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.

인간포배기 배아의 효과적인 유리화 동결법의 개발을 위한 연구

이상민,이주희,이상원,이승민,윤산현,임진호,박흠대,이성구,Lee, Sang-Min,Lee, Ju-Hee,Lee, Sang-Won,Lee, Seoung-Min,Yoon, San-Hyun,Lim, Jin-Ho,Park, Huem-Dai,Lee, Seong-Goo 대한생식의학회 2003 Clinical and Experimental Reproductive Medicine Vol.30 No.3

Objective: The purpose of this study was to evaluate the survival rate of vitrified blastocyst according to the freezing vessels, equilibration time in cryoprotectant and artificial dehydration method. Methods: Human blastocysts were vitrified after loading onto the plastic straw, open-pulled straw (OPS), electron microscopy grid (EM grid) for 1.5 min or 3 min. They also were directly plunged into LN2 within 30sec. For artificial shrinkage of blastocysts, 36 gauge fine needle was pushed at the cellular junction of the trophectoderm into the blstocoele cavity until it shrank without damage of inner cell mass. Results: The survival rate of vitrified blastocysts on plastic straw, OPS, EM grid as freezing vessels were 26.7, 13.0 and 60.5%, respectively. The survival rate of EM grid was significantly higher than that of plastic straw and OPS (p<0.05). For 1.5 min equilibrium, the survival rates of early blastocyst (EB), middle blastocyst (MB) and late blastocyst (LB) were 64.4, 81.0, and 20.0% respectively. For 3 min equilibrium, the survival rates of EB, MB, and LB were 69.9, 50.0 and 57.5% respectively. The survival rates of EB and MB were significantly higher than that of LB in 1.5 min equilibrium group (p<0.05), however, the significance was not observed in 3 min equilibrium groups. In cytoplasmic shrinkage before vitrification, the survival rates of EB, MB and LB were 92.9, 100 and 75.9% respectively. The survival rate of MB was significantly higher than that of LB (p<0.05). The survival rates of vitrified blastocysts by artificial dehydration and slow-frozen blastocysts were not significantly different as 88.9 and 66.7%, respectively. Conclusion: This study showed that the vitrification of human blastocysts using EM grid and artificial dehydration is an effective method. Therefore, these methods would be an useful techniques for blastocyst cryopreservation.

가압가열 및 microwave에 의한 중력분 반죽 gliadin의 항원성 변화

곽지희(Ji-Hee Kwak),김꽃봉우리(Koth-Bong-Woo-Ri Kim),이청조(Chung-Jo Lee),김민지(Min-Ji Kim),김동현(Dong-Hyun Kim),선우찬(Chan Sunwoo),정슬아(Seul-A Jung),김현지(Hyun-Jee Kim),최정수(Jung-Su Choi),김성원(Seong-Won Kim),안동현(Dong-Hyun 한국식품과학회 2012 한국식품과학회지 Vol.44 No.1

본 연구에서는 가압가열 및 microwave 처리에 의한 중력분 반죽 추출물 내의 gliadin 단백질의 항원성 변화에 대해 살펴보았다. 중력분 반죽에 가압가열과 microwave를 단독 또는 병행으로 처리하여 ci-ELISA, SDS-PAGE 및 immunoblotting을 실시하였으며, 가압가열 처리에 의해서 anti-gliadin IgG 항체와 gliadin과의 결합력이 다소 감소한 것을 확인하였다. 특히 30 min 이상 처리시 더욱 감소한 것으로 나타났으며, SDS-PAGE와 immunoblotting 결과에서도 gliadin band의 강도가 약해지고 항체와의 반응도 나타나지 않았다. Microwave 처리의 경우, 5 min 이상 처리시 일부 gliadin 단백질의 소실이 관찰되었으나, 항원성에는 큰 변화가 없었다. 또한 가압가열 및 microwave 병행 처리에 의해 항원-항체 결합력이 더욱 감소되었으며, 특히 가압가열 50 min, microwave 10 min 처리시 약 35.0%로 감소되었다. 이상의 결과를 통해 가압가열 처리에 의해 중력분 반죽 추출물 내 gliadin의 항원성이 감소되는 것을 확인하였으며, microwave와 병행 처리하는 경우, 더욱 감소하는 것을 확인하였다. The aim of this study was to determine the optimal physical treatment to reduce the antigenicity of gliadin in wheat dough. Medium wheat dough was treated with an autoclave (5, 10, 30, and 50 min at 121℃, 1 atm), a microwave (1, 5, and 10 min) or both (10, 30, and 50 min/5, 10 min). The proteins in the dough extracts were analyzed by SDS-PAGE and the binding ability of anti-gliadin IgG to gliadin was examined by ci-ELISA and immunoblotting. Results showed that the ability of anti-gliadin IgG to bind to gliadin in wheat dough treated with an autoclave alone or in combination with a microwave was decreased. Especially, it declined to ~77% after autoclaving for 30 min and 35% after both autoclaving for 50 min and microwaving for 5 min. In addition, the intensity of gliadin bands in SDS-PAGE were weakened and anti-gliadin IgG did not recognize gliadin in immunoblotting. However, microwaving alone did not affect the antigenicity of gliadin in wheat dough. These results indicate that autoclaving may affect the reduction of the antigenicity of gliadin in medium wheat dough. Moreover, autoclaving in combination with microwaving is more effective for reducing the antigenicity of wheat dough.

