space telescopes provide several benefits to designers and space system project managers. They identify major architectural cost drivers and allow high-level design trades. They enable cost-benefit analysis for technology development investment. And, they provide a basis for estimating total project cost. A survey of historical models found that there is no definitive space telescope cost model. In fact, published models vary greatly [1]. Thus, there is a need for parametric space telescopes cost models. An effort is underway to develop single variable [2] and multi-variable [3] parametric space telescope cost models based on the latest available data and applying rigorous analytical techniques. Specific cost estimating relationships (CERs) have been developed which show that aperture diameter is the primary cost driver for large space telescopes; technology development as a function of time reduces cost at the rate of 50% per 17 years; it costs less per square meter of collecting aperture to build a large telescope than a small telescope; and increasing mass reduces cost.

Sexy sons from re-mating do not recoup the direct costs of harmful male interactions in the Drosophila melanogaster laboratory model system.

Science.gov (United States)

Orteiza, N; Linder, J E; Rice, W R

2005-09-01

The empirical foundation for sexual conflict theory is the data from many different taxa demonstrating that females are harmed while interacting with males. However, the interpretation of this keystone evidence has been challenged because females may more than counterbalance the direct costs of interacting with males by the indirect benefits of obtaining higher quality genes for their offspring. A quantification of this trade-off is critical to resolve the controversy and is presented here. A multi-generation fitness assay in the Drosophila melanogaster laboratory model system was used to quantify both the direct costs to females due to interactions with males and indirect benefits via sexy sons. We specifically focus on the interactions that occur between males and nonvirgin females. In the laboratory environment of our base population, females mate soon after eclosion and store sufficient sperm for their entire lifetime, yet males persistently court these nonvirgin females and frequently succeed in re-mating them. Females may benefit from these interactions despite direct costs to their lifetime fecundity if re-mating allows them to trade-up to mates of higher genetic quality and thereby secure indirect benefits for their offspring. We found that direct costs of interactions between males and nonvirgin females substantially exceeded indirect benefits through sexy sons. These data, in combination with past studies of the good genes route of indirect benefits, demonstrate that inter-sexual interactions drive sexually antagonistic co-evolution in this model system.

Cost-effectiveness of cervical-cancer screening in five developing countries.

Science.gov (United States)

Goldie, Sue J; Gaffikin, Lynne; Goldhaber-Fiebert, Jeremy D; Gordillo-Tobar, Amparo; Levin, Carol; Mahé, Cédric; Wright, Thomas C

2005-11-17

Cervical-cancer screening strategies that involve the use of conventional cytology and require multiple visits have been impractical in developing countries. We used computer-based models to assess the cost-effectiveness of a variety of cervical-cancer screening strategies in India, Kenya, Peru, South Africa, and Thailand. Primary data were combined with data from the literature to estimate age-specific incidence and mortality rates for cancer and the effectiveness of screening for and treatment of precancerous lesions. We assessed the direct medical, time, and program-related costs of strategies that differed according to screening test, targeted age and frequency, and number of clinic visits required. Single-visit strategies involved the assumption that screening and treatment could be provided in the same day. Outcomes included the lifetime risk of cancer, years of life saved, lifetime costs, and cost-effectiveness ratios (cost per year of life saved). The most cost-effective strategies were those that required the fewest visits, resulting in improved follow-up testing and treatment. Screening women once in their lifetime, at the age of 35 years, with a one-visit or two-visit screening strategy involving visual inspection of the cervix with acetic acid or DNA testing for human papillomavirus (HPV) in cervical cell samples, reduced the lifetime risk of cancer by approximately 25 to 36 percent, and cost less than 500 dollars per year of life saved. Relative cancer risk declined by an additional 40 percent with two screenings (at 35 and 40 years of age), resulting in a cost per year of life saved that was less than each country's per capita gross domestic product--a very cost-effective result, according to the Commission on Macroeconomics and Health. Cervical-cancer screening strategies incorporating visual inspection of the cervix with acetic acid or DNA testing for HPV in one or two clinical visits are cost-effective alternatives to conventional three

Preventing pressure ulcers in long-term care: a cost-effectiveness analysis.

Science.gov (United States)

Pham, Ba'; Stern, Anita; Chen, Wendong; Sander, Beate; John-Baptiste, Ava; Thein, Hla-Hla; Gomes, Tara; Wodchis, Walter P; Bayoumi, Ahmed; Machado, Márcio; Carcone, Steven; Krahn, Murray

2011-11-14

Pressure ulcers are common in many care settings, with adverse health outcomes and high treatment costs. We evaluated the cost-effectiveness of evidence-based strategies to improve current prevention practice in long-term care facilities. We used a validated Markov model to compare current prevention practice with the following 4 quality improvement strategies: (1) pressure redistribution mattresses for all residents, (2) oral nutritional supplements for high-risk residents with recent weight loss, (3) skin emollients for high-risk residents with dry skin, and (4) foam cleansing for high-risk residents requiring incontinence care. Primary outcomes included lifetime risk of stage 2 to 4 pressure ulcers, quality-adjusted life-years (QALYs), and lifetime costs, calculated according to a single health care payer's perspective and expressed in 2009 Canadian dollars (Can$1 = US$0.84). Strategies cost on average $11.66 per resident per week. They reduced lifetime risk; the associated number needed to treat was 45 (strategy 1), 63 (strategy 4), 158 (strategy 3), and 333 (strategy 2). Strategy 1 and 4 minimally improved QALYs and reduced the mean lifetime cost by $115 and $179 per resident, respectively. The cost per QALY gained was approximately $78 000 for strategy 3 and $7.8 million for strategy 2. If decision makers are willing to pay up to $50 000 for 1 QALY gained, the probability that improving prevention is cost-effective is 94% (strategy 4), 82% (strategy 1), 43% (strategy 3), and 1% (strategy 2). The clinical and economic evidence supports pressure redistribution mattresses for all long-term care residents. Improving prevention with perineal foam cleansers and dry skin emollients appears to be cost-effective, but firm conclusions are limited by the available clinical evidence.

Cost Model for Digital Curation: Cost of Digital Migration

DEFF Research Database (Denmark)

Kejser, Ulla Bøgvad; Nielsen, Anders Bo; Thirifays, Alex

2009-01-01

The Danish Ministry of Culture is currently funding a project to set up a model for costing preservation of digital materials held by national cultural heritage institutions. The overall objective of the project is to provide a basis for comparing and estimating future financial requirements...... for digital preservation and to increase cost effectiveness of digital preservation activities. In this study we describe an activity based costing methodology for digital preservation based on the OAIS Reference Model. In order to estimate the cost of digital migrations we have identified cost critical...

Lifetime measurements

International Nuclear Information System (INIS)

Fossan, D.B.; Warburton, E.K.

1974-01-01

Lifetime measurements are discussed, concentrating on the electronic technique, the recoil distance method (RDM), and the Doppler shift attenuation method (DSAM). A brief review of several indirect timing techniques is given, and their specific advantages and applicability are considered. The relationship between lifetimes of nuclear states and the nuclear structure information obtained from them is examined. A short discussion of channeling and microwave methods of lifetime measurement is presented. (23 figures, 171 references) (U.S.)

Studies in Software Cost Model Behavior: Do We Really Understand Cost Model Performance?

Science.gov (United States)

Lum, Karen; Hihn, Jairus; Menzies, Tim

2006-01-01

While there exists extensive literature on software cost estimation techniques, industry practice continues to rely upon standard regression-based algorithms. These software effort models are typically calibrated or tuned to local conditions using local data. This paper cautions that current approaches to model calibration often produce sub-optimal models because of the large variance problem inherent in cost data and by including far more effort multipliers than the data supports. Building optimal models requires that a wider range of models be considered while correctly calibrating these models requires rejection rules that prune variables and records and use multiple criteria for evaluating model performance. The main contribution of this paper is to document a standard method that integrates formal model identification, estimation, and validation. It also documents what we call the large variance problem that is a leading cause of cost model brittleness or instability.

Using sparse polynomial chaos expansions for the global sensitivity analysis of groundwater lifetime expectancy in a multi-layered hydrogeological model

International Nuclear Information System (INIS)

Deman, G.; Konakli, K.; Sudret, B.; Kerrou, J.; Perrochet, P.; Benabderrahmane, H.

2016-01-01

The study makes use of polynomial chaos expansions to compute Sobol' indices within the frame of a global sensitivity analysis of hydro-dispersive parameters in a simplified vertical cross-section of a segment of the subsurface of the Paris Basin. Applying conservative ranges, the uncertainty in 78 input variables is propagated upon the mean lifetime expectancy of water molecules departing from a specific location within a highly confining layer situated in the middle of the model domain. Lifetime expectancy is a hydrogeological performance measure pertinent to safety analysis with respect to subsurface contaminants, such as radionuclides. The sensitivity analysis indicates that the variability in the mean lifetime expectancy can be sufficiently explained by the uncertainty in the petrofacies, i.e. the sets of porosity and hydraulic conductivity, of only a few layers of the model. The obtained results provide guidance regarding the uncertainty modeling in future investigations employing detailed numerical models of the subsurface of the Paris Basin. Moreover, the study demonstrates the high efficiency of sparse polynomial chaos expansions in computing Sobol' indices for high-dimensional models. - Highlights: • Global sensitivity analysis of a 2D 15-layer groundwater flow model is conducted. • A high-dimensional random input comprising 78 parameters is considered. • The variability in the mean lifetime expectancy for the central layer is examined. • Sparse polynomial chaos expansions are used to compute Sobol' sensitivity indices. • The petrofacies of a few layers can sufficiently explain the response variance.

Opportunity cost for early treatment of Chagas disease in Mexico.

Directory of Open Access Journals (Sweden)

Janine M Ramsey

2014-04-01

Full Text Available BACKGROUND: Given current neglect for Chagas disease in public health programs in Mexico, future healthcare and economic development policies will need a more robust model to analyze costs and impacts of timely clinical attention of infected populations. METHODOLOGY/PRINCIPAL FINDINGS: A Markov decision model was constructed to simulate the natural history of a Chagas disease cohort in Mexico and to project the associated short and long-term clinical outcomes and corresponding costs. The lifetime cost for a timely diagnosed and treated Chagas disease patient is US$ 10,160, while the cost for an undiagnosed individual is US$ 11,877. The cost of a diagnosed and treated case increases 24-fold from early acute to indeterminate stage. The major cost component for lifetime cost was working days lost, between 44% and 75%, depending on the program scenario for timely diagnosis and treatment. CONCLUSIONS/SIGNIFICANCE: In the long term, it is cheaper to diagnose and treat chagasic patients early, instead of doing nothing. This finding by itself argues for the need to shift current policy, in order to prioritize and attend this neglected disease for the benefit of social and economic development, which implies including treatment drugs in the national formularies. Present results are even more relevant, if one considers that timely diagnosis and treatment can arrest clinical progression and enhance a chronic patient's quality of life.

Opportunity cost for early treatment of Chagas disease in Mexico.

Science.gov (United States)

Ramsey, Janine M; Elizondo-Cano, Miguel; Sanchez-González, Gilberto; Peña-Nieves, Adriana; Figueroa-Lara, Alejandro

2014-04-01

Given current neglect for Chagas disease in public health programs in Mexico, future healthcare and economic development policies will need a more robust model to analyze costs and impacts of timely clinical attention of infected populations. A Markov decision model was constructed to simulate the natural history of a Chagas disease cohort in Mexico and to project the associated short and long-term clinical outcomes and corresponding costs. The lifetime cost for a timely diagnosed and treated Chagas disease patient is US$ 10,160, while the cost for an undiagnosed individual is US$ 11,877. The cost of a diagnosed and treated case increases 24-fold from early acute to indeterminate stage. The major cost component for lifetime cost was working days lost, between 44% and 75%, depending on the program scenario for timely diagnosis and treatment. In the long term, it is cheaper to diagnose and treat chagasic patients early, instead of doing nothing. This finding by itself argues for the need to shift current policy, in order to prioritize and attend this neglected disease for the benefit of social and economic development, which implies including treatment drugs in the national formularies. Present results are even more relevant, if one considers that timely diagnosis and treatment can arrest clinical progression and enhance a chronic patient's quality of life.

Prolonging fuel cell stack lifetime based on Pontryagin's Minimum Principle in fuel cell hybrid vehicles and its economic influence evaluation

Science.gov (United States)

Zheng, C. H.; Xu, G. Q.; Park, Y. I.; Lim, W. S.; Cha, S. W.

2014-02-01

The lifetime of fuel cell stacks is a major issue currently, especially for automotive applications. In order to take into account the lifetime of fuel cell stacks while considering the fuel consumption minimization in fuel cell hybrid vehicles (FCHVs), a Pontryagin's Minimum Principle (PMP)-based power management strategy is proposed in this research. This strategy has the effect of prolonging the lifetime of fuel cell stacks. However, there is a tradeoff between the fuel cell stack lifetime and the fuel consumption when this strategy is applied to an FCHV. Verifying the positive economic influence of this strategy is necessary in order to demonstrate its superiority. In this research, the economic influence of the proposed strategy is assessed according to an evaluating cost which is dependent on the fuel cell stack cost, the hydrogen cost, the fuel cell stack lifetime, and the lifetime prolonging impact on the fuel cell stack. Simulation results derived from the proposed power management strategy are also used to evaluate the economic influence. As a result, the positive economic influence of the proposed PMP-based power management strategy is proved for both current and future FCHVs.

Modeling the Cost Effectiveness of Neuroimaging-Based Treatment of Acute Wake-Up Stroke.

Directory of Open Access Journals (Sweden)

Ankur Pandya

Full Text Available Thrombolytic treatment (tissue-type plasminogen activator [tPA] is only recommended for acute ischemic stroke patients with stroke onset time 4.5 hours, 46.3% experienced a good stroke outcome. Lifetime discounted QALYs and costs were 5.312 and $88,247 for the no treatment strategy and 5.342 and $90,869 for the MRI-based strategy, resulting in an ICER of $88,000/QALY. Results were sensitive to variations in patient- and provider-specific factors such as sleep duration, hospital travel and door-to-needle times, as well as onset probability distribution, MRI specificity, and mRS utility values.Our model-based findings suggest that an MRI-based treatment strategy for this population could be cost-effective and quantifies the impact that patient- and provider-specific factors, such as sleep duration, hospital travel and door-to-needle times, could have on the optimal decision for wake-up stroke patients.

Cost Modeling for Space Telescope

Science.gov (United States)

Stahl, H. Philip

2011-01-01

Parametric cost models are an important tool for planning missions, compare concepts and justify technology investments. This paper presents on-going efforts to develop single variable and multi-variable cost models for space telescope optical telescope assembly (OTA). These models are based on data collected from historical space telescope missions. Standard statistical methods are used to derive CERs for OTA cost versus aperture diameter and mass. The results are compared with previously published models.

The Lifetime Economic Burden of Inaccurate HER2 Testing: Estimating the Costs of False-Positive and False-Negative HER2 Test Results in US Patients with Early-Stage Breast Cancer.

Science.gov (United States)

Garrison, Louis P; Babigumira, Joseph B; Masaquel, Anthony; Wang, Bruce C M; Lalla, Deepa; Brammer, Melissa

2015-06-01

Patients with breast cancer whose tumors test positive for human epidermal growth factor receptor 2 (HER2) are treated with HER2-targeted therapies such as trastuzumab, but limitations with HER2 testing may lead to false-positive (FP) or false-negative (FN) results. To develop a US-level model to estimate the effect of tumor misclassification on health care costs and patient quality-adjusted life-years (QALYs). Decision analysis was used to estimate the number of patients with early-stage breast cancer (EBC) whose HER2 status was misclassified in 2012. FP results were assumed to generate unnecessary trastuzumab costs and unnecessary cases of trastuzumab-related cardiotoxicity. FN results were assumed to save money on trastuzumab, but with a loss of QALYs and greater risk of disease recurrence and its associated costs. QALYs were valued at $100,000 under a net monetary benefit approach. Among 226,870 women diagnosed with EBC in 2012, 3.12% (n = 7,070) and 2.18% (n = 4,955) were estimated to have had FP and FN test results, respectively. Approximately 8400 QALYs (discounted, lifetime) were lost among women not receiving trastuzumab because of FN results. The estimated incremental per-patient lifetime burden of FP or FN results was $58,900 and $116,000, respectively. The implied incremental losses to society were $417 million and $575 million, respectively. HER2 tests result in misclassification and nonoptimal treatment of approximately 12,025 US patients with EBC annually. The total economic societal loss of nearly $1 billion suggests that improvements in HER2 testing accuracy are needed and that further clinical and economic studies are warranted. Copyright © 2015 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

A global economic model to assess the cost-effectiveness of new treatments for advanced breast cancer in Canada.

Science.gov (United States)

Beauchemin, C; Letarte, N; Mathurin, K; Yelle, L; Lachaine, J

2016-06-01

Objective Considering the increasing number of treatment options for metastatic breast cancer (MBC), it is important to develop high-quality methods to assess the cost-effectiveness of new anti-cancer drugs. This study aims to develop a global economic model that could be used as a benchmark for the economic evaluation of new therapies for MBC. Methods The Global Pharmacoeconomics of Metastatic Breast Cancer (GPMBC) model is a Markov model that was constructed to estimate the incremental cost per quality-adjusted life years (QALY) of new treatments for MBC from a Canadian healthcare system perspective over a lifetime horizon. Specific parameters included in the model are cost of drug treatment, survival outcomes, and incidence of treatment-related adverse events (AEs). Global parameters are patient characteristics, health states utilities, disutilities, and costs associated with treatment-related AEs, as well as costs associated with drug administration, medical follow-up, and end-of-life care. The GPMBC model was tested and validated in a specific context, by assessing the cost-effectiveness of lapatinib plus letrozole compared with other widely used first-line therapies for post-menopausal women with hormone receptor-positive (HR+) and epidermal growth factor receptor 2-positive (HER2+) MBC. Results When tested, the GPMBC model led to incremental cost-utility ratios of CA$131 811 per QALY, CA$56 211 per QALY, and CA$102 477 per QALY for the comparison of lapatinib plus letrozole vs letrozole alone, trastuzumab plus anastrozole, and anastrozole alone, respectively. Results of the model testing were quite similar to those obtained by Delea et al., who also assessed the cost-effectiveness of lapatinib in combination with letrozole in HR+/HER2 + MBC in Canada, thus suggesting that the GPMBC model can replicate results of well-conducted economic evaluations. Conclusions The GPMBC model can be very valuable as it allows a quick and valid assessment of the cost

Maintenance cost models in deregulated power systems under opportunity costs

International Nuclear Information System (INIS)

Al-Arfaj, K.; Dahal, K.; Azaiez, M.N.

2007-01-01

In a centralized power system, the operator is responsible for scheduling maintenance. There are different types of maintenance, including corrective maintenance; predictive maintenance; preventive maintenance; and reliability-centred maintenance. The main cause of power failures is poor maintenance. As such, maintenance costs play a significant role in deregulated power systems. They include direct costs associated with material and labor costs as well as indirect costs associated with spare parts inventory, shipment, test equipment, indirect labor, opportunity costs and cost of failure. In maintenance scheduling and planning, the cost function is the only component of the objective function. This paper presented the results of a study in which different components of maintenance costs were modeled. The maintenance models were formulated as an optimization problem with single and multiple objectives and a set of constraints. The maintenance costs models could be used to schedule the maintenance activities of power generators more accurately and to identify the best maintenance strategies over a period of time as they consider failure and opportunity costs in a deregulated environment. 32 refs., 4 tabs., 4 figs

Coupled modeling of the competitive gettering of transition metals and impact on performance of lifetime sensitive devices

Science.gov (United States)

Yazdani, Armin; Chen, Renyu; Dunham, Scott T.

2017-03-01

This work models competitive gettering of metals (Cu, Ni, Fe, Mo, and W) by boron, phosphorus, and dislocation loops, and connects those results directly to device performance. Density functional theory calculations were first performed to determine the binding energies of metals to the gettering sites, and based on that, continuum models were developed to model the redistribution and trapping of the metals. Our models found that Fe is most strongly trapped by the dislocation loops while Cu and Ni are most strongly trapped by the P4V clusters formed in high phosphorus concentrations. In addition, it is found that none of the mentioned gettering sites are effective in gettering Mo and W. The calculated metal redistribution along with the associated capture cross sections and trap energy levels are passed to device simulation via the recombination models to calculate carrier lifetime and the resulting device performance. Thereby, a comprehensive and predictive TCAD framework is developed to optimize the processing conditions to maximize performance of lifetime sensitive devices.

Resolving Nuclear Reactor Lifetime Extension Questions: A Combined Multiscale Modeling and Positron Characterization approach

International Nuclear Information System (INIS)

Wirth, B; Asoka-Kumar, P; Denison, A; Glade, S; Howell, R; Marian, J; Odette, G; Sterne, P

2004-01-01

The objective of this work is to determine the chemical composition of nanometer precipitates responsible for irradiation hardening and embrittlement of reactor pressure vessel steels, which threaten to limit the operating lifetime of nuclear power plants worldwide. The scientific approach incorporates computational multiscale modeling of radiation damage and microstructural evolution in Fe-Cu-Ni-Mn alloys, and experimental characterization by positron annihilation spectroscopy and small angle neutron scattering. The modeling and experimental results are

Estimation of the Service Lifetime of Concrete Bridges

DEFF Research Database (Denmark)

Thoft-Christensen, Palle

In this paper estimation of the service lifetime of concrete bridges is discussed. The main reason for deterioration of concrete bridges is corrosion of the reinforcement. Therefore, modelling of the corrosion process is an important aspect of the estimation of the service lifetime. In this paper...

Proposed Reliability/Cost Model

Science.gov (United States)

Delionback, L. M.

1982-01-01

New technique estimates cost of improvement in reliability for complex system. Model format/approach is dependent upon use of subsystem cost-estimating relationships (CER's) in devising cost-effective policy. Proposed methodology should have application in broad range of engineering management decisions.

Endogenous fertility and development traps with endogenous lifetime

OpenAIRE

Fanti, Luciano; Gori, Luca

2010-01-01

We extend the literature on endogenous lifetime and economic growth by Chakraborty (2004) and Bunzel and Qiao (2005) to endogenous fertility. We show that development traps due to underinvestments in health cannot appear when fertility is an economic decision variable and the costs of children are represented by a constant fraction of the parents' income used for their upbringing.

Influence of plug-in hybrid electric vehicle charging strategies on charging and battery degradation costs

International Nuclear Information System (INIS)

Lunz, Benedikt; Yan, Zexiong; Gerschler, Jochen Bernhard; Sauer, Dirk Uwe

2012-01-01

The profitability of plug-in hybrid electric vehicles (PHEVs) is significantly influenced by battery aging and electricity costs. Therefore a simulation model for PHEVs in the distribution grid is presented which allows to compare the influence of different charging strategies on these costs. The simulation is based on real-world driving behavior and European Energy Exchange (EEX) intraday prices for obtaining representative results. The analysis of comprehensive lithium-ion battery aging tests performed within this study shows that especially high battery states of charge (SOCs) decrease battery lifetime, whereas the cycling of batteries at medium SOCs only has a minor contribution to aging. Charging strategies that take into account the previously mentioned effects are introduced, and the SOC distributions and cycle loads of the vehicle battery are investigated. It can be shown that appropriate charging strategies significantly increase battery lifetime and reduce charging costs at the same time. Possible savings due to lifetime extension of the vehicle battery are approximately two times higher than revenues due to energy trading. The findings of this work indicate that car manufacturers and energy/mobility providers have to make efforts for developing intelligent charging strategies to reduce mobility costs and thus foster the introduction of electric mobility. - Highlights: ► Modeling of PHEVs based on real-world driving behavior and electricity prices. ► Consideration of battery degradation for the calculation of mobility costs. ► Smart charging decreases battery degradation and electricity costs simultaneously. ► Reduction of battery degradation costs is around two times higher than reduction of electricity costs.

Statistical Methods for Detecting and Modeling General Patterns and Relationships in Lifetime Data

Energy Technology Data Exchange (ETDEWEB)

Kvaloey, Jan Terje

1999-04-01

In this thesis, the author tries to develop methods of detecting and modeling general patterns and relationships in lifetime data. Tests with power against nonmonotonic trends and nonmonotonic co variate effects are considered, and nonparametric regression methods which allow estimation of fairly general nonlinear relationships are studied. Practical uses of some of the methods are illustrated although in a medical rather than engineering or technological context.

Accelerated lifetime test of vibration isolator made of Metal Rubber material

Science.gov (United States)

Ao, Hongrui; Ma, Yong; Wang, Xianbiao; Chen, Jianye; Jiang, Hongyuan

2017-01-01

The Metal Rubber material (MR) is a kind of material with nonlinear damping characteristics for its application in the field of aerospace, petrochemical industry and so on. The study on the lifetime of MR material is impendent to its application in engineering. Based on the dynamic characteristic of MR, the accelerated lifetime experiments of vibration isolators made of MR working under random vibration load were conducted. The effects of structural parameters of MR components on the lifetime of isolators were studied and modelled with the fitting curves of degradation data. The lifetime prediction methods were proposed based on the models.

The neutron lifetime experiment PENeLOPE

Energy Technology Data Exchange (ETDEWEB)

Schreyer, Wolfgang [Technische Universitaet Muenchen (Germany); Collaboration: PENeLOPE-Collaboration

2015-07-01

The neutron lifetime τ{sub n}=880.3±1.1 s is an important parameter in the Standard Model of particle physics and in Big Bang cosmology. Several systematic corrections of previously published results reduced the PDG world average by several σ in the last years and call for a new experiment with complementary systematics. The experiment PENeLOPE, currently under construction at the Physik-Department of Technische Universitaet Muenchen, aims to determine the neutron lifetime with a precision of 0.1 s. It will trap ultra-cold neutrons in a magneto-gravitational trap using a large superconducting magnet and will measure their lifetime by both neutron counting and online proton detection. This presentation gives an overview over the latest developments of the experiment.

