Why Does a Kronecker Model Result in Misleading Capacity Estimates?

Many recent works that study the performance of multi-input multi-output (MIMO) systems in practice assume a Kronecker model where the variances of the channel entries, upon decomposition on to the transmit and the receive eigen-bases, admit a separable form. Measurement campaigns, however, show that the Kronecker model results in poor estimates for capacity. Motivated by these observations, a channel model that does not impose a separable structure has been recently proposed and shown to fit the capacity of measured channels better. In this work, we show that this recently proposed modeling framework can be viewed as a natural consequence of channel decomposition on to its canonical coordinates, the transmit and/or the receive eigen-bases. Using tools from random matrix theory, we then establish the theoretical basis behind the Kronecker mismatch at the low- and the high-SNR extremes: 1) Sparsity of the dominant statistical degrees of freedom (DoF) in the true channel at the low-SNR extreme, and 2) Non-regularity of the sparsity structure (disparities in the distribution of the DoF across the rows and the columns) at the high-SNR extreme.Comment: 39 pages, 5 figures, under review with IEEE Trans. Inform. Theor

The use of information technology and computer mediated communication systems in a downsized corporation

Information technology and computer mediated communication system usage was measured in a large, technology driven downsized corporate division. Specific interest was given to the ways in which current computer usage may differ from reviews written in the 1980s. Our results suggest that, though some similarities exist between the earlier reviews and our survey, differences in IT usage also exist. Additionally, we found the inclusion of CMCS questions in our measure significantly changed the degree to which computers are used by all levels and departments within an organization. Reasons for the similarities and differences in our descriptions of computer usage in the 1980s and the 1990s are discussed

Effect of Layer Thickness on Structural, Morphological and Superconducting Properties of Nb\u3csub\u3e3\u3c/sub\u3eSn Films Fabricated by Multilayer Sequential Sputtering

Superconducting Nb3Sn films can be synthesized by controlling the atomic concentration of Sn. Multilayer sequential sputtering of Nb and Sn thin films followed by high temperature annealing is considered as a method to fabricate Nb3Sn films, where the Sn composition of the deposited films can be controlled by the thickness of alternating Nb and Sn layers. We report on the structural, morphological and superconducting properties of Nb3Sn films fabricated by multilayer sequential sputtering of Nb and Sn films on sapphire substrates followed by annealing at 950 °C for 3 h. We have investigated the effect of Nb and Sn layer thickness and Nb:Sn ratio on the properties of the Nb3Sn films. The crystal structure, surface morphology, surface topography, and film composition were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and energy dispersive X-ray spectroscopy (EDS). The results showed Sn loss from the surface due to evaporation during annealing. Superconducting Nb3Sn films of critical temperature up to 17.93 K were fabricated

Is Femur Length the Key Height Component in Risk Prediction of Type 2 Diabetes Among Adults?

OBJECTIVE — To examine the diabetes risk association with femur length, standing height, and height without femur length (HWFL) (HWFL standing height femur length). RESEARCHDESIGNANDMETHODS — We used data from three time periods of the National Health and Nutrition Examination Survey (1999–2000, 2001–2002, and 2003–2004) for this cross-sectional analysis and confined the eligible subjects to 6,188 adults aged 20 years who had fasted8 h and had no missing values of femur length or standing height. The outcome measure was type 2 diabetes. RESULTS — Multivariate logistic regression analyses indicated that the odds of type 2 diabe-tes per 1-SD value increase in femur length, standing height, and HWFL were 0.73 (95 % CI 0.61–0.86), 0.91 (0.75–1.10), and 1.09 (0.90–1.32) for men, respectively, and 0.82 (0.70– 0.97), 0.99 (0.82–1.21), and 1.11 (0.93–1.33) for women. CONCLUSIONS — Our study supports the hypothesis that femur length may be the key height component in diabetes risk association. Diabetes Care 32:739–740, 2009 Anumber of studies have observedthat adult height is negatively asso-ciated with the risk of glucose intol

