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This paper deals with the application of the analytical model of quantization in order to characterize the uncertainty in the estimation of the amplitude of a sine wave with unknown offset through the discrete Fourier transform. It is shown that the conventional noise model of quantization in this case can lead to an underestimation of the uncertainty. The proposed analytical results are validated...
This paper deals with the problem of probabilistic detection of weak sine waves immersed in noise. The analysis is performed in the frequency domain after a discrete Fourier transform, and it is suited for real-time applications. The detection and false alarm probabilities are provided in analytical form as functions of the sampling parameters and the properties of the time window. In particular,...
In this paper, a new method to model and simulate a wireless communication system based on system on chip design methodology will be presented. The network performance effected by the amount of detail in the simulation model. Hence there is a need to develop suitable abstractions that maintain the accuracy of the simulation while keeping the computational resource requirements low. The integration...
In this paper for MB-OFDM piconets the probabilities of symbol collision and symbol skipping are theoretically analyzed in the case that both the desired and interfering piconets employ Adaptive Symbol Skipping (ASS). In this scheme energy detection is employed and symbol transmission is skipped in order to avoid collision. Thermal noise is taken into account for analysis of the probabilities are...
Finding the transport capacity of an arbitrary wireless network is generally considered as a difficult mathematics issue. In this work, from a unconventional perspective, we formulate it as a physical issue with lower complexity. Assuming that n identical nodes are located in a region of area A, transmit rate W, the transport capacity (in bit-meters per second) of the network has a "scaling law"...
A theory of non-autonomous dynamics of a strongly nonlinear spin-torque nano-oscillator in the presence of external periodic and/or chaotic (e.g. thermal noise) signals is developed. This theory is based on the nonlinear oscillator equation for the complex amplitude of a spin wave excited by spin polarized current. The nonlinearity of the spin-torque oscillator characterized by the coefficient v is,...
Multiple access interference in ultra-wide bandwidth systems is non-Gaussian distributed. Several non-Gaussian detectors have been proposed in the literature for improved signal detection in multiuser environments. The simplified Gaussian-Laplacian mixed model receiver which was derived based on a Laplacian model assumption for the distribution of the multiple access interference is known to perform...
This paper proposes an energy detection based time of arrival (TOA) estimation scheme for impulse radio ultra-wideband (IR-UWB) systems. The proposed scheme is composed of two stages in performing the TOA estimation: initial signal acquisition (ISA) and fine timing estimation (FTE). In the ISA stage, a linear quadrature optimization based weighting scheme is proposed to coarsely capture the arrival...
Orthogonal frequency division multiplexing (OFDM) system, known to be very practical for multipath environments, suffers from signal waveform with high peak-to-average power ratio (PAPR). As a consequence nonlinear distortion are introduced by the radio frequency (RF) components, such as amplitude clipping due to the low noise amplifier (LNA) in low cost receivers. This can significantly affect the...
The ever increasing amount of content on the Internet has fostered many efforts seeking to leverage this potentially yottascale information source. Service systems using advanced data and text analytics techniques have been developed to perform knowledge gathering and information discovery over Web data. Information gathered from free and public sources on the Web is frequently integrated with enterprise...
Performance of some suboptimal detectors can be improved by adding independent noise to their observations. In this paper, the effects of adding independent noise to observations of a detector are investigated for binary composite hypothesis-testing problems in a generalized Neyman-Pearson framework. Sufficient conditions are derived to determine when performance of a detector can or cannot be improved...
The advanced wireless communications such as the sensor networks and ad-hoc networks requires the communications system that is flexible about the transmission power control and robust over multiple access interference. We have showed that the throughput of Code Shift Keying (CSK) random access network is high with the transmission power control. However, it is difficult to use transmission power...
In this paper, the detection performance of OSGO and OSSO CFAR detectors embedded in heavy-tailed Pearson distributed clutter is analyzed. We derive the closed mathematic form expressions of probability of false alarm rate and detection probability of the two CFAR schemes. While the processing speed of OSGO and OSSO CFAR is two times of that of OS CFAR, simulation results indicate that OSGO CFAR detector's...
In this paper, an exact distribution of channel capacity for MISO (Multiple-Input Single-Output) system with co-channel interference is derived from the information theoretical viewpoint. It is found that the MISO channel capacity in the noise-limited channel follows the chi-square distribution, and capacity in the interference-limited channel follows the F-distribution. Using these distributions...
Consider a first order, linear and time-invariant discrete time system driven by Gaussian, zero mean white process noise, a pre-processor that accepts noisy measurements of the state of the system, and an estimator. The pre-processor and the estimator are not co-located, and, at every time-step, the pre-processor sends either a real number or an erasure symbol to the estimator. We seek the pre-processor...
This work proposes a distributed sampling design for the signal detection application in the cluster-based wireless sensor networks (WSNs). Considering the energy saving requirement in the cluster-based WSNs, a linear weighting data fusion scheme for data reduction at the cluster head is also developed in this paper. Both the distributed sampling and the data reduction schemes are designed based on...
We consider the problem of event detection in wireless sensor networks (WSNs) that are large in the sense that an event affects the statistics of the observations of a small number of sensors in the vicinity of where it occurs. An event occurs at a random time at a random location in the region (called the region of interest, ROI) covered by the WSN. We consider a distance based sensing model in which...
As a storage-unit of user created Web objects, the set has become an emerging challenge in the retrieval. Set search requires relevant sets to meet the information need of users, whereas traditional information retrieval focuses on finding relevant Web objects. This paper proposes a new approach to measure relevance of sets with respect to a user query by their topic coverage. The main idea of the...
In this paper, we present an effective approach to link the broken characters in online handwritten chemical formulas. By observing a large number of formula samples, we classify the common broken problems in online handwritten chemical formulas into three types, ldquopoint-likerdquo broken type, liner-type and arc-type. The proposed method combines the strokes characteristic of handwritten chemical...
Synthetic aperture radar (SAR) image contains undesired artifacts in the form of a granular look, which is called speckle. Methods previously proposed for speckle noise filtering suffer from two major limitations: 1) noise attenuation is not sufficient, especially in the smooth and background areas; 2) existing methods do not preserve or enhance edges sufficiently-they only inhibit smoothing near...
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