A geodetic approach to gravity data reduction for geophysics

1997 ◽  
Vol 23 (10) ◽  
pp. 1063-1070 ◽  
Author(s):  
W.E. Featherstone ◽  
M.C. Dentith
Keyword(s):  
Data Reduction ◽  
Gravity Data

Airborne gravity measurements over mountainous areas by using a LaCoste & Romberg air‐sea gravity meter

Geophysics ◽  
2002 ◽  
Vol 67 (3) ◽  
pp. 807-816 ◽  
Author(s):  
Jérôme Verdun ◽  
Roger Bayer ◽  
Emile E. Klingelé ◽  
Marc Cocard ◽  
Alain Geiger ◽  
...  
Keyword(s):  
Data Reduction ◽  
Classical Method ◽  
Gravity Data ◽  
Airborne Gravity ◽  
Mountainous Area ◽  
Vertical Acceleration ◽  
Mountainous Areas ◽  
Free Air ◽  
Gravity Measurements ◽  
Free Air Anomaly

This paper introduces a new approach to airborne gravity data reduction well‐suited for surveys flown at high altitude with respect to gravity sources (mountainous areas). Classical technique is reviewed and illustrated in taking advantage of airborne gravity measurements performed over the western French Alps by using a LaCoste & Romberg air‐sea gravity meter. The part of nongravitational vertical accelerations correlated with gravity meter measurements are investigated with the help of coherence spectra. Beam velocity has proved to be strikingly correlated with vertical acceleration of the aircraft. This finding is theoretically argued by solving the equation of the gravimetric system (gravity meter and stabilized platform). The transfer function of the system is derived, and a new formulation of airborne gravity data reduction, which takes care of the sensitive response of spring tension to observable gravity field wavelengths, is given. The resulting gravity signal exhibits a residual noise caused by electronic devices and short‐wavelength Eötvös effects. The use of dedicated exponential filters gives us a way to eliminate these high‐frequency effects. Examples of the resulting free‐air anomaly at 5100‐m altitude along one particular profile are given and compared with free‐air anomaly deduced from the classical method for processing airborne gravity data, and with upward‐continued ground gravity data. The well‐known trade‐off between accuracy and resolution is discussed in the context of a mountainous area.

scholarly journals Modeling Folding Zone in Kedungsari Compassionate Area Kulon Progo Yogyakarta with Gravity Method

2017 ◽  
Vol 1 ◽  
pp. 19-22
Author(s):  
Maya Luthfiya ◽  
Thaqibul Fikri Niyartama
Keyword(s):  
Data Reduction ◽  
Horizontal Plane ◽  
Gravity Data ◽  
Continuation Method ◽  
Bouguer Anomaly ◽  
Research Area ◽  
Quantitative Interpretation ◽  
Gravity Method ◽  
Local Anomaly ◽  
Andesitic Rock

This study aims to determine the condition of subsurface by doing interpretation quantitatively. Quantitative interpretation is done by modeling to determine the shape and boundary of the anomaly. The gravity data reduction is done up to Complete Bouguer Anomaly (CBA) value is obtained. The complete Bouguer anomaly is brought to horizontal plane reduction and separation of local and regional anomalies using the upward continuation method. 2.5 modelling has been made from local anomaly data to illustrate the subsurface condition of the research area more clearly. The result shows R1 density value of 2.55 g / m3 which is a limestone and R2 2,8902 g/m3 which is andesitic rock. The position of the anticline axis is at coordinates 49 S 9128700 N 409844.9 E, while the syncline axis is at coordinates 9129037 N 408694,1 E.

GRAVITY data reduction software

2014 ◽  
Author(s):  
V. Lapeyrere ◽  
P. Kervella ◽  
S. Lacour ◽  
N. Azouaoui ◽  
C. E. Garcia-Dabo ◽  
...  
Keyword(s):  
Data Reduction ◽  
Gravity Data

scholarly journals Increasing the achievable contrast of infrared interferometry with an error correlation model

2020 ◽  
Vol 644 ◽  
pp. A110
Author(s):  
J. Kammerer ◽  
A. Mérand ◽  
M. J. Ireland ◽  
S. Lacour
Keyword(s):  
Data Reduction ◽  
Gravity Data ◽  
Model Fitting ◽  
Detection Limits ◽  
Empirical Models ◽  
Correlated Noise ◽  
Strongly Correlated ◽  
Analysis Process ◽  
Very Large Telescope ◽  
Infrared Interferometry

