Browsing by Author "Oberli, C."

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    Crowded pedestrian counting at bus stops from perspective transformations of foreground areas
    (INST ENGINEERING TECHNOLOGY-IET, 2012) Garcia Bunster, G.; Torres Torriti, M.; Oberli, C.
    Automated bus fleet scheduling and dispatch require an accurate measurements of current passenger demand. This study presents an effective holistic approach for estimating the number of people waiting at regular open bus stops by means of image processing. This is a non-trivial problem because of several varying conditions that complicate the detection process, such as illumination, crowdedness and different people poses, to name a few. The proposed method estimates the pedestrian count using measurements of foreground areas corrected by perspective. Four approaches are evaluated to find the best mapping between the area measurements and the people count. These mappings include two parametric (standard linear regression model, linear discriminant analysis) and two non-parametric (probabilistic neural network, k-nearest neighbours) approaches. This study also evaluates the performance of the algorithm when thermal and panoramic catadioptric cameras are used instead of standard perspective colour cameras. The proposed method is shown to yield better pedestrian count estimates than those obtained using milestone detectors, and requires model fitting procedures than can be easily implemented without requiring very large datasets for proper classifier training. The approach can also be employed to count people in other public spaces, such as buildings and crosswalks.
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    Multi-antenna testbeds for research and education in wireless communications
    (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2004) Rao, R.M.; Zhu, W.J.; Lang, S.; Oberli, C.; Browne, D.; Bhatia, J.; Frigon, J.F.; Wang, J.M.; Gupta, P.; Lee, H.; Liu, D.N.; Wong, S.G.; Fitz, M.; Daneshrad, B.; Takeshita, O.
    Wireless communication systems present unique challenges and trade-offs at various levels of the system design process. Since a variety of performance measures are important in wireless communications, a family of testbeds becomes essential to validate the gains reported by theory. Wireless testbeds also play a very important role in academia for training students and enabling research. In this article we discuss a classification scheme for wireless testbeds and present example testbeds developed at UCLA for each of these cases. We present the unique capabilities of these testbeds, provide results of experiments, and discuss the role they play in an educational environment.
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    PoQBA: A new path admission control for diffserv networks
    (2007) Pena, E.; Rios, M.; Oberli, C.; Marianov Kluge, Vladimir