The process of adding high-density information onto printed material enables and improves interesting hardcopy document applications, such as: security, authentication, physical-electronic round ...tripping, item-level tagging as well as consumer/product interaction. This investigation on robust and high capacity print codes aims to maximize information payload in a given printed page area, subject to robustness to distortions originated by printing and scanning processes and also to degradations introduced by user manipulation of printed documents. The novel approach includes statistical print-and-scan channel characterization, designing of robust segmentation, unsupervised Bayesian color classification with expectation-maximization algorithm for parameters estimation of a mixture of Gaussians model and design of error correction codes. Results illustrate the performance evaluated under real channel and distortions conditions. High payload is achieved with sufficient robustness to distortions resulting of regular office hardcopy document handling: print-and-scan channel and user manipulation.
In this paper, it is shown that the least-mean fourth (LMF) adaptive algorithm is not mean-square stable when the regressor input is not strictly bounded (as happens, for example, if the input has a ...Gaussian distribution). For input distributions with infinite support, even for the Gaussian distribution, the LMF always has a nonzero probability of divergence, no matter how small the step-size is chosen. This result is proven for a slight modification of the Gaussian distribution in a one-tap filter and corroborated with several simulations. In addition, an upper bound is given for the probability of divergence of LMF as a function of the filter length, input power, step-size, and noise variance, for the case of Gaussian regressors. The results reported in this paper provide tools for designers to better understand the behavior of the LMF algorithm and decide on the convenience or not of its use for a given application.
Germ cell tumors are not so frequent; among them, teratomas are most common in the mediastinal location. Teratomas in young men are usually malignant (teratocarcinoma), with a gender ratio of 13.5:1, ...and an average age of 26 years. We describe the evolution of a 19-year-old man with a mediastinal tumor, with pulmonary metastases and intracardiac infiltration, successfully removed; whose most frequent symptoms were: dyspnea, retrosternal pain, fever, cough, weight loss and superior vena cava syndrome. The diagnosis was made by chest x-ray and computed tomography. Total removal of the tumor and metastases was achieved, as well as the intracardiac tumor, with tricuspid valve repair. The patient had a satisfactory outcome during the first follow-up year.
We investigated changes in symptoms and quality of life (QoL) in men with moderate-to-severe lower urinary tract symptoms associated with benign prostatic hyperplasia (LUTS/BPH) receiving the hexanic ...extract of
(HESr) and compared results with a matched group on watchful waiting (WW). Data was from a real-world, open-label, prospective, multicenter study. This sub-group analysis included patients with moderate-to-severe symptoms receiving either the HESr 320 mg/daily for six months (HESr) or who remained untreated for LUTS/BPH (WW). Changes in urinary symptoms and QoL were measured by IPSS and BII questionnaires. Two statistical approaches (iterative matching and propensity score pairing) were used to maximize between-group comparability at baseline. Tolerability was assessed in the HESr group. After iterative matching, data for analysis was available for 783 patients (102 WW, 681 HESr). IPSS scores improved by a mean (SD) of 3.8 (4.4) points in the HESr group and by 2.2 (4.5) points in the WW group (
= 0.002). Changes in BII score were 1.8 (2.4) points and 1.0 (2.2) points, respectively (
< 0.001). Three patients (0.9%) treated with the HESr reported mild adverse effects. Moderate-severe LUTS/BPH patients treated for six months with the HESr showed greater improvements in symptoms and QoL than matched patients on WW, with a very low rate of adverse effects.
This paper presents a new statistical analysis of the affine projection (AP) algorithm. An analytical model is derived for autoregressive (AR) inputs for unity step size (fastest convergence). ...Deterministic recursive equations are derived for the mean AP weight and mean-square error for large values of N (the number of adaptive taps). The value of N is also assumed large compared to the algorithm order (number of input vectors used to determine the weight update direction). The model predictions display better agreement with Monte Carlo simulations in both transient and steady-state than models previously presented in the literature. The model's accuracy is sufficient for most practical design purposes.
We consider random geometric graphs on the plane characterized by a non-uniform density of vertices. In particular, we introduce a graph model where \(n\) vertices are independently distributed in ...the unit disc with positions, in polar coordinates \((l,\theta)\), obeying the probability density functions \(\rho(l)\) and \(\rho(\theta)\). Here we choose \(\rho(l)\) as a normal distribution with zero mean and variance \(\sigma\in(0,\infty)\) and \(\rho(\theta)\) as an uniform distribution in the interval \(\theta\in 0,2\pi)\). Then, two vertices are connected by an edge if their Euclidian distance is less or equal than the connection radius \(\ell\). We characterize the topological properties of this random graph model, which depends on the parameter set \((n,\sigma,\ell)\), by the use of the average degree \(\left\langle k \right\rangle\) and the number of non-isolated vertices \(V_\times\); while we approach their spectral properties with two measures on the graph adjacency matrix: the ratio of consecutive eigenvalue spacings \(r\) and the Shannon entropy \(S\) of eigenvectors. First we propose a heuristic expression for \(\left\langle k(n,\sigma,\ell) \right\rangle\). Then, we look for the scaling properties of the normalized average measure \(\left\langle \overline{X} \right\rangle\) (where \(X\) stands for \(V_\times\), \(r\) and \(S\)) over graph ensembles. We demonstrate that the scaling parameter of \(\left\langle \overline{V_\times} \right\rangle=\left\langle V_\times \right\rangle/n\) is indeed \(\left\langle k \right\rangle\); with \(\left\langle \overline{V_\times} \right\rangle \approx 1-\exp(-\left\langle k \right\rangle)\). Meanwhile, the scaling parameter of both \(\left\langle \overline{r} \right\rangle\) and \(\left\langle \overline{S} \right\rangle\) is proportional to \(n^{-\gamma} \left\langle k \right\rangle\) with \(\gamma\approx 0.16\).
We study transport properties of bulk-disordered quasi-one-dimensional (Q1D) wires paying main attention to the role of long-range correlations embedded into the disorder. First, we show that for ...stratified disorder for which the disorder is the same for all individual chains forming the Q1D wire, the transport properties can be analytically described provided the disorder is weak. When the disorder in every chain is not the same, however it has the same binary correlator, the general theory is absent. Thus, we consider the case when only one channel is open and all others are closed. For this situation we suggest a semianalytical approach which is quite effective for the description of the total transmission coefficient. Our numerical data confirm the validity of this approach.
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Acoustic feedback is one of the main problems in modern hearing aids. It distorts the desired signal and limits the maximum stable gain. Results on acoustic feedback cancellation systems based on the ...prediction error method of closed-loop identification indicate that they perform better than most alternative solutions. Most available analyses of such systems, however, are limited to steady-state results. This paper presents a transient mean-square analysis of a recently proposed system. The structure is analyzed for slow adaptation and for autoregressive input signals. Analytical models are derived for the mean and mean-square adaptive weight behaviors. This includes a model for the transient behavior of the bias in the feedback path estimator. Monte Carlo simulations are presented to verify the accuracy of the derived models.
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