WorldWideScience

Sample records for return period uncertainty

  1. Stochastic long term modelling of a drainage system with estimation of return period uncertainty

    DEFF Research Database (Denmark)

    Thorndahl, Søren

    2009-01-01

    Long term prediction of maximum water levels and combined sewer overflow (CSO) in drainage systems are associated with large uncertainties. Especially on rainfall inputs, parameters, and assessment of return periods. This paper proposes a Monte Carlo based methodology for stochastic prediction of...

  2. Uncertainty in return period analysis of combined sewer overflow effects using embedded Monte Carlo simulations

    NARCIS (Netherlands)

    Grum, M.; Aalderink, R.H.

    1999-01-01

    The rerun periods of detrimental effects ate often used as design criteria in urban storm water management. Considerable uncertainty is associated with the models used. This is either ignored or pooled with the inherent event to event variation such as rainfall depth It is here argued that

  3. Return Predictability, Model Uncertainty, and Robust Investment

    DEFF Research Database (Denmark)

    Lukas, Manuel

    Stock return predictability is subject to great uncertainty. In this paper we use the model confidence set approach to quantify uncertainty about expected utility from investment, accounting for potential return predictability. For monthly US data and six representative return prediction models, we...... find that confidence sets are very wide, change significantly with the predictor variables, and frequently include expected utilities for which the investor prefers not to invest. The latter motivates a robust investment strategy maximizing the minimal element of the confidence set. The robust investor...... allocates a much lower share of wealth to stocks compared to a standard investor....

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

    Science.gov (United States)

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

    2018-04-01

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

  5. Policy Uncertainty, Investment and Commitment Periods

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    Today's investment decisions in key sectors such as energy, forestry or transport have significant impacts on the levels of greenhouse gas (GHG) emissions over the coming decades. Given the economic and environmental long-term implications of capital investment and retirement, a climate mitigation regime should aim to encourage capital investment in climate-friendly technologies. Many factors affect technology choice and the timing of investment, including investor expectations about future prices and policies. Recent international discussions have focused on the importance of providing more certainty about future climate policy stringency. The design of commitment periods can play a role in creating this environment. This paper assesses how the length of commitment periods influences policy uncertainty and investment decisions. In particular, the paper analyses the relationship between commitment period length and near term investment decisions in climate friendly technology.

  6. The dynamic correlation between policy uncertainty and stock market returns in China

    Science.gov (United States)

    Yang, Miao; Jiang, Zhi-Qiang

    2016-11-01

    The dynamic correlation is examined between government's policy uncertainty and Chinese stock market returns in the period from January 1995 to December 2014. We find that the stock market is significantly correlated to policy uncertainty based on the results of the Vector Auto Regression (VAR) and Structural Vector Auto Regression (SVAR) models. In contrast, the results of the Dynamic Conditional Correlation Generalized Multivariate Autoregressive Conditional Heteroscedasticity (DCC-MGARCH) model surprisingly show a low dynamic correlation coefficient between policy uncertainty and market returns, suggesting that the fluctuations of each variable are greatly influenced by their values in the preceding period. Our analysis highlights the understanding of the dynamical relationship between stock market and fiscal and monetary policy.

  7. The time-varying correlation between policy uncertainty and stock returns: Evidence from China

    Science.gov (United States)

    Xiong, Xiong; Bian, Yuxiang; Shen, Dehua

    2018-06-01

    In this paper, we use a new policy uncertainty index to investigate the time-varying correlation between economic policy uncertainty (EPU) and Chinese stock market returns. The correlation is examined in the period from January 1995 to December 2016. We show that absolute changes in EPU have a significant impact on stock market returns. Specifically, empirical results based on the DCC-GARCH model reveal that the correlation between EPU and stock returns has large fluctuations, especially during a financial crisis; in addition, the impact of EPU on the Shanghai stock market is greater than on the Shenzhen stock market. Robustness results reveal that the impact of EPU on state-owned enterprises is larger than on non-state enterprises. All of these results highlight the important role of EPU in the Chinese stock market, and shed light on such issues for future research.

  8. One hundred years of return period: Strengths and limitations

    Science.gov (United States)

    Volpi, E.; Fiori, A.; Grimaldi, S.; Lombardo, F.; Koutsoyiannis, D.

    2015-10-01

    One hundred years from its original definition by Fuller, the probabilistic concept of return period is widely used in hydrology as well as in other disciplines of geosciences to give an indication on critical event rareness. This concept gains its popularity, especially in engineering practice for design and risk assessment, due to its ease of use and understanding; however, return period relies on some basic assumptions that should be satisfied for a correct application of this statistical tool. Indeed, conventional frequency analysis in hydrology is performed by assuming as necessary conditions that extreme events arise from a stationary distribution and are independent of one another. The main objective of this paper is to investigate the properties of return period when the independence condition is omitted; hence, we explore how the different definitions of return period available in literature affect results of frequency analysis for processes correlated in time. We demonstrate that, for stationary processes, the independence condition is not necessary in order to apply the classical equation of return period (i.e., the inverse of exceedance probability). On the other hand, we show that the time-correlation structure of hydrological processes modifies the shape of the distribution function of which the return period represents the first moment. This implies that, in the context of time-dependent processes, the return period might not represent an exhaustive measure of the probability of failure, and that its blind application could lead to misleading results. To overcome this problem, we introduce the concept of Equivalent Return Period, which controls the probability of failure still preserving the virtue of effectively communicating the event rareness.

  9. On the return period and design in a multivariate framework

    Directory of Open Access Journals (Sweden)

    G. Salvadori

    2011-11-01

    Full Text Available Calculating return periods and design quantiles in a multivariate environment is a difficult problem: this paper tries to make the issue clear. First, we outline a possible way to introduce a consistent theoretical framework for the calculation of the return period in a multi-dimensional environment, based on Copulas and the Kendall's measure. Secondly, we introduce several approaches for the identification of suitable design events: these latter quantities are of utmost importance in practical applications, but their calculation is yet limited, due to the lack of an adequate theoretical environment where to embed the problem. Throughout the paper, a case study involving the behavior of a dam is used to illustrate the new concepts outlined in this work.

  10. Importance of historical seismicity in the evaluation of large return period hazards

    International Nuclear Information System (INIS)

    Oliveira, C.S.

    1983-01-01

    This paper reports the results from an historical investigation on earthquake activity in Portugal based on data collected from original sources. A detailed revision of earthquake catalogues in what concerns date of occurrence, isosseismal maps, epicentral location, magnitude and duration of vibration was made for most of the 260 events identified in the period 1000 to 1900. Introducing this new piece of information which exhibits a much higher degree of quality into standard hazard models, uncertainties on final estimates for the zones of large return periods, RP, (RP > 200 years) are greatly reduced

  11. Estimation of return levels against different return periods of extreme annual rainfall over Baluchistan

    International Nuclear Information System (INIS)

    Ali, M.; Jan, B.; Iqbal, J.

    2012-01-01

    Unprecedented heavy monsoon rainfall began in the last week of July 2010 in the Northern part of our country, causes floods in Baluchistan and Sindh. As the high frequency rainfall events are a significant cause of current severe flooding in Pakistan and any fluctuation in the level of such events may cause huge economic losses as well as social problem, urban structures (i.e. dams, urban drainage systems and flood). Statistical distributions are used to identify extremes of annual rainfall of different cities of Baluchistan (Quetta, Sibbi, Khuzdar, Lasbella, Dalbandin and Pasni) with their return periods. Analysis predicts that Gumbel Max. (GM) Distribution is the best fitted distribution for Sibbi and Lasbella while the GEV distribution is the best fitted for Quetta, Khuzdar, Dalbandin and Pasni. The analysis also suggests that different cities of Baluchistan have 30-years return period for getting more than 90 mm average daily rainfall while they have 100-years return period for receiving more than 118 mm daily rainfall. This suggests for suitable flood forecasting and improving the river structure in Baluchistan, Pakistan. (author)

  12. A Bivariate return period for levee failure monitoring

    Science.gov (United States)

    Isola, M.; Caporali, E.

    2017-12-01

    Levee breaches are strongly linked with the interaction processes among water, soil and structure, thus many are the factors that affect the breach development. One of the main is the hydraulic load, characterized by intensity and duration, i.e. by the flood event hydrograph. On the magnitude of the hydraulic load is based the levee design, generally without considering the fatigue failure due to the load duration. Moreover, many are the cases in which the levee breach are characterized by flood of magnitude lower than the design one. In order to implement the strategies of flood risk management, we built here a procedure based on a multivariate statistical analysis of flood peak and volume together with the analysis of the past levee failure events. Particularly, in order to define the probability of occurrence of the hydraulic load on a levee, a bivariate copula model is used to obtain the bivariate joint distribution of flood peak and volume. Flood peak is the expression of the load magnitude, while the volume is the expression of the stress over time. We consider the annual flood peak and the relative volume. The volume is given by the hydrograph area between the beginning and the end of event. The beginning of the event is identified as an abrupt rise of the discharge by more than 20%. The end is identified as the point from which the receding limb is characterized by the baseflow, using a nonlinear reservoir algorithm as baseflow separation technique. By this, with the aim to define warning thresholds we consider the past levee failure events and the relative bivariate return period (BTr) compared with the estimation of a traditional univariate model. The discharge data of 30 hydrometric stations of Arno River in Tuscany, Italy, in the period 1995-2016 are analysed. The database of levee failure events, considering for each event the location as well as the failure mode, is also created. The events were registered in the period 2000-2014 by EEA

  13. Economic policy uncertainty and housing returns in Germany: Evidence from a bootstrap rolling window

    Directory of Open Access Journals (Sweden)

    David Su

    2016-06-01

    Full Text Available The purpose of this investigation is to research the causal link between economic policy uncertainty (EPU and the housing returns (HR in Germany. In the estimated vector autoregressive models, we test its stability and find the short-run relationship between HR and EPU is unstable. As a result, a time-varying approach (bootstrap rolling window causality test is utilized to revisit the dynamic causal link, and we find EPU has no impact on HR due to the stability of the real estate market in Germany. HR does not have significant effects on EPU in most time periods. However, significant feedback in several sub-periods (both positive and negative are found from HR to EPU, which indicates the causal link from HR to EPU varies over time. The empirical results do not support the general equilibrium model of government policy choices that indicate EPU does not play a role in the real estate market. The basic conclusion is that the real estate market shows its stability due to the social welfare nature and the rational institutional arrangement of the real estate in Germany, and the real estate market also shows its importance that it has significant effect on the economic policy choice in some periods when negative external shocks occur.

  14. The return period analysis of natural disasters with statistical modeling of bivariate joint probability distribution.

    Science.gov (United States)

    Li, Ning; Liu, Xueqin; Xie, Wei; Wu, Jidong; Zhang, Peng

    2013-01-01

    New features of natural disasters have been observed over the last several years. The factors that influence the disasters' formation mechanisms, regularity of occurrence and main characteristics have been revealed to be more complicated and diverse in nature than previously thought. As the uncertainty involved increases, the variables need to be examined further. This article discusses the importance and the shortage of multivariate analysis of natural disasters and presents a method to estimate the joint probability of the return periods and perform a risk analysis. Severe dust storms from 1990 to 2008 in Inner Mongolia were used as a case study to test this new methodology, as they are normal and recurring climatic phenomena on Earth. Based on the 79 investigated events and according to the dust storm definition with bivariate, the joint probability distribution of severe dust storms was established using the observed data of maximum wind speed and duration. The joint return periods of severe dust storms were calculated, and the relevant risk was analyzed according to the joint probability. The copula function is able to simulate severe dust storm disasters accurately. The joint return periods generated are closer to those observed in reality than the univariate return periods and thus have more value in severe dust storm disaster mitigation, strategy making, program design, and improvement of risk management. This research may prove useful in risk-based decision making. The exploration of multivariate analysis methods can also lay the foundation for further applications in natural disaster risk analysis. © 2012 Society for Risk Analysis.

  15. Return handling options and order quantities for single period products

    NARCIS (Netherlands)

    D. Vlachos (Dimitrios); R. Dekker (Rommert)

    2000-01-01

    textabstractProducts which are sold through E-commerce or mail sales catalogues tend to have a much higher return rate than traditional products. The returns are especially problematic for seasonal products. To support decision making in these situations we study various options, which may be

  16. Multivariate return periods of sea storms for coastal erosion risk assessment

    Directory of Open Access Journals (Sweden)

    S. Corbella

    2012-08-01

    Full Text Available The erosion of a beach depends on various storm characteristics. Ideally, the risk associated with a storm would be described by a single multivariate return period that is also representative of the erosion risk, i.e. a 100 yr multivariate storm return period would cause a 100 yr erosion return period. Unfortunately, a specific probability level may be associated with numerous combinations of storm characteristics. These combinations, despite having the same multivariate probability, may cause very different erosion outcomes. This paper explores this ambiguity problem in the context of copula based multivariate return periods and using a case study at Durban on the east coast of South Africa. Simulations were used to correlate multivariate return periods of historical events to return periods of estimated storm induced erosion volumes. In addition, the relationship of the most-likely design event (Salvadori et al., 2011 to coastal erosion was investigated. It was found that the multivariate return periods for wave height and duration had the highest correlation to erosion return periods. The most-likely design event was found to be an inadequate design method in its current form. We explore the inclusion of conditions based on the physical realizability of wave events and the use of multivariate linear regression to relate storm parameters to erosion computed from a process based model. Establishing a link between storm statistics and erosion consequences can resolve the ambiguity between multivariate storm return periods and associated erosion return periods.

  17. Holding Period Return-Risk Modeling: The Importance of Dividends

    NARCIS (Netherlands)

    W.G.P.M. Hallerbach (Winfried)

    2003-01-01

    textabstractIn this paper we explore the relevance of dividends in the total equity return over longer time horizons. In addition, we investigate the effects of different reinvestment assumptions of dividends. We use a unique set of revised and corrected US equity data series, comprising monthly

  18. Variation of Time Domain Failure Probabilities of Jack-up with Wave Return Periods

    Science.gov (United States)

    Idris, Ahmad; Harahap, Indra S. H.; Ali, Montassir Osman Ahmed

    2018-04-01

    This study evaluated failure probabilities of jack up units on the framework of time dependent reliability analysis using uncertainty from different sea states representing different return period of the design wave. Surface elevation for each sea state was represented by Karhunen-Loeve expansion method using the eigenfunctions of prolate spheroidal wave functions in order to obtain the wave load. The stochastic wave load was propagated on a simplified jack up model developed in commercial software to obtain the structural response due to the wave loading. Analysis of the stochastic response to determine the failure probability in excessive deck displacement in the framework of time dependent reliability analysis was performed by developing Matlab codes in a personal computer. Results from the study indicated that the failure probability increases with increase in the severity of the sea state representing a longer return period. Although the results obtained are in agreement with the results of a study of similar jack up model using time independent method at higher values of maximum allowable deck displacement, it is in contrast at lower values of the criteria where the study reported that failure probability decreases with increase in the severity of the sea state.

  19. Challenges estimating the return period of extreme floods for reinsurance applications

    Science.gov (United States)

    Raven, Emma; Busby, Kathryn; Liu, Ye

    2013-04-01

    individual extreme events. Since the predicted loss estimates, typically in the form of a curve plotting return period against modelled loss, are used in the pricing of reinsurance, we demonstrate the importance of the estimated return period and understanding the uncertainties associated with it.

  20. The Uncertainty of Biomass Estimates from Modeled ICESat-2 Returns Across a Boreal Forest Gradient

    Science.gov (United States)

    Montesano, P. M.; Rosette, J.; Sun, G.; North, P.; Nelson, R. F.; Dubayah, R. O.; Ranson, K. J.; Kharuk, V.

    2014-01-01

    The Forest Light (FLIGHT) radiative transfer model was used to examine the uncertainty of vegetation structure measurements from NASA's planned ICESat-2 photon counting light detection and ranging (LiDAR) instrument across a synthetic Larix forest gradient in the taiga-tundra ecotone. The simulations demonstrate how measurements from the planned spaceborne mission, which differ from those of previous LiDAR systems, may perform across a boreal forest to non-forest structure gradient in globally important ecological region of northern Siberia. We used a modified version of FLIGHT to simulate the acquisition parameters of ICESat-2. Modeled returns were analyzed from collections of sequential footprints along LiDAR tracks (link-scales) of lengths ranging from 20 m-90 m. These link-scales traversed synthetic forest stands that were initialized with parameters drawn from field surveys in Siberian Larix forests. LiDAR returns from vegetation were compiled for 100 simulated LiDAR collections for each 10 Mg · ha(exp -1) interval in the 0-100 Mg · ha(exp -1) above-ground biomass density (AGB) forest gradient. Canopy height metrics were computed and AGB was inferred from empirical models. The root mean square error (RMSE) and RMSE uncertainty associated with the distribution of inferred AGB within each AGB interval across the gradient was examined. Simulation results of the bright daylight and low vegetation reflectivity conditions for collecting photon counting LiDAR with no topographic relief show that 1-2 photons are returned for 79%-88% of LiDAR shots. Signal photons account for approximately 67% of all LiDAR returns, while approximately 50% of shots result in 1 signal photon returned. The proportion of these signal photon returns do not differ significantly (p greater than 0.05) for AGB intervals greater than 20 Mg · ha(exp -1). The 50m link-scale approximates the finest horizontal resolution (length) at which photon counting LiDAR collection provides strong model

  1. Return period assessment of urban pluvial floods through modelling of rainfall–flood response

    DEFF Research Database (Denmark)

    Tuyls, Damian Murla; Thorndahl, Søren Liedtke; Rasmussen, Michael Robdrup

    2018-01-01

    Intense rainfall in urban areas can often generate severe flood impacts. Consequently, it is crucial to design systems to minimize potential flood damages. Traditional, simple design of urban drainage systems assumes agreement between rainfall return period and its consequent flood return period......; however, this does not always apply. Hydraulic infrastructures found in urban drainage systems can increase system heterogeneity and perturb the impact of severe rainfall response. In this study, a surface flood return period assessment was carried out at Lystrup (Denmark), which has received the impact...... of flooding in recent years. A 35 years' rainfall dataset together with a coupled 1D/2D surface and network model was used to analyse and assess flood return period response. Results show an ambiguous relation between rainfall and flood return periods indicating that linear rainfall–runoff relationships will...

  2. Multi-Period Mean-Variance Portfolio Selection with Uncertain Time Horizon When Returns Are Serially Correlated

    Directory of Open Access Journals (Sweden)

    Ling Zhang

    2012-01-01

    Full Text Available We study a multi-period mean-variance portfolio selection problem with an uncertain time horizon and serial correlations. Firstly, we embed the nonseparable multi-period optimization problem into a separable quadratic optimization problem with uncertain exit time by employing the embedding technique of Li and Ng (2000. Then we convert the later into an optimization problem with deterministic exit time. Finally, using the dynamic programming approach, we explicitly derive the optimal strategy and the efficient frontier for the dynamic mean-variance optimization problem. A numerical example with AR(1 return process is also presented, which shows that both the uncertainty of exit time and the serial correlations of returns have significant impacts on the optimal strategy and the efficient frontier.

  3. Supporting a Deep Space Gateway with Free-Return Earth-Moon Periodic Orbits

    Science.gov (United States)

    Genova, A. L.; Dunham, D. W.; Hardgrove, C.

    2018-02-01

    Earth-Moon periodic orbits travel between the Earth and Moon via free-return circumlunar segments and can host a station that can provide architecture support to other nodes near the Moon and Mars while enabling science return from cislunar space.

  4. Stormwater Design Return Period Standards for U.S. Transportation Infrastructure: How Are States Approaching Resilience?

    Science.gov (United States)

    Samaras, C.; Lopez, T.

    2016-12-01

    Climate change is projected to increase the frequency and intensity of precipitation in many regions, which is relevant for stormwater engineering designs and resilience in the transportation sector. Existing and future stormwater infrastructure is generally designed for historical and stationary hydrologic conditions. For example, the design return period is based on statistical analysis of past precipitation events, often over a 50-year historical timeline. The design return period translates into how much peak precipitation volume a system is designed for in a state, and provides information about the performance of a drainage structure. The higher the design period used by an engineer for a given stormwater system, the more peak stormwater volume the system can convey. Therefore, design return periods can be associated with a design's near-term and long-term resilience. However, there is a tradeoff between the choice of design return period, the total infrastructure capital cost, and the resilience of a system to heavy precipitation events. This study analyzes current stormwater infrastructure design guidelines for state departments of transportation in the contiguous United States, in order to understand how stormwater design return periods vary across states and provide insight into the resilience of current stormwater systems design. The study found that the design return period varies considerably across the United States by roadway functional class and drainage classification, as well as within climate regions. Understanding this variation will help states identify possible vulnerabilities, highlight deficiencies across states and infrastructure types, and help in updating design return periods to increase the climate resilience of stormwater infrastructure.

  5. Business Return in New Orleans: Decision Making Amid Post-Katrina Uncertainty

    Science.gov (United States)

    Lam, Nina S. N.; Pace, Kelley; Campanella, Richard; LeSage, James; Arenas, Helbert

    2009-01-01

    Background Empirical observations on how businesses respond after a major catastrophe are rare, especially for a catastrophe as great as Hurricane Katrina, which hit New Orleans, Louisiana on August 29, 2005. We analyzed repeated telephone surveys of New Orleans businesses conducted in December 2005, June 2006, and October 2007 to understand factors that influenced decisions to re-open amid post-disaster uncertainty. Methodology/Principal Findings Businesses in the group of professional, scientific, and technical services reopened the fastest in the near term, but differences in the rate of reopening for businesses stratified by type became indistinguishable in the longer term (around two years later). A reopening rate of 65% was found for all businesses by October 2007. Discriminant analysis showed significant differences in responses reflecting their attitudes about important factors between businesses that reopened and those that did not. Businesses that remained closed at the time of our third survey (two years after Katrina) ranked levee protection as the top concern immediately after Katrina, but damage to their premises and financing became major concerns in subsequent months reflected in the later surveys. For businesses that had opened (at the time of our third survey), infrastructure protection including levee, utility, and communications were the main concerns mentioned in surveys up to the third survey, when the issue of crime became their top concern. Conclusions/Significance These findings underscore the need to have public policy and emergency plans in place prior to the actual disaster, such as infrastructure protection, so that the policy can be applied in a timely manner before business decisions to return or close are made. Our survey results, which include responses from both open and closed businesses, overcome the “survivorship bias” problem and provide empirical observations that should be useful to improve micro-level spatial economic

  6. Business return in New Orleans: decision making amid post-Katrina uncertainty.

    Directory of Open Access Journals (Sweden)

    Nina S N Lam

    Full Text Available BACKGROUND: Empirical observations on how businesses respond after a major catastrophe are rare, especially for a catastrophe as great as Hurricane Katrina, which hit New Orleans, Louisiana on August 29, 2005. We analyzed repeated telephone surveys of New Orleans businesses conducted in December 2005, June 2006, and October 2007 to understand factors that influenced decisions to re-open amid post-disaster uncertainty. METHODOLOGY/PRINCIPAL FINDINGS: Businesses in the group of professional, scientific, and technical services reopened the fastest in the near term, but differences in the rate of reopening for businesses stratified by type became indistinguishable in the longer term (around two years later. A reopening rate of 65% was found for all businesses by October 2007. Discriminant analysis showed significant differences in responses reflecting their attitudes about important factors between businesses that reopened and those that did not. Businesses that remained closed at the time of our third survey (two years after Katrina ranked levee protection as the top concern immediately after Katrina, but damage to their premises and financing became major concerns in subsequent months reflected in the later surveys. For businesses that had opened (at the time of our third survey, infrastructure protection including levee, utility, and communications were the main concerns mentioned in surveys up to the third survey, when the issue of crime became their top concern. CONCLUSIONS/SIGNIFICANCE: These findings underscore the need to have public policy and emergency plans in place prior to the actual disaster, such as infrastructure protection, so that the policy can be applied in a timely manner before business decisions to return or close are made. Our survey results, which include responses from both open and closed businesses, overcome the "survivorship bias" problem and provide empirical observations that should be useful to improve micro

  7. How are flood risk estimates affected by the choice of return-periods?

    Science.gov (United States)

    Ward, P. J.; de Moel, H.; Aerts, J. C. J. H.

    2011-12-01

    Flood management is more and more adopting a risk based approach, whereby flood risk is the product of the probability and consequences of flooding. One of the most common approaches in flood risk assessment is to estimate the damage that would occur for floods of several exceedance probabilities (or return periods), to plot these on an exceedance probability-loss curve (risk curve) and to estimate risk as the area under the curve. However, there is little insight into how the selection of the return-periods (which ones and how many) used to calculate risk actually affects the final risk calculation. To gain such insights, we developed and validated an inundation model capable of rapidly simulating inundation extent and depth, and dynamically coupled this to an existing damage model. The method was applied to a section of the River Meuse in the southeast of the Netherlands. Firstly, we estimated risk based on a risk curve using yearly return periods from 2 to 10 000 yr (€ 34 million p.a.). We found that the overall risk is greatly affected by the number of return periods used to construct the risk curve, with over-estimations of annual risk between 33% and 100% when only three return periods are used. In addition, binary assumptions on dike failure can have a large effect (a factor two difference) on risk estimates. Also, the minimum and maximum return period considered in the curve affects the risk estimate considerably. The results suggest that more research is needed to develop relatively simple inundation models that can be used to produce large numbers of inundation maps, complementary to more complex 2-D-3-D hydrodynamic models. It also suggests that research into flood risk could benefit by paying more attention to the damage caused by relatively high probability floods.

  8. PORTOFOLIO MARKOWITZ: UJI OPTIMAL HOLDING PERIOD DAN KINERJA PORTOFOLIO BERDASARKAN KRITERIA RISIKO DAN TARGET RETURN

    Directory of Open Access Journals (Sweden)

    Andi Ivand Markemo Boangmanalu

    2017-04-01

    Full Text Available The concept of mean-variance optimization, developed by Markowitz, is the cornerstone of modern finance theory. The objective of this portfolio construction is to minimize investment risk by forming optimal portfolios. Dynamic movement in capital markets requires not only changes in portfolio composition. Optimal portfolio is not only determined by the covariance between securities in the portfolio, but also by holding period. The aims of this study is to answer two research questions. The first research question is how long the optimal holding period that was resulted from trade-off between risk and return. This study using target return that are determined hypothetically as well as the risk criteria are divided into 3 namely the mean variance, semivarians and expected loss. Target returns are simulated in this study were divided into 3 criteria namely aggressive, moderate and conservative. The second research question is whether there are differences among the various portfolio performance based on criteria of risk and target return. Portfolio performance is measured by using excess return and the Sharpe index. In this study, stocks covered in LQ-45 index are used to construct efficient portoflio. Monthly price series for company and LQ-45 index for February 2004 to September 2008 are collected. The analysis found that optimal holing period is ranges between 1-5 months. Holding period of a portfolio that more than 5 months will provide risk and return trade-off less favorable. In addition this study found that there was no significant differences in portfolio performance based on overall scenarios

  9. Behavior of Stock Price Variability over Trading and Nontrading Periods, and Daily Return Volatility

    Directory of Open Access Journals (Sweden)

    Sumiyana Sumiyana

    2007-09-01

    This study concludes that return variance over trading and nontrading periods, along with overnight and lunch break nontrading session, and the first and second trading session, has differed significantly. In addition, daily return volatility is also not identical significantly. Subsequently, this study used size, trading volume, bid-ask spreads and up-down market as control variables. This study contradicts to all prior studies. This study especially suggests contra evidence in comparisons with previous concepts and theories in regards to size, trading volume, bid-ask spreads, and up-down market as control variables.

  10. Bivariate return periods of temperature and precipitation explain a large fraction of European crop yields

    Science.gov (United States)

    Zscheischler, Jakob; Orth, Rene; Seneviratne, Sonia I.

    2017-07-01

    Crops are vital for human society. Crop yields vary with climate and it is important to understand how climate and crop yields are linked to ensure future food security. Temperature and precipitation are among the key driving factors of crop yield variability. Previous studies have investigated mostly linear relationships between temperature and precipitation and crop yield variability. Other research has highlighted the adverse impacts of climate extremes, such as drought and heat waves, on crop yields. Impacts are, however, often non-linearly related to multivariate climate conditions. Here we derive bivariate return periods of climate conditions as indicators for climate variability along different temperature-precipitation gradients. We show that in Europe, linear models based on bivariate return periods of specific climate conditions explain on average significantly more crop yield variability (42 %) than models relying directly on temperature and precipitation as predictors (36 %). Our results demonstrate that most often crop yields increase along a gradient from hot and dry to cold and wet conditions, with lower yields associated with hot and dry periods. The majority of crops are most sensitive to climate conditions in summer and to maximum temperatures. The use of bivariate return periods allows the integration of non-linear impacts into climate-crop yield analysis. This offers new avenues to study the link between climate and crop yield variability and suggests that they are possibly more strongly related than what is inferred from conventional linear models.

  11. Spatial variability of maximum annual daily rain under different return periods at the Rio de Janeiro state, Brazil

    Directory of Open Access Journals (Sweden)

    Roriz Luciano Machado

    2010-01-01

    Full Text Available Knowledge of maximum daily rain and its return period in a region is an important tool to soil conservation, hydraulic engineering and preservation of road projects. The objective of this work was to evaluate the spatial variability of maximum annual daily rain considering different return periods, at the Rio de Janeiro State. The data set was composed by historical series of 119 rain gauges, for 36 years of observation. The return periods, estimated by Gumbel distribution, were 2, 5, 10, 25, 50 and 100 years. The spatial variability of the return periods was evaluated by semivariograms. All the return periods presented spatial dependence, with exponential and spherical model fitted to the experimental semivariograms. The parameters of the fitted semivariogram model were very similar; however, it was observed the presence of higher nugget effects for semivariograms of longer return periods. The values of maximum annual daily average rain in all the return periods increased from north to south and from countryside to the coast. In the region between the Serra do Mar range and the coast, besides increasing in magnitude, an increase in the spatial variability of the studied values with increasing return periods was also noticed. This behavior is probably caused by the orographic effect. The interpolated maps were more erratic for higher return periods and at the North, Northeast and Coastal Plain regions, in which the installation of new pluviometric stations are recommended.

  12. Coordinating a Supply Chain with Risk-Averse Agents under Demand and Consumer Returns Uncertainty

    Directory of Open Access Journals (Sweden)

    Jian Liu

    2013-01-01

    Full Text Available This paper examines the optimal order decision in a supply chain when it faces uncertain demand and uncertain consumer returns. We build consumer returns model with decision-makers’ risk preference under mean-variance objective framework and discuss supply chain coordination problem under wholesale-price-only policy and the manufacturer’s buyback policy, respectively. We find that, with wholesale price policy, the supply chain cannot be coordinated whether the supply chain agents are risk-neutral or risk-averse. However, with buyback policy, the supply chain can be coordinated and the profit of the supply chain can be arbitrarily allocated between the manufacturer and the retailer. Through numerical examples, we illustrate the impact of stochastic consumer returns and the supply chain agents’ risk attitude on the optimal order decision.

  13. Multivariate return periods in hydrology: a critical and practical review focusing on synthetic design hydrograph estimation

    Directory of Open Access Journals (Sweden)

    B. Gräler

    2013-04-01

    Full Text Available Most of the hydrological and hydraulic studies refer to the notion of a return period to quantify design variables. When dealing with multiple design variables, the well-known univariate statistical analysis is no longer satisfactory, and several issues challenge the practitioner. How should one incorporate the dependence between variables? How should a multivariate return period be defined and applied in order to yield a proper design event? In this study an overview of the state of the art for estimating multivariate design events is given and the different approaches are compared. The construction of multivariate distribution functions is done through the use of copulas, given their practicality in multivariate frequency analyses and their ability to model numerous types of dependence structures in a flexible way. A synthetic case study is used to generate a large data set of simulated discharges that is used for illustrating the effect of different modelling choices on the design events. Based on different uni- and multivariate approaches, the design hydrograph characteristics of a 3-D phenomenon composed of annual maximum peak discharge, its volume, and duration are derived. These approaches are based on regression analysis, bivariate conditional distributions, bivariate joint distributions and Kendall distribution functions, highlighting theoretical and practical issues of multivariate frequency analysis. Also an ensemble-based approach is presented. For a given design return period, the approach chosen clearly affects the calculated design event, and much attention should be given to the choice of the approach used as this depends on the real-world problem at hand.

  14. ICUD-0147 Extreme event statistics of urban pluvial floods – Return period assessment and rainfall variability impacts

    DEFF Research Database (Denmark)

    Tuyls, Damian Murla; Nielsen, Rasmus; Thorndahl, Søren Liedtke

    2017-01-01

    A return period assessment of urban flood has been performed and its adhered impact of rainfall variability studied over a urban drainage catchment area in Aalborg, Denmark. Recorded rainfall from 7 rain gauges has been used, located in a range of 7.5Km and for a period varying form 18-37 years....... Return period of rainfall and flood at catchment and local scale has been estimated, its derived ambiguities analysed and the variability of rain gauge based rainfall investigated regarding to flood estimation results. Results show a clear contrast between rainfall and flood return period estimates...

  15. The Conceptual Model of Calculating the Return Period of the Costs for Creation of the Enterprise’s Economic Security Service in the Short-Term Period

    Directory of Open Access Journals (Sweden)

    Melikhova Tetiana O.

    2018-03-01

    Full Text Available Determination of the return period of the costs, advanced for the creation of economic security service of enterprise during a year, involves consideration of interaction of the conditional money flow, accumulated for a certain number of months, and the constant costs. The main component of the constant costs are the annual depreciation deductions. The return period is considered as gross, net, valid, and specified. The gross (net, valid, and specified return period is the time, wherein the gross conditional money flow, equal to the advanced costs, will be accumulated. The gross return period, taking account of the effect of time factor, is proposed to be defined as the ratio of annual depreciation deductions increased by the annual compounding coefficient to the conditional average monthly gross money flow, increased by the average monthly inflation index. As for the short-term period, a relationship between the gross, net, valid, and specified return periods of the costs, advanced to the creation of the economic security service, has been identified. The net (valid, specified return period is equal to the gross period adjusted to the coefficient of excess of the gross conditional money flow, accumulated in the gross period, over the net (valid, specified conditional cash flow.

  16. Studies of phase return map and symbolic dynamics in a periodically driven Hodgkin—Huxley neuron

    International Nuclear Information System (INIS)

    Ding Jiong; Zhang Hong; Tong Qin-Ye; Chen Zhuo

    2014-01-01

    How neuronal spike trains encode external information is a hot topic in neurodynamics studies. In this paper, we investigate the dynamical states of the Hodgkin—Huxley neuron under periodic forcing. Depending on the parameters of the stimulus, the neuron exhibits periodic, quasiperiodic and chaotic spike trains. In order to analyze these spike trains quantitatively, we use the phase return map to describe the dynamical behavior on a one-dimensional (1D) map. According to the monotonicity or discontinuous point of the 1D map, the spike trains are transformed into symbolic sequences by implementing a coarse-grained algorithm — symbolic dynamics. Based on the ordering rules of symbolic dynamics, the parameters of the external stimulus can be measured in high resolution with finite length symbolic sequences. A reasonable explanation for why the nervous system can discriminate or cognize the small change of the external signals in a short time is also presented. (general)

  17. Estimating of seismic return periods in Laguna Verde Nuclear Power Plant

    International Nuclear Information System (INIS)

    Flores R, J.H.

    1993-01-01

    The study of seismic risk in the site of Laguna Verde Nuclear Power Plant and surroundings was made considering the different periods of seismic return and the probability of occurrence in distinct time intervals (50, 75, 100, 125, 150 years) starting with the distribution of first type of extreme values of Gumbel (G1), the value used for the assessment of lifetime of lump was 50 years, and the rest of the periods are used to evaluate temporary nuclear cemeteries, it is to say for reducing the radioactivity of burned fuel assemblies. The seismic data belongs to the seismicity catalog (1920-1982) elaborated around the site, which average magnitude was 5 in the Richter Scale and are considered as shallow and are located in the Continental crust of North American shelf, and are induced by the pressure of the cocos shelf, being 36 % of the seismic movements of intermediate value and two seismic movements of deep value. (Author)

  18. Return Period of a Sea Storm with at Least Two Waves Higher than a Fixed Threshold

    Directory of Open Access Journals (Sweden)

    Felice Arena

    2013-01-01

    Full Text Available Practical applications in ocean engineering require the long-term analysis for prediction of extreme waves, that identify design conditions. If extreme individual waves are investigated, we need to combine long-term statistical analysis of ocean waves with short-term statistics. The former considers the distribution of standard deviation of free surface displacement in the considered location in a long-time span, of order of 10 years or more. The latter analyzes the distribution of individual wave heights in a sea state, which is a Gaussian process in time domain. Recent advanced approaches enable the combination of the two analyses. In the paper the analytical solution is obtained for the return period of a sea storm with at least two individual waves higher than a fixed level. This solution is based on the application of the Equivalent Triangular Storm model for the representation of actual storms. One of the corollaries of the solution gives the exact expression for the probability that at least two waves higher than fixed level are produced during the lifetime of a structure. The previous solution of return period and the relative probability of exceedance may be effectively applied for the risk analysis of ocean structures.

  19. Levee reliability analyses for various flood return periods - a case study in southern Taiwan

    Science.gov (United States)

    Huang, W.-C.; Yu, H.-W.; Weng, M.-C.

    2015-04-01

    In recent years, heavy rainfall conditions have caused disasters around the world. To prevent losses by floods, levees have often been constructed in inundation-prone areas. This study performed reliability analyses for the Chiuliao First Levee in southern Taiwan. The failure-related parameters were the water level, the scouring depth, and the in situ friction angle. Three major failure mechanisms were considered: the slope sliding failure of the levee and the sliding and overturning failures of the retaining wall. When the variability of the in situ friction angle and the scouring depth are considered for various flood return periods, the variations of the factor of safety for the different failure mechanisms show that the retaining wall sliding and overturning failures are more sensitive to the change of the friction angle. When the flood return period is greater than 2 years, the levee could fail with slope sliding for all values of the water level difference. The results of levee stability analysis considering the variability of different parameters could aid engineers in designing the levee cross sections, especially with potential failure mechanisms in mind.

  20. 26 CFR 1.6038-1 - Information returns required of domestic corporations with respect to annual accounting periods...

    Science.gov (United States)

    2010-04-01

    ... the annual accounting period; (6) A list showing the name and address of, and the number of shares of... paragraphs (e) and (f) of this section shall be expressed in United States currency with a statement of the exchange rates used. (h) Time and place for filing return. Returns on Form 2952 required under paragraph (a...

  1. Return periods of losses associated with European windstorm series in a changing climate

    International Nuclear Information System (INIS)

    Karremann, Melanie K; Pinto, Joaquim G; Reyers, Mark; Klawa, Matthias

    2014-01-01

    Possible future changes of clustering and return periods (RPs) of European storm series with high potential losses are quantified. Historical storm series are identified using 40 winters of reanalysis. Time series of top events (1, 2 or 5 year return levels (RLs)) are used to assess RPs of storm series both empirically and theoretically. Additionally, 800 winters of general circulation model simulations for present (1960–2000) and future (2060–2100) climate conditions are investigated. Clustering is identified for most countries, and estimated RPs are similar for reanalysis and present day simulations. Future changes of RPs are estimated for fixed RLs and fixed loss index thresholds. For the former, shorter RPs are found for Western Europe, but changes are small and spatially heterogeneous. For the latter, which combines the effects of clustering and event ranking shifts, shorter RPs are found everywhere except for Mediterranean countries. These changes are generally not statistically significant between recent and future climate. However, the RPs for the fixed loss index approach are mostly beyond the range of pre-industrial natural climate variability. This is not true for fixed RLs. The quantification of losses associated with storm series permits a more adequate windstorm risk assessment in a changing climate. (letter)

  2. Physical insight into the thermodynamic uncertainty relation using Brownian motion in tilted periodic potentials

    Science.gov (United States)

    Hyeon, Changbong; Hwang, Wonseok

    2017-07-01

    Using Brownian motion in periodic potentials V (x ) tilted by a force f , we provide physical insight into the thermodynamic uncertainty relation, a recently conjectured principle for statistical errors and irreversible heat dissipation in nonequilibrium steady states. According to the relation, nonequilibrium output generated from dissipative processes necessarily incurs an energetic cost or heat dissipation q , and in order to limit the output fluctuation within a relative uncertainty ɛ , at least 2 kBT /ɛ2 of heat must be dissipated. Our model shows that this bound is attained not only at near-equilibrium [f ≪V'(x ) ] but also at far-from-equilibrium [f ≫V'(x ) ] , more generally when the dissipated heat is normally distributed. Furthermore, the energetic cost is maximized near the critical force when the barrier separating the potential wells is about to vanish and the fluctuation of Brownian particles is maximized. These findings indicate that the deviation of heat distribution from Gaussianity gives rise to the inequality of the uncertainty relation, further clarifying the meaning of the uncertainty relation. Our derivation of the uncertainty relation also recognizes a bound of nonequilibrium fluctuations that the variance of dissipated heat (σq2) increases with its mean (μq), and it cannot be smaller than 2 kBT μq .

  3. The joint return period analysis of natural disasters based on monitoring and statistical modeling of multidimensional hazard factors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xueqin [State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875 (China); National Marine Environmental Monitoring Center, State Oceanic Administration, Dalian 116023 (China); School of Social Development and Public Policy, Beijing Normal University, Beijing 100875 (China); Li, Ning [State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875 (China); Yuan, Shuai, E-mail: syuan@nmemc.org.cn [National Marine Environmental Monitoring Center, State Oceanic Administration, Dalian 116023 (China); Xu, Ning; Shi, Wenqin; Chen, Weibin [National Marine Environmental Monitoring Center, State Oceanic Administration, Dalian 116023 (China)

    2015-12-15

    As a random event, a natural disaster has the complex occurrence mechanism. The comprehensive analysis of multiple hazard factors is important in disaster risk assessment. In order to improve the accuracy of risk analysis and forecasting, the formation mechanism of a disaster should be considered in the analysis and calculation of multi-factors. Based on the consideration of the importance and deficiencies of multivariate analysis of dust storm disasters, 91 severe dust storm disasters in Inner Mongolia from 1990 to 2013 were selected as study cases in the paper. Main hazard factors from 500-hPa atmospheric circulation system, near-surface meteorological system, and underlying surface conditions were selected to simulate and calculate the multidimensional joint return periods. After comparing the simulation results with actual dust storm events in 54 years, we found that the two-dimensional Frank Copula function showed the better fitting results at the lower tail of hazard factors and that three-dimensional Frank Copula function displayed the better fitting results at the middle and upper tails of hazard factors. However, for dust storm disasters with the short return period, three-dimensional joint return period simulation shows no obvious advantage. If the return period is longer than 10 years, it shows significant advantages in extreme value fitting. Therefore, we suggest the multivariate analysis method may be adopted in forecasting and risk analysis of serious disasters with the longer return period, such as earthquake and tsunami. Furthermore, the exploration of this method laid the foundation for the prediction and warning of other nature disasters. - Highlights: • A method to estimate the multidimensional joint return periods is presented. • 2D function allows better fitting results at the lower tail of hazard factors. • Three-dimensional simulation has obvious advantages in extreme value fitting. • Joint return periods are closer to the reality

  4. The joint return period analysis of natural disasters based on monitoring and statistical modeling of multidimensional hazard factors

    International Nuclear Information System (INIS)

    Liu, Xueqin; Li, Ning; Yuan, Shuai; Xu, Ning; Shi, Wenqin; Chen, Weibin

    2015-01-01

    As a random event, a natural disaster has the complex occurrence mechanism. The comprehensive analysis of multiple hazard factors is important in disaster risk assessment. In order to improve the accuracy of risk analysis and forecasting, the formation mechanism of a disaster should be considered in the analysis and calculation of multi-factors. Based on the consideration of the importance and deficiencies of multivariate analysis of dust storm disasters, 91 severe dust storm disasters in Inner Mongolia from 1990 to 2013 were selected as study cases in the paper. Main hazard factors from 500-hPa atmospheric circulation system, near-surface meteorological system, and underlying surface conditions were selected to simulate and calculate the multidimensional joint return periods. After comparing the simulation results with actual dust storm events in 54 years, we found that the two-dimensional Frank Copula function showed the better fitting results at the lower tail of hazard factors and that three-dimensional Frank Copula function displayed the better fitting results at the middle and upper tails of hazard factors. However, for dust storm disasters with the short return period, three-dimensional joint return period simulation shows no obvious advantage. If the return period is longer than 10 years, it shows significant advantages in extreme value fitting. Therefore, we suggest the multivariate analysis method may be adopted in forecasting and risk analysis of serious disasters with the longer return period, such as earthquake and tsunami. Furthermore, the exploration of this method laid the foundation for the prediction and warning of other nature disasters. - Highlights: • A method to estimate the multidimensional joint return periods is presented. • 2D function allows better fitting results at the lower tail of hazard factors. • Three-dimensional simulation has obvious advantages in extreme value fitting. • Joint return periods are closer to the reality

  5. Urban flood return period assessment through rainfall-flood response modelling

    DEFF Research Database (Denmark)

    Murla, Damian; Thorndahl, Søren Liedtke

    Intense rainfall can often cause severe floods, especially in urbanized areas, where population density or large impermeable areas are found. In this context, floods can generate a direct impact in a social-environmental-economic viewpoint. Traditionally, in design of Urban Drainage Systems (UDS......), correlation between return period (RP) of a given rainfall and RP of its consequent flood has been assumed to be linear (e.g.DS/EN752 (2008)). However, this is not always the case. Complex UDS, where diverse hydraulic infrastructures are often found, increase the heterogeneity of system response, which may...... cause an alteration of the mentioned correlation. Consequently, reliability on future urban planning, design and resilience against floods may be also affected by this misassumption. In this study, an assessment of surface flood RP across rainfall RP has been carried out at Lystrup, a urbanized...

  6. Reducing Uncertainty in Mapping of Mangrove Aboveground Biomass Using Airborne Discrete Return Lidar Data

    Directory of Open Access Journals (Sweden)

    Francisca Rocha de Souza Pereira

    2018-04-01

    Full Text Available Remote sensing techniques offer useful tools for estimating forest biomass to large extent, thereby contributing to the monitoring of land use and landcover dynamics and the effectiveness of environmental policies. The main goal of this study was to investigate the potential use of discrete return light detection and ranging (lidar data to produce accurate aboveground biomass (AGB maps of mangrove forests. AGB was estimated in 34 small plots scatted over a 50 km2 mangrove forest in Rio de Janeiro, Brazil. Plot AGB was computed using either species-specific or non-species-specific allometric models. A total of 26 descriptive lidar metrics were extracted from the normalized height of the lidar point cloud data, and various model forms (random forest and partial least squares regression with backward selection of predictors (Auto-PLS were tested to predict the recorded AGB. The models developed using species-specific allometric models were distinctly more accurate (R2(calibration = 0.89, R2(validation = 0.80, root-mean-square error (RMSE, calibration = 11.20 t·ha−1, and RMSE(validation = 14.80 t·ha−1. The use of non-species-specific allometric models yielded large errors on a landscape scale (+14% or −18% bias depending on the allometry considered, indicating that using poor quality training data not only results in low precision but inaccuracy at all scales. It was concluded that under suitable sampling pattern and provided that accurate field data are used, discrete return lidar can accurately estimate and map the AGB in mangrove forests. Conversely this study underlines the potential bias affecting the estimates of AGB in other forested landscapes where only non-species-specific allometric equations are available.

  7. The dual effect of vegetation green-up date and strong wind on the return period of spring dust storms.

    Science.gov (United States)

    Feng, Jieling; Li, Ning; Zhang, Zhengtao; Chen, Xi

    2017-08-15

    Vegetation phenology changes have been widely applied in the disaster risk assessments of the spring dust storms, and vegetation green-up date shifts have a strong influence on dust storms. However, the effect of earlier vegetation green-up dates due to climate warming on the evaluation of dust storms return periods remains an important, but poorly understood issue. In this study, we evaluate the spring dust storm return period (February to June) in Inner Mongolia, Northern China, using 165 observations of severe spring dust storm events from 16 weather stations, and regional vegetation green-up dates as an integrated factor from NDVI (Normalized Difference Vegetation Index), covering a period from 1982 to 2007, by building the bivariate Copula model. We found that the joint return period showed better fitting results than without considering the integrated factor when the actual dust storm return period is longer than 2years. Also, for extremely severe dust storm events, the gap between simulation result and actual return period can be narrowed up to 0.4888years by using integrated factor. Furthermore, the risk map based on the return period results shows that the Mandula, Zhurihe, Sunitezuoqi, Narenbaolige stations are identified as high risk areas. In this study area, land surface is extensively covered by grasses and shrubs, vegetation green-up date can play a significant role in restraining spring dust storm outbreaks. Therefore, we suggest that Copula method can become a useful tool for joint return period evaluation and risk analysis of severe dust storms. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Estimation of seismic return periods in the Laguna Verde nuclear plant

    International Nuclear Information System (INIS)

    Flores R, J.H.

    1992-01-01

    The study of seismic risk in the area of the Laguna Verde Nucleo electric plant (PNLV) and its surroundings, one carries out estimating the different return periods and the occurrence probability in different intervals of time (5, 75, 100, 125, 150 years starting from the distribution of first type of Gumbel (G1) of extreme values (Burton, 1986), the value that was used to evaluate the useful life of the PNLV was of 50 years, the other periods will be occupy to evaluate 'temporal' nuclear cemeteries, that is to say for diminish the radioactive activity of the fuel assemblies already burned in the reactor pool or in a near place to the place. The seismic data that were used for the analysis were of the seismic catalog that it was elaborated from (1920-1982), around the place whose seismic half magnitude was of 5 grades Richter and a depth 65 km, these earthquakes are classified as shallow earthquakes, which are located in the continental plaque of North-America, these they are induced by the efforts of push of the plaque of Cocos, existing 36% of intermediate and 2 of deep earthquakes. (Author)

  9. Evaluation of the return periods of water crises and evaporation in Monte Cotugno reservoir (Southern Italy)

    Science.gov (United States)

    Copertino, Vito; Lo Vecchio, Giuseppina; Marotta, Lucia; Pastore, Vittoria; Ponzio, Giuseppe; Scavone, Giuseppina; Telesca, Vito; Vita, Michele

    2010-05-01

    In the past water resources management has been dealt and solved increasing water availabilities; today such opportunities have been considerably reduced and the technical-scientific perspectives are addressed above all to improve water system effectiveness and to promote an use of water resources that holds account of the droughts frequency and based on a correct estimate of the hydrologic balance. In this work a study on the water stored in Monte Cotugno reservoir in Sinni river - Basilicata (Southern Italy) - is proposed, estimating water crises return periods and reservoir evaporation. For such purpose the runs method was applied, based on the comparison between the temporal series of the "water volume" hydrological variable and a threshold representative of the "normal" conditions regarding which the availability in excess or defect was estimated. This allowed to individualize the beginning and the end of a water crisis event and to characterize the droughts in terms of duration, sum deficit and intensity. Therefore the return period was evaluated by means of the methodology proposed by Shiau and Shen in 2001, turned out equal approximately to 6 years. Such value was then verified with a frequency analysis of the "water volume" random variable, using the Weibull's distribution. Subsequently, the Fourier's analysis in the last twenty years was carried out, obtaining the same result of the previous methods. Moreover, in proximity of the Monte Cotugno reservoir the weather station of Senise is located, managed by ALSIA (Agenzia Lucana di Sviluppo e Innovazione in Agricultura), that provides in continuous measurements of air temperature and humidity, wind speed and direction, and global solar radiation since 2000. Such parameters allowed to apply five methods for reservoir evaporation estimate selected from those proposed in the literature, of which the first three, the Jensen-Haise's method, Makkink's method and Stephens-Stewart's one are based on solar radiation

  10. Estimating return periods of extreme values from relatively short time series of winds

    Science.gov (United States)

    Jonasson, Kristjan; Agustsson, Halfdan; Rognvaldsson, Olafur; Arfeuille, Gilles

    2013-04-01

    An important factor for determining the prospect of individual wind farm sites is the frequency of extreme winds at hub height. Here, extreme winds are defined as the value of the highest 10 minutes averaged wind speed with a 50 year return period, i.e. annual exceeding probability of 2% (Rodrigo, 2010). A frequently applied method to estimate winds in the lowest few hundred meters above ground is to extrapolate observed 10-meter winds logarithmically to higher altitudes. Recent study by Drechsel et al. (2012) showed however that this methodology is not as accurate as interpolating simulated results from the global ECMWF numerical weather prediction (NWP) model to the desired height. Observations of persistent low level jets near Colima in SW-Mexico also show that the logarithmic approach can give highly inaccurate results for some regions (Arfeuille et al., 2012). To address these shortcomings of limited, and/or poorly representative, observations and extrapolations of winds one can use NWP models to dynamically scale down relatively coarse resolution atmospheric analysis. In the case of limited computing resources one has typically to make a compromise between spatial resolution and the duration of the simulated period, both of which can limit the quality of the wind farm siting. A common method to estimate maximum winds is to fit an extreme value distribution (e.g. Gumbel, gev or Pareto) to the maximum values of each year of available data, or the tail of these values. If data are only available for a short period, e.g. 10 or 15 years, then this will give a rather inaccurate estimate. It is possible to deal with this problem by utilizing monthly or weekly maxima, but this introduces new problems: seasonal variation, autocorrelation of neighboring values, and increased discrepancy between data and fitted distribution. We introduce a new method to estimate return periods of extreme values of winds at hub height from relatively short time series of winds, simulated

  11. Probabilistic Models For Earthquakes With Large Return Periods In Himalaya Region

    Science.gov (United States)

    Chaudhary, Chhavi; Sharma, Mukat Lal

    2017-12-01

    Determination of the frequency of large earthquakes is of paramount importance for seismic risk assessment as large events contribute to significant fraction of the total deformation and these long return period events with low probability of occurrence are not easily captured by classical distributions. Generally, with a small catalogue these larger events follow different distribution function from the smaller and intermediate events. It is thus of special importance to use statistical methods that analyse as closely as possible the range of its extreme values or the tail of the distributions in addition to the main distributions. The generalised Pareto distribution family is widely used for modelling the events which are crossing a specified threshold value. The Pareto, Truncated Pareto, and Tapered Pareto are the special cases of the generalised Pareto family. In this work, the probability of earthquake occurrence has been estimated using the Pareto, Truncated Pareto, and Tapered Pareto distributions. As a case study, the Himalayas whose orogeny lies in generation of large earthquakes and which is one of the most active zones of the world, has been considered. The whole Himalayan region has been divided into five seismic source zones according to seismotectonic and clustering of events. Estimated probabilities of occurrence of earthquakes have also been compared with the modified Gutenberg-Richter distribution and the characteristics recurrence distribution. The statistical analysis reveals that the Tapered Pareto distribution better describes seismicity for the seismic source zones in comparison to other distributions considered in the present study.

  12. Return period curves for extreme 5-min rainfall amounts at the Barcelona urban network

    Science.gov (United States)

    Lana, X.; Casas-Castillo, M. C.; Serra, C.; Rodríguez-Solà, R.; Redaño, A.; Burgueño, A.; Martínez, M. D.

    2018-03-01

    Heavy rainfall episodes are relatively common in the conurbation of Barcelona and neighbouring cities (NE Spain), usually due to storms generated by convective phenomena in summer and eastern and south-eastern advections in autumn. Prevention of local flood episodes and right design of urban drainage have to take into account the rainfall intensity spread instead of a simple evaluation of daily rainfall amounts. The database comes from 5-min rain amounts recorded by tipping buckets in the Barcelona urban network along the years 1994-2009. From these data, extreme 5-min rain amounts are selected applying the peaks-over-threshold method for thresholds derived from both 95% percentile and the mean excess plot. The return period curves are derived from their statistical distribution for every gauge, describing with detail expected extreme 5-min rain amounts across the urban network. These curves are compared with those derived from annual extreme time series. In this way, areas in Barcelona submitted to different levels of flood risk from the point of view of rainfall intensity are detected. Additionally, global time trends on extreme 5-min rain amounts are quantified for the whole network and found as not statistically significant.

  13. Determining Storm Surge Return Periods: The Use of Evidence of Historic Events

    DEFF Research Database (Denmark)

    Madsen, Kristine S.; Sørensen, Carlo Sass; Schmith, Torben

    for tide gauge measurements, with 120 years of data available for the calculations. However, the oldest of these tide gauge stations was set up after a major storm surge in 1872, and no events of similar severity have occurred since. Including the evidence of the historic events from the 18th century...... changes the return period statistics, with a best estimate of a 100 year event changing from 1.5 meters (Sørensen et al. 2013) to 2.6 [2.2 – 2.8] meters (present study) in Køge just south of Copenhagen. Thus, with the tide gauge-based statistics, the storm surge on January 4 2017 was a 100 year event......, but with the revised statistics using historic evidence, much larger events can be expected. Further, we assess the very large impact of sea level rise on the storm surge statistics. As an example, according to the official statistics of southern Copenhagen, the flooding of a present day 100 year event...

