Performance evaluation of a Wi-Fi-based multi-node network for distributed audio-visual sensors

The experimental research described in this manuscript proposes a complete network system for distributed multimedia acquisition by mobile remote nodes, streaming to a central unit, and centralized real-time processing of the collected signals. Particular attention is placed on the hardware structure of the system and on the research of the best network performances for an efficient and secure streaming. Specifically, these acoustic and video sensors, microphone arrays and video cameras respectively, can be employed in any robotic vehicles and systems, both mobile and fixed. The main objective is to intercept unidentified sources, like any kind of vehicles or robotic vehicles, drones, or people whose identity is not a-priory known whose instantaneous location and trajectory are also unknown. The proposed multimedia network infrastructure is analysed and studied in terms of efficiency and robustness, and experiments are conducted on the field to validate it. The hardware and software components of the system were developed using suitable technologies and multimedia transmission protocols to meet the requirements and constraints of computation performance, energy efficiency, and data transmission security

Heads will roll! Routes to effective trust repair in the aftermath of a CEO transgression

CEO transgressions are a common storyline in today's business press. Such incidents result in the need to repair trust for both the CEO and the organisation that the CEO leads. Existing empirical research on trust repair has focused primarily on interpersonal trust, resulting in a body of knowledge that provides many insights to the errant CEO but few insights for those who aim to repair trust in the organisation. Since organisations also need to regain the trust of stakeholders after a CEO transgression, research on organisational trust repair is clearly warranted. Organisations have options for trust repair that are not available to individuals (e.g. dismissing the transgressor), these actions may be initiated by parties other than the culpable party (e.g. the Board of Directors), and the mechanisms underlying organisational versus interpersonal trust repair may differ. However, trust in CEOs and their associated organisations may also be intertwined since the CEO is the symbolic representative of the organisation. To better understand how organisations and CEOs can repair trust in the aftermath of a CEO transgression, we conduct a scenario experiment examining two tactics that are commonly used in practice: CEO dismissal, and CEO apology + penance. We also examine the proposed underlying mechanisms of perceived repentance and perceived disentitativity. Results indicate that both tactics can influence trust in the CEO as well as the organisation, and that perceived repentance and perceived disentitativity mediate the effects of Board responses on trust in the CEO but not on trust in the organisation

Distribution of the coal flow in the mill-duct system of the As Pontes Power Plant using CFD modeling

The efficiency of a Power Plant is affected by the distribution of the pulverized coal within the furnace. The coal, which is pulverized in the mills, is transported and distributed by the primary gas through the mill-ducts to the interior of the furnace. This is done with a double function: dry and enter the coal by different levels for optimizing the combustion in the sense that a complete combustion occurs with homogeneous heat fluxes to the walls. The mill-duct systems of a real Power Plant are very complex and they are not yet well understood. In particular, experimental data concerning the mass flows of coal to the different levels are very difficult to measure. CFD modeling can help to determine them. An Eulerian/Lagrangian approach is used due to the low solid–gas volume ratio

The Diverse Solar Phase Curves of Distant Icy Bodies. II. The Cause of the Opposition Surges and Their Correlations

We collect well-measured opposition surge properties for many icy bodies orbiting the Sun (mostly from our own observations) plus for many icy moons, resulting in a data base of surface and orbital properties for 52 icy bodies. (1) We put forward four criteria for determining whether the surge is being dominated by shadow hiding (SH) or coherent backscattering (CB) based on readily measured quantities. The CB surge mechanism dominates if the surge is color dependent, the phase curve is steeper than 0.04 mag/deg, the phase curve shape matches the CB model of Hapke, or if the albedo is higher than roughly 40%. (2) We find that virtually all of our sample have their phase curves dominated by CB at low phase angles. (3) We present a graphical method to determine the Hapke surge parameters B_C0 and h_C. (4) The Kuiper Belt Objects (KBOs) and Centaurs have relatively high surge amplitudes, B_C0 > ~0.5 and widths with h_C ~ 3 deg. (5) We find highly significant but loose correlations between surge properties and the colors, albedos, and inclinations. We interpret this as young surfaces tending to have low surge slopes, high albedo, and gray colors. (6) Nereid has its surface properties similar to other icy moons and greatly different from KBOs and Centaurs, so we conclude that Nereid is likely a nearly-ejected inner Neptunian moon rather than a captured KBO.Comment: Astronomical Journal, in press, 41 pages, 5 figure