Model of lifetime prediction - Study of the behaviour of polymers and organic matrix composites

International Nuclear Information System (INIS)

Colin, X.

2009-01-01

The team 'Aging of Organic Materials' of the Process and Engineering Laboratory in Mechanics and Materials (Arts et Metiers, ParisTech) has developed the model of lifetime prediction for the prediction of the behaviour of polymers and organic composites. This model has already given evidence of a real predictive mean for various industrial applications, as for instance the prediction of a rupture under the coupled effect of a mechanical load and a chemical degradation. (O.M.)

Implementing a trustworthy cost-accounting model.

Science.gov (United States)

Spence, Jay; Seargeant, Dan

2015-03-01

Hospitals and health systems can develop an effective cost-accounting model and maximize the effectiveness of their cost-accounting teams by focusing on six key areas: Implementing an enhanced data model. Reconciling data efficiently. Accommodating multiple cost-modeling techniques. Improving transparency of cost allocations. Securing department manager participation. Providing essential education and training to staff members and stakeholders.

Atmospheric Muon Lifetime, Standard Model of Particles and the Lead Stopping Power for Muons

Science.gov (United States)

Gutarra-Leon, Angel; Barazandeh, Cioli; Majewski, Walerian

2017-01-01

The muon is a fundamental particles of matter. It decays into three other leptons through an exchange of the weak vector bosons W +/W-. Muons are present in the atmosphere from cosmic ray showers. By detecting the time delay between arrival of the muon and an appearance of the decay electron in our detector, we'll measure muon's lifetime at rest. From the lifetime we should be able to find the ratio gw /MW of the weak coupling constant gw (a weak analog of the electric charge) to the mass of the W-boson MW. Vacuum expectation value v of the Higg's field, which determines the masses of all particles of the Standard Model (SM), could be then calculated from our muon experiment as v =2MWc2/gw =(τ m μc2/6 π3ĥ)1/4m μc2 in terms of muon mass mµand muon lifetime τ only. Using known experimental value for MWc2 = 80.4 GeV we'll find the weak coupling constant gw. Using the SM relation e =gwsin θ√ hc ɛ0 with the experimental value of the Z0-photon weak mixing angle θ = 29o we could find from our muon lifetime the value of the elementary electric charge e. We'll determine the sea-level fluxes of low-energy and high-energy cosmic muons, then we'll shield the detector with varying thicknesses of lead plates and find the energy-dependent muon stopping power in lead.

Spectrum Fatigue Lifetime and Residual Strength for Fiberglass Laminates; TOPICAL

International Nuclear Information System (INIS)

WAHL, NEIL K.; MANDELL, JOHN F.; SAMBORSKY, DANIEL D.

2002-01-01

This report addresses the effects of spectrum loading on lifetime and residual strength of a typical fiberglass laminate configuration used in wind turbine blade construction. Over 1100 tests have been run on laboratory specimens under a variety of load sequences. Repeated block loading at two or more load levels, either tensile-tensile, compressive-compressive, or reversing, as well as more random standard spectra have been studied. Data have been obtained for residual strength at various stages of the lifetime. Several lifetime prediction theories have been applied to the results. The repeated block loading data show lifetimes that are usually shorter than predicted by the most widely used linear damage accumulation theory, Miner's sum. Actual lifetimes are in the range of 10 to 20 percent of predicted lifetime in many cases. Linear and nonlinear residual strength models tend to fit the data better than Miner's sum, with the nonlinear providing a better fit of the two. Direct tests of residual strength at various fractions of the lifetime are consistent with the residual strength models. Load sequencing effects are found to be insignificant. The more a spectrum deviates from constant amplitude, the more sensitive predictions are to the damage law used. The nonlinear model provided improved correlation with test data for a modified standard wind turbine spectrum. When a single, relatively high load cycle was removed, all models provided similar, though somewhat non-conservative correlation with the experimental results. Predictions for the full spectrum, including tensile and compressive loads were slightly non-conservative relative to the experimental data, and accurately captured the trend with varying maximum load. The nonlinear residual strength based prediction with a power law S-N curve extrapolation provided the best fit to the data in most cases. The selection of the constant amplitude fatigue regression model becomes important at the lower stress, higher

Attrition Cost Model Instruction Manual

Science.gov (United States)

Yanagiura, Takeshi

2012-01-01

This instruction manual explains in detail how to use the Attrition Cost Model program, which estimates the cost of student attrition for a state's higher education system. Programmed with SAS, this model allows users to instantly calculate the cost of attrition and the cumulative attrition rate that is based on the most recent retention and…

APT cost scaling: Preliminary indications from a Parametric Costing Model (PCM)

International Nuclear Information System (INIS)

Krakowski, R.A.

1995-01-01

A Parametric Costing Model has been created and evaluate as a first step in quantitatively understanding important design options for the Accelerator Production of Tritium (APT) concept. This model couples key economic and technical elements of APT in a two-parameter search of beam energy and beam power that minimizes costs within a range of operating constraints. The costing and engineering depth of the Parametric Costing Model is minimal at the present open-quotes entry levelclose quotes, and is intended only to demonstrate a potential for a more-detailed, cost-based integrating design tool. After describing the present basis of the Parametric Costing Model and giving an example of a single parametric scaling run derived therefrom, the impacts of choices related to resistive versus superconducting accelerator structures and cost of electricity versus plant availability (open-quotes load curveclose quotes) are reported. Areas of further development and application are suggested

Optimal Scheduling of Integrated Energy Systems with Combined Heat and Power Generation, Photovoltaic and Energy Storage Considering Battery Lifetime Loss

Directory of Open Access Journals (Sweden)

Yongli Wang

2018-06-01

Full Text Available Integrated energy systems (IESs are considered a trending solution for the energy crisis and environmental problems. However, the diversity of energy sources and the complexity of the IES have brought challenges to the economic operation of IESs. Aiming at achieving optimal scheduling of components, an IES operation optimization model including photovoltaic, combined heat and power generation system (CHP and battery energy storage is developed in this paper. The goal of the optimization model is to minimize the operation cost under the system constraints. For the optimization process, an optimization principle is conducted, which achieves maximized utilization of photovoltaic by adjusting the controllable units such as energy storage and gas turbine, as well as taking into account the battery lifetime loss. In addition, an integrated energy system project is taken as a research case to validate the effectiveness of the model via the improved differential evolution algorithm (IDEA. The comparison between IDEA and a traditional differential evolution algorithm shows that IDEA could find the optimal solution faster, owing to the double variation differential strategy. The simulation results in three different battery states which show that the battery lifetime loss is an inevitable factor in the optimization model, and the optimized operation cost in 2016 drastically decreased compared with actual operation data.

The 40 year deadline for the French nuclear stock. Decision process, strengthening option and costs associated with a possible lifetime extension beyond 40 years of EDF reactors

International Nuclear Information System (INIS)

Marignac, Yves

2014-01-01

This report first proposes an overview of the lifetime extension problematic (PLEX) for nuclear plants in a general context (strategy of lifetime extension, and uncertainty and lack of return on experience), and in the case of France (emergence of a strategy of lifetime extension, economic challenges of an extension, uncertainty on investments required by an extension, risk of imposed implicit decisions). It gives a rather detailed overview of the French nuclear reactor fleet, of the status of EDF-operated reactors (construction stages, main lifetime events, regulatory situation of currently exploited reactors) and of their characteristics (common operation principle, main components, main safety functions, main considered severe accidents). It addresses safety issues related to ageing and to the post-Fukushima re-assessment (problematic, robustness increase, limits and weaknesses of additional safety assessments). It presents the currently performed improvements (safety referential, applicable strengthening requirements like safety re-examinations and requirements introduced after Fukushima, applied strengthening prescriptions drawn from additional safety assessments or from the third decennial inspection, with their limitations and perspectives). It proposes strengthening scenarios along with their challenges (in terms of requirement level, procedure and agenda). Three scenarios are proposed (degraded safety, preserved safety, strengthened safety) and analysed in terms of protection against aggressions, diffuse robustness, prevention and management of reactor accident, prevention and management of pool accidents, ultimate control and assistance means. Scenarios are finally compared in terms of costs

Gated Detection Measurements of Phosphorescence Lifetimes

Directory of Open Access Journals (Sweden)

Yordan Kostov

2004-10-01

Full Text Available A low-cost, gated system for measurements of phosphorescence lifetimes is presented. An extensive description of the system operating principles and metrological characteristics is given. Remarkably, the system operates without optical filtering of the LED excitation source. A description of a practical system is also given and its performance is discussed. Because the device effectively suppresses high-level background fluorescence and scattered light, it is expected to find wide-spread application in bioprocess, environmental and biomedical fields.

Preliminary Cost Model for Space Telescopes

Science.gov (United States)

Stahl, H. Philip; Prince, F. Andrew; Smart, Christian; Stephens, Kyle; Henrichs, Todd

2009-01-01

Parametric cost models are routinely used to plan missions, compare concepts and justify technology investments. However, great care is required. Some space telescope cost models, such as those based only on mass, lack sufficient detail to support such analysis and may lead to inaccurate conclusions. Similarly, using ground based telescope models which include the dome cost will also lead to inaccurate conclusions. This paper reviews current and historical models. Then, based on data from 22 different NASA space telescopes, this paper tests those models and presents preliminary analysis of single and multi-variable space telescope cost models.

Cost Concept Model and Gateway Specification

DEFF Research Database (Denmark)

Kejser, Ulla Bøgvad

2014-01-01

This document introduces a Framework supporting the implementation of a cost concept model against which current and future cost models for curating digital assets can be benchmarked. The value built into this cost concept model leverages the comprehensive engagement by the 4C project with various...... to promote interoperability; • A Nested Model for Digital Curation—that visualises the core concepts, demonstrates how they interact and places them into context visually by linking them to A Cost and Benefit Model for Curation; This Framework provides guidance for data collection and associated calculations...

Contactless Spectral-dependent Charge Carrier Lifetime Measurements in Silicon Photovoltaic Materials

Science.gov (United States)

Roller, John; Hamadani, Behrang; Dagenais, Mario

Charge carrier lifetime measurements in bulk or unfinished photovoltaic (PV) materials allow for a more accurate estimate of power conversion efficiency in completed solar cells. In this work, carrier lifetimes in PV-grade silicon wafers are obtained by way of quasi-steady state photoconductance measurements. These measurements use a contactless RF system coupled with varying narrow spectrum input LEDs, ranging in wavelength from 460 nm to 1030 nm. Spectral dependent lifetime measurements allow for determination of bulk and surface properties of the material, including the intrinsic bulk lifetime and the surface recombination velocity. The effective lifetimes are fit to an analytical physics-based model to determine the desired parameters. Passivated and non-passivated samples are both studied and are shown to have good agreement with the theoretical model.

Cost Model Comparison: A Study of Internally and Commercially Developed Cost Models in Use by NASA

Science.gov (United States)

Gupta, Garima

2011-01-01

NASA makes use of numerous cost models to accurately estimate the cost of various components of a mission - hardware, software, mission/ground operations - during the different stages of a mission's lifecycle. The purpose of this project was to survey these models and determine in which respects they are similar and in which they are different. The initial survey included a study of the cost drivers for each model, the form of each model (linear/exponential/other CER, range/point output, capable of risk/sensitivity analysis), and for what types of missions and for what phases of a mission lifecycle each model is capable of estimating cost. The models taken into consideration consisted of both those that were developed by NASA and those that were commercially developed: GSECT, NAFCOM, SCAT, QuickCost, PRICE, and SEER. Once the initial survey was completed, the next step in the project was to compare the cost models' capabilities in terms of Work Breakdown Structure (WBS) elements. This final comparison was then portrayed in a visual manner with Venn diagrams. All of the materials produced in the process of this study were then posted on the Ground Segment Team (GST) Wiki.

Video distribution system cost model

Science.gov (United States)

Gershkoff, I.; Haspert, J. K.; Morgenstern, B.

1980-01-01

A cost model that can be used to systematically identify the costs of procuring and operating satellite linked communications systems is described. The user defines a network configuration by specifying the location of each participating site, the interconnection requirements, and the transmission paths available for the uplink (studio to satellite), downlink (satellite to audience), and voice talkback (between audience and studio) segments of the network. The model uses this information to calculate the least expensive signal distribution path for each participating site. Cost estimates are broken downy by capital, installation, lease, operations and maintenance. The design of the model permits flexibility in specifying network and cost structure.

Cost Models for MMC Manufacturing Processes

Science.gov (United States)

Elzey, Dana M.; Wadley, Haydn N. G.

1996-01-01

Processes for the manufacture of advanced metal matrix composites are rapidly approaching maturity in the research laboratory and there is growing interest in their transition to industrial production. However, research conducted to date has almost exclusively focused on overcoming the technical barriers to producing high-quality material and little attention has been given to the economical feasibility of these laboratory approaches and process cost issues. A quantitative cost modeling (QCM) approach was developed to address these issues. QCM are cost analysis tools based on predictive process models relating process conditions to the attributes of the final product. An important attribute, of the QCM approach is the ability to predict the sensitivity of material production costs to product quality and to quantitatively explore trade-offs between cost and quality. Applications of the cost models allow more efficient direction of future MMC process technology development and a more accurate assessment of MMC market potential. Cost models were developed for two state-of-the art metal matrix composite (MMC) manufacturing processes: tape casting and plasma spray deposition. Quality and Cost models are presented for both processes and the resulting predicted quality-cost curves are presented and discussed.

Development of the Galaxy Chronic Obstructive Pulmonary Disease (COPD) Model Using Data from ECLIPSE: Internal Validation of a Linked-Equations Cohort Model.

Science.gov (United States)

Briggs, Andrew H; Baker, Timothy; Risebrough, Nancy A; Chambers, Mike; Gonzalez-McQuire, Sebastian; Ismaila, Afisi S; Exuzides, Alex; Colby, Chris; Tabberer, Maggie; Muellerova, Hana; Locantore, Nicholas; Rutten van Mölken, Maureen P M H; Lomas, David A

2017-05-01

The recent joint International Society for Pharmacoeconomics and Outcomes Research / Society for Medical Decision Making Modeling Good Research Practices Task Force emphasized the importance of conceptualizing and validating models. We report a new model of chronic obstructive pulmonary disease (COPD) (part of the Galaxy project) founded on a conceptual model, implemented using a novel linked-equation approach, and internally validated. An expert panel developed a conceptual model including causal relationships between disease attributes, progression, and final outcomes. Risk equations describing these relationships were estimated using data from the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE) study, with costs estimated from the TOwards a Revolution in COPD Health (TORCH) study. Implementation as a linked-equation model enabled direct estimation of health service costs and quality-adjusted life years (QALYs) for COPD patients over their lifetimes. Internal validation compared 3 years of predicted cohort experience with ECLIPSE results. At 3 years, the Galaxy COPD model predictions of annual exacerbation rate and annual decline in forced expiratory volume in 1 second fell within the ECLIPSE data confidence limits, although 3-year overall survival was outside the observed confidence limits. Projections of the risk equations over time permitted extrapolation to patient lifetimes. Averaging the predicted cost/QALY outcomes for the different patients within the ECLIPSE cohort gives an estimated lifetime cost of £25,214 (undiscounted)/£20,318 (discounted) and lifetime QALYs of 6.45 (undiscounted/5.24 [discounted]) per ECLIPSE patient. A new form of model for COPD was conceptualized, implemented, and internally validated, based on a series of linked equations using epidemiological data (ECLIPSE) and cost data (TORCH). This Galaxy model predicts COPD outcomes from treatment effects on disease attributes such as lung function

Refractive index sensing using Fluorescence Lifetime Imaging (FLIM)

International Nuclear Information System (INIS)

Jones, Carolyn; Suhling, Klaus

2006-01-01

The fluorescence lifetime is a function of the refractive index of the fluorophore's environment, for example in the case of the biologically important green fluorescent protein (GFP). In order to address the question whether this effect can be exploited to image the local environment of specific proteins in cell biology, we need to determine the distance over which the fluorophore's lifetime is sensitive to the refractive index. To this end, we employ Fluorescence Lifetime Imaging (FLIM) of fluorescein in NaOH buffer at an interface. This approach allows us to map the fluorescence lifetime as a function of distance from a buffer/air and buffer/oil interface. Preliminary data show that the fluorescence lifetime of fluorescein increases near a buffer/air interface and decreases near a buffer/oil interface. The range over which this fluorescence lifetime change occurs is found to be of the order several μm which is consistent with a theoretical model based on the full width at half maximum of the emission spectrum proposed by Toptygin

Selected Tether Applications Cost Model

Science.gov (United States)

Keeley, Michael G.

1988-01-01

Diverse cost-estimating techniques and data combined into single program. Selected Tether Applications Cost Model (STACOM 1.0) is interactive accounting software tool providing means for combining several independent cost-estimating programs into fully-integrated mathematical model capable of assessing costs, analyzing benefits, providing file-handling utilities, and putting out information in text and graphical forms to screen, printer, or plotter. Program based on Lotus 1-2-3, version 2.0. Developed to provide clear, concise traceability and visibility into methodology and rationale for estimating costs and benefits of operations of Space Station tether deployer system.

Maximizing Lifetime of Wireless Sensor Networks with Mobile Sink Nodes

Directory of Open Access Journals (Sweden)

Yourong Chen

2014-01-01

Full Text Available In order to maximize network lifetime and balance energy consumption when sink nodes can move, maximizing lifetime of wireless sensor networks with mobile sink nodes (MLMS is researched. The movement path selection method of sink nodes is proposed. Modified subtractive clustering method, k-means method, and nearest neighbor interpolation method are used to obtain the movement paths. The lifetime optimization model is established under flow constraint, energy consumption constraint, link transmission constraint, and other constraints. The model is solved from the perspective of static and mobile data gathering of sink nodes. Subgradient method is used to solve the lifetime optimization model when one sink node stays at one anchor location. Geometric method is used to evaluate the amount of gathering data when sink nodes are moving. Finally, all sensor nodes transmit data according to the optimal data transmission scheme. Sink nodes gather the data along the shortest movement paths. Simulation results show that MLMS can prolong network lifetime, balance node energy consumption, and reduce data gathering latency under appropriate parameters. Under certain conditions, it outperforms Ratio_w, TPGF, RCC, and GRND.

Radio Frequency Energy Harvesting for Long Lifetime Wireless Sensor Networks

DEFF Research Database (Denmark)

Han, Bo; Nielsen, Rasmus Hjorth; Prasad, Ramjee

2014-01-01

In wireless sensor networks energy scarcity is a major concern on energy consumption, and by properly designing on the node network architecture or selecting efficient protocols of the networks, the maximum energy can be reduced significantly thereby increasing the network lifetime. However......, in most of the cases, the sensor nodes are either powered by non-replaceable batteries, or there will be a considerable replacement cost. Thus a self-rechargeable sensor node design is necessary: the sensor node should be able to harvest energy from the environment. Among the existing techniques......, harvesting energy from the radio frequency (RF) waves gives the lowest system design. Previous research on RF energy harvesting is based on the model that the radio energy is omnidirectional in the air. In this paper, a directional transmission/receiving model is proposed which can further overcome the path...

Lifetime estimation for the power semiconductors considering mission profiles in wind power converter

OpenAIRE

Ma, Ke; Liserre, Marco; Blaabjerg, Frede

2013-01-01

As a key component in the wind turbine system, power electronic converter and its power semiconductors suffer from adverse power loadings related to environment, and are proven to have certain failure rates. Therefore, correct lifetime estimation of wind power converter is crucial for the reliability improvement and also for cost reduction of wind power technology. Unfortunately, the existing lifetime estimation methods for the power electronic converter are not yet suitable in the wind power...

Superconducting quasiparticle lifetimes due to spin-fluctuation scattering

International Nuclear Information System (INIS)

Quinlan, S.M.; Scalapino, D.J.; Bulut, N.

1994-01-01

Superconducting quasiparticle lifetimes associated with spin-fluctuation scattering are calculated. A Berk-Schrieffer interaction with an irreducible susceptibility given by a BCS form is used to model the quasiparticle damping due to spin fluctuations. Results are presented for both s-wave and d-wave gaps. Also, quasiparticle lifetimes due to impurity scattering are calculated for a d-wave superconductor

A cost-effectiveness analysis of hormone replacement therapy in the menopause.

Science.gov (United States)

Cheung, A P; Wren, B G

1992-03-02

To evaluate the cost-effectiveness of hormone replacement therapy in the menopause with particular reference to osteoporotic fracture and myocardial infarction. The multiple-decrement form of the life table was the mathematical model used to follow women of age 50 through their lifetime under the "no hormone replacement" and "hormone replacement" assumptions. Standard demographic and health economic techniques were used to calculate the corresponding lifetime differences in direct health care costs (net costs in dollars) and health effects ("net effectiveness" in terms of life expectancy and quality, in "quality-adjusted life-years"). This was then expressed as a cost-effectiveness ratio or the cost ($) per quality-adjusted life-year (QALY) for each of the chosen hormone replacement regimens. All women of age 50 in New South Wales, Australia (n = 27,021). The analysis showed that the lifetime net increments in direct medical care costs were largely contributed by hormone drug and consultation costs. Hormone replacement was associated with increased quality-adjusted life expectancy, a large percentage of which was attributed to a relief of menopausal symptoms. Cost-effectiveness ratios ranged from under 10,000 to over a million dollars per QALY. Factors associated with improved cost-effectiveness were prolonged treatment duration, the presence of menopausal symptoms, minimum progestogen side effects (in the case of oestrogen with progestogen regimens), oestrogen use after hysterectomy and the inclusion of cardiac benefits in addition to fracture prevention. Hormone replacement therapy for symptomatic women is cost-effective when factors that enhance its efficiency are considered. Short-term treatment of asymptomatic women for prevention of osteoporotic fractures and myocardial infarction is an inefficient use of health resources. Cost-effectiveness of hormone replacement in asymptomatic women is dependent on the magnitude of cardiac benefits associated with hormone

Insight into carrier lifetime impact on band-modulation devices

Science.gov (United States)

Parihar, Mukta Singh; Lee, Kyung Hwa; Park, Hyung Jin; Lacord, Joris; Martinie, Sébastien; Barbé, Jean-Charles; Xu, Yue; El Dirani, Hassan; Taur, Yuan; Cristoloveanu, Sorin; Bawedin, Maryline

2018-05-01

A systematic study to model and characterize the band-modulation Z2-FET device is developed bringing light to the relevance of the carrier lifetime influence. This work provides guidelines to optimize the Z2-FETs for sharp switching, ESD protection, and 1T-DRAM applications. Lower carrier lifetime in the Z2-FET helps in attaining the sharp switch. We provide new insights into the correlation between generation/recombination, diffusion, electrostatic barriers and carrier lifetime.

How Much? Cost Models for Online Education.

Science.gov (United States)

Lorenzo, George

2001-01-01

Reviews some of the research being done in the area of cost models for online education. Describes a cost analysis handbook; an activity-based costing model that was based on an economic model for traditional instruction at the Indiana University Purdue University Indianapolis; and blending other costing models. (LRW)

The costs, benefits, and cost-effectiveness of interventions to reduce maternal morbidity and mortality in Mexico.

Directory of Open Access Journals (Sweden)

Delphine Hu

Full Text Available BACKGROUND: In Mexico, the lifetime risk of dying from maternal causes is 1 in 370 compared to 1 in 2,500 in the U.S. Although national efforts have been made to improve maternal services in the last decade, it is unclear if Millennium Development Goal 5--to reduce maternal mortality by three-quarters by 2015--will be met. METHODOLOGY/PRINCIPAL FINDINGS: We developed an empirically calibrated model that simulates the natural history of pregnancy and pregnancy-related complications in a cohort of 15-year-old women followed over their lifetime. After synthesizing national and sub-national trends in maternal mortality, the model was calibrated to current intervention-specific coverage levels and validated by comparing model-projected life expectancy, total fertility rate, crude birth rate and maternal mortality ratio with Mexico-specific data. Using both published and primary data, we assessed the comparative health and economic outcomes of alternative strategies to reduce maternal morbidity and mortality. A dual approach that increased coverage of family planning by 15%, and assured access to safe abortion for all women desiring elective termination of pregnancy, reduced mortality by 43% and was cost saving compared to current practice. The most effective strategy added a third component, enhanced access to comprehensive emergency obstetric care for at least 90% of women requiring referral. At a national level, this strategy reduced mortality by 75%, cost less than current practice, and had an incremental cost-effectiveness ratio of $300 per DALY relative to the next best strategy. Analyses conducted at the state level yielded similar results. CONCLUSIONS/SIGNIFICANCE: Increasing the provision of family planning and assuring access to safe abortion are feasible, complementary and cost-effective strategies that would provide the greatest benefit within a short-time frame. Incremental improvements in access to high-quality intrapartum and emergency

Nuclear lifetime measurement

International Nuclear Information System (INIS)

Guillaume, Georges

Three direct techniques of lifetime measurement are emphasized: electronic methods and two methods based on the Doppler effect (the recoil distance methods or RDM, the Doppler shift attenuation methods or DSAM). Said direct methods are concerned with the direct measurement of the radioactive decay constants of nuclear excited states. They allow lifetimes of nucleus bound states whose deexcitations occur by electromagnetic transitions, to be determined. Other methods for measuring lifetimes are also examined: microwave techniques and those involving the blocking effect in crystals (direct methods) and also various indirect methods of obtaining lifetimes (γ resonance scattering, capture reactions, inelastic electron and nucleus scattering, and Coulomb deexcitation) [fr

Handbook for cost estimating. A method for developing estimates of costs for generic actions for nuclear power plants

International Nuclear Information System (INIS)

Ball, J.R.; Cohen, S.; Ziegler, E.Z.

