small time interval
Recently Published Documents


TOTAL DOCUMENTS

23
(FIVE YEARS 2)

H-INDEX

7
(FIVE YEARS 0)

2021 ◽  
Vol 26 (3) ◽  
pp. 503-518
Author(s):  
Ibrahim Tekin ◽  
He Yang

In this paper, the classical Euler-Bernoulli beam equation is considered by utilizing fractional calculus. Such an equation is called the time-fractional EulerBernoulli beam equation. The problem of determining the time-dependent coefficient for the fractional Euler-Bernoulli beam equation with homogeneous boundary conditions and an additional measurement is considered, and the existence and uniqueness theorem of the solution is proved by means of the contraction principle on a sufficiently small time interval. Numerical experiments are also provided to verify the theoretical findings.


2021 ◽  
Vol 6 (1) ◽  
pp. 31
Author(s):  
Camelia Avram ◽  
Jose Machado ◽  
Adina Aştilean

This paper presents a portable passwords manager which has a two-stage biometric-based access procedure. Data security using biometric methods was chosen as a variant of reduced complexity but was very effective in preventing cyber theft. The implementation of biometrics for the purpose of identification in high-security systems has become essential with the evolution of technology and the spike in identity theft. Unlike passwords or IDs, a biometric feature is an identifier that cannot be lost, stolen, or replicated, which provides biometric authentication systems with an increased level of security. During the first accessing step, the 3DPassManager portable device measures the heartbeat and uses fingerprint and iris features to realize a unique biometric-based authentication. While the specific characteristics of fingerprint and iris features are integrated to ensure that the person using the device is the rightful owner, the pulse is utilized to verify if previously acquired static images are not used. During the second accessing step, a password is generated based on fingerprint details, valid only for a small-time interval. The fingerprint is stored in a secret key with a 1024-bit length. Once access is allowed, the passwords are made available through an extension installed on the web browser. The device is the size of a cigarette pack and communicates with the PC by scanning a QR code. It is safe and was previously tested for dictionary and brute force attacks.


2018 ◽  
Vol 173 ◽  
pp. 02004
Author(s):  
Alexander Bogdanov ◽  
Alexander Degtyarev ◽  
Vasily Khramushin ◽  
Yulia Shichkina

Stages of direct computational experiments in hydromechanics based on tensor mathematics tools are represented by conditionally independent mathematical models for calculations separation in accordance with physical processes. Continual stage of numerical modeling is constructed on a small time interval in a stationary grid space. Here coordination of continuity conditions and energy conservation is carried out. Then, at the subsequent corpuscular stage of the computational experiment, kinematic parameters of mass centers and surface stresses at the boundaries of the grid cells are used in modeling of free unsteady motions of volume cells that are considered as independent particles. These particles can be subject to vortex and discontinuous interactions, when restructuring of free boundaries and internal rheological states has place. Transition from one stage to another is provided by interpolation operations of tensor mathematics. Such interpolation environment formalizes the use of physical laws for mechanics of continuous media modeling, provides control of rheological state and conditions for existence of discontinuous solutions: rigid and free boundaries, vortex layers, their turbulent or empirical generalizations.


2017 ◽  
Vol 17 (06) ◽  
pp. 1750043 ◽  
Author(s):  
Peng Luo ◽  
Ludovic Tangpi

We study the well-posedness for multi-dimensional and coupled systems of forward–backward SDEs when the generator can be separated into a quadratic and a subquadratic part. We obtain the existence and uniqueness of the solution on a small time interval. Moreover, the continuity and differentiability with respect to the initial value are presented.


2015 ◽  
Vol 30 (2) ◽  
pp. 185-211 ◽  
Author(s):  
Andrew Li ◽  
Ward Whitt ◽  
Jingtong Zhao

The modified-offered-load approximation can be used to choose a staffing function (the time-varying number of servers) to stabilize delay probabilities at target levels in multi-server delay models with time-varying arrival rates, with or without customer abandonment. In contrast, as we confirm with simulations, it is not possible to stabilize blocking probabilities to the same extent in corresponding loss models, without extra waiting space, because these probabilities necessarily change dramatically after each staffing change. Nevertheless, blocking probabilities can be stabilized provided that we either randomize the times of staffing changes or average the blocking probabilities over a suitably small time interval. We develop systematic procedures and study how to choose the averaging parameters.


