Opinions on computing education in Korean K-12 system: higher education perspective

The need for computing education in the K-12 curriculum has grown globally. The Republic of Korea is not an exception. In response to the need, the Korean Ministry of Education has announced an outline for software-centric computing education in the K-12 system, which aims at enhancing the current computing education with software emphasis. In this paper, we review the outline from a higher education perspective and provide insights into its constructive improvement based on our experience in computer science education in higher education and a study of global initiatives on computing education. We also consider the social environment for computing education in Korea. In the proposed implementation, we first discuss goals for software-centric computing education and identify areas of focus. The identified areas are discussed in terms of topics to be covered and appropriate exposure of knowledge depth in the three levels in the Korean K-12 system. We then discuss necessary preparations for the success of the plan from academic, governmental and social perspectives.     

Measurement Invariance Testing Across Between-Level Latent Classes Using Multilevel Factor Mixture Modeling

This simulation study examines the efficacy of multilevel factor mixture modeling (ML FMM) for measurement invariance testing across unobserved groups when the groups are at the between level of multilevel data. To this end, latent classes are generated with class-specific item parameters (i.e., factor loading and intercept) across the between-level classes. The efficacy of ML FMM is evaluated in terms of class enumeration, class assignment, and the detection of noninvariance. Various classification criteria such as Akaike’s information criterion, Bayesian information criterion, and bootstrap likelihood ratio tests are examined for the correct enumeration of between-level latent classes. For the detection of measurement noninvariance, free and constrained baseline approaches are compared with respect to true positive and false positive rates. This study evidences the adequacy of ML FMM. However, its performance heavily depends on the simulation factors such as the classification criteria, sample size, and the magnitude of noninvariance. Practical guidelines for applied researchers are provided.     

Student‐generated analogies: Another way of knowing?

Recently, a growing awareness of the relationship between assessment and learning has resulted in several major critiques of existing practice and proposals for reform in science education at national and regional levels. One initiative advocates the use of carefully constructed performance tasks that give students opportunities to demonstrate their understanding as they would in the world outside of school. The purpose of this study was to explore relationships among school students' (n = 189) acquisition of meaningful understandings of protein synthesis. Students were tested before and after protein synthesis instruction using a multiple choice assessment format and an open‐ended assessment format. The assessment instrument was designed to measure students' interrelated understanding of protein synthesis. An independent t‐test analysis was conducted on the posttests to measure retention of factual information and gender differences. Analysis of student‐generated analogies also revealed unique patterns in students' understandings of this topic. This research provides information for educators on students' acquisition of meaningful understandings of protein synthesis and has many implications for educators. © 1999 John Wiley & Sons, Inc. J Res Sci Teach 36: 1–22, 1999.     

Latent class analysis of non-formal learners’ self-directed learning patterns in open educational resource repositories

Open educational resources (OERs) are increasingly adopted in non-formal education contexts. However, little research has been conducted to investigate the self-directed learning patterns of non-formal learners using OERs. A lack of knowledge about non-formal learners precludes discussions on how to support their self-regulated learning in open learning environments. We explored the self-directed learning patterns of 1892 non-formal online learners who were using OER repositories. In addition, we examined whether differences existed in future intentions to use OERs between learners with different learning patterns. Four latent classes were identified, and learners’ age was found to affect class membership. We also found that non-formal learners’ use of self-directed learning strategies predicted their future intentions to use OERs. This study advanced our understanding of the subpopulations of non-formal learners using OERs. Future research will benefit from the findings related to designing OER environments that can accommodate diverse self-directed learners.     

Density-dependent separation of encapsulated cells in a microfluidic channel by using a standing surface acoustic wave

This study presents a method for density-based separation of monodisperse encapsulated cells using a standing surface acoustic wave (SSAW) in a microchannel. Even though monodisperse polymer beads can be generated by the state-of-the-art technology in microfluidics, the quantity of encapsulated cells cannot be controlled precisely. In the present study, mono-disperse alginate beads in a laminar flow can be separated based on their density using acoustophoresis. A mixture of beads of equal sizes but dissimilar densities was hydrodynamically focused at the entrance and then actively driven toward the sidewalls by a SSAW. The lateral displacement of a bead is proportional to the density of the bead, i.e., the number of encapsulated cells in an alginate bead. Under optimized conditions, the recovery rate of a target bead group (large-cell-quantity alginate beads) reached up to 97% at a rate of 2300 beads per minute. A cell viability test also confirmed that the encapsulated cells were hardly damaged by the acoustic force. Moreover, cell-encapsulating beads that were cultured for 1 day were separated in a similar manner. In conclusion, this study demonstrated that a SSAW can successfully separate monodisperse particles by their density. With the present technique for separating cell-encapsulating beads, the current cell engineering technology can be significantly advanced.     

