Compressive Sensing for Feedback Reduction in MIMO Broadcast Channels

We propose a generalized feedback model and compressive sensing based opportunistic feedback schemes for feedback resource reduction in MIMO Broadcast Channels under the assumption that both uplink and downlink channels undergo block Rayleigh fading. Feedback resources are shared and are opportunistically accessed by users who are strong, i.e. users whose channel quality information is above a certain fixed threshold. Strong users send same feedback information on all shared channels. They are identified by the base station via compressive sensing. Both analog and digital feedbacks are considered. The proposed analog & digital opportunistic feedback schemes are shown to achieve the same sum-rate throughput as that achieved by dedicated feedback schemes, but with feedback channels growing only logarithmically with number of users. Moreover, there is also a reduction in the feedback load. In the analog feedback case, we show that the propose scheme reduces the feedback noise which eventually results in better throughput, whereas in the digital feedback case the proposed scheme in a noisy scenario achieves almost the throughput obtained in a noiseless dedicated feedback scenario. We also show that for a fixed given budget of feedback bits, there exist a trade-off between the number of shared channels and thresholds accuracy of the feedback SINR.Comment: Submitted to IEEE Transactions on Wireless Communications, April 200

Fireside corrosion degradation of ferritic alloys at 600°C in oxy-fired conditions

This paper reports the results of a study carried out to investigate the effects of simulated coal/biomass combustion conditions on the fireside corrosion. The 1000 h deposit recoat exposure (5 × 200 h cycles) was carried out at 600 °C. In these tests ferritic alloys were used 15Mo3, T22, T23 and T91. Kinetics data were generated for the alloys exposed using both traditional weight change methods and metal loss measurements. The highest rate of corrosion based on EDX results occurred under D1 deposit where provoke mainly by the formation of alkali iron tri-sulphate phase

Validation of a Novel Methodology for Evaluating Surgical Tissue Plane Identification

Introduction: The ability to identify tissues planes is a fundamental surgical skill. This study attempts to validate a previously developed test for assessing this ability. Methods: 48 video captured images from laparoscopic right hemicolectomies were presented on an iPad to 18 surgeons who were grouped based on experience (Consultants (C), Senior trainees (S), and the Junior trainees (J)). Subjects were asked to draw a line indicating the tissue plane of dissection. Lines were compared by a modified Hausdorff measure. Within group variability represented group precision and trainee accuracy was determined from comparison to Consultants. Results: Within group comparisons demonstrated Consultants to be most precise with statistical significance in 14/25 images. Comparing Seniors and Juniors with Consultants demonstrated Seniors were significantly more accurate than Juniors in 14/22 images. Conclusion: This tool is sufficiently sensitive to discriminate between surgeons of different levels of experience based on measures of precision and accuracy

Polo like kinase 2 tumour suppressor and cancer biomarker: new perspectives on drug sensitivity/resistance in ovarian cancer

The polo-like kinase PLK2 has recently been identified as a potential theranostic marker in the management of chemotherapy sensitive cancers. The methylation status of the PLK2 CpG island varies with sensitivity to paclitaxel and platinum in ovarian cancer cell lines. Importantly, extrapolation of these in vitro data to the clinical setting confirms that the methylation status of the PLK2 CpG island predicts outcomes in patients treated with carboplatin and paclitaxel chemotherapy. A second cell cycle regulator, p57Kip2, is also subject to epigenetic silencing in carboplatin resistance in vitro and in vivo, emphasising that cell cycle regulators are important determinants of sensitivity to chemotherapeutic agents and providing insights into the phenomenon of collateral drug sensitivity in oncology. Understanding the mechanistic basis and identification of robust biomarkers to predict collateral sensitivity may inform optimal use of chemotherapy in patients receiving multiple lines of treatment

Reliability growth of open source software using defect analysis

We examine two active and popular open source products to observe whether or not open source software has a different defect arrival rate than software developed in-house. The evaluation used two common models of reliability growth models; concave and S-shaped and this analysis shows that open source has a different profile of defect arrival. Further investigation indicated that low level design instability is a possible explanation of the different defect growth profile. © 2008 IEEE

Numerical Comparison of Methods for Hirota-Satsuma Model

This paper outlines the implementation of the modified decomposition method (MDM) to solve a very important physical model namely Hirota-Satsuma model which occurs quite often in applied sciences. Numerical results and comparisons with homotopy perturbation (HPM) and Adomian’s decomposition (ADM) methods explicitly reveal the complete reliability of the proposed MDM. It is observed that the suggested algorithm (MDM) is more user-friendly and is easier to implement compared to HPM and ADM

A comparison of the reliability growth of open source and in-House software

As commercial developers have established processes to assure software quality, open source software depends largely on community usage and defect reporting to achieve some level of quality. Thus, quality of open source software may vary. We examined defects reported in two active and popular open source software projects and an in-house project. The results of this analysis indicate that the reliability growth of each is quite distinct and that the defect profile of open source software appears to be a consequence of the open source software development method itself. © 2008 IEEE