혼합형 검사에서 IRT문항모수와 기저 능력분포의 동시 추정이 문항모수 추정의 정확도에 미치는 영향

김성훈(Seonghoon Kim) 한국교육평가학회 2013 교육평가연구 Vol.26 No.3

본 연구는 김성훈(2012)의 후속연구로서, 혼합형 검사의 IRT 문항모수를 주변최대우도(MML)/베이지언 최빈치(BM)방법을 통해 추정할 때 사전능력분포를 ‘표준정규 N(0, 1)분포로 지정하는 방식’보다 ‘기저 능력분포의 추정치로 지정하는 방식(즉, 문항모수와 능력분포를 동시에 추정하는 방식)’이 더 우수한지를 모의실험을 통해 확인하고자 하였다. PARSCALE프로그램을 이용하여 혼합형 검사의 선다형 문항은 3모수 로지스틱(3PL)모형으로 분석하고 구성형 문항은 일반화부분점수(GPC)모형으로 분석하였다. 모의실험의 요인으로 기저 능력분포의 유형, IRT분석 모형에 의한 검사의 유형, 검사의 곤란도, 표본의 크기 등을 포함하였다. 김성훈(2012)의 연구 결과와 유사하게, 사전능력분포를 기저 능력분포의 추정치로 지정하는 방식이 디폴트 방식인 N(0, 1)분포로 지정하는 방식보다 고려된 모든 검사 조건에서 우수하거나 대등한 수행을 보였다. 즉, 선다형 검사뿐만 아니라 혼합형 검사에 대해서도 IRT 문항모수와 기저 능력분포의 동시 추정은 문항모수 추정의 정확성과 안정성을 향상시켰다. In item response theory (IRT), the use of marginal maximum likelihood (MML) and Bayesian modal (BM) methods for item parameter estimation requites the specification of a prior distribution for the ability variable. With multiple-choice (MC) tests, Kim (2012) found that in MML/BM estimation of item parameter; the way of specifying the prior ability distribution as the estimate of underlying distribution (i.e., concurrent estimation of item parameters and underlying distribution) outperformed or peformed equally to the way of specifying the prior ability distribution as a standard normal N(0, 1) distribution. As a follow-up study of Kim (2012), this paper attempted to verify through simulations that the previous findings from Me tests should be generalized to mixed-format tests consisting of MC items and constructed-response (CR) items. The PARSCALE program was used to analyze MC and CR items via the 3-paramerer logistic (3PL) and generalized partial credit (GPO models, respectively. The simulation factors considered include type of underlying ability distributions (normal, positively skewed, and negatively skewed), test type by the IRT model used OPL, GPC, and 3PL+GPC), test difficulty (easy, moderately difficult, and difficult), and sample size (500 and 2,000). As found in Kim's study, the way of concurrently estimating the underlying distribution along with item parameters outperformed or peformed equally to the way of specifying the prior distribution as a N(0, 1) in accurate estimation of item parameters with mixed-format tests.

열통합 기법을 통한 이산화탄소 막 분리공정 에너지 해석

김성훈,김태영,김범석,조현준,여영구,Kim, Seong Hun,Kim, Tae Yong,Kim, Beom Seok,Cho, Hyun-Jun,Yeo, Yeong Koo 한국플랜트학회 2016 플랜트 저널 Vol.12 No.2

이산화탄소 분리공정에 있어서 분리막 공정은 소형, 모듈성, 설치의 용이성, 작동의 유연성, 낮은 설치 비용 및 낮은 에너지 소비량 등의 장점들로 인하여 주목 받고 있다. 본 연구에서는 실험데이터와의 비교를 통해 교차흐름, 병류흐름, 향류흐름 3가지 모델의 정확도를 알아보았다. 실험에서 이용된 이산화탄소 분리공정을 가장 잘 나타내어주는 모델을 토대로 전산모사를 통하여 2단 막 분리 구조에서의 운전조건을 규명하고 분리막의 투과도 및 선택도가 분리성능에 미치는 영향을 알아보았다. 나아가 수증기 sweep을 이용하는 2단 막 분리 구조에서 열교환망 합성기법을 적용하여 열교환기 도입에 따른 소요 전력의 변화와 운전비용 절감효과를 살펴보았다. The membrane separation processes have received attention due to advantages such as compactness, modularity, ease of installation, flexibility of operation, lower capital cost and lower energy consumption. In this study, we evaluated accuracy of cross-flow, co-current and counter-current models. With the most accurate model, we identified the operating conditions of the two-stage membrane separation and examined the effects of permeance and selectivity of the membrane by simulation. Futhermore, power requirements and operating cost savings due to the introduction of the heat exchanger were investigated by applying heat exchanger network synthesis technique in the two-stage membrane separation using vapor sweep.

