Properties of some blind equalization criteria in noisy multiuserenvironments

Blind equalization in noisy multiuser channels has met with increasing attention with the advent of multiaccess digital communication systems. We examine blind equalizer performance in cases where perfect equalization proves unattainable due to noise and interference from concurrent users. In particular, we obtain a characterization of stationary points and extrema for a family of blind criteria in "undermodeled" cases, which assimilates the influence of differing source statistics and background noise correlation properties; relations to mean-square equalization measures are then obtained as a byproduct. By re-examining a gradient search procedure, we obtain domains of attraction of each extremum in a special "sufficient order" setting. We also derive a global step-size bound for undermodeled cases, which ensures convergence of a gradient search procedure to an extremum of a blind cost function. We likewise confirm that the super-exponential algorithm results from an optimal choice of this step-size parameter     

Antibodies to the HIV type 2 core protein p26 and Vpx: association with disease progression

A longitudinal cohort study was conducted to define the prevalence and temporal pattern of antibody response to the HIV-2 virion-associated proteins p26gag and Vpx. One hundred and forty-one asymptomatic HIV-2-infected women were enrolled, and followed for up to 11 years. Eighty-one percent of the subjects had antibodies to p26, and 51% to Vpx; response to these two antigens was not correlated. The response to both proteins was determined early in infection, and remained stable over time. The absence of antibodies to p26 was a highly significant predictor of CDC category IV HIV-related disease (p < 0.01) in both univariate and multivariate analysis. Antibody response to Vpx alone was not associated with disease progression. However, those individuals lacking anti-p26 antibodies, and with anti-Vpx antibodies, were six times more likely to be classified as CDC category IV by the end of the study (p < 0.01). This represents the first identification of virus-specific serological markers for HIV-2-related disease progression.     

LMS coupled adaptive prediction and system identification: astatistical model and transient mean analysis

The LMS algorithm has been successfully used in many system identification problems. However, when the input data covariance matrix is ill-conditioned, the algorithm converges slowly. To overcome the slow convergence, an adaptive structure is studied, which incorporates an LMS adaptive predictor (prewhitener) prior to the LMS algorithm for system identification (canceler). Since the prewhitener is also adaptive, the input to the LMS canceler is nonstationary, even when the input is stationary. Because of the coupling and the nonstationarity of LMS canceler input, analysis of the performance of the two adaptations is extremely difficult. A simple theoretical model of the coupled adaptations is presented and analyzed. First and second moment analysis indicates that the adaptive predictor significantly speeds up the LMS canceler as compared to a system without prewhitening and enlarges the stability domain of the canceler (larger allowable μ). Monte-Carlo simulations are presented which are in good agreement with the predictions of the mathematical model     

HIV infection in pregnant women in Dakar (Senegal)

The epidemiologic and sociodemographic characteristics of human deficiency virus (HIV) infection vary from one country to another. The objective of this study was to determine the prevalence of HIV infection in pregnant women in Dakar and associated factors. Systematic anonymous screening was performed in pregnant women admitted to the maternity ward. Women whose seropositivity was confirmed by Western blot retroviral serology were included. One woman out of four was assigned by simple random selection to the case control group. Over a 24 month period, 12,498 women were tested. 104 were seropositive (44 HIV1, 58HIV2, and 2 HIV1-HIV2 giving a prevalence of 0.8%. Factors associated with HIV1 and HIV2 were different: mean age 21.7 years for HIV1 versus 30.6 for HIV 2 (p = 0.05); origin in Guinea-Bissau for HIV2 (p = 0.001); mean number of pregnancies 2.6 for HIV1 versus 5.9 for HIV2 (p = 0.001); mean parity 1.5 for HIV1 versus 4.5 for HIV2 (p < 0.01); vitality of the conception product in 85.1% for HIV2 versus 67.5% for HIV1 (p = 0.0001). These data confirm the low prevalence of HIV infection in pregnant women, with a predominance for HIV2. The factors identified in associated with virus type suggest a different mode of transmission and/or reduced virulence or HIV2 compared with HIV1. Knowledge of these factors helps orient management strategies, especially in pregnant women.     

Algebraic change-point detection

Elementary techniques from operational calculus, differential algebra, and noncommutative algebra lead to a new approach for change-point detection, which is an important field of investigation in various areas of applied sciences and engineering. Several successful numerical experiments are presented.     

Subtype-specific polymerase chain reaction for the identification of HIV-1 genetic subtypes circulating in Africa

The association between cancer and the increased tendency for bleeding and clotting is well established. Many investigators have reported on the interaction between tumor-related and plasma-related factors that may be responsible for this predisposition in cancer patients. The precise role of any of these factors in thrombosis or bleeding remains speculative. A good understanding of the course of the underlying malignancy, mechanisms of actions of the agents used for treatment, and a high degree of clinical suspicion are required to direct practicing physicians towards an objective and timely diagnosis of these complications. The goal of this article is to provide a broad overview of a few important hemostatic problems encountered in cancer patients.     

收集正确的数据——保障妇女权益

在发展过程中，现行的性别主流化战略在解决贫困妇女问题方面还有很大的差距。这主要是由于现行的工具和手段所依赖的国别数据常常弩虑了城乡差别，而忽视了性别差异。     

On the existence of stationary points for the Steiglitz-McBridealgorithm

Most convergence results for adaptive identification algorithms have been developed in sufficient order settings, involving an unknown system with known degree. Reduced-order settings, in which the degree of the unknown system is underestimated, are more common, but more difficult to analyze. Deducing stationary points in these cases typically involves solving nonlinear equations, hence the sparseness of results for reduced-order cases. If we allow ourselves the tractable case in which the input to an identification experiment is white noise, we shall show that the Steiglitz-McBride method (1965) indeed admits a stationary point in reduced-order settings for which the resulting model is stable. Our interest in this study stems from a previous result, showing an attractive a priori bound on the mismodeling error at any such stationary point     

A privacy-preserving code-based authentication protocol for Internet of Things

The Journal of Supercomputing - The Internet of Things (IoT) is an upcoming technology that permits to interconnect different devices and machines using heterogeneous networks. One of the most...     

Comments on ‘Differentiator application in altitude control for an indoor blimp robot’

ABSTRACT

Comparison of several types of differentiation algorithms has been performed in the paper Wang, Zheng, Efimov, and Perruquetti [(2018). Differentiator application in altitude control for an indoor blimp robot. International Journal of Control, 1–10. Retrieved from https://doi.org/10.1080/00207179.2018.1441549] with application to a robotic blimp altitude control. Unfortunately, one of the differentiation methods, the algebraic differentiator, has not been applied properly. The clarifications and the new comparison results are given in this note.