Roles of alternative and self-oriented perspectives in the context of the continued use of social network sites

Individuals with a positive evaluation of a target system are likely to continue using the system, and this sustained use is likely to result in continued use. This target-oriented perspective has served as a major conceptual framework for understanding users’ behaviors in online contexts. The primary objective of this paper is to address two additional perspectives—alternative- and self-oriented perspectives—for a firmer understanding of continued use in the context of social network sites (SNS). A research model is built by employing regret and self-image congruity to represent these two perspectives. The model also examines the condition under which habits are formed and how this automatic mechanism influences the dynamics of the nomological network between intentions and behaviors. The analysis results of two rounds of surveys for capturing the actual link between intentions and behaviors indicate that regret and self-image congruity can play crucial roles in post-adoption phenomena in the context of SNS.     

Korean elementary school students’ English learning demotivation: a comparative survey study

This study explores Korean elementary school students’ decreased motivation for English learning by analyzing the questionnaire data obtained from 6,301 students in a large city in South Korea. The students’ school grades and their prior experience in private institutes were considered as the major factors behind the decrease in their motivation. There was a statistically significant and consistent decrease in the students’ satisfaction with their English learning experience; expectation of ultimate success in English; and intrinsic/extrinsic motivation and integrative/instrumental motivation. Prior experience in attending private institutes had a substantial impact on the students’ motivation. Those who attended private institutes (hakwons) exhibited higher levels of instrumental and intrinsic motivation. However, in terms of other motivational constructs of integrative and extrinsic (parental, academic) motivation, private instruction had a negligible or negative impact. By comparing the results with those of Lamb (2007), the present study proposes that Korean students should be made to internalize the beneficial role played by English so that their English learning motivation can be maintained.     

Investigating Stage-Sequential Growth Mixture Models with Multiphase Longitudinal Data

This article investigates three types of stage-sequential growth mixture models in the structural equation modeling framework for the analysis of multiple-phase longitudinal data. These models can be important tools for situations in which a single-phase growth mixture model produces distorted results and can allow researchers to better understand population heterogeneity and growth over multiple phases. Through theoretical and empirical comparisons of the models, the authors discuss strategies with respect to model selection and interpreting outcomes. The unique attributes of each approach are illustrated using ecological momentary assessment data from a tobacco cessation study. Transitional discrepancy between phases as well as growth factors are examined to see whether they can give us useful information related to a distal outcome, abstinence at 6 months postquit. It is argued that these statistical models are powerful and flexible tools for the analysis of complex and detailed longitudinal data.     

On the construction of cryptographically strong Boolean functions with desirable trade-off

INTRODUCTION A variety of desirable criteria for functions have been identified: balancedness, local and global ava-lanche characteristics, high nonlinearity, etc. These properties are also very important for cryptographic purpose. Obtaining optimal tradeoffs among so many properties is hard. If we take into account more crite-ria, it is more difficult to generate Boolean functions satisfying those properties purely by constructive algebraic methods. How to construct Boolean func-tions …     

Differential Item Functioning in Biodata: Opportunity Access as an Explanation of Gender- and Race-Related DIF

Investigations of differential item functioning (DIF) have been conducted mostly on ability tests and have found little evidence of easily interpretable differences across various demographic subgroups. In this study, we examined the degree to which DIF in biographical data items referencing academically relevant background, experiences, and interests was related to differences in judgments about access to these experiences by members of different gender and race subgroups. DIF in the location parameter was significantly related (r = –.51, p < .01) to gender differences in perceived accessibility to experience. No significant relationships with accessibility were observed for DIF in the slope parameter across gender groups or for the slope and location parameters associated with DIF across Black and White groups. Practical implications for use of biodata and theoretical implications for DIF research are discussed.