• Communications for Statistical Applications and Methods
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• v.23 no.6
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• pp.531-541
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• 2016

Cerebral atrophy affects the brain and is a common feature of patients with mild cognitive impairment or Alzheimer's diseases. It is evaluated by the radiologist or reader based on patient's history, age and the space between the brain and the skull as indicated by magnetic resonance (MR) images. A total of 70 patients were scanned in the supine and prone positions before three radiologist assessed their atrophy level. This study examined the radiologist's assessment of the cerebral atrophy level using a graded response model of item response theory (IRT). A graded response model (GRM) is fitted to our data and then item-fit and person-fit statistics are evaluated to assess the fitted model. Our analysis found that the cerebral atrophy level is better discriminated by readers in the prone position because all item slopes were greater than 2 at this position, versus the supine position where all the slope parameters were less than 1. However, the thresholds are very similar for the first reader and are quite different for the second and third readers because the scanning position affects readers differently as the category threshold estimates vary considerably between the readers..

• Journal of Families and Better Life
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• v.28 no.6
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• pp.207-220
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• 2010

This study is intended to create a tool which can identify the concept of consumption life level and to develop a standardized scale to measure consumption life level. Based on it, the concept and perspective of consumption life level was formed and then the scale for measuring it was developed. To develop the scale, the scale was firstly formed by extracting questions through a literature survey, and verifying validity through experts' opinions. Then the final scale was developed by conducting a questionnaire survey for consumers. A preliminary 27-item scale was developed through a literature review. 1000 consumers responded to an online survey using the preliminary scale. This research was made with the intention of not only supplying academic data on the consumer's consumption life level but also understanding the consumer's basic behavior patterns. Then a series of tests: test-retest, item-to-total correlation, and Cronbach's reliability coefficient and factor analysis were conducted using the survey data and the final 20-item scale was constructed in the end. The consumer's consumption life level scale consisted of 4 factors.

• Physical Therapy Korea
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• v.30 no.1
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• pp.32-40
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• 2023

Background: Equating is a statistical procedure used to create a common measurement scale across two instruments. Item-level information should be taken into consideration so that scores can communicate interchangeably across the instruments. Objects: To investigate a common measurement scale across two health-related quality of life questionnaires (HRQOL) applied to various cancer survivors who underwent palliative care in healthcare institutions. Methods: A total of 139 cancer survivors who underwent palliative care were recruited from two rehabilitation hospitals and an oriental medicine hospital. Participants consisted of various cancer survivors who presented to the sites for palliative care. They were asked to fill out Korean versions of the World Health Organization Quality of Life (WHOQOL-BREF) and EuroQOL-5 dimension (EQ-5D) questionnaires following the palliative care. For the item level comparison, the Rasch rating scale model was used to investigate how participants regarded individual test items of two instruments in relation to item difficulty calibrations. Results: All items except the three items fit the Rasch model. One item (anxiety/depression) of the EQ-5D and two items (dependence on medical aids and negative feelings) of the WHOQOL-BREF are misfit. The WHOQOL-BREF targets the survivors well, while the EQ-5D is able to target the survivors with lower HRQOL levels with some ceiling effects. By inspecting the item difficulty calibrations of the two instruments, five items of the WHOQOL-BREF are selected as common items in relation to the EQ-5D. These five items are considered compatible with each other. Differential item functioning (DIF) analysis reveals that the healthcare item of the WHOQOL-BREF vs the self-care item of the EQ-5D exhibits significant DIF. Conclusion: Findings suggest that one paired item should be taken into consideration when equating the WHOQOL-BREF and the EQ-5D applied to cancer survivors who underwent palliative care.

• Journal of the Korean Home Economics Association
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• v.40 no.2
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• pp.67-86
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• 2002

The purpose of this research is to offer a method to derive the body shapes and pose factors with resets from analyzing factors by using the measurement values of human body. 297 male subjects in their twenties participated in this study. 54 anthropometric and 35 photographic measurements were taken from each subject. Data is the several typical items selected among items and you have to make an index value by using these typical items and convert it. The index has high correlation with each item, is easy to be measured and is to be used after selecting an important item in designing prototype. With results of analyzing reliability level by each item, correlation and items that factor loading is low, the item that the correlation is high is to be removed within the range that maintains the reliability level. Five factors of the front part and seven factors of the profile came to be derived from this kind of process.