Improvement and Application for Environmental Conservation Value Assessment Map(ECVAM) of Nationwide Land in Korea

Lee, Moung-Jin,Jeon, Seong-Woo,Jo, Min-Jeong,Song, Won-Kyong,Kang, Byung-Jin The Korean Society of Remote Sensing 2007 大韓遠隔探査學會誌 Vol.23 No.5

This study is aiming at improving the Environmental Conservation Value Assessment Map(ECVAM) of National Land in Korea. The ECVAM items are composed of legal and environmental/ecological assessments. A popular method applied to ECVAM is an overlay environmental/ecological assessment items. The purpose of this study is to offer complementary items of the ECVAM by examining assessment items. In this study we assessed the ECVAM by five methods. Method 1 is Grade 1 areas of each administrative district; Method 2 is comparing overlapped areas of each assessment items Grade 1, 2 and permission of each assessment items duplication; Method 3 is Grade 1, 2 areas by only singular assessment items; Method 4 is Grade 1 areas only of Method 2; and Method 5 is Grade 2 areas only of Method 2. Method 1 showed Seoul and other metropolitan cities revealed a large proportion of Grade I regions by the legal assessment items. Gang won-Do, showed a large proportion of Grade I regions by the environmental/ecological assessment item. Method 2 showed 93.4% of diameter Grade II(standard for stability); forest diameter item accounted for 99.9% by Method 3, Method 4 showed 95.7% of forest diameter, and forest density accounted for 66.4% by Method 5. This study contributes to reduce the complexity in the process of manufacturing ECVAM of National Land, and to raise the flexibility in the process of managing and updating this map.

Optimization of Ascorbic Acid Extraction from Rugosa Rose (Rosa rugosa Thunb.) Fruit Using Response Surface Methodology and Validation of the Analytical Method

( Min Um ),( Ji-woo Kim ),( Jae-won Lee ) 한국목재공학회 2020 목재공학 Vol.48 No.3

In this study, ultrasound-assisted extraction was performed to extract ascorbic acid from rugosa rose (Rosa rugosa Thunb.) fruit. The optimal conditions were investigated by response surface methodology, using two variable including reaction time (16-44 min) and temperature (16-44°C). The ascorbic acid extraction was sensitive to the reaction time rather than the reaction temperature, and the optimal conditions for ascorbic acid extraction were 25°C and 30 min. Ascorbic acid and gallic acid in the rugosa rose fruit extract were completely separated by HPLC, with a resolution factor of over 1.5 between the two. The correlation coefficient of the ascorbic acid was 0.999 in a linearity test for 50-150 μg/mL concentration of extract. The limit of detection and limit of quantification values were 0.16 μg/mL and 29.89 μg/mL, respectively. The relative standard deviations (RSD) for repeatability and reproducibility were determined, and each RSD showed good precision at less than 5% (N=6).

Active Balancing of Li-Ion Battery Cells Using Transformer as Energy Carrier

Lee, Kyung-Min,Lee, Sang-Won,Choi, Yoon-Geol,Kang, Bongkoo Institute of Electrical and Electronics Engineers 2017 IEEE transactions on industrial electronics Vol.64 No.2

<P>A circuit for balancing Li-ion battery cells is proposed. This circuit requires one small transformer and N + 3 bilateral switches to equalize the charging states of N serially connected battery cells. The transformer works as an energy carrier, and the switches select two unbalanced cells that require an energy transfer from one to the other cell. The circuit was tested for a 12-cell Li-ion battery under static, cyclic, and dynamic charging/discharging conditions. Under static condition, the power-transfer efficiency was measured as 80.4% at a balancing power of 0.78W; two 4400-mA . h battery cells at a state of charge (SOC) = 70 and 80% were equalized after 78 min. The results of cyclic and dynamic charging/discharging conditions show that the circuit is appropriate for balancing the Li-ion battery cells for vehicles and energy storage systems.</P>

