• Journal of Korean language education
• /
• v.29 no.1
• /
• pp.163-197
• /
• 2018

The present study suggests ways to improve the Korean proficiency screening test through an analysis of WIDA tests. A review of WIDA Screener, WIDA MODEL, and W-APT reveals that each of these three tests consists of four or five tests, corresponding to grade-level clusters. In addition, the WIDA screening tests assess both English for social communication and academic English, according to WIDA's five English Language Development (ELD) standards. Thematic folders of the ELD standards have different ranges of item difficulty, and the WIDA screening tests are adaptive tests. Lastly, the writing tests consist of performance-based tasks, and the rubric is holistic. As suggestions for improvement for Korean screening tests of the KSL curriculum, this study proposes (a) to devise items to assess academic Korean, so as to evaluate students' overall proficiency more accurately, (b) to utilize an adaptive method to screen students' proficiency more efficiently, and (c) to revise the writing tasks and rubric of the current KSL screening tests.

• Structural Engineering and Mechanics
• /
• v.40 no.2
• /
• pp.257-277
• /
• 2011

In this paper the geometrically nonlinear continuum plate finite element model, hitherto not reported in the literature, is developed using the total Lagrange formulation. With the layerwise displacement field of Reddy, nonlinear Green-Lagrange small strain large displacements relations (in the von Karman sense) and linear elastic orthotropic material properties for each lamina, the 3D elasticity equations are reduced to 2D problem and the nonlinear equilibrium integral form is obtained. By performing the linearization on nonlinear integral form and then the discretization on linearized integral form, tangent stiffness matrix is obtained with less manipulation and in more consistent form, compared to the one obtained using laminated element approach. Symmetric tangent stiffness matrixes, together with internal force vector are then utilized in Newton Raphson's method for the numerical solution of nonlinear incremental finite element equilibrium equations. Despite of its complex layer dependent numerical nature, the present model has no shear locking problems, compared to ESL (Equivalent Single Layer) models, or aspect ratio problems, as the 3D finite element may have when analyzing thin plate behavior. The originally coded MATLAB computer program for the finite element solution is used to verify the accuracy of the numerical model, by calculating nonlinear response of plates with different mechanical properties, which are isotropic, orthotropic and anisotropic (cross ply and angle ply), different plate thickness, different boundary conditions and different load direction (unloading/loading). The obtained results are compared with available results from the literature and the linear solutions from the author's previous papers.

• Structural Engineering and Mechanics
• /
• v.85 no.4
• /
• pp.445-459
• /
• 2023

The current investigation is the first endeavor to apply the full layerwise finite element method (FEM) in free vibration analysis of functionally graded (FG) composite plates reinforced with graphene nanoplatelets (GPLs) in thermal environment. Unlike the equivalent single-layer (ESL) theories, the layerwise FEM focuses on all three-dimensional (3D) effects. The GPLs weight fraction is presumed invariable in each layer but varies through the plate thickness in a layerwise model. The modified Halpin-Tsai model is employed to acquire the effective Young's modulus. The rule of mixtures is applied to specify the effective Poisson's ratio and mass density. First, the current method is validated by comparing the numerical results with those stated in the available works. Next, a thorough numerical study is performed to examine the influence of various factors involving the pattern of distribution, weight fraction, geometry, and size of GPLs, together with the thickness-to-span ratio, thermal environment, and boundary conditions of the plate, on its free vibration behaviors. Numerical results demonstrate that employing a small percentage of GPL as reinforcement considerably grows the natural frequencies of the pure epoxy. Also, distributing more square-shaped GPLs, involving a smaller amount of graphene layers, and vicinity to the upper and lower surfaces make it the most efficient method to enhance the free vibration behaviors of the plate.

• Journal of English Language & Literature
• /
• v.58 no.6
• /
• pp.1085-1101
• /
• 2012

This study, guided by Engeström's (1999, 2001) activity theory which owes its theoretical lineage to sociocultural theory, explores how roles (peer feedback givers and receivers) and tasks are distributed among EFL students who engage in peer response. More specifically, as an extension of previous research of focusing on "stances" ESL students adopt, I investigate whether different roles in peer response groups make a difference in the nature of peer response and identify what underlays the different roles in peer group interaction. In addition, I examine whether different roles to the peer response create tensions and contradictions in peer response and how these created conflicts lead to changes in peer response activity system. The data I wish to consider is first-person narratives elicited from two EFL college students. I use Won's and Choi's (both pseudonyms) stories as a heuristic, which is a method that allowing one to proceed fruitfully in finding information. Foregrounded in this study are the students' different roles in the same peer response activity. A division of labor exists between Won/Choi and their peers - the way tasks are divided up and the way roles are structured. Yet Won and Choi adopted rather divergent roles when participating in peer response activity and carried out qualitatively different peer response activities. It is obvious here that the distribution of their roles in carrying out this particular peer response is shaped by Won' and Choi's perception about the validity of their peers' responses.