  14. Uncertainties

    Indian Academy of Sciences (India)

    To reflect this uncertainty in the climate scenarios, the use of AOGCMs that explicitly simulate the carbon cycle and chemistry of all the substances are needed. The Hadley Centre has developed a version of the climate model that allows the effect of climate change on the carbon cycle and its feedback into climate, to be ...

  15. Uncertainty

    International Nuclear Information System (INIS)

    Silva, T.A. da

    1988-01-01

    The comparison between the uncertainty method recommended by International Atomic Energy Agency (IAEA) and the and the International Weight and Measure Commitee (CIPM) are showed, for the calibration of clinical dosimeters in the secondary standard Dosimetry Laboratory (SSDL). (C.G.C.) [pt

  16. Impacts of Return-to-Work Type and Period on Job Retention in Workers with Occupational Injuries and Diseases.

    Science.gov (United States)

    Jeong, Inchul; Park, Jae Bum; Kim, Hyoung Ryoul; Yoon, Jin Ha; Won, Jong Uk; Roh, Jaehoon

    2018-01-01

    Despite the necessity of job retention in achieving return-to-work (RTW) goals, many workers leave their jobs after returning to work. The objective of this study was to examine the impacts of RTW type and period on job retention in Korean workers with occupational injuries and diseases. Data were derived from the Panel Study of Worker's Compensation Insurance, including data from 2,000 systemically sampled workers who had finished recuperation in 2012; three waves of survey data were included in the analyses. Workers who returned to work (n = 1,610) were included in the analysis of the relationship between RTW type and job retention, and 664 workers who returned to their original workplaces were included in the analysis of the relationship between RTW period and job retention. The participants completed a questionnaire, and administrative data were provided by workers' compensation insurance. A Cox proportional-hazards regression analysis showed an increased hazard ratio (HR) for non-retention of 2.66 (95% confidence interval, 2.11-3.35) in reemployed workers compared to that in workers returning to their original workplaces. Among workers returning to their original workplaces, HRs for non-retention were increased in workers with a RTW period of 13-24 months (3.03 [1.52-6.04]) and > 24 months (5.33 [2.14-13.25]) compared to workers with a RTW period of ≤ 3 months. RTW type and period were significantly related to job retention, suggesting that policies for promoting job retention rate should be implemented. © 2018 The Korean Academy of Medical Sciences.

  17. STATISTICAL MODELLING OF FDC AND RETURN PERIODS TO CHARACTERISE QDF AND DESIGN THRESHOLD OF HYDROLOGICAL EXTREMES

    Directory of Open Access Journals (Sweden)

    Charles Onyutha

    2012-01-01

    Full Text Available In this paper, firstly, flow duration curves (FDCs for hydrological extremes were calibrated for a range of aggregation levels and seasons to provide compressed statistical information for water resources management at selected temporal scales and seasons. Secondly, instead of the common approach of using return periods, T (years for deriving discharge duration frequency (QDF relationships, the method of using exceedance frequencies, E (% was introduced so as to provide answer to important question like, what is the streamflow at a given aggregation level and selected E (%? Thirdly, the concept of estimated design threshold (EDT was introduced and proposed for consideration in the risk analysis for design of water resources structures. This study was based on the long daily discharge record for the period 1950 - 2008 at station 1EF01 in Kenya, on the Nzoia river with watershed area of 12,676 km² located in the North Eastern quadrant of Lake Victoria Nile Sub Basin. In the statistical modelling of FDCs and T (years, suitable extreme value distributions (EVD were selected and calibrated to fit nearly independent high flows and low flows. The FDCs and T-curves were used to determine the EDT. The FDCs were used to model the QDF relationships. To derive QDF relationships of hydrological extremes, for a given range of aggregation levels, extreme value analysis (EVA was carried out and suitable EVD selected. Next was the calibration of parameters of the EVD and analysis of relationship between the model parameters and aggregation levels. Finally, smooth mathematical relationships were derived using little but acceptable modifications to the model parameters. Such constructed QDF relationships can be used for various applications to estimate cumulative volumes of water available during droughts or floods at various aggregation levels or E (% of hydrological extremes. The EDT when obtained for a range of aggregation levels can also be used to understand

  18. STATISTICAL MODELLING OF FDC AND RETURN PERIODS TO CHARACTERISE QDF AND DESIGN THRESHOLD OF HYDROLOGICAL EXTREMES

    Directory of Open Access Journals (Sweden)

    Charles Onyutha

    2012-12-01

    Full Text Available In this paper, firstly, flow duration curves (FDCs for hydrological extremes were calibrated for a range of aggregation levels and seasons to provide compressed statistical information for water resources management at selected temporal scales and seasons. Secondly, instead of the common approach of using return periods, T (years for deriving discharge duration frequency (QDF relationships, the method of using exceedance frequencies, E (% was introduced so as to provide answer to important question like, what is the streamflow at a given aggregation level and selected E (%?. Thirdly, the concept of estimated design threshold (EDT was introduced and proposed for consideration in the risk analysis for design of water resources structures. This study was based on the long daily discharge record for the period 1950 – 2008 at station 1EF01 in Kenya, on the Nzoia river with watershed area of 12,676 km2 located in the North Eastern quadrant of Lake Victoria Nile Sub Basin. In the statistical modeling of FDCs and T (years, suitable extreme value distributions (EVD were selected and calibrated to fit nearly independent high flows and low flows. The FDCs and T-curves were used to determine the EDT. The FDCs were used to model the QDF relationships. To derive QDF relationships of hydrological extremes, for a given range of aggregation levels, extreme value analysis (EVA was carried out and suitable EVD selected. Next was the calibration of parameters of the EVD and analysis of relationship between the model parameters and aggregation levels. Finally, smooth mathematical relationships were derived using little but acceptable modifications to the model parameters. Such constructed QDF relationships can be used for various applications to estimate cumulative volumes of water available during droughts or floods at various aggregation levels or E (% of hydrological extremes. The EDT when obtained for a range of aggregation levels can also be used to

  19. A two-period model of emission abatement and allowance banking under uncertainty

    International Nuclear Information System (INIS)

    Hanson, D.A.

    1991-01-01

    This paper deals with the effects of uncertainty and risk aversion on market outcomes for SO 2 emission allowance prices and on electric utility compliance choices. The 1990 Clean Air Act Amendments (CAAA) provide about twice as many SO 2 allowances to be issued per year in Phase I (1995--1999) than in Phase II. Also, considering the scrubber incentives in Phase I, there is likely to be substantial emission banking for use in Phase II. Allowance prices may increase over time at a rate less than the return on alternative investments with allowances being banked only by risk averse electric utilities. Speculators are likely to be willing to set allowances in forward markets, which will lower current market prices of allowances relative to a situation with only risk averse utilities in the market. The Argonne Utility Simulation Model (ARGUS2) is being revised to incorporate the provisions of the CAAA acid rain title and to simulate SO 2 allowance prices, compliance choices, capacity expansion, system dispatch, fuel use, and emissions using a unit level data base and alternative scenario assumptions

  20. ANALISIS PENGARUH EVA DAN MVA TERHADAP RETURN SAHAM PADA INDUSTRI PROPERTI DI BURSA EFEK INDONESIA PERIODE 2007-2012

    Directory of Open Access Journals (Sweden)

    Ryan Pahlawan

    2015-04-01

    Full Text Available Abstrak: Tujuan dari penelitian ini adalah untuk mengetahui dan menganalisis: (1 pengaruh Economic Value Added (EVA terhadap return saham (2 pengaruh Market Value Added (MVA terhadap return saham (3 pengaruh Economic Value Added (EVA dan Market Value Added (MVA terhadap return saham antara variabel kinerja keuangan industri properti di Bursa Efek Indonesia pada periode 2007-2012. Kegunaan teoritis adalah untuk memberikan kontribusi tentang pengetahuan manajemen keuangan, yang dapat digunakan sebagai acuan untuk penelitian berikutnya kinerja keuangan terutama tentang industri properti di Bursa Efek Indonesia. Kegunaan praktis adalah untuk mengetahui pengaruh tingkat Economic Value Added (EVA dan Market Value Added (MVA terhadap kinerja keuangan untuk kontribusi memberi kepada manajemen properti umum dalam mengelola variabel kinerja industri properti Bursa Efek Indonesia.Penelitian ini menggunakan data sekunder yang dikumpulkan dari data Bursa Efek Indonesia, dan Departemen Riset menurut sifat laporan keuangan pada periode 2007-2012. Sampel adalah 54 variabel dan dianalisis dengan regresi berganda metode statistik linier. Total nilai determinasi adalah 0,368, artinya ini adalah 36,8% informasi dalam data dapat dijelaskan oleh model dan 63,2% di bawah variabel lain dan error. Kesimpulan dari penelitian ini adalah: (1 Variabel Economic Value Added (EVA berpengaruh positif terhadap return saham; (2 Variabel Market Value Added (MVA memiliki pengaruh negatif terhadap Return Saham; Mengacu pada kesimpulan penelitian diatas maka disarankan adalah: (1 Dioptimalkan Economic Value Added (EVA untuk mencapai pendapatan dan keuntungan dari return saham (2 Mengelola Variabel Market Value Added (MVA pada kondisi baik untuk menjaga stabilitas keuangan dan mendapatkan dipercaya dari investor Bursa Efek Indonesia (3 Fokus ke Manajemen Risiko, Jasa, perusahaan Visi & Misi, dan Active keterampilan dan pengetahuan karyawan perusahaan yang lebih tinggi untuk

  1. Women in post-trafficking services in moldova: diagnostic interviews over two time periods to assess returning women's mental health

    Directory of Open Access Journals (Sweden)

    Gorceag Lilia T

    2011-04-01

    found to have co-morbid PTSD or other forms of anxiety and depression immediately post-return should be offered evidenced-based mental health treatment for at least the standard 12-month period of rehabilitation.

  2. Urban flood return period assessment through rainfall-flood response modelling

    Science.gov (United States)

    Murla Tuyls, Damian; Thorndahl, Søren

    2017-04-01

    Intense rainfall can often cause severe floods, especially in urbanized areas, where population density or large impermeable areas are found. In this context, floods can generate a direct impact in a social-environmental-economic viewpoint. Traditionally, in design of Urban Drainage Systems (UDS), correlation between return period (RP) of a given rainfall and RP of its consequent flood has been assumed to be linear (e.g. DS/EN752 (2008)). However, this is not always the case. Complex UDS, where diverse hydraulic infrastructures are often found, increase the heterogeneity of system response, which may cause an alteration of the mentioned correlation. Consequently, reliability on future urban planning, design and resilience against floods may be also affected by this misassumption. In this study, an assessment of surface flood RP across rainfall RP has been carried out at Lystrup, a urbanized catchment area of 440ha and 10.400inhab. located in Jutland (Denmark), which has received the impact of several pluvial flooding in the last recent years. A historical rainfall dataset from the last 35 years from two different rain gauges located at 2 and 10 km from the study area has been provided by the Danish Wastewater Pollution Committee and the Danish Meteorological Institute (DMI). The most extreme 25 rainfall events have been selected through a two-step multi-criteria procedure, ensuring an adequate variability of rainfall, from extreme high peak storms with a short duration to moderate rainfall with longer duration. In addition, a coupled 1D/2D surface and network UDS model of the catchment area developed in an integrated MIKE URBAN and MIKE Flood model (DHI 2014), considering both permeable and impermeable areas, in combination with a DTM (2x2m res.) has been used to study and assess in detail flood RP. Results show an ambiguous relation between rainfall RP and flood response. Local flood levels, flood area and volume RP estimates should therefore not be neglected in

  3. Bivariate return periods of temperature and precipitation explain a large fraction of European crop yields

    Directory of Open Access Journals (Sweden)

    J. Zscheischler

    2017-07-01

    Full Text Available Crops are vital for human society. Crop yields vary with climate and it is important to understand how climate and crop yields are linked to ensure future food security. Temperature and precipitation are among the key driving factors of crop yield variability. Previous studies have investigated mostly linear relationships between temperature and precipitation and crop yield variability. Other research has highlighted the adverse impacts of climate extremes, such as drought and heat waves, on crop yields. Impacts are, however, often non-linearly related to multivariate climate conditions. Here we derive bivariate return periods of climate conditions as indicators for climate variability along different temperature–precipitation gradients. We show that in Europe, linear models based on bivariate return periods of specific climate conditions explain on average significantly more crop yield variability (42 % than models relying directly on temperature and precipitation as predictors (36 %. Our results demonstrate that most often crop yields increase along a gradient from hot and dry to cold and wet conditions, with lower yields associated with hot and dry periods. The majority of crops are most sensitive to climate conditions in summer and to maximum temperatures. The use of bivariate return periods allows the integration of non-linear impacts into climate–crop yield analysis. This offers new avenues to study the link between climate and crop yield variability and suggests that they are possibly more strongly related than what is inferred from conventional linear models.

  4. A new method for estimating maximum wind gust speed with a given return period and a high areal resolution

    Czech Academy of Sciences Publication Activity Database

    Pop, Lukáš; Sokol, Zbyněk; Hanslian, David

    2016-01-01

    Roč. 158, November (2016), s. 51-60 ISSN 0167-6105 R&D Projects: GA ČR GAP504/10/0843 Institutional support: RVO:68378289 Keywords : wind gusts * extreme wind map * return period * gumbel distribution * extreme value analysis Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 2.049, year: 2016 http://www.sciencedirect.com/science/article/pii/S0167610515301677

  5. Can the uncertainty appraisal associated with emotion cancel the effect of the hunch period in the Iowa Gambling Task?

    Science.gov (United States)

    Bollon, Thierry; Bagneux, Virginie

    2013-01-01

    Research has given little attention to the influence of incidental emotions on the Iowa Gambling Task (IGT), in which processing of the emotional cues associated with each decision is necessary to make advantageous decisions. Drawing on cognitive theories of emotions, we tested whether uncertainty-associated emotion can cancel the positive effect of the hunch period, by preventing participants from developing a tendency towards advantageous decisions. Our explanation is that uncertainty appraisals initiate deliberative processing that is irrelevant to process emotional cues, contrary to intuitive processing (Kahneman, 2003; Tiedens & Linton, 2001). As expected, uncertainty-associated emotion cancelled the positive effect of the hunch period in the IGT compared to certainty-associated emotion: disgusted participants (certainty-associated emotion) and sad participants induced to feel certainty developed a stronger tendency towards advantageous decisions than sad participants induced to feel uncertainty. We discuss the importance of the core components that trigger incidental emotions to predict decision making.

  6. Return to 1990: The cost of mitigating United States carbon emissions in the post-2000 period

    Energy Technology Data Exchange (ETDEWEB)

    Edmonds, J.A.; Kim, S.H.; MacCracken, C.N.; Sands, R.D.; Wise, M.A.

    1997-10-01

    The Second Generation Model (SGM) is employed to examine four hypothetical agreements to reduce emissions in Annex 1 nations (OECD nations plus most of the nations of Eastern Europe and the former Soviet Union) to levels in the neighborhood of those which existed in 1990, with obligations taking effect in the year 2010. The authors estimate the cost to the US of complying with such agreements under three distinct conditions: no trading of emissions rights, trading of emissions rights only among Annex 1 nations, and a fully global trading regime. The authors find that the marginal cost of returning to 1990 emissions levels in the US in the absence of trading opportunities is approximately $108 per metric ton carbon in 2010. The total cost in that year is approximately 0.2% of GDP. International trade in emissions permits lowers the cost of achieving any mitigation objective by equalizing the marginal cost of carbon mitigation among countries. For the four mitigation scenarios in this study, economic costs to the US remain below 1% of GDP through at least the year 2020.

  7. Uncertainty and sensitivity analyses of ballast life-cycle cost and payback period

    OpenAIRE

    Mcmahon, James E.

    2000-01-01

    The paper introduces an innovative methology for evaluating the relative significance of energy-efficient technologies applied to fluorescent lamp ballasts. The method involves replacing the point estimates of life cycle cost of the ballasts with uncertainty distributions reflecting the whole spectrum of possible costs, and the assessed probability associated with each value. The results of uncertainty and sensitivity analyses will help analysts reduce effort in data collection and carry on a...

  8. Uncertainty and sensitivity analyses of ballast life-cycle cost and payback period

    Energy Technology Data Exchange (ETDEWEB)

    McMahon, James E.; Liu, Xiaomin; Turiel, Ike; Hakim, Sajid; Fisher, Diane

    2000-06-01

    The paper introduces an innovative methodology for evaluating the relative significance of energy-efficient technologies applied to fluorescent lamp ballasts. The method involves replacing the point estimates of life cycle cost of the ballasts with uncertainty distributions reflecting the whole spectrum of possible costs, and the assessed probability associated with each value. The results of uncertainty and sensitivity analyses will help analysts reduce effort in data collection and carry on analysis more efficiently. These methods also enable policy makers to gain an insightful understanding of which efficient technology alternatives benefit or cost what fraction of consumers, given the explicit assumptions of the analysis.

  9. Building uncertainty into cost-effectiveness rankings: portfolio risk-return tradeoffs and implications for decision rules.

    Science.gov (United States)

    O'Brien, B J; Sculpher, M J

    2000-05-01

    Current principles of cost-effectiveness analysis emphasize the rank ordering of programs by expected economic return (eg, quality-adjusted life-years gained per dollar expended). This criterion ignores the variance associated with the cost-effectiveness of a program, yet variance is a common measure of risk when financial investment options are appraised. Variation in health care program return is likely to be a criterion of program selection for health care managers with fixed budgets and outcome performance targets. Characterizing health care resource allocation as a risky investment problem, we show how concepts of portfolio analysis from financial economics can be adopted as a conceptual framework for presenting cost-effectiveness data from multiple programs as mean-variance data. Two specific propositions emerge: (1) the current convention of ranking programs by expected return is a special case of the portfolio selection problem in which the decision maker is assumed to be indifferent to risk, and (2) for risk-averse decision makers, the degree of joint risk or covariation in cost-effectiveness between programs will create incentives to diversify an investment portfolio. The conventional normative assumption of risk neutrality for social-level public investment decisions does not apply to a large number of health care resource allocation decisions in which health care managers seek to maximize returns subject to budget constraints and performance targets. Portfolio theory offers a useful framework for studying mean-variance tradeoffs in cost-effectiveness and offers some positive predictions (and explanations) of actual decision making in the health care sector.

  10. Optimal Sizing of Energy Storage Systems for the Energy Procurement Problem in Multi-Period Markets under Uncertainties

    Directory of Open Access Journals (Sweden)

    Ryusuke Konishi

    2018-01-01

    Full Text Available In deregulated electricity markets, minimizing the procurement costs of electricity is a critical problem for procurement agencies (PAs. However, uncertainty is inevitable for PAs and includes multiple factors such as market prices, photovoltaic system (PV output and demand. This study focuses on settlements in multi-period markets (a day-ahead market and a real-time market and the installation of energy storage systems (ESSs. ESSs can be utilized for time arbitrage in the day-ahead market and to reduce the purchasing/selling of electricity in the real-time market. However, the high costs of an ESS mean the size of the system needs to be minimized. In addition, when determining the size of an ESS, it is important to identify the size appropriate for each role. Therefore, we employ the concept of a “slow” and a “fast” ESS to quantify the size of a system’s role, based on the values associated with the various uncertainties. Because the problem includes nonlinearity and non-convexity, we solve it within a realistic computational burden by reformulating the problem using reasonable assumptions. Therefore, this study identifies the optimal sizes of ESSs and procurement, taking into account the uncertainties of prices in multi-period markets, PV output and demand.

  11. Estimation of seismic return periods in the Laguna Verde nuclear plant; Estimacion de periodos de retorno sismico en la PNLV

    Energy Technology Data Exchange (ETDEWEB)

    Flores R, J.H

    1992-01-15

    The study of seismic risk in the area of the Laguna Verde Nucleo electric plant (PNLV) and its surroundings, one carries out estimating the different return periods and the occurrence probability in different intervals of time (5, 75, 100, 125, 150 years starting from the distribution of first type of Gumbel (G1) of extreme values (Burton, 1986), the value that was used to evaluate the useful life of the PNLV was of 50 years, the other periods will be occupy to evaluate 'temporal' nuclear cemeteries, that is to say for diminish the radioactive activity of the fuel assemblies already burned in the reactor pool or in a near place to the place. The seismic data that were used for the analysis were of the seismic catalog that it was elaborated from (1920-1982), around the place whose seismic half magnitude was of 5 grades Richter and a depth 65 km, these earthquakes are classified as shallow earthquakes, which are located in the continental plaque of North-America, these they are induced by the efforts of push of the plaque of Cocos, existing 36% of intermediate and 2 of deep earthquakes. (Author)

  12. Assessing spatial patterns of extreme droughts associated to return periods from observed dataset: Case study of Segura River Basin (Spain)

    Science.gov (United States)

    García Galiano, Sandra G.; Diego Giraldo Osorio, Juan

    2013-04-01

    In basins of South-eastern Spain, such as the Segura River Basin (SRB), a strong decrease in runoff from the end of the 1970s has been observed. In the SRB, due to intensive reforestation aimed at halting desertification and erosion, added to climate variability and change, the default assumption of stationarity in water resources systems cannot be guaranteed. Therefore there is an important need for improvement in the ability of monitoring and predicting the impacts associated with the change of hydrologic regime. It is thus necessary to apply non-stationary probabilistic models, which are able to reproduce probability density functions whose parameters vary with time. From a high-resolution daily gridded rainfall dataset of more than 50 years (1950-2007 time period), the spatial distribution of lengths of maximum dry spells for several thresholds are assessed, applying GAMLSS (Generalized Additive Models for Location Scale and Shape) models at grid site. Results reveal an intensification of extreme drought events in some headbasins of the SRB important for water supply. The identification of spatial patterns of drought hazards at basin scale, associated to return periods, contribute to designing strategies of drought contingency preparedness and recovery operations, which are the leading edge of adaptation strategies.

  13. Estimation of seismic return periods in the Laguna Verde nuclear plant; Estimacion de periodos de retorno sismico en la PNLV

    Energy Technology Data Exchange (ETDEWEB)

    Flores R, J H

    1992-01-15

    The study of seismic risk in the area of the Laguna Verde Nucleo electric plant (PNLV) and its surroundings, one carries out estimating the different return periods and the occurrence probability in different intervals of time (5, 75, 100, 125, 150 years starting from the distribution of first type of Gumbel (G1) of extreme values (Burton, 1986), the value that was used to evaluate the useful life of the PNLV was of 50 years, the other periods will be occupy to evaluate 'temporal' nuclear cemeteries, that is to say for diminish the radioactive activity of the fuel assemblies already burned in the reactor pool or in a near place to the place. The seismic data that were used for the analysis were of the seismic catalog that it was elaborated from (1920-1982), around the place whose seismic half magnitude was of 5 grades Richter and a depth 65 km, these earthquakes are classified as shallow earthquakes, which are located in the continental plaque of North-America, these they are induced by the efforts of push of the plaque of Cocos, existing 36% of intermediate and 2 of deep earthquakes. (Author)

  14. A system for generating long streamflow records for study of floods of long return period: Phase 2

    International Nuclear Information System (INIS)

    Franz, D.D.; Kraeger, B.A.; Linsley, R.K.

    1989-02-01

    Knowledge of the return periods of large floods is required to make risk analyses for nuclear power plants subject to flooding from rivers. The system reported here combined the stochastic simulation of hourly rainfall data and daily pan evaporation data with the deterministic simulation of streamflow by using the synthetic rainfall and evaporation data as input to a calibrated rainfall runoff model. The sequence of annual maximum flood peaks from a synthetic record of 10,000 years or more was then analyzed to obtain estimates of flood frequency. The reasonableness of the flood frequency results must be evaluated on the degree of mimicry of the key characteristics of the observed rainfall data and the ability of the rainfall-runoff model to mimic the observed flood frequency during the calibration period. On this basis, the flood frequency results appeared to be a reasonable extrapolation of the data used in defining the model parameters. There is a need to develop regional parameters for the stochastic models and to conduct research on the relationship between the stochastic structure of rainfall and stochastic structure of flood frequency. The methodology is applicable, assuming a highly skilled analyst, to watersheds similar to those already tested

  15. Projected Changes in Temperature and Precipitation Extremes over China as Measured by 50-yr Return Values and Periods Based on a CMIP5 Ensemble

    Science.gov (United States)

    Xu, Ying; Gao, Xuejie; Giorgi, Filippo; Zhou, Botao; Shi, Ying; Wu, Jie; Zhang, Yongxiang

    2018-04-01

    Future changes in the 50-yr return level for temperature and precipitation extremes over mainland China are investigated based on a CMIP5 multi-model ensemble for RCP2.6, RCP4.5 and RCP8.5 scenarios. The following indices are analyzed: TXx and TNn (the annual maximum and minimum of daily maximum and minimum surface temperature), RX5day (the annual maximum consecutive 5-day precipitation) and CDD (maximum annual number of consecutive dry days). After first validating the model performance, future changes in the 50-yr return values and return periods for these indices are investigated along with the inter-model spread. Multi-model median changes show an increase in the 50-yr return values of TXx and a decrease for TNn, more specifically, by the end of the 21st century under RCP8.5, the present day 50-yr return period of warm events is reduced to 1.2 yr, while extreme cold events over the country are projected to essentially disappear. A general increase in RX5day 50-yr return values is found in the future. By the end of the 21st century under RCP8.5, events of the present RX5day 50-yr return period are projected to reduce to China. Changes in CDD-50 show a dipole pattern over China, with a decrease in the values and longer return periods in the north, and vice versa in the south. Our study also highlights the need for further improvements in the representation of extreme events in climate models to assess the future risks and engineering design related to large-scale infrastructure in China.

  16. Dental work force strategies during a period of change and uncertainty.

    Science.gov (United States)

    Brown, L J

    2001-12-01

    Both supply and demand influence the ability of the dental work force to adequately and efficiently provide dental care to a U.S. population growing in size and diversity. Major changes are occurring on both sides of the dental care market. Among factors shaping the demand for dental care are changing disease patterns, shifting population demographics, the extent and features of third-party payment, and growth of the economy and the population. The capacity of the dental work force to provide care is influenced by enhancements of productivity and numbers of dental health personnel, as well as their demographic and practice characteristics. The full impact of these changes is difficult to predict. The dentist-to-population ratio does not reflect all the factors that must be considered to develop an effective dental work force policy. Nationally, the dental work force is likely to be adequate for the next several years, but regional work force imbalances appear to exist and may get worse. Against this backdrop of change and uncertainty, future dental work force strategies should strive for short-term responsiveness while avoiding long-term inflexibility. Trends in the work force must be continually monitored. Thorough analysis is required, and action should be taken when necessary.

  17. Introduction and application of non-stationary standardized precipitation index considering probability distribution function and return period

    Science.gov (United States)

    Park, Junehyeong; Sung, Jang Hyun; Lim, Yoon-Jin; Kang, Hyun-Suk

    2018-05-01

    The widely used meteorological drought index, the Standardized Precipitation Index (SPI), basically assumes stationarity, but recent changes in the climate have led to a need to review this hypothesis. In this study, a new non-stationary SPI that considers not only the modified probability distribution parameter but also the return period under the non-stationary process was proposed. The results were evaluated for two severe drought cases during the last 10 years in South Korea. As a result, SPIs considered that the non-stationary hypothesis underestimated the drought severity than the stationary SPI despite that these past two droughts were recognized as significantly severe droughts. It may be caused by that the variances of summer and autumn precipitation become larger over time then it can make the probability distribution wider than before. This implies that drought expressions by statistical index such as SPI can be distorted by stationary assumption and cautious approach is needed when deciding drought level considering climate changes.

  18. Pengaruh Rasio Modal Saham Terhadap Return Saham Perusahaan-Perusahaan Telekomunikasi Go Public di Indonesia Periode 2007

    Directory of Open Access Journals (Sweden)

    David Wijaya

    2008-01-01

    Full Text Available The purpose of this research is to know the influence of market value ratio to return in the telecommunication go public companies in Indonesia. This research uses multiple regression linear method, examination of hypothesis by using t test, F test and R2 test. The result of this analysis indicates that simultaneously all independent variables (ROE, PER, BVPS, and PTBV do not have a positive and significant effect to dependent variable (return. It means that return variable influenced by other variables which do not included in this research. Partially, all independent variables (ROE, PER, BVPS, and PTBV do not have a positive and significant effect to dependent variable (return Abstract in Bahasa Indonesia: Penelitian ini bertujuan untuk mengetahui pengaruh rasio modal saham terhadap return pada perusahaan-perusahaan telekomunikasi terbuka di Indonesia. Penelitian ini menggunakan metode analisis regresi linier berganda, pengujian hipotesis dengan menggunakan uji t, uji F, dan uji R2. Hasil analisis menunjukkan bahwa secara simultan (secara bersama-sama, semua variabel independen (ROE, PER, BVPS, dan PTBV secara signifikan dan positif tidak memiliki pengaruh terhadap variabel dependen (return. Hal ini berarti bahwa variabel return dipengaruhi oleh variabel-variabel lain yang tidak termasuk dalam penelitian ini. Secara parsial, semua variabel independen (ROE, PER, BVPS, dan PTBV tidak memiliki pengaruh secara signifikan dan positif terhadap variabel dependen (Return. Kata kunci: Laba atas ekuitas, harga-laba, nilai buku per lembar saham, harga saham per nilai buku, imbal hasil

  19. GJ 1214: Rotation period, starspots, and uncertainty on the optical slope of the transmission spectrum

    Science.gov (United States)

    Mallonn, M.; Herrero, E.; Juvan, I. G.; Essen, C. von; Rosich, A.; Ribas, I.; Granzer, T.; Alexoudi, X.; Strassmeier, K. G.

    2018-06-01

    Aims: Brightness inhomogeneities in the stellar photosphere (dark spots or bright regions) affect the measurements of the planetary transmission spectrum. To investigate the star spots of the M dwarf GJ 1214, we conducted a multicolor photometric monitoring from 2012 to 2016. Methods: The time-series photometry was analyzed with the light curve inversion tool StarSim. Using the derived stellar surface properties from the light curve inversion, we modeled the impact of the star spots when unocculted by the transiting planet. We compared the photometric variability of GJ 1214 to published results of mid- to late M dwarfs from the MEarth sample. Results: The measured variability shows a periodicity of 125 ± 5 days, which we interpret as the signature of the stellar rotation period. This value overrules previous suggestions of a significantly shorter stellar rotation period. A light curve inversion of the monitoring data yields an estimation of the flux dimming of a permanent spot filling factor not contributing to the photometric variability, a temperature contrast of the spots of 370 K and persistent active longitudes. The derived surface maps over all five seasons were used to estimate the influence of the star spots on the transmission spectrum of the planet from 400 to 2000 nm. The monitoring data presented here do not support a recent interpretation of a measured transmission spectrum of GJ 1214b as to be caused by bright regions in the stellar photosphere. Instead, we list arguments as to why the effect of dark spots likely dominated over bright regions in the period of our monitoring. Furthermore, our photometry proves an increase in variability over at least four years, indicative for a cyclic activity behavior. The age of GJ 1214 is likely between 6 and 10 Gyr. Conclusions: The long-term photometry allows for a correction of unocculted spots. For an active star such as GJ 1214, there remains a degeneracy between occulted spots and the transit parameters used

  20. A multi-period distribution network design model under demand uncertainty

    Science.gov (United States)

    Tabrizi, Babak H.; Razmi, Jafar

    2013-05-01

    Supply chain management is taken into account as an inseparable component in satisfying customers' requirements. This paper deals with the distribution network design (DND) problem which is a critical issue in achieving supply chain accomplishments. A capable DND can guarantee the success of the entire network performance. However, there are many factors that can cause fluctuations in input data determining market treatment, with respect to short-term planning, on the one hand. On the other hand, network performance may be threatened by the changes that take place within practicing periods, with respect to long-term planning. Thus, in order to bring both kinds of changes under control, we considered a new multi-period, multi-commodity, multi-source DND problem in circumstances where the network encounters uncertain demands. The fuzzy logic is applied here as an efficient tool for controlling the potential customers' demand risk. The defuzzifying framework leads the practitioners and decision-makers to interact with the solution procedure continuously. The fuzzy model is then validated by a sensitivity analysis test, and a typical problem is solved in order to illustrate the implementation steps. Finally, the formulation is tested by some different-sized problems to show its total performance.

  1. A Conceptual Model for Calculating the Return of Costs Invested in the Creation of an Economic Security Service, During a Short-Term Period

    Directory of Open Access Journals (Sweden)

    Melikhova Tetiana O.

    2018-02-01

    Full Text Available The article is aimed at suggesting methods for calculating the short-term period of return of costs invested in creation of an economic security service. The article considers approaches to calculation of the period of return of costs, advanced at the level of enterprise, which build the methodical basis for definition of such period. At the level of structural subdivisions of enterprise, which do not produce products, it is suggested to use conditional money flow as a source of financing advanced costs. The calculation of the short-term return on investment at the enterprise level provides for: allocation of expenses for the permanent and the replacement parts during the year; determination of the production of money flow and the money flow accumulated during the year. Annual depreciation payments are the basis of fixed costs. Methods of determination of the gross, net, valid, and specified periods of return of costs, advanced during the year for introduction of an economic security service at enterprise, have been suggested.

  2. Optimizing decentralized production-distribution planning problem in a multi-period supply chain network under uncertainty

    Science.gov (United States)

    Nourifar, Raheleh; Mahdavi, Iraj; Mahdavi-Amiri, Nezam; Paydar, Mohammad Mahdi

    2017-09-01

    Decentralized supply chain management is found to be significantly relevant in today's competitive markets. Production and distribution planning is posed as an important optimization problem in supply chain networks. Here, we propose a multi-period decentralized supply chain network model with uncertainty. The imprecision related to uncertain parameters like demand and price of the final product is appropriated with stochastic and fuzzy numbers. We provide mathematical formulation of the problem as a bi-level mixed integer linear programming model. Due to problem's convolution, a structure to solve is developed that incorporates a novel heuristic algorithm based on Kth-best algorithm, fuzzy approach and chance constraint approach. Ultimately, a numerical example is constructed and worked through to demonstrate applicability of the optimization model. A sensitivity analysis is also made.

  3. ANALISIS PENGARUH LDR, NPL DAN OPERATIONAL EFFICIENCY RATIO TERHADAP RETURN ON ASSETS PADA BANK DEVISA DI INDONESIA PERIODE 2010-2012

    OpenAIRE

    Hamidah Hamidah; Goldan Merion Siallagan; Umi Mardiyati

    2014-01-01

    This research is performed on order to test analysis the influence of the Loan to Deposit Ratio (LDR), Non Performing Loan (NPL) and Operational Efficiency Ratio (OER) toward Return On Asset (ROA) On Foreign Exchange Banks In Indonesia Period 2010-2012. Methodology research as the sample used purposive sampling, samplewas accured fromforeign banks in Indonesia. Data analysis with multi liniearregression of ordinary least square and hypotheses test used t-statistic and Fstatistic, a classic as...

  4. 26 CFR 1.6038-2 - Information returns required of United States persons with respect to annual accounting periods...

    Science.gov (United States)

    2010-04-01

    ... accounting period; (9) A list showing the name, address, and identifying number of, and the number of shares... United States dollars with a statement of the exchange rates used. The following rules shall apply for... functional currency as required on the form. Earnings and profits amounts furnished under paragraphs (f)(10...

  5. Decrypting Financial Markets through E-Joint Attention Efforts: On-Line Adaptive Networks of Investors in Periods of Market Uncertainty

    Science.gov (United States)

    Casnici, Niccolò; Dondio, Pierpaolo; Casarin, Roberto; Squazzoni, Flaminio

    2015-01-01

    This paper looks at 800,000 messages on the Unicredit stock, exchanged by 7,500 investors in the Finanzaonline.com forum, between 2005 and 2012 and measured collective interpretations of stock market trends. We examined the correlation patterns between market uncertainty, bad news and investors' network structure by measuring the investors' communication patterns. Our results showed that the investors' network reacted to market trends in different ways: While less turbulent market phases implied less communication, higher market volatility generated more complex communication patterns. While the information content of messages was less technical in situations of uncertainty, bad news caused more informative messages only when market volatility was lower. This meant that bad news had a different impact on network behaviour, depending on market uncertainty. By measuring the investors' expertise, we found that their behaviour could help predict changes in daily stock returns. We also found that expert investors were more influential in communication processes during high volatility market phases, whereas they had less influence on the real-time forum's reaction after bad news. Our findings confirm the crucial role of e-communication platforms. However, they also show the need to reconsider the fragility of these collective intelligence systems when under external shocks. PMID:26244550

  6. High-resolution refinement of a storm loss model and estimation of return periods of loss-intensive storms over Germany

    Directory of Open Access Journals (Sweden)

    M. G. Donat

    2011-10-01

    Full Text Available A refined model for the calculation of storm losses is presented, making use of high-resolution insurance loss records for Germany and allowing loss estimates on a spatial level of administrative districts and for single storm events. Storm losses are calculated on the basis of wind speeds from both ERA-Interim and NCEP reanalyses. The loss model reproduces the spatial distribution of observed losses well by taking specific regional loss characteristics into account. This also permits high-accuracy estimates of total cumulated losses, though slightly underestimating the country-wide loss sums for storm "Kyrill", the most severe event in the insurance loss records from 1997 to 2007. A larger deviation, which is assigned to the relatively coarse resolution of the NCEP reanalysis, is only found for one specific rather small-scale event, not adequately captured by this dataset.

    The loss model is subsequently applied to the complete reanalysis period to extend the storm event catalogue to cover years when no systematic insurance records are available. This allows the consideration of loss-intensive storm events back to 1948, enlarging the event catalogue to cover the recent 60+ years, and to investigate the statistical characteristics of severe storm loss events in Germany based on a larger sample than provided by the insurance records only. Extreme value analysis is applied to the loss data to estimate the return periods of loss-intensive storms, yielding a return period for storm "Kyrill", for example, of approximately 15 to 21 years.

  7. Pengaruh Downside Beta, Upside Beta, Dan Beta Terhadap Expected Return (Studi Pada Saham Yang Termasuk Dalam 50 Leading Market Capitalization Di Bursa Efek Indonesia Periode 2012-2015)

    OpenAIRE

    Sinaga, Maria Goretty; Sulasmiyati, Sri

    2017-01-01

    Return or return on an investment is required by the investor. Most investors currently prefer shares in emerging markets. Return in the emerging market is not always symmetrical, it shows return in the emerging market is not normally distributed. The purposive of this research want to learn, compare, and explain about some model of stock risk. On this research downside risk expressed with beta downside. The models used in this research among others, dowside beta, upside beta, and beta. The k...

  8. Return to sexual activity and modern family planning use in the extended postpartum period: an analysis of findings from seventeen countries.

    Science.gov (United States)

    Borda, Maria R; Winfrey, William; McKaig, Catharine

    2010-12-01

    Unintended pregnancies can lead to poor maternal and child health outcomes. Family planning use during the first year postpartum has the potential to significantly reduce at least some of these unintended pregnancies. This paper examines the relationship of menses return, breastfeeding status, and postpartum duration on return to sexual activity and use of modern family planning among postpartum women. This paper presents results from a secondary data analysis of Demographic and Health Surveys from 17 countries. For postpartum women, the return of menses, breastfeeding status, and postpartum duration are significantly associated with return to sexual activity in at least 10 out of the 17 countries but not consistently associated with family planning use. Only menses return had a significant association with use of modern family planning in the majority of countries. These findings point to the importance of education about pregnancy risk prior to menses return.

  9. ANALISIS PENGARUH LDR, NPL DAN OPERATIONAL EFFICIENCY RATIO TERHADAP RETURN ON ASSETS PADA BANK DEVISA DI INDONESIA PERIODE 2010-2012

    Directory of Open Access Journals (Sweden)

    Hamidah Hamidah

    2014-04-01

    Full Text Available This research is performed on order to test analysis the influence of the Loan to Deposit Ratio (LDR, Non Performing Loan (NPL and Operational Efficiency Ratio (OER toward Return On Asset (ROA On Foreign Exchange Banks In Indonesia Period 2010-2012. Methodology research as the sample used purposive sampling, sample was accrued from foreign banks in Indonesia. Data analysis with multi linear regression of ordinary least square and hypotheses test used t-statistic and F statistic, a classic assumption examination to test the hypotheses.Based on normality test, multicolinearity test, heterosskedasticity test and auto correlation test were not found variables that deviate from the classical assumptions, this indicate that the available data has fulfill the condition to use multi linear regression model. This result of research show that variable LDR and NPL partially have positive influence but not significant toward ROA. Variable OERpartially have negative significant influence toward ROA. Variable LDR, NPL and OER simultaneously have significant influence toward ROA.

  10. 26 CFR 1.6694-4 - Extension of period of collection when tax return preparer pays 15 percent of a penalty for...

    Science.gov (United States)

    2010-04-01

    ... TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES Additions to the Tax, Additional Amounts, and... assessment, the IRS will also send, before assessment of either penalty, a 30-day letter to the tax return preparer notifying him of the proposed penalty or penalties and offering an opportunity to the tax return...

  11. PENGARUH EARNINGS, OPERATING CASH FLOW DAN ASSET GROWTH TERHADAP STOCK RETURN PERUSAHAAN YANG TERDAFTAR PADA INDEKS LQ 45 UNTUK PERIODE 2009-2011

    Directory of Open Access Journals (Sweden)

    Yulius ,

    2017-02-01

    Full Text Available The objective of this research is to test the impact of earnings, operating cash flow and asset growth to firm’s stock return which listed in LQ 45 index in Indonesian for 2009-2011. The result of this research is earnings, operating cash flow and asset growth have not significant effect to stock return both when those variabels is tested separately or silmutaneously. This result show that earnings, operating cash flow and asset growth are not only the one to be the basis of consideration for investor to make investment to get the stock return. Therefore, for making investment, investor should consider other factors which effect the firm’s stock return as macro economics and politics. Furthermore, from this result, be expected an improvement of quality financial statement which addopted IFRS. Keyword: Earnings, Operating Cash Flow, Asset Growth, Stock Return.

  12. The role of global economic policy uncertainty in long-run volatilities and correlations of U.S. industry-level stock returns and crude oil.

    Science.gov (United States)

    Yu, Honghai; Fang, Libing; Sun, Boyang

    2018-01-01

    We investigate how Global Economic Policy Uncertainty (GEPU) drives the long-run components of volatilities and correlations in crude oil and U.S. industry-level stock markets. Using the modified generalized autoregressive conditional heteroskedasticity mixed data sampling (GARCH-MIDAS) and dynamic conditional correlation mixed data sampling (DCC-MIDAS) specifications, we find that GEPU is positively related to the long-run volatility of Financials and Consumer Discretionary industries; however, it is negatively related to Information Technology, Materials, Telecommunication Services and Energy. Unlike the mixed role of GEPU in the long-run volatilities, the long-run correlations are all positively related to GEPU across the industries. Additionally, the rankings of the correlations of Energy and Materials are time-invariant and classified as high, with the little exception of the latter. The Consumer Staples industry is time-invariant in the low-ranking group. Our results are helpful to policy makers and investors with long-term concerns.

  13. Hotspots of gross emissions from the land use sector: patterns, uncertainties, and leading emission sources for the period 2000-2005 in the tropics

    Science.gov (United States)

    Roman-Cuesta, Rosa Maria; Rufino, Mariana C.; Herold, Martin; Butterbach-Bahl, Klaus; Rosenstock, Todd S.; Herrero, Mario; Ogle, Stephen; Li, Changsheng; Poulter, Benjamin; Verchot, Louis; Martius, Christopher; Stuiver, John; de Bruin, Sytze

    2016-07-01

    According to the latest report of the Intergovernmental Panel on Climate Change (IPCC), emissions must be cut by 41-72 % below 2010 levels by 2050 for a likely chance of containing the global mean temperature increase to 2 °C. The AFOLU sector (Agriculture, Forestry and Other Land Use) contributes roughly a quarter ( ˜ 10-12 Pg CO2e yr-1) of the net anthropogenic GHG emissions mainly from deforestation, fire, wood harvesting, and agricultural emissions including croplands, paddy rice, and livestock. In spite of the importance of this sector, it is unclear where the regions with hotspots of AFOLU emissions are and how uncertain these emissions are. Here we present a novel, spatially comparable dataset containing annual mean estimates of gross AFOLU emissions (CO2, CH4, N2O), associated uncertainties, and leading emission sources, in a spatially disaggregated manner (0.5°) for the tropics for the period 2000-2005. Our data highlight the following: (i) the existence of AFOLU emissions hotspots on all continents, with particular importance of evergreen rainforest deforestation in Central and South America, fire in dry forests in Africa, and both peatland emissions and agriculture in Asia; (ii) a predominant contribution of forests and CO2 to the total AFOLU emissions (69 %) and to their uncertainties (98 %); (iii) higher gross fluxes from forests, which coincide with higher uncertainties, making agricultural hotspots appealing for effective mitigation action; and (iv) a lower contribution of non-CO2 agricultural emissions to the total gross emissions (ca. 25 %), with livestock (15.5 %) and rice (7 %) leading the emissions. Gross AFOLU tropical emissions of 8.0 (5.5-12.2) were in the range of other databases (8.4 and 8.0 Pg CO2e yr-1 in FAOSTAT and the Emissions Database for Global Atmospheric Research (EDGAR) respectively), but we offer a spatially detailed benchmark for monitoring progress in reducing emissions from the land sector in the tropics. The location of

  14. Coping with Economic Uncertainty: Focus on Key Risks Essential

    Science.gov (United States)

    Sander, Laura

    2009-01-01

    During this period of continued economic uncertainty, higher-education institutions are facing a variety of challenges that by now are very familiar to governing boards and institutional leaders, including poor investment returns, reduced liquidity, limited choices in how they structure debt issues, and threats to flexibility in tuition pricing.…

  15. PENERAPAN MODEL ARBITRAGE PRICING THEORY DENGAN PENDEKATAN VECTOR AUTOREGRESSION DALAM MENGESTIMASI EXPECTED RETURN SAHAM (Studi Kasus: Saham-Saham Kompas100 Periode 2010-2013

    Directory of Open Access Journals (Sweden)

    VIAN RISKA AYUNING TYAS

    2014-01-01

    Full Text Available The Arbitrage Pricing Theory (APT is an alternative model to estimate the price of securities based of arbitrage concept. In APT, the returns of securities are affected by several factors. This research is aimed to estimate the expected returns of securities using APT model and Vector Autoregressive model. There are ten stocks incorporated in Kompas100 index and four macroeconomic variables, these are inflation, exchange rates, the amountof circulate money (JUB, and theinterest rateof Bank Indonesia(SBI are applied in this research. The first step in using VAR is to test the stationary of the data using colerogram and the results indicate that all data are stationary. The second step is to select the optimal lag based on the smallest value of AIC. The Granger causality test shows that the LPKR stock is affected by the inflation and the exchange rate while the nine other stocks do not show the existence of the expected causality. The results of causality test are then estimated by the VAR models in order to obtain expected returnof macroeconomic factors. The expected return of macroeconomic factors obtained is used in the APT model, then the expected return stock LPKR is calculated. It shows that the expected return of LPKR is 3,340%

  16. PENERAPAN MODEL ARBITRAGE PRICING THEORY DENGAN PENDEKATAN VECTOR AUTOREGRESSION DALAM MENGESTIMASI EXPECTED RETURN SAHAM (Studi Kasus: Saham-Saham Kompas100 Periode 2010-2013

    Directory of Open Access Journals (Sweden)

    VIAN RISKA AYUNING TYAS

    2014-08-01

    Full Text Available The Arbitrage Pricing Theory (APT is an alternative model to estimate the price of securities based of arbitrage concept. In APT, the returns of securities are affected by several factors. This research is aimed to estimate the expected returns of securities using APT model and Vector Autoregressive model. There are ten stocks incorporated in Kompas100 index and four macroeconomic variables, these are inflation, exchange rates, the amountof circulate money (JUB, and theinterest rateof Bank Indonesia(SBI are applied in this research. The first step in using VAR is to test the stationary of the data using colerogram and the results indicate that all data are stationary. The second step is to select the optimal lag based on the smallest value of AIC. The Granger causality test shows that the LPKR stock is affected by the inflation and the exchange rate while the nine other stocks do not show the existence of the expected causality. The results of causality test are then estimated by the VAR models in order to obtain expected returnof macroeconomic factors. The expected return of macroeconomic factors obtained is used in the APT model, then the expected return stock LPKR is calculated. It shows that the expected return of LPKR is 3,340%

  17. Pengaruh Profitabilitas Terhadap Intial Return Dilihat Dari Aspek Cash Basis Dan Accrual Basis (Studi Pada Perusahaan Yang Melakukan Initial Public Offering (Ipo Di Bursa Efek Indonesia Periode Januari 2011 – Agustus 2015

    Directory of Open Access Journals (Sweden)

    Miranti Dewi Febriani

    2017-07-01

    Full Text Available The study aims to examine the effect of profitability on Initial Return based on cash basis and accrual basis. The population in this study is companies performing IPO in period of January 2011 – Augustus 2015 as many as 111 companies and are adjusted to several criteria in order to get as many as 70 companies for model 1, 72 companies for model 2, and 53 companies for model 3. It uses simple regression analysis technique assisted by Gretl Software. Interstingly, only ROE affect Initial Return and model 1 has highest R2.

  18. Uncertainty in oil projects

    International Nuclear Information System (INIS)

    Limperopoulos, G.J.

    1995-01-01

    This report presents an oil project valuation under uncertainty by means of two well-known financial techniques: The Capital Asset Pricing Model (CAPM) and The Black-Scholes Option Pricing Formula. CAPM gives a linear positive relationship between expected rate of return and risk but does not take into consideration the aspect of flexibility which is crucial for an irreversible investment as an oil price is. Introduction of investment decision flexibility by using real options can increase the oil project value substantially. Some simple tests for the importance of uncertainty in stock market for oil investments are performed. Uncertainty in stock returns is correlated with aggregate product market uncertainty according to Pindyck (1991). The results of the tests are not satisfactory due to the short data series but introducing two other explanatory variables the interest rate and Gross Domestic Product make the situation better. 36 refs., 18 figs., 6 tabs

  19. Photometric Uncertainties

    Science.gov (United States)

    Zou, Xiao-Duan; Li, Jian-Yang; Clark, Beth Ellen; Golish, Dathon

    2018-01-01

    The OSIRIS-REx spacecraft, launched in September, 2016, will study the asteroid Bennu and return a sample from its surface to Earth in 2023. Bennu is a near-Earth carbonaceous asteroid which will provide insight into the formation and evolution of the solar system. OSIRIS-REx will first approach Bennu in August 2018 and will study the asteroid for approximately two years before sampling. OSIRIS-REx will develop its photometric model (including Lommel-Seelinger, ROLO, McEwen, Minnaert and Akimov) of Bennu with OCAM and OVIRS during the Detailed Survey mission phase. The model developed during this phase will be used to photometrically correct the OCAM and OVIRS data.Here we present the analysis of the error for the photometric corrections. Based on our testing data sets, we find:1. The model uncertainties is only correct when we use the covariance matrix to calculate, because the parameters are highly correlated.2. No evidence of domination of any parameter in each model.3. And both model error and the data error contribute to the final correction error comparably.4. We tested the uncertainty module on fake and real data sets, and find that model performance depends on the data coverage and data quality. These tests gave us a better understanding of how different model behave in different case.5. L-S model is more reliable than others. Maybe because the simulated data are based on L-S model. However, the test on real data (SPDIF) does show slight advantage of L-S, too. ROLO is not reliable to use when calculating bond albedo. The uncertainty of McEwen model is big in most cases. Akimov performs unphysical on SOPIE 1 data.6. Better use L-S as our default choice, this conclusion is based mainly on our test on SOPIE data and IPDIF.

  20. Deprem Magnitüdleri İçin Tekrarlanma Yıllarının Elde Edilmesi : Marmara Bölgesi Örneği = Obtaining the Return Period of Earthquake Magnitudes : As an Example Marmara Region

    Directory of Open Access Journals (Sweden)

    Reşat KASAP

    2003-06-01

    Full Text Available In this study, statistical analysis have been done for 447 earthquake occurrences data, between north (39.500-41.500 and east (26.000-32.500 coordinates in the Marmara Region from 1900 to 2000. It has been found that the probability density and distribution functions of magnitude random variable, and then the return period of earthquakes of various magnitudes have been found.

  1. Technical note: Design flood under hydrological uncertainty

    Science.gov (United States)

    Botto, Anna; Ganora, Daniele; Claps, Pierluigi; Laio, Francesco

    2017-07-01

    Planning and verification of hydraulic infrastructures require a design estimate of hydrologic variables, usually provided by frequency analysis, and neglecting hydrologic uncertainty. However, when hydrologic uncertainty is accounted for, the design flood value for a specific return period is no longer a unique value, but is represented by a distribution of values. As a consequence, the design flood is no longer univocally defined, making the design process undetermined. The Uncertainty Compliant Design Flood Estimation (UNCODE) procedure is a novel approach that, starting from a range of possible design flood estimates obtained in uncertain conditions, converges to a single design value. This is obtained through a cost-benefit criterion with additional constraints that is numerically solved in a simulation framework. This paper contributes to promoting a practical use of the UNCODE procedure without resorting to numerical computation. A modified procedure is proposed by using a correction coefficient that modifies the standard (i.e., uncertainty-free) design value on the basis of sample length and return period only. The procedure is robust and parsimonious, as it does not require additional parameters with respect to the traditional uncertainty-free analysis. Simple equations to compute the correction term are provided for a number of probability distributions commonly used to represent the flood frequency curve. The UNCODE procedure, when coupled with this simple correction factor, provides a robust way to manage the hydrologic uncertainty and to go beyond the use of traditional safety factors. With all the other parameters being equal, an increase in the sample length reduces the correction factor, and thus the construction costs, while still keeping the same safety level.

  2. Erosividade das chuvas associada a períodos de retorno e probabilidade de ocorrência no estado do Rio de Janeiro Rainfall erosivity associated to return periods and occurrence probability in the state of Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    Roriz Luciano Machado

    2013-04-01

    Full Text Available O conhecimento da erosividade das chuvas associada à probabilidade de ocorrência e ao período de retorno pode contribuir para o planejamento conservacionista de uma região, em médio e longo prazo. A fim de gerar informações para melhor utilizar modelos e controle da erosão, dados de chuvas de 30 séries pluviográficas e pluviométricas, abrangendo 25 municípios, entre 1933 e 2006, foram estudados quanto à adequação das séries e do cálculo da probabilidade de ocorrência teórica (P e período de retorno (T da erosividade das chuvas (EI30 e KE>25, para o Estado do Rio de Janeiro. Foi feita a espacialização do potencial erosivo associado aos períodos de retorno de 2, 5, 10, 20, 50 e 100 anos para todo o Estado. A erosividade anual média (EI30 ou fator R da USLE para qualquer localidade no Estado do Rio de Janeiro pode ser igualada ou superada pelo menos uma vez, em média, em um período de 1,8 a 2,1 anos, com faixa de 48,5 a 54,9 % de probabilidade de ocorrência teórica. As localidades que apresentam maior erosividade associada aos períodos de retorno estão situadas nas mesorregiões Metropolitanas e em partes das mesorregiões Sul e Centro Fluminense. Foi possível identificar de oito a 12 regiões homogêneas, quanto à distribuição espacial da erosividade associada aos períodos de retorno de dois para 100 anos no Estado. De modo geral, a maior variação da distribuição espacial da erosividade apresenta-se na faixa de período de retorno de dois a cinco anos.Knowledge on rainfall erosivity associated to occurrence probability and return periods can contribute to conservation planning in the medium and long term. With the objective of generating information for a better use of medium and long-term erosion models and erosion control, rainfall data of 30 pluviometric and pluviographic data sets from 25 cities ranging from 1933 to 2006 were studied in terms of adjustment of data sets, calculation of the probability of

  3. Designing for Uncertainty: Three Approaches

    Science.gov (United States)

    Bennett, Scott

    2007-01-01

    Higher education wishes to get long life and good returns on its investment in learning spaces. Doing this has become difficult because rapid changes in information technology have created fundamental uncertainties about the future in which capital investments must deliver value. Three approaches to designing for this uncertainty are described…

  4. Effect of uncertainties on probabilistic-based design capacity of hydrosystems

    Science.gov (United States)

    Tung, Yeou-Koung

    2018-02-01

    Hydrosystems engineering designs involve analysis of hydrometric data (e.g., rainfall, floods) and use of hydrologic/hydraulic models, all of which contribute various degrees of uncertainty to the design process. Uncertainties in hydrosystem designs can be generally categorized into aleatory and epistemic types. The former arises from the natural randomness of hydrologic processes whereas the latter are due to knowledge deficiency in model formulation and model parameter specification. This study shows that the presence of epistemic uncertainties induces uncertainty in determining the design capacity. Hence, the designer needs to quantify the uncertainty features of design capacity to determine the capacity with a stipulated performance reliability under the design condition. Using detention basin design as an example, the study illustrates a methodological framework by considering aleatory uncertainty from rainfall and epistemic uncertainties from the runoff coefficient, curve number, and sampling error in design rainfall magnitude. The effects of including different items of uncertainty and performance reliability on the design detention capacity are examined. A numerical example shows that the mean value of the design capacity of the detention basin increases with the design return period and this relation is found to be practically the same regardless of the uncertainty types considered. The standard deviation associated with the design capacity, when subject to epistemic uncertainty, increases with both design frequency and items of epistemic uncertainty involved. It is found that the epistemic uncertainty due to sampling error in rainfall quantiles should not be ignored. Even with a sample size of 80 (relatively large for a hydrologic application) the inclusion of sampling error in rainfall quantiles resulted in a standard deviation about 2.5 times higher than that considering only the uncertainty of the runoff coefficient and curve number. Furthermore, the

  5. Inventory control with product returns : The impact of imperfect information

    NARCIS (Netherlands)

    De Brito, M.P.; Laan, E.A.

    2009-01-01

    Product returns are characterized by considerable uncertainty on time and quantity. In the literature on inventory management for product return environments best forecasts of future returns are associated with methods that use the most information regarding product return history. In practice,

  6. The Returns to Entrepreneurship

    DEFF Research Database (Denmark)

    Van Praag, Mirjam; Raknerud, Arvid

    Empirical studies show low pecuniary returns of switching from wage employment to entrepreneurship. We reconsider the pecuniary gains of this switching by employing a two-stage procedure, where the randomness in the timing of inheritance transfers is used as an exclusion restriction to identify...... causal effects. The model is estimated on data covering the whole Norwegian population of individuals matched to the entire population of firms established in the period 2002-2011. The results indicate that the average returns to entrepreneurship are significantly negative for individuals entering...... entrepreneurship through self-employment and modest, but significantly positive, for incorporated startups....

  7. Gold Returns

    OpenAIRE

    Robert J. Barro; Sanjay P. Misra

    2013-01-01

    From 1836 to 2011, the average real rate of price change for gold in the United States is 1.1% per year and the standard deviation is 13.1%, implying a one-standard-deviation confidence band for the mean of (0.1%, 2.1%). The covariances of gold's real rate of price change with consumption and GDP growth rates are small and statistically insignificantly different from zero. These negligible covariances suggest that gold's expected real rate of return--which includes an unobserved dividend yiel...

  8. Returning home

    DEFF Research Database (Denmark)

    Agergaard, Jytte; Brøgger, Ditte

    2016-01-01

    flows. By focusing on these educational migrants, this paper explores how they connect to their rural homes. Guided by a critical reading of the migration-development scholarship, the paper examines how migrants and their relatives make sense of educational migrants’ remitting and returning practices......, and by comparing three groups of educational migrants, the migrants’ reasons for staying connected and sending remittances are scrutinized. The paper finds that although educational migrants do not generate extensive economic remittances for local development in Nepal, they stay connected to their rural homes...

  9. Understanding uncertainty

    CERN Document Server

    Lindley, Dennis V

    2013-01-01

    Praise for the First Edition ""...a reference for everyone who is interested in knowing and handling uncertainty.""-Journal of Applied Statistics The critically acclaimed First Edition of Understanding Uncertainty provided a study of uncertainty addressed to scholars in all fields, showing that uncertainty could be measured by probability, and that probability obeyed three basic rules that enabled uncertainty to be handled sensibly in everyday life. These ideas were extended to embrace the scientific method and to show how decisions, containing an uncertain element, could be rationally made.

  10. Uncertainties in Integrated Climate Change Impact Assessments by Sub-setting GCMs Based on Annual as well as Crop Growing Period under Rice Based Farming System of Indo-Gangetic Plains of India

    Science.gov (United States)

    Pillai, S. N.; Singh, H.; Panwar, A. S.; Meena, M. S.; Singh, S. V.; Singh, B.; Paudel, G. P.; Baigorria, G. A.; Ruane, A. C.; McDermid, S.; Boote, K. J.; Porter, C.; Valdivia, R. O.

    2016-12-01

    Integrated assessment of climate change impact on agricultural productivity is a challenge to the scientific community due to uncertainties of input data, particularly the climate, soil, crop calibration and socio-economic dataset. However, the uncertainty due to selection of GCMs is the major source due to complex underlying processes involved in initial as well as the boundary conditions dealt in solving the air-sea interactions. Under Agricultural Modeling Intercomparison and Improvement Project (AgMIP), the Indo-Gangetic Plains Regional Research Team investigated the uncertainties caused due to selection of GCMs through sub-setting based on annual as well as crop-growth period of rice-wheat systems in AgMIP Integrated Assessment methodology. The AgMIP Phase II protocols were used to study the linking of climate-crop-economic models for two study sites Meerut and Karnal to analyse the sensitivity of current production systems to climate change. Climate Change Projections were made using 29 CMIP5 GCMs under RCP4.5 and RCP 8.5 during mid-century period (2040-2069). Two crop models (APSIM & DSSAT) were used. TOA-MD economic model was used for integrated assessment. Based on RAPs (Representative Agricultural Pathways), some of the parameters, which are not possible to get through modeling, derived from literature and interactions with stakeholders incorporated into the TOA-MD model for integrated assessment.

  11. Measurement Uncertainty

    Science.gov (United States)

    Koch, Michael

    Measurement uncertainty is one of the key issues in quality assurance. It became increasingly important for analytical chemistry laboratories with the accreditation to ISO/IEC 17025. The uncertainty of a measurement is the most important criterion for the decision whether a measurement result is fit for purpose. It also delivers help for the decision whether a specification limit is exceeded or not. Estimation of measurement uncertainty often is not trivial. Several strategies have been developed for this purpose that will shortly be described in this chapter. In addition the different possibilities to take into account the uncertainty in compliance assessment are explained.

  12. Impacts of representing sea-level rise uncertainty on future flood risks: An example from San Francisco Bay.

    Science.gov (United States)

    Ruckert, Kelsey L; Oddo, Perry C; Keller, Klaus

    2017-01-01

    Rising sea levels increase the probability of future coastal flooding. Many decision-makers use risk analyses to inform the design of sea-level rise (SLR) adaptation strategies. These analyses are often silent on potentially relevant uncertainties. For example, some previous risk analyses use the expected, best, or large quantile (i.e., 90%) estimate of future SLR. Here, we use a case study to quantify and illustrate how neglecting SLR uncertainties can bias risk projections. Specifically, we focus on the future 100-yr (1% annual exceedance probability) coastal flood height (storm surge including SLR) in the year 2100 in the San Francisco Bay area. We find that accounting for uncertainty in future SLR increases the return level (the height associated with a probability of occurrence) by half a meter from roughly 2.2 to 2.7 m, compared to using the mean sea-level projection. Accounting for this uncertainty also changes the shape of the relationship between the return period (the inverse probability that an event of interest will occur) and the return level. For instance, incorporating uncertainties shortens the return period associated with the 2.2 m return level from a 100-yr to roughly a 7-yr return period (∼15% probability). Additionally, accounting for this uncertainty doubles the area at risk of flooding (the area to be flooded under a certain height; e.g., the 100-yr flood height) in San Francisco. These results indicate that the method of accounting for future SLR can have considerable impacts on the design of flood risk management strategies.

  13. Impacts of representing sea-level rise uncertainty on future flood risks: An example from San Francisco Bay.

    Directory of Open Access Journals (Sweden)

    Kelsey L Ruckert

    Full Text Available Rising sea levels increase the probability of future coastal flooding. Many decision-makers use risk analyses to inform the design of sea-level rise (SLR adaptation strategies. These analyses are often silent on potentially relevant uncertainties. For example, some previous risk analyses use the expected, best, or large quantile (i.e., 90% estimate of future SLR. Here, we use a case study to quantify and illustrate how neglecting SLR uncertainties can bias risk projections. Specifically, we focus on the future 100-yr (1% annual exceedance probability coastal flood height (storm surge including SLR in the year 2100 in the San Francisco Bay area. We find that accounting for uncertainty in future SLR increases the return level (the height associated with a probability of occurrence by half a meter from roughly 2.2 to 2.7 m, compared to using the mean sea-level projection. Accounting for this uncertainty also changes the shape of the relationship between the return period (the inverse probability that an event of interest will occur and the return level. For instance, incorporating uncertainties shortens the return period associated with the 2.2 m return level from a 100-yr to roughly a 7-yr return period (∼15% probability. Additionally, accounting for this uncertainty doubles the area at risk of flooding (the area to be flooded under a certain height; e.g., the 100-yr flood height in San Francisco. These results indicate that the method of accounting for future SLR can have considerable impacts on the design of flood risk management strategies.

  14. Forecasting return products in an integrated forward/reverse supply chain utilizing an ANFIS

    Directory of Open Access Journals (Sweden)

    Kumar D. Thresh

    2014-09-01

    Full Text Available Interests in Closed-Loop Supply Chain (CLSC issues are growing day by day within the academia, companies, and customers. Many papers discuss profitability or cost reduction impacts of remanufacturing, but a very important point is almost missing. Indeed, there is no guarantee about the amounts of return products even if we know a lot about demands of first products. This uncertainty is due to reasons such as companies’ capabilities in collecting End-of-Life (EOL products, customers’ interests in returning (and current incentives, and other independent collectors. The aim of this paper is to deal with the important gap of the uncertainties of return products. Therefore, we discuss the forecasting method of return products which have their own open-loop supply chain. We develop an integrated two-phase methodology to cope with the closed-loop supply chain design and planning problem. In the first phase, an Adaptive Network Based Fuzzy Inference System (ANFIS is presented to handle the uncertainties of the amounts of return product and to determine the forecasted return rates. In the second phase, and based on the results of the first one, the proposed multi-echelon, multi-product, multi-period, closed-loop supply chain network is optimized. The second-phase optimization is undertaken based on using general exact solvers in order to achieve the global optimum. Finally, the performance of the proposed forecasting method is evaluated in 25 periods using a numerical example, which contains a pattern in the returning of products. The results reveal acceptable performance of the proposed two-phase optimization method. Based on them, such forecasting approaches can be applied to real-case CLSC problems in order to achieve more reliable design and planning of the network

  15. Fundamental volatility and stock returns : does fundamental volatility explain stock returns?

    OpenAIRE

    Selboe, Guner K.; Virdee, Jaspal Singh

    2017-01-01

    In this thesis, we investigate whether the fundamental uncertainty can explain the crosssection of stock returns. To measure the fundamental uncertainty, we estimate rolling standard deviations and accounting betas of four different fundamentals: revenues, gross profit, earnings and cash flows. The standard deviation and the beta of revenues significantly explain returns in the Fama-Macbeth procedure, but only appears significant among smaller stocks in the portfolio formation ...

  16. PERIODIC REVIEW SYSTEM FOR INVENTORY REPLENISHMENT CONTROL FOR A TWO-ECHELON LOGISTICS NETWORK UNDER DEMAND UNCERTAINTY: A TWO-STAGE STOCHASTIC PROGRAMING APPROACH

    OpenAIRE

    Cunha, P.S.A.; Oliveira, F.; Raupp, Fernanda M.P.

    2017-01-01

    ABSTRACT Here, we propose a novel methodology for replenishment and control systems for inventories of two-echelon logistics networks using a two-stage stochastic programming, considering periodic review and uncertain demands. In addition, to achieve better customer services, we introduce a variable rationing rule to address quantities of the item in short. The devised models are reformulated into their deterministic equivalent, resulting in nonlinear mixed-integer programming models, which a...

  17. PERIODIC REVIEW SYSTEM FOR INVENTORY REPLENISHMENT CONTROL FOR A TWO-ECHELON LOGISTICS NETWORK UNDER DEMAND UNCERTAINTY: A TWO-STAGE STOCHASTIC PROGRAMING APPROACH

    Directory of Open Access Journals (Sweden)

    P.S.A. Cunha

    Full Text Available ABSTRACT Here, we propose a novel methodology for replenishment and control systems for inventories of two-echelon logistics networks using a two-stage stochastic programming, considering periodic review and uncertain demands. In addition, to achieve better customer services, we introduce a variable rationing rule to address quantities of the item in short. The devised models are reformulated into their deterministic equivalent, resulting in nonlinear mixed-integer programming models, which are then approximately linearized. To deal with the uncertain nature of the item demand levels, we apply a Monte Carlo simulation-based method to generate finite and discrete sets of scenarios. Moreover, the proposed approach does not require restricted assumptions to the behavior of the probabilistic phenomena, as does several existing methods in the literature. Numerical experiments with the proposed approach for randomly generated instances of the problem show results with errors around 1%.

  18. Rainfall erosivity and rainfall return period in the experimental watershed of Aracruz, in the coastal plain of Espirito Santo, Brazil Erosividade da chuva e tempo de retorno na bacia experimental da Aracruz, região dos tabuleiros costeiros brasileiros

    Directory of Open Access Journals (Sweden)

    Sérgio Gualberto Martins

    2010-06-01

    Full Text Available Knowledge on the factors influencing water erosion is fundamental for the choice of the best land use practices. Rainfall, expressed by rainfall erosivity, is one of the most important factors of water erosion. The objective of this study was to determine rainfall erosivity and the return period of rainfall in the Coastal Plains region, near Aracruz, a town in the state of Espírito Santo, Brazil, based on available data. Rainfall erosivity was calculated based on historic rainfall data, collected from January 1998 to July 2004 at 5 min intervals, by automatic weather stations of the Aracruz Cellulose S.A company. A linear regression with individual rainfall and erosivity data was fit to obtain an equation that allowed data extrapolation to calculate individual erosivity for a 30-year period. Based on this data the annual average rainfall erosivity in Aracruz was 8,536 MJ mm ha-1 h-1 yr-1. Of the total annual rainfall erosivity 85 % was observed in the most critical period October to March. Annual erosive rains accounted for 38 % of the events causing erosion, although the runoff volume represented 88 % of the total. The annual average rainfall erosivity return period was estimated to be 3.4 years.O conhecimento dos fatores que influenciam a erosão hídrica é de fundamental importância no planejamento do uso do solo. Dos fatores que alteram a erosão, a precipitação pluvial, expressa pela erosividade da chuva, é um dos mais importantes. Assim, o objetivo deste estudo foi determinar a erosividade e o tempo de retorno para a região dos Tabuleiros Costeiros, no município de Aracruz, ES. Para o cálculo da erosividade, foram utilizados dados pluviométricos de janeiro de 1998 a julho de 2004, obtidos em estações climatológicas automatizadas, localizadas em área experimental da Aracruz Celulose AS, que, para este estudo, geraram dados de 5 em 5 min. A análise de regressão linear entre precipitação pluvial e erosidade para esse per

  19. Uncertainty theory

    CERN Document Server

    Liu, Baoding

    2015-01-01

    When no samples are available to estimate a probability distribution, we have to invite some domain experts to evaluate the belief degree that each event will happen. Perhaps some people think that the belief degree should be modeled by subjective probability or fuzzy set theory. However, it is usually inappropriate because both of them may lead to counterintuitive results in this case. In order to rationally deal with belief degrees, uncertainty theory was founded in 2007 and subsequently studied by many researchers. Nowadays, uncertainty theory has become a branch of axiomatic mathematics for modeling belief degrees. This is an introductory textbook on uncertainty theory, uncertain programming, uncertain statistics, uncertain risk analysis, uncertain reliability analysis, uncertain set, uncertain logic, uncertain inference, uncertain process, uncertain calculus, and uncertain differential equation. This textbook also shows applications of uncertainty theory to scheduling, logistics, networks, data mining, c...

  20. Stay the Course or Seize an Opportunity? Options for Alberta’s Post-Secondary Institutions in a Period of Uncertainty About the Rebound of the Oil Economy

    Directory of Open Access Journals (Sweden)

    Ken Norrie

    2017-09-01

    Full Text Available Colleges and universities in Alberta feel the booms and busts of the oil-driven economy, too. When oil prices are high, and oil exploration and new project construction are booming, post-secondary institutions will often find themselves unable to keep up with the demand for the education and skills-training programs that employers are clamouring for, with fewer spots available for students than there are students eager to fill them. When oil prices drop, and exploration and construction dry up, the schools face the opposite problem: They have too much capacity in the kinds of programs for skills that traditionally serve those sectors directly connected to oil, or closely linked to them, where there is suddenly a glut of available labour. Making matters particularly complicated is that when oil prices fall, there is never any certainty of when they will rebound. If the lower oil prices are short lived like after 2009, colleges and universities have needed only to be patient and ride out shortterm disruptions, without the need to restructure their program offerings. However, that was not the case after 1985, where oil prices stagnated for an extended period of time. Now, some observers project that the decline in oil prices that began in 2014, with prices yet to fully recover, could last even longer, perhaps with oil becoming the “new coal” and remaining in glut indefinitely. Not knowing whether oil prices will rebound sooner, later, or never puts Alberta’s post-secondary institutions in a tricky situation. Their programs providing skilled workers to the province’s oil-based economy are longstanding and well-respected and the prospect of shrinking them or dismantling them, and shifting a school’s focus to different programming priorities, should not be taken lightly as it could be very expensive to reverse if oil prices do indeed end up rebounding. But if they do not, they will nevertheless face pressure to do so, anyway, due to the

  1. Erosividade, coeficiente de chuva, padrões e período de retorno das chuvas de Quaraí, RS Erosivity, rainfall coefficient and patterns and return period in Quarai, RS, Brazi

    Directory of Open Access Journals (Sweden)

    Marcos Gabriel Peñalva Bazzano

    2007-10-01

    intermediário e 18 % do atrasado. Das chuvas erosivas, 57 % da erosividade correspondeu a chuvas do padrão avançado, 25 % a chuvas do padrão intermediário e 18 % a chuvas do padrão atrasado.The planning of agricultural and civil engineering activities must be based on knowledge of rainfall erosion potential. For Quarai, RS, Brazil, the rainfall erosivity and its relationship with precipitation and rainfall coefficient, rainfall patterns and rainfall return period were determined. Daily rainfall data from the 1966-2003 period were used. For each erosive rainfall the segments of the rainfall chart with the same intensity were separated and the data recorded in a worksheet. The mean precipitation and rainfall patterns were estimated, as well as the monthly and annual erosivity by the EI30 index (International System of Units, using the software Chuveros. The rainfall coefficient was calculated. Pearson correlations and linear regressions between the erosivity index EI30 and the mean annual precipitation and rainfall coefficient (Rc were performed. The rainfall maximum intensity was calculated by the method of extreme distribution type I for different rainfall durations (1/6, 1/3, 1/2, 1, 2, 4, 8, 12, 24 and 48 h and rainfall return periods (2, 5, 10, 20, 50 and 100 years. Equations were adjusted that relate the maximum intensity and rainfall duration to all return periods, by the method of simple linear regression, and the rainfall characteristics related in a graph. The mean annual values of EI30 (R factor of USLE determined for Quarai, RS, Brazil, was 9,292 MJ mm ha-1 h-1 year-1. The following equations were obtained: EI30 = -754.37 + 13.50 p (r² = 0.85 and EI30 = -47.35 + 82.72 Rc (r² = 0.84. In relation to the total precipitation studied, 44 % of the number of rainfalls and 90 % of the volume were erosive. Of the total rainfalls evaluated, 44 % of the number and 90 % of the volume were erosive. Of the total erosive rainfall events, 51 % had an advanced, 25 % had an

  2. Uncertainties in repository modeling

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, J.R.

    1996-12-31

    The distant future is ver difficult to predict. Unfortunately, our regulators are being enchouraged to extend ther regulatory period form the standard 10,000 years to 1 million years. Such overconfidence is not justified due to uncertainties in dating, calibration, and modeling.

  3. Uncertainties in repository modeling

    International Nuclear Information System (INIS)

    Wilson, J.R.

    1996-01-01

    The distant future is ver difficult to predict. Unfortunately, our regulators are being enchouraged to extend ther regulatory period form the standard 10,000 years to 1 million years. Such overconfidence is not justified due to uncertainties in dating, calibration, and modeling

  4. Remanufacturing lot-sizing under alternative perceptions of returned units' quality

    Directory of Open Access Journals (Sweden)

    Zikopoulos, C.

    2012-01-01

    Full Text Available One of the critical parameters in reverse supply chain management is the increased variability of the quality condition of used, returned products. The volatile nature of returns' quality often dictates the establishment of quality assessment procedures and the development of technologies that facilitate the fast, accurate and inexpensive classification of returns. The appropriate degree in which a firm has to allocate resources for acquiring information on the quality of returned units, naturally, depends on the anticipated improvement of recovery activities' profitability. Therefore, the quantification of the savings associated with confronting or resolving quality uncertainty is a necessary input during the determination of the proper recovery procedures' configuration. In the current paper, we study a remanufacturing system in a multi-period setting in which returns' quality information is exploited during remanufacturing planning. However, in the decision-making process, certain aspects of the problem examined, such as the quantification of shortage cost, are overlooked or simplified. The objective is to examine the advisability of acquiring advanced quality information in order to be used during sub-optimal decision-making processes, in comparison with alternative policies which do not take explicitly into account returns' quality information. Moreover, through an extensive numerical analysis we examine the implications of alternative considerations regarding returned units' quality on remanufacturing planning, lead-time and service-levels and evaluate their impact on the overall system operational cost.

  5. 26 CFR 1.6013-2 - Joint return after filing separate return.

    Science.gov (United States)

    2010-04-01

    ... the case of a joint return made under section 6013(b), the period of limitations provided in sections... (c)(1) of this section, relating to the application of sections 6501 and 6651 with respect to a joint... 26 Internal Revenue 13 2010-04-01 2010-04-01 false Joint return after filing separate return. 1...

  6. Teaching Uncertainties

    Science.gov (United States)

    Duerdoth, Ian

    2009-01-01

    The subject of uncertainties (sometimes called errors) is traditionally taught (to first-year science undergraduates) towards the end of a course on statistics that defines probability as the limit of many trials, and discusses probability distribution functions and the Gaussian distribution. We show how to introduce students to the concepts of…

  7. Calibration uncertainty

    DEFF Research Database (Denmark)

    Heydorn, Kaj; Anglov, Thomas

    2002-01-01

    Methods recommended by the International Standardization Organisation and Eurachem are not satisfactory for the correct estimation of calibration uncertainty. A novel approach is introduced and tested on actual calibration data for the determination of Pb by ICP-AES. The improved calibration...

  8. Return-to-Work Program for Injured Workers: Factors of Successful Return to Employment.

    Science.gov (United States)

    Awang, Halimah; Shahabudin, Sharifah Muhairah; Mansor, Norma

    2016-11-01

    This study examined the factors of successful return to employment among participants in the return to work program (RTW) following work-related injury. Data were obtained from the Social Security Organization database containing 9850 injured workers who underwent RTW in 2010 to 2013. About 65% had successfully returned to employment. Significant factors of successful return include gender, employer interest, motivation, age, intervention duration, and type of injury. Male and motivated employees were more likely to return to employment compared with female and unmotivated employees, respectively. Participants from interested employers were 23.22 times more likely to return to work than those from uninterested employers, whereas participants whose intervention period exceeded 5 months were 41% less likely to return to work compared with those whose intervention period was within 3 months. Appropriate strategy and enhanced collaboration between the stakeholders would improve the proportion of successful return to employment. © 2016 APJPH.

  9. Demand Uncertainty

    DEFF Research Database (Denmark)

    Nguyen, Daniel Xuyen

    This paper presents a model of trade that explains why firms wait to export and why many exporters fail. Firms face uncertain demands that are only realized after the firm enters the destination. The model retools the timing of uncertainty resolution found in productivity heterogeneity models....... This retooling addresses several shortcomings. First, the imperfect correlation of demands reconciles the sales variation observed in and across destinations. Second, since demands for the firm's output are correlated across destinations, a firm can use previously realized demands to forecast unknown demands...... in untested destinations. The option to forecast demands causes firms to delay exporting in order to gather more information about foreign demand. Third, since uncertainty is resolved after entry, many firms enter a destination and then exit after learning that they cannot profit. This prediction reconciles...

  10. Uncertainty, joint uncertainty, and the quantum uncertainty principle

    International Nuclear Information System (INIS)

    Narasimhachar, Varun; Poostindouz, Alireza; Gour, Gilad

    2016-01-01

    Historically, the element of uncertainty in quantum mechanics has been expressed through mathematical identities called uncertainty relations, a great many of which continue to be discovered. These relations use diverse measures to quantify uncertainty (and joint uncertainty). In this paper we use operational information-theoretic principles to identify the common essence of all such measures, thereby defining measure-independent notions of uncertainty and joint uncertainty. We find that most existing entropic uncertainty relations use measures of joint uncertainty that yield themselves to a small class of operational interpretations. Our notion relaxes this restriction, revealing previously unexplored joint uncertainty measures. To illustrate the utility of our formalism, we derive an uncertainty relation based on one such new measure. We also use our formalism to gain insight into the conditions under which measure-independent uncertainty relations can be found. (paper)

  11. The 'successful' return

    DEFF Research Database (Denmark)

    Olwig, Karen Fog

    2012-01-01

    Research on female migrant caregivers has tended to focus upon the emotional and social problems they encounter working abroad, given women’s traditional role as caregivers for their own families. This article analyses how Caribbean women who have returned after a period abroad as domestic workers...... inscribe their migration experiences within the gendered narrative of the good relative who migrates to help the family left behind and therefore deserves social recognition in the community of origin. It argues that this narrative allows the women to both affirm and reinterpret local family and gender...... roles within the context of migration. This analysis points to the close connection between narrative structures, accounts of migration experiences, and self-presentations and suggests that narratives about family and gender roles not only reflect people’s lives, but are also a malleable resource...

  12. Stock returns and foreign investment in Brazil

    OpenAIRE

    Reis, Luciana; Meurer, Roberto; Da Silva, Sergio

    2008-01-01

    We examine the relationship between stock returns and foreign investment in Brazil, and find that the inflows of foreign investment boosted the returns from 1995 to 2005. There was a strong contemporaneous correlation, although not Granger-causality. Foreign investment along with the exchange rate, the influence of the world stock markets, and country risk can explain 73 percent of the changes that occurred in the stock returns over the period. We also find that positive feedback trading play...

  13. Uncertainty analysis

    International Nuclear Information System (INIS)

    Thomas, R.E.

    1982-03-01

    An evaluation is made of the suitability of analytical and statistical sampling methods for making uncertainty analyses. The adjoint method is found to be well-suited for obtaining sensitivity coefficients for computer programs involving large numbers of equations and input parameters. For this purpose the Latin Hypercube Sampling method is found to be inferior to conventional experimental designs. The Latin hypercube method can be used to estimate output probability density functions, but requires supplementary rank transformations followed by stepwise regression to obtain uncertainty information on individual input parameters. A simple Cork and Bottle problem is used to illustrate the efficiency of the adjoint method relative to certain statistical sampling methods. For linear models of the form Ax=b it is shown that a complete adjoint sensitivity analysis can be made without formulating and solving the adjoint problem. This can be done either by using a special type of statistical sampling or by reformulating the primal problem and using suitable linear programming software

  14. Predictability of Stock Returns

    Directory of Open Access Journals (Sweden)

    Ahmet Sekreter

    2017-06-01

    Full Text Available Predictability of stock returns has been shown by empirical studies over time. This article collects the most important theories on forecasting stock returns and investigates the factors that affecting behavior of the stocks’ prices and the market as a whole. Estimation of the factors and the way of estimation are the key issues of predictability of stock returns.

  15. ANALYSING TURKISH INDIVIDUAL PENSION SYSTEM FEES AND RETURNS

    OpenAIRE

    Peker, Ibrahim

    2018-01-01

    This study aims at categorizing, computing and analyzing fees and costs in Turkish Individual Pension System. To this end, net real returns after all costs were computed and these returns were compared with the disclosed fees and returns. Generally in practice, only fund management fees are taken into consideration for calculating net returns and with this method net annual average (geometric) return of the system is calculated as 2.01% for the 2008-2014 period. However, the results of this s...

  16. Computing the distribution of return levels of extreme warm temperatures for future climate projections

    Energy Technology Data Exchange (ETDEWEB)

    Pausader, M.; Parey, S.; Nogaj, M. [EDF/R and D, Chatou Cedex (France); Bernie, D. [Met Office Hadley Centre, Exeter (United Kingdom)

    2012-03-15

    In order to take into account uncertainties in the future climate projections there is a growing demand for probabilistic projections of climate change. This paper presents a methodology for producing such a probabilistic analysis of future temperature extremes. The 20- and 100-years return levels are obtained from that of the normalized variable and the changes in mean and standard deviation given by climate models for the desired future periods. Uncertainty in future change of these extremes is quantified using a multi-model ensemble and a perturbed physics ensemble. The probability density functions of future return levels are computed at a representative location from the joint probability distribution of mean and standard deviation changes given by the two combined ensembles of models. For the studied location, the 100-years return level at the end of the century is lower than 41 C with an 80% confidence. Then, as the number of model simulations is low to compute a reliable distribution, two techniques proposed in the literature (local pattern scaling and ANOVA) have been used to infer the changes in mean and standard deviation for the combinations of RCM and GCM which have not been run. The ANOVA technique leads to better results for the reconstruction of the mean changes, whereas the two methods fail to correctly infer the changes in standard deviation. As standard deviation change has a major impact on return level change, there is a need to improve the models and the different techniques regarding the variance changes. (orig.)

  17. Uncertainty as Certaint

    Science.gov (United States)

    Petzinger, Tom

    I am trying to make money in the biotech industry from complexity science. And I am doing it with inspiration that I picked up on the edge of Appalachia spending time with June Holley and ACEnet when I was a Wall Street Journal reporter. I took some of those ideas to Pittsburgh, in biotechnology, in a completely private setting with an economic development focus, but also with a mission t o return profit to private capital. And we are doing that. I submit as a hypothesis, something we are figuring out in the post- industrial era, that business evolves. It is not the definition of business, but business critically involves the design of systems in which uncertainty is treated as a certainty. That is what I have seen and what I have tried to put into practice.

  18. Uncertainty estimation of Intensity-Duration-Frequency relationships: A regional analysis

    Science.gov (United States)

    Mélèse, Victor; Blanchet, Juliette; Molinié, Gilles

    2018-03-01

    We propose in this article a regional study of uncertainties in IDF curves derived from point-rainfall maxima. We develop two generalized extreme value models based on the simple scaling assumption, first in the frequentist framework and second in the Bayesian framework. Within the frequentist framework, uncertainties are obtained i) from the Gaussian density stemming from the asymptotic normality theorem of the maximum likelihood and ii) with a bootstrap procedure. Within the Bayesian framework, uncertainties are obtained from the posterior densities. We confront these two frameworks on the same database covering a large region of 100, 000 km2 in southern France with contrasted rainfall regime, in order to be able to draw conclusion that are not specific to the data. The two frameworks are applied to 405 hourly stations with data back to the 1980's, accumulated in the range 3 h-120 h. We show that i) the Bayesian framework is more robust than the frequentist one to the starting point of the estimation procedure, ii) the posterior and the bootstrap densities are able to better adjust uncertainty estimation to the data than the Gaussian density, and iii) the bootstrap density give unreasonable confidence intervals, in particular for return levels associated to large return period. Therefore our recommendation goes towards the use of the Bayesian framework to compute uncertainty.

  19. Active screening and surveillance in the United Kingdom for Middle East respiratory syndrome coronavirus in returning travellers and pilgrims from the Middle East: a prospective descriptive study for the period 2013–2015

    Directory of Open Access Journals (Sweden)

    Sowsan F. Atabani

    2016-06-01

    Conclusions: Respiratory tract infections in travellers/pilgrims returning to the UK from the Middle East are mainly due to rhinoviruses, influenza A, and influenza B. Whilst MERS-CoV was not detected in the 202 patients studied, heightened awareness of the possibility of MERS-CoV and continuous proactive surveillance are essential to rapidly identify cases of MERS-CoV and other seasonal respiratory tract viruses such as avian influenza, in patients presenting to hospital. Early identification and isolation may prevent outbreaks in nosocomial settings.

  20. Back to the green jewel. After a period of using fossil fuels, Costa Rica is returning to renewable energy sources; Zurueck zum gruenen Juwel. Nach einem Ausflug zu den fossilen Brennstoffen kehrt Costa Rica zurueck zu den erneuerbaren Energien

    Energy Technology Data Exchange (ETDEWEB)

    Bosworth, Melissa

    2010-07-15

    For more than two decades now, Costa Rica has been a Mecca for eco-tourists. Deep rainforests, empty beeches and an incredible variety of species have made the country into one of the forerunners of sustainability. This picture was marred by the fact that fossil fuels were getting more attention by the government recently. Now, however, Costa Rica is returning to renewable energy sources which had already supplied 100 percent of the country's total power. The government is even considering reimbursement tariffs for solar power. (orig.)

  1. Returning to work after disability.

    Science.gov (United States)

    Quinn, P Roger

    2002-06-01

    After a workplace injury or disability, there is a period of hardship and adjustment for the injured party as well as all stakeholders in the workers' compensation process. Ultimately, however, return to work is considered. The author reviews this often challenging exercise from the Canadian perspective and stresses the need for timely intervention, honest communication, the coordination of information and resources--and the need for flexibility. A case study on low back pain is included.

  2. Tail Risk Premia and Return Predictability

    DEFF Research Database (Denmark)

    Bollerslev, Tim; Todorov, Viktor; Xu, Lai

    The variance risk premium, defined as the difference between actual and risk-neutralized expectations of the forward aggregate market variation, helps predict future market returns. Relying on new essentially model-free estimation procedure, we show that much of this predictability may be attribu......The variance risk premium, defined as the difference between actual and risk-neutralized expectations of the forward aggregate market variation, helps predict future market returns. Relying on new essentially model-free estimation procedure, we show that much of this predictability may......-varying economic uncertainty and changes in risk aversion, or market fears, respectively....

  3. Uncertainty analysis in safety assessment

    International Nuclear Information System (INIS)

    Lemos, Francisco Luiz de; Sullivan, Terry

    1997-01-01

    Nuclear waste disposal is a very complex subject which requires the study of many different fields of science, like hydro geology, meteorology, geochemistry, etc. In addition, the waste disposal facilities are designed to last for a very long period of time. Both of these conditions make safety assessment projections filled with uncertainty. This paper addresses approaches for treatment of uncertainties in the safety assessment modeling due to the variability of data and some current approaches used to deal with this problem. (author)

  4. Predictable return distributions

    DEFF Research Database (Denmark)

    Pedersen, Thomas Quistgaard

    trace out the entire distribution. A univariate quantile regression model is used to examine stock and bond return distributions individually, while a multivariate model is used to capture their joint distribution. An empirical analysis on US data shows that certain parts of the return distributions......-of-sample analyses show that the relative accuracy of the state variables in predicting future returns varies across the distribution. A portfolio study shows that an investor with power utility can obtain economic gains by applying the empirical return distribution in portfolio decisions instead of imposing...

  5. Uncertainty modeling and decision support

    International Nuclear Information System (INIS)

    Yager, Ronald R.

    2004-01-01

    We first formulate the problem of decision making under uncertainty. The importance of the representation of our knowledge about the uncertainty in formulating a decision process is pointed out. We begin with a brief discussion of the case of probabilistic uncertainty. Next, in considerable detail, we discuss the case of decision making under ignorance. For this case the fundamental role of the attitude of the decision maker is noted and its subjective nature is emphasized. Next the case in which a Dempster-Shafer belief structure is used to model our knowledge of the uncertainty is considered. Here we also emphasize the subjective choices the decision maker must make in formulating a decision function. The case in which the uncertainty is represented by a fuzzy measure (monotonic set function) is then investigated. We then return to the Dempster-Shafer belief structure and show its relationship to the fuzzy measure. This relationship allows us to get a deeper understanding of the formulation the decision function used Dempster- Shafer framework. We discuss how this deeper understanding allows a decision analyst to better make the subjective choices needed in the formulation of the decision function

  6. Is the Return to the Virtual US Dollar Pegging of East Asian Currencies Correct? : The Impacts of the Yen-Dollar Exchange Rate on the East Asian Currencies in the Post Crisis Period

    OpenAIRE

    金, 炳宣; Byung Sun, Kim; 経済学研究科

    2004-01-01

    This paper studies the evolution of the exchange rate regime on East Asian economies between pre- and post-crisis periods, especially with a focus on the impacts of change in yen-dollar rate, using a regression model based on the work by Frankel and Wei (1994). As a result of the study, the following points are understood. Firstly, a greater diversity in exchange rate regime is seen for the post-crisis period than the pre-crisis period. At one extreme, Hong Kong under a stable dollar peg thro...

  7. Classifying Returns as Extreme

    DEFF Research Database (Denmark)

    Christiansen, Charlotte

    2014-01-01

    I consider extreme returns for the stock and bond markets of 14 EU countries using two classification schemes: One, the univariate classification scheme from the previous literature that classifies extreme returns for each market separately, and two, a novel multivariate classification scheme tha...

  8. The redoubtable ecological periodic table

    Science.gov (United States)

    Ecological periodic tables are repositories of reliable information on quantitative, predictably recurring (periodic) habitat–community patterns and their uncertainty, scaling and transferability. Their reliability derives from their grounding in sound ecological principle...

  9. Quantifying uncertainties in wind energy assessment

    Science.gov (United States)

    Patlakas, Platon; Galanis, George; Kallos, George

    2015-04-01

    The constant rise of wind energy production and the subsequent penetration in global energy markets during the last decades resulted in new sites selection with various types of problems. Such problems arise due to the variability and the uncertainty of wind speed. The study of the wind speed distribution lower and upper tail may support the quantification of these uncertainties. Such approaches focused on extreme wind conditions or periods below the energy production threshold are necessary for a better management of operations. Towards this direction, different methodologies are presented for the credible evaluation of potential non-frequent/extreme values for these environmental conditions. The approaches used, take into consideration the structural design of the wind turbines according to their lifespan, the turbine failures, the time needed for repairing as well as the energy production distribution. In this work, a multi-parametric approach for studying extreme wind speed values will be discussed based on tools of Extreme Value Theory. In particular, the study is focused on extreme wind speed return periods and the persistence of no energy production based on a weather modeling system/hind cast/10-year dataset. More specifically, two methods (Annual Maxima and Peaks Over Threshold) were used for the estimation of extreme wind speeds and their recurrence intervals. Additionally, two different methodologies (intensity given duration and duration given intensity, both based on Annual Maxima method) were implied to calculate the extreme events duration, combined with their intensity as well as the event frequency. The obtained results prove that the proposed approaches converge, at least on the main findings, for each case. It is also remarkable that, despite the moderate wind speed climate of the area, several consequent days of no energy production are observed.

  10. Handling uncertainty

    DEFF Research Database (Denmark)

    Jønsson, Jesper Bosse; Fold, Niels

    2009-01-01

    Small-scale mining supports the livelihoods of several hundred thousand rural households in Africa. Nonetheless, the understanding of the organizational dynamics of small-scale miners' activities is modest. The paper outlines the small-scale mining codes in Tanzania and contrasts them to prevalent...... organizational practices in two Tanzanian small-scale mining settlements. It is argued that there is a need to adjust the regulatory mechanisms to well-consolidated practices: If basic practices differ substantially from official prescriptions of the mining codes over an extended period of time, certain elements...... manoeuvring of local small-scale mining operators and the reasons for the variations are essential to understand for policymakers and development practitioners. By incorporating prevalent practices and context-dependent variations in some of the crucial organizational components, it is possible to design...

  11. HUBUNGAN RETURN SAHAM DAN INFLASI DI INDONESIA

    Directory of Open Access Journals (Sweden)

    Nyoman Triaryati

    2017-03-01

    Full Text Available The effect of inflation to the stock return research had been held since three decades ago based on GeneralizeFisher’s Hypotheses, but ‘how inflation influenced stock return’ had become a debate until today. In Indonesiamost of the related research used inflation as one of the variables that influenced stock return despite of others inshort period of time. This research investigated the effect of inflation to the stock return in Indonesia within fifteenyears, which was divided into 3 (three periods of time reflecting different economic growth for each of it. Thepurpose of this allotment was to see the consistency how inflation influenced the stock market. Using a secondarydata from monthly inflation and IHSG period 1998 until 2012, included three hundred and sixty observation,simple regression model analyses was applied. This research acknowledged that inflation negatively influencedstock return in a long time period, but it did not exist in the short time period, except when the level of inflationreached 10%. In conclusion, inflation influence on the stock return was not ascertained by how long the investigationwas held but if there was any inflation rate reaching 10% within the period of investigation.

  12. Pengaruh Capital Adequacy Ratio (CAR, Beban Operasional Pendapatan Operasional (BOPO, Return on Asset (ROA dan Net Interest Margin (NIM terhadap Financing Deposit Ratio (FRD di PT. BPRS Bhakti Sumekar Sumenep (Periode 2011-2015

    Directory of Open Access Journals (Sweden)

    Cholida Noerainon

    2016-06-01

    Full Text Available The Bank is an industry whose business activities relying on public confidence so that the health of banks is done by maintaining the quality so that the bank can meet its obligations and maintain its performance. The purpose bank will be realized if the bank is able to significantly improve their performance optimal. To be able to function properly, the banks should have enough capital, maintaining its asset quality with a good, well-managed and operated by the precautionary principle thus generate enough profit to maintain the continuity of its business and maintain its liquidity so that it can meet its obligations at any time. the purpose of this study is the first: To determine the effect of the Capital Adequacy Ratio (CAR, Operating Expenses Towards Operating Income (OEOI, Return on Assets (ROA and Net Interest Margin (NIM simultaneously to the Financial to Deposit Ratio (FDR PT. BPRS Bhakti Sumekar Sumenep. Second: To determine the effect of the Capital Adequacy Ratio (CAR, Operating Expenses Towards Operating Income  (OEOI, Return on Assets (ROA and Net Interest Margin (NIM partially on Financial to Deposit Ratio (FDR PT. BPRS Bhakti Sumekar Sumenep. Third: To determine which variables are the most dominant influencing on Financial to Deposit Ratio (FDR at PT. BPRS Bhakti Sumekar Sumenep. In this research uses quantitative methods with the technique of multiple linear regression analysis with the help of SPSS analysis tools, while proving the hypothesis using a calculation T test and F test. The data used is secondary data namely quarterly publication report documentation results. The research results shows that the variables CAR, OEOI, ROA and NIM simultaneously no effect  towards FDR PT. BPRS Bhakti Sumekar Sumenep because Sig. > 0.05 and the value of Fcount

  13. Uncertainty and measurement

    International Nuclear Information System (INIS)

    Landsberg, P.T.

    1990-01-01

    This paper explores how the quantum mechanics uncertainty relation can be considered to result from measurements. A distinction is drawn between the uncertainties obtained by scrutinising experiments and the standard deviation type of uncertainty definition used in quantum formalism. (UK)

  14. Oil Volatility Risk and Expected Stock Returns

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Pan, Xuhui (Nick)

    After the financialization of commodity futures markets in 2004-05 oil volatility has become a strong predictor of returns and volatility of the overall stock market. Furthermore, stocks' exposure to oil volatility risk now drives the cross-section of expected returns. The difference in average...... return between the quintile of stocks with low exposure and high exposure to oil volatility is significant at 0.66% per month, and oil volatility risk carries a significant risk premium of -0.60% per month. In the post-financialization period, oil volatility risk is strongly related with various measures...

  15. A Perishable Inventory Model with Return

    Science.gov (United States)

    Setiawan, S. W.; Lesmono, D.; Limansyah, T.

    2018-04-01

    In this paper, we develop a mathematical model for a perishable inventory with return by assuming deterministic demand and inventory dependent demand. By inventory dependent demand, it means that demand at certain time depends on the available inventory at that time with certain rate. In dealing with perishable items, we should consider deteriorating rate factor that corresponds to the decreasing quality of goods. There are also costs involved in this model such as purchasing, ordering, holding, shortage (backordering) and returning costs. These costs compose the total costs in the model that we want to minimize. In the model we seek for the optimal return time and order quantity. We assume that after some period of time, called return time, perishable items can be returned to the supplier at some returning costs. The supplier will then replace them in the next delivery. Some numerical experiments are given to illustrate our model and sensitivity analysis is performed as well. We found that as the deteriorating rate increases, returning time becomes shorter, the optimal order quantity and total cost increases. When considering the inventory-dependent demand factor, we found that as this factor increases, assuming a certain deteriorating rate, returning time becomes shorter, optimal order quantity becomes larger and the total cost increases.

  16. Confronting dynamics and uncertainty in optimal decision making for conservation

    Science.gov (United States)

    Williams, Byron K.; Johnson, Fred A.

    2013-06-01

    The effectiveness of conservation efforts ultimately depends on the recognition that decision making, and the systems that it is designed to affect, are inherently dynamic and characterized by multiple sources of uncertainty. To cope with these challenges, conservation planners are increasingly turning to the tools of decision analysis, especially dynamic optimization methods. Here we provide a general framework for optimal, dynamic conservation and then explore its capacity for coping with various sources and degrees of uncertainty. In broadest terms, the dynamic optimization problem in conservation is choosing among a set of decision options at periodic intervals so as to maximize some conservation objective over the planning horizon. Planners must account for immediate objective returns, as well as the effect of current decisions on future resource conditions and, thus, on future decisions. Undermining the effectiveness of such a planning process are uncertainties concerning extant resource conditions (partial observability), the immediate consequences of decision choices (partial controllability), the outcomes of uncontrolled, environmental drivers (environmental variation), and the processes structuring resource dynamics (structural uncertainty). Where outcomes from these sources of uncertainty can be described in terms of probability distributions, a focus on maximizing the expected objective return, while taking state-specific actions, is an effective mechanism for coping with uncertainty. When such probability distributions are unavailable or deemed unreliable, a focus on maximizing robustness is likely to be the preferred approach. Here the idea is to choose an action (or state-dependent policy) that achieves at least some minimum level of performance regardless of the (uncertain) outcomes. We provide some examples of how the dynamic optimization problem can be framed for problems involving management of habitat for an imperiled species, conservation of a

  17. Confronting dynamics and uncertainty in optimal decision making for conservation

    Science.gov (United States)

    Williams, Byron K.; Johnson, Fred A.

    2013-01-01

    The effectiveness of conservation efforts ultimately depends on the recognition that decision making, and the systems that it is designed to affect, are inherently dynamic and characterized by multiple sources of uncertainty. To cope with these challenges, conservation planners are increasingly turning to the tools of decision analysis, especially dynamic optimization methods. Here we provide a general framework for optimal, dynamic conservation and then explore its capacity for coping with various sources and degrees of uncertainty. In broadest terms, the dynamic optimization problem in conservation is choosing among a set of decision options at periodic intervals so as to maximize some conservation objective over the planning horizon. Planners must account for immediate objective returns, as well as the effect of current decisions on future resource conditions and, thus, on future decisions. Undermining the effectiveness of such a planning process are uncertainties concerning extant resource conditions (partial observability), the immediate consequences of decision choices (partial controllability), the outcomes of uncontrolled, environmental drivers (environmental variation), and the processes structuring resource dynamics (structural uncertainty). Where outcomes from these sources of uncertainty can be described in terms of probability distributions, a focus on maximizing the expected objective return, while taking state-specific actions, is an effective mechanism for coping with uncertainty. When such probability distributions are unavailable or deemed unreliable, a focus on maximizing robustness is likely to be the preferred approach. Here the idea is to choose an action (or state-dependent policy) that achieves at least some minimum level of performance regardless of the (uncertain) outcomes. We provide some examples of how the dynamic optimization problem can be framed for problems involving management of habitat for an imperiled species, conservation of a

  18. Confronting dynamics and uncertainty in optimal decision making for conservation

    International Nuclear Information System (INIS)

    Williams, Byron K; Johnson, Fred A

    2013-01-01

    The effectiveness of conservation efforts ultimately depends on the recognition that decision making, and the systems that it is designed to affect, are inherently dynamic and characterized by multiple sources of uncertainty. To cope with these challenges, conservation planners are increasingly turning to the tools of decision analysis, especially dynamic optimization methods. Here we provide a general framework for optimal, dynamic conservation and then explore its capacity for coping with various sources and degrees of uncertainty. In broadest terms, the dynamic optimization problem in conservation is choosing among a set of decision options at periodic intervals so as to maximize some conservation objective over the planning horizon. Planners must account for immediate objective returns, as well as the effect of current decisions on future resource conditions and, thus, on future decisions. Undermining the effectiveness of such a planning process are uncertainties concerning extant resource conditions (partial observability), the immediate consequences of decision choices (partial controllability), the outcomes of uncontrolled, environmental drivers (environmental variation), and the processes structuring resource dynamics (structural uncertainty). Where outcomes from these sources of uncertainty can be described in terms of probability distributions, a focus on maximizing the expected objective return, while taking state-specific actions, is an effective mechanism for coping with uncertainty. When such probability distributions are unavailable or deemed unreliable, a focus on maximizing robustness is likely to be the preferred approach. Here the idea is to choose an action (or state-dependent policy) that achieves at least some minimum level of performance regardless of the (uncertain) outcomes. We provide some examples of how the dynamic optimization problem can be framed for problems involving management of habitat for an imperiled species, conservation of a

  19. Lidar 2009 - All Returns

    Data.gov (United States)

    Kansas Data Access and Support Center — LIDAR-derived binary (.las) files containing classified points of all returns. We have 3 classifications Unclassified, Ground, Low points. The average Ground Sample...

  20. Uncertain programming models for portfolio selection with uncertain returns

    Science.gov (United States)

    Zhang, Bo; Peng, Jin; Li, Shengguo

    2015-10-01

    In an indeterminacy economic environment, experts' knowledge about the returns of securities consists of much uncertainty instead of randomness. This paper discusses portfolio selection problem in uncertain environment in which security returns cannot be well reflected by historical data, but can be evaluated by the experts. In the paper, returns of securities are assumed to be given by uncertain variables. According to various decision criteria, the portfolio selection problem in uncertain environment is formulated as expected-variance-chance model and chance-expected-variance model by using the uncertainty programming. Within the framework of uncertainty theory, for the convenience of solving the models, some crisp equivalents are discussed under different conditions. In addition, a hybrid intelligent algorithm is designed in the paper to provide a general method for solving the new models in general cases. At last, two numerical examples are provided to show the performance and applications of the models and algorithm.

  1. The uncertainties in estimating measurement uncertainties

    International Nuclear Information System (INIS)

    Clark, J.P.; Shull, A.H.

    1994-01-01

    All measurements include some error. Whether measurements are used for accountability, environmental programs or process support, they are of little value unless accompanied by an estimate of the measurements uncertainty. This fact is often overlooked by the individuals who need measurements to make decisions. This paper will discuss the concepts of measurement, measurements errors (accuracy or bias and precision or random error), physical and error models, measurement control programs, examples of measurement uncertainty, and uncertainty as related to measurement quality. Measurements are comparisons of unknowns to knowns, estimates of some true value plus uncertainty; and are no better than the standards to which they are compared. Direct comparisons of unknowns that match the composition of known standards will normally have small uncertainties. In the real world, measurements usually involve indirect comparisons of significantly different materials (e.g., measuring a physical property of a chemical element in a sample having a matrix that is significantly different from calibration standards matrix). Consequently, there are many sources of error involved in measurement processes that can affect the quality of a measurement and its associated uncertainty. How the uncertainty estimates are determined and what they mean is as important as the measurement. The process of calculating the uncertainty of a measurement itself has uncertainties that must be handled correctly. Examples of chemistry laboratory measurement will be reviewed in this report and recommendations made for improving measurement uncertainties

  2. Precipitation intensity-duration-frequency curves and their uncertainties for Ghaap plateau

    Directory of Open Access Journals (Sweden)

    C.M. Tfwala

    2017-01-01

    Full Text Available Engineering infrastructures such as stormwater drains and bridges are commonly designed using the concept of Intensity-Duration-Frequency (IDF curves, which assume that the occurrence of precipitation patterns and distributions are spatially similar within the drainage area and remain unchanged throughout the lifespan of the infrastructures (stationary. Based on the premise that climate change will alter the spatial and temporal variability of precipitation patterns, inaccuracy in the estimation of IDF curves may occur. As such, prior to developing IDF curves, it is crucial to analyse trends of annual precipitation maxima. The objective of this study was to estimate the precipitation intensities and their uncertainties (lower and upper limits for durations of 0.125, 0.25, 0.5, 1, 2, 4, and 6 h and return periods of 2, 10, 25, 50 and 100 years in the Ghaap plateau, Northern Cape Province, South Africa using the Generalized Extreme Value (GEV distribution. The annual precipitation maxima were extracted from long-term (1918–2014 precipitation data for four meteorological stations (Postmasburg, Douglas, Kuruman and Groblershoop sourced from the South African Weather Services (SAWS. On average, the estimated extreme precipitation intensities for the plateau ranged from 4.2 mm/h for 6 h storm duration to 55.8 mm/h for 0.125 h at 2 years return period. At 100 year return period, the intensity ranged from 13.3 mm/h for 6 h duration to 175.5 mm/h for the duration of 0.125 h. The lower limit of uncertainty ranged from 11.7% at 2 years return period to 26% at 100 year return period, and from 12.8% to 58.4% for the upper limit for the respective return periods. This methodology can be integrated into policy formulation for the design of stormwater and flood management infrastructures in the Ghaap plateau, where mining is the main economic activity.

  3. Uncertainty in social dilemmas

    OpenAIRE

    Kwaadsteniet, Erik Willem de

    2007-01-01

    This dissertation focuses on social dilemmas, and more specifically, on environmental uncertainty in these dilemmas. Real-life social dilemma situations are often characterized by uncertainty. For example, fishermen mostly do not know the exact size of the fish population (i.e., resource size uncertainty). Several researchers have therefore asked themselves the question as to how such uncertainty influences people’s choice behavior. These researchers have repeatedly concluded that uncertainty...

  4. Analysis of uncertainties in a probabilistic seismic hazard estimation, example for France

    International Nuclear Information System (INIS)

    Beauval, C.

    2003-12-01

    This thesis proposes a new methodology that allows to pinpoint the key parameters that control probabilistic seismic hazard assessment (PSHA) and at the same time to quantify the impact of these parameters uncertainties on hazard estimates. Cornell-McGuire's method is used here. First, uncertainties on magnitude and location determinations are modeled and quantified: resulting variability on hazard estimates ranges between 5% and 25% (=COV), depending on the site and the return period. An impact study is then performed, in order to determine the hierarchy between the impacts on hazard of the choices of four other parameters: intensity-magnitude correlation, minimum and maximum magnitudes, the truncation of the attenuation relationship. The results at 34 Hz (PGA) indicate that the maximum magnitude is the less influent parameter (from 100 to 10000 years); whereas the intensity-magnitude correlation and the truncation of ground motion predictions (>2σ) are the controlling parameters at all return periods (up to 30% decrease each at 10000 years). An increase in the minimum magnitude contributing to the hazard, from 3.5 to 4.5, can also produce non-negligible impacts at small return periods (up to 20% decrease of hazard results at 475 years). Finally, the overall variability on hazard estimates due to the combined choices of the four parameters can reach up to 30% (COV, at 34 Hz). For lower frequencies (<5 Hz), the overall variability increases and maximum magnitude becomes a controlling parameter. Therefore, variability of estimates due to catalog uncertainties and to the choices of these four parameters must be taken into account in all probabilistic seismic hazard studies in France. To reduce variability in hazard estimates, future research should concentrate on the elaboration of an appropriate intensity- magnitude correlation, as well as on a more realistic way of taking into account ground motion dispersion. (author)

  5. Investment Strategy Based on Aviation Accidents: Are there abnormal returns?

    Directory of Open Access Journals (Sweden)

    Marcos Rosa Costa

    2013-06-01

    Full Text Available This article investigates whether an investment strategy based on aviation accidents can generate abnormal returns. We performed an event study considering all the aviation accidents with more than 10 fatalities in the period from 1998 to 2009 and the stock market performance of the respective airlines and aircraft manufacturers in the days after the event. The tests performed were based on the model of Campbell, Lo & MacKinlay (1997 for definition of abnormal returns, by means of linear regression between the firms’ stock returns and the return of a market portfolio used as a benchmark. This enabled projecting the expected future returns of the airlines and aircraft makers, for comparison with the observed returns after each event. The result obtained suggests that an investment strategy based on aviation accidents is feasible because abnormal returns can be obtained in the period immediately following an aviation disaster.

  6. Uncertainty analysis in safety assessment

    Energy Technology Data Exchange (ETDEWEB)

    Lemos, Francisco Luiz de [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil); Sullivan, Terry [Brookhaven National Lab., Upton, NY (United States)

    1997-12-31

    Nuclear waste disposal is a very complex subject which requires the study of many different fields of science, like hydro geology, meteorology, geochemistry, etc. In addition, the waste disposal facilities are designed to last for a very long period of time. Both of these conditions make safety assessment projections filled with uncertainty. This paper addresses approaches for treatment of uncertainties in the safety assessment modeling due to the variability of data and some current approaches used to deal with this problem. (author) 13 refs.; e-mail: lemos at bnl.gov; sulliva1 at bnl.gov

  7. Inflation and Inflation Uncertainty in Turkey

    OpenAIRE

    dogru, bulent

    2014-01-01

    Abstract: In this study, the relationship between inflation and inflation uncertainty is analyzed using Granger causality tests with annual inflation series covering the time period 1923 to 2012 for Turkish Economy. Inflation uncertainty is measured by Exponential Generalized Autoregressive Conditional Heteroskedastic model. Econometric findings suggest that although in long run the Friedman's hypothesis that high inflation increases inflation ...

  8. The Reference Return Ratio

    DEFF Research Database (Denmark)

    Nicolaisen, Jeppe; Faber Frandsen, Tove

    2008-01-01

    The paper introduces a new journal impact measure called The Reference Return Ratio (3R). Unlike the traditional Journal Impact Factor (JIF), which is based on calculations of publications and citations, the new measure is based on calculations of bibliographic investments (references) and returns...... (citations). A comparative study of the two measures shows a strong relationship between the 3R and the JIF. Yet, the 3R appears to correct for citation habits, citation dynamics, and composition of document types - problems that typically are raised against the JIF. In addition, contrary to traditional...

  9. Return to nucleate boiling

    International Nuclear Information System (INIS)

    Shumway, R.W.

    1985-01-01

    This paper presents a collection of TMIN (temperature of return to nucleate boiling) correlations, evaluates them under several conditions, and compares them with a wide range of data. Purpose is to obtain the best one for use in a water reactor safety computer simulator known as TRAC-B. Return to nucleate boiling can occur in a reactor accident at either high or low pressure and flow rates. Most of the correlations yield unrealistic results under some conditions. A new correlation is proposed which overcomes many of the deficiencies

  10. Sustainable Mars Sample Return

    Science.gov (United States)

    Alston, Christie; Hancock, Sean; Laub, Joshua; Perry, Christopher; Ash, Robert

    2011-01-01

    The proposed Mars sample return mission will be completed using natural Martian resources for the majority of its operations. The system uses the following technologies: In-Situ Propellant Production (ISPP), a methane-oxygen propelled Mars Ascent Vehicle (MAV), a carbon dioxide powered hopper, and a hydrogen fueled balloon system (large balloons and small weather balloons). The ISPP system will produce the hydrogen, methane, and oxygen using a Sabatier reactor. a water electrolysis cell, water extracted from the Martian surface, and carbon dioxide extracted from the Martian atmosphere. Indigenous hydrogen will fuel the balloon systems and locally-derived methane and oxygen will fuel the MAV for the return of a 50 kg sample to Earth. The ISPP system will have a production cycle of 800 days and the estimated overall mission length is 1355 days from Earth departure to return to low Earth orbit. Combining these advanced technologies will enable the proposed sample return mission to be executed with reduced initial launch mass and thus be more cost efficient. The successful completion of this mission will serve as the next step in the advancement of Mars exploration technology.

  11. Return of qualified Sudanese

    OpenAIRE

    Lindsay T McMahon

    2007-01-01

    With the signing of the Comprehensive Peace Agreement in January 2005, the new Government of South Sudan began to call for the return of the millions of South Sudanese IDP s and refugees. The International Organization for Migration (IOM) has developed a programme to help them do so.

  12. Return of qualified Sudanese

    Directory of Open Access Journals (Sweden)

    Lindsay T McMahon

    2007-07-01

    Full Text Available With the signing of the Comprehensive Peace Agreement in January 2005, the new Government of South Sudan began to call for the return of the millions of South Sudanese IDP s and refugees. The International Organization for Migration (IOM has developed a programme to help them do so.

  13. Higher Education Endowments Return

    Science.gov (United States)

    Bahlmann, David; Walda, John D.; Sedlacek, Verne O.

    2012-01-01

    A new study of endowments by the National Association of College and University Business Officers (NACUBO) and the Commonfund Institute has brought good news to college and universities: While endowment returns dropped precipitously in fiscal year 2009 as a result of the financial crisis and accompanying slide in equity markets, they climbed to an…

  14. Return to Play

    Science.gov (United States)

    Mangan, Marianne

    2013-01-01

    Call it physical activity, call it games, or call it play. Whatever its name, it's a place we all need to return to. In the physical education, recreation, and dance professions, we need to redesign programs to address the need for and want of play that is inherent in all of us.

  15. Precipitation intensity-duration-frequency curves for central Belgium with an ensemble of EURO-CORDEX simulations, and associated uncertainties

    Science.gov (United States)

    Hosseinzadehtalaei, Parisa; Tabari, Hossein; Willems, Patrick

    2018-02-01

    An ensemble of 88 regional climate model (RCM) simulations at 0.11° and 0.44° spatial resolutions from the EURO-CORDEX project is analyzed for central Belgium to investigate the projected impact of climate change on precipitation intensity-duration-frequency (IDF) relationships and extreme precipitation quantiles typically used in water engineering designs. The rate of uncertainty arising from the choice of RCM, driving GCM, and radiative concentration pathway (RCP4.5 & RCP8.5) is quantified using a variance decomposition technique after reconstruction of missing data in GCM × RCM combinations. A comparative analysis between the historical simulations of the EURO-CORDEX 0.11° and 0.44° RCMs shows higher precipitation intensities by the finer resolution runs, leading to a larger overestimation of the observations-based IDFs by the 0.11° runs. The results reveal that making a temporal stationarity assumption for the climate system may lead to underestimation of precipitation quantiles up to 70% by the end of this century. This projected increase is generally larger for the 0.11° RCMs compared with the 0.44° RCMs. The relative changes in extreme precipitation do depend on return period and duration, indicating an amplification for larger return periods and for smaller durations. The variance decomposition approach generally identifies RCM as the most dominant component of uncertainty in changes of more extreme precipitation (return period of 10 years) for both 0.11° and 0.44° resolutions, followed by GCM and RCP scenario. The uncertainties associated with cross-contributions of RCMs, GCMs, and RCPs play a non-negligible role in the associated uncertainties of the changes.

  16. Bond return predictability in expansions and recessions

    DEFF Research Database (Denmark)

    Engsted, Tom; Møller, Stig Vinther; Jensen, Magnus David Sander

    We document that over the period 1953-2011 US bond returns are predictable in expansionary periods but unpredictable during recessions. This result holds in both in-sample and out-of-sample analyses and using both univariate regressions and combination forecasting techniques. A simulation study...... but negative in recessions. The results are also consistent with tests showing that the expectations hypothesis of the term structure holds in recessions but not in expansions. However, the results for bonds are in sharp contrast to results for stocks showing that stock returns are predictable in recessions...... but not in expansions. Thus, our results indicate that there is not a common predictive pattern of stock and bond returns associated with the state of the economy....

  17. Instrument uncertainty predictions

    International Nuclear Information System (INIS)

    Coutts, D.A.

    1991-07-01

    The accuracy of measurements and correlations should normally be provided for most experimental activities. The uncertainty is a measure of the accuracy of a stated value or equation. The uncertainty term reflects a combination of instrument errors, modeling limitations, and phenomena understanding deficiencies. This report provides several methodologies to estimate an instrument's uncertainty when used in experimental work. Methods are shown to predict both the pretest and post-test uncertainty

  18. Oil Volatility Risk and Expected Stock Returns

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Pan, Xuhui (Nick)

    return between the quintile of stocks with low exposure and high exposure to oil volatility is significant at 0.66% per month, and oil volatility risk carries a significant risk premium of -0.60% per month. In the post-financialization period, oil volatility risk is strongly related with various measures...

  19. The Returns on Investment Grade Diamonds

    NARCIS (Netherlands)

    Renneboog, L.D.R.

    2013-01-01

    Abstract: This paper examines the risk-return characteristics of investment grade gems (white diamonds, colored diamonds and other types of gems including sapphires, rubies, and emeralds). The transactions are coming from gem auctions and span the period 1999-2012. Over our time frame, the annual

  20. Integrated forward/reverse logistics network design under uncertainty with pricing for collection of used products

    DEFF Research Database (Denmark)

    Fattahi, Mohammad; Govindan, Kannan

    2017-01-01

    This paper addresses design and planning of an integrated forward/reverse logistics network over a planning horizon with multiple tactical periods. In the network, demand for new products and potential return of used products are stochastic. Furthermore, collection amounts of used products...... with different quality levels are assumed dependent on offered acquisition prices to customer zones. A uniform distribution function defines the expected price of each customer zone for one unit of each used product. Using two-stage stochastic programming, a mixed-integer linear programming model is proposed....... To cope with demand and potential return uncertainty, Latin Hypercube Sampling method is applied to generate fan of scenarios and then, backward scenario reduction technique is used to reduce the number of scenarios. Due to the problem complexity, a novel simulation-based simulated annealing algorithm...

  1. Uncertainties Related to Extreme Event Statistics of Sewer System Surcharge and Overflow

    DEFF Research Database (Denmark)

    Schaarup-Jensen, Kjeld; Johansen, C.; Thorndahl, Søren Liedtke

    2005-01-01

    Today it is common practice - in the major part of Europe - to base design of sewer systems in urban areas on recommended minimum values of flooding frequencies related to either pipe top level, basement level in buildings or level of road surfaces. Thus storm water runoff in sewer systems is only...... proceeding in an acceptable manner, if flooding of these levels is having an average return period bigger than a predefined value. This practice is also often used in functional analysis of existing sewer systems. If a sewer system can fulfil recommended flooding frequencies or not, can only be verified...... by performing long term simulations - using a sewer flow simulation model - and draw up extreme event statistics from the model simulations. In this context it is important to realize that uncertainties related to the input parameters of rainfall runoff models will give rise to uncertainties related...

  2. Investment choice under uncertainty: A review essay

    Directory of Open Access Journals (Sweden)

    Trifunović Dejan

    2005-01-01

    Full Text Available An investment opportunity whose return is perfectly predictable, hardly exists at all. Instead, investor makes his decisions under conditions of uncertainty. Theory of expected utility is the main analytical tool for description of choice under uncertainty. Critics of the theory contend that individuals have bounded rationality and that the theory of expected utility is not correct. When agents are faced with risky decisions they behave differently, conditional on their attitude towards risk. They can be risk loving, risk averse or risk neutral. In order to make an investment decision it is necessary to compare probability distribution functions of returns. Investment decision making is much simpler if one uses expected values and variances instead of probability distribution functions.

  3. Product return management

    DEFF Research Database (Denmark)

    Shaharudin, Mohd Rizaimy; Govindan, Kannan; Zailani, Suhaiza

    2017-01-01

    The aim of this study is to examine the extent to which product returns motivate manufacturing firms to adopt closed-loop supply chain activities that influence the effectiveness of reverse supply chains. The hypotheses have been tested using data from a sample of 150 environmental management...... system ISO 14001 certified manufacturing firms in Malaysia through the census sampling approach. The results of the empirical test using LISREL Version 8.70 for the structural equation modeling support the fundamental explanation of the influence of the institutional forces towards the adoption of closed...... eventually impacts the firm's effectiveness in the reverse supply chain. The findings also help managers to understand the factors that can improve the outcome of the adoption of closed-loop supply chain activities by intensifying the extent of involvement in product returns, which provides a valuable...

  4. Volatility return intervals analysis of the Japanese market

    Science.gov (United States)

    Jung, W.-S.; Wang, F. Z.; Havlin, S.; Kaizoji, T.; Moon, H.-T.; Stanley, H. E.

    2008-03-01

    We investigate scaling and memory effects in return intervals between price volatilities above a certain threshold q for the Japanese stock market using daily and intraday data sets. We find that the distribution of return intervals can be approximated by a scaling function that depends only on the ratio between the return interval τ and its mean . We also find memory effects such that a large (or small) return interval follows a large (or small) interval by investigating the conditional distribution and mean return interval. The results are similar to previous studies of other markets and indicate that similar statistical features appear in different financial markets. We also compare our results between the period before and after the big crash at the end of 1989. We find that scaling and memory effects of the return intervals show similar features although the statistical properties of the returns are different.

  5. No Refund or Full Refund: When Should a Fashion Brand Offer Full Refund Consumer Return Service for Mass Customization Products?

    OpenAIRE

    Choi, Tsan-Ming; Liu, Na; Ren, Shuyun; Hui, Chi-Leung

    2013-01-01

    We analytically explore in this paper the consumer return policy under fashion mass customization (MC) program. To be specific, we model the stochastic fashion MC program with the consideration of consumer demand uncertainty. If a consumer return policy is implemented, we further consider return uncertainty. By modeling the optimization objective of the risk averse MC fashion brand via a mean-variance approach, we derive the closed-form optimal solution under each case. We then conduct both a...

  6. Critical loads - assessment of uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    Barkman, A.

    1998-10-01

    The effects of data uncertainty in applications of the critical loads concept were investigated on different spatial resolutions in Sweden and northern Czech Republic. Critical loads of acidity (CL) were calculated for Sweden using the biogeochemical model PROFILE. Three methods with different structural complexity were used to estimate the adverse effects of S0{sub 2} concentrations in northern Czech Republic. Data uncertainties in the calculated critical loads/levels and exceedances (EX) were assessed using Monte Carlo simulations. Uncertainties within cumulative distribution functions (CDF) were aggregated by accounting for the overlap between site specific confidence intervals. Aggregation of data uncertainties within CDFs resulted in lower CL and higher EX best estimates in comparison with percentiles represented by individual sites. Data uncertainties were consequently found to advocate larger deposition reductions to achieve non-exceedance based on low critical loads estimates on 150 x 150 km resolution. Input data were found to impair the level of differentiation between geographical units at all investigated resolutions. Aggregation of data uncertainty within CDFs involved more constrained confidence intervals for a given percentile. Differentiation as well as identification of grid cells on 150 x 150 km resolution subjected to EX was generally improved. Calculation of the probability of EX was shown to preserve the possibility to differentiate between geographical units. Re-aggregation of the 95%-ile EX on 50 x 50 km resolution generally increased the confidence interval for each percentile. Significant relationships were found between forest decline and the three methods addressing risks induced by S0{sub 2} concentrations. Modifying S0{sub 2} concentrations by accounting for the length of the vegetation period was found to constitute the most useful trade-off between structural complexity, data availability and effects of data uncertainty. Data

  7. Uncertainty analysis guide

    International Nuclear Information System (INIS)

    Andres, T.H.

    2002-05-01

    This guide applies to the estimation of uncertainty in quantities calculated by scientific, analysis and design computer programs that fall within the scope of AECL's software quality assurance (SQA) manual. The guide weaves together rational approaches from the SQA manual and three other diverse sources: (a) the CSAU (Code Scaling, Applicability, and Uncertainty) evaluation methodology; (b) the ISO Guide,for the Expression of Uncertainty in Measurement; and (c) the SVA (Systems Variability Analysis) method of risk analysis. This report describes the manner by which random and systematic uncertainties in calculated quantities can be estimated and expressed. Random uncertainty in model output can be attributed to uncertainties of inputs. The propagation of these uncertainties through a computer model can be represented in a variety of ways, including exact calculations, series approximations and Monte Carlo methods. Systematic uncertainties emerge from the development of the computer model itself, through simplifications and conservatisms, for example. These must be estimated and combined with random uncertainties to determine the combined uncertainty in a model output. This report also addresses the method by which uncertainties should be employed in code validation, in order to determine whether experiments and simulations agree, and whether or not a code satisfies the required tolerance for its application. (author)

  8. Uncertainty analysis guide

    Energy Technology Data Exchange (ETDEWEB)

    Andres, T.H

    2002-05-01

    This guide applies to the estimation of uncertainty in quantities calculated by scientific, analysis and design computer programs that fall within the scope of AECL's software quality assurance (SQA) manual. The guide weaves together rational approaches from the SQA manual and three other diverse sources: (a) the CSAU (Code Scaling, Applicability, and Uncertainty) evaluation methodology; (b) the ISO Guide,for the Expression of Uncertainty in Measurement; and (c) the SVA (Systems Variability Analysis) method of risk analysis. This report describes the manner by which random and systematic uncertainties in calculated quantities can be estimated and expressed. Random uncertainty in model output can be attributed to uncertainties of inputs. The propagation of these uncertainties through a computer model can be represented in a variety of ways, including exact calculations, series approximations and Monte Carlo methods. Systematic uncertainties emerge from the development of the computer model itself, through simplifications and conservatisms, for example. These must be estimated and combined with random uncertainties to determine the combined uncertainty in a model output. This report also addresses the method by which uncertainties should be employed in code validation, in order to determine whether experiments and simulations agree, and whether or not a code satisfies the required tolerance for its application. (author)

  9. Entrepreneurship: Origins and Returns

    OpenAIRE

    Berglann, Helge; R. Moen, Espen R.; Røed, Knut; Skogstrøm, Jens Fredrik

    2010-01-01

    We examine the origins and outcome of entrepreneurship on the basis of exceptionally comprehensive Norwegian matched worker-firm-owner data. In contrast to most existing studies, our notion of entrepreneurship not only comprises self-employment, but also employment in partly self-owned limited liability firms. Based on this extended entrepreneurship concept, we find that entrepreneurship tends to be profitable. It also raises in-come uncertainty, but the most successful quartile gains much mo...

  10. Uncertainty and Cognitive Control

    Directory of Open Access Journals (Sweden)

    Faisal eMushtaq

    2011-10-01

    Full Text Available A growing trend of neuroimaging, behavioural and computational research has investigated the topic of outcome uncertainty in decision-making. Although evidence to date indicates that humans are very effective in learning to adapt to uncertain situations, the nature of the specific cognitive processes involved in the adaptation to uncertainty are still a matter of debate. In this article, we reviewed evidence suggesting that cognitive control processes are at the heart of uncertainty in decision-making contexts. Available evidence suggests that: (1 There is a strong conceptual overlap between the constructs of uncertainty and cognitive control; (2 There is a remarkable overlap between the neural networks associated with uncertainty and the brain networks subserving cognitive control; (3 The perception and estimation of uncertainty might play a key role in monitoring processes and the evaluation of the need for control; (4 Potential interactions between uncertainty and cognitive control might play a significant role in several affective disorders.

  11. Does Exposure to Returning SEN Students Harm Peers’ Outcomes?

    DEFF Research Database (Denmark)

    Rangvid, Beatrice Schindler

    Returning SEN (special educational needs) students from segregated settings to regular class rooms may have spill-over effects on their peers. Using a combination of survey data and data from administrative registers from Denmark, I investigate whether becoming exposed to returning SEN students a...... themselves finds that while reading results are unaffected, returners experience large improvements in math achievement of roughly 65% of a standard deviation over a three year period. Intermediate and advanced math skills are more affected than basic skills....

  12. INSTITUTIONAL OWNERSHIP LEVEL AND RISK-ADJUSTED RETURN

    OpenAIRE

    Isaiah, Chioma; Li, Meng (Emma)

    2017-01-01

    This paper examines the relationship between the level of institutional ownership andrisk-adjusted return on stocks. We find a significant positive relationship between the level ofinstitutional ownership on a stock and its risk-adjusted return. This result holds both in the longrun and in shorter time periods. Our findings suggest that all things being equal, it is possible toobtain risk-adjusted return by going short on the stocks with low institutional ownership andgoing long on those with...

  13. Robust Adaptation? Assessing the sensitivity of safety margins in flood defences to uncertainty in future simulations - a case study from Ireland.

    Science.gov (United States)

    Murphy, Conor; Bastola, Satish; Sweeney, John

    2013-04-01

    associated with such return periods. Sensitivity results show that the impact of climate change is not as great for flood peaks with higher return periods. The average width of the uncertainty range and the size of the range for each catchment reveals that the uncertainties in low frequency events are greater than high frequency events. In addition, the uncertainty interval, estimated as the average width of the uncertainty range of flow for the five return periods, grows wider with a decrease in the runoff coefficient and wetness index of each catchment, both of which tend to increase the nonlinearity in the rainfall response. A key management question that emerges is the acceptability of residual risk where high exposure of vulnerable populations and/or critical infrastructure coincide with high costs of additional capacity in safety margins.

  14. Uncertainties in Forecasting Streamflow using Entropy Theory

    Science.gov (United States)

    Cui, H.; Singh, V. P.

    2017-12-01

    Streamflow forecasting is essential in river restoration, reservoir operation, power generation, irrigation, navigation, and water management. However, there is always uncertainties accompanied in forecast, which may affect the forecasting results and lead to large variations. Therefore, uncertainties must be considered and be assessed properly when forecasting streamflow for water management. The aim of our work is to quantify the uncertainties involved in forecasting streamflow and provide reliable streamflow forecast. Despite that streamflow time series are stochastic, they exhibit seasonal and periodic patterns. Therefore, streamflow forecasting entails modeling seasonality, periodicity, and its correlation structure, and assessing uncertainties. This study applies entropy theory to forecast streamflow and measure uncertainties during the forecasting process. To apply entropy theory for streamflow forecasting, spectral analysis is combined to time series analysis, as spectral analysis can be employed to characterize patterns of streamflow variation and identify the periodicity of streamflow. That is, it permits to extract significant information for understanding the streamflow process and prediction thereof. Application of entropy theory for streamflow forecasting involves determination of spectral density, determination of parameters, and extension of autocorrelation function. The uncertainties brought by precipitation input, forecasting model and forecasted results are measured separately using entropy. With information theory, how these uncertainties transported and aggregated during these processes will be described.

  15. Cost Efficiency and Returns to Scope in Italian Investment Firms

    OpenAIRE

    Marcello Basili; Fulvio Fontini

    2005-01-01

    This paper estimates cost efficiency and returns to scope of Italian investment firms during the period 1998-2002, following the stochastic frontier function approach. Results indicate a large inefficiency for Italian investment firms (with a high standard deviation across sample) and the absence of significant returns to scope

  16. Macro factors in oil futures returns

    International Nuclear Information System (INIS)

    Le Pen, Yannick; Sevi, Benoit

    2012-01-01

    We investigate the macro factors that can explain the monthly oil futures return for the NYMEX WTI futures contract for the time period 1993:11 to 2010:03. We build a new database of 187 real and nominal macro-economic variables from developed and emerging countries and resort to the large factor approximate model to extract 9 factors from this dataset. We then regress crude oil return on several combinations of these factors. Our best model explains around 38% of the variability of oil futures return. More interestingly, the factor which has the largest influence on crude oil price is related to real variables from emerging countries. This result confirms the latest finding in the literature that the recent evolution in oil price is attributable to change in supply and demand conditions and not to the large increase in trading activity from speculators. (authors)

  17. Mars Sample Return Architecture Overview

    Science.gov (United States)

    Edwards, C. D.; Vijendran, S.

    2018-04-01

    NASA and ESA are exploring potential concepts for a Sample Retrieval Lander and Earth Return Orbiter that could return samples planned to be collected and cached by the Mars 2020 rover mission. We provide an overview of the Mars Sample Return architecture.

  18. Uncertainty of dustfall monitoring results

    Directory of Open Access Journals (Sweden)

    Martin A. van Nierop

    2017-06-01

    Full Text Available Fugitive dust has the ability to cause a nuisance and pollute the ambient environment, particularly from human activities including construction and industrial sites and mining operations. As such, dustfall monitoring has occurred for many decades in South Africa; little has been published on the repeatability, uncertainty, accuracy and precision of dustfall monitoring. Repeatability assesses the consistency associated with the results of a particular measurement under the same conditions; the consistency of the laboratory is assessed to determine the uncertainty associated with dustfall monitoring conducted by the laboratory. The aim of this study was to improve the understanding of the uncertainty in dustfall monitoring; thereby improving the confidence in dustfall monitoring. Uncertainty of dustfall monitoring was assessed through a 12-month study of 12 sites that were located on the boundary of the study area. Each site contained a directional dustfall sampler, which was modified by removing the rotating lid, with four buckets (A, B, C and D installed. Having four buckets on one stand allows for each bucket to be exposed to the same conditions, for the same period of time; therefore, should have equal amounts of dust deposited in these buckets. The difference in the weight (mg of the dust recorded from each bucket at each respective site was determined using the American Society for Testing and Materials method D1739 (ASTM D1739. The variability of the dust would provide the confidence level of dustfall monitoring when reporting to clients.

  19. DS02 uncertainty analysis

    International Nuclear Information System (INIS)

    Kaul, Dean C.; Egbert, Stephen D.; Woolson, William A.

    2005-01-01

    In order to avoid the pitfalls that so discredited DS86 and its uncertainty estimates, and to provide DS02 uncertainties that are both defensible and credible, this report not only presents the ensemble uncertainties assembled from uncertainties in individual computational elements and radiation dose components but also describes how these relate to comparisons between observed and computed quantities at critical intervals in the computational process. These comparisons include those between observed and calculated radiation free-field components, where observations include thermal- and fast-neutron activation and gamma-ray thermoluminescence, which are relevant to the estimated systematic uncertainty for DS02. The comparisons also include those between calculated and observed survivor shielding, where the observations consist of biodosimetric measurements for individual survivors, which are relevant to the estimated random uncertainty for DS02. (J.P.N.)

  20. Investment and uncertainty in the international oil and gas industry

    International Nuclear Information System (INIS)

    Mohn, Klaus; Misund, Baard

    2009-01-01

    The standard theory of irreversible investments and real options suggests a negative relation between investment and uncertainty. Richer models with compound option structures open for a positive relationship. This paper presents a micro-econometric study of corporate investment and uncertainty in a period of market turbulence and restructuring in the international oil and gas industry. Based on data for 115 companies over the period 1992-2005, we estimate four different specifications of the q model of investment, with robust results for the uncertainty variables. The estimated models suggest that macroeconomic uncertainty creates a bottleneck for oil and gas investment and production, whereas industry-specific uncertainty has a stimulating effect. (author)

  1. Design of Demand Driven Return Supply Chain for High-Tech Products

    NARCIS (Netherlands)

    Ashayeri, J.; Tuzkaya, G.

    2010-01-01

    Many high-tech supply chain operate in a context of high process and market uncertainties due to shorter product life cycles. When introducing a new product, a company must manage the cost of supply, including the cost of returns over its short life cycle. The returns distribution looks like a

  2. Model uncertainty and probability

    International Nuclear Information System (INIS)

    Parry, G.W.

    1994-01-01

    This paper discusses the issue of model uncertainty. The use of probability as a measure of an analyst's uncertainty as well as a means of describing random processes has caused some confusion, even though the two uses are representing different types of uncertainty with respect to modeling a system. The importance of maintaining the distinction between the two types is illustrated with a simple example

  3. The cost of uncertainty in capacity expansion problems

    Energy Technology Data Exchange (ETDEWEB)

    Jenhung Wang [National Chung Cheng Univ., Dept. of Business Administration, Chia-Yi (Taiwan); Sparrow, F.T. [Purdue Univ., School of Industrial Engineering, West Lafayette, IN (United States)

    1999-07-01

    The goals of this paper are to present a two-stage programming model of the capacity expansion problem under uncertainty of demand and explore the impact of the uncertainty on cost. The model is a mixed integer nonlinear programming (MINLP) model with the consideration of uncertainty used to maximise the expected presented value of utility profits over the planning horizon, under the constraints of rate of return and reserve margin regulation. The results reveal that the uncertainty harms the profit seriously. In this paper both microeconomics and mathematical programming are used to analyse the problem. We try to observe the economic behaviour of the utility with uncertainty involved. We also investigate the influence on the cost of uncertainty of each economic parameter. (Author)

  4. Uncertainty in artificial intelligence

    CERN Document Server

    Kanal, LN

    1986-01-01

    How to deal with uncertainty is a subject of much controversy in Artificial Intelligence. This volume brings together a wide range of perspectives on uncertainty, many of the contributors being the principal proponents in the controversy.Some of the notable issues which emerge from these papers revolve around an interval-based calculus of uncertainty, the Dempster-Shafer Theory, and probability as the best numeric model for uncertainty. There remain strong dissenting opinions not only about probability but even about the utility of any numeric method in this context.

  5. Uncertainties in hydrogen combustion

    International Nuclear Information System (INIS)

    Stamps, D.W.; Wong, C.C.; Nelson, L.S.

    1988-01-01

    Three important areas of hydrogen combustion with uncertainties are identified: high-temperature combustion, flame acceleration and deflagration-to-detonation transition, and aerosol resuspension during hydrogen combustion. The uncertainties associated with high-temperature combustion may affect at least three different accident scenarios: the in-cavity oxidation of combustible gases produced by core-concrete interactions, the direct containment heating hydrogen problem, and the possibility of local detonations. How these uncertainties may affect the sequence of various accident scenarios is discussed and recommendations are made to reduce these uncertainties. 40 references

  6. Uncertainty in hydrological signatures

    Science.gov (United States)

    McMillan, Hilary; Westerberg, Ida

    2015-04-01

    Information that summarises the hydrological behaviour or flow regime of a catchment is essential for comparing responses of different catchments to understand catchment organisation and similarity, and for many other modelling and water-management applications. Such information types derived as an index value from observed data are known as hydrological signatures, and can include descriptors of high flows (e.g. mean annual flood), low flows (e.g. mean annual low flow, recession shape), the flow variability, flow duration curve, and runoff ratio. Because the hydrological signatures are calculated from observed data such as rainfall and flow records, they are affected by uncertainty in those data. Subjective choices in the method used to calculate the signatures create a further source of uncertainty. Uncertainties in the signatures may affect our ability to compare different locations, to detect changes, or to compare future water resource management scenarios. The aim of this study was to contribute to the hydrological community's awareness and knowledge of data uncertainty in hydrological signatures, including typical sources, magnitude and methods for its assessment. We proposed a generally applicable method to calculate these uncertainties based on Monte Carlo sampling and demonstrated it for a variety of commonly used signatures. The study was made for two data rich catchments, the 50 km2 Mahurangi catchment in New Zealand and the 135 km2 Brue catchment in the UK. For rainfall data the uncertainty sources included point measurement uncertainty, the number of gauges used in calculation of the catchment spatial average, and uncertainties relating to lack of quality control. For flow data the uncertainty sources included uncertainties in stage/discharge measurement and in the approximation of the true stage-discharge relation by a rating curve. The resulting uncertainties were compared across the different signatures and catchments, to quantify uncertainty

  7. Capacity and Entry Deterrence under Demand Uncertainty

    DEFF Research Database (Denmark)

    Poddar, Sougata

    I consider a two period model with an incumbent firm and a potential entrant each of whom produces a homogeneous good. There is a demand uncertainty: it can be high or low and it realizes in the second period. The question I ask: How by choosing capacity at an earlier period of actual production...... of output and, more importently, not knowing which state of demand is going to realize, and knowing that there is a potential entrant, the incumbent firm can influence the outcome of the game by changing its initial condition. To that end, I study how the impact of the distribution of uncertainty deeply...

  8. The Return to Foreign Aid

    DEFF Research Database (Denmark)

    Dalgaard, Carl-Johan Lars; Hansen, Henrik

    2017-01-01

    We estimate the average rate of return on investments financed by aid and by domestic resource mobilisation, using aggregate data. Both returns are expected to vary across countries and time. Consequently we develop a correlated random coefficients model to estimate the average returns. Across...... different estimators and two different data sources for GDP and investment our findings are remarkably robust; the average gross return on ‘aid investments’ is about 20 per cent. This is in accord with micro estimates of the economic rate of return on aid projects and with aggregate estimates of the rate...

  9. The Equity Share in New Issues and Aggregate Stock Returns

    OpenAIRE

    Malcolm Baker; Jeffrey Wurgler

    1999-01-01

    The share of equity issues in total new equity and debt issues is a strong predictor of U.S. stock market returns between 1928 and 1997. In particular, firms issue relatively more equity than debt just before periods of low market returns. The equity share in new issues has stable predictive power in both halves of the sample period, and after controlling for other known predictors. We do not find support for efficient market ex

  10. Uncertainty in social dilemmas

    NARCIS (Netherlands)

    Kwaadsteniet, Erik Willem de

    2007-01-01

    This dissertation focuses on social dilemmas, and more specifically, on environmental uncertainty in these dilemmas. Real-life social dilemma situations are often characterized by uncertainty. For example, fishermen mostly do not know the exact size of the fish population (i.e., resource size

  11. Uncertainty and Climate Change

    OpenAIRE

    Berliner, L. Mark

    2003-01-01

    Anthropogenic, or human-induced, climate change is a critical issue in science and in the affairs of humankind. Though the target of substantial research, the conclusions of climate change studies remain subject to numerous uncertainties. This article presents a very brief review of the basic arguments regarding anthropogenic climate change with particular emphasis on uncertainty.

  12. Deterministic uncertainty analysis

    International Nuclear Information System (INIS)

    Worley, B.A.

    1987-01-01

    Uncertainties of computer results are of primary interest in applications such as high-level waste (HLW) repository performance assessment in which experimental validation is not possible or practical. This work presents an alternate deterministic approach for calculating uncertainties that has the potential to significantly reduce the number of computer runs required for conventional statistical analysis. 7 refs., 1 fig

  13. Uncertainty and simulation

    International Nuclear Information System (INIS)

    Depres, B.; Dossantos-Uzarralde, P.

    2009-01-01

    More than 150 researchers and engineers from universities and the industrial world met to discuss on the new methodologies developed around assessing uncertainty. About 20 papers were presented and the main topics were: methods to study the propagation of uncertainties, sensitivity analysis, nuclear data covariances or multi-parameter optimisation. This report gathers the contributions of CEA researchers and engineers

  14. Joint pricing and inventory replenishment decisions with returns and expediting

    NARCIS (Netherlands)

    Zhu, Stuart X.

    2012-01-01

    We study a single-item periodic-review model for the joint pricing and inventory replenishment problem with returns and expediting. Demand in consecutive periods are independent random variables and their distributions are price sensitive. At the end of each period, after the demand is realized, a

  15. Uncertainties of the 50-year wind from short time series using generalized extreme value distribution and generalized Pareto distribution

    DEFF Research Database (Denmark)

    Larsén, Xiaoli Guo; Mann, Jakob; Rathmann, Ole

    2015-01-01

    This study examines the various sources to the uncertainties in the application of two widely used extreme value distribution functions, the generalized extreme value distribution (GEVD) and the generalized Pareto distribution (GPD). The study is done through the analysis of measurements from...... as a guideline for applying GEVD and GPD to wind time series of limited length. The data analysis shows that, with reasonable choice of relevant parameters, GEVD and GPD give consistent estimates of the return winds. For GEVD, the base period should be chosen in accordance with the occurrence of the extreme wind...

  16. Conditional uncertainty principle

    Science.gov (United States)

    Gour, Gilad; Grudka, Andrzej; Horodecki, Michał; Kłobus, Waldemar; Łodyga, Justyna; Narasimhachar, Varun

    2018-04-01

    We develop a general operational framework that formalizes the concept of conditional uncertainty in a measure-independent fashion. Our formalism is built upon a mathematical relation which we call conditional majorization. We define conditional majorization and, for the case of classical memory, we provide its thorough characterization in terms of monotones, i.e., functions that preserve the partial order under conditional majorization. We demonstrate the application of this framework by deriving two types of memory-assisted uncertainty relations, (1) a monotone-based conditional uncertainty relation and (2) a universal measure-independent conditional uncertainty relation, both of which set a lower bound on the minimal uncertainty that Bob has about Alice's pair of incompatible measurements, conditioned on arbitrary measurement that Bob makes on his own system. We next compare the obtained relations with their existing entropic counterparts and find that they are at least independent.

  17. Physical Uncertainty Bounds (PUB)

    Energy Technology Data Exchange (ETDEWEB)

    Vaughan, Diane Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Preston, Dean L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-03-19

    This paper introduces and motivates the need for a new methodology for determining upper bounds on the uncertainties in simulations of engineered systems due to limited fidelity in the composite continuum-level physics models needed to simulate the systems. We show that traditional uncertainty quantification methods provide, at best, a lower bound on this uncertainty. We propose to obtain bounds on the simulation uncertainties by first determining bounds on the physical quantities or processes relevant to system performance. By bounding these physics processes, as opposed to carrying out statistical analyses of the parameter sets of specific physics models or simply switching out the available physics models, one can obtain upper bounds on the uncertainties in simulated quantities of interest.

  18. Measurement uncertainty and probability

    CERN Document Server

    Willink, Robin

    2013-01-01

    A measurement result is incomplete without a statement of its 'uncertainty' or 'margin of error'. But what does this statement actually tell us? By examining the practical meaning of probability, this book discusses what is meant by a '95 percent interval of measurement uncertainty', and how such an interval can be calculated. The book argues that the concept of an unknown 'target value' is essential if probability is to be used as a tool for evaluating measurement uncertainty. It uses statistical concepts, such as a conditional confidence interval, to present 'extended' classical methods for evaluating measurement uncertainty. The use of the Monte Carlo principle for the simulation of experiments is described. Useful for researchers and graduate students, the book also discusses other philosophies relating to the evaluation of measurement uncertainty. It employs clear notation and language to avoid the confusion that exists in this controversial field of science.

  19. Real exchange rate persistence and the excess return puzzle

    DEFF Research Database (Denmark)

    Juselius, Katarina; Assenmacher, Katrin

    2017-01-01

    The PPP puzzle refers to the wide swings of nominal exchange rates around their long-run equilibrium values whereas the excess return puzzle represents the persistent deviation of the domestic-foreign interest rate differential from the expected change in the nominal exchange rate. Using the I(2......) cointegrated VAR model, much of the excess return puzzle disappears when an uncertainty premium in the foreign exchange market, proxied by the persistent PPP gap, is introduced. Self-reinforcing feedback mechanisms seem to cause the persistence in the Swiss-US parity conditions. These results support imperfect...

  20. Uncertainty Propagation in OMFIT

    Science.gov (United States)

    Smith, Sterling; Meneghini, Orso; Sung, Choongki

    2017-10-01

    A rigorous comparison of power balance fluxes and turbulent model fluxes requires the propagation of uncertainties in the kinetic profiles and their derivatives. Making extensive use of the python uncertainties package, the OMFIT framework has been used to propagate covariant uncertainties to provide an uncertainty in the power balance calculation from the ONETWO code, as well as through the turbulent fluxes calculated by the TGLF code. The covariant uncertainties arise from fitting 1D (constant on flux surface) density and temperature profiles and associated random errors with parameterized functions such as a modified tanh. The power balance and model fluxes can then be compared with quantification of the uncertainties. No effort is made at propagating systematic errors. A case study will be shown for the effects of resonant magnetic perturbations on the kinetic profiles and fluxes at the top of the pedestal. A separate attempt at modeling the random errors with Monte Carlo sampling will be compared to the method of propagating the fitting function parameter covariant uncertainties. Work supported by US DOE under DE-FC02-04ER54698, DE-FG2-95ER-54309, DE-SC 0012656.

  1. The role of regulatory uncertainty in certificate markets: A case study of the Swedish/Norwegian market

    International Nuclear Information System (INIS)

    Fagiani, Riccardo; Hakvoort, Rudi

    2014-01-01

    Price volatility in green certificate markets reflects uncertainty over future prices, representing a major source of risk for renewable energy generators. Price risk is considered the principal deficiency of this market-based policy since it causes investors to require higher returns. Moreover, investors are exposed to regulatory risk; namely, the risk that a change in the regulation will materially impact the certificate price. Regulatory uncertainty is reflected in market volatility exacerbating certificate price risk. Using an econometric approach, we investigate the role of regulatory changes on price volatility in the Swedish certificate market. The results of our analysis indicate that regulatory changes strongly affect certificate markets, resulting in periods of higher volatility. Moreover, we analyze whether certificate price volatility has changed after creating a joint Swedish/Norwegian market. Results indicate that the ambivalence surrounding the creation of this bigger market led to a period of increased price volatility between 2010 and 2011. Overall, this article brings a better understanding of the role of regulatory uncertainty on certificate markets, and gives evidence for its negative impact in terms of increased price volatility. - Highlights: • Paper analyzes the impact of regulatory changes on certificate price volatility. • Regulatory changes affect market volatility and price risk. • Regulatory uncertainty harms certificate markets. • The bigger Swedish/Norwegian market has not resulted in lower volatility yet

  2. Return to the... past

    International Nuclear Information System (INIS)

    Ammerich, M.

    2009-01-01

    This article goes back over the incidents occurring during the summer 2008, that is to say the uranium release from the Socatri facility in the South of France. From this point, the purpose studies the radiological situation of the Camargue seashore; the levels of radioactivity are from 3 to thirty times higher than these ones expected in this area, but the natural radioactivity with thorium and uranium coming from the granitic massifs erosion brings an important part. It is difficult to make the part between human and natural contribution to ambient radioactivity. However, it appears that to limit the water consumption until the time of dilution played its part was absolutely necessary. Then, because it is question of water, the drinking water is tackled. Some mineral waters go over the recommended limits of doses. A last return to the past with the radioactive watches, but this time with actual watches that activate detection. Two watches contained promethium 147, 147 Pm is a beta emitter but also gamma emitter. To end, in Ireland and Great Britain, some fire detectors contain americium 241. In fact, this article constitutes a summary of different abnormalities around radioactivity. (N.C.)

  3. The return of religion

    Directory of Open Access Journals (Sweden)

    S. Griffioen

    2011-06-01

    Full Text Available Religion is back in Philosophy as a respectable subject. Part 1 first charts what MacIntyre, Taylor and Derrida have meant in this regard. Subsequently, it turns to the Enlightenment to determine what constituted the breakthrough. It is found that even where the Enlightenment gave maximum room to religion i.e. as a civic religion and as “religion of the heart” it still excluded a constitutive relation to a transcendent revelation. Part 2 centres on the religion-faith distinction in reformational philosophy. Similar to the Enlightenment, religion is understood as part of human nature. However, human nature itself is conceived as intrinsically religious and depending for its light on revelation. Secondly, “religion” in this context also encompasses idols and religious substitutes. Thus, it directs attention to shopping malls, football stadiums, health policy, et cetera, as possible contexts of a return of religion. Examples show that this has become a popular approach. However, most of the publications surveyed fail to distinguish between an “analogical” and a “pistically qualified” use of religion, and are open to exaggerations (the shopping mall and football stadiums as temples, etc.. At this junction, the relevance is shown of the religion-faith distinction as well as of Elaine Botha’s theory of metaphors. The epilogue offers an integration of parts one and two.

  4. Verification of uncertainty budgets

    DEFF Research Database (Denmark)

    Heydorn, Kaj; Madsen, B.S.

    2005-01-01

    , and therefore it is essential that the applicability of the overall uncertainty budget to actual measurement results be verified on the basis of current experimental data. This should be carried out by replicate analysis of samples taken in accordance with the definition of the measurand, but representing...... the full range of matrices and concentrations for which the budget is assumed to be valid. In this way the assumptions made in the uncertainty budget can be experimentally verified, both as regards sources of variability that are assumed negligible, and dominant uncertainty components. Agreement between...

  5. PUC fast track nips returns

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    In the first of what it says will be annual cost-of-capital proceedings to set returns on equity and rates of return on rate base for electric utilities, the California Public Utilities Commission (PUC) lowered from 1989 levels the 1990 returns on common equity (ROE) and rates of return (ROR) for the state's four major investor-owned electric utilities. Under this fast-track procedure, by May 8 of every year, utilities will have to file an application for rate adjustments that reflect their projected costs of capital for the following year

  6. The return to foreign aid

    DEFF Research Database (Denmark)

    Dalgaard, Carl-Johan Lars; Hansen, Henrik

    We investigate the marginal productivity of investment across countries. The aim is to estimate the return on investments financed by foreign aid and by domestic resource mobilization, using aggregate data. Both returns are expected to vary across countries and time. Consequently we develop...... a correlated random coefficients model, to estimate the average aggregate return on ‘aid investments’ and ‘domestic investments’. Across different estimators and two different sources for GDP and investment data our findings are remarkably robust; the average gross return on ‘aid investments’ is about 20 per...

  7. Returns to schooling in the Portuguese economy: a reassessment

    Directory of Open Access Journals (Sweden)

    Maria Manuel Campos

    2018-06-01

    Full Text Available This paper provides an overview of the evolution of private returns to schooling in the Portuguese economy along the 1986-2013 period. We estimate the returns separately for men and women, at the mean and along the conditional wage distribution. Returns to schooling are found to be high, particularly for women, and to increase along the distribution. The magnitude of the returns increased throughout the 1986-2013 period, but particularly in the 1990s. We also provide estimates of the relative wage premium associated with specific levels of educational attainment and find that they are highest for tertiary education. In the first decades under analysis, relative wage premia associated with the 9th grade stand above those estimated for secondary education, whereas in the most recent period these differences are negligible.

  8. Value at Risk and Hedge Fund Return - Does High Risk Bring High Return?

    OpenAIRE

    Jing, Tao; Zhao, Hongxiang

    2010-01-01

    This paper mainly focuses on the correlation between live hedge fund return and their value at risk (VaR), and is based on the historical data from May 2000 to April 2010. The authors adopt portfolio level analyses and fund level cross-sectional regression, and find that there is significant positive correlation, both statistically and economically, between the hedge fund return and VaRs (parametric, non-parametric and GARCH). Further research is conducted by sub-dividing the overall period i...

  9. Return Migration to Mexico: Does Health Matter?

    Science.gov (United States)

    Arenas, Erika; Goldman, Noreen; Pebley, Anne R; Teruel, Graciela

    2015-12-01

    We use data from three rounds of the Mexican Family Life Survey to examine whether migrants in the United States returning to Mexico in the period 2005-2012 have worse health than those remaining in the United States. Despite extensive interest by demographers in health-related selection, this has been a neglected area of study in the literature on U.S.-Mexico migration, and the few results to date have been contradictory and inconclusive. Using five self-reported health variables collected while migrants resided in the United States and subsequent migration history, we find direct evidence of higher probabilities of return migration for Mexican migrants in poor health as well as lower probabilities of return for migrants with improving health. These findings are robust to the inclusion of potential confounders reflecting the migrants' demographic characteristics, economic situation, family ties, and origin and destination characteristics. We anticipate that in the coming decade, health may become an even more salient issue in migrants' decisions about returning to Mexico, given the recent expansion in access to health insurance in Mexico.

  10. Evaluating prediction uncertainty

    International Nuclear Information System (INIS)

    McKay, M.D.

    1995-03-01

    The probability distribution of a model prediction is presented as a proper basis for evaluating the uncertainty in a model prediction that arises from uncertainty in input values. Determination of important model inputs and subsets of inputs is made through comparison of the prediction distribution with conditional prediction probability distributions. Replicated Latin hypercube sampling and variance ratios are used in estimation of the distributions and in construction of importance indicators. The assumption of a linear relation between model output and inputs is not necessary for the indicators to be effective. A sequential methodology which includes an independent validation step is applied in two analysis applications to select subsets of input variables which are the dominant causes of uncertainty in the model predictions. Comparison with results from methods which assume linearity shows how those methods may fail. Finally, suggestions for treating structural uncertainty for submodels are presented

  11. Returns on Investment in California County Departments of Public Health.

    Science.gov (United States)

    Brown, Timothy T

    2016-08-01

    To estimate the average return on investment for the overall activities of county departments of public health in California. I gathered the elements necessary to estimate the average return on investment for county departments of public health in California during the period 2001 to 2008-2009. These came from peer-reviewed journal articles published as part of a larger project to develop a method for determining return on investment for public health by using a health economics framework. I combined these elements by using the standard formula for computing return on investment, and performed a sensitivity analysis. Then I compared the return on investment for county departments of public health with the returns on investment generated for various aspects of medical care. The estimated return on investment from $1 invested in county departments of public health in California ranges from $67.07 to $88.21. The very large estimated return on investment for California county departments of public health relative to the return on investment for selected aspects of medical care suggests that public health is a wise investment.

  12. Returns on Investment in California County Departments of Public Health

    Science.gov (United States)

    2016-01-01

    Objectives. To estimate the average return on investment for the overall activities of county departments of public health in California. Methods. I gathered the elements necessary to estimate the average return on investment for county departments of public health in California during the period 2001 to 2008–2009. These came from peer-reviewed journal articles published as part of a larger project to develop a method for determining return on investment for public health by using a health economics framework. I combined these elements by using the standard formula for computing return on investment, and performed a sensitivity analysis. Then I compared the return on investment for county departments of public health with the returns on investment generated for various aspects of medical care. Results. The estimated return on investment from $1 invested in county departments of public health in California ranges from $67.07 to $88.21. Conclusions. The very large estimated return on investment for California county departments of public health relative to the return on investment for selected aspects of medical care suggests that public health is a wise investment. PMID:27310339

  13. A erosividade das chuvas em Fortaleza (CE: I - distribuição, probabilidade de ocorrência e período de retorno - 1ª aproximação Rainfall erosivity in Fortaleza, Ceará State, Brazil: I - distribution, probability of occurrence and return period - 1st approximation

    Directory of Open Access Journals (Sweden)

    A. S. Dias

    2003-04-01

    Loss Equation to predict erosion losses and for conservation planning requires an evaluation of index values of local rainfall erosivity. As a contribution to knowledge on these indexes in the coastal zone of Ceará State, the objectives of this study were: (a to determine the R factor and the annual EI30 index values, its monthly distribution, probability of occurrence and return periods in Fortaleza, Ceará State, Brazil for the period of 1962 to 1981, and (b to create a data bank that allows, by a subsequent analysis, the assessment of correlation between the EI30 index and monthly rainfall amounts in order to simplify the index calculation and to update its values for the years 1982 to 2000. Total rainfall kinetic energy, uniform intensities, maximum 30 minutes intensity and the EI30 index for individual rainstorms were determined on 7,300 daily rain gauge charts from 1962 to 1981, available at the Meteorological Station of the Federal University of Ceará, in Fortaleza. The distribution frequency for the maximum individual and annual EI30 values and their return periods were calculated and plotted on curves of occurrence probability of these values. Over the 20 years period, the R factor found in Fortaleza was 6,774 in a range from 2,237 to 12,881 MJ mm (ha h y-1 and this average annual value is expected to occur, or to be exceeded, at least once in 2.2 years with an occurrence probability of 46 %. Maximum individual EI30 values estimated for return periods of 2, 5, 20, 50 and 100 years were 1,363, 2,415, 3,783, 5,950 and 8,000 MJ mm (ha h-1, respectively. Distribution of the local erosivity showed that 97 % of the annual EI30 occurs in the first semester of the year. Highest soil and water losses are to be expected during the months of February to May, since 70 % of the annual erosivity index value occurs in this quarter of the year, when conventional tillage is used for seedbed preparation and the canopy is incipient.

  14. Uncertainties and climatic change

    International Nuclear Information System (INIS)

    De Gier, A.M.; Opschoor, J.B.; Van de Donk, W.B.H.J.; Hooimeijer, P.; Jepma, J.; Lelieveld, J.; Oerlemans, J.; Petersen, A.

    2008-01-01

    Which processes in the climate system are misunderstood? How are scientists dealing with uncertainty about climate change? What will be done with the conclusions of the recently published synthesis report of the IPCC? These and other questions were answered during the meeting 'Uncertainties and climate change' that was held on Monday 26 November 2007 at the KNAW in Amsterdam. This report is a compilation of all the presentations and provides some conclusions resulting from the discussions during this meeting. [mk] [nl

  15. Mechanics and uncertainty

    CERN Document Server

    Lemaire, Maurice

    2014-01-01

    Science is a quest for certainty, but lack of certainty is the driving force behind all of its endeavors. This book, specifically, examines the uncertainty of technological and industrial science. Uncertainty and Mechanics studies the concepts of mechanical design in an uncertain setting and explains engineering techniques for inventing cost-effective products. Though it references practical applications, this is a book about ideas and potential advances in mechanical science.

  16. Uncertainty: lotteries and risk

    OpenAIRE

    Ávalos, Eloy

    2011-01-01

    In this paper we develop the theory of uncertainty in a context where the risks assumed by the individual are measurable and manageable. We primarily use the definition of lottery to formulate the axioms of the individual's preferences, and its representation through the utility function von Neumann - Morgenstern. We study the expected utility theorem and its properties, the paradoxes of choice under uncertainty and finally the measures of risk aversion with monetary lotteries.

  17. Uncertainty calculations made easier

    International Nuclear Information System (INIS)

    Hogenbirk, A.

    1994-07-01

    The results are presented of a neutron cross section sensitivity/uncertainty analysis performed in a complicated 2D model of the NET shielding blanket design inside the ITER torus design, surrounded by the cryostat/biological shield as planned for ITER. The calculations were performed with a code system developed at ECN Petten, with which sensitivity/uncertainty calculations become relatively simple. In order to check the deterministic neutron transport calculations (performed with DORT), calculations were also performed with the Monte Carlo code MCNP. Care was taken to model the 2.0 cm wide gaps between two blanket segments, as the neutron flux behind the vacuum vessel is largely determined by neutrons streaming through these gaps. The resulting neutron flux spectra are in excellent agreement up to the end of the cryostat. It is noted, that at this position the attenuation of the neutron flux is about 1 l orders of magnitude. The uncertainty in the energy integrated flux at the beginning of the vacuum vessel and at the beginning of the cryostat was determined in the calculations. The uncertainty appears to be strongly dependent on the exact geometry: if the gaps are filled with stainless steel, the neutron spectrum changes strongly, which results in an uncertainty of 70% in the energy integrated flux at the beginning of the cryostat in the no-gap-geometry, compared to an uncertainty of only 5% in the gap-geometry. Therefore, it is essential to take into account the exact geometry in sensitivity/uncertainty calculations. Furthermore, this study shows that an improvement of the covariance data is urgently needed in order to obtain reliable estimates of the uncertainties in response parameters in neutron transport calculations. (orig./GL)

  18. Managing uncertainty during r&d projects: a case study

    NARCIS (Netherlands)

    Wouters, Marc; Roorda, Berend; Gal, Ruud

    2011-01-01

    Firms make signifi cant investments in R&D projects, yet the economic return is often diffi cult to predict because of signifi cant technological and commercial uncertainty. We present an innovative and practical method for managing R&D projects, and we discuss its application to a large R&D

  19. Corporate Governance and Equity Returns

    OpenAIRE

    Uchida, Shigeru

    2012-01-01

    This paper analyses the relationship between corporate governance and equity returns from the small investors view point. A primary survey has been conducted to gather the data required to examine the link. Preliminary result of the study shows that the four elements of governance: board structure, transparency, fairness and responsibility are positively related with equity returns.

  20. On return rate implied by behavioural present value

    OpenAIRE

    Piasecki, Krzysztof

    2013-01-01

    The future value of a security is described as a random variable. Distribution of this random variable is the formal image of risk uncertainty. On the other side, any present value is defined as a value equivalent to the given future value. This equivalence relationship is a subjective. Thus follows, that present value is described as a fuzzy number, which is depend on the investor's susceptibility to behavioural factors. All above reasons imply, that return rate is given as a fuzzy probabili...

  1. Uncertainty of Hydrological Drought Characteristics with Copula Functions and Probability Distributions: A Case Study of Weihe River, China

    Directory of Open Access Journals (Sweden)

    Panpan Zhao

    2017-05-01

    Full Text Available This study investigates the sensitivity and uncertainty of hydrological droughts frequencies and severity in the Weihe Basin, China during 1960–2012, by using six commonly used univariate probability distributions and three Archimedean copulas to fit the marginal and joint distributions of drought characteristics. The Anderson-Darling method is used for testing the goodness-of-fit of the univariate model, and the Akaike information criterion (AIC is applied to select the best distribution and copula functions. The results demonstrate that there is a very strong correlation between drought duration and drought severity in three stations. The drought return period varies depending on the selected marginal distributions and copula functions and, with an increase of the return period, the differences become larger. In addition, the estimated return periods (both co-occurrence and joint from the best-fitted copulas are the closet to those from empirical distribution. Therefore, it is critical to select the appropriate marginal distribution and copula function to model the hydrological drought frequency and severity. The results of this study can not only help drought investigation to select a suitable probability distribution and copulas function, but are also useful for regional water resource management. However, a few limitations remain in this study, such as the assumption of stationary of runoff series.

