Mathematics Commons^™

Membership Functions Or Alpha-Cuts? Algorithmic (Constructivist) Analysis Justifies An Interval Approach, Vladik Kreinovich

Departmental Technical Reports (CS)

In his pioneering papers, Igor Zaslavsky started an algorithmic (constructivist) analysis of fuzzy logic. In this paper, we extend this analysis to fuzzy mathematics and fuzzy data processing. Specifically, we show that the two mathematically equivalent representations of a fuzzy number -- by a membership function and by alpha-cuts -- are not algorithmically equivalent, and only the alpha-cut representation enables us to efficiently process fuzzy data.

Inquiry- Without Posing Questions?, Helle Alrø, Marit Johnsen-Høines

The Mathematics Enthusiast

This article discusses what inquiry conversations could mean when learning mathematics.³ Referring to Gadamar’s distinction of true and apparent questions it is discussed what it takes to be inquiring and if this attitude necessarily includes posing questions. Which qualities are expressed in inquiring questions, and what other ways of communicating may have an inquiring function in learning conversations? The intention is to develop and frame the concept of ’inquiry’ in learning conversations, and this is the focus of analysis of an authentic classroom situation, where teacher and pupils are exploring the concept of ’volume’. Further, this analysis informs a …

Investigating Engineers’ Needs As A Part Of Designing A Professional Development Program For Engineers Who Are To Become Mathematics Teachers, Ragnhild Johanne Rensaa

The Mathematics Enthusiast

The average age for teachers in mathematics and physics in Norway is about 60 (Sørensen, 2003) and few students taking a masters degree in a science subject choose a career as a teacher (KD, 2006). This implies that there may be a critical lack of science teachers in schools in the near future (Næss, 2002). At the same time, rather many graduated engineers – who have worked as engineers sometimes several years – want to contribute to the educational setting by taking part time jobs as teachers; lector-II (Vassnes, 2008). To combine this supply and demand for qualified teachers in …

The Role Of Theory When Studying Epistemological Characterizations Of Mathematics Lecture(R)S, Magnus Österholm

The Mathematics Enthusiast

The study presented in this paper is a contribution to the scientific discussion about the role and use of theory in mathematics education research. In particular, focus is here on the use of and comparison between different types of theories and frameworks, which is discussed primarily through the example of an empirical study examining what types of messages about mathematics are conveyed in lectures. The main purpose of this paper is to examine how different types of theories and frameworks can affect different parts of the research process.

Bayesian Analysis Of Hypothesis Testing Problems For General Population: A Kullback–Leibler Alternative, Naveen K. Bansal, Gholamhossein Hamedani, Ru Sheng

Mathematics, Statistics and Computer Science Faculty Research and Publications

We consider a hypothesis problem with directional alternatives. We approach the problem from a Bayesian decision theoretic point of view and consider a situation when one side of the alternatives is more important or more probable than the other. We develop a general Bayesian framework by specifying a mixture prior structure and a loss function related to the Kullback–Leibler divergence. This Bayesian decision method is applied to Normal and Poisson populations. Simulations are performed to compare the performance of the proposed method with that of a method based on a classical z-test and a Bayesian method based on the …

University Mathematics Teachers' Views On The Required Reasoning In Calculus Exams, Ewa Bergqvist

The Mathematics Enthusiast

Students often use imitative reasoning, i.e. copy algorithms or recall facts, when solving mathematical tasks. Research shows that this type of imitative reasoning might weaken the students' understanding of the underlying mathematical concepts. In a previous study, the author classified tasks from 16 final exams from introductory calculus courses at Swedish universities. The results showed that it was possible to pass 15 of the exams, and solve most of the tasks, using imitative reasoning. This study examines the teachers' views on the reasoning that students are expected to perform during their own and others mathematics exams. The results indicate that …

Tme Volume 9, Number 3

The Mathematics Enthusiast

No abstract provided.

2012 (Summer), University Of Dayton. Department Of Mathematics

Colloquia

Abstracts of the talks given at the 2012 Summer Colloquium.

The Weak Discrepancy And Linear Extension Diameter Of Grids And Other Posets, Katherine Victoria Johnson

Department of Mathematics: Dissertations, Theses, and Student Research

A linear extension of a partially ordered set is simply a total ordering of the poset that is consistent with the original ordering. The linear extension diameter is a measure of how different two linear extensions could be, that is, the number of pairs of elements that are ordered differently by the two extensions. In this dissertation, we calculate the linear extension diameter of grids. This also gives us a nice characterization of the linear extensions that are the farthest from each other, and allows us to conclude that grids are diametrally reversing.

