Uncertainty in flood discharges from urban and small rural catchments due to inaccurate head measurement

2005 ◽  
Vol 36 (3) ◽  
pp. 245-257 ◽  
Author(s):  
A. Petersen-Øverleir ◽  
T. Reitan

Despite frequent use of estimated flood discharges from urban and small rural catchments, the assessment of uncertainty in instantaneous discharge due to inaccurate head measurements is generally not performed. The present work discusses the impact of inaccurate head measurement on observed instantaneous flood discharge. The sources and sizes of uncertainties in head determination are discussed. A simple uncertainty model is developed in order to quantify the uncertainty in error-corrupted instantaneous and mean discharge. It is shown that uncertainty in mean discharge is less affected by uncorrelated head measurement error, while instantaneous discharges are substantially affected. Practical modelling using data from a Norwegian urban gauging station is undertaken. It is shown that the estimated annual maximum instantaneous flood discharge from this watershed has 95% confidence limits with sizes of 17–19% of the estimated discharge for average head measurement accuracy. Furthermore, it is shown that variability in head determination causes only a minor potential for bias in estimated instantaneous flood population statistics and quantiles.

2017 ◽  
Vol 3 ◽  
pp. e135 ◽  
Author(s):  
Jasmin Ramadani ◽  
Stefan Wagner

Background Software maintenance is an important activity in the development process where maintenance team members leave and new members join over time. The identification of files which are changed together frequently has been proposed several times. Yet, existing studies about coupled file changes ignore the feedback from developers as well as the impact of these changes on the performance of maintenance and rather these studies rely on the analysis findings and expert evaluation. Methods We investigate the usefulness of coupled file changes during perfective maintenance tasks when developers are inexperienced in programming or when they were new on the project. Using data mining on software repositories we identify files that are changed most frequently together in the past. We extract coupled file changes from the Git repository of a Java software system and join them with corresponding attributes from the versioning and issue tracking system and the project documentation. We present a controlled experiment involving 36 student participants in which we investigate if coupled file change suggestions influence the correctness of the task solutions and the required time to complete them. Results The results show that the use of coupled file change suggestions significantly increases the correctness of the solutions. However, there is only a minor effect on the time required to complete the perfective maintenance tasks. We also derived a set of the most useful attributes based on the developers’ feedback. Discussion Coupled file changes and a limited number of the proposed attributes are useful for inexperienced developers working on perfective maintenance tasks where although the developers using these suggestions solved more tasks, they still need time to understand and organize this information.


Author(s):  
Brynne D. Ovalle ◽  
Rahul Chakraborty

This article has two purposes: (a) to examine the relationship between intercultural power relations and the widespread practice of accent discrimination and (b) to underscore the ramifications of accent discrimination both for the individual and for global society as a whole. First, authors review social theory regarding language and group identity construction, and then go on to integrate more current studies linking accent bias to sociocultural variables. Authors discuss three examples of intercultural accent discrimination in order to illustrate how this link manifests itself in the broader context of international relations (i.e., how accent discrimination is generated in situations of unequal power) and, using a review of current research, assess the consequences of accent discrimination for the individual. Finally, the article highlights the impact that linguistic discrimination is having on linguistic diversity globally, partially using data from the United Nations Educational, Scientific and Cultural Organization (UNESCO) and partially by offering a potential context for interpreting the emergence of practices that seek to reduce or modify speaker accents.


Methodology ◽  
2007 ◽  
Vol 3 (1) ◽  
pp. 14-23 ◽  
Author(s):  
Juan Ramon Barrada ◽  
Julio Olea ◽  
Vicente Ponsoda

Abstract. The Sympson-Hetter (1985) method provides a means of controlling maximum exposure rate of items in Computerized Adaptive Testing. Through a series of simulations, control parameters are set that mark the probability of administration of an item on being selected. This method presents two main problems: it requires a long computation time for calculating the parameters and the maximum exposure rate is slightly above the fixed limit. Van der Linden (2003) presented two alternatives which appear to solve both of the problems. The impact of these methods in the measurement accuracy has not been tested yet. We show how these methods over-restrict the exposure of some highly discriminating items and, thus, the accuracy is decreased. It also shown that, when the desired maximum exposure rate is near the minimum possible value, these methods offer an empirical maximum exposure rate clearly above the goal. A new method, based on the initial estimation of the probability of administration and the probability of selection of the items with the restricted method ( Revuelta & Ponsoda, 1998 ), is presented in this paper. It can be used with the Sympson-Hetter method and with the two van der Linden's methods. This option, when used with Sympson-Hetter, speeds the convergence of the control parameters without decreasing the accuracy.


2020 ◽  
Vol 51 (2) ◽  
pp. 135-140 ◽  
Author(s):  
Maykel Verkuyten ◽  
Kumar Yogeeswaran

Abstract. Multiculturalism has been criticized and rejected by an increasing number of politicians, and social psychological research has shown that it can lead to outgroup stereotyping, essentialist thinking, and negative attitudes. Interculturalism has been proposed as an alternative diversity ideology, but there is almost no systematic empirical evidence about the impact of interculturalism on the acceptance of migrants and minority groups. Using data from a survey experiment conducted in the Netherlands, we examined the situational effect of promoting interculturalism on acceptance. The results show that for liberals, but not for conservatives, interculturalism leads to more positive attitudes toward immigrant-origin groups and increased willingness to engage in contact, relative to multiculturalism.