SELECT 모델을 이용한 트롤 비교 시험조업법에 의한 망목 선택성에 관한 연구

김성훈,김형석,백세나,김재형,김병관,Seonghun KIM,Hyungseok KIM,Sena BAEK,Jaehyung KIM,Pyungkwan KIM 한국수산해양기술학회 2023 수산해양기술연구 Vol.59 No.2

In this study, a comparative test operation was conducted through the alternate haul method to examine the selectivity of the four mesh sizes (60 mm, 90 mm, 110 mm, and 130 mm) of the trawl codend. The selectivity was analyzed using the SELECT model considering the fishing efficiency (split parameter) of each fishing gear in the comparative test fishing operation in the trawl and the maximum likelihood method for parameter estimation. A selectivity master curve was estimated for several mesh sizes using the extended-SELECT model. As a result of analyzing the selectivity for silver croaker based on the results of three times hauls for each experimental gear, it was found that the size of the fish caught increased as the size of the mesh size increased. When the selectivity for each mesh size analyzed by the SELECT model considering the split ratio was evaluated based on the size of the AIC value, the estimated split model was superior to the equal split model. Based on the master curve, the 50% selection length value was 2.893, which was estimated to be 136 mm based on the mesh size of 60 mm. In some selectivity models, there was a large deviance between observed and theoretical values due to the non-uniformity of the distribution of fished length classes. As a result, it is considered that appropriate sea trials and selectivity evaluation methods with high reliability should be applied to present trawl fishery resource management methods.

부신의 기능성종양 및 비기능성 부신피질선종을 제외한 부신 양성종양에 대한 임상적 고찰

김성훈,이준호,김지수,최준호,남석진,이정언,김석원,길원호,김정한,Sung Hun Kim,Jun Ho Lee,Jee Soo Kim,Jun-Ho Choi,Seok-Jin Nam,Jeong-Eon Lee,Seok Won Kim,Won Ho Kil,Jung-Han Kim 대한갑상선-내분비외과학회 2014 The Koreran journal of Endocrine Surgery Vol.14 No.4

Purpose: Benign adrenal tumors other than hyper-functioning tumor and non-functioning cortical adenoma are extremely rare. The purpose of this study is to review the clinical features of these rare benign adrenal tumors and to analyze their prevalence and the proper surgical approach for them. Methods: Among patients who underwent adrenalectomy in Samsung Medical Center, between 1997 and 2013, patients with benign adrenal tumor except non-functioning cortical adenoma, malignancy, and hyper-functioning tumor such as pheochromocytoma, aldosteronoma, and cortisol producing tumor were included. Clinical details, radiologic findings and pathologic findings as well as data associated with the surgical procedure were analyzed retrospectively. Results: The percentage of these tumors among 703 surgically removed adrenal tumors was 10.7% (75 cases). They included 30 adrenal cysts, 18 ganglioneuromas, 11 myelolipomas, seven schwannomas, and the other six were rare adrenal tumors. Approximately 40% of the patients were operated under a diagnosis different from original tumors. Operation time and hospital stay of patients who underwent laparoscopic adrenalectomy were shorter than those of patients who underwent open adrenalectomy. Conclusion: These benign adrenal tumors are very rare and difficult to diagnose preoperatively. For the surgical treatment of these tumors, laparoscopic adrenalectomy is more preferable to conventional open adrenalectomy.