Characterizations of Modified Silica Nanoparticles(I)

Min, Seong-Kee,Park, Chan-Young,Lee, Won-Ki,Seul, Soo-Duk Materials Research Society of Korea 2012 한국재료학회지 Vol.22 No.6

(3-mercaptopropyl)trimethoxysilane (MPTMS) was used as a silylation agent, and modified silica nanoparticles were prepared by solution polymerization. 2.0 g of silica nanoparticles, 150 ml of toluene, and 20 ml of MPTMS were put into a 300 ml flask, and these mixtures were dispersed with ultrasonic vibration for 60 min. 0.2 g of hydroquinone as an inhibitor and 1 to 2 drops of 2,6-dimethylpyridine as a catalyst were added into the mixture. The mixture was then stirred with a magnetic stirrer for 8 hrs. at room temperature. After the reaction, the mixture was centrifuged for 1 hr. at 6000rpm. After precipitation, 150 ml of ethanol was added, and ultrasonic vibration was applied for 30 min. After the ultrasonic vibration, centrifugation was carried out again for 1 hr. at 6000rpm. Organo-modification of silica nanoparticles with a ${\gamma}$-methacryloxypropyl functional group was successfully achieved by solution polymerization in the ethanol solution. The characteristics of the ${\gamma}$-mercaptopropyl modified silica nanoparticles (MPSN) were examined using X-ray photoelectron spectroscopy (XPS, THERMO VG SCIENTIFIC, MultiLab 2000), a laser scattering system (LSS, TOPCON Co., GLS-1000), Fourier transform infrared spectroscopy (FTIR, JASCO INTERNATIONL CO., FT/IR-4200), scanning electron microscopy (SEM, HITACHI, S-2400), an elemental analysis (EA, Elementar, Vario macro/micro) and a thermogravimetric analysis (TGA, Perkin Elmer, TGA 7, Pyris 1). From the analysis results, the content of the methacryloxypropyl group was 0.98 mmol/g and the conversion rate of acrylamide monomer was 93%. SEM analysis results showed that the organo-modification of ultra-fine particles effectively prevented their agglomeration and improved their dispensability.

열처리에 따른 CVD Cu 박막의 미세구조 및 전기 비저항의 변화

이원준(Won-Jun Lee),민재식(Jae-Sik Min),라사균(Sa-Kyun Rha),이영종(Young-Jong Lee),김우식(Woo-Sik Kim),김동원(Dong-Won Kim),박종욱(Chong-Ook Park) 한국진공학회(ASCT) 1995 Applied Science and Convergence Technology Vol.4 No.2

열처리에 따른 Cu 박막의 미세구조 및 전기 비저항의 변화를 조사하였다. Cu(hfac)(TMVS)를 원료로 하는 저압화학증착법에 의해 증착온도를 160℃에서 330℃까지 변화시키면서 TiN 기판 위에 Cu 박막을 제조하였고 450℃에서 30분간 열처리하였다. 증착온도에 따라 표면이 평평한 Cu 박막을 형성하는 표면 반응제한지역과 표면이 거친 Cu 박막을 형성하는 물질전달제한지역이 관찰되었다. 열처리 후 Cu 박막은 전체적으로 표면이 평탄해졌고 결정립의 크기는 모든 증착온도에서 증가하였는데 그 편차 역시 증가하여 EM 저항성 측면에서는 큰 효과를 보이지 못할 것으로 판단된다. 비저항은 증착온도 200℃에서 급격히 증가하였고 열처리 후에는 모든 증착온도에서 비저항이 감소하였는데 표면반응제한지역에서는 결정립 성장에 의한 약간의 비저항 감소를 보였으나 물질전달제한지역에서는 응집에 의해 Cu 결정립간의 전기적 연결 상태가 향상되어 급격한 비저항 감소를 보였다. The effects of the thermal annealing on the microstructure and the electrical resistivity of the copper films were studied. Copper film was prepared on TiN substrate by the low pressure chemical vapor deposition (LPCVD) using Cu(hfac)(TMVS) as the precursor at the deposition temperature between 160 and 330℃, and then annealed at 450℃ for 30 min. There were two distinct temperature regions, one is the surface reaction limited region, producing smooth surfaced copper film, and the other is the mass transport limited region which produces rough surfaced film. After annealing, the surfaces of the copper films had tendency to become smooth, and the grain size enlarged in all deposition temperature regions. However, the deviation of the grain size was increased too much to improve the EM resistance. The electrical resistivity showed a rapid increase at the deposition temperature of 200℃. After annealing, the resistivity of the copper film deposited in the surface reaction limited region decreased slightly by the grain growth, but ones deposited in the mass transport limited region decreased drastically by coalescence of the grains, causing the improvements of the electrical connections among copper grains.