Diagnostic accuracy of computed tomography scan in renal cell carcinoma

Background: Renal cell carcinoma (RCC) is becoming more common over the world. At the same time, numerous European and North American countries have achieved lower death rates. Methods: This cross-sectional observational study was conducted from July 2013 to June 2014 in the department of radiology and imaging of Dhaka Medical College Hospital. Clinically suspected 50 cases of renal cell carcinoma were included in this study. The study taken ethical clearance from the department and consent from the respondents. Statistical package for the social sciences (SPSS) software used for the analysis. Results: The mean age of the patients was 50.08±13.04 years. Male to female ratio was 2.1. More than half of the cases had hypodense lesion while 28% patients had calcification in the lesion. Mild enhancement was found in 56% cases and 50% were heterogenous in nature. Both nodal involvement and metastasis were limited. Computed tomography (CT) scan had 97.73% sensitivity and 100% specificity in diagnosis RCC. The diagnostic accuracy, positive predicative value and negative predicative values were 98%, 100% and 85.7 respectively. Conclusions: CT scan is a useful diagnostic modality in diagnosis of renal cell carcinoma

AUTO-CDD: automatic cleaning dirty data using machine learning techniques

Cleaning the dirty data has become very critical significance for many years, especially in medical sectors. This is the reason behind widening research in this sector. To initiate the research, a comparison between currently used functions of handling missing values and Auto-CDD is presented. The developed system will guarantee to overcome processing unwanted outcomes in data Analytical process; second, it will improve overall data processing. Our motivation is to create an intelligent tool that will automatically predict the missing data. Starting with feature selection using Random Forest Gini Index values. Then by using three Machine Learning Paradigm trained model was developed and evaluated by two datasets from UCI (i.e. Diabetics and Student Performance). Evaluated outcomes of accuracy proved Random Forest Classifier and Logistic Regression gives constant accuracy at around 90%. Finally, it concludes that this process will help to get clean data for further analytical process

Distinctive Responsiveness to Stromal Signaling Accompanies Histologic Grade Programming of Cancer Cells

Whether stromal components facilitate growth, invasion, and dissemination of cancer cells or suppress neoplastic lesions from further malignant progression is a continuing conundrum in tumor biology. Conceptualizing a dynamic picture of tumorigenesis is complicated by inter-individual heterogeneity. In the post genomic era, unraveling such complexity remains a challenge for the cancer biologist. Towards establishing a functional association between cellular crosstalk and differential cancer aggressiveness, we identified a signature of malignant breast epithelial response to stromal signaling. Proximity to fibroblasts resulted in gene transcript alterations of >2-fold for 107 probes, collectively designated as Fibroblast Triggered Gene Expression in Tumor (FTExT). The hazard ratio predicted by the FTExT classifier for distant relapse in patients with intermediate and high grade breast tumors was significant compared to routine clinical variables (dataset 1, n = 258, HR – 2.11, 95% CI 1.17–3.80, p-value 0.01; dataset 2, n = 171, HR - 3.07, 95% CI 1.21–7.83, p-value 0.01). Biofunctions represented by FTExT included inflammatory signaling, free radical scavenging, cell death, and cell proliferation. Unlike genes of the ‘proliferation cluster’, which are overexpressed in aggressive primary tumors, FTExT genes were uniquely repressed in such cases. As proof of concept for our correlative findings, which link stromal-epithelial crosstalk and tumor behavior, we show a distinctive differential in stromal impact on prognosis-defining functional endpoints of cell cycle progression, and resistance to therapy-induced growth arrest and apoptosis in low vs. high grade cancer cells. Our experimental data thus reveal aspects of ‘paracrine cooperativity’ that are exclusively contingent upon the histopathologically defined grade of interacting tumor epithelium, and demonstrate that epithelial responsiveness to the tumor microenvironment is a deterministic factor underlying clinical outcome. In this light, early attenuation of epithelial-stromal crosstalk could improve the management of cases prone to be clinically challenging