The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In this paper, the natural supercavitys are studied both experimentally and numerically. A series of supercavitating vehicle water-entry test are carried out at different speeds, where it is found that the minimum pressure in the cavity gradually reduced with the increase of water-entry speed. The cause for the evolution progress of natural supercavitation is difficult to get from the experiment,...
In this study, numerical investigations of flow characteristics of a pumpjet propulsor based on Computational Fluid Dynamics (CFD) method have been presented. The Zwart-Gerber-Belamri (Z-G-B) cavitation model based on the Reynolds Averaged Navier-Stokes (RANS) method is employed. The structured gird is applied. A four-blade skewed E779A propeller has been used to verify the numerical method. The comparison...
Bidomain or monodomain model has frequently been used to study electrical activities in the cardiac tissue. The finite difference method with second order accuracy is commonly used to approximate the spatial derivatives of the governing equations numerically. In this work, a higher order finite difference scheme has been implemented to solve the nonlinear monodomain equation. The unknown transmembrane...
Attributes, such as metadata and profile, carry useful information which in principle can help improve accuracy in recommender systems. However, existing approaches have difficulty in fully leveraging attribute information due to practical challenges such as heterogeneity and sparseness. These approaches also fail to combine recurrent neural networks which have recently shown effectiveness in item...
Meshless methods to simulate fluid flows have been increasingly evolving through the years since they are a great alternative to deal with large deformations, which is where mesh-based methods fail to perform efficiently. A well known meshless method is the Moving Particle Semi-implicit (MPS) method, which was designed to simulate free-surface truly incompressible fluid flows. Many variations and...
The design of blind rendezvous strategies for dynamic spectrum access in multi-users, multi-hop networks is a challenging task. In this paper, a two radios synchronization strategy that minimizes the time to rendezvous in multi-users networks is analyze. In fact, it has been recently demonstrated that this synchronization strategy provides optimum results in terms of maximum time to rendezvous (MTTR)...
We present a novel approach for estimating conditional probability tables, based on a joint, rather than independent, estimate of the conditional distributions belonging to the same table. We derive exact analytical expressions for the estimators and we analyse their properties both analytically and via simulation. We then apply this method to the estimation of parameters in a Bayesian network. Given...
This paper presents the development of a real-time Supervision Hardware-in-the-Loop (HIL) emulator of shaded PV systems. This study is focused on shaded conditions due to the impact of shadows in the final energy production and the global structural healthy. In this context, we propose a methodology to emulate in real-time the shaded PV system behavior. This proposed methodology is intended for evaluation...
A new class of graphs is introduced in preferential attachment random graphs theory, these graphs are grown by adding an infinite number of complex stochastic increments, consisting of several interconnected vertices. The problems of final degree distributions for vertices and edges of growing graphs are solved by analytic methods. Analytic solution of a graph calibration (synthesis) problem due to...
A study of signal control effects on vehicle's emissions through a sequence of traffic lights was conducted. To describe the states of traffic lights, a signal state function was proposed. Meanwhile, a modified car-following model was developed and applied to show the traffic behaviors at signalized intersections on a roadway. The moving behavior of vehicle was discussed in three modes: free running...
In off-grid renewable power systems, batteries are often used to balance the mismatch between load and electricity generation. The mismatch may be more severe in small-scale systems due to the lack of averaging effect seen in larger power systems. In the former, batteries have to cope with rapid power fluctuations whilst still delivering power to consumers. A vanadium redox flow battery (VRB) may...
In this paper, 2-Dimensional and 3-Dimensional numerical models of a thermal flow sensor are discussed and compared against one another whilst being validated with experimental results. The models involve and couple three physics domains: electric, computational fluid dynamics and heat transfer. A comparative analysis has been performed focusing on the relative merits. Despite being less accurate,...
Unmanned Aerial Vehicles (UAVs) are used in all kinds of applications. The utilization of multiple UAVs acting in a cooperative manner within the same operation field is especially interesting. However, many deployment scenarios pose the challenge of continuous applications. UAVs are equipped with a limited battery which enables short term applications. Replacement and recharging maintenance processes...
The interferometry problem addresses the estimation of an unknown quantity exploiting the interference among measurements from different sources. These measurements are obtained from the Fourier domain but are sparse and contaminated with noise. We propose a parametric, sum-of-basis, model for these observations together with a Bayesian approach for reconstructing interferometry images. Our main contributions...
A convex-optimization approach to H2/H∞ Model-order Reduction (MoR) of continuous-time Linear Time-Invariant (LTI) systems is presented. The new numerical algorithm provides more information about the performance of the reduced-order model and generalizes the previous designs based upon H2 and H∞ norm minimization. Connection between the optimal projection methods and the proposed H2/H∞ algorithm...
Discrete time-varying problems are frequently encountered in mathematics and engineering fields, such as numerical analysis, signal processing and computer computing. However, conventional algorithms mainly solve time-invariant problems. Employed for discrete time-varying problems solving, conventional algorithms may generate quite large and unacceptable lagging errors. In this paper, discrete time-varying...
In learning and development, students need to be made aware of their slips and mistakes in terms of acquiring the required knowledge, skills and competencies, especially, in active learning approaches. However, assessments may not necessarily lead to an effective understanding of student's errors. Most assessors are required to measure the extent of student's accurate output in terms of exam answers...
In this study, the flow characteristics of a round laminar air jet impinging on walls with different patterns are experimentally and numerically investigated. A smooth solid wall and a set of walls with one-direction square- and triangular-shaped grooves are used. Direct visualizations using high speed/resolution camera are performed. The evolution of the turbulent structures in the area where the...
This paper presents the derivation, in great detail, of the full nonlinear model for a quad-copter, using D'Alembert's principle. The final model is presented in a form suitable for simulation and control. Finally, the quad-copter model is implemented and a simple control law for the attitude and altitude are derived. Numerical results are presented at the end of the paper.
For simulations of multiple-input multiple-output (MIMO) narrowband channel between the Unmanned Aerial Vehicle (UAV) and the ground user, we describe the distribution of scatterers by using a cylindrical model, and propose a corresponding deterministic simulation model and a statistical simulation model. In order to verify the practicability of the simulation model, this paper compares the temporal...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.