A linear extension of a poset might …

General Allee Effect In Two-Species Population Biology, G Livadiotis, Saber Elaydi

Mathematics Faculty Research

The main objective of this work is to present a general framework for the notion of the strong Allee effect in population models, including competition, mutualistic, and predator–prey models. The study is restricted to the strong Allee effect caused by an inter-specific interaction. The main feature of the strong Allee effect is that the extinction equilibrium is an attractor. We show how a ‘phase space core’ of three or four equilibria is sufficient to describe the essential dynamics of the interaction between two species that are prone to the Allee effect. We will introduce the notion of semistability in planar …

Beyond Post-Modernity In Mathematics Education, Ole Skovsmose

The Mathematics Enthusiast

A radical form of postmodernity is presented with reference to Nietzsche’s ideas with respect to truth, knowledge, sciences, progress, democracy, and ethical values in general. Thereafter is presented Foucault’s archaeology of knowledge. This brings us forward to the notion of genealogy, which is a defining idea for the postmodern conception of critique. However, it is emphasised that a critique can address the generativity of mathematical rationality by considering mathematics-based fabrications. Finally, imagination is presented as yet another feature of a critical enterprise. It is illustrated how such a three dimensional critical enterprise is relevant for both mathematics and mathematics education. …

Loss Of Dimension In The History Of Calculus And In Student Reasoning, Robert Ely

The Mathematics Enthusiast

Research indicates that calculus students often imagine objects losing a dimension entirely when a limit is taken, and that this image serves as an obstacle to their understanding of the fundamental theorem of calculus. Similar imagery, in the form of “indivisibles”, was similarly unsupportive of the development of the fundamental theorem in the mid-1600s, unlike the more powerful subsequent imagery of infinitesimals. This parallel between student issues and historical issues suggests several implications for how to provide students with imagery that is more productive for understanding the fundamental theorem, such as the imagery of infinitesimals or the more modern quantitative …

Demographics Of Self-Selected Participants In Mathematical Tracks In Swedish Upper Secondary School, Linda Mattsson

The Mathematics Enthusiast

This study investigates the three demographic factors gender, geographical origin and parents educational level among self-selected students in mathematical tracks in Swedish Upper Secondary School (n=147). Comparisons are made, through statistical tests of significance, with corresponding student distributions on the closely related Natural Science program (n = 1528). Data is obtained from Statistics Sweden. Results confirm that females are under-represented in mathematical tracks (p<0,01) and that parents of students in mathematical tracks have higher educational level than parents of students in the comparison group (p<0,05). Results do not show that students with foreign background are underrepresented in mathematical tracks, but raise questions about under-representation of Swedish students. Possible implications of these findings for these and similar programs are discussed.

Foundations For Success In Mathematical Competitions: A Study Of Best Praxis In Lower Secondary Schools In Norway, Steinar Thorvaldsen, Lars Vavik

The Mathematics Enthusiast

The purpose of this study is to investigate the following questions: What factors leads to success in mathematics, and how can these success factors and qualities be described? Will the teacher’s education and pedagogical praxis have an impact on good learning results? We report results from a case-control association study on among high achievement classes in mathematics in Norway. The data were collected from matched pairs of schools, paired on the basis of location and socioeconomic status. The questionnaire was first distributed to teachers in 38 Norwegian secondary schools at grade 9, which have had repeated success in the annual …

From Designing To Implementing Mathematical Tasks: Investigating The Changes In The Nature Of The T-Shirt Task, Claire Vaugelade Berg

The Mathematics Enthusiast

From looking at research literature it is possible to see that research on design, implementation and analysis of mathematical tasks is an actual theme: there is a special issue of the Journal of Mathematics Teacher Education (2007) with Anne Watson, John Mason and Orit Zaslavsky as editors (Watson and Mason, 2007), a book published by Clarke, Grevholm and Millman (2009) concerning “Tasks in primary mathematics teacher education” and under ICME 11 in Mexico (2008) the title of one of the Topic Study Groups was “Research and development in task design and analysis”. In addition several substantial research projects conducted in …

Values In Effective Mathematics Lessons In Sweden: What Do They Tell Us?, Aihui Peng, Mikaela Nyroos

The Mathematics Enthusiast

This study aims to examine values in effective mathematics lessons in Sweden from the perspectives of students in different groups and their teachers. By using methods with lesson observations, student focus group interviews and teacher interviews, it shows that instructional explanation and classroom atmosphere with quietness are shared-values of students and their teachers. The findings propose some crucial issues which related to how mathematics teaching could be adjusted to different students’ learning conditions and whether it needs more instructional explanation in mathematics teaching in Sweden.