The Deduction on Optimal Solution of Transport Cost by Clusters Divided Model in the Delivery System of Convenience Store

이원동(Won-dong Lee),김영민(Young-min Kim) 한국국제상학회 2016 國際商學 Vol.31 No.3

Purpose : The purpose of this study is to derive initial solutions and optimal solutions of total transport costs for each cluster divided model, and to execute the comparative analysis of the total transport costs minimal for the delivery system of convenience store. Research design, data, methodology : The zones were divided by random sampling to target a number of ships in Gangnam and Gangbuk sphere of G Convenience Store at room temperature products. After dividing to the entire cluster, two clusters and three clusters, the initial solutions were calculated by VAM program, and the optimal solutions were derived by taking advantage of the Excel Solver program each cluster. Results : In the minimum total transport costs each cluster, the entire cluster model was 736,000 Won, two clusters divided model was 770,000 Won, and three clusters derived model 696,000 was Won. Three clusters divided model got the minimum transport costs, and was shown as the most highly optimized model. Conclusions : The total transport costs can be minimized by applying an optimal solution of the cluster divided model in the delivery system of convenience stores. And it is possible to bring the efficiency of delivery vehicles and the reduction of the traffic volume, road congestion mitigation and air pollution. 본 연구에서는 편의점의 합리적인 상품 배송을 위하여 각 클러스터별로 총 운송비에 대한 수배송 초기해와 최적해를 도출하고, 어느 분할모형이 최소의 총 운송비를 가져오는지에 대해 비교분석을 하고자 한다. G편의점의 상온제품의 강남 및 강북권역의 수배송을 대상으로 무작위 샘플링을 통하여 권역을 분할하였다. 전체 클러스터, 2개 클러스터 및 3개 클러스터로 분할하여 휴리스틱으로 개발된 수배송 최적해 도출 프로그램인 VAM으로 클러스터별 초기해를 산출하고 엑셀 해찾기 프로그램을 활용하여 최적해를 도출하였다. 클러스터별 최소 총 운송비를 보면 전체 클러스터 736,000원, 2개 분할 클러스터 770,000원, 3개 분할 클러스터 696,000원으로 도출되었다. 3개 권역 분할모형이 최소 운송비를 가져오며, 2개 클러스터 분할모형의 운송비가 가장 높게 나타나 3개 권역으로 분할하여 수배송을 실시하는 경우가 최적화 모형인 것으로 확인되었다. 권역분할모형에 의한 편의점 상품 수배송의 최적해를 도출하여 총 운송비를 최소화할 수있으며, 배송차량을 효율적으로 운영할 수 있다. 또한 교통량 감소 및 도로혼잡 완화, 대기오염 감소효과도 가져올 수 있다.

AISI1045 기계구조용 탄소강의 질화 가스분위기에 따른 화합물층의 형성 및 조직변화

이원범 ( Won-beom Lee ),유광춘 ( Kwang-chun Yu ),김영민 ( Young-min Kim ),위재용 ( Jae-lyoung Wi ) 대한금속재료학회(구 대한금속학회) 2016 대한금속·재료학회지 Vol.54 No.7

Compound layers developed at 520 ℃ during gaseous nitriding of AISI 1045 steels were investigated. The nitriding potential (Kn) of a gas atmosphere of dissociating ammonia gas was checked by observation of the partial pressure of hydrogen gas. The microstructural evolution of the compound layer was studied by using optical microscopy and scanning electron microscopy. It was observed that the surface hardness was about 600 Hv after the nitriding treatment and the case depth was about 0.5mm after a nitriding treatment of 1440 min. The compound layer was composed of  ′(Fe4N) and ε(Fe2-3N). The thickness of the compound layer was simultaneously increased to 16 μm during the nitriding treatment of 1440 min. The kinetics of the compound layer growth were discussed with a modified Lehrer diagram of AISI 1045 steels, which was obtained from the thermodynamic calculation. †(Received January 15, 2016; Accepted March 2, 2016)