1,720,961 research outputs found
Explicit hybrid methods for solving special second order ordinary differential equations
Get PDFThe focus of this thesis is to derive new two-step explicit hybrid methods for the numerical solution of system of special second order ordinary differential equations
of the form y"=f ( x, y) . Explicit hybrid methods of order seven have been developed by employing strategies of selecting free parameters. Dissipation relations
are imposed to obtain a method with highest possible order of dissipation. Phase-lag and stability analysis are presented. Numerical results show that the methods give
better accuracy compared with the existing methods. For variable step-size codes,embedded pairs of explicit hybrid methods are introduced. The phase-lag and stability interval of the methods are given and the procedure of controlling the stepsize change is described. To improve the accuracy of hybrid methods, the construction of exponentially fitted explicit hybrid methods is investigated. The derivations of the methods with two stages and four stages are described in detail.
The method with two stages is derived for constant step-size code whereas the method with four stages is derived for variable step-size code. Their stability regions and the numerical results are given. Finally, the construction of a block explicit hybrid method implemented on a parallel computer is discussed. This method calculates two consecutive points using two independent formulas. The stability analysis of the formula which computes the second point is presented. The parallel implementation of the method is evaluated in terms of accuracy and speedup. From
the results, it is observed that the speedup is greater than 1.5 which indicates that the parallel code is faster than the sequential one. On the whole, this study reveals that the new methods are capable and efficient for solving special second order ordinary differential equations
Menjana Pemikiran Bermatematik Pelajar Pra-universiti Melalui Soalan Matematik Berbentuk Terbuka
No full textKajian ini bertujuan untuk mengenal pasti pemikiran bermatematik pelajar program pra-universiti di salah sebuah universiti di Malaysia. Pelajar diberikan tugasan yang mengandungi satu soalan penyelesaian masalah matematik berbentuk terbuka berkenaan konsep fungsi vektor. Satu jawapan terbaik yang ditulis oleh pelajar telah dipilih untuk dianalisis. Hasil daripada analisis tersebut menunjukkan bahawa pelajar menggunakan pendekatan heuristik dalam mencipta prosedur sendiri untuk mendapatkan jawapan. Ini membuktikan bahawa pemikiran bermatematik wujud di kalangan pelajar pra-universiti. Kesimpulannya, pemikiran bermatematik pelajar pra-universiti boleh digilap dengan menggunakan soalan penyelesaian matematik berbentuk terbuka dalam usaha untuk meningkatkan lagi keupayaan mereka dalam pembelajara
Diagonally implicit hybrid method for solving special second order ordinary differential equations
Get PDFThis paper describes the derivation of a fifth-order diagonally implicit hybrid method. The method is zero dissipative and has phase-lag of order six. The method is compared with the existing hybrid method and the numerical comparisons carried out show that the new method improves the accuracy of the existing method for solving several special second order ordinary differential equations
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Pre-University Students’ Perceptions towards Mathematics in the Post-pandemic Era
No full textThe Covid-19 pandemic that had begun in December 2019 had made all students in Malaysia being thrown into the online learning environment. After the prolonged home schooling, the post pandemic era that was declared in the year 2022 forced the students to attend physical classes again. This may have caused confusion among the students as they had to readapt with their old learning style once more after being comfortable with the online environment. In this research, students’ perceptions towards mathematics concerning their self-concept and achievement were explored. Participants of this study were a group of pre-university students who experienced the shift from online to physical classes in the post pandemic era. A set of questionnaires regarding the students’ perceptions was distributed to the students of the pre-university program at Universiti Kebangsaan Malaysia. The results show that 61.3% students discovered mathematics as scary despite they perceived positively on their achievement in mathematics. In conclusion, the students had moderate level of self-concept and achievement. Furthermore, there was a positive correlation between self-concept and achievement in mathematics, and there was no significant gender difference on the students’ self-concept
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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