분산전원을 고려한 배전계통의 개선된 보호협조 방안 연구

최동만(Choi Dong Man),최준호(Choi Joon Ho),문승일(Moon Seung Il),김재철(Kim Jae Chul),문채주(Moon Chae Joo),김일수(Kim Il Soo) 전력전자학회 2005 전력전자학술대회 논문집 Vol.- No.-

Recently, There has been growing interest in Distributed Generations with high-energy efficiency due to the increasing energy consumption and environmental pollution problems. but an insertion of Distributed Generations to existng power distribution system can cause several problems such as voltage variations, harmonics, protective coordination, increasing fault current etc, because of reverse power. This paper was applied to Sukumar M[1] proposal schemes and identily the faulted section performing short-circuit analysis by MATLAB program to distribution systems interconnected a large number of distributed generations.

화장품 서브스크립션 커머스를 사용하는 소비자의 구매의사결정과정에 관한 질적연구

최동은(Dong-Eun Choi),황선진(Sun-Jin Hwang) 한국인체미용예술학회 2015 한국인체미용예술학회지 Vol.16 No.4

This study examines purchase decision-making process by consumers who use the brand new subscription commerce. It attempted to determine why they use subscription commerce and what affect it has on beauty box consumers’ purchase behavior. For this, a qualitative research was conducted through an in-depth interview with five beauty box users and analysisof SNS and blog comments. Then, the results found the following. First, cosmetics subscription commerce consumers’ problem perception started with a sensitive response to trends and curiosity or a new product. The characteristics of the problem perception include sensitive response to trends, curiosity for a new produc, and frequent purchase of low-involvement products. Second, consumers’ information search was classified into inducement of purchase motivation by word of mouth, information collection, and excellent media utilization ability. Third, consumers’ alternative assessment was divided into clear awareness of the difference between an authentic product and sample, and clear grading and assessment by subscription commerce. Fourth, consumers’ purchase decision-making was classified into decision-making based on price and function, and impulse buy. Lastly, post-purchase behavior included the use of a new product, disposal of the product, self-compensation, and inducement of motivation to use different subscription commerce. It appears that the results would be the basis for new marketing that would emerge in the SNS market that has rapidly evolved in a diverse and complicated manner as well as be a foundation for future subscription commerce-related studies.

담관암의 원인으로서의 간흡충과 담석

최동일 ( Dong Il Choi ),임재훈 ( Jae Hoon Lim ) 대한간암학회 2010 대한간암학회지 Vol.10 No.-

C. sinensis induces adenomatous hyperplasia of the epithelium of the bile ducts, and the epithelium of the bile duct persistently exposed to biochemically altered bile may undergo the sequence, hyperplasia-metaplaisa-dysplasia-carcinoma. Cholangiocarcinomas were developed in most hamsters treated with an N-nitroso compound and then infected with C. sinensis. In the patients with intrahepatic duct stones, bile usually infected with bacteria. Mechanical stimuli due to stones, long-lasting bile stasis, and bacterial infection are considered to be the other significant causative factors in cholangiocarcinogenesis. Radiological examinations are essential in the diagnosis and treatment of biliary tree diseases including clonorchiasis, biliary stone disease, and cholangiocarcinoma. As both C. sinensis and intrahepatic duct stones are common, radiological and clinical findings should be attentively investigated for the possible presence of cholangiocarcinoma in patients with clonorchiasis or intrahepatic duct stones.

snO<SUB>2</SUB> 후막형 부탄가스 감지 소자

최동한(Dong-Han Choi),이덕동(Duk-Dong Lee),손병기(Byung-Ki Sohn) 대한전자공학회 1986 대한전자공학회 학술대회 Vol.1986 No.6

초등학교 스포츠강사의 좌절감 형성과정

최동일(Choi, Dong-Il),이근모(Lee, Keun-Mo) 한국체육과학회 2015 한국체육과학회지 Vol.24 No.2

The purpose of this study was to examine the process of sense of frustration of elementary school sports instructors and how those sense of frustration were formed. In order to accomplish the purpose of the study, qualitative study method was conducted, and 8 sports instructors from elementary school in B. city were selected as the object for study. In order to minimize subjective prejudice regarding environment, consultation with triangulation and experts were repeated numerously. For discussion with experts, through discussion with two sports instructors and two doctors of sports sociology whom can be of practical help to this study, the validity and credibility of the study were secured. The result drawn from this study is as follows. First, the ‘dual-licensed elementary school physical education teacher’ system of 1999 included in the sports instructor system that was first introduced to elementary schools in 2009 presented rosy hopes such as ‘elementary school physical education teacher’ and ‘elementary school teacher specialized in physical education’ to the people who hope to become sports instructors. Second, as years went by, sports instructors had to overcome the hardships and struggles in the reality of school. Third, they had the anxiety and fear for their positions that could be taken away if lay-offs of the sports instructors become a reality. Such anxiety and fear also made them to form sense of frustration by themselves thinking that the decision to become a sports instructor was their fault.

