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SPRT형 CAT에서 검사의 신뢰도가 판정의 정확성과 효율성 미정판정에 미치는 영향
조현준,김영환,정희태 한국교육정보미디어학회 2003 교육정보미디어연구 Vol.9 No.1
본 연구에서는 IRT 기반의 AMT와 달리 문항의 모수치를 요구하지 않는 SPRT형 CAT에서 검사의 신뢰도가 판정의 정확성과 효율성 및 미정판정에 미치는 영향에 대해서 알아보았다. 특히, 지금까지의 SPRT형 CAT의 연구가 비교적 높은 검사 신뢰도에서 이루어져 왔던 것에 주목하여 학교현장에서 발생할 수 있는 다양한 검사 신뢰도 수준을 반영하여 검사 신뢰도와 판정과의 상관관계를 살펴보는데 주안점을 두었다. 연구의 목적을 달성하기 위하여 부산 C중학교 3학년 학생 340명을 대상으로 실시한 사회가 평가결과 데이터를 사용하였으며, 전체 문항에 대한 검사 신뢰도를 분석한 다음, 본 연구에서 설정한 검사 신뢰도가 구간에 해당하는 문항집단을 재구성하여 SPRT형 CAT 평가결과를 시뮬레이션 하였다. 연구결과 검사의 신뢰도는 판정의 정확성에는 영향을 주지 않지만, 판정의 효율성과 미정판정에는 영향을 미치는 것으로 나타났다. 또한, 미정판정은 파정의 정확성에 부정적인 영향을 미치며, 검사 신뢰도가 낮아질수록 그리고 결정오류를 의미하는 α, β가 작아질수록 그 영향은 커지는 것으로 분석되었다. 교육현장에서 검사의 신뢰도 수준을 SPRT형 CAT의 일반적인 기준인 Cronbach α .90 이상으로 유지한다는 것은 상당히 어려운 작업으로, 적정 검사 신뢰도(본 연구에서는 Cronbach α. 75 이상)만 지켜진다면 SPRT형 CAT에서 판정의 정확성에는 문제가 없다는 본 연구의 결과는 앞으로의 SPRT형 CAT 활용에 긍정적인 측면으로 작용할 수 있을 것이다. 결론적으로, 최소 20문항 이상에서 SPRT형 CAT가 시행되고 미정판정의 경우에는 전통적인 시험방식에 의한 점수를 기준으로 판정을 한다면, SPRT형 CAT는 다른 CAT와 비교하여 현장 적용성을 고려한 가장 현실적인 모델이 될 수 있을 것이다. The purpose of this study wds to examine and verify the effect of refiab5ty coefficient on the correctness and efficiency of decision and undecidedness irr CAT with SPRT Model. For this purpose, the four specific questions are identified such as: 1. In CAT with SPRT model, what influence will be shown in the correctness of decision on the diffexmt reliability &dent of items? 2. In CAT with SPW mxkl, what influence will be shown in the efficiency of declsion on the difEerent reliability coefficient of items? 3. In CAT with SPRT model, what influence will be shcwn in the undaiddiess on the different. reliability coefficient of items? 4. In CAT with SPRT imdel, what influence of mki&ess will be shown in the correctness? The subject of this shdy is the group of 340 students of C. middle Schotl in Pusan. The instrument for this study is the K-SPRT(Kim's SIRT) and the I?eliability Coefficient ,4nalysis that was developed on this study. The mutts and the conclusicns was based on the data analysis are as follow: 1. The nrhiabitity coefficient of ikm has not influenced on the correctness of decision, in CAT with SPRT nxdel. 2. The reliability coefficient of items has influenced on the efficiency of decision, in CAT with SPRT model. 3. The reliability coefficient of items has influenced on the undecidedness, in CAT with SPRT model. 4. The undecidedness has influenced on the correctness of decision, in CAT with SFRT model.
Temperature Measurement Techniques for RAON Cryomodule
Kim, Heetae,Jung, Yoochul,Jo, Yong Woo,Lee, Min Ki,Choi, Jong Wan,Kim, Youngkwon,Kim, Juwan,Paeng, Won-Gi,Kim, Moo Sang,Jung, Hoechun,Kwon, Young Kwan The Korean Vacuum Society 2018 Applied Science and Convergence Technology Vol.27 No.2
Conducting and semiconducting temperature sensors are calibrated and applied to cryomodules. The definition of temperature is introduced and the pressure in vacuum is shown as a function of temperature. The resistance of Drude model is shown as a function of carrier density and mean free path. Temperature sensors are calibrated with Physical Property Measurement System (PPMS). The temperature sensors are applied to measure temperature accurately in RAON cryomodules.