  2. Justification for recommended uncertainties

    International Nuclear Information System (INIS)

    Pronyaev, V.G.; Badikov, S.A.; Carlson, A.D.

    2007-01-01

    The uncertainties obtained in an earlier standards evaluation were considered to be unrealistically low by experts of the US Cross Section Evaluation Working Group (CSEWG). Therefore, the CSEWG Standards Subcommittee replaced the covariance matrices of evaluated uncertainties by expanded percentage errors that were assigned to the data over wide energy groups. There are a number of reasons that might lead to low uncertainties of the evaluated data: Underestimation of the correlations existing between the results of different measurements; The presence of unrecognized systematic uncertainties in the experimental data can lead to biases in the evaluated data as well as to underestimations of the resulting uncertainties; Uncertainties for correlated data cannot only be characterized by percentage uncertainties or variances. Covariances between evaluated value at 0.2 MeV and other points obtained in model (RAC R matrix and PADE2 analytical expansion) and non-model (GMA) fits of the 6 Li(n,t) TEST1 data and the correlation coefficients are presented and covariances between the evaluated value at 0.045 MeV and other points (along the line or column of the matrix) as obtained in EDA and RAC R matrix fits of the data available for reactions that pass through the formation of the 7 Li system are discussed. The GMA fit with the GMA database is shown for comparison. The following diagrams are discussed: Percentage uncertainties of the evaluated cross section for the 6 Li(n,t) reaction and the for the 235 U(n,f) reaction; estimation given by CSEWG experts; GMA result with full GMA database, including experimental data for the 6 Li(n,t), 6 Li(n,n) and 6 Li(n,total) reactions; uncertainties in the GMA combined fit for the standards; EDA and RAC R matrix results, respectively. Uncertainties of absolute and 252 Cf fission spectrum averaged cross section measurements, and deviations between measured and evaluated values for 235 U(n,f) cross-sections in the neutron energy range 1

  3. Factor Structure in Commodity Futures Return and Volatility

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Lunde, Asger; Olesen, Kasper Vinther

    Using data on more than 750 million futures trades during 2004-2013, we analyze eight stylized facts of commodity price and volatility dynamics in the post financialization period. We pay particular attention to the factor structure in returns and volatility and to commodity market integration...... with the equity market. We find evidence of a factor structure in daily commodity futures returns. However, the factor structure in daily commodity futures volatility is even stronger than in returns. When computing model-free realized commodity betas with the stock market we find that they were high during 2008......-2010 but have since returned to the pre-crisis level close to zero. The common factor in commodity volatility is nevertheless clearly related to stock market volatility. We conclude that, while commodity markets appear to again be segmented from the equity market when only returns are considered, commodity...

  4. Probabilistic numerics and uncertainty in computations.

    Science.gov (United States)

    Hennig, Philipp; Osborne, Michael A; Girolami, Mark

    2015-07-08

    We deliver a call to arms for probabilistic numerical methods : algorithms for numerical tasks, including linear algebra, integration, optimization and solving differential equations, that return uncertainties in their calculations. Such uncertainties, arising from the loss of precision induced by numerical calculation with limited time or hardware, are important for much contemporary science and industry. Within applications such as climate science and astrophysics, the need to make decisions on the basis of computations with large and complex data have led to a renewed focus on the management of numerical uncertainty. We describe how several seminal classic numerical methods can be interpreted naturally as probabilistic inference. We then show that the probabilistic view suggests new algorithms that can flexibly be adapted to suit application specifics, while delivering improved empirical performance. We provide concrete illustrations of the benefits of probabilistic numeric algorithms on real scientific problems from astrometry and astronomical imaging, while highlighting open problems with these new algorithms. Finally, we describe how probabilistic numerical methods provide a coherent framework for identifying the uncertainty in calculations performed with a combination of numerical algorithms (e.g. both numerical optimizers and differential equation solvers), potentially allowing the diagnosis (and control) of error sources in computations.

  5. The effect of Malaysia general election on stock market returns.

    Science.gov (United States)

    Liew, Venus Khim-Sen; Rowland, Racquel

    2016-01-01

    During the latest episode of general election held in Malaysia, it is observed that the FBMKLCI index was lifted 62.52 points in a day soon after the announcement of election outcome. Moreover, the index registered a highest gain of 96.29 points in the middle of the intra-day trade. This suggests that investors who had got the right direction could make profitable intra-day trading the next trading day of the general election date. Results from statistical analysis uncover significant before-election-effect and after-election-effect from the most recent general elections held in Malaysia. Different subsets of macroeconomic variables are found to have significant role on stock market return depending on the market situation. Remarkably, when there was close fight between the two major political parties during the 2008 and 2013 election years, political uncertainty showed up its negative and significant role in influencing the stock market return. The major implication of these findings is that while investors may seek abnormal returns before and after the next general election, which is around the corner, they will have to pay attention on the influence of macroeconomic variables and political uncertainty on stock market return during the election year.

  6. Credibilistic multi-period portfolio optimization based on scenario tree

    Science.gov (United States)

    Mohebbi, Negin; Najafi, Amir Abbas

    2018-02-01

    In this paper, we consider a multi-period fuzzy portfolio optimization model with considering transaction costs and the possibility of risk-free investment. We formulate a bi-objective mean-VaR portfolio selection model based on the integration of fuzzy credibility theory and scenario tree in order to dealing with the markets uncertainty. The scenario tree is also a proper method for modeling multi-period portfolio problems since the length and continuity of their horizon. We take the return and risk as well cardinality, threshold, class, and liquidity constraints into consideration for further compliance of the model with reality. Then, an interactive dynamic programming method, which is based on a two-phase fuzzy interactive approach, is employed to solve the proposed model. In order to verify the proposed model, we present an empirical application in NYSE under different circumstances. The results show that the consideration of data uncertainty and other real-world assumptions lead to more practical and efficient solutions.

  7. The Individual Economic Returns to Volunteering in Work Life

    DEFF Research Database (Denmark)

    Qvist, Hans-Peter; Munk, Martin David

    2018-01-01

    This article examines the individual economic returns to volunteering during different stages of working life. The article uses a unique panel dataset created by combining rich survey data from Denmark with information on wages from administrative registers covering the period from 2004 to 2012....... Applying a two-way fixed effects regression model that controls for both period-specific and individual-specific effects, the article finds that for labour market entrants and for people in the early stages of their working life, an additional year of volunteer work experience yields a significant positive...... return. However, the economic returns to volunteer work experience decrease as a function of professional labour market experience. For people with more than six years of professional labour market experience, the economic returns to volunteer work experience are insignificant. On these grounds...

  8. Dealing with exploration uncertainties

    International Nuclear Information System (INIS)

    Capen, E.

    1992-01-01

    Exploration for oil and gas should fulfill the most adventurous in their quest for excitement and surprise. This paper tries to cover that tall order. The authors will touch on the magnitude of the uncertainty (which is far greater than in most other businesses), the effects of not knowing target sizes very well, how to build uncertainty into analyses naturally, how to tie reserves and chance estimates to economics, and how to look at the portfolio effect of an exploration program. With no apologies, the authors will be using a different language for some readers - the language of uncertainty, which means probability and statistics. These tools allow one to combine largely subjective exploration information with the more analytical data from the engineering and economic side

  9. Fundamental uncertainty and stock market volatility

    NARCIS (Netherlands)

    Arnold, I.J.M.; Vrugt, E.B.

    2008-01-01

    We provide empirical evidence on the link between stock market volatility and macroeconomic uncertainty. We show that US stock market volatility is significantly related to the dispersion in economic forecasts from participants in the Survey of Professional Forecasters over the period 1969 to 1996.

  10. Strategic Capital Budgeting : Asset Replacement Under Uncertainty

    NARCIS (Netherlands)

    Pawlina, G.; Kort, P.M.

    2001-01-01

    We consider a firm's decision to replace an existing production technology with a new, more cost-efficient one.Kulatilaka and Perotti [1998, Management Science] nd that, in a two-period model, increased product market uncertainty could encourage the firm to invest strategically in the new

  11. Financial development, uncertainty and economic growth

    NARCIS (Netherlands)

    Lensink, B.W.

    By performing a cross-country growth regression for the 1970-1998 period this paper finds evidence for the fact that the impact of policy uncertainty on economic growth depends on the development of the financial sector. It appears that a higher level of financial development partly mitigates the

  12. Stock market volatility and macroeconomic uncertainty

    NARCIS (Netherlands)

    Arnold, I.J.M.; Vrugt, E.B.

    2006-01-01

    This paper provides empirical evidence on the link between stock market volatility and macroeconomic uncertainty. We show that US stock market volatility is significantly related to the dispersion in economic forecasts from SPF survey participants over the period from 1969 to 1996. This link is much

  13. The Impact of Capital Structure on Stock Returns: International Evidence

    Directory of Open Access Journals (Sweden)

    Reza TAHMOORESPOUR

    2015-03-01

    Full Text Available This study examines the relationship between capital structure and stock returns of firms in the following eight countries in the Asia Pacific regionfor a period of 22 years from 1990 to 2012. The methodology is Panel Regression. The results indicate that the effect of capital structure depends on the nature of industry as well as market. In Australia, China, and Korea, return of companies in the Basic Material industry have negative relationship with debt to common equity. Long term debt to common equity positively affects the return of firms in Australia and Korea in the Basic Material industry.

  14. Investment Returns and Economic Fundamentals in International Art Markets

    OpenAIRE

    Renneboog, L.D.R.; Spaenjers, C.

    2014-01-01

    Abstract: Works of art are neither easily tradable across borders, nor evaluated according to globally identical standards. We examine geographical segmentation and its effects on price formation and returns in the international art auction market. We find (i) a close connection between the country of sale and the type (e.g., nationality) of artworks sold; (ii) substantial international variation in average returns to art investments over the period 1971-2007; (iii) an impact of both global a...

  15. Uncertainty in artificial intelligence

    CERN Document Server

    Levitt, TS; Lemmer, JF; Shachter, RD

    1990-01-01

    Clearly illustrated in this volume is the current relationship between Uncertainty and AI.It has been said that research in AI revolves around five basic questions asked relative to some particular domain: What knowledge is required? How can this knowledge be acquired? How can it be represented in a system? How should this knowledge be manipulated in order to provide intelligent behavior? How can the behavior be explained? In this volume, all of these questions are addressed. From the perspective of the relationship of uncertainty to the basic questions of AI, the book divides naturally i

  16. Sensitivity and uncertainty analysis

    CERN Document Server

    Cacuci, Dan G; Navon, Ionel Michael

    2005-01-01

    As computer-assisted modeling and analysis of physical processes have continued to grow and diversify, sensitivity and uncertainty analyses have become indispensable scientific tools. Sensitivity and Uncertainty Analysis. Volume I: Theory focused on the mathematical underpinnings of two important methods for such analyses: the Adjoint Sensitivity Analysis Procedure and the Global Adjoint Sensitivity Analysis Procedure. This volume concentrates on the practical aspects of performing these analyses for large-scale systems. The applications addressed include two-phase flow problems, a radiative c

  17. Assessment of volcanic hazards, vulnerability, risk and uncertainty (Invited)

    Science.gov (United States)

    Sparks, R. S.

    2009-12-01

    A volcanic hazard is any phenomenon that threatens communities . These hazards include volcanic events like pyroclastic flows, explosions, ash fall and lavas, and secondary effects such as lahars and landslides. Volcanic hazards are described by the physical characteristics of the phenomena, by the assessment of the areas that they are likely to affect and by the magnitude-dependent return period of events. Volcanic hazard maps are generated by mapping past volcanic events and by modelling the hazardous processes. Both these methods have their strengths and limitations and a robust map should use both approaches in combination. Past records, studied through stratigraphy, the distribution of deposits and age dating, are typically incomplete and may be biased. Very significant volcanic hazards, such as surge clouds and volcanic blasts, are not well-preserved in the geological record for example. Models of volcanic processes are very useful to help identify hazardous areas that do not have any geological evidence. They are, however, limited by simplifications and incomplete understanding of the physics. Many practical volcanic hazards mapping tools are also very empirical. Hazards maps are typically abstracted into hazards zones maps, which are some times called threat or risk maps. Their aim is to identify areas at high levels of threat and the boundaries between zones may take account of other factors such as roads, escape routes during evacuation, infrastructure. These boundaries may change with time due to new knowledge on the hazards or changes in volcanic activity levels. Alternatively they may remain static but implications of the zones may change as volcanic activity changes. Zone maps are used for planning purposes and for management of volcanic crises. Volcanic hazards maps are depictions of the likelihood of future volcanic phenomena affecting places and people. Volcanic phenomena are naturally variable, often complex and not fully understood. There are

  18. Uncertainty Analyses and Strategy

    International Nuclear Information System (INIS)

    Kevin Coppersmith

    2001-01-01

    The DOE identified a variety of uncertainties, arising from different sources, during its assessment of the performance of a potential geologic repository at the Yucca Mountain site. In general, the number and detail of process models developed for the Yucca Mountain site, and the complex coupling among those models, make the direct incorporation of all uncertainties difficult. The DOE has addressed these issues in a number of ways using an approach to uncertainties that is focused on producing a defensible evaluation of the performance of a potential repository. The treatment of uncertainties oriented toward defensible assessments has led to analyses and models with so-called ''conservative'' assumptions and parameter bounds, where conservative implies lower performance than might be demonstrated with a more realistic representation. The varying maturity of the analyses and models, and uneven level of data availability, result in total system level analyses with a mix of realistic and conservative estimates (for both probabilistic representations and single values). That is, some inputs have realistically represented uncertainties, and others are conservatively estimated or bounded. However, this approach is consistent with the ''reasonable assurance'' approach to compliance demonstration, which was called for in the U.S. Nuclear Regulatory Commission's (NRC) proposed 10 CFR Part 63 regulation (64 FR 8640 [DIRS 101680]). A risk analysis that includes conservatism in the inputs will result in conservative risk estimates. Therefore, the approach taken for the Total System Performance Assessment for the Site Recommendation (TSPA-SR) provides a reasonable representation of processes and conservatism for purposes of site recommendation. However, mixing unknown degrees of conservatism in models and parameter representations reduces the transparency of the analysis and makes the development of coherent and consistent probability statements about projected repository

  19. Bereaved Employee: Returning to Work

    Science.gov (United States)

    ... Work Working Through Grief About Us The Bereaved Employee: Returning to Work By Helen Fitzgerald, CT After ... One employer called a grief therapist to help employees after a co-worker reported the death of ...

  20. Total anomalous pulmonary venous return

    Science.gov (United States)

    ... pulmonary venous return, x-ray References Fraser CD, Kane LC. Congenital heart disease. In: Townsend CM Jr, ... 62. Review Date 10/17/2017 Updated by: Michael A. Chen, MD, PhD, Associate Professor of Medicine, ...

  1. Time-Varying Periodicity in Intraday Volatility

    DEFF Research Database (Denmark)

    Andersen, Torben Gustav; Thyrsgaard, Martin; Todorov, Viktor

    We develop a nonparametric test for deciding whether return volatility exhibits time-varying intraday periodicity using a long time-series of high-frequency data. Our null hypothesis, commonly adopted in work on volatility modeling, is that volatility follows a stationary process combined...... with a constant time-of-day periodic component. We first construct time-of-day volatility estimates and studentize the high-frequency returns with these periodic components. If the intraday volatility periodicity is invariant over time, then the distribution of the studentized returns should be identical across...... with estimating volatility moments through their sample counterparts. Critical values are computed via easy-to-implement simulation. In an empirical application to S&P 500 index returns, we find strong evidence for variation in the intraday volatility pattern driven in part by the current level of volatility...

  2. Problem Periods

    Science.gov (United States)

    ... ovary syndrome. Read our information on PCOS for teens , and see your doctor if you think you may have PCOS. Major weight loss. Girls who have anorexia will often stop having periods. When to see ...

  3. Return Migration and Working Choices

    OpenAIRE

    TANI, Massimiliano; MAHUTEAU, Stéphane

    2008-01-01

    Collective Action to Support the Reintegration of Return Migrants in their Country of Origin (MIREM) This paper uses the recent survey carried out in the framework of the MIREM project on returnees to Algeria, Morocco and Tunisia and studies the duration of emigration and the labour force status upon returning. The results suggest that age and the year of emigration play a central role in the migration decision, but they do not support the hypothesis that the duration of migration is deter...

  4. Capital Structure and Stock Returns

    OpenAIRE

    Ivo Welch

    2002-01-01

    U.S. corporations do not issue and repurchase debt and equity to counteract the mechanistic effects of stock returns on their debt-equity ratios. Thus over one- to five-year horizons, stock returns can explain about 40 percent of debt ratio dynamics. Although corporate net issuing activity is lively and although it can explain 60 percent of debt ratio dynamics (long-term debt issuing activity being most capital structurerelevant), corporate issuing motives remain largely a mystery. When stock...

  5. [Organising a successful return home].

    Science.gov (United States)

    Mézière, Anthony

    Discharge from hospital is a major component of the quality and efficiency of the healthcare system. The failures of the return home of elderly people testify to the difficulties of applying guidelines in the area of hospital discharge. The action plan decided in the hospital for a successful return home can be jeopardised for personal, relational, functional and structural reasons originating from the different players involved in the hospital discharge. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  6. Return Migration as Failure or Success?: The Determinants of Return Migration Intentions Among Moroccan Migrants in Europe.

    Science.gov (United States)

    de Haas, Hein; Fokkema, Tineke; Fihri, Mohamed Fassi

    Different migration theories generate competing hypotheses with regard to determinants of return migration. While neoclassical migration theory associates migration to the failure to integrate at the destination, the new economics of labour migration sees return migration as the logical stage after migrants have earned sufficient assets and knowledge and to invest in their origin countries. The projected return is then likely to be postponed for sustained or indefinite periods if integration is unsuccessful. So, from an indication or result of integration failure return is rather seen as a measure of success. Drawing on recent survey data ( N  = 2,832), this article tests these hypotheses by examining the main determinants of return intention among Moroccan migrants across Europe. The results indicate that structural integration through labour market participation, education and the maintenance of economic and social ties with receiving countries do not significantly affect return intentions. At the same time, investments and social ties to Morocco are positively related, and socio-cultural integration in receiving countries is negatively related to return migration intentions. The mixed results corroborate the idea that there is no uniform process of (return) migration and that competing theories might therefore be partly complementary.

  7. Risk-based flood protection planning under climate change and modeling uncertainty: a pre-alpine case study

    Science.gov (United States)

    Dittes, Beatrice; Kaiser, Maria; Špačková, Olga; Rieger, Wolfgang; Disse, Markus; Straub, Daniel

    2018-05-01

    Planning authorities are faced with a range of questions when planning flood protection measures: is the existing protection adequate for current and future demands or should it be extended? How will flood patterns change in the future? How should the uncertainty pertaining to this influence the planning decision, e.g., for delaying planning or including a safety margin? Is it sufficient to follow a protection criterion (e.g., to protect from the 100-year flood) or should the planning be conducted in a risk-based way? How important is it for flood protection planning to accurately estimate flood frequency (changes), costs and damage? These are questions that we address for a medium-sized pre-alpine catchment in southern Germany, using a sequential Bayesian decision making framework that quantitatively addresses the full spectrum of uncertainty. We evaluate different flood protection systems considered by local agencies in a test study catchment. Despite large uncertainties in damage, cost and climate, the recommendation is robust for the most conservative approach. This demonstrates the feasibility of making robust decisions under large uncertainty. Furthermore, by comparison to a previous study, it highlights the benefits of risk-based planning over the planning of flood protection to a prescribed return period.

  8. Risk-based flood protection planning under climate change and modeling uncertainty: a pre-alpine case study

    Directory of Open Access Journals (Sweden)

    B. Dittes

    2018-05-01

    Full Text Available Planning authorities are faced with a range of questions when planning flood protection measures: is the existing protection adequate for current and future demands or should it be extended? How will flood patterns change in the future? How should the uncertainty pertaining to this influence the planning decision, e.g., for delaying planning or including a safety margin? Is it sufficient to follow a protection criterion (e.g., to protect from the 100-year flood or should the planning be conducted in a risk-based way? How important is it for flood protection planning to accurately estimate flood frequency (changes, costs and damage? These are questions that we address for a medium-sized pre-alpine catchment in southern Germany, using a sequential Bayesian decision making framework that quantitatively addresses the full spectrum of uncertainty. We evaluate different flood protection systems considered by local agencies in a test study catchment. Despite large uncertainties in damage, cost and climate, the recommendation is robust for the most conservative approach. This demonstrates the feasibility of making robust decisions under large uncertainty. Furthermore, by comparison to a previous study, it highlights the benefits of risk-based planning over the planning of flood protection to a prescribed return period.

  9. Risks, uncertainty, vagueness

    International Nuclear Information System (INIS)

    Haefele, W.; Renn, O.; Erdmann, G.

    1990-01-01

    The notion of 'risk' is discussed in its social and technological contexts, leading to an investigation of the terms factuality, hypotheticality, uncertainty, and vagueness, and to the problems of acceptance and acceptability especially in the context of political decision finding. (DG) [de

  10. Strategy under uncertainty.

    Science.gov (United States)

    Courtney, H; Kirkland, J; Viguerie, P

    1997-01-01

    At the heart of the traditional approach to strategy lies the assumption that by applying a set of powerful analytic tools, executives can predict the future of any business accurately enough to allow them to choose a clear strategic direction. But what happens when the environment is so uncertain that no amount of analysis will allow us to predict the future? What makes for a good strategy in highly uncertain business environments? The authors, consultants at McKinsey & Company, argue that uncertainty requires a new way of thinking about strategy. All too often, they say, executives take a binary view: either they underestimate uncertainty to come up with the forecasts required by their companies' planning or capital-budging processes, or they overestimate it, abandon all analysis, and go with their gut instinct. The authors outline a new approach that begins by making a crucial distinction among four discrete levels of uncertainty that any company might face. They then explain how a set of generic strategies--shaping the market, adapting to it, or reserving the right to play at a later time--can be used in each of the four levels. And they illustrate how these strategies can be implemented through a combination of three basic types of actions: big bets, options, and no-regrets moves. The framework can help managers determine which analytic tools can inform decision making under uncertainty--and which cannot. At a broader level, it offers executives a discipline for thinking rigorously and systematically about uncertainty and its implications for strategy.

  11. Earnings Quality Measures and Excess Returns.

    Science.gov (United States)

    Perotti, Pietro; Wagenhofer, Alfred

    2014-06-01

    This paper examines how commonly used earnings quality measures fulfill a key objective of financial reporting, i.e., improving decision usefulness for investors. We propose a stock-price-based measure for assessing the quality of earnings quality measures. We predict that firms with higher earnings quality will be less mispriced than other firms. Mispricing is measured by the difference of the mean absolute excess returns of portfolios formed on high and low values of a measure. We examine persistence, predictability, two measures of smoothness, abnormal accruals, accruals quality, earnings response coefficient and value relevance. For a large sample of US non-financial firms over the period 1988-2007, we show that all measures except for smoothness are negatively associated with absolute excess returns, suggesting that smoothness is generally a favorable attribute of earnings. Accruals measures generate the largest spread in absolute excess returns, followed by smoothness and market-based measures. These results lend support to the widespread use of accruals measures as overall measures of earnings quality in the literature.

  12. Tempo de retorno das precipitações máximas em lavras (MG pela distribuição de valores extremos do tipo I Maximum rainfall return period by extreme values type I distribution in Lavras, Minas Gerais state, Brazil

    Directory of Open Access Journals (Sweden)

    Luiz Alberto Beijo

    2005-06-01

    Full Text Available O conhecimento das precipitações máximas prováveis é de grande importância na elaboração de projetos agrícolas e de engenharia hidráulica. Tendo em vista esse fato, objetivou-se com este trabalho determinar as estimativas pontual e intervalar da precipitação diária máxima provável para os tempos de retorno de 2, 5, 10, 20, 30, 50 e 75 anos, para períodos de quinze dias, um mês e um ano na região de Lavras (MG, utilizando-se a distribuição de valores extremos do tipo I. Aplicou-se o método da máxima verossimilhança para a estimação dos parâmetros dessa distribuição, sendo os intervalos de confiança das estimativas de precipitações máximas prováveis obtidos aplicando-se técnica de reamostragem "Jackknife". Pelos resultados, verificou-se que houve um bom ajuste da distribuição para os dados para a série anual, ao passo que na série mensal, nos meses de julho e agosto, ela não se ajustou. Para a série de quinze dias, o ajuste ocorreu apenas na estação chuvosa. Pelos resultados dos intervalos de confiança, pode-se adotar valores mais adequados de precipitação máxima no dimensionamento de obras hidráulicas na região de Lavras.The knowledge of the probable maximum rainfall is very important in the elaboration of agricultural and hydraulic engineering projects. Therefore this paper aimed to determine punctual and interval estimates of the probable maximum rainfall for return periods of 2, 5, 10, 20, 30, 50 and 75 years, at region of Lavras using the extreme values type I distribution, for periods of fifteen days, one month and one year. Maximum likelihood estimates of the parameters of the distribution were worked out. Jackknife Confidence Intervals for the estimates of probable maximum rainfall were calculated. A good fitting was observed for the annual series data; but not for the monthly, series data (specifically in july and august; and for the fifteen days series data no good model was found for the

  13. Exchange Rate Volatility, Inflation Uncertainty and Foreign Direct ...

    African Journals Online (AJOL)

    This article examines the effect of exchange rate volatility and inflation uncertainty on foreign direct investment in Nigeria. The investigation covers the period between 1970 and 2005. Exchange rate volatility and inflation uncertainty were estimated using the GARCH model. Estimation results indicated that exchange rate ...

  14. CITRICULTURE ECONOMIC AND FINANCIAL EVALUATION UNDER CONDITIONS OF UNCERTAINTY

    Directory of Open Access Journals (Sweden)

    DANILO SIMÕES

    2015-12-01

    Full Text Available ABSTRACT The citriculture consists in several environmental risks, as weather changes and pests, and also consists in considerable financial risk, mainly due to the period ofreturn on the initial investment. This study was motivated by the need to assess the risks of a business activity such as citriculture. Our objective was to build a stochastic simulation model to achieve the economic and financial analysis of an orange producer in the Midwest region of the state of Sao Paulo, under conditions of uncertainty. The parameters used were the Net Present Value (NPV, the Modified Internal Rate of Return(MIRR, and the Discounted Payback. To evaluate the risk conditions we built a probabilistic model of pseudorandom numbers generated with Monte Carlo method. The results showed that the activity analyzed provides a risk of 42.8% to reach a NPV negative; however, the yield assessed by MIRR was 7.7%, higher than the yield from the reapplication of the positive cash flows. The financial investment pays itself after the fourteenth year of activity.

  15. Earnings announcements and the variability of stock returns

    OpenAIRE

    Eilifsen, Aasmund; Knivsflå, Kjell Henry; Sættem, Frode

    1999-01-01

    This paper is concerned with the dissemination process of firm-specific annual earnings information in the Norwegian capital market. We find a significant reduction in stock price volatility in the post-announcement period relative to the pre-announcement period for companies traded on the Oslo Stock Exchange in the period 1990-1995. Potential explanations for this phenomenon are tested by relating the observed return volatility to changes in the volatility of the underlying business, the spe...

  16. No Refund or Full Refund: When Should a Fashion Brand Offer Full Refund Consumer Return Service for Mass Customization Products?

    Directory of Open Access Journals (Sweden)

    Tsan-Ming Choi

    2013-01-01

    Full Text Available We analytically explore in this paper the consumer return policy under fashion mass customization (MC program. To be specific, we model the stochastic fashion MC program with the consideration of consumer demand uncertainty. If a consumer return policy is implemented, we further consider return uncertainty. By modeling the optimization objective of the risk averse MC fashion brand via a mean-variance approach, we derive the closed-form optimal solution under each case. We then conduct both analytical and numerical sensitivity analyses. For the scenario with full refund and return, we reveal the analytical conditions under which the optimal retail price and the optimal number of options available for customization (called the “optimal modularity level” vary monotonically with respect to the salvage value and the return service charge. For the scenario when there is no refund and return, we show that the optimal retail price and the optimal modularity level are decreasing in the MC fashion brand's degree of risk aversion, the demand uncertainty, and the price-demand sensitivity coefficient. In addition, our numerical analysis indicates that whether the risk averse MC fashion brand would prefer offering consumer return with full refund to no return depends heavily on the demand-return correlation (DRC parameter.

  17. On the relationship between aerosol model uncertainty and radiative forcing uncertainty.

    Science.gov (United States)

    Lee, Lindsay A; Reddington, Carly L; Carslaw, Kenneth S

    2016-05-24

    The largest uncertainty in the historical radiative forcing of climate is caused by the interaction of aerosols with clouds. Historical forcing is not a directly measurable quantity, so reliable assessments depend on the development of global models of aerosols and clouds that are well constrained by observations. However, there has been no systematic assessment of how reduction in the uncertainty of global aerosol models will feed through to the uncertainty in the predicted forcing. We use a global model perturbed parameter ensemble to show that tight observational constraint of aerosol concentrations in the model has a relatively small effect on the aerosol-related uncertainty in the calculated forcing between preindustrial and present-day periods. One factor is the low sensitivity of present-day aerosol to natural emissions that determine the preindustrial aerosol state. However, the major cause of the weak constraint is that the full uncertainty space of the model generates a large number of model variants that are equally acceptable compared to present-day aerosol observations. The narrow range of aerosol concentrations in the observationally constrained model gives the impression of low aerosol model uncertainty. However, these multiple "equifinal" models predict a wide range of forcings. To make progress, we need to develop a much deeper understanding of model uncertainty and ways to use observations to constrain it. Equifinality in the aerosol model means that tuning of a small number of model processes to achieve model-observation agreement could give a misleading impression of model robustness.

  18. Sealed Planetary Return Canister (SPRC), Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Sample return missions have primary importance in future planetary missions. A basic requirement is that samples be returned in pristine, uncontaminated condition,...

  19. Different forms, reasons and motivations for return migration of persons who voluntarily decide to return to their countries of origin.

    Science.gov (United States)

    Callea, S

    1986-03-01

    Although the 1973 oil crisis did not have the drastic effects on immigration which were originally feared, it did end a period of quasi-liberal immigration policy, establish intense and effective international cooperation on immigration, and arouse great interest in immigration studies and research. This paper analyzes the situations arising as a result of the petroleum shortage and focuses on the conditions relating to the return of emigrants to Southern European countries. This new research draws attention to the following fundamental aspects of the immigration problem: 1) the emigrant's return to his homeland cannot be considered a factor in development; it is a positive element in development only if the right socioeconomic conditions exist in the country of origin. 2) Concern for children's education is one of the most common reasons for return. 3) A large percentage of emigrants are satisfied with their work abroad. 4) An emigrant's return potential is wasted due to the slight use that is made of the resources he offers. 5) Returning workers most often want to set up an independent enterprise. 6) Savings are generally used to buy a house or farm. 7) Vocational level does not increase significantly between emigration and returning, though this increase becomes greater the longer the emigrant stays abroad. 8) The number of returning emigrants is too slight to bring about any change in the country of origin. 9) Incentives and subsidies to encourage return have not had a considerable impact on the decision to return. Callea recommends that officials of the country of origin posted abroad be assigned to counsel returning emigrants on finding employment, attending vocational development courses, obtaining housing, accruing interests and savings, and on the problems and perspectives of sociocultural reintegration.

  20. Uncertainty in adaptive capacity

    International Nuclear Information System (INIS)

    Neil Adger, W.; Vincent, K.

    2005-01-01

    The capacity to adapt is a critical element of the process of adaptation: it is the vector of resources that represent the asset base from which adaptation actions can be made. Adaptive capacity can in theory be identified and measured at various scales, from the individual to the nation. The assessment of uncertainty within such measures comes from the contested knowledge domain and theories surrounding the nature of the determinants of adaptive capacity and the human action of adaptation. While generic adaptive capacity at the national level, for example, is often postulated as being dependent on health, governance and political rights, and literacy, and economic well-being, the determinants of these variables at national levels are not widely understood. We outline the nature of this uncertainty for the major elements of adaptive capacity and illustrate these issues with the example of a social vulnerability index for countries in Africa. (authors)

  1. Uncertainties about climate

    International Nuclear Information System (INIS)

    Laval, Katia; Laval, Guy

    2013-01-01

    Like meteorology, climatology is not an exact science: climate change forecasts necessarily include a share of uncertainty. It is precisely this uncertainty which is brandished and exploited by the opponents to the global warming theory to put into question the estimations of its future consequences. Is it legitimate to predict the future using the past climate data (well documented up to 100000 years BP) or the climates of other planets, taking into account the impreciseness of the measurements and the intrinsic complexity of the Earth's machinery? How is it possible to model a so huge and interwoven system for which any exact description has become impossible? Why water and precipitations play such an important role in local and global forecasts, and how should they be treated? This book written by two physicists answers with simpleness these delicate questions in order to give anyone the possibility to build his own opinion about global warming and the need to act rapidly

  2. The uncertainty principle

    International Nuclear Information System (INIS)

    Martens, Hans.

    1991-01-01

    The subject of this thesis is the uncertainty principle (UP). The UP is one of the most characteristic points of differences between quantum and classical mechanics. The starting point of this thesis is the work of Niels Bohr. Besides the discussion the work is also analyzed. For the discussion of the different aspects of the UP the formalism of Davies and Ludwig is used instead of the more commonly used formalism of Neumann and Dirac. (author). 214 refs.; 23 figs

  3. Uncertainty in artificial intelligence

    CERN Document Server

    Shachter, RD; Henrion, M; Lemmer, JF

    1990-01-01

    This volume, like its predecessors, reflects the cutting edge of research on the automation of reasoning under uncertainty.A more pragmatic emphasis is evident, for although some papers address fundamental issues, the majority address practical issues. Topics include the relations between alternative formalisms (including possibilistic reasoning), Dempster-Shafer belief functions, non-monotonic reasoning, Bayesian and decision theoretic schemes, and new inference techniques for belief nets. New techniques are applied to important problems in medicine, vision, robotics, and natural language und

  4. Decision Making Under Uncertainty

    Science.gov (United States)

    2010-11-01

    A sound approach to rational decision making requires a decision maker to establish decision objectives, identify alternatives, and evaluate those...often violate the axioms of rationality when making decisions under uncertainty. The systematic description of such observations may lead to the...which leads to “anchoring” on the initial value. The fact that individuals have been shown to deviate from rationality when making decisions

  5. Economic uncertainty principle?

    OpenAIRE

    Alexander Harin

    2006-01-01

    The economic principle of (hidden) uncertainty is presented. New probability formulas are offered. Examples of solutions of three types of fundamental problems are reviewed.; Principe d'incertitude économique? Le principe économique d'incertitude (cachée) est présenté. De nouvelles formules de chances sont offertes. Les exemples de solutions des trois types de problèmes fondamentaux sont reconsidérés.

  6. Citizen Candidates Under Uncertainty

    OpenAIRE

    Eguia, Jon X.

    2005-01-01

    In this paper we make two contributions to the growing literature on "citizen-candidate" models of representative democracy. First, we add uncertainty about the total vote count. We show that in a society with a large electorate, where the outcome of the election is uncertain and where winning candidates receive a large reward from holding office, there will be a two-candidate equilibrium and no equilibria with a single candidate. Second, we introduce a new concept of equilibrium, which we te...

  7. Experiences of occupational therapists returning to work after maternity leave.

    Science.gov (United States)

    Parcsi, Lisa; Curtin, Michael

    2013-08-01

    Returning to work after maternity leave can be a challenging, anxious and fraught experience for women, and has been portrayed in the literature as a generally negative experience. Interestingly, although occupational therapists were predominantly women, no research was found focussing on their experiences of returning to work after maternity leave. The aim of this research was to gain an insight into occupational therapists' experiences of returning to work following maternity leave. Principles of interpretive phenomenological analysis were used to explore the individual experiences of six Australian occupational therapists returning to work after a period of maternity leave. Individual semi-structured interviews lasting up to 90 minutes were conducted. Interviews were audio-recorded, transcribed and then analysed. Two major themes emerged from the analysis of interviews: compromise and feeling valued. The experience of returning to work was a process of compromise in which women found strategies to cope with their changing roles and demands, to find a balance between home and work life. The women wanted to feel valued by their managers and co-workers, as this enabled them to feel comfortable and confident with some of the compromises they made. Occupational therapists returning to work after maternity leave will make compromises so that they can balance their home and work life. Occupational therapists value managers and co-workers who understand the compromises women make when returning to work following maternity leave and who create a supportive workplace that acknowledges and values their contribution. © 2013 Occupational Therapy Australia.

  8. Leaving from and returning to nursing practice: contributing factors.

    Science.gov (United States)

    Jamieson, Isabel; Taua, Chris

    2009-07-01

    Many nurses leave nursing and never return. Others return after a period of time. Given the global shortage of nurses a better understanding of these movements is needed. The present study focused on nurses who had been out of nursing for more than five years, and explored factors that influenced their leaving and return to practice. All the nurses who had undertaken a Competency Assessment Programme at a given New Zealand tertiary institution during 2005 were invited to participate. Of the 70 questionnaires mailed out 32 (44.5%) were completed and returned. Quantitative data were analysed using Microsoft Excel, and the qualitative data were coded and analysed by means of content analysis. For each, leaving and returning, three key issues emerged. Nurses left for personal reasons, to seek a career change, or because of poor working conditions. They returned when they had the personal freedom to do so, for fiscal reasons, or because they were motivated by some sense of unfinished business. These findings indicate that it is important for educators involved with Competency Assessment Programmes to collaborate with employers in ensuring that there are opportunities for re-entry to positive work environments, with a degree of flexibility that suits the demographic characteristics of those nurses returning to practice.

  9. Weibo sentiments and stock return: A time-frequency view.

    Science.gov (United States)

    Xu, Yingying; Liu, Zhixin; Zhao, Jichang; Su, Chiwei

    2017-01-01

    This study provides new insights into the relationships between social media sentiments and the stock market in China. Based on machine learning, we classify microblogs posted on Sina Weibo, a Twitter's variant in China into five detailed sentiments of anger, disgust, fear, joy, and sadness. Using wavelet analysis, we find close positive linkages between sentiments and the stock return, which have both frequency and time-varying features. Five detailed sentiments are positively related to the stock return for certain periods, particularly since October 2014 at medium to high frequencies of less than ten trading days, when the stock return is undergoing significant fluctuations. Sadness appears to have a closer relationship with the stock return than the other four sentiments. As to the lead-lag relationships, the stock return causes Weibo sentiments rather than reverse for most of the periods with significant linkages. Compared with polarity sentiments (negative vs. positive), detailed sentiments provide more information regarding relationships between Weibo sentiments and the stock market. The stock market exerts positive effects on bullishness and agreement of microblogs. Meanwhile, agreement leads the stock return in-phase at the frequency of approximately 40 trading days, indicating that less disagreement improves certainty about the stock market.

  10. Weibo sentiments and stock return: A time-frequency view.

    Directory of Open Access Journals (Sweden)

    Yingying Xu

    Full Text Available This study provides new insights into the relationships between social media sentiments and the stock market in China. Based on machine learning, we classify microblogs posted on Sina Weibo, a Twitter's variant in China into five detailed sentiments of anger, disgust, fear, joy, and sadness. Using wavelet analysis, we find close positive linkages between sentiments and the stock return, which have both frequency and time-varying features. Five detailed sentiments are positively related to the stock return for certain periods, particularly since October 2014 at medium to high frequencies of less than ten trading days, when the stock return is undergoing significant fluctuations. Sadness appears to have a closer relationship with the stock return than the other four sentiments. As to the lead-lag relationships, the stock return causes Weibo sentiments rather than reverse for most of the periods with significant linkages. Compared with polarity sentiments (negative vs. positive, detailed sentiments provide more information regarding relationships between Weibo sentiments and the stock market. The stock market exerts positive effects on bullishness and agreement of microblogs. Meanwhile, agreement leads the stock return in-phase at the frequency of approximately 40 trading days, indicating that less disagreement improves certainty about the stock market.

  11. Weibo sentiments and stock return: A time-frequency view

    Science.gov (United States)

    Liu, Zhixin; Zhao, Jichang; Su, Chiwei

    2017-01-01

    This study provides new insights into the relationships between social media sentiments and the stock market in China. Based on machine learning, we classify microblogs posted on Sina Weibo, a Twitter’s variant in China into five detailed sentiments of anger, disgust, fear, joy, and sadness. Using wavelet analysis, we find close positive linkages between sentiments and the stock return, which have both frequency and time-varying features. Five detailed sentiments are positively related to the stock return for certain periods, particularly since October 2014 at medium to high frequencies of less than ten trading days, when the stock return is undergoing significant fluctuations. Sadness appears to have a closer relationship with the stock return than the other four sentiments. As to the lead-lag relationships, the stock return causes Weibo sentiments rather than reverse for most of the periods with significant linkages. Compared with polarity sentiments (negative vs. positive), detailed sentiments provide more information regarding relationships between Weibo sentiments and the stock market. The stock market exerts positive effects on bullishness and agreement of microblogs. Meanwhile, agreement leads the stock return in-phase at the frequency of approximately 40 trading days, indicating that less disagreement improves certainty about the stock market. PMID:28672026

  12. Calibration Under Uncertainty.

    Energy Technology Data Exchange (ETDEWEB)

    Swiler, Laura Painton; Trucano, Timothy Guy

    2005-03-01

    This report is a white paper summarizing the literature and different approaches to the problem of calibrating computer model parameters in the face of model uncertainty. Model calibration is often formulated as finding the parameters that minimize the squared difference between the model-computed data (the predicted data) and the actual experimental data. This approach does not allow for explicit treatment of uncertainty or error in the model itself: the model is considered the %22true%22 deterministic representation of reality. While this approach does have utility, it is far from an accurate mathematical treatment of the true model calibration problem in which both the computed data and experimental data have error bars. This year, we examined methods to perform calibration accounting for the error in both the computer model and the data, as well as improving our understanding of its meaning for model predictability. We call this approach Calibration under Uncertainty (CUU). This talk presents our current thinking on CUU. We outline some current approaches in the literature, and discuss the Bayesian approach to CUU in detail.

  13. Participation under Uncertainty

    International Nuclear Information System (INIS)

    Boudourides, Moses A.

    2003-01-01

    This essay reviews a number of theoretical perspectives about uncertainty and participation in the present-day knowledge-based society. After discussing the on-going reconfigurations of science, technology and society, we examine how appropriate for policy studies are various theories of social complexity. Post-normal science is such an example of a complexity-motivated approach, which justifies civic participation as a policy response to an increasing uncertainty. But there are different categories and models of uncertainties implying a variety of configurations of policy processes. A particular role in all of them is played by expertise whose democratization is an often-claimed imperative nowadays. Moreover, we discuss how different participatory arrangements are shaped into instruments of policy-making and framing regulatory processes. As participation necessitates and triggers deliberation, we proceed to examine the role and the barriers of deliberativeness. Finally, we conclude by referring to some critical views about the ultimate assumptions of recent European policy frameworks and the conceptions of civic participation and politicization that they invoke

  14. Uncertainty analysis techniques

    International Nuclear Information System (INIS)

    Marivoet, J.; Saltelli, A.; Cadelli, N.

    1987-01-01

    The origin of the uncertainty affecting Performance Assessments, as well as their propagation to dose and risk results is discussed. The analysis is focused essentially on the uncertainties introduced by the input parameters, the values of which may range over some orders of magnitude and may be given as probability distribution function. The paper briefly reviews the existing sampling techniques used for Monte Carlo simulations and the methods for characterizing the output curves, determining their convergence and confidence limits. Annual doses, expectation values of the doses and risks are computed for a particular case of a possible repository in clay, in order to illustrate the significance of such output characteristics as the mean, the logarithmic mean and the median as well as their ratios. The report concludes that provisionally, due to its better robustness, such estimation as the 90th percentile may be substituted to the arithmetic mean for comparison of the estimated doses with acceptance criteria. In any case, the results obtained through Uncertainty Analyses must be interpreted with caution as long as input data distribution functions are not derived from experiments reasonably reproducing the situation in a well characterized repository and site

  15. Deterministic uncertainty analysis

    International Nuclear Information System (INIS)

    Worley, B.A.

    1987-12-01

    This paper presents a deterministic uncertainty analysis (DUA) method for calculating uncertainties that has the potential to significantly reduce the number of computer runs compared to conventional statistical analysis. The method is based upon the availability of derivative and sensitivity data such as that calculated using the well known direct or adjoint sensitivity analysis techniques. Formation of response surfaces using derivative data and the propagation of input probability distributions are discussed relative to their role in the DUA method. A sample problem that models the flow of water through a borehole is used as a basis to compare the cumulative distribution function of the flow rate as calculated by the standard statistical methods and the DUA method. Propogation of uncertainties by the DUA method is compared for ten cases in which the number of reference model runs was varied from one to ten. The DUA method gives a more accurate representation of the true cumulative distribution of the flow rate based upon as few as two model executions compared to fifty model executions using a statistical approach. 16 refs., 4 figs., 5 tabs

  16. Uncertainty contributions to low flow projections in Austria

    Science.gov (United States)

    Parajka, J.; Blaschke, A. P.; Blöschl, G.; Haslinger, K.; Hepp, G.; Laaha, G.; Schöner, W.; Trautvetter, H.; Viglione, A.; Zessner, M.

    2015-11-01

    The main objective of the paper is to understand the contributions to the uncertainty in low flow projections resulting from hydrological model uncertainty and climate projection uncertainty. Model uncertainty is quantified by different parameterizations of a conceptual semi-distributed hydrologic model (TUWmodel) using 11 objective functions in three different decades (1976-1986, 1987-1997, 1998-2008), which allows disentangling the effect of modeling uncertainty and temporal stability of model parameters. Climate projection uncertainty is quantified by four future climate scenarios (ECHAM5-A1B, A2, B1 and HADCM3-A1B) using a delta change approach. The approach is tested for 262 basins in Austria. The results indicate that the seasonality of the low flow regime is an important factor affecting the performance of model calibration in the reference period and the uncertainty of Q95 low flow projections in the future period. In Austria, the calibration uncertainty in terms of Q95 is larger in basins with summer low flow regime than in basins with winter low flow regime. Using different calibration periods may result in a range of up to 60 % in simulated Q95 low flows. The low flow projections show an increase of low flows in the Alps, typically in the range of 10-30 % and a decrease in the south-eastern part of Austria mostly in the range -5 to -20 % for the period 2021-2050 relative the reference period 1976-2008. The change in seasonality varies between scenarios, but there is a tendency for earlier low flows in the Northern Alps and later low flows in Eastern Austria. In 85 % of the basins, the uncertainty in Q95 from model calibration is larger than the uncertainty from different climate scenarios. The total uncertainty of Q95 projections is the largest in basins with winter low flow regime and, in some basins, exceeds 60 %. In basins with summer low flows and the total uncertainty is mostly less than 20 %. While the calibration uncertainty dominates over climate

  17. Abnormal Returns and Contrarian Strategies

    Directory of Open Access Journals (Sweden)

    Ivana Dall'Agnol

    2003-12-01

    Full Text Available We test the hypothesis that strategies which are long on portfolios of looser stocks and short on portfolios of winner stocks generate abnormal returns in Brazil. This type of evidence for the US stock market was interpreted by The Bondt and Thaler (1985 as reflecting systematic evaluation mistakes caused by investors overreaction to news related to the firm performance. We found evidence of contrarian strategies profitability for horizons from 3 months to 3 years in a sample of stock returns from BOVESPA and SOMA from 1986 to 2000. The strategies are more profitable for shorter horizons. Therefore, there was no trace of the momentum effect found by Jagadeesh and Titman (1993 for the same horizons with US data. There are remaing unexplained positive returns for contrarian strategies after accounting for risk, size, and liquidity. We also found that the strategy profitability is reduced after the Real Plan, which suggests that the Brazilian stock market became more efficient after inflation stabilization.

  18. Rehabilitation and return to sport after hamstring strain injury

    Directory of Open Access Journals (Sweden)

    Lauren N. Erickson

    2017-09-01

    Full Text Available Hamstring strain injuries are common among sports that involve sprinting, kicking, and high-speed skilled movements or extensive muscle lengthening-type maneuvers with hip flexion and knee extension. These injuries present the challenge of significant recovery time and a lengthy period of increased susceptibility for recurrent injury. Nearly one third of hamstring strains recur within the first year following return to sport with subsequent injuries often being more severe than the original. This high re-injury rate suggests that athletes may be returning to sport prematurely due to inadequate return to sport criteria. In this review article, we describe the epidemiology, risk factors, differential diagnosis, and prognosis of an acute hamstring strain. Based on the current available evidence, we then propose a clinical guide for the rehabilitation of acute hamstring strains and an algorithm to assist clinicians in the decision-making process when assessing readiness of an athlete to return to sport.

  19. Dynamic returns of beta arbitrage

    OpenAIRE

    Nascimento, Mafalda

    2017-01-01

    This thesis studies the patterns of the abnormal returns of the beta strategy. The topic can be helpful for professional investors, who intend to achieve a better performance in their portfolios. Following the methodology of Lou, Polk, & Huang (2016), the COBAR measure is computed in order to determine the levels of beta arbitrage in the market in each point in time. It is argued that beta arbitrage activity can have impact on the returns of the beta strategy. In fact, it is demonstrated that...

  20. Sovereign Risk and Currently Returns

    DEFF Research Database (Denmark)

    Della Corte, Pasquale; Sarno, Lucio; Schmeling, Maik

    We empirically investigate the relation between sovereign risk and exchange rates for a broad set of currencies. An increase in the credit default swap (CDS) spread of a country is accompanied by a significant depreciation of the exchange rate. More generally, CDS spread changes have substantial...... explanatory power for currency returns which is largely driven by shocks to global credit risk. Consistent with the notion that sovereign risk is priced, we find that a country's exposure to global credit risk forecasts excess returns to trading exchange rates as well as to trading on the volatility, skewness...

  1. Sovereign Risk and Currency Returns

    DEFF Research Database (Denmark)

    Della Corte, Pasquale; Sarno, Lucio; Schmeling, Maik

    We empirically investigate the relation between sovereign risk and exchange rates for a broad set of currencies. An increase in the credit default swap (CDS) spread of a country is accompanied by a significant depreciation of the exchange rate. More generally, CDS spread changes have substantial...... explanatory power for currency returns which is largely driven by shocks to global credit risk. Consistent with the notion that sovereign risk is priced, we find that a country's exposure to global credit risk forecasts excess returns to trading exchange rates as well as to trading on the volatility, skewness...

  2. Methodologies of Uncertainty Propagation Calculation

    International Nuclear Information System (INIS)

    Chojnacki, Eric

    2002-01-01

    After recalling the theoretical principle and the practical difficulties of the methodologies of uncertainty propagation calculation, the author discussed how to propagate input uncertainties. He said there were two kinds of input uncertainty: - variability: uncertainty due to heterogeneity, - lack of knowledge: uncertainty due to ignorance. It was therefore necessary to use two different propagation methods. He demonstrated this in a simple example which he generalised, treating the variability uncertainty by the probability theory and the lack of knowledge uncertainty by the fuzzy theory. He cautioned, however, against the systematic use of probability theory which may lead to unjustifiable and illegitimate precise answers. Mr Chojnacki's conclusions were that the importance of distinguishing variability and lack of knowledge increased as the problem was getting more and more complex in terms of number of parameters or time steps, and that it was necessary to develop uncertainty propagation methodologies combining probability theory and fuzzy theory

  3. LOFT uncertainty-analysis methodology

    International Nuclear Information System (INIS)

    Lassahn, G.D.

    1983-01-01

    The methodology used for uncertainty analyses of measurements in the Loss-of-Fluid Test (LOFT) nuclear-reactor-safety research program is described and compared with other methodologies established for performing uncertainty analyses

  4. LOFT uncertainty-analysis methodology

    International Nuclear Information System (INIS)

    Lassahn, G.D.

    1983-01-01

    The methodology used for uncertainty analyses of measurements in the Loss-of-Fluid Test (LOFT) nuclear reactor safety research program is described and compared with other methodologies established for performing uncertainty analyses

  5. Assessing River Low-Flow Uncertainties Related to Hydrological Model Calibration and Structure under Climate Change Conditions

    Directory of Open Access Journals (Sweden)

    Mélanie Trudel

    2017-03-01

    Full Text Available Low-flow is the flow of water in a river during prolonged dry weather. This paper investigated the uncertainty originating from hydrological model calibration and structure in low-flow simulations under climate change conditions. Two hydrological models of contrasting complexity, GR4J and SWAT, were applied to four sub-watersheds of the Yamaska River, Canada. The two models were calibrated using seven different objective functions including the Nash-Sutcliffe coefficient (NSEQ and six other objective functions more related to low flows. The uncertainty in the model parameters was evaluated using a PARAmeter SOLutions procedure (PARASOL. Twelve climate projections from different combinations of General Circulation Models (GCMs and Regional Circulation Models (RCMs were used to simulate low-flow indices in a reference (1970–2000 and future (2040–2070 horizon. Results indicate that the NSEQ objective function does not properly represent low-flow indices for either model. The NSE objective function applied to the log of the flows shows the lowest total variance for all sub-watersheds. In addition, these hydrological models should be used with care for low-flow studies, since they both show some inconsistent results. The uncertainty is higher for SWAT than for GR4J. With GR4J, the uncertainties in the simulations for the 7Q2 index (the 7-day low-flow value with a 2-year return period are lower for the future period than for the reference period. This can be explained by the analysis of hydrological processes. In the future horizon, a significant worsening of low-flow conditions was projected.

  6. Impact of the spatial structure on the returns of the stock indexes

    Directory of Open Access Journals (Sweden)

    Carlos A. Díaz Contreras

    2007-09-01

    Full Text Available Nowadays, economies are integrated in commercial, financial, social, and cultural terms. Integration facilitates the transmission of impacts associated with economic events originated in one region to other regions, generating unexpected fluctuations at domestic level. Hence, investors may face higher uncertainty and unexpected effects on economic development may be observed. This research shows a significant spatial dependence in stock returns for the America’s countries. Therefore, we demonstrate that there exist spatial externalities, which facilitate that changes affecting to stock returns of each country are spread through the continent, impacting also to the rest of American countries’ returns.

  7. Do Orthopaedic Surgeons Acknowledge Uncertainty?

    NARCIS (Netherlands)

    Teunis, Teun; Janssen, Stein; Guitton, Thierry G.; Ring, David; Parisien, Robert

    2016-01-01

    Much of the decision-making in orthopaedics rests on uncertain evidence. Uncertainty is therefore part of our normal daily practice, and yet physician uncertainty regarding treatment could diminish patients' health. It is not known if physician uncertainty is a function of the evidence alone or if

  8. Comet coma sample return instrument

    Science.gov (United States)

    Albee, A. L.; Brownlee, Don E.; Burnett, Donald S.; Tsou, Peter; Uesugi, K. T.

    1994-01-01

    The sample collection technology and instrument concept for the Sample of Comet Coma Earth Return Mission (SOCCER) are described. The scientific goals of this Flyby Sample Return are to return to coma dust and volatile samples from a known comet source, which will permit accurate elemental and isotopic measurements for thousands of individual solid particles and volatiles, detailed analysis of the dust structure, morphology, and mineralogy of the intact samples, and identification of the biogenic elements or compounds in the solid and volatile samples. Having these intact samples, morphologic, petrographic, and phase structural features can be determined. Information on dust particle size, shape, and density can be ascertained by analyzing penetration holes and tracks in the capture medium. Time and spatial data of dust capture will provide understanding of the flux dynamics of the coma and the jets. Additional information will include the identification of cosmic ray tracks in the cometary grains, which can provide a particle's process history and perhaps even the age of the comet. The measurements will be made with the same equipment used for studying micrometeorites for decades past; hence, the results can be directly compared without extrapolation or modification. The data will provide a powerful and direct technique for comparing the cometary samples with all known types of meteorites and interplanetary dust. This sample collection system will provide the first sample return from a specifically identified primitive body and will allow, for the first time, a direct method of matching meteoritic materials captured on Earth with known parent bodies.