간세포암의 고주파열치료의 최신 기술적 발전들

최동일 ( Dong Il Choi ),임현철 ( Hyun Chul Rhim ),이민우 ( Min Woo Lee ) 대한간암학회 2012 대한간암학회지 Vol.12 No.1

Lots of recent technical advances in radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC) have introduced. First, contrast-enhanced ultrasound can help to detect the index tumors, residual tumor, and local recurrence. After contrast-enhanced ultrasound for subtle small tumors, we can perform RFA with high confidence. The use of artificial ascites in RFA is a simple and useful technique to minimize collateral thermal injury and to improve the sonic window. Fusion imaging between US and CT or MR during RFA is useful since US can provide real-time imaging and CT or MR provides high quality images with good contrast and spatial resolution. RFA can be performed with fluoroscopy guidance to lipiodol retention tumors.

화공 플랜트 산업에서의 건축 엔지니어링의 특성 및 절차

최동인(Choi, Dong-In),김지원(Kim, Ji-Won),서동환(Seo, Dong-Hwan) 대한건축학회 2014 建築 Vol.58 No.7

SAN으로 코팅된 PC/PTFE 복합체의 기계적 물성 및 난연특성

최동인(Dong In Choi),이영실(Young Sil Lee),윤관한(Kwan Han Yoon),김수완(Soo Wan Kim),하두한(Doo Han Ha) 한국고분자학회 2020 폴리머 Vol.44 No.6

본 연구에서는 스티렌(styrene)과 아크릴로니트릴(acrylonitrile)을 공중합하여 형성된 SAN을 폴리테트라플루오로에틸렌(PTFE) 입자의 표면에 코팅하여 core-shell 구조를 갖는 SAN-PTFE 나노 입자를 제조한 후 이를 폴리카보네이트(PC)에 분산시키기 위해 압출기를 이용하여 복합체를 제조하였다. SAN 중합용 개시제의 함량이 줄어들면 PTFE에 코팅된 SAN의 두께가 감소하였고 중합 시 PTFE의 함량을 늘려주면 역시 SAN 코팅 두께가 감소하였으며, 중합시간을 늘려주면 코팅 두께는 증가하였다. PTFE 8.3 phr을 함유하는 PC/SAN-PTFE 복합체의 경우 인장강도와 충격강도는 PC와 같은 57 MPa과 48 J/m이 얻어졌고 인장탄성률은 오히려 PC보다 7% 증가하였다. 그러나 PTFE를 포함하는 PC/PTFE 복합체의 경우는 충격강도를 제외하고 인장강도와 인장탄성률 모두 PC의 값보다 감소하였다. PTFE 8.3 phr을 함유하는 PC/SAN-PTFE 복합체의 한계산소지수(LOI)는 28.1%를 나타내었다. Core-shell structured SAN-PTFE composites were prepared by grafting styrene and acrylonitrile copolymer (SAN) onto the surface of polytetrafluoroethylene (PTFE) and compounded with polycarbonate (PC) using co-rotating twin extruder. Coating thickness of the shell decreased with decreasing of initiator and increasing of PTFE content, and increased with the polymerization time of SAN copolymer. The tensile and impact strength of PC/SAN-PTFE (8.3 phr) composite were 57 MPa and 48 J/m, respectively, which are similar values of PC. The tensile modulus of the composite was rather 7% higher than that of PC. However, the tensile strength and modulus of PC/PTFE composite were lower than those of PC while the impact strength of PC/PTFE was maintained as almost same value of PC. The limiting oxygen index (LOI) of PC/SAN-PTFE composite containing 8.3 phr of PTFE was determined to be 28.1%.

옻의 특징과 옻을 지지재로 사용한 전자파 흡수체의 두께에 따른 흡수 특성 분석

최동한(Dong Han Choi),김동일(Dong Il Kim),김기만(Ki Man Kim) 한국항해항만학회 2004 한국항해항만학회 학술대회논문집 Vol.1 No.-

고성능 복합형 전자파 흡수체를 개발하기 위해 종래에는 지지재로서 주로 Silicone 고무나 CPE가 사용되어왔다. 본 연구에서는 전통 공예에서 사용되어 오던 옻에 대한 특징을 분석하고 옻의 전자파 흡수능을 조사하고 이를 지지재로 사용하여 MnZn 페라이트와 배합하여 전자파 흡수체를 제작한 경우의 전자파 흡수능을 조사하고, 흡수체의 두께에 따른 흡수능을 조사하였다. 옻을 지지재로 한 MnZn 페라이트 복합형 전자파 흡수체는 CPE나 Silicone 고무줄 지지재로 한 전자파 흡수체에 비하여 우수한 전파흡수특성 나타내었으며, 옻을 지지재로 사용한 전파흡수체의 두께 변화에 따라 정합주파수와 전파흡수능이 변화함을 알았다. Generally, a silicone rubber and a chloride polyethylene(CPE) have been for the development of high-performance composite EM(ElectