IRT Approaches to Modeling Scores on Mixed-Format Tests

This article considers psychometric properties of composite raw scores and transformed scale scores on mixed-format tests that consist of a mixture of multiple-choice and free-response items. Test scores on several mixed-format tests are evaluated with respect to conditional and overall standard errors of measurement, score reliability, and classification consistency and accuracy under three item response theory (IRT) frameworks: unidimensional IRT (UIRT), simple structure multidimensional IRT (SS-MIRT), and bifactor multidimensional IRT (BF-MIRT) models. Illustrative examples are presented using data from three mixed-format exams with various levels of format effects. In general, the two MIRT models produced similar results, while the UIRT model resulted in consistently lower estimates of reliability and classification consistency/accuracy indices compared to the MIRT models.     

Orthogonal nonnegative matrix tri-factorization for co-clustering: Multiplicative updates on Stiefel manifolds

Matrix factorization-based methods become popular in dyadic data analysis, where a fundamental problem, for example, is to perform document clustering or co-clustering words and documents given a term-document matrix. Nonnegative matrix tri-factorization (NMTF) emerges as a promising tool for co-clustering, seeking a 3-factor decomposition X≈USV^?$\mathit{X}\approx {\mathit{USV}}^{?}$ with all factor matrices restricted to be nonnegative, i.e., U?0,S?0,V?0.$\mathit{U}?0\text{,}\mathit{S}?0\text{,}\mathit{V}?0\text{.}$ In this paper we develop multiplicative updates for orthogonal NMTF where X≈USV^?$\mathit{X}\approx {\mathit{USV}}^{?}$ is pursued with orthogonality constraints, U^?U=I,${\mathit{U}}^{?}\mathit{U}=\mathit{I}\text{,}$ and V^?V=I${\mathit{V}}^{?}\mathit{V}=\mathit{I}$, exploiting true gradients on Stiefel manifolds. Experiments on various document data sets demonstrate that our method works well for document clustering and is useful in revealing polysemous words via co-clustering words and documents.     

Designing a business model for financial products for cultural heritage in the Korean market

There are many contingent valuation (CV) studies to estimate the economic benefits of cultural heritage, but few provided advice on the design of financial products for cultural heritage assets. This paper conducted conjoint and willingness-to-pay (WTP) analyses for providing the design implication of these financial products. We calculated WTP for each attribute. The result of conjoint analysis shows that people prefer a short period of investment, high-expected rate of return and small amount of money invested. Only the amount invested and the rate of return on investment are significant to estimate WTP for these financial products.     

Can EFL Speakers Communicate in English-mediated Classes?: A Case of a Liberal Arts Class for Engineering Students in Korea

The purpose of this paper is twofold: (1) to explore what factors prevent English as a foreign language (EFL) students from participating in English-medium instruction classes; and (2) to examine how dialogic teaching techniques enhance students’ participation in classroom interaction. Utilizing the notions of “communicative competence” and “truncated repertoire,” we first investigated the barriers to communication in classrooms. We next examined how EFL speakers are able to communicate in English-medium instruction (EMI) classes. The findings suggest that when the instruction was designed to reduce cultural barriers and to facilitate authentic discussion, EFL students were able to participate in classroom interaction, and they perceived discussion as a way to learn an unfamiliar subject taught in English.     

Low-cost,disposable microfluidics device for blood plasma extraction using continuously alternating paramagnetic and diamagnetic capture modes

Blood plasma contains biomarkers and substances that indicate the physiological state of an organism, and it can be used to diagnose various diseases or body condition. To improve the accuracy of diagnostic test, it is required to obtain the high purity of blood plasma. This paper presents a low-cost, disposable microfluidics device for blood plasma extraction using magnetophoretic behaviors of blood cells. This device uses alternating magnetophoretic capture modes to trap and separate paramagnetic and diamagnetic cells away from blood plasma. The device system is composed of two parts, a disposable microfluidics chip and a non-disposable (reusable) magnetic field source. Such modularized device helps the structure of the disposable part dramatically simplified, which is beneficial for low-cost mass production. A series of numerical simulation and parametric study have been performed to describe the mechanism of blood cell separation in the microchannel, and the results are discussed. Furthermore, experimental feasibility test has been carried out in order to demonstrate the blood plasma extraction process of the proposed device. In this experiment, pure blood plasma has been successfully extracted with yield of 21.933% from 75 μl 1:10 dilution of deoxygenated blood.     

The impact of conflicting goals on mathematical teaching decisions

This paper describes part of an international project considering graphical construction of antiderivative functions in the secondary mathematics classroom. We use Schoenfeld’s resources, orientations, and goals (ROGs) framework to analyse the decisions made by a teacher, Adam, during a lesson on graphical antiderivatives. We present details of Adam’s ROG and see how this is related to resolution of the conflict between his competing goals and the decisions he makes. The results suggest that a beneficial professional development strategy might be to assist teachers to become more aware of their ROG and its influence on in-the-moment classroom decisions.     

Platonic and sophistic understanding of oral, literal and televisual sign as educational means

What follows is an attempt to isolate thespecificity of the new way of communication and education i.e., thetelevised image by comparing and contrasting it to the more traditional medial means,oral and literal sign. There will be several Ariadnian threads running through this labyrinth. One will be the phenomenon of self-deception: the central fear of Plato. Self-deception is to be interpreted in the widest possible sense: self-deception in relation to ourselves, to others, and our surrounding environment. Related to this will be the idea of a remedy ‘against’ that self-deception; does each medium have a remedial moment (what Plato reserved for philosophical speech)? Traditionally, we speak about three kinds of remedy: philosophical (radical reflection), scientific (the ‘objective’ point of view), and aesthetic (disinterested contemplation): what contributions do the newer mediums make? Sophistic self-deception or its remedial? What too will be a theme of this paper is how as we move from older, more familiar sorts of representations towardstelevised image, rational and educational categories falter and the specific attitude towards new images becomes more difficult to isolate.     

Demystifying Creativity: What Creativity Isn’t and Is?

To understand creativity is to recognize and develop the creative potential within oneself and others. This article examines what creativity is not and then what creativity is. First, the six leading misconceptions about creativity are discussed: Creativity belongs solely to the arts; creativity is quickly recognizable; innovators always work alone; mental illness enhances creativity; creativity is a divine flash of inspiration; and newness is a prerequisite to creativity. Then, using the research-based CATs model, what creativity is and how creativity develops into innovation are discussed: (a) cultivate creative climates; (b) nurture creative attitudes; and (c) develop creative thinking skills. Creativity does not come from nature but from nurture, and developing gifted children’s creativity should be the goal of parenting and education.