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Multivariate hydrological series become nonstationary under the changing environment. In this paper, a new method is proposed to study the change in the dependence structure between runoff and sediment sequences. First, a moving cut transfer entropy is proposed to detect the sudden change point in the dependence structure between runoff and sediment. Then, the Gumbel copula with a new parameter estimation method (MEE) is employed to construct the dependence structure of runoff and sediment before or after the change point for situation with small samples. The new method is applied to the annual runoff and sediment discharge series in Xiliugou River, China. It is found that the dependence structure between runoff and sediment changed abruptly in 2000. The joint probabilistic characteristics of the annual runoff and sediment discharge during the period of 1960–1999 are built based on the values of RMSEs and AICs. The joint distribution of the annual runoff and sediment discharge during the period of 2000–2016 is constructed by the Gumbel copula with MEE. Moreover, the synchronous encounter probability of runoff and sediment decreases from 0.76 to 0.63, and the asynchronous encounter probability rises from 0.24 to 0.37, after the runoff and sediment discharge series presents a significant change in the dependence structure. [ABSTRACT FROM AUTHOR]

The hydrologic data series are nonstationary due to climate change and local anthropogenic activities. The existing nonstationary design flood estimation methods usually focus on the statistical nonstationarity of the flow data series in the catchment, which neglect the hydraulic approach, such as reservoir flood regulation. In this paper, a novel approach to comprehensively consider the driving factors of non-stationarities in design flood estimation is proposed, which involves three main steps: (1) implementation of the candidate predictors with trend tests and change point detection for preliminary analysis; (2) application of the nonstationary flood frequency analysis with the principle of Equivalent Reliability (ER) for design flood volumes; (3) development of a nonstationary most likely regional composition (NS-MLRC) method, and the estimation of a design flood hydrograph at downstream cascade reservoirs. The proposed framework is applied to the cascade reservoirs in the Han River, China. The results imply that: (1) the NS-MLRC method provides a much better explanation for the nonstationary spatial correlation of the flood events in Han River basin, and the multiple nonstationary driving forces can be precisely quantified by the proposed design flood estimation framework; (2) the impacts of climate change and population growth are long-lasting processes with significant risk of flood events compared with stationary distribution conditions; and (3) the swift effects of cascade reservoirs are reflected in design flood hydrographs with lower peaks and lesser volumes. This study can provide a more integrated template for downstream flood risk management under the impact of climate change and human activities. [ABSTRACT FROM AUTHOR]

Purpose: Based on structural embeddedness theory and resource dependence theory, this research aims to examine the mediation role of information sharing in the relationship between deendency structures and electronic supply chain management system (eSCM) adoption and a firm's intention to adopt eSCMs. Design/methodology/approach: A survey questionnaire was undertaken from 212 companies based in Mainland China. Three-stage least squares (3SLS) regression was employed to test the research model. Findings: The results from 3SLS regressions showed that the effect of interdependence on eSCM adoption intention is fully mediated through information sharing when relationship duration is either below or about the mean. Interdependence and dependence disadvantage was shown to have significant positive effects on eSCM adoption while the effect of dependence advantage was statistically insignificant. Relationship duration was found to negatively moderate the relationship between information sharing and adoption intention. Originality/value: Through investigating factors of inter-organizational relationships, this study fills the knowledge gap in the traditional paradigms which ignore the collaborative nature of eSCM and analyse related problems based on a single firm's point of view. [ABSTRACT FROM AUTHOR]

To qualify niche space and niche overlap, the current methods are based on a strict assumption of the normal distribution and restrict dependence to the linear structure between resource axes. In this study, we propose a new method for measuring the stoichiometric niche space and niche overlap based on copula theory. Our method does not require the resource axes to obey the multivariate normal distribution and only assumes that each dimension of resource availability follows a one-dimensional normal distribution. Based on the dependence structure presented by the three resource axes, an appropriate copula is selected to couple the normal assumptions and thus determine a joint distribution that fits the carbon, nitrogen and phosphorus concentration data. Additional simulation studies were conducted to calculate niche space and niche overlap. We applied our method to qualify the stoichiometric niche space and niche overlap between seven grassland plants in Inner Mongolia, North China. Our results demonstrate that, except for a positive correlation, symmetrical tail correlations existed between nitrogen and phosphorus concentrations, which had a significant influence on the shape of the niche space. The new method presented in our work extends types of joint distribution fitting resource axes from a multivariate normal distribution to an arbitrary joint distribution determined by copulas and normal margins, and it has the advantage of describing the complex dependence between resource axes. [ABSTRACT FROM AUTHOR]