scholarly journals Slope Superficial Displacement Monitoring by Small Baseline SAR Interferometry Using Data from L-band ALOS PALSAR and X-band TerraSAR: A Case Study of Hong Kong, China

2014 ◽  
Vol 6 (2) ◽  
pp. 1564-1586 ◽  
Author(s):  
Fulong Chen ◽  
Hui Lin ◽  
Xianzhi Hu
Keyword(s):  
Hong Kong ◽  
Sar Interferometry ◽  
Displacement Monitoring ◽  
Alos Palsar ◽  
X Band ◽  
L Band ◽  
Small Baseline ◽  
Using Data

Language Teaching during a Pandemic: A Case Study of Zoom Use by a Secondary ESL Teacher in Hong Kong

RELC Journal ◽  
2021 ◽  
pp. 003368822098178
Author(s):  
Anisa Cheung
Keyword(s):  
Professional Development ◽  
Hong Kong ◽  
Technology Integration ◽  
Online Teaching ◽  
Pedagogical Beliefs ◽  
Structured Interviews ◽  
Online Mode ◽  
Using Data ◽  
Synchronous Online

This article reports a case study of an English as a Second Language (ESL) teacher in Hong Kong who conducted lessons via Zoom during the COVID-19 pandemic. The study focused on the factors influencing her technology integration in synchronous online teaching mode. Using data from classroom recordings, stimulated-recall and semi-structured interviews, this study uncovered how Zoom functioned as a substitute for face-to-face lessons. The findings revealed that although there were fewer interactions between the teacher and her students, teaching in synchronous online mode provided the teacher with opportunities to utilize certain online features to augment methods of checking student understanding. The study identified the teacher’s pedagogical beliefs, the context and professional development as factors that influenced the level of technology integration in her Zoom classes. The study concludes that embracing process-oriented pedagogies may be necessary for a higher level of technology integration among ESL teachers who have adequate professional development opportunities and school support.

scholarly journals Time-Series InSAR Analysis of the Small Baseline Subset to Estimate Surface Deformation at Mt. Bromo Indonesia

Teknik ◽  
2019 ◽  
Vol 39 (2) ◽  
pp. 126
Author(s):  
Arliandy Pratama Arbad ◽  
Wataru Takeuchi ◽  
Yosuke Aoki ◽  
Achmad Ardy ◽  
Mutiara Jamilah
Keyword(s):  
Time Series ◽  
Surface Deformation ◽  
Sar Interferometry ◽  
Alos Palsar ◽  
Small Baseline Subset ◽  
Sar Data ◽  
Small Baseline

Penginderaan jauh kini memainkan peranan penting dalam pengamatan perilaku gunung api. Penelitian ini bertujuan untuk mengamati deformasi permukaan Gunung Bromo, yang terletak di Jawa bagian Timur, Indonesia, yang masuk dalam rangkaian sistem volkanik di Taman Nasional Bukit Tengger Semeru (TNBTS). Penggunaan algoritma SAR Interferometry (InSAR) yang disebut sebagai pendekatan Small Baseline Subset (SBAS) memungkinkan perancangan peta kecepatan deformasi rata-rata dan and peta time series displacement di wilayah kajian. Teknik SBAS yang biasa menghasilkan rangkaian observasi tahap interferometrik. Ini tercatat sebagai kombinasi linear dari nilai fase SAR  scene untuk setiap pixel secara tersendiri. Analisis yang dilakukan terutama berdasarkan 22 data SAR data yang diperoleh melalui sensor ALOS/PALSAR selama kurun waktu 2007–2011. Beberapa penelitian menunjukkan bahwa kemampuan analisis InSAR dalam menyelidiki siklus gunung api, terutama Gunung Bromo yang memiliki karakteristik erupsi stratovolcano dalam satu hingga lima tahun. Analisis hasil memperlihatkan adanya kemajuan dari kajian sebelumnya akan InSAR wilayah tersebut, yang lebih fokus  kepada deformasi yang berpengaruh kepada kaldera. Hal ini menunjukkan bahwa penelitian ini bisa diimplementasikan pada manajemen risiko atau manajemen infrastruktur

TIME-SERIES SAR INTERFEROMETRY ANALYSIS OF SURFACE DEFORMATION AT MT. BROMO INDONESIA

2019 ◽  
Vol 3 ◽  
pp. 771
Author(s):  
Arliandy Pratama Arbad ◽  
Wataru Takeuchi ◽  
Yosuke Yosuke ◽  
Mutiara Jamilah ◽  
Achmad Ardy
Keyword(s):  
Time Series ◽  
Surface Deformation ◽  
Sar Interferometry ◽  
Time Interval ◽  
Infrastructure Management ◽  
Alos Palsar ◽  
Volcanic System ◽  
Deformation Velocity ◽  
Small Baseline Subset ◽  
Small Baseline

One of the most active volcanoes in Indonesia is Mt. Bromo, volcanic activities at Mt. Bromo has been recorded in 1775. We observe the surface deformation of the Mt. Bromo which located at eastern Java Indonesia area that includes neighborhood volcanic system on TNBTS (Taman Nasional Bukit Tengger Semeru). Recently, remote sensing has played as an important role to observe volcano behavior. We apply the SAR Interferometry (InSAR) algorithm referred to as Small Baseline Subset (SBAS) approach that allows us to generate mean deformation velocity maps and displacement time series for the studied area. The common SBAS technique, the set of interferometric phase observations writes as a linear combination of individual SAR scene phase values for each pixel independently. Particularly, the proposed analysis is based on 22 SAR data acquired by the ALOS/PALSAR sensors during the 2007–2017 time interval. A fewer studies have been able to show capability of InSAR analysis for investigating cycle of volcano especially of Mt. Bromo which characterized eruption stratovolcano in ranging one to five years. The results expected in this work represent an advancement of previous InSAR studies of the area that are mostly focused on the deformation affecting the caldera. According to the result, we expected this study could implement on risk management or infrastructure management.

