An Efficient Approximate Algorithm for the k-th Selection Problem

We present an efficient randomized algorithm for the approximate k-th selection problem. It works in-place and it is fast and easy to implement. The running time is linear in the length of the input. For a large input set the algorithm returns, with high probability, an element which is very close to the exact k-th element. The quality of the approximation is analyzed theoretically and experimentally

Self-propagating reactions for environmental protection: Treatment of wastes containing asbestos

A thermochemical process based on the occurrence of self-propagating reactions that is able to convert asbestos fibers into harmless, nonfibrous species is proposed. Specifically, a mixture consisting of a waste (containing about 85 wt % of chrysotile), ferric oxide, and magnesium is able, once locally ignited by a thermal source, to generate a self-propagating reaction that travels through the mixture without requiring additional energy. The process is accompanied by a dramatic change in the material from both the chemical and microstructural points of view. In addition, front velocity and maximum combustion temperature decrease as the amount of waste in the starting mixture increases, with the self-propagating character being maintained if the waste content is equal to or below 60 wt %. It is also observed that, when nonasbestos (nontoxic) materials, i.e., sepiolite and glass fibers, are used instead of the hazardous waste, the front velocity, combustion temperature, propagation limits, and apparent activation energies are found to be very similar to those observed in the case of asbestos

The innovation potential of Islamic crowdfunding platforms in contributing to sustainable development

Purpose: This paper aims at explaining variances in the contribution of Islamic crowdfunding platforms (ICFPs) to sustainable development (SD), by adopting an institutional logic perspective (ILP). ICFPs represent a dual institutional overlap between two logics (the Western-mainstream and the Islamic logic) which have an impact on corporate social responsibility (CSR) interpretations, practices, and decisions and whose conflicts are mitigated by choosing different resolution strategies. The authors aim at showing that this choice affects SD differently. Design/methodology/approach: The authors develop a conceptual typology through the following steps: (1) choice of variables and identification of corresponding variable domains, through literature review. Variables chosen are the elemental CSR dimensions related to various social and environmental corporate responsibilities to whom diverse meaning and emphasis are given under the Western-mainstream and Islamic logics. (2) Identification of three distinct ideal types of ICFPs, building on different resolution strategies to mitigate conflicts between logics; (3) development, for each ideal type, of a set of implications related to SD; (4) implementation of a first test aiming at assigning real cases to each ideal type. Findings: The authors identify Western-mimicking (platforms adopting as resolution strategy decoupling or compartmentalizing strategies), Islamic-driven (platforms focusing on one prevailing logic) and Syncretism-inspired (platforms adopting hybridizing practices) ideal-types. Originality/value: It is the first paper suggesting ILP to explain variances in crowdfunding platforms' role in addressing SD. It focuses on a specific type of CF platforms till now neglected

Assessment of the economic and social impact using SROI: An application to sport companies

This paper evaluates the social impact of a football club and its philanthropic organization on the local community and its stakeholders, namely supporters, sponsors, players, and shopkeepers. The methodology used is the Social Return on Investment (SROI). SROI methodology includes all the beneficiaries that are beyond the scope of the company's accounting and its fiscal and financial statements. The aim is to assess both the benefits and the negative impacts of a company's activities on stakeholders. This type of analysis combines the use of qualitative, quantitative and financial information gathered and analyzes them in order to estimate the amount of "value", including mental health and well-being, created or destroyed by a business activity, by a project or by the overall operation of an organization. The sport club under review in the present analysis is called Virtus Entella, an Italian football club playing in the second division. An SROI indicator was applied in reference to the business activity that took place during the championship season 2017/2018. Results show that the social impact created during the championship amounts to approximately 44 million Euro against a financial investment of 15 million Euro, producing an SROI ratio of 2.98:1. This outcome suggests that for every euro invested by the football club, about 3 Euros of social value is created

Combustion synthesis of metal carbides: Part I. Model development

The definition of a rigorous theoretical framework for the appropriate physico-chemical description of self-propagating high-temperature synthesis (SHS) processes represents the main goal of this work which is presented in two sequential articles. In this article, a novel mathematical model to simulate SHS processes is proposed. By adopting a heterogeneous approach for the description of mass transfer phenomena, the model is based on appropriate mass and energy conservation equations for each phase present during the system evolution. In particular, it takes microstructural evolution into account using suitable population balances and properly evaluating the different driving forces from the relevant phase diagram. The occurrence of phase transitions is treated on the basis of the so-called enthalpy approach, while a conventional nucleation-and-growth mechanistic scenario is adopted to describe quantitatively the formation of reaction products. The proposed mathematical model may be applied to the case of combustion synthesis processes involving a low melting point reactant and a refractory one, as for the synthesis of transition metal carbides from pure metal and graphite. Thus, the model can be profitably used to gain a deeper insight into the microscopic elementary phenomena involved in combustion synthesis processes through a suitable combination of experimental and modeling investigations, as it may be seen in Part II of this wor

