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Social and Behavioral Sciences Commons™
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Full-Text Articles in Social and Behavioral Sciences
Pattern Exploration And Event Detection From Geo-Tagged Tweets, Yugian Huang
Pattern Exploration And Event Detection From Geo-Tagged Tweets, Yugian Huang
Open Access Theses
Twitter is one of the most famous social networking services in the world. With 313 million monthly active users, Twitter can produce around 6,000 tweets per second, which corresponds to around 500 million tweets per day and around 200 billion tweets per year. Besides being a successful company, Twitter provides a great opportunity to scientists from various disciplines. Twitter allows users to tweet with a location tag, which enables the connection of virtual networks to the events happening in real life. Because of the massive amount of valuable geographic information, location-based services, targeted advertising, and social network studies could benefit …
Manifold Learning Based Spectral Unmixing Of Hyperspectral Remote Sensing Data, Jun-Hwa Chi
Manifold Learning Based Spectral Unmixing Of Hyperspectral Remote Sensing Data, Jun-Hwa Chi
Open Access Dissertations
Nonlinear mixing effects inherent in hyperspectral data are not properly represented in linear spectral unmixing models. Although direct nonlinear unmixing models provide capability to capture nonlinear phenomena, they are difficult to formulate and the results are not always generalizable. Manifold learning based spectral unmixing accommodates nonlinearity in the data in the feature extraction stage followed by linear mixing, thereby incorporating some characteristics of nonlinearity while retaining advantages of linear unmixing approaches. Since endmember selection is critical to successful spectral unmixing, it is important to select proper endmembers from the manifold space. However, excessive computational burden hinders development of manifolds for …
Identifying Ditch Geometry And Top Of The Bank Location Using Airborne Lidar Point Cloud, Naime Celik
Identifying Ditch Geometry And Top Of The Bank Location Using Airborne Lidar Point Cloud, Naime Celik
Open Access Theses
The geometry of agricultural drainage ditches is very important in crop production as it impacts drainage of cropland and affects vegetation and soil erosion along the banks of the ditches. Thus, implementation of water conservation and management practices in engineered and natural ditches necessitates determination of ditch geometry along the reach of the ditch. This study explores the use of airborne commercial Light Detection and Ranging (LiDAR) technology to identify the top of the ditch banks. The method was developed to obtain the normalized cross sectional shape of the ditch using one-dimensional spline fits to ground classified points from the …