Scattering-Mechanism-Based Investigation of Optimal Combinations of Polarimetric SAR Frequency Bands for Land Cover Classification

2019 ◽  
Vol 85 (11) ◽  
pp. 799-813
Author(s):  
Zhixin Qi ◽  
Anthony Gar-On Yeh ◽  
Xia Li
Keyword(s):  
Land Cover ◽  
Land Cover Classification ◽  
Support Vector ◽  
Frequency Variation ◽  
Polarimetric Sar ◽  
Alos Palsar ◽  
Frequency Bands ◽  
Land Cover Types ◽  
X Band ◽  
L Band

Aiming at steering the selection of optimal combinations of polarimetric SAR (PolSAR) frequency bands for different land cover classification schemes, this study investigates the land cover classification capabilities of all the possible combinations of L-band ALOS PALSAR fully PolSAR data, C-band RADARSAT-2 fully PolSAR data, and X-band TerraSAR-X HH SAR data. A method that integrates polarimetric decomposition, object-based image analysis, decision tree algorithms, and support vector machines is used for the classification. Polarimetric decomposition theorems are used to interpret the scattering mechanisms at the different frequency bands to reveal the effect mechanisms of PolSAR frequency variation on the classification capability. This study finds that (1) X-band HH SAR is not necessary for classifying the land cover types involved in this study when C- or L-band fully PolSAR are used; (2) C-band fully PolSAR alone is adequate for classifying primitive land cover types, namely, water, bare land, vegetation, and built-up areas; and (3) L-band fully PolSAR alone is adequate for distinguishing between various vegetation types, such as crops, banana trees, and forests.

scholarly journals Earth and Rock-Filled Dam Monitoring by High-Resolution X-Band Interferometry: Gongming Dam Case Study

2019 ◽  
Vol 11 (3) ◽  
pp. 246 ◽  
Author(s):  
Tao Li ◽  
Mahdi Motagh ◽  
Mingzhou Wang ◽  
Wei Zhang ◽  
Chunlong Gong ◽  
...  
Keyword(s):  
High Resolution ◽  
Incidence Angle ◽  
Sar Interferometry ◽  
Surface Moisture ◽  
X Band ◽  
Shrinking Process ◽  
Data Fusing ◽  
Dam Monitoring ◽  
Settlement Analysis

Middle-sized earth- and rock-filled dams with clay cores continue to settle by approximately 0.5–1.5% of their height for approximately 1–3 years after their construction phase. This paper investigates the use of high-resolution spaceborne Synthetic aperture Radar (SAR) interferometry to monitor this settlement process, with the case of the Gongming dam in China. The varieties of slope foreshortening and stretching in the radar coordinates are attributed to the radar’s local incidence angle and the dam’s slope heading, which are analysed in detail. Focusing on the embankment slope settlement analysis, the equations for calculating foreshortening and the line-of-sight deformation decomposition are derived in detail for the adjustment and data fusing. The scattering characteristics of different materials on the dam surface are analysed, including the grass slope, concrete slope, top road (crest), top wall, step, and ditch. According to the analysis of the precipitation data from a local meteorological station, the coherence losses on the slopes are mainly caused by surface moisture. Both the TerraSAR-X Spotlight (TSX-SL) data and the COSMO-SkyMed Strip Mode (CSK-SM) data are analysed by the stacking method to assess the slopes’ deformations. The TSX-SL data results show the highest rate of settlement as 2 cm/yr on the top of the dam slope, consistent with the clay core shrinking process. The CSK-SM data show a similar trend in the lower part of the dam slope but underestimate the deformation in the upper part of the slope.

scholarly journals Surface deformation detected by the space-observed small baseline SAR interferometry over permafrost environment in Tibet Plateau, China

2012 ◽  
Vol 6 (5) ◽  
pp. 4071-4099 ◽  
Author(s):  
F. Chen ◽  
H. Lin
Keyword(s):  
Climate Change ◽  
Active Layer ◽  
Surface Deformation ◽  
Anthropogenic Activities ◽  
Sar Interferometry ◽  
Tibet Plateau ◽  
Alos Palsar ◽  
Permafrost Environment ◽  
Water Level Variations ◽  
Small Baseline

Abstract. The evolution of permafrost and the active layer is highly related to climate change because of its feedback effects involving water and carbon storage. In this study, we firstly examined the relationship of regional water balance, geomorphological process and anthropogenic activities by means of Small Baseline Synthetic Aperture Radar Interferometry (SB-InSAR) to monitor the surface movements overlaid on the permafrost of Tibet Plateau (TP), China, using 3.5-yr observation span of L-band ALOS PALSAR data (June, 2007 to December, 2010). The estimated displacements (primarily in the range of −30 mm yr−1 to 30 mm yr−1) and time-series implied evolutions of the active layer and permafrost beneath. The motion trend along slopes was complicated, and thus interdisciplinary interpretations were required. Water level variations of inland lakes were then detected, although further investigations were required for validation. Anthropogenic influences on this frail permafrost environment were significant, proved by the remarkable surface settlement along the embankment of Qinghai-Tibet Railway. Consequently, it is crucial and necessary to monitor this arid and cold plateau owing to the combination of climate change, geo-hazards prediction as well as the regional sustainable development.

Sign in / Sign up

Export Citation Format

Share Document