열간가압소결법으로 제조한 탄화규소의 균열자기치유 특성

김성훈,김경훈,도환수,박주석,김경자,심광보,Kim, Seong-Hoon,Kim, Kyung-Hun,Dow, Hwan-Soo,Park, Joo-Seok,Kim, Kyung-Ja,Shim, Kwang-Bo 한국결정성장학회 2016 韓國結晶成長學會誌 Vol.26 No.2

본 연구에서는 열간가압소결법으로 SiC를 소결하여 균열자기치유 특성을 분석하였다. SiC는 $Al_2O_3$와 $Y_2O_3$를 소결조제로 $1950^{\circ}C$, 50 MPa, 아르곤(Ar) 분위기에서 소결하였다. 소결된 시편을 $3{\times}4{\times}40mm$, 절단 및 가공하고, Vickers 경도기를 이용하여 49.6 N으로 예비균열을 생성하였다. $1200{\sim}1400^{\circ}C$, 1~10시간 산화분위기에서 열처리한 후 XRD, SEM, 3점 굽힘강도를 측정하였다. $1300^{\circ}C$ 1시간에서 741 MPa, 5시간에서 770 MPa로 가장 우수한 균열자기치유 효과를 나타내는 것으로 분석되었다. In this study, it was investigated that characteristic of crack-self-healing of hot-pressed SiC. SiC ceramics was sintered with $Al_2O_3$ and $Y_2O_3$ sintering additive by hot press. Sintering was performed in hot-press furnace in flowing argon (Ar), holding for 3 hr under $1950^{\circ}C$ and 50 MPa. The sintered SiC was machined into 3-point bending strength specimen of $3{\times}4{\times}40mm$, and introduced pre-crack by Vickers indentation at 49.6 N. Specimens were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), 3-point bending strength after heat treatment at $1200{\sim}1400^{\circ}C$ for 1~10 hr. The best crack-self-healing ability was achieved 770 MPa 3-point bending strength by heat treatment at $1300^{\circ}C$ for 5 hr.

하천유역조사의 장기유출분석 과정 소개

김성훈,김선우,김태정,이성호,성장현,이연길,Kim, Seong-Hun,Kim, Seon-U,Kim, Tae-Jeong,Lee, Seong-Ho,Seong, Jang-Hyeon,Lee, Yeon-Gil 한국수자원학회 2020 물과 미래(한국수자원학회지) Vol.53 No.7

주조 포스트의 유지력에 관한 연구

김성훈,조혜원,진태호,Kim Sung-Hoon,Cho Hye-Won,Jin Tai-Ho 대한치과보철학회 1993 대한치과보철학회지 Vol.31 No.4

The purpose of this study was to evaluate the effects of method for construction of cast post and type of dental cement on the retention of cast post. The wax patterns or Duralay resin patterns were used for construction of cast post. The dental cements used in this study were zinc phosphate cement(Fleck's zinc cement, Mizzy INc., U.S.A.), glass ionomer cement(Fuji I, G-C Co., Japan), and resin cement(Panavia-EX, Kuraray Co., Japan) and the retention of cast post was measured with Instron Universal Test Machine(Instron Engineering Co., U.S.A.). The obtained results were as follows : 1. The tensile bond strength of cast posts made by Duralay resin patterns revealed 39.13(kg) with Panavia-EX, 46.40(kg) with phosphate cement, and 37.78(kg) with glass ionomer cement. 2. The tensile bond strength of cast posts made by wax patterns revealed 39.25(kg) with Panavia, EX, 44.12(kg) with phosphate cement, and 40.23(kg) with glass ionomer cement. 3. The tensile bond strength of cast posts made by Duralay resin patterns or wax patterns were not affected by the type of dental cements(P>0.05).

