• Physical Therapy Korea
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• v.21 no.4
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• pp.40-48
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• 2014

Differential item functioning (DIF) based on Rasch model can be used to examine whether the items function similarly across different groups and identify items that appear to be too easy or difficult after controlling for the ability levels of the compared groups. The Oswestry low back pain disability (Oswestry) has traditionally been proved as an effective instrument measuring disability resulting from low back pain (LBP). In this study, DIF method was used to explore whether items on the Oswestry perform similarly across two different groups (participants with LBP and no LBP). A series of Rasch analyses on the 10 items of the Oswestry were performed using Winsteps$^{(R)}$ software. Forty-two participants with back pain were recruited from 3 rehabilitation hospitals in Gainesville, Florida. Another 42 participants with no LBP were recruited from several public places in the rehabilitation hospitals. Based on the DIF analysis across the two groups, several items were found to have an uniform DIF. Participants with no LBP had more difficulty on lifting and personal care items and participants with LBP had more difficulty on sleeping and social life items. For non-LBP group, a high ceiling effects (83% of participants with non-LBP) was detected, which was not be able to be effectively measured with the Oswestry items. Although 4 items of the Oswestry function differently across the two groups, all items of the Oswestry were well targeted the LBP group.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5579-5585
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• 2015

In FFT(Fast Fourier Transform) implementation, DIT(Decimation-In-Time) and DIF (Decimation-In-Frequency) methods are mostly used. Among them, various DIF structures such as Radix-2/4/8 algorithm have been developed. Compared to the DIF, the DIT structures have not been investigated even though they have a big advantage producing a sequential output. In this paper, a butterfly structure for DIT Radix-8 algorithm is proposed. The proposed structure has smaller latency time because of Radix-8 algorithm in addition to the advantage of the sequential output. In case of 4096-point FFT implementation, the proposed structure has only 4 stages which shows the smaller latency time compared to the 12 stages of Radix-2 algorithm. The proposed butterfly can be used in FFT block required the sequential output and smaller latency time.

• Journal of Information Technology and Architecture
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• v.9 no.3
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• pp.275-285
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• 2012

DIFs (Data Interchange Formats) are needed to enhance interoperability of physically distributed organizations in SBA (Simulation Based Acquisition) process. DIFs play a role as a template of DPDs (Distributed Product Descriptions) and provide capability to use information directly without data format interchange process by allowing access to DPDs, which include various information and M&S (Modeling & Simulation) resources. This characteristic is essential for interoperability in ICE (Integrated Collaborative Environment) based SBA. This paper proposes a framework for the DIF and outputs from each phase of acquisition process for configuration data related to design and manufacturing in SBA process - Conceptual Data Model, Logical Data Model, Physical Data Model and Physical DIF based on XML. Finally, we propose the DIF model architecture and demonstrate the implementation of DIF example based on it.

• Proceedings of the KIEE Conference
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• 2007.11c
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• pp.70-73
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• 2007

Many methods have been developed to overcome the PAPR(peak-to-average power ratio) problem. Selective mapping(SLM) partial transmit sequence(PTS), subblock phase weighting(SPW) and gradient descent(GD) are used widely to reduce the PAPR. In this paper, we present a effective PAPR reduction method, decrease the calculation through Radix-2 DIF IFFT procedure and GD method. and can transmit selecting data sequence that satisfy threshold value as one part of proposed method, in case satisfy fixed threshold value, or transmit selecting data sequence with the lower papr operating remained part for performance improvement.

• Coupled systems mechanics
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• v.9 no.1
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• pp.63-75
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• 2020

Transport is the central ingredient of all numerical schemes for hyperbolic partial differential equations and in particular for hydrodynamics. Transport has thus been extensively studied in many of its features and for numerous specific applications. In more than one dimension, it is most commonly plagued by a major artifact: mesh imprinting. Though mesh imprinting is generally inevitable, its anisotropy can be modulated and is thus amenable to significant reduction. In the present work we introduce a new definition of stencils by taking into account second nearest neighbors (across cell corners) and call the resulting strategy "co-mesh approach". The modified equation is used to study numerical dissipation and tune enlarged stencils in order to minimize transport anisotropy.

• Structural Engineering and Mechanics
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• v.12 no.4
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• pp.409-428
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• 2001

The characteristics of dynamic wheel loads of heavy vehicles running on bridge and rigid surface are investigated by using three-dimensional analytical model. The simulated dynamic wheel loads of vehicles are compared with the experimental results carried out by Road-Vehicles Research Institute of Netherlands Organization for Applied Scientific Research (TNO) to verify the validity of the analytical model. Also another comparison of the analytical result with the experimental one for Umeda Entrance Bridge of Hanshin Expressway in Osaka, Japan, is presented in this study. The agreement between the analytical and experimental results is satisfactory and encouraging the use of the analytical model in practice. Parametric study shows that the dynamic increment factor (DIF) of the bridge and RMS values of dynamic wheel loads are fluctuated according to vehicle speeds and vehicle types as well as roadway roughness conditions. Moreover, there exist strong dominant frequency resemblance between bounce motion of vehicle and bridge response as well as those relations between RMS values of dynamic wheel loads and dynamic increment factor (DIF) of bridges.

