Impact of forcing errors in the CAMCAT oil spill forecasting system. A sensitivity study

The CAMCAT oil spill forecasting system is presented in this paper, and an evaluation of the impact of errors in the forcing fields over its forecasts is carried out. The system is formed by several independent modules which provide forecasts of winds, currents and waves to an oil spill module which predicts the evolution of the spill.The typical twin-experiments experience is used paying special attention to a realistic characterization of the errors when perturbing the forcing fields. The results suggest that errors in the wind and current fields are the main limiting factor for the quality of the oil spill forecasts. The pollutant identification is also crucial to determine the final vertical position and characteristics of the product.     

The impact of port choice on inland transportation

The Belgian government intends to shift part of its funding away from Antwerp and towards other seaports, particularly Ghent and Zeebrugge. In the long run, this policy change will undoubtedly influence the port choice and probably cause a traffic diversion at the expense of Antwerp. This will have a great influence on the structure of inland transportation.

The impact of port choice on inland transportation is the central theme of this paper. To this end a disaggregated model of the demand for freight transport is constructed.     

Calculating the return value using a mathematical model of significant wave height

This study presents a new method for calculating return values. The essence of the method is that it utilizes nonstationary data to calculate the return value for a region in the Northeast Pacific. The nonstationary data was obtained from a model which was previously developed for the behavior of the significant wave height as a function of time in the region. The method is illustrated by convolving two generalized Pareto distribution functions fitted to two parts of the model, computing a suitable extreme value from the new distribution function, and calculating the return value using this extreme value.     

Applying Human Systems Integration to the Rapid Acquisition Process

The rapidly changing complexity of the Global War on Terrorism has changed the approach to equipping forward-deployed military forces. Combatant Commanders conducting operations now require timely materiel solutions to enhance mission capabilities and reduce the risk for individual soldiers. To address this challenge, the US Army established the Rapid Equipping Force to assess emerging requirements, to propose solutions to those requirements, and to implement those solutions in an expedient time frame. Unfortunately, the REF lacks a consistent analytical methodology for assessing alternative materiel solutions. To address the need for a human systems integration (HSI) analysis method, the authors developed an Assessment-Based Rapid Acquisition HSI Analysis Method (ABRAHAM) capable of generating tailored surveys and evaluating these surveys for unacceptable risks to soldiers. To validate ABRAHAM's concept and content, ABRAHAM was showcased in three Department of Defense settings: the Human Factors Engineering Technical Advisory Group, the REF, and the US Marine Corps' Operational Test and Evaluation Activity. The ABRAHAM appears to fill a gap in the current library of HSI tools. Based on the feedback provided during the product showcases, there is sufficient interest and technological maturity to further develop ABRAHAM to serve both the traditional and rapid acquisition processes.     

A new marine propulsion system

A new marine propulsion system is proposed . A small liquid sodium cooled reactor acts as prime mover; alkali-metal thermal-to-electric conversion (AMTEC) cells are employed to convert the heat energy to electricity; superconducting magneto-hydrodynamic thruster combined with spray-water thruster works as propulsion. The configuration and characteristics of this system are described. Such a nuclear-powered propulsion system is not only free of noise, but also has high reliability and efficiency. It would be a preferable propulsion system for ships in the future。     

Determination of attainable regions in ship maneuvers: an application of differential inclusions to the modeling of ship dynamics

A commonly used mathematical tool in vehicle dynamics simulation is the ordinary differential equation. However, in some situations, these equations may not be sufficient to solve problems. For robust flight, surface ship or submarine control design, safety assessment, missile and aircraft guidance, the influence of disturbances, and differential games of pursuit–evasion, more versatile tools are needed. The differential inclusion (DI) is a generalization of a differential equation that can be extremely useful. The solution of a DI is not just a model trajectory or a set of trajectories obtained by a randomization of the original problem. The solution is a reachable set, and it is a deterministic object. A differential inclusion solver and its application to vessel movement are described. Compared to previous publications on the DI solver, the new feature is an implementation of the fuzzy sets technique to improve the resulting images. It is pointed out that the reachable sets cannot be assessed properly while treating the uncertain variables as random. The application of the DI solver can give a proper view of the regions in the state space where all the possible model trajectories belong.     

Novel Manufacturing Technology of Hyperbolic Plates for Shipbuilding

On the basis of the principle of dieless hydrobulging technology, a novel hydrobulging technology for manufacturinghyperbolic plates is proposed. First, a toroidal pipe elbow or a partial toroidal pipe elbow is formed, then the single hydrobulgedstructure can be cut up into some desired plates. It is proved by experiments and finite element simulation that manufacturingtechnology of hyperbolic plates adopting integrated hydrobulging forming technology is feasible.