  9. Uncertainty Analysis and Overtopping Risk Evaluation of Maroon Dam withMonte Carlo and Latin Hypercube Methods

    Directory of Open Access Journals (Sweden)

    J. M. Vali Samani

    2016-02-01

    . As it can be seen, the risk curves computed by the LHS are slightly higher than those curves computed by the MCS method. Also as it is observed, the differences between risk values of the two methods increase in longer return periods. Variations of overtopping risk with increasing the initial water level and return period related to overtopping risk in the 2-year return period for the initial water level of 470 m are shown in Table1. The results show that elongation of return period plays a more important role in increasing the risk, than the increase of initial water level. T\tMethod\t2→2\t2→50\t2→100\t2→1000\t2→5000\t2→10000 470→470\tMCS\t1\t5\t9\t23\t42.36\t58 470→478 2\t7\t15.6\t37\t58.34\t79 470→485 5.6\t13.6\t28.6\t55.6\t85.67\t112.6 470→493 10.3\t32.6\t54\t95.6\t127.34\t152 470→504 40.3\t83\t117.3\t165\t200.34\t224.3 470→470\tLHS\t1\t5.34\t11\t25.3\t43\t60.3 470→478 2.3\t8.6\t18\t39.3\t60.67\t84 470→485 5.3\t17.3\t32.6\t58.3\t89\t114.6 470→493 13.3\t37.6\t57.6\t97\t133.34\t160.3 470→504 41.6\t87.3\t119.6\t173\t205\t233.3 Figure 2- Overtopping risk in the initial water level of 504 m, without considering the wind effect Conclusions: This study applies MCS and LHS methods to analyze the uncertainty and evaluate the dam overtopping risk consideringthe uncertainties in input variables, such as quintile of flood peak discharge, initial levels of water and spill coefficients. The results show that the uncertainty of water level calculated by MCS is higher than that calculated by LHS. In addition, the overtopping risk calculated by LHS is higher than that calculated by MCS. Furthermore, the increase of inflow rate influences the variations of the overtopping risk more than the increase of the return period. In addition, evaluation of the results indicates that the overtopping risk is an important issue in the Maroon dam. So, a comprehensiverisk analysis procedure in conjunction with uncertainty gives very important information for

  10. Phobos Sample Return: Next Approach

    Science.gov (United States)

    Zelenyi, Lev; Martynov, Maxim; Zakharov, Alexander; Korablev, Oleg; Ivanov, Alexey; Karabadzak, George

    The Martian moons still remain a mystery after numerous studies by Mars orbiting spacecraft. Their study cover three major topics related to (1) Solar system in general (formation and evolution, origin of planetary satellites, origin and evolution of life); (2) small bodies (captured asteroid, or remnants of Mars formation, or reaccreted Mars ejecta); (3) Mars (formation and evolution of Mars; Mars ejecta at the satellites). As reviewed by Galimov [2010] most of the above questions require the sample return from the Martian moon, while some (e.g. the characterization of the organic matter) could be also answered by in situ experiments. There is the possibility to obtain the sample of Mars material by sampling Phobos: following to Chappaz et al. [2012] a 200-g sample could contain 10-7 g of Mars surface material launched during the past 1 mln years, or 5*10-5 g of Mars material launched during the past 10 mln years, or 5*1010 individual particles from Mars, quantities suitable for accurate laboratory analyses. The studies of Phobos have been of high priority in the Russian program on planetary research for many years. Phobos-88 mission consisted of two spacecraft (Phobos-1, Phobos-2) and aimed the approach to Phobos at 50 m and remote studies, and also the release of small landers (long-living stations DAS). This mission implemented the program incompletely. It was returned information about the Martian environment and atmosphere. The next profect Phobos Sample Return (Phobos-Grunt) initially planned in early 2000 has been delayed several times owing to budget difficulties; the spacecraft failed to leave NEO in 2011. The recovery of the science goals of this mission and the delivery of the samples of Phobos to Earth remain of highest priority for Russian scientific community. The next Phobos SR mission named Boomerang was postponed following the ExoMars cooperation, but is considered the next in the line of planetary exploration, suitable for launch around 2022. A

  11. Investment and uncertainty

    DEFF Research Database (Denmark)

    Greasley, David; Madsen, Jakob B.

    2006-01-01

    A severe collapse of fixed capital formation distinguished the onset of the Great Depression from other investment downturns between the world wars. Using a model estimated for the years 1890-2000, we show that the expected profitability of capital measured by Tobin's q, and the uncertainty...... surrounding expected profits indicated by share price volatility, were the chief influences on investment levels, and that heightened share price volatility played the dominant role in the crucial investment collapse in 1930. Investment did not simply follow the downward course of income at the onset...

  12. Optimization under Uncertainty

    KAUST Repository

    Lopez, Rafael H.

    2016-01-06

    The goal of this poster is to present the main approaches to optimization of engineering systems in the presence of uncertainties. We begin by giving an insight about robust optimization. Next, we detail how to deal with probabilistic constraints in optimization, the so called the reliability based design. Subsequently, we present the risk optimization approach, which includes the expected costs of failure in the objective function. After that the basic description of each approach is given, the projects developed by CORE are presented. Finally, the main current topic of research of CORE is described.

  13. Optimizing production under uncertainty

    DEFF Research Database (Denmark)

    Rasmussen, Svend

    This Working Paper derives criteria for optimal production under uncertainty based on the state-contingent approach (Chambers and Quiggin, 2000), and discusses po-tential problems involved in applying the state-contingent approach in a normative context. The analytical approach uses the concept...... of state-contingent production functions and a definition of inputs including both sort of input, activity and alloca-tion technology. It also analyses production decisions where production is combined with trading in state-contingent claims such as insurance contracts. The final part discusses...

  14. Commonplaces and social uncertainty

    DEFF Research Database (Denmark)

    Lassen, Inger

    2008-01-01

    This article explores the concept of uncertainty in four focus group discussions about genetically modified food. In the discussions, members of the general public interact with food biotechnology scientists while negotiating their attitudes towards genetic engineering. Their discussions offer...... an example of risk discourse in which the use of commonplaces seems to be a central feature (Myers 2004: 81). My analyses support earlier findings that commonplaces serve important interactional purposes (Barton 1999) and that they are used for mitigating disagreement, for closing topics and for facilitating...

  15. Principles of Uncertainty

    CERN Document Server

    Kadane, Joseph B

    2011-01-01

    An intuitive and mathematical introduction to subjective probability and Bayesian statistics. An accessible, comprehensive guide to the theory of Bayesian statistics, Principles of Uncertainty presents the subjective Bayesian approach, which has played a pivotal role in game theory, economics, and the recent boom in Markov Chain Monte Carlo methods. Both rigorous and friendly, the book contains: Introductory chapters examining each new concept or assumption Just-in-time mathematics -- the presentation of ideas just before they are applied Summary and exercises at the end of each chapter Discus

  16. Mathematical Analysis of Uncertainty

    Directory of Open Access Journals (Sweden)

    Angel GARRIDO

    2016-01-01

    Full Text Available Classical Logic showed early its insufficiencies for solving AI problems. The introduction of Fuzzy Logic aims at this problem. There have been research in the conventional Rough direction alone or in the Fuzzy direction alone, and more recently, attempts to combine both into Fuzzy Rough Sets or Rough Fuzzy Sets. We analyse some new and powerful tools in the study of Uncertainty, as the Probabilistic Graphical Models, Chain Graphs, Bayesian Networks, and Markov Networks, integrating our knowledge of graphs and probability.

  17. Insider Trading Activities and Returns of German Blue Chips

    Directory of Open Access Journals (Sweden)

    Dagmar Linnertová

    2015-01-01

    Full Text Available The aim of this paper is to investigate the causality between stock returns and insider open market transactions. The Dumitrescu-Hurlin (2012 heterogeneous approach to panel Granger causality is chosen to examine the relationship. The investigation is conducted on the 30 most traded German blue chips during the period of 2006–2014. The strong causality is revealed in the one-month period. Thus, stock returns may be used to predict future insider trading activity. The strong causality between stock returns and future insider buying and selling transactions is further confirmed with three out of four employed insider trading indices. The fact of the legal insider trade (either buy or sell is more important than its volume. The reverse relationship is weak and valid only for longer time horizon of twelve months. Our results indicate that insider traders do not degrade the market efficiency in the long run.

  18. Probability distribution of extreme share returns in Malaysia

    Science.gov (United States)

    Zin, Wan Zawiah Wan; Safari, Muhammad Aslam Mohd; Jaaman, Saiful Hafizah; Yie, Wendy Ling Shin

    2014-09-01

    The objective of this study is to investigate the suitable probability distribution to model the extreme share returns in Malaysia. To achieve this, weekly and monthly maximum daily share returns are derived from share prices data obtained from Bursa Malaysia over the period of 2000 to 2012. The study starts with summary statistics of the data which will provide a clue on the likely candidates for the best fitting distribution. Next, the suitability of six extreme value distributions, namely the Gumbel, Generalized Extreme Value (GEV), Generalized Logistic (GLO) and Generalized Pareto (GPA), the Lognormal (GNO) and the Pearson (PE3) distributions are evaluated. The method of L-moments is used in parameter estimation. Based on several goodness of fit tests and L-moment diagram test, the Generalized Pareto distribution and the Pearson distribution are found to be the best fitted distribution to represent the weekly and monthly maximum share returns in Malaysia stock market during the studied period, respectively.

  19. Erosividade, padrões hidrológicos, período de retorno e probabilidade de ocorrência das chuvas em São Borja, RS Erosivity, hydrological patterns, return period and probability of occurrence of rainfalls at São Borja, RS, Brazil

    Directory of Open Access Journals (Sweden)

    Elemar Antonino Cassol

    2008-06-01

    "R" da USLE, foi obtido de dados pluviométricos, representados pelo coeficiente de chuva, que pode ser utilizado para regiões climáticas semelhantes que apenas dispõem de dados pluviométricos. O valor da erosividade média anual de 9.751 MJ mm ha-1 h-1 ano-1 é esperado pelo menos uma vez a cada 2,2 anos, com uma probabilidade de ocorrência de 44,9 %.The erosivity potential of rainfalls can be estimated by some indexes, among them the EI30, which is given by the product of kinetic energy (E and rainfall intensity for a 30-minute period (I30. The purpose of this study was to determine rainfall erosivity, hydrological patterns, return period and probability of occurrence of erosive rainfalls in São Borja, RS, Brazil, based on diary rainfall charts of the FEPAGRO meteorological station, from 1956 to 2003. The duration and accumulated amount of each erosive rainfall were measured, entered in a spreadsheet, digitalized and processed by CHUVEROS software, which calculated the EI30 index and the monthly and annual total erosivity, besides determining the hydrological pattern of each rainfall. Most of the annual erosivity (76 % was concentrated between October and April, in the period of soil tillage, sowing and growth of summer crops. The most notable peak in the erosive potential was observed between March and April (1,260-1,269 MJ mm ha-1 h-1, when most crops are normally in full growth, while July and August were the months of lowest erosive potential (268-271 MJ mm ha-1 h-1. Of the total erosive rainfalls 47, 25 and 28 % had advanced, intermediary and delayed patterns, respectively, while these patterns corresponded to 50, 26 and 24 %, respectively, of the mean annual volume of erosive rainfalls and to 53, 25 and 22 % of the average annual erosivity. The mean annual index of erosivity in São Borja is 9,751 MJ mm ha-1 h-1 year-1. It represents the "R" Factor of the Universal Soil Loss Equation to be used in São Borja and regions with similar rainfall pattern

  20. Do dividend shocks affect excess returns? An experimental study

    Directory of Open Access Journals (Sweden)

    Draganac Dragana

    2017-01-01

    Full Text Available The dividend announcement of a company is an informational event that can cause underreaction, momentum, overreaction, post-dividend announcement drift, and mean reversion. It is the uncertainty surrounding dividend announcements that leads to such behavioural phenomena. Most authors consider that underreaction occurs after dividend shocks because new information about the dividend is being slowly and gradually built into the stock price. The effect of dividend shocks is often reflected in excess returns, which can last up to one year after the shock. The experiment described in this paper tests whether statistically significant excess returns are realized after a shock dividend announcement. Participants trade with the stocks of two companies, which only differ by dividend-generating stochastic process. The dividend process of Company 2 is a Merton-style jump-diffusion process (consisting of two parts: Brownian motion and Poisson jump, while the dividend process of Company 1 contains only the Brownian motion component. Statistically significant excess returns are expected when trading with Company 2 stocks. An autoregressive model is applied in order to test this hypothesis. The conclusion is that a dividend shock is followed by statistically significant excess returns in 20 of the 22 experiments, which implies that markets are inefficient after sudden and large changes in dividends. Underreaction and discount rate effects are identified.

  1. Investment, regulation, and uncertainty

    Science.gov (United States)

    Smyth, Stuart J; McDonald, Jillian; Falck-Zepeda, Jose

    2014-01-01

    As with any technological innovation, time refines the technology, improving upon the original version of the innovative product. The initial GM crops had single traits for either herbicide tolerance or insect resistance. Current varieties have both of these traits stacked together and in many cases other abiotic and biotic traits have also been stacked. This innovation requires investment. While this is relatively straight forward, certain conditions need to exist such that investments can be facilitated. The principle requirement for investment is that regulatory frameworks render consistent and timely decisions. If the certainty of regulatory outcomes weakens, the potential for changes in investment patterns increases.   This article provides a summary background to the leading plant breeding technologies that are either currently being used to develop new crop varieties or are in the pipeline to be applied to plant breeding within the next few years. Challenges for existing regulatory systems are highlighted. Utilizing an option value approach from investment literature, an assessment of uncertainty regarding the regulatory approval for these varying techniques is undertaken. This research highlights which technology development options have the greatest degree of uncertainty and hence, which ones might be expected to see an investment decline. PMID:24499745

  2. Probabilistic Mass Growth Uncertainties

    Science.gov (United States)

    Plumer, Eric; Elliott, Darren

    2013-01-01

    Mass has been widely used as a variable input parameter for Cost Estimating Relationships (CER) for space systems. As these space systems progress from early concept studies and drawing boards to the launch pad, their masses tend to grow substantially, hence adversely affecting a primary input to most modeling CERs. Modeling and predicting mass uncertainty, based on historical and analogous data, is therefore critical and is an integral part of modeling cost risk. This paper presents the results of a NASA on-going effort to publish mass growth datasheet for adjusting single-point Technical Baseline Estimates (TBE) of masses of space instruments as well as spacecraft, for both earth orbiting and deep space missions at various stages of a project's lifecycle. This paper will also discusses the long term strategy of NASA Headquarters in publishing similar results, using a variety of cost driving metrics, on an annual basis. This paper provides quantitative results that show decreasing mass growth uncertainties as mass estimate maturity increases. This paper's analysis is based on historical data obtained from the NASA Cost Analysis Data Requirements (CADRe) database.

  3. Embracing uncertainty in applied ecology.

    Science.gov (United States)

    Milner-Gulland, E J; Shea, K

    2017-12-01

    Applied ecologists often face uncertainty that hinders effective decision-making.Common traps that may catch the unwary are: ignoring uncertainty, acknowledging uncertainty but ploughing on, focussing on trivial uncertainties, believing your models, and unclear objectives.We integrate research insights and examples from a wide range of applied ecological fields to illustrate advances that are generally underused, but could facilitate ecologists' ability to plan and execute research to support management.Recommended approaches to avoid uncertainty traps are: embracing models, using decision theory, using models more effectively, thinking experimentally, and being realistic about uncertainty. Synthesis and applications . Applied ecologists can become more effective at informing management by using approaches that explicitly take account of uncertainty.

  4. Oil price uncertainty in Canada

    Energy Technology Data Exchange (ETDEWEB)

    Elder, John [Department of Finance and Real Estate, 1272 Campus Delivery, Colorado State University, Fort Collins, CO 80523 (United States); Serletis, Apostolos [Department of Economics, University of Calgary, Calgary, Alberta (Canada)

    2009-11-15

    Bernanke [Bernanke, Ben S. Irreversibility, uncertainty, and cyclical investment. Quarterly Journal of Economics 98 (1983), 85-106.] shows how uncertainty about energy prices may induce optimizing firms to postpone investment decisions, thereby leading to a decline in aggregate output. Elder and Serletis [Elder, John and Serletis, Apostolos. Oil price uncertainty.] find empirical evidence that uncertainty about oil prices has tended to depress investment in the United States. In this paper we assess the robustness of these results by investigating the effects of oil price uncertainty in Canada. Our results are remarkably similar to existing results for the United States, providing additional evidence that uncertainty about oil prices may provide another explanation for why the sharp oil price declines of 1985 failed to produce rapid output growth. Impulse-response analysis suggests that uncertainty about oil prices may tend to reinforce the negative response of output to positive oil shocks. (author)

  5. Quantification of margins and uncertainties: Alternative representations of epistemic uncertainty

    International Nuclear Information System (INIS)

    Helton, Jon C.; Johnson, Jay D.

    2011-01-01

    In 2001, the National Nuclear Security Administration of the U.S. Department of Energy in conjunction with the national security laboratories (i.e., Los Alamos National Laboratory, Lawrence Livermore National Laboratory and Sandia National Laboratories) initiated development of a process designated Quantification of Margins and Uncertainties (QMU) for the use of risk assessment methodologies in the certification of the reliability and safety of the nation's nuclear weapons stockpile. A previous presentation, 'Quantification of Margins and Uncertainties: Conceptual and Computational Basis,' describes the basic ideas that underlie QMU and illustrates these ideas with two notional examples that employ probability for the representation of aleatory and epistemic uncertainty. The current presentation introduces and illustrates the use of interval analysis, possibility theory and evidence theory as alternatives to the use of probability theory for the representation of epistemic uncertainty in QMU-type analyses. The following topics are considered: the mathematical structure of alternative representations of uncertainty, alternative representations of epistemic uncertainty in QMU analyses involving only epistemic uncertainty, and alternative representations of epistemic uncertainty in QMU analyses involving a separation of aleatory and epistemic uncertainty. Analyses involving interval analysis, possibility theory and evidence theory are illustrated with the same two notional examples used in the presentation indicated above to illustrate the use of probability to represent aleatory and epistemic uncertainty in QMU analyses.

  6. Gender Gap in Returns to Schooling in Palestine

    Science.gov (United States)

    Daoud, Yousef

    2005-01-01

    This study provides estimates of the private returns to schooling in Palestine utilizing eight quarterly labor force surveys for 1999 and 2001. This period was chosen to investigate the differential impact of the Israeli closure policy on Palestinian male and female workers. Although gross enrollment ratios for males and females reveal little to…

  7. Virus isolation for diagnosing dengue virus infections in returning travelers

    NARCIS (Netherlands)

    Teichmann, D.; Göbels, K.; Niedrig, M.; Sim-Brandenburg, J.-W.; Làge-Stehr, J.; Grobusch, M. P.

    2003-01-01

    Dengue fever is recognized as one of the most frequent imported acute febrile illnesses affecting European tourists returning from the tropics. In order to assess the value of virus isolation for the diagnosis of dengue fever, 70 cases of dengue fever confirmed in German travelers during the period

  8. The Volatility Effect: Lower Risk without Lower Return

    NARCIS (Netherlands)

    D.C. Blitz (David); P. van Vliet (Pim)

    2007-01-01

    textabstractWe present empirical evidence that stocks with low volatility earn high risk-adjusted returns. The annual alpha spread of global low versus high volatility decile portfolios amounts to 12% over the 1986-2006 period. We also observe this volatility effect within the US, European and

  9. Hard assets : The return on rare diamonds and gems

    NARCIS (Netherlands)

    Renneboog, L.D.R.; Spaenjers, C.

    2012-01-01

    This note examines the investment performance of diamonds and other gems (sapphires, rubies, and emeralds) over the period 1999–2010, using a novel data set of auction transactions. Over our time frame, the annualized real USD returns for white and colored diamonds equaled 6.4% and 2.9%,

  10. Hard Assets : The Returns on Rare Diamonds and Gems

    NARCIS (Netherlands)

    Renneboog, L.D.R.; Spaenjers, C.

    2011-01-01

    This paper examines the investment performance of diamonds and other gems (sapphires, rubies, and emeralds) over the period 1999-2010, using a novel data set of auction transactions. Between 1999 and 2010, the annualized real USD returns for white and colored diamonds equaled 6.4% and 2.9%,

  11. Hard assets : The return of rare diamonds and gems

    NARCIS (Netherlands)

    Renneboog, Luc; Spaenjers, Christophe; Grynberg, Roman; Mbayi, Letsema

    This note examines the investment performance of diamonds and other gems (sapphires, rubies, and emeralds) over the period 1999–2010, using a novel data set of auction transactions. Over our time frame, the annualized real USD returns for white and colored diamonds equaled 6.4% and 2.9%,

  12. Uncertainty in a monthly water balance model using the generalized likelihood uncertainty estimation methodology

    Science.gov (United States)

    Rivera, Diego; Rivas, Yessica; Godoy, Alex

    2015-02-01

    Hydrological models are simplified representations of natural processes and subject to errors. Uncertainty bounds are a commonly used way to assess the impact of an input or model architecture uncertainty in model outputs. Different sets of parameters could have equally robust goodness-of-fit indicators, which is known as Equifinality. We assessed the outputs from a lumped conceptual hydrological model to an agricultural watershed in central Chile under strong interannual variability (coefficient of variability of 25%) by using the Equifinality concept and uncertainty bounds. The simulation period ran from January 1999 to December 2006. Equifinality and uncertainty bounds from GLUE methodology (Generalized Likelihood Uncertainty Estimation) were used to identify parameter sets as potential representations of the system. The aim of this paper is to exploit the use of uncertainty bounds to differentiate behavioural parameter sets in a simple hydrological model. Then, we analyze the presence of equifinality in order to improve the identification of relevant hydrological processes. The water balance model for Chillan River exhibits, at a first stage, equifinality. However, it was possible to narrow the range for the parameters and eventually identify a set of parameters representing the behaviour of the watershed (a behavioural model) in agreement with observational and soft data (calculation of areal precipitation over the watershed using an isohyetal map). The mean width of the uncertainty bound around the predicted runoff for the simulation period decreased from 50 to 20 m3s-1 after fixing the parameter controlling the areal precipitation over the watershed. This decrement is equivalent to decreasing the ratio between simulated and observed discharge from 5.2 to 2.5. Despite the criticisms against the GLUE methodology, such as the lack of statistical formality, it is identified as a useful tool assisting the modeller with the identification of critical parameters.

  13. THE INFLUENCE OF CORPORATE FINANCIAL PERFORMANCE ON SHARE RETURN

    Directory of Open Access Journals (Sweden)

    Ghulam Nurul Huda

    2015-09-01

    Full Text Available This study was conducted to examine the effect of financial performances of Economic Value Added (EVA, Market Value Added (MVA as well as financial ratios (Fixed Asset Turnover, Return on Investment, Debt to Equity Ratio, Price to Book Value, Total Asset Turnover on Stock Return. This study used the data of six representative palm oil companies which were listed in Indonesia Stock Exchange. The analysis models that were used included three multiple regression equations for EVA, MVA and Stock Return. The results indicate that DER significantly influences EVA and PBV, and TATO significantly influences MVA. Return Shares are significantly only affected by EVA. The company's fundamentals, especially EVA, PBV, TATO and DER were used by investors to predict the Stock Return in Indonesia Stock Exchange in 2009–2014 period. This study confirmed the previous studies that these variables are involved on regression model to predict the Stock Return. The results of the analysis of the company's financial performance with EVA and MVA and financial fundamental variables provide a better alternative picture on the achievement of the company so that the benefits in investing in the palm oil business in Indonesia can be maximally managed.Keywords: Indonesia Stock Exchange, investor, market, multiple regression, stock

  14. Investigating different factors influencing on return of private banks

    Directory of Open Access Journals (Sweden)

    Pegah Motamedi

    2013-09-01

    Full Text Available Return of Investment has always been an interesting area of research among academics as well as investors. Although capital asset pricing model (CAPM is capable of estimating risk of investment, many people argue that CAPM is not able to predict long-term return, properly. This paper presents an empirical investigation to find the effects of different financial figures including systematic risk (Beta, size of firm, ratio of book value to market share, volume of trade and the ratio of price/earnings (P/E on return of private banks in Iran. The study gathers the necessary information over the period 2005-2011 from private banks in Iran. The study uses multiple regression technique to find the effects of mentioned variables on return of private banks. The results indicate that there are some meaningful and positive relationship between return of banks and systematic risk (Beta, size, volume of trade and P/E. The study also finds some meaningful and reverse relationship between bank return and book value on market value.

  15. Return on Investment: A Placebo for the Chief Financial Officer... and Other Paradoxes

    Science.gov (United States)

    Andru, Peter; Botchkarev, Alexei

    2011-01-01

    Background: Return on investment (ROI) is one of the most popular evaluation metrics. ROI analysis (when applied correctly) is a powerful tool of evaluating existing information systems and making informed decisions on the acquisitions. However, practical use of the ROI is complicated by a number of uncertainties and controversies. The article…

  16. 26 CFR 301.6103(j)(5)-1 - Disclosures of return information reflected on returns to officers and employees of the...

    Science.gov (United States)

    2010-04-01

    ... Security Number; (iii) Annual accounting period; (iv) Principal Business Activity (PBA) code; (v) Taxable...” and Form 1065-B “U.S. Return of Income for Electing Large Partnerships” (Schedule F)— (i) Taxpayer...

  17. Financial Integration and Asset Returns

    OpenAIRE

    P Martin; H Rey

    2000-01-01

    The paper investigates the impact of financial integration on asset return, risk diversification and breadth of financial markets. We analyse a three-country macroeconomic model in which (i) the number of financial assets is endogenous; (ii) assets are imperfect substitutes; (iii) cross-border asset trade entails some transaction costs; (iv) the investment technology is indivisible. In such an environment, lower transaction costs between two financial markets translate to higher demand for as...

  18. Tick size and stock returns

    Science.gov (United States)

    Onnela, Jukka-Pekka; Töyli, Juuso; Kaski, Kimmo

    2009-02-01

    Tick size is an important aspect of the micro-structural level organization of financial markets. It is the smallest institutionally allowed price increment, has a direct bearing on the bid-ask spread, influences the strategy of trading order placement in electronic markets, affects the price formation mechanism, and appears to be related to the long-term memory of volatility clustering. In this paper we investigate the impact of tick size on stock returns. We start with a simple simulation to demonstrate how continuous returns become distorted after confining the price to a discrete grid governed by the tick size. We then move on to a novel experimental set-up that combines decimalization pilot programs and cross-listed stocks in New York and Toronto. This allows us to observe a set of stocks traded simultaneously under two different ticks while holding all security-specific characteristics fixed. We then study the normality of the return distributions and carry out fits to the chosen distribution models. Our empirical findings are somewhat mixed and in some cases appear to challenge the simulation results.

  19. Heisenberg's principle of uncertainty and the uncertainty relations

    International Nuclear Information System (INIS)

    Redei, Miklos

    1987-01-01

    The usual verbal form of the Heisenberg uncertainty principle and the usual mathematical formulation (the so-called uncertainty theorem) are not equivalent. The meaning of the concept 'uncertainty' is not unambiguous and different interpretations are used in the literature. Recently a renewed interest has appeared to reinterpret and reformulate the precise meaning of Heisenberg's principle and to find adequate mathematical form. The suggested new theorems are surveyed and critically analyzed. (D.Gy.) 20 refs

  20. Orientation and uncertainties

    International Nuclear Information System (INIS)

    Peters, H.P.; Hennen, L.

    1990-01-01

    The authors report on the results of three representative surveys that made a closer inquiry into perceptions and valuations of information and information sources concering Chernobyl. If turns out that the information sources are generally considered little trustworthy. This was generally attributable to the interpretation of the events being tied to attitudes in the atmonic energy issue. The greatest credit was given to television broadcasting. The authors summarize their discourse as follows: There is good reason to interpret the widespread uncertainty after Chernobyl as proof of the fact that large parts of the population are prepared and willing to assume a critical stance towards information and prefer to draw their information from various sources representing different positions. (orig.) [de

  1. DOD ELAP Lab Uncertainties

    Science.gov (United States)

    2012-03-01

    ISO / IEC   17025  Inspection Bodies – ISO / IEC  17020  RMPs – ISO  Guide 34 (Reference...certify to :  ISO  9001 (QMS),  ISO  14001 (EMS),   TS 16949 (US Automotive)  etc. 2 3 DoD QSM 4.2 standard   ISO / IEC   17025 :2005  Each has uncertainty...IPV6, NLLAP, NEFAP  TRAINING Programs  Certification Bodies – ISO / IEC  17021  Accreditation for  Management System 

  2. Traceability and Measurement Uncertainty

    DEFF Research Database (Denmark)

    Tosello, Guido; De Chiffre, Leonardo

    2004-01-01

    . The project partnership aims (composed by 7 partners in 5 countries, thus covering a real European spread in high tech production technology) to develop and implement an advanced e-learning system that integrates contributions from quite different disciplines into a user-centred approach that strictly....... Machine tool testing 9. The role of manufacturing metrology for QM 10. Inspection planning 11. Quality management of measurements incl. Documentation 12. Advanced manufacturing measurement technology The present report (which represents the section 2 - Traceability and Measurement Uncertainty – of the e-learning......This report is made as a part of the project ‘Metro-E-Learn: European e-Learning in Manufacturing Metrology’, an EU project under the program SOCRATES MINERVA (ODL and ICT in Education), Contract No: 101434-CP-1-2002-1-DE-MINERVA, coordinated by Friedrich-Alexander-University Erlangen...

  3. Decision making under uncertainty

    International Nuclear Information System (INIS)

    Cyert, R.M.

    1989-01-01

    This paper reports on ways of improving the reliability of products and systems in this country if we are to survive as a first-rate industrial power. The use of statistical techniques have, since the 1920s, been viewed as one of the methods for testing quality and estimating the level of quality in a universe of output. Statistical quality control is not relevant, generally, to improving systems in an industry like yours, but certainly the use of probability concepts is of significance. In addition, when it is recognized that part of the problem involves making decisions under uncertainty, it becomes clear that techniques such as sequential decision making and Bayesian analysis become major methodological approaches that must be utilized

  4. Sustainability and uncertainty

    DEFF Research Database (Denmark)

    Jensen, Karsten Klint

    2007-01-01

    The widely used concept of sustainability is seldom precisely defined, and its clarification involves making up one's mind about a range of difficult questions. One line of research (bottom-up) takes sustaining a system over time as its starting point and then infers prescriptions from...... this requirement. Another line (top-down) takes an economical interpretation of the Brundtland Commission's suggestion that the present generation's needsatisfaction should not compromise the need-satisfaction of future generations as its starting point. It then measures sustainability at the level of society...... a clarified ethical goal, disagreements can arise. At present we do not know what substitutions will be possible in the future. This uncertainty clearly affects the prescriptions that follow from the measure of sustainability. Consequently, decisions about how to make future agriculture sustainable...

  5. An uncertainty inventory demonstration - a primary step in uncertainty quantification

    Energy Technology Data Exchange (ETDEWEB)

    Langenbrunner, James R. [Los Alamos National Laboratory; Booker, Jane M [Los Alamos National Laboratory; Hemez, Francois M [Los Alamos National Laboratory; Salazar, Issac F [Los Alamos National Laboratory; Ross, Timothy J [UNM

    2009-01-01

    Tools, methods, and theories for assessing and quantifying uncertainties vary by application. Uncertainty quantification tasks have unique desiderata and circumstances. To realistically assess uncertainty requires the engineer/scientist to specify mathematical models, the physical phenomena of interest, and the theory or framework for assessments. For example, Probabilistic Risk Assessment (PRA) specifically identifies uncertainties using probability theory, and therefore, PRA's lack formal procedures for quantifying uncertainties that are not probabilistic. The Phenomena Identification and Ranking Technique (PIRT) proceeds by ranking phenomena using scoring criteria that results in linguistic descriptors, such as importance ranked with words, 'High/Medium/Low.' The use of words allows PIRT to be flexible, but the analysis may then be difficult to combine with other uncertainty theories. We propose that a necessary step for the development of a procedure or protocol for uncertainty quantification (UQ) is the application of an Uncertainty Inventory. An Uncertainty Inventory should be considered and performed in the earliest stages of UQ.

  6. Can Future Uncertainty Keep Children Out of School?

    DEFF Research Database (Denmark)

    Lilleør, Helene Bie

    that uncertainty about future returns results in a need for risk diversification, that children function as old-age security providers when there are no available pension systems, that the human capital investment decision of one child is likely to be influenced by that of his/her siblings, and that rural parents...... face a choice of investing in either specific or general human capital of their children. In this paper, I investigate the effects of future income uncertainty on the joint human capital investment decision of children in a household. I develop and calibrate a simple illustrative human capital...... portfolio model and show that existing levels of uncertainty can indeed result in less than full school enrolment within a household, even in a world of perfect credit markets. The paper thus offers an alternative explanation for why it might be optimal for rural parents not to send all of their children...

  7. Quantifying Stock Return Distributions in Financial Markets.

    Science.gov (United States)

    Botta, Federico; Moat, Helen Susannah; Stanley, H Eugene; Preis, Tobias

    2015-01-01

    Being able to quantify the probability of large price changes in stock markets is of crucial importance in understanding financial crises that affect the lives of people worldwide. Large changes in stock market prices can arise abruptly, within a matter of minutes, or develop across much longer time scales. Here, we analyze a dataset comprising the stocks forming the Dow Jones Industrial Average at a second by second resolution in the period from January 2008 to July 2010 in order to quantify the distribution of changes in market prices at a range of time scales. We find that the tails of the distributions of logarithmic price changes, or returns, exhibit power law decays for time scales ranging from 300 seconds to 3600 seconds. For larger time scales, we find that the distributions tails exhibit exponential decay. Our findings may inform the development of models of market behavior across varying time scales.

  8. Slow return of reason to nuclear regulation

    International Nuclear Information System (INIS)

    McGranery, J.P. Jr.

    1983-01-01

    During the 1970s, the promise of nuclear power as a cheap source of electricity was seriously eroded in practice. A variety of reasons, including governmental vacillation and delay, have been offered for those circumstances. With a different administration and an apparently improving national economy, it seems appropriate to look at some of the governmental developments of the last year to see if there is hope for the return of reasonable and predictable regulation to nuclear power. This article summarizes some of the principal actions by the courts, the regulatory agency, the administration, and the Congress during that period, as well as pending actions. It concludes that there is a favorable climate and reason to hope, but that success will depend, in the final analysis, upon the conduct of the industry itself. 73 references

  9. Essays on model uncertainty in financial models

    NARCIS (Netherlands)

    Li, Jing

    2018-01-01

    This dissertation studies model uncertainty, particularly in financial models. It consists of two empirical chapters and one theoretical chapter. The first empirical chapter (Chapter 2) classifies model uncertainty into parameter uncertainty and misspecification uncertainty. It investigates the

  10. Empirical Evidence on Student-t Log-Returns of Diversified World Stock Indices

    OpenAIRE

    Eckhard Platen; Renata Rendek

    2007-01-01

    The aim of this paper is to document some empirical facts related to log-returns of diversified world stock indices when these are denominated in different currencies. Motivated by earlier results, we have obtained the estimated distribution of log-returns for a range of world stock indices over long observation periods. We expand previous studies by applying the maximum likelihood ratio test to the large class of generalized hyperbolic distributions, and investigate the log-returns of a vari...

  11. A new uncertainty importance measure

    International Nuclear Information System (INIS)

    Borgonovo, E.

    2007-01-01

    Uncertainty in parameters is present in many risk assessment problems and leads to uncertainty in model predictions. In this work, we introduce a global sensitivity indicator which looks at the influence of input uncertainty on the entire output distribution without reference to a specific moment of the output (moment independence) and which can be defined also in the presence of correlations among the parameters. We discuss its mathematical properties and highlight the differences between the present indicator, variance-based uncertainty importance measures and a moment independent sensitivity indicator previously introduced in the literature. Numerical results are discussed with application to the probabilistic risk assessment model on which Iman [A matrix-based approach to uncertainty and sensitivity analysis for fault trees. Risk Anal 1987;7(1):22-33] first introduced uncertainty importance measures

  12. Uncertainty Management and Sensitivity Analysis

    DEFF Research Database (Denmark)

    Rosenbaum, Ralph K.; Georgiadis, Stylianos; Fantke, Peter

    2018-01-01

    Uncertainty is always there and LCA is no exception to that. The presence of uncertainties of different types and from numerous sources in LCA results is a fact, but managing them allows to quantify and improve the precision of a study and the robustness of its conclusions. LCA practice sometimes...... suffers from an imbalanced perception of uncertainties, justifying modelling choices and omissions. Identifying prevalent misconceptions around uncertainties in LCA is a central goal of this chapter, aiming to establish a positive approach focusing on the advantages of uncertainty management. The main...... objectives of this chapter are to learn how to deal with uncertainty in the context of LCA, how to quantify it, interpret and use it, and how to communicate it. The subject is approached more holistically than just focusing on relevant statistical methods or purely mathematical aspects. This chapter...

  13. Additivity of entropic uncertainty relations

    Directory of Open Access Journals (Sweden)

    René Schwonnek

    2018-03-01

    Full Text Available We consider the uncertainty between two pairs of local projective measurements performed on a multipartite system. We show that the optimal bound in any linear uncertainty relation, formulated in terms of the Shannon entropy, is additive. This directly implies, against naive intuition, that the minimal entropic uncertainty can always be realized by fully separable states. Hence, in contradiction to proposals by other authors, no entanglement witness can be constructed solely by comparing the attainable uncertainties of entangled and separable states. However, our result gives rise to a huge simplification for computing global uncertainty bounds as they now can be deduced from local ones. Furthermore, we provide the natural generalization of the Maassen and Uffink inequality for linear uncertainty relations with arbitrary positive coefficients.

  14. Estimating the returns to United Kingdom publicly funded musculoskeletal disease research in terms of net value of improved health outcomes.

    Science.gov (United States)

    Glover, Matthew; Montague, Erin; Pollitt, Alexandra; Guthrie, Susan; Hanney, Stephen; Buxton, Martin; Grant, Jonathan

    2018-01-10

    Building on an approach applied to cardiovascular and cancer research, we estimated the economic returns from United Kingdom public- and charitable-funded musculoskeletal disease (MSD) research that arise from the net value of the improved health outcomes in the United Kingdom. To calculate the economic returns from MSD-related research in the United Kingdom, we estimated (1) the public and charitable expenditure on MSD-related research in the United Kingdom between 1970 and 2013; (2) the net monetary benefit (NMB), derived from the health benefit in quality adjusted life years (QALYs) valued in monetary terms (using a base-case value of a QALY of £25,000) minus the cost of delivering that benefit, for a prioritised list of interventions from 1994 to 2013; (3) the proportion of NMB attributable to United Kingdom research; and (4) the elapsed time between research funding and health gain. The data collected from these four key elements were used to estimate the internal rate of return (IRR) from MSD-related research investments on health benefits. We analysed the uncertainties in the IRR estimate using a one-way sensitivity analysis. Expressed in 2013 prices, total expenditure on MSD-related research from 1970 to 2013 was £3.5 billion, and for the period used to estimate the rate of return, 1978-1997, was £1.4 billion. Over the period 1994-2013 the key interventions analysed produced 871,000 QALYs with a NMB of £16 billion, allowing for the net NHS costs resulting from them and valuing a QALY at £25,000. The proportion of benefit attributable to United Kingdom research was 30% and the elapsed time between funding and impact of MSD treatments was 16 years. Our best estimate of the IRR from MSD-related research was 7%, which is similar to the 9% for CVD and 10% for cancer research. Our estimate of the IRR from the net health gain to public and charitable funding of MSD-related research in the United Kingdom is substantial, and justifies the research investments

  15. Classifying Returns as Extreme: European Stock and Bond Markets

    DEFF Research Database (Denmark)

    Christiansen, Charlotte

    whereby a shorter sample period is needed. For the bond markets the simultaneous extreme return variable (used for analyzing integration and contagion of financial markets) is not statistically different for the two schemes. For the stock markets there are differences, but they are disappearing......I consider the stock and bond markets of 14 EU countries. I use two classification schemes for defining extreme returns: One, the existing univariate classification scheme which considers each market separately. Two, the new multivariate classification scheme that considers all the markets jointly...

  16. Decommissioning funding: ethics, implementation, uncertainties

    International Nuclear Information System (INIS)

    2006-01-01

    This status report on Decommissioning Funding: Ethics, Implementation, Uncertainties also draws on the experience of the NEA Working Party on Decommissioning and Dismantling (WPDD). The report offers, in a concise form, an overview of relevant considerations on decommissioning funding mechanisms with regard to ethics, implementation and uncertainties. Underlying ethical principles found in international agreements are identified, and factors influencing the accumulation and management of funds for decommissioning nuclear facilities are discussed together with the main sources of uncertainties of funding systems. (authors)

  17. Chemical model reduction under uncertainty

    KAUST Repository

    Najm, Habib; Galassi, R. Malpica; Valorani, M.

    2016-01-01

    We outline a strategy for chemical kinetic model reduction under uncertainty. We present highlights of our existing deterministic model reduction strategy, and describe the extension of the formulation to include parametric uncertainty in the detailed mechanism. We discuss the utility of this construction, as applied to hydrocarbon fuel-air kinetics, and the associated use of uncertainty-aware measures of error between predictions from detailed and simplified models.

  18. Chemical model reduction under uncertainty

    KAUST Repository

    Najm, Habib

    2016-01-05

    We outline a strategy for chemical kinetic model reduction under uncertainty. We present highlights of our existing deterministic model reduction strategy, and describe the extension of the formulation to include parametric uncertainty in the detailed mechanism. We discuss the utility of this construction, as applied to hydrocarbon fuel-air kinetics, and the associated use of uncertainty-aware measures of error between predictions from detailed and simplified models.

  19. The Uncertainty of Measurement Results

    Energy Technology Data Exchange (ETDEWEB)

    Ambrus, A. [Hungarian Food Safety Office, Budapest (Hungary)

    2009-07-15

    Factors affecting the uncertainty of measurement are explained, basic statistical formulae given, and the theoretical concept explained in the context of pesticide formulation analysis. Practical guidance is provided on how to determine individual uncertainty components within an analytical procedure. An extended and comprehensive table containing the relevant mathematical/statistical expressions elucidates the relevant underlying principles. Appendix I provides a practical elaborated example on measurement uncertainty estimation, above all utilizing experimental repeatability and reproducibility laboratory data. (author)

  20. Uncertainty analysis of environmental models

    International Nuclear Information System (INIS)

    Monte, L.

    1990-01-01

    In the present paper an evaluation of the output uncertainty of an environmental model for assessing the transfer of 137 Cs and 131 I in the human food chain are carried out on the basis of a statistical analysis of data reported by the literature. The uncertainty analysis offers the oppotunity of obtaining some remarkable information about the uncertainty of models predicting the migration of non radioactive substances in the environment mainly in relation to the dry and wet deposition

  1. Petroleum taxation under uncertainty - contingent claims

    International Nuclear Information System (INIS)

    Lund, D.

    1990-01-01

    A workable method for the analysis of incentive effects of petroleum taxes under uncertainty is presented. The main advantage of the method is that it concludes with a single number for the after-tax value of any development plan, and thus allows for a quantification of incentive effects for any given description of production possibilities. It is, however, not possible to describe tax effects under uncertainty by simple magnitudes independent of production possibilities, such as wedges in rates of return. The theoretical basis is the contingent claims analysis from finance theory, which is applicable in particular to companies that are owned by well-diversified shareholders. It is not obvious that the tax authorities of poorly diversified countries should value uncertain income streams by the same method. The Norwegian petroleum taxation is shown to have strongly distortionary effects compared to a no-tax situation or a cash flow tax. These distortions were reduced by the tax changes that followed the 1986 decreases in crude oil prices. A weakness of the model of the Norwegian system is that an exactly optimal financial policy for the company has not been found. 30 refs., 2 figs., 3 tabs

  2. Climate change adaptation accounting for huge uncertainties in future projections - the case of urban drainage

    Science.gov (United States)

    Willems, Patrick

    2015-04-01

    Hydrological design parameters, which are currently used in the guidelines for the design of urban drainage systems (Willems et al., 2013) have been revised, taking the Flanders region of Belgium as case study. The revision involved extrapolation of the design rainfall statistics, taking into account the current knowledge on future climate change trends till 2100. Uncertainties in these trend projections have been assessed after statistically analysing and downscaling by a quantile perturbation tool based on a broad ensemble set of climate model simulation results (44 regional + 69 global control-scenario climate model run combinations for different greenhouse gas scenarios). The impact results of the climate scenarios were investigated as changes to rainfall intensity-duration-frequency (IDF) curves. Thereafter, the climate scenarios and related changes in rainfall statistics were transferred to changes in flood frequencies of sewer systems and overflow frequencies of storage facilities. This has been done based on conceptual urban drainage models. Also the change in storage capacity required to exceed a given overflow return period, has been calculated for a range of return periods and infiltration or throughflow rates. These results were used on the basis of the revision of the hydraulic design rules of urban drainage systems. One of the major challenges while formulating these policy guidelines was the consideration of the huge uncertainties in the future climate change projections and impact assessments; see also the difficulties and pitfalls reported by the IWA/IAHR Joint Committee on Urban Drainage - Working group on urban rainfall (Willems et al., 2012). We made use of the risk concept, and found it a very useful approach to deal with the high uncertainties. It involves an impact study of the different climate projections, or - for practical reasons - a reduced set of climate scenarios tailored for the specific type of impact considered (urban floods in our

  3. Uncertainty quantification in resonance absorption

    International Nuclear Information System (INIS)

    Williams, M.M.R.

    2012-01-01

    We assess the uncertainty in the resonance escape probability due to uncertainty in the neutron and radiation line widths for the first 21 resonances in 232 Th as given by . Simulation, quadrature and polynomial chaos methods are used and the resonance data are assumed to obey a beta distribution. We find the uncertainty in the total resonance escape probability to be the equivalent, in reactivity, of 75–130 pcm. Also shown are pdfs of the resonance escape probability for each resonance and the variation of the uncertainty with temperature. The viability of the polynomial chaos expansion method is clearly demonstrated.

  4. Reliability analysis under epistemic uncertainty

    International Nuclear Information System (INIS)

    Nannapaneni, Saideep; Mahadevan, Sankaran

    2016-01-01

    This paper proposes a probabilistic framework to include both aleatory and epistemic uncertainty within model-based reliability estimation of engineering systems for individual limit states. Epistemic uncertainty is considered due to both data and model sources. Sparse point and/or interval data regarding the input random variables leads to uncertainty regarding their distribution types, distribution parameters, and correlations; this statistical uncertainty is included in the reliability analysis through a combination of likelihood-based representation, Bayesian hypothesis testing, and Bayesian model averaging techniques. Model errors, which include numerical solution errors and model form errors, are quantified through Gaussian process models and included in the reliability analysis. The probability integral transform is used to develop an auxiliary variable approach that facilitates a single-level representation of both aleatory and epistemic uncertainty. This strategy results in an efficient single-loop implementation of Monte Carlo simulation (MCS) and FORM/SORM techniques for reliability estimation under both aleatory and epistemic uncertainty. Two engineering examples are used to demonstrate the proposed methodology. - Highlights: • Epistemic uncertainty due to data and model included in reliability analysis. • A novel FORM-based approach proposed to include aleatory and epistemic uncertainty. • A single-loop Monte Carlo approach proposed to include both types of uncertainties. • Two engineering examples used for illustration.

  5. Simplified propagation of standard uncertainties

    International Nuclear Information System (INIS)

    Shull, A.H.

    1997-01-01

    An essential part of any measurement control program is adequate knowledge of the uncertainties of the measurement system standards. Only with an estimate of the standards'' uncertainties can one determine if the standard is adequate for its intended use or can one calculate the total uncertainty of the measurement process. Purchased standards usually have estimates of uncertainty on their certificates. However, when standards are prepared and characterized by a laboratory, variance propagation is required to estimate the uncertainty of the standard. Traditional variance propagation typically involves tedious use of partial derivatives, unfriendly software and the availability of statistical expertise. As a result, the uncertainty of prepared standards is often not determined or determined incorrectly. For situations meeting stated assumptions, easier shortcut methods of estimation are now available which eliminate the need for partial derivatives and require only a spreadsheet or calculator. A system of simplifying the calculations by dividing into subgroups of absolute and relative uncertainties is utilized. These methods also incorporate the International Standards Organization (ISO) concepts for combining systematic and random uncertainties as published in their Guide to the Expression of Measurement Uncertainty. Details of the simplified methods and examples of their use are included in the paper

  6. Evaluation of uncertainties in the calibration of radiation survey meter

    International Nuclear Information System (INIS)

    Potiens, M.P.A.; Santos, G.P.

    2006-01-01

    In order to meet the requirements of ISO 17025, the quantification of the expanded uncertainties of experimental data in the calibration of survey meters must be carried out using well defined concepts, like those expressed in the 'ISO-Guide to the Expression of Uncertainty in Measurement'. The calibration procedure of gamma ray survey meters involves two values that have to get their uncertainties clearly known: measurements of the instrument under calibration and the conventional true values of a quantity. Considering the continuous improvement of the calibration methods and set-ups, it is necessary to evaluate periodically the involved uncertainties in the procedures. In this work it is shown how the measurement uncertainties of an individual calibration can be estimated and how it can be generalized to be valid for others radiation survey meters. (authors)

  7. Climate Certainties and Uncertainties

    International Nuclear Information System (INIS)

    Morel, Pierre

    2012-01-01

    In issue 380 of Futuribles in December 2011, Antonin Pottier analysed in detail the workings of what is today termed 'climate scepticism' - namely the propensity of certain individuals to contest the reality of climate change on the basis of pseudo-scientific arguments. He emphasized particularly that what fuels the debate on climate change is, largely, the degree of uncertainty inherent in the consequences to be anticipated from observation of the facts, not the description of the facts itself. In his view, the main aim of climate sceptics is to block the political measures for combating climate change. However, since they do not admit to this political posture, they choose instead to deny the scientific reality. This month, Futuribles complements this socio-psychological analysis of climate-sceptical discourse with an - in this case, wholly scientific - analysis of what we know (or do not know) about climate change on our planet. Pierre Morel gives a detailed account of the state of our knowledge in the climate field and what we are able to predict in the medium/long-term. After reminding us of the influence of atmospheric meteorological processes on the climate, he specifies the extent of global warming observed since 1850 and the main origin of that warming, as revealed by the current state of knowledge: the increase in the concentration of greenhouse gases. He then describes the changes in meteorological regimes (showing also the limits of climate simulation models), the modifications of hydrological regimes, and also the prospects for rises in sea levels. He also specifies the mechanisms that may potentially amplify all these phenomena and the climate disasters that might ensue. Lastly, he shows what are the scientific data that cannot be disregarded, the consequences of which are now inescapable (melting of the ice-caps, rises in sea level etc.), the only remaining uncertainty in this connection being the date at which these things will happen. 'In this

  8. Returning to sports after a back injury

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000518.htm Returning to sports after a back injury To use the sharing ... Back pain - returning to sports Which Type of Sport is Best? In deciding when and if to ...

  9. Returns to Tenure or Seniority?

    DEFF Research Database (Denmark)

    Buhai, Ioan Sebastian; Portela, Miguel; Teulings, Coen

      This study documents two empirical regularities, using data for Denmark and Portugal. First, workers who are hired last, are the first to leave the firm (Last In, First Out; LIFO). Second, workers' wages rise with seniority (= a Worker's tenure relative to the tenure of her colleagues). We seek...... at the moment of separation). The LIFO rule provides a stronger bargaining position for senior workers, leading to a return to seniority in wages. Efficiency in hiring requires the workers' .bargaining power to be in line with their share in the cost of specific investment. Then, the LIFO rule is a way...

  10. Sketching Uncertainty into Simulations.

    Science.gov (United States)

    Ribicic, H; Waser, J; Gurbat, R; Sadransky, B; Groller, M E

    2012-12-01

    In a variety of application areas, the use of simulation steering in decision making is limited at best. Research focusing on this problem suggests that most user interfaces are too complex for the end user. Our goal is to let users create and investigate multiple, alternative scenarios without the need for special simulation expertise. To simplify the specification of parameters, we move from a traditional manipulation of numbers to a sketch-based input approach. Users steer both numeric parameters and parameters with a spatial correspondence by sketching a change onto the rendering. Special visualizations provide immediate visual feedback on how the sketches are transformed into boundary conditions of the simulation models. Since uncertainty with respect to many intertwined parameters plays an important role in planning, we also allow the user to intuitively setup complete value ranges, which are then automatically transformed into ensemble simulations. The interface and the underlying system were developed in collaboration with experts in the field of flood management. The real-world data they have provided has allowed us to construct scenarios used to evaluate the system. These were presented to a variety of flood response personnel, and their feedback is discussed in detail in the paper. The interface was found to be intuitive and relevant, although a certain amount of training might be necessary.

  11. Uncertainty vs. Information (Invited)

    Science.gov (United States)

    Nearing, Grey

    2017-04-01

    Information theory is the branch of logic that describes how rational epistemic states evolve in the presence of empirical data (Knuth, 2005), and any logic of science is incomplete without such a theory. Developing a formal philosophy of science that recognizes this fact results in essentially trivial solutions to several longstanding problems are generally considered intractable, including: • Alleviating the need for any likelihood function or error model. • Derivation of purely logical falsification criteria for hypothesis testing. • Specification of a general quantitative method for process-level model diagnostics. More generally, I make the following arguments: 1. Model evaluation should not proceed by quantifying and/or reducing error or uncertainty, and instead should be approached as a problem of ensuring that our models contain as much information as our experimental data. I propose that the latter is the only question a scientist actually has the ability to ask. 2. Instead of building geophysical models as solutions to differential equations that represent conservation laws, we should build models as maximum entropy distributions constrained by conservation symmetries. This will allow us to derive predictive probabilities directly from first principles. Knuth, K. H. (2005) 'Lattice duality: The origin of probability and entropy', Neurocomputing, 67, pp. 245-274.

  12. Pandemic influenza: certain uncertainties

    Science.gov (United States)

    Morens, David M.; Taubenberger, Jeffery K.

    2011-01-01

    SUMMARY For at least five centuries, major epidemics and pandemics of influenza have occurred unexpectedly and at irregular intervals. Despite the modern notion that pandemic influenza is a distinct phenomenon obeying such constant (if incompletely understood) rules such as dramatic genetic change, cyclicity, “wave” patterning, virus replacement, and predictable epidemic behavior, much evidence suggests the opposite. Although there is much that we know about pandemic influenza, there appears to be much more that we do not know. Pandemics arise as a result of various genetic mechanisms, have no predictable patterns of mortality among different age groups, and vary greatly in how and when they arise and recur. Some are followed by new pandemics, whereas others fade gradually or abruptly into long-term endemicity. Human influenza pandemics have been caused by viruses that evolved singly or in co-circulation with other pandemic virus descendants and often have involved significant transmission between, or establishment of, viral reservoirs within other animal hosts. In recent decades, pandemic influenza has continued to produce numerous unanticipated events that expose fundamental gaps in scientific knowledge. Influenza pandemics appear to be not a single phenomenon but a heterogeneous collection of viral evolutionary events whose similarities are overshadowed by important differences, the determinants of which remain poorly understood. These uncertainties make it difficult to predict influenza pandemics and, therefore, to adequately plan to prevent them. PMID:21706672

  13. Big data uncertainties.

    Science.gov (United States)

    Maugis, Pierre-André G

    2018-07-01

    Big data-the idea that an always-larger volume of information is being constantly recorded-suggests that new problems can now be subjected to scientific scrutiny. However, can classical statistical methods be used directly on big data? We analyze the problem by looking at two known pitfalls of big datasets. First, that they are biased, in the sense that they do not offer a complete view of the populations under consideration. Second, that they present a weak but pervasive level of dependence between all their components. In both cases we observe that the uncertainty of the conclusion obtained by statistical methods is increased when used on big data, either because of a systematic error (bias), or because of a larger degree of randomness (increased variance). We argue that the key challenge raised by big data is not only how to use big data to tackle new problems, but to develop tools and methods able to rigorously articulate the new risks therein. Copyright © 2016. Published by Elsevier Ltd.

