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This paper investigates the ambiguities that exist in the bearing estimate of human footstep signals acquired using a single tri-axial geophone. Estimated angles for a series of footsteps from three different walking patterns are evaluated. It is observed that there are two kinds of ambiguities, viz., energy and wave polarization. A systematic study of these ambiguities are presented using covariance...
A new spectrum sensing method based on the joint use of local polynomial time frequency transform (LPTFT) and Hough transform (HT) is proposed. Theoretical analysis of the detection probability of the proposed method and the associated statistical models are provided. The proposed method is used for sensing the wireless microphone (WM) signals in cognitive radio (CR) and the experimental results based...
Clustering is used extensively in wireless sensor networks to optimize lifetime. Within clustering, the optimization of cluster head (CH) location is critical since CHs consume energy faster and have greater influence on lifetime than non cluster head (NCH) sensors. Energy harvesting wireless sensor networks (EH-WSNs) use energy harvesting devices to harvest energy from environment. In contrast with...
In this paper, a new method is proposed to optimize the projection matrix, which, unlike the existing approaches, attempts to choose the projection matrix such that the sensing matrix is as close to a tight frame/equiangular tight frame as possible. In the proposed method, there are two important procedures that are used to adjust the Gram matrix of the sensing matrix. The simulation results are presented...
Accurate clinical assessment of a patient's condition is paramount to providing the type and intensity of therapy for patients. Currently, typical objective assessments require therapists to subjectively grade various tasks patients have to do. Also, the administration of these assessments are onerous and error prone. In our approach we embed sensors into objects used in the assessments. By using...
We propose a new source localization algorithm for the development of a touch interface using surface-mounted sensors. This algorithm allows one to convert a hard surface into a touch pad. The proposed algorithm is based on triangulation using phase transit time-differences-of-arrival (TDOA) between the received signals from the sensors. In this inter-disciplinary research, we analyze the wave propagation...
Cognitive radios rely on spectrum sensing to determine the presence of the primary system. The secondary system should not only sense the primary system but also exploit the transmission opportunities that are available in the spatial, spectral and temporal domains. Additional information regarding the location of the primary transmitter and receivers helps utilize the spatial opportunities. In this...
Limited natural energy resources compel humankind to search for efficient utilization of energy, and thus increasing number of fluorescent lamps are adopted for lighting systems. However, previous study showed that there exists a tradeoff between energy-saving and lifespan for fluorescent lamps. Consequently, it becomes an important topic on how to design an efficient and effective automatic control...
Filter banks facilitate an estimation of the power spectral density of broad-band non-stationary signals, an operation required in many cognitive radio systems. The samples at the filter bank output may serve as a basis for an estimation of the input signal energy within any time-frequency (TF) region of interest. In order to achieve a high resolution in both time and frequency, the prototype window...
This paper investigates the use of a new mask for the degenerate unmixing estimation technique (DUET) based on autocorrelation function (ACF) for spectrally correlated sound source localization (SCSSL), such as a helicopter, in time-frequency domain (TFD). Helicopter is a good example of spectrally correlated sound sources since the main and tail rotors of a helicopter are simultaneously turning by...
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