Roger Liew

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Understanding the spatial preference of mobile and web users is of great significance to creating and improving location-based recommendation systems, travel planners, search engines, and other emerging mobile applications. However, traditional sources of spatial preference -- which reflect the patterns of geo-spatial interest of large numbers of users --(More)
The Ranque–Hilsch vortex tube (RHVT) is a device currently used to generate local cooling. In general, the fluid that is injected into the RHVT is a single-phase gas. In this study, however, we have added a dispersed phase (water droplets) to the gas (nitrogen). By means of phase Doppler particle analysis, three velocity components, their higher order(More)
We describe our experiences in applying learning-to-rank techniques to improving the quality of search results of an online hotel reservation system. The search result quality factors we use are average booking position and distribution of margin in top-ranked results. (We expect that total revenue will increase with these factors.) Our application of the(More)
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