1984-10-01

This document provides overall guidance to assist the NRC in preparing the types of cost estimates required by the Regulatory Analysis Guidelines and to assist in the assignment of priorities in resolving generic safety issues. The Handbook presents an overall cost model that allows the cost analyst to develop a chronological series of activities needed to implement a specific regulatory requirement throughout all applicable commercial LWR power plants and to identify the significant cost elements for each activity. References to available cost data are provided along with rules of thumb and cost factors to assist in evaluating each cost element. A suitable code-of-accounts data base is presented to assist in organizing and aggregating costs. Rudimentary cost analysis methods are described to allow the analyst to produce a constant-dollar, lifetime cost for the requirement. A step-by-step example cost estimate is included to demonstrate the overall use of the Handbook

Cost-effectiveness of total hip and knee replacements for the Australian population with osteoarthritis: discrete-event simulation model.

Directory of Open Access Journals (Sweden)

Hideki Higashi

Full Text Available BACKGROUND: Osteoarthritis constitutes a major musculoskeletal burden for the aged Australians. Hip and knee replacement surgeries are effective interventions once all conservative therapies to manage the symptoms have been exhausted. This study aims to evaluate the cost-effectiveness of hip and knee replacements in Australia. To our best knowledge, the study is the first attempt to account for the dual nature of hip and knee osteoarthritis in modelling the severities of right and left joints separately. METHODOLOGY/PRINCIPAL FINDINGS: We developed a discrete-event simulation model that follows up the individuals with osteoarthritis over their lifetimes. The model defines separate attributes for right and left joints and accounts for several repeat replacements. The Australian population with osteoarthritis who were 40 years of age or older in 2003 were followed up until extinct. Intervention effects were modelled by means of disability-adjusted life-years (DALYs averted. Both hip and knee replacements are highly cost effective (AUD 5,000 per DALY and AUD 12,000 per DALY respectively under an AUD 50,000/DALY threshold level. The exclusion of cost offsets, and inclusion of future unrelated health care costs in extended years of life, did not change the findings that the interventions are cost-effective (AUD 17,000 per DALY and AUD 26,000 per DALY respectively. However, there was a substantial difference between hip and knee replacements where surgeries administered for hips were more cost-effective than for knees. CONCLUSIONS/SIGNIFICANCE: Both hip and knee replacements are cost-effective interventions to improve the quality of life of people with osteoarthritis. It was also shown that the dual nature of hip and knee OA should be taken into account to provide more accurate estimation on the cost-effectiveness of hip and knee replacements.

Fluorescence lifetime imaging of endogenous molecules in live mouse cancer models (Conference Presentation)

Science.gov (United States)

Svindrych, Zdenek; Wang, Tianxiong; Hu, Song; Periasamy, Ammasi

2017-02-01

NADH and FAD are important endogenous fluorescent coenzymes participating in key enzymatic reactions of cellular metabolism. While fluorescence intensities of NADH and FAD have been used to determine the redox state of cells and tissues, this simple approach breaks down in the case of deep-tissue intravital imaging due to depth- and wavelength-dependent light absorption and scattering. To circumvent this limitation, our research focuses on fluorescence lifetimes of two-photon excited NADH and FAD emission to study the metabolic state of live tissues. In our custom-built scanning microscope we combine tunable femtosecond Ti:sapphire laser (operating at 740 nm for NADH excitation and 890 nm for FAD excitation), two GaAsP hybrid detectors for registering individual fluorescence photons and two Becker and Hickl time correlator boards for high precision lifetime measurements. Together with our rigorous FLIM analysis approach (including image segmentation, multi-exponential decay fitting and detailed statistical analysis) we are able to detect metabolic changes in cancer xenografts (human pancreatic cancer MPanc96 cells injected subcutaneously into the ear of an immunodeficient nude mouse), relative to surrounding healthy tissue. Advantageously, with the same instrumentation we can also take high-resolution and high-contrast images of second harmonic signal (SHG) originating from collagen fibers of both the healthy skin and the growing tumor. The combination of metabolic measurements (NADH and FAD lifetime) and morphological information (collagen SHG) allows us to follow the tumor growth in live mouse model and the changes in tumor microenvironment.

Heritability of lifetime ecstasy use.

Science.gov (United States)

Verweij, Karin J H; Treur, Jorien L; Vreeker, Annabel; Brunt, Tibor M; Willemsen, Gonneke; Boomsma, Dorret I; Vink, Jacqueline M

2017-09-01

Ecstasy is a widely used psychoactive drug that users often take because they experience positive effects such as increased euphoria, sociability, elevated mood, and heightened sensations. Ecstasy use is not harmless and several immediate and long term side effects have been identified. Lifetime ecstasy use is likely to be partly influenced by genetic factors, but no twin study has determined the heritability. Here, we apply a classical twin design to a large sample of twins and siblings to estimate the heritability of lifetime ecstasy use. The sample comprised 8500 twins and siblings aged between 18 and 45 years from 5402 families registered at the Netherlands Twin Registry. In 2013-2014 participants filled out a questionnaire including a question whether they had ever used ecstasy. We used the classical twin design to partition the individual differences in liability to ecstasy use into that due to genetic, shared environmental, and residual components. Overall, 10.4% of the sample had used ecstasy during their lifetime, with a somewhat higher prevalence in males than females. Twin modelling indicated that individual differences in liability to lifetime ecstasy use are for 74% due to genetic differences between individuals, whereas shared environmental and residual factors explain a small proportion of its liability (5% and 21%, respectively). Although heritability estimates appeared to be higher for females than males, this difference was not significant. Lifetime ecstasy use is a highly heritable trait, which indicates that some people are genetically more vulnerable to start using ecstasy than others. Copyright © 2017. Published by Elsevier B.V.

Projected lifetime risks and hospital care expenditure for traumatic injury.

Science.gov (United States)

Chang, David C; Anderson, Jamie E; Kobayashi, Leslie; Coimbra, Raul; Bickler, Stephen W

2012-08-01

The lifetime risk and expected cost of trauma care would be valuable for health policy planners, but this information is currently unavailable. The cumulative incidence rates methodology, based on a cross-sectional population analysis, offers an alternative approach to prohibitively costly prospective cohort studies. Retrospective analysis of the California Office of Statewide Health Planning and Development (OSHPD) database was performed for 2008. Trauma admissions were identified by ICD-9 primary diagnosis codes 800-959, with certain exclusions. Cumulative incidence rates were calculated as the cumulative summation of incidence risks sequentially across age groups. A total of 2.2 million admissions were identified, with mean age of 63.8 y, 49.6% men, 82.8% Whites, 5.7% Blacks, 11.3% Hispanics, and 3.1% Asians. The cumulative incidence rate for patients older than age 85 y was 1119 per 10,000 people, with the majority of risk in the elderly, compared with 24,325 per 10,000 people for all-cause hospitalizations. The rates were 946 for men, 1079 for women, 999 for non-Hispanic Whites, 568 for Blacks, 577 for Hispanics, and 395 for Asians, per 10,000 population. The cumulative expected hospital charge was $6538, compared with $81,257 for all-cause hospitalizations. The cumulative lifetime risk of trauma/injury requiring hospitalization for a person living to age 85 y in California is 11.2%, accounting for 4.6% of expected lifetime hospitalizations, but accounting for 8.0% of expected lifetime hospital expenditures. Risk of trauma is significant in the elderly. The total expenditure for all trauma hospitalizations in California was $7.62 billion in 2008. Copyright © 2012 Elsevier Inc. All rights reserved.

Preliminary Multivariable Cost Model for Space Telescopes

Science.gov (United States)

Stahl, H. Philip

2010-01-01

Parametric cost models are routinely used to plan missions, compare concepts and justify technology investments. Previously, the authors published two single variable cost models based on 19 flight missions. The current paper presents the development of a multi-variable space telescopes cost model. The validity of previously published models are tested. Cost estimating relationships which are and are not significant cost drivers are identified. And, interrelationships between variables are explored

GUT scale threshold corrections in a complete supersymmetric SO(10) model: αs(MZ) versus proton lifetime

International Nuclear Information System (INIS)

Lucas, V.; Raby, S.

1996-01-01

We show that one-loop GUT scale threshold corrections to gauge couplings are a significant constraint on the GUT symmetry-breaking sector of the theory. The one-loop threshold corrections relate the prediction for α s (M Z ) to the proton lifetime. We have calculated these corrections in a new complete SO(10) SUSY GUT. The results are consistent with the low-energy measurement of α s (M Z ). We have also calculated the proton lifetime and branching ratios in this model. We show that proton decay rates provide a powerful test for theories of fermion masses. copyright 1996 The American Physical Society

Method for developing cost estimates for generic regulatory requirements

International Nuclear Information System (INIS)

1985-01-01

The NRC has established a practice of performing regulatory analyses, reflecting costs as well as benefits, of proposed new or revised generic requirements. A method had been developed to assist the NRC in preparing the types of cost estimates required for this purpose and for assigning priorities in the resolution of generic safety issues. The cost of a generic requirement is defined as the net present value of total lifetime cost incurred by the public, industry, and government in implementing the requirement for all affected plants. The method described here is for commercial light-water-reactor power plants. Estimating the cost for a generic requirement involves several steps: (1) identifying the activities that must be carried out to fully implement the requirement, (2) defining the work packages associated with the major activities, (3) identifying the individual elements of cost for each work package, (4) estimating the magnitude of each cost element, (5) aggregating individual plant costs over the plant lifetime, and (6) aggregating all plant costs and generic costs to produce a total, national, present value of lifetime cost for the requirement. The method developed addresses all six steps. In this paper, we discuss on the first three

Solid rocket motor cost model

Science.gov (United States)

Harney, A. G.; Raphael, L.; Warren, S.; Yakura, J. K.

1972-01-01

A systematic and standardized procedure for estimating life cycle costs of solid rocket motor booster configurations. The model consists of clearly defined cost categories and appropriate cost equations in which cost is related to program and hardware parameters. Cost estimating relationships are generally based on analogous experience. In this model the experience drawn on is from estimates prepared by the study contractors. Contractors' estimates are derived by means of engineering estimates for some predetermined level of detail of the SRM hardware and program functions of the system life cycle. This method is frequently referred to as bottom-up. A parametric cost analysis is a useful technique when rapid estimates are required. This is particularly true during the planning stages of a system when hardware designs and program definition are conceptual and constantly changing as the selection process, which includes cost comparisons or trade-offs, is performed. The use of cost estimating relationships also facilitates the performance of cost sensitivity studies in which relative and comparable cost comparisons are significant.

Lifetimes of some b-flavored hadrons

International Nuclear Information System (INIS)

Stone, S.

2014-06-01

Recent measurements of lifetimes of some b-flavored hadrons are presented and interpreted in the context of theoretical models, especially the Heavy Quark Expansion. Decay widths and decay width differences in the B s 0 - B-bar s 0 system are discussed from the studies of decays into the final states J/ψK + K - , J/ψπ + π - , D s + D s - , K + K - and D s ± π ± . Lifetime measurements of the baryons Λ b 0 , Ξ b - , Ξ b 0 , and Ω b - are also shown. (author)

Cost analysis of fixed-dose combination of dutasteride and tamsulosin compared with concomitant dutasteride and tamsulosin monotherapy in patients with benign prostatic hyperplasia in Canada

Science.gov (United States)

Sayani, Amyn; Ismaila, Afisi; Walker, Anna; Posnett, John; Laroche, Bruno; Nickel, J. Curtis; Su, Zhen

2014-01-01

Introduction: We estimate the lifetime cost of treatment for moderate/severe symptoms associated with benign prostatic hyperplasia (BPH) in a cohort of Canadian men aged 50 to 59, and we evaluate the costs of 2 daily bioequivalent treatment options: fixed-dose combination (FDC) of dutasteride (0.5 mg) and tamsulosin (0.4 mg), or concomitant administration of dutasteride (0.5 mg) and tamsulosin (0.4 mg) monotherapies. Methods: The expected lifetime costs were estimated by modelling the incidence of acute urinary retention (AUR), BPH-related surgery and clinical progression over a patient’s lifetime (up to 25 years). A model was developed to simulate clinical events over time, based on a discrete Markov process with 6 mutually exclusive health states and annual cycle length. Results: The estimated lifetime budget cost for the cohort of 374 110 men aged 50 to 59 in Canada is between $6.35 billion and $7.60 billion, equivalent to between $16 979 and $20 315 per patient with moderate/severe symptoms associated with BPH. Costs are lower for FDC treatment, with the net difference in lifetime budget impact between the 2 treatment regimens at $1.25 billion. In this analysis, the true costs of BPH in Canada are underestimated for 2 main reasons: (1) to make the analysis tractable, it is restricted to a cohort aged 50 to 59, whereas BPH can affect all men; and (2) a closed cohort approach does not include the costs of new (incident) cases. Conclusion: Canadian clinical guidelines recommend the use of the combination of tamsulosin and dutasteride for men with moderate/severe symptoms associated with BPH and enlarged prostate volume. This analysis, using a representational patient group, suggests that the FDC is a more cost-effective treatment option for BPH. PMID:24454593

Modelling the cost-effectiveness of human milk and breastfeeding in preterm infants in the United Kingdom.

Science.gov (United States)

Mahon, James; Claxton, Lindsay; Wood, Hannah

2016-12-01

To estimate the cost savings and health benefits in the UK NHS that could be achieved if human milk usage in the NICU was increased. A systematic review established the disease areas with the strong sources of evidence of the short, medium and long-term benefits of human milk for preterm infants as opposed to the use of formula milk. The analysis assessed the economic impact of reducing rates of necrotising enterocolitis, sepsis, sudden infant death syndrome, leukaemia, otitis media, obesity and neurodevelopmental impairment. Based on the number of preterm babies born in 2013, if 100% of premature infants being fed mother's milk could be achieved in the NICU, the total lifetime cost savings to the NHS due to improved health outcomes is estimated to be £46.7 million (£30.1 million in the first year) with a total lifetime QALY gain of 10,594, There would be 238 fewer deaths due to neonatal infections and SIDS, resulting in a reduction of approximately £153.4 million in lifetime productivity. Sensitivity analyses indicated that results were robust to a wide range of inputs. This analysis established that increasing the use of human milk in NICUs in the UK would lead to cost savings to the NHS. More research is needed on the medium and long term health and economic outcomes associated with breastfeeding preterm infants, and the differences between mother's own and donor breast milk.

Cost-effectiveness of EOB-MRI for Hepatocellular Carcinoma in Japan.

Science.gov (United States)

Nishie, Akihiro; Goshima, Satoshi; Haradome, Hiroki; Hatano, Etsuro; Imai, Yasuharu; Kudo, Masatoshi; Matsuda, Masanori; Motosugi, Utaroh; Saitoh, Satoshi; Yoshimitsu, Kengo; Crawford, Bruce; Kruger, Eliza; Ball, Graeme; Honda, Hiroshi

2017-04-01

The objective of the study was to evaluate the cost-effectiveness of gadoxetic acid-enhanced magnetic resonance imaging (EOB-MRI) in the diagnosis and treatment of hepatocellular carcinoma (HCC) in Japan compared with extracellular contrast media-enhanced MRI (ECCM-MRI) and contrast media-enhanced computed tomography (CE-CT) scanning. A 6-stage Markov model was developed to estimate lifetime direct costs and clinical outcomes associated with EOB-MRI. Diagnostic sensitivity and specificity, along with clinical data on HCC survival, recurrence, treatment patterns, costs, and health state utility values, were derived from predominantly Japanese publications. Parameters unavailable from publications were estimated in a Delphi panel of Japanese clinical experts who also confirmed the structure and overall approach of the model. Sensitivity analyses, including one-way, probabilistic, and scenario analyses, were conducted to account for uncertainty in the results. Over a lifetime horizon, EOB-MRI was associated with lower direct costs (¥2,174,869) and generated a greater number of quality-adjusted life years (QALYs) (9.502) than either ECCM-MRI (¥2,365,421, 9.303 QALYs) or CE-CT (¥2,482,608, 9.215 QALYs). EOB-MRI was superior to the other diagnostic strategies considered, and this finding was robust over sensitivity and scenario analyses. A majority of the direct costs associated with HCC in Japan were found to be costs of treatment. The model results revealed the superior cost-effectiveness of the EOB-MRI diagnostic strategy compared with ECCM-MRI and CE-CT. EOB-MRI could be the first-choice imaging modality for medical care of HCC among patients with hepatitis or liver cirrhosis in Japan. Widespread implementation of EOB-MRI could reduce health care expenditures, particularly downstream treatment costs, associated with HCC. Copyright © 2017 Elsevier HS Journals, Inc. All rights reserved.

Simulation of quitting smoking in the military shows higher lifetime medical spending more than offset by productivity gains.

Science.gov (United States)

Yang, Wenya; Dall, Timothy M; Zhang, Yiduo; Zhang, Shiping; Arday, David R; Dorn, Patricia W; Jain, Anjali

2012-12-01

Despite the documented benefits of quitting smoking, studies have found that smokers who quit may have higher lifetime medical costs, in part because of increased risk for medical conditions, such as type 2 diabetes, brought on by associated weight gain. Using a simulation model and data on 612,332 adult smokers in the US Department of Defense's TRICARE Prime health plan in 2008, we estimated that cessation accompanied by weight gain would increase average life expectancy by 3.7 years, and that the average lifetime reduction in medical expenditures from improved health ($5,600) would be offset by additional expenditures resulting from prolonged life ($7,300). Results varied by age and sex: For females ages 18-44 at time of cessation, there would be net savings of $1,200 despite additional medical expenditures from prolonged life. Avoidance of weight gain after quitting smoking would increase average life expectancy by four additional months and reduce mean extra spending resulting from prolonged life by $700. Overall, the average net lifetime health care cost increase of $1,700 or less per ex-smoker would be modest and, for employed people, more than offset by even one year's worth of productivity gains. These results boost the case for smoking cessation programs in the military in particular, along with not selling cigarettes in commissaries or at reduced prices.

Hadronization, spin and lifetimes

International Nuclear Information System (INIS)

Grossman, Yuval; Nachshon, Itay

2008-01-01

Measurements of lifetimes can be done in two ways. For very short lived particles, the width can be measured. For long lived ones, the lifetime can be directly measured, for example, using a displaced vertex. Practically, the lifetime cannot be extracted for particles with intermediate lifetimes. We show that for such cases information about the lifetime can be extracted for heavy colored particles that can be produced with known polarization. For example, a t-like particle with intermediate lifetime hadronizes into a superposition of the lowest two hadronic states, T* and T (the equivalent of B* and B). Depolarization effects are governed by time scales that are much longer than the hadronization time scale, Λ QCD -1 . After a time of order 1/Δm, with Δm≡m(T*)-m(T), half of the initial polarization is lost. The polarization is totally lost after a time of order 1/Γ γ , with Γ γ = Γ(T* → Tγ). Thus, by comparing the initial and final polarization, we get information on the particle's lifetime.

Bayesian models for cost-effectiveness analysis in the presence of structural zero costs.

Science.gov (United States)

Baio, Gianluca

2014-05-20

Bayesian modelling for cost-effectiveness data has received much attention in both the health economics and the statistical literature, in recent years. Cost-effectiveness data are characterised by a relatively complex structure of relationships linking a suitable measure of clinical benefit (e.g. quality-adjusted life years) and the associated costs. Simplifying assumptions, such as (bivariate) normality of the underlying distributions, are usually not granted, particularly for the cost variable, which is characterised by markedly skewed distributions. In addition, individual-level data sets are often characterised by the presence of structural zeros in the cost variable. Hurdle models can be used to account for the presence of excess zeros in a distribution and have been applied in the context of cost data. We extend their application to cost-effectiveness data, defining a full Bayesian specification, which consists of a model for the individual probability of null costs, a marginal model for the costs and a conditional model for the measure of effectiveness (given the observed costs). We presented the model using a working example to describe its main features. © 2013 The Authors. Statistics in Medicine published by John Wiley & Sons, Ltd.

Societal Costs of Micronutrient Deficiencies in 6- to 59-month-old Children in Pakistan.

Science.gov (United States)

Wieser, Simon; Brunner, Beatrice; Tzogiou, Christina; Plessow, Rafael; Zimmermann, Michael B; Farebrother, Jessica; Soofi, Sajid; Bhatti, Zaid; Ahmed, Imran; Bhutta, Zulfiqar A

2017-12-01

In Pakistan, nearly half of children younger than 5 years are stunted, and 1 in 3 is underweight. Micronutrient deficiencies, a less visible form of undernutrition, are also endemic. They may lead to increased morbidity and mortality as well as to impaired cognitive and physical development. To estimate the lifetime costs of micronutrient deficiencies in Pakistani children aged between 6 and 59 months. We develop a health economic model of the lifetime health and cost consequences of iodine, iron, vitamin A, and zinc deficiencies. We assess medical costs, production losses in terms of future incomes lost, and disability-adjusted life-years (DALYs). The estimation is based on large population surveys, information on the health consequences of micronutrient deficiencies extracted from randomized trials, and a variety of other sources. Total societal costs amount to US$46 million in medical costs, US$3,222 million in production losses, and 3.4 million DALYs. Costs are dominated by the impaired cognitive development induced by iron-deficiency anemia in 6- to 23-month-old children and the mortality caused by vitamin A deficiency. Costs are substantially higher in poorer households. Societal costs amounted to 1.44% of gross domestic product and 4.45% of DALYs in Pakistan in 2013. These costs hinder the country's development. They could be eliminated by improved nutrition of 6- to 59-month-old children and public health measures. Our results may contribute to the design of cost-effective interventions aiming to reduce micronutrient deficiencies in early childhood and their lifetime consequences.

A model for predicting the lifetimes of Grade-2 titanium nuclear waste containers

Energy Technology Data Exchange (ETDEWEB)

Shoesmith, D W; Ikeda, B M; Bailey, M G; Quinn, M J; LeNeveu, D M [Atomic Energy of Canada Ltd., Pinawa, MB (Canada). Whiteshell Labs.

1995-08-01

The development of a model to predict the lifetimes of Grade-2 titanium containers for nuclear fuel waste is described. This model assumes that the corrosion processes most likely to lead to container failure are crevice corrosion, hydrogen-induced cracking and general corrosion. Because of the expected evolution of waste vault conditions from initially warm (<{approx} 100 deg C) and oxidizing to eventually cool (<30 deg C) and non-oxiding, the period for which crevice corrosion can propagate will be limited by repassivation, and long container lifetimes will be achieved since the rate of general corrosion is extremely low. However, in the model presented, not only is it assumed that crevices will initiate rapidly on all containers, but also that the propagation of these crevices will continue indefinitely since conditions will remain sufficiently oxiding for repassivation to be avoided. The mathematical development of the model is described in detail. A simple ramped distribution is used to describe the failures due to the presence of initial defects. For crevice corrosion the propagation rates are assumed to be normally distributed and to be determined predominantly by temperature. The temperature dependence of the crevice propagation rate is determined from the calculated cooling profiles for the containers and an experimentally determined Arrhenius relationship for crevice propagation rates. The cooling profiles are approximated by double or single step functions, depending on the location of the container within the vault. The experimental data upon which this model is based is extensively reviewed. This review includes descriptions of the available data to describe and quantify the processes of general corrosion, crevice corrosion and hydrogen-induced cracking. For crevice corrosion and hydrogen-induced cracking the results of studies on both Grades-2 and -12 are presented. Also, the effects of impurities in the Grade-2 material are discussed.

Lifetime of heavy flavour particles

International Nuclear Information System (INIS)

Lueth, V.

1985-10-01

Recent measurements of the lifetime of the tau leptons and charm and beauty hadrons are reviewed and their significance for the couplings of the charged weak current, flavour mixing, and models relating quarks to hadron decay are discussed. 70 refs., 17 figs., 5 tabs

Cost-effectiveness of interventions to promote physical activity: a modelling study.

Directory of Open Access Journals (Sweden)

Linda J Cobiac

2009-07-01

Full Text Available BACKGROUND: Physical inactivity is a key risk factor for chronic disease, but a growing number of people are not achieving the recommended levels of physical activity necessary for good health. Australians are no exception; despite Australia's image as a sporting nation, with success at the elite level, the majority of Australians do not get enough physical activity. There are many options for intervention, from individually tailored advice, such as counselling from a general practitioner, to population-wide approaches, such as mass media campaigns, but the most cost-effective mix of interventions is unknown. In this study we evaluate the cost-effectiveness of interventions to promote physical activity. METHODS AND FINDINGS: From evidence of intervention efficacy in the physical activity literature and evaluation of the health sector costs of intervention and disease treatment, we model the cost impacts and health outcomes of six physical activity interventions, over the lifetime of the Australian population. We then determine cost-effectiveness of each intervention against current practice for physical activity intervention in Australia and derive the optimal pathway for implementation. Based on current evidence of intervention effectiveness, the intervention programs that encourage use of pedometers (Dominant and mass media-based community campaigns (Dominant are the most cost-effective strategies to implement and are very likely to be cost-saving. The internet-based intervention program (AUS$3,000/DALY, the GP physical activity prescription program (AUS$12,000/DALY, and the program to encourage more active transport (AUS$20,000/DALY, although less likely to be cost-saving, have a high probability of being under a AUS$50,000 per DALY threshold. GP referral to an exercise physiologist (AUS$79,000/DALY is the least cost-effective option if high time and travel costs for patients in screening and consulting an exercise physiologist are considered

Predicting sample lifetimes in creep fracture of heterogeneous materials

Science.gov (United States)

Koivisto, Juha; Ovaska, Markus; Miksic, Amandine; Laurson, Lasse; Alava, Mikko J.

