scholarly journals Exploration of data space through trans‐dimensional sampling: A case study of 4D seismics

2021 ◽  
Author(s):  
Nicola Piana Agostinetti ◽  
Maria Kotsi ◽  
Alison Malcolm
Keyword(s):  
Data Space

scholarly journals Minimum/maximum autocorrelation factors applied to grade estimation

2014 ◽  
Vol 67 (2) ◽  
pp. 209-214
Author(s):  
Camilla Zacché da Silva ◽  
João Felipe Coimbra Leite Costa
Keyword(s):  
Original Data ◽  
Mineral Deposits ◽  
Correlated Variables ◽  
Grade Estimation ◽  
Data Space ◽  
Geostatistical Approach ◽  
Covariance Modeling ◽  
Estimation Problems ◽  
Direct Covariance

It is frequent to face estimation problems when dealing with mineral deposits involving multiple correlated variables. The resulting model is expected to reproduce data correlation. However, is not guaranteed that the correlation observed among data will be reproduced by the model, if the variables are estimated independently, and this correlation is not explicitly taken into account. The adequate geostatistical approach to address this estimation problem is co-kriging which requires cross and direct covariance modeling of all variables, satisfying the LMC. An alternative is to decorrelate the variables and estimate each independently, using for instance, the minimum/maximum autocorrelation factors (MAF) approach, which uses a linear transformation on the correlated variables, transforming them to a new uncorrelated set. The transformed data can be estimated through kriging. Afterwards, the estimates are back-transformed to the original data space. The methodology is illustrated in a case study where three correlated variables are estimated using the MAF method combined with kriging and through co-kriging, used as a benchmark. The results show less than a 2% deviation between both methodologies.

scholarly journals Exploration of the data space via trans-dimensional sampling: the case study of seismic double difference data

2021 ◽  
Author(s):  
Nicola Piana Agostinetti ◽  
Giulia Sgattoni
Keyword(s):  
Seismic Data ◽  
Time Window ◽  
Time Windows ◽  
Correlation Coefficients ◽  
Double Difference ◽  
Seismicity Rate ◽  
Data Space ◽  
Double Differences ◽  
Time Invariant

Abstract. Double differences (DD) seismic data are widely used to define elasticity distribution in the Earth's interior, and its variation in time. DD data are often pre-processed from earthquakes recordings through expert-opinion, where couples of earthquakes are selected based on some user-defined criteria, and DD data are computed from the selected couples. We develop a novel methodology for preparing DD seismic data based on a trans-dimensional algorithm, without imposing pre-defined criteria on the selection of couples of events. We apply it to a seismic database recorded on the flank of Katla volcano (Iceland), where elasticity variations in time has been indicated. Our approach quantitatively defines the presence of changepoints that separate the seismic events in time-windows. Within each time-window, the DD data are consistent with the hypothesis of time-invariant elasticity in the subsurface, and DD data can be safely used in subsequent analysis. Due to the parsimonious behavior of the trans-dimensional algorithm, only changepoints supported by the data are retrieved. Our results indicate that: (a) retrieved changepoints are consistent with first-order variations in the data (i.e. most striking changes in the DD data are correctly reproduced in the changepoint distribution in time); (b) changepoint locations in time do correlate neither with changes in seismicity rate, nor with changes in waveforms similarity (measured through the cross-correlation coefficients); and (c) noteworthy, the changepoint distribution in time seems to be insensitive to variations in the seismic network geometry during the experiment. Our results proofs that trans-dimensional algorithms can be positively applied to pre-processing of geophysical data before the application of standard routines (i.e. before using them to solve standard geophysical inverse problems) in the so called exploration of the data space.

scholarly journals PRIMARY STUDENTS’ MATHEMATICAL LITERACY: A CASE STUDY

2020 ◽  
Vol 9 (1) ◽  
pp. 49
Author(s):  
Rooselyna Ekawati ◽  
Susanti Susanti ◽  
Jian-Cheng Chen
Keyword(s):  
Cluster Analysis ◽  
Opportunity To Learn ◽  
Social Background ◽  
Sixth Graders ◽  
Primary Students ◽  
Mathematical Literacy ◽  
Data Space ◽  
Analysis Methodology ◽  
Mathematics Literacy

This paper analyses Indonesian primary students’ Mathematical literacy in solving PISA like problems. The instruments were administered to 254 sixth graders from five different regions in Surabaya, Indonesia with various social background. There were three contents (quantity, Uncertainty and data, space and shape) and three level problems (High, Medium and Easy) used to develop Mathematics Literacy Test (MLT). Three students’ categories (Good, Middle and Low) were established by cluster analysis methodology. The most students’ challenge on MLT was space and shape as well as uncertainty and data’s content problem. The description of profile of primary students’ mathematical literacy related to MLT are worthy to suggest the design of learning lines for primary students to have more opportunity to learn and solve Mathematics literacy problem.

