Yong-Won Lee

Sodium (Na) metal anodes with stable electrochemical cycling have attracted widespread attention because of their highest specific capacity and lowest potential among anode materials for Na batteries. The main challenges associated with Na metal anodes are dendritic formation and the low density of deposited Na during electrochemical plating. Here, we demonstrate a fluoroethylene carbonate (FEC)-based electrolyte with 1 M sodium bis(fluorosulfonyl)imide (NaFSI) salt for the stable and dense depo

A multitask speaking measure consisting of both integrated and independent tasks is expected to be an important component of a new version of the TOEFL test. This study considered two critical issues concerning score dependability of the new speaking measure: How much would the score dependability be impacted by (1) combining scores on different task types into a composite score and (2) rating each task only once? To answer these questions, generalizability theory (G-theory) procedures were used

Diagnostic language assessment (DLA) is gaining a lot of attention from language teachers, testers, and applied linguists. With a recent surge of interest in DLA, there seems to be an urgent need to assess where the field of DLA stands at the moment and develop a general sense of where it should be moving in the future. The current article, as the first article in this special issue, aims to provide a general theoretical background for discussion of DLA and address some fundamental issues surrou

The purpose of the study reported in this article is to empirically examine passage-related local item dependence (LID) by using an IRT (item response theory)- based LID index called Q 3 in an EFL reading comprehension test, with a special focus on item types as a potentially competing source of LID with passages. In this article, definitions and causes of LID and major LID detection methods including Q 3 statistics are reviewed along with the two potential sources of LID in EFL reading assessme

Abstract A computational tool was applied based on a two-dimensional linear method to predict the hydrodynamic loads for damaged ships. Experimental tests on a ship model have also been carried out to predict the hydrodynamic loads in various design conditions. The results of the theoretical method and experimental tests are compared to validate the theoretical method. The extreme wave-induced loads have been calculated by short-term prediction. For the loads in intact condition, the prediction

Possible integrated and independent tasks were pilot tested for the writing section of a new generation of TOEFL® (Test of English as a Foreign Language™) examination. This study examines the impact of various rating designs as well as the impact of the number of tasks and raters on the reliability of writing scores based on integrated and independent tasks from the perspective of generalizability theory (G-theory). Both univariate and multivariate G-theory analyses were conducted. It was found

The aim of this study was to investigate the hydroelastic responses on a large container ship and to provide reliable experimental data of the global loads acting on the ship. In this study, Fluid Structure Interaction (FSI) models are used to investigate nonlinear wave actions and wave-induced global loads acting on a 10,000 TEU-class container ship. The results from the computational analyses have been correlated with those from model tests. Comparisons of numerical results with experimental r

Possible integrated and independent tasks were pilot tested for the writing section of a new generation of the TOEFL® (Test of English as a Foreign Language™). This study examines the impact of various rating designs and of the number of tasks and raters on the reliability of writing scores based on integrated and independent tasks from the perspective of generalizability theory (G-theory). Both univariate and multivariate G-theory analyses were conducted. It was found that (a) in terms of maxim

This study has investigated the comparability of computer-based testing writing prompts in the Test of English as a Foreign LanguageTM (TOEFL) for examinees of different native language backgrounds. A total of 81 writing prompts introduced from July 1998 through August 2000 were examined using a 3-step logistic regression procedure for ordinal items. An English language ability (ELA) variable was created by summing the standardized TOEFL Reading, Listening, and Structure scale scores. This ELA v