scholarly journals Uncertainty Reduction in Logistic Growth Regression Using Surrogate Systems Carrying Capacities: a COVID-19 Case Study

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Bruno Hebling Vieira ◽  
Nathalia Hanna Hiar ◽  
George C. Cardoso
Keyword(s):  
Uncertainty Reduction ◽  
Logistic Growth ◽  
Surrogate Systems ◽  
Growth Regression

A Stochastic Framework to Optimize the Monitoring Strategy for the Delineation of a Groundwater Divide

2020 ◽  
Author(s):  
Jonas Allgeier ◽  
Ana Gonzalez-Nicolas ◽  
Daniel Erdal ◽  
Wolfgang Nowak ◽  
Olaf A. Cirpka
Keyword(s):  
Surface Water ◽  
Value Of Information ◽  
Hydraulic Head ◽  
Uncertainty Reduction ◽  
West Germany ◽  
Added Value ◽  
Flow Models ◽  
Digital Elevation ◽  
Stochastic Framework

<p>The boundaries of surface-water catchments can be delineated by analyzing digital elevation models using geographic information systems. Surface-water divides and groundwater divides, however, might significantly differ from each other because the groundwater surface does not necessarily follow the surface topography. Hydraulic-head measurements are needed to properly delineate a groundwater divide and thereby the subsurface boundary of a catchment, but piezometers are expensive. It is therefore vital to optimize the placement of the necessary piezometers. In this work, we introduce an optimal design analysis, which can identify the best configuration of potential piezometer placements within a given set. The method is based on the formal minimization of the expected posterior uncertainty within a sampling-based Bayesian framework. It makes use of a random ensemble of behavioral steady-state groundwater flow models. For each behavioral realization we compute virtual hydraulic-head measurements at all potential well points and delineate the groundwater divide by particle tracking. We minimize the uncertainty of the groundwater-divide location by marginalizing over the virtual measurements. We test the method mimicking a real aquifer in South-West Germany. Previous works in this aquifer indicated a groundwater divide that is shifted compared to the surface-water divide. The analysis shows that the uncertainty in the localization of the groundwater divide can be reduced with each new well. A comparison of the maximum uncertainty reduction at different numbers of wells quantifies the added value of information for each new well. In our case study, the uncertainty reduction obtained by three monitoring points is maximized when the first well is close to the topographic surface water divide, the second one in the valley, and the third one in between. </p>

CMM Measurement Uncertainty Reduction via Sampling Strategy Optimization

2008 ◽  
Author(s):  
Giovanni Moroni ◽  
Stefano Petro`
Keyword(s):  
Measurement Uncertainty ◽  
Measurement Errors ◽  
Coordinate Measuring Machine ◽  
Sampling Strategy ◽  
Uncertainty Reduction ◽  
Repeated Measurements ◽  
Trade Off ◽  
Geometrical Error ◽  
Measuring Machine

Uncertainty is a key concept in any environment which involves measurements to ensure process quality: a trade-off has to be found between measurement costs, which increase as uncertainty lowers, and costs related to measurement errors. In mechanics, geometrical conformance is a common requirement. Two similar standards series deal with the problem of uncertainty in geometrical error estimate: ASME B89.7.3 and ISO 14253. Geometrical inspection is often performed by means of a “Coordinate Measuring Machine” (CMM). For a CMM, a trade off between measurement and errors costs may be found by optimizing the sampling strategy. In this work a cost function will be proposed as support for finding a trade-off between measurement uncertainty and costs. This function may be optimized by means of an heuristic algorithm. The method will involve repeated measurements of calibrated parts to evaluate uncertainty (like in ISO/TS 15330-3). A case study will be proposed.

scholarly journals Modeling the COVID-19 spread, a case study of Egypt

2021 ◽  
Vol 29 (1) ◽  
Author(s):  
Assem S. Deif ◽  
Sahar A. El-Naggar
Keyword(s):  
Sir Model ◽  
Logistic Growth ◽  
Approximate Estimate ◽  
Epidemic Size ◽  
Final Epidemic Size ◽  
Logistic Growth Model ◽  
Reported Data ◽  
High Degree ◽  
Second Wave

AbstractIn this article, the authors applied a logistic growth model explaining the dynamics of the spread of COVID-19 in Egypt. The model which is simple follows well-known premises in population dynamics. Our aim is to calculate an approximate estimate of the total number of infected persons during the course of the disease. The model predicted—to a high degree of correctness—the timing of the pandemic peak$$t_{{\text{m}}}$$ t m and the final epidemic size$$P$$ P ; the latter was foreseen by the model long before it was announced by the Egyptian authorities. The estimated values from the model were also found to match significantly with the nation reported data during the course of the disease. The period in which we applied the model was from the first of April 2020 until the beginning of October of the same year. By the time the manuscript was returned for revision, the second wave swept through Egypt and the authors felt obliged to renew their study. Finally, a comparison is made with the SIR model showing that ours is much simpler; yet leading to the same results.

scholarly journals Intergrating the Diversity Characteristics to Design a Quantitative Landscape Regionalization Framework: Case Study of Van Chan District, Yen Bai Province

