Monitoring land surface deformation using persistent scatterers interferometric synthetic aperture radar technique

Land subsidence is one of the major hazards occurring globally due to several reasons including natural and human activities. The effect of land subsidence depends on the extent and severity. The consequences of this hazard can be seen in many forms including damaged of infrastructures and loss of human lives. Although land subsidence is a global problem, but it is very common in urban and sub urban areas especially in rapidly developing countries. This problem needs to be monitored effectively. Several techniques such as land surveying, aerial photogrammetry and Global Positioning System (GPS) can be used to monitor or detect the subsidence effectively but these techniques are mostly expensive and time consuming especially for large area. In recent decades, Interferometric Synthetic Aperture Radar (InSAR) technique has been used widely for the monitoring of land subsidence successfully although this technique has several limitations due to temporal decorrelation, atmospheric effects and so on. However, the uncertainties related to InSAR technique have been reduced significantly with the recent Persistent Scatterers Interferometric Synthetic Aperture Radar (PSInSAR) technique which utilized a stack of interferograms generated from several radar images to estimate deformation by finding a bunch of stable points. This study investigates the surface deformation focusing on Kuala Lumpur, a rapidly growing city and Selangor using PSInSAR technique with a set of ALOS PALSAR images from 2007 to 2011. The research methodology consists of several steps of image processing that incudes i) generation of Differential Interferometric Synthetic Aperture Radar (DInSAR), ii) selection of Persistent Scatterers (PS) points, iii) removal of noise, iv) optimization of PS point selection, and v) generation of time series deformation map. However, special consideration was given to optimize the PS selection process using two master images. Results indicate a complete variation of mean line-of-sight (LOS) velocities over the study area. Stable areas (mean LOS=1.1 mm/year) were mostly found in the urban center of Kuala Lumpur, while medium rate of LOS (from 20 mm/year to 30 mm/year) was observed in the south west area in Kuala Langat and Sepang districts. The infrastructures in Kuala Lumpur are mostly stable except in Kuala Lumpur International Airport (KLIA) where a significant subsidence was detected (28.7 mm/year). Meanwhile, other parts of the study area such as Hulu Langat, Petaling Jaya and Klang districts show a very low and non-continuous movement (LOS < 20 mm/year), although comparatively higher subsidence rate (28 mm/year) was detected in the mining area. As conclusion, PSInSAR technique has a potential to monitor subsidence in urban and sub urban areas, but optimization of PS selection processing is necessary in order to reduce the noise and get better estimation accuracy

Preferences, perception of readiness and satisfaction towards online distance learning among undergraduates in Malaysia during COVID-19 pandemic

While there is abundance of studies regarding online distance learning (ODL) among university students, information regarding ODL among undergraduates in Malaysia is limited, more so during the Covid-19 pandemic. This was a cross-sectional online survey involving a total of 308 undergraduates from various universities in Malaysia aimed to evaluate undergraduates’ perception of readiness and satisfaction towards online distance learning, platform preferences, attitudes and motivations, barriers towards ODL and also factors contributing to these variables. Questionnaires that include Online Learning Readiness Scale (OLRS) and additional information regarding challenges faced by undergraduates and their satisfaction levels towards ODL were used in this survey. The results showed that the undergraduates preferred a combination of face-to-face and online learning (68.8%) rather than online learning alone (5.5%). Majority of the respondents preferred having synchronous classes as compared to asynchronous classes (37.7%) and they rated Google Meet as their most preferred platform for their classes. In addition, the undergraduates shown fairly goodperception and neutral satisfaction towards ODL. Factors such as ethnicity and the state where the undergraduates lived were found to more likely cause them to have poor satisfaction towards ODL. While, undergraduates who have handphones have a higher satisfaction level towards ODL. Several challenges were encountered throughout ODL with the most challenging was the unsupportive environment, which in turn causing the undergraduates to be distracted and losing focus during ODL. Our findings highlighted that majority undergraduates preferred a combination of face-to-face and online learning rather than online learning alone. These findings will be beneficial for educators in the planning for future teaching and learning methods. Future studies with a larger sample size are needed to evaluate the independent risk factors related to low motivations, perceptions and satisfaction among undergraduates using ODL

Monitoring of surface deformation due to earthquake using dinsar technique and palsar-2 data: a case study of the Gorkha Earthquake in Nepal, 2015

