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Two procedures are presented for validating track estimates obtained using the Maximum Likelihood Probabilistic Data Association (ML-PDA) algorithm. The ML-PDA developed for Very Low Observable (VLO) target tracking always provides a track estimate that must then be tested for target existence by comparing the value of the Log Likelihood Ratio (LLR) at the track estimate to a threshold. Using extreme value theory it is shown that in the absence of a target the LLR at the track estimate obeys approximately a Gumbel distribution rather than the Gaussian distribution previously ascribed to it in the literature. The off-line track validation procedure relies on extensive offline simulations to obtain a set of track validation thresholds. The real-time procedure uses the data set that produced the track estimate to also determine the track validation threshold. The performance of these two procedures is investigated through simulation of an active sonar tracking scenario by comparing the false and true track acceptance probabilities.

A review is presented of the current status of offshore wind energy in Europe. This paper is based around the project Concerted Action for Offshore Wind Energy in Europe (CA-OWEE) which aims to define the current state of the art of offshore wind energy in Europe through gathering and evaluation of information from across Europe and to spread the resulting knowledge to all interested to help stimulate the industry's development. After some background information a brief history is given of offshore wind energy in Europe followed by the current situation. Next offshore wind energy technology is considered. Lastly concerted action on offshore wind energy in Europe is outlined.

Oil in water has been traditionally measured by Freon extraction and IR (infrared) analysis. Since the ban on the use of Freon the method and the whole monitoring regime have been under review. There has been a lot of activity in the attempt to identify a Freon replacement and-or an alternative analysis method. A new method ISO 9377-2 GC-FID has led OSPAR to consider seriously whether to recommend it as a replacement reference method for the old IR method. A number of studies have been carried out to see if the method is suitable. A further study involving a considerable number of offshore installations has been planned by OSPAR to compare the old IR method and a modified version of ISO 9377-2 GC-FID. It is hoped that this will confirm if such a method is suitable. However even if such a method is recommended for offshore routing monitoring alternative methods are still considered to be necessary. Final conclusions are drawn.

Results of a study undertaken in 1971-1972 are presented and cover quantities of bilge and ballast oil and water existing types of separators theoretical considerations and factors affecting separator selection. The Aker Comyn Firtop Shell Parallel and Tilted Plates Turbulo Victor Butterworth Bilgewater Fram/Aker and Electrolytic Separators are described and costs of manually operated semi-automatic and automatic separators are tabulated. Evaluation of oil content monitors indicated that the most accurate was the Fram Fluid Analyser or the APV Bowser Turbidimeter and the use of reliable monitors in conjunction with load-on-top techniques was potentially more cost effective than improved de-ballasting separators.

Generally the specification for a naval ship will define the design lifetime design speed profile and the operational environment in which the ship is required to operate. More recently with the introduction of novel hull forms and the wider variety of tasks being performed by naval ships including littoral operations there has been a requirement to undertake a risk-assessment-based approach to the determination of the structural adequacy of the hull. This implies the need for a probabilistic approach to define a ship's operational profile and to assess the risk of structural failure. Some research is presented whose focus is the influence of a ship's operational profile on structural risk assessment. This research was recently undertaken by DSTO (the Defence Science and Technology Organisation) to provide RAN (the Royal Australian Navy) with an ability to incorporate conditional probabilities within operation profiles of surface platforms. The research is described. An example calculation of extreme and fatigue load analysis demonstrates the importance of realistic operational profile definitions. A case study is presented and its results are presented and discussed. Conclusions are drawn.

With the advent of acoustic modem technology the number of applications in which underwater sensors and robots are connected through a communication network is growing. One such application is the search for deep-sea hydro-thermal vents by a small group of AUVs (autonomous underwater vehicles). The vehicles are equipped with acoustic modems. Acoustic modems typically operate in half-duplex which limits the choice of a data link control protocol to the S and W (stop and wait type. Unfortunately on channels with poor quality and long propagation delay - such as the majority of acoustic channels -) S and W protocol has low throughput efficiency. The basic S and W can be improved by using a modification in which packets are transmitted in groups and acknowledged selectively. Throughput efficiency can now be maximised by selecting the optimal packet size which is a function of range rate and error probability. Quantitative analysis for typical acoustic links shows that modified S and W protocols offer good performance provided that packet size is chosen close to optimal. In addition as the group size increases sensitivity to packet size selection is reduced.

