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Bi-factor MIRT True-Score Equating for Testlet-Based Tests
이규민(Gue min Lee),Won Chan Lee,Michael J Kolen,박인용(In Yong Park),Dong In Kim,Ji Seung Yang 한국교육평가학회 2015 교육평가연구 Vol.28 No.2
Lee and Lee (2014) proposed bi-factor multidimensional item response theory model (BFM) "observed-score" equating procedures. The main purposes of this study were to develop BFM "true-score" equating procedures, and to investigate applicability of the proposed procedures with actual data. Eight equating methods (including both true- and observed-score) based on dichotomous IRT (2-parameter logistic model: 2PL), polytomous IRT (graded response model: GRM), testlet response model (TRM), and BFM were compared with target equipercentile equating. Data for this study were from the Reading Comprehension test for a large-scale state assessment program, which consisted of several passages and corresponding groups of items. True- and observed-score equating methods based upon 2PL and BFM produced similar equating results. The GRM true- and observed-score equating methods provided equating results somewhat different from others, and more similar to the target equipercentile equating. Lee와 Lee(2014) 연구는 혼합형 검사에서의 bi-factor 다차원 문항반응모형을 적용한 IRT "관찰점수" 동등화 절차를 제안하였다. 이 연구는 Lee와 Lee(2014) 연구의 추수연구로 단위검사를 대상으로 bi-factor 다차원 문항반응모형을 적용한 IRT "진점수" 동등화 절차를 제안하고, 그 적용 가능성을 실제 자료를 이용하여 탐색하고자 하였다. 이를 위해 단위검사로 구성된 대규모 독해 검사 자료를 이용하여, 2모수 로지스틱 모형(2-parameter logistic model: 2PL), 등급반응모형(graded response model: GRM), 단위검사모형(testlet response model: TRM), bi-factor 모형(bi-factor model: BFM)을 적용하였으며, 관찰점수 및 진점수 동등화를 시행하여 총 8개의 동등화 방법을 적용하고, 산출된 결과를 동백분위 동등화 결과와 비교하였다. 연구 결과, 2PL과 BFM을 적용한 관찰점수 및 진점수 동등화는 유사한 결과를 산출하였으며, GRM을 적용한 관찰점수 및 진점수 동등화 방법은 다른 방법들과 다소 차이를 보이는 결과를 산출하였고, 비교 기준이 된 동백분위 동등화 결과와 보다 유사한 결과를 보였다.
이현(Lee, Hyun),김정현(Kim J.H.),이성복(Lee, Sung-Bok),엄정희(Eom, Jeong-Hee),이강오(Rhee, Kang-Oh),이태용(Lee, Tae-Yong) 한국산학기술학회 2013 한국산학기술학회논문지 Vol.14 No.8
본 연구의 목적은 연령별 난시빈도를 알아보고 굴절난시와 각막난시, 내부난시의 연령에 따른 변화와 변화 요인을 알아보고자 하였다. 2010년 7월에 만5~59세의 청주지역 거주자 1,017명을 대상으로 굴절력과 각막전면굴절력 을 자동굴절검사기로 측정하였다. 난시빈도는 전체적으로 22.7%이었고, 5~9세에 8.9%에서 20대에 36.8%로 증가하였 다. 40대에는 19.2%로 감소하였다가 50대에 28.6%로 다시 증가하였다. 굴절난시와 각막난시, 내부난시의 J<sub>45</sub>성분은 연 령군에 상관없이 거의 일정하였으나 굴절난시와 각막난시의 J<sub>0</sub>성분은 30대 이후 감소하는 경향성을 보였다. 또한 J<sub>0</sub>성 분 중에서 수직방향 굴절력은 연령에 따라 변화가 없이 일정하였지만 수평방향 굴절력은 연령에 따라 큰 변화가 있 었다. 연령에 따른 난시빈도의 변화는 수평방향 굴절력의 변화에 기인하는 것으로 판단된다. The purpose of present study was to determine the frequency of RA with age and to investigate the age-related trends and changing-factors in RA, CA and IAs. The refractive power of the eye and the power of corneal anterior surface were measured with auto-refractor among 1,017 inhabitants aged 5 to 59 years in Cheongju in July 2010. The overall frequency of RA was 22.7%, and frequency of RA increased from 8.9% in 5~9 years age group to 36.8% in 20~29 years age group. It then dipped to 19.2% in 40~49 years age group but increased again 28.6% in 50~59 years age group. J<sub>45</sub> components for RA, CA, and IAs were fairly stable in different age groups, the changes in J<sub>0</sub> components for both RA and CA appeared to be decreased after age of 30 years. In addition, the refractive power on the vertical direction was changed slightly with age, but the refractive power on the horizontal direction was changed significantly with age. It was expected that the change in the frequency of astigmatism with age was due to the change in the refractive power of horizontal meridian.
