Estimating snow cover from publicly available images

In this paper we study the problem of estimating snow cover in mountainous regions, that is, the spatial extent of the earth surface covered by snow. We argue that publicly available visual content, in the form of user generated photographs and image feeds from outdoor webcams, can both be leveraged as additional measurement sources, complementing existing ground, satellite and airborne sensor data. To this end, we describe two content acquisition and processing pipelines that are tailored to such sources, addressing the specific challenges posed by each of them, e.g., identifying the mountain peaks, filtering out images taken in bad weather conditions, handling varying illumination conditions. The final outcome is summarized in a snow cover index, which indicates for a specific mountain and day of the year, the fraction of visible area covered by snow, possibly at different elevations. We created a manually labelled dataset to assess the accuracy of the image snow covered area estimation, achieving 90.0% precision at 91.1% recall. In addition, we show that seasonal trends related to air temperature are captured by the snow cover index.Comment: submitted to IEEE Transactions on Multimedi

Spartan Daily September 25, 2018

Volume 151, Issue 15https://scholarworks.sjsu.edu/spartan_daily_2018/1057/thumbnail.jp

Listening to Garhwali Popular Music in and out of Place

Listening to popular music is a central means by which people construct their place in the world, both literally and figuratively. For Garhwalis living inside and outside of the Himalayas, listening to vernacular popular music has been one way in which they imagine themselves to be part of a specific place and a larger cultural region. Displacement is a major theme of these songs, and practices of listening underline the mobile and trans-local aspects of life for many Garhwalis. In order to assess the impact of popular music consumption on notions of place, and vice versa, this article provides ethnographic vignettes of musical consumption in Garhwali villages and small towns, Garhwali pilgrimage sites, and migrant contexts outside of Garhwal. I suggest that much of the emotional salience and enduring popularity of Garhwali gīt derive from the emotional and physical displacement of married women and male migrants

Online Popularity and Topical Interests through the Lens of Instagram

Online socio-technical systems can be studied as proxy of the real world to investigate human behavior and social interactions at scale. Here we focus on Instagram, a media-sharing online platform whose popularity has been rising up to gathering hundred millions users. Instagram exhibits a mixture of features including social structure, social tagging and media sharing. The network of social interactions among users models various dynamics including follower/followee relations and users' communication by means of posts/comments. Users can upload and tag media such as photos and pictures, and they can "like" and comment each piece of information on the platform. In this work we investigate three major aspects on our Instagram dataset: (i) the structural characteristics of its network of heterogeneous interactions, to unveil the emergence of self organization and topically-induced community structure; (ii) the dynamics of content production and consumption, to understand how global trends and popular users emerge; (iii) the behavior of users labeling media with tags, to determine how they devote their attention and to explore the variety of their topical interests. Our analysis provides clues to understand human behavior dynamics on socio-technical systems, specifically users and content popularity, the mechanisms of users' interactions in online environments and how collective trends emerge from individuals' topical interests.Comment: 11 pages, 11 figures, Proceedings of ACM Hypertext 201