With a sharp increase in oil prices even higher propulsive efficiency is required to save energy. Traditionally propellers have been designed using criteria such as Lerbs optimum based on the lifting line theory and the empirical formulae of Lerbs and van Manen which relates the wake pitch to wake non-uniformity. By using a high-speed computer it is now possible to apply time-consuming iterative approaches to solve lifting surface problems. The variational problem is formulated to optimise the efficiency of the propeller operating in a given ship's wake using the lifting surface method. The variational formulation relating the spanwise circulation distribution to the propulsive efficiency to be maximised is however non-linear in circulation distribution functions thus an iterative method is applied to the quasi-linearised equations.

Calculating the cost of a vessel in the early design stages can be difficult. Aspects of the design may yet to be determined leading to a great deal of uncertainty. Consequently there is little incentive to look into the costs of a design in anything more than an indicative manner. Paramarine's early stage design environment is based on the Building Blocks methodology developed by UCL. Combined with a parametrically defined structural definition the complete design can be deconstructed into materials equipment and construction activities allowing the production to be evaluated before reaching the initial design stage. In both areas of the software searchable design data is associated with semantic information (space weight type etc.) which can be audited to identify items for cost evaluation. Time to perform a cost evaluation is reduced as is the potential for mistakes. However the designer is left with just having to assign a cost value a potentially laborious process. The challenge of automating the process of cost assignment by using the semantic information associated with each item to determine how it is produced is discussed.

In this paper the design methodology and the experimental results obtained through a novel passive-acoustic based device for quantifying the gas flux from bubble plumes and marine seeps are presented. In order to estimate gas flux variations a gas capture buoy is designed. The seep environment is simulated by forcing compressed air through a submerged tube. Different flow rates are generated by changing only the pressure of the supplied air. The assembly collects gas and redirects it through a nozzle mounted on top of a collector where the sound of the gas leaving the nozzle is recorded through a single hydrophone. A quantitative gas flux estimate is made using a Morlet wavelet based analysis of the recorded sound signals series. The data from the acoustic measurement is compared with the data from the visual measurements as well as with the measurements at a gas flow meter.

Line arrays are widely used in underwater acoustic environments to measure the propagation of acoustic waves. A method is presented to optimise beam-pattern for line array with faulty elements. The faulty element means that the sensor has no output or its gain is greatly reduced compared to other normal sensors. It is not easy to form an ideal beam in unstable undersea environments. In the case of faulty elements the average side-lobe level on beam-pattern is higher and the faulty elements generate the distorted beam-pattern. A method is proposed to compensate the distorted beam-pattern. This method calculates the weights to minimise the squared error between the ideal pattern and the distorted pattern. The criteria have a constraint about faulty elements. The performance of the method is evaluated in various environments using computer simulation.

In offshore oil or gas exploration jack-up rigs using individual foundations have been used since the early 1950s. This type of structure usually has three legs. The large pad footing at the base is called spudcan. Offshore spudcan foundations penetrating into NC (normally consolidated) clay are studied using FE (finite element) method and UB (upper bound) analysis. H-adaptive RITSS (remeshing and interpolation technique with small strain model) is used in continuous penetration simulation. The results show firstly that the upper bound can give reasonable predictions on its bearing capacity with different pre-embedment depth; and secondly that the continuous penetration resistance is lower than the pre-embedded resistance. It is concluded that care should be taken when penetration depth needs to be predicted during installation.

Russia is a European power even though it has a large part located in geographic Asia. Non-Russian Asia does not border on the Arctic and has no tradition of looking north. After a brief review of the agenda some conceptual issues related to Northeast Asia are clarified. Next several issues are considered - (1) what are the main perceptions (and mis-perceptions) existing between Russia/Russian Far East (RFE) and its Northeast Asian neighbours? (2) How do these perceptions hinder increased co-operation between Russia/RFE and its Northeast Asian neighbours? and (3) Does such co-operation have a viable future?

Modern warships are being developed with requirements for greater performance and capability within a climate of shrinking defence budgets and increasing fuel costs. This places greater demand on the heat management system to reject higher levels of wild heat especially whilst operating in extreme climates. Future platforms will require sufficient installed heating and cooling capacity to meet the most extreme operational and environmental conditions whilst optimising the heat management system for low running costs. This paper investigates methods to improve heat management efficiency for an FSC (future surface combatant) concept design. Performance and cost issues have been assessed by reviewing existing and emerging technologies and comparing thermal modelling for an FSC concept design against current naval practice for HVAC design.

