Search results for "Method"
showing 10 items of 13253 documents
Optimal Guard Placement Problem Under L-Visibility
2006
Two points a and b in the presence of polygonal obstacles are L-visible if the length of the shortest path avoiding obstacles is no more than L. For a given convex polygon Q, Gewali et al [4]. addressed the guard placement problem on the exterior boundary that will cover the maximum area exterior to the polygon under L-visibility. They proposed a linear time algorithm for some given value of L. When the length L is greater than half of the perimeter, they declared that problem as open. Here we address that open problem and present an algorithm whose time complexity is linear in number of vertices of the polygon.
International Education Studies: Increasing Their Linguistic Comparability by Developing Judgmental Reviews
2012
In international education studies, the different-language test versions need to be equally difficult to read and answer for the test to be valid. To ensure comparability, several quality control procedures have been developed. Among these, surprisingly little attention has been paid to judgmental reviews and their ability to identify language-related sources of bias. Also, the reviews have often failed in identifying biases. This paper explored whether it is possible to improve the ability of judgmental reviews to identify language-related sources of bias. A new review was made of two Finnish items which in the PISA (Programme for International Student Assessment) 2000 reading test showed …
Qualitative Analysis of Differential, Difference Equations, and Dynamic Equations on Time Scales
2015
and Applied Analysis 3 thank Guest Editors Josef Dibĺik, Alexander Domoshnitsky, Yuriy V. Rogovchenko, Felix Sadyrbaev, and Qi-Ru Wang for their unfailing support with editorial work that ensured timely preparation of this special edition. Tongxing Li Josef Dibĺik Alexander Domoshnitsky Yuriy V. Rogovchenko Felix Sadyrbaev Qi-Ru Wang
The Exponential Dichotomy under Discretization on General Approximation Scheme
2011
This paper is devoted to the numerical analysis of abstract parabolic problem 𝑢 ( 𝑡 ) = 𝐴 𝑢 ( 𝑡 ) ; 𝑢 ( 0 ) = 𝑢 0 , with hyperbolic generator 𝐴 . We are developing a general approach to establish a discrete dichotomy in a very general setting in case of discrete approximation in space and time. It is a well-known fact that the phase space in the neighborhood of the hyperbolic equilibrium can be split in a such way that the original initial value problem is reduced to initial value problems with exponential decaying solutions in opposite time direction. We use the theory of compact approximation principle and collectively condensing approximation to show that such a decomposition o…
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…
RTS2 - the Remote Telescope System
2010
RTS2 is an open source observatory manager. It was written from scratch in the C++ language, with portability and modularity in mind. Its driving requirements originated from quick follow-ups of Gamma Ray Bursts. After some years of development it is now used to carry tasks it was originally not intended to carry. This article presents the current development status of the RTS2 code. It focuses on describing strategies which worked as well as things which failed to deliver expected results. Copyright © 2010 Petr Kubánek.
Intraocular Telescopic System Design: Optical and Visual Simulation in a Human Eye Model
2016
Purpose. To design an intraocular telescopic system (ITS) for magnifying retinal image and to simulate its optical and visual performance after implantation in a human eye model. Methods. Design and simulation were carried out with a ray-tracing and optical design software. Two different ITS were designed, and their visual performance was simulated using the Liou-Brennan eye model. The difference between the ITS was their lenses’ placement in the eye model and their powers. Ray tracing in both centered and decentered situations was carried out for both ITS while visual Strehl ratio (VSOTF) was computed using custom-made MATLAB code. Results. The results show that between 0.4 and 0.8 mm of d…
A filtering algorithm for maneuvering target tracking based on smoothing spline fitting
2014
Published version of an article in the journal: Abstract and Applied Analysis. Also available from the publisher at: http://dx.doi.org/10.1155/2014/127643 Open Access Maneuvering target tracking is a challenge. Target's sudden speed or direction changing would make the common filtering tracker divergence. To improve the accuracy of maneuvering target tracking, we propose a tracking algorithm based on spline fitting. Curve fitting, based on historical point trace, reflects the mobility information. The innovation of this paper is assuming that there is no dynamic motion model, and prediction is only based on the curve fitting over the measured data. Monte Carlo simulation results show that, …
Collecting and Using Students’ Digital Well-Being Data in Multidisciplinary Teaching
2018
This article examines how students (N=198; aged 13 to 17) experienced the new methods for sensor-based learning in multidisciplinary teaching in lower and upper secondary education that combine the use of new sensor technology and learning from self-produced well-being data. The aim was to explore how students perceived new methods from the point of view of their learning and did the teaching methods provide new information that could promote their own well-being. We also aimed to find out how to collect digital well-being data from a large number of students and how the collected big data set can be utilized to predict school success from the students’ well-being data by using machine lear…
Fuzzy C-Means Segmentation on Brain MR Slices Corrupted by RF-Inhomogeneity
2007
Brain MR Images corrupted by RF-Inhomogeneity exhibit brightness variations in such a way that a standard Fuzzy C-Means (fcm) segmentation algorithm fails. As a consequence, modified versions of the algorithm can be found in literature, which take into account the artifact. In this work we show that the application of a suitable pre-processing algorithm, already presented by the authors, followed by a standard fcm segmentation achieves good results also. The experimental results ones are compared with those obtained using SPM5, which can be considered the state of the art algorithm oriented to brain segmentation and bias removal.