Watermarking security

International audienceThis chapter deals with applications where watermarking is a security primitive included in a larger system protecting the value of multimedia content. In this context, there might exist dishonest users, in the sequel so-called attackers, willing to read/overwrite hidden messages or simply to remove the watermark signal.The goal of this section is to play the role of the attacker. We analyze means to deduce information about the watermarking technique that will later ease the forgery of attacked copies. This chapter first proposes a topology of the threats in Section 6.1, introducing three different concepts: robustness, worst-case attacks, and security. Previous chapter has already discussed watermark robustness. We focus on worst-case attacks in Section 6.2, on the way to measure watermarking security in Section 6.3, and on the classical tools to break a watermarking scheme in Section 6.4. This tour of watermarking security concludes by a summary of what we know and still do not know about it (Section 6.5) and a review of oracle attacks (Section 6.6). Last, Section 6.7 deals with protocol attacks, a notion which underlines the illusion of security that a watermarking primitive might bring when not properly used in some applications

Environmental impact of passenger ships in port

The environmental impact of ships can be of different types. This thesis covers air pollution due to chemicals and concentrates on local effects due to compounds emitted in the exhaust gases of internal combustion engines and acoustic pollution. The attention has been focused on the consequences of the presence of many ships in ports located close to inhabited zones. For port-scale analyzes, the case study is the port of Naples for which traffics, geographic conformation, meteorological conditions, results of experimental campaigns both in the field of acoustic and environmental impact are available. In the field of polluting emissions, the case study for the simulations is a catamaran in service at the port of Naples for which experimental measurements at sea and bench tests are available. For the simulation of acoustic emissions, the case study is a passenger ship for which experimental measurements and forecast data are available. Experimental campaigns and simulations have been carried out on the port of Naples and most of the applications concern passenger ships, but methods and procedures can be applied to a general case. The thesis consists of six chapters, briefly introduced here. Each chapter contains a first subsection named "aims and scope" precisely to describe its main purposes in a more extended way than the summary presented here. The theme is first framed in the more general context of the environmental impact of anthropogenic activities and of marine transportation in particular assessment studies and documents issued by international bodies reporting targets for limiting the global environmental impact of the shipping sector are briefly summarized. Recalls on the main mechanisms of formation and reduction of pollutants are exposed. The second chapter describes the bottom-up method aimed at estimating the emissions of passenger ships in port. To obtain an estimation of all the emissions a series of very specific steps are necessary. The main information to be collected and produced concerns: traffic, routes, arrival and departure schedules, engine loads, emissions, heights, and diameters of the funnels. The technique of data collection and its use was gradually deepened (from simple cruise calendar to AIS data). The main application on the entire port sees the use of AIS data. The starting AIS data have been processed through an "ad hoc" MATLAB code capable of managing a relevant amount of data and returning a complete calendar of all the movements of every ship arriving and operating in the port. The use of AIS data has brought about improvements in the calculation methodology for emissions as well, allowing for example a more accurate analysis of average speeds in port and idle times. The port of Naples, where all the analysis were developed, is presented next. The traffics for the years and reference periods chosen in the subsequent analyzes are presented (2012, 2016, and 2018). A comprehensive study of the environmental impact of ships cannot be separated from the creation of atmospheric dispersion models. These models require the flow of pollutants emitted in the main operational phases in port (navigation, maneuvering, and mooring) as the main inputs. The results allow to estimate the weight that the passenger branch has on air quality also thanks to cross-comparisons with port measurements and ARPAC (Regional Agency for Environmental Protection in Campania) data. After the analysis of the environmen0tal impact on a port scale, the problem of emissions has been approached by applying a designated simulation, with the aim to overcome the use of emission factors. The first part of the chapter describes a state of the art of simulation model and an in-depth analysis of the main emission simulation methodologies. An engine model has been created in RICARDO WAVE environment; this engine model was validated and calibrated on an engine installed onboard a passenger ship operating in the port of Naples. Bench test results in terms of power, torque, consumption, and rpm have been used to calibrate the model while experimental measurements validated it. In the dissertation, a description of the case study (ship, engine, bench tests, and sea trials), a description of the model, and an interpretation of the results are presented. The validation on sea trials shows the effectiveness of the model both in terms of main engine parameters and emissions. At the end of the chapter, a comparison between the three emission estimation methodologies (EMEP-EEA, with AIS data, simulations, and experimental campaign) has been carried out. The next chapter of the thesis concerns the assessment of the acoustic impact of passenger ships in port. The structure of the research is typically the same: simulation and experimental results. The first part shows some experimental surveys made on a passenger ship in port that served as validation of a simulation model built in the TERRAIN OLIVE TREE LAB SUITE environment. The second and last part presents the methodology and results obtained in the context of a collaborative research project between the Universities of Naples, Genoa, and Trieste. The project aimed at characterizing the acoustic impact of a ship in light of the new additional class notation published by the Lloyds Register "Procedure for the Determination of Airborne Noise Emissions from Marine Vessels Airborne Noise Emissions from Marine Vessels". The last chapter sets out three applications in order to keep the problem set in a global scale context. The first presents an analysis of the possible countermeasures that can be applied to the cruise ship fleet aimed at environmental safeguarding (DNV Appraisal Tool), in the wake of the EEOI and EEDI. Furthermore, in the context of the environmental impact on a port scale, preliminary measurements of polluting emissions using remote measurement instruments (LIDAR) were carried out with the aim of allowing an indirect estimate of the concentrations of pollutants in the exhausts of ships, thus significantly reducing the uncertainties related to ground-level measurements with active or passive samplers. The last application, on the other hand, concerns the ports and the possible activities and initiatives to be implemented in order to host fleet of increasingly green and eco-sustainable ships (Environmental Ship Index)