scholarly journals A New Uncertainty Measure for Assessing the Uncertainty Existing in Hydrological Simulation

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 812 ◽  
Author(s):  
Pengfei Shi ◽  
Tao Yang ◽  
Bin Yong ◽  
Zhenya Li ◽  
Chong-Yu Xu ◽  
...  
Keyword(s):  
Information Matrix ◽  
Uncertainty Assessment ◽  
Performance Comparison ◽  
Uncertainty Measure ◽  
Behavioral Measures ◽  
Hydrological Simulation ◽  
Uncertainty Index ◽  
Pairwise Correlations ◽  
Glue Method ◽  
Selection Of

The absence of aggregated uncertainty measures restricts the assessment of uncertainty in hydrological simulation. In this work, a new composite uncertainty measure is developed to evaluate the complex behaviors of uncertainty existing in hydrological simulation. The composite uncertainty measure is constructed based on a framework, which includes three steps: (1) identification of behavioral measures by analyzing the pairwise correlations among different measures and removing high correlations; (2) weight assignment by means of a new hierarchical weight assembly (HWA) approach incorporating the intra-class and inter-class weights; (3) construction of a composite uncertainty measure through incorporating multiple properties of the measure matrix. The framework and the composite uncertainty measure are demonstrated by case studies in uncertainty assessment for hydrological simulation. Results indicate that the framework is efficient to generate a composite uncertainty index (denoted as CUI) and the new measure CUI is competent for uncertainty evaluation. Besides, the HWA approach performs well in weighting, which can characterize subjective and objective properties of the information matrix. The achievement of this work provides promising insights into the performance comparison of uncertainty analysis approaches, the selection of proper cut-off threshold in the GLUE method, and the guidance of reasonable uncertainty assessment in a range of environmental modelling.

scholarly journals Uncertainty Assessment of Urban Hydrological Modelling from a Multiple Objective Perspective

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1393 ◽  
Author(s):  
Bo Pang ◽  
Shulan Shi ◽  
Gang Zhao ◽  
Rong Shi ◽  
Dingzhi Peng ◽  
...  
Keyword(s):  
Flood Management ◽  
Uncertainty Assessment ◽  
Multiple Objective ◽  
Hydrological Models ◽  
Validation Period ◽  
Urban Flood ◽  
Calibration Period ◽  
Storm Water Management Model ◽  
Glue Method ◽  
Generalized Likelihood Uncertainty Estimation

The uncertainty assessment of urban hydrological models is important for understanding the reliability of the simulated results. To satisfy the demand for urban flood management, we assessed the uncertainty of urban hydrological models from a multiple-objective perspective. A multiple-criteria decision analysis method, namely, the Generalized Likelihood Uncertainty Estimation-Technique for Order Preference by Similarity to Ideal Solution (GLUE-TOPSIS) was proposed, wherein TOPSIS was adopted to measure the likelihood within the GLUE framework. Four criteria describing different urban stormwater characteristics were combined to test the acceptability of the parameter sets. The TOPSIS was used to calculate the aggregate employed in the calculation of the aggregate likelihood value. The proposed method was implemented in the Storm Water Management Model (SWMM), which was applied to the Dahongmen catchment in Beijing, China. The SWMM model was calibrated and validated based on the three and two flood events respectively downstream of the Dahongmen catchment. The results showed that the GLUE-TOPSIS provided a more precise uncertainty boundary compared with the single-objective GLUE method. The band widths were reduced by 7.30 m3/s in the calibration period, and by 7.56 m3/s in the validation period. The coverages increased by 20.3% in the calibration period, and by 3.2% in the validation period. The median estimates improved, with an increase of the Nash–Sutcliffe efficiency coefficients by 1.6% in the calibration period, and by 10.0% in the validation period. We conclude that the proposed GLUE-TOPSIS is a valid approach to assess the uncertainty of urban hydrological model from a multiple objective perspective, thereby improving the reliability of model results in urban catchment.

Advances in Measurement of Indoor 222Rn and 220Rn Gas Concentrations Using Solid State Nuclear Track Detectors

2015 ◽  
Vol 238 ◽  
pp. 116-126 ◽  
Author(s):  
B.K. Sahoo ◽  
B.K. Sapra
Keyword(s):  
Cost Effectiveness ◽  
Solid State ◽  
Field Experiments ◽  
Performance Comparison ◽  
Mode Ii ◽  
New Device ◽  
Nuclear Track Detectors ◽  
Radon Measurements ◽  
Selection Of ◽  
Radon Monitoring

Solid State Nuclear Track Detectors (SSNTDs) have been widely used for time integrated radon measurements due to their cost effectiveness, portability and easy-to-use feature. In order to obtain a proper measurement of radon using SSNTDs, it is necessary to select a proper exposure mode. The various modes in which the SSNTDs can be exposed are: (i) bare mode, (ii) single cup mode, and (iii) twin cup mode. This paper addresses the merits and demerits of SSNTDs used in each type of mode of exposure for radon monitoring. The paper analyses the results of the conventional bare mode as well as the latest twin cup mode of SSNTDs. The paper also analyses the performance comparison of single entrance vis a vis double entrance type twin cup dosimeter. Design and features of the newly developed pinhole based single entrance twin cup dosimeter have been discussed. A protocol has been proposed for the selection of houses and deployment of the dosimeter. Some of the important findings from laboratory and field experiments of the new device have been presented.

scholarly journals D-Optimal Sequential Sampling Designs for Item Response Theory Models

1994 ◽  
Vol 19 (1) ◽  
pp. 43-56 ◽  
Author(s):  
Martijn P.F. Berger
Keyword(s):  
Item Response ◽  
Sequential Sampling ◽  
Information Matrix ◽  
Design Procedure ◽  
Sequential Design ◽  
Optimal Designs ◽  
Unknown Parameters ◽  
Irt Models ◽  
Item Response Theory Models ◽  
Selection Of