• Proceedings of the Korean Society of Developmental Biology Conference
• /
• 2003.10a
• /
• pp.60-60
• /
• 2003

Embryonic stem (ES) cells have property of self-renewal and can differentiate into the cells of all three primary germ layers. Recently, many growth factors, alteration of culture condition and gene modifications have been used to differentiate mouse and human ES cells into specific cell types. This study was performed to evaluate the differentiation protocol for human ES cells to the endodermal lineage cells. Human ES cells (Miz-hESl ) were cultured on STO feeder layer mitotically inactivated with mitemycin C, and embryoid bodies (EBs) were formed by suspension culture. Differentiation protocol of EBs consisted of three steps: stage I, culture of EBs for 6 days with ITSFn medium; stage II, culture of stage I cells for 8 days with N2 medium ; stage III, culture of stage II cells for 22 days with N2 medium. mRNA levels of the endodermal lineage differentiation genes were analyzed by semi- quantitative RT-PCR. The Oct-4 expression, a marker of the pluripotent state, was detected in undifferentiated human ES cells but progressively decreased after EBs formation. Differentiating human ES cells expressed marker genes of endodermal differentiation and pancreatic islet cells. GATA4, a-fetoprotein, Glut-2, and Ngn3 were expressed in all stages. However, albumin and insulin were expressed in only stage III cells. The human ES cells can be differentiated into endodermal lineage cells by multiple step culture system using various supplements. We are developing the more effective protocols for guided differentiation of human ES cells.

• The Journal of the Korea Contents Association
• /
• v.18 no.8
• /
• pp.157-165
• /
• 2018

The purpose of this study is to investigate the effectiveness of general use of English literary works. It will be helpful for both general English learners and college students majoring English Education in ESL or EFL context. English literature is very useful pedagogical tool in the language class due to its unique valuable characteristics including authenticity, cultural and linguistic value, and personal enrichment, which impact on fostering English ability of EFL students. For this reason, it is unavoidable to develop a theory and practice regarding using English literature as an educational resource for college students in Korea. In this study several considerations will be discussed in terms of selection of the literary works to be applied for language learning purpose in the classrooms of universities in Korea. Such attentions will include fours skills of English such as reading, writing, listening and speaking. Finally, some effects and implications of using literary text as a pedagogical tool in the EFL language classrooms will be discussed.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.22 no.3
• /
• pp.267-275
• /
• 2009

This paper presents the p-convergent coupling element on the basis of the ESSE(equivalent single layer shell element) and the PLLE(partial-linear layerwise element) to analyze laminated composite plates. The ESSE is formulated by the degenerated shell theory, on the other hand, the assumption of the PLLE is piecewise linear variation of the in-plane displacement and a constant value of lateral displacement across the thickness. The proposed finite element model is based on p-convergence approach. The integrals of Legendre polynomials and Gauss-Lobatto technique are chosen to interpolate displacement fields and to implement numerical quadrature, respectively. This study has been focused on the verification of p-convergent element. For this purpose, various finite element multiple models associated with the combination of ESSE and PLLE elements are tested to show numerical stability. The simple examples such as a cantilever beam subjected vertical load and a plate with tension are adopted to evaluate the performance of proposed element.

• English Language & Literature Teaching
• /
• no.3
• /
• pp.141-183
• /
• 1997

This paper aims to find out the current state of early English education in the world(including Korea) and to suggest its more desirable direction, with special reference to TEFL in elementary schools of Korea. In fact English teaching in elementary schools of Korea has been put into practice as an extracurricular activity since 1982. But in 1995 the Ministry of Education proclaimed a policy to establish a TEFL program as the regular course in elementary schools of Korea since 1997. In this connection, the writer surveyed several kinds of theories about early English education to verify the necessity and validity of Korea's elementary school English education. The logical result from these theories is that younger children are better equipped to learn foreign languages with efficiency than older children or adults. However, as most studies are based on logical inferences rather than on direct observation or experimental evidence, we are not sure that those theories are right. In this view, the writer put stress on the preparation of educational environments to establish a more desirable direction of early English education in Korea, since Korea's elementary school English education will be practiced under EFL environment, not ESL environment. The writer also pointed out some problems of educational finances, the curriculum development process and its content, teaching materials(textbooks and tapes), English teachers, teaching methods, evaluation, educational facilities. This paper concludes that we have to try to solve these problems to succeed in a TEFL program in elementary schools of Korea and suggests several things for a more desirable direction of Korea's elementary school English education.

• Korean Journal of Cognitive Science
• /
• v.18 no.3
• /
• pp.255-284
• /
• 2007

This study explored the ESL college learners' perceptions on integrating reading and writing in the context of the reading-to-write composition classroom. Using the panel survey (N=60) that repeatedly measured the same set of individuals at three different times during a semester, this study examined whether students' perceptions on reading-writing integrations were reshaped over the course of classroom practices. The survey instrument was developed to assess the perception scores from less integrative continua to more integrative continua on a 5-point Likert scale. A two-factor ANOVA with repeated measures was performed to evaluate mean differences across the perception groups and over the three treatment times. The results do not demonstrate a significant treatment effect, suggesting that L2 learners' integrative perceptions were stable over the course of the semester. The dynamics in the perception changes differed widely across the perception groups. This result provides insights into understanding students' reading-writing practices and thus into instructional practices applicable to the classrooms. The present study argues for 12 learners' perceptions on integrating reading and writing as a key construct to understand their literacy practices involved in the composing process.

• Cross-Cultural Studies
• /
• v.53
• /
• pp.251-277
• /
• 2018

The purpose of this study was to investigate ways to improve the effect of English-medium instruction (EMI) in Korean universities by comparing EMI lectures in two Korean universities with those in a Japanese university. Some universities run all courses in English while others do so for only part of them. This study comparatively investigated how EMI courses were run by these two groups of universities. For the purpose of this study, in-depth interviews were conducted with EMI instructors and students to find out what merits and problems that such EMI programs had in EFL environment of Korea and Japan. Another important goal was to correct problems and improve the Korean programs. The result showed that the most important issue of EMI programs in Korean universities was students' low English proficiency. It also demonstrated that English for Academic Purposes (EAP) was necessary to overcome this problem. It is a key to the success of MI programs. Hopefully, this study will stimulate continuous discussions on limitations and ways to improve EMI in Korean universities in various aspects.