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The diesel generators are usually used for supplying the electrical demand of the semi-submersible oil drilling rigs. The specific fuel consumption (SFC) of each diesel engine changes nonlinearly with respect to its power product. Hence, this paper presents an economic fuel dispatch model for diesel engines powered oil rig platforms using the cubic spline interpolation curve fitting of the SFC-power non-linear dependence. Moreover, the total fuel consumption of the diesel generators significantly reduces by shifting a partial part of the electricity demand of the offshore drilling rigs from on-peak time intervals to off-peak periods. In addition, battery energy storage contributes to the load curve smoothing strategy. A mixed-integer non-linear programming problem is developed under generalized algebraic mathematical modeling system to find the optimum fuel consumption and power generation schedules of the diesel producers, the value of demand increase/decrease, and the charge/discharge pattern of the battery at each operating time interval. A benchmark oil rig with eight diesel engines and four tidal turbines is considered to validate the proposed methodology. Four cases are studied without and with application of battery and load shifting program. It is found that implementation of peak-clipping and valley filling to energy demand pattern and battery integration with tidal-diesel driven oil rigs cause a significant fuel saving. In the presence of battery, 70 g fuel saving is achieved over a 24-hours study horizon. Moreover, the implementation of time-based load shifting program with the capability of 30% load decreasing (at peak hours) and increasing (at off-peak periods) makes it possible to save 282 g diesel fuel according to the base electrical demand profile. Finally, simultaneous integration of battery and demand-side management programs (with maximum 10% load flexibility) causes 216 g fuel saving in sample operation day.

Platform Supply Vessel – PSV and Anchor Handling Tug Supply Vessels – AHTS purpose is delivering various equipment from shore bases facilities to oilfields/platforms. Supply and demand for PSV and AHTS fleet depends on world’s consumption energy. Fossil fuels (oil & gas) make one of the most important energy source in word energy production. Although future trends shows that the dependence on oil and gas as energy source will decrease, oil and gas remain a major source of consumption representing more than 50% of market share. The PSV market is highly cyclical. Utilisation and rates highly correlated to oil price. Volatility between supply and demand for those ships is what causes the low daily/monthly rates of these ship. Main cause is small number of active platforms and a large number of PSV & AHTS. The daily/monthly rates felt below operating cost of the ships. The value of the market for ships supplying oil fields and platforms was $ 20.06 billion in 2018. Projection is that market could reach amount of $ 25.66 billion by 2023. This paper focus on the market for platform supply ships and the number of crew working on board these vessels. Further, oil price trends and the impact of that price on the offshore industry will be analysed.

We firstly present in this thesis the permutation Bootstrap method applied for the block maxima (BM) method in extreme value theory. The method is based on BM ranks whose distribution is presented and simulated. It performs well and leads to a variance reduction in the estimation of the GEV parameters and the extreme quantiles. Secondly, we build upon the heteroscedastic extremes framework by Einmahl et al. (2016) where the observations are assumed independent but not identically distributed and the variation in their tail distributions is modeled by the so-called skedasis function. While the original paper focuses on non-parametric estimation of the skedasis function, we consider here parametric models and prove the consistency and asymptotic normality of the parameter estimators. A parametric test for trend detection in the case where the skedasis function is monotone is introduced. A short simulation study shows that the parametric test can be more powerful than the non-parametric Kolmogorov-Smirnov type test, even for misspecified models. We also discuss the choice of