Temperature Measurement Techniques for RAON Cryomodule
Heetae Kim,Yoochul Jung,Yong Woo Jo,Min Ki Lee,Jong Wan Choi,Youngkwon Kim,Juwan Kim,Won-Gi Paeng,Moo Sang Kim,Hoechun Jung,Young Kwan Kwon 한국진공학회(ASCT) 2018 Applied Science and Convergence Technology Vol.27 No.2
Conducting and semiconducting temperature sensors are calibrated and applied to cryomodules. The definition of temperature is introduced and the pressure in vacuum is shown as a function of temperature. The resistance of Drude model is shown as a function of carrier density and mean free path. Temperature sensors are calibrated with Physical Property Measurement System (PPMS). The temperature sensors are applied to measure temperature accurately in RAON cryomodules.
Introduction to Helium Leak Detection Techniques for Cryogenic Systems
Kim, Heetae,Chang, Yong Sik,Kim, Wookang,Jo, Yong Woo,Kim, Hyung Jin The Korean Vacuum Society 2015 Applied Science and Convergence Technology Vol.24 No.4
Many welding processes are performed to construct cryogenic system. Leak-tight for the cryogenic system is required at low temperature environment. Helium leak detection techniques are commonly used to find leak for the cryogenic system. The helium leak detection techniques for spraying, sniffing and pressurizing techniques are introduced. High vacuum is also necessary to use helium leak detector. So, types of fluid flow, effective temperature, conductance and pumping speed are introduced for vacuum pumping. Leak test procedure is shown for pipe welding, cryomodule and low temperature test. Cryogenic seals which include copper gasket, helicoflex gasket and indium are investigated.
Conservation of quality factor for superconducting cavities and mammals under relativistic motion
Kim Heetae 한국물리학회 2024 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.84 No.3
The conservation of quality factor under relativistic motion is applied to the superconducting cavities and the heartbeat of mammals. The total number of RF oscillation for superconducting cavities and that of heartbeat for mammals are conserved under relativistic motion. The frequency–energy relation is shown for the relativistic Doppler efect and energy conservation. The resonance frequency of the cavity decreases, and the decay time increases as the velocity and acceleration increase. The Q factor of the superconducting cavity is comparable to the total number of heartbeats of the mammal. The conservation of the Q factor for the heartbeat of the mammal, representing the total number of heartbeats, is also shown under relativistic motion. For mammals, the heart rate decreases, and the life expectancy increases as the velocity and acceleration increase.
Low Temperature Test of HWR Cryomodule
Kim, Heetae,Kim, Youngkwon,Lee, Min Ki,Park, Gunn-Tae,Kim, Wookang The Korean Vacuum Society 2016 Applied Science and Convergence Technology Vol.25 No.3
Low temperature test for half-wave resonator (HWR) cryomodule is performed at the superfluid helium temperature of 2 K. The effective temperature is defined for non-uniform temperature distribution. Helium leak detection techniques are introduced for cryogenic system. Experimental set up is shown to make the low temperature test for the HWR cryomodule. The cooldown procedure of the HWR cryomodule is shown from room temperature to 2 K. The cryomodules is precooled with liquid nitrogen and then liquid helium is supplied to the helium reservoirs and cavities. The pressure of cavity and chamber are monitored as a function of time. The vacuum pressure of the cryomodule is not increased at 2 K, which shows leak-tight in the superfluid helium environment. Static heat load is also measured for the cryomodule at 2.5 K.
HeeTae Kim,SangJib Kwon 한국교육개발원 2021 KEDI Journal of Educational Policy Vol.18 No.2
This study analyzes factors that influence the continuance intention of mobile learning (m-learning) for its users. We collected 222 responses from an online survey in South Korea. We conducted an empirical analysis by integrating the technology acceptance model and psychological factors related to learning. Subsequently, we verified the hypotheses drawn in this study using confirmatory factor analysis and structural equation modelling. The results show that perceived enjoyment, connectedness, and security, respectively, had a positive effect on the perceived ease of use and perceived usefulness of learning for users. Additionally, the results showed that perceived usefulness could be improved by increasing the perceived ease of use, which had a positive influence on learning satisfaction, learning self-efficacy, and continuance intention of m-learning, which were crucial to users’ learning outcomes. Particularly, learning self-efficacy, which was positively influenced by learners’ learning satisfaction, was also expected to boost the use of m-learning by influencing the continuance intention of m-learning. This study provided critical clues for expanding related research, and hence, this study has important implications for academic and practical purposes.