• Journal of The Korea Institute of Healthcare Architecture
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• v.17 no.4
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• pp.25-37
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• 2011

As International considerations about the Barrier-Free environment increase, Korean Barrier-Free Environment Certification System has operated since 2008 in Korea. The purpose of this study is to find way to improve evaluation items, so this study analyzed the result of examination certified facilities and investigated the importance of the evaluation item for conducted a questionair survey with the BF experts. As a result, a lower scored and high important item should assign a higher score or lower the difficulty level, so induces applicants to be certified. Second, a higher scored and lower important item should assign a lower score or increase the difficulty of evaluating. The results suggested are expected the use in the improvement direction of BF certification evaluation items.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1994.04a
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• pp.427-431
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• 1994

The objective of this paper is to provide an inventory control policy for the system that carries a single item with a multiple demand classes, when the demand is Poisson distributed random variable. The inventory control process includes the process of determining the reorder point, and the process of inventory control during the lead time. The goal of the optimization process is to achieve the service level of each demand class as well as the system-wide total service level at a preset desired service level while sustaining a minimum average inventory.

• Journal of Korean Institute of Industrial Engineers
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• v.27 no.3
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• pp.226-232
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• 2001

This paper presents an efficient method for the problem of determining the spare inventory level of a multi-echelon repairable-item inventory system. We consider the system with two levels of inventory, two levels of service and with a general service time distribution. We propose an algorithm that determines the spare inventory level to satisfy the minimum fill rate with the minimum cost. Experimental results show that the algorithm is accurate and efficient.

• Journal of The Korean Association For Science Education
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• v.15 no.3
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• pp.263-274
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• 1995

The purpose of this study was to find out effect of problem solving by mental demand of items and chunking level of problem solver on the item. The principal findings of study were as follows ; 1) According to increase of mental demand of items. students' achievement score appeared to decrease and the more mental demand an item needed. the higher or at least the same hierarchical item was. These results showed that mental demand of item was main factor which decided difficulties of problem solving. 2) Though items have the same mental demand. students' achievement score were different between balance beam task and 2nd law task (achievement score of balance beam task < achievement score of 2nd law task). 3) Achievement score of LM group who used chunked knowledge to solve balance beam task were higher than non LM group who used non chunked knowledge. 4) The level of chunked knowledge was different between two tasks when non LM group solved items of two tasks. On the other hand, LM group used the same level of chunked knowledge to solve items of two tasks. 5) Achievement score of non LM group was the same between items of two tasks after treatment due to chunking effect by treatment. But achievement score of LM group didn't change before and after treatment. The chunking effect by treatment had an effect on non LM group, but it was not on LM group.

• Journal of Korean Institute of Industrial Engineers
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• v.1 no.2
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• pp.27-38
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• 1975

This paper explores a quantitative decision-making system for planning production, inventories and work-force in a multi-item production system. The Multi-item Parametric Decision Rule (MPDR) model, which assumes the existence of two types of linear feed-back rules, one for work-force level and one for production rates, is basically an extension of the existing method of Parametric Production Planning (PPP) proposed by C.H. Jones. The MPDR model, however, explicitly considers the effect of manufacturing progress and other factors such as employee turn-over, difference in work-days between month etc., and it also provides decision rules for production rates of individual items. First, the cost relations of the production system are estimated in terms of mathematical functions, and then decision rules for work-force level and production rates of individual items are establised based upon the estimated objective cost function. Finally, a direct search technique is used to find a set of parameters which minimizes the total cost of the objective function over a specified planning horizon, given estimates of future demands and initial values of inventories and work-force level. As a case problem, a hypothetical decision rule is developed for a particular firm (truck assembly factory).

• Journal of the Korean Data and Information Science Society
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• v.22 no.3
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• pp.487-494
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• 2011

The purpose of this study was to investigate self-esteem item goodness-of-fit in sports talented children with socio-psychological aspect, which may be a basis of developing global sports leaders. Fifty children who were selected by 2010 sports talent identification program at Korea National Sport University participated in this study. All participants were asked to answer the questionnaire using Rogenberg (1965) self-esteem scale. Total 8 questions were used with 4 point Likert scale and high point stands for higher self-esteem status. Reliability of Cronbach's ${\alpha}$ was.785 in this study. Frequency analysis, descriptive statistics, and reliability analysis were conducted with SPSS 18.0. WINSTEPS 3.70 (Linacre, 2010) was used for calculating item goodness-of-fit and subject reliability, scale propriety, item goodness-of-fit and item level of difficulty, and level of difficulty were calculated. Statistical analysis showed results as follows. First, it was reported to be suitable for subject reliability in self-esteem as 1.01~1.03 and item reliability as 1.01~1.01. Second, 4 scale was suitable for scale propriety resulting from stage index judgment. Third, 2,7,8 and 3 question showed problems in item goodness-of-fit and item level of difficulty. Finally, scale propriety was reported to be inappropriate for considering sports talented children's ability distribution and scale level of difficulty.