2016-08-01

Materials flow—under creep or constant loads—and, finally, fail. The prediction of sample lifetimes is an important and highly challenging problem because of the inherently heterogeneous nature of most materials that results in large sample-to-sample lifetime fluctuations, even under the same conditions. We study creep deformation of paper sheets as one heterogeneous material and thus show how to predict lifetimes of individual samples by exploiting the "universal" features in the sample-inherent creep curves, particularly the passage to an accelerating creep rate. Using simulations of a viscoelastic fiber bundle model, we illustrate how deformation localization controls the shape of the creep curve and thus the degree of lifetime predictability.

The Impact of Mission Profile Models on the Predicted Lifetime of IGBT Modules in the Modular Multilevel Converter

DEFF Research Database (Denmark)

Zhang, Yi; Wang, Huai; Wang, Zhongxu

2017-01-01

and electrical power modeling methods on the estimated lifetime of IGBT modules in an MMC for offshore wind power application. In a 30 MW MMC case study, an annual wind speed profile with a resolution of 1 s/data, 10 minute/data, and 1 hour/data are considered, respectively. A method to re-generate higher......The reliability aspect study of Modular Multilevel Converter (MMC) is of great interest in industry applications, such as offshore wind. Lifetime prediction of key components is an important tool to design MMC with fulfilled reliability specifications. While many efforts have been made...... to the lifetime prediction of IGBT modules in renewable energy applications by considering long-term varying operation conditions (i.e., mission profile), the justifications of using the associated mission profiles are still missed. This paper investigates the impact of mission profile data resolutions...

A Satellite Mortality Study to Support Space Systems Lifetime Prediction

Science.gov (United States)

Fox, George; Salazar, Ronald; Habib-Agahi, Hamid; Dubos, Gregory

2013-01-01

Estimating the operational lifetime of satellites and spacecraft is a complex process. Operational lifetime can differ from mission design lifetime for a variety of reasons. Unexpected mortality can occur due to human errors in design and fabrication, to human errors in launch and operations, to random anomalies of hardware and software or even satellite function degradation or technology change, leading to unrealized economic or mission return. This study focuses on data collection of public information using, for the first time, a large, publically available dataset, and preliminary analysis of satellite lifetimes, both operational lifetime and design lifetime. The objective of this study is the illustration of the relationship of design life to actual lifetime for some representative classes of satellites and spacecraft. First, a Weibull and Exponential lifetime analysis comparison is performed on the ratio of mission operating lifetime to design life, accounting for terminated and ongoing missions. Next a Kaplan-Meier survivor function, standard practice for clinical trials analysis, is estimated from operating lifetime. Bootstrap resampling is used to provide uncertainty estimates of selected survival probabilities. This study highlights the need for more detailed databases and engineering reliability models of satellite lifetime that include satellite systems and subsystems, operations procedures and environmental characteristics to support the design of complex, multi-generation, long-lived space systems in Earth orbit.

Costs and benefits of individuals conceived after IVF: a net tax evaluation in The Netherlands.

Science.gov (United States)

Moolenaar, L M; Connolly, M; Huisman, B; Postma, M J; Hompes, P G A; van der Veen, F; Mol, B W J

2014-02-01

This study evaluated the lifetime future net tax revenues from individuals conceived after IVF relative to those naturally conceived. A model based on the method of generational accounting was developed to evaluate investments in IVF. Calculations were based on average investments paid and received from the government by an individual. All costs were discounted to their net present values and adjusted for survival. The lifetime net present value of IVF-conceived individuals was -€81,374 (the minus sign reflecting negative net present value). The lifetime net present value of IVF-conceived men and women were -€47,091 and -€123,177, respectively. The lifetime net present value of naturally conceived individuals was -€70,392; respective amounts for men and women were -€36,109 and -€112,195. The model was most sensitive to changes in the growth of healthcare costs, economic growth and the discount rate. Therefore, it is concluded that, similarly to naturally conceived individuals in the Netherlands, IVF-conceived individuals have negative discounted net tax revenue at the end of life. The analytic framework described here undervalues the incremental value of an additional birth because it only considers the fiscal consequences of life and does not take into consideration broader macroeconomic benefits. This study evaluated the lifetime future net tax revenues from individuals conceived after IVF relative those naturally conceived. A model based on the method of generational accounting to evaluate investments in IVF was used. Calculations were based on average investments paid and received from the government by an individual. The lifetime net present value of IVF-conceived individuals was -€81,374 (the minus sign reflecting negative net present value). The lifetime net present value of IVF-conceived men and women were -€47,091 and -€123,177, respectively. The lifetime net present value of naturally conceived individuals was -€70,392; respective

Cost-effectiveness analysis of trastuzumab in the adjuvant setting for treatment of HER2-positive breast cancer.

Science.gov (United States)

Garrison, Louis P; Lubeck, Deborah; Lalla, Deepa; Paton, Virginia; Dueck, Amylou; Perez, Edith A

2007-08-01

Adding trastuzumab to adjuvant chemotherapy provides significant clinical benefit in patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer. A cost-effectiveness analysis was performed to assess clinical and economic implications of adding trastuzumab to adjuvant chemotherapy, based upon joint analysis of NSABP B-31 and NCCTG N9831 trials. A Markov model with 4 health states was used to estimate the cost utility for a 50-year-old woman on the basis of trial results through 4 years and estimates of long-term recurrence and death based on a meta-analysis of trials. From 6 years onward, rates of recurrence and death were assumed to be the same in both trastuzumab and chemotherapy-only arms. Incremental costs were estimated for diagnostic and treatment-related costs. Analyses were from payer and societal perspectives, and these analyses were projected to lifetime and 20-year horizons. Over a lifetime, the projected cost of trastuzumab per quality-adjusted life year (QALY; discount rate 3%) gained was 26,417 dollars (range 9,104 dollars-69,340 dollars under multiway sensitivity analysis). Discounted incremental lifetime cost was 44,923 dollars, and projected life expectancy was 3 years longer for patients who received trastuzumab (19.4 years vs 16.4 years). During a 20-year horizon, the projected cost of adding trastuzumab to chemotherapy was 34,201 dollars per QALY gained. Key cost-effectiveness drivers were discount rate, trastuzumab price, and probability of metastasis. The cost-effectiveness result was robust to sensitivity analysis. Trastuzumab for adjuvant treatment of early stage breast cancer was projected to be cost effective over a lifetime horizon, achieving a cost-effectiveness ratio below that of many widely accepted oncology treatments. (c) 2007 American Cancer Society.

The Launch Systems Operations Cost Model

Science.gov (United States)

Prince, Frank A.; Hamaker, Joseph W. (Technical Monitor)

2001-01-01

One of NASA's primary missions is to reduce the cost of access to space while simultaneously increasing safety. A key component, and one of the least understood, is the recurring operations and support cost for reusable launch systems. In order to predict these costs, NASA, under the leadership of the Independent Program Assessment Office (IPAO), has commissioned the development of a Launch Systems Operations Cost Model (LSOCM). LSOCM is a tool to predict the operations & support (O&S) cost of new and modified reusable (and partially reusable) launch systems. The requirements are to predict the non-recurring cost for the ground infrastructure and the recurring cost of maintaining that infrastructure, performing vehicle logistics, and performing the O&S actions to return the vehicle to flight. In addition, the model must estimate the time required to cycle the vehicle through all of the ground processing activities. The current version of LSOCM is an amalgamation of existing tools, leveraging our understanding of shuttle operations cost with a means of predicting how the maintenance burden will change as the vehicle becomes more aircraft like. The use of the Conceptual Operations Manpower Estimating Tool/Operations Cost Model (COMET/OCM) provides a solid point of departure based on shuttle and expendable launch vehicle (ELV) experience. The incorporation of the Reliability and Maintainability Analysis Tool (RMAT) as expressed by a set of response surface model equations gives a method for estimating how changing launch system characteristics affects cost and cycle time as compared to today's shuttle system. Plans are being made to improve the model. The development team will be spending the next few months devising a structured methodology that will enable verified and validated algorithms to give accurate cost estimates. To assist in this endeavor the LSOCM team is part of an Agency wide effort to combine resources with other cost and operations professionals to

Specifying the ovarian cancer risk threshold of 'premenopausal risk-reducing salpingo-oophorectomy' for ovarian cancer prevention: a cost-effectiveness analysis.

Science.gov (United States)

Manchanda, Ranjit; Legood, Rosa; Antoniou, Antonis C; Gordeev, Vladimir S; Menon, Usha

2016-09-01

Risk-reducing salpingo-oophorectomy (RRSO) is the most effective intervention to prevent ovarian cancer (OC). It is only available to high-risk women with >10% lifetime OC risk. This threshold has not been formally tested for cost-effectiveness. To specify the OC risk thresholds for RRSO being cost-effective for preventing OC in premenopausal women. The costs as well as effects of surgical prevention ('RRSO') were compared over a lifetime with 'no RRSO' using a decision analysis model. RRSO was undertaken in premenopausal women >40 years. The model was evaluated at lifetime OC risk levels: 2%, 4%, 5%, 6%, 8% and 10%. Costs and outcomes are discounted at 3.5%. Uncertainty in the model was assessed using both deterministic sensitivity analysis and probabilistic sensitivity analysis (PSA). Outcomes included in the analyses were OC, breast cancer (BC) and additional deaths from coronary heart disease. Total costs and effects were estimated in terms of quality-adjusted life-years (QALYs); incidence of OC and BC; as well as incremental cost-effectiveness ratio (ICER). Published literature, Nurses Health Study, British National Formulary, Cancer Research UK, National Institute for Health and Care Excellence guidelines and National Health Service reference costs. The time horizon is lifetime and perspective: payer. Premenopausal RRSO is cost-effective at 4% OC risk (life expectancy gained=42.7 days, ICER=£19 536/QALY) with benefits largely driven by reduction in BC risk. RRSO remains cost-effective at >8.2% OC risk without hormone replacement therapy (ICER=£29 071/QALY, life expectancy gained=21.8 days) or 6%if BC risk reduction=0 (ICER=£27 212/QALY, life expectancy gained=35.3 days). Sensitivity analysis indicated results are not impacted much by costs of surgical prevention or treatment of OC/ BC or cardiovascular disease. However, results were sensitive to RRSO utility scores. Additionally, 37%, 61%, 74%, 84%, 96% and 99.5% simulations on PSA are cost

User Delay Cost Model and Facilities Maintenance Cost Model for a Terminal Control Area : Volume 3. User's Manual and Program Documentation for the Facilities Maintenance Cost Model

Science.gov (United States)

1978-05-01

The Facilities Maintenance Cost Model (FMCM) is an analytic model designed to calculate expected annual labor costs of maintenance within a given FAA maintenance sector. The model is programmed in FORTRAN IV and has been demonstrated on the CDC Krono...

Recoil distance lifetime measurements in 122,124Xe

Science.gov (United States)

Govil, I. M.; Kumar, A.; Iyer, H.; Li, H.; Garg, U.; Ghugre, S. S.; Johnson, T.; Kaczarowski, R.; Kharraja, B.; Naguleswaran, S.; Walpe, J. C.

1998-02-01

Lifetimes of the lower-excited states in 122,124Xe are measured using the recoil-distance Doppler-shift technique. The reactions 110Pd(16O,4n)122Xe and 110Pd(18O,4n)124Xe at a beam energy of 66 MeV were used for this experiment. The lifetimes of the 2+, 4+, 6+, and 8+ states of the ground state band were extracted using the computer code LIFETIME including the corrections due to the side feeding and the nuclear deorientation effects. The lifetime of the 2+ state in 122Xe agrees with the recoil distance method (RDM) measurements but for the 124Xe it does not agree with the RDM measurements but agrees with the Coulomb-excitation experiment. The measured B(E2) values for both the nuclei are compared with the standard algebraic and the multishell models.

Assessing the Battery Cost at Which Plug-In Hybrid Medium-Duty Parcel Delivery Vehicles Become Cost-Effective

Energy Technology Data Exchange (ETDEWEB)

Ramroth, L. A.; Gonder, J. D.; Brooker, A. D.

2013-04-01

The National Renewable Energy Laboratory (NREL) validated diesel-conventional and diesel-hybrid medium-duty parcel delivery vehicle models to evaluate petroleum reductions and cost implications of hybrid and plug-in hybrid diesel variants. The hybrid and plug-in hybrid variants are run on a field data-derived design matrix to analyze the effect of drive cycle, distance, engine downsizing, battery replacements, and battery energy on fuel consumption and lifetime cost. For an array of diesel fuel costs, the battery cost per kilowatt-hour at which the hybridized configuration becomes cost-effective is calculated. This builds on a previous analysis that found the fuel savings from medium duty plug-in hybrids more than offset the vehicles' incremental price under future battery and fuel cost projections, but that they seldom did so under present day cost assumptions in the absence of purchase incentives. The results also highlight the importance of understanding the application's drive cycle specific daily distance and kinetic intensity.

Metallized Film Capacitor Lifetime Evaluation and Failure Mode Analysis

CERN Document Server

Gallay, R.

2015-06-15

One of the main concerns for power electronic engineers regarding capacitors is to predict their remaining lifetime in order to anticipate costly failures or system unavailability. This may be achieved using a Weibull statistical law combined with acceleration factors for the temperature, the voltage, and the humidity. This paper discusses the different capacitor failure modes and their effects and consequences.

Modelled Cost-Effectiveness of a Package Size Cap and a Kilojoule Reduction Intervention to Reduce Energy Intake from Sugar-Sweetened Beverages in Australia

Science.gov (United States)

Mantilla Herrera, Ana Maria; Neal, Bruce; Zheng, Miaobing; Lal, Anita; Sacks, Gary

2017-01-01

Interventions targeting portion size and energy density of food and beverage products have been identified as a promising approach for obesity prevention. This study modelled the potential cost-effectiveness of: a package size cap on single-serve sugar sweetened beverages (SSBs) >375 mL (package size cap), and product reformulation to reduce energy content of packaged SSBs (energy reduction). The cost-effectiveness of each intervention was modelled for the 2010 Australia population using a multi-state life table Markov model with a lifetime time horizon. Long-term health outcomes were modelled from calculated changes in body mass index to their impact on Health-Adjusted Life Years (HALYs). Intervention costs were estimated from a limited societal perspective. Cost and health outcomes were discounted at 3%. Total intervention costs estimated in AUD 2010 were AUD 210 million. Both interventions resulted in reduced mean body weight (package size cap: 0.12 kg; energy reduction: 0.23 kg); and HALYs gained (package size cap: 73,883; energy reduction: 144,621). Cost offsets were estimated at AUD 750.8 million (package size cap) and AUD 1.4 billion (energy reduction). Cost-effectiveness analyses showed that both interventions were “dominant”, and likely to result in long term cost savings and health benefits. A package size cap and kJ reduction of SSBs are likely to offer excellent “value for money” as obesity prevention measures in Australia. PMID:28878175

Cost-Effectiveness of Sacubitril-Valsartan Combination Therapy Compared With Enalapril for the Treatment of Heart Failure With Reduced Ejection Fraction.

Science.gov (United States)

King, Jordan B; Shah, Rashmee U; Bress, Adam P; Nelson, Richard E; Bellows, Brandon K

2016-05-01

The objective of this study was to determine the cost-effectiveness and cost per quality-adjusted life year (QALY) gained of sacubitril-valsartan relative to enalapril for treatment of heart failure with reduced ejection fraction (HFrEF). Compared with enalapril, combination angiotensin receptor-neprilysin inhibition (ARNI), as is found in sacubitril-valsartan, reduces cardiovascular death and heart failure hospitalization rates in patients with HFrEF. Using a Markov model, costs, effects, and cost-effectiveness were estimated for sacubitril-valsartan and enalapril therapies for the treatment of HFrEF. Patients were 60 years of age at model entry and were modeled over a lifetime (40 years) from a third-party payer perspective. Clinical probabilities were derived predominantly from PARADIGM-HF (Prospective Comparison of ARNI With ACEI to Determine Impact on Global Mortality and Morbidity in Heart Failure). All costs and effects were discounted at a 3% rate annually and are presented in 2015 U.S. dollars. In the base case, sacubitril-valsartan, compared with enalapril, was more costly ($60,391 vs. $21,758) and more effective (6.49 vs. 5.74 QALYs) over a lifetime. The cost-effectiveness of sacubitril-valsartan was highly dependent on duration of treatment, ranging from $249,411 per QALY at 3 years to $50,959 per QALY gained over a lifetime. Sacubitril-valsartan may be a cost-effective treatment option depending on the willingness-to-pay threshold. Future investigations should incorporate real-world evidence with sacubitril-valsartan to further inform decision making. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Characterization of Initial Parameter Information for Lifetime Prediction of Electronic Devices.

Science.gov (United States)

Li, Zhigang; Liu, Boying; Yuan, Mengxiong; Zhang, Feifei; Guo, Jiaqiang

2016-01-01

Newly manufactured electronic devices are subject to different levels of potential defects existing among the initial parameter information of the devices. In this study, a characterization of electromagnetic relays that were operated at their optimal performance with appropriate and steady parameter values was performed to estimate the levels of their potential defects and to develop a lifetime prediction model. First, the initial parameter information value and stability were quantified to measure the performance of the electronics. In particular, the values of the initial parameter information were estimated using the probability-weighted average method, whereas the stability of the parameter information was determined by using the difference between the extrema and end points of the fitting curves for the initial parameter information. Second, a lifetime prediction model for small-sized samples was proposed on the basis of both measures. Finally, a model for the relationship of the initial contact resistance and stability over the lifetime of the sampled electromagnetic relays was proposed and verified. A comparison of the actual and predicted lifetimes of the relays revealed a 15.4% relative error, indicating that the lifetime of electronic devices can be predicted based on their initial parameter information.

Characterization of Initial Parameter Information for Lifetime Prediction of Electronic Devices.

Directory of Open Access Journals (Sweden)

Zhigang Li

Full Text Available Newly manufactured electronic devices are subject to different levels of potential defects existing among the initial parameter information of the devices. In this study, a characterization of electromagnetic relays that were operated at their optimal performance with appropriate and steady parameter values was performed to estimate the levels of their potential defects and to develop a lifetime prediction model. First, the initial parameter information value and stability were quantified to measure the performance of the electronics. In particular, the values of the initial parameter information were estimated using the probability-weighted average method, whereas the stability of the parameter information was determined by using the difference between the extrema and end points of the fitting curves for the initial parameter information. Second, a lifetime prediction model for small-sized samples was proposed on the basis of both measures. Finally, a model for the relationship of the initial contact resistance and stability over the lifetime of the sampled electromagnetic relays was proposed and verified. A comparison of the actual and predicted lifetimes of the relays revealed a 15.4% relative error, indicating that the lifetime of electronic devices can be predicted based on their initial parameter information.

The Shuttle Cost and Price model

Science.gov (United States)

Leary, Katherine; Stone, Barbara

1983-01-01

The Shuttle Cost and Price (SCP) model was developed as a tool to assist in evaluating major aspects of Shuttle operations that have direct and indirect economic consequences. It incorporates the major aspects of NASA Pricing Policy and corresponds to the NASA definition of STS operating costs. An overview of the SCP model is presented and the cost model portion of SCP is described in detail. Selected recent applications of the SCP model to NASA Pricing Policy issues are presented.

Proposed reliability cost model

Science.gov (United States)

Delionback, L. M.

1973-01-01

The research investigations which were involved in the study include: cost analysis/allocation, reliability and product assurance, forecasting methodology, systems analysis, and model-building. This is a classic example of an interdisciplinary problem, since the model-building requirements include the need for understanding and communication between technical disciplines on one hand, and the financial/accounting skill categories on the other. The systems approach is utilized within this context to establish a clearer and more objective relationship between reliability assurance and the subcategories (or subelements) that provide, or reenforce, the reliability assurance for a system. Subcategories are further subdivided as illustrated by a tree diagram. The reliability assurance elements can be seen to be potential alternative strategies, or approaches, depending on the specific goals/objectives of the trade studies. The scope was limited to the establishment of a proposed reliability cost-model format. The model format/approach is dependent upon the use of a series of subsystem-oriented CER's and sometimes possible CTR's, in devising a suitable cost-effective policy.

Statistical estimation of fast-reactor fuel-element lifetime

International Nuclear Information System (INIS)

Proshkin, A.A.; Likhachev, Yu.I.; Tuzov, A.N.; Zabud'ko, L.M.

1980-01-01

On the basis of a statistical analysis, the main parameters having a significant influence on the theoretical determination of fuel-element lifetimes in the operation of power fast reactors in steady power conditions are isolated. These include the creep and swelling of the fuel and shell materials, prolonged-plasticity lag, shell-material corrosion, gap contact conductivity, and the strain diagrams of the shell and fuel materials obtained for irradiated materials at the corresponding strain rates. By means of deeper investigation of these properties of the materials, it is possible to increase significantly the reliability of fuel-element lifetime predictions in designing fast reactors and to optimize the structure of fuel elements more correctly. The results of such calculations must obviously be taken into account in the cost-benefit analysis of projected new reactors and in choosing the optimal fuel burnup. 9 refs

Animated-simulation modeling facilitates clinical-process costing.

Science.gov (United States)

Zelman, W N; Glick, N D; Blackmore, C C

2001-09-01

Traditionally, the finance department has assumed responsibility for assessing process costs in healthcare organizations. To enhance process-improvement efforts, however, many healthcare providers need to include clinical staff in process cost analysis. Although clinical staff often use electronic spreadsheets to model the cost of specific processes, PC-based animated-simulation tools offer two major advantages over spreadsheets: they allow clinicians to interact more easily with the costing model so that it more closely represents the process being modeled, and they represent cost output as a cost range rather than as a single cost estimate, thereby providing more useful information for decision making.

Rapid calculation of maximum particle lifetime for diffusion in complex geometries

Science.gov (United States)

Carr, Elliot J.; Simpson, Matthew J.

2018-03-01

Diffusion of molecules within biological cells and tissues is strongly influenced by crowding. A key quantity to characterize diffusion is the particle lifetime, which is the time taken for a diffusing particle to exit by hitting an absorbing boundary. Calculating the particle lifetime provides valuable information, for example, by allowing us to compare the timescale of diffusion and the timescale of the reaction, thereby helping us to develop appropriate mathematical models. Previous methods to quantify particle lifetimes focus on the mean particle lifetime. Here, we take a different approach and present a simple method for calculating the maximum particle lifetime. This is the time after which only a small specified proportion of particles in an ensemble remain in the system. Our approach produces accurate estimates of the maximum particle lifetime, whereas the mean particle lifetime always underestimates this value compared with data from stochastic simulations. Furthermore, we find that differences between the mean and maximum particle lifetimes become increasingly important when considering diffusion hindered by obstacles.

Understanding the prevalence of lifetime abstinence from alcohol: An ecological study.

Science.gov (United States)

Probst, Charlotte; Manthey, Jakob; Rehm, Jürgen

2017-09-01

The level of alcohol consumption and related burden in a country are strongly impacted by the prevalence of abstinence from alcohol use. The objective of this study was to characterize the association of lifetime abstinence from alcohol use with economic wealth (as measured in the gross domestic product [GDP]) and Muslim religion on a country level. An ecological study was performed using aggregate data of 183 countries for the year 2010. Lifetime abstinence among men and women was predicted using fractional response regression models with the natural logarithm of GDP-PPP (purchasing power parity) and the proportion of Muslim population as predictors. The models were further adjusted by the country's median age and World Health Organization region. Precision of prediction was investigated. Descriptive analyses showed a strong negative association between GDP-PPP and lifetime abstinence in countries without a Muslim majority and a GDP-PPP up to 20,000 international dollars. Regression models confirmed the negative association with GDP-PPP and showed a strong positive association between lifetime abstinence and the proportion of Muslim population. Stratified sensitivity analyses showed that in countries without a Muslim majority only GDP-PPP showed a statistically significant association whereas in Muslim majority countries only the proportion of Muslims was associated with the prevalence of lifetime abstinence. Particularly in countries with a lower GDP and without Muslim majority the prevalence of lifetime abstinence from alcohol use is strongly negatively associated with GDP-PPP. Future research should analyze the accordance in trends of GDP and lifetime abstinence over time. Copyright © 2017 Elsevier B.V. All rights reserved.

Multiphoton fluorescence lifetime imaging of chemotherapy distribution in solid tumors

Science.gov (United States)

Carlson, Marjorie; Watson, Adrienne L.; Anderson, Leah; Largaespada, David A.; Provenzano, Paolo P.

2017-11-01

Doxorubicin is a commonly used chemotherapeutic employed to treat multiple human cancers, including numerous sarcomas and carcinomas. Furthermore, doxorubicin possesses strong fluorescent properties that make it an ideal reagent for modeling drug delivery by examining its distribution in cells and tissues. However, while doxorubicin fluorescence and lifetime have been imaged in live tissue, its behavior in archival samples that frequently result from drug and treatment studies in human and animal patients, and murine models of human cancer, has to date been largely unexplored. Here, we demonstrate imaging of doxorubicin intensity and lifetimes in archival formalin-fixed paraffin-embedded sections from mouse models of human cancer with multiphoton excitation and multiphoton fluorescence lifetime imaging microscopy (FLIM). Multiphoton excitation imaging reveals robust doxorubicin emission in tissue sections and captures spatial heterogeneity in cells and tissues. However, quantifying the amount of doxorubicin signal in distinct cell compartments, particularly the nucleus, often remains challenging due to strong signals in multiple compartments. The addition of FLIM analysis to display the spatial distribution of excited state lifetimes clearly distinguishes between signals in distinct compartments such as the cell nuclei versus cytoplasm and allows for quantification of doxorubicin signal in each compartment. Furthermore, we observed a shift in lifetime values in the nuclei of transformed cells versus nontransformed cells, suggesting a possible diagnostic role for doxorubicin lifetime imaging to distinguish normal versus transformed cells. Thus, data here demonstrate that multiphoton FLIM is a highly sensitive platform for imaging doxorubicin distribution in normal and diseased archival tissues.