Context. Interferometric observables are strongly correlated, yet it is common practice to ignore these correlations in the data analysis process. Aims. We develop an empirical model for the correlations present in Very Large Telescope Interferometer GRAVITY data and show that properly accounting for them yields fainter detection limits and increases the reliability of potential detections. Methods. We extracted the correlations of the (squared) visibility amplitudes and the closure phases directly from intermediate products of the GRAVITY data reduction pipeline and fitted our empirical models to them. Then, we performed model fitting and companion injection and recovery tests with both simulated and real GRAVITY data, which are affected by correlated noise, and compared the results when ignoring the correlations and when properly accounting for them with our empirical models. Results. When accounting for the correlations, the faint source detection limits improve by a factor of up to ∼2 at angular separations > 20 mas. For commonly used detection criteria based on χ2 statistics, this mostly results in claimed detections being more reliable. Conclusions. Ignoring the correlations present in interferometric data is a dangerous assumption which might lead to a large number of false detections. The commonly used detection criteria (e.g. in the model fitting pipeline CANDID) are only reliable when properly accounting for the correlations; furthermore, instrument teams should work on providing full covariance matrices instead of statistically independent error bars as part of the official data reduction pipelines.

The CLASSIC/CLIMB Data Reduction: The Math

2014 ◽  
Vol 69-70 ◽  
pp. 75-99
Author(s):  
T. ten Brummelaar
Keyword(s):  
Data Reduction

ELECTRONIC AREA DETECTOR DATA REDUCTION SYSTEM AT THE SRS

1986 ◽  
Vol 47 (C5) ◽  
pp. C5-109-C5-113
Author(s):  
J. W. CAMPBELL ◽  
D. CROFT ◽  
J. R. HELLIWELL ◽  
P. MACHIN ◽  
M. Z. PAPIZ ◽  
...  
Keyword(s):  
Data Reduction ◽  
Area Detector ◽  
Reduction System

INOVASI PEMBELAJARAN AKIDAH AKHLAK MENGGUNAKAN METODE ROLE PLAY DALAM MENINGKATKAN PRESTASI BELAJAR SISWA

2018 ◽  
Vol 2 (1) ◽  
pp. 52-63
Author(s):  
Ansori Ansori
Keyword(s):  
Data Reduction ◽  
Role Play ◽  
Learning Goals ◽  
New Paradigm ◽  
Learning Materials ◽  
Analysis Technique ◽  
Flexible Schedule ◽  
Using Data ◽  
Real Action

The use of various methods will greatly help students in achieving learning goals. As role play method is one way mastery of learning materials through the development of imagination and appreciation of students on learning materials. Data collection techniques in this study are observation, interviews, and documentation. To analyze the data in this research using data analysis technique of Miles and Huberman model that is data reduction (Data Reduction), data presentation (Data Display) and conclusion (Conclution Drawing / verification) The findings in this research is innovation of role play method can change paradigm to the new paradigm so that the role of the teacher is more as a facilitator, counselor, consultant, and comrade study Flexible schedule, open as needed Learning directed by students themselves Problem-based, project, real world, real action, and reflection Design and investigation. Computers as tools, and dynamic media presentations.

PENERAPAN PEMBELAJARAN BILINGUAL DI TINGKAT TK

2020 ◽  
Vol 11 (2) ◽  
pp. 97-111
Author(s):  
Siti Meutia Sari
Keyword(s):  
Data Reduction ◽  
Data Display

Fenomena penerapan pembelajaran bilingual pada anak usia dini sangat melekat dalam kehidupan sehari-hari sebagai antisipasi dari persaingan global. Anak yang diberikan pembelajaran bilingual sejak dini akan mampu bersaing dengan dunia luar dikarenakan bisa mempelajari kebudayaan luar yang notabene menggunakan bahasa Inggris sebagai bahasa dunia. Penelitian ini bertujuan untuk mendeskripsikan pembelajaran bilingual pada anak usia dini di TK Al Azhar, Medan. Penelitian ini menggunakan penelitian kualitatif deskriptif. Pemilihan subjek dilakukan sesuai dengan kebutuhan peneliti. Subjek penelitian ini adalah, Kepala Pengelola TK Al Azhar, guru kelas, perilaku peserta didik, dan orang tua. Metode yang digunakan untuk mengumpulkan data dalam penelitian ini adalah metode observasi,wawancara, serta dokumentasi. Dalam menganalisis data, peneliti menggunakanmodel Miles dan Huberman selama berada di lapangan. Aktivitas dalam analisis data meliputi data reduction, data display, dan conclusion drawing/verification. Hasil penelitian menunjukkan bahwa setiap anak mampu mengembangkan bahasa secara alami. Namun, pengembangan bahasa juga dipengaruhi oleh orang tua, lingkungan dan dunia pendidikan, terutama dalam pembelajaran dua bahasa (bilingual).Pembelajaran bilingual pada anak usia dini tidak boleh dengan paksaan dan harus dilakukan dengan kegiatan yang menyenangkan seperti, bernyanyi, bermain, danpembiasaan.

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