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. 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.

  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. 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.

  5. 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

  6. 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

  7. 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.

  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. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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)

  15. 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...

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  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. 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.

  5. 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.

  6. 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.

  7. 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 ...

  8. 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...

  9. 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

  10. 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.

  11. 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

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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.…

  17. 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

  18. 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

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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...

  7. 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)

  8. 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.

  9. 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.

  10. 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,

  11. 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.

  12. 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…

  13. 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)

  14. 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 .

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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...

  1. 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.

  2. 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.

  3. 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.

  4. Maximum-likelihood fitting of data dominated by Poisson statistical uncertainties

    International Nuclear Information System (INIS)

    Stoneking, M.R.; Den Hartog, D.J.

    1996-06-01

    The fitting of data by χ 2 -minimization is valid only when the uncertainties in the data are normally distributed. When analyzing spectroscopic or particle counting data at very low signal level (e.g., a Thomson scattering diagnostic), the uncertainties are distributed with a Poisson distribution. The authors have developed a maximum-likelihood method for fitting data that correctly treats the Poisson statistical character of the uncertainties. This method maximizes the total probability that the observed data are drawn from the assumed fit function using the Poisson probability function to determine the probability for each data point. The algorithm also returns uncertainty estimates for the fit parameters. They compare this method with a χ 2 -minimization routine applied to both simulated and real data. Differences in the returned fits are greater at low signal level (less than ∼20 counts per measurement). the maximum-likelihood method is found to be more accurate and robust, returning a narrower distribution of values for the fit parameters with fewer outliers

  5. 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

  6. 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

  7. 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...

  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. 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. 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.

  11. 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.

  12. 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.)

  13. 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

  14. 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.

  15. 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)

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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....

  1. 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

  2. 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

  3. 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

  4. 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)

  5. 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.

  6. 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

  7. Government policy uncertainty and stock prices: The case of Australia's uranium industry

    International Nuclear Information System (INIS)

    Ferguson, Andrew; Lam, Peter

    2016-01-01

    We investigate effects of government policy uncertainty on stock prices, reflecting tension between ‘private interest’ (economic benefits) and ‘public interest’ arguments over uranium mining. Using a sample of Australian-listed uranium firms from January 2005 through June 2008, we document a positive contemporaneous correlation between stock returns and volatility and two measures of government policy uncertainty, proxied by the spread in voters' opinion polls between the two major political parties and a news-based sentiment index. Event-study results show significant stock price reactions to key uranium-related policy events, with cross-sectional variation in event returns predicted by models incorporating firm- and project-level characteristics. Our research design and findings may inform future research on the capital market effects of government policy uncertainty in other regulated industries. - Highlights: • Government policy uncertainty has direct effects on stock prices of uranium explorers. • Stock returns are positively related to the spread in two-party-preferred voting intention. • Stock volatility is positively related to a uranium news-based sentiment index. • Event-study results show significant market reaction to key uranium policy events.

  8. 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...

  9. 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

  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. 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.

  12. 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...

  13. 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)

  14. 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.

  15. 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...

  16. 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...

  17. 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.

  18. 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

  19. 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

  20. 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.

  1. 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.

  2. 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...

  3. 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.

  4. Simulating return signals of a spaceborne high-spectral resolution lidar channel at 532 nm

    Science.gov (United States)

    Xiao, Yu; Binglong, Chen; Min, Min; Xingying, Zhang; Lilin, Yao; Yiming, Zhao; Lidong, Wang; Fu, Wang; Xiaobo, Deng

    2018-06-01

    High spectral resolution lidar (HSRL) system employs a narrow spectral filter to separate the particulate (cloud/aerosol) and molecular scattering components in lidar return signals, which improves the quality of the retrieved cloud/aerosol optical properties. To better develop a future spaceborne HSRL system, a novel simulation technique was developed to simulate spaceborne HSRL return signals at 532 nm using the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) cloud/aerosol extinction coefficients product and numerical weather prediction data. For validating simulated data, a mathematical particulate extinction coefficient retrieval method for spaceborne HSRL return signals is described here. We compare particulate extinction coefficient profiles from the CALIPSO operational product with simulated spaceborne HSRL data. Further uncertainty analysis shows that relative uncertainties are acceptable for retrieving the optical properties of cloud and aerosol. The final results demonstrate that they agree well with each other. It indicates that the return signals of the spaceborne HSRL molecular channel at 532 nm will be suitable for developing operational algorithms supporting a future spaceborne HSRL system.

  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. 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

  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. 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

  9. 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...

  10. 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...

  11. 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.

  12. 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.

  13. 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.

  14. 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...

  15. 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...

  16. 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.

  17. 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...

  18. 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.

  19. 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....

  20. 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

  1. 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...

  2. 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.

  3. 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.

  4. 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...

  5. 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...

  6. 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

  7. 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

  8. 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.

  9. 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....

  10. 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...

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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)

  16. 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.

  17. 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.

  18. 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...

  19. 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.

  20. Achieving Robustness to Uncertainty for Financial Decision-making

    Energy Technology Data Exchange (ETDEWEB)

    Barnum, George M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Van Buren, Kendra L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hemez, Francois M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Song, Peter [Univ. of Pennsylvania, Philadelphia, PA (United States)

    2014-01-10

    This report investigates the concept of robustness analysis to support financial decision-making. Financial models, that forecast future stock returns or market conditions, depend on assumptions that might be unwarranted and variables that might exhibit large fluctuations from their last-known values. The analysis of robustness explores these sources of uncertainty, and recommends model settings such that the forecasts used for decision-making are as insensitive as possible to the uncertainty. A proof-of-concept is presented with the Capital Asset Pricing Model. The robustness of model predictions is assessed using info-gap decision theory. Info-gaps are models of uncertainty that express the “distance,” or gap of information, between what is known and what needs to be known in order to support the decision. The analysis yields a description of worst-case stock returns as a function of increasing gaps in our knowledge. The analyst can then decide on the best course of action by trading-off worst-case performance with “risk”, which is how much uncertainty they think needs to be accommodated in the future. The report also discusses the Graphical User Interface, developed using the MATLAB® programming environment, such that the user can control the analysis through an easy-to-navigate interface. Three directions of future work are identified to enhance the present software. First, the code should be re-written using the Python scientific programming software. This change will achieve greater cross-platform compatibility, better portability, allow for a more professional appearance, and render it independent from a commercial license, which MATLAB® requires. Second, a capability should be developed to allow users to quickly implement and analyze their own models. This will facilitate application of the software to the evaluation of proprietary financial models. The third enhancement proposed is to add the ability to evaluate multiple models simultaneously

  1. 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.

  2. 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)

  3. 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.

  4. Estimating the Accuracy of the Return on Investment (ROI Performance Evaluations

    Directory of Open Access Journals (Sweden)

    Alexei Botchkarev

    2015-12-01

    Full Text Available Return on Investment (ROI is one of the most popular performance measurement and evaluation metrics. ROI analysis (when applied correctly is a powerful tool in comparing solutions and making informed decisions on the acquisitions of information systems. The purpose of this study is to provide a systematic research of the accuracy of the ROI evaluations in the context of information systems implementations. Measurements theory and error analysis, specifically propagation of uncertainties methods, were used to derive analytical expressions for ROI errors. Monte Carlo simulation methodology was used to design and deliver a quantitative experiment to model costs and returns estimating errors and calculate ROI accuracies. Spreadsheet simulation (Microsoft Excel spreadsheets enhanced with Visual Basic for Applications was used to implement Monte Carlo simulations. The main contribution of the study is that this is the first systematic effort to evaluate ROI accuracy. Analytical expressions have been derived for estimating errors of the ROI evaluations. Results of the Monte Carlo simulation will help practitioners in making informed decisions based on explicitly stated factors influencing the ROI uncertainties.

  5. 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.

  6. 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

  7. 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...

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. Investment in risky R and D programs in the face of climate uncertainty

    International Nuclear Information System (INIS)

    Baker, Erin; Adu-Bonnah, Kwame

    2008-01-01

    We analyze how the socially optimal technology R and D investment changes with the risk-profile of the R and D program and with uncertainty about climate damages. We show that how technology is represented in the model is crucial to the results; and that uncertainty in damages interacts with uncertainty in the returns to R and D. We consider R and D that reduces the cost of abatement multiplicatively, and argue that this is a good representation of R and D into non-carbon technologies; and R and D that reduces the emissions-to-output ratio, and argue that this is a good representation of R and D into fossil fuel technologies. For R and D programs into non-carbon technologies, optimal investment is higher in riskier programs. Our empirical model indicates that the optimal investment in a risky program is about 3 1/2 times larger than in a program with certain returns. For R and D programs aimed at reducing emissions in fossil fuel based technologies, our results show that, qualitatively, investment is higher in less risky programs under most uncertain damage scenarios. Our empirical model shows, however, that the risk-profile of fossil fuel based R and D programs generally has little quantitative impact on optimal investment. The exception is that when the probability of a catastrophe inducing full abatement is very high, investment is about twice as high in risky programs compared to programs with certain returns. (author)

  18. Quantifying the uncertainty of wave energy conversion device cost for policy appraisal: An Irish case study

    International Nuclear Information System (INIS)

    Farrell, Niall; Donoghue, Cathal O’; Morrissey, Karyn

    2015-01-01

    Wave Energy Conversion (WEC) devices are at a pre-commercial stage of development with feasibility studies sensitive to uncertainties surrounding assumed input costs. This may affect decision making. This paper analyses the impact these uncertainties may have on investor, developer and policymaker decisions using an Irish case study. Calibrated to data present in the literature, a probabilistic methodology is shown to be an effective means to carry this out. Value at Risk (VaR) and Conditional Value at Risk (CVaR) metrics are used to quantify the certainty of achieving a given cost or return on investment. We analyse the certainty of financial return provided by the proposed Irish Feed-in Tariff (FiT) policy. The influence of cost reduction through bulk discount is also discussed, with cost reduction targets for developers identified. Uncertainty is found to have a greater impact on the profitability of smaller installations and those subject to lower rates of cost reduction. This paper emphasises that a premium is required to account for cost uncertainty when setting FiT rates. By quantifying uncertainty, a means to specify an efficient premium is presented. - Highlights: • Probabilistic model quantifies uncertainty for wave energy feasibility analyses. • Methodology presented and applied to an Irish case study. • A feed-in tariff premium of 3–4 c/kWh required to account for cost uncertainty. • Sensitivity of uncertainty and cost to rates of technological change analysed. • Use of probabilistic model for investors and developers also demonstrated

  19. 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...

  20. 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

  1. 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 ...

  2. 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.

  3. 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...

  4. 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.

  5. 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…

  6. The returns and risks of investment portfolio in a financial market

    Science.gov (United States)

    Li, Jiang-Cheng; Mei, Dong-Cheng

    2014-07-01

    The returns and risks of investment portfolio in a financial system was investigated by constructing a theoretical model based on the Heston model. After the theoretical model and analysis of portfolio were calculated and analyzed, we find the following: (i) The statistical properties (i.e., the probability distribution, the variance and loss rate of equity portfolio return) between simulation results of the theoretical model and the real financial data obtained from Dow Jones Industrial Average are in good agreement; (ii) The maximum dispersion of the investment portfolio is associated with the maximum stability of the equity portfolio return and minimal investment risks; (iii) An increase of the investment period and a worst investment period are associated with a decrease of stability of the equity portfolio return and a maximum investment risk, respectively.

  7. 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...

  8. Transposing an active fault database into a fault-based seismic hazard assessment for nuclear facilities - Part 2: Impact of fault parameter uncertainties on a site-specific PSHA exercise in the Upper Rhine Graben, eastern France

    Science.gov (United States)

    Chartier, Thomas; Scotti, Oona; Clément, Christophe; Jomard, Hervé; Baize, Stéphane

    2017-09-01

    We perform a fault-based probabilistic seismic hazard assessment (PSHA) exercise in the Upper Rhine Graben to quantify the relative influence of fault parameters on the hazard at the Fessenheim nuclear power plant site. Specifically, we show that the potentially active faults described in the companion paper (Jomard et al., 2017, hereafter Part 1) are the dominant factor in hazard estimates at the low annual probability of exceedance relevant for the safety assessment of nuclear installations. Geological information documenting the activity of the faults in this region, however, remains sparse, controversial and affected by a high degree of uncertainty. A logic tree approach is thus implemented to explore the epistemic uncertainty and quantify its impact on the seismic hazard estimates. Disaggregation of the peak ground acceleration (PGA) hazard at a 10 000-year return period shows that the Rhine River fault is the main seismic source controlling the hazard level at the site. Sensitivity tests show that the uncertainty on the slip rate of the Rhine River fault is the dominant factor controlling the variability of the seismic hazard level, greater than the epistemic uncertainty due to ground motion prediction equations (GMPEs). Uncertainty on slip rate estimates from 0.04 to 0.1 mm yr-1 results in a 40 to 50 % increase in hazard levels at the 10 000-year target return period. Reducing epistemic uncertainty in future fault-based PSHA studies at this site will thus require (1) performing in-depth field studies to better characterize the seismic potential of the Rhine River fault; (2) complementing GMPEs with more physics-based modelling approaches to better account for the near-field effects of ground motion and (3) improving the modelling of the background seismicity. Indeed, in this exercise, we assume that background earthquakes can only host M 6. 0 earthquakes have been recently identified at depth within the Upper Rhine Graben (see Part 1) but are not accounted

  9. 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....

  10. 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.

  11. Characteristics of Criteria for Selecting Investment Projects under Uncertainty

    Directory of Open Access Journals (Sweden)

    Adrian ENCIU

    2011-07-01

    Full Text Available Within financial theory and practice, there are used five main criteria for selecting investment projects: the net present value (NPV criterion, the internal rate of return (IRR criterion, the return term (RT criterion, the profitability ratio (PR criterion and the supplementary return (SR criterion. The assay will emphasize several new properties of said indexes for investment assessment, having as starting point the hypotheses of (approximately normal repartition of cash-flows generated by an investment project. The obtained results point to the fact that the NPV indexes (the analysis of this criterion was carried out in the article “The NPV Criterion for Valuing Investments under Uncertainty”, Daniel Armeanu, Leonard Lache, Economic Computation and Economic Cybernetics Studies and Research no. 4/2009, pp. 133-143, IRR, PR, RT and SR register normal repartitions, therefore simplifying the investment analysis under economic uncertainty, by the capacity of building confidence intervals and assessing probabilities for the inferior limits of said investment assessment indexes.

  12. 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.

  13. 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

  14. ANALISIS FAKTOR-FAKTOR YANG MEMPENGARUHI RETURN SAHAM KONSTRUKSI BUMN DENGAN REGRESI PANEL DINAMIS

    Directory of Open Access Journals (Sweden)

    Al Muizzuddin Fazaalloh

    2016-03-01

    Full Text Available This study aims to determine the factors that affect stock returns in the Indonesian state-owned construction period January 2013 to December 2015. The variables used were trading volume, market capitalization, inflation, exchange rate and government policy. The data in this research is secondary data obtained from the publication of the Central Bureau of Statistics, Ministry of Commerce and the Indonesia Stock Exchange. This study uses a dynamic panel regression by the method of Generalized Method of Moments (GMM. The results showed that lagged stock returns, trading volume at this time and the exchange rate at the moment significant negative effect on stock returns. While the market capitalization in the current and prior periods and inflation at the moment and the two previous period significant positive effect on stock returns. Besides the government's policy affect to state-owned construction stock returns where policies are made in the era of President Joko Widodo more influence smaller than the policy made during the leadership of President Susilo Bambang Yudhoyono.

  15. 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.

  16. 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

  17. 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...

  18. 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)

  19. Weather effects on the returns and volatility of the Shanghai stock market

    Science.gov (United States)

    Kang, Sang Hoon; Jiang, Zhuhua; Lee, Yeonjeong; Yoon, Seong-Min

    2010-01-01

    This study investigates the weather effects on returns as well as volatility in the Shanghai stock market. In order to analyze the influence of the opening of B-share market to domestic investors, it is assumed that domestic investors are more sensitive to the Shanghai local weather than foreign investors. In doing so, extreme weather condition dummies are generated by using the 21-day and 31-day moving average and its standard deviation. Empirical analysis provides two key results regarding weather effects. First, the weather effect exists in the A-share returns, but does not exist in the B-share returns over the whole period. In addition, the post-opening period shows the strong weather effect on B-share returns only, indicating that the market openness to domestic investors results in the weather effect. Second, the weather effect has a strong influence on the volatility of both A- and B-share returns. Similar to the case of returns, the weather effect on volatility is explained by the openness of B-share market.

  20. 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 ...

  1. 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

  2. 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.

  3. Adoption of residential solar power under uncertainty: Implications for renewable energy incentives

    International Nuclear Information System (INIS)

    Bauner, Christoph; Crago, Christine L.

    2015-01-01

    Many incentives at the state and federal level exist for household adoption of renewable energy like solar photovoltaic (PV) panels. Despite generous financial incentives the adoption rate is low. We use the option value framework, which takes into account the benefit of delaying investment in response to uncertainty, to examine the decision by households to invest in solar PV. Using a simulation model, we determine optimal adoption times, critical values of discounted benefits, and adoption rates over time for solar PV investments using data from Massachusetts. We find that the option value multiplier is 1.6, which implies that the discounted value of benefits from solar PV needs to exceed installation cost by 60% for investment to occur. Without any policies, median adoption time is eight years longer under the option value decision rule compared to the net present value decision rule where households equate discounted benefits to installation cost. Rebates and other financial incentives decrease adoption time, but their effect is attenuated if households apply the option value decision rule to solar PV investments. Results suggest that policies that reduce the uncertainty in returns from solar PV investments would be most effective at incentivizing adoption. - Highlights: • We examine household adoption of solar PV using the option value framework. • Uncertainty in benefits and costs leads to delay in investment timing. • Discounted benefits from solar PV have to exceed investment cost by 60% to trigger investment. • Policy incentives that reduce uncertainty in returns from solar PV are most effective.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. Price Earnings Ratio and Stock Return Analysis (Evidence from Liquidity 45 Stocks Listed in Indonesia Stock Exchange

    Directory of Open Access Journals (Sweden)

    Liem Pei Fun

    2012-01-01

    Full Text Available Price to Earnings Ratio (PE Ratio has been broadly used by analysts and investors for stock selection. Stocks with low PE ratio are perceived as having cheaper current price hence expected to generate higher return in subsequent period. This paper aims to examine predictability of stock return using PE Ratio based on historical relationship between PE Ratio and subsequent stock return. Particularly, it seeks to find whether stocks with high PE Ratio followed by low stocks return and on the contrary, stocks with low PE Ratio followed by high stocks return. Using stocks which are included as member of Liquidity 45 and observation period 2005-2010 as samples, results show that there is significance difference between low PE and high PE portfolio stock return in short term (holding period of 6 months but there is no significance difference between both portfolio stock return if they are hold for one, two, three, and four years. This research also finds that there is no significant relationship between stock return and (trailing PE Ratio which suggests that (trailing PE Ratio is not useful in estimating both short term and long term stock returns

  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.

    2013-11-01

    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.

  11. 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.

  12. 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)

  13. 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

  14. 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...

  15. Effect of uncertainty in Digital Surface Models on the boundary of inundated areas

    Science.gov (United States)

    Nalbantis, I.; Papageorgaki, I.; Sioras, P.; Ioannidis, Ch.

    2012-04-01

    The planning, design and operation of flood damage reduction works or non-structural measures require the construction of maps that indicate zones to be potentially inundated during floods. Referring to floods due to heavy rainfall, the common procedure for flood mapping consists of the following five computational steps: (1) Frequency analysis of extreme rainfall; (2) construction of design hyetographs for various return periods; (3) construction of the related direct runoff hydrographs; (4) routing of these hydrographs through the hydrographic network; (5) mapping of the inundated area that corresponds to the temporally maximum depth for each location in the flood plain. Steps 3 through 5 require the use of spatial information which can be easily obtained from a Digital Surface Model (DSM). The DSM contains grid-based elevations of the ground or overlying objects that influence the propagation of flood waves. In this work, the SCS-CN method is used in step 3 in combination with a synthetic Unit Hydrograph based on the SCS dimensionless Unit Hydrograph. In step 4, the full one-dimensional Saint Venant equations for non-uniform unsteady flow on fixed bed are used, which are numerically solved. The impact of uncertainty in the DSM on the inundated area boundary is investigated. For this the Monte Carlo simulation method is employed to produce a large number of erroneous DSMs through introducing errors in elevation with a standard deviation equal to σ. These DSMs are then used for delineating potentially flooded areas. The standard deviation of the distance (from the riverbed axis) of the boundary of these areas, herein denoted as σF, is used as the measure of the resulting uncertainty. The link between σ and σF is examined for a spectrum of large return periods (100 to 10000). A computer experiment was set up based on data from two drainage basins. The first basin is located in East Attica and is drained by a branch of the Erasinos Torrent named the South

  16. 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)

  17. Sensitivity Analysis of Expected Wind Extremes over the Northwestern Sahara and High Atlas Region.

    Science.gov (United States)

    Garcia-Bustamante, E.; González-Rouco, F. J.; Navarro, J.

    2017-12-01

    A robust statistical framework in the scientific literature allows for the estimation of probabilities of occurrence of severe wind speeds and wind gusts, but does not prevent however from large uncertainties associated with the particular numerical estimates. An analysis of such uncertainties is thus required. A large portion of this uncertainty arises from the fact that historical observations are inherently shorter that the timescales of interest for the analysis of return periods. Additional uncertainties stem from the different choices of probability distributions and other aspects related to methodological issues or physical processes involved. The present study is focused on historical observations over the Ouarzazate Valley (Morocco) and in a high-resolution regional simulation of the wind in the area of interest. The aim is to provide extreme wind speed and wind gust return values and confidence ranges based on a systematic sampling of the uncertainty space for return periods up to 120 years.

  18. RASIO KEUANGAN PENGUKUR KINERJA PERUSAHAAN DAN DAMPAKNYA TERHADAP EKSPEKTASI RETURN SAHAM

    Directory of Open Access Journals (Sweden)

    Yarnest Yarnest

    2017-03-01

    Full Text Available This research was intended to know and to describe BUMN firm performance listed at Indonesian Stock Exchange.It measured finance ratios and its impact to expectation return good stock partially and simultaneously.This observational object was corporate BUMN listed at Indonesian Stock Exchange, period 2005-2009. Thisresearch used design ex post facto. Exhaustive observational corporate BUMN listed at Indonesian Stock Exchange(BEI were 13 firms. Because of little population, the method used was census method. Analysis techniquesused were analysis multiple regression, quiz f and quiz t, data processing by programs Aviews version 6.0. Theresult of observation showed that liquidity ratio, leverage ratio, activity ratio, profitability ratio and stock ratiocould measure simultaneous firm and performance impacted significant to expectation return stock. Activityratio consisted of average collection period and inventory turnover and stock ratio consisted of price earning ratioand book value per share partially impacted significant to expectation return stock. Meanwhile ratio was liquidity,leverage ratio. Profitability ratio partially did not impact significantly to expectation return stock. Stock ratiomeasured by book value per share constituting impacted as the dominant factor on exspectation return stock.

  19. 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.

  20. 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

  1. Fluctuating Epistemic Uncertainty in a Design Team as a Metacognitive Driver for Creative Cognitive Processes

    DEFF Research Database (Denmark)

    Christensen, Bo; Ball, Linden J.

    2016-01-01

    Previous design research has demonstrated how epistemic uncertainty engenders localized, creative reasoning, including analogizing and mental simulation. Our analysis of the DTRS11 dataset examined not just the short-term, localized effects of epistemic uncertainty on creative processing...... and information selection, but also its long-term impact on downstream creative processes and decisions about what information to take forward. Our hypothesis was that heightened levels of uncertainty associated with a particular cognitive referent (i.e., a post-it note translated from Chinese end-users) would......, as predicted, found to engender subsequent attentive returns to cognitive referents at later points in the design process. Third, although epistemic uncertainty did not predict the information that was eventually selected to take forward in the design space, both immediate creative elaboration and subsequent...

  2. 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.

  3. 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.

  4. 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...

  5. 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

  6. How uncertainty in socio-economic variables affects large-scale transport model forecasts

    DEFF Research Database (Denmark)

    Manzo, Stefano; Nielsen, Otto Anker; Prato, Carlo Giacomo

    2015-01-01

    A strategic task assigned to large-scale transport models is to forecast the demand for transport over long periods of time to assess transport projects. However, by modelling complex systems transport models have an inherent uncertainty which increases over time. As a consequence, the longer...... the period forecasted the less reliable is the forecasted model output. Describing uncertainty propagation patterns over time is therefore important in order to provide complete information to the decision makers. Among the existing literature only few studies analyze uncertainty propagation patterns over...

  7. 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.

  8. 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.

  9. 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.

  10. 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..

  11. 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

  12. Implementing a collaborative return-to-work program: Lessons from a qualitative study in a large Canadian healthcare organization.

    Science.gov (United States)

    Skivington, Kathryn; Lifshen, Marni; Mustard, Cameron

    2016-11-22

    Comprehensive workplace return-to-work policies, applied with consistency, can reduce length of time out of work and the risk of long-term disability. This paper reports on the findings from a qualitative study exploring managers' and return-to-work-coordinators' views on the implementation of their organization's new return-to-work program. To provide practical guidance to organizations in designing and implementing return-to-work programs for their employees. Semi-structured qualitative interviews were undertaken with 20 managers and 10 return-to-work co-ordinators to describe participants' perspectives on the progress of program implementation in the first 18 months of adoption. The study was based in a large healthcare organization in Ontario, Canada. Thematic analysis of the data was conducted. We identified tensions evident in the early implementation phase of the organization's return-to-work program. These tensions were attributed to uncertainties concerning roles and responsibilities and to circumstances where objectives or principles appeared to be in conflict. The implementation of a comprehensive and collaborative return-to-work program is a complex challenge. The findings described in this paper may provide helpful guidance for organizations embarking on the development and implementation of a return-to-work program.

  13. Strategic design of cost savings guarantee in energy performance contracting under uncertainty

    International Nuclear Information System (INIS)

    Deng, Qianli; Jiang, Xianglin; Cui, Qingbin; Zhang, Limao

    2015-01-01

    Highlights: • A methodology is proposed to assist Energy Service Companies to maintain competitiveness in winning bids. • Uncertainties within the energy cost savings are modeled stochastically using the Monte-Carlo simulation. • A strategic energy savings guarantee design curve is derived, where all points return as appropriate guarantees. • A campus case is presented to demonstrate the applicability for finding appropriate guaranteed savings value. - Abstract: Among the key barriers to profit in Energy Performance Contracting (EPC) are uncertainties about attaining the realized energy cost savings and potential disputes over the guaranteed cost savings. In this paper, a methodology has been proposed to assist the Energy Service Company (ESCO): (1) to evaluate the risk threshold if the guarantee has already been made, and (2) to determine the guarantee design, if the guarantee has not been made yet, that not only promises the ESCO’s profitability from EPC but also maintains its competitiveness to win the bid. Uncertainties within the energy cost savings are modeled stochastically using Monte-Carlo simulation, taking both the energy price fluctuation and the facility performance variability into account. Based on that, a strategic energy savings guarantee design curve is derived, that all the points on it would return as appropriate guarantees. Finally, a campus case is presented to demonstrate the applicability for finding the appropriate guaranteed savings value. This method is also worth popularizing in similar performance-based projects

  14. 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)

  15. 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)

  16. 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.