2020 ◽  
Vol 17 (3) ◽  
pp. 445-460
Author(s):  
Mohd Imran Khan ◽  
Valatheeswaran C.

The inflow of international remittances to Kerala has been increasing over the last three decades. It has increased the income of recipient households and enabled them to spend more on human capital investment. Using data from the Kerala Migration Survey-2010, this study analyses the impact of remittance receipts on the households’ healthcare expenditure and access to private healthcare in Kerala. This study employs an instrumental variable approach to account for the endogeneity of remittances receipts. The empirical results show that remittance income has a positive and significant impact on households’ healthcare expenditure and access to private healthcare services. After disaggregating the sample into different heterogeneous groups, this study found that remittances have a greater effect on lower-income households and Other Backward Class (OBC) households but not Scheduled Caste (SC) and Scheduled Tribe (ST) households, which remain excluded from reaping the benefit of international migration and remittances.


Author(s):  
Guoliang Yang ◽  
Zhihua Wang ◽  
Weijiong Wu

Little is known about the relationship between social comparison orientation and mental health, especially in the psychological capital context. We proposed a theoretical model to examine the impact of ability- and opinion-based social comparison orientation on mental health using data from 304 undergraduates. We also examined the mediating effect of the four psychological capital components of hope, self-efficacy, resilience, and optimism in the relationship between social comparison orientation and mental health. Results show that an ability (vs. opinion) social comparison orientation was negatively (vs. positively) related to the psychological capital components. Further, the resilience and optimism components of psychological capital fully mediated the social comparison orientation–mental health relationship. Our findings indicate that psychological capital should be considered in the promotion of mental health, and that the two social comparison orientation types have opposite effects on psychological capital.


2017 ◽  
Vol 921 (3) ◽  
pp. 7-13 ◽  
Author(s):  
S.V. Grishko

This paper shows that the accuracy of relative satellite measurements depend not only on the length of the baseline, as it is regulated by the rating formula of accuracy of GNSS equipment, but also on the duration of observations. As a result of the strict adjustment much redundant satellite networks with different duration of observations obtained covariance matrix of baselines, the most realistic reflecting the actual error of satellite observations. Research of forms of communication of these errors from length of the baseline and duration of its measurement is executed. A significant influence of solar activity on accuracy of satellite measurements, in general, leads to unequal similar series of measurements made at different periods, for example, in the production of monitoring activities. The model of approximation of the functional dependence of accuracy of the baseline from its length and duration of observations having good qualitative characteristics is offered. Based on the proposed model, we analyzed the dynamics of changes in measurement accuracy with an increase in observation time.


2020 ◽  
Vol 33 (13) ◽  
Author(s):  
Inês Laplanche Coelho ◽  
Mafalda Sousa-Uva ◽  
Nuno Pina ◽  
Sara Marques ◽  
Carlos Matias-Dias ◽  
...  

Introduction: Previous studies have found an increase in the incidence rate of depression between 2007 – 2013 in Portugal, with a positive correlation with the unemployment rate, namely, in men. So, it was hypothesized that this increase is related with the situation of economic crisis. This study aimed to investigate if the correlation between unemployment rates and the incidence of depression is maintained in the post-crisis period of economic recovery in Portugal (2016 – 2018).Material and Methods: An ecological study was carried out, using data from the General Practitioners Sentinel Network concerning depression incidence (first episodes and relapses) and data from the National Statistics Institute on unemployment rates in the Portuguese population. The correlation coefficient was estimated using linear regression and the results were disaggregated by sex.Results: Between 2016 and 2018, there was a consistent decrease in the incidence of depression in both sexes. During the 1995 – 2018 period, a positive correlation was observed between unemployment and depression, with a coefficient of 0.833 (p = 0.005) in males and of 0.742 (p = 0.022) in females.Discussion: The reduction in the incidence of depression in both sexes observed between 2016 – 2018 corroborates a positive correlation between unemployment and depression in the Portuguese population, previously observed between 2007 – 2013.Conclusion: This study highlights the need to monitor the occurrence of mental illness in the Portuguese population, especially in moments of greatest social vulnerability in order to establish preventive measures, as a way to mitigate the impact of future economic crises.


2021 ◽  
Vol 17 (2) ◽  
pp. 412-428
Author(s):  
Hilla Peretz ◽  
Michael J. Morley

ABSTRACTWe offer a preliminary examination of whether national and organizational level contexts amplify or reduce the effects of de-globalization on the performance of MNCs. Theoretically, we borrow ideas from both event system theory and institutional fit to propose a model explicating key dimensions of the relationship between de-globalization, national and organizational context, and MNC performance. We then test our ideas using data assembled from 283 MNCs in 20 countries. We find that while de-globalization has a negative effect on MNC performance, national and organizational level contextual endowments do moderate this relationship. We discuss some implications of our findings and highlight attendant limitations.


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