Hwee San Lim

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Road deposited sediments (RDS) are a valuable environmental medium for characterizing contaminant levels in urban areas; and their associated potentially toxic elements (PTEs) can directly impact both human and aquatic health. In this study, RDS were collected from 15 co-located industrial and residential roads throughout Singapore to determine the effect(More)
Nowadays visual information becomes more and more important in almost all areas of our life. This information is represented and processed digitally. Digital image processing is ubiquitous, with applications ranging from television to tomography, from photography to printing, from robotics to remote sensing. In this study, we developed an algorithm to(More)
Atmospheric corrections for multi-temporal optical satellite images are necessary, especially in change detection analyses, such as normalized difference vegetation index (NDVI) rationing. Abrupt change detection analysis using remote-sensing techniques requires radiometric congruity and atmospheric correction to monitor terrestrial surfaces over time. Two(More)
This paper presents a transmittance measurements technique collected by using FieldSpec HandHeld (Fieldspec HH) spectroradiometer to derive the aerosol optical thickness (AOT) in the atmosphere at 550nm to improve the particulate matters of less than 10 micron (PM10) concentrations mapping. The concentrations of PM10 at selected locations were measured(More)
Total column ozone obtained from the Ozone Monitoring Instrument (OMI) on board the Aura satellite was utilized to examine the spatial and temporal distribution of atmospheric ozone over Peninsular Malaysia for the year of 2015. The monthly ozone maps were obtained from the NASA-operated Giovanni portal (http://disc.sci.gsfc.nasa.gov/giovanni). Ozone has an(More)
Specific deficits in the processing of transient visual stimuli have been identified in reading-disabled children, and it has been shown that the filtering out of some medium to high spatial frequencies and some visible wavelengths impacts on their performance in a number of visual tasks. To assess further how these light diffusing and colour filtering(More)
The filter media in biofiltration systems play an important role in removing potentially harmful pollutants from urban stormwater runoff. This study compares the heavy metal removal potential (Cu, Zn, Cd, Pb) of five materials (potting soil, compost, coconut coir, sludge and a commercial mix) using laboratory columns. Total/dissolved organic carbon(More)
This study aims to investigate and establish a suitable model that can help to estimate aerosol optical depth (AOD) in order to monitor aerosol variations especially during non-retrieval time. The relationship between actual ground measurements (such as air pollution index, visibility, relative humidity, temperature, and pressure) and AOD obtained with a(More)
Remote sensing techniques have been used to study the impacts of the tropical cyclone. In order to figure out the relationship of typhoon with orography effect, precipitation products are acquired from Feng Yun 2D; and Global Digital Elevation Model (GDEM) from ASTER satellite was applied as well. After combining both the precipitation and elevation(More)