Possibility logic applied to pressure vessel residual lifetime prediction

International Nuclear Information System (INIS)

Garribba, S.; Lucia, A.C.; Volta, G.

1985-01-01

The adequacy is discussed of a probability measure to deal with the different types of uncertainty affecting any pressure vessel lifetime prediction. A more comprehensive framework derived from the fuzzy set theory and including as particular case possibility and probability measures is considered. With reference to the most critical step of lifetime assessment (the ND inspection), the paper compares the results, obtained adopting a possibility measure or a probability measure, in the representation models, fault tree-event tree, and in the decision models

Hot carrier degradation and a new lifetime prediction model in ultra-deep sub-micron pMOSFET

International Nuclear Information System (INIS)

Lei Xiao-Yi; Liu Hong-Xia; Zhang Kai; Zhang Yue; Zheng Xue-Feng; Ma Xiao-Hua; Hao Yue

2013-01-01

The hot carrier effect (HCE) of an ultra-deep sub-micron p-channel metal—oxide semiconductor field-effect transistor (pMOSFET) is investigated in this paper. Experiments indicate that the generation of positively charged interface states is the predominant mechanism in the case of the ultra-deep sub-micron pMOSFET. The relation of the pMOSFET hot carrier degradation to stress time (t), channel width (W), channel length (L), and stress voltage (V d ) is then discussed. Based on the relation, a lifetime prediction model is proposed, which can predict the lifetime of the ultra-deep sub-micron pMOSFET accurately and reflect the influence of the factors on hot carrier degradation directly. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Study of behavior and determination of customer lifetime value(CLV) using Markov chain model

Science.gov (United States)

Permana, Dony; Indratno, Sapto Wahyu; Pasaribu, Udjianna S.

2014-03-01

Customer Lifetime Value or CLV is a restriction on interactive marketing to help a company in arranging financial for the marketing of new customer acquisition and customer retention. Additionally CLV can be able to segment customers for financial arrangements. Stochastic models for the fairly new CLV used a Markov chain. In this model customer retention probability and new customer acquisition probability play an important role. This model is originally introduced by Pfeifer and Carraway in 2000 [1]. They introduced several CLV models, one of them only involves customer and former customer. In this paper we expand the model by adding the assumption of the transition from former customer to customer. In the proposed model, the CLV value is higher than the CLV value obtained by Pfeifer and Caraway model. But our model still requires a longer convergence time.

Study of behavior and determination of customer lifetime value(CLV) using Markov chain model

Energy Technology Data Exchange (ETDEWEB)

Permana, Dony, E-mail: donypermana@students.itb.ac.id [Statistics Research Division, Faculty of Mathematics and Natural Science, Bandung Institute of Technology, Indonesia and Statistics Study Program, Faculty of Mathematics and Natural Sciences, Padang State University (Indonesia); Indratno, Sapto Wahyu; Pasaribu, Udjianna S. [Statistics Research Division, Faculty of Mathematics and Natural Science, Bandung Institute of Technology (Indonesia)

2014-03-24

Customer Lifetime Value or CLV is a restriction on interactive marketing to help a company in arranging financial for the marketing of new customer acquisition and customer retention. Additionally CLV can be able to segment customers for financial arrangements. Stochastic models for the fairly new CLV used a Markov chain. In this model customer retention probability and new customer acquisition probability play an important role. This model is originally introduced by Pfeifer and Carraway in 2000 [1]. They introduced several CLV models, one of them only involves customer and former customer. In this paper we expand the model by adding the assumption of the transition from former customer to customer. In the proposed model, the CLV value is higher than the CLV value obtained by Pfeifer and Caraway model. But our model still requires a longer convergence time.

Study of behavior and determination of customer lifetime value(CLV) using Markov chain model

International Nuclear Information System (INIS)

Permana, Dony; Indratno, Sapto Wahyu; Pasaribu, Udjianna S.

2014-01-01

Customer Lifetime Value or CLV is a restriction on interactive marketing to help a company in arranging financial for the marketing of new customer acquisition and customer retention. Additionally CLV can be able to segment customers for financial arrangements. Stochastic models for the fairly new CLV used a Markov chain. In this model customer retention probability and new customer acquisition probability play an important role. This model is originally introduced by Pfeifer and Carraway in 2000 [1]. They introduced several CLV models, one of them only involves customer and former customer. In this paper we expand the model by adding the assumption of the transition from former customer to customer. In the proposed model, the CLV value is higher than the CLV value obtained by Pfeifer and Caraway model. But our model still requires a longer convergence time

Measurements of heavy quark and lepton lifetimes

International Nuclear Information System (INIS)

Jaros, J.A.

1985-02-01

The PEP/PETRA energy range has proved to be well-suited for the study of the lifetimes of hadrons containing the b and c quarks and the tau lepton for several reasons. First, these states comprise a large fraction of the total interaction rate in e + e - annihilation and can be cleanly identified. Second, the storage rings have operated at high luminosity and so produced these exotic states copiously. And finally, thanks to the interplay of the Fermi coupling strength, the quark and lepton masses, and the beam energy, the expected decay lengths are in the 1/2 mm range and so are comparatively easy to measure. This pleasant coincidence of cleanly identified and abundant signal with potentially large effects has made possible the first measurements of two fundamental weak couplings, tau → nu/sub tau/W and b → cW. These measurements have provided a sharp test of the standard model and allowed, for the first time, the full determination of the magnitudes of the quark mixing matrix. This paper reviews the lifetime studies made at PEP during the past year. It begins with a brief review of the three detectors, DELCO, MAC and MARK II, which have reported lifetime measurements. Next it discusses two new measurements of the tau lifetime, and briefly reviews a measurement of the D 0 lifetime. Finally, it turns to measurements of the B lifetime, which are discussed in some detail. 18 references, 14 figures, 1 table

Cost-effectiveness of aliskiren in type 2 diabetes, hypertension, and albuminuria

DEFF Research Database (Denmark)

Delea, Thomas E; Sofrygin, Oleg; Palmer, James L

2009-01-01

2 diabetes, hypertension, and albuminuria. The cost-effectiveness of this therapy, however, is unknown. Here, we used a Markov model to project progression to ESRD, life years, quality-adjusted life years, and lifetime costs for aliskiren plus losartan versus losartan. We used data from the AVOID...... health care costs increased by $2952, reflecting the higher pharmacy costs of aliskiren and losartan ($7769), which were partially offset by savings in costs of ESRD ($4860). We estimated the cost-effectiveness of aliskiren to be $30,500 per quality-adjusted life year gained. In conclusion, adding...... aliskiren to losartan and optimal therapy in patients with type 2 diabetes, hypertension, and albuminuria may be cost-effective from a US health care system perspective....

Cost-Effectiveness Analysis of the Self-Management Program for Thai Patients with Metabolic Syndrome.

Science.gov (United States)

Sakulsupsiri, Anut; Sakthong, Phantipa; Winit-Watjana, Win

2016-05-01

Lifestyle modification programs are partly evaluated for their usefulness. This study aimed to assess the cost-effectiveness and healthy lifestyle persistence of a self-management program (SMP) for patients with metabolic syndrome (MetS) in Thai health care settings. A cost-effectiveness analysis was performed on the basis of an intervention study of 90 patients with MetS randomly allocated to the SMP and control groups. A Markov model with the Difference-in-Difference method was used to predict the lifetime costs from a societal perspective and quality-adjusted life-years (QALYs), of which 95% confidence intervals (CIs) were estimated by bootstrapping. The cost-effectiveness analysis, along with healthy lifestyle persistence, was performed using the discount rate of 3% per annum. Parameter uncertainties were identified using one-way and probabilistic sensitivity analyses. The lifetime costs tended to decrease in both groups. The SMP could save lifetime costs (-2310 baht; 95% CI -5960 to 1400) and gain QALYs (0.0098; 95% CI -0.0003 to 0.0190), compared with ordinary care. The probability of cost-effectiveness was 99.4% from the Monte-Carlo simulation, and the program was deemed cost-effective at dropout rates below 69% per year as determined by the threshold of 160,000 baht per QALY gained. The cost of macrovascular complications was the most influencing variable for the overall incremental cost-effectiveness ratio. The SMP provided by the health care settings is marginally cost-effective, and the persistence results support the implementation of the program to minimize the complications and economic burden of patients with MetS. Copyright © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Effect of Junction Temperature Swing Durations on a Lifetime of a Transfer Molded IGBT Module

DEFF Research Database (Denmark)

Choi, Uimin; Blaabjerg, Frede; Jorgensen, Soren

2016-01-01

results under 6 different conditions and it may improve a lifetime model for lifetime prediction of IGBT modules under various mission profiles of converters. The power cycling tests are performed by an advanced power cycling test setup which enables tested modules to be operated under more realistic......In this paper, the effect of junction temperature swing duration on the lifetime of a transfer molded Intelligent Power IGBT Module is studied and a relevant lifetime factor is modeled. A temperature swing duration dependent lifetime factor is defined based on 38 accelerated power cycling test...

Assessing long-run economic benefits attributed to an IVF-conceived singleton based on projected lifetime net tax contributions in the UK.

Science.gov (United States)

Connolly, M; Gallo, F; Hoorens, S; Ledger, W

2009-03-01

Over the past decade, demand for fertility treatments has increased as a result of delaying time to first pregnancy and growing awareness and acceptance of available treatment options. Despite increasing demand, health authorities often view infertility as a low health priority and consequently limit access to treatments by rationing and limiting funds. To assess the long-term economic benefits attributed to in vitro fertilization (IVF)-conceived children, we developed a health investment model to evaluate whether state-funded IVF programmes in the UK represent sound fiscal policies. Based on the average investment cost to conceive an IVF singleton, we describe the present value of net taxes derived from gross taxes paid minus direct government transfers received (e.g. education, health, pension) over the lifetime of the child. To establish the present value of investing in IVF, we have discounted all costs from benefits (i.e. lifetime taxes paid) using UK Treasury department rates based on a singleton delivery with similar characteristics for education, earnings, health and life expectancy to a naturally conceived child. The lifetime discounted value of net taxes from an IVF-conceived child with mother aged 35 is pound 109,939 compared with pound 122,127 for a naturally conceived child. The lifetime undiscounted net tax contribution for the IVF-conceived child and naturally conceived child are pound 603,000 and pound 616,000, respectively. An investment of pound 12,931 to achieve an IVF singleton is actually worth 8.5-times this amount to the UK Treasury in discounted future tax revenue. The analysis underscores that costs to the health sector are actually investments when a broader government perspective is considered over a longer period of time.

The increased cost of medical services for people diagnosed with primary open-angle glaucoma: a decision analytic approach.

Science.gov (United States)

Kymes, Steven M; Plotzke, Michael R; Li, Jim Z; Nichol, Michael B; Wu, Joanne; Fain, Joel

2010-07-01

Glaucoma accounts for more than 11% of all cases of blindness in the United States, but there have been few studies of economic impact. We examine incremental cost of primary open-angle glaucoma considering both visual and nonvisual medical costs over a lifetime of glaucoma. A decision analytic approach taking the payor's perspective with microsimulation estimation. We constructed a Markov model to replicate health events over the remaining lifetime of someone newly diagnosed with glaucoma. Costs of this group were compared with those estimated for a control group without glaucoma. The cost of management of glaucoma (including medications) before the onset of visual impairment was not considered. The model was populated with probability data estimated from Medicare claims data (1999 through 2005). Cost of nonocular medications and nursing home use was estimated from California Medicare claims, and all other costs were estimated from Medicare claims data. We found modest differences in the incidence of comorbid conditions and health service use between people with glaucoma and the control group. Over their expected lifetime, the cost of care for people with primary open-angle glaucoma was higher than that of people without primary open-angle glaucoma by $1688 or approximately $137 per year. Among Medicare beneficiaries, glaucoma diagnosis not found to be associated with significant risk of comorbidities before development of visual impairment. Further study is necessary to consider the impact of glaucoma on quality of life, as well as aspects of physical and visual function not captured in this claims-based analysis. 2010 Elsevier Inc. All rights reserved.

Lifetime measurements

International Nuclear Information System (INIS)

Poletti, A.R.

1976-01-01

Recent developments in experimental methods of measuring the lifetimes of excited nuclear states is reviewed in three main areas. (a) Doppler Shift Attenuation Measurements (DSAM) Times: 10 -14 - 10 -11 sec.; (b) Recoil Distance Measurements (RDM) Times: 10 -9 - 10 -12 sec.; (c) Direct Electronic Timing Times: down to 10 -10 sec.; A measurement of an excited state lifetime can answer a large number of different questions. Two examples are discussed: (a) The determination of the lifetime of an isomeric transition in 93 Tc and its use in determining an upper limit for the magnitude of the parity non-conserving matrix element - /Hsub(PN)/17/2 + >. (b) The dependence of the strength of M2 transitions on isospin in nuclei in the 1dsub(3/2) -1fsub(7/2) region. (author)

Ground-Based Telescope Parametric Cost Model

Science.gov (United States)

Stahl, H. Philip; Rowell, Ginger Holmes

2004-01-01

A parametric cost model for ground-based telescopes is developed using multi-variable statistical analysis, The model includes both engineering and performance parameters. While diameter continues to be the dominant cost driver, other significant factors include primary mirror radius of curvature and diffraction limited wavelength. The model includes an explicit factor for primary mirror segmentation and/or duplication (i.e.. multi-telescope phased-array systems). Additionally, single variable models based on aperture diameter are derived. This analysis indicates that recent mirror technology advances have indeed reduced the historical telescope cost curve.

Allocating provider resources to diagnose and treat restless legs syndrome: a cost-utility analysis.

Science.gov (United States)

Padula, William V; Phelps, Charles E; Moran, Dane; Earley, Christopher

2017-10-01

Restless legs syndrome (RLS) is a neurological disorder that is frequently misdiagnosed, resulting in delays in proper treatment. The objective of this study was to analyze the cost-utility of training primary care providers (PCP) in early and accurate diagnosis of RLS. We used a Markov model to compare two strategies: one where PCPs received training to diagnose RLS (informed care) and one where PCPs did not receive training (standard care). This analysis was conducted from the US societal and health sector perspectives over one-year, five-year, and lifetime (50-year) horizons. Costs were adjusted to 2016 USD, utilities measured as quality-adjusted life-years (QALYs), and both measures were discounted annually at 3%. Cost, utilities, and probabilities for the model were obtained through a comprehensive review of literature. An incremental cost-effectiveness ratio (ICER) was calculated to interpret our findings at a willingness-to-pay threshold of $100,000/QALY. Univariate and multivariate analyses were conducted to test model uncertainty, in addition to calculating the expected value of perfect information. Providing training to PCPs to correctly diagnose RLS was cost-effective since it cost $2021 more and gained 0.44 QALYs per patient over the course of a lifetime, resulting in an ICER of $4593/QALY. The model was sensitive to the utility for treated and untreated RLS. The probabilistic sensitivity analysis revealed that at $100,000/QALY, informed care had a 65.5% probability of being cost-effective. A program to train PCPs to better diagnose RLS appears to be a cost-effective strategy for improving outcomes for RLS patients. Copyright © 2017 Elsevier B.V. All rights reserved.

The Impact of a Tax on Sugar-Sweetened Beverages on Health and Health Care Costs: A Modelling Study.

Science.gov (United States)

Veerman, J Lennert; Sacks, Gary; Antonopoulos, Nicole; Martin, Jane

2016-01-01

This paper aims to estimate the consequences of an additional 20% tax on sugar-sweetened beverages (SSBs) on health and health care expenditure. Participants were adult (aged > = 20) Australians alive in 2010, who were modelled over their remaining lifetime. We used lifetable-based epidemiological modelling to examine the potential impact of a 20% valoric tax on SSBs on total lifetime disability-adjusted life years (DALYs), incidence, prevalence, and mortality of obesity-related disease, and health care expenditure. Over the lifetime of adult Australian alive in 2010, seemingly modest estimated changes in average body mass as a result of the SSB tax translated to gains of 112,000 health-adjusted life years for men (95% uncertainty interval [UI]: 73,000-155,000) and 56,000 (95% UI: 36,000-76,000) for women, and a reduction in overall health care expenditure of AUD609 million (95% UI: 368 million- 870 million). The tax is estimated to reduce the number of new type 2 diabetes cases by approximately 800 per year. Twenty-five years after the introduction of the tax, there would be 4,400 fewer prevalent cases of heart disease and 1,100 fewer persons living with the consequences of stroke, and an estimated 1606 extra people would be alive as a result of the tax. The tax would generate an estimated AUD400 million in revenue each year. Governments should consider increasing the tax on sugared drinks. This would improve population health, reduce health care costs, as well as bring in direct revenue.

The Impact of a Tax on Sugar-Sweetened Beverages on Health and Health Care Costs: A Modelling Study.

Directory of Open Access Journals (Sweden)

J Lennert Veerman

Full Text Available This paper aims to estimate the consequences of an additional 20% tax on sugar-sweetened beverages (SSBs on health and health care expenditure. Participants were adult (aged > = 20 Australians alive in 2010, who were modelled over their remaining lifetime. We used lifetable-based epidemiological modelling to examine the potential impact of a 20% valoric tax on SSBs on total lifetime disability-adjusted life years (DALYs, incidence, prevalence, and mortality of obesity-related disease, and health care expenditure. Over the lifetime of adult Australian alive in 2010, seemingly modest estimated changes in average body mass as a result of the SSB tax translated to gains of 112,000 health-adjusted life years for men (95% uncertainty interval [UI]: 73,000-155,000 and 56,000 (95% UI: 36,000-76,000 for women, and a reduction in overall health care expenditure of AUD609 million (95% UI: 368 million- 870 million. The tax is estimated to reduce the number of new type 2 diabetes cases by approximately 800 per year. Twenty-five years after the introduction of the tax, there would be 4,400 fewer prevalent cases of heart disease and 1,100 fewer persons living with the consequences of stroke, and an estimated 1606 extra people would be alive as a result of the tax. The tax would generate an estimated AUD400 million in revenue each year. Governments should consider increasing the tax on sugared drinks. This would improve population health, reduce health care costs, as well as bring in direct revenue.

Modelling the cost-effectiveness of public awareness campaigns for the early detection of non-small-cell lung cancer.

Science.gov (United States)

Hinde, S; McKenna, C; Whyte, S; Peake, M D; Callister, M E J; Rogers, T; Sculpher, M

2015-06-30

Survival rates in lung cancer in England are significantly lower than in many similar countries. A range of Be Clear on Cancer (BCOC) campaigns have been conducted targeting lung cancer and found to improve the proportion of diagnoses at the early stage of disease. This paper considers the cost-effectiveness of such campaigns, evaluating the effect of both the regional and national BCOC campaigns on the stage distribution of non-small-cell lung cancer (NSCLC) at diagnosis. A natural history model of NSCLC was developed using incidence data, data elicited from clinical experts and model calibration techniques. This structure is used to consider the lifetime cost and quality-adjusted survival implications of the early awareness campaigns. Incremental cost-effectiveness ratios (ICERs) in terms of additional costs per quality-adjusted life-years (QALYs) gained are presented. Two scenario analyses were conducted to investigate the role of changes in the 'worried-well' population and the route of diagnosis that might occur as a result of the campaigns. The base-case theoretical model found the regional and national early awareness campaigns to be associated with QALY gains of 289 and 178 QALYs and ICERs of £13 660 and £18 173 per QALY gained, respectively. The scenarios found that increases in the 'worried-well' population may impact the cost-effectiveness conclusions. Subject to the available evidence, the analysis suggests that early awareness campaigns in lung cancer have the potential to be cost-effective. However, significant additional research is required to address many of the limitations of this study. In addition, the estimated natural history model presents previously unavailable estimates of the prevalence and rate of disease progression in the undiagnosed population.

Healthcare costs attributable to the treatment of patients with spinal metastases

DEFF Research Database (Denmark)

Tipsmark, Line Stjernholm; Bünger, Cody Eric; Wang, Miao

2015-01-01

for 65% and outpatient services for 31% of the healthcare costs followed by hospice placements 3% and primary care 1%. Lifetime healthcare costs accounted for €36,616 (95% CI 33,835-39,583) per T1 patients, €49,632 (95% CI 42,287-57,767) per T2 patient, €70997 (95% CI 62,244-82,354) per T3 patient...... with an average of 71% for inpatient hospitalisation and 25% for outpatient services. CONCLUSION: The index treatment accounts for almost half of lifetime health care costs from treatment initiation until death. As expected, lifetime healthcare costs are positively association with invasiveness of treatment.......BACKGROUND: Cancer treatment, and in particular end-of-life treatment, is associated with substantial healthcare costs. The purpose of this study was to analyse healthcare costs attributable to the treatment of patients with spinal metastases. METHODS: The study population (n = 629) was identified...

Clinical effectiveness and cost-effectiveness of second- and third-generation left ventricular assist devices as either bridge to transplant or alternative to transplant for adults eligible for heart transplantation: systematic review and cost-effectiveness model.

Science.gov (United States)

Sutcliffe, P; Connock, M; Pulikottil-Jacob, R; Kandala, N-B; Suri, G; Gurung, T; Grove, A; Shyangdan, D; Briscoe, S; Maheswaran, H; Clarke, A

2013-11-01

-effectiveness of second- and third-generation US Food and Drug Administration (FDA) and/or Conformité Européenne (CE) approved VADs. Publications from the last 5 years with control groups, or case series with 50 or more patients were included. Outcomes included survival, functional capacity (e.g. change in New York Heart Association functional classification), quality of life (QoL) and adverse events. Data from the BTDB were obtained. A discrete-time, semi-Markov, multistate model was built. Deterministic and probabilistic methods with multiple sensitivity analyses varying survival, utilities and cost inputs to the model were used. Model outputs were incremental cost-effectiveness ratios (ICERs), cost/quality-adjusted life-years (QALYs) gained and cost/life-year gained (LYG). The discount rate was 3.5% and the time horizon varied over 3 years, 10 years and lifetime. Forty publications reported clinical effectiveness of VADs and one study reported cost-effectiveness. We found no high-quality comparative empirical studies of VADs as BTT compared with MM or as ATT compared with BTT. Approximately 15-25% of the patients receiving a device had died by 12 months. Studies reported the following wide ranges for adverse events: 4-27% bleeding requiring transfusion; 1.5-40% stroke; 3.3-48% infection; 1-14% device failure; 3-30% HF; 11-32% reoperation; and 3-53% renal failure. QoL and functional status were reported as improved in studies of two devices [HeartMate II (HMII; Thoratec Inc., Pleasanton, CA, USA) and HeartWare (HW; HeartWare Inc., Framingham, MA, USA)]. At 3 years, 10 years and lifetime, the ICERs for VADs as BTT compared with MM were £122,730, £68,088 and £55,173 respectively. These values were stable to changes in survival of the MM group. Both QoL and costs were reduced by VADs as ATT compared with VADs as BTT giving ICERs in south-west quadrant of the cost effectiveness plain (cost saving/QALY sacrificed) of £353,467, £31,685 and £20,637 over the 3 years, 10 years

Distribution Grid Integration Unit Cost Database | Solar Research | NREL

Science.gov (United States)

consulting companies, IEEE Some data is provided to give a sense of the order of magnitude of the lifetime , as O&M and component lifetime data is sparse, the effects of PV on device O&M and lifetimes Inverter manufacturers, PV developers The cost of advanced inverters depends on whether the capability of

SUPPLIES COSTS: AN EXPLORATORY STUDY WITH APPLICATION OF MEASUREMENT MODEL OF LOGISTICS COSTS

Directory of Open Access Journals (Sweden)

Ana Paula Ferreira Alves

2013-12-01

Full Text Available One of the main reasons for the difficulty in adopting an integrated method of calculation of logistics costs is still a lack of adequate information about costs. The management of the supply chain and identify its costs can provide information for their managers, with regard to decision making, generating competitive advantage. Some models of calculating logistics costs are proposed by Uelze (1974, Dias (1996, Goldratt (2002, Christopher (2007, Castiglioni (2009 and Borba & Gibbon (2009, with little disclosure of the results. In this context, this study aims to evaluate the costs of supplies, applying a measurement model of logistics costs. Methodologically, the study characterized as exploratory. The model applied pointed, in original condition, that about R$ 2.5 million were being applied in the process of management of supplies, with replacement costs and storage imbalance. Upgrading the company's data, it is possible obtain a 52% reduction in costs to replace and store supplies. Thus, the cost model applied to logistical supplies showed feasibility of implementation, as well as providing information to assist in management and decision-making in logistics supply.

Positron lifetime spectroscopy of internally oxidised Ag-In alloys

International Nuclear Information System (INIS)

Wegner, D.; Lieb, K.P.