threshold based on Lepski's method. The methodology is finally illustrated on a dataset of minimal/maximal daily temperatures in Fort Collins, Colorado, during the 20th century. Thirdly, we have a training sample data of daily maxima precipitation over 24 years in 40 stations. We make spatio-temporal prediction of quantile of level corresponding to extreme monthly precipitation over the next 20 years in every station. We use generalized extreme value models by incorporating covariates. After selecting the best model based on the Akaike information criterion and the k-fold cross validation method, we present the results of the estimated quantiles for the selected models. Finally, we study the wind speed and wave height risks in Beddawi region in the northern Lebanon during the winter season in order to protect the oil rig that will be installed. We estimate the return levels associated to return periods of 50, 100 and 500 years for each risk separately using the univariate extreme value theory. Then, by using the multivariate extreme value theory we estimate the dependence between extreme wind speed and wave height as well as joint exceedance probabilities and joint return levels to take into consideration the risk of these two environmental factors simultaneously.; Nous présentons dans cette thèse en premier lieu la méthode de Bootstrap par permutation appliquée à la méthode des blocs maxima utilisée en théorie des valeurs extrêmes (TVE) univariée. La méthode est basée sur un échantillonnage particulier des données en utilisant les rangs des blocs maxima dont la distribution est présentée et introduite dans les simulations. Elle amène à une réduction de la variance des paramètres de la loi GEV et des quantiles estimés. En second lieu, on s’intéresse au cas où les observations sont indépendantes mais non identiquement distribuées en TVE. Cette variation dans la distribution est quantifiée en utilisant une fonction dite « skedasis function » notée c qui représente la fréquence des extrêmes. Ce modèle a été introduit par Einmahl et al. dans le papier « Statistics of heteroscedastic extremes ». On étudie plusieurs modèles paramétriques pour c (log-linéaire, linéaire, log-linéaire discret) ainsi que les résultats de consistance et de normalité asymptotique du paramètre θ représentant la tendance. Le test θ =0 contre θ ≠0 est interprété alors comme un test de détection de tendance dans les extrêmes. Nous illustrons nos résultats dans une étude par simulation qui montre en particulier que les tests paramétriques sont en général plus puissants que les tests non paramétriques pour la détection de la tendance, d’où l’utilité de notre travail. Nous discutons en plus le choix du seuil k en appliquant la méthode de Lepski. Enfin, nous appliquons la méthodologie sur les données de températures minimales et maximales dans la région de Fort Collins, Colorado durant le 20ème siècle afin de détecter la présence d’une tendance dans les extrêmes sur cette période. En troisième lieu, on dispose d’un jeu de données de précipitation journalière maximale sur 24 ans dans 40 stations. On réalise une prédiction spatio-temporelle des quantiles correspondants à un niveau de retour de 20 ans pour les précipitations mensuelles dans chaque station. Nous utilisons des modèles de GEV en introduisant des covariables dans les paramètres. Le meilleur modèle est choisi en termes d’AIC et par la méthode de validation croisée. Pour chacun des deux modèles choisis, nous estimons les quantiles extrêmes. Finalement, on applique la TVE unvariée et bivariée sur les vitesses du vent et la hauteur des vagues dans une région au Liban en vue de protéger la plateforme pétrolière qui y sera installée de ces risques environnementaux. On applique d’abord la théorie univariée sur la vitesse du vent et la hauteur des vagues séparément en utilisant la méthode des blocs maximas pour estimer les paramètres de la GEV et les niveaux de retour associés à des périodes de retour de 50, 100 et 500 années. Nous passons ensuite à l’application de la théorie bivariée afin d’estimer la dépendance entre les vents et les vagues extrêmes et d’estimer des probabilités jointes de dépassement des niveaux de retour univariés. Nous associons ces probabilités jointes de dépassement à des périodes de retour jointes et nous les comparons aux périodes de retour marginales.