2015 ◽  
Vol 74 (9) ◽  
Author(s):  
Herdawatie Abdul Kadir ◽  
M. R. Arshad ◽  
Hamed Habibi Aghdam ◽  
Munir Zaman

This paper describes a monocular visual odometry technique for low texture environment localization. Estimating the pose of a robot in a small time interval is one of the challenging problems in robotics. Localization, mapping and motion planning are three fundamental problems which directly use the pose information of the robot to achieve their goal. In this work, we extract the pose information by processing image inside a concrete culvert which is taken by a camera attached to a mobile robot. We analyze different motion scenario using correlation based image to find displacement vector between two images. Real image data from the displacement of the robot are used to demonstrate the propose method. The experimental results show that the selected method proven efficient for the in-pipe inspection robot localization.


2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Dongping Wei ◽  
Qunming Zheng ◽  
Shouwen Wen

Management of ecological tourism in protected areas faces many challenges, with visitation-related resource degradations and cultural impacts being two of them. To address those issues, several strategies including regulations, site managements, and visitor education programs have been commonly used in China and other countries. This paper presents a multiparameter stochastic differential equation model of an Ecological Tourism System to study how the populations of stakeholders vary in a finite time. The solution of Ordinary Differential Equation of Ecological Tourism System reveals that the system collapses when there is a lack of visitor educational intervention. Hence, the Stochastic Dynamic of Ecological Tourism System is introduced to suppress the explosion of the system. But the simulation results of the Stochastic Dynamic of Ecological Tourism System show that the system is still unstable and chaos in some small time interval. The Multiparameters Stochastic Dynamics of Ecological Tourism System is proposed to improve the performance in this paper. The Multiparameters Stochastic Dynamics of Ecological Tourism System not only suppresses the explosion of the system in a finite time, but also keeps the populations of stakeholders in an acceptable level. In conclusion, the Ecological Tourism System develops steadily and sustainably when land managers employ effective visitor education intervention programs to deal with recreation impacts.


Author(s):  
FRANCO FAGNOLA ◽  
VERONICA UMANITÀ

A generic quantum Markov semigroup [Formula: see text] of a d-level quantum open system with a faithful normal invariant state ρ admits a dual semigroup [Formula: see text] with respect to the scalar product induced by ρ. We show that the difference of the generators [Formula: see text] can be written as the sum of a derivation 2i[H, ⋅] and a weighted difference of automorphisms [Formula: see text] where [Formula: see text] is a family of cycles on the d levels of the system, wc are positive weights and [Formula: see text] are unitaries. This formula allows us to represent the deviation from equilibrium (in a "small" time interval) as the superposition of cycles of the system where the difference between the forward and backward evolution is written as the difference of a reversible evolution and its time reversal. Moreover, it generalises cycle decomposition of Markov jump processes. We also find a similar formula with partial isometries instead of unitaries.


2012 ◽  
Vol 22 (5) ◽  
pp. 19-26
Author(s):  
Vlad Constantin Manea ◽  
Marina Manea ◽  
Mihai Pomeran ◽  
Lucian Besutiu ◽  
Luminita Zlagnean

The problem of convective flows in a highly viscous fluid represents a common research direction in Earth sciences. For tracing the convective motion of the fluid material, a source passive particles (or tracers) that flow at a local convection velocity and do not affect the pattern of flow it is commonly used. Here we present a parallelized tracer code that uses passive and weightless particles with their position computed from their displacement during a small time interval at the velocity of flow previously calculated for a given point in space and time. The tracer code is integrated in the open source package CitcomS, which is widely used in the solid earth community (www.geodynamics.org). We benchmarked the tracer code on the state-of-the-art CyberDyn parallel machine, a High Performance Computing (HPC) Cluster with 1344 computing cores available at the Institute of Geodynamics of the Romanian Academy.


Author(s):  
Ye Ding ◽  
LiMin Zhu ◽  
XiaoJian Zhang ◽  
Han Ding

This paper presents a numerical scheme to predict the milling stability based on the integral equation and numerical integration formulas. First, the milling dynamics taking the regenerative effect into account is represented in the form of integral equation. Then, the tooth passing period is precisely divided into the free vibration phase during which the analytical solution is available and the forced vibration phase during which an approximate solution is needed. To obtain the numerical solution of the integral equation during the forced vibration phase, the time interval of interest is equally discretized. Over each small time interval, Newton-Cotes integration formulas or Gauss integration formulas are employed to approximate the integral term in the integral equation. After establishing the state transition matrix of the system in one period, the milling stability is predicted by using Floquet theory. The benchmark examples are utilized to verify the proposed approach. The results demonstrate that it is highly efficient and accurate.


Sign in / Sign up

Export Citation Format

Share Document