1989-01-01

The effects of In 2 O 3 precipitates on positron lifetimes after internal oxidation of α-Ag-In alloys have been investigated. A positron trap associated with the lifetime τ 205(3) ps was detected. On the basis of the experimental results obtained for different oxidation kinetics parameters, a trapping model is proposed according to which positrons thermalised in a dislocation field around oxide precipitates are trapped at the oxide/metal phase boundary. The transition from internal to external oxidation of Ag-In was also studied. The positron lifetime in In 2 O 3 was measured to be τ = 263(8) ps. (author)

Lifetime health effects and costs of diabetes treatment

NARCIS (Netherlands)

L.W. Niessen (Louis Wilhelmus); R. Dijkstra; R.C.W. Hutubessy (Raymond); G.E.H.M. Rutten (Guy); A.F. Casparie (Anton)

2003-01-01

textabstractBACKGROUND: This article presents cost-effectiveness analyses of the major diabetes interventions as formulated in the revised Dutch guidelines for diabetes type 2 patients in primary and secondary care. The analyses consider two types of care: diabetes control and the

Quantum system lifetimes and measurement perturbations

International Nuclear Information System (INIS)

Najakov, E.

1977-05-01

The recently proposed description of quantum system decay in terms of repeated measurement perturbations is modified. The possibility of retarded reductions to a unique quantum state, due to ineffective localization of the decay products at initial time measurements, is simply taken into account. The exponential decay law is verified again. A modified equation giving the observed lifetime in terms of unperturbed quantum decay law, measurement frequency and reduction law is derived. It predicts deviations of the observed lifetime from the umperturbed one, together with a dependence on experimental procedures. The influence of different model unperturbed decay laws and reduction laws on this effect is studied

Lifetimes of heavy flavour particles

International Nuclear Information System (INIS)

Forty, R.

1994-01-01

The lifetimes of heavy-flavour hadrons are reviewed. After a brief discussion of the theoretical predictions, the problem of averaging lifetime measurements is discussed. The various experimental measurements are then presented and suitable averages performed. Charmed meson lifetimes are now measured to the few percent level, better that theory can predict, whilst for charmed baryons the lifetime hierarchy has been established for the first time. For beauty hadrons the lifetimes are measured at the 6-10 % level, and are in reasonable agreement with theoretical expectations. Beauty baryon studies ar just beginning. (author)

Operating cost model for local service airlines

Science.gov (United States)

Anderson, J. L.; Andrastek, D. A.

1976-01-01

Several mathematical models now exist which determine the operating economics for a United States trunk airline. These models are valuable in assessing the impact of new aircraft into an airline's fleet. The use of a trunk airline cost model for the local service airline does not result in representative operating costs. A new model is presented which is representative of the operating conditions and resultant costs for the local service airline. The calculated annual direct and indirect operating costs for two multiequipment airlines are compared with their actual operating experience.

Extending the Lifetime of Sensor Networks through Adaptive Reclustering

Directory of Open Access Journals (Sweden)

Gianluigi Ferrari

2007-06-01

Full Text Available We analyze the lifetime of clustered sensor networks with decentralized binary detection under a physical layer quality-of-service (QoS constraint, given by the maximum tolerable probability of decision error at the access point (AP. In order to properly model the network behavior, we consider four different distributions (exponential, uniform, Rayleigh, and lognormal for the lifetime of a single sensor. We show the benefits, in terms of longer network lifetime, of adaptive reclustering. We also derive an analytical framework for the computation of the network lifetime and the penalty, in terms of time delay and energy consumption, brought by adaptive reclustering. On the other hand, absence of reclustering leads to a shorter network lifetime, and we show the impact of various clustering configurations under different QoS conditions. Our results show that the organization of sensors in a few big clusters is the winning strategy to maximize the network lifetime. Moreover, the observation of the phenomenon should be frequent in order to limit the penalties associated with the reclustering procedure. We also apply the developed framework to analyze the energy consumption associated with the proposed reclustering protocol, obtaining results in good agreement with the performance of realistic wireless sensor networks. Finally, we present simulation results on the lifetime of IEEE 802.15.4 wireless sensor networks, which enrich the proposed analytical framework and show that typical networking performance metrics (such as throughput and delay are influenced by the sensor network lifetime.

Extending the Lifetime of Sensor Networks through Adaptive Reclustering

Directory of Open Access Journals (Sweden)

Ferrari Gianluigi

2007-01-01

Full Text Available We analyze the lifetime of clustered sensor networks with decentralized binary detection under a physical layer quality-of-service (QoS constraint, given by the maximum tolerable probability of decision error at the access point (AP. In order to properly model the network behavior, we consider four different distributions (exponential, uniform, Rayleigh, and lognormal for the lifetime of a single sensor. We show the benefits, in terms of longer network lifetime, of adaptive reclustering. We also derive an analytical framework for the computation of the network lifetime and the penalty, in terms of time delay and energy consumption, brought by adaptive reclustering. On the other hand, absence of reclustering leads to a shorter network lifetime, and we show the impact of various clustering configurations under different QoS conditions. Our results show that the organization of sensors in a few big clusters is the winning strategy to maximize the network lifetime. Moreover, the observation of the phenomenon should be frequent in order to limit the penalties associated with the reclustering procedure. We also apply the developed framework to analyze the energy consumption associated with the proposed reclustering protocol, obtaining results in good agreement with the performance of realistic wireless sensor networks. Finally, we present simulation results on the lifetime of IEEE 802.15.4 wireless sensor networks, which enrich the proposed analytical framework and show that typical networking performance metrics (such as throughput and delay are influenced by the sensor network lifetime.

Genotypic-specific variance in Caenorhabditis elegans lifetime fecundity.

Science.gov (United States)

Diaz, S Anaid; Viney, Mark

2014-06-01

Organisms live in heterogeneous environments, so strategies that maximze fitness in such environments will evolve. Variation in traits is important because it is the raw material on which natural selection acts during evolution. Phenotypic variation is usually thought to be due to genetic variation and/or environmentally induced effects. Therefore, genetically identical individuals in a constant environment should have invariant traits. Clearly, genetically identical individuals do differ phenotypically, usually thought to be due to stochastic processes. It is now becoming clear, especially from studies of unicellular species, that phenotypic variance among genetically identical individuals in a constant environment can be genetically controlled and that therefore, in principle, this can be subject to selection. However, there has been little investigation of these phenomena in multicellular species. Here, we have studied the mean lifetime fecundity (thus a trait likely to be relevant to reproductive success), and variance in lifetime fecundity, in recently-wild isolates of the model nematode Caenorhabditis elegans. We found that these genotypes differed in their variance in lifetime fecundity: some had high variance in fecundity, others very low variance. We find that this variance in lifetime fecundity was negatively related to the mean lifetime fecundity of the lines, and that the variance of the lines was positively correlated between environments. We suggest that the variance in lifetime fecundity may be a bet-hedging strategy used by this species.

Positron lifetime studies of electron irradiated copper

International Nuclear Information System (INIS)

Hadnagy, T.D.

1976-01-01

Single-crystal copper was irradiated with 4.5-MeV electrons producing simple Frenkel defects as well as a significant concentration of divacancies. Mean positron lifetime characteristics, which are sensitive to the presence of vacancies and multivacancies in copper, was monitored after isochronal anneals between 80 and 800 0 K to determine the relative change of characteristic mean lifetimes and their associated intensities. Also a study of the dependence of the mean positron lifetime on the total electron fluence was made and compared with existing theories relating these lifetimes to vacancy or multivacancy concentrations. Numerical data from curve fitting procedures using a conventional trapping model for defect-induced changes in positron lifetimes indicate that upon irradiation with 4.5-MeV electrons at 80 0 K, about 8 percent of the defects produced are divacancy units. Divacancy units appear to be several times more effective in trapping positrons than are monovacancies. Further, the experimental data suggest that the stage III annealing processes in electron-irradiated copper most probably involve the motion and removal of both monovacancies and divacancies. A conglomerate (multivacancy) unit appears to exist as a stable entity even after annealing procedures are carried out at temperatures slightly above the stage III region. Such a stable unit could serve as a nucleation center for the appearance of voids

Process Cost Modeling for Multi-Disciplinary Design Optimization

Science.gov (United States)

Bao, Han P.; Freeman, William (Technical Monitor)

2002-01-01

For early design concepts, the conventional approach to cost is normally some kind of parametric weight-based cost model. There is now ample evidence that this approach can be misleading and inaccurate. By the nature of its development, a parametric cost model requires historical data and is valid only if the new design is analogous to those for which the model was derived. Advanced aerospace vehicles have no historical production data and are nowhere near the vehicles of the past. Using an existing weight-based cost model would only lead to errors and distortions of the true production cost. This report outlines the development of a process-based cost model in which the physical elements of the vehicle are costed according to a first-order dynamics model. This theoretical cost model, first advocated by early work at MIT, has been expanded to cover the basic structures of an advanced aerospace vehicle. Elemental costs based on the geometry of the design can be summed up to provide an overall estimation of the total production cost for a design configuration. This capability to directly link any design configuration to realistic cost estimation is a key requirement for high payoff MDO problems. Another important consideration in this report is the handling of part or product complexity. Here the concept of cost modulus is introduced to take into account variability due to different materials, sizes, shapes, precision of fabrication, and equipment requirements. The most important implication of the development of the proposed process-based cost model is that different design configurations can now be quickly related to their cost estimates in a seamless calculation process easily implemented on any spreadsheet tool. In successive sections, the report addresses the issues of cost modeling as follows. First, an introduction is presented to provide the background for the research work. Next, a quick review of cost estimation techniques is made with the intention to

A cost-effectiveness analysis of long-term intermittent catheterisation with hydrophilic and uncoated catheters

DEFF Research Database (Denmark)

Clark, J F; Mealing, S J; Scott, D A

2016-01-01

includes the long-term sequelae of impaired renal function and urinary tract infection (UTI). SETTING: Analysis based on a UK perspective. METHODS: A probabilistic Markov decision model was constructed, to compare lifetime costs and quality-adjusted life years, taking renal and UTI health states...... into consideration, as well as other catheter-related events. UTI event rates for the primary data set were based on data from hospital settings to ensure controlled and accurate reporting. A sensitivity analysis was applied to evaluate best- and worst-case scenarios. RESULTS: The model predicts that a 36-year......-old SCI patient with chronic urinary retention will live an additional 1.4 years if using HC catheters compared with UC catheters, at an incremental cost of £2100. Moreover, the lifetime number of UTI events will be reduced by 16%. All best- and worst-case estimates were within the UK threshold of being...

Preliminary Multi-Variable Cost Model for Space Telescopes

Science.gov (United States)

Stahl, H. Philip; Hendrichs, Todd

2010-01-01

Parametric cost models are routinely used to plan missions, compare concepts and justify technology investments. This paper reviews the methodology used to develop space telescope cost models; summarizes recently published single variable models; and presents preliminary results for two and three variable cost models. Some of the findings are that increasing mass reduces cost; it costs less per square meter of collecting aperture to build a large telescope than a small telescope; and technology development as a function of time reduces cost at the rate of 50% per 17 years.

A model for predicting the lifetimes of Grade-2 titanium nuclear waste containers

International Nuclear Information System (INIS)

Shoesmith, D.W.; Ikeda, B.M.; Bailey, M.G.; Quinn, M.J.; LeNeveu, D.M.

1995-08-01

The development of a model to predict the lifetimes of Grade-2 titanium containers for nuclear fuel waste is described. This model assumes that the corrosion processes most likely to lead to container failure are crevice corrosion, hydrogen-induced cracking and general corrosion. Because of the expected evolution of waste vault conditions from initially warm (<∼ 100 deg C) and oxidizing to eventually cool (<30 deg C) and non-oxiding, the period for which crevice corrosion can propagate will be limited by repassivation, and long container lifetimes will be achieved since the rate of general corrosion is extremely low. However, in the model presented, not only is it assumed that crevices will initiate rapidly on all containers, but also that the propagation of these crevices will continue indefinitely since conditions will remain sufficiently oxiding for repassivation to be avoided. The mathematical development of the model is described in detail. A simple ramped distribution is used to describe the failures due to the presence of initial defects. For crevice corrosion the propagation rates are assumed to be normally distributed and to be determined predominantly by temperature. The temperature dependence of the crevice propagation rate is determined from the calculated cooling profiles for the containers and an experimentally determined Arrhenius relationship for crevice propagation rates. The cooling profiles are approximated by double or single step functions, depending on the location of the container within the vault. The experimental data upon which this model is based is extensively reviewed. This review includes descriptions of the available data to describe and quantify the processes of general corrosion, crevice corrosion and hydrogen-induced cracking. For crevice corrosion and hydrogen-induced cracking the results of studies on both Grades-2 and -12 are presented. Also, the effects of impurities in the Grade-2 material are discussed. Special attention is

Monte Carlo mixture model of lifetime cancer incidence risk from radiation exposure on shuttle and international space station

International Nuclear Information System (INIS)

Peterson, L.E.; Cucinotta, F.A.

1999-01-01

Estimating uncertainty in lifetime cancer risk for human exposure to space radiation is a unique challenge. Conventional risk assessment with low-linear-energy-transfer (LET)-based risk from Japanese atomic bomb survivor studies may be inappropriate for relativistic protons and nuclei in space due to track structure effects. This paper develops a Monte Carlo mixture model (MCMM) for transferring additive, National Institutes of Health multiplicative, and multiplicative excess cancer incidence risks based on Japanese atomic bomb survivor data to determine excess incidence risk for various US astronaut exposure profiles. The MCMM serves as an anchor point for future risk projection methods involving biophysical models of DNA damage from space radiation. Lifetime incidence risks of radiation-induced cancer for the MCMM based on low-LET Japanese data for nonleukemia (all cancers except leukemia) were 2.77 (90% confidence limit, 0.75-11.34) for males exposed to 1 Sv at age 45 and 2.20 (90% confidence limit, 0.59-10.12) for males exposed at age 55. For females, mixture model risks for nonleukemia exposed separately to 1 Sv at ages of 45 and 55 were 2.98 (90% confidence limit, 0.90-11.70) and 2.44 (90% confidence limit, 0.70-10.30), respectively. Risks for high-LET 200 MeV protons (LET=0.45 keV/μm), 1 MeV α-particles (LET=100 keV/μm), and 600 MeV iron particles (LET=180 keV/μm) were scored on a per particle basis by determining the particle fluence required for an average of one particle per cell nucleus of area 100 μm 2 . Lifetime risk per proton was 2.68x10 -2 % (90% confidence limit, 0.79x10 -3 %-0.514x10 -2 %). For α-particles, lifetime risk was 14.2% (90% confidence limit, 2.5%-31.2%). Conversely, lifetime risk per iron particle was 23.7% (90% confidence limit, 4.5%-53.0%). Uncertainty in the DDREF for high-LET particles may be less than that for low-LET radiation because typically there is very little dose-rate dependence. Probability density functions for

Modeling Operations Costs for Human Exploration Architectures

Science.gov (United States)

Shishko, Robert

2013-01-01

Operations and support (O&S) costs for human spaceflight have not received the same attention in the cost estimating community as have development costs. This is unfortunate as O&S costs typically comprise a majority of life-cycle costs (LCC) in such programs as the International Space Station (ISS) and the now-cancelled Constellation Program. Recognizing this, the Constellation Program and NASA HQs supported the development of an O&S cost model specifically for human spaceflight. This model, known as the Exploration Architectures Operations Cost Model (ExAOCM), provided the operations cost estimates for a variety of alternative human missions to the moon, Mars, and Near-Earth Objects (NEOs) in architectural studies. ExAOCM is philosophically based on the DoD Architecture Framework (DoDAF) concepts of operational nodes, systems, operational functions, and milestones. This paper presents some of the historical background surrounding the development of the model, and discusses the underlying structure, its unusual user interface, and lastly, previous examples of its use in the aforementioned architectural studies.

Impacts of PV Array Sizing on PV Inverter Lifetime and Reliability

OpenAIRE

Sangwongwanich, Ariya; Yang, Yongheng; Sera, Dezso; Blaabjerg, Frede

2017-01-01

In order to enable a more wide-scale utilization of PV systems, the cost of PV energy has to be comparable with other energy sources. Oversizing the PV array is one common approach to reduce the cost of PV energy, since it increases the PV energy yield during low solar irradiance conditions. However, oversizing the PV array will increase the loading of PV inverters, which may have undesired influence on the PV inverter lifetime and reliability. In that case, it may result in a negative impact...

Study on Effect of Junction Temperature Swing Duration on Lifetime of Transfer Molded Power IGBT Modules

DEFF Research Database (Denmark)

Choi, Uimin; Blaabjerg, Frede; Jørgensen, Søren

2017-01-01

levels are presented. This study enables to include the tΔTj effect on lifetime model of IGBT modules for its lifetime estimation and it may result in improved lifetime prediction of IGBT modules under given mission profiles of converters. A postfailure analysis of the tested IGBT modules is also......In this paper, the effect of junction temperature swing duration on lifetime of transfer molded power insulated gate bipolar transistor (IGBT) modules is studied and a relevant lifetime factor is modeled. This study is based on 39 accelerated power cycling test results under six different...

Predicting a future lifetime through Box-Cox transformation.

Science.gov (United States)

Yang, Z

1999-09-01

In predicting a future lifetime based on a sample of past lifetimes, the Box-Cox transformation method provides a simple and unified procedure that is shown in this article to meet or often outperform the corresponding frequentist solution in terms of coverage probability and average length of prediction intervals. Kullback-Leibler information and second-order asymptotic expansion are used to justify the Box-Cox procedure. Extensive Monte Carlo simulations are also performed to evaluate the small sample behavior of the procedure. Certain popular lifetime distributions, such as Weibull, inverse Gaussian and Birnbaum-Saunders are served as illustrative examples. One important advantage of the Box-Cox procedure lies in its easy extension to linear model predictions where the exact frequentist solutions are often not available.

Validation of the OpCost logging cost model using contractor surveys

Science.gov (United States)

Conor K. Bell; Robert F. Keefe; Jeremy S. Fried

2017-01-01

OpCost is a harvest and fuel treatment operations cost model developed to function as both a standalone tool and an integrated component of the Bioregional Inventory Originated Simulation Under Management (BioSum) analytical framework for landscape-level analysis of forest management alternatives. OpCost is an updated implementation of the Fuel Reduction Cost Simulator...

Medical therapy v. PCI in stable coronary artery disease: a cost-effectiveness analysis.

Science.gov (United States)

Wijeysundera, Harindra C; Tomlinson, George; Ko, Dennis T; Dzavik, Vladimir; Krahn, Murray D

2013-10-01

Percutaneous coronary intervention (PCI) with either drug-eluting stents (DES) or bare metal stents (BMS) reduces angina and repeat procedures compared with optimal medical therapy alone. It remains unclear if these benefits are sufficient to offset their increased costs and small increase in adverse events. Cost utility analysis of initial medical therapy v. PCI with either BMS or DES. . Markov cohort decision model. Data Sources. Propensity-matched observational data from Ontario, Canada, for baseline event rates. Effectiveness and utility data obtained from the published literature, with costs from the Ontario Case Costing Initiative. Patients with stable coronary artery disease, confirmed after angiography, stratified by risk of restenosis based on diabetic status, lesion size, and lesion length. Time Horizon. Lifetime. Perspective. Ontario Ministry of Health and Long Term Care. Interventions. Optimal medical therapy, PCI with BMS or DES. Lifetime costs, quality-adjusted life years (QALYs), and the incremental cost-effectiveness ratio (ICER). of Base Case Analysis. In the overall population, medical therapy had the lowest lifetime costs at $22,952 v. $25,081 and $25,536 for BMS and DES, respectively. Medical therapy had a quality-adjusted life expectancy of 10.1 v. 10.26 QALYs for BMS, producing an ICER of $13,271/QALY. The DES strategy had a quality-adjusted life expectancy of only 10.20 QALYs and was dominated by the BMS strategy. This ranking was consistent in all groups stratified by restenosis risk, except diabetic patients with long lesions in small arteries, in whom DES was cost-effective compared with medical therapy (ICER of $18,826/QALY). Limitations. There is the possibility of residual unobserved confounding. In patients with stable coronary artery disease, an initial BMS strategy is cost-effective.

NASA Software Cost Estimation Model: An Analogy Based Estimation Model

Science.gov (United States)

Hihn, Jairus; Juster, Leora; Menzies, Tim; Mathew, George; Johnson, James

2015-01-01

The cost estimation of software development activities is increasingly critical for large scale integrated projects such as those at DOD and NASA especially as the software systems become larger and more complex. As an example MSL (Mars Scientific Laboratory) developed at the Jet Propulsion Laboratory launched with over 2 million lines of code making it the largest robotic spacecraft ever flown (Based on the size of the software). Software development activities are also notorious for their cost growth, with NASA flight software averaging over 50% cost growth. All across the agency, estimators and analysts are increasingly being tasked to develop reliable cost estimates in support of program planning and execution. While there has been extensive work on improving parametric methods there is very little focus on the use of models based on analogy and clustering algorithms. In this paper we summarize our findings on effort/cost model estimation and model development based on ten years of software effort estimation research using data mining and machine learning methods to develop estimation models based on analogy and clustering. The NASA Software Cost Model performance is evaluated by comparing it to COCOMO II, linear regression, and K-­ nearest neighbor prediction model performance on the same data set.

Spatial mapping of exciton lifetimes in single ZnO nanowires

Directory of Open Access Journals (Sweden)

J. S. Reparaz

2013-07-01

Full Text Available We investigate the spatial dependence of the exciton lifetimes in single ZnO nanowires. We have found that the free exciton and bound exciton lifetimes exhibit a maximum at the center of nanowires, while they decrease by 30% towards the tips. This dependence is explained by considering the cavity-like properties of the nanowires in combination with the Purcell effect. We show that the lifetime of the bound-excitons scales with the localization energy to the power of 3/2, which validates the model of Rashba and Gurgenishvili at the nanoscale.

Positron lifetime calculation for defects and defect clusters in graphite

International Nuclear Information System (INIS)

Onitsuka, T.; Ohkubo, H.; Takenaka, M.; Tsukuda, N.; Kuramoto, E.

2000-01-01

Calculations of positron lifetime have been made for vacancy type defects in graphite and compared with experimental results. Defect structures were obtained in a model graphite lattice after including relaxation of whole lattice as determined by the molecular dynamics method, where the interatomic potential given by Pablo Andribet, Dominguez-Vazguez, Mari Carmen Perez-Martin, Alonso, Jimenez-Rodriguez [Nucl. Instrum. and Meth. 115 (1996) 501] was used. For the defect structures obtained via lattice relaxation positron lifetime was calculated under the so-called atomic superposition method. Positron lifetimes 204 and 222 ps were obtained for the graphite matrix and a single vacancy, respectively, which can be compared with the experimental results 208 and 233 ps. For planar vacancy clusters, e.g., vacancy loops, lifetime calculation was also made and indicated that lifetime increases with the number of vacancies in a cluster. This is consistent with the experimental result in the region of higher annealing temperature (above 1200 deg. C), where the increase of positron lifetime is seen, probably corresponding to the clustering of mobile vacancies

Integrated modeling of software cost and quality

International Nuclear Information System (INIS)

Rone, K.Y.; Olson, K.M.

1994-01-01

In modeling the cost and quality of software systems, the relationship between cost and quality must be considered. This explicit relationship is dictated by the criticality of the software being developed. The balance between cost and quality is a viable software engineering trade-off throughout the life cycle. Therefore, the ability to accurately estimate the cost and quality of software systems is essential to providing reliable software on time and within budget. Software cost models relate the product error rate to the percent of the project labor that is required for independent verification and validation. The criticality of the software determines which cost model is used to estimate the labor required to develop the software. Software quality models yield an expected error discovery rate based on the software size, criticality, software development environment, and the level of competence of the project and the developers with respect to the processes being employed

Lifetime of heavy hypernuclei and its implications on the weak LAMBDA N interaction

CERN Document Server

Cassing, W; Kamys, B; Kulessa, P; Niewodniczanski, H; Ohm, H; Pysz, K; Rudy, Z; Schult, O W B; Ströher, H

2003-01-01

The lifetime of the LAMBDA-hyperon in heavy hypernuclei measured in proton-Au, -Bi and -U collisions by the COSY-13 Collaboration at COSY-Juelich has been analyzed to yield tau subLAMBDA=(145+-11) ps. This value for tau subLAMBDA is compatible with the lifetime extracted from antiproton annihilation on Bi and U targets, albeit much more accurate. Theoretical models based on the meson exchange picture and assuming the validity of the phenomenological DELTA I=1/2 rule predict the lifetime of heavy hypernuclei to be significantly larger (2-3 standard deviations). Such large differences indicate that at least one of the assumptions in these models is not fulfilled. A much better reproduction of the lifetimes of heavy hypernuclei is achieved in the phase space model, if the DELTA I=1/2 rule is discarded in the nonmesonic LAMBDA decay. (orig.)

Lifetime of heavy hypernuclei and its implications on the weak ΛN interaction

International Nuclear Information System (INIS)

Cassing, W.; Jarczyk, L.; Kamys, B.; Kulessa, P.; Pysz, K.; Ohm, H.; Schult, O.W.B.; Stroeher, H.; Rudy, Z.

2003-01-01

The lifetime of the Λ-hyperon in heavy hypernuclei measured in proton-Au, -Bi and -U collisions by the COSY-13 Collaboration at COSY-Juelich has been analyzed to yield τ Λ =(145±11) ps. This value for τ Λ is compatible with the lifetime extracted from antiproton annihilation on Bi and U targets, albeit much more accurate. Theoretical models based on the meson exchange picture and assuming the validity of the phenomenological ΔI=1/2 rule predict the lifetime of heavy hypernuclei to be significantly larger (2-3 standard deviations). Such large differences indicate that at least one of the assumptions in these models is not fulfilled. A much better reproduction of the lifetimes of heavy hypernuclei is achieved in the phase space model, if the ΔI=1/2 rule is discarded in the nonmesonic Λ decay. (orig.)