  17. The Relationship Between Economic Growth and Stock Returns : Evidence From Turkey

    Directory of Open Access Journals (Sweden)

    Mehmet ŞENTÜRK

    2014-12-01

    Full Text Available Financial development is one of the most important determinants of the economic development. Financial developments in Turkey began in the early 1980s and still have continued. During this period, it has survived a severe interaction between financial development and economic growth. In this study, the causality relationship between stock returns and economic growth in Turkey it was analysed over the period 1998Q2-2014Q2. In this context; firstly, Bootstrapped Toda-Yamamoto and Frequency Domain causality tests were applied in order to understand the causality relationship between the two variables. As a result of the Bootstrapped Toda-Yamamoto causality test results, there is no relation of causality between the variables, but according to Frequency Domain causality test stock returns cause the economic growth in short term and economic growth cause stock returns in medium term.

  18. Bifurcation Analysis with Aerodynamic-Structure Uncertainties by the Nonintrusive PCE Method

    Directory of Open Access Journals (Sweden)

    Linpeng Wang

    2017-01-01

    Full Text Available An aeroelastic model for airfoil with a third-order stiffness in both pitch and plunge degree of freedom (DOF and the modified Leishman–Beddoes (LB model were built and validated. The nonintrusive polynomial chaos expansion (PCE based on tensor product is applied to quantify the uncertainty of aerodynamic and structure parameters on the aerodynamic force and aeroelastic behavior. The uncertain limit cycle oscillation (LCO and bifurcation are simulated in the time domain with the stochastic PCE method. Bifurcation diagrams with uncertainties were quantified. The Monte Carlo simulation (MCS is also applied for comparison. From the current work, it can be concluded that the nonintrusive polynomial chaos expansion can give an acceptable accuracy and have a much higher calculation efficiency than MCS. For aerodynamic model, uncertainties of aerodynamic parameters affect the aerodynamic force significantly at the stage from separation to stall at upstroke and at the stage from stall to reattach at return. For aeroelastic model, both uncertainties of aerodynamic parameters and structure parameters impact bifurcation position. Structure uncertainty of parameters is more sensitive for bifurcation. When the nonlinear stall flutter and bifurcation are concerned, more attention should be paid to the separation process of aerodynamics and parameters about pitch DOF in structure.

  19. River water quality management considering agricultural return flows: application of a nonlinear two-stage stochastic fuzzy programming.

    Science.gov (United States)

    Tavakoli, Ali; Nikoo, Mohammad Reza; Kerachian, Reza; Soltani, Maryam

    2015-04-01

    In this paper, a new fuzzy methodology is developed to optimize water and waste load allocation (WWLA) in rivers under uncertainty. An interactive two-stage stochastic fuzzy programming (ITSFP) method is utilized to handle parameter uncertainties, which are expressed as fuzzy boundary intervals. An iterative linear programming (ILP) is also used for solving the nonlinear optimization model. To accurately consider the impacts of the water and waste load allocation strategies on the river water quality, a calibrated QUAL2Kw model is linked with the WWLA optimization model. The soil, water, atmosphere, and plant (SWAP) simulation model is utilized to determine the quantity and quality of each agricultural return flow. To control pollution loads of agricultural networks, it is assumed that a part of each agricultural return flow can be diverted to an evaporation pond and also another part of it can be stored in a detention pond. In detention ponds, contaminated water is exposed to solar radiation for disinfecting pathogens. Results of applying the proposed methodology to the Dez River system in the southwestern region of Iran illustrate its effectiveness and applicability for water and waste load allocation in rivers. In the planning phase, this methodology can be used for estimating the capacities of return flow diversion system and evaporation and detention ponds.

  20. 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.

  1. 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...

  2. ANALISIS REAKSI INVESTOR TERHADAP PENGUMUMAN RIGHT ISSUE DI BURSA EFEK JAKARTA (Suatu Pengamatan pada Return, Abnormal Return, Aktivitas Volume Perdagangan dan Bid-Ask Spread Saham

    Directory of Open Access Journals (Sweden)

    SRI DEWI YUSUF

    2012-05-01

    Full Text Available ABSTRACT Development of stock market activity, which grows very fast lead to significant changes on the demand of information quality. To make the rational investor decision making, it is needed a relevant information in order to identify any work of the company. Event study is a study which analyze any market reactions toward an event which the information is published as announcement. Right issue announcement can affect market, it is depent on the existence of the content of the information in the right issue announcement above. If the right issue announcement contains some information so the market will react and the market won’t react if no information. The research sample is determined by a purposive sampling method, and there are 17 companies which announce right issue between 2000-2003. Statistical experiment used is T-test experiment (paired two samples for means. The Observation period which is done in 11 day, consist of 5 day before, 1 day in the moment, and 5 day after the announce right issue. Results show that there is a significant difference between return and abnormal return in the period of between at the moment, and after the announce right issue. The result in the before-after announce right issue period shows that there is no significant difference. The result in the variable activity of stock’s trade volume shows that there is signification difference in the before-at the moment and after period, but in the result of before-after period show that there is no significant difference there. And the result of bid-ask spread variable shows that there is no significant different in the before-at the moment and after period of announce right issue, but in the before-after period the result shows that there is no significant different there. And the result of bid-ask spread variable shows that there is no significant different in the before-at the moment and after period of announce right issue, but in the before-after period

  3. 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.

  4. 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

  5. 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...

  6. 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.

  7. 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

  8. Re-examining the risk–return relationship in Europe: Linear or non-linear trade-off?

    OpenAIRE

    Salvador, Enrique; Floros, Christos; Arago, Vicent

    2014-01-01

    This paper analyzes the risk–return trade-off in Europe using recent data from 11 European stock markets. After relaxing the linear assumptions in the risk–return relationship by introducing a new approach that considers the current state of the market, we obtain significant evidence for a positive risk–return trade-off for low volatility states. However, this finding is reduced or even non-significant during periods of high volatility. Maintaining the linear assumption over the risk–return t...

  9. 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.

  10. 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...

  11. 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.

  12. 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

  13. 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.

  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. 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.

  16. The structure of occupational health nurses' support for return-to-work to workers with depression.

    Science.gov (United States)

    Hatanaka, Junko

    2016-07-29

    The present study aimed to explore the structure of occupational health nurses' support for return-to-work to workers with depression. Semi-structured interviews were conducted with 10 occupational health nurses who support workers returning to work. Data were analyzed using the Modified Grounded Theory Approach. The qualitatively analyzed data was grouped into 9 categories. The support for return-to-work was divided into 3 periods: (1) the first priority for recovery, (2) preparation for return-to-work, and (3) adaptation to work. There were indirect supports to workers such as "environmental arrangement for medical treatment," "connection," and "support form parties concerned about workers," and direct supports such as "readiness for medical treatment," "overcoming social and psychological problems," and "working life independence. " Direct support was facilitated by "construction of the relationship. " The occupational health nurses' philosophy was to support "profitable return-to-work for both the worker and the employer. " These processes were "support of confidence recovery process " to regain confidence lost through absence from work because of depression and to accomplish a smooth return-to-work. There were problems in each period corresponding to the return-to-work conditions, and occupational health nurses supported the employees in overcoming each problem. Moreover, it was said that cooperation with the parties concerned in the office would greatly influence the success or failure in the return-to-work support, and it was thought that direct supports and indirect supports to employees with respect to adjustment with the parties concerned in the office were necessary. The structure of occupational health nurses' supports was to support the confidence recovery process of workers by indirect and direct support at each period of return-to-work.

  17. PERAN PROFITABILITAS DAN LIKUIDITAS SERTA DIVIDEN PAYOUT RATIO TERHADAP RETURN SAHAM

    Directory of Open Access Journals (Sweden)

    Riawan

    2016-10-01

    Full Text Available This study was conducted to examine the influence of fundamental factors of profitability and liquidity on dividend policy (DPR. And furthermore the influence of profitability, liquidity and dividend policy (DPR to return stock in companies incorporated in the Jakarta Islamic Index listed on the Indonesia Stock Exchange for the period 2010-2013. The sampling technique used in this research is purposive sampling with criteria : (1 It is listed in Indonesia Stock Exchange 2010-2013. (2 It is always seem annual financial statements for the period 2010- 2013. (3 It is always pay dividends. The data required in this study were drawn from the Indonesian Capital Market Directory (ICMD from 2010 to 2013 consisting of 20 companies. Multiple regression analysis of the data. Hypothesis test used the t-statistic at the 5% significance level. The results showed profitability and dividend policy (DPR have a significant effect on stock returns. These results indicate that the performance of the fundamental factors of profitability and dividend payout on stock returns are used by investors to predict stock returns manufacturing companies listed in Indonesia Stock Exchange in2010-2013.

  18. 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

  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. 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.

  1. 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.

  2. 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...

  3. 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.

  4. Uncertainties in model-independent extractions of amplitudes from complete experiments

    International Nuclear Information System (INIS)

    Hoblit, S.; Sandorfi, A.M.; Kamano, H.; Lee, T.-S.H.

    2012-01-01

    A new generation of over-complete experiments is underway, with the goal of performing a high precision extraction of pseudoscalar meson photo-production amplitudes. Such experimentally determined amplitudes can be used both as a test to validate models and as a starting point for an analytic continuation in the complex plane to search for poles. Of crucial importance for both is the level of uncertainty in the extracted multipoles. We have probed these uncertainties by analyses of pseudo-data for KLambda photoproduction, first for the set of 8 observables that have been published for the K + Lambda channel and then for pseudo-data on a complete set of 16 observables with the uncertainties expected from analyses of ongoing CLAS experiments. In fitting multipoles, we have used a combined Monte Carlo sampling of the amplitude space, with gradient minimization, and have found a shallow X 2 valley pitted with a large number of local minima. This results in bands of solutions that are experimentally indistinguishable. All ongoing experiments will measure observables with limited statistics. We have found a dependence on the particular random choice of values of Gaussian distributed pseudo-data, due to the presence of multiple local minima. This results in actual uncertainties for reconstructed multipoles that are often considerable larger than those returned by gradient minimization routines such as Minuit which find a single local minimum. As intuitively expected, this additional level of uncertainty decreases as larger numbers of observables are included.

  5. 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

  6. 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.

  7. 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.

  8. Returning home to die: Circular labour migration and mortality in South Africa1

    Science.gov (United States)

    CLARK, SAMUEL J.; COLLINSON, MARK A.; KAHN, KATHLEEN; DRULLINGER, KYLE; TOLLMAN, STEPHEN M.

    2010-01-01

    Aim: To examine the hypothesis that circular labour migrants who become seriously ill while living away from home return to their rural homes to convalesce and possibly to die. Methods: Drawing on longitudinal data collected by the Agincourt health and demographic surveillance system in rural northeastern South Africa between 1995 and 2004, discrete time event history analysis is used to estimate the likelihood of dying for residents, short-term returning migrants, and long-term returning migrants controlling for sex, age, and historical period. Results: The annual odds of dying for short-term returning migrants are generally 1.1 to 1.9 times (depending on period, sex, and age) higher than those of residents and long-term returning migrants, and these differences are generally highly statistically significant. Further supporting the hypothesis is the fact that the proportion of HIV/TB deaths among short-term returning migrants increases dramatically as time progresses, and short-term returning migrants account for an increasing proportion of all HIV/TB deaths. Conclusions: This evidence strongly suggests that increasing numbers of circular labour migrants of prime working age are becoming ill in the urban areas where they work and coming home to be cared for and eventually to die in the rural areas where their families live. This shifts the burden of caring for them in their terminal illness to their families and the rural healthcare system with significant consequences for the distribution and allocation of health care resources. PMID:17676501

  9. 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

  10. 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

  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. Abnormal Stock Market Returns to Announcements of M&A Banking Deals in Greece 1996-2013

    OpenAIRE

    Anastasios KARAMANOS; George BAKATSELOS; Roena AGOLLI

    2015-01-01

    This study has undertaken a comprehensive empirical analysis of the wealth effects of bank M&As in Greece over the period 1996-2013. The purpose is to measure the performance of merger participants over the acquisition period as a deviation of how shareholders’ actual returns differ from expected returns conditional on the particular process of M&A. The authors develop a conceptual framework that integrates theoretical perspectives from economics, finance, organization theory, strateg...

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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

  18. Barefoot and in a German kitchen: federal parental leave and benefit policy and the return to work after childbirth in Germany.

    Science.gov (United States)

    Ondrich, J; Spiess, C K; Yang, Q

    1996-01-01

    "Since 1979 German federal maternity leave and benefit policy has given women incentives to stay at home and take care of their newborn and youngest children. In 1986 this leave and benefit policy was changed in several ways, turning it into a powerful instrument for delaying mothers' return to work after childbirth.... We estimate post childbirth return to work hazards for women during the federally protected leave protection period and immediately upon completion of this leave period. During the leave mothers are less likely to return to work the longer is the time left in the leave protection period; however, this result cannot be attributed generally to high levels of maternity benefits. When the leave protection period ends, mothers with strong labor force attachment who are still on leave return to their jobs." excerpt

  19. 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

  20. Economic analysis of venture capital funds rate of return on venture activity

    Directory of Open Access Journals (Sweden)

    Usatenko O.V.

    2017-08-01

    Full Text Available The research deals with the topic of the analysis of venture capital funds’ rate of return on venture activity. The discovered venture capital funds have such a peculiarity as the involved investors of various types and concentrated financial resources, which lead to advantages in investing. Based on the analyzed scientific approaches to the evaluation of income rate met by various economic entities the paper determines the optimal indicators of such an analysis developed due to the article research. They are supposed to improve significantly the process of making decisions on venture capital investments. The author suggests to evaluate venture capital funds rate of return on venture activity by means of the basic four indicators usually employed for investment efficiency definition: net profit, internal rate of return, return period and return index. The research presents the examination of rates of return on venture activity of venture capital funds being controlled by a single asset management company. Thus, one can estimate not only the rate of return on venture activity, but also the efficiency of control taken by an asset management company.

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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...

  7. Dynamic structure of stock communities: a comparative study between stock returns and turnover rates

    Science.gov (United States)

    Su, Li-Ling; Jiang, Xiong-Fei; Li, Sai-Ping; Zhong, Li-Xin; Ren, Fei

    2017-07-01

    The detection of community structure in stock market is of theoretical and practical significance for the study of financial dynamics and portfolio risk estimation. We here study the community structures in Chinese stock markets from the aspects of both price returns and turnover rates, by using a combination of the PMFG and infomap methods based on a distance matrix. An empirical study using the overall data set shows that for both returns and turnover rates the largest communities are composed of specific industrial or conceptional sectors and the correlation inside a sector is generally larger than the correlation between different sectors. However, the community structure for turnover rates is more complex than that for returns, which indicates that the interactions between stocks revealed by turnover rates may contain more information. This conclusion is further confirmed by the analysis of the changes in the dynamics of community structures over five sub-periods. Sectors like banks, real estate, health care and New Shanghai take turns to comprise a few of the largest communities in different sub-periods, and more interestingly several specific sectors appear in the communities with different rank orders for returns and turnover rates even in the same sub-period. To better understand their differences, a comparison between the evolution of the returns and turnover rates of the stocks from these sectors is conducted. We find that stock prices only had large changes around important events while turnover rates surged after each of these events relevant to specific sectors, which shows strong evidence that the turnover rates are more susceptible to exogenous shocks than returns and its measurement for community detection may contain more useful information about market structure.

  8. Can trade opportunities and returns be generated in a trend persistent series? Evidence from global indices

    Science.gov (United States)

    Mitra, S. K.; Bawa, Jaslene

    2017-03-01

    In this study, we explore the possibility of generating trade opportunities and returns when a financial stock index series is trend persistent. Through application of Hurst coefficient based on the modified range to standard deviation analysis (Weron, 2002) in a sample of 31 leading global indices during the period December 2000 to November 2015, we found periods of trend persistence. We developed and tested a set of trading strategies on these periods of trend persistent in the financial series and found that significant positive returns can be generated when a series displayed upward trend persistence.

  9. 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)

  10. 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.

  11. Local conditions and uncertainty bands for Semiscale Test S-02-9

    International Nuclear Information System (INIS)

    Varacalle, D.J. Jr.

    1979-01-01

    Analysis was performed to derive local conditions heat transfer parameters and their uncertainties using computer codes and experimentally derived boundary conditions for the Semiscale core for LOCA Test S-02-9. Calculations performed consisted of nominal code cases using best-estimate input parameters and cases where the specified input parameters were perturbed in accordance with the response surface method of uncertainty analysis. The output parameters of interest were those that are used in film boiling heat transfer correlations including enthalpy, pressure, quality, and coolant flow rate. Large uncertainty deviations occurred during low core mass flow periods where the relative flow uncertainties were large. Utilizing the derived local conditions and their associated uncertainties, a study was then made which showed the uncertainty in film boiling heat transfer coefficient varied between 5 and 250%

  12. Factoring uncertainty into restoration modeling of in-situ leach uranium mines

    Science.gov (United States)

    Johnson, Raymond H.; Friedel, Michael J.

    2009-01-01

    Postmining restoration is one of the greatest concerns for uranium in-situ leach (ISL) mining operations. The ISL-affected aquifer needs to be returned to conditions specified in the mining permit (either premining or other specified conditions). When uranium ISL operations are completed, postmining restoration is usually achieved by injecting reducing agents into the mined zone. The objective of this process is to restore the aquifer to premining conditions by reducing the solubility of uranium and other metals in the ground water. Reactive transport modeling is a potentially useful method for simulating the effectiveness of proposed restoration techniques. While reactive transport models can be useful, they are a simplification of reality that introduces uncertainty through the model conceptualization, parameterization, and calibration processes. For this reason, quantifying the uncertainty in simulated temporal and spatial hydrogeochemistry is important for postremedial risk evaluation of metal concentrations and mobility. Quantifying the range of uncertainty in key predictions (such as uranium concentrations at a specific location) can be achieved using forward Monte Carlo or other inverse modeling techniques (trial-and-error parameter sensitivity, calibration constrained Monte Carlo). These techniques provide simulated values of metal concentrations at specified locations that can be presented as nonlinear uncertainty limits or probability density functions. Decisionmakers can use these results to better evaluate environmental risk as future metal concentrations with a limited range of possibilities, based on a scientific evaluation of uncertainty.

  13. 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

  14. 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.

  15. 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

  16. PERCEPTION OF UNCERTAINTY AND OPERATIONAL PERFORMANCE OF THE BRAZILIAN INDUSTRY FROM 2007 TO 2009

    Directory of Open Access Journals (Sweden)

    Marta Sambiase Lombardi

    2010-11-01

    Full Text Available This article poses to explore the relationship between the manager´s perception of uncertainty and the Brazilian industry´s operational performance during the period from 2007 to 2009. This timeframe was chosen because it comprised both positive and negative cycles of the global economic panorama, and thus capable of interfering in the manager´s perception of uncertainty and consequent business strategies. Periods of market fluctuations and more dynamic and complex business environments clearly demonstrate that managerial models which are applicable to static or predictable scenarios, become fragile and of dubious applicability; that is, practices adopted and described in business administration bibliographies might not produce expected results.  A key factor for sound performance is the positioning of companies in relation to future planning (Knight, 2002, the latter defined as actions taken by the entrepreneur given a certain degree of uncertainty, inherent to the management activity.  The relationship between uncertainty and corporate performance has been studied, at least, ever since Knight in 1921. The author affirmed that we live in a world of change and in a world of uncertainty. The level of entrepreneur trust from the National Industry Confederation represented the perception of uncertainty, whilst operational performance was formed as of industrial production and employment IBGE indexes. Results demonstrate that both constructs have equivalent movements during the course of the period, presenting a positive correlation. Key-words: Uncertainty. Operational performance. Trust. 

  17. Equity Returns and Volatilities Before and After the 2007-08 Financial Crisis

    Directory of Open Access Journals (Sweden)

    Dedi Lidija

    2017-05-01

    Full Text Available This paper investigates the linkages among equity markets of four European countries (Germany, France, Italy, UK and the USA in terms of market returns and transmission of volatilities. We use daily exchange traded funds (ETF data from January 2002 to March 2016 and utilize both a Multivariate Autoregressive Moving Average model (MARMA and a Generalized Autoregressive Conditional Heteroskedasticity model (GARCH. We divided the data into three separate periods: before the 2007-08 financial crisis, during the crisis and after the crisis. The results show the existence of significant co-movement of returns in all three selected periods although some important differences before and after the financial crisis are noted. Findings also include marked increases in integration of the markets and thus diminishing diversification opportunities for investors. Volatilities appear to react strongly to market movements and their shocks fade away slowly in all five countries during the crisis period. There is also strong evidence of volatility spillovers particularly during and after the crisis periods.

  18. 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…

  19. Using statistical model to simulate the impact of climate change on maize yield with climate and crop uncertainties

    Science.gov (United States)

    Zhang, Yi; Zhao, Yanxia; Wang, Chunyi; Chen, Sining

    2017-11-01

    Assessment of the impact of climate change on crop productions with considering uncertainties is essential for properly identifying and decision-making agricultural practices that are sustainable. In this study, we employed 24 climate projections consisting of the combinations of eight GCMs and three emission scenarios representing the climate projections uncertainty, and two crop statistical models with 100 sets of parameters in each model representing parameter uncertainty within the crop models. The goal of this study was to evaluate the impact of climate change on maize ( Zea mays L.) yield at three locations (Benxi, Changling, and Hailun) across Northeast China (NEC) in periods 2010-2039 and 2040-2069, taking 1976-2005 as the baseline period. The multi-models ensembles method is an effective way to deal with the uncertainties. The results of ensemble simulations showed that maize yield reductions were less than 5 % in both future periods relative to the baseline. To further understand the contributions of individual sources of uncertainty, such as climate projections and crop model parameters, in ensemble yield simulations, variance decomposition was performed. The results indicated that the uncertainty from climate projections was much larger than that contributed by crop model parameters. Increased ensemble yield variance revealed the increasing uncertainty in the yield simulation in the future periods.

  20. 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.

  1. Return Migrants’ Experience of Access to Care in Corrupt Healthcare Systems

    DEFF Research Database (Denmark)

    Handlos, Line Neerup; Olwig, Karen Fog; Bygbjerg, Ib Christian

    2016-01-01

    unstudied, even though return migrants may be particularly vulnerable to problems related to corruption due to their period of absence from their country of origin. This article investigates how corruption in the healthcare sector affects access to healthcare for refugees who repatriated to Bosnia......Equal and universal access to healthcare services is a core priority for a just health system. A key societal determinant seen to create inequality in access to healthcare is corruption in the healthcare system. How return migrants’ access to healthcare is affected by corruption is largely......, a country with a high level of corruption, from Denmark, a country with a low level of corruption. The study is based on 18 semi-structured interviews with 33 refugees who returned after long-term residence in Denmark. We found that the returned refugees faced greater problems with corruption than...

  2. 26 CFR 301.6103(h)(2)-1 - Disclosure of returns and return information (including taxpayer return information) to and by...

    Science.gov (United States)

    2010-04-01

    ... administration. 301.6103(h)(2)-1 Section 301.6103(h)(2)-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT... Returns Returns and Records § 301.6103(h)(2)-1 Disclosure of returns and return information (including..., shall, to the extent provided by section 6103(h)(2) (A), (B), and (C) and subject to the requirements of...

  3. A new daily dividend-adjusted index for the Danish stock market, 1985-2002: Construction, statistical properties, and return predictability

    DEFF Research Database (Denmark)

    Belter, Klaus; Engsted, Tom; Tanggaard, Carsten

    2005-01-01

    is given. In the second part of the paper we analyze the time-series properties of daily, weekly, and monthly returns, and we present evidence on predictability of multi-period returns. We also compare stock returns with the returns on long-term bonds and short-term money market instruments (that is......We present a new dividend-adjusted blue chip index for the Danish stock market covering the period 1985-2002. In contrast to other indices on the Danish stock market, the index is calculated on a daily basis. In the first part of the paper a detailed description of the construction of the index...

  4. PENGARUH PENGUMUMAN DIVIDEN TERHADAP PERUBAHAN HARGA SAHAM (RETURN SEBELUM DAN SESUDAH EX -DIVIDEND DATE DI

    Directory of Open Access Journals (Sweden)

    R. Andi Sularso

    2003-01-01

    Full Text Available This research objective is to analyze the influence of ex-dividend date announcement in the Jakarta Stock Exchange by taking 14 samples of shares. There are two kinds of samples, increasing dividend and decreasing divindend. 120-days of observation will be divided into 90-days estimation period and 30-days event period, including 15 days before and after the event. The method used in this research is event study that observe the stock price movement in the capital market. To examine the existence of price reaction, the abnormal return test will be conducted during the event period with analysis based on the concpet of CAPM (Capital Assets Pricing Model and the abnormal return test to the increasing and decreasing dividend at the ex-dividend date. The result indicate that at the significant level of 10%, there are two working days which yield the abnormal return that is significant at the increasing dividend. Those are the fourth day before the event date with the value of 0.0011102 or around 0.1%, and the fifth day after the event date with the value of -0.32184 or approximately 3%. Whereas the decreasing divideng reveals that there are three days that deliver the abnormal return which is significant. Those are thirteentg and the second day before the event date with the value of 0.028263 or approximately 2% and 0.0166274 or approximately 1%, as well as at the fifth day after the event date with the value of 0.029105 or 3%. The final conclusion is that stock price will negatively reacted to the announcement of increasing dividend at the ex-dividend date and positively reacted to the announcement of the decreasing dividend at the ex-dividend date. Abstract in Bahasa Indonesia : Penelitian ini bertujuan untuk menganalisis pengaruh pengumuman ex-dividend date di Bursa Efek Jakarta, dengan mengambil sampel 14 saham. Sampel dibagi menjadi dua, yaitu dividen naik dan dividen turun. Periode penelitian selama 120 hari yang dibagi menjadi dua periode

  5. 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.