We firstly present in this thesis the permutation Bootstrap method applied for the block maxima (BM) method in extreme value theory. The method is based on BM ranks whose distribution is presented and simulated. It performs well and leads to a variance reduction in the estimation of the GEV parameters and the extreme quantiles. Secondly, we build upon the heteroscedastic extremes framework by Einmahl et al. (2016) where the observations are assumed independent but not identically distributed and the variation in their tail distributions is modeled by the so-called skedasis function. While the original paper focuses on non-parametric estimation of the skedasis function, we consider here parametric models and prove the consistency and asymptotic normality of the parameter estimators. A parametric test for trend detection in the case where the skedasis function is monotone is introduced. A short simulation study shows that the parametric test can be more powerful than the non-parametric Kolmogorov-Smirnov type test, even for misspecified models. We also discuss the choice of threshold based on Lepski's method. The methodology is finally illustrated on a dataset of minimal/maximal daily temperatures in Fort Collins, Colorado, during the 20th century. Thirdly, we have a training sample data of daily maxima precipitation over 24 years in 40 stations. We make spatio-temporal prediction of quantile of level corresponding to extreme monthly precipitation over the next 20 years in every station. We use generalized extreme value models by incorporating covariates. After selecting the best model based on the Akaike information criterion and the k-fold cross validation method, we present the results of the estimated quantiles for the selected models. Finally, we study the wind speed and wave height risks in Beddawi region in the northern Lebanon during the winter season in order to protect the oil rig that will be installed. We estimate the return levels associated to return periods of 50, 100 and 500 years for each risk separately using the univariate extreme value theory. Then, by using the multivariate extreme value theory we estimate the dependence between extreme wind speed and wave height as well as joint exceedance probabilities and joint return levels to take into consideration the risk of these two environmental factors simultaneously., Nous présentons dans cette thèse en premier lieu la méthode de Bootstrap par permutation appliquée à la méthode des blocs maxima utilisée en théorie des valeurs extrêmes (TVE) univariée. La méthode est basée sur un échantillonnage particulier des données en utilisant les rangs des blocs maxima dont la distribution est présentée et introduite dans les simulations. Elle amène à une réduction de la variance des paramètres de la loi GEV et des quantiles estimés. En second lieu, on s’intéresse au cas où les observations sont indépendantes mais non identiquement distribuées en TVE. Cette variation dans la distribution est quantifiée en utilisant une fonction dite « skedasis function » notée c qui représente la fréquence des extrêmes. Ce modèle a été introduit par Einmahl et al. dans le papier « Statistics of heteroscedastic extremes ». On étudie plusieurs modèles paramétriques pour c (log-linéaire, linéaire, log-linéaire discret) ainsi que les résultats de consistance et de normalité asymptotique du paramètre θ représentant la tendance. Le test θ =0 contre θ ≠0 est interprété alors comme un test de détection de tendance dans les extrêmes. Nous illustrons nos résultats dans une étude par simulation qui montre en particulier que les tests paramétriques sont en général plus puissants que les tests non paramétriques pour la détection de la tendance, d’où l’utilité de notre travail. Nous discutons en plus le choix du seuil k en appliquant la méthode de Lepski. Enfin, nous appliquons la méthodologie sur les données de températures minimales et maximales dans la région de Fort Collins, Colorado durant le 20ème siècle afin de détecter la présence d’une tendance dans les extrêmes sur cette période. En troisième lieu, on dispose d’un jeu de données de précipitation journalière maximale sur 24 ans dans 40 stations. On réalise une prédiction spatio-temporelle des quantiles correspondants à un niveau de retour de 20 ans pour les précipitations mensuelles dans chaque station. Nous utilisons des modèles de GEV en introduisant des covariables dans les paramètres. Le meilleur modèle est choisi en termes d’AIC et par la méthode de validation croisée. Pour chacun des deux modèles choisis, nous estimons les quantiles extrêmes. Finalement, on applique la TVE unvariée et bivariée sur les vitesses du vent et la hauteur des vagues dans une région au Liban en vue de protéger la plateforme pétrolière qui y sera installée de ces risques environnementaux. On applique d’abord la théorie univariée sur la vitesse du vent et la hauteur des vagues séparément en utilisant la méthode des blocs maximas pour estimer les paramètres de la GEV et les niveaux de retour associés à des périodes de retour de 50, 100 et 500 années. Nous passons ensuite à l’application de la théorie bivariée afin d’estimer la dépendance entre les vents et les vagues extrêmes et d’estimer des probabilités jointes de dépassement des niveaux de retour univariés. Nous associons ces probabilités jointes de dépassement à des périodes de retour jointes et nous les comparons aux périodes de retour marginales.