Three-dimensional fluorescence lifetime tomography

International Nuclear Information System (INIS)

Godavarty, Anuradha; Sevick-Muraca, Eva M.; Eppstein, Margaret J.

2005-01-01

Near-infrared fluorescence tomography using molecularly targeted lifetime-sensitive, fluorescent contrast agents have applications for early-stage cancer diagnostics. Yet, although the measurement of fluorescent lifetime imaging microscopy (FLIM) is extensively used in microscopy and spectroscopy applications, demonstration of fluorescence lifetime tomography for medical imaging is limited to two-dimensional studies. Herein, the feasibility of three-dimensional fluorescence-lifetime tomography on clinically relevant phantom volumes is established, using (i) a gain-modulated intensified charge coupled device (CCD) and modulated laser diode imaging system, (ii) two fluorescent contrast agents, e.g., Indocyanine green and 3-3'-Diethylthiatricarbocyanine iodide differing in their fluorescence lifetime by 0.62 ns, and (iii) a two stage approximate extended Kalman filter reconstruction algorithm. Fluorescence measurements of phase and amplitude were acquired on the phantom surface under different target to background fluorescence absorption (70:1, 100:1) and fluorescence lifetime (1:1, 2.1:1) contrasts at target depths of 1.4-2 cm. The Bayesian tomography algorithm was employed to obtain three-dimensional images of lifetime and absorption owing to the fluorophores

System, economy and ecology viewpoints of the Krsko NPP lifetime extension

International Nuclear Information System (INIS)

Novsak, M.; Spiler, J.; Zagar, T.; Pirs, B.; Bole, A.; Bregar, Z.; Cuhalev, I.; Derganc, B.; Ivanjko, S.; Matvoz, D.; Sustersic, A.; Valencic, L.; Zabric, I.; Zlatarev, G.; Babuder, M.

2007-01-01

Krsko NPP plant life extension was analysed and evaluated with respect to system, economy and ecology viewpoints. From the system perspective it was established that also in the extended lifetime the plant will remain in operation as a base load electricity supplier. The systematic review was performed to determine its overall competitiveness against advanced coal, gas and new nuclear units. The analysis considered also hydro and renewable sources. Analysis and evaluations resulted in the conclusion that the Krsko NPP lifetime extension is the most effective alternative for base load production due to small additional capital investments, low fuel costs, no new siting requirements, lowest climate and environmental impact, and reliable and safe operation. (author)

Oil and gas pipeline construction cost analysis and developing regression models for cost estimation

Science.gov (United States)

Thaduri, Ravi Kiran

In this study, cost data for 180 pipelines and 136 compressor stations have been analyzed. On the basis of the distribution analysis, regression models have been developed. Material, Labor, ROW and miscellaneous costs make up the total cost of a pipeline construction. The pipelines are analyzed based on different pipeline lengths, diameter, location, pipeline volume and year of completion. In a pipeline construction, labor costs dominate the total costs with a share of about 40%. Multiple non-linear regression models are developed to estimate the component costs of pipelines for various cross-sectional areas, lengths and locations. The Compressor stations are analyzed based on the capacity, year of completion and location. Unlike the pipeline costs, material costs dominate the total costs in the construction of compressor station, with an average share of about 50.6%. Land costs have very little influence on the total costs. Similar regression models are developed to estimate the component costs of compressor station for various capacities and locations.

The cost-effectiveness of using chronic kidney disease risk scores to screen for early-stage chronic kidney disease.

Science.gov (United States)

Yarnoff, Benjamin O; Hoerger, Thomas J; Simpson, Siobhan K; Leib, Alyssa; Burrows, Nilka R; Shrestha, Sundar S; Pavkov, Meda E

2017-03-13

Better treatment during early stages of chronic kidney disease (CKD) may slow progression to end-stage renal disease and decrease associated complications and medical costs. Achieving early treatment of CKD is challenging, however, because a large fraction of persons with CKD are unaware of having this disease. Screening for CKD is one important method for increasing awareness. We examined the cost-effectiveness of identifying persons for early-stage CKD screening (i.e., screening for moderate albuminuria) using published CKD risk scores. We used the CKD Health Policy Model, a micro-simulation model, to simulate the cost-effectiveness of using CKD two published risk scores by Bang et al. and Kshirsagar et al. to identify persons in the US for CKD screening with testing for albuminuria. Alternative risk score thresholds were tested (0.20, 0.15, 0.10, 0.05, and 0.02) above which persons were assigned to receive screening at alternative intervals (1-, 2-, and 5-year) for follow-up screening if the first screening was negative. We examined incremental cost-effectiveness ratios (ICERs), incremental lifetime costs divided by incremental lifetime QALYs, relative to the next higher screening threshold to assess cost-effectiveness. Cost-effective scenarios were determined as those with ICERs less than $50,000 per QALY. Among the cost-effective scenarios, the optimal scenario was determined as the one that resulted in the highest lifetime QALYs. ICERs ranged from $8,823 per QALY to $124,626 per QALY for the Bang et al. risk score and $6,342 per QALY to $405,861 per QALY for the Kshirsagar et al. risk score. The Bang et al. risk score with a threshold of 0.02 and 2-year follow-up screening was found to be optimal because it had an ICER less than $50,000 per QALY and resulted in the highest lifetime QALYs. This study indicates that using these CKD risk scores may allow clinicians to cost-effectively identify a broader population for CKD screening with testing for albuminuria

The effects of LT-SN on energy dissipation and lifetime in wireless sensor networks

Directory of Open Access Journals (Sweden)

Zeydin Pala

2016-11-01

Full Text Available Wireless sensor networks (WSNs still attract the attention of researchers, users and the private sector despite their low power and low range tendency for malfunction. This attraction towards WSNs results from their low cost structure and the solutions they offer for many prevalent problems. Many conditions, which remain unforeseen or unexpected during the design of the system, may arise after the initialization of the system. Similarly, many situations where security vulnerabilities take place may emerge in time in WSNs operating normally. In this study, we called nodes which enter sleeping mode without any further waking up and causing a sparser number of nodes in the network without any function in data transmission as Long-Term Sleep Nodes (LT-SN; and considered energy spaces caused by such nodes as a problem; and established two Linear Programming (LP models based on the efficiency of the present nodes. We offered two different models which present the effect of sensor nodes, which were initially operating in wireless sensor network environment and did not wake up following sleep mode, on network lifetime. The results of the present study report that as the number of LT-SN increases, the lifetime of the network decreases.

Cost-effectiveness of sacubitril/valsartan in chronic heart-failure patients with reduced ejection fraction.

Science.gov (United States)

Ademi, Zanfina; Pfeil, Alena M; Hancock, Elizabeth; Trueman, David; Haroun, Rola Haroun; Deschaseaux, Celine; Schwenkglenks, Matthias

2017-11-29

We aimed to assess the cost effectiveness of sacubitril/valsartan compared to angiotensin-converting enzyme inhibitors (ACEIs) for the treatment of individuals with chronic heart failure and reduced-ejection fraction (HFrEF) from the perspective of the Swiss health care system. The cost-effectiveness analysis was implemented as a lifelong regression-based cohort model. We compared sacubitril/valsartan with enalapril in chronic heart failure patients with HFrEF and New York-Heart Association Functional Classification II-IV symptoms. Regression models based on the randomised clinical phase III PARADIGM-HF trials were used to predict events (all-cause mortality, hospitalisations, adverse events and quality of life) for each treatment strategy modelled over the lifetime horizon, with adjustments for patient characteristics. Unit costs were obtained from Swiss public sources for the year 2014, and costs and effects were discounted by 3%. The main outcome of interest was the incremental cost-effectiveness ratio (ICER), expressed as cost per quality-adjusted life years (QALYs) gained. Deterministic sensitivity analysis (DSA) and scenario and probabilistic sensitivity analysis (PSA) were performed. In the base-case analysis, the sacubitril/valsartan strategy showed a decrease in the number of hospitalisations (6.0% per year absolute reduction) and lifetime hospital costs by 8.0% (discounted) when compared with enalapril. Sacubitril/valsartan was predicted to improve overall and quality-adjusted survival by 0.50 years and 0.42 QALYs, respectively. Additional net-total costs were CHF 10 926. This led to an ICER of CHF 25 684. In PSA, the probability of sacubitril/valsartan being cost-effective at thresholds of CHF 50 000 was 99.0%. The treatment of HFrEF patients with sacubitril/valsartan versus enalapril is cost effective, if a willingness-to-pay threshold of CHF 50 000 per QALY gained ratio is assumed.

Effects of Orbital Lifetime Reduction on the Long-Term Earth Satellite Population as Modeled by EVOLVE 4.0

Science.gov (United States)

Krisko, Paula H.; Opiela, John N.; Liou, Jer-Chyi; Anz-Meador, Phillip D.; Theall, Jeffrey R.

1999-01-01

The latest update of the NASA orbital debris environment model, EVOLVE 4.0, has been used to study the effect of various proposed debris mitigation measures, including the NASA 25-year guideline. EVOLVE 4.0, which includes updates of the NASA breakup, solar activity, and the orbit propagator models, a GEO analysis option, and non-fragmentation debris source models, allows for the statistical modeling and predicted growth of the particle population >1 mm in characteristic length in LEO and GEO orbits. The initial implementation of this &odel has been to study the sensitivity of the overall LEO debris environment to mitigation measures designed to limit the lifetime of intact objects in LEO orbits. The mitigation measures test matrix for this study included several commonly accepted testing schemes, i.e., the variance of the maximum LEO lifetime from 10 to 50 years, the date of the initial implementation of this policy, the shut off of all explosions at some specified date, and the inclusion of disposal orbits. All are timely studies in that all scenarios have been suggested by researchers and satellite operators as options for the removal of debris from LEO orbits.

Lifetime physical activity and female stress urinary incontinence.

Science.gov (United States)

Nygaard, Ingrid E; Shaw, Janet M; Bardsley, Tyler; Egger, Marlene J

2015-07-01

We sought to estimate whether moderate/severe stress urinary incontinence (SUI) in middle-aged women is associated with overall lifetime physical activity (including leisure, household, outdoor, and occupational), as well as lifetime leisure (recreational), lifetime strenuous, and strenuous activity during the teen years. Recruitment for this case-control study was conducted in primary-care-level family medicine and gynecology clinics. A total of 1538 enrolled women ages 39-65 years underwent a Pelvic Organ Prolapse Quantification examination to assess vaginal support. Based on Incontinence Severity Index scores, cases had moderate/severe and controls had no/mild SUI. We excluded 349 with vaginal descent at/below the hymen (pelvic organ prolapse), 194 who did not return questionnaires, and 110 with insufficient activity data for analysis. In all, 213 cases were frequency matched 1:1 by age group to controls. Physical activity was measured using the Lifetime Physical Activity Questionnaire, in which women recall activity from menarche to present. We created separate multivariable logistic regression models for activity measures. SUI odds increased slightly with overall lifetime activity (odds ratio [OR], 1.20 per 70 additional metabolic equivalent of task-h/wk; 95% confidence interval [CI], 1.02-1.41), and were not associated with lifetime strenuous activity (OR, 1.11; 95% CI, 0.99-1.25). In quintile analysis of lifetime leisure activity, which demonstrated a nonlinear pattern, all quintiles incurred about half the odds of SUI compared to reference (second quintile; P = .009). Greater strenuous activity in teen years modestly increased SUI odds (OR, 1.37 per 7 additional h/wk; 95% CI, 1.09-1.71); OR, 1.75; 95% CI, 1.15-2.66 in sensitivity analysis adjusting for measurement error. The predicted probability of SUI rose linearly in women exceeding 7.5 hours of strenuous activity/wk during teen years. Teen strenuous activity had a similar effect on SUI odds when

Are financial incentives cost-effective to support smoking cessation during pregnancy?

Science.gov (United States)

Boyd, Kathleen A; Briggs, Andrew H; Bauld, Linda; Sinclair, Lesley; Tappin, David

2016-02-01

To investigate the cost-effectiveness of up to £400 worth of financial incentives for smoking cessation in pregnancy as an adjunct to routine health care. Cost-effectiveness analysis based on a Phase II randomized controlled trial (RCT) and a cost-utility analysis using a life-time Markov model. The RCT was undertaken in Glasgow, Scotland. The economic analysis was undertaken from the UK National Health Service (NHS) perspective. A total of 612 pregnant women randomized to receive usual cessation support plus or minus financial incentives of up to £400 vouchers (US $609), contingent upon smoking cessation. Comparison of usual support and incentive interventions in terms of cotinine-validated quitters, quality-adjusted life years (QALYs) and direct costs to the NHS. The incremental cost per quitter at 34-38 weeks pregnant was £1127 ($1716).This is similar to the standard look-up value derived from Stapleton & West's published ICER tables, £1390 per quitter, by looking up the Cessation in Pregnancy Incentives Trial (CIPT) incremental cost (£157) and incremental 6-month quit outcome (0.14). The life-time model resulted in an incremental cost of £17 [95% confidence interval (CI) = -£93, £107] and a gain of 0.04 QALYs (95% CI = -0.058, 0.145), giving an ICER of £482/QALY ($734/QALY). Probabilistic sensitivity analysis indicates uncertainty in these results, particularly regarding relapse after birth. The expected value of perfect information was £30 million (at a willingness to pay of £30 000/QALY), so given current uncertainty, additional research is potentially worthwhile. Financial incentives for smoking cessation in pregnancy are highly cost-effective, with an incremental cost per quality-adjusted life years of £482, which is well below recommended decision thresholds. © 2015 Society for the Study of Addiction.

Cost-effectiveness analysis of umeclidinium/vilanterol for the management of patients with moderate to very severe COPD using an economic model.

Science.gov (United States)

Wilson, Michele R; Patel, Jeetvan G; Coleman, Amber; McDade, Cheryl L; Stanford, Richard H; Earnshaw, Stephanie R

2017-01-01

Bronchodilators such as long-acting muscarinic antagonists (LAMAs) and long-acting β 2 -agonists (LABAs) are central to the pharmacological management of COPD. Dual bronchodilation with umeclidinium/vilanterol (UMEC/VI; 62.5/25 μg) is a novel LAMA/LABA combination approved for maintenance treatment for patients with COPD. The objective of this study was to assess the cost-effectiveness of maintenance treatment with UMEC/VI compared with tiotropium (TIO) 18 μg, open dual LAMA + LABA treatment, or no long-acting bronchodilator treatment in patients with moderate to very severe COPD. A Markov model was developed to estimate the costs and outcomes associated with UMEC/VI treatment in patients with moderate to very severe COPD (GSK study number: HO-13-13411). Clinical efficacy, costs, utilities, and mortality obtained from the published literature were used as the model inputs. Costs are presented in US dollars based on 2015 prices. The model outputs are total costs, drug costs, other medical costs, number of COPD exacerbations, and quality-adjusted life-years (QALYs). Costs and outcomes were discounted at a 3% annual rate. Incremental cost-effectiveness ratios were calculated. One-way and probabilistic sensitivity analyses were conducted to assess the effects of changing parameters on the uncertainty of the results. UMEC/VI treatment for moderate to very severe COPD was associated with lower lifetime medical costs ($82,344) compared with TIO ($88,822), open dual LAMA + LABA treatment ($114,442), and no long-acting bronchodilator ($86,751). Fewer exacerbations were predicted to occur with UMEC/VI treatment compared with no long-acting bronchodilator treatment. UMEC/VI provided an 0.11 and 0.25 increase in QALYs compared with TIO and no long-acting bronchodilator treatment, and as such, dominated these cost-effectiveness analyses. Sensitivity analyses confirmed that the results were robust. The results from this model suggest that UMEC/VI treatment would be dominant

Precision lifetime measurements

International Nuclear Information System (INIS)

Tanner, C.E.

1994-01-01

Precision measurements of atomic lifetimes provide important information necessary for testing atomic theory. The authors employ resonant laser excitation of a fast atomic beam to measure excited state lifetimes by observing the decay-in-flight of the emitted fluorescence. A similar technique was used by Gaupp, et al., who reported measurements with precisions of less than 0.2%. Their program includes lifetime measurements of the low lying p states in alkali and alkali like systems. Motivation for this work comes from a need to test the atomic many-body-perturbation theory (MBPT) that is necessary for interpretation of parity nonconservation experiments in atomic cesium. The authors have measured the cesium 6p 2 P 1/2 and 6p 2 P 3/2 state lifetimes to be 34.934±0.094 ns and 30.499±0.070 ns respectively. With minor changes to the apparatus, they have extended their measurements to include the lithium 2p 2 P 1/2 and 2p 2 P 3/2 states

Cost-effectiveness of rosuvastatin 20 mg for the prevention of cardiovascular morbidity and mortality: a Swedish economic evaluation of the JUPITER trial.

Science.gov (United States)

Ohsfeldt, Robert L; Olsson, Anders G; Jensen, Marie M; Gandhi, Sanjay K; Paulsson, Thomas

2012-01-01

This study estimated the long-term health outcomes, healthcare costs, and cost-effectiveness of rosuvastatin 20 mg therapy in primary prevention of major cardiovascular disease (CVD) in a Swedish population. Based on data from the JUPITER trial, long-term CVD outcomes with rosuvastatin vs no active treatment were estimated for patients with an elevated baseline CVD risk (Framingham CVD score >20%, sub-population of JUPITER population) and for a population similar to the total JUPITER population. Using a decision-analytic model, trial CVD event rates were combined with epidemiological and cost data specific for Sweden. First and subsequent CVD events and death were estimated over a lifetime perspective. The observed relative risk reduction was extrapolated beyond the trial duration. Incremental effectiveness was measured as life-years gained (LYG) and quality-adjusted life-years (QALYs) gained. Treating 100,000 patients with rosuvastatin 20 mg was estimated to avoid 14,692 CVD events over the lifetime (8021 non-fatal MIs, 3228 non-fatal strokes, and 4924 CVD deaths) compared to placebo. This translated into an estimated gain of 42,122 QALYs and 36,865 total life years (LYG). Rosuvastatin was both more effective and less costly over a lifetime perspective, and rosuvastatin is subsequently a dominant alternative compared to no treatment in the assessed population. Using the overall JUPITER population, rosuvastatin was dominant for the lifetime horizon. In the sensitivity analysis, rosuvastatin was the dominant treatment strategy over a 20-year time horizon, and cost-effective with an incremental cost-effectiveness ratio (cost per QALY) of SEK 1783 over a 10-year time horizon. Some model inputs were derived from literature or other data sources, but uncertainty was controlled by sensitivity analyses. Results indicate that rosuvastatin 20 mg treatment is a cost-effective option vs no-treatment in patients with Framingham CVD risk >20% in Sweden and might even be

Lifetime estimation for the power semiconductors considering mission profiles in wind power converter

DEFF Research Database (Denmark)

Ma, Ke; Liserre, Marco; Blaabjerg, Frede

2013-01-01

for the reliability improvement and also for cost reduction of wind power technology. Unfortunately, the existing lifetime estimation methods for the power electronic converter are not yet suitable in the wind power application, because the comprehensive mission profiles are not well specified and included......As a key component in the wind turbine system, power electronic converter and its power semiconductors suffer from adverse power loadings related to environment, and are proven to have certain failure rates. Therefore, correct lifetime estimation of wind power converter is crucial...... estimation, more detailed information for the reliability performance of wind power converter can be obtained....

Cost-effectiveness of antibiotic prophylaxis for dental patients with prosthetic joints: Comparisons of antibiotic regimens for patients with total hip arthroplasty.

Science.gov (United States)

Skaar, Daniel D; Park, Taehwan; Swiontkowski, Marc F; Kuntz, Karen M

2015-11-01

Clinician uncertainty concerning the need for antibiotic prophylaxis to prevent prosthetic joint infection (PJI) after undergoing dental procedures persists. Improved understanding of the potential clinical and economic risks and benefits of antibiotic prophylaxis will help inform the debate and facilitate the continuing evolution of clinical management guidelines for dental patients with prosthetic joints. The authors developed a Markov decision model to compare the lifetime cost-effectiveness of alternative antibiotic prophylaxis strategies for dental patients aged 65 years who had undergone total hip arthroplasty (THA). On the basis of the authors' interpretation of previous recommendations from the American Dental Association and American Academy of Orthopaedic Surgeons, they compared the following strategies: no prophylaxis, prophylaxis for the first 2 years after arthroplasty, and lifetime prophylaxis. A strategy of foregoing antibiotic prophylaxis before dental visits was cost-effective and resulted in lower lifetime accumulated costs ($11,909) and higher accumulated quality-adjusted life years (QALYs) (12.375) when compared with alternative prophylaxis strategies. The results of Markov decision modeling indicated that a no-antibiotic prophylaxis strategy was cost-effective for dental patients who had undergone THA. These results support the findings of case-control studies and the conclusions of an American Dental Association Council on Scientific Affairs report that questioned general recommendations for antibiotic prophylaxis before dental procedures. The results of cost-effectiveness decision modeling support the contention that routine antibiotic prophylaxis for dental patients with total joint arthroplasty should be reconsidered. Copyright © 2015 American Dental Association. Published by Elsevier Inc. All rights reserved.

Mining the bulk positron lifetime

International Nuclear Information System (INIS)

Aourag, H.; Guittom, A.

2009-01-01

We introduce a new approach to investigate the bulk positron lifetimes of new systems based on data-mining techniques. Through data mining of bulk positron lifetimes, we demonstrate the ability to predict the positron lifetimes of new semiconductors on the basis of available semiconductor data already studied. Informatics techniques have been applied to bulk positron lifetimes for different tetrahedrally bounded semiconductors in order to discover computational design rules. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

On the Impacts of PV Array Sizing on the Inverter Reliability and Lifetime

DEFF Research Database (Denmark)

Sangwongwanich, Ariya; Yang, Yongheng; Sera, Dezso

2018-01-01

, the total energy yield can be increased under weak solar irradiance conditions. However, oversizing the PV array will increase the loading of PV inverters, which may have undesired influence on the PV inverter reliability and lifetime. In that case, it may result in a negative impact on the overall PV...... energy cost, due to the increased maintenance for the PV inverters. With the above concern, this paper evaluates the reliability and lifetime of PV inverters considering the PV array sizing. The evaluation is based on the mission profile of the installation sites in Denmark and Arizona, where...... the reliability-critical components such as power devices and capacitors are considered. The results reveal that the variation in the PV array sizing can considerably deviate the reliability performance and lifetime expectation of PV inverters, especially for those installed in Denmark, where the average solar...

Prasugrel compared to clopidogrel in patients with acute coronary syndrome undergoing percutenaous coronary intervention: a Spanish model-based cost effectiveness analysis.

Science.gov (United States)

Davies, A; Sculpher, M; Barrett, A; Huete, T; Sacristán, J A; Dilla, T

2013-01-01

To assess the long-term cost-effectiveness of 12 months treatment of prasugrel compared to clopidogrel in patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI) in the Spanish health care system. A Markov state transition model was developed to estimate health outcomes, quality adjusted life years (QALYs), life years (LY), and costs over patients' lifetimes. Clinical inputs were based on an analysis of the TRITON-TIMI 38 clinical trial. Hospital readmissions captured during the trial in a sub-study of patients from eight countries (and subsequent re-hospitalisations modelled to accrue beyond the time horizon of the trial), were assigned to Spanish diagnosis-related group payment schedules to estimate hospitalisation costs. Mean total treatment costs were ?11,427 and ?10,910 for prasugrel and clopidogrel respectively. The mean cost of the study drug was ?538 higher for prasugrel vs. clopidogrel, but rehospitalisation costs at 12 months were ?79 lower for prasugrel due to reduced rates of revascularisation. Hospitalisation costs beyond 12 months were higher with prasugrel by ?55, due to longer life expectancy (+0.071 LY and +0.054 QALYs) associated with the decreased nonfatal myocardial infarction rate in the prasugrel group. The incremental cost per life year and QALY gained with prasugrel was ?7,198, and ?9,489, respectively. Considering a willingness-to-pay threshold of ?30,000/QALY gained in the Spanish setting, prasugrel represents a cost-effective option in comparison with clopidogrel among patients with ACS undergoing PCI. Copyright © 2013 SEFH. Published by AULA MEDICA. All rights reserved.

Cost-effectiveness of investing in sidewalks as a means of increasing physical activity: a RESIDE modelling study.