Evaluating Mersenne Primes Using A Single Quadrant Expanding Square, Cory P. Daignault, Douglas Sprague, Joe L. Mott

The Mathematics Enthusiast

By forming a table of sequential odd numbers using a single quadrant expanding square pattern it was observed that multiple Mersenne primes fall into the first column. We prove that the Mersenne primes which fall into the first column will be of the form p = 3 mod 4, where p is the Mersenne prime exponent. Focusing the search of primes to those which fall into the first column of this square may be a means to increase the speed at which large primes are discovered.

Some Unified Results On Comparing Linear Combinations Of Independent Gamma Random Variables, Subhash C. Kochar, Maochao Xu

Mathematics and Statistics Faculty Publications and Presentations

In this paper, a new sufficient condition for comparing linear combinations of independent gamma random variables according to star ordering is given. This unifies some of the newly proved results on this problem. Equivalent characterizations between various stochastic orders are established by utilizing the new condition. The main results in this paper generalize and unify several results in the literature including those of Amiri, Khaledi, and Samaniego [2], Zhao [18], and Kochar and Xu [9].

Generalized Diamond-Alpha Dynamic Opial Inequalities, Nuriye Atasever, Billûr Kaymakçalan, Goran Lesaja, Kenan Taş

Mathematical Sciences: Faculty Publications

We establish some new dynamic Opial-type diamond alpha inequalities in time scales. Our results in special cases yield some of the recent results on Opial's inequality and also provide new estimates on inequalities of this type. Also, we introduce an example to illustrate our result.

Response Surface Optimization Of Electron Beam Freeform Fabrication Depositions Using Design Of Experiments, Patricia A. Quigley

Engineering Management & Systems Engineering Theses & Dissertations

The Electron Beam Freeform Fabrication (EBF³ ) System is a material depositing, layer additive technique that produces three dimensional (3D) parts out of a wide range of metals in high vacuum, using an electron beam and wire feedstock. Screening deposition trials on a titanium alloy, Ti-6Al-4V, at the National Aeronautics Space Administration (NASA) revealed selective vaporization of the aluminum content of linear prototypes when subjected to chemical analysis. In this study, the aluminum content, bead height and bead width output responses were analyzed from a systematic study of the effects that the interactions of the EBF³ processing parameters …

Numerical Analysis And Design Optimization Of Organic Bulk Hetero-Junction Solar Cells Using The Mixed Finite Element And Arc-Length Methods, James L. Dean

Mechanical & Aerospace Engineering Theses & Dissertations

Due to the high coupling and non-linear nature of the semiconductor equations, numerical stability becomes a major problem when using a purely Newtonian numerical method in solving these equations. Presented is a robust mixed finite element formulation with application for organic solar cell devices that incorporates the arc-length predictor-corrector method to bypass such stability issues. The simulated device represents a multilayered solar cell using organic bulk hetero-junction materials including donor materials Poly[2,1,3-benzothiadiazole-4,7-diyl[4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b:3,4- b']dithiophene-2,6-diyl]] (PCPDTBT) and poly 3-hexylthiophene (P3HT) with acceptor fullerene materials [6,6]-phenyl C61 butyric acid methyl ester (PC61BM) or [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) as the photoactive …

Extended Pcr Rules For Dynamic Frames, Florentin Smarandache, Jean Dezert

Branch Mathematics and Statistics Faculty and Staff Publications

In most of classical fusion problems modeled from belief functions, the frame of discernment is considered as static. This means that the set of elements in the frame and the underlying integrity constraints of the frame are fixed forever and they do not change with time. In some applications, like in target tracking for example, the use of such invariant frame is not very appropriate because it can truly change with time. So it is necessary to adapt the Proportional Conflict Redistribution fusion rules (PCR5 and PCR6) for working with dynamical frames. In this paper, we propose an extension of …

