Search results for "VDP::Matematikk og naturvitenskap: 400::Matematikk: 410"

Exposing Empirical Links between COVID-19 Situation Report and Available Data: The Case of Nigeria

2020

Ever since the index case of COVID-19 was announced in Nigeria, the number of confirmed cases has gradually increased to 46,140 (about 4.5% of total confirmed cases in Africa) as the time of writing this article. This seemingly low number of confirmed cases has provoked heated debates among researchers. This cross-sectional study explores the Nigerian COVID-19 report to expose some links between the number of confirmed cases, testing, and some environmental conditions. The findings reveal that there is no state in Nigeria which has up to 12 confirmed cases per 10,000 population. That means, the number of confirmed COVID-19 cases is less than 0.15% of the population of people across each sta…

Asymptotic behavior of an odd-order delay differential equation

2014

Published version of an article in the journal: Boundary Value Problems. Also available from the publisher at: http://dx.doi.org/10.1186/1687-2770-2014-107 Open Access We study asymptotic behavior of solutions to a class of odd-order delay differential equations. Our theorems extend and complement a number of related results reported in the literature. An illustrative example is provided.

Themes within lecturers' views on the teaching of linear algebra

2019

Author's accepted manuscript (postprint). This is an Accepted Manuscript of an article published by Taylor & Francis in International Journal of Mathematical Education in Science and Technology on 25/09/2019, available online: http://www.tandfonline.com/10.1080/0020739X.2019.1668976. Available from 26/09/2020. This paper reports on themes that arose in an investigation of university lecturers’ views on the teaching of linear algebra. This focus on themes was the initial part of a study concentrating on four areas: What is important to teach in a first course in linear algebra? Are there teaching methods which are particularly suited for such a course? Are there tools that should/should not …

Indefinite integrals involving the exponential integral function

2021

Stability in mean of partial variables for coupled stochastic reaction-diffusion systems on networks: A graph approach

2014

Published version of an article in the journal: Abstract and Applied Analysis. Also available from the publisher at: http://dx.doi.org/10.1155/2014/597502 Open Access This paper is devoted to investigating stability in mean of partial variables for coupled stochastic reaction-diffusion systems on networks (CSRDSNs). By transforming the integral of the trajectory with respect to spatial variables as the solution of the stochastic ordinary differential equations (SODE) and using Itô formula, we establish some novel stability principles for uniform stability in mean, asymptotic stability in mean, uniformly asymptotic stability in mean, and exponential stability in mean of partial variables for…

State Estimation for Wireless Network Control System with Stochastic Uncertainty and Time Delay Based on Sliding Mode Observer

2014

Published version of an article in the journal: Abstract and Applied Analysis. Also available from the publisher at: http://dx.doi.org/10.1155/2014/303840 Open Access State estimation problem is considered for a kind of wireless network control system with stochastic uncertainty and time delay. A sliding mode observer is designed for the system under the situation that no missing measurement occurs and system uncertainty happens in a stochastic way. The observer designed for the system can guarantee the system states will be driven onto the sliding surface under control law, and the sliding motion of system states on sliding surface will be stable. By constructing proper Lyapunov-Krasovskii…

A Data-Based Approach for Modeling and Analysis of Vehicle Collision by LPV-ARMAX Models

2013

Published version of an article in the journal: Journal of Applied Mathematics. Also available from the publisher at: http://dx.doi.org/10.1155/2013/452391 Open Access Vehicle crash test is considered to be the most direct and common approach to assess the vehicle crashworthiness. However, it suffers from the drawbacks of high experiment cost and huge time consumption. Therefore, the establishment of a mathematical model of vehicle crash which can simplify the analysis process is significantly attractive. In this paper, we present the application of LPV-ARMAX model to simulate the car-to-pole collision with different initial impact velocities. The parameters of the LPV-ARMAX are assumed to …

Delay-Probability-Distribution-Dependent FIR Filtering Design with Envelope Constraints

2013

Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2013/930927 Open Access This paper studies the problem of H∞ finite-impulse response (FIR) filtering design of time-delay system. The time-delay considered here is time-varying meanwhile with a certain stochastic characteristic, and the probability of delay distribution is assumed to be known. Furthermore, the requirement of pulse-shape is also considered in filter design. Employing the information about the size and probability distribution of delay, a delay-probability-distribution-dependent criterion is proposed for the filtering error syst…

Impact of a Social Constructivist Instructional Strategy on Performance in Algebra with a Focus on Secondary School Students

2020

There have been perennial concerns on the low academic performance of students among researchers and other education stakeholders. Innovative teaching strategies have, therefore, gained prominence in the field of mathematics education. The purpose of this study is to investigate the impact of a social constructivist instructional strategy on students’ performance in algebra. The present study is quasi-experimental, and its type is a posttest control group involving 154 secondary school students that are randomly selected across four intact classes. The random selection of students to treatment and control controls is assumed to improve the validity of the results. Two research questions are…

Exploration of stationary time-series’ network properties : Visibility-and Horizontal visibility graph of Gaussian white noise, AR (1), MA (1) and AR…

2019

Master's thesis Business Administration BE501 - University of Agder 2019 We haverecordedthe network properties ofstochastic processes’whitenoise,푀퐴(1), 퐴푅(1)and 퐴푅푀퐴(1,1)bymeansof visibility-and horizontal visibility algorithms. The sample series of the stochastic processeswere artificially generated and used in simulationswith multiple repetitions. We examined six global network properties:mean degree, normalized degree centrality, degree distribution, transitivity, assortativity and average geodesic pathtodiscover how theyreflect the structure of the series. These properties were also used to disclose change in behavior due to variation in the series length.Our contribution to the literat…