Performance management and improvement are essential activities that ports use to enhance their competitive position in the global market. This topic is investigated for container ports. The sensitivity of the performance enablers in the port performance model of Jaffar and Barry is explored. The performance measure that is used in this model for the container ports is the TEU (twenty equivalent unit) and the port performance predictor variables were: leadership commitment to excellence modern technology the efficiency of the terminal port size and the port hinterland. The change of the TEU over 5 years (1999-2003) is investigated using time series analysis. The sample that was used includes container ports in the Middle East Far East and Europe. Based on this sample it is suggested that the most sensitive enablers affecting the performance of container ports are the port capacity and the crane productivity.

The work carried out to predict the behaviour of a 0.6 m Impulse turbine with fixed guide vanes of 0.6 H-T (hub to tip) ratio under real sea conditions is presented. Water surface elevation verses time history based on Pierson Moskowitz Spectra was used as the input data. A typical OWC (oscillating water column) geometry has been used for this simulation. Standard numerical techniques were used to solve the non-linear behaviour of the sea waves. Considering the quasi-steady assumption unidirectional steady flow experimental data was used to simulate the turbine characteristics under irregular unsteady flow conditions.

Although the shipbuilding industry of Japan is still competitive in the world ship market the situation of the industry has changed greatly from the Oil Shock period. Japanese shipyards have achieved the world highest efficiency in design and production processes in the 30 years since then so that the demand for researchers and engineers specialising in naval architecture has decreased. The industry now needs different kinds of human resources with diverse knowledge and the ability to solve complex problems. In order to meet this change the University of Tokyo carried out a major reform of the faculties and departments related to the naval architecture and ocean engineering research and education. In this paper an overview of the reform and underlying vision on research and education is presented.

This paper presents a method to create high resolution spatial models of underwater scenes from optical images. In this paper an automated procedure to construct larger photogrammetric model from sets of still images is considered. The process is automated in the sense that there is no human interaction in the photogrammetric interpretation of the images. Next the paper presents the framework and methodology for producing large scale underwater photogrammetric models. The requirements to the data-acquisition process of the images for the photogrammetry are laid out. Local models are constructed from image pairs before they are assimilated into a global model while computing the internal error. After this the paper describes the data acquisition the data processing and the resulting model for a dataset collected at an archaeology excavation at 170 meters depth. Lastly the method and the performance on the dataset is discussed.

To power small unattended sensors during long endurance missions it is necessary to have a renewable energy source. This work develops a novel small-scale generator capable of extracting up to one watt of power from the flow in ocean currents streams and pipes. In order to accomplish this goal an energy-harvesting eel has been constructed from piezoelectric materials. Thin flexible piezoelectric membranes or 'eels' are mounted aft of a rectangular bluff body and are excited by vortex shedding in the wake of the body. This flapping motion generates strain energy in the material that can be converted to electric power and stored in a battery to power small sensors and an acoustic modem. Here we report new experiments on the behaviour of multiple eels stacked vertically behind a single bluff body.

This paper presents SCR (steel catenary riser) design for the BP King development a subsea tieback to the Marlin TLP (tension leg platform) located in the Gulf of Mexico in Viosca Knoll Block 915. The King PIP SCR with heated water flowing in the annulus is a relatively novel SCR system in the offshore industry. An overview of the challenges and issues encountered in the PIP SCR design for this project are presented. The issues and challenges encountered in the PIP SCR design for this project are discussed. Diagrams appear on pages 11 to 19.

A review of Discovery Producer Services' GC 209 Lateral Pipeline Project (formerly referred to as the Allegheny Lateral) is presented. The design fabrication testing and installation of the PLES (lateral's pipeline end-sleds) and 12-inch OD rigid interconnecting jumper located in Green Canyon 209 receive special attention. Various technical challenges are addressed. The issues and solutions presented should help in future design development and expansion of a deepwater pipeline transmission system. The successful use of large diameter high-pressure diverless connections will help in the establishment of a future transmission infrastructure beyond the continental shelf. Photographs and diagrams appear on pages 6 to 10.