In this paper we derive a necessary and sufficient condition for observing the initial condition of a new class of system known as the perspective system. Such a system has already been applied in the field of computer vision especially in the area of motion estimation problems. Our result generalizes an earlier result by Popov-Belevitch-Hautus on the problem of observing a linear dynamical system. 相似文献
Motivated by problems in vision and robotics, in this paper we are interested in describing the dynamics of planar algebraic
curves in rigid and affine motion. A new method is presented for modeling the dynamics of such curves in terms of Riccati
equations. It is shown that rigid or affine motion of an algebraic curve can be described using the dynamics of line factors obtained from a unique decomposition of the curve, and each individual line dynamics can be described by a Riccati equation.
An estimation algorithm is proposed to estimate rigid or affine motion using line parameters. Importance of data normalization
is also investigated in the context of motion estimation. Experiments with simulated data and real images demonstrate that
the proposed method can provide satisfactory motion estimation results from perturbed data. 相似文献
In this article, we investigate a transient magnetohydrodynamic convective micropolar fluid flow over a semi-infinite vertical plate embedded in a porous medium in the presence of chemical reaction and thermal diffusion. The dimensionless governing equations are solved by adopting the regular perturbation technique. The impact of various parameters on the velocity, microrotation, temperature, concentration profiles, skin friction, Sherwood number, and Nusselt number over the boundary layer is analyzed using graphs. The fluid velocity and microrotation reduce under the effect of thermal diffusion and chemical reaction. Furthermore, concentration rises due to thermal diffusion (Soret) effect, but concentration falls under the effect of chemical reaction. It is found that the velocity and skin friction fall with enhancing value of magnetic parameter. But Sherwood number increases as the magnetic parameter increase. 相似文献
This study deals with an analysis of the time-dependent dynamics of micropolar fluid flow subject to Lorentz force, diffusion thermal, and viscous dissipation effect past a uniformly moving semi-infinite porous plate in the presence of chemical reaction. Expressions of velocity, microrotation, concentration, temperature, skin friction, Sherwood number, and Nusselt number are established and the effect of several parameters on them are represented graphically. Equations governing the flow and heat transfer are solved by adopting the regular perturbation technique. It is noticed that temperature distribution as well as the coefficient of friction is enhanced due to the diffusion thermo effect. It is observed that the microrotation increases with increasing magnetic parameters. Furthermore, the study confirms a drop in fluid concentration under the composition of species. 相似文献
This paper presents a hierarchical critic learning optimal control (H-CLOC) strategy for a lower limb exoskeleton system with prescribed state constraints. The prescribed state constraints of the exoskeleton are mathematically modeled by means of a state error transition function, which transforms the constrained state into an equivalent new unconstrained state. A hierarchical framework including a high-level motion trajectory planner and a low-level critic learning (CL) controller is proposed for optimal control of the exoskeleton. The estimation of human motion intentions is achieved using dynamic movement primitives (DMPs), which are capable of accurately replicating the original training trajectories during motion. The CL algorithm is implemented on the transformed unconstrained system while enhancing the learning capability of the proposed algorithm for the exoskeleton. The optimal control with prescribed constraints is analyzed for stability using the Lyapunov theorem. Finally, simulation results validate the effectiveness of the proposed H-CLOC strategy for lower limb exoskeletons. 相似文献
In this paper, Pd modified WO3 thin film methanol sensor has been developed by sol–gel method. WCl6 chemical compound is used as a precursor. Spin coating method is employed for the preparation of the WO3 thin film on the Si substrate. The crystalline structure of the WO3 thin film is analyzed by scanning electron microscopy and X-ray diffraction techniques. The thin film sensor is fabricated at different annealing temperatures (400, 600 and 800 °C). The response magnitude of the WO3 thin film is studied at different operating temperatures (100–300 °C). It is observed that the operating temperature of Pd modified thin film sensor is 200 °C. It is also noticed that the maximum response magnitude of Pd modified WO3 thin film sensor is found at the annealing temperature of 600 °C. It is found that Pd modified WO3 thin film sensor are suitable for methanol vapour detection compare to unmodified WO3 thin film senor.
Antimycotic agents : Diverse classes of antimycotic drugs have been developed over the past decades with the goal of improving selectivity and efficacy. This review discusses both conventional and novel targets for antifungal agents and the possibility of vaccination in the treatment of invasive fungal infections.
Transport sector in India accounts for 20 % of total commercial energy demand of the country, of which a considerable amount is consumed in the form of liquid and gaseous fuel. A major part of these fuels are imported by the Government. Apart from the import expenditure, Government of India has subsidized these fuels to make it available at affordable prices. To check the financial burden and achieve environmental benefits, technical advancement in present system or alternative infrastructure is required. The present study examines the possible impacts on economy and environment by the implementation of battery electric vehicles (BEVs) along with the conventional road transport system in metropolitans with a case study of Kolkata. The major impact has been observed in controlling the vehicular emission with a decrease in CO2 level by 26.27 t per day, on replacement of only 2 % of the present public transport by suitable BEVs. Maintaining similar service for the passengers the electrical energy required by the alternative vehicles has been estimated to be 41,766 kWh per day. This energy has been proposed to be supplied by remodeled fuel stations equipped with solar photovoltaic systems, if charging strategy is based on renewable sources. In case of fuel economy, the infrastructure has shown the potential in reducing the consumption of diesel and autogas (LPG) by 11,654 and 3,256 liter per day, respectively. 相似文献
In this paper we consider the problem of estimating the range information of features on an affine plane in
by observing its image with the aid of a CCD camera, wherein we assume that the camera is undergoing a known motion. The features considered are points, lines and planar curves located on planar surfaces of static objects. The dynamics of the moving projections of the features on the image plane have been described as a suitable differential equation on an appropriate feature space. This dynamics is used to estimate feature parameters from which the range information is readily available. In this paper the proposed identification has been carried out via a newly introduced identifier based observer. Performance of the observer has been studied via simulation. 相似文献