  6. Estimating uncertainty and its temporal variation related to global climate models in quantifying climate change impacts on hydrology

    Science.gov (United States)

    Shen, Mingxi; Chen, Jie; Zhuan, Meijia; Chen, Hua; Xu, Chong-Yu; Xiong, Lihua

    2018-01-01

    Uncertainty estimation of climate change impacts on hydrology has received much attention in the research community. The choice of a global climate model (GCM) is usually considered as the largest contributor to the uncertainty of climate change impacts. The temporal variation of GCM uncertainty needs to be investigated for making long-term decisions to deal with climate change. Accordingly, this study investigated the temporal variation (mainly long-term) of uncertainty related to the choice of a GCM in predicting climate change impacts on hydrology by using multi-GCMs over multiple continuous future periods. Specifically, twenty CMIP5 GCMs under RCP4.5 and RCP8.5 emission scenarios were adapted to adequately represent this uncertainty envelope, fifty-one 30-year future periods moving from 2021 to 2100 with 1-year interval were produced to express the temporal variation. Future climatic and hydrological regimes over all future periods were compared to those in the reference period (1971-2000) using a set of metrics, including mean and extremes. The periodicity of climatic and hydrological changes and their uncertainty were analyzed using wavelet analysis, while the trend was analyzed using Mann-Kendall trend test and regression analysis. The results showed that both future climate change (precipitation and temperature) and hydrological response predicted by the twenty GCMs were highly uncertain, and the uncertainty increased significantly over time. For example, the change of mean annual precipitation increased from 1.4% in 2021-2050 to 6.5% in 2071-2100 for RCP4.5 in terms of the median value of multi-models, but the projected uncertainty reached 21.7% in 2021-2050 and 25.1% in 2071-2100 for RCP4.5. The uncertainty under a high emission scenario (RCP8.5) was much larger than that under a relatively low emission scenario (RCP4.5). Almost all climatic and hydrological regimes and their uncertainty did not show significant periodicity at the P = .05 significance

  7. Bank Stock Returns in Responding the Contribution of Fundamental and Macroeconomic Effects

    Directory of Open Access Journals (Sweden)

    Ridwan Nurazi

    2016-06-01

    Full Text Available This study attempts to examine the effect of financial fundamentals information using CAMELS ratios and macroeconomics variables surrogated by interest rate, exchange rate, and inflation rate toward stock return. By employing panel data analysis (Pooled Least Squared Model, the results reveal that several financial ratios perform a bit contrary to the theory, in which the ratio of CAR shows positive sign but insignificantly contributes to stock returns. Also, the ratio of NPL does not affect the return. In fact, ROE and LDR positively and significantly contribute toward banks’ stock return. Meanwhile, NIM and BOPO show negative signs. The other macroeconomic variables, interest rate (IR, exchange rate (ER and inflation rate (INF are consistent with the a priori expectation, in which those variables negatively and significantly contribute to stock return of 16 banks, for the observation period from 2002 to 2011 in the Indonesian banking sector.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. Analysis on Calibration and Uncertainty for TD-LTE Radio Test System

    Directory of Open Access Journals (Sweden)

    Zhang Weipeng

    2014-06-01

    Full Text Available TD-LTE base station radio test system measures radio signal with a required accuracy, so calibration need to be done for transmission path between base station and measurement instruments before test. Considering Transmitter OFF Power measurement within OFF period, modulated signal generator and spectrum analyzer inside test system is used for calibration, to get accurate transmission parameters of the paths, and to reduce test cost without more instruments. The paper describes the uncertainty of test system, analyzes uncertainty contribution of interface mismatch, calculates uncertainty for Transmitter OFF Power measurement, uncertainty is 1.193 dB, within the requirement of 3GPP specification.

  13. 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.

  14. Analyzing traffic source impact on returning visitors ratio in information provider website

    Science.gov (United States)

    Prasetio, A.; Sari, P. K.; Sharif, O. O.; Sofyan, E.

    2016-04-01

    Web site performance, especially returning visitor is an important metric for an information provider web site. Since high returning visitor is a good indication of a web site’s visitor loyalty, it is important to find a way to improve this metric. This research investigated if there is any difference on returning visitor metric among three web traffic sources namely direct, referral and search. Monthly returning visitor and total visitor from each source is retrieved from Google Analytics tools and then calculated to measure returning visitor ratio. The period of data observation is from July 2012 to June 2015 resulting in a total of 108 samples. These data then analysed using One-Way Analysis of Variance (ANOVA) to address our research question. The results showed that different traffic source has significantly different returning visitor ratio especially between referral traffic source and the other two traffic sources. On the other hand, this research did not find any significant difference between returning visitor ratio from direct and search traffic sources. The owner of the web site can focus to multiply referral links from other relevant sites.

  15. 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

  16. 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.

  17. 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.

  18. 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...

  19. Return Stroke Current Reflections in Rocket-Triggered Lightning

    Science.gov (United States)

    Caicedo, J.; Uman, M. A.; Jordan, D.; Biagi, C. J.; Hare, B.

    2015-12-01

    In the six years from 2009 to 2014, there have been eight triggered flashes at the ICLRT, from a total of 125, in which a total of ten return stroke channel-base currents exhibited a dip 3.0 to 16.6 μs after the initial current peak. Close range electric field measurements show a related dip following the initial electric field peak, and electric field derivative measurements show an associated bipolar pulse, confirming that this phenomenon is not an instrumentation effect in the current measurement. For six of the eight flashes, high-speed video frames show what appears to be suspended sections of unexploded triggering wire at heights of about 150 to 300 m that are illuminated when the upward current wave reaches them. The suspended wire can act as an impedance discontinuity, perhaps as it explodes, and cause a downward reflection of some portion of the upward-propagating current wave. This reflected wave travels down the channel and causes the dip in the measured channel-base current when it reaches ground and reflects upward. The modified transmission line model with exponential decay (MTLE) is used to model the close electric field and electric field derivatives of the postulated initial and reflected current waves, starting with the measured channel base current, and the results are compared favorably with measurements made at distances ranging from 92 to 444 m. From the measured time between current impulse initiation and the time the current reflection reaches the channel base and the current dip initiates, along with the reflection height from the video records, we find the average return stroke current speed for each of the ten strokes to be from 0.28 to 1.9×108 ms-1, with an error of ±0.01×108 ms-1 due to a ±0.1 μs uncertainty in the measurement. This represents the first direct measurement of return stroke current speed, all previous return stroke speed measurements being derived from the luminosity of the process.

  20. 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%,

  1. 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%,

  2. 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%,

  3. Assessing the Feasibility of Managed Aquifer Recharge for Irrigation under Uncertainty

    Directory of Open Access Journals (Sweden)

    Muhammad Arshad

    2014-09-01

    Full Text Available Additional storage of water is a potential option to meet future water supply goals. Financial comparisons are needed to improve decision making about whether to store water in surface reservoirs or below ground, using managed aquifer recharge (MAR. In some places, the results of cost-benefit analysis show that MAR is financially superior to surface storage. However, uncertainty often exists as to whether MAR systems will remain operationally effective and profitable in the future, because the profitability of MAR is dependent on many uncertain technical and financial variables. This paper introduces a method to assess the financial feasibility of MAR under uncertainty. We assess such uncertainties by identification of cross-over points in break-even analysis. Cross-over points are the thresholds where MAR and surface storage have equal financial returns. Such thresholds can be interpreted as a set of minimum requirements beyond which an investment in MAR may no longer be worthwhile. Checking that these thresholds are satisfied can improve confidence in decision making. Our suggested approach can also be used to identify areas that may not be suitable for MAR, thereby avoiding expensive hydrogeological and geophysical investigations.

  4. Effect of precipitation spatial distribution uncertainty on the uncertainty bounds of a snowmelt runoff model output

    Science.gov (United States)

    Jacquin, A. P.

    2012-04-01

    This study analyses the effect of precipitation spatial distribution uncertainty on the uncertainty bounds of a snowmelt runoff model's discharge estimates. Prediction uncertainty bounds are derived using the Generalized Likelihood Uncertainty Estimation (GLUE) methodology. The model analysed is a conceptual watershed model operating at a monthly time step. The model divides the catchment into five elevation zones, where the fifth zone corresponds to the catchment glaciers. Precipitation amounts at each elevation zone i are estimated as the product between observed precipitation (at a single station within the catchment) and a precipitation factor FPi. Thus, these factors provide a simplified representation of the spatial variation of precipitation, specifically the shape of the functional relationship between precipitation and height. In the absence of information about appropriate values of the precipitation factors FPi, these are estimated through standard calibration procedures. The catchment case study is Aconcagua River at Chacabuquito, located in the Andean region of Central Chile. Monte Carlo samples of the model output are obtained by randomly varying the model parameters within their feasible ranges. In the first experiment, the precipitation factors FPi are considered unknown and thus included in the sampling process. The total number of unknown parameters in this case is 16. In the second experiment, precipitation factors FPi are estimated a priori, by means of a long term water balance between observed discharge at the catchment outlet, evapotranspiration estimates and observed precipitation. In this case, the number of unknown parameters reduces to 11. The feasible ranges assigned to the precipitation factors in the first experiment are slightly wider than the range of fixed precipitation factors used in the second experiment. The mean squared error of the Box-Cox transformed discharge during the calibration period is used for the evaluation of the

  5. 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.

  6. 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

  7. 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...

  8. Development and comparison of Bayesian modularization method in uncertainty assessment of hydrological models

    Science.gov (United States)

    Li, L.; Xu, C.-Y.; Engeland, K.

    2012-04-01

    With respect to model calibration, parameter estimation and analysis of uncertainty sources, different approaches have been used in hydrological models. Bayesian method is one of the most widely used methods for uncertainty assessment of hydrological models, which incorporates different sources of information into a single analysis through Bayesian theorem. However, none of these applications can well treat the uncertainty in extreme flows of hydrological models' simulations. This study proposes a Bayesian modularization method approach in uncertainty assessment of conceptual hydrological models by considering the extreme flows. It includes a comprehensive comparison and evaluation of uncertainty assessments by a new Bayesian modularization method approach and traditional Bayesian models using the Metropolis Hasting (MH) algorithm with the daily hydrological model WASMOD. Three likelihood functions are used in combination with traditional Bayesian: the AR (1) plus Normal and time period independent model (Model 1), the AR (1) plus Normal and time period dependent model (Model 2) and the AR (1) plus multi-normal model (Model 3). The results reveal that (1) the simulations derived from Bayesian modularization method are more accurate with the highest Nash-Sutcliffe efficiency value, and (2) the Bayesian modularization method performs best in uncertainty estimates of entire flows and in terms of the application and computational efficiency. The study thus introduces a new approach for reducing the extreme flow's effect on the discharge uncertainty assessment of hydrological models via Bayesian. Keywords: extreme flow, uncertainty assessment, Bayesian modularization, hydrological model, WASMOD

  9. Forecasting volatility in gold returns under the GARCH, IGARCH and FIGARCH frameworks: New evidence

    Science.gov (United States)

    Bentes, Sonia R.

    2015-11-01

    This study employs three volatility models of the GARCH family to examine the volatility behavior of gold returns. Much of the literature on this topic suggests that gold plays a fundamental role as a hedge and safe haven against adverse market conditions, which is particularly relevant in periods of high volatility. This makes understanding gold volatility important for a number of theoretical and empirical applications, namely investment valuation, portfolio selection, risk management, monetary policy-making, futures and option pricing, hedging strategies and value-at-risk (VaR) policies (e.g. Baur and Lucey (2010)). We use daily data from August 2, 1976 to February 6, 2015 and divide the full sample into two periods: the in-sample period (August 2, 1976-October 24, 2008) is used to estimate model coefficients, while the out-of-sample period (October 27, 2008-February 6, 2015) is for forecasting purposes. Specifically, we employ the GARCH(1,1), IGARCH(1,1) and FIGARCH(1, d,1) specifications. The results show that the FIGARCH(1, d,1) is the best model to capture linear dependence in the conditional variance of the gold returns as given by the information criteria. It is also found to be the best model to forecast the volatility of gold returns.

  10. ENERGY SYSTEM DEVELOPMENT AND LOAD MANAGEMENT THROUGH THE REHABILITATION AND RETURN TO PLAY PROCESS.

    Science.gov (United States)

    Morrison, Scot; Ward, Patrick; duManoir, Gregory R

    2017-08-01

    Return-to-play from injury is a complex process involving many factors including the balancing of tissue healing rates with the development of biomotor abilities. This process requires interprofessional cooperation to ensure success. An often-overlooked aspect of return-to-play is the development and maintenance of sports specific conditioning while monitoring training load to ensure that the athlete's training stimulus over the rehabilitation period is appropriate to facilitate a successful return to play. The purpose of this clinical commentary is to address the role of energy systems training as part of the return-to-play process. Additionally the aim is to provide practitioners with an overview of practical sports conditioning training methods and monitoring strategies to allow them to direct and quantify the return-to-play process. 5.

  11. The Transmission of U.S. Election Cycles to International Stock Returns

    OpenAIRE

    Stephen R Foerster; John J Schmitz

    1997-01-01

    This paper examines the international pervasiveness and importance of the previously uncovered four-year U.S. election cycle whereby U.S. stock returns are significantly lower, and negative, in year 2 following U.S. presidential election relative to years 1, 3 and 4. All eighteen countries examined over the 1957 to 1996 time period possess lower local currency stock market capital gains returns in year 2 (-0.66%) relative to the average capital gains of years 1, 3 and 4 (11.68%). These predom...

  12. 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.

  13. 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...

  14. 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.

  15. Earnings quality measures and excess returns: A case study of Tehran Stock Exchange

    Directory of Open Access Journals (Sweden)

    Hassan Hemmati

    2013-04-01

    Full Text Available This paper presents an empirical investigation to study the relationship between earning quality measure and excess returns on selected firms trading on Tehran Stock Exchange. The purpose of this study is to find the relative advantage of income figures reported in formal financial statements. The study uses hedge return, six accounting ratios and three market ratios and performs the study over the period of 2001-2011 using 56 firms whose shares were traded on Tehran Stock Exchange. The proposed study uses regression analysis as well as structural equation modeling. The results of this study indicate that market based figures are more influencing than accounting based ratios on hedge return. In other words, hedge return for persistency index was more predictable than smoothness and abnormal accruals. However, on the contrary to what we expected, hedge return for accruals was not more than other accounting based figures.

  16. Recognizing and responding to uncertainty: a grounded theory of nurses' uncertainty.

    Science.gov (United States)

    Cranley, Lisa A; Doran, Diane M; Tourangeau, Ann E; Kushniruk, Andre; Nagle, Lynn

    2012-08-01

    There has been little research to date exploring nurses' uncertainty in their practice. Understanding nurses' uncertainty is important because it has potential implications for how care is delivered. The purpose of this study is to develop a substantive theory to explain how staff nurses experience and respond to uncertainty in their practice. Between 2006 and 2008, a grounded theory study was conducted that included in-depth semi-structured interviews. Fourteen staff nurses working in adult medical-surgical intensive care units at two teaching hospitals in Ontario, Canada, participated in the study. The theory recognizing and responding to uncertainty characterizes the processes through which nurses' uncertainty manifested and how it was managed. Recognizing uncertainty involved the processes of assessing, reflecting, questioning, and/or being unable to predict aspects of the patient situation. Nurses' responses to uncertainty highlighted the cognitive-affective strategies used to manage uncertainty. Study findings highlight the importance of acknowledging uncertainty and having collegial support to manage uncertainty. The theory adds to our understanding the processes involved in recognizing uncertainty, strategies and outcomes of managing uncertainty, and influencing factors. Tailored nursing education programs should be developed to assist nurses in developing skills in articulating and managing their uncertainty. Further research is needed to extend, test and refine the theory of recognizing and responding to uncertainty to develop strategies for managing uncertainty. This theory advances the nursing perspective of uncertainty in clinical practice. The theory is relevant to nurses who are faced with uncertainty and complex clinical decisions, to managers who support nurses in their clinical decision-making, and to researchers who investigate ways to improve decision-making and care delivery. ©2012 Sigma Theta Tau International.

  17. LABORATORY EVALUATION OF AIR FLOW MEASUREMENT METHODS FOR RESIDENTIAL HVAC RETURNS

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Iain; Stratton, Chris

    2015-02-01

    This project improved the accuracy of air flow measurements used in commissioning California heating and air conditioning systems in Title 24 (Building and Appliance Efficiency Standards), thereby improving system performance and efficiency of California residences. The research team at Lawrence Berkeley National Laboratory addressed the issue that typical tools used by contractors in the field to test air flows may not be accurate enough to measure return flows used in Title 24 applications. The team developed guidance on performance of current diagnostics as well as a draft test method for use in future evaluations. The series of tests performed measured air flow using a range of techniques and devices. The measured air flows were compared to reference air flow measurements using inline air flow meters built into the test apparatus. The experimental results showed that some devices had reasonable results (typical errors of 5 percent or less) but others had much bigger errors (up to 25 percent). Because manufacturers’ accuracy estimates for their equipment do not include many of the sources of error found in actual field measurements (and replicated in the laboratory testing in this study) it is essential for a test method that could be used to determine the actual uncertainty in this specific application. The study team prepared a draft test method through ASTM International to determine the uncertainty of air flow measurements at residential heating ventilation and air conditioning returns and other terminals. This test method, when finalized, can be used by the Energy Commission and other entities to specify required accuracy of measurement devices used to show compliance with standards.

  18. 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

  19. 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.

  20. Applying an animal model to quantify the uncertainties of an image-based 4D-CT algorithm

    International Nuclear Information System (INIS)

    Pierce, Greg; Battista, Jerry; Wang, Kevin; Lee, Ting-Yim

    2012-01-01

    The purpose of this paper is to use an animal model to quantify the spatial displacement uncertainties and test the fundamental assumptions of an image-based 4D-CT algorithm in vivo. Six female Landrace cross pigs were ventilated and imaged using a 64-slice CT scanner (GE Healthcare) operating in axial cine mode. The breathing amplitude pattern of the pigs was varied by periodically crimping the ventilator gas return tube during the image acquisition. The image data were used to determine the displacement uncertainties that result from matching CT images at the same respiratory phase using normalized cross correlation (NCC) as the matching criteria. Additionally, the ability to match the respiratory phase of a 4.0 cm subvolume of the thorax to a reference subvolume using only a single overlapping 2D slice from the two subvolumes was tested by varying the location of the overlapping matching image within the subvolume and examining the effect this had on the displacement relative to the reference volume. The displacement uncertainty resulting from matching two respiratory images using NCC ranged from 0.54 ± 0.10 mm per match to 0.32 ± 0.16 mm per match in the lung of the animal. The uncertainty was found to propagate in quadrature, increasing with number of NCC matches performed. In comparison, the minimum displacement achievable if two respiratory images were matched perfectly in phase ranged from 0.77 ± 0.06 to 0.93 ± 0.06 mm in the lung. The assumption that subvolumes from separate cine scan could be matched by matching a single overlapping 2D image between to subvolumes was validated. An in vivo animal model was developed to test an image-based 4D-CT algorithm. The uncertainties associated with using NCC to match the respiratory phase of two images were quantified and the assumption that a 4.0 cm 3D subvolume can by matched in respiratory phase by matching a single 2D image from the 3D subvolume was validated. The work in this paper shows the image-based 4D

  1. Return to contact sports following infectious mononucleosis: the role of serial ultrasonography.

    Science.gov (United States)

    O'Connor, Tony E; Skinner, Liam J; Kiely, Patrick; Fenton, John E

    2011-08-01

    Splenic rupture is a rare but potentially fatal complication of infectious mononucleosis. Athletes returning to contact sports following infectious mononucleosis are at potential risk of splenic rupture secondary to abdominal trauma. No clear consensus exists as to when it is safe to allow these athletes to return to contact sports. Suggested periods of abstinence have ranged from 2 weeks to 6 months. We outline our experiences with the use of abdominal ultrasonography at 1 month after the diagnosis of infectious mononucleosis as a means of determining when athletes can safely return to contact sports. Our study group was made up of 19 such patients (mean age: 16.7 yr). We found that 16 of these patients (84%) had normal splenic dimensions on ultrasonography 1 month after diagnosis, and they were therefore allowed to return to contact sports. While the remaining 3 patients had an enlarged spleen at 1 month, their splenic dimensions had all returned to normal when ultrasonographic examination was repeated at 2 months postdiagnosis. We conclude that serial abdominal ultrasonography allows for informed decision making in determining when athletes can safely return to contact sports following infectious mononucleosis.

  2. End-of-the-year economic growth and time-varying expected returns

    DEFF Research Database (Denmark)

    Møller, Stig V.; Rangvid, Jesper

    2015-01-01

    We show that macroeconomic growth at the end of the year (fourth quarter or December) strongly influences expected returns on risky financial assets, whereas economic growth during the rest of the year does not. We find this pattern for many different asset classes, across different time periods......, and for US and international data. We also show that movements in the surplus consumption ratio of Campbell and Cochrane (1999) , a theoretically well-founded measure of time-varying risk aversion linked to macroeconomic growth, influence expected returns stronger during the fourth quarter than the other...

  3. RELATIONSHIP BETWEEN STOCK MARKET RETURNS AND EXCHANGERATES IN EMERGING STOCK MARKETS

    Directory of Open Access Journals (Sweden)

    M.N. Arshad

    2017-04-01

    Full Text Available Abstract-This paper aims to study the relationship between stock market returns and exchange rates in emerging stock markets including Malaysia, Singapore, Thailand, Indonesia and Philippines. The data is taken from January 2003 to December 2012 using weekly closing indices and separated in two periods; before (2003-2007 and second, after (2008-2012 the financial crisis of 2008. Johansen-Juselius (JJ. Granger causality tests show that unidirectional causality exists between the stock market returns and exchange rates for Thailand before the financial crisis, whilst, for Indonesia and Singapore, the unidirectional causality between the two variables is detected in the period after the financial crisis. Error Correction Model (ECM indicates the existence of long run causality between the two variables for Philippines. This study also finds that most of the emerging stock markets are informationally inefficient.

  4. Influence of short-term sampling parameters on the uncertainty of the Lden environmental noise indicator

    International Nuclear Information System (INIS)

    Mateus, M; Carrilho, J Dias; Da Silva, M Gameiro

    2015-01-01

    The present study deals with the influence of the sampling parameters on the uncertainty of noise equivalent level in environmental noise measurements. The study has been carried out through the test of different sampling strategies doing resampling trials over continuous monitoring noise files obtained previously in an urban location in the city of Coimbra, in Portugal. On short term measurements, not only the duration of the sampling episodes but also its number have influence on the uncertainty of the result. This influence is higher for the time periods where sound levels suffer a greater variation, such as during the night period. In this period, in case both parameters (duration and number of sampling episodes) are not carefully selected, the uncertainty level can reach too high values contributing to a loss of precision of the measurements. With the obtained data it was investigated the sampling parameters influence on the long term noise indicator uncertainty, calculated according the Draft 1st CD ISO 1996-2:2012 proposed method. It has been verified that this method allows the possibility of defining a general methodology which enables the setting of the parameters once the precision level is fixed. For the three reference periods defined for environmental noise (day, evening and night), it was possible to derive a two variable power law representing the uncertainty of the determined values as a function of the two sampling parameters: duration of sampling episode and number of episodes

  5. Return to Play After Forearm and Hand Injuries in the National Basketball Association.

    Science.gov (United States)

    Morse, Kyle W; Hearns, Krystle A; Carlson, Michelle Gerwin

    2017-02-01

    Hand injuries can result in significant time away from competition for professional basketball players. Time to return to play after hand injuries in elite athletes has not been well described. To report the return to play from metacarpal fractures, phalangeal fractures, and thumb ligament tears in National Basketball Association (NBA) players over a 5-year period. Descriptive epidemiology study. The NBA transaction report was analyzed from January 2009 to May 2014. Players were identified if they were added to the inactive list (IL), missed games due to their injury, or underwent surgery as a result of hand injury. Number of games missed due to injury, days spent on the IL, and age at injury were calculated by injury type and location. One hundred thirty-seven injuries were identified: 39 injuries to the hand and 98 injuries to the finger. Three major injury patterns were identified and analyzed: metacarpal fractures (n = 26), phalangeal fractures (n = 33), and thumb ligament tears (n = 9). The type of injury sustained affected return to play ( P basketball players can lead to prolonged periods of time away from competition, especially after surgery. This study provides guidelines on expected return to play in the NBA after these common hand injuries.

  6. Modeling the distribution of extreme share return in Malaysia using Generalized Extreme Value (GEV) distribution

    Science.gov (United States)

    Hasan, Husna; Radi, Noor Fadhilah Ahmad; Kassim, Suraiya

    2012-05-01

    Extreme share return in Malaysia is studied. The monthly, quarterly, half yearly and yearly maximum returns are fitted to the Generalized Extreme Value (GEV) distribution. The Augmented Dickey Fuller (ADF) and Phillips Perron (PP) tests are performed to test for stationarity, while Mann-Kendall (MK) test is for the presence of monotonic trend. Maximum Likelihood Estimation (MLE) is used to estimate the parameter while L-moments estimate (LMOM) is used to initialize the MLE optimization routine for the stationary model. Likelihood ratio test is performed to determine the best model. Sherman's goodness of fit test is used to assess the quality of convergence of the GEV distribution by these monthly, quarterly, half yearly and yearly maximum. Returns levels are then estimated for prediction and planning purposes. The results show all maximum returns for all selection periods are stationary. The Mann-Kendall test indicates the existence of trend. Thus, we ought to model for non-stationary model too. Model 2, where the location parameter is increasing with time is the best for all selection intervals. Sherman's goodness of fit test shows that monthly, quarterly, half yearly and yearly maximum converge to the GEV distribution. From the results, it seems reasonable to conclude that yearly maximum is better for the convergence to the GEV distribution especially if longer records are available. Return level estimates, which is the return level (in this study return amount) that is expected to be exceeded, an average, once every t time periods starts to appear in the confidence interval of T = 50 for quarterly, half yearly and yearly maximum.

  7. An analysis of security price risk and return among publicly traded pharmacy corporations.

    Science.gov (United States)

    Gilligan, Adrienne M; Skrepnek, Grant H

    2013-01-01

    Community pharmacies have been subject to intense and increasing competition in the past several decades. To determine the security price risk and rate of return of publicly traded pharmacy corporations present on the major U.S. stock exchanges from 1930 to 2009. The Center of Research in Security Prices (CRSP) database was used to examine monthly security-level stock market prices in this observational retrospective study. The primary outcome of interest was the equity risk premium, with analyses focusing upon financial metrics associated with risk and return based upon modern portfolio theory (MPT) including: abnormal returns (i.e., alpha), volatility (i.e., beta), and percentage of returns explained (i.e., adjusted R(2)). Three equilibrium models were estimated using random-effects generalized least squares (GLS): 1) the Capital Asset Pricing Model (CAPM); 2) Fama-French Three-Factor Model; and 3) Carhart Four-Factor Model. Seventy-five companies were examined from 1930 to 2009, with overall adjusted R(2) values ranging from 0.13 with the CAPM to 0.16 with the Four-Factor model. Alpha was not significant within any of the equilibrium models across the entire 80-year time period, though was found from 1999 to 2009 in the Three- and Four-Factor models to be associated with a large, significant, and negative risk-adjusted abnormal returns of -33.84%. Volatility varied across specific time periods based upon the financial model employed. This investigation of risk and return within publicly listed pharmacy corporations from 1930 to 2009 found that substantial losses were incurred particularly from 1999 to 2009, with risk-adjusted security valuations decreasing by one-third. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. 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

  9. 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

  10. Accounting- versus economic-based rates of return: implications for profitability measures in the pharmaceutical industry.

