On rank estimation in semidefinite matrices

This work concerns the problem of rank estimation in semidefinite matrices, having either indefinite or semidefinite matrix estimator satisfying a typical asymptotic normality condition. Several rank tests are examined, based on either available rank tests or basic new results. A number of related issues are discussed such as the choice of matrix estimators and rank tests based on finer assumptions than those of asymptotic normality of matrix estimators. Several examples where rank estimation in semidefinite matrices is of interest are studied and serve as guide throughout the work.rank, symmetric matrix, indefinite and semidefinite estimators, eigenvalues, matrix decompositions, estimation, asymptotic normality.

Local and global rank tests for multivariate varying-coefficient models

In a multivariate varying-coefficient model, the response vectors Y are regressed on known functions u(X) of some explanatory variables X and the coefficients in an unknown regression matrix q(Z) depend on another set of explanatory variables Z. We provide statistical tests, called local and global rank tests, which allow to estimate the rank of an unknown regression coefficient matrix q(Z) locally at a fixed level of the variable Z or globally as the maximum rank over all levels of Z, respectively. In the case of local rank tests, we do so by applying already available rank tests to a kernel-based estimator of the coefficient matrix q(z). Global rank tests are obtained by integrating test statistics used in estimation of local rank tests. We present a simulation study where, focusing on global ranks, we examine small sample properties of the considered statistical tests. We also apply our results to estimate the so-called local and global ranks in a demand system where budget shares are regressed on known functions of total expenditures and the coefficients in a regression matrix depend on prices faced by a consumer.varying-coefficient model, kernel smoothing, matrix rank estimation, demand systems, local and global ranks

Boardroom Cultural Governance: An Examination of the Beliefs and Values of Board Directors and Executive Management in U.S. Based Multinational Corporations (MNCs)

In the evolving global economy, boardroom governance has forged an increasing influence on what transpires in corporations today. Within the boardroom, expectations of board directors and executive management (key actors) have shifted dramatically due to the financial failures (i.e., Enron and WorldCom, etc.) and the ensuing global financial crisis in the 2000s. The belief is that these directors and managers contributed greatly to these crises (Boerner, 2011). Consequently, there is a growing appeal to study boardroom governance and the roles of board directors and executive managers, not from a structural description, but rather from a behavioral perspective. In the literature, corporate governance structural framework is well informed while the behavioral framework is lacking. Often referred to as a black box, board behavior is not well understood because board processes are not easily observed nor are researchers readily invited to do so (Barratt & Korac-Kakabadse, 2002). There is therefore a clear call for studies to examine the black box of boardroom governance (Erakovic & Overall, 2010; Lockhart, 2010; Huse et al, 2011). Recognizing this demand, an examination of the beliefs and values of the board directors and executive managers in their boardroom culture, was undertaken as the starting point to open the black box of boardroom governance

Sanitser, an innovative sanitary ware body, formulated with waste glass and recycled materials

Abstract In the present paper, the results of "Sanitser" Life European project are presented. The aim of this study was to reduce the firing temperature for ceramic body (from 1250 to 1170 °C). This was achieved substituting feldspar and quartz with recycled blend materials and a little percentage of flux (less than 3%); in a sanitary ware vitreous china formulation a waste glass, granitic materials and fired broken ceramic pieces were introduced. Tests performed on the Sanitser formulation showed that it has the same final physical-chemical characteristics of the industrial vitreous china (VC) body. Besides, different ceramic pieces (wash basin, bidet and WC pan) were compared with VC production. The results showed that Sanitser body can replace vitreous china in the sanitary ware production. In this project, the firing temperature of the ceramic body is reduced significantly with a supposed decrease of the CO2 emissions. In Sanitser formulation, about 43.6% of recycled materials that would end in dumps were utilized

Final report of the EURISOL Design Study (2005-2009) A Design Study for a European Isotope-Separation-On-Line Radioactive Ion Beam Facility

European Commission Contract N°515768 RIDS Published by GANI

Machine learning for wireless link quality estimation: A survey

Since the emergence of wireless communication networks, a plethora of research papers focus their attention on the quality aspects of wireless links. The analysis of the rich body of existing literature on link quality estimation using models developed from data traces indicates that the techniques used for modeling link quality estimation are becoming increasingly sophisticated. A number of recent estimators leverage Machine Learning (ML) techniques that require a sophisticated design and development process, each of which has a great potential to significantly affect the overall model performance. In this article, we provide a comprehensive survey on link quality estimators developed from empirical data and then focus on the subset that use ML algorithms. We analyze ML-based Link Quality Estimation (LQE) models from two perspectives using performance data. Firstly, we focus on how they address quality requirements that are important from the perspective of the applications they serve. Secondly, we analyze how they approach the standard design steps commonly used in the ML community. Having analyzed the scientific body of the survey, we review existing open source datasets suitable for LQE research. Finally, we round up our survey with the lessons learned and design guidelines for ML-based LQE development and dataset collection

Learning to detect anomalous wireless links in IoT networks

After decades of research, Internet of Things (IoT) is finally permeating real-life and helps improve the efficiency of infrastructures and processes as well as our health. As massive number of IoT devices are deployed, they naturally incurs great operational costs to ensure intended operations. To effectively handle such intended operations in massive IoT networks, automatic detection of malfunctioning, namely anomaly detection, becomes a critical but challenging task. In this paper, motivated by a real-world experimental IoT deployment, we introduce four types of wireless network anomalies that are identified at the link layer. We study the performance of threshold- and machine learning (ML)-based classifiers to automatically detect these anomalies. We examine the relative performance of three supervised and three unsupervised ML techniques on both non-encoded and encoded (autoencoder) feature representations. Our results demonstrate that; i) selected supervised approaches are able to detect anomalies with F1 scores of above 0.98, while unsupervised ones are also capable of detecting the said anomalies with F1 scores of, on average, 0.90, and ii) OC-SVM outperforms all the other unsupervised ML approaches reaching at F1 scores of 0.99 for SuddenD, 0.95 for SuddenR, 0.93 for InstaD and 0.95 for SlowD

Dalle Province all’area vasta: un’incoerenza italiana

La storia della delimitazione regionale in Italia ci aiuta a capire quanto artificiale possa essere la rappresentazione che di esse hanno i diversi governi regionali. In questo capitolo si procede a una comparazione con quella provinciale, ben più antica, che ci permetta anche di mostrarne il ruolo nella programmazione attuale.The history of regional borders in Italy cans show the artificial representation that their governments propose. For this reason the comparison with the provincial delimitations, older than the first, can help to explain why it is important a deeper reflection about the question to renounce to this institutional level