한.미 FTA가 유가공품 시장에 미치는 영향 분석: 치즈 및 버터 시장을 중심으로

김성훈,장도환,Kim, Seong-Hun,Jang, Do-Hwan 한국식품산업협회 2008 좋은식품 Vol.206 No.-

Recently, Korea have experienced numbers of FTAs with other countries, including Chile, EFTA(European Free Trade Association), Singapore, ASEAN(Association of South-East Asian Nations), and U.S. In particular, FTA with U.S. are expected to cause huge impact on food markets as well as agricultural sector in Korea. Many researches have analyzed and discussed about the impact on agricultural sector after Korean-U.S. FTA, but very small number of studies focus on the impact of Korean-U.S. FTA on food markets. The purpose of the paper is to discuss the impact of Korea-U.S. FTA on Korean dairy market. For the numerical simulations, this paper focus on the impact on cheese and butter markets. The results of numerical analysis in the paper will be helpful for the future research, because few (maybe no) studies conduct the numerical analysis to measure the impact of Korea-U.S. FTA on Korean food market.

생약복합제제 길경탕 및 가미길경탕의 항암효과 (제 1 보)

김성훈,박경식,유시용,Kim, Sung-Hoon,Park, Kyung-Sik,Ryu, Shi-Yong 한국생약학회 1996 생약학회지 Vol.27 No.1

The prescription, Kilkyungtang (KKT), which originally consists of twelve kinds of medicinal plant materials and was used as a decoction for the treatment of malignant tumors and two modified Kilkyungtangs (KKT-1 and KKT-2), supplemented by the additional crude drug to KKT (KKT-1:Houttuyniae herba, and KKT-2:Oldenlandiae diffusae herba) were investigated on their antitumoral properties, in vivo respectively. All KKTs were found to exhibit significant life time-prolonging effects when they were administered orally to Sarcoma-180 bearing ICR mice for 7 days. (ILS was estimated as 20% in KKT, 42% in KKT-1 and 57% in KKT-2). A profound lessening of tumor weights was also observed when KKTs were administered to $B16-F_0$ bearing C57B/6 mice.

Characteristics of Sympathetic Response in the Patients with Chronic Low Back Pain : A Comparative Study

김성훈,이계욱,박정미,이영희,김정문,Seong Hoon Kim,허동민 대한근전도전기진단의학회 2011 대한근전도 전기진단의학회지 Vol.13 No.2

Objectives: 만성 요통 환자에 대한 교감신경 피부반응의 신경전도검사와 임상증상의 상관성에 대한 연구는 거의 없는 상태이다. 이에 저자는 만성 요통 환자에서의 자율신경계반응을 평가하기 위해 상지에서의 교감신경 피부반응 검사를 시행하여 만성요통에서 자율신경계 기능부전에 대한 기초자료를 제공하고, 환자의 임상적 특성과 교감신경 피부반응과의 관계를 객관적으로 평가하여 교감신경 피부반응검사가 통상적인 근전도 검사에 부가적으로 진단 및 치료계획 수립에 대한 자료를 제공하고자 본 연구를 시행하였다. Methods: 본 연구에서는 3개월 이상의 이환 기간을 가진 만성요통환자 23명과 건강한 성인 23명을 대상으로 이학적 검사, 통증에 대한 시각적 상사척도, 일반 X 선 촬영, 컴퓨터 단층촬영 혹은 자기공명영상 촬영, 통상적인 침근전도 검사와 신경전도검사를 시행하였으며, 자율신경계에 대한 교감신경 피부반응검사를 시행하였다. Results: 교감신경 피부반응에 대한 각군간의 비교에서 환자군에서 대조군에 비해 진폭은 유의하게 감소된 소견을 보였으나(p<0.05), 잠시와 지속시간에서는 유의한 차이가 없었다(p>0.05). 근전도 검사 소견에 따른 교감신경 피부반응의 상관관계를 살펴보면 신경근병변과 정상 근전도 소견을 보인 두 군간에 교감신경 피부반응은 신경근병변 환자에서 잠시와 진폭이 감소된 소견을 보였으나 통계적으로유의하지는 않았다(p>0.05). Conclusion: 본 연구는 만성요통 환자에서 만성요통 각각의 임상적 특징에 따른 진단과 치료계획을 수립할 때 기초자료가 될 것으로 생각된다.