This paper aims to explore the coordination among China’s various maritime actors in the South China Sea (SCS). Since around 2009, China has reinforced its maritime territorial claims in the SCS and has taken coercive measures, including harassing other countries’ vessels and using administrative tools to expand its effective control over disputed islands. One important question is whether China’s tactics are based on a well-coordinated plan or are the unintended consequence of competition and self-interest among the various agencies. This paper shows that, firstly, organisational coordination between these agencies is improving, secondly, that the PLA has a salient role in the operation, and lastly, that the long term trend is important. The paper implies that long-term aspirations are coalescing into more concrete plans under the strong leadership of Xi Jinping.

The topic concerning the legal status and regime of offshore oil platforms and rigs is still an important and unsolved issue since the development of this kind of crafts. The question arises from the absence – at the international level, but in certain cases also in the domestic law – of a uniform and exhaustive regime specific for these crafts that show a great variety of structures and purposes. It is interesting to note that, especially after the Deepwater Horizon disaster, only regional uniform rules, but not international uniform conventions, have been enacted in order to specifically address the issue of oil spill from offshore platforms and rigs. Some domestic legal systems assimilate oil rigs to ships for the enforcement of the provisions on the protection of the marine environment and the penalties for its pollution. Moreover, they could be engaged in severalactivities, such as exploration/research/measurement, drilling, production of oil, processing/treatment, storage or loading: while performing the different activities the oil rig is subject to the specific regime provided for each activity by the international law and the relevant domestic law. Their regime depends also on the place where they are located, together with their status as ships or other crafts: for example, under the Law of the Sea, when they are in the Territorial Sea, in the Contiguous Zone, in the Exclusive Economic Zone and/or on the Continental Shelf of a State, if they are considered as ships they fall within the jurisdiction of the flag State for activities other than the economic activities and marine scientific research there performed and with the exclusion of the protection and preservation of the marine environment that belong to the jurisdiction of the coastal State, whereas if they are deemed to be installations they fall in the latter’s jurisdiction with different consequences depending on the zone where they aresituated. Being destined to perform their activities in oceans or seasand to travel in these environmentsfor this purpose, they are also subject – at different levels, depending on their actual structures and activities – to the perils of the sea like ships: one of the main current issues concerning these structures is still the possibility to qualify them or some of them as ships or to apply to them their regime. Notwithstanding that this question is not new, no uniform satisfying solution has been reached yet: only for specific subject-mattersoil platforms and rigs or certain types of them have been expressly included in the scope of some international conventions or domestic law or have been equalized to ships or to fixed installations by them, leading to a fragmentary framework. It has already been efficaciously evidenced by distinguished scholars that a uniform and clear definition of the very object and means of carriage in Maritime Law – i.e. the ‘ship’ – still lacks, notwithstanding shipping’s millenary development, too( ): whereas in the past it was a more self-evident concept( ), the technical evolution of this means of transport has increased its complexity. The main difficulties arise not only from the evolution of ships or nautical structures from a technical point of view, with the development of means and structures with very different purposes and features (including oil platforms and rigs), but also from the complexity of a ‘ship’ from the legal perspective. Italian scholars have displayed it with the terms «juridical pluri-qualification» of this unique entity, but this view is also by other international Authors: from a static point of view, she is a good which is relevant under an economic and legal perspective; from a dynamic point of view, she is a registered movable property; she is also an organized system of persons and goods often destined to commercial activities; she is a vehicle; in Common Law, for example, she has legal personality; she is considered as a part of the territory of the flag State, etc. The above arguments are more over true with regard to oil platforms and rigs, due to the already described variety of structures, purposes and activities they can be engaged in. This article deals with a survey of the existing relevant international rules, a case study and a comparative analysis of the status of these structures in some domestic legal systems, in order to outline the existing criticalities and revise the possible solutions according also to contemporary challenges.