QuickHeapsort, an efficient mix of classical sorting algorithms

AbstractWe present an efficient and practical algorithm for the internal sorting problem. Our algorithm works in-place and, on the average, has a running-time of O(nlogn) in the size n of the input. More specifically, the algorithm performs nlogn+2.996n+o(n) comparisons and nlogn+2.645n+o(n) element moves on the average. An experimental comparison of our proposed algorithm with the most efficient variants of Quicksort and Heapsort is carried out and its results are discussed

Joint analysis of eye blinks and brain activity to investigate attentional demand during a visual search task

In several fields, the need for a joint analysis of brain activity and eye activity to investigate the association between brain mechanisms and manifest behavior has been felt. In this work, two levels of attentional demand, elicited through a conjunction search task, have been modelled in terms of eye blinks, brain activity, and brain network features. Moreover, the association between endogenous neural mechanisms underlying attentional demand and eye blinks, without imposing a time-locked structure to the analysis, has been investigated. The analysis revealed statistically significant spatial and spectral modulations of the recorded brain activity according to the different levels of attentional demand, and a significant reduction in the number of eye blinks when a higher amount of attentional investment was required. Besides, the integration of information coming from high-density electroencephalography (EEG), brain source localization, and connectivity estimation allowed us to merge spectral and causal information between brain areas, characterizing a comprehensive model of neurophysiological processes behind attentional demand. The analysis of the association between eye and brain-related parameters revealed a statistically significant high correlation (R > 0.7) of eye blink rate with anterofrontal brain activity at 8 Hz, centroparietal brain activity at 12 Hz, and a significant moderate correlation with the participation of right Intra Parietal Sulcus in alpha band (R = -0.62). Due to these findings, this work suggests the possibility of using eye blinks measured from one sensor placed on the forehead as an unobtrusive measure correlating with neural mechanisms underpinning attentional demand

An economic and financial exploratory

This paper describes the vision of a European Exploratory for economics and finance using an interdisciplinary consortium of economists, natural scientists, computer scientists and engineers, who will combine their expertise to address the enormous challenges of the 21st century. This Academic Public facility is intended for economic modelling, investigating all aspects of risk and stability, improving financial technology, and evaluating proposed regulatory and taxation changes. The European Exploratory for economics and finance will be constituted as a network of infrastructure, observatories, data repositories, services and facilities and will foster the creation of a new cross-disciplinary research community of social scientists, complexity scientists and computing (ICT) scientists to collaborate in investigating major issues in economics and finance. It is also considered a cradle for training and collaboration with the private sector to spur spin-offs and job creations in Europe in the finance and economic sectors. The Exploratory will allow Social Scientists and Regulators as well as Policy Makers and the private sector to conduct realistic investigations with real economic, financial and social data. The Exploratory will (i) continuously monitor and evaluate the status of the economies of countries in their various components, (ii) use, extend and develop a large variety of methods including data mining, process mining, computational and artificial intelligence and every other computer and complex science techniques coupled with economic theory and econometric, and (iii) provide the framework and infrastructure to perform what-if analysis, scenario evaluations and computational, laboratory, field and web experiments to inform decision makers and help develop innovative policy, market and regulation designs. Graphical abstrac

The Italian research project ROAD-NGN ‘Optical frequency/wavelength division multiple access techniques for next generation networks'

The paper describes the activities of the Italian national research project ROAD-NGN ‘Optical frequency/wavelength division multiple access techniques for next generation networks’; the project aims to investigate and experiment new technological solutions to facilitate the migration of access systems from copper to optical fibre, and to help the integration with broadband wireless architectures, with particular interest for the backhauling of the fourth generation (4G) Long Term Evolution (LTE) networks. The approaches, based on the orthogonal frequency division multiplexing (OFDM) and wavelength division multiplexing (WDM) techniques, can enable the unbundling of the local loop (ULL) and are upgradable toward very ultra wideband systems

Combustion synthesis of metal carbides: Part II. Numerical simulation and comparison with experimental data

Based on the general theoretical model proposed in Part I of this work [J. Mater. Res. 20, 1257 (2005)], a series of numerical simulations related to the self-propagating high-temperature synthesis in the Ti-C system is presented. A detailed and quantitative description of the various physical and chemical processes that take place during combustion synthesis processes is provided in Part II of this work. In particular, the proposed mathematical description of the system has been discussed by highlighting the relation between system macroscopic behavior obtained experimentally with the modeled phenomena taking place at the microscopic scale. Model reliability is tested by comparison with suitable experimental data being nucleation parameters adopted for the fitting procedure. The complex picture emerging as a result of the model sophistication indicates that the rate of conversion is essentially determined by the rate of nucleation and growth. In addition, comparison between model results and experimental data seems to confirm the occurrence of heterogeneous nucleation in product crystallization