  14. PIV uncertainty quantification by image matching

    International Nuclear Information System (INIS)

    Sciacchitano, Andrea; Scarano, Fulvio; Wieneke, Bernhard

    2013-01-01

    A novel method is presented to quantify the uncertainty of PIV data. The approach is a posteriori, i.e. the unknown actual error of the measured velocity field is estimated using the velocity field itself as input along with the original images. The principle of the method relies on the concept of super-resolution: the image pair is matched according to the cross-correlation analysis and the residual distance between matched particle image pairs (particle disparity vector) due to incomplete match between the two exposures is measured. The ensemble of disparity vectors within the interrogation window is analyzed statistically. The dispersion of the disparity vector returns the estimate of the random error, whereas the mean value of the disparity indicates the occurrence of a systematic error. The validity of the working principle is first demonstrated via Monte Carlo simulations. Two different interrogation algorithms are considered, namely the cross-correlation with discrete window offset and the multi-pass with window deformation. In the simulated recordings, the effects of particle image displacement, its gradient, out-of-plane motion, seeding density and particle image diameter are considered. In all cases good agreement is retrieved, indicating that the error estimator is able to follow the trend of the actual error with satisfactory precision. Experiments where time-resolved PIV data are available are used to prove the concept under realistic measurement conditions. In this case the ‘exact’ velocity field is unknown; however a high accuracy estimate is obtained with an advanced interrogation algorithm that exploits the redundant information of highly temporally oversampled data (pyramid correlation, Sciacchitano et al (2012 Exp. Fluids 53 1087–105)). The image-matching estimator returns the instantaneous distribution of the estimated velocity measurement error. The spatial distribution compares very well with that of the actual error with maxima in the

  15. Uncertainty enabled Sensor Observation Services

    Science.gov (United States)

    Cornford, Dan; Williams, Matthew; Bastin, Lucy

    2010-05-01

    Almost all observations of reality are contaminated with errors, which introduce uncertainties into the actual observation result. Such uncertainty is often held to be a data quality issue, and quantification of this uncertainty is essential for the principled exploitation of the observations. Many existing systems treat data quality in a relatively ad-hoc manner, however if the observation uncertainty is a reliable estimate of the error on the observation with respect to reality then knowledge of this uncertainty enables optimal exploitation of the observations in further processes, or decision making. We would argue that the most natural formalism for expressing uncertainty is Bayesian probability theory. In this work we show how the Open Geospatial Consortium Sensor Observation Service can be implemented to enable the support of explicit uncertainty about observations. We show how the UncertML candidate standard is used to provide a rich and flexible representation of uncertainty in this context. We illustrate this on a data set of user contributed weather data where the INTAMAP interpolation Web Processing Service is used to help estimate the uncertainty on the observations of unknown quality, using observations with known uncertainty properties. We then go on to discuss the implications of uncertainty for a range of existing Open Geospatial Consortium standards including SWE common and Observations and Measurements. We discuss the difficult decisions in the design of the UncertML schema and its relation and usage within existing standards and show various options. We conclude with some indications of the likely future directions for UncertML in the context of Open Geospatial Consortium services.

  16. US Implied Volatility as A predictor of International Returns

    Directory of Open Access Journals (Sweden)

    Mehmet F. Dicle

    2017-12-01

    Full Text Available This study provides evidence of the US implied volatility’s e ect on international equitymarkets’ returns. This evidence has two main implications: i investors may find that foreign equityreturns adjusting to US implied volatility may not provide true diversification benefits, and ii foreignequity returns may be predicted using US implied volatility. Our sample includes US volatility index(VIX and major equity indexes in twenty countries for the period between January, 2000 throughJuly, 2017. VIX leads eighteen of the international markets and Granger causes seventeen of themarkets after controlling for the S&P-500 index returns and the 2007/2008 US financial crisis. USinvestors looking to diversify US risk may find that international equities may not provide intendeddiversification benefits. Our evidence provides support for predictability of international equity returnsbased on US volatility.

  17. Common Factors in International Bond Returns

    NARCIS (Netherlands)

    Driessen, J.J.A.G.; Melenberg, B.; Nijman, T.E.

    2000-01-01

    In this paper we estimate and interpret the factors that jointly determine bond returns of different maturities in the US, Germany and Japan.We analyze both currency-hedged and unhedged bond returns.For currency-hedged bond returns, we find that five factors explain 96.5% of the variation of bond

  18. Foreign currency returns and systematic risks

    NARCIS (Netherlands)

    Galsband, V.; Nitschka, T.

    2015-01-01

    We apply an empirical approximation of the intertemporal capital asset pricing model (ICAPM) to show that cross-sectional dispersion in currency returns can be rationalized by differences in currency excess returns' sensitivities to the market return's cash-flow news component. This finding echoes

  19. Account of the uncertainty factor in forecasting nuclear power development

    International Nuclear Information System (INIS)

    Chernavskij, S.Ya.

    1979-01-01

    Minimization of total discounted costs for linear constraints is commonly used in forecasting nuclear energy growth. This approach is considered inadequate due to the uncertainty of exogenous variables of the model. A method of forecasting that takes into account the presence of uncertainty is elaborated. An example that demonstrates the expediency of the method and its advantage over the conventional approximation method used for taking uncertainty into account is given. In the framework of the example, the optimal strategy for nuclear energy growth over period of 500 years is determined

  20. Financial globalisation uncertainty/instability is good for financial development

    OpenAIRE

    Asongu, Simplice A.; Koomson, Isaac; Tchamyou, Vanessa S.

    2015-01-01

    Purpose – This study assesses the effect of time-dynamic financial globalisation uncertainty on financial development in 53 African countries for the period 2000-2011. Design/methodology/approach – Financial globalisation uncertainty is estimated as time-dynamic to capture business cycle disturbances while all dimensions identified by the Financial Development and Structure Database of the World Bank are employed, namely: financial depth (money supply and liquid liabilities), financial sy...

  1. A commentary on model uncertainty

    International Nuclear Information System (INIS)

    Apostolakis, G.

    1994-01-01

    A framework is proposed for the identification of model and parameter uncertainties in risk assessment models. Two cases are distinguished; in the first case, a set of mutually exclusive and exhaustive hypotheses (models) can be formulated, while, in the second, only one reference model is available. The relevance of this formulation to decision making and the communication of uncertainties is discussed

  2. Mama Software Features: Uncertainty Testing

    Energy Technology Data Exchange (ETDEWEB)

    Ruggiero, Christy E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Porter, Reid B. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-05-30

    This document reviews how the uncertainty in the calculations is being determined with test image data. The results of this testing give an ‘initial uncertainty’ number than can be used to estimate the ‘back end’ uncertainty in digital image quantification in images. Statisticians are refining these numbers as part of a UQ effort.

  3. The role of communication and support in return to work following cancer-related absence.

    Science.gov (United States)

    Yarker, J; Munir, F; Bains, M; Kalawsky, K; Haslam, C

    2010-10-01

    Many cancer survivors experience difficulties returning to work. However, there have been relatively few attempts to understand why problems with employer support and work adjustment occur. This paper aims to extend previous work in two ways: first, through exploring the way in which communication and support at work effect cancer survivors on their return to work and during the post-return period; and second, by drawing on a research sample working in the United Kingdom. In all, 26 cancer survivors took part in a semi-structured telephone interview. Interviews were transcribed and analysed using thematic analysis. The analysis revealed three key findings. First, the central role of communication and support from (and between) occupational health, line managers, and colleagues was highlighted. Second, two discrete processes or periods of return to work were identified: the experience of return to work during the initial period of return and the experiences of post-return to work. Third, during the post-return period, the importance of the delayed impact of cancer on the ability to work, the lack of follow-up and monitoring, and the wear-off effect of empathy and support were highlighted as contributing to return-to-work difficulties. This qualitative study highlights the importance of communication within the workplace with regard to the return-to-work process and the need to provide better support and guidance to cancer survivors, line managers and colleagues. Research is required in delineating how employers without occupational health or human resources support manage the return-to-work process. Copyright © 2009 John Wiley & Sons, Ltd.

  4. Uncertainty evaluation methods for waste package performance assessment

    International Nuclear Information System (INIS)

    Wu, Y.T.; Nair, P.K.; Journel, A.G.; Abramson, L.R.

    1991-01-01

    This report identifies and investigates methodologies to deal with uncertainties in assessing high-level nuclear waste package performance. Four uncertainty evaluation methods (probability-distribution approach, bounding approach, expert judgment, and sensitivity analysis) are suggested as the elements of a methodology that, without either diminishing or enhancing the input uncertainties, can evaluate performance uncertainty. Such a methodology can also help identify critical inputs as a guide to reducing uncertainty so as to provide reasonable assurance that the risk objectives are met. This report examines the current qualitative waste containment regulation and shows how, in conjunction with the identified uncertainty evaluation methodology, a framework for a quantitative probability-based rule can be developed that takes account of the uncertainties. Current US Nuclear Regulatory Commission (NRC) regulation requires that the waste packages provide ''substantially complete containment'' (SCC) during the containment period. The term ''SCC'' is ambiguous and subject to interpretation. This report, together with an accompanying report that describes the technical considerations that must be addressed to satisfy high-level waste containment requirements, provides a basis for a third report to develop recommendations for regulatory uncertainty reduction in the ''containment''requirement of 10 CFR Part 60. 25 refs., 3 figs., 2 tabs

  5. Return to work among breast cancer survivors: A literature review.

    Science.gov (United States)

    Sun, Yuanlu; Shigaki, Cheryl L; Armer, Jane M

    2017-03-01

    Breast cancer survivors in their employment years are likely to try to go back to work after the primary treatment. Because the literature on return to work among breast cancer survivors is limited, we have undertaken a review of the literature to summarize what is known, including identifying important contributing variables and outcomes. This knowledge may be used to develop hypotheses and potential interventions to support breast cancer survivors who wish to return to work. We searched the following databases: CINAHL, MEDLINE, SCOUP, and PUBMED, within a 10-year timeframe (2004 to 2014). The majority of reviewed articles (N = 25) focused on three outcomes: return-to-work period, work ability, and work performance. The most frequently studied independent variables were collapsed into the following groups: health and well-being, symptoms and functioning, work demands and work environment, individual characteristics, and societal and cultural factors. Gaps in the literature include evidence of effective interventions to support return to work among breast cancer survivors and research to better understand the roles of government and business-related policy. All the studies reported a reduced work engagement and work ability. Employment status and work performance is associated with a combination of individual factors, work environment, culture, and resources. Significant gaps are apparent in the literature addressing breast cancer survivorship and return to work. This is a complex problem and it will likely require interdisciplinary research teams to develop effective and feasible interventions for this population.

  6. EMPIRICAL DISTRIBUTION OF STOCK RETURNS OF SOUTHEAST EUROPEAN EMERGING MARKETS

    Directory of Open Access Journals (Sweden)

    Aleksandar Naumoski

    2017-06-01

    Full Text Available The assumption that equity returns follow the normal distribution, most commonly made in financial economics theory and applications, is strongly rejected by empirical evidence presented in this paper. As it was found in many other studies, we confirm that stock returns follow a leptokurtic distribution and skewness, which in most of the Southeast European (SEE markets is negative. This paper investigates further whether there is any distribution that may be considered an optimal fit for stock returns in the SEE region. Using daily, weekly and monthly data samples for a period of five years from ten Southeast European emerging countries, we applied the Anderson-Darling test of Goodness-of-fit. We strongly rejected the aforementioned assumption of normality for all considered data samples and found that the daily stock returns are best fitted by the Johnson SU distribution whereas for the weekly and monthly stock returns there was not one predominant, but many distributions that can be considered a best fit.

  7. Maternal perspectives on the return of genetic results: context matters.

    Science.gov (United States)

    Lakes, Kimberley D; Vaughan, Elaine; Lemke, Amy; Jones, Marissa; Wigal, Timothy; Baker, Dean; Swanson, James M; Burke, Wylie

    2013-01-01

    The objectives of this study were to study maternal preferences for the return of their child's genetic results and to describe the experiences, perceptions, attitudes, and values that are brought to bear when individuals from different racial and cultural backgrounds consider participating in genetic research. We recruited women with diverse sociodemographic profiles to participate in seven focus groups. Twenty-eight percent of participants self-identified as Hispanic; 49% as White, non-Hispanic; and 21% as Asian or Asian American. Focus groups were conducted in English or Spanish and were audio-recorded and transcribed verbatim. Transcripts were analyzed using qualitative thematic methods. Results indicated that preferences and decisions regarding the return of results may depend on both research and individual contextual factors. Participants understood the return of results as a complex issue, where individual and cultural differences in preferences are certain to arise. Another key finding was that participants desired an interpersonal, dynamic, flexible process that accommodated individual preferences and contextual differences for returning results. Our findings indicate a need to have well-developed systems for allowing participants to make and change over time their choices regarding the return of their child's genetic results. Copyright © 2012 Wiley Periodicals, Inc.

  8. A study on relationship between the return of value/growth portfolio and market return: Evidence from Tehran Stock Exchange

    Directory of Open Access Journals (Sweden)

    Monireh Mashhadi Ramezanali

    2014-07-01

    Full Text Available This study examines the relationship between the returns of two value and growth portfolios and the return of market on 15 selected firms on Tehran Stock Exchange over the period 2008-2011. The study divides the firms into two groups in terms of the ratios of price on earning as well as price on book value into two groups of value and growth portfolios. Using some regression analysis, the study has determined a positive and meaningful relationship between value portfolio and market return when the market is on the upside but this relationship is not meaningful during the bear session. The results indicate that during the bull sessions, value portfolios provide better investment opportunities than growth ones do.

  9. THE EFFECT OF MACROECONOMIC VARIABLES ON STOCK RETURNS ON DHAKA STOCK EXCHANGE

    Directory of Open Access Journals (Sweden)

    Muhammed Monjurul Quadir

    2012-01-01

    Full Text Available This article investigates the effects of macroeconomic variables of treasury bill interest rate and industrial production on stock returns on Dhaka Stock Exchange for the period between January 2000 and February 2007 on the basis of monthly time series data using Autoregressive Integrated Moving Average (ARIMA model. The paper has taken the overall market stock returns as an independent variable. It does not consider the stock returns of different companies separately. Though the ARIMA model finds a positive relationship between Treasury bill interest rate and industrial production with market stock returns but the coefficients have turned out to be statistically insignificant.

  10. Stock Returns and Risk: Evidence from Quantile

    Directory of Open Access Journals (Sweden)

    Thomas C. Chiang

    2012-12-01

    Full Text Available This paper employs weighted least squares to examine the risk-return relation by applying high-frequency data from four major stock indexes in the US market and finds some evidence in favor of a positive relation between the mean of the excess returns and expected risk. However, by using quantile regressions, we find that the risk-return relation moves from negative to positive as the returns’ quantile increases. A positive risk-return relation is valid only in the upper quantiles. The evidence also suggests that intraday skewness plays a dominant role in explaining the variations of excess returns.

  11. Uncertainty Propagation Analysis for the Monte Carlo Time-Dependent Simulations

    International Nuclear Information System (INIS)

    Shaukata, Nadeem; Shim, Hyung Jin

    2015-01-01

    In this paper, a conventional method to control the neutron population for super-critical systems is implemented. Instead of considering the cycles, the simulation is divided in time intervals. At the end of each time interval, neutron population control is applied on the banked neutrons. Randomly selected neutrons are discarded, until the size of neutron population matches the initial neutron histories at the beginning of time simulation. A time-dependent simulation mode has also been implemented in the development version of SERPENT 2 Monte Carlo code. In this mode, sequential population control mechanism has been proposed for modeling of prompt super-critical systems. A Monte Carlo method has been properly used in TART code for dynamic criticality calculations. For super-critical systems, the neutron population is allowed to grow over a period of time. The neutron population is uniformly combed to return it to the neutron population started with at the beginning of time boundary. In this study, conventional time-dependent Monte Carlo (TDMC) algorithm is implemented. There is an exponential growth of neutron population in estimation of neutron density tally for super-critical systems and the number of neutrons being tracked exceed the memory of the computer. In order to control this exponential growth at the end of each time boundary, a conventional time cut-off controlling population strategy is included in TDMC. A scale factor is introduced to tally the desired neutron density at the end of each time boundary. The main purpose of this paper is the quantification of uncertainty propagation in neutron densities at the end of each time boundary for super-critical systems. This uncertainty is caused by the uncertainty resulting from the introduction of scale factor. The effectiveness of TDMC is examined for one-group infinite homogeneous problem (the rod model) and two-group infinite homogeneous problem. The desired neutron density is tallied by the introduction of

  12. Uncertainty Propagation Analysis for the Monte Carlo Time-Dependent Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Shaukata, Nadeem; Shim, Hyung Jin [Seoul National University, Seoul (Korea, Republic of)

    2015-10-15

    In this paper, a conventional method to control the neutron population for super-critical systems is implemented. Instead of considering the cycles, the simulation is divided in time intervals. At the end of each time interval, neutron population control is applied on the banked neutrons. Randomly selected neutrons are discarded, until the size of neutron population matches the initial neutron histories at the beginning of time simulation. A time-dependent simulation mode has also been implemented in the development version of SERPENT 2 Monte Carlo code. In this mode, sequential population control mechanism has been proposed for modeling of prompt super-critical systems. A Monte Carlo method has been properly used in TART code for dynamic criticality calculations. For super-critical systems, the neutron population is allowed to grow over a period of time. The neutron population is uniformly combed to return it to the neutron population started with at the beginning of time boundary. In this study, conventional time-dependent Monte Carlo (TDMC) algorithm is implemented. There is an exponential growth of neutron population in estimation of neutron density tally for super-critical systems and the number of neutrons being tracked exceed the memory of the computer. In order to control this exponential growth at the end of each time boundary, a conventional time cut-off controlling population strategy is included in TDMC. A scale factor is introduced to tally the desired neutron density at the end of each time boundary. The main purpose of this paper is the quantification of uncertainty propagation in neutron densities at the end of each time boundary for super-critical systems. This uncertainty is caused by the uncertainty resulting from the introduction of scale factor. The effectiveness of TDMC is examined for one-group infinite homogeneous problem (the rod model) and two-group infinite homogeneous problem. The desired neutron density is tallied by the introduction of

  13. Uncertainty propagation through dynamic models of assemblies of mechanical structures

    International Nuclear Information System (INIS)

    Daouk, Sami

    2016-01-01

    When studying the behaviour of mechanical systems, mathematical models and structural parameters are usually considered deterministic. Return on experience shows however that these elements are uncertain in most cases, due to natural variability or lack of knowledge. Therefore, quantifying the quality and reliability of the numerical model of an industrial assembly remains a major question in low-frequency dynamics. The purpose of this thesis is to improve the vibratory design of bolted assemblies through setting up a dynamic connector model that takes account of different types and sources of uncertainty on stiffness parameters, in a simple, efficient and exploitable in industrial context. This work has been carried out in the framework of the SICODYN project, led by EDF R and D, that aims to characterise and quantify, numerically and experimentally, the uncertainties in the dynamic behaviour of bolted industrial assemblies. Comparative studies of several numerical methods of uncertainty propagation demonstrate the advantage of using the Lack-Of-Knowledge theory. An experimental characterisation of uncertainties in bolted structures is performed on a dynamic test rig and on an industrial assembly. The propagation of many small and large uncertainties through different dynamic models of mechanical assemblies leads to the assessment of the efficiency of the Lack-Of-Knowledge theory and its applicability in an industrial environment. (author)

  14. The Effects of Twitter Sentiment on Stock Price Returns.

    Science.gov (United States)

    Ranco, Gabriele; Aleksovski, Darko; Caldarelli, Guido; Grčar, Miha; Mozetič, Igor

    2015-01-01

    Social media are increasingly reflecting and influencing behavior of other complex systems. In this paper we investigate the relations between a well-known micro-blogging platform Twitter and financial markets. In particular, we consider, in a period of 15 months, the Twitter volume and sentiment about the 30 stock companies that form the Dow Jones Industrial Average (DJIA) index. We find a relatively low Pearson correlation and Granger causality between the corresponding time series over the entire time period. However, we find a significant dependence between the Twitter sentiment and abnormal returns during the peaks of Twitter volume. This is valid not only for the expected Twitter volume peaks (e.g., quarterly announcements), but also for peaks corresponding to less obvious events. We formalize the procedure by adapting the well-known "event study" from economics and finance to the analysis of Twitter data. The procedure allows to automatically identify events as Twitter volume peaks, to compute the prevailing sentiment (positive or negative) expressed in tweets at these peaks, and finally to apply the "event study" methodology to relate them to stock returns. We show that sentiment polarity of Twitter peaks implies the direction of cumulative abnormal returns. The amount of cumulative abnormal returns is relatively low (about 1-2%), but the dependence is statistically significant for several days after the events.

  15. 76 FR 22611 - Specified Tax Return Preparers Required To File Individual Income Tax Returns Using Magnetic...

    Science.gov (United States)

    2011-04-22

    ... Specified Tax Return Preparers Required To File Individual Income Tax Returns Using Magnetic Media... Register on Wednesday, March 30, 2011 (76 FR 17521) providing guidance to specified tax return preparers who prepare and file individual income tax returns using magnetic media pursuant to section 6011(e)(3...

  16. FINANCIAL RETURN ON ASSETS. THE IMPACT OF THE FINANCIAL RETURN ON ASSETS OVER THE COMPANY’S DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Constantin Căruntu

    2009-11-01

    Full Text Available The financial rate of return is a significant indicator for assessing the economic and financial performance of an enterprise for the internal diagnosis, as well as for the analysis required by the external partners. The financial return is a basic indicator which characterizes the business performances that is found directly under the trade policy (trade cost, efficiency of capital employed (economic profitability but also under the financial policy of the company. If the economic rate of return expresses a remuneration of the employed capital only in relation to operating activities, the financial rate of return quantifies a remuneration of the private capital trough all three types of activity: operational, financial and extraordinary. Starting from the consideration that the financial rate of return expresses the efficiency of equity or permanent capital use of the company we can state that it is of particular importance to the shareholders of the company, which considers according to it’s level whether their investments are justified and they will continue to support the business development through raising of fresh capital or abandonment for a limited period to one part of the dividends due. Managers, in turn, will be keen on maintaining an appropriate level of this rate, in order to retain their positions and to achieve the performance criteria of the company.

  17. Returns on investments in energy-saving technologies under energy price uncertainty in Dutch greenhouse horticulture

    NARCIS (Netherlands)

    Diederen, P.J.M.; Tongeren, van F.W.; Veen, van der H.B.

    2003-01-01

    Conventional net present value calculations evaluating the profitability of investments in energy-saving technologies in Dutch horticultural outlays predict a much higher rate of adoption of these technologies than is actually observed. This paper tries to explain this gap by applying a real options

  18. Exploring Best Practice Skills to Predict Uncertainties in Venture Capital Investment Decision-Making

    Science.gov (United States)

    Blum, David Arthur

    Algae biodiesel is the sole sustainable and abundant transportation fuel source that can replace petrol diesel use; however, high competition and economic uncertainties exist, influencing independent venture capital decision making. Technology, market, management, and government action uncertainties influence competition and economic uncertainties in the venture capital industry. The purpose of this qualitative case study was to identify the best practice skills at IVC firms to predict uncertainty between early and late funding stages. The basis of the study was real options theory, a framework used to evaluate and understand the economic and competition uncertainties inherent in natural resource investment and energy derived from plant-based oils. Data were collected from interviews of 24 venture capital partners based in the United States who invest in algae and other renewable energy solutions. Data were analyzed by coding and theme development interwoven with the conceptual framework. Eight themes emerged: (a) expected returns model, (b) due diligence, (c) invest in specific sectors, (d) reduced uncertainty-late stage, (e) coopetition, (f) portfolio firm relationships, (g) differentiation strategy, and (h) modeling uncertainty and best practice. The most noteworthy finding was that predicting uncertainty at the early stage was impractical; at the expansion and late funding stages, however, predicting uncertainty was possible. The implications of these findings will affect social change by providing independent venture capitalists with best practice skills to increase successful exits, lessen uncertainty, and encourage increased funding of renewable energy firms, contributing to cleaner and healthier communities throughout the United States..

  19. Exploring the Processes of Self-Development Encountered by Adult Returners to Higher Education: A Lifespan Psychology Perspective

    Science.gov (United States)

    Mercer, Jenny

    2010-01-01

    Evidence indicates that non-traditional adult returners describe returning to education as a period of self-development and growth. However, lifespan psychology perspectives also show that successful growth and change involves periods of conflict. This paper will explore both the nature of self-development and conflicts experienced by a sample of…

  20. Detecting periodicities with Gaussian processes

    Directory of Open Access Journals (Sweden)

    Nicolas Durrande

    2016-04-01

    Full Text Available We consider the problem of detecting and quantifying the periodic component of a function given noise-corrupted observations of a limited number of input/output tuples. Our approach is based on Gaussian process regression, which provides a flexible non-parametric framework for modelling periodic data. We introduce a novel decomposition of the covariance function as the sum of periodic and aperiodic kernels. This decomposition allows for the creation of sub-models which capture the periodic nature of the signal and its complement. To quantify the periodicity of the signal, we derive a periodicity ratio which reflects the uncertainty in the fitted sub-models. Although the method can be applied to many kernels, we give a special emphasis to the Matérn family, from the expression of the reproducing kernel Hilbert space inner product to the implementation of the associated periodic kernels in a Gaussian process toolkit. The proposed method is illustrated by considering the detection of periodically expressed genes in the arabidopsis genome.

  1. Uncertainties in Nuclear Proliferation Modeling

    International Nuclear Information System (INIS)

    Kim, Chul Min; Yim, Man-Sung; Park, Hyeon Seok

    2015-01-01

    There have been various efforts in the research community to understand the determinants of nuclear proliferation and develop quantitative tools to predict nuclear proliferation events. Such systematic approaches have shown the possibility to provide warning for the international community to prevent nuclear proliferation activities. However, there are still large debates for the robustness of the actual effect of determinants and projection results. Some studies have shown that several factors can cause uncertainties in previous quantitative nuclear proliferation modeling works. This paper analyzes the uncertainties in the past approaches and suggests future works in the view of proliferation history, analysis methods, and variable selection. The research community still lacks the knowledge for the source of uncertainty in current models. Fundamental problems in modeling will remain even other advanced modeling method is developed. Before starting to develop fancy model based on the time dependent proliferation determinants' hypothesis, using graph theory, etc., it is important to analyze the uncertainty of current model to solve the fundamental problems of nuclear proliferation modeling. The uncertainty from different proliferation history coding is small. Serious problems are from limited analysis methods and correlation among the variables. Problems in regression analysis and survival analysis cause huge uncertainties when using the same dataset, which decreases the robustness of the result. Inaccurate variables for nuclear proliferation also increase the uncertainty. To overcome these problems, further quantitative research should focus on analyzing the knowledge suggested on the qualitative nuclear proliferation studies

  2. Measurement uncertainty: Friend or foe?

    Science.gov (United States)

    Infusino, Ilenia; Panteghini, Mauro

    2018-02-02

    The definition and enforcement of a reference measurement system, based on the implementation of metrological traceability of patients' results to higher order reference methods and materials, together with a clinically acceptable level of measurement uncertainty, are fundamental requirements to produce accurate and equivalent laboratory results. The uncertainty associated with each step of the traceability chain should be governed to obtain a final combined uncertainty on clinical samples fulfilling the requested performance specifications. It is important that end-users (i.e., clinical laboratory) may know and verify how in vitro diagnostics (IVD) manufacturers have implemented the traceability of their calibrators and estimated the corresponding uncertainty. However, full information about traceability and combined uncertainty of calibrators is currently very difficult to obtain. Laboratory professionals should investigate the need to reduce the uncertainty of the higher order metrological references and/or to increase the precision of commercial measuring systems. Accordingly, the measurement uncertainty should not be considered a parameter to be calculated by clinical laboratories just to fulfil the accreditation standards, but it must become a key quality indicator to describe both the performance of an IVD measuring system and the laboratory itself. Copyright © 2018 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  3. Model uncertainty in safety assessment

    International Nuclear Information System (INIS)

    Pulkkinen, U.; Huovinen, T.

    1996-01-01

    The uncertainty analyses are an essential part of any risk assessment. Usually the uncertainties of reliability model parameter values are described by probability distributions and the uncertainty is propagated through the whole risk model. In addition to the parameter uncertainties, the assumptions behind the risk models may be based on insufficient experimental observations and the models themselves may not be exact descriptions of the phenomena under analysis. The description and quantification of this type of uncertainty, model uncertainty, is the topic of this report. The model uncertainty is characterized and some approaches to model and quantify it are discussed. The emphasis is on so called mixture models, which have been applied in PSAs. Some of the possible disadvantages of the mixture model are addressed. In addition to quantitative analyses, also qualitative analysis is discussed shortly. To illustrate the models, two simple case studies on failure intensity and human error modeling are described. In both examples, the analysis is based on simple mixture models, which are observed to apply in PSA analyses. (orig.) (36 refs., 6 figs., 2 tabs.)

  4. Model uncertainty in safety assessment

    Energy Technology Data Exchange (ETDEWEB)

    Pulkkinen, U; Huovinen, T [VTT Automation, Espoo (Finland). Industrial Automation

    1996-01-01

    The uncertainty analyses are an essential part of any risk assessment. Usually the uncertainties of reliability model parameter values are described by probability distributions and the uncertainty is propagated through the whole risk model. In addition to the parameter uncertainties, the assumptions behind the risk models may be based on insufficient experimental observations and the models themselves may not be exact descriptions of the phenomena under analysis. The description and quantification of this type of uncertainty, model uncertainty, is the topic of this report. The model uncertainty is characterized and some approaches to model and quantify it are discussed. The emphasis is on so called mixture models, which have been applied in PSAs. Some of the possible disadvantages of the mixture model are addressed. In addition to quantitative analyses, also qualitative analysis is discussed shortly. To illustrate the models, two simple case studies on failure intensity and human error modeling are described. In both examples, the analysis is based on simple mixture models, which are observed to apply in PSA analyses. (orig.) (36 refs., 6 figs., 2 tabs.).

  5. An Empirical Study of the Effect of Investor Sentiment on Returns of Different Industries

    Directory of Open Access Journals (Sweden)

    Chuangxia Huang

    2014-01-01

    Full Text Available Studies on investor sentiment are mostly focused on the stock market, but little attention has been paid to the effect of investor sentiment on the return of a specific industry. This paper constructs a proxy variable to examine the relationship between investor sentiment and the return of a specific industry, using the Principle Component Analysis, and finds that investor sentiment is positively correlated with the industry return of the current period and negatively correlated with that of one lag period; we classify investor sentiment as optimistic state and pessimistic state and find that optimistic investor sentiment has a positive effect on stock returns of most industries, while pessimistic investor sentiment has no effect on them; this paper further builds a two-state Markov regime switching model and finds that sentiment has different effect on different industries returns on different states of market.

  6. Regulatory uncertainty and the associated business risk for emerging technologies

    International Nuclear Information System (INIS)

    Hoerr, Robert A.

    2011-01-01

    An oversight system specifically concerned with nanomaterials should be flexible enough to take into account the unique aspects of individual novel materials and the settings in which they might be used, while recognizing that heretofore unrecognized safety issues may require future modifications. This article considers a question not explicitly considered by the project team: what is the risk that uncertainty over how regulatory oversight will be applied to nanomaterials will delay or block the development of this emerging technology, thereby depriving human health of potential and substantial benefits? An ambiguous regulatory environment could delay the availability of valuable new technology and therapeutics for human health by reducing access to investment capital. Venture capitalists list regulatory uncertainty as a major reason not to invest at all in certain areas. Uncertainty is far more difficult to evaluate than risk, which lends itself to quantitative models and can be factored into projections of return on possible investments. Loss of time has a large impact on investment return. An examination of regulatory case histories suggests that an increase in regulatory resting requirement, where the path is well-defined, is far less costly than a delay of a year or more in achieving product approval and market launch.

  7. Regulatory uncertainty and the associated business risk for emerging technologies

    Science.gov (United States)

    Hoerr, Robert A.

    2011-04-01

    An oversight system specifically concerned with nanomaterials should be flexible enough to take into account the unique aspects of individual novel materials and the settings in which they might be used, while recognizing that heretofore unrecognized safety issues may require future modifications. This article considers a question not explicitly considered by the project team: what is the risk that uncertainty over how regulatory oversight will be applied to nanomaterials will delay or block the development of this emerging technology, thereby depriving human health of potential and substantial benefits? An ambiguous regulatory environment could delay the availability of valuable new technology and therapeutics for human health by reducing access to investment capital. Venture capitalists list regulatory uncertainty as a major reason not to invest at all in certain areas. Uncertainty is far more difficult to evaluate than risk, which lends itself to quantitative models and can be factored into projections of return on possible investments. Loss of time has a large impact on investment return. An examination of regulatory case histories suggests that an increase in regulatory resting requirement, where the path is well-defined, is far less costly than a delay of a year or more in achieving product approval and market launch.

  8. Model uncertainty: Probabilities for models?

    International Nuclear Information System (INIS)

    Winkler, R.L.

    1994-01-01

    Like any other type of uncertainty, model uncertainty should be treated in terms of probabilities. The question is how to do this. The most commonly-used approach has a drawback related to the interpretation of the probabilities assigned to the models. If we step back and look at the big picture, asking what the appropriate focus of the model uncertainty question should be in the context of risk and decision analysis, we see that a different probabilistic approach makes more sense, although it raise some implementation questions. Current work that is underway to address these questions looks very promising

  9. Decision-making under great uncertainty

    International Nuclear Information System (INIS)

    Hansson, S.O.

    1992-01-01

    Five types of decision-uncertainty are distinguished: uncertainty of consequences, of values, of demarcation, of reliance, and of co-ordination. Strategies are proposed for each type of uncertainty. The general conclusion is that it is meaningful for decision theory to treat cases with greater uncertainty than the textbook case of 'decision-making under uncertainty'. (au)

  10. Uncertainties in container failure time predictions

    International Nuclear Information System (INIS)

    Williford, R.E.

    1990-01-01

    Stochastic variations in the local chemical environment of a geologic waste repository can cause corresponding variations in container corrosion rates and failure times, and thus in radionuclide release rates. This paper addresses how well the future variations in repository chemistries must be known in order to predict container failure times that are bounded by a finite time period within the repository lifetime. Preliminary results indicate that a 5000 year scatter in predicted container failure times requires that repository chemistries be known to within ±10% over the repository lifetime. These are small uncertainties compared to current estimates. 9 refs., 3 figs

  11. A spatial and seasonal description of return-levels for the Berlin-Brandenburg region (Germany)

    Science.gov (United States)

    Fischer, Madlen; Rust, Henning W.; Ulbrich, Uwe

    2016-04-01

    Extreme precipitation events have a strong impact on the environment, society and economy. Besides the direct effect, e.g. damage due to hail, extreme precipitation can cause flood events, mudslides and increased erosion, which in turn lead to serious damage. Typically, return levels derived from annual maxima of daily precipitation sums are used for the design of hydraulic structures or for risk assessment in insurance companies. Seasonally or monthly resolved return levels are rarely considered, although they provide additional information: the higher temporal resolution can be beneficial for risk management, e.g. for agriculture or tourism sector. In addition, annual return levels derived from monthly maxima offer lower uncertainties, since a larger data basis are used for estimation. Here, the generalized extreme value distribution (GEV) is used to calculate monthly resolved return levels for 323 stations in the region Berlin-Brandenburg (Germany). Instead of estimating the parameters of the GEV for each month separately, the seasonal variation is captured by harmonic functions. This natural approach is particularly suitable for an efficient characterization of the seasonal variation of extreme precipitation. In a first step, a statistical model is developed for each station separately to estimate the monthly return levels. Besides the seasonal smoothness, also smoothness in space is exploited here. We use functions of longitude, latitude and altitude to describe the spatial variation of GEV parameters in the second step. Thus, uncertainty is reduced at gauges with short time series and estimates for ungauged sites can be obtained in a meaningful way.

  12. ASYMMETRY OF MARKET RETURNS AND THE MEAN VARIANCE FRONTIER

    OpenAIRE

    SENGUPTA, Jati K.; PARK, Hyung S.

    1994-01-01

    The hypothesis that the skewness and asymmetry have no significant impact on the mean variance frontier is found to be strongly violated by monthly U.S. data over the period January 1965 through December 1974. This result raises serious doubts whether the common market portifolios such as SP 500, value weighted and equal weighted returns can serve as suitable proxies for meanvariance efficient portfolios in the CAPM framework. A new test for assessing the impact of skewness on the variance fr...

  13. The Impact of Fund Attrition on Superannuation Returns

    OpenAIRE

    Drew, Michael E.; Stanford, Jon D.

    2001-01-01

    This paper investigates the impact of fund attrition on returns from a sample of superannuation fund managers (specialising in the management of domestic stock portfolios) for the period 1991 through 1999, using a four-factor asset pricing model. Survivorship bias is estimated at 23 basis points per annum. The evidence presented in this study is consistent with recent international evidence that suggests that a sampling technique that excludes terminated funds would result in an overestimatio...

  14. Return voltage: reproductibility of lack in isolated plastics

    International Nuclear Information System (INIS)

    Frutos, F.; Acedo, M.; Jimenez, A.; Perez, J.A.

    1998-01-01

    Return voltage measures from plane-plane and point-plane experimental test objects of polyethylene are presented. Even though a lack of reproducibility is observed, all the experimental voltage curves can be modellized as the sum of two exponential functions: a first one with a long time period and a second one with a quite shorter time parameter. This analytical behaviour could be theoretically explained by considering an exponential dielectric function response. (Author) 7 refs

  15. Unemployment, Investment and Global Expected Returns: A Panel FAVAR Approach

    OpenAIRE

    Ron Smith; Gylfi Zoega

    2005-01-01

    We consider the hypothesis that a common factor, global expected returns, drives unemployment and investment in 21 OECD countries over the period 1960-2002. We investigate this hypothesis using a panel-factor augmented-vector autoregression (FAVAR). We first estimate the common factors of unemployment and investment by principal components and show that the first principal component of unemployment is almost identical to that of investment and that they both show the pattern one would expect ...

  16. VARIABILITAS RETURN SAHAM DI SEKITAR PENGUMUMAN PERGANTIAN CHIEF EXECUTIVE OFFICER

    OpenAIRE

    Setiawan, Doddy

    2015-01-01

    The research aims at examining market reaction to CEO turnover announcements.The samples of the research consist of 59 CEO turnover announcements during 1992-2003periods. The author use security returns variance to examine information content of CEOturnover announcement. Friedman and Singh (1989) argue that contextual factorsmoderating the market reaction to the CEO turnover announcements. Therefore the authorconsidering two factors: the succession process and the origin of incoming CEO. The ...

  17. Variabilitas Return Saham di Sekitar Pengumuman Pergantian Chief Executive Officer

    OpenAIRE

    Setiawan, Doddy

    2007-01-01

    The research aims at examining market reaction to CEO turnover announcements.The samples of the research consist of 59 CEO turnover announcements during 1992-2003periods. The author use security returns variance to examine information content of CEOturnover announcement. Friedman and Singh (1989) argue that contextual factorsmoderating the market reaction to the CEO turnover announcements. Therefore the authorconsidering two factors: the succession process and the origin of incoming CEO. The ...

  18. Working Capital Approaches and Firm’s Returns in Pakistan

    OpenAIRE

    Dr. Talat Afza; Mian Sajid Nazir

    2008-01-01

    This study investigates the relationship between the aggressive/conservative working capital policies for seventeen industrial groups of public limited companies listed at Karachi Stock Exchange for a period of 1998-2003. The ordinary least square regression model has been used to investigate into the relationship of working capital approaches and the returns of firms. The study found significant differences among their working capital investment and financing policies across different indust...

  19. The Uncertainties of Risk Management

    DEFF Research Database (Denmark)

    Vinnari, Eija; Skærbæk, Peter

    2014-01-01

    for expanding risk management. More generally, such uncertainties relate to the professional identities and responsibilities of operational managers as defined by the framing devices. Originality/value – The paper offers three contributions to the extant literature: first, it shows how risk management itself......Purpose – The purpose of this paper is to analyse the implementation of risk management as a tool for internal audit activities, focusing on unexpected effects or uncertainties generated during its application. Design/methodology/approach – Public and confidential documents as well as semi......-structured interviews are analysed through the lens of actor-network theory to identify the effects of risk management devices in a Finnish municipality. Findings – The authors found that risk management, rather than reducing uncertainty, itself created unexpected uncertainties that would otherwise not have emerged...

  20. Climate Projections and Uncertainty Communication.

    Science.gov (United States)

    Joslyn, Susan L; LeClerc, Jared E

    2016-01-01

    Lingering skepticism about climate change might be due in part to the way climate projections are perceived by members of the public. Variability between scientists' estimates might give the impression that scientists disagree about the fact of climate change rather than about details concerning the extent or timing. Providing uncertainty estimates might clarify that the variability is due in part to quantifiable uncertainty inherent in the prediction process, thereby increasing people's trust in climate projections. This hypothesis was tested in two experiments. Results suggest that including uncertainty estimates along with climate projections leads to an increase in participants' trust in the information. Analyses explored the roles of time, place, demographic differences (e.g., age, gender, education level, political party affiliation), and initial belief in climate change. Implications are discussed in terms of the potential benefit of adding uncertainty estimates to public climate projections. Copyright © 2015 Cognitive Science Society, Inc.

  1. Relational uncertainty in service dyads

    DEFF Research Database (Denmark)

    Kreye, Melanie

    2017-01-01

    in service dyads and how they resolve it through suitable organisational responses to increase the level of service quality. Design/methodology/approach: We apply the overall logic of Organisational Information-Processing Theory (OIPT) and present empirical insights from two industrial case studies collected...... the relational uncertainty increased the functional quality while resolving the partner’s organisational uncertainty increased the technical quality of the delivered service. Originality: We make two contributions. First, we introduce relational uncertainty to the OM literature as the inability to predict...... and explain the actions of a partnering organisation due to a lack of knowledge about their abilities and intentions. Second, we present suitable organisational responses to relational uncertainty and their effect on service quality....

  2. Advanced LOCA code uncertainty assessment

    International Nuclear Information System (INIS)

    Wickett, A.J.; Neill, A.P.

    1990-11-01

    This report describes a pilot study that identified, quantified and combined uncertainties for the LOBI BL-02 3% small break test. A ''dials'' version of TRAC-PF1/MOD1, called TRAC-F, was used. (author)

  3. Risk of portfolio with simulated returns based on copula model

    Science.gov (United States)

    Razak, Ruzanna Ab; Ismail, Noriszura

    2015-02-01

    The commonly used tool for measuring risk of a portfolio with equally weighted stocks is variance-covariance method. Under extreme circumstances, this method leads to significant underestimation of actual risk due to its multivariate normality assumption of the joint distribution of stocks. The purpose of this research is to compare the actual risk of portfolio with the simulated risk of portfolio in which the joint distribution of two return series is predetermined. The data used is daily stock prices from the ASEAN market for the period January 2000 to December 2012. The copula approach is applied to capture the time varying dependence among the return series. The results shows that the chosen copula families are not suitable to present the dependence structures of each bivariate returns. Exception for the Philippines-Thailand pair where by t copula distribution appears to be the appropriate choice to depict its dependence. Assuming that the t copula distribution is the joint distribution of each paired series, simulated returns is generated and value-at-risk (VaR) is then applied to evaluate the risk of each portfolio consisting of two simulated return series. The VaR estimates was found to be symmetrical due to the simulation of returns via elliptical copula-GARCH approach. By comparison, it is found that the actual risks are underestimated for all pairs of portfolios except for Philippines-Thailand. This study was able to show that disregard of the non-normal dependence structure of two series will result underestimation of actual risk of the portfolio.

  4. How to live with uncertainties?

    International Nuclear Information System (INIS)

    Michel, R.

    2012-01-01

    In a short introduction, the problem of uncertainty as a general consequence of incomplete information as well as the approach to quantify uncertainty in metrology are addressed. A little history of the more than 30 years of the working group AK SIGMA is followed by an appraisal of its up-to-now achievements. Then, the potential future of the AK SIGMA is discussed based on its actual tasks and on open scientific questions and future topics. (orig.)

  5. Some remarks on modeling uncertainties

    International Nuclear Information System (INIS)

    Ronen, Y.

    1983-01-01

    Several topics related to the question of modeling uncertainties are considered. The first topic is related to the use of the generalized bias operator method for modeling uncertainties. The method is expanded to a more general form of operators. The generalized bias operator is also used in the inverse problem and applied to determine the anisotropic scattering law. The last topic discussed is related to the question of the limit to accuracy and how to establish its value. (orig.) [de

  6. Propagation of dynamic measurement uncertainty

    International Nuclear Information System (INIS)

    Hessling, J P

    2011-01-01

    The time-dependent measurement uncertainty has been evaluated in a number of recent publications, starting from a known uncertain dynamic model. This could be defined as the 'downward' propagation of uncertainty from the model to the targeted measurement. The propagation of uncertainty 'upward' from the calibration experiment to a dynamic model traditionally belongs to system identification. The use of different representations (time, frequency, etc) is ubiquitous in dynamic measurement analyses. An expression of uncertainty in dynamic measurements is formulated for the first time in this paper independent of representation, joining upward as well as downward propagation. For applications in metrology, the high quality of the characterization may be prohibitive for any reasonably large and robust model to pass the whiteness test. This test is therefore relaxed by not directly requiring small systematic model errors in comparison to the randomness of the characterization. Instead, the systematic error of the dynamic model is propagated to the uncertainty of the measurand, analogously but differently to how stochastic contributions are propagated. The pass criterion of the model is thereby transferred from the identification to acceptance of the total accumulated uncertainty of the measurand. This increases the relevance of the test of the model as it relates to its final use rather than the quality of the calibration. The propagation of uncertainty hence includes the propagation of systematic model errors. For illustration, the 'upward' propagation of uncertainty is applied to determine if an appliance box is damaged in an earthquake experiment. In this case, relaxation of the whiteness test was required to reach a conclusive result

  7. Optimal Taxation under Income Uncertainty

    OpenAIRE

    Xianhua Dai

    2011-01-01

    Optimal taxation under income uncertainty has been extensively developed in expected utility theory, but it is still open for inseparable utility function between income and effort. As an alternative of decision-making under uncertainty, prospect theory (Kahneman and Tversky (1979), Tversky and Kahneman (1992)) has been obtained empirical support, for example, Kahneman and Tversky (1979), and Camerer and Lowenstein (2003). It is beginning to explore optimal taxation in the context of prospect...

  8. New Perspectives on Policy Uncertainty

    OpenAIRE

    Hlatshwayo, Sandile

    2017-01-01

    In recent years, the ubiquitous and intensifying nature of economic policy uncertainty has made it a popular explanation for weak economic performance in developed and developing markets alike. The primary channel for this effect is decreased and delayed investment as firms adopt a ``wait and see'' approach to irreversible investments (Bernanke, 1983; Dixit and Pindyck, 1994). Deep empirical examination of policy uncertainty's impact is rare because of the difficulty associated in measuring i...

  9. Large contribution of natural aerosols to uncertainty in indirect forcing

    Science.gov (United States)

    Carslaw, K. S.; Lee, L. A.; Reddington, C. L.; Pringle, K. J.; Rap, A.; Forster, P. M.; Mann, G. W.; Spracklen, D. V.; Woodhouse, M. T.; Regayre, L. A.; Pierce, J. R.

    2013-11-01

    The effect of anthropogenic aerosols on cloud droplet concentrations and radiative properties is the source of one of the largest uncertainties in the radiative forcing of climate over the industrial period. This uncertainty affects our ability to estimate how sensitive the climate is to greenhouse gas emissions. Here we perform a sensitivity analysis on a global model to quantify the uncertainty in cloud radiative forcing over the industrial period caused by uncertainties in aerosol emissions and processes. Our results show that 45 per cent of the variance of aerosol forcing since about 1750 arises from uncertainties in natural emissions of volcanic sulphur dioxide, marine dimethylsulphide, biogenic volatile organic carbon, biomass burning and sea spray. Only 34 per cent of the variance is associated with anthropogenic emissions. The results point to the importance of understanding pristine pre-industrial-like environments, with natural aerosols only, and suggest that improved measurements and evaluation of simulated aerosols in polluted present-day conditions will not necessarily result in commensurate reductions in the uncertainty of forcing estimates.

  10. Large contribution of natural aerosols to uncertainty in indirect forcing.

    Science.gov (United States)

    Carslaw, K S; Lee, L A; Reddington, C L; Pringle, K J; Rap, A; Forster, P M; Mann, G W; Spracklen, D V; Woodhouse, M T; Regayre, L A; Pierce, J R

    2013-11-07

    The effect of anthropogenic aerosols on cloud droplet concentrations and radiative properties is the source of one of the largest uncertainties in the radiative forcing of climate over the industrial period. This uncertainty affects our ability to estimate how sensitive the climate is to greenhouse gas emissions. Here we perform a sensitivity analysis on a global model to quantify the uncertainty in cloud radiative forcing over the industrial period caused by uncertainties in aerosol emissions and processes. Our results show that 45 per cent of the variance of aerosol forcing since about 1750 arises from uncertainties in natural emissions of volcanic sulphur dioxide, marine dimethylsulphide, biogenic volatile organic carbon, biomass burning and sea spray. Only 34 per cent of the variance is associated with anthropogenic emissions. The results point to the importance of understanding pristine pre-industrial-like environments, with natural aerosols only, and suggest that improved measurements and evaluation of simulated aerosols in polluted present-day conditions will not necessarily result in commensurate reductions in the uncertainty of forcing estimates.

  11. Quantifying uncertainties in precipitation: a case study from Greece

    Directory of Open Access Journals (Sweden)

    C. Anagnostopoulou

    2008-04-01

    Full Text Available The main objective of the present study was the examination and the quantification of the uncertainties in the precipitation time series over the Greek area, for a 42-year time period. The uncertainty index applied to the rainfall data is a combination (total of the departures of the rainfall season length, of the median data of the accumulated percentages and of the total amounts of rainfall. Results of the study indicated that all the stations are characterized, on an average basis, by medium to high uncertainty. The stations that presented an increasing rainfall uncertainty were the ones located mainly to the continental parts of the study region. From the temporal analysis of the uncertainty index, it was demonstrated that the greatest percentage of the years, for all the stations time-series, was characterized by low to high uncertainty (intermediate categories of the index. Most of the results of the uncertainty index for the Greek region are similar to the corresponding results of various stations all over the European region.

  12. Pharmacological Fingerprints of Contextual Uncertainty.

    Directory of Open Access Journals (Sweden)

    Louise Marshall

    2016-11-01

    Full Text Available Successful interaction with the environment requires flexible updating of our beliefs about the world. By estimating the likelihood of future events, it is possible to prepare appropriate actions in advance and execute fast, accurate motor responses. According to theoretical proposals, agents track the variability arising from changing environments by computing various forms of uncertainty. Several neuromodulators have been linked to uncertainty signalling, but comprehensive empirical characterisation of their relative contributions to perceptual belief updating, and to the selection of motor responses, is lacking. Here we assess the roles of noradrenaline, acetylcholine, and dopamine within a single, unified computational framework of uncertainty. Using pharmacological interventions in a sample of 128 healthy human volunteers and a hierarchical Bayesian learning model, we characterise the influences of noradrenergic, cholinergic, and dopaminergic receptor antagonism on individual computations of uncertainty during a probabilistic serial reaction time task. We propose that noradrenaline influences learning of uncertain events arising from unexpected changes in the environment. In contrast, acetylcholine balances attribution of uncertainty to chance fluctuations within an environmental context, defined by a stable set of probabilistic associations, or to gross environmental violations following a contextual switch. Dopamine supports the use of uncertainty representations to engender fast, adaptive responses.

  13. A Bayesian approach to model uncertainty

    International Nuclear Information System (INIS)

    Buslik, A.

    1994-01-01

    A Bayesian approach to model uncertainty is taken. For the case of a finite number of alternative models, the model uncertainty is equivalent to parameter uncertainty. A derivation based on Savage's partition problem is given

  14. The NASA Langley Multidisciplinary Uncertainty Quantification Challenge

    Science.gov (United States)

    Crespo, Luis G.; Kenny, Sean P.; Giesy, Daniel P.

    2014-01-01

    This paper presents the formulation of an uncertainty quantification challenge problem consisting of five subproblems. These problems focus on key aspects of uncertainty characterization, sensitivity analysis, uncertainty propagation, extreme-case analysis, and robust design.

  15. Return to cyclical activity in ewes with energy and protein restriction during lactation period Retorno a atividade cíclica em ovelhas deslanadas submetidas à restrição calórica ou protéica durante o período de lactação

    Directory of Open Access Journals (Sweden)

    Eleonora Araújo Barbosa

    2009-06-01

    Full Text Available Inadequate ingestion of nutrients in quality and quantities is common cause of infertility in ewe and mechanisms involved between nutrition and reproduction is changeable. The aim of this work was to evaluate the energy or protein restriction during lactation in ewe on return of reproductive cyclic activity. Twenty one females in post-partum was divided randomly in 3 treatments: control treatment (CT, diet supply the requirements for maintenance and lactation, caloric restriction (CRT, supplied ½ of the diet of the CT, protein restriction (PRT, supplied 1/3 of the protein of the CT. Trans-rectal ultrasound was performed to ovary evaluation weekly and the body weight were measured biweekly. Effect of treatment on number (P<0.0001 and diameter (P<0.0001 of follicle was observed. PRT (3.32 ± 1.79; 1.45 ± 0.15 was lesser CRT (4.12 ± 1.98 ; 1.55 ± 0.09 and CT (4.94±2.01; 3.32 ± 0.22. Interaction between treatment and week in follicles lesser or equal 3 mm (P=0,0007 and greater of 3 mm (P<0,0001 added the presence of corpus luteum (P=0.0319 in the CT demonstrated effect of energy or protein restriction in the cyclic pattens of nursing sheep. On the basis of the results conclude that the nutritional restriction affects the return of the cyclical activity in the post-partum of sheep.A ingestão inadequada de nutrientes em qualidade e quantidade influencia a fertilidade das ovelhas, sendo variados os mecanismos envolvidos na inter-relação nutrição e reprodução. Objetivou-se avaliar os efeitos da restrição calórica ou protéica em ovelhas, durante a fase de lactação, sobre o desenvolvimento folicular e retorno à atividade cíclica pós-parto. Foram utilizadas 21 ovelhas SRD, recém-paridas, divididas aleatoriamente em três tratamentos: tratamento controle (TC - dieta que atendia aos requerimentos de mantença e lactação, restrição calórica (TRC - fornecia 1/2 da dieta do TC, restrição protéica (TRP - fornecia 1/3 da prote

  16. Maximizing ROI (return on information)

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, B.

    2000-05-01

    The role and importance of managing information are discussed, underscoring the importance by quoting from the report of the International Data Corporation, according to which Fortune 500 companies lost $ 12 billion in 1999 due to inefficiencies resulting from intellectual re-work, substandard performance , and inability to find knowledge resources. The report predicts that this figure will rise to $ 31.5 billion by 2003. Key impediments to implementing knowledge management systems are identified as : the cost and human resources requirement of deployment; inflexibility of historical systems to adapt to change; and the difficulty of achieving corporate acceptance of inflexible software products that require changes in 'normal' ways of doing business. The author recommends the use of model, document and rule-independent systems with a document centered interface (DCI), employing rapid application development (RAD) and object technologies and visual model development, which eliminate these problems, making it possible for companies to maximize their return on information (ROI), and achieve substantial savings in implementation costs.

  17. Sensitivity and uncertainty analysis of the PATHWAY radionuclide transport model

    International Nuclear Information System (INIS)

    Otis, M.D.

    1983-01-01

    Procedures were developed for the uncertainty and sensitivity analysis of a dynamic model of radionuclide transport through human food chains. Uncertainty in model predictions was estimated by propagation of parameter uncertainties using a Monte Carlo simulation technique. Sensitivity of model predictions to individual parameters was investigated using the partial correlation coefficient of each parameter with model output. Random values produced for the uncertainty analysis were used in the correlation analysis for sensitivity. These procedures were applied to the PATHWAY model which predicts concentrations of radionuclides in foods grown in Nevada and Utah and exposed to fallout during the period of atmospheric nuclear weapons testing in Nevada. Concentrations and time-integrated concentrations of iodine-131, cesium-136, and cesium-137 in milk and other foods were investigated. 9 figs., 13 tabs

  18. Bayesian analysis for uncertainty estimation of a canopy transpiration model

    Science.gov (United States)

    Samanta, S.; Mackay, D. S.; Clayton, M. K.; Kruger, E. L.; Ewers, B. E.

    2007-04-01

    A Bayesian approach was used to fit a conceptual transpiration model to half-hourly transpiration rates for a sugar maple (Acer saccharum) stand collected over a 5-month period and probabilistically estimate its parameter and prediction uncertainties. The model used the Penman-Monteith equation with the Jarvis model for canopy conductance. This deterministic model was extended by adding a normally distributed error term. This extension enabled using Markov chain Monte Carlo simulations to sample the posterior parameter distributions. The residuals revealed approximate conformance to the assumption of normally distributed errors. However, minor systematic structures in the residuals at fine timescales suggested model changes that would potentially improve the modeling of transpiration. Results also indicated considerable uncertainties in the parameter and transpiration estimates. This simple methodology of uncertainty analysis would facilitate the deductive step during the development cycle of deterministic conceptual models by accounting for these uncertainties while drawing inferences from data.