Science.gov (United States)

Veerman, J Lennert; Zapata-Diomedi, Belen; Gunn, Lucy; McCormack, Gavin R; Cobiac, Linda J; Mantilla Herrera, Ana Maria; Giles-Corti, Billie; Shiell, Alan

2016-09-20

Studies consistently find that supportive neighbourhood built environments increase physical activity by encouraging walking and cycling. However, evidence on the cost-effectiveness of investing in built environment interventions as a means of promoting physical activity is lacking. In this study, we assess the cost-effectiveness of increasing sidewalk availability as one means of encouraging walking. Using data from the RESIDE study in Perth, Australia, we modelled the cost impact and change in health-adjusted life years (HALYs) of installing additional sidewalks in established neighbourhoods. Estimates of the relationship between sidewalk availability and walking were taken from a previous study. Multistate life table models were used to estimate HALYs associated with changes in walking frequency and duration. Sensitivity analyses were used to explore the impact of variations in population density, discount rates, sidewalk costs and the inclusion of unrelated healthcare costs in added life years. Installing and maintaining an additional 10 km of sidewalk in an average neighbourhood with 19 000 adult residents was estimated to cost A$4.2 million over 30 years and gain 24 HALYs over the lifetime of an average neighbourhood adult resident population. The incremental cost-effectiveness ratio was A$176 000/HALY. However, sensitivity results indicated that increasing population densities improves cost-effectiveness. In low-density cities such as in Australia, installing sidewalks in established neighbourhoods as a single intervention is unlikely to cost-effectively improve health. Sidewalks must be considered alongside other complementary elements of walkability, such as density, land use mix and street connectivity. Population density is particularly important because at higher densities, more residents are exposed and this improves the cost-effectiveness. Health gain is one of many benefits of enhancing neighbourhood walkability and future studies might

Safeguards First Principle Initiative (SFPI) Cost Model

International Nuclear Information System (INIS)

Price, Mary Alice

2010-01-01

The Nevada Test Site (NTS) began operating Material Control and Accountability (MC and A) under the Safeguards First Principle Initiative (SFPI), a risk-based and cost-effective program, in December 2006. The NTS SFPI Comprehensive Assessment of Safeguards Systems (COMPASS) Model is made up of specific elements (MC and A plan, graded safeguards, accounting systems, measurements, containment, surveillance, physical inventories, shipper/receiver differences, assessments/performance tests) and various sub-elements, which are each assigned effectiveness and contribution factors that when weighted and rated reflect the health of the MC and A program. The MC and A Cost Model, using an Excel workbook, calculates budget and/or actual costs using these same elements/sub-elements resulting in total costs and effectiveness costs per element/sub-element. These calculations allow management to identify how costs are distributed for each element/sub-element. The Cost Model, as part of the SFPI program review process, enables management to determine if spending is appropriate for each element/sub-element.

A Humidity-Dependent Lifetime Derating Factor for DC Film Capacitors

DEFF Research Database (Denmark)

Wang, Huai; Reigosa, Paula Diaz; Blaabjerg, Frede

2015-01-01

accelerated testing of film capacitors under different humidity conditions, enabling a more justified lifetime prediction of film capacitors for DC-link applications under specific climatic environments. The analysis of the testing results and the detailed discussion on the derating factor with different......Film capacitors are widely assumed to have superior reliability performance than Aluminum electrolytic capacitors in DC-link design of power electronic converters. However, the assumption needs to be critically judged especially for applications under high humidity environments. This paper proposes...... a humidity-dependent lifetime derating factor for a type of plastic-boxed metallized DC film capacitors. It overcomes the limitation that the humidity impact is not considered in the state-of-the-art DC film capacitor lifetime models. The lifetime derating factor is obtained based on a total of 8,700 hours...

Desired lifetime and end-of-life desires across adulthood from 20 to 90: a dual-source information model.

Science.gov (United States)

Lang, Frieder R; Baltes, Paul B; Wagner, Gert G

2007-09-01

How long do people want to live, and how does scientific research on aging affect such desires? A dual-source information model proposes that aging expectations and desires are informed differently by two sources: personal experiences on the one hand, and scientific and societal influences on the other. Two studies with independent German national samples explored desires regarding length of life and end of life among adults between the ages of 20 and 90. FINDINGS ARE: First, desired lifetime is consistent at around 85 years with few age differences. Second, experimental induction of good or bad news from research on aging has little effect in Study 1. Third, interest in science has moderating effects on desired lifetime in Study 2. Fourth, there is a high prevalence of a strong desire to control the "when and how" of one's death, although only 11% of the individuals completed a living will. Findings are consistent with the dual-source information model.

Assessing the value of mepolizumab for severe eosinophilic asthma: a cost-effectiveness analysis.

Science.gov (United States)

Whittington, Melanie D; McQueen, R Brett; Ollendorf, Daniel A; Tice, Jeffrey A; Chapman, Richard H; Pearson, Steven D; Campbell, Jonathan D

2017-02-01

Adding mepolizumab to standard treatment with inhaled corticosteroids and controller medications could decrease asthma exacerbations and use of long-term oral steroids in patients with severe disease and increased eosinophils; however, mepolizumab is costly and its cost effectiveness is unknown. To estimate the cost effectiveness of mepolizumab. A Markov model was used to determine the incremental cost per quality-adjusted life year (QALY) gained for mepolizumab plus standard of care (SoC) and for SoC alone. The population, adults with severe eosinophilic asthma, was modeled for a lifetime time horizon. A responder scenario analysis was conducted to determine the cost effectiveness for a cohort able to achieve and maintain asthma control. Over a lifetime treatment horizon, 23.96 exacerbations were averted per patient receiving mepolizumab plus SoC. Avoidance of exacerbations and decrease in long-term oral steroid use resulted in more than $18,000 in cost offsets among those receiving mepolizumab, but treatment costs increased by more than $600,000. Treatment with mepolizumab plus SoC vs SoC alone resulted in a cost-effectiveness estimate of $386,000 per QALY. To achieve cost effectiveness of approximately $150,000 per QALY, mepolizumab would require a more than 60% price discount. At current pricing, treating a responder cohort yielded cost-effectiveness estimates near $160,000 per QALY. The estimated cost effectiveness of mepolizumab exceeds value thresholds. Achieving these thresholds would require significant discounts from the current list price. Alternatively, treatment limited to responders improves the cost effectiveness toward, but remains still slightly above, these thresholds. Payers interested in improving the efficiency of health care resources should consider negotiations of the mepolizumab price and ways to predict and assess the response to mepolizumab. Copyright © 2016 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All

Advanced fuel cycle cost estimation model and its cost estimation results for three nuclear fuel cycles using a dynamic model in Korea

Energy Technology Data Exchange (ETDEWEB)

Kim, Sungki, E-mail: sgkim1@kaeri.re.kr [Korea Atomic Energy Research Institute, 1045 Daedeokdaero, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Ko, Wonil [Korea Atomic Energy Research Institute, 1045 Daedeokdaero, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Youn, Saerom; Gao, Ruxing [University of Science and Technology, 217 Gajungro, Yuseong-gu, Daejeon 305-350 (Korea, Republic of); Bang, Sungsig, E-mail: ssbang@kaist.ac.kr [Korea Advanced Institute of Science and Technology, Department of Business and Technology Management, 291 Deahak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

2015-11-15

Highlights: • The nuclear fuel cycle cost using a new cost estimation model was analyzed. • The material flows of three nuclear fuel cycle options were calculated. • The generation cost of once-through was estimated to be 66.88 mills/kW h. • The generation cost of pyro-SFR recycling was estimated to be 78.06 mills/kW h. • The reactor cost was identified as the main cost driver of pyro-SFR recycling. - Abstract: The present study analyzes advanced nuclear fuel cycle cost estimation models such as the different discount rate model and its cost estimation results. To do so, an analysis of the nuclear fuel cycle cost of three options (direct disposal (once through), PWR–MOX (Mixed OXide fuel), and Pyro-SFR (Sodium-cooled Fast Reactor)) from the viewpoint of economic sense, focusing on the cost estimation model, was conducted using a dynamic model. From an analysis of the fuel cycle cost estimation results, it was found that some cost gap exists between the traditional same discount rate model and the advanced different discount rate model. However, this gap does not change the priority of the nuclear fuel cycle option from the viewpoint of economics. In addition, the fuel cycle costs of OT (Once-Through) and Pyro-SFR recycling based on the most likely value using a probabilistic cost estimation except for reactor costs were calculated to be 8.75 mills/kW h and 8.30 mills/kW h, respectively. Namely, the Pyro-SFR recycling option was more economical than the direct disposal option. However, if the reactor cost is considered, the economic sense in the generation cost between the two options (direct disposal vs. Pyro-SFR recycling) can be changed because of the high reactor cost of an SFR.

Clinical benefits, costs, and cost-effectiveness of neonatal intensive care in Mexico.

Directory of Open Access Journals (Sweden)

Jochen Profit

2010-12-01

Full Text Available Neonatal intensive care improves survival, but is associated with high costs and disability amongst survivors. Recent health reform in Mexico launched a new subsidized insurance program, necessitating informed choices on the different interventions that might be covered by the program, including neonatal intensive care. The purpose of this study was to estimate the clinical outcomes, costs, and cost-effectiveness of neonatal intensive care in Mexico.A cost-effectiveness analysis was conducted using a decision analytic model of health and economic outcomes following preterm birth. Model parameters governing health outcomes were estimated from Mexican vital registration and hospital discharge databases, supplemented with meta-analyses and systematic reviews from the published literature. Costs were estimated on the basis of data provided by the Ministry of Health in Mexico and World Health Organization price lists, supplemented with published studies from other countries as needed. The model estimated changes in clinical outcomes, life expectancy, disability-free life expectancy, lifetime costs, disability-adjusted life years (DALYs, and incremental cost-effectiveness ratios (ICERs for neonatal intensive care compared to no intensive care. Uncertainty around the results was characterized using one-way sensitivity analyses and a multivariate probabilistic sensitivity analysis. In the base-case analysis, neonatal intensive care for infants born at 24-26, 27-29, and 30-33 weeks gestational age prolonged life expectancy by 28, 43, and 34 years and averted 9, 15, and 12 DALYs, at incremental costs per infant of US$11,400, US$9,500, and US$3,000, respectively, compared to an alternative of no intensive care. The ICERs of neonatal intensive care at 24-26, 27-29, and 30-33 weeks were US$1,200, US$650, and US$240, per DALY averted, respectively. The findings were robust to variation in parameter values over wide ranges in sensitivity analyses

Estimation of the lifetime distribution of mechatronic systems in the presence of a covariate: A comparison among parametric, semiparametric and nonparametric models

International Nuclear Information System (INIS)

Bobrowski, Sebastian; Chen, Hong; Döring, Maik; Jensen, Uwe; Schinköthe, Wolfgang

2015-01-01

In practice manufacturers may have lots of failure data of similar products using the same technology basis under different operating conditions. Thus, one can try to derive predictions for the distribution of the lifetime of newly developed components or new application environments through the existing data using regression models based on covariates. Three categories of such regression models are considered: a parametric, a semiparametric and a nonparametric approach. First, we assume that the lifetime is Weibull distributed, where its parameters are modelled as linear functions of the covariate. Second, the Cox proportional hazards model, well-known in Survival Analysis, is applied. Finally, a kernel estimator is used to interpolate between empirical distribution functions. In particular the last case is new in the context of reliability analysis. We propose a goodness of fit measure (GoF), which can be applied to all three types of regression models. Using this GoF measure we discuss a new model selection procedure. To illustrate this method of reliability prediction, the three classes of regression models are applied to real test data of motor experiments. Further the performance of the approaches is investigated by Monte Carlo simulations. - Highlights: • We estimate the lifetime distribution in the presence of a covariate. • Three types of regression models are considered and compared. • A new nonparametric estimator based on our particular data structure is introduced. • We propose a goodness of fit measure and show a new model selection procedure. • A case study with real data and Monte Carlo simulations are performed

NASA Instrument Cost/Schedule Model

Science.gov (United States)

Habib-Agahi, Hamid; Mrozinski, Joe; Fox, George

2011-01-01

NASA's Office of Independent Program and Cost Evaluation (IPCE) has established a number of initiatives to improve its cost and schedule estimating capabilities. 12One of these initiatives has resulted in the JPL developed NASA Instrument Cost Model. NICM is a cost and schedule estimator that contains: A system level cost estimation tool; a subsystem level cost estimation tool; a database of cost and technical parameters of over 140 previously flown remote sensing and in-situ instruments; a schedule estimator; a set of rules to estimate cost and schedule by life cycle phases (B/C/D); and a novel tool for developing joint probability distributions for cost and schedule risk (Joint Confidence Level (JCL)). This paper describes the development and use of NICM, including the data normalization processes, data mining methods (cluster analysis, principal components analysis, regression analysis and bootstrap cross validation), the estimating equations themselves and a demonstration of the NICM tool suite.

Dynamic aperture study and lifetime improvement at the Advanced Photon Source

International Nuclear Information System (INIS)

Sajaev, V.; Emery, L.

2006-01-01

Over the past few years, the optics of the Advanced Photon Source storage ring has been optimized to provide lower natural emittance. Presently, the APS operates at 2.5 nm-rad emittance. The optimization was done at the expense of stronger sextupoles and shorter lifetime. Here we present our work on measurement and understanding of the dynamic aperture of the APS in low-emittance mode. We found good agreement between the dynamic aperture measurements and that of the model derived from the response matrix analysis. Based on the model, we were able to increase the lifetime significantly by optimizing sextupoles, correcting optics, moving a working point, and adjusting rf voltage. The higher lifetime allowed us to decrease operating coupling from 2.5% to 1%.

Plural Governance: A Modified Transaction Cost Model

DEFF Research Database (Denmark)

Mols, Niels Peter; Menard, Claude

2014-01-01

Plural governance is a form of governance where a firm both makes and buys similar goods or services. Despite a widespread use of plural governance there are no transaction cost models of how plural governance affects performance. This paper reviews the literature about plural forms and proposes...... a model relating transaction cost and resource-based variables to the cost of the plural form. The model is then used to analyze when the plural form is efficient compared to alternative governance structures. We also use the model to discuss the strength of three plural form synergies....

Optimisation of decision making under uncertainty throughout field lifetime: A fractured reservoir example

Science.gov (United States)

Arnold, Dan; Demyanov, Vasily; Christie, Mike; Bakay, Alexander; Gopa, Konstantin

2016-10-01

Assessing the change in uncertainty in reservoir production forecasts over field lifetime is rarely undertaken because of the complexity of joining together the individual workflows. This becomes particularly important in complex fields such as naturally fractured reservoirs. The impact of this problem has been identified in previous and many solutions have been proposed but never implemented on complex reservoir problems due to the computational cost of quantifying uncertainty and optimising the reservoir development, specifically knowing how many and what kind of simulations to run. This paper demonstrates a workflow that propagates uncertainty throughout field lifetime, and into the decision making process by a combination of a metric-based approach, multi-objective optimisation and Bayesian estimation of uncertainty. The workflow propagates uncertainty estimates from appraisal into initial development optimisation, then updates uncertainty through history matching and finally propagates it into late-life optimisation. The combination of techniques applied, namely the metric approach and multi-objective optimisation, help evaluate development options under uncertainty. This was achieved with a significantly reduced number of flow simulations, such that the combined workflow is computationally feasible to run for a real-field problem. This workflow is applied to two synthetic naturally fractured reservoir (NFR) case studies in appraisal, field development, history matching and mid-life EOR stages. The first is a simple sector model, while the second is a more complex full field example based on a real life analogue. This study infers geological uncertainty from an ensemble of models that are based on the carbonate Brazilian outcrop which are propagated through the field lifetime, before and after the start of production, with the inclusion of production data significantly collapsing the spread of P10-P90 in reservoir forecasts. The workflow links uncertainty

Self-Organized Criticality and Scaling in Lifetime of Traffic Jams

Science.gov (United States)

Nagatani, Takashi

1995-01-01

The deterministic cellular automaton 184 (the one-dimensional asymmetric simple-exclusion model with parallel dynamics) is extended to take into account injection or extraction of particles. The model presents the traffic flow on a highway with inflow or outflow of cars.Introducing injection or extraction of particles into the asymmetric simple-exclusion model drives the system asymptotically into a steady state exhibiting a self-organized criticality. The typical lifetime of traffic jams scales as \\cong Lν with ν=0.65±0.04. It is shown that the cumulative distribution Nm (L) of lifetimes satisfies the finite-size scaling form Nm (L) \\cong L-1 f(m/Lν).

Temperature variations of average o-Ps lifetime in porous media

CERN Document Server

Goworek, T; Jasinska, B; Wawryszczuk, J

2000-01-01

Modification of the Tao-Eldrup model is proposed in order to extend its usefulness to the case of porous media. The modification consists in the transition from spherical to capillary geometry and in inclusion of pick-off annihilation from the excited states of a particle in the well. Approximated equations for pick-off constant in these states are given. The model was tested by observing the temperature dependences of o-Ps lifetime in various media. In the case of silica gels and Vycor glass with narrow pores, the model seems to work well, while for larger pores in Vycor unexpectedly long lifetimes appear in the range of lowest temperatures.

Cost functions of greenhouse models

International Nuclear Information System (INIS)

Linderoth, H.

2000-01-01

The benchmark is equal to the cost (D) caused by an increase in temperature since the middle of the nineteenth century (T) of nearly 2.5 deg. C. According to mainstream economists, the benchmark is 1-2% of GDP, but very different estimates can also be found. Even though there appears to be agreement among a number of economists that the benchmark is 1-2% of GDP, major differences exist when it comes to estimating D for different sectors. One of the main problems is how to estimate non-market activities. Normally, the benchmark is the best guess, but due to the possibility of catastrophic events this can be considerable smaller than the mean. Certainly, the cost function is skewed to the right. The benchmark is just one point on the cost curve. To a great extent, cost functions are alike in greenhouse models (D = α ''.T'' λ). Cost functions are region and sector dependent in several models. In any case, both α (benchmark) and λ are rough estimates. Besides being dependent on α and λ, the marginal emission cost depends on the discount rate. In fact, because emissions have effects continuing for many years, the discount rate is clearly the most important parameter. (au) (au)

Towards low cost, efficient and stable organic photovoltaic modules

Energy Technology Data Exchange (ETDEWEB)

Andriessen, R. [Holst Centre - Solliance, PO Box 8550, 5605 KN Eindhoven (Netherlands); Kroon, J.M. [ECN - Solliance, Petten (Netherlands); Aernouts, T. [Imec, Solliance, Kapeldreef 75, B-3001 Leuven (Belgium); Janssen, R. [Eindhoven University of Technology, Solliance, Eindhoven (Netherlands)

2012-09-15

This article describes how the Solliance Organic PhotoVoltaics (OPV) shared research Program addresses efficiency, lifetime and production costs for (near) future OPV applications. The balance of these three parameters depends of the envisaged application, but at the end, OPV should be able to compete somehow with Si PV in the future. Efficiency improvements are realized by developing new materials, by exploring and optimizing new device structures and novel interconnection technologies. Lifetime improvements are realized by using stabilized device stacks and materials and by applying high end flexible barriers. Production cost control is done by using a home made Cost of Ownership tool which guides towards the use of low-cost materials and processes.

Model checking exact cost for attack scenarios

DEFF Research Database (Denmark)

Aslanyan, Zaruhi; Nielson, Flemming

2017-01-01

Attack trees constitute a powerful tool for modelling security threats. Many security analyses of attack trees can be seamlessly expressed as model checking of Markov Decision Processes obtained from the attack trees, thus reaping the benefits of a coherent framework and a mature tool support....... However, current model checking does not encompass the exact cost analysis of an attack, which is standard for attack trees. Our first contribution is the logic erPCTL with cost-related operators. The extended logic allows to analyse the probability of an event satisfying given cost bounds and to compute...... the exact cost of an event. Our second contribution is the model checking algorithm for erPCTL. Finally, we apply our framework to the analysis of attack trees....

Cost-effectiveness analysis of cervical cancer prevention based on a rapid human papillomavirus screening test in a high-risk region of China.

Science.gov (United States)

Levin, Carol E; Sellors, John; Shi, Ju-Fang; Ma, Li; Qiao, You-lin; Ortendahl, Jesse; O'Shea, Meredith K H; Goldie, Sue J

2010-09-01

This study assessed the cost-effectiveness of a new, rapid human papillomavirus (HPV)-DNA screening test for cervical cancer prevention in the high-risk region of Shanxi, China. Using micro-costing methods, we estimated the resources needed to implement preventive strategies using cervical cytology or HPV-DNA testing, including the Hybrid Capture 2 (hc2) test (QIAGEN Corp., Gaithersburg, MD) and the rapid HPV-DNA careHPV test (QIAGEN). Data were used in a previously published model and empirically calibrated to country-specific epidemiological data. Strategies differed by initial test, targeted age, frequency of screening, number of clinic visits required (1, 2 or 3) and service delivery setting (national, county and township levels). Outcomes included lifetime risk of cancer, years of life saved (YLS), lifetime costs and incremental cost-effectiveness ratios (cost per YLS). For all screening frequencies, the most efficient strategy used 2-visit rapid HPV-DNA testing at the county level, including screening and diagnostics in the first visit, and treatment in the second visit. Screening at ages 35, 40 and 45 reduced cancer risk by 50% among women compliant with all 3 screening rounds, and was US$ 150 per YLS, compared with this same strategy applied twice per lifetime. This would be considered very cost-effective evaluated against China's per-capita gross domestic product (US$ 1,702). By enhancing the linkage between screening and treatment through a reduced number of visits, rapid HPV-DNA testing 3 times per lifetime is more effective than traditional cytology, and is likely to be cost-effective in high-risk regions of China.

The predicted lifetime costs and health consequences of calcium and vitamin D supplementation for fracture preventio

DEFF Research Database (Denmark)

Hagen, G.; Wisløff, T.; Sønbø Kristiansen, Ivar

2016-01-01

Summary: Some studies indicate that calcium supplementation increases cardiovascular risk. We assessed whether such effects could counterbalance the fracture benefits from supplementation. Accounting for cardiovascular outcomes, calcium may cause net harm and would not be cost-effective. Clinicians...... and to evaluate the cost-effectiveness of such supplementation. Methods: We created a probabilistic Markov simulation model that was analysed at the individual patient level. We analysed 65-year-old Norwegian women with a 2.3 % 10-year risk of hip fracture and a 9.3 % risk of any major fracture according......-, and high-risk scenario. Results: Assuming no cardiovascular effects, CaD supplementation produces improved health outcomes resulting in an incremental gain of 0.0223 quality-adjusted life years (QALYs) and increases costs by €322 compared with no treatment (cost-effectiveness ratio €14,453 per QALY gained...

Thermal Loading and Lifetime Estimation for Power Device Considering Mission Profiles in Wind Power Converter

DEFF Research Database (Denmark)

Ma, Ke; Liserre, Marco; Blaabjerg, Frede

2015-01-01

for the reliability improvement and also for cost reduction of wind power technology. Unfortunately, the existing lifetime estimation methods for the power electronic converter are not yet suitable in the wind power application, because the comprehensive mission profiles are not well specified and included......As a key component in the wind turbine system, the power electronic converter and its power semiconductors suffer from complicated power loadings related to environment, and are proven to have high failure rates. Therefore, correct lifetime estimation of wind power converter is crucial...... devices, more detailed information of the lifetime-related performance in wind power converter can be obtained. Some experimental results are also included to validate the thermal behavior of power device under different mission profiles....

Quantitative fluorescence lifetime spectroscopy in turbid media: comparison of theoretical, experimental and computational methods

International Nuclear Information System (INIS)

Vishwanath, Karthik; Mycek, Mary-Ann; Pogue, Brian

2002-01-01

A Monte Carlo model developed to simulate time-resolved fluorescence propagation in a semi-infinite turbid medium was validated against previously reported theoretical and computational results. Model simulations were compared to experimental measurements of fluorescence spectra and lifetimes on tissue-simulating phantoms for single and dual fibre-optic probe geometries. Experiments and simulations using a single probe revealed that scattering-induced artefacts appeared in fluorescence emission spectra, while fluorescence lifetimes were unchanged. Although fluorescence lifetime measurements are generally more robust to scattering artefacts than are measurements of fluorescence spectra, in the dual-probe geometry scattering-induced changes in apparent lifetime were predicted both from diffusion theory and via Monte Carlo simulation, as well as measured experimentally. In all cases, the recovered apparent lifetime increased with increasing scattering and increasing source-detector separation. Diffusion theory consistently underestimated the magnitude of these increases in apparent lifetime (predicting a maximum increase of ∼15%), while Monte Carlo simulations and experiment were closely matched (showing increases as large as 30%). These results indicate that quantitative simulations of time-resolved fluorescence propagation in turbid media will be important for accurate recovery of fluorophore lifetimes in biological spectroscopy and imaging applications. (author)

Global transportation cost modeling for long range planning

International Nuclear Information System (INIS)

Pope, R.B.; Michelhaugh, R.D.; Singley, P.T.; Lester, P.B.

1998-01-01

The U.S. Department of Energy (DOE) is preparing to perform significant remediation activities of the sites for which it is responsible. To accomplish this, it is preparing a corporate global plan focused on activities over the next decade. Significant in these planned activities is the transportation of the waste arising from the remediation. The costs of this transportation are expected to be large. To support the initial assessment of the plan, a cost-estimating model was developed, peer-reviewed against other available packaging and transportation cost data, and applied to significant number of shipping campaigns of radioactive waste. This cost-estimating model, known as the TEn-year Plan TRAnsportation cost Model (TEPTRAM), can be used to model radioactive material shipments between DOE sites or from DOE sites to non-DOE destinations. The model considers the costs for recovering and processing of the wastes, packaging the wastes for transport, and the carriage of the waste. It also provides a rough order-of-magnitude estimate of labor costs associated with preparing nd undertaking the shipments. At the user's direction, the model can also consider the cost of DOE's interactions with its external stakeholders (e.g., state and local governments and tribal entities) and the cost associated with tracking and communicating with the shipments. By considering all of these sources of costs, it provides a mechanism for assessing and comparing the costs of various waste processing and shipping campaign alternatives to help guide decision-making. Recent analyses of specific planned shipments of transuranic (TRU) waste which consider alternative packaging options are described. These analyses show that options are available for significantly reducing total costs while still satisfying regulatory requirements. (authors)

Lifetime results from heavy quark systems

International Nuclear Information System (INIS)

Papadimitriou, V.

1997-11-01

We present the latest measurements of weakly decaying b-hadrons from experiments at e + e - and p anti p colliders. These measurements include the average lifetime of b-hadrons, lifetimes of the B - , B 0 and B 0 s mesons, the average lifetime of b-baryons and lifetimes of the Λ b and Ξ b baryons

Evaluation of Cost Models and Needs & Gaps Analysis

DEFF Research Database (Denmark)