• Journal of Korean Society for Quality Management
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• v.20 no.2
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• pp.33-43
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• 1992

Items are assumed to fail by degradation. An appropriate stochastic model of such item is a cumulative process in which an item can fail only when the total amount of wear exceeds a prespecified failure level. This paper presents replacement policy in which an item is replaced at a certain level of wear before failure or at failure, whichever occurs first. Yet, when measuring the item wear level is very expensive, destructive or time-consuming, it may be economical to use substitutive characteristics that are correlated with the item wear level and relatively inexpensive to measure. The item's wear level could usually be estimated by monitoring such substitutive characteristics only except for a breakdown, which may be observed immediately at its occurrence. The purpose of this paper is to find an optimal periodic replacement policy based on such substitutive characteristics that balance the cost of replacement with the cost of failure and result in a minimum total long-run average cost per unit time. The optimal level of substitutive characteristics to replace the item is obtained. Numerical example illustrate how the model can be used to determine the optimal replacement policy.

• The Mathematical Education
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• v.46 no.4
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• pp.407-421
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• 2007

The purpose of this study is to identify the item characteristics that are supposed to affect item difficulty and to estimate the regression equations for predicting item difficulty of mathematics in the College Scholastic Ability Test(CSAT). We selected six variables related to item characteristics based on learning theories: contents, cognitive domain, novelty, item type, number of concepts, and the amount of computation. With data of the CSAT mathematics test administered in 2004-2006, item difficulty was regressed on the six variables, the location of an item, and the item writer's judgment on difficulty. The novelty of an item was found to be a statistically insignificant variable in explaining item difficulty. Four regression equations with different sets of independent variables could explain $70%{\sim}80%$ of the item difficulty variance and were validated as predicting item difficulty of the mock CSAT in 2006.

• Journal of Korean Society for Quality Management
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• v.20 no.1
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• pp.59-67
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• 1992

This paper deals with preventive replacements models for the item whose failures are dependent on their wear level. When measuring the item wear level is very costly, it may be economical to use substitutive characteristics that are correlated with the item wear level and relatively inexpensive to measure. In this paper, replacement policies based on such substitutive characteristics are proposed. The optimal level of substitutive characteristic to replace the item, which minimizes total cost, is obtained. Some numerical examples are also given.

• Journal of Science Education
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• v.37 no.2
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• pp.278-293
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• 2013

The purpose of this study was to analyze the characteristics of multiple-choice test items used in assessment of high school integrated science according to 2009 revised curriculum. For the analysis of the tendency of item setting, we devised an analytic framework specific to integrated science, and analyzed the characteristics of items by applying the devised framework and item response theory. The results of the tendency of item setting revealed that most of items run counter to the intent of integrated science in terms of item resource, integration extent, and cognitive level, which means teachers are stick to separative method in teaching-learning and assessment of integrated science. The results of the analysis applying item response theory showed that item difficulty was appropriate and item discrimination was considerably high. However, there was no relevance between the tendency of item setting and qualitative characteristics of the items. We also discussed some agendas to improve the teaching-learning and assessment of integrated science based on the results of this study.

• Physical Therapy Korea
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• v.18 no.2
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• pp.35-42
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• 2011

Three hundred and fourteen low back pain patients completed the Korean version of the Oswestry Disability Questionnaire (KODQ) and the Rasch analysis was then applied to identify the inappropriate items and to determine ODQ item difficulties according to a subject's characteristics. For women and youths, the 'sex life' item showed misfit statistics, whereas for older subjects it was the 'pain intensity' and 'standing' items. Also, in the acute low back group the 'pain intensity', 'standing' and 'sex life' items showed misfit statistics. For all subjects, the most difficult item was 'pain intensity', whereas the easiest item was 'walking'. But for the older and acute groups 'lifting' was the most difficult item and for those who have a visual analogue scale score of 3 or less 'sitting' was the most difficult item. These results show that differential item functioning is present in several items according to sex, age, acute and chronic pain, and VAS score. This study may be useful for adjusting the KODQ item difficulties for low back pain patients with different characteristics.

• Communications for Statistical Applications and Methods
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• v.15 no.3
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• pp.465-481
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• 2008

Item response theory(IRT) estimates latent ability of a subject based on the property of item and item parameters using item characteristics curve(ICC) of each item case. The initial value and another problems occurs when we try to estimate item parameters of IRT(e.g. the maximum likelihood estimate). Thus, we propose the asymptotic approximation method(AAM) to solve the above mentioned problems. We notice that the proposed method can be thought as an alternative to estimate item parameters when we have small size of data or need to estimate items with local fluctuations. We developed 'Any Assess' and tested reliability of the system result by simulating a practical use possibility.