2020 ◽  
Vol 36 (3) ◽  
Author(s):  
Pham Minh Tam ◽  
Pham Hoang Hai ◽  
Nguyen Cao Huan ◽  
Pham Thu Thuy
Keyword(s):  
Land Use ◽  
Natural Resource ◽  
Landscape Metrics ◽  
Resource Planning ◽  
Diversity Indices ◽  
Uncertainty Reduction ◽  
Driving Factor ◽  
Landscape Unit ◽  
Natural Resource Planning

Landscape regionalization plays an important role in delineating the heterogeneous characteristics of territory, and provide the spatial fundamental data for natural resource planning and environmental protection activities. The integrating of the diversity indices (landscape metrics) is expressed the change of landscape structure by the richness and evenness of land-use objectives. In this study, a quantitative landscape regionalization framework is designed from 03 group (attribute factor, driving factor, and diversity factor) of basic landscape unit. By using k-means clustering, the study is classified into 06 sub-regions of 68 watersheds in the administration boundary of Van Chan district, Yen Bai province. With the comparison of region numbers in statistical and practical dimensions, the optimal results are edited and determined 15 sub-regions for uncertainty reduction of landscape regionalization.

scholarly journals Uncertainty Reduction Theory in a New Work Environment: A Case of Teachers and School Principals Mutation in Cilandak District

Humaniora ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 97
Author(s):  
Dina Sekar Vusparatih
Keyword(s):  
Interpersonal Communication ◽  
School Principals ◽  
Uncertainty Reduction ◽  
Reduction Theory ◽  
Case Study Method ◽  
Uncertainty Reduction Theory ◽  
New School ◽  
Interactive Strategies ◽  
Almost All

This researched aimed to show the mutation in the education field in Indonesia because every teacher and principal would have at least once in his/her carrier. Through a qualitative approach and a case study method in Cilandak subdistrict, this research tried to analyze how educators underwent mutations using strategies from Uncertainty Reduction Theory (URT). By using interview and observation techniques, it is found that almost all educators use passive, active, and interactive strategies in gathering various information about the new school that is intended before carrying out the transfer. A forum of teachers or principals and joining community educator groups can be a bridge and media in carrying out this strategy so that it can reduce uncertainties in facing new environments and avoid conflicts that may occur due to ignorance and other threats. To get a certain situation using URT, it needs good competence in interpersonal communication as well.

scholarly journals Conventional Lathe Remanufacturing into CNC Machine Tool: Uncertainty Modeling Approach

2020 ◽  
pp. 97-133
Author(s):  
Ziyad Tariq Abdullah
Keyword(s):  
Decision Making ◽  
Machine Tool ◽  
Uncertainty Modeling ◽  
Uncertainty Reduction ◽  
Advanced Technology ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Cnc Lathe ◽  
Optimum Solution

Aims: Uncertainty modeling to study possibility of proposing several remanufacturing alternatives of conventional lathe into CNC machine tool. Study Design: Conventional lathe into CNC machine remanufacturing-upgrading experience is used to project the suitable literature comparatively to construct uncertainty modeling. Faults modes of conventional lathe are studied to propose different remanufacturing solution based on faults literature viewpoints in field of lathe remanufacturing-upgrading, which are reviewed and modified to accommodate new changes that can accompany the current case study. Place and Duration of Study: Middle Technical University, Institute of Technology-Baghdad, Mechanical Techniques Department, between January 2020 and July 2020. Methodology: Decision making for selection of remanufactured alternatives and remanufacturing portfolio alternatives in field of lathe remanufacturing are reviewed. Experience in field of lathe remanufacturing is exploited to remodeling of existence models to optimize a remanufactured lathe into CNC machine as a case study. Methodology can be concluded into:- Literature survey to find two paths of: Faults and their statutes study. Remanufacturing portfolio study. Literature re-presentation and modeling. Literature results graphical modeling. Mathematical modeling of remanufacturability. Restoration alternative modeling Modeling of uncertainty. Results: Emerged technology aided conventional lathe into CNC lathe remanufacturing alternative exhibits good behavior of criteria toward optimization. While Advanced technology aided conventional lathe into CNC lathe remanufacturing alternative exhibits behavior to be of interesting ability to be a reservoir of developing potentials. Conventional technology aided conventional lathe remanufacturing alternative is of lower potentials to be developed into optimum solution. Conclusion: Remanufacturing-upgrading of conventional lathe into CNC machine in its mechanical part, it is merely traditional remanufacturing process of conventional lathe. Developing potentials can include that gearbox can be eliminated due to use of motorized axis, feed rod and lead screws, in both forward and transvers directions, can be replaced with motorized ball screws. Also tool post can be replaced with automatic tool changer while dovetail guide ways and saddles can be reused. Comparative literature based analysis and experience based analysis for uncertainty reduction can substitute the leak of relevant data acquisition for decision-making in field of remanufacturing. Uncertainty reduction modeling can enable simplify certain difficulties, the calculation of some criteria and adopting of simplified analysis methods so that theoretic and practical gap can be directed towards certain actual conditions to reach the optimum solution.

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