    Science.gov (United States)

    Skrepnek, Grant H

    2004-01-01

    Accounting-based profits have indicated that pharmaceutical firms have achieved greater returns relative to other sectors. However, partially due to the theoretically inappropriate reporting of research and development (R&D) expenditures according to generally accepted accounting principles, evidence suggests that a substantial and upward bias is present in accounting-based rates of return for corporations with high levels of intangible assets. Given the intensity of R&D in pharmaceutical firms, accounting-based profit metrics in the drug sector may be affected to a greater extent than other industries. The aim of this work was to address measurement issues associated with corporate performance and factors that contribute to the bias within accounting-based rates of return. Seminal and broadly cited works on the subject of accounting- versus economic-based rates of return were reviewed from the economic and finance literature, with an emphasis placed on issues and scientific evidence directly related to the drug development process and pharmaceutical industry. With international convergence and harmonization of accounting standards being imminent, stricter adherence to theoretically sound economic principles is advocated, particularly those based on discounted cash-flow methods. Researchers, financial analysts, and policy makers must be cognizant of the biases and limitations present within numerous corporate performance measures. Furthermore, the development of more robust and valid economic models of the pharmaceutical industry is required to capture the unique dimensions of risk and return of the drug development process. Empiric work has illustrated that estimates of economic-based rates of return range from approximately 2 to approximately 11 percentage points below various accounting-based rates of return for drug companies. Because differences in the nature of risk and uncertainty borne by drug manufacturers versus other sectors make comparative assessments

  11. A Comparative Study of CAPM and Seven Factors Risk Adjusted Return Model

    Directory of Open Access Journals (Sweden)

    Madiha Riaz Bhatti

    2014-12-01

    Full Text Available This study is a comparison and contrast of the predictive powers of two asset pricing models: CAPM and seven factor risk-return adjusted model, to explain the cross section of stock rate of returns in the financial sector listed at Karachi Stock Exchange (KSE. To test the models daily returns from January 2013 to February 2014 have been taken and the excess returns of portfolios are regressed on explanatory variables. The results of the tested models indicate that the models are valid and applicable in the financial market of Pakistan during the period under study, as the intercepts are not significantly different from zero. It is consequently established from the findings that all the explanatory variables explain the stock returns in the financial sector of KSE. In addition, the results of this study show that addition of more explanatory variables to the single factor CAPM results in reasonably high values of R2. These results provide substantial support to fund managers, investors and financial analysts in making investment decisions.

  12. DAMPAK PEMODERASIAN KOMPONEN ARUS KAS TERHADAP HUBUNGAN LABA AKUNTANSI DENGAN RETURN SAHAM

    Directory of Open Access Journals (Sweden)

    Hendy Hermawan

    2012-02-01

    Full Text Available Accurate information regarding listed companies is crucial to minimize investment risk. This research aims to examine the effect of accounting income on stock return, and the effect of cash flow from operation, cash flow from investment, and cash flow from financing activities respectively as moderating variables on the relationship between accounting income and stock return of manufacturer listed on the Jakarta Stock Exchange. There were 161 manufacturing companies listed during 2001 to 2005, and 39 of them are selected as sample research using purposive sampling method. With 5 year research period, there are 195 observations done. Data then are analyzed using multiple linear regressions. Results show that accounting income affect stock return significantly, which is shown by greater value of t count compare to t table. While cash flow from operation, investment, and financing activities are not able to moderate relationship between accounting income and stock return

  13. Measuring viability of pacs during reform period in Maharashtra: A case study

    OpenAIRE

    Shah, Deepak

    2007-01-01

    The study showed a reduction in the operational efficiency of the selected PACS during the post-economic reform period as against the pre-economic reform period. The operational efficiency was measured in respect of various liquidity ratio, profitability ratios and financial leverage ratios. Not only the selected societies showed a decline in their current ratio, rate of return on assets, return on owner’s equity and Marginal Efficiency of Capital (MEC) but also showed higher dependency on le...

  14. Low cost metamodel for robust design of periodic nonlinear coupled micro-systems

    Directory of Open Access Journals (Sweden)

    Chikhaoui K.

    2016-01-01

    Full Text Available To achieve robust design, in presence of uncertainty, nonlinearity and structural periodicity, a metamodel combining the Latin Hypercube Sampling (LHS method for uncertainty propagation and an enriched Craig-Bampton Component Mode Synthesis approach (CB-CMS for model reduction is proposed. Its application to predict the time responses of a stochastic periodic nonlinear micro-system proves its efficiency in terms of accuracy and reduction of computational cost.

  15. 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.

  16. 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)

  17. 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)

  18. 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

  19. 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

  20. Evidence of Large Fluctuations of Stock Return and Financial Crises from Turkey: Using Wavelet Coherency and Varma Modeling to Forecast Stock Return

    Science.gov (United States)

    Oygur, Tunc; Unal, Gazanfer

    Shocks, jumps, booms and busts are typical large fluctuation markers which appear in crisis. Models and leading indicators vary according to crisis type in spite of the fact that there are a lot of different models and leading indicators in literature to determine structure of crisis. In this paper, we investigate structure of dynamic correlation of stock return, interest rate, exchange rate and trade balance differences in crisis periods in Turkey over the period between October 1990 and March 2015 by applying wavelet coherency methodologies to determine nature of crises. The time period includes the Turkeys currency and banking crises; US sub-prime mortgage crisis and the European sovereign debt crisis occurred in 1994, 2001, 2008 and 2009, respectively. Empirical results showed that stock return, interest rate, exchange rate and trade balance differences are significantly linked during the financial crises in Turkey. The cross wavelet power, the wavelet coherency, the multiple wavelet coherency and the quadruple wavelet coherency methodologies have been used to examine structure of dynamic correlation. Moreover, in consequence of quadruple and multiple wavelet coherence, strongly correlated large scales indicate linear behavior and, hence VARMA (vector autoregressive moving average) gives better fitting and forecasting performance. In addition, increasing the dimensions of the model for strongly correlated scales leads to more accurate results compared to scalar counterparts.

  1. Factors Affecting the Return Stock Company in Indonesia Stock Exchange (IDX LQ45 in Years 2012-2015

    Directory of Open Access Journals (Sweden)

    Fangki A. Sorongan

    2016-03-01

    Full Text Available This research aimed to determine the effect of partially and jointly independent variable of Debt to Equity Ratio (DER, Return on Equity (ROA, Return on Equity (ROE, and Net Profit Margin (NPM against the dependent variable on the stock return. Objects of this research were companies listed on the Indonesia Stock Exchange (BEI LQ45 continuously for four years in the period 2012-2015. Companies that qualify for this research were 28 companies. Based on this research, the conclusions indicate that all four independent variables; Debt to Equity Ratio (DER, Return on Equity (ROA, Return on Equity (ROE, and Net Profit Margin (NPM, either jointly or partially give the significant effect on return stock.

  2. 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...

  3. Managing risk and expected financial return from selective expansion of operating room capacity: mean-variance analysis of a hospital's portfolio of surgeons.

    Science.gov (United States)

    Dexter, Franklin; Ledolter, Johannes

    2003-07-01

    Surgeons using the same amount of operating room (OR) time differ in their achieved hospital contribution margins (revenue minus variable costs) by >1000%. Thus, to improve the financial return from perioperative facilities, OR strategic decisions should selectively focus additional OR capacity and capital purchasing on a few surgeons or subspecialties. These decisions use estimates of each surgeon's and/or subspecialty's contribution margin per OR hour. The estimates are subject to uncertainty (e.g., from outliers). We account for the uncertainties by using mean-variance portfolio analysis (i.e., quadratic programming). This method characterizes the problem of selectively expanding OR capacity based on the expected financial return and risk of different portfolios of surgeons. The assessment reveals whether the choices, of which surgeons have their OR capacity expanded, are sensitive to the uncertainties in the surgeons' contribution margins per OR hour. Thus, mean-variance analysis reduces the chance of making strategic decisions based on spurious information. We also assess the financial benefit of using mean-variance portfolio analysis when the planned expansion of OR capacity is well diversified over at least several surgeons or subspecialties. Our results show that, in such circumstances, there may be little benefit from further changing the portfolio to reduce its financial risk. Surgeon and subspecialty specific hospital financial data are uncertain, a fact that should be taken into account when making decisions about expanding operating room capacity. We show that mean-variance portfolio analysis can incorporate this uncertainty, thereby guiding operating room management decision-making and reducing the chance of a strategic decision being made based on spurious information.

  4. The Information Content of Corridor Volatility Measures During Calm and Turmoil Periods

    Directory of Open Access Journals (Sweden)

    Elyas Elyasiani

    2017-12-01

    Full Text Available Measurement of volatility is of paramount importance in finance because of the effects on risk measurement and risk management. Corridor implied volatility measures allow us to disentangle the volatility of positive returns from that of negative returns, providing investors with additional information beyond standard market volatility. The aim of the paper is twofold. First, to propose different types of corridor implied volatility and some combinations of them as risk indicators, in order to provide useful information about investors’ sentiment and future market returns. Second, to investigate their usefulness in prediction of market returns under different market conditions (with a particular focus on the subprime crisis and the European debt crisis. The data set consists of daily index options traded on the Italian market and covers the 2005–2014 period. We find that upside corridor implied volatility measure embeds the highest information content about contemporaneous market returns, claiming the superiority of call options in measuring current sentiment in the market. Moreover, both upside and downside volatilities can be considered as barometers of investors’ fear. The volatility measures proposed have forecasting power on future returns only during high volatility periods and in particular during the European debt crisis. The explanatory power on future market returns improves when two of the proposed volatility measures are combined together in the same model.

  5. 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.

  6. Prediction uncertainty and data worth assessment for groundwater transport times in an agricultural catchment

    Science.gov (United States)

    Zell, Wesley O.; Culver, Teresa B.; Sanford, Ward E.

    2018-06-01

    Uncertainties about the age of base-flow discharge can have serious implications for the management of degraded environmental systems where subsurface pathways, and the ongoing release of pollutants that accumulated in the subsurface during past decades, dominate the water quality signal. Numerical groundwater models may be used to estimate groundwater return times and base-flow ages and thus predict the time required for stakeholders to see the results of improved agricultural management practices. However, the uncertainty inherent in the relationship between (i) the observations of atmospherically-derived tracers that are required to calibrate such models and (ii) the predictions of system age that the observations inform have not been investigated. For example, few if any studies have assessed the uncertainty of numerically-simulated system ages or evaluated the uncertainty reductions that may result from the expense of collecting additional subsurface tracer data. In this study we combine numerical flow and transport modeling of atmospherically-derived tracers with prediction uncertainty methods to accomplish four objectives. First, we show the relative importance of head, discharge, and tracer information for characterizing response times in a uniquely data rich catchment that includes 266 age-tracer measurements (SF6, CFCs, and 3H) in addition to long term monitoring of water levels and stream discharge. Second, we calculate uncertainty intervals for model-simulated base-flow ages using both linear and non-linear methods, and find that the prediction sensitivity vector used by linear first-order second-moment methods results in much larger uncertainties than non-linear Monte Carlo methods operating on the same parameter uncertainty. Third, by combining prediction uncertainty analysis with multiple models of the system, we show that data-worth calculations and monitoring network design are sensitive to variations in the amount of water leaving the system via

  7. Ground surface temperature and continental heat gain: uncertainties from underground

    International Nuclear Information System (INIS)

    Beltrami, Hugo; Matharoo, Gurpreet S; Smerdon, Jason E

    2015-01-01

    Temperature changes at the Earth's surface propagate and are recorded underground as perturbations to the equilibrium thermal regime associated with the heat flow from the Earth's interior. Borehole climatology is concerned with the analysis and interpretation of these downward propagating subsurface temperature anomalies in terms of surface climate. Proper determination of the steady-state geothermal regime is therefore crucial because it is the reference against which climate-induced subsurface temperature anomalies are estimated. Here, we examine the effects of data noise on the determination of the steady-state geothermal regime of the subsurface and the subsequent impact on estimates of ground surface temperature (GST) history and heat gain. We carry out a series of Monte Carlo experiments using 1000 Gaussian noise realizations and depth sections of 100 and 200 m as for steady-state estimates depth intervals, as well as a range of data sampling intervals from 10 m to 0.02 m. Results indicate that typical uncertainties for 50 year averages are on the order of ±0.02 K for the most recent 100 year period. These uncertainties grow with decreasing sampling intervals, reaching about ±0.1 K for a 10 m sampling interval under identical conditions and target period. Uncertainties increase for progressively older periods, reaching ±0.3 K at 500 years before present for a 10 m sampling interval. The uncertainties in reconstructed GST histories for the Northern Hemisphere for the most recent 50 year period can reach a maximum of ±0.5 K in some areas. We suggest that continuous logging should be the preferred approach when measuring geothermal data for climate reconstructions, and that for those using the International Heat Flow Commission database for borehole climatology, the steady-state thermal conditions should be estimated from boreholes as deep as possible and using a large fitting depth range (∼100 m). (letter)

  8. Working Capital Management Policies and Returns of Listed Manufacturing Firms in Ghana

    Directory of Open Access Journals (Sweden)

    Adam Anokye M.

    2017-06-01

    Full Text Available This study sought to determine the effects aggressive/conservative current asset investment and financing policies have on firms′ return for six manufacturing firms listed at Ghana Stock Exchange for a period of 2000-2013. Data were obtained from the annual reports of the firms and the Ghana Stock Exchange. The study adopted longitudinal explanatory non-experimental research design applied to dynamic panel ARDL framework in analyzing the data. The results revealed that the current asset investment and financing policies have highly significant positive effects on returns to equity holders in the long-run. The empirical evidence suggests that conservative current asset investment policies increase firms return while conservative financing policies yields negative returns. The study therefore would enable finance managers to be able to fashion out the appropriate working capital management policies. A firm pursuing conservative current asset investment policy should balance it with aggressive current asset financing policy in order to enhance profitability and create value for their investors.

  9. Agroforestry versus farm mosaic systems - Comparing land-use efficiency, economic returns and risks under climate change effects.

    Science.gov (United States)

    Paul, Carola; Weber, Michael; Knoke, Thomas

    2017-06-01

    Increasing land-use conflicts call for the development of land-use systems that reconcile agricultural production with the provisioning of multiple ecosystem services, including climate change mitigation. Agroforestry has been suggested as a global solution to increase land-use efficiency, while reducing environmental impacts and economic risks for farmers. Past research has often focused on comparing tree-crop combinations with agricultural monocultures, but agroforestry has seldom been systematically compared to other forms of land-use diversification, including a farm mosaic. This form of diversification mixes separate parcels of different land uses within the farm. The objective of this study was to develop a modelling approach to compare the performance of the agroforestry and farm mosaic diversification strategies, accounting for tree-crop interaction effects and economic and climate uncertainty. For this purpose, Modern Portfolio Theory and risk simulation were coupled with the process-based biophysical simulation model WaNuLCAS 4.0. For an example application, we used data from a field trial in Panama. The results show that the simulated agroforestry systems (Taungya, alley cropping and border planting) could outperform a farm mosaic approach in terms of cumulative production and return. Considering market and climate uncertainty, agroforestry showed an up to 21% higher economic return at the same risk level (i.e. standard deviation of economic returns). Farm compositions with large shares of land allocated to maize cultivation were also more severely affected by an increasing drought frequency in terms of both risks and returns. Our study demonstrates that agroforestry can be an economically efficient diversification strategy, but only if the design allows for economies of scope, beneficial interactions between trees and crops and higher income diversification compared to a farm mosaic. The modelling approach can make an important contribution to support

  10. 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.

  11. The uncertainty of reference standards--a guide to understanding factors impacting uncertainty, uncertainty calculations, and vendor certifications.

    Science.gov (United States)

    Gates, Kevin; Chang, Ning; Dilek, Isil; Jian, Huahua; Pogue, Sherri; Sreenivasan, Uma

    2009-10-01

    Certified solution standards are widely used in forensic toxicological, clinical/diagnostic, and environmental testing. Typically, these standards are purchased as ampouled solutions with a certified concentration. Vendors present concentration and uncertainty differently on their Certificates of Analysis. Understanding the factors that impact uncertainty and which factors have been considered in the vendor's assignment of uncertainty are critical to understanding the accuracy of the standard and the impact on testing results. Understanding these variables is also important for laboratories seeking to comply with ISO/IEC 17025 requirements and for those preparing reference solutions from neat materials at the bench. The impact of uncertainty associated with the neat material purity (including residual water, residual solvent, and inorganic content), mass measurement (weighing techniques), and solvent addition (solution density) on the overall uncertainty of the certified concentration is described along with uncertainty calculations.

  12. 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.

  13. 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

  14. 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.

  15. INDONESIA SHARI'AH COMPLIANCE STOCK RETURN BEHAVIOUR

    Directory of Open Access Journals (Sweden)

    Helma Malini

    2017-04-01

    Full Text Available This study aims to measures the behaviour of Indonesia Shari'ah compliance stock return. The measurement of return behaviour toward volatility will proved the capability of Indonesia Shari'ah compliance toward volatility that happened in Indonesia during the period of observation. Investing in Shari'ah compliance is quite different than investing in conventional stock which followed the capital market set of rules and law, Shari'ah compliance follows not only the capital market set of laws and but also the Islamic principles of principles. Most of the previous studies examine issues related to the conventional stocks and market. The present study take one step further by investigating issue related to Shari'ah compliance instrument. In the case of Shari'ah stock price in Indonesia, the dynamics volatility of the stock price can be minimized by taking an integrated screening process to the listed company, as precautions steps toward volatility

  16. Experiences and concerns about 'returning to work' for women breast cancer survivors: a literature review.

    Science.gov (United States)

    Tiedtke, Corine; de Rijk, Angelique; Dierckx de Casterlé, Bernadette; Christiaens, Marie-Rose; Donceel, Peter

    2010-07-01

    To explore how female breast cancer patients experience work incapacity during the treatment and return-to-work phases and how interactions between patients and stakeholders affect this experience. Database search for full text articles published between January 1995 and January 2008 that focused on employed female breast cancer patients, factors related to work incapacity, and returning to work. Only results based on self-report data were included. Studies focusing on treatment, financial factors, rate of return, or absence were excluded. Six articles met the inclusion criteria. Women with breast cancer receive varied reactions but little advice about returning to work. Women were primarily concerned with disclosing the diagnosis to their employer and to relatives. Uncertainties about physical appearance, ability to work, and possible job loss affected the women's decisions about working during the treatment phase. After treatment, most women wanted to regain their 'normal life', but concentration and arm or fatigue problems potentially interfered. Although supportive work environments were helpful, the individual needs of women differed. Employers and employees need to find a balance in defining accommodating work. Many women received favourable support, but some reported feeling discriminated against. Many women re-evaluated the role of work in their lives after being confronted with breast cancer. Work adjustments could help women to keep their jobs during illness and recovery. To resolve women's concerns about returning to work, employers, physicians, and insurance institutions should consider increasing and improving communication with breast cancer patients and playing a more active and supportive role. Copyright (c) 2009 John Wiley & Sons, Ltd.

  17. Using genetic algorithm to solve a new multi-period stochastic optimization model

    Science.gov (United States)

    Zhang, Xin-Li; Zhang, Ke-Cun

    2009-09-01

    This paper presents a new asset allocation model based on the CVaR risk measure and transaction costs. Institutional investors manage their strategic asset mix over time to achieve favorable returns subject to various uncertainties, policy and legal constraints, and other requirements. One may use a multi-period portfolio optimization model in order to determine an optimal asset mix. Recently, an alternative stochastic programming model with simulated paths was proposed by Hibiki [N. Hibiki, A hybrid simulation/tree multi-period stochastic programming model for optimal asset allocation, in: H. Takahashi, (Ed.) The Japanese Association of Financial Econometrics and Engineering, JAFFE Journal (2001) 89-119 (in Japanese); N. Hibiki A hybrid simulation/tree stochastic optimization model for dynamic asset allocation, in: B. Scherer (Ed.), Asset and Liability Management Tools: A Handbook for Best Practice, Risk Books, 2003, pp. 269-294], which was called a hybrid model. However, the transaction costs weren't considered in that paper. In this paper, we improve Hibiki's model in the following aspects: (1) The risk measure CVaR is introduced to control the wealth loss risk while maximizing the expected utility; (2) Typical market imperfections such as short sale constraints, proportional transaction costs are considered simultaneously. (3) Applying a genetic algorithm to solve the resulting model is discussed in detail. Numerical results show the suitability and feasibility of our methodology.

  18. 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...

  19. 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.

  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. Does the central bank directly respond to output and 
inflation uncertainties in Turkey?

    Directory of Open Access Journals (Sweden)

    Pelin Öge Güney

    2016-06-01

    Full Text Available This paper investigates the role of inflation and output uncertainties on monetary policy rules in Turkey for the period 2002:01–2014:02. In the literature it is suggested that uncertainty is a key element in monetary policy, hence empirical models of monetary policy should regard to uncertainty. In this study, we estimate a forward-looking monetary reaction function of the Central Bank of the Republic of Turkey (CBRT. In addition to inflation and output gap variables, our reaction function also includes both the inflation and output growth uncertainties. Our results suggest that the Central Bank of the Republic of Turkey (CBRT concerns with mainly price stability and significantly responds to inflation and growth uncertainties.

  2. SPRT Calibration Uncertainties and Internal Quality Control at a Commercial SPRT Calibration Facility

    Science.gov (United States)

    Wiandt, T. J.

    2008-06-01

    The Hart Scientific Division of the Fluke Corporation operates two accredited standard platinum resistance thermometer (SPRT) calibration facilities, one at the Hart Scientific factory in Utah, USA, and the other at a service facility in Norwich, UK. The US facility is accredited through National Voluntary Laboratory Accreditation Program (NVLAP), and the UK facility is accredited through UKAS. Both provide SPRT calibrations using similar equipment and procedures, and at similar levels of uncertainty. These uncertainties are among the lowest available commercially. To achieve and maintain low uncertainties, it is required that the calibration procedures be thorough and optimized. However, to minimize customer downtime, it is also important that the instruments be calibrated in a timely manner and returned to the customer. Consequently, subjecting the instrument to repeated calibrations or extensive repeated measurements is not a viable approach. Additionally, these laboratories provide SPRT calibration services involving a wide variety of SPRT designs. These designs behave differently, yet predictably, when subjected to calibration measurements. To this end, an evaluation strategy involving both statistical process control and internal consistency measures is utilized to provide confidence in both the instrument calibration and the calibration process. This article describes the calibration facilities, procedure, uncertainty analysis, and internal quality assurance measures employed in the calibration of SPRTs. Data will be reviewed and generalities will be presented. Finally, challenges and considerations for future improvements will be discussed.

  3. Assessing measurement uncertainty in meteorology in urban environments

    International Nuclear Information System (INIS)

    Curci, S; Lavecchia, C; Frustaci, G; Pilati, S; Paganelli, C; Paolini, R

    2017-01-01

    Measurement uncertainty in meteorology has been addressed in a number of recent projects. In urban environments, uncertainty is also affected by local effects which are more difficult to deal with than for synoptic stations. In Italy, beginning in 2010, an urban meteorological network (Climate Network ® ) was designed, set up and managed at national level according to high metrological standards and homogeneity criteria to support energy applications. The availability of such a high-quality operative automatic weather station network represents an opportunity to investigate the effects of station siting and sensor exposure and to estimate the related measurement uncertainty. An extended metadata set was established for the stations in Milan, including siting and exposure details. Statistical analysis on an almost 3-year-long operational period assessed network homogeneity, quality and reliability. Deviations from reference mean values were then evaluated in selected low-gradient local weather situations in order to investigate siting and exposure effects. In this paper the methodology is depicted and preliminary results of its application to air temperature discussed; this allowed the setting of an upper limit of 1 °C for the added measurement uncertainty at the top of the urban canopy layer. (paper)

  4. Assessing measurement uncertainty in meteorology in urban environments

    Science.gov (United States)

    Curci, S.; Lavecchia, C.; Frustaci, G.; Paolini, R.; Pilati, S.; Paganelli, C.

    2017-10-01

    Measurement uncertainty in meteorology has been addressed in a number of recent projects. In urban environments, uncertainty is also affected by local effects which are more difficult to deal with than for synoptic stations. In Italy, beginning in 2010, an urban meteorological network (Climate Network®) was designed, set up and managed at national level according to high metrological standards and homogeneity criteria to support energy applications. The availability of such a high-quality operative automatic weather station network represents an opportunity to investigate the effects of station siting and sensor exposure and to estimate the related measurement uncertainty. An extended metadata set was established for the stations in Milan, including siting and exposure details. Statistical analysis on an almost 3-year-long operational period assessed network homogeneity, quality and reliability. Deviations from reference mean values were then evaluated in selected low-gradient local weather situations in order to investigate siting and exposure effects. In this paper the methodology is depicted and preliminary results of its application to air temperature discussed; this allowed the setting of an upper limit of 1 °C for the added measurement uncertainty at the top of the urban canopy layer.

  5. A coupled stochastic inverse-management framework for dealing with nonpoint agriculture pollution under groundwater parameter uncertainty

    Science.gov (United States)

    Llopis-Albert, Carlos; Palacios-Marqués, Daniel; Merigó, José M.

    2014-04-01

    In this paper a methodology for the stochastic management of groundwater quality problems is presented, which can be used to provide agricultural advisory services. A stochastic algorithm to solve the coupled flow and mass transport inverse problem is combined with a stochastic management approach to develop methods for integrating uncertainty; thus obtaining more reliable policies on groundwater nitrate pollution control from agriculture. The stochastic inverse model allows identifying non-Gaussian parameters and reducing uncertainty in heterogeneous aquifers by constraining stochastic simulations to data. The management model determines the spatial and temporal distribution of fertilizer application rates that maximizes net benefits in agriculture constrained by quality requirements in groundwater at various control sites. The quality constraints can be taken, for instance, by those given by water laws such as the EU Water Framework Directive (WFD). Furthermore, the methodology allows providing the trade-off between higher economic returns and reliability in meeting the environmental standards. Therefore, this new technology can help stakeholders in the decision-making process under an uncertainty environment. The methodology has been successfully applied to a 2D synthetic aquifer, where an uncertainty assessment has been carried out by means of Monte Carlo simulation techniques.

  6. Distribution of Depositors’ Return and The Income Smoothing Hypothesis by Malaysian Islamic Banks

    Directory of Open Access Journals (Sweden)

    Zunaidah Sulong

    2018-01-01

    Full Text Available The paper aims to examine whether Malaysian Islamic banks carry out income smoothing with regards to their distribution of depositors’ return. The paper also examines the extent Malaysian Islamic banks engage earnings and capital management in their distribution of depositors’ return. This empirical study uses balanced panel data from 16 Malaysian Islamic banks, for the period 2008-2012. The regression model is estimated using random effects specifications. The findings indicate that the earnings before tax, zakat, and provision have a positive but insignificant effect on distribution of depositors’ return (DDR whilst the total capital before provision has a positive and significant effect on the DDR. These findings suggest that Islamic banks carry out income smoothing on the distribution of depositors’ return via capital management. Islamic banks also smooth their earnings through distribution of depositors’ return to avoid earnings troughs when earnings are poor. The findings shows prudence exercise among Malaysian Islamic banks with the objectives of mitigating displaced commercial risk (DCR, which involves massive withdrawal and bank runs risks.

