Search results for "Floating"
showing 10 items of 61 documents
Nonlinear systems solver in floating-point arithmetic using LP reduction
2009
This paper presents a new solver for systems of nonlinear equations. Such systems occur in Geometric Constraint Solving, e.g., when dimensioning parts in CAD-CAM, or when computing the topology of sets defined by nonlinear inequalities. The paper does not consider the problem of decomposing the system and assembling solutions of subsystems. It focuses on the numerical resolution of well-constrained systems. Instead of computing an exponential number of coefficients in the tensorial Bernstein basis, we resort to linear programming for computing range bounds of system equations or domain reductions of system variables. Linear programming is performed on a so called Bernstein polytope: though,…
An Innovative dosimeter based on a floating Gate sensor
2019
This work describes the development of a new method for recording radiation exposure by using a passive dosimeter based on a Floating Gate CMOS sensor. The floating Gate sensors based on the MOS structure discharge allow the construction of compact and cost-efficient dosimeters, realized in VLSI CMOS technology, for use in integration mode in various applications, in particular in radiotherapy.
Gain Scheduling H 2 / H ∞ Structural Control of a Floating Wind Turbine
2014
Abstract For wind turbine load mitigation, this paper proposes an active structural control deign of a hybrid mass damper installed at the tower top of a spar-type floating wind turbine. System dynamic model is established based on first principles and the polynomial curve fitting approach, while different steady-state points are derived. Then, a gain scheduling H 2 / H ∞ state feedback controller is designed by solving linear matrix inequalities, which aims to reduce the loading. At last, nonlinear simulations are performed under different wind and wave conditions, and the results demonstrate that more load reduction could be achieved at the expense of more energy consumption in mass dampe…
Robust output feedback &#x210C;<inf>&#x221E;</inf> control synthesis with pole placement for offshore wind turbine system: An LMI…
2012
This paper deals with output ℌ ∞ control synthesis for a linear parameter-varying model of a floating wind turbine. A nonlinear model is introduced and linearized to obtain a linear model for each desired azimuth angle using the wind turbine software FAST. The main contributions of this paper are threefold. Firstly, the family of linear models are represented based on an affine parameter-varying model structure. Secondly, the bounded parameter-varying parameters are removed using upper bounded inequalities in the control design process. Thirdly, the control problem is formulated in terms of linear matrix inequalities (LMIs). The simulation results show a comparison between a controller desi…
Semiactive control for floating offshore wind turbines subject to aero-hydro dynamic loads
2011
Wind and wave dynamic loads might cause undesirable vibrations that affect the structure integrity and system performance of floating offshore wind turbines. This paper addresses the problem of dynamic load mitigation by using semiactive control techniques with the tuned liquid column dampers placed on the turbine’s tower. The control law is formulated based on the mixed H2/H∞ methods for ensuring the system stability and reliability. Furthermore, the proposed controller only uses output feedback so as to avoid the dependence on the knowledge of the states of the system. Peer Reviewed
Agent-based test-bed for road information systems
2012
Road safety is one of the most important concerns of road authorities. In order to improve road safety, traffic managers develop traffic management and control strategies. The use of advanced traffic management systems is to support road managers in daily traffic management tasks. However, it is important to test in advance, the traffic strategies to evaluate the results and their suitability to the current situation. In this study, a test-bed based on multi-agent is presented. The purpose of this test-bed is to be able to test several traffic information strategies in case of adverse weather situations. It consists in a knowledge model implemented by a set of basic agents. These agents are…
Can Atmospheric Neutrons Induce Soft Errors in NAND Floating Gate Memories?
2009
Atmospheric neutrons can interact with the matter inside a microelectronic chip and generate ionizing particles, which in turn can change the state of one or more memory bits [soft error (SE)]. In this letter, we show that SEs are possible in Flash memories, although with extremely low probabilities. While this problem will increase for future technologies, we do not expect SEs to be the reliability limiting factor for further floating gate scaling.
Second-order hydrodynamic effects on the response of three semisubmersible floating offshore wind turbines
2020
Abstract Floating structures have become the most feasible solution for supporting wind turbines when offshore wind project move to deeper water. In this paper, a hydrodynamic analysis of three different semisubmersible floating offshore wind turbines is carried out including second-order hydrodynamic effects. The three examined platforms are V-shaped semisubmersible, Braceless semisubmersible and OC4-DeepCwind semisubmersible and are used to support the NREL 5 MW reference wind turbine. The main objective of the present study is to investigate and compare the hydrodynamic response of the three different semisubmersible floaters in two water depths (100 m, and 200 m) under different load co…
Transient response of a TLP-type floating offshore wind turbine under tendon failure conditions
2021
Abstract Among various types of floating offshore wind turbines (FOWTs), the tension leg platform (TLP) floating wind turbines have relatively small motions due to stiff tendons. Similar to TLP applications in the offshore industry, tendon failure may lead to deteriorated stability and large transient responses, which should be considered as part of accidental limit state (ALS) checks at the design stage of the TLP FOWTs. This paper takes the WindStar TLP system as a representative and investigates the transient effects of one-tendon failure on the system responses. A coupled numerical model is first established using the aero-hydro-servo-elastic simulation tool FAST. Subsequent numerical s…
STUDY REGARDING THE EVOLUTION OF THE FINANCIAL BALANCE IN THE PHARMACEUTICAL INDUSTRY
2015
Abstract This article aims at analysing the financial balance within the global pharmaceutical industry, starting from the assumption that „In the pharmaceutical industry there is sufficient liquidity to cover payment obligations”. The analysed companies are part of the exclusive group comprising the top 20 global companies, e.g. GlaxoSmithKline, Merck & Co., Sanofi-Aventis and Bayer. The research conducted is based on an analysis over time of the relationship between floating assets, floating assets requirement and net cash from 2006 to 2013, and highlights the main developments of the indicators before the onset of the financial and economic crisis and after its outbreak.