Experimental And Computational Validation And Verification Of The Stokes-Darcy And Continuum Pipe Flow Models For Karst Aquifers With Dual Porosity Structure, Xiaolong Hu, Xiaoming Wang, Max Gunzburger, Fei Hua, Yanzhao Cao

Mathematics and Statistics Faculty Research & Creative Works

In our previous study, we developed the Stokes-Darcy (SD) model was developed for flow in a karst aquifer with a conduit bedded in matrix, and the Beavers-Joseph (BJ) condition was used to describe the matrix-conduit interface. We also studied the mathematical well-posedness of a coupled continuum pipe flow (CCPF) model as well as convergence rates of its finite element approximation. in this study, to compare the SD model with the CCPF model, we used numerical analyses to validate finite element discretisation methods for the two models. using computational experiments, simulation codes implementing the finite element discretisations are then verified. Further …

Clark, William B., B. 1797? (Sc 632), Manuscripts & Folklife Archives

Manuscript Collection Finding Aids

Finding aid and one scanned page (Click on "additional files" below) for Manuscripts Small Collection 632. Ciphering book kept by William B. Clark of Christian County, Kentucky, 25 August 1813 to 22 August 1814, and intermittently by others to 1819. Other entries include business accounts of Clark, a blacksmith, and family genealogy. The book was bound
with sheets from the Western Eagle, a newspaper printed in Hopkinsville, Kentucky, and dated 12 February 1813. It was removed and added to the Special Collections Library. A loose item found in the book, 1834-1846, contains accounts of Clark.

Fixed Point Theorems For Convex-Power Condensing Operators Relative To The Weak Topology And Applications To Volterra Integral Equations, Ravi P. Agarwal, Donal O'Regan, Mohamed-Aziz Taoudi

Mathematics and System Engineering Faculty Publications

In this paper we present new fixed point theorems for weakly sequentially continuous mappings which are convex-power condensing relative to a measure of weak noncompactness. Our fixed point results extend and improve several earlier works. As an application, we investigate the existence of weak solutions to a Volterra integral equation. 2012 Rocky Mountain Mathematics Consortium.

Cearnal, Elijah (Sc 588), Manuscripts & Folklife Archives

Manuscript Collection Finding Aids

Finding aid and scan (Click on "additional files" below) for Manuscripts Small Collection 588. A ciphering book kept by Elijah Cearnal as a student. The name "Patrick Carnall" is also written in the book.

Wilkerson, Brice W. (Sc 586), Manuscripts & Folklife Archives

Manuscript Collection Finding Aids

Finding aid and scan (Click on "additional files" below) for Manuscripts Small Collection 586. A ciphering book kept by Brice W. Wilkerson, of either Simpson County of Logan County, Kentucky, as a student. The name “Stanley Wilkerson” is also noted in the book.

Sutherland, Daniel, 1797-1835 (Sc 589), Manuscripts & Folklife Archives

Manuscript Collection Finding Aids

Finding aid and scan (Click on "additional files" below) for Manuscripts Small Collection 589. Ciphering book of Daniel Sutherland, probably of Casey County, Kentucky, dated 31 March 1825 to 2 December 1825. It was also used for the period from 16 July 1828 to 9 October 1828, and indications are that this record was the work of Uriah S. Sutherland.

Motley, Matthew, 1786-1845 (Sc 591), Manuscripts & Folklife Archives

Manuscript Collection Finding Aids

Finding aid and scan (Click on "additional files" below) for Manuscripts Small Collection 591. Ciphering book, 1800-1801, kept by Matthew Motley of Allen County, Kentucky. Business accounts,1807-1811, of John Motley, father of Matthew, and business accounts, 1805-1823, of Matthew, who was a cabinetmaker, are documented in the back of the book; other notations record the hiring out of enslaved persons, medicinal remedies, and a poetic reaction to the New Madrid earthquake, 1811.

Smith, Alexander (Sc 596), Manuscripts & Folklife Archives

Manuscript Collection Finding Aids

Finding aid and scan (Click on "additional files" below) for Manuscripts Small Collection 596. Ciphering book, 1799, made by Alexander Smith, who was a school master in Prince George County, Virginia. Henry Oiler? states that it is his ciphering book, so perhaps he was a student of
Smith’s. A few business accounts of Oiler’s are recorded.