• 품질경영학회지
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• 제20권2호
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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.

• 한국수학교육학회지시리즈A:수학교육
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• 제46권4호
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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.

• 품질경영학회지
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• 제20권1호
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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.

• 과학교육연구지
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• 제37권2호
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• pp.278-293
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• 2013

이 연구에서는 2009 개정 교육과정에 따른 고등학교 융합형 '과학' 교과에서 사용된 선다형 평가 문항의 특성을 분석하였다. 문항의 출제 경향을 분석하기 위해 융합형 교과에 특이적인 분석틀을 구안하여 분석하였으며, 문항 반응 이론을 적용하여 문항의 특성을 양적으로 분석하였다. 문항의 출제 경향 분석 결과, 문항 출처, 융합 범위, 인지 수준 측면에서 융합형 '과학' 교과의 취지를 제대로 반영하고 있지 못하는 것으로 나타났으며, 기존 교육과정의 과학 교과와 같은 분과적 교수-학습 및 평가가 이루어지고 있음을 알 수 있었다. 문항 반응 이론을 적용한 분석 결과, 대체로 문항의 난이도는 적절하며, 변별도는 높은 수준인 것으로 나타났다. 하지만 분석틀을 구성하는 3개 범주와의 연관성은 나타나지 않았다. 이와 같은 연구 결과를 토대로 융합형 '과학' 교과의 취지를 반영한 교수-학습과 평가를 위한 개선점을 논의하였다.

• 한국전문물리치료학회지
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• 제18권2호
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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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• 제15권3호
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• pp.465-481
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• 2008

문항반응이론(Item response theory: IRT)에서는 문항이 가지고 있는 특성을 기초로 피험자의 능력을 추정하고 동시에 각 문항별 문항특성곡선(Item characteristics curve: ICC)을 이용하여 문항모수를 추정하게 된다. 그러나 모수추정에 있어서 최대 우도추정의 경우는 초기값과 다른 여러 문제들이 발생할 수 있다. 본 연구에서는 추정 문제 해결방법의 대안으로 점근적 근사화 방법(Asymptotic approximation method: AAM)을 제안한다. 이는 자료의 수가 적거나 국소 변동이 있는 경우에 효과적인 추정방법이라고 할 수 있다. 이에 개발된 'Any Assess' 시스템을 모의실험을 통하여 신뢰성을 검정하였다.

• 중환자간호학회지
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• 제15권3호
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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.

• 대한가정학회지
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• 제44권4호
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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.

• 한국전문물리치료학회지
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• 제23권2호
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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.

• 한국수학교육학회지시리즈A:수학교육
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• 제61권4호
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• pp.581-595
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• 2022

본 연구의 목적은 수학 교과에서 자동문항생성을 활용하여 지식의 핵심 구조인 온톨로지모형 기반의 문항모형을 CAFA 시스템을 통해 제작하는 절차를 명세하고, 생성된 문항 사례들을 탐색하는 데 있다. 이를 위한 사례로 수학 3의 대푯값과 산포도 단원의 평가준거 성취기준을 바탕으로 개념과 계산을 포함한 내용적 특성과 적용을 포함한 과정적 특성을 바탕으로 형성평가에 적합한 문항모형을 제작하였다. 하나의 문항모형에서 생성된 문항 유형은 최선답형, 정답형, 합답형, 미완성문장형, 부정형, 진위형, 배합형 등이었으며, 매체로는 Google Chart, HTML, TTS, 그림, 비디오 등을 활용할 수 있는 것으로 나타났다. 이를 바탕으로 자동문항생성 기반의 디지털 평가 활용방안에 대한 시사점을 학생, 예비교사, 일반교사 그리고 특수교육 측면에서 논의하고, 본 연구의 한계점과 향후 연구방향을 제시하였다.