  7. Agriculture-driven deforestation in the tropics from 1990-2015: emissions, trends and uncertainties

    Science.gov (United States)

    Carter, Sarah; Herold, Martin; Avitabile, Valerio; de Bruin, Sytze; De Sy, Veronique; Kooistra, Lammert; Rufino, Mariana C.

    2018-01-01

    Limited data exists on emissions from agriculture-driven deforestation, and available data are typically uncertain. In this paper, we provide comparable estimates of emissions from both all deforestation and agriculture-driven deforestation, with uncertainties for 91 countries across the tropics between 1990 and 2015. Uncertainties associated with input datasets (activity data and emissions factors) were used to combine the datasets, where most certain datasets contribute the most. This method utilizes all the input data, while minimizing the uncertainty of the emissions estimate. The uncertainty of input datasets was influenced by the quality of the data, the sample size (for sample-based datasets), and the extent to which the timeframe of the data matches the period of interest. Area of deforestation, and the agriculture-driver factor (extent to which agriculture drives deforestation), were the most uncertain components of the emissions estimates, thus improvement in the uncertainties related to these estimates will provide the greatest reductions in uncertainties of emissions estimates. Over the period of the study, Latin America had the highest proportion of deforestation driven by agriculture (78%), and Africa had the lowest (62%). Latin America had the highest emissions from agriculture-driven deforestation, and these peaked at 974 ± 148 Mt CO2 yr-1 in 2000-2005. Africa saw a continuous increase in emissions between 1990 and 2015 (from 154 ± 21-412 ± 75 Mt CO2 yr-1), so mitigation initiatives could be prioritized there. Uncertainties for emissions from agriculture-driven deforestation are ± 62.4% (average over 1990-2015), and uncertainties were highest in Asia and lowest in Latin America. Uncertainty information is crucial for transparency when reporting, and gives credibility to related mitigation initiatives. We demonstrate that uncertainty data can also be useful when combining multiple open datasets, so we recommend new data

  8. The return to work discussion: a qualitative study of the line manager conversation about return to work and the development of an educational programme.

    Science.gov (United States)

    Cohen, Debbie; Allen, Joanna; Rhydderch, Melody; Aylward, Mansel

    2012-07-01

    To investigate the conversation between line manager and employee about return to work to inform the development of an online interactive educational programme for line managers to improve the effectiveness of their discussions. An inductive qualitative approach, using the principles of action research and motivational interviewing were adopted. The results informed the development of the educational programme for line managers. Middle grade line managers in a large public services employer in the UK. Four discussion groups were conducted over a period of 8 months. Line managers explored the challenges of the return to work interview, analysed their interactions with employees and constructed the content of an educational programme. Multiple methods were used to build engagement with participants, including video and role-play. Nine line managers were recruited across 3 business areas. Managers recognised that their conversations focused on the organisations' policies and procedures and the outcome, rather than the interaction. They recognised the strength of shifting style to shared decision-making and guidance rather than process and instruction. These communication strategies were depicted in the educational programme. The content and flow of the return to work discussion is of high importance and influences employee behaviour and return to work outcomes.

  9. 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%

  10. 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%

  11. 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

  12. Risk, unexpected uncertainty, and estimation uncertainty: Bayesian learning in unstable settings.

    Directory of Open Access Journals (Sweden)

    Elise Payzan-LeNestour

    Full Text Available Recently, evidence has emerged that humans approach learning using Bayesian updating rather than (model-free reinforcement algorithms in a six-arm restless bandit problem. Here, we investigate what this implies for human appreciation of uncertainty. In our task, a Bayesian learner distinguishes three equally salient levels of uncertainty. First, the Bayesian perceives irreducible uncertainty or risk: even knowing the payoff probabilities of a given arm, the outcome remains uncertain. Second, there is (parameter estimation uncertainty or ambiguity: payoff probabilities are unknown and need to be estimated. Third, the outcome probabilities of the arms change: the sudden jumps are referred to as unexpected uncertainty. We document how the three levels of uncertainty evolved during the course of our experiment and how it affected the learning rate. We then zoom in on estimation uncertainty, which has been suggested to be a driving force in exploration, in spite of evidence of widespread aversion to ambiguity. Our data corroborate the latter. We discuss neural evidence that foreshadowed the ability of humans to distinguish between the three levels of uncertainty. Finally, we investigate the boundaries of human capacity to implement Bayesian learning. We repeat the experiment with different instructions, reflecting varying levels of structural uncertainty. Under this fourth notion of uncertainty, choices were no better explained by Bayesian updating than by (model-free reinforcement learning. Exit questionnaires revealed that participants remained unaware of the presence of unexpected uncertainty and failed to acquire the right model with which to implement Bayesian updating.

  13. Working after a stroke: survivors' experiences and perceptions of barriers to and facilitators of the return to paid employment.

    Science.gov (United States)

    Alaszewski, Andy; Alaszewski, Helen; Potter, Jonathan; Penhale, Bridget

    2007-12-30

    This paper examines respondents' relationship with work following a stroke and explores their experiences including the perceived barriers to and facilitators of a return to employment. Our qualitative study explored the experiences and recovery of 43 individuals under 60 years who had survived a stroke. Participants, who had experienced a first stroke less than three months before and who could engage in in-depth interviews, were recruited through three stroke services in South East England. Each participant was invited to take part in four interviews over an 18-month period and to complete a diary for one week each month during this period. At the time of their stroke a minority of our sample (12, 28% of the original sample) were not actively involved in the labour market and did not return to the work during the period that they were involved in the study. Of the 31 participants working at the time of the stroke, 13 had not returned to work during the period that they were involved in the study, six returned to work after three months and nine returned in under three months and in some cases virtually immediately after their stroke. The participants in our study all valued work and felt that working, especially in paid employment, was more desirable than not working. The participants who were not working at the time of their stroke or who had not returned to work during the period of the study also endorsed these views. However they felt that there were a variety of barriers and practical problems that prevented them working and in some cases had adjusted to a life without paid employment. Participants' relationship with work was influenced by barriers and facilitators. The positive valuations of work were modified by the specific context of stroke, for some participants work was a cause of stress and therefore potentially risky, for others it was a way of demonstrating recovery from stroke. The value and meaning varied between participants and this variation

  14. 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...

  15. 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

  16. 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.

  17. [Influence of Uncertainty and Uncertainty Appraisal on Self-management in Hemodialysis Patients].

    Science.gov (United States)

    Jang, Hyung Suk; Lee, Chang Suk; Yang, Young Hee

    2015-04-01

    This study was done to examine the relation of uncertainty, uncertainty appraisal, and self-management in patients undergoing hemodialysis, and to identify factors influencing self-management. A convenience sample of 92 patients receiving hemodialysis was selected. Data were collected using a structured questionnaire and medical records. The collected data were analyzed using descriptive statistics, t-test, ANOVA, Pearson correlations and multiple regression analysis with the SPSS/WIN 20.0 program. The participants showed a moderate level of uncertainty with the highest score being for ambiguity among the four uncertainty subdomains. Scores for uncertainty danger or opportunity appraisals were under the mid points. The participants were found to perform a high level of self-management such as diet control, management of arteriovenous fistula, exercise, medication, physical management, measurements of body weight and blood pressure, and social activity. The self-management of participants undergoing hemodialysis showed a significant relationship with uncertainty and uncertainty appraisal. The significant factors influencing self-management were uncertainty, uncertainty opportunity appraisal, hemodialysis duration, and having a spouse. These variables explained 32.8% of the variance in self-management. The results suggest that intervention programs to reduce the level of uncertainty and to increase the level of uncertainty opportunity appraisal among patients would improve the self-management of hemodialysis patients.

  18. 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

  19. 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.

  20. Market Returns and Weak-Form Efficiency: the case of the Ghana Stock Exchange

    OpenAIRE

    Frimpong, Joseph Magnus; Oteng-Abayie, Eric Fosu

    2007-01-01

    This paper examines the weak-form efficient market hypothesis (EMH) in the case of the Ghana Stock Exchange (GSE) an emerging market. Daily returns from the Databank Stock Index (DSI) over a 5-year period 1999-2004 were used for the exercise. Random walk (RW) and GARCH(1,1) models are used as the basis for our analysis. The GSE DSI returns series exhibit volatility clustering, an indication of inefficiency on the GSE. The weak-form efficient market (random walk) hypothesis was rejected for t...

  1. The Tail Exponent for Stock Returns in Bursa Malaysia for 2003-2008

    Science.gov (United States)

    Rusli, N. H.; Gopir, G.; Usang, M. D.

    2010-07-01

    A developed discipline of econophysics that has been introduced is exhibiting the application of mathematical tools that are usually applied to the physical models for the study of financial models. In this study, an analysis of the time series behavior of several blue chip and penny stock companies in Main Market of Bursa Malaysia has been performed. Generally, the basic quantity being used is the relative price changes or is called the stock price returns, contains daily-sampled data from the beginning of 2003 until the end of 2008, containing 1555 trading days recorded. The aim of this paper is to investigate the tail exponent in tails of the distribution for blue chip stocks and penny stocks financial returns in six years period. By using a standard regression method, it is found that the distribution performed double scaling on the log-log plot of the cumulative probability of the normalized returns. Thus we calculate α for a small scale return as well as large scale return. Based on the result obtained, it is found that the power-law behavior for the probability density functions of the stock price absolute returns P(z)˜z-α with values lying inside and outside the Lévy stable regime with values α>2. All the results were discussed in detail.

  2. Dependence between Stock Returns of Italian Banks and the Sovereign Risk

    Directory of Open Access Journals (Sweden)

    Fabrizio Durante

    2017-06-01

    Full Text Available We analyze the interdependence between the government yield spread and stock returns of the banking sector in Italy during the years 2003–2015. In a first step, we find that the Spearman’s rank correlation between the yield spread and the Italian banking system changed significantly after September 2008. According to this finding, we split the time window in two sub-periods. While we show that the dependence between the banking industry and changes in the yield spread increased significantly in the second time interval, we find no contagion effects from changes in the yield spread to returns of the banking system.

  3. Uncertainty and control in the context of a category-five tornado.

    Science.gov (United States)

    Afifi, Walid A; Afifi, Tamara D; Merrill, Annie

    2014-10-01

    The purpose of this qualitative descriptive study was to illuminate the experience and management of uncertainty during a natural disaster. Interviews were conducted with 26 survivors of a category-five tornado that entirely demolished the small, rural town of Greensburg, Kansas. Three primary themes were found in the survivors' accounts. First, the survivors experienced rapidly shifting levels and kinds of uncertainty as they proceeded through the stages of the disaster. Second, the fluidity of much-needed information added to uncertainty. Third, the feeling of lack of control over outcomes of the disaster and its aftermath was pervasive and was often managed through reliance on communal coping. Recommendations for disaster-related intervention programs are suggested. © 2014 Wiley Periodicals, Inc.

  4. A review of the uncertainties in the assessment of radiological consequences of spent nuclear fuel disposal

    International Nuclear Information System (INIS)

    Wiborgh, M.; Elert, M.; Hoeglund, L.O.; Jones, C.; Grundfelt, B.; Skagius, K.; Bengtsson, A.

    1992-06-01

    Radioactive waste disposal systems for spent nuclear fuel are designed to isolate the radioactive waste from the human environment for long period of time. The isolation is provided by a combination of engineered and natural barriers. Safety assessments are performed to describe and quantify the performance of the individual barriers and the disposal system over long-term periods. These assessments will always be associated with uncertainties. Uncertainties can originate from the variability of natural systems and will also be introduced in the predictive modelling performed to quantitatively evaluate the behaviour of the disposal system as a consequence of the incomplete knowledge about the governing processes. Uncertainties in safety assessments can partly be reduced by additional measurements and research. The aim of this study has been to identify uncertainties in assessments of radiological consequences from the disposal of spent nuclear fuel based on the Swedish KBS-3 concept. The identified uncertainties have been classified with respect to their origin, i.e. in conceptual, modelling and data uncertainties. The possibilities to reduce the uncertainties are also commented upon. In assessments it is important to decrease uncertainties which are of major importance for the performance of the disposal system. These could to some extent be identified by uncertainty analysis. However, conceptual uncertainties and some type of model uncertainties are difficult to evaluate. To be able to decrease uncertainties in conceptual models, it is essential that the processes describing and influencing the radionuclide transport in the engineered and natural barriers are sufficiently understood. In this study a qualitative approach has been used. The importance of different barriers and processes are indicated by their influence on the release of some representative radionuclides. (122 refs.) (au)

  5. County-Level Climate Uncertainty for Risk Assessments: Volume 1.

    Energy Technology Data Exchange (ETDEWEB)

    Backus, George A.; Lowry, Thomas Stephen; Jones, Shannon M; Walker, La Tonya Nicole; Roberts, Barry L; Malczynski, Leonard A.

    2017-06-01

    This report uses the CMIP5 series of climate model simulations to produce country- level uncertainty distributions for use in socioeconomic risk assessments of climate change impacts. It provides appropriate probability distributions, by month, for 169 countries and autonomous-areas on temperature, precipitation, maximum temperature, maximum wind speed, humidity, runoff, soil moisture and evaporation for the historical period (1976-2005), and for decadal time periods to 2100. It also provides historical and future distributions for the Arctic region on ice concentration, ice thickness, age of ice, and ice ridging in 15-degree longitude arc segments from the Arctic Circle to 80 degrees latitude, plus two polar semicircular regions from 80 to 90 degrees latitude. The uncertainty is meant to describe the lack of knowledge rather than imprecision in the physical simulation because the emphasis is on unfalsified risk and its use to determine potential socioeconomic impacts. The full report is contained in 27 volumes.

  6. Optimization of the GSFC TROPOZ DIAL retrieval using synthetic lidar returns and ozonesondes - Part 1: Algorithm validation

    Science.gov (United States)

    Sullivan, J. T.; McGee, T. J.; Leblanc, T.; Sumnicht, G. K.; Twigg, L. W.

    2015-10-01

    The main purpose of the NASA Goddard Space Flight Center TROPospheric OZone DIfferential Absorption Lidar (GSFC TROPOZ DIAL) is to measure the vertical distribution of tropospheric ozone for science investigations. Because of the important health and climate impacts of tropospheric ozone, it is imperative to quantify background photochemical ozone concentrations and ozone layers aloft, especially during air quality episodes. For these reasons, this paper addresses the necessary procedures to validate the TROPOZ retrieval algorithm and confirm that it is properly representing ozone concentrations. This paper is focused on ensuring the TROPOZ algorithm is properly quantifying ozone concentrations, and a following paper will focus on a systematic uncertainty analysis. This methodology begins by simulating synthetic lidar returns from actual TROPOZ lidar return signals in combination with a known ozone profile. From these synthetic signals, it is possible to explicitly determine retrieval algorithm biases from the known profile. This was then systematically performed to identify any areas that need refinement for a new operational version of the TROPOZ retrieval algorithm. One immediate outcome of this exercise was that a bin registration error in the correction for detector saturation within the original retrieval was discovered and was subsequently corrected for. Another noticeable outcome was that the vertical smoothing in the retrieval algorithm was upgraded from a constant vertical resolution to a variable vertical resolution to yield a statistical uncertainty of exercise was quite successful.

  7. 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...

  8. 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

  9. 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

  10. Pengaruh Dividen Inisiasi dan Dividen Omisi terhadap Return Saham di Bursa Efek Indonesia

    Directory of Open Access Journals (Sweden)

    Azizah Ayu Sielvia

    2011-03-01

    Full Text Available The objective of this study is to determine the effect of dividend initiations and dividend omission of stock returns in Indonesia Stock Exchange (BEI. Variables in this study consist of dividends, dividend announcements, and a significant stock return on dividend announcement reflected the presence of abnormal return during the event period. This study employs the company's shares listed on Indonesia Stock Exchange and are actively traded. Samples used as many as 50 companies, where 37 companies as a dividend initiation and 13 companies as a dividend omission. The sample selection was done by purposive sampling method that is research based on certain criteria. Results of analysis testing the effect of the abnormal return of dividend announcements indicate a significant influence. Announcements of dividend initiations have significant positive influence, while the announcements of dividend omissions have significant negative market reaction. That means the announcement of dividend initiations have a signal or a specific information content that causes the market to react more than normal state of the information, while the announcement of dividend omissions affect investors to remove their stock price moves down or there is a significant abnormal return.Keywords: dividend initiation, dividend omission, dividend announcement, stock return

  11. The Use of Risk and Return for Testing the Stability of Stock Markets

    Directory of Open Access Journals (Sweden)

    Viorica Chirilă

    2014-04-01

    Full Text Available The European Central Bank stipulates that a financial system is stable if the financial risks are evaluated and rewarded correctly and if the economic and financial shocks are absorbed. When analyzing the return and volatility of the stock exchanges we may ascertain that a stock exchange is stable if there is a connection between return and volatility and if the shocks determined by the new positive and negative information do not cause significant changes of the volatility. We took into consideration the values of the indices of stock markets from Holland (AEX, Belgium (BEL, Romania (BET, Hungary (BUX, Germany (DAX, France (CAC, Czech Republic (PX, Slovakia (SAX, Austria (ATX, Estonia (OMXT, Latvia (OMXR and Lithuania (OMXV. In order to test the relationship between return-volatility and volatility asymmetry we estimated a GJR-GARCH-M model. The results confirm the lack of existence of a correlation between return and volatility for the entire period under analysis and the existence of the volatility asymmetry.

  12. Abnormal stock market returns to announcements of M&A banking deals in Greece 1996-2013

    Directory of Open Access Journals (Sweden)

    Anastasios KARAMANOS

    2015-06-01

    Full Text Available This study has undertaken a comprehensive empirical analysis of the wealth effects of bank M&As in Greece over the period 1996-2013. The purpose is to measure the performance of merger participants over the acquisition period as a deviation of how shareholders’ actual returns differ from expected returns conditional on the particular process of M&A. The authors develop a conceptual framework that integrates theoretical perspectives from economics, finance, organization theory, strategic management and human resource management to offer a broader process-oriented integrative model of the empirical evidence and theories suggested to explain acquisitions. The empirical analysis reports insignificant abnormal gains for acquiring banks, significant positive abnormal returns at 7,44% for acquired banks, and 2,91% positive abnormal returns for the combined entity, in the event window [-10;+1]. The findings indicate that, on average, the Greek bank mergers neither create nor destroy shareholder wealth. This result is consistent with the findings of other Greek event studies and the bulk of US and European event studies on M&A wealth effects. On average, acquired firm shareholders gain at the expense of the acquiring firm and market value of the combined entity appears to have little improvement around the announcement of the transaction. The conceptual framework explicitly describes that wealth effects of bank M&As in Greece over the period 1996-2013 may be a result of macroeconomic theory and perfectly competitive market, lack of strategic relatedness and synergy realization, managerial hubris, or unethical behavior of managers derived from expense preference approach of agency theory.

  13. The Determinant Factors Of Sectoral Stock Return In Bullish And Bearish Condition At Indonesian Capital Market

    Directory of Open Access Journals (Sweden)

    Defrizal

    2015-07-01

    Full Text Available Abstract this study aims to explain determinant factors of sectoral stock return in bullish and bearish condition at Indonesian capital market. This study used a multi-factor asset pricing model with sectoral stock return as the dependent variable and stock market return interest rates and exchange rate as independent variables. The Identification of stock market condition by using a Markov Switching Models which are also used as the basis for segmenting the data into bullish and bearish conditions. Estimates of the model used the robust least square method. This study used data from Indonesian Stock Exchange to the observation period from January 1996 to December 2013. The results of this study were 1 simultaneously stock market return interest rates and exchange rate affected the sectoral stock return in bullish and bearish condition. 2 Partially the stock market return positively effect and is as a main factor in determining the sectoral stock return in all industries in either bullish condition or bearish condition while the effect of the interest rates and exchange rate do not consistently affect the sectoral stock return in different industries and market conditions.

  14. Uncertainty in prediction and simulation of flow in sewer systems

    DEFF Research Database (Denmark)

    Breinholt, Anders

    the uncertainty in the state variables. Additionally the observation noise is accounted for by a separate observation noise term. This approach is also referred to as stochastic grey-box modelling. A state dependent diffusion term was developed using a Lamperti transformation of the states, and implemented...... performance beyond the one-step. The reliability was satisfied for the one-step prediction but were increasingly biased as the prediction horizon was expanded, particularly in rainy periods. GLUE was applied for estimating uncertainty in such a way that the selection of behavioral parameter sets continued....... Conversely the parameter estimates of the stochastic approach are physically meaningful. This thesis has contributed to developing simplified rainfall-runoff models that are suitable for model predictive control of urban drainage systems that takes uncertainty into account....

  15. An Efficient Approach for Mars Sample Return Using Emerging Commercial Capabilities.

    Science.gov (United States)

    Gonzales, Andrew A; Stoker, Carol R

    2016-06-01

    Mars Sample Return is the highest priority science mission for the next decade as recommended by the 2011 Decadal Survey of Planetary Science [1]. This article presents the results of a feasibility study for a Mars Sample Return mission that efficiently uses emerging commercial capabilities expected to be available in the near future. The motivation of our study was the recognition that emerging commercial capabilities might be used to perform Mars Sample Return with an Earth-direct architecture, and that this may offer a desirable simpler and lower cost approach. The objective of the study was to determine whether these capabilities can be used to optimize the number of mission systems and launches required to return the samples, with the goal of achieving the desired simplicity. All of the major element required for the Mars Sample Return mission are described. Mission system elements were analyzed with either direct techniques or by using parametric mass estimating relationships. The analysis shows the feasibility of a complete and closed Mars Sample Return mission design based on the following scenario: A SpaceX Falcon Heavy launch vehicle places a modified version of a SpaceX Dragon capsule, referred to as "Red Dragon", onto a Trans Mars Injection trajectory. The capsule carries all the hardware needed to return to Earth Orbit samples collected by a prior mission, such as the planned NASA Mars 2020 sample collection rover. The payload includes a fully fueled Mars Ascent Vehicle; a fueled Earth Return Vehicle, support equipment, and a mechanism to transfer samples from the sample cache system onboard the rover to the Earth Return Vehicle. The Red Dragon descends to land on the surface of Mars using Supersonic Retropropulsion. After collected samples are transferred to the Earth Return Vehicle, the single-stage Mars Ascent Vehicle launches the Earth Return Vehicle from the surface of Mars to a Mars phasing orbit. After a brief phasing period, the Earth Return

  16. DAMPAK PEMODERASIAN KOMPONEN ARUS KAS TERHADAP HUBUNGAN LABA AKUNTANSI DENGAN RETURN SAHAM

    Directory of Open Access Journals (Sweden)

    PUTU ARI DHARMA LAKSMI

    2009-07-01

    Full Text Available Accurate information regarding listed companies is crucial tominimize investment risk. This research aims to examine the effect ofaccounting income on stock return, and the effect of cash flow fromoperation, cash flow from investment, and cash flow from financingactivities respectively as moderating variables on the relationshipbetween accounting income and stock return of manufacturer listedon the Jakarta Stock Exchange.There were 161 manufacturing companies listed during 2001to 2005, and 39 of them are selected as sample research usingpurposive sampling method. With 5 year research period, there are195 observations done. Data then are analyzed using multiple linearregressions.Results show that accounting income affect stock returnsignificantly, which is shown by greater value of t count compare to ttable. While cash flow from operation, investment, and financingactivities are not able to moderate relationship between accountingincome and stock return.

  17. 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...

  18. Laboratory Evaluation of Air Flow Measurement Methods for Residential HVAC Returns for New Instrument Standards

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Iain [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Stratton, Chris [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-08-01

    This project improved the accuracy of air flow measurements used in commissioning California heating and air conditioning systems in Title 24 (Building and Appliance Efficiency Standards), thereby improving system performance and efficiency of California residences. The research team at Lawrence Berkeley National Laboratory addressed the issue that typical tools used by contractors in the field to test air flows may not be accurate enough to measure return flows used in Title 24 applications. The team developed guidance on performance of current diagnostics as well as a draft test method for use in future evaluations. The study team prepared a draft test method through ASTM International to determine the uncertainty of air flow measurements at residential heating ventilation and air conditioning returns and other terminals. This test method, when finalized, can be used by the Energy Commission and other entities to specify required accuracy of measurement devices used to show compliance with standards.

  19. 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)

  20. Are Returns to Education on the Decline in Venezuela and Does Mission Sucre Have a Role to Play?

    Science.gov (United States)

    Gonzalez, Naihobe; Oyelere, Ruth Uwaifo

    2011-01-01

    Anecdotal evidence points to a falling standard of living for the educated in Venezuela. During this same period, President Hugo Chavez implemented several education reforms. We focus on a major university education reform known as Mission Sucre and its potential impact on returns to university education. First, we show that returns to education…

  1. Effects of utility demand-side management programs on uncertainty

    International Nuclear Information System (INIS)

    Hirst, E.

    1994-01-01

    Electric utilities face a variety of uncertainties that complicate their long-term resource planning. These uncertainties include future economic and load growths, fuel prices, environmental and economic regulations, performance of existing power plants, cost and availability of purchased power, and the costs and performance of new demand and supply resources. As utilities increasingly turn to demand-side management (DSM) programs to provide resources, it becomes more important to analyze the interactions between these programs and the uncertainties facing utilities. This paper uses a dynamic planning model to quantify the uncertainty effects of supply-only vs DSM + supply resource portfolios. The analysis considers four sets of uncertainties: economic growth, fuel prices, the costs to build new power plants, and the costs to operate DSM programs. The two types of portfolios are tested against these four sets of uncertainties for the period 1990 to 2010. Sensitivity, scenario, and worst-case analysis methods are used. The sensitivity analyses show that the DSM + supply resource portfolio is less sensitive to unanticipated changes in economic growth, fuel prices, and power-plant construction costs than is the supply-only portfolio. The supply-only resource mix is better only with respect to uncertainties about the costs of DSM programs. The base-case analysis shows that including DSM programs in the utility's resource portfolio reduces the net present value of revenue requirements (NPV-RR) by 490 million dollars. The scenario-analysis results show an additional 30 million dollars (6%) in benefits associated with reduction in these uncertainties. In the worst-case analysis, the DSM + supply portfolio again reduces the cost penalty associated with guessing wrong for both cases, when the utility plans for high needs and learns it has low needs and vice versa. 20 refs

  2. The Smoothing Hypothesis, Stock Returns and Risk in Brazil

    Directory of Open Access Journals (Sweden)

    Antonio Lopo Martinez

    2011-01-01

    Full Text Available Income smoothing is defined as the deliberate normalization of income in order to reach a desired trend. If the smoothing causes more information to be reflected in the stock price, it is likely to improve the allocation of resources and can be a critical factor in investment decisions. This study aims to build metrics to determine the degree of smoothing in Brazilian public companies, to classify them as smoothing and non-smoothing companies and additionally to present evidence on the long-term relationship between the smoothing hypothesis and stock return and risk. Using the Economatica and CVM databases, this study focuses on 145 companies in the period 1998-2007. We find that Brazilian smoothers have a smaller degree of systemic risk than non-smoothers. In average terms, the beta of smoothers is significantly lower than non-smoothers. Regarding return, we find that the abnormal annualized returns of smoothers are significantly higher. We confirm differences in the groups by nonparametric and parametric tests in cross section or as time series, indicating that there is a statistically significant difference in performance in the Brazilian market between firms that do and do not engage in smoothing.

