Blind adaptive equalizer for broadband MIMO time reversal STBC based on PDF fitting

In this paper, we propose a new blind adaptive technique used for the equalisation of space-time block coded (STBC) signals transmitted over a dispersive MIMO channel. The proposed approach is based on minimising the difference between the probability density function (PDF) of the equalizer output — estimated via the Parzen window method — and a desired PDF based on the source symbols. The cost function combines this PDF fitting with an orthogonality criterion derived from the STBC structure of the transmitted data in order to discourage the extraction of identical signals. This cost function motivates an effective and low-cost stochastic gradient descent algorithm for adapting the equaliser. The performance is demonstrated in a number of simulations and benchmarked against other blind schemes for the equalisation of STBC over broadband MIMO channels

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None

Doping Dependence of Thermal Oxidation on n-type 4H-SiC

The doping dependence of dry thermal oxidation rates in n-type 4H-SiC was investigated. The oxidation was performed in the temperature range 1000C to 1200C for samples with nitrogen doping in the range of 6.5e15/cm3 to 9.3e18/cm3, showing a clear doping dependence. Samples with higher doping concentrations displayed higher oxidation rates. The results were interpreted using a modified Deal-Grove model. Linear and parabolic rate constants and activation energies were extracted. Increasing nitrogen led to an increase in linear rate constant pre-exponential factor from 10-6m/s to 10-2m/s and the parabolic rate constant pre-exponential factor from 10e9m2/s to 10e6m2/s. The increase in linear rate constant was attributed to defects from doping-induced lattice mismatch, which tend to be more reactive than bulk crystal regions. The increase in the diffusion-limited parabolic rate constant was attributed to degradation in oxide quality originating from the doping-induced lattice mismatch. This degradation was confirmed by the observation of a decrease in optical density of the grown oxide films from 1.4 to 1.24. The linear activation energy varied from 1.6eV to 2.8eV, while the parabolic activation energy varied from 2.7eV to 3.3eV, increasing with doping concentration. These increased activation energies were attributed to higher nitrogen content, leading to an increase in effective bond energy stemming from the difference in C-Si (2.82eV) and Si-N (4.26eV) binding energies. This work provides crucial information in the engineering of SiO2 dielectrics for SiC MOS structures, which typically involve regions of very different doping concentrations, and suggests that thermal oxidation at high doping concentrations in SiC may be defect mediated.Comment: 13 pages. 9 figures, accepted as a transiction in IEEE electron device. TED MS#8035

Haptic Feedback for Wrist Angle Adjustment

Haptic feedback is envisioned to be a powerful tool in (digital) orthosis fitment procedures. In context of a larger research project on digital molding and developing a glove for orthopedic experts, we explored the use of vibrotactile feedback on the wrist for wrist angle adjustments. Five different patterns are presented on both the inside and outside of the wrist as well as crossing signals. Participants were asked to indicate whether the pattern was communicating that the wrist angle had to be increased or decreased by moving the hand up or down. The results show that the vibrotactile stimuli are being interpreted consistently by the participants, provided the patterns are presented on one side of the arm. Although the interpretations were consistent within participants, there were individual differences in the reported directions of the signals, which makes it important to take into account personal preferences and calibration when implementing haptic feedback

Marine pollution effects on the reproduction process of Perinereis cultrifera (Annelida, Polychaeta) in Algeria

The Mediterranean Sea is one of the busiest areas worldwide in terms of maritime activity and faces considerable anthropogenic disturbances, such as pollution by hydrocarbons and heavy metals. This study evaluated the environmental status of three sites on the Algerian coast using the annelid polychaete Perinereis cultrifera as a biomonitoring sentinel species. It included different reproductive parameters such as oocyte diameter, frequency distributions, sexual maturity index, biochemical quantitative parameters represented by the vitellogenins and vitellins, and a histological study of the coelome during the reproductive period. The results showed that the females collected from El-Kala (healthy site) have the highest diameter 304.1 ± 24.3 μm during April but the values were increased in Annaba 290.0 ± 21.0 μm and Skikda 245.3 ± 26.7 μm. Significant differences were observed between worms from the three study sites during the three months of the study. Moreover, the size-frequency indicated that a relatively high proportion of females containing mature oocytes was found in April in females collected at El-Kala 52.4%, 46.4% in females collected at Annaba and 36.7% in females collected at Skikda. In addition, regarding the sexual maturity index, the highest values were recorded in April (3.8, 2.9, and 1.9) at the El-Kala, Annaba, and Skikda study sites. However, the biochemical analysis demontrated that the highest mean concentration of vitellogenin was in females of El-Kala (5.3 ± 0.3 µg/mg of coelomic fluid) in April, and the lowest mean concentration was measured in females of Skikda (1.5 ± 0.2 µg/mg of coelomic fluid). Therefore, the highest mean concentration of vitellin was measured in females of El-Kala (4.4 ± 0.2 µg/mg of oocytes) in April, while the lowest mean concentration of vitellin was measured in females of Skikda (1.02 ± 0.2 µg/mg of oocytes) in May. Significant differences were observed between worms from the three sites during the three months of the study. Furthermore, histological observations revealed that oogenesis was asynchronous, with oocytes at different stages of vitellogenesis simultaneously present. The structure of the oocytes of females collected at El-Kala showed intense vitellogenic activity due to the presence of very dense yolk cells. In contrast, the oocytes of the females collected from the two polluted sites (Annaba and Skikda) were small, vitellogenesis presented low intensity, and yolk cells were less frequent at the periphery and less uniform at the cytoplasmic mass; the nucleus was smaller, indicating a slower vitellogenic activity. These observations confirm the previously obtained results

