This paper describes a computer-based, dynamic positioning system for floating vessels. The system is based on a detailed mathematical model of vessel motion in response to forces from thrusters, wind, waves and water current. The system uses a Kalman filter for optimal estimation of vessel motions and environmental forces from wind, waves and current. The control system is based on feedback from the motion variables where the oscillatory, wave-induced component is removed by the estimator. Feedback from the water current estimate provides the integral action of the system and feed forward from the wind force estimates are implemented. Simulation results and recordings from actual operation of the system indicate an excellent system performance
Diabetes is a metabolic disorder that results in human body due to insulin deficiency, insulin resistance or both. In the management of diabetes, glucose monitoring technology has been used for the last three decades. The aim of this review article is to describe concise and organized information about different techniques of non-invasive continuous blood glucose monitoring. Many research groups have been working to develop wearable sensors for continuous blood glucose monitoring, but at present, there are to our knowledge no commercially successful non-invasive glucose monitors on the market. To achieve an acceptable sensor system, a glucose sensor should have accuracy better than 15mg/dl (0.8 mmol/l).In future development, continuous glucose sensor systems may become predictable, selective, reliable and acceptable for patient use.
This paper describes a computer-based, dynamic positioning system for floating vessels. The system is based on a detailed mathematical model of vessel motioninresponse to forces from thrusters, wind, waves and water current. The system uses a Kalman filter for optimal estimation of vessel motions and enviromental forces from wind, waves and current. The control where the oscillatory, wave-induced component is system is based on feedback from the motion variables removed by the estimator. Feedback from the water current estimate provides the integral action of the system and feed forward from the wind force estimates are implemented. Simulation results and recordings from actual operation of the system indicate an excellent system performance. Reference is given to installations made on actual vessels.
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AbstractIn oil rim fields a thin oil layer lies between an aquifer and a gas cap. Oil may be produced from such fields using horizontal wells. Production will lower the local gas/oil contact near the well in a process called gas coning (or more accurately, cresting). After gas breakthrough, the gas/oil ratio (GOR) from the well may vary strongly with the production rate. The ability to predict this dependency is essential for production optimisation for such fields.We have developed a mathematical model that can predict gas coning behaviour and the resulting rate dependent GOR with a surprisingly high degree of accuracy over periods of several months or more. We combine a dynamic model that describes the essential reservoir behaviour with a highly simplified description of the interaction between the well and the surrounding reservoir. The full model has three adjustable parameters that allow us to fit the behaviour to individual wells, using historical oil and gas production rates. The model forms the basis of the GORM (Gas/Oil Ratio Model) computer program that since early 2003 is in regular use for production planning and optimisation at the Troll field. We have also tested the model on wells in other fields, with encouraging results.
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