  3. 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.

  4. Factors Affecting Stock Returns of Firms Quoted in ISE Market: A Dynamic Panel Data Approach

    Directory of Open Access Journals (Sweden)

    Şebnem Er

    2013-07-01

    Full Text Available Several studies, explaining the factors affecting stock returns, have been published both in developed and developing countries. In many of these papers, either cross-sectional or time series methods have been applied. In this study, Dynamic Panel Data Analysis Methods have been conducted to explain the factors affecting stock returns of 64 manufacturing firms that are continuously quoted in ISE during the period of 2003-2007. The results indicate that stock performance, financial structure, activity and profitability ratios can be used to explain the stock returns as well as the oil prices, economic growth, exchange rate, interest rate, and money supply.

  5. Accounting for downscaling and model uncertainty in fine-resolution seasonal climate projections over the Columbia River Basin

    Science.gov (United States)

    Ahmadalipour, Ali; Moradkhani, Hamid; Rana, Arun

    2018-01-01

    Climate change is expected to have severe impacts on natural systems as well as various socio-economic aspects of human life. This has urged scientific communities to improve the understanding of future climate and reduce the uncertainties associated with projections. In the present study, ten statistically downscaled CMIP5 GCMs at 1/16th deg. spatial resolution from two different downscaling procedures are utilized over the Columbia River Basin (CRB) to assess the changes in climate variables and characterize the associated uncertainties. Three climate variables, i.e. precipitation, maximum temperature, and minimum temperature, are studied for the historical period of 1970-2000 as well as future period of 2010-2099, simulated with representative concentration pathways of RCP4.5 and RCP8.5. Bayesian Model Averaging (BMA) is employed to reduce the model uncertainty and develop a probabilistic projection for each variable in each scenario. Historical comparison of long-term attributes of GCMs and observation suggests a more accurate representation for BMA than individual models. Furthermore, BMA projections are used to investigate future seasonal to annual changes of climate variables. Projections indicate significant increase in annual precipitation and temperature, with varied degree of change across different sub-basins of CRB. We then characterized uncertainty of future projections for each season over CRB. Results reveal that model uncertainty is the main source of uncertainty, among others. However, downscaling uncertainty considerably contributes to the total uncertainty of future projections, especially in summer. On the contrary, downscaling uncertainty appears to be higher than scenario uncertainty for precipitation.

  6. 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...

  7. Bid-Ask Spreads, Trading Volume and Return Volatility: Intraday Evidence from Indian Stock Market

    Directory of Open Access Journals (Sweden)

    Rashmi Ranjan Paital

    2016-01-01

    Full Text Available This paper empirically examines the relationship between stock return volatility, trading volume and bid-ask spread within the scope of mixture of distribution hypothesis (MDH and sequential information arrival hypothesis (SIAH in the Indian stock market using high frequency 5-minute data set over the period of 2 July 2012 to 31 December 2012. This is the first kind of study in India using bid-ask spread as an additional information variable along with trading volume to investigate the relationship with stock return volatility. Our empirical findings provide evidence of a positive contemporaneous relationship between return volatility and trading volume, and also between return volatility and bid-ask spread. Moreover, the results of Granger causality test show that the information content of trading volume and bid-ask spread are useful for predicting stock return volatility. Our results indicate that information arrival to investors tends to follow a sequential rather than a simultaneous process. This finding is consistent with the sequential information arrival hypothesis and contradicts the mixture of distribution hypothesis.

  8. Inflation and Inflation Uncertainty Revisited: Evidence from Egypt

    Directory of Open Access Journals (Sweden)

    Mesbah Fathy Sharaf

    2015-07-01

    Full Text Available The welfare costs of inflation and inflation uncertainty are well documented in the literature and empirical evidence on the link between the two is sparse in the case of Egypt. This paper investigates the causal relationship between inflation and inflation uncertainty in Egypt using monthly time series data during the period January 1974–April 2015. To endogenously control for any potential structural breaks in the inflation time series, Zivot and Andrews (2002 and Clemente–Montanes–Reyes (1998 unit root tests are used. The inflation–inflation uncertainty relation is modeled by the standard two-step approach as well as simultaneously using various versions of the GARCH-M model to control for any potential feedback effects. The analyses explicitly control for the effect of the Economic Reform and Structural Adjustment Program (ERSAP undertaken by the Egyptian government in the early 1990s, which affected inflation rate and its associated volatility. Results show a high degree of inflation–volatility persistence in the response to inflationary shocks. Granger-causality test along with symmetric and asymmetric GARCH-M models indicate a statistically significant bi-directional positive relationship between inflation and inflation uncertainty, supporting both the Friedman–Ball and the Cukierman–Meltzer hypotheses. The findings are robust to the various estimation methods and model specifications. The findings of this paper support the view of adopting inflation-targeting policy in Egypt, after fulfilling its preconditions, to reduce the welfare cost of inflation and its related uncertainties. Monetary authorities in Egypt should enhance the credibility of monetary policy and attempt to reduce inflation uncertainty, which will help lower inflation rates.

  9. 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.

  10. The effects of financial risks on the relationship between earnings and stock returns

    Directory of Open Access Journals (Sweden)

    Mehri Akhavi Babi

    2015-06-01

    Full Text Available This study was conducted to investigate the effects of financial risks on the relationship between earnings per share and stock returns. The statistical population of the study consisted of the companies accepted by Tehran Stock Exchange. According to the conditions for sampling, 65 companies were selected during a period of six years from 2008 to 2013 (i.e., 390 fiscal years, and four hypotheses were set forth to achieve the purposes of the study. The first hypothesis tried to assess the relationship between earnings per share and stock returns. The second, third, and fourth hypotheses investigated the significance of the effects of three financial risks, namely liquidity, credit, and solvency risks on the relationship between earnings per share and stock returns. The hypotheses of the study were tested using linear and multiple regressions. The findings of the study indicated that there was a positive and significant relationship between earnings per share and stock returns. In addition, the results proved that the credit and solvency risks had negative and significant effects on the relationship between earnings per share and stock returns, but the effect of liquidity risk on this relationship was not significant.

  11. Temporal Oculomotor Inhibition of Return and Spatial Facilitation of Return in a Visual Encoding Task

    Directory of Open Access Journals (Sweden)

    Steven G Luke

    2013-07-01

    Full Text Available Oculomotor inhibition of return (O-IOR is an increase in saccade latency prior to an eye movement to a recently fixated location compared to other locations. It has been proposed that this temporal O-IOR may have spatial consequences, facilitating foraging by inhibiting return to previously attended regions. In order to test this possibility, participants viewed arrays of objects and of words while their eye movements were recorded. Temporal O-IOR was observed, with equivalent effects for object and word arrays, indicating that temporal O-IOR is an oculomotor phenomenon independent of array content. There was no evidence for spatial inhibition of return. Instead, spatial facilitation of return was observed: Participants were significantly more likely than chance to make return saccades and to refixate just-visited locations. Further, the likelihood of making a return saccade to an object or word was contingent on the amount of time spent viewing that object or word before leaving it. This suggests that, unlike temporal O-IOR, return probability is influenced by cognitive processing. Taken together, these results are inconsistent with the hypothesis that inhibition of return functions as a foraging facilitator. The results also provide strong evidence for a different oculomotor bias that could serve as a foraging facilitator: saccadic momentum, a tendency to repeat the most recently executed saccade program. We suggest that models of visual attention could incorporate saccadic momentum in place of inhibition of return.

  12. 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.

  13. Propagation of interval and probabilistic uncertainty in cyberinfrastructure-related data processing and data fusion

    CERN Document Server

    Servin, Christian

    2015-01-01

    On various examples ranging from geosciences to environmental sciences, this book explains how to generate an adequate description of uncertainty, how to justify semiheuristic algorithms for processing uncertainty, and how to make these algorithms more computationally efficient. It explains in what sense the existing approach to uncertainty as a combination of random and systematic components is only an approximation, presents a more adequate three-component model with an additional periodic error component, and explains how uncertainty propagation techniques can be extended to this model. The book provides a justification for a practically efficient heuristic technique (based on fuzzy decision-making). It explains how the computational complexity of uncertainty processing can be reduced. The book also shows how to take into account that in real life, the information about uncertainty is often only partially known, and, on several practical examples, explains how to extract the missing information about uncer...

  14. 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…

  15. A new framework for estimating return levels using regional frequency analysis

    Science.gov (United States)

    Winter, Hugo; Bernardara, Pietro; Clegg, Georgina

    2017-04-01

    , we use the regional frequency analysis approach to define homogeneous regions which are affected by the same storms. Extreme value models are then fitted to the data pooled from across a region. We find that this approach leads to more spatially consistent return level estimates with reduced uncertainty bounds.

  16. Evaluating uncertainties in regional climate simulations over South America at the seasonal scale

    Energy Technology Data Exchange (ETDEWEB)

    Solman, Silvina A. [Centro de Investigaciones del Mar y la Atmosfera CIMA/CONICET-UBA, DCAO/FCEN, UMI-IFAECI/CNRS, CIMA-Ciudad Universitaria, Buenos Aires (Argentina); Pessacg, Natalia L. [Centro Nacional Patagonico (CONICET), Puerto Madryn, Chubut (Argentina)

    2012-07-15

    This work focuses on the evaluation of different sources of uncertainty affecting regional climate simulations over South America at the seasonal scale, using the MM5 model. The simulations cover a 3-month period for the austral spring season. Several four-member ensembles were performed in order to quantify the uncertainty due to: the internal variability; the definition of the regional model domain; the choice of physical parameterizations and the selection of physical parameters within a particular cumulus scheme. The uncertainty was measured by means of the spread among individual members of each ensemble during the integration period. Results show that the internal variability, triggered by differences in the initial conditions, represents the lowest level of uncertainty for every variable analyzed. The geographic distribution of the spread among ensemble members depends on the variable: for precipitation and temperature the largest spread is found over tropical South America while for the mean sea level pressure the largest spread is located over the southeastern Atlantic Ocean, where large synoptic-scale activity occurs. Using nudging techniques to ingest the boundary conditions reduces dramatically the internal variability. The uncertainty due to the domain choice displays a similar spatial pattern compared with the internal variability, except for the mean sea level pressure field, though its magnitude is larger all over the model domain for every variable. The largest spread among ensemble members is found for the ensemble in which different combinations of physical parameterizations are selected. The perturbed physics ensemble produces a level of uncertainty slightly larger than the internal variability. This study suggests that no matter what the source of uncertainty is, the geographical distribution of the spread among members of the ensembles is invariant, particularly for precipitation and temperature. (orig.)

  17. Economic crisis and women's labor force return after childbirth: Evidence from South Korea

    Directory of Open Access Journals (Sweden)

    Li Ma

    2014-08-01

    Full Text Available Background: Most research on women's labor force return after childbirth concentrates on industrialized countries in the West; the link between economic swings and mothers' work-return behavior is rarely addressed. This study closes these gaps by focusing on South Korea, a developed society in East Asia that has in recent decades witnessed increases in female labor force participation and dramatic economic ups and downs. This is the first relevant study on South Korea. Objective: This study examines how women's labor force return after childbirth (with and without career interruption and their career prospects upon work return varied before, during, and after the Asian financial crisis in South Korea. Methods: Logistic and hazard regression models were applied to the Korea Labor and Income Panel Study (KLIPS waves 1-10. Results: The study reveals an increase in women's immediate work return after childbirth without career interruption since the 1980s. The Asian financial crisis boosted this immediate return pattern. The implementation of job-protected maternity leave further contributed to this pattern. Women who underwent career interruption at first birth were also more likely to re-enter the labor market during and after the crisis than before. Downward occupational moves were especially common during the period of financial crisis. Conclusions: The results suggest that the Asian financial crisis triggered a noticeable change in women's post-birth work-return behavior. The economic volatility pushed mothers to hold onto their role in the labor force more strongly than before.

  18. Uncertainty as Knowledge: Constraints on Policy Choices Provided by Analysis of Uncertainty

    Science.gov (United States)

    Lewandowsky, S.; Risbey, J.; Smithson, M.; Newell, B. R.

    2012-12-01

    Uncertainty forms an integral part of climate science, and it is often cited in connection with arguments against mitigative action. We argue that an analysis of uncertainty must consider existing knowledge as well as uncertainty, and the two must be evaluated with respect to the outcomes and risks associated with possible policy options. Although risk judgments are inherently subjective, an analysis of the role of uncertainty within the climate system yields two constraints that are robust to a broad range of assumptions. Those constraints are that (a) greater uncertainty about the climate system is necessarily associated with greater expected damages from warming, and (b) greater uncertainty translates into a greater risk of the failure of mitigation efforts. These ordinal constraints are unaffected by subjective or cultural risk-perception factors, they are independent of the discount rate, and they are independent of the magnitude of the estimate for climate sensitivity. The constraints mean that any appeal to uncertainty must imply a stronger, rather than weaker, need to cut greenhouse gas emissions than in the absence of uncertainty.

  19. 26 CFR 20.6018-2 - Returns; person required to file return.

    Science.gov (United States)

    2010-04-01

    ... executor or administrator shall file the return. If there is more than one executor or administrator, the return must be made jointly by all. If there is no executor or administrator appointed, qualified and... decedent situated in the United States is constituted an executor for purposes of the tax (see § 20.2203-1...

  20. 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.

  1. 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...

  2. 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...

  3. Analisis Pengaruh Perubahan Arus Kas dan Laba Akuntansi Terhadap Return Saham pada Perusahaan Berkapitalisasi Besar

    Directory of Open Access Journals (Sweden)

    Azilia Yocelyn

    2012-01-01

    Full Text Available This study aims to examine whether the changes of cash flows and accounting profit, used by investors to make investment decision, reflected in the companies’ stock return. There are four independent variables includes in this study, that is cash flows from operating, investing, and financing activities, as well as accounting profit. The stock return is calculated by using the geometric mean method. Multiple regression analysis is used to examine the data on the top 97 public companies (based on market capitalization catagory listed in Indonesia Stock Exchange for period 2009-2010. The result reveals that accounting profit disclosure markedly affected the stock return. This implies that investors took into account the publication of accounting profit in their decision making. On the other side, the study cannot prove the association of other independent variables to  the stock return.

  4. 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...

  5. Characterization of subjective uncertainty in the 1996 performance assessment for the Waste Isolation Pilot Plant

    International Nuclear Information System (INIS)

    HELTON, JON CRAIG; MARTELL, MARY-ALENA; TIERNEY, MARTIN S.

    2000-01-01

    The 1996 performance assessment (PA) for the Waste Isolation Pilot Plant (WIPP) maintains a separation between stochastic (i.e., aleatory) and subjective (i.e., epistemic) uncertainty, with stochastic uncertainty arising from the possible disruptions that could occur at the WIPP over the 10,000 yr regulatory period specified by the US Environmental Protection Agency (40 CFR 191,40 CFR 194) and subjective uncertainty arising from an inability to uniquely characterize many of the inputs required in the 1996 WIPP PA. The characterization of subjective uncertainty is discussed, including assignment of distributions, uncertain variables selected for inclusion in analysis, correlation control, sample size, statistical confidence on mean complementary cumulative distribution functions, generation of Latin hypercube samples, sensitivity analysis techniques, and scenarios involving stochastic and subjective uncertainty

  6. Characterization of subjective uncertainty in the 1996 performance assessment for the Waste Isolation Pilot Plant

    Energy Technology Data Exchange (ETDEWEB)

    HELTON,JON CRAIG; MARTELL,MARY-ALENA; TIERNEY,MARTIN S.

    2000-05-18

    The 1996 performance assessment (PA) for the Waste Isolation Pilot Plant (WIPP) maintains a separation between stochastic (i.e., aleatory) and subjective (i.e., epistemic) uncertainty, with stochastic uncertainty arising from the possible disruptions that could occur at the WIPP over the 10,000 yr regulatory period specified by the US Environmental Protection Agency (40 CFR 191,40 CFR 194) and subjective uncertainty arising from an inability to uniquely characterize many of the inputs required in the 1996 WIPP PA. The characterization of subjective uncertainty is discussed, including assignment of distributions, uncertain variables selected for inclusion in analysis, correlation control, sample size, statistical confidence on mean complementary cumulative distribution functions, generation of Latin hypercube samples, sensitivity analysis techniques, and scenarios involving stochastic and subjective uncertainty.

  7. Optimal inventory policy in a closed loop supply chain system with multiple periods

    International Nuclear Information System (INIS)

    Sasi Kumar, A.; Natarajan, K.; Ramasubramaniam, Muthu Rathna Sapabathy.; Deepaknallasamy, K.K.

    2017-01-01

    Purpose: This paper aims to model and optimize the closed loop supply chain for maximizing the profit by considering the fixed order quantity inventory policy in various sites at multiple periods. Design/methodology/approach: In forward supply chain, a standard inventory policy can be followed when the product moves from manufacturer, distributer, retailer and customer but the inventory in the reverse supply chain of the product with the similar standard policy is very difficult to manage. This model investigates the standard policy of fixed order quantity by considering the three major types of return-recovery pair such as commercial returns, end- of- use returns, end –of- life returns and their inventory positioning at multiple periods. The model is configured as mixed integer linear programming and solved by IBM ILOG CPLEX OPL studio. Findings: To find the performance of the model a numerical example is considered for a product with three Parts (A which of 2nos, B and C) for 12 multiple periods. The results of the analysis show that the manufacturer can know how much should to be manufacture in multiple periods based on Variations of the demand by adopting the FOQ inventory policy at different sites considering its capacity constraints. In addition, it is important how much of parts should be purchased from the supplier at the given 12 periods. Originality/value: A sensitivity analysis is performed to validate the proposed model two parts. First part of the analysis will focus on the inventory of product and parts and second part of analysis focus on profit of the company. The analysis which provides some insights in to the structure of the model.

  8. Optimal inventory policy in a closed loop supply chain system with multiple periods

    Energy Technology Data Exchange (ETDEWEB)

    Sasi Kumar, A.; Natarajan, K.; Ramasubramaniam, Muthu Rathna Sapabathy.; Deepaknallasamy, K.K.

    2017-07-01

    Purpose: This paper aims to model and optimize the closed loop supply chain for maximizing the profit by considering the fixed order quantity inventory policy in various sites at multiple periods. Design/methodology/approach: In forward supply chain, a standard inventory policy can be followed when the product moves from manufacturer, distributer, retailer and customer but the inventory in the reverse supply chain of the product with the similar standard policy is very difficult to manage. This model investigates the standard policy of fixed order quantity by considering the three major types of return-recovery pair such as commercial returns, end- of- use returns, end –of- life returns and their inventory positioning at multiple periods. The model is configured as mixed integer linear programming and solved by IBM ILOG CPLEX OPL studio. Findings: To find the performance of the model a numerical example is considered for a product with three Parts (A which of 2nos, B and C) for 12 multiple periods. The results of the analysis show that the manufacturer can know how much should to be manufacture in multiple periods based on Variations of the demand by adopting the FOQ inventory policy at different sites considering its capacity constraints. In addition, it is important how much of parts should be purchased from the supplier at the given 12 periods. Originality/value: A sensitivity analysis is performed to validate the proposed model two parts. First part of the analysis will focus on the inventory of product and parts and second part of analysis focus on profit of the company. The analysis which provides some insights in to the structure of the model.

  9. Optimal inventory policy in a closed loop supply chain system with multiple periods

    Directory of Open Access Journals (Sweden)

    SasiKumar A.

    2017-05-01

    Full Text Available Purpose: This paper aims to model and optimize the closed loop supply chain for maximizing the profit by considering the fixed order quantity inventory policy in various sites at multiple periods. Design/methodology/approach: In forward supply chain, a standard inventory policy can be followed when the product moves from manufacturer, distributer, retailer and customer but the inventory in the reverse supply chain of the product with the similar standard policy is very difficult to manage. This model investigates the standard policy of fixed order quantity by considering the three major types of return-recovery pair such as commercial returns, end- of- use returns, end –of- life returns and their inventory positioning at multiple periods.  The model is configured as mixed integer linear programming and solved by IBM ILOG CPLEX OPL studio. Findings: To find the performance of the model a numerical example is considered for a product with three Parts (A which of 2nos, B and C for 12 multiple periods. The results of the analysis show that the manufacturer can know how much should to be manufacture in multiple periods based on Variations of the demand by adopting the FOQ inventory policy at different sites considering its capacity constraints. In addition, it is important how much of parts should be purchased from the supplier at the given 12 periods. Originality/value: A sensitivity analysis is performed to validate the proposed model two parts. First part of the analysis will focus on the inventory of product and parts and second part of analysis focus on profit of the company. The analysis which provides some insights in to the structure of the model.

  10. Return spillovers between white precious metal ETFs: The role of oil, gold, and global equity

    OpenAIRE

    Lau, Marco Chi Keung; Vigne, Samuel A.; Wang, Shixuan; Yarovaya, Larisa

    2017-01-01

    This paper investigates the relationship between white precious metals and gold, oil and global equity by means of spillovers and volatility transmission. Relying on the recently introduced ETFs, this study is the first to analyse return spillovers derived from an E-GARCH model and to take into account frequency dynamics to understand changes in connectedness across periods of time. Results uncover numerous channels of return transmission across the selected ETF markets over the last 10 years...

  11. Getting the Most out of Macroeconomic Information for Predicting Stock Returns and Volatility

    NARCIS (Netherlands)

    C. Cakmakli (Cem); D.J.C. van Dijk (Dick)

    2010-01-01

    textabstractThis paper documents that factors extracted from a large set of macroeconomic variables bear useful information for predicting monthly US excess stock returns and volatility over the period 1980-2005. Factor-augmented predictive regression models improve upon both benchmark models that

  12. Getting the most out of macroeconomic information for predicting stock returns and volatility

    NARCIS (Netherlands)

    Cakmakli, C.; van Dijk, D.

    2011-01-01

    This paper documents that factors extracted from a large set of macroeconomic variables bear useful information for predicting monthly US excess stock returns and volatility over the period 1980-2005. Factor-augmented predictive regression models improve upon both benchmark models that only include

  13. Impact of nuclear data uncertainty on safety calculations for spent nuclear fuel geological disposal

    Directory of Open Access Journals (Sweden)

    Herrero J.J.

    2017-01-01

    Full Text Available In the design of a spent nuclear fuel disposal system, one necessary condition is to show that the configuration remains subcritical at time of emplacement but also during long periods covering up to 1,000,000 years. In the context of criticality safety applying burn-up credit, k-eff eigenvalue calculations are affected by nuclear data uncertainty mainly in the burnup calculations simulating reactor operation and in the criticality calculation for the disposal canister loaded with the spent fuel assemblies. The impact of nuclear data uncertainty should be included in the k-eff value estimation to enforce safety. Estimations of the uncertainty in the discharge compositions from the CASMO5 burn-up calculation phase are employed in the final MCNP6 criticality computations for the intact canister configuration; in between, SERPENT2 is employed to get the spent fuel composition along the decay periods. In this paper, nuclear data uncertainty was propagated by Monte Carlo sampling in the burn-up, decay and criticality calculation phases and representative values for fuel operated in a Swiss PWR plant will be presented as an estimation of its impact.

  14. Moving Beyond 2% Uncertainty: A New Framework for Quantifying Lidar Uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    Newman, Jennifer F.; Clifton, Andrew

    2017-03-08

    Remote sensing of wind using lidar is revolutionizing wind energy. However, current generations of wind lidar are ascribed a climatic value of uncertainty, which is based on a poor description of lidar sensitivity to external conditions. In this presentation, we show how it is important to consider the complete lidar measurement process to define the measurement uncertainty, which in turn offers the ability to define a much more granular and dynamic measurement uncertainty. This approach is a progression from the 'white box' lidar uncertainty method.

  15. 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

  16. 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...

  17. MOV reliability evaluation and periodic verification scheduling

    Energy Technology Data Exchange (ETDEWEB)

    Bunte, B.D.

    1996-12-01

    The purpose of this paper is to establish a periodic verification testing schedule based on the expected long term reliability of gate or globe motor operated valves (MOVs). The methodology in this position paper determines the nominal (best estimate) design margin for any MOV based on the best available information pertaining to the MOVs design requirements, design parameters, existing hardware design, and present setup. The uncertainty in this margin is then determined using statistical means. By comparing the nominal margin to the uncertainty, the reliability of the MOV is estimated. The methodology is appropriate for evaluating the reliability of MOVs in the GL 89-10 program. It may be used following periodic testing to evaluate and trend MOV performance and reliability. It may also be used to evaluate the impact of proposed modifications and maintenance activities such as packing adjustments. In addition, it may be used to assess the impact of new information of a generic nature which impacts safety related MOVs.

  18. MOV reliability evaluation and periodic verification scheduling

    International Nuclear Information System (INIS)

    Bunte, B.D.

    1996-01-01

    The purpose of this paper is to establish a periodic verification testing schedule based on the expected long term reliability of gate or globe motor operated valves (MOVs). The methodology in this position paper determines the nominal (best estimate) design margin for any MOV based on the best available information pertaining to the MOVs design requirements, design parameters, existing hardware design, and present setup. The uncertainty in this margin is then determined using statistical means. By comparing the nominal margin to the uncertainty, the reliability of the MOV is estimated. The methodology is appropriate for evaluating the reliability of MOVs in the GL 89-10 program. It may be used following periodic testing to evaluate and trend MOV performance and reliability. It may also be used to evaluate the impact of proposed modifications and maintenance activities such as packing adjustments. In addition, it may be used to assess the impact of new information of a generic nature which impacts safety related MOVs

  19. Detecting The Expected Rate of Return Volatility of Financing Instruments of Indonesian Islamic Banking through GARCH Modeling (Generalized Autoregressive Conditional Heteroscedasticity

    Directory of Open Access Journals (Sweden)

    Nurul Huda

    2015-04-01

    Full Text Available Objective - Islamic banks are banks which its activities, both fund raising and funds distribution are on the basis of Islamic principles, namely buying and selling and profit sharing. Islamic banking is aimed at supporting the implementation of national development in order to improve justice, togetherness, and equitable distribution of welfare. In pursuit of supporting the implementation of national development, Islamic banking often faced stability problems of financing instruments being operated. In this case, it is measured by the gap between the actual rate of return and the expected rate of return. The individual actual RoR of this instrument will generate an expected rate of return. This raises the gap or difference between the actual rate of return and the expected rate of return of individual instruments, which in this case is called the abnormal rate of return. The stability of abnormal rate of return of individual instruments is certainly influenced by the stability of the expected rate of return. Expected rate of return has a volatility or fluctuation levels for each financing instrument. It is also a key element or material basis for the establishment of a variance of individual instruments. Variance in this case indicates the level of uncertainty of the rate of return. Individual variance is the origin of the instrument base for variance in the portfolio finance that further a portfolio analysis. So, this paper is going to analyze the level of expected RoR volatility as an initial step to see and predict the stability of the fluctuations in the rate of return of Indonesian Islamic financing instruments.Methods – Probability of Occurence, Expected Rate of Return (RoR and GARCH (Generalized Autoregressive Conditional Heteroscedasticity.Results - The expected RoR volatility of the murabaha and istishna financing instruments tend to be more volatile than expected RoR volatility of musharaka and qardh financing instruments

  20. Estimating Stocks Return with Decomposition of the Book-to-Market Ratio: Evidences from Bovespa

    Directory of Open Access Journals (Sweden)

    Juliano Ribeiro de Almeida

    2010-12-01

    Full Text Available The book-to-market (BM ratio differs across stocks because to differences in expected cashflows and expected returns. The central hypothesis is that the evolution of BM, in terms of past changes in price and book equity, contains information about future cashflows that can be used to improve estimates of expected returns. This article used a database of Economática to extract a sample of non-financial companies shares listed on BOVESPA and test this hypothesis. The estimated regressions were performed monthly during the period July 1996 to June 2008. Both for large and mid caps as for small caps, the results do not favor this hypothesis and show that only the most recent BM is important to predict the assets returns. Furthermore, stock issues and repurchases are also related to future cashflows and it is expected to improve estimates of expected returns. However, the results provide no evidence favoring that.

