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Based on the requirements of a certain type of regional aircraft, the overheat detection system is designed to monitor bleed air leakage of the engines and APU (Auxiliary Power Unit). The detection system contains a series of overheat sensing elements, each of which is an inconel tube with center wire conductor embedded in the eutectic salt. The overheat alarm of the detection system can be triggered...
Crowdsensing systems collect large-scale sensor data from mobile devices to provide a wide-area view of phenomena including traffic, noise and air pollution. Because such data often exhibits sparse structure, it is natural to apply compressive sensing (CS) for data sampling and recovery. However in practice, crowd participants are often distributed highly unevenly across the sensing area, and thus...
The use of vibration mode localization in arrays of mechanically-coupled, nearly identical cantilevers has been studied for ultra-sensitive mass detection and analyte identification. The effects of geometrical design of the coupling overhang, cantilever length, as well as the number of identical coupled cantilevers on the magnitude enhancement with a small mass perturbation were previously reported...
The use of vibration mode localization in arrays of mechanically-coupled, nearly identical beam-shaped resonators has been studied for ultra-sensitive mass detection. In this paper, for the first time, we thoroughly summarized and compared different sensitivities of various cantilever structures on mass sensing. Meanwhile, from our analytical results, the expression of the highest sensitivity has...
In cognitive radio (CR), the spectrum sensing of the primary user (PU) may consume some electrical power from the battery capacity of the secondary user (SU), yielding to decrease the transmission power of the SU. In this paper, a multislot simultaneous spectrum sensing and energy harvesting model is proposed, which uses the harvested radio frequency (RF) energy of the PU signal to supply the spectrum...
In this paper, a multi-slot spectrum sensing and transfer scheme inmultichannel CR is proposed by dividing the sensing stage into several time slots that are allocated to the subchannels for spectrum sensing. We formulate an optimization problem that maximizes the SU's aggregate throughput by jointly allocating the optimal number of sensing time slots and transfer power to each subchannel. The simulation...
In cognitive radio, cooperative detection through optimization can improve the performance of spectrum sensing. In this paper, the optimal selection of cognitive radios including threshold optimization and cognitive radio's selection optimization is proposed, and the sensing mechanism including sensing period optimization and sensing time optimization is also analyzed. The proposed optimization algorithm...
This paper presents a fully integrated inductively powered implantable circuits for blood flow measurement, which are embedded within vascular prosthetic grafts for early detection of graft degradation or failure. The ASIC interfaces with micro-fabricated pressure sensors and uses a 13.56MHz carrier frequency for power transfer and command/data communication. A backscatter-modulated passive telemetry...
We study optimal transmission strategies in multi-channel cognitive radio networks where one secondary user (SU) opportunistically accesses multiple orthogonal channels that are owned and utilized by primary users (PU). In dynamic spectrum access networks, the protection of PU's is vital, since no PU would accommodate SU access to its own detriment. Therefore the objective of the problem we study...
Cognitive radio has the potential to improve spectrum efficiency and to alleviate spectrum scarcity by opportunistically utilizing un-utilized or under- utilized spectrum. A cognitive radio device needs to monitor primary user (PU) activities to identify white spaces and utilize spectral opportunities for transmission, without significantly affecting the PU performance. Additional challenges exist...
Cognitive radio (CR) is viewed as a novel approach for improving the utilization of radio electromagnetic spectrum resource, and spectrum detection is an important step of CR. As the traditional methods are detecting every channel orderly, and it does not satisfy the real-time needs of CR, a detection algorithm based on blind signal separation is proposed in this paper. Through the sensors, the mixed...
In cognitive wireless networks where secondary users (SUs) opportunistically access spectral white spaces of primary users (PUs), there exists an inherent tradeoff between sensing and transmission due to the competing goals of PU protection and SU access maximization. This paper studies means of sensing-transmission for SUs to better manage the competing goals by defining utility function to reward...
Meshless methods popularized in recent years are attractive choices for solving discontinuous and large deformation problems. As one of the most popular methods to form trial function, moving least squares (MLS) can accurately fulfill input signal reconstruction of nonlinear multiple-input multiple-output sensor. However, the parameter matrix obtained from MLS approximation sometimes is ill-conditioned...
Sensor transactions should be scheduled to preserve the temporal validity constraint of real-time data. In this paper, we propose a new algorithm called deferrable scheduling using time slice exchange. It defers the release time of a transaction instance as late as possible by exchanging its time slices with time slices for other transaction instances. Experiments show that it outperforms the Deferrable...
Least squares support vector machines (LSSVM), as a recently reported least squares version support vector machines (SVM), involves equality constraints instead of inequality constraints and adopts least squares cost function, therefore it expresses the training by solving a set of linear equations instead of the quadratic programming problem which greatly reduces computational cost. In this paper,...
The listen-Before-Talk (LBT) strategy has been prevalent in cognitive radio networks where secondary users opportunistically access under-utilized primary band. To minimize the amount of disruption from secondary users to primary signals, secondary users generally are required to detect the presence of the primary user reliably, and access the spectrum intelligently. The sensing time has to be long...
Cognitive Radio (CR) is an attractive technology to alleviate spectrum scarcity in wireless communications. It allows secondary users (SUs) to opportunistically access the licensed spectrum of primary users (PUs) so long as these users' communications are protected. Therefore, protection of the PUs is central to the adoption of this technology. In this paper, we consider an SU that must protect multiple...
Cognitive radio improves spectrum efficiency by allowing secondary users (SU) to dynamically exploit the idle spectrum owned by primary users (PU). This paper studies optimal bandwidth allocation for SUs. Consider the following tradeoff: a SU increases its instantaneous throughput by accessing larger bands, but channel switching overhead (due to the dynamics of PU activities) and contention among...
Driven by regulatory initiatives and radio technology advances, opportunistic spectrum access has the potential to mitigate spectrum scarcity and meet the increasing demand for spectrum. In this paper, we consider a scenario where secondary users can opportunistically access unused spectrum vacated by idle primaries. We introduce two metrics to protect primary performance, namely collision probability...
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