  19. Risk-return of Belgian SRI funds

    OpenAIRE

    Van Liedekerke, Luc; De Moor, Lieven; Vanwalleghem, Dieter

    2007-01-01

    We analyse the risk-return profile of Belgian SRI funds versus conventional investment funds. We apply a four-factor conditional Carhart model to establish whether there are significant differences in risk-return profile between an SRI portfolio and a conventional portfolio and test for learning effects in SRI funds. We show that there is no difference in risk-return profile between SRI and conventional funds. If return is not the problem, then what is it that limits the development of an SRI...

  20. Money growth and aggregate stock returns

    OpenAIRE

    Böing, Tobias; Stadtmann, Georg

    2016-01-01

    We empirically evaluate the predictive power of money growth measured by M2 for stock returns of the S&P 500 index. We use monthly US data and predict multiperiod returns over 1, 3, and 5 years with long-horizon regressions. In-sample regressions show that money growth is useful for predicting returns. Higher recent money growth has a significantly negative effect on subsequent returns of the S&P 500. An out-of-sample analysis shows that a simple model with money growth as a single predictor ...

  1. Intrinsic Uncertainties in Modeling Complex Systems.

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Curtis S; Bramson, Aaron L.; Ames, Arlo L.

    2014-09-01

    Models are built to understand and predict the behaviors of both natural and artificial systems. Because it is always necessary to abstract away aspects of any non-trivial system being modeled, we know models can potentially leave out important, even critical elements. This reality of the modeling enterprise forces us to consider the prospective impacts of those effects completely left out of a model - either intentionally or unconsidered. Insensitivity to new structure is an indication of diminishing returns. In this work, we represent a hypothetical unknown effect on a validated model as a finite perturba- tion whose amplitude is constrained within a control region. We find robustly that without further constraints, no meaningful bounds can be placed on the amplitude of a perturbation outside of the control region. Thus, forecasting into unsampled regions is a very risky proposition. We also present inherent difficulties with proper time discretization of models and representing in- herently discrete quantities. We point out potentially worrisome uncertainties, arising from math- ematical formulation alone, which modelers can inadvertently introduce into models of complex systems. Acknowledgements This work has been funded under early-career LDRD project #170979, entitled "Quantify- ing Confidence in Complex Systems Models Having Structural Uncertainties", which ran from 04/2013 to 09/2014. We wish to express our gratitude to the many researchers at Sandia who con- tributed ideas to this work, as well as feedback on the manuscript. In particular, we would like to mention George Barr, Alexander Outkin, Walt Beyeler, Eric Vugrin, and Laura Swiler for provid- ing invaluable advice and guidance through the course of the project. We would also like to thank Steven Kleban, Amanda Gonzales, Trevor Manzanares, and Sarah Burwell for their assistance in managing project tasks and resources.

  2. Optimal portfolio design to reduce climate-related conservation uncertainty in the Prairie Pothole Region.

    Science.gov (United States)

    Ando, Amy W; Mallory, Mindy L

    2012-04-24

    Climate change is likely to alter the spatial distributions of species and habitat types but the nature of such change is uncertain. Thus, climate change makes it difficult to implement standard conservation planning paradigms. Previous work has suggested some approaches to cope with such uncertainty but has not harnessed all of the benefits of risk diversification. We adapt Modern Portfolio Theory (MPT) to optimal spatial targeting of conservation activity, using wetland habitat conservation in the Prairie Pothole Region (PPR) as an example. This approach finds the allocations of conservation activity among subregions of the planning area that maximize the expected conservation returns for a given level of uncertainty or minimize uncertainty for a given expected level of returns. We find that using MPT instead of simple diversification in the PPR can achieve a value of the conservation objective per dollar spent that is 15% higher for the same level of risk. MPT-based portfolios can also have 21% less uncertainty over benefits or 6% greater expected benefits than the current portfolio of PPR conservation. Total benefits from conservation investment are higher if returns are defined in terms of benefit-cost ratios rather than benefits alone. MPT-guided diversification can work to reduce the climate-change-induced uncertainty of future ecosystem-service benefits from many land policy and investment initiatives, especially when outcomes are negatively correlated between subregions of a planning area.

  3. Optimal portfolio design to reduce climate-related conservation uncertainty in the Prairie Pothole Region

    Science.gov (United States)

    Ando, Amy W.; Mallory, Mindy L.

    2012-01-01

    Climate change is likely to alter the spatial distributions of species and habitat types but the nature of such change is uncertain. Thus, climate change makes it difficult to implement standard conservation planning paradigms. Previous work has suggested some approaches to cope with such uncertainty but has not harnessed all of the benefits of risk diversification. We adapt Modern Portfolio Theory (MPT) to optimal spatial targeting of conservation activity, using wetland habitat conservation in the Prairie Pothole Region (PPR) as an example. This approach finds the allocations of conservation activity among subregions of the planning area that maximize the expected conservation returns for a given level of uncertainty or minimize uncertainty for a given expected level of returns. We find that using MPT instead of simple diversification in the PPR can achieve a value of the conservation objective per dollar spent that is 15% higher for the same level of risk. MPT-based portfolios can also have 21% less uncertainty over benefits or 6% greater expected benefits than the current portfolio of PPR conservation. Total benefits from conservation investment are higher if returns are defined in terms of benefit–cost ratios rather than benefits alone. MPT-guided diversification can work to reduce the climate-change–induced uncertainty of future ecosystem-service benefits from many land policy and investment initiatives, especially when outcomes are negatively correlated between subregions of a planning area. PMID:22451914

  4. Do Orthopaedic Surgeons Acknowledge Uncertainty?

    Science.gov (United States)

    Teunis, Teun; Janssen, Stein; Guitton, Thierry G; Ring, David; Parisien, Robert

    2016-06-01

    Much of the decision-making in orthopaedics rests on uncertain evidence. Uncertainty is therefore part of our normal daily practice, and yet physician uncertainty regarding treatment could diminish patients' health. It is not known if physician uncertainty is a function of the evidence alone or if other factors are involved. With added experience, uncertainty could be expected to diminish, but perhaps more influential are things like physician confidence, belief in the veracity of what is published, and even one's religious beliefs. In addition, it is plausible that the kind of practice a physician works in can affect the experience of uncertainty. Practicing physicians may not be immediately aware of these effects on how uncertainty is experienced in their clinical decision-making. We asked: (1) Does uncertainty and overconfidence bias decrease with years of practice? (2) What sociodemographic factors are independently associated with less recognition of uncertainty, in particular belief in God or other deity or deities, and how is atheism associated with recognition of uncertainty? (3) Do confidence bias (confidence that one's skill is greater than it actually is), degree of trust in the orthopaedic evidence, and degree of statistical sophistication correlate independently with recognition of uncertainty? We created a survey to establish an overall recognition of uncertainty score (four questions), trust in the orthopaedic evidence base (four questions), confidence bias (three questions), and statistical understanding (six questions). Seven hundred six members of the Science of Variation Group, a collaboration that aims to study variation in the definition and treatment of human illness, were approached to complete our survey. This group represents mainly orthopaedic surgeons specializing in trauma or hand and wrist surgery, practicing in Europe and North America, of whom the majority is involved in teaching. Approximately half of the group has more than 10 years

  5. Time-bound product returns and optimal order quantities for mass merchandisers

    Science.gov (United States)

    Yu, Min-Chun; Goh, Mark

    2012-01-01

    The return guidelines for a mass merchandiser usually entail a grace period, a markdown on the original price and the condition of the returned items. This research utilises eight scenarios formed from the variation of possible return guidelines to model the cost functions of single-product categories for a typical mass merchandiser. Models for the eight scenarios are developed and solved with the objective of maximising the expected profit so as to obtain closed form solutions for the associated optimal order quantity. An illustrative example and sensitivity analysis are provided to demonstrate the applicability of the model. Our results show that merchandisers who allow for returns within a time window, albeit with a penalty cost imposed and the returned products being recoverable, should plan for larger order amounts as such products do not affect the business. Similarly, the merchandisers who allow for returns beyond a grace period and without any penalty charges, but where the returned products are irrecoverable, should manage their stocks in this category more judiciously by ordering as little as possible so as to limit the number of returns and carefully consider the effects of their customer satisfaction-guaranteed policies, if any.

  6. Policy for returning to fisheries in Korea

    Directory of Open Access Journals (Sweden)

    Jihoon Kim

    2016-07-01

    Full Text Available Korea’s fishing industry is currently facing problems involving an aging society and lack of successors in fishing villages. Therefore, the Korea Ministry of Oceans and Fisheries (KMOF has implemented a policy supporting U-turn fishers, who leave their place of origin for a job and then return home or move to where they can work in the fishing industry. Moreover, some local governments have established a policy for U-turn fishers. The KMOF policy is a financial support program with low interest rates and lengthy reimbursement periods; however, few beneficiaries exist. Meanwhile, local government policy benefits most persons in corresponding areas. However, the sums are relatively small, and only two local governments have enacted the policy. This study determines the performance of the policy through indepth interviews and a survey. The results indicate that KMOF policy may be limited in terms of its scope. In addition, noneconomic support programs, such as fishing education, harmony between existing fishers, and the acquisition of fishery rights, are required. The number of U-turn fishers will continue to increase as the baby boomer generation nears retirement and unemployment of youth increases. As such, the Korean government needs to improve the policy in keeping with the times.

  7. Confronting the Uncertainty in Aerosol Forcing Using Comprehensive Observational Data

    Science.gov (United States)

    Johnson, J. S.; Regayre, L. A.; Yoshioka, M.; Pringle, K.; Sexton, D.; Lee, L.; Carslaw, K. S.

    2017-12-01

    The effect of aerosols on cloud droplet concentrations and radiative properties is the largest uncertainty in the overall radiative forcing of climate over the industrial period. In this study, we take advantage of a large perturbed parameter ensemble of simulations from the UK Met Office HadGEM-UKCA model (the aerosol component of the UK Earth System Model) to comprehensively sample uncertainty in aerosol forcing. Uncertain aerosol and atmospheric parameters cause substantial aerosol forcing uncertainty in climatically important regions. As the aerosol radiative forcing itself is unobservable, we investigate the potential for observations of aerosol and radiative properties to act as constraints on the large forcing uncertainty. We test how eight different theoretically perfect aerosol and radiation observations can constrain the forcing uncertainty over Europe. We find that the achievable constraint is weak unless many diverse observations are used simultaneously. This is due to the complex relationships between model output responses and the multiple interacting parameter uncertainties: compensating model errors mean there are many ways to produce the same model output (known as model equifinality) which impacts on the achievable constraint. However, using all eight observable quantities together we show that the aerosol forcing uncertainty can potentially be reduced by around 50%. This reduction occurs as we reduce a large sample of model variants (over 1 million) that cover the full parametric uncertainty to around 1% that are observationally plausible.Constraining the forcing uncertainty using real observations is a more complex undertaking, in which we must account for multiple further uncertainties including measurement uncertainties, structural model uncertainties and the model discrepancy from reality. Here, we make a first attempt to determine the true potential constraint on the forcing uncertainty from our model that is achievable using a comprehensive

  8. SECTORAL RISK AND RETURN FOR COMPANIES IN ROMANIA

    Directory of Open Access Journals (Sweden)

    Anis Cecilia

    2012-12-01

    Full Text Available probability that cash flows or return will vary from expectations. Standard corporate finance theory supposes that a company chooses a capital structure that maximizes company value. A fundamental idea in finance is the relationship between risk and return. The greater the amount of risk that an investor is willing to take on, the greater the potential return. The reason for this is that investors need to be compensated for taking on additional risk. Why put capital at significant risk for a return that is no higher than the return on government bonds? Or expect higher than averages returns from low-risk activities? It is impossible to separate measuring the performance of a company from the risks that the management takes to achieve it.In most aspects of company operations, risk assessment plays a different but equally important, role. It is an integral part of informed decision taking in achieving performance. Risk assessment is involved from the highest level in strategic choices about what activities to undertake, what assets to buy or what markets to serve all the way to detailed operational decisions about whether to accept payment in foreign currencies and the adequacy of safety measures in the workplace. It plays a part whether or not an organization is aware of managing risk and many managers feel that their instinct and judgment are enough – a behavior risk. The danger is that this leaves company risk unplanned and unmanaged. This paper proposes a framework where we realized a study cases: we test if return on assets and return on equity has influence on the risk, both on long and short term. For this purposes, we conduct an empirical research that covers 59 selected companies traded at the Bucharest Stock Exchange within the time period 1999-2010. For this study our results reveal that dynamic global risk can be associated to a low intensity with total assets performance of the company’s. Investments efficiency and the

  9. Preliminary Results on Uncertainty Quantification for Pattern Analytics

    Energy Technology Data Exchange (ETDEWEB)

    Stracuzzi, David John [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Brost, Randolph [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Chen, Maximillian Gene [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Malinas, Rebecca [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Peterson, Matthew Gregor [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Phillips, Cynthia A. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Robinson, David G. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Woodbridge, Diane [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    This report summarizes preliminary research into uncertainty quantification for pattern ana- lytics within the context of the Pattern Analytics to Support High-Performance Exploitation and Reasoning (PANTHER) project. The primary focus of PANTHER was to make large quantities of remote sensing data searchable by analysts. The work described in this re- port adds nuance to both the initial data preparation steps and the search process. Search queries are transformed from does the specified pattern exist in the data? to how certain is the system that the returned results match the query? We show example results for both data processing and search, and discuss a number of possible improvements for each.

  10. Multifactor analysis of multiscaling in volatility return intervals.

    Science.gov (United States)

    Wang, Fengzhong; Yamasaki, Kazuko; Havlin, Shlomo; Stanley, H Eugene

    2009-01-01

    We study the volatility time series of 1137 most traded stocks in the U.S. stock markets for the two-year period 2001-2002 and analyze their return intervals tau , which are time intervals between volatilities above a given threshold q . We explore the probability density function of tau , P_(q)(tau) , assuming a stretched exponential function, P_(q)(tau) approximately e;(-tau;(gamma)) . We find that the exponent gamma depends on the threshold in the range between q=1 and 6 standard deviations of the volatility. This finding supports the multiscaling nature of the return interval distribution. To better understand the multiscaling origin, we study how gamma depends on four essential factors, capitalization, risk, number of trades, and return. We show that gamma depends on the capitalization, risk, and return but almost does not depend on the number of trades. This suggests that gamma relates to the portfolio selection but not on the market activity. To further characterize the multiscaling of individual stocks, we fit the moments of tau , mu_(m) identical with(tautau);(m);(1m) , in the range of 10portfolio optimization.

  11. Enterprise size and return to work after stroke.

    Science.gov (United States)

    Hannerz, Harald; Ferm, Linnea; Poulsen, Otto M; Pedersen, Betina Holbæk; Andersen, Lars L

    2012-12-01

    It has been hypothesised that return to work rates among sick-listed workers increases with enterprise size. The aim of the present study was to estimate the effect of enterprise size on the odds of returning to work among previously employed stroke patients in Denmark, 2000-2006. We used a prospective design with a 2 year follow-up period. The study population consisted of 13,178 stroke patients divided into four enterprise sizes categories, according to the place of their employment prior to the stroke: micro (1-9 employees), small (10-49 employees), medium (50-249 employees) and large (>250 employees). The analysis was based on nationwide data on enterprise size from Statistics Denmark merged with data from the Danish occupational hospitalisation register. We found a statistically significant association (p = 0.034); each increase in enterprise size category was followed by an increase in the estimated odds of returning to work. The chances of returning to work after stroke increases as the size of enterprise increases. Preventive efforts and research aimed at finding ways of mitigating the effect are warranted.

  12. Multifactor analysis of multiscaling in volatility return intervals

    Science.gov (United States)

    Wang, Fengzhong; Yamasaki, Kazuko; Havlin, Shlomo; Stanley, H. Eugene

    2009-01-01

    We study the volatility time series of 1137 most traded stocks in the U.S. stock markets for the two-year period 2001-2002 and analyze their return intervals τ , which are time intervals between volatilities above a given threshold q . We explore the probability density function of τ , Pq(τ) , assuming a stretched exponential function, Pq(τ)˜e-τγ . We find that the exponent γ depends on the threshold in the range between q=1 and 6 standard deviations of the volatility. This finding supports the multiscaling nature of the return interval distribution. To better understand the multiscaling origin, we study how γ depends on four essential factors, capitalization, risk, number of trades, and return. We show that γ depends on the capitalization, risk, and return but almost does not depend on the number of trades. This suggests that γ relates to the portfolio selection but not on the market activity. To further characterize the multiscaling of individual stocks, we fit the moments of τ , μm≡⟨(τ/⟨τ⟩)m⟩1/m , in the range of 10portfolio optimization.

  13. Site utility system optimization with operation adjustment under uncertainty

    International Nuclear Information System (INIS)

    Sun, Li; Gai, Limei; Smith, Robin

    2017-01-01

    Highlights: • Uncertainties are classified into time-based and probability-based uncertain factors. • Multi-period operation and recourses deal with uncertainty implementation. • Operation scheduling are specified at the design stage to deal with uncertainties. • Steam mains superheating affects steam distribution and power generation in the system. - Abstract: Utility systems must satisfy process energy and power demands under varying conditions. The system performance is decided by the system configuration and individual equipment operating load for boilers, gas turbines, steam turbines, condensers, and let down valves. Steam mains conditions in terms of steam pressures and steam superheating also play important roles on steam distribution in the system and power generation by steam expansion in steam turbines, and should be included in the system optimization. Uncertainties such as process steam power demand changes and electricity price fluctuations should be included in the system optimization to eliminate as much as possible the production loss caused by steam power deficits due to uncertainties. In this paper, uncertain factors are classified into time-based and probability-based uncertain factors, and operation scheduling containing multi-period equipment load sharing, redundant equipment start up, and electricity import to compensate for power deficits, have been presented to deal with the happens of uncertainties, and are formulated as a multi-period item and a recourse item in the optimization model. There are two case studies in this paper. One case illustrates the system design to determine system configuration, equipment selection, and system operation scheduling at the design stage to deal with uncertainties. The other case provides operational optimization scenarios for an existing system, especially when the steam superheating varies. The proposed method can provide practical guidance to system energy efficiency improvement.

  14. Reintegration of Pakistani return migrants from the Middle East in the domestic labour market.

    Science.gov (United States)

    Arif, G M

    1998-01-01

    This study compared the unemployment rates among return migrants and nonmigrants and examined the reintegration pattern of returnees in the domestic labor market. The study utilized three data sets: the 1980 World Bank Survey of Return Migrant Households; the 1986 ILO/ARTEP Survey of Return Migrant Households; the 1991 Pakistan Integrated Household Survey. Findings showed that unemployment rates were much higher among return migrants than nonmigrants. Although this difference narrowed with the passage of time, even among those who returned to Pakistan at least 18 months prior to the surveys, more than 10% of workers were unemployed. The multivariate analysis further showed that returnees, irrespective of the period elapsed since their return, were more likely to be unemployed than nonmigrants. With respect to the reintegration pattern of return migrants, the study revealed that variables indicating their human capital, such as occupation and pre-migration and during-migration work experience, appear to have a greater influence on their post-return adjustment than the variables related to economic positions such as savings. The results also showed that the types of jobs unemployed returnees were looking for differed substantially from those held by employed return migrants. A possibility was that unemployed returnees could not save enough from their overseas earnings to become self-employed. Thus, provision of credit for self-employment seems to be the right way to accommodate these workers.

  15. Analisis Karakteristik Perusahaan Dan Ekonomi Makro Pada Return Saham Syariah Dan Non Syariah

    Directory of Open Access Journals (Sweden)

    Ardi Hamzah

    2011-10-01

    Full Text Available The objectives of this paper are to determine, to examine, and to test whether firm characteristic and macro economics are the important discriminators for return of syariah and non syariah stock; to determine whether there are any differences in return of some syariah and non syariah stock; to determine and to test whether there is a relationship between return and firm characteristic and macro economis in some syariah and non syariah stock. The total sample is 300 stock that were taken each from 150 for syariah stock and 150 for non syariah stock for period 2005 – 2009. The study also showed that there is a difference in return between syariah and non syariah stock. Finally,with regression analysis indicated that partially price book value, price earnings ratio, and kurs rupiah on dollar significantly effect on return of syariah stock, while for return of non syariah stock only kurs rupiah on dollar that significantly effect on return of non syariah stock. For testing with simultant regression indicate firm characteristic and macro economics significantly effect on return of syariah stock, while at return of non syariah stock not significantly effect.

  16. Maximizing your return on people.

    Science.gov (United States)

    Bassi, Laurie; McMurrer, Daniel

    2007-03-01

    Though most traditional HR performance metrics don't predict organizational performance, alternatives simply have not existed--until now. During the past ten years, researchers Laurie Bassi and Daniel McMurrer have worked to develop a system that allows executives to assess human capital management (HCM) and to use those metrics both to predict organizational performance and to guide organizations' investments in people. The new framework is based on a core set of HCM drivers that fall into five major categories: leadership practices, employee engagement, knowledge accessibility, workforce optimization, and organizational learning capacity. By employing rigorously designed surveys to score a company on the range of HCM practices across the five categories, it's possible to benchmark organizational HCM capabilities, identify HCM strengths and weaknesses, and link improvements or back-sliding in specific HCM practices with improvements or shortcomings in organizational performance. The process requires determining a "maturity" score for each practice, based on a scale of 1 (low) to 5 (high). Over time, evolving maturity scores from multiple surveys can reveal progress in each of the HCM practices and help a company decide where to focus improvement efforts that will have a direct impact on performance. The authors draw from their work with American Standard, South Carolina's Beaufort County School District, and a bevy of financial firms to show how improving HCM scores led to increased sales, safety, academic test scores, and stock returns. Bassi and McMurrer urge HR departments to move beyond the usual metrics and begin using HCM measurement tools to gauge how well people are managed and developed throughout the organization. In this new role, according to the authors, HR can take on strategic responsibility and ensure that superior human capital management becomes central to the organization's culture.

  17. RUMINATIONS ON NDA MEASUREMENT UNCERTAINTY COMPARED TO DA UNCERTAINTY

    Energy Technology Data Exchange (ETDEWEB)

    Salaymeh, S.; Ashley, W.; Jeffcoat, R.

    2010-06-17

    It is difficult to overestimate the importance that physical measurements performed with nondestructive assay instruments play throughout the nuclear fuel cycle. They underpin decision making in many areas and support: criticality safety, radiation protection, process control, safeguards, facility compliance, and waste measurements. No physical measurement is complete or indeed meaningful, without a defensible and appropriate accompanying statement of uncertainties and how they combine to define the confidence in the results. The uncertainty budget should also be broken down in sufficient detail suitable for subsequent uses to which the nondestructive assay (NDA) results will be applied. Creating an uncertainty budget and estimating the total measurement uncertainty can often be an involved process, especially for non routine situations. This is because data interpretation often involves complex algorithms and logic combined in a highly intertwined way. The methods often call on a multitude of input data subject to human oversight. These characteristics can be confusing and pose a barrier to developing and understanding between experts and data consumers. ASTM subcommittee C26-10 recognized this problem in the context of how to summarize and express precision and bias performance across the range of standards and guides it maintains. In order to create a unified approach consistent with modern practice and embracing the continuous improvement philosophy a consensus arose to prepare a procedure covering the estimation and reporting of uncertainties in non destructive assay of nuclear materials. This paper outlines the needs analysis, objectives and on-going development efforts. In addition to emphasizing some of the unique challenges and opportunities facing the NDA community we hope this article will encourage dialog and sharing of best practice and furthermore motivate developers to revisit the treatment of measurement uncertainty.

  18. Ruminations On NDA Measurement Uncertainty Compared TO DA Uncertainty

    International Nuclear Information System (INIS)

    Salaymeh, S.; Ashley, W.; Jeffcoat, R.

    2010-01-01

    It is difficult to overestimate the importance that physical measurements performed with nondestructive assay instruments play throughout the nuclear fuel cycle. They underpin decision making in many areas and support: criticality safety, radiation protection, process control, safeguards, facility compliance, and waste measurements. No physical measurement is complete or indeed meaningful, without a defensible and appropriate accompanying statement of uncertainties and how they combine to define the confidence in the results. The uncertainty budget should also be broken down in sufficient detail suitable for subsequent uses to which the nondestructive assay (NDA) results will be applied. Creating an uncertainty budget and estimating the total measurement uncertainty can often be an involved process, especially for non routine situations. This is because data interpretation often involves complex algorithms and logic combined in a highly intertwined way. The methods often call on a multitude of input data subject to human oversight. These characteristics can be confusing and pose a barrier to developing and understanding between experts and data consumers. ASTM subcommittee C26-10 recognized this problem in the context of how to summarize and express precision and bias performance across the range of standards and guides it maintains. In order to create a unified approach consistent with modern practice and embracing the continuous improvement philosophy a consensus arose to prepare a procedure covering the estimation and reporting of uncertainties in non destructive assay of nuclear materials. This paper outlines the needs analysis, objectives and on-going development efforts. In addition to emphasizing some of the unique challenges and opportunities facing the NDA community we hope this article will encourage dialog and sharing of best practice and furthermore motivate developers to revisit the treatment of measurement uncertainty.

  19. What stock market returns to expect for the future?

    Science.gov (United States)

    Diamond, P A

    2000-01-01

    In evaluating proposals for reforming Social Security that involve stock investments, the Office of the Chief Actuary (OCACT) has generally used a 7.0 percent real return for stocks. The 1994-96 Advisory Council specified that OCACT should use that return in making its 75-year projections of investment-based reform proposals. The assumed ultimate real return on Treasury bonds of 3.0 percent implies a long-run equity premium of 4.0 percent. There are two equity-premium concepts: the realized equity premium, which is measured by the actual rates of return; and the required equity premium, which investors expect to receive for being willing to hold available stocks and bonds. Over the past two centuries, the realized premium was 3.5 percent on average, but 5.2 percent for 1926 to 1998. Some critics argue that the 7.0 percent projected stock returns are too high. They base their arguments on recent developments in the capital market, the current high value of the stock market, and the expectation of slower economic growth. Increased use of mutual funds and the decline in their costs suggest a lower required premium, as does the rising fraction of the American public investing in stocks. The size of the decrease is limited, however, because the largest cost savings do not apply to the very wealthy and to large institutional investors, who hold a much larger share of the stock market's total value than do new investors. These trends suggest a lower equity premium for projections than the 5.2 percent of the past 75 years. Also, a declining required premium is likely to imply a temporary increase in the realized premium because a rising willingness to hold stocks tends to increase their price. Therefore, it would be a mistake during a transition period to extrapolate what may be a temporarily high realized return. In the standard (Solow) economic growth model, an assumption of slower long-run growth lowers the marginal product of capital if the savings rate is constant

  20. Estimating decades-long trends in petroleum field energy return on investment (EROI) with an engineering-based model

    Science.gov (United States)

    Tripathi, Vinay S.

    2017-01-01

    This paper estimates changes in the energy return on investment (EROI) for five large petroleum fields over time using the Oil Production Greenhouse Gas Emissions Estimator (OPGEE). The modeled fields include Cantarell (Mexico), Forties (U.K.), Midway-Sunset (U.S.), Prudhoe Bay (U.S.), and Wilmington (U.S.). Data on field properties and production/processing parameters were obtained from a combination of government and technical literature sources. Key areas of uncertainty include details of the oil and gas surface processing schemes. We aim to explore how long-term trends in depletion at major petroleum fields change the effective energetic productivity of petroleum extraction. Four EROI ratios are estimated for each field as follows: The net energy ratio (NER) and external energy ratio (EER) are calculated, each using two measures of energy outputs, (1) oil-only and (2) all energy outputs. In all cases, engineering estimates of inputs are used rather than expenditure-based estimates (including off-site indirect energy use and embodied energy). All fields display significant declines in NER over the modeling period driven by a combination of (1) reduced petroleum production and (2) increased energy expenditures on recovery methods such as the injection of water, steam, or gas. The fields studied had NER reductions ranging from 46% to 88% over the modeling periods (accounting for all energy outputs). The reasons for declines in EROI differ by field. Midway-Sunset experienced a 5-fold increase in steam injected per barrel of oil produced. In contrast, Prudhoe Bay has experienced nearly a 30-fold increase in amount of gas processed and reinjected per unit of oil produced. In contrast, EER estimates are subject to greater variability and uncertainty due to the relatively small magnitude of external energy investments in most cases. PMID:28178318

  1. Estimating decades-long trends in petroleum field energy return on investment (EROI) with an engineering-based model.

    Science.gov (United States)

    Tripathi, Vinay S; Brandt, Adam R

    2017-01-01

    This paper estimates changes in the energy return on investment (EROI) for five large petroleum fields over time using the Oil Production Greenhouse Gas Emissions Estimator (OPGEE). The modeled fields include Cantarell (Mexico), Forties (U.K.), Midway-Sunset (U.S.), Prudhoe Bay (U.S.), and Wilmington (U.S.). Data on field properties and production/processing parameters were obtained from a combination of government and technical literature sources. Key areas of uncertainty include details of the oil and gas surface processing schemes. We aim to explore how long-term trends in depletion at major petroleum fields change the effective energetic productivity of petroleum extraction. Four EROI ratios are estimated for each field as follows: The net energy ratio (NER) and external energy ratio (EER) are calculated, each using two measures of energy outputs, (1) oil-only and (2) all energy outputs. In all cases, engineering estimates of inputs are used rather than expenditure-based estimates (including off-site indirect energy use and embodied energy). All fields display significant declines in NER over the modeling period driven by a combination of (1) reduced petroleum production and (2) increased energy expenditures on recovery methods such as the injection of water, steam, or gas. The fields studied had NER reductions ranging from 46% to 88% over the modeling periods (accounting for all energy outputs). The reasons for declines in EROI differ by field. Midway-Sunset experienced a 5-fold increase in steam injected per barrel of oil produced. In contrast, Prudhoe Bay has experienced nearly a 30-fold increase in amount of gas processed and reinjected per unit of oil produced. In contrast, EER estimates are subject to greater variability and uncertainty due to the relatively small magnitude of external energy investments in most cases.

  2. Estimating decades-long trends in petroleum field energy return on investment (EROI with an engineering-based model.

    Directory of Open Access Journals (Sweden)

    Vinay S Tripathi

    Full Text Available This paper estimates changes in the energy return on investment (EROI for five large petroleum fields over time using the Oil Production Greenhouse Gas Emissions Estimator (OPGEE. The modeled fields include Cantarell (Mexico, Forties (U.K., Midway-Sunset (U.S., Prudhoe Bay (U.S., and Wilmington (U.S.. Data on field properties and production/processing parameters were obtained from a combination of government and technical literature sources. Key areas of uncertainty include details of the oil and gas surface processing schemes. We aim to explore how long-term trends in depletion at major petroleum fields change the effective energetic productivity of petroleum extraction. Four EROI ratios are estimated for each field as follows: The net energy ratio (NER and external energy ratio (EER are calculated, each using two measures of energy outputs, (1 oil-only and (2 all energy outputs. In all cases, engineering estimates of inputs are used rather than expenditure-based estimates (including off-site indirect energy use and embodied energy. All fields display significant declines in NER over the modeling period driven by a combination of (1 reduced petroleum production and (2 increased energy expenditures on recovery methods such as the injection of water, steam, or gas. The fields studied had NER reductions ranging from 46% to 88% over the modeling periods (accounting for all energy outputs. The reasons for declines in EROI differ by field. Midway-Sunset experienced a 5-fold increase in steam injected per barrel of oil produced. In contrast, Prudhoe Bay has experienced nearly a 30-fold increase in amount of gas processed and reinjected per unit of oil produced. In contrast, EER estimates are subject to greater variability and uncertainty due to the relatively small magnitude of external energy investments in most cases.

  3. Distributionally Robust Return-Risk Optimization Models and Their Applications

    Directory of Open Access Journals (Sweden)

    Li Yang

    2014-01-01

    Full Text Available Based on the risk control of conditional value-at-risk, distributionally robust return-risk optimization models with box constraints of random vector are proposed. They describe uncertainty in both the distribution form and moments (mean and covariance matrix of random vector. It is difficult to solve them directly. Using the conic duality theory and the minimax theorem, the models are reformulated as semidefinite programming problems, which can be solved by interior point algorithms in polynomial time. An important theoretical basis is therefore provided for applications of the models. Moreover, an application of the models to a practical example of portfolio selection is considered, and the example is evaluated using a historical data set of four stocks. Numerical results show that proposed methods are robust and the investment strategy is safe.

  4. 14 CFR 271.8 - Rate period.

    Science.gov (United States)

    2010-01-01

    ... Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS GUIDELINES FOR SUBSIDIZING AIR CARRIERS PROVIDING ESSENTIAL AIR TRANSPORTATION § 271.8 Rate period... place essential air service level; or (5) The uncertainties of the market or other circumstances warrant...

  5. Uncertainty Quantification in Numerical Aerodynamics

    KAUST Repository

    Litvinenko, Alexander

    2017-05-16

    We consider uncertainty quantification problem in aerodynamic simulations. We identify input uncertainties, classify them, suggest an appropriate statistical model and, finally, estimate propagation of these uncertainties into the solution (pressure, velocity and density fields as well as the lift and drag coefficients). The deterministic problem under consideration is a compressible transonic Reynolds-averaged Navier-Strokes flow around an airfoil with random/uncertain data. Input uncertainties include: uncertain angle of attack, the Mach number, random perturbations in the airfoil geometry, mesh, shock location, turbulence model and parameters of this turbulence model. This problem requires efficient numerical/statistical methods since it is computationally expensive, especially for the uncertainties caused by random geometry variations which involve a large number of variables. In numerical section we compares five methods, including quasi-Monte Carlo quadrature, polynomial chaos with coefficients determined by sparse quadrature and gradient-enhanced version of Kriging, radial basis functions and point collocation polynomial chaos, in their efficiency in estimating statistics of aerodynamic performance upon random perturbation to the airfoil geometry [D.Liu et al \\'17]. For modeling we used the TAU code, developed in DLR, Germany.

  6. Uncertainty in spatial planning proceedings

    Directory of Open Access Journals (Sweden)

    Aleš Mlakar

    2009-01-01

    Full Text Available Uncertainty is distinctive of spatial planning as it arises from the necessity to co-ordinate the various interests within the area, from the urgency of adopting spatial planning decisions, the complexity of the environment, physical space and society, addressing the uncertainty of the future and from the uncertainty of actually making the right decision. Response to uncertainty is a series of measures that mitigate the effects of uncertainty itself. These measures are based on two fundamental principles – standardization and optimization. The measures are related to knowledge enhancement and spatial planning comprehension, in the legal regulation of changes, in the existence of spatial planning as a means of different interests co-ordination, in the active planning and the constructive resolution of current spatial problems, in the integration of spatial planning and the environmental protection process, in the implementation of the analysis as the foundation of spatial planners activities, in the methods of thinking outside the parameters, in forming clear spatial concepts and in creating a transparent management spatial system and also in the enforcement the participatory processes.

  7. Return on Investment from Biochar Application

    Science.gov (United States)

    Current literature has yet to fully address the cost of biochar application or the return on investment to the grower. The objectives were to identify possible on-farm spreader equipment, spreader capacity, application expenses, and rate of return needed for growers to apply biochar economically. Bi...

  8. Aggregate Unemployment Decreases Individual Returns to Education

    Science.gov (United States)

    Ammermueller, Andreas; Kuckulenz, Anja; Zwick, Thomas

    2009-01-01

    Aggregate unemployment may affect individual returns to education through qualification-specific responses in participation and wage bargaining. This paper shows that an increase in regional unemployment by 1% decreases returns to education by 0.005 percentage points. This implies that higher skilled employees are better sheltered from labour…

  9. Slow return of displaced Southern Sudanese

    Directory of Open Access Journals (Sweden)

    Tim Morris

    2007-07-01

    Full Text Available The pace of repatriation of Sudanese refugees and return of IDP s to South Sudan has picked up but expectations at the time of the signing of the Comprehensive Peace Agreement (CPA CPA in January 2005 have yet to be realised. With all eyes on Darfur, assistance to sustain returns to South Sudan remains inadequate.

  10. Managing Returns in a Catalog Distribution Center

    Science.gov (United States)

    Gates, Joyce; Stuart, Julie Ann; Bonawi-tan, Winston; Loehr, Sarah

    2004-01-01

    The research team of the Purdue University in the United States developed an algorithm that considers several different factors, in addition to cost, to help catalog distribution centers process their returns more efficiently. A case study to teach the students important concepts involved in developing a solution to the returns disposition problem…

  11. 27 CFR 41.112 - Tax return.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2010-04-01 2010-04-01 false Tax return. 41.112 Section 41.112 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF... States Deferred Payment of Tax in Puerto Rico on Tobacco Products § 41.112 Tax return. The internal...

  12. Economic and accounting rates of return

    NARCIS (Netherlands)

    Feenstra, D.W.; Wang, H.

    2000-01-01

    The rate of return on invested capital is a central concept in financial analysis. The purpose of calculating the rate of return on investment in general is to measure the financial performance, to assess the desirability of a project and to make decisions on the valuation of firms. Financial

  13. The Returns to Quality in Graduate Education

    Science.gov (United States)

    Stevenson, Adam

    2016-01-01

    This paper estimates the monetary return to quality in US graduate education, controlling for cognitive ability and self-selection across award level, program quality, and field-of-study. In most program types, I cannot reject the hypothesis of no returns to either degree completion or program quality. Important exceptions include master's…

  14. Predictability of Returns and Cash Flows

    OpenAIRE

    Ralph S.J. Koijen; Stijn Van Nieuwerburgh

    2010-01-01

    We review the literature on return and cash-flow growth predictability from the perspective of the present-value identity. We focus predominantly on recent work. Our emphasis is on U.S. aggregate stock return predictability, but we also discuss evidence from other asset classes and countries.

  15. Legal institutions, strategic default, and stock returns

    NARCIS (Netherlands)

    Favara, G.; Schroth, E.; Valta, P.

    2008-01-01

    This paper studies the impact of legal institutions on stock returns. More specifically, we examine how differences in debt enforcement and creditor protection around the world affect stock returns of individual firms. We hypothesize that if legal institutions prevent shareholders from engaging in

  16. Return to Experience and Initial Wage Level

    DEFF Research Database (Denmark)

    Sørensen, Kenneth Lykke; Vejlin, Rune Majlund

    This paper estimates the relationship between initial wage and return to experience. We use a Mincer-like wage model to nonparametrically estimate this relationship allowing for an unobservable individual permanent effect in wages and unobservable individual return to experience. The relationship...

  17. Return to experience and initial wage level

    DEFF Research Database (Denmark)

    Sørensen, K.L.; Vejlin, R.

    2014-01-01

    This paper estimates the relationship between initial wage and return to experience. We use a Mincer-like wage model to non-parametrically estimate this relationship allowing for an unobservable individual permanent effect in wages and unobservable individual return to experience. The relationshi...

  18. Returnable containers: an example of reverse logistics

    NARCIS (Netherlands)

    L.G. Kroon (Leo); G.M.C. Vrijens

    1996-01-01

    textabstractConsiders the application of returnable containers as an example of reverse logistics. A returnable container is a type of secondary packaging that can be used several times in the same form, in contrast with traditional cardboard boxes. For this equipment to be used, a system for the

  19. Return to the workforce following infective endocarditis

    DEFF Research Database (Denmark)

    Butt, Jawad H.; Kragholm, Kristian; Dalager-Pedersen, Michael

    2018-01-01

    Background The ability to return to work after infective endocarditis (IE) holds important socioeconomic consequences for both patients and society, yet data on this issue are sparse. We examined return to the workforce and associated factors in IE patients of working age. Methods Using Danish...

  20. Husbands' return migration and wives' occupational choices

    NARCIS (Netherlands)

    Mahe, Clotilde

    2017-01-01

    Exploiting the documented effect of migration on occupational choice upon return to their origin country with data from Egypt, we establish a link between return migration of men and their wives' time use through within-couple occupational interdependence. Seemingly Unrelated Regression model

  1. Parasitic diseases in the returning traveller

    African Journals Online (AJOL)

    2009-06-11

    Jun 11, 2009 ... exception is infection with schistosomiasis after leisure activities in infested freshwater. (the water sports enthusiast returning from a sojourn on Lake Malawi .... are harbouring a 'blind passenger' from abroad. However, long-term travellers, both private or business, should be screened on return. A thorough ...

  2. A risk explicit interval linear programming model for uncertainty-based environmental economic optimization in the Lake Fuxian watershed, China.

    Science.gov (United States)

    Zhang, Xiaoling; Huang, Kai; Zou, Rui; Liu, Yong; Yu, Yajuan

    2013-01-01

    The conflict of water environment protection and economic development has brought severe water pollution and restricted the sustainable development in the watershed. A risk explicit interval linear programming (REILP) method was used to solve integrated watershed environmental-economic optimization problem. Interval linear programming (ILP) and REILP models for uncertainty-based environmental economic optimization at the watershed scale were developed for the management of Lake Fuxian watershed, China. Scenario analysis was introduced into model solution process to ensure the practicality and operability of optimization schemes. Decision makers' preferences for risk levels can be expressed through inputting different discrete aspiration level values into the REILP model in three periods under two scenarios. Through balancing the optimal system returns and corresponding system risks, decision makers can develop an efficient industrial restructuring scheme based directly on the window of "low risk and high return efficiency" in the trade-off curve. The representative schemes at the turning points of two scenarios were interpreted and compared to identify a preferable planning alternative, which has the relatively low risks and nearly maximum benefits. This study provides new insights and proposes a tool, which was REILP, for decision makers to develop an effectively environmental economic optimization scheme in integrated watershed management.

  3. A Risk Explicit Interval Linear Programming Model for Uncertainty-Based Environmental Economic Optimization in the Lake Fuxian Watershed, China

    Directory of Open Access Journals (Sweden)

    Xiaoling Zhang

    2013-01-01

    Full Text Available The conflict of water environment protection and economic development has brought severe water pollution and restricted the sustainable development in the watershed. A risk explicit interval linear programming (REILP method was used to solve integrated watershed environmental-economic optimization problem. Interval linear programming (ILP and REILP models for uncertainty-based environmental economic optimization at the watershed scale were developed for the management of Lake Fuxian watershed, China. Scenario analysis was introduced into model solution process to ensure the practicality and operability of optimization schemes. Decision makers’ preferences for risk levels can be expressed through inputting different discrete aspiration level values into the REILP model in three periods under two scenarios. Through balancing the optimal system returns and corresponding system risks, decision makers can develop an efficient industrial restructuring scheme based directly on the window of “low risk and high return efficiency” in the trade-off curve. The representative schemes at the turning points of two scenarios were interpreted and compared to identify a preferable planning alternative, which has the relatively low risks and nearly maximum benefits. This study provides new insights and proposes a tool, which was REILP, for decision makers to develop an effectively environmental economic optimization scheme in integrated watershed management.

  4. Minimum period and the gap in periods of Cataclysmic binaries

    International Nuclear Information System (INIS)

    Paczynski, B.; Sienkiewicz, R.

    1983-01-01

    The 81 minute cutoff to the orbital periods of hydrogen-rich cataclysmic binaries is consistent with evolution of those systems being dominated by angular momentum losses due to gravitational radiation. Unfortunately, many uncertainties, mainly poorly known atmospheric opacities below 2000 K, make is physically impossible to verify the quadrupole formula for gravitational radiation by using the observed cutoff at 81 minutes. The upper boundary of the gap in orbital periods observed at about 3 hours is almost certainly due to enhanced angular momentum losses from cataclysmic binaries which have longer periods. The physical mechanism of those losses is not identified, but a possible importance of stellar winds is pointed out. The lower boundary of the gap may be explained with the oldest cataclysmic binaries, whose periods evolved past the minimum at 81 minutes and reached the value of 2 hours within about 12 x 10 9 years after the binary had formed. Those binaries should have secondary components of only 0.02 solar masses, and their periods could be used to estimate ages of the oldest cataclysmic stars, and presumably the age of Galaxy. An alternative explanation for the gap requires that binaries should be detached while crossing the gap. A possible mechanism for this phenomenon is discussed. It requires the secondary components to be about 0.2 solar masses in the binaries just below the gap

  5. The Risk Return Relationship: Evidence from Index Return and Realised Variance Series

    OpenAIRE

    Minxian Yang

    2014-01-01

    The risk return relationship is analysed in bivariate models for return and realised variance(RV) series. Based on daily time series from 21 international market indices for more than 13 years (January 2000 to February 2013), the empirical findings support the arguments of risk return tradeoff, volatility feedback and statistical balance. It is reasoned that the empirical risk return relationship is primarily shaped by two important data features: the negative contemporaneous correlation betw...

  6. Return currents in solar flares - Collisionless effects

    Science.gov (United States)

    Rowland, H. L.; Vlahos, L.

    1985-01-01

    If the primary, precipitating electrons in a solar flare are unstable to beam plasma interactions, it is shown that strong Langmuir turbulence can seriously modify the way in which a return current is carried by the background plasma. In particular, the return (or reverse) current will not be carried by the bulk of the electrons, but by a small number of high velocity electrons. For beam/plasma densities greater than 0.01, this can reduce the effects of collisions on the return current. For higher density beams where the return current could be unstable to current driven instabilities, the effects of strong turbulence anomalous resistivity is shown to prevent the appearance of such instabilities. Again in this regime, how the return current is carried is determined by the beam generated strong turbulence.

  7. Poetic Return in Afghanistan Persian Poem

    Directory of Open Access Journals (Sweden)

    Esmaeil Shafagh

    2012-11-01

    Full Text Available Abstract Poetic return movement was started by a group of poets like Moshtagh and Shole Esfehani in the second half of 12 century. Their goal was restoring Persian poem and deliverance of Hindi style decline. Esfahan’s poets initiative was considered only in Iran but in other Persian language and literature areas like India, Afghanistan and Transoxiana it was ignored. After the failure of constitutional Movement in Afghanistan, motion similar poetic return was happened that caused poetic themes, which had gone towards modernism, return to Hindi style again.The present paper attempts to analyze the poetic atmosphere in Afghanistan synchronous the poetic return movement in Iran and investigate socio- political backgrounds of return to Hindi style in Afghanistan after constitution failure.

  8. Identification of flow paths and quantification of return flow volumes and timing at field scale

    Science.gov (United States)

    Claes, N.; Paige, G. B.; Parsekian, A.

    2017-12-01

    Flood irrigation, which constitutes a large part of agricultural water use, accounts for a significant amount of the water that is diverted from western streams. Return flow, the portion of the water applied to irrigated areas that returns to the stream, is important for maintaining base flows in streams and ecological function of riparian zones and wetlands hydrologically linked with streams. Prediction of timing and volumes of return flow during and after flood irrigation pose a challenge due to the heterogeneity of pedogenic and soil physical factors that influence vadose zone processes. In this study, we quantify volumes of return flow and potential pathways in the subsurface through a vadose zone flow model that is informed by both hydrological and geophysical observations in a Bayesian setting. We couple a two-dimensional vadose zone flow model through a Bayesian Markov Chain Monte Carlo approach with time lapse ERT, borehole NMR datasets that are collected during and after flood irrigation experiments, and soil physical lab analysis. The combination of both synthetic models and field observations leads to flow path identification and allows for quantification of volumes and timing and associated uncertainties of subsurface return that stems from flood irrigation. The quantification of the impact of soil heterogeneity enables us to translate these results to other sites and predict return flow under different soil physical settings. This is key when managing irrigation water resources and predictions of outcomes of different scenarios have to be evaluated.

  9. On the uncertainty principle. V

    International Nuclear Information System (INIS)

    Halpern, O.

    1976-01-01

    The treatment of ideal experiments connected with the uncertainty principle is continued. The author analyzes successively measurements of momentum and position, and discusses the common reason why the results in all cases differ from the conventional ones. A similar difference exists for the measurement of field strengths. The interpretation given by Weizsaecker, who tried to interpret Bohr's complementarity principle by introducing a multi-valued logic is analyzed. The treatment of the uncertainty principle ΔE Δt is deferred to a later paper as is the interpretation of the method of variation of constants. Every ideal experiment discussed shows various lower limits for the value of the uncertainty product which limits depend on the experimental arrangement and are always (considerably) larger than h. (Auth.)

  10. Davis-Besse uncertainty study

    International Nuclear Information System (INIS)

    Davis, C.B.

    1987-08-01

    The uncertainties of calculations of loss-of-feedwater transients at Davis-Besse Unit 1 were determined to address concerns of the US Nuclear Regulatory Commission relative to the effectiveness of feed and bleed cooling. Davis-Besse Unit 1 is a pressurized water reactor of the raised-loop Babcock and Wilcox design. A detailed, quality-assured RELAP5/MOD2 model of Davis-Besse was developed at the Idaho National Engineering Laboratory. The model was used to perform an analysis of the loss-of-feedwater transient that occurred at Davis-Besse on June 9, 1985. A loss-of-feedwater transient followed by feed and bleed cooling was also calculated. The evaluation of uncertainty was based on the comparisons of calculations and data, comparisons of different calculations of the same transient, sensitivity calculations, and the propagation of the estimated uncertainty in initial and boundary conditions to the final calculated results

  11. Decommissioning Funding: Ethics, Implementation, Uncertainties

    International Nuclear Information System (INIS)

    2007-01-01

    This status report on decommissioning funding: ethics, implementation, uncertainties is based on a review of recent literature and materials presented at NEA meetings in 2003 and 2004, and particularly at a topical session organised in November 2004 on funding issues associated with the decommissioning of nuclear power facilities. The report also draws on the experience of the NEA Working Party on Decommissioning and Dismantling (WPDD). This report offers, in a concise form, an overview of relevant considerations on decommissioning funding mechanisms with regard to ethics, implementation and uncertainties. Underlying ethical principles found in international agreements are identified, and factors influencing the accumulation and management of funds for decommissioning nuclear facilities are discussed together with the main sources of uncertainties of funding systems

  12. Correlated uncertainties in integral data

    International Nuclear Information System (INIS)

    McCracken, A.K.

    1978-01-01

    The use of correlated uncertainties in calculational data is shown in cases investigated to lead to a reduction in the uncertainty of calculated quantities of importance to reactor design. It is stressed however that such reductions are likely to be important in a minority of cases of practical interest. The effect of uncertainties in detector cross-sections is considered and is seen to be, in some cases, of equal importance to that in the data used in calculations. Numerical investigations have been limited by the sparse information available on data correlations; some comparisons made of these data reveal quite large inconsistencies for both detector cross-sections and cross-section of interest for reactor calculations

  13. Uncertainty and Sensitivity Analyses Plan

    International Nuclear Information System (INIS)

    Simpson, J.C.; Ramsdell, J.V. Jr.

    1993-04-01

    Hanford Environmental Dose Reconstruction (HEDR) Project staff are developing mathematical models to be used to estimate the radiation dose that individuals may have received as a result of emissions since 1944 from the US Department of Energy's (DOE) Hanford Site near Richland, Washington. An uncertainty and sensitivity analyses plan is essential to understand and interpret the predictions from these mathematical models. This is especially true in the case of the HEDR models where the values of many parameters are unknown. This plan gives a thorough documentation of the uncertainty and hierarchical sensitivity analysis methods recommended for use on all HEDR mathematical models. The documentation includes both technical definitions and examples. In addition, an extensive demonstration of the uncertainty and sensitivity analysis process is provided using actual results from the Hanford Environmental Dose Reconstruction Integrated Codes (HEDRIC). This demonstration shows how the approaches used in the recommended plan can be adapted for all dose predictions in the HEDR Project

  14. Evaluating bull fertility based on non-return method

    Directory of Open Access Journals (Sweden)

    Prka Igor

    2012-01-01

    Full Text Available In order to evaluate the results of reproductive cows and heifers, different parameters of fertility are used, such as the service period, insemination index, intercalving time and others, and of the breeding bulls the values obtained through non-return. An ejaculate is taken up for further processing by veterinary centres only provided it meets the prescribed quality parameters. Rating semen parameters includes a macroscopic (volume, colour, consistency, smell and pH and a microscopic evaluation (mobility, density, percentage of live sperm and abnormal and damaged sperm. In addition to sperm quality and the fertility of the female animal, the results of the non-return method are also influenced by a number of exogenous causes (season, age, race, insemination techniques that have no small impact on the end result of insemination - pregnancy. In order to obtain more objective results of the fertility of bulls the following tasks were undertaken, namely: 1. to calculate with the non-return method the fertility of bulls in over 10,000 cows inseminated for the first time during a period of 6 years; and 2. to analyze the impact of semen quality, season, age of cow and bull, and the bull breed on the results of fertility.

  15. 75 FR 76940 - Specified Tax Return Preparers Required To File Individual Income Tax Returns Using Magnetic...

    Science.gov (United States)

    2010-12-10

    ... DEPARTMENT OF THE TREASURY Internal Revenue Service 26 CFR Parts 1 and 301 [REG-100194-10] RIN 1545-BJ52 Specified Tax Return Preparers Required To File Individual Income Tax Returns Using Magnetic... for ``specified tax return prepares,''. FOR FURTHER INFORMATION CONTACT: Keith L. Brau at (202) 622...

  16. Uncertainty, financial development and economic growth : an empirical analysis

    NARCIS (Netherlands)

    Lensink, Robert

    1999-01-01

    This paper examines whether financial sector development may partly undo growth-reducing effects of policy uncertainty. By performing a cross-country growth regression for the 1970-1995 period I find evidence that countries with a more developed financial sector are better able to nullify the

  17. Scenario tree airline fleet planning for demand uncertainty

    NARCIS (Netherlands)

    Repko, M.G.J.; Lopes dos Santos, Bruno F.

    2017-01-01

    This paper proposes an innovative multi-period modeling approach to solve the airline fleet planning problem under demand uncertainty. The problem is modeled using a scenario tree approach. The tree is composed of nodes, which represent points of decision in multiple time stages of the planning

  18. The Years of Uncertainty: Eighth Grade Family Life Education.

    Science.gov (United States)

    Carson, Mary, Ed.; And Others

    The family life sex education unit for eighth graders, "The Years of Uncertainty," consists of a series of daily lesson plans that span a 29-day period of one-hour class sessions. Topics covered are: problem solving, knowledge and attitudes, male and female reproductive systems, conception, pregnancy, birth, birth defects, venereal…

  19. Summary of existing uncertainty methods

    International Nuclear Information System (INIS)

    Glaeser, Horst

    2013-01-01

    A summary of existing and most used uncertainty methods is presented, and the main features are compared. One of these methods is the order statistics method based on Wilks' formula. It is applied in safety research as well as in licensing. This method has been first proposed by GRS for use in deterministic safety analysis, and is now used by many organisations world-wide. Its advantage is that the number of potential uncertain input and output parameters is not limited to a small number. Such a limitation was necessary for the first demonstration of the Code Scaling Applicability Uncertainty Method (CSAU) by the United States Regulatory Commission (USNRC). They did not apply Wilks' formula in their statistical method propagating input uncertainties to obtain the uncertainty of a single output variable, like peak cladding temperature. A Phenomena Identification and Ranking Table (PIRT) was set up in order to limit the number of uncertain input parameters, and consequently, the number of calculations to be performed. Another purpose of such a PIRT process is to identify the most important physical phenomena which a computer code should be suitable to calculate. The validation of the code should be focused on the identified phenomena. Response surfaces are used in some applications replacing the computer code for performing a high number of calculations. The second well known uncertainty method is the Uncertainty Methodology Based on Accuracy Extrapolation (UMAE) and the follow-up method 'Code with the Capability of Internal Assessment of Uncertainty (CIAU)' developed by the University Pisa. Unlike the statistical approaches, the CIAU does compare experimental data with calculation results. It does not consider uncertain input parameters. Therefore, the CIAU is highly dependent on the experimental database. The accuracy gained from the comparison between experimental data and calculated results are extrapolated to obtain the uncertainty of the system code predictions

  20. Awe, uncertainty, and agency detection.

    Science.gov (United States)

    Valdesolo, Piercarlo; Graham, Jesse

    2014-01-01

    Across five studies, we found that awe increases both supernatural belief (Studies 1, 2, and 5) and intentional-pattern perception (Studies 3 and 4)-two phenomena that have been linked to agency detection, or the tendency to interpret events as the consequence of intentional and purpose-driven agents. Effects were both directly and conceptually replicated, and mediational analyses revealed that these effects were driven by the influence of awe on tolerance for uncertainty. Experiences of awe decreased tolerance for uncertainty, which, in turn, increased the tendency to believe in nonhuman agents and to perceive human agency in random events.