• Journal of Korean Critical Care Nursing
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• v.15 no.3
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• pp.37-50
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• 2022

Purpose : This study aimed to examine the item characteristics of the Korean version of the intensive care experience questionnaire (K-ICEQ) using the Rasch analysis model of the item response theory. Methods : In this methodological study, the validity of the scale was examined, and a secondary analysis was conducted using cohort data of patients who were discharged from the intensive care units (ICU). Data from 891 patients who responded to the K-ICEQ upon ICU discharge were analyzed. The WINSTEP program was used to analyze item characteristics, including item difficulty, fit indices, appropriateness scale, and separation reliability. Results : The difficulty level of all 26 items of the K-ICEQ was appropriate, and the fit indices of the 25 items, except for item 18, were good. The 5-point scale of the K-ICEQ was not appropriate in the three subscales. The item separation reliability was good in all subscales, but did not meet the criteria in terms of respondents. Conclusion : The results of examining the item characteristics of the K-ICEQ revealed a good degree of difficulty, fitness, and item separation reliability. To increase the validity of the K-ICEQ, we suggest the rearrangement of the overall item order, modification of the item description of the "recall of experience" subscale, and reduction of the scale response level.

• Journal of the Korean Home Economics Association
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• v.44 no.4 s.218
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• pp.175-190
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• 2006

The purpose of this research is to investigate consumers' experience of using Internet used-item markets in order to determine their motives in such activity. In terms of the Internet used-item market, (1) it contributes to a sound culture of consumption by recycling, (2) as a C2C market, it retains characteristics fundamentally different from the existing one-way type of market, (3) and it offers different characteristics from existing offline-based flea markets. Two significant themes emerged from the study results. First, users of Internet used-item markets passed through various stages such as novice, addict, and expert and learned the techniques for utilizing the used-item market. Second, for fast transactions with generalized Internet banking and the increasing trend for price bargaining emotional exchange among members is being transformed into the pursuit of transactional efficiency.

• Physical Therapy Korea
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• v.23 no.2
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• pp.35-43
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• 2016

Background: The Functional Gait Assessment (FGA) was developed to measure of gait-related activities. The FGA was translated in Korean but only a few psychometric characteristics had been studied. Objects: The purpose of this study was to evaluate the validity and reliability of the Korean version of FGA scale using Rasch analysis. Methods: The study included 120 patients with stroke (age range=30~83 years; mean${\pm}$standard deviation=$58.3{\pm}11.1$). The FGA and Berg Balance Scale were performed, and were analysed for dimensionality of the scale, item difficulty, scale reliability and separation, and item-person map using Rasch analysis. Results: The 4 rating scale categories of FGA were satisfied with optimal rating scale criteria. The most items of the FGA showed sound item psychometric properties except 2 items ('gait with the horizontal head turns', and 'gait with narrow base of support'), and the 2 misfit items were excluded for all further analyses. The 8 items were arranged in order of difficulty. The most difficult item was 'gait with eyes closed', the middle difficult item was 'gait level surface', and the easiest item was 'gait with vertical head turns.' A person separation reliability was .93 and the person separation index was 3.57. Conclusion: This study suggests that the 8-item Korean FGA are valid measure of assess the gait-related balance performance, and to set the goal of rehabilitation plan in patient with stroke.

• The Mathematical Education
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• v.61 no.4
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• pp.581-595
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• 2022

The purpose of this study is to specify the procedure for making item models based on ontology models using automatic item generation in the mathematics subject through the CAFA system, and to explore the generated item instances. As an illustration for this, an item model was designed as a part of formative assessment based on the content characteristics, including concepts and calculations, and process characteristics, including application, using the representative values and the measures of dispersion in Mathematics of the 9th grade based on the evaluation criteria achievement standards. The item types generated in one item model were a best answer type, a correct answer type, a combined-response type, an incomplete statement type, a negative type, a true-false type, and a matching type. It was found that HTML, Google Charts, TTS, figures, videos and so on can be used as media. The implications of the use of digital evaluation based on automatic item generation were suggested in the aspects of students, pre-service teachers, general teachers, and special education, and the limitations of this study and future research directions were presented.