  1. Development of Property Models with Uncertainty Estimate for Process Design under Uncertainty

    DEFF Research Database (Denmark)

    Hukkerikar, Amol; Sarup, Bent; Abildskov, Jens

    more reliable predictions with a new and improved set of model parameters for GC (group contribution) based and CI (atom connectivity index) based models and to quantify the uncertainties in the estimated property values from a process design point-of-view. This includes: (i) parameter estimation using....... The comparison of model prediction uncertainties with reported range of measurement uncertainties is presented for the properties with related available data. The application of the developed methodology to quantify the effect of these uncertainties on the design of different unit operations (distillation column......, the developed methodology can be used to quantify the sensitivity of process design to uncertainties in property estimates; obtain rationally the risk/safety factors in process design; and identify additional experimentation needs in order to reduce most critical uncertainties....

  2. Institutional Venture Capital for the Space Industry: Providing Risk Capital for Space Companies that Provide Investor Returns

    Science.gov (United States)

    Moore, Roscoe M., III

    2002-01-01

    provided by an institution. Those institutions tend to be Banks, Pension Funds, Insurance Funds, Corporations, and other incorporated entities that are obligated to earn a return on their invested capital. These institutions invest in a venture capital firm for the sole purpose of getting their money back with a healthy profit - within a set period of time. The venture capital firm is responsible for investing in and managing companies whose risk and return are higher than other less risky classes of investment. The venture capital firm's primary skill is its ability to manage the high risk of its venture investments while maintaining the high return potential of its venture investments. to businesses for the purpose of providing the above-mentioned Institutions a substantial return on their invested capital. Institutional Venture Capital for the Space Industry cannot be provided to projects or companies whose philosophy or intention is not to increase shareholder equity value within a set time period. efficiently when tied up in companies that intend to spend billions of dollars before the first dollar of revenue is generated. If 2 billion dollars of venture capital is invested in the equity of a Space Company for a minority equity position, then that Space Company must build that minority shareholder's equity value to a minimum investment return of 4 to 8 billion dollars. There are not many start-up companies that are able to reach public market equity valuations in the tens of billions of dollars within reasonable time horizons. Foundations, Manufacturers, and Strategic Investors can invest in projects that cannot realistically provide a substantial return on their equity to their investors within a reasonable period (5-7 years) of time. Venture Capitalists have to make money. Venture capitalists have made money on Satellite Television, Satellite Radio, Fixed Satellite Services, and other businesses. Venture capitalists have not made money on stand

  3. Dampak Modal Intelektual Terhadap Kinerja Bank Umum Nasional Periode 2010-2015

    Directory of Open Access Journals (Sweden)

    Endang Pitaloka

    2017-12-01

    Full Text Available Abstract. The purpose of this study is to find out the influence of intellectual capital on Return on Asset of the National Commercial Bank 2010-2015 period. The intellectual capital variable as independent variable consists of Human Capital / Human Capital (HCE, Structured Capital (SCE, Capital Employed Capital (CEE.,and the dependent variable is Return on Assets (ROA. This study used secondary data sourced from the financial statements. The samples of this study are banks with assets of more than Rp. 50 trillion, include state-owned enterprise bank and private bank. Data analysis technique used in this research is pooled regression analysis. The results showed that both Human Capital (HCE and Capital Employed (CEE have significant influence and positive impact on Return on Asset (ROA at α = 5%. Although Structured Capital (SCE has no significant influence on Return on Asset (ROA, but SCE has positive impact on Return on Assets (ROA.   Keywords: Intellectual Capital; HCE; SCE; CEE; ROA.   Abstrak. Penelitian ini bertujuan untuk mengetahui pengaruh modal intelektual terhadap kinerja Bank Umum Nasional periode 2010-2015. Variabel modal intelektual sebagai variabel bebas terdiri dari: Modal Manusia / Human Capital (HCE, Modal Struktural / Structured Capital (SCE, Modal Kerja Capital Employed (CEE. Sedangkan variabel kinerja perusahaan sebagai variabel terikat adalah Return on Asset (ROA. Jenis data yang digunakan dalam penelitian ini adalah data sekunder yang bersumber dari laporan keuangan bank-bank yang diteliti. Adapun bank yang diteliti adalah bank umum milik pemerintah dan bank devisa swasta dengan aset lebih dari Rp. 50 triliun. Teknik analisis data yang digunakan dalam penelitian ini adalah analisis pooled regression analysis. Hasil penelitian menunjukkan bahwa Human Capital (HCE dan Capital Employed (CEE berdampak positif dan berpengaruh terhadap Return on Asset secara signifikan pada α = 5%. Variabel Structured Capital (SCE berdampak

  4. Prospective impact of illness uncertainty on outcomes in chronic lung disease.

    Science.gov (United States)

    Hoth, Karin F; Wamboldt, Frederick S; Strand, Matthew; Ford, Dee W; Sandhaus, Robert A; Strange, Charlie; Bekelman, David B; Holm, Kristen E

    2013-11-01

    To determine which aspect of illness uncertainty (i.e., ambiguity or complexity) has a stronger association with psychological and clinical outcomes over a 2-year period among individuals with a genetic subtype of chronic obstructive pulmonary disease (COPD). Ambiguity reflects uncertainty about physical cues and symptoms, and complexity reflects uncertainty about treatment and the medical system. Four-hundred and 7 individuals with alpha-1 antitrypsin deficiency-associated COPD completed questionnaires at baseline, 1- and 2-year follow-up. Uncertainty was measured using the Mishel Uncertainty in Illness Scale. Outcomes were measured using the Hospital Anxiety and Depression Scale, St. George's Respiratory Questionnaire, and MMRC Dyspnea Scale. Ambiguity and complexity were examined as predictors of depressive symptoms, anxiety, quality of life, and breathlessness using linear mixed models adjusting for demographic and health characteristics. Ambiguity was associated with more depressive symptoms (b = 0.09, SE = 0.02, p life (b = 0.57, SE = 0.10, p life, and breathlessness. Thus, ambiguity should be targeted in psychosocial interventions. Time since diagnosis did not affect the association between ambiguity and outcomes, suggesting that the impact of ambiguity is equally strong throughout the course of COPD.

  5. An Exact Soultion for the Investment and Market Value of a Firm Facing Uncertainty, Adjustment Costs, and Irreversibility

    OpenAIRE

    Andrew B. Abel; Janice C. Eberly

    1993-01-01

    This paper derives closed-form solutions for the investment and market value, under uncertainty, of competitive firms with constant returns to scale production and convex costs of adjustment. Solutions are derived for the case of irreversible investment as well as for reversible investment. Optimal investment is a non-decreasing function of q, the shadow value of capital. The conditions of optimality imply that q cannot contain a bubble; thus, optimal investment depends only on fundamentals. ...

  6. Quantifying uncertainty on sediment loads using bootstrap confidence intervals

    Science.gov (United States)

    Slaets, Johanna I. F.; Piepho, Hans-Peter; Schmitter, Petra; Hilger, Thomas; Cadisch, Georg

    2017-01-01

    Load estimates are more informative than constituent concentrations alone, as they allow quantification of on- and off-site impacts of environmental processes concerning pollutants, nutrients and sediment, such as soil fertility loss, reservoir sedimentation and irrigation channel siltation. While statistical models used to predict constituent concentrations have been developed considerably over the last few years, measures of uncertainty on constituent loads are rarely reported. Loads are the product of two predictions, constituent concentration and discharge, integrated over a time period, which does not make it straightforward to produce a standard error or a confidence interval. In this paper, a linear mixed model is used to estimate sediment concentrations. A bootstrap method is then developed that accounts for the uncertainty in the concentration and discharge predictions, allowing temporal correlation in the constituent data, and can be used when data transformations are required. The method was tested for a small watershed in Northwest Vietnam for the period 2010-2011. The results showed that confidence intervals were asymmetric, with the highest uncertainty in the upper limit, and that a load of 6262 Mg year-1 had a 95 % confidence interval of (4331, 12 267) in 2010 and a load of 5543 Mg an interval of (3593, 8975) in 2011. Additionally, the approach demonstrated that direct estimates from the data were biased downwards compared to bootstrap median estimates. These results imply that constituent loads predicted from regression-type water quality models could frequently be underestimating sediment yields and their environmental impact.

  7. The Relationship between Market Sentiment Index and Stock Rates of Return: a Panel Data Analysis

    Directory of Open Access Journals (Sweden)

    Claudia Emiko Yoshinaga

    2012-04-01

    Full Text Available This article analyzes the relationship between market sentiment and future stock rates of return. We used amethodology based on principal component analysis to create a sentiment index for the Brazilian market withdata from 1999 to 2008. The sample consisted of companies listed on BM&FBOVESPA which were groupedinto quintiles, each representing a portfolio, according to the magnitude of the following characteristics: marketvalue, total annualized risk and listing time on BM&FBOVESPA. Next, we calculated the average return of eachportfolio for every quarter. The data for the first and last quintiles were analyzed via two-factor ANOVA, usingsentiment index of the previous period (positive or negative as the main factor and each characteristic ascontrolling factors. Finally, the sentiment index was included in a panel data pricing model. The results indicatea significant and negative relationship between the market sentiment index and the future rates of return. Thesefindings suggest the existence of a reversion pattern in stock returns, meaning that after a positive sentimentperiod, the impact on subsequent stock returns is negative, and vice-versa.

  8. Long-range dependence in returns and volatility of global gold market amid financial crises

    Science.gov (United States)

    Omane-Adjepong, Maurice; Boako, Gideon

    2017-04-01

    Using sampled historical daily gold market data from 07-03-1985 to 06-01-2015, and building on a related work by Bentes (2016), this paper examines the presence of long-range dependence (LRD) in the world's gold market returns and volatility, accounting for structural breaks. The sampled gold market data was divided into subsamples based on four global crises: the September 1992 collapse of the European Exchange Rate Mechanism (ERM), the Asian financial crisis of mid-1997, the Subprime meltdown of 2007, and the recent European sovereign debt crisis, which hit the world's market with varying effects. LRD test was carried-out on the full-sample and subsample periods using three semiparametric methods-before and after adjusting for structural breaks. The results show insignificant evidence of LRD in gold returns. However, very diminutive evidence is found for periods characterized by financial/economic shocks, with no significant detections for post-shock periods. Collectively, this is indicative that the gold market is less speculative, and hence could be somehow less risky for hedging and portfolio diversification.

  9. 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

  10. An Empirical Research on Returns to Education of Disabled People during the Process of Modernization

    Directory of Open Access Journals (Sweden)

    Juan Liao

    2014-04-01

    Full Text Available Education is one of the most important ways to form human capital. Individual can get profit from investment in human capital. Although education situation of the disabled is getting better slowly during the process of modernization, the study of return to education of disabled has been largely ignored for many years. Furthermore, there are still a number of challenges need to pay more attention. This paper based on CHNS data in the economic transition period using Mincer Equation to study the returns to education in the disabled people in China. The results show that the education level has significant positive relationship with the rate of return to education; Return to education of the disabled is lower than non-disabled and male higher than female. The paper suggested more special education supply are required, female disabled people should be pay more attention especially on their education.

  11. Quantification of Wave Model Uncertainties Used for Probabilistic Reliability Assessments of Wave Energy Converters

    DEFF Research Database (Denmark)

    Ambühl, Simon; Kofoed, Jens Peter; Sørensen, John Dalsgaard

    2015-01-01

    Wave models used for site assessments are subjected to model uncertainties, which need to be quantified when using wave model results for probabilistic reliability assessments. This paper focuses on determination of wave model uncertainties. Four different wave models are considered, and validation...... data are collected from published scientific research. The bias and the root-mean-square error, as well as the scatter index, are considered for the significant wave height as well as the mean zero-crossing wave period. Based on an illustrative generic example, this paper presents how the quantified...... uncertainties can be implemented in probabilistic reliability assessments....

  12. Determination of Wave Model Uncertainties used for Probabilistic Reliability Assessments of Wave Energy Devices

    DEFF Research Database (Denmark)

    Ambühl, Simon; Kofoed, Jens Peter; Sørensen, John Dalsgaard

    2014-01-01

    Wave models used for site assessments are subject to model uncertainties, which need to be quantified when using wave model results for probabilistic reliability assessments. This paper focuses on determination of wave model uncertainties. Considered are four different wave models and validation...... data is collected from published scientific research. The bias, the root-mean-square error as well as the scatter index are considered for the significant wave height as well as the mean zero-crossing wave period. Based on an illustrative generic example it is shown how the estimated uncertainties can...... be implemented in probabilistic reliability assessments....

  13. Optimization on replacement period of plant equipment

    International Nuclear Information System (INIS)

    Kasai, Masao; Asano, Hiromi

    2002-01-01

    Optimization of the replacement period of plant equipment is one of the main items to rationalize the activities on plant maintenance. There are several models to replace the equipment and the formulations for optimizing the replacement period are different among these models. In this study, we calculated the optimum replacement periods for some equipment parts based on the replacement models and found that the optimum solutions are not so largely differ from the replacement models as far as the replacement period is not so large. So we will be able to use the most usable model especially in the early phase of rationalization on plant maintenance, since there are large uncertainties in data for optimization. (author)

  14. 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...

  15. [Knowledge of Man Returns: Some Considerations on Spirituality and Resilience].

    Science.gov (United States)

    Kumakura, Nobuhiro

    2015-01-01

    Over the last decade,"spirituality" and "resilience" have jointly become a topic in psychiatry. The aim of this paper is to discuss the future of psychiatry suggested by this topic. It may be related to what Jaspers, K. called "Knowledge of Man (die Erkenntnis des Menschen)". Knowledge of man in psychiatry can be learned only through clinical experince: e. g., clinical observations and case studies. Modern academic psychiatry seems to be suffering a loss of knowledge of man, which returns periodically in clinical practice. Hence, I will call the re-discovery of the topic in psychiatry as "Return of Man". Since WW II, there have been three eras in which psychiatrists showed deep concern regarding knowledge of man. Firstly, psychopathology and psychotherapy widely developed, when the destructive impulses of mankind were revealed in the nuclear weapons of WW II. Secondly, in the 1970's, the reforms of psychiatric services and legal systems took place somewhat successfully, when social reforms were concerns of the younger generations. Lastly, over the last decade, the topic again returned as spirituality and resilience, when scientists seemed to be powerless in the aftermath of the West Japan Earthquake. Regarding the definition of health made by the WHO in 1946, I further discuss that "Return of Man" in psychiatry is the necessary dynamism between negative and positive health, or between disease control and health promotion. There is an underlying dynamism between "Knowledge of Man" and natural sciences, which is constantly changing. So long as any theory can exist only as a part of dynamism, the Return of Man may re-surface whenever clinical theories do not fit with clinical realities.

  16. Results from the Application of Uncertainty Methods in the CSNI Uncertainty Methods Study (UMS)

    International Nuclear Information System (INIS)

    Glaeser, H.

    2008-01-01

    Within licensing procedures there is the incentive to replace the conservative requirements for code application by a - best estimate - concept supplemented by an uncertainty analysis to account for predictive uncertainties of code results. Methods have been developed to quantify these uncertainties. The Uncertainty Methods Study (UMS) Group, following a mandate from CSNI, has compared five methods for calculating the uncertainty in the predictions of advanced -best estimate- thermal-hydraulic codes. Most of the methods identify and combine input uncertainties. The major differences between the predictions of the methods came from the choice of uncertain parameters and the quantification of the input uncertainties, i.e. the wideness of the uncertainty ranges. Therefore, suitable experimental and analytical information has to be selected to specify these uncertainty ranges or distributions. After the closure of the Uncertainty Method Study (UMS) and after the report was issued comparison calculations of experiment LSTF-SB-CL-18 were performed by University of Pisa using different versions of the RELAP 5 code. It turned out that the version used by two of the participants calculated a 170 K higher peak clad temperature compared with other versions using the same input deck. This may contribute to the differences of the upper limit of the uncertainty ranges.

  17. Information Seeking in Uncertainty Management Theory: Exposure to Information About Medical Uncertainty and Information-Processing Orientation as Predictors of Uncertainty Management Success.

    Science.gov (United States)

    Rains, Stephen A; Tukachinsky, Riva

    2015-01-01

    Uncertainty management theory outlines the processes through which individuals cope with health-related uncertainty. Information seeking has been frequently documented as an important uncertainty management strategy. The reported study investigates exposure to specific types of medical information during a search, and one's information-processing orientation as predictors of successful uncertainty management (i.e., a reduction in the discrepancy between the level of uncertainty one feels and the level one desires). A lab study was conducted in which participants were primed to feel more or less certain about skin cancer and then were allowed to search the World Wide Web for skin cancer information. Participants' search behavior was recorded and content analyzed. The results indicate that exposure to two health communication constructs that pervade medical forms of uncertainty (i.e., severity and susceptibility) and information-processing orientation predicted uncertainty management success.

  18. Multi-year assessment of soil-vegetation-atmosphere transfer (SVAT) modeling uncertainties over a Mediterranean agricultural site

    Science.gov (United States)

    Garrigues, S.; Olioso, A.; Calvet, J.-C.; Lafont, S.; Martin, E.; Chanzy, A.; Marloie, O.; Bertrand, N.; Desfonds, V.; Renard, D.

    2012-04-01

    Vegetation productivity and water balance of Mediterranean regions will be particularly affected by climate and land-use changes. In order to analyze and predict these changes through land surface models, a critical step is to quantify the uncertainties associated with these models (processes, parameters) and their implementation over a long period of time. Besides, uncertainties attached to the data used to force these models (atmospheric forcing, vegetation and soil characteristics, crop management practices...) which are generally available at coarse spatial resolution (>1-10 km) and for a limited number of plant functional types, need to be evaluated. This paper aims at assessing the uncertainties in water (evapotranspiration) and energy fluxes estimated from a Soil Vegetation Atmosphere Transfer (SVAT) model over a Mediterranean agricultural site. While similar past studies focused on particular crop types and limited period of time, the originality of this paper consists in implementing the SVAT model and assessing its uncertainties over a long period of time (10 years), encompassing several cycles of distinct crops (wheat, sorghum, sunflower, peas). The impacts on the SVAT simulations of the following sources of uncertainties are characterized: - Uncertainties in atmospheric forcing are assessed comparing simulations forced with local meteorological measurements and simulations forced with re-analysis atmospheric dataset (SAFRAN database). - Uncertainties in key surface characteristics (soil, vegetation, crop management practises) are tested comparing simulations feeded with standard values from global database (e.g. ECOCLIMAP) and simulations based on in situ or site-calibrated values. - Uncertainties dues to the implementation of the SVAT model over a long period of time are analyzed with regards to crop rotation. The SVAT model being analyzed in this paper is ISBA in its a-gs version which simulates the photosynthesis and its coupling with the stomata

  19. 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.

  20. Corporate governance and performance of Turkish banks in the pre- and post-crisis periods

    Directory of Open Access Journals (Sweden)

    F. Dilvin Taşkin

    2012-11-01

    Full Text Available This paper aims to analyze the relationship between corporate governance and bank performance. Return on asset (ROA, return on equity (ROE and net interest margin (NIM is considered as the measures of bank performance. Corporate governance is determined through the measures of internal governance mechanism which is measured by CEO duality and external governance mechanisms which are proxied by discipline exerted by shareholders, creditors and educated personnel and bank ownership. The analysis covers the period 1990-2000 and 2002-2011 which are the pre and post periods of the severe 2001 banking crisis. The results show that different governance characteristics are important in the pre and post crisis periods.

  1. Relationship between Gold and Oil Prices and Stock Market Returns

    Directory of Open Access Journals (Sweden)

    Muhammad Mansoor Baig

    2013-10-01

    Full Text Available This study objective to examine the relationship between gold prices, oil prices and KSE100 return. This study important for the investor whose want to invest in real assets and financial assets. This study helps investor to achieve the portfolio diversification. This study uses the monthly data of gold prices, KSE100, and oil prices for the period of 2000 to 2010 (monthly. This study applied Descriptive statistics, Augmented Dickey Fuller test Phillip Perron test, Johansen and Jelseluis Co-integration test, Variance Decomposition test to find relationship. This study concludes that Gold prices growth, Oil prices growth and KSE100 return have no significant relationship in the long run. This study provides information to the investors who want to get the benefit of diversification by investing in Gold, Oil and stock market. In the current era Gold prices and oil prices are fluctuating day by day and investors think that stock returns may or may not affected by these fluctuations. This study is unique because it focuses on current issues and takes the current data in this research to help the investment institutions or portfolio managers.

  2. Estimating investor preferences towards portfolio return distribution in investment funds

    Directory of Open Access Journals (Sweden)

    Margareta Gardijan

    2015-03-01

    Full Text Available Recent research in the field of investor preference has emphasised the need to go beyond just simply analyzing the first two moments of a portfolio return distribution used in a MV (mean-variance paradigm. The suggestion is to observe an investor's utility function as an nth order Taylor approximation. In such terms, the assumption is that investors prefer greater values of odd and smaller values of even moments. In order to investigate the preferences of Croatian investment funds, an analysis of the moments of their return distribution is conducted. The sample contains data on monthly returns of 30 investment funds in Croatia for the period from January 1999 to May 2014. Using the theoretical utility functions (DARA, CARA, CRRA, we compare changes in their preferences when higher moments are included. Moreover, we investigate an extension of the CAPM model in order to find out whether including higher moments can explain better the relationship between the awards and risk premium, and whether we can apply these findings to estimate preferences of Croatian institutional investors. The results indicate that Croatian institutional investors do not seek compensation for bearing greater market risk.

  3. 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.

  4. Arthroscopic Shoulder Surgery in Female Professional Tennis Players: Ability and Timing to Return to Play.

    Science.gov (United States)

    Young, Simon W; Dakic, Jodie; Stroia, Kathleen; Nguyen, Michael L; Safran, Marc R

    2017-07-01

    To assess the outcome and time to return to previous level of competitive play after shoulder surgery in professional tennis players. Retrospective case series. Tertiary academic centre. The records of all female tennis players on the Women's Tennis Association (WTA) professional circuit between January 2008 and June 2010 were reviewed to identify players who underwent shoulder surgery on their dominant (serving) shoulder. Primary outcomes were the ability and time to return to professional play and if they were able to return to their previous level of function as determined by singles ranking. Preoperative and postoperative singles rankings were used to determine rate and completeness of return to preoperative function. During the study period, 8 professional women tennis players from the WTA tour underwent shoulder surgery on their dominant arm. Indications included rotator cuff debridement or repair, labral reconstruction for instability or superior labral anterior posterior lesion, and neurolysis of the suprascapular nerve. Seven players (88%) returned to professional play. The mean time to return to play was 7 months after surgery. However, only 25% (2 of 8) players achieved their preinjury singles rank or better by 18 months postoperatively. In total, 4 players returned to their preinjury singles ranking, with their peak singles ranking being attained at a mean of 2.4 years postoperatively. In professional female tennis players, a high return to play rate after arthroscopic shoulder surgery is associated with a prolonged and often incomplete return to previous level of performance. Thus, counseling the patient to this fact is important to manage expectations. Level IV-Case Series.

  5. The Asymmetric Impulse of the Sunshine Effect on Stock Returns and Volatilities

    OpenAIRE

    Yuan-Ming Lee; Kuan-Min Wang

    2010-01-01

    This study constructs a variety of GARCH models with the consideration of the generalized error distribution to analyze the relationship between the cloud cover and stock returns in Taiwan in the whole sample period (1986 to 2007) and in the two sub-sample periods (1986 to 1996 and 1997 to 2007). The data include Taiwan Stock Exchange Capitalization Weighted Stock Index and the U.S. Dow Jones Industrial Average index to proxy the impact of U.S. stock market on Taiwan’s stock market performanc...

  6. Aleatoric and epistemic uncertainties in sampling based nuclear data uncertainty and sensitivity analyses

    International Nuclear Information System (INIS)

    Zwermann, W.; Krzykacz-Hausmann, B.; Gallner, L.; Klein, M.; Pautz, A.; Velkov, K.