Morphological characterization and clinical effects of stromal alterations after intracorneal ring segment implantation in keratoconus

Purpose To analyze the histological and (ultra)structural stromal tissue changes after femtosecond (Fs) laser–assisted intra corneal ring segment (ICRS) implantation and their refractive and topographic efects in patients with keratoconus. Methods This monocentric retrospective case series included 15 consecutive patients with clinical peri-segmental lamellar channel deposits after treatment with Fs-ICRS implantation for keratoconus. The stromal changes were investigated using in vivo confocal microscopy. Two patients underwent a penetrating keratoplasty after the Fs-ICRS implantation; the explanted corneas were processed for histopathology and transmission electron microscopy (TEM). Refractive and topographic efects were investigated comparing the uncorrected (UDVA) and corrected (CDVA) distance visual acuity, spherical equivalent (SE), fat (K1), steep (K2), and steepest (Kmax) keratometry before and after detection of lamellar channel deposits. Results In vivo confocal microscopy revealed difuse linear and focal granular hyperrefective structures. Histologically, there was mild proliferation of fbroblasts and fbrosis. TEM demonstrated focal accumulations of degenerated keratocytes with cytoplasmic lipid inclusions. There were no signifcant changes for UDVA (Δ=0.0±0.2 logMAR; p=0.67), CDVA (Δ=0.0±0.1 logMAR; p=0.32), SE (Δ 0.1±0.9 D; p=0.22), K1 (Δ=0.3±1.0 D; p=0.28), K2 (Δ=0.1±0.9 D; p=0.51), and Kmax (Δ=0.3±1.5 D; p=0.17). Conclusions Two types of structural stromal changes were identifed: (1) difuse peri-segmental fbrosis and (2) lamellar channel deposits. These structural changes showed no evidence of a relevant refractive or topographic efect

Who drops out and when? Predictors of nonresponse and loss to follow-up in a longitudinal cohort study among STI clinic visitors

Acknowledgments The authors would like to thank Joran Slager, who assisted with the data collection and contributed to the data analyses. Furthermore, the authors thank the staff at the STI clinics of Amsterdam, Kennemerland, Hollands Noorden, Twente, especially Karin Westra, Anne de Vries, Karlijn Kampman, and Titia Heijman, who were involved in the recruitment and data collection of participants at baseline. The authors are also grateful to Marlous Ratten and Klazien Visser from Soapoli-online, who coordinated the laboratory testing of the home-based test kits at six-month follow-up, and to the staff at the STI department at the National Institute for Public Health and the Environment, especially Birgit van Benthem.Peer reviewedPublisher PD

Palestinian Banks Analysis Using CAMEL Model

This study attempts to evaluate the performance and financial soundness of Palestinian commercial banks for the year 2015 using CAMEL rating model. The CAMEL model provides a means to categorized bank based on the overall health, financial status, and managerial operation. Banks were sustained rating based on the performance in five areas: capital adequacy, asset quality, management efficiency, earning quality, and liquidity. We applied capital adequacy ratio (CAR) to analyze capital adequacy parameter, non performing loans to total loans (NPL) to analyze of assets quality parameter, non expense ratio (NER) for analyzing management quality parameter, return on assets (ROA) and return on equity (ROE) to analyze earnings ability and total loans to total deposits ratio (LDR) to analyze liquidity management Keywords: CAMEL approach; financial institutions; Palestine JEL Classifications: G20; G2