The selection of optimal designs in IRT models encounters at least two problems. The first problem is that Fisher’s information matrix is generally not independent of the values of the IRT parameters, and the second problem is that the design points are unknown parameters and have to be estimated together with the other parameters. In this study, these two problems are taken care of by a sequential design procedure. This procedure is a modification of a D-optimality procedure proposed by Wynn (1970) . The results show that this algorithm leads to consistent estimates and that errors in selecting the abilities generally do not affect optimality very much.

scholarly journals A Novel Fuzzy Encryption Technique Based on Multiple Right Translated AES Gray S-Boxes and Phase Embedding

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Naveed Ahmed Azam
Keyword(s):  
Image Encryption ◽  
State Of The Art ◽  
Performance Comparison ◽  
Security System ◽  
Security Systems ◽  
Secret Image ◽  
Host Image ◽  
Embedding Technique ◽  
Frequency Domains ◽  
Selection Of

This paper presents a novel image encryption technique based on multiple right translated AES Gray S-boxes (RTSs) and phase embedding technique. First of all, a secret image is diffused with a fuzzily selected RTS. The fuzzy selection of RTS is variable and depends upon pixels of the secret image. Then two random masks are used to enhance confusion in the spatial and frequency domains of the diffused secret image. These random masks are generated by applying two different RTSs on a host image. The decryption process of the proposed cryptosystem needs the host image for generation of masks. It is therefore, necessary, to secure the host image from unauthorized users. This task is achieved by diffusing the host image with another RTS and embedding the diffused secret image into the phase terms of the diffused host image. The cryptographic strength of the proposed security system is measured by implementing it on several images and applying rigorous analyses. Performance comparison of the proposed security technique with some of the state-of-the-art security systems, including S-box cryptosystem and steganocryptosystems, is also performed. Results and comparison show that the newly developed cryptosystem is more secure.

An Improved PSO Algorithm of Optimizing Selection for Multi-Objective Controller Parameter

2013 ◽  
Vol 401-403 ◽  
pp. 1805-1808
Author(s):  
Yan Juan Ren
Keyword(s):  
Performance Index ◽  
Pid Controller ◽  
Research Result ◽  
Pso Algorithm ◽  
Performance Comparison ◽  
Control Effect ◽  
Global Optimal ◽  
Selection For ◽  
Selection Of ◽  
Improved Pso

For the same controlled process, different controller is radically different in control effect. Aimed at the puzzle of being difficult to select the controller for the incompatibility among control performance index, the paper proposed a sort of improved PSO algorithm. Based on the construction of objective function in multi-performance index parameter, the algorithm could quickly search and converge to control parameter in global optimal extremum corresponded to each controller and single out the controller through performance comparison excellently. In the paper, it took the controller selection of wastewater treatment system as an example, designed the algorithm of multi-modal HSIC controller of DO parameter, made the experiment of system simulation, and the simulation demonstrated that the HSIC controller could be stronger in robustness and better in dynamical and steady control quality compared with improved PID controller. The research result shows that it is reasonable and applicable to optimize selection of controller.

scholarly journals Building a Knowledge Base for the Model

2021 ◽  
pp. 51-70
Author(s):  
Sarah Nurse ◽  
Jakub Bijak
Keyword(s):  
Research Process ◽  
Uncertainty Assessment ◽  
Data Sources ◽  
Migration Route ◽  
Data Types ◽  
Formal Modelling ◽  
Proposed Model ◽  
History Of ◽  
Selection Of

AbstractIn this chapter, after summarising the key conceptual challenges related to the measurement of asylum migration, we briefly outline the history of recent migration flows from Syria to Europe. This case study is intended to guide the development of a model of migration route formation, used throughout this book as an illustration of the proposed model-based research process. Subsequently, for the case study, we offer an overview of the available data types, making a distinction between the sources related to the migration processes, as well as to the context within which migration occurs. We then propose a framework for assessing different aspects of data, based on a review of similar approaches suggested in the literature, and this framework is subsequently applied to a selection of available data sources. The chapter concludes with specific recommendations for using the different forms of data in formal modelling, including in the uncertainty assessment.

Planning of refracted starlight observation based on observability analysis

2021 ◽  
pp. 095441002110301
Author(s):  
Chengzhen Wu ◽  
Xueying An ◽  
Dingjie Wang ◽  
Hongbo Zhang
Keyword(s):  
Fisher Information ◽  
Information Matrix ◽  
Quantitative Relationship ◽  
Navigation Problem ◽  
Information Index ◽  
Observability Analysis ◽  
Observation Sequence ◽  
Fisher Information Index ◽  
Selection Of ◽  
Observation Scheme

In traditional observation schemes of stellar refraction navigation, the accuracy was limited due to unreasonable observation directions. In order to ameliorate this situation, a method of refracted starlight observation based on observability analysis is proposed. The function of this method is optimally generating an observation attitude sequence according to standard trajectories of spacecraft so that the selection of a refracted starlight observation sequence can be realized. Specifically, the improvement of Fisher information matrix calculation enables this method to be qualified for the navigation problem with unsteady measurement quantities as well as the non-fully observability which is defined as the capability of estimating the system state through measurements in finite time. Here, we construct a quantitative relationship between refracted starlight measurements and system observability by means of Fisher information index ( FII). Next, the observation scheme is retrieved by searching the maximum value of the optimized variable, which includes the ( FII). Finally, we resort to the extended Kalman filter to accomplish typical trajectory navigation simulations of the observation scheme. The results indicate that our method brings more accuracy than traditional ones in estimation of position and velocity of the optimal observation scheme.

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