scholarly journals Exploration of data space through trans-dimensional sampling: A case study of 4D seismics

2021 ◽  
Author(s):  
Nicola Piana Agostinetti ◽  
Maria Kotsi ◽  
Alison Malcolm
Keyword(s):  
Data Space

The Genesis and Internal Dynamics of El Salvador's People's Revolutionary Army, 1970–1976

2014 ◽  
Vol 38 (01) ◽  
pp. 102-129
Author(s):  
ALBERTO MARTÍN ÁLVAREZ ◽  
EUDALD CORTINA ORERO
Keyword(s):  
Latin America ◽  
El Salvador ◽  
Early Years ◽  
Left Wing ◽  
Internal Dynamics ◽  
Internal Coherence ◽  
The 1960S

AbstractUsing interviews with former militants and previously unpublished documents, this article traces the genesis and internal dynamics of the Ejército Revolucionario del Pueblo (People's Revolutionary Army, ERP) in El Salvador during the early years of its existence (1970–6). This period was marked by the inability of the ERP to maintain internal coherence or any consensus on revolutionary strategy, which led to a series of splits and internal fights over control of the organisation. The evidence marshalled in this case study sheds new light on the origins of the armed Salvadorean Left and thus contributes to a wider understanding of the processes of formation and internal dynamics of armed left-wing groups that emerged from the 1960s onwards in Latin America.

Culture and the plasticity of perception

2020 ◽  
Vol 43 ◽  
Author(s):  
Michael Lifshitz ◽  
T. M. Luhrmann
Keyword(s):  
Cultural Context ◽  
Sensory Experience ◽  
Cultural Learning ◽  
The World

Abstract Culture shapes our basic sensory experience of the world. This is particularly striking in the study of religion and psychosis, where we and others have shown that cultural context determines both the structure and content of hallucination-like events. The cultural shaping of hallucinations may provide a rich case-study for linking cultural learning with emerging prediction-based models of perception.

Dual systems for all: Higher-order, role-based relational reasoning as a uniquely derived feature of human cognition

2019 ◽  
Vol 42 ◽  
Author(s):  
Daniel J. Povinelli ◽  
Gabrielle C. Glorioso ◽  
Shannon L. Kuznar ◽  
Mateja Pavlic
Keyword(s):  
Temporal Reasoning ◽  
Higher Order ◽  
Important Case ◽  
Human Cognition ◽  
Relational Reasoning ◽  
Dual Systems ◽  
First Order ◽  
Reasoning System ◽  
Role Based

Abstract Hoerl and McCormack demonstrate that although animals possess a sophisticated temporal updating system, there is no evidence that they also possess a temporal reasoning system. This important case study is directly related to the broader claim that although animals are manifestly capable of first-order (perceptually-based) relational reasoning, they lack the capacity for higher-order, role-based relational reasoning. We argue this distinction applies to all domains of cognition.

Sociocultural memory development research drives new directions in gadgetry science

2019 ◽  
Vol 42 ◽  
Author(s):  
Penny Van Bergen ◽  
John Sutton
Keyword(s):  
Episodic Memory ◽  
Autobiographical Memory ◽  
Developmental Psychology ◽  
Cross Cultural ◽  
Memory Development ◽  
Development Research ◽  
Cultural Research ◽  
New Directions ◽  
Cross Cultural Research

Abstract Sociocultural developmental psychology can drive new directions in gadgetry science. We use autobiographical memory, a compound capacity incorporating episodic memory, as a case study. Autobiographical memory emerges late in development, supported by interactions with parents. Intervention research highlights the causal influence of these interactions, whereas cross-cultural research demonstrates culturally determined diversity. Different patterns of inheritance are discussed.

Construction of plastic contact deformation maps on ceramics: a case study on aluminum nitride

1996 ◽  
Vol 54 ◽  
pp. 636-637
Author(s):  
D. L. Callahan
Keyword(s):  
Plastic Deformation ◽  
Aluminum Nitride ◽  
Mechanical Response ◽  
Three Dimensional ◽  
Bright Field Image ◽  
Perfectly Plastic ◽  
Contrast Analysis ◽  
Deformation Patterns

Modern polishing, precision machining and microindentation techniques allow the processing and mechanical characterization of ceramics at nanometric scales and within entirely plastic deformation regimes. The mechanical response of most ceramics to such highly constrained contact is not predictable from macroscopic properties and the microstructural deformation patterns have proven difficult to characterize by the application of any individual technique. In this study, TEM techniques of contrast analysis and CBED are combined with stereographic analysis to construct a three-dimensional microstructure deformation map of the surface of a perfectly plastic microindentation on macroscopically brittle aluminum nitride.The bright field image in Figure 1 shows a lg Vickers microindentation contained within a single AlN grain far from any boundaries. High densities of dislocations are evident, particularly near facet edges but are not individually resolvable. The prominent bend contours also indicate the severity of plastic deformation. Figure 2 is a selected area diffraction pattern covering the entire indentation area.

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