Once again Nepal was shocked by another earthquake with magnitude 7.8 Mw known as Gorkha Earthquake on April 25, 2015, after 81 years of the worst natural disaster that struck in 1934. Continued aftershocks occurred throughout Nepal within 15–20 minutes intervals, with one shock reaching a magnitude of 6.7 Mw on April 26, 2015. A major aftershock occurred on 12 May 2015, with 7.3 Mw. Geophysicists and other experts are warning for decades that Nepal is vulnerable to a deadly earthquake, particularly because of its geology as Nepal lies towards the southern limit of the diffuse collisional boundary where the Indian Plate under thrusts the Eurasian Plate, occupying the central sector of the Himalayan arc, nearly one-third of the 2,400 km (1,500 mi) long the Himalayas. Estimation of damaged especially surface deformation is an important part of the rebuilding planning process for natural disaster. Although field investigation is one of the best means for determination of surface deformation, this process is unable to explore a large area, especially in remote and inaccessible area. Remote Sensing technique, especially interferometric synthetic aperture radar (InSAR) is invaluable technique for assessment of surface deformation due to the natural disasters particularly earthquake. InSAR has the potential to provide important subsidence information over large areas because of its two-dimensional spatial coverage, competitive cost, data availability, and high vertical accuracy for remotely measuring the deformation of the ground and man-made structures from space. This technique can even achieve millimeter level accuracy using a technique called differential InSAR technique (DInSAR). However, the accuracy of this process depends on several factors such as availability of satellite data with optimal temporal and perpendicular baseline along with necessary ancillary data especially a high-resolution DEM (Digital Elevation Model). Therefore, this study is going to estimate the surface deformation in Nepal due to the Gorkha Earthquake using data from new L-band SAR sensor ALOS/PALSAR-2 which has been significantly improved in all aspects including resolution, observation band, and time lag compared to ALOS/PALSAR. Fine beam dual polarization (HH and HV) with 10 m resolution data that cover the earthquake areas were used to measure the surface deformation using the DInSAR technique. Results indicate that there was a large displacement of land surface due to the massive Gorkha Earthquake and subsequent aftershocks. However, the level of subsidence was varied from one place to another place probably due to the geological structure of the affected areas although most of the deformation was observed around the epicenters of the earthquake

Intention to use of fintech products and services among youngsters: The application of technology acceptance model (TAM)

Financial Technology or famous known as “Fintech” is an innovative financial service that emerged in tandem with the new technologies and advancement. The Islamic Banking and Finance researchers and students have recently started to explore the emerging industry of fintech with reference to Islamic Banking and Finance. Thus, the purpose of this study is to investigate the intention to use of fintech products and services among youngsters based on the application of Technology Acceptance Model (TAM). Quantitative method has been used which based on articles, journals and any other related materials. The data is collected from 357 youngsters using questionnaire through Google Form. The result of this study will show the measure level, examine the relationship and analyze the significant influence of perceived ease of use, perceived usefulness, and service trust on intention to use of Fintech’s products and service among youngsters. However, this study has potential limitations that occur during collection of the date which are limitation in the area of study, lacking time, and lacking fund and those limitations can be improved in the future

Printing and Curing of Conductive Ink Track on Fabric using Syringe Deposition System with DLP Projector and Hot Plate

Printing is a technique to transfer ink onto substrates to create pattern and syringe deposition system has shown some great potential in printing due to its ability to produce filamentary bead tracks which is important concerning conductivity and easily adopted on conformal surfaces which could not be realized by conventional technique. Fabrics with integrated electrical features able to create intelligent articles and may potentially open up new perspective areas of application in textile printing. However, the applicability of this technique on fabrics remains unknown which the ink used has to meet certain requirements including high electrical conductivity, resistance to oxidation, dry out without clogging, good adhesion with suitable viscosity and surface tension. Thus, there is a need to do this study which is to determine the feasibility of syringe deposition system to print a conductive ink tracks using silver epoxy-based conductive ink on fabric substrate via lycra material. This study is also aim to investigate the feasibility of using DLP projector with hot plate as another source of heat to be used in curing the ink tracks on fabric. The effect of printing and curing parameters to the characteristics and conductivity of the ink track is investigated. Several mechanical and electrical tests were also administered to determine the cure, hardness, adhesion and resistance level of the ink tracks. The results obtained were as expected which higher printing speed and lower deposition height used, a narrower and thinner ink tracks were produced. Sample with 4 mm/s of printing speed and deposition height of 1 mm resulted in dimension closer to the targeted dimension. The longer curing time and higher temperature used, a lower resistance is produced. The lowest resistance achieved is 0.9 Ω cured at 150°C for 60 minutes. The conductivity of the ink track was affected by curing process and cross-sectional area of the ink track. It is proven that a syringe deposition system is capable of printing the ink track and DLP projector with hot plate is suitable to cure the ink track properly on fabric

V sicules et v sicules polym riques Caract risations et applications

SIGLEBSE B225637Q / UCL - Université Catholique de LouvainBEBelgiu