Physical Violence Detection Based on Distributed Surveillance Cameras

Mobile Networks and Applications - In recent years, physical violence detection has become a research hotspot in the area of human activity recognition. With the improvement and full coverage of...     

Ultrasound holographic B-scan imaging

An ultrasound holographic B-scan (UHB) imaging apparatus comprising a minicomputer system, a data acquisition unit, and a special 64-element UHB transducer has been developed. Simulation studies and real experiments with a tissue-equivalent phantom show that lateral and longitudinal resolution (-6 dB) of about 1 mm was achieved in the entire image. Furthermore, results from clinical evaluation, including diagnostic and neurosurgical imaging, suggest that the UHB imaging method is operational and has some special advantages in patient diagnosis. Theoretically, the addition of phase information to the ultrasound images can result in enhanced tissue characterization, which is extremely important in tumor diagnosis and treatment.     

A Multi-sensor School Violence Detecting Method Based on Improved Relief-F and D-S Algorithms

Mobile Networks and Applications - School bullying is a common social problem, and school violence is considered to be the most harmful form of school bullying. Fortunately, with the development of...     

Frequency domain compensation for inhomogeneous layers in ultrasound holography

A frequency-domain compensation method is presented that is based on the ultrasound holography B-scan (UHB) imaging principle. In an acoustic imaging system, the wavefront-angle-dependent distortions caused by any kind of known inhomogeneous reason can be compensated by this method. It is applied here in the frequency domain using the so-called rear-ranging operation for the longitudinal distortion and the multiplication of phase factors for the lateral distortion. The method is especially suitable for compensating different velocity layers in acoustic imaging systems. The results of both computer simulations and water-tank experiments are promising.     

Receiver-Controlled Multi-Node Cooperation

Since wireless links in Ad hoc networks are more fragile than those in traditional wireless networks due to route flapping, multi-node cooperation plays an important role in ensuring the quality of service （QoS）. Based on the authors＇ previous work, this paper proposes a receiver-controlled multi-node cooperation routing protocol, known as AODV-RCC. In this protocol, nodes form a cooperation group based on signal power. In a cooperation group, signal power between a partner and a transmitter, as well as signal power between the partner and the receiver, must be larger than the signal power between the transmitter and the receiver. Otherwise, the transmission will not benefit from cooperation. To avoid collision or congestion, each cooperation group only contains one partner. This partner offers both data and ACK cooperative retransmission. Its retransmission time should be shorter than the internal retry time of the transmitter＇ s MAC layer, because it is better for the partner to retransmit firstly, as it offers a more reliable cooperative link. In AODV-RCC, it is the receiver that chooses the partner, because the link between the partner and the receiver is the most important. According to our simulation results, AODV-RCC shortens the end-to-end delay and increases the packet delivery ratio.