• International Journal of Computer Science & Network Security
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• v.22 no.5
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• pp.49-54
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• 2022

The objective of this study was to examine the function of the items on the Arabic version of the Social Networking Time Use Scale (SONTUS) using Differential Item Functioning (DIF) across groups of university students in SA (i.e., males and females at UQU). The findings of this study indicated that some of the items in the Arabic version of the SONTUS functioned differently across male and female students in SA. University faculty and administrators in Saudi Arabia as well as in the Arabic world can benefit from understanding students use of SNS.

• Korean Journal of Clinical Pharmacy
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• v.19 no.1
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• pp.1-17
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• 2009

Adverse drug reactions (ADR) caused by inappropriate prescription are responsible for major socioeconomic loss. Drug-drug interactions (DDI) has been recognized as a major part of ADRs and, therefore, healthcare professionals should prevent possible DDIs to minimize preventable ADRs. This study aimed to examine DDI information in drug information references and Korea Food & Drug Administration (KFDA) drug labeling information. Drug ingredients from the formulary of Health Insurance Review and Assessment Service in Korea (HIRA) were included for the study. DDI information source used for the study were Micromedex Drugdex and Drug Information Facts (DIF) with the DDI severity level of "moderate" or more. The DDI information in KFDA drug labeling were collected and compared. Drug ingredients were classified with KFDA Drug Classification and ATC Classification of WHO for the analysis. Among the total 1,355 drug ingredients satisfying inclusion criteria, 738 ingredients involved at least one DDI, which was described in Micromedex and/or DIF. Drug Ingredients of 176 involved DDI only described in KFDA drug labeling, but not Micromedex nor DIF. Drug ingredients of 35 which DDIs were described in Micromedex or DIF did not have DDI based on KFDA drug labeling. Micromedex and DIF retrieved 7,582 and 3,071 DDIs, respectively 57.6% and 58.5% of DDIs were also described in KFDA drug labeling. Central nervous system (CNS) drugs, cardiovascular system (CVS) drugs and the antiinfectives appeared to have higher frequency of DDIs among all drug classes. The highest number of DDIs with high severity level ("contraindicated" or "major") were the DDIs of CNS drugs. The antiinfectives are the second drug group having serious DDIs. The DDI pairs of the CNS drug and the antiinfective had the highest contraindication risk (13.6%). DDI information from Micromedex and DIF were not consistent with the result that only 465 ingredients' DDIs are common in both literature (total DDI numbers were 715 vs 488, respectively). And 1,652 DDI information are common in both references among 7,582 vs 3,071 DDIs, respectively. Only 55.2% of DDI information in the database contained in the KFDA drug labeling. Prescribers and pharmacists should pay attention to the drugs for CV system, CNS and infections because of higher risk of possible DDIs compared to other drug classes. KFDA drug labeling is not likely to be recommended as a good information source for DDI due to significant inconsistency of information. Drug information providers should be aware that DDI information from different sources are not consistent and therefore multiple references should be used.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.3
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• pp.1405-1410
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• 2016

Background: The European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Bone Metastases Module (EORTC QLQ-BM22) is a recently designed supplement to EORTC Quality of Life Questionnaire-C30 (EORTC QLQ-C30). Additional psychometric properties, especially using confirmatory factor analysis (CFA) and the Rasch model, are warranted. Materials and Methods: A total of 573 patients with bone metastases were enrolled from eight countries with a mean${\pm}$SD age of $55.8{\pm}13.7years$. Slightly more than two thirds of them were female (n=383; 66.8%). CFA was used to examine the BM22 framework; Rasch models were applied to understand misfit items and differential item functioning (DIF). Results: The fit indices were satisfactory in CFA (comparative fit index=0.972, Tucker-Lewis index=0.964, root mean square error of approximation=0.076, and standardized root mean square residual=0.045). All items fit well in the Rasch models (mean square values were between 0.5 and 1.5), and only one item (number 17) displayed DIF across gender. However, there were six DIF items across Canada and Taiwan, ten across Canada and Iran, and six across Taiwan and Iran. Conclusions: The BM22 has satisfactory psychometric properties, and could assess the QoL of patients with bone metastases specifically focusing on their symptoms. Clinicians may want to use it to capture the underlying QoL for patients with bone metastases. However, the score of item 17 should be interpreted with caution when comparing male and female patients. In addition, researchers should note that variation in DIF items may occur when conducting an international study.

• Proceedings of the Korean Association for Survey Research Conference
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• 2002.06a
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• pp.8-34
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• 2002

This paper is concerned with evaluating the fidelity of a non-cognitive test adaptation for use in multiple languages and cultures using two differential item functioning(DIF) techniques: (a) PSIBTEST, and (b) Logistic Discriminant Function Analysis(LDFA). In particular, this study focused on how DIF research can best be extended to the problem of evaluating the equivalence of tests across cultures and languages. The Sixteen Personality Factor (16PF) questionnaire was administered in English to 844 American college students and in Korean to 538 Korean college students. This study attempted to identify the best matching criterion for the translated tests by using both a multivariate matching technique and iterative purification process. The results generally showed a small number of DIF items on each scale, except for scales A and N where about half of the items showed DIF. The choice of matching variables based on a combination of internal measures appeared to have little effect and the iterative purification method was unsuccessful. Finally, the results were discussed and methodological implications were also presented.