4,805 research outputs found
A path planning control for a vessel dynamic positioning system based on robust adaptive fuzzy strategy
The thrusters and propulsion propellers systems, as well as the operating situations, are all well-known nonlinearities which are caused less accuracy of the dynamic positioning system (DPS) of vessels in the path planning control process. In this study, to enhance the robust performance of the DPS, we proposed a robust adaptive fuzzy control model to reduce the effect of uncertainty problems and disturbances on the DPS. Firstly, the adaptive fuzzy controller with adaptive law is designed to adjust the membership function of the fuzzy controller to minimize the error in path planning control of the vessel. Secondly, the H∞ performance of robust tracking is proved by the Lyapunov theory. Moreover, compared to the other controller, a simulation experiment comprising two case studies confirmed the efficiency of the approach. Finally, the results showed that the proposed controller reaches control quality, performance and stability
Fuzzy adaptive interactive algorithm design for marine dynamic positioning system under unexpected impacts of Vietnam Sea
1764-1771The factors which affect vessel motion mainly come from environmental influences. In the actual conditions, each of the oceans will exhibit different characteristics. This paper aims todevelop a fuzzy adaptive interactive (FAI) algorithm for the marine dynamic positioning system (DPs) under unexpected impacts of the Vietnam Sea. The response error ξ between the ideal model and the actual model helps to estimate more accurately the variation amplitude caused by nonlinear components. Based on the response error ξ, the control signal of actual model which is adjusted suitably to the ideal model proceeds the DPs maintain the vessel in a position under the environmental conditions of Vietnam Sea. On the other hand, the impact parameters are explored by the actual conditions to increase the reliability of the proposed solution. Simulation results of the FAI are evaluated in comparison with other methods such as fuzzy. The FAI performs the desired response of DPs better than other in two case studies, that proved the effective for the proposed controller
Assessment of the Effectiveness of Ich Tam Khang as a Supportive Therapy for Chronic Heart Failure
Background: Heart failure is a chronic disease needing lifelong management. Despite the advances that have been made in the treatment of the disease, both the longevity and quality of life for those with chronic heart failure remain impaired. A more effective therapeutic approach with less negative side effects is still needed. In this study, we evaluate Ich Tam Khang (ITK), the poly-ingredient herbal and nutritional preparation with multiple physiological actions, as a supportive therapy for patients with chronic heart failure.Aims of Study: To evaluate the effectiveness and safety of Ich Tam Khang as an adjunctive treatment of chronic heart failure.Methods: A total of 60 patients with chronic congestive heart failure were enrolled in this open label, cross-sectional and prospective study. All patients were treated with a conventional regimen (digoxin, diuretics, angiotensin-converting-enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs), beta blockers) for at least 4 weeks before being divided into two equal groups. In the treated patients with ITK, patients received conventional therapy plus 4 tablets ITK per day added in two divided doses. In the control patients, all patients kept the same conventional regimen without ITK. All patients were followed up for 3 months for clinical and para-clinical outcomes.Result: The symptoms of heart failure (dyspnea, palpitation, peripheral edema, neck vein distention, heptojugular reflex) decreased. Heart rate and blood pressure stabilized during treatment in the treated patients with ITK. Additionally, total cholesterol and HDL-cholesterol normalized in the patients treated with ITK. Most of echocardiography parameters in the ITK treated patients were superior to the control patients. ITK is safe and it has no side effects.Conclusion: ITK as a combination of herbal and nutritional preparation is effective in reducing heart failure symptoms, improving patient's quality of life for the patients with decompensated heart failure and reducing total cholesterol and LDL-C
Bounded Verification with On-the-Fly Discrepancy Computation
Simulation-based verification algorithms can provide formal safety guarantees
for nonlinear and hybrid systems. The previous algorithms rely on user provided