Cho, Min-Yong,Kim, Paul,Kim, Ga-Young,Lee, Ju-Yeon,Song, Keon-Hyoung,Lee, Min-Jeong,Yoon, Woojin,Yun, Hoseop,Choi, Guang J. The American Chemical Society 2017 CRYSTAL GROWTH AND DESIGN Vol.17 No.12
<P>A novel co-crystal of aripiprazole (ARI), the active substance in the atypical antipsychotic Abilify, with orcinol (ORC) as a coformer, was prepared, characterized, and compared with other ARI co-crystals with dihydroxy- and trihydroxy-benzene coformers [catechol (CAT), resorcinol (RES), and phloroglucinol (PHL)] reported previously (Nanubolu, J. B.; Ravikumar, K. <I>CrystEngComm</I> <B>2016</B>, <I>18</I>, 1024–1038). Three preparation methods were used: neat grinding (NG), liquid-assisted grinding (LAG), and solvent evaporation (SE). Based on single-crystal X-ray diffraction (SC-XRD) measurements, the crystal structure of the ARI–ORC co-crystal was determined to be monoclinic. The melting point of ARI–ORC co-crystal was found to be 184–185 °C, higher than existing ARI co-crystals with multihydroxybenzene coformers. Additionally, the ARI–ORC co-crystal showed the highest dissolution rate among those in the test group in an acetonitrile–water 10/90 cosolvent. We investigated how the co-crystallization pathway and the dissolution behavior might correlate with the coformer moiety, primarily in terms of its chemical structure and melting point. Co-crystallization between ARI and PHL via grinding (NG or LAG) required the highest activation energy, mainly due to the coformer’s higher melting point. The dissolution rate of ARI co-crystals was not obviously correlated with the coformer’s melting point or its molecular weight. However, the high dissolution rate of ARI–ORC co-crystals was possibly associated with the bond angle of D–H···A for O3–H3O···N2 in the co-crystal’s superlattice structure. The stability of ARI co-crystals was examined by aging these powders in a controlled oven at 80 °C/98% relative humidity for 1 week. We observed that all of the co-crystal powders, except for the aripiprazole–catechol (ARI–CAT) pair, underwent no noticeable degradation or physicochemical change upon treatment. In conclusion, we can consider the novel ARI–ORC co-crystal as a potential drug substance with the enhanced dissolution behavior in aqueous media and good stability under stressed conditions.</P><P>A novel co-crystal of aripiprazole (ARI), the active substance in the atypical antipsychotic Abilify, with orcinol (ORC) as a coformer, was prepared, characterized, and compared with other ARI co-crystals with dihydroxy- and trihydroxy-benzene coformers [catechol (CAT), resorcinol (RES), and phloroglucinol (PHL)] reported previously. In conclusion, we can consider the novel ARI−ORC co-crystal as a potential drug substance with the enhanced dissolution behavior in aqueous media and good stability under stressed conditions.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cgdefu/2017/cgdefu.2017.17.issue-12/acs.cgd.7b01281/production/images/medium/cg-2017-01281j_0014.gif'></P>
Cho, Changsoon,Kang, Hyunbum,Baek, Se-Woong,Kim, Taesu,Lee, Changyeon,Kim, Bumjoon J.,Lee, Jung-Yong American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.41
<P>This paper reports the distinct roles- of Au and Ag nanoparticles; (NPs) in organic light-Orating-diodes (OLEDS) depending on their sizes. Au and Ag-NPs that.are 40 arid 50 nm in size, respectively, are the most effective for enhancing the performance of green: OLEDs. The external quantum efficiencies (EQEs): of green OLEDs doped with An and Ag N.Pg, (40 and 50 rim, respectiVely) are improved by 29.5% and 36.1%, respectively, while the power. efficiencies (PE8) are enhanced by 47.9% and 37.5%, respectively. Furthermore, combining the Au and Ag NPs produces greater enhancements. The EQE and PE of the coci-oped OLEDs are improved by 63.9% and 68.8% respectively,-.through the synergistic behavior of the different NPs. Finite difference time-domain simulations confirm that the localized surfaee:plasmon resonance of the Au NPs near 580 nth improves the radiative recombination rate (k(rad)) of green-light emitters locally (<50 pm), while the Ag NPs cause relatively long, range and broadband enhancements in k(rad). The-Simulations of 'various domain sizes. Verify that the light-extraction efficiency (LEE),can, be enhanced by More than 4.2% by applying Ag NPS.. Thus, size-controlled Au and Ag NPs can synergistically enhance LEDS by improving both the internal quantum efficiency and LEE.</P>