10,626 research outputs found
Semantic Compression for Edge-Assisted Systems
A novel semantic approach to data selection and compression is presented for
the dynamic adaptation of IoT data processing and transmission within "wireless
islands", where a set of sensing devices (sensors) are interconnected through
one-hop wireless links to a computational resource via a local access point.
The core of the proposed technique is a cooperative framework where local
classifiers at the mobile nodes are dynamically crafted and updated based on
the current state of the observed system, the global processing objective and
the characteristics of the sensors and data streams. The edge processor plays a
key role by establishing a link between content and operations within the
distributed system. The local classifiers are designed to filter the data
streams and provide only the needed information to the global classifier at the
edge processor, thus minimizing bandwidth usage. However, the better the
accuracy of these local classifiers, the larger the energy necessary to run
them at the individual sensors. A formulation of the optimization problem for
the dynamic construction of the classifiers under bandwidth and energy
constraints is proposed and demonstrated on a synthetic example.Comment: Presented at the Information Theory and Applications Workshop (ITA),
February 17, 201
Strategies for Searching Video Content with Text Queries or Video Examples
The large number of user-generated videos uploaded on to the Internet
everyday has led to many commercial video search engines, which mainly rely on
text metadata for search. However, metadata is often lacking for user-generated
videos, thus these videos are unsearchable by current search engines.
Therefore, content-based video retrieval (CBVR) tackles this metadata-scarcity
problem by directly analyzing the visual and audio streams of each video. CBVR
encompasses multiple research topics, including low-level feature design,
feature fusion, semantic detector training and video search/reranking. We
present novel strategies in these topics to enhance CBVR in both accuracy and
speed under different query inputs, including pure textual queries and query by
video examples. Our proposed strategies have been incorporated into our
submission for the TRECVID 2014 Multimedia Event Detection evaluation, where
our system outperformed other submissions in both text queries and video
example queries, thus demonstrating the effectiveness of our proposed
approaches
TennisSense: a platform for extracting semantic information from multi-camera tennis data
In this paper, we introduce TennisSense, a technology platform for the digital capture, analysis and retrieval of tennis training and matches. Our algorithms for extracting useful metadata from the overhead court camera are described and evaluated. We track the tennis ball using motion images for ball candidate detection and then link ball candidates into locally linear tracks. From these tracks we can infer when serves and rallies take place. Using background subtraction and hysteresis-type blob tracking, we track the tennis players positions. The performance of both modules is evaluated using ground-truthed data. The extracted metadata provides valuable information for indexing and efficient browsing of hours of multi-camera tennis footage and we briefly illustrative how this data is used by our tennis-coach playback interface
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