    2012-01-01

    Sampling based uncertainty and sensitivity analyses due to epistemic input uncertainties, i.e. to an incomplete knowledge of uncertain input parameters, can be performed with arbitrary application programs to solve the physical problem under consideration. For the description of steady-state particle transport, direct simulations of the microscopic processes with Monte Carlo codes are often used. This introduces an additional source of uncertainty, the aleatoric sampling uncertainty, which is due to the randomness of the simulation process performed by sampling, and which adds to the total combined output sampling uncertainty. So far, this aleatoric part of uncertainty is minimized by running a sufficiently large number of Monte Carlo histories for each sample calculation, thus making its impact negligible as compared to the impact from sampling the epistemic uncertainties. Obviously, this process may cause high computational costs. The present paper shows that in many applications reliable epistemic uncertainty results can also be obtained with substantially lower computational effort by performing and analyzing two appropriately generated series of samples with much smaller number of Monte Carlo histories each. The method is applied along with the nuclear data uncertainty and sensitivity code package XSUSA in combination with the Monte Carlo transport code KENO-Va to various critical assemblies and a full scale reactor calculation. It is shown that the proposed method yields output uncertainties and sensitivities equivalent to the traditional approach, with a high reduction of computing time by factors of the magnitude of 100. (authors)

  7. Uncertainty, probability and information-gaps

    International Nuclear Information System (INIS)

    Ben-Haim, Yakov

    2004-01-01

    This paper discusses two main ideas. First, we focus on info-gap uncertainty, as distinct from probability. Info-gap theory is especially suited for modelling and managing uncertainty in system models: we invest all our knowledge in formulating the best possible model; this leaves the modeller with very faulty and fragmentary information about the variation of reality around that optimal model. Second, we examine the interdependence between uncertainty modelling and decision-making. Good uncertainty modelling requires contact with the end-use, namely, with the decision-making application of the uncertainty model. The most important avenue of uncertainty-propagation is from initial data- and model-uncertainties into uncertainty in the decision-domain. Two questions arise. Is the decision robust to the initial uncertainties? Is the decision prone to opportune windfall success? We apply info-gap robustness and opportunity functions to the analysis of representation and propagation of uncertainty in several of the Sandia Challenge Problems

  8. Crude oil price shocks and stock returns. Evidence from Turkish stock market under global liquidity conditions

    Energy Technology Data Exchange (ETDEWEB)

    Berk, Istemi [Koeln Univ. (Germany). Energiewirtschaftliches Inst.; Aydogan, Berna [Izmir Univ. of Economics (Turkey). Dept. of International Trade and Finance

    2012-09-15

    The purpose of this study is to investigate the impacts of crude oil price variations on the Turkish stock market returns. We have employed vector autoregression (V AR) model using daily observations of Brent crude oil prices and Istanbul Stock Exchange National Index (ISE- 1 00) returns for the period between January 2, 1990 and November 1, 2011. We have also tested the relationship between oil prices and stock market returns under global liquidity conditions by incorporating a liquidity proxy variable, Chicago Board of Exchange's (CBOE) S and P 500 market volatility index (VIX), into the model. Variance decomposition test results suggest little empirical evidence that crude oil price shocks have been rationally evaluated in the Turkish stock market. Rather, it was global liquidity conditions that were found to account for the greatest amount of variation in stock market returns.

  9. Fundamental uncertainty limit of optical flow velocimetry according to Heisenberg's uncertainty principle.

    Science.gov (United States)

    Fischer, Andreas

    2016-11-01

    Optical flow velocity measurements are important for understanding the complex behavior of flows. Although a huge variety of methods exist, they are either based on a Doppler or a time-of-flight measurement principle. Doppler velocimetry evaluates the velocity-dependent frequency shift of light scattered at a moving particle, whereas time-of-flight velocimetry evaluates the traveled distance of a scattering particle per time interval. Regarding the aim of achieving a minimal measurement uncertainty, it is unclear if one principle allows to achieve lower uncertainties or if both principles can achieve equal uncertainties. For this reason, the natural, fundamental uncertainty limit according to Heisenberg's uncertainty principle is derived for Doppler and time-of-flight measurement principles, respectively. The obtained limits of the velocity uncertainty are qualitatively identical showing, e.g., a direct proportionality for the absolute value of the velocity to the power of 32 and an indirect proportionality to the square root of the scattered light power. Hence, both measurement principles have identical potentials regarding the fundamental uncertainty limit due to the quantum mechanical behavior of photons. This fundamental limit can be attained (at least asymptotically) in reality either with Doppler or time-of-flight methods, because the respective Cramér-Rao bounds for dominating photon shot noise, which is modeled as white Poissonian noise, are identical with the conclusions from Heisenberg's uncertainty principle.

  10. A Follow-up Study of Returning Students--A Concentration on Women.

    Science.gov (United States)

    Plotsky, Frances; Ohm, Susan

    The office of Services for Returning Students (SRS) at the University of Texas (U.T.) at Austin conducted a follow-up study of men and women students who had visited the office from February 1969 to the end of 1971. The study ascertained the average interval between periods of formal education, the fulfillment of educational goals, and the use of…

  11. Clinical providers' experiences with returning results from genomic sequencing: an interview study.

    Science.gov (United States)

    Wynn, Julia; Lewis, Katie; Amendola, Laura M; Bernhardt, Barbara A; Biswas, Sawona; Joshi, Manasi; McMullen, Carmit; Scollon, Sarah

    2018-05-08

    Current medical practice includes the application of genomic sequencing (GS) in clinical and research settings. Despite expanded use of this technology, the process of disclosure of genomic results to patients and research participants has not been thoroughly examined and there are no established best practices. We conducted semi-structured interviews with 21 genetic and non-genetic clinicians returning results of GS as part of the NIH funded Clinical Sequencing Exploratory Research (CSER) Consortium projects. Interviews focused on the logistics of sessions, participant/patient reactions and factors influencing them, how the sessions changed with experience, and resources and training recommended to return genomic results. The length of preparation and disclosure sessions varied depending on the type and number of results and their implications. Internal and external databases, online resources and result review meetings were used to prepare. Respondents reported that participants' reactions were variable and ranged from enthusiasm and relief to confusion and disappointment. Factors influencing reactions were types of results, expectations and health status. A recurrent challenge was managing inflated expectations about GS. Other challenges included returning multiple, unanticipated and/or uncertain results and navigating a rare diagnosis. Methods to address these challenges included traditional genetic counseling techniques and modifying practice over time in order to provide anticipatory guidance and modulate expectations. Respondents made recommendations to improve access to genomic resources and genetic referrals to prepare future providers as the uptake of GS increases in both genetic and non-genetic settings. These findings indicate that returning genomic results is similar to return of results in traditional genetic testing but is magnified by the additional complexity and potential uncertainty of the results. Managing patient expectations, initially

  12. 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 ...

  13. 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 ...

  14. PERSISTENCE IN PERFORMANCE FOR MUTUAL FUNDS IN PERIODS OF CRISIS

    Directory of Open Access Journals (Sweden)

    Theodoros KARGIDIS

    2012-09-01

    Full Text Available The study investigates the persistence in performance for a sample of South European funds, domiciled in Portugal, Italy, Greece and Spain. Employing the Sharpe ratio, risk adjusted performance is measured in an attempt to judge the influence of the 2008 crisis and the current debt crisis on funds’ inclination to persist in their previous returns record. Examination period extends from January 2004 to December 2010 incorporating stages of relative stability in the stock and bond markets while also capturing the early stages of the eurozone crisis. We categorize funds as winners and losers in consecutive 6-monthly periods, thus being able to judge persistence in the short run, while our results suggest that the identification of winners and losers could enable us to investigate the possibility to gain investment advantages through this finding. Overall results suggest evidence of persistent results, whether positive or negative, both during the 2008 crisis and the current debt crisis, leading us to deduce that factors leading to performance persistence are not affected by market changes, since medium to long term persistence bypasses any temporary market mischief. This finding could be of use for fund managers aiming at establishing viable investment strategies, at their epicenter being the exploitation of such clues, suggesting persistence in returns. A fund of funds manager employing funds both in equities and fixed income could potentially choose to invest exclusively or more heavily in the winners of previous periods and avoid accordingly poor performers, thus achieving higher returns on average. For this purpose simple investment strategies are employed where we test the outcome of an investment strategy that would invest on fixed income securities by choosing those funds that were winners in the distribution of returns in the previous 6-monthly period, while disinvesting from poor performers and funds switching sides in performance

  15. Longer Nature-Based Rehabilitation May Contribute to a Faster Return to Work in Patients with Reactions to Severe Stress and/or Depression.

    Science.gov (United States)

    Grahn, Patrik; Pálsdóttir, Anna María; Ottosson, Johan; Jonsdottir, Ingibjörg H

    2017-10-27

    The global burden of depression and stress-related mental disorders is substantial, and constitutes a major need for effective rehabilitation. Can nature-based rehabilitation help people return to work? To study if the length of a nature-based rehabilitation program affects the outcome with regard to return to work one year after the onset of the program, in a group of patients with long-term reactions to severe stress and/or depression. A prospective, quasi-experimental study comparing results from 8-, 12-, and 24-week periods of rehabilitation. The rehabilitation of 106 participants was carried out by a multimodal rehabilitation team in a specially designed rehabilitation garden. Return to work data were collected before the intervention and one year after the start of rehabilitation. In addition, data were collected regarding self-assessed occupational competence, personal control, and sense of coherence. As many as 68% of the participants returned to work or participated in job training or work-oriented measures, full- or part-time, after one year. Participants with a longer period of rehabilitation reported better results on occupational competence, and were more likely to participate in paid work, full-time or part-time, one year after rehabilitation. Study outcomes indicate that a longer rehabilitation period in a rehabilitation garden increases the possibility of a return to paid work.

  16. Longer Nature-Based Rehabilitation May Contribute to a Faster Return to Work in Patients with Reactions to Severe Stress and/or Depression

    Science.gov (United States)

    Grahn, Patrik; Pálsdóttir, Anna María; Ottosson, Johan; Jonsdottir, Ingibjörg H.

    2017-01-01

    The global burden of depression and stress-related mental disorders is substantial, and constitutes a major need for effective rehabilitation. Can nature-based rehabilitation help people return to work? Objective: To study if the length of a nature-based rehabilitation program affects the outcome with regard to return to work one year after the onset of the program, in a group of patients with long-term reactions to severe stress and/or depression. Methods: A prospective, quasi-experimental study comparing results from 8-, 12-, and 24-week periods of rehabilitation. The rehabilitation of 106 participants was carried out by a multimodal rehabilitation team in a specially designed rehabilitation garden. Return to work data were collected before the intervention and one year after the start of rehabilitation. In addition, data were collected regarding self-assessed occupational competence, personal control, and sense of coherence. As many as 68% of the participants returned to work or participated in job training or work-oriented measures, full- or part-time, after one year. Participants with a longer period of rehabilitation reported better results on occupational competence, and were more likely to participate in paid work, full-time or part-time, one year after rehabilitation. Study outcomes indicate that a longer rehabilitation period in a rehabilitation garden increases the possibility of a return to paid work. PMID:29076997

  17. Longer Nature-Based Rehabilitation May Contribute to a Faster Return to Work in Patients with Reactions to Severe Stress and/or Depression

    Directory of Open Access Journals (Sweden)

    Patrik Grahn

    2017-10-01

    Full Text Available The global burden of depression and stress-related mental disorders is substantial, and constitutes a major need for effective rehabilitation. Can nature-based rehabilitation help people return to work? Objective: To study if the length of a nature-based rehabilitation program affects the outcome with regard to return to work one year after the onset of the program, in a group of patients with long-term reactions to severe stress and/or depression. Methods: A prospective, quasi-experimental study comparing results from 8-, 12-, and 24-week periods of rehabilitation. The rehabilitation of 106 participants was carried out by a multimodal rehabilitation team in a specially designed rehabilitation garden. Return to work data were collected before the intervention and one year after the start of rehabilitation. In addition, data were collected regarding self-assessed occupational competence, personal control, and sense of coherence. As many as 68% of the participants returned to work or participated in job training or work-oriented measures, full- or part-time, after one year. Participants with a longer period of rehabilitation reported better results on occupational competence, and were more likely to participate in paid work, full-time or part-time, one year after rehabilitation. Study outcomes indicate that a longer rehabilitation period in a rehabilitation garden increases the possibility of a return to paid work.

  18. QR-GARCH-M Model for Risk-Return Tradeoff in U.S. Stock Returns and Business Cycles

    OpenAIRE

    Nyberg, Henri

    2010-01-01

    In the empirical finance literature findings on the risk return tradeoff in excess stock market returns are ambiguous. In this study, we develop a new QR-GARCH-M model combining a probit model for a binary business cycle indicator and a regime switching GARCH-in-mean model for excess stock market return with the business cycle indicator defining the regime. Estimation results show that there is statistically significant variation in the U.S. excess stock returns over the business cycle. Howev...

  19. Controlling quantum memory-assisted entropic uncertainty in non-Markovian environments

    Science.gov (United States)

    Zhang, Yanliang; Fang, Maofa; Kang, Guodong; Zhou, Qingping

    2018-03-01

    Quantum memory-assisted entropic uncertainty relation (QMA EUR) addresses that the lower bound of Maassen and Uffink's entropic uncertainty relation (without quantum memory) can be broken. In this paper, we investigated the dynamical features of QMA EUR in the Markovian and non-Markovian dissipative environments. It is found that dynamical process of QMA EUR is oscillation in non-Markovian environment, and the strong interaction is favorable for suppressing the amount of entropic uncertainty. Furthermore, we presented two schemes by means of prior weak measurement and posterior weak measurement reversal to control the amount of entropic uncertainty of Pauli observables in dissipative environments. The numerical results show that the prior weak measurement can effectively reduce the wave peak values of the QMA-EUA dynamic process in non-Markovian environment for long periods of time, but it is ineffectual on the wave minima of dynamic process. However, the posterior weak measurement reversal has an opposite effects on the dynamic process. Moreover, the success probability entirely depends on the quantum measurement strength. We hope that our proposal could be verified experimentally and might possibly have future applications in quantum information processing.

  20. A Variation on Uncertainty Principle and Logarithmic Uncertainty Principle for Continuous Quaternion Wavelet Transforms

    Directory of Open Access Journals (Sweden)

    Mawardi Bahri

    2017-01-01

    Full Text Available The continuous quaternion wavelet transform (CQWT is a generalization of the classical continuous wavelet transform within the context of quaternion algebra. First of all, we show that the directional quaternion Fourier transform (QFT uncertainty principle can be obtained using the component-wise QFT uncertainty principle. Based on this method, the directional QFT uncertainty principle using representation of polar coordinate form is easily derived. We derive a variation on uncertainty principle related to the QFT. We state that the CQWT of a quaternion function can be written in terms of the QFT and obtain a variation on uncertainty principle related to the CQWT. Finally, we apply the extended uncertainty principles and properties of the CQWT to establish logarithmic uncertainty principles related to generalized transform.

  1. Uncertainty Einstein, Heisenberg, Bohr, and the struggle for the soul of science

    CERN Document Server

    Lindley, David

    2007-01-01

    The uncertainty in this delightful book refers to Heisenberg's Uncertainty Principle, an idea first postulated in 1927 by physicist Werner Heisenberg in his attempt to make sense out of the developing field of quantum mechanics. As Lindley so well explains it, the concept of uncertainty shook the philosophical underpinnings of science. It was Heisenberg's work that, to a great extent, kept Einstein from accepting quantum mechanics as a full explanation for physical reality. Similarly, it was the Uncertainty Principle that demonstrated the limits of scientific investigation: if Heisenberg is correct there are some aspects of the physical universe that are to remain beyond the reach of scientists. As he has done expertly in books like Boltzmann's Atom, Lindley brings to life a critical period in the history of science, explaining complex issues to the general reader, presenting the major players in an engaging fashion, delving into the process of scientific discovery and discussing the interaction between scien...

  2. 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...

  3. Time trend analysis of return to work after stroke in Denmark 1996-2006

    DEFF Research Database (Denmark)

    Hannerz, Harald; Mortensen, Ole S; Poulsen, Otto M

    2012-01-01

    In the period 1997-2005, the Danish government initiated a series of legislative changes aimed at facilitating RTW (return to work) in the Danish population. In the present study, we investigated the odds of being gainfully occupied ca. two years after stroke as a function of onset calendar year,...

  4. 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)

  5. KOMPARASI CAPITAL ASSET PRICING MODEL VERSUS ARBITRAGE PRICING THEORY MODEL ATAS VOLATILITAS RETURN SAHAM

    Directory of Open Access Journals (Sweden)

    Mathius Tandiontong

    2017-03-01

    Full Text Available Investing in the stock market is one option for investors. Investment in ordinary shares was classified as longterminvestments to be able to provide added value and the risk for fixed income. This study focused on thedifference of APTM versus CAPM, and it also focused on the sensitivity of the APTM on the stock returns. Thisstudy was based on the assumption that: there were differences in sectoral stock return volatility, volatility ofmarket risk factors, and macroeconomic risks affecting sectoral differences in the sensitivity of stock returns;there were differences in the results of testing the validity, robustness unconditional CAPM and APTMmultifactorial; and time-varying volatility referring to the phenomena of structural breaks and asymmetriceffect. The method of analysis used nested models with panel data. Data were analyzed by using secondary datafrom 2005-2012. The results of this study concluded that: there was no different sensitivity of stock returnsacross sectors, but there was different insensitivity between systematic risk factors, CAPM and APTM multifactorthat showed the inconsistency of the sectoral shares, but the proven model of unconditional CAPM wasvalid; the difference of factor risk premiums was as a result of the structural break, the financial crisis period of2008 within the period 2005-2012.

  6. Psychometric Properties of the Intolerance of Uncertainty Scale (IUS in a Lithuanian-speaking population

    Directory of Open Access Journals (Sweden)

    Augustinas Rotomskis

    2014-03-01

    Full Text Available Research suggests that intolerance of uncertainty may be important in understanding worry and may play a key role in the etiology and maintenance of worry. Intolerance of uncertainty is measured using the Intolerance of Uncertainty Scale (IUS, which has been shown to be reliable and valid in many studies. The aim of the present study was to develop a Lithuanian version of this instrument. 228 university students completed the scale. The Lithuanian version of the IUS was found to have good psychometric properties. The IUS showed high internal consistency and good test-retest reliability over a five-week period, and good convergent and divergent validity when assessed with measures of trait anxiety, situational anxiety, and depression. Factor analysis indicated that the IUS has a two-factor structure that represents the beliefs that “uncertainty about the future is unfair” and that “uncertainty has negative behavioral and self-referent implications”. In conclusion, it was found that the Lithuanian version of the IUS is a sound scale for assessing intolerance of uncertainty.

  7. The point of no return: A fundamental limit on the ability to control thought and action.

    Science.gov (United States)

    Logan, Gordon D

    2015-01-01

    Bartlett (1958. Thinking. New York: Basic Books) described the point of no return as a point of irrevocable commitment to action, which was preceded by a period of gradually increasing commitment. As such, the point of no return reflects a fundamental limit on the ability to control thought and action. I review the literature on the point of no return, taking three perspectives. First, I consider the point of no return from the perspective of the controlled act, as a locus in the architecture and anatomy of the underlying processes. I review experiments from the stop-signal paradigm that suggest that the point of no return is located late in the response system. Then I consider the point of no return from the perspective of the act of control that tries to change the controlled act before it becomes irrevocable. From this perspective, the point of no return is a point in time that provides enough "lead time" for the act of control to take effect. I review experiments that measure the response time to the stop signal as the lead time required for response inhibition in the stop-signal paradigm. Finally, I consider the point of no return in hierarchically controlled tasks, in which there may be many points of no return at different levels of the hierarchy. I review experiments on skilled typing that suggest different points of no return for the commands that determine what is typed and the countermands that inhibit typing, with increasing commitment to action the lower the level in the hierarchy. I end by considering the point of no return in perception and thought as well as action.

  8. 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.)

  9. Application of a Novel Dose-Uncertainty Model for Dose-Uncertainty Analysis in Prostate Intensity-Modulated Radiotherapy

    International Nuclear Information System (INIS)

    Jin Hosang; Palta, Jatinder R.; Kim, You-Hyun; Kim, Siyong

    2010-01-01

    Purpose: To analyze dose uncertainty using a previously published dose-uncertainty model, and to assess potential dosimetric risks existing in prostate intensity-modulated radiotherapy (IMRT). Methods and Materials: The dose-uncertainty model provides a three-dimensional (3D) dose-uncertainty distribution in a given confidence level. For 8 retrospectively selected patients, dose-uncertainty maps were constructed using the dose-uncertainty model at the 95% CL. In addition to uncertainties inherent to the radiation treatment planning system, four scenarios of spatial errors were considered: machine only (S1), S1 + intrafraction, S1 + interfraction, and S1 + both intrafraction and interfraction errors. To evaluate the potential risks of the IMRT plans, three dose-uncertainty-based plan evaluation tools were introduced: confidence-weighted dose-volume histogram, confidence-weighted dose distribution, and dose-uncertainty-volume histogram. Results: Dose uncertainty caused by interfraction setup error was more significant than that of intrafraction motion error. The maximum dose uncertainty (95% confidence) of the clinical target volume (CTV) was smaller than 5% of the prescribed dose in all but two cases (13.9% and 10.2%). The dose uncertainty for 95% of the CTV volume ranged from 1.3% to 2.9% of the prescribed dose. Conclusions: The dose uncertainty in prostate IMRT could be evaluated using the dose-uncertainty model. Prostate IMRT plans satisfying the same plan objectives could generate a significantly different dose uncertainty because a complex interplay of many uncertainty sources. The uncertainty-based plan evaluation contributes to generating reliable and error-resistant treatment plans.

  10. 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...

  11. Regional inversion of CO2 ecosystem fluxes from atmospheric measurements. Reliability of the uncertainty estimates

    Energy Technology Data Exchange (ETDEWEB)

    Broquet, G.; Chevallier, F.; Breon, F.M.; Yver, C.; Ciais, P.; Ramonet, M.; Schmidt, M. [Laboratoire des Sciences du Climat et de l' Environnement, CEA-CNRS-UVSQ, UMR8212, IPSL, Gif-sur-Yvette (France); Alemanno, M. [Servizio Meteorologico dell' Aeronautica Militare Italiana, Centro Aeronautica Militare di Montagna, Monte Cimone/Sestola (Italy); Apadula, F. [Research on Energy Systems, RSE, Environment and Sustainable Development Department, Milano (Italy); Hammer, S. [Universitaet Heidelberg, Institut fuer Umweltphysik, Heidelberg (Germany); Haszpra, L. [Hungarian Meteorological Service, Budapest (Hungary); Meinhardt, F. [Federal Environmental Agency, Kirchzarten (Germany); Necki, J. [AGH University of Science and Technology, Krakow (Poland); Piacentino, S. [ENEA, Laboratory for Earth Observations and Analyses, Palermo (Italy); Thompson, R.L. [Max Planck Institute for Biogeochemistry, Jena (Germany); Vermeulen, A.T. [Energy research Centre of the Netherlands ECN, EEE-EA, Petten (Netherlands)

    2013-07-01

    The Bayesian framework of CO2 flux inversions permits estimates of the retrieved flux uncertainties. Here, the reliability of these theoretical estimates is studied through a comparison against the misfits between the inverted fluxes and independent measurements of the CO2 Net Ecosystem Exchange (NEE) made by the eddy covariance technique at local (few hectares) scale. Regional inversions at 0.5{sup 0} resolution are applied for the western European domain where {approx}50 eddy covariance sites are operated. These inversions are conducted for the period 2002-2007. They use a mesoscale atmospheric transport model, a prior estimate of the NEE from a terrestrial ecosystem model and rely on the variational assimilation of in situ continuous measurements of CO2 atmospheric mole fractions. Averaged over monthly periods and over the whole domain, the misfits are in good agreement with the theoretical uncertainties for prior and inverted NEE, and pass the chi-square test for the variance at the 30% and 5% significance levels respectively, despite the scale mismatch and the independence between the prior (respectively inverted) NEE and the flux measurements. The theoretical uncertainty reduction for the monthly NEE at the measurement sites is 53% while the inversion decreases the standard deviation of the misfits by 38 %. These results build confidence in the NEE estimates at the European/monthly scales and in their theoretical uncertainty from the regional inverse modelling system. However, the uncertainties at the monthly (respectively annual) scale remain larger than the amplitude of the inter-annual variability of monthly (respectively annual) fluxes, so that this study does not engender confidence in the inter-annual variations. The uncertainties at the monthly scale are significantly smaller than the seasonal variations. The seasonal cycle of the inverted fluxes is thus reliable. In particular, the CO2 sink period over the European continent likely ends later than

  12. Uncertainties in the daily operation of a district heating plant

    DEFF Research Database (Denmark)

    Sorknæs, Peter

    Studies have found that district heating (DH) systems should play an important role in future sustainable energy systems, but that DH has to adapt to lower heat demands. This means adapting to reduced operation hours for units essential for DHs integration in other parts of the energy system......, such as CHP. It will therefore likely be increasingly important to increase the value per operation hour. The value can be increased by offering balancing for the electricity system. This in turn increases the uncertainties in the daily operation planning of the DH system. In this paper the Danish DH plant...... Ringkøbing District Heating is used as a case to investigate what costs market uncertainties can incur on a DH plant. It is found that the market uncertainties in a 4 months simulated period increased Ringkøbing District Heatings costs by less than 1%. Several factors are however not included in this paper....

  13. Scalability of a Methodology for Generating Technical Trading Rules with GAPs Based on Risk-Return Adjustment and Incremental Training

    Science.gov (United States)

    de La Cal, E. A.; Fernández, E. M.; Quiroga, R.; Villar, J. R.; Sedano, J.

    In previous works a methodology was defined, based on the design of a genetic algorithm GAP and an incremental training technique adapted to the learning of series of stock market values. The GAP technique consists in a fusion of GP and GA. The GAP algorithm implements the automatic search for crisp trading rules taking as objectives of the training both the optimization of the return obtained and the minimization of the assumed risk. Applying the proposed methodology, rules have been obtained for a period of eight years of the S&P500 index. The achieved adjustment of the relation return-risk has generated rules with returns very superior in the testing period to those obtained applying habitual methodologies and even clearly superior to Buy&Hold. This work probes that the proposed methodology is valid for different assets in a different market than previous work.

  14. 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

  15. 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.

  16. 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.

  17. Analysis of the influence of input data uncertainties on determining the reliability of reservoir storage capacity

    Directory of Open Access Journals (Sweden)

    Marton Daniel

    2015-12-01

    Full Text Available The paper contains a sensitivity analysis of the influence of uncertainties in input hydrological, morphological and operating data required for a proposal for active reservoir conservation storage capacity and its achieved values. By introducing uncertainties into the considered inputs of the water management analysis of a reservoir, the subsequent analysed reservoir storage capacity is also affected with uncertainties. The values of water outflows from the reservoir and the hydrological reliabilities are affected with uncertainties as well. A simulation model of reservoir behaviour has been compiled with this kind of calculation as stated below. The model allows evaluation of the solution results, taking uncertainties into consideration, in contributing to a reduction in the occurrence of failure or lack of water during reservoir operation in low-water and dry periods.

  18. 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 ...

  19. Returns Effect, Shocks and Volatility Transmission between Foreign Exchange-Stock Markets in Nigeria

    Directory of Open Access Journals (Sweden)

    Agya Atabani Adi

    2017-03-01

    Full Text Available The paper examined effect of passed return on current return, shocks spillover and volatility transmission between FX-Stock markets. Using result obtained from VAR-GARCH models, we also calculate the optimal weight and risk minimizing hedging ratio for FX-Stock markets and employed the newly developed bivariate GARCH framework Findings reveal evidence of short term predictability in both markets through time. One period lagged returns significantly impact current return in both markets, and impact was greater in FX market both VAR-GARCH and VAR-AGARCH models. There were evidence of bi-directional volatility transmission in both markets and uni-directional shocks spillover from stock to FX market in both models. VAR-AGARCH model showed evidence of leverage effect; bad news has more impact on volatility than positive news of the same magnitude. We showed that optimal polio of FX-Stock market should holds more foreign exchange to stocks in their asset polio. Our result showed evidence of effective hedging in FX-Stock markets in Nigerian. Hence, the inclusion of stocks in diversified polio of foreign exchange could improve it risks adjusted performance of hedging ratio.

  20. 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.