sequential simulation
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2021 ◽  
Vol 936 (1) ◽  
pp. 012042
Author(s):  
Nurrohmat Widjajanti ◽  
Bayu Nata ◽  
Parseno

Abstract The Opak Fault is an active fault that can potentially cause earthquakes in Yogyakarta. Periodic monitoring of the Opak Fault activity was previously used more GNSS observation data from the measurement campaign by the Geodesi Geometri dan Geodesi Fisis (GGGF) Laboratory Team, Geodetic Engineering Department, Faculty of Engineering, Universitas Gadjah Mada. However, there are several CORS BIG stations located in Yogyakarta. The CORS BIG data is used to increase the precision of the Opak Fault monitoring station. Therefore, the addition of the CORS is evaluated to obtain a displacement in the monitoring station. The computation of the displacement velocity value of the Opak Fault monitoring station has been done before using the Linear Least Square Collocation and grid search methods. The other method, namely the kriging method, needs to be evaluated for producing a more precise displacement velocity value. The research data includes GNSS campaign and CORS BIG data for six years, 2013 to 2020. The CORS stations around DIY are JOGS and CBTL. The GNNS data were processed to determine the solution for the daily coordinate, displacement, and standard deviation values for each Opak Fault monitoring station. The displacement velocity value is generated by the Linear Least Square method then reduced from the influence of the Sunda Block. The velocity value is used in the strain value estimation around the Opak Fault area at each station using the kriging method combined with the gaussian sequential simulation technique. The estimated displacement velocities are examined for statistical significance compared to the research of Adam (2019) and Pinasti (2019). This research generates the value of the displacement velocity in the east and north components of 12.39 to 30.99 mm/year and 1.96 to -14.11 mm/year, respectively. The displacement direction of all monitoring stations is dominant to the southeast. The Sunda Block reduced the displacement velocity. The east and north components are -2.32 to 2.28 mm/year and -0.52 to 4.2 mm/year, respectively. The displacement direction is towards the northwest. The strain estimation using the kriging method combined with the gaussian sequential simulation technique obtained an average strain value of 0.05 microstrain/year. The result of the data processing at each station has different arrow lengths, meaning that each location has a different strain value.


Author(s):  
Alan Troncoso ◽  
Xavier Freulon ◽  
Christian Lantuéjoul

2021 ◽  
Vol 108 (Supplement_2) ◽  
Author(s):  
J Ashcroft ◽  
N Havers ◽  
A Seebacher-Tomas ◽  
E Plesci ◽  
S Goh ◽  
...  

Abstract Introduction Covid-19 necessitated the early graduation of medical students to join the healthcare workforce as Foundation Interim Year 1 (FiY1) doctors. A sequential simulation session was implemented to improve and assess FiY1 preparedness towards approaching deteriorating patients. Method 12 FiY1 doctors participated in the session containing three sequential major stations: complex new admission, ward-based management, and acute deterioration. Participants interpreted investigations, performed examinations, created management plans, and escalated using a pager. Results There was a significant improvement in preparedness for giving treatment (median(IQR): pre-simulation 3(3-4) vs. post-simulation 4(4-4.75); p = 0.04) and paperwork (2(2-3.75) vs. 4(3.25-4.75); p = 0.03). Following four weeks of FiY1 participants demonstrated significant improvement in preparedness for giving treatment (median(IQR): pre-simulation 3(3-4) vs. post-FiY1 4.5(4-5); p = 0.01), communication and teamworking (4(3.25-4.75) vs. 5(5-5.75); p = 0.01), and paperwork (2(2-3.75) vs. 5(5-5); p = 0.01). The FiY1 programme improved integration within teams and facilitated training whilst medical school placements left participants feeling apprehensive and unprepared to practice. Conclusions This session provided an engaging method of increasing preparedness towards common challenges new physicians face. This study suggests future senior medical student apprenticeships should give the same investment, opportunities, and responsibilities as that of the FiY1 programme.


Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 368
Author(s):  
Cristina Alegria ◽  
Natália Roque ◽  
Teresa Albuquerque ◽  
Paulo Fernandez ◽  
Maria Margarida Ribeiro

Research Highlights: Modelling species’ distribution and productivity is key to support integrated landscape planning, species’ afforestation, and sustainable forest management. Background and Objectives: Maritime pine (Pinus pinaster Aiton) forests in Portugal were lately affected by wildfires and measures to overcome this situation are needed. The aims of this study were: (1) to model species’ spatial distribution and productivity using a machine learning (ML) regression approach to produce current species’ distribution and productivity maps; (2) to model the species’ spatial productivity using a stochastic sequential simulation approach to produce the species’ current productivity map; (3) to produce the species’ potential distribution map, by using a ML classification approach to define species’ ecological envelope thresholds; and (4) to identify present and future key factors for the species’ afforestation and management. Materials and Methods: Spatial land cover/land use data, inventory, and environmental data (climate, topography, and soil) were used in a coupled ML regression and stochastic sequential simulation approaches to model species’ current and potential distributions and productivity. Results: Maritime pine spatial distribution modelling by the ML approach provided 69% fitting efficiency, while species productivity modelling achieved only 43%. The species’ potential area covered 60% of the country’s area, where 78% of the species’ forest inventory plots (1995) were found. The change in the Maritime pine stands’ age structure observed in the last decades is causing the species’ recovery by natural regeneration to be at risk. Conclusions: The maps produced allow for best site identification for species afforestation, wood production regulation support, landscape planning considering species’ diversity, and fire hazard mitigation. These maps were obtained by modelling using environmental covariates, such as climate attributes, so their projection in future climate change scenarios can be performed.


2021 ◽  
Vol 8 (1) ◽  
pp. e137-e141
Author(s):  
Noah Havers ◽  
Alvaro Seebacher-Tomas ◽  
James Ashcroft

Author(s):  
Lingqing Yao ◽  
Roussos Dimitrakopoulos ◽  
Michel Gamache

AbstractA training image free, high-order sequential simulation method is proposed herein, which is based on the efficient inference of high-order spatial statistics from the available sample data. A statistical learning framework in kernel space is adopted to develop the proposed simulation method. Specifically, a new concept of aggregated kernel statistics is proposed to enable sparse data learning. The conditioning data in the proposed high-order sequential simulation method appear as data events corresponding to the attribute values associated with the so-called spatial templates of various geometric configurations. The replicates of the data events act as the training data in the learning framework for inference of the conditional probability distribution and generation of simulated values. These replicates are mapped into spatial Legendre moment kernel spaces, and the kernel statistics are computed thereafter, encapsulating the high-order spatial statistics from the available data. To utilize the incomplete information from the replicates, which partially match the spatial template of a given data event, the aggregated kernel statistics combine the ensemble of the elements in different kernel subspaces for statistical inference, embedding the high-order spatial statistics of the replicates associated with various spatial templates into the same kernel subspace. The aggregated kernel statistics are incorporated into a learning algorithm to obtain the target probability distribution in the underlying random field, while preserving in the simulations the high-order spatial statistics from the available data. The proposed method is tested using a synthetic dataset, showing the reproduction of the high-order spatial statistics of the sample data. The comparison with the corresponding high-order simulation method using TIs emphasizes the generalization capacity of the proposed method for sparse data learning.


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