Statistical Characterization of Environmental Hot Spots and Hot Moments and Applications in Groundwater Hydrology

Abstract. Environmental hot spots and hot moments (HSHMs) represent rare locations and events that exert disproportionate influence over the environment. While several mechanistic models have been used to characterize HSHM behavior at specific sites, a critical missing component of research on HSHMs has been the development of clear, conventional statistical models. In this paper, we introduced a novel stochastic framework for analyzing HSHMs and the uncertainties. This framework can easily incorporate heterogeneous features into the spatiotemporal domain and can offer inexpensive solutions for testing future scenarios. The proposed approach utilizes indicator random variables (RVs) to construct a statistical model for HSHMs. The HSHM indicator RVs are comprised of spatial and temporal components, which can be used to represent the unique characteristics of HSHMs. We identified three categories of HSHMs and demonstrated how our statistical framework is adjusted for each category. The three categories are (1) HSHMs defined only by spatial (static) components, (2) HSHMs defined by both spatial and temporal (dynamic) components, and (3) HSHMs defined by multiple dynamic components. The representation of an HSHM through its spatial and temporal components allows researchers to relate the HSHM's uncertainty to the uncertainty of its components. We illustrated the proposed statistical framework through several HSHM case studies covering a variety of surface, subsurface, and coupled systems.

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Statistical Characterization of Environmental Hot Spots and Hot Moments and Applications in Groundwater Hydrology

10.5194/hess-2020-343 ◽

2020 ◽

Author(s):

Jiancong Chen ◽

Bhavna Arora ◽

Alberto Bellin ◽

Yoram Rubin

Keyword(s):

Hot Spots ◽

Coupled Systems ◽

Groundwater Hydrology ◽

Temporal Dynamic ◽

Statistical Characterization ◽

Statistical Framework ◽

Heterogeneous Features ◽

Stochastic Framework ◽

Dynamic Components

Abstract. Environmental hot spots and hot moments (HSHMs) represent rare locations and events that exert disproportionate influence over the environment. While several mechanistic models have been used to characterize HSHMs behavior at specific sites, a critical missing component of research on HSHMs has been the development of clear, conventional statistical models. In this paper, we introduced a novel stochastic framework for analyzing HSHMs and the uncertainties. This framework can easily incorporate heterogeneous features in the spatiotemporal domain and can offer inexpensive solutions for testing future scenarios. The proposed approach utilizes indicator random variables (RVs) to construct a statistical model for HSHMs. The HSHMs indicator RVs are comprised of spatial and temporal components, which can be used to represent the unique characteristics of HSHMs. We identified three categories of HSHMs and demonstrated how our statistical framework are adjusted for each category. The three categories are (1) HSHMs defined only by spatial (static) components, (2) HSHMs defined by both spatial and temporal (dynamic) components, and (3) HSHMs defined by multiple dynamic components. The representation of an HSHM through its spatial and temporal components allows researchers to relate the HSHM’s uncertainty to the uncertainty of its components. We illustrated the proposed statistical framework through several HSHM case studies covering a variety of surface, subsurface, and coupled systems.

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Statistical Characterization of Harmonic Emissions in Power Supply Systems

International Review of Electrical Engineering (IREE) ◽

10.15866/iree.v9i4.1099 ◽

2014 ◽

Vol 9 (4) ◽

pp. 803 ◽

Cited By ~ 4

Author(s):

Diego Bellan

Keyword(s):

Power Supply ◽

Statistical Characterization ◽

Supply Systems

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Statistical Characterization of Fish School Clutter

10.21236/ada472811 ◽

2007 ◽

Author(s):

Timothy K. Stanton ◽

Dezhang Chu

Keyword(s):

Statistical Characterization ◽

Fish School

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Critical Review of EMC Standards for the Measurement of Radiated Electromagnetic Emissions from Transit Line and Rolling Stock

Energies ◽

10.3390/en14030759 ◽

2021 ◽

Vol 14 (3) ◽

pp. 759

Author(s):

Andrea Mariscotti

Keyword(s):

Time Distribution ◽

Communication Systems ◽

Electromagnetic Compatibility ◽

Transportation Systems ◽

Operating Conditions ◽

Rolling Stock ◽

Intrinsic Variability ◽

Statistical Characterization ◽

Electromagnetic Emissions

Accurate and comprehensive methods for the assessment of radiated electromagnetic emissions in modern electric transportation systems are a necessity. The characteristics and susceptibility of modern victim signaling and communication radio services, operating within and outside the right-of-way, require an update of the measurement methods integrating or replacing the swept frequency technique with time domain approaches. Applicable standards are the EN 50121 (equivalent to the IEC 62236) and Urban Mass Transport Association (UMTA) with additional specifications from project contracts. This work discusses the standardized methods and settings, and the representative operating conditions, highlighting areas where improvements are possible and opportune (statistical characterization of measurement results, identification and distinction of emissions and line resonances, and narrowband and broadband phenomena). In particular for the Electromagnetic Compatibility (EMC) assessment with new Digital Communication Systems, the characterization of time distribution of spectral properties is discussed, e.g., by means of Amplitude Probability Distribution and including time distribution information. The problem of determination of site and setup uncertainty and repeatability is also discussed, observing on one hand the lack of clear indications in standards and, on the other hand, the non-ideality and intrinsic variability of measurement conditions (e.g., rolling stock operating conditions, synchronization issues, and electric arc intermittence).

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