model annotations called discrepancy function, which are crucial for computing
reachtubes from simulations. In this paper, we eliminate this requirement by
presenting an algorithm for computing piece-wise exponential discrepancy
functions. The algorithm relies on computing local convergence or divergence
rates of trajectories along a simulation using a coarse over-approximation of
the reach set and bounding the maximal eigenvalue of the Jacobian over this
over-approximation. The resulting discrepancy function preserves the soundness
and the relative completeness of the verification algorithm. We also provide a
coordinate transformation method to improve the local estimates for the
convergence or divergence rates in practical examples. We extend the method to
get the input-to-state discrepancy of nonlinear dynamical systems which can be
used for compositional analysis. Our experiments show that the approach is
effective in terms of running time for several benchmark problems, scales
reasonably to larger dimensional systems, and compares favorably with respect
to available tools for nonlinear models.Comment: 24 page
The hyperon mean free paths in the relativistic mean field
The - and -hyperon mean free paths in nuclei are firstly
calculated in the relativistic mean field (RMF) theory. The real parts of the
optical potential are derived from the RMF approach, while the imaginary parts
are obtained from those of nucleons with the relations:
and . With the
assumption, the depth of the imaginary potential for is
3.5 MeV, and for is 7 MeV at
low incident energy. We find that, the hyperon mean free path decreases with
the increase of the hyperon incident energies, from 200 MeV to 800 MeV; and in
the interior of the nuclei, the mean free path is about fm for
, and about fm for , depending on the hyperon
incident energy.Comment: 5 figures, 6 page
A Unified Quantum NOT Gate
We study the feasibility of implementing a quantum NOT gate (approximate)
when the quantum state lies between two latitudes on the Bloch's sphere and
present an analytical formula for the optimized 1-to- quantum NOT gate. Our
result generalizes previous results concerning quantum NOT gate for a quantum
state distributed uniformly on the whole Bloch sphere as well as the phase
covariant quantum state. We have also shown that such 1-to- optimized NOT
gate can be implemented using a sequential generation scheme via matrix product
states (MPS)
Effect of Wine Closures on the Aroma Properties of Chardonnay Wines after Four Years of Storage
The effects of wine closures on the sensory properties and aroma profiles of fresh Chardonnay wines wereevaluated after four years of bottle storage. Natural cork closure, technical cork closure, Nomacorc light,Nomacorc classic and Nomacorc premium were investigated. Among these wines sealing with differentclosures, the physicochemical parameters of the wine samples showed no significant differences, exceptthat of the free and total sulphur dioxide. Nomacorc light with the highest OTR (oxygen transition rate)had the least residual free sulphur dioxide. Most of volatiles were generally stable, and seven compounds(acetoin, 1-butanol, 2-phenylethanol, 1-pentanol, (Z)-3-hexen-1-ol, 2-nonanol and ethyl decanoate) weresignificantly affected by the wine closures. The sensory analysis revealed that cork closures preserved morefruity/flowery characters of the fresh wines after four years’ storage, as well as cork-tainted off-flavour.Two synthetic closures (Nomacorc light, Nomacorc classic) imparted some grilled attributes to the wines.Nomacorc premium highly reserved the fruity/flowery flavour without cork contamination or oxidisedtoasted characters
Growth of High-Mobility Bi2Te2Se Nanoplatelets on hBN Sheets by van der Waals Epitaxy
The electrical detection of the surface states of topological insulators is
strongly impeded by the interference of bulk conduction, which commonly arises
due to pronounced doping associated with the formation of lattice defects. As
exemplified by the topological insulator Bi2Te2Se, we show that via van der
Waals epitaxial growth on thin hBN substrates the structural quality of such
nanoplatelets can be substantially improved. The surface state carrier mobility
of nanoplatelets on hBN is increased by a factor of about 3 compared to
platelets on conventional Si/SiOx substrates, which enables the observation of
well-developed Shubnikov-de Haas oscillations. We furthermore demonstrate the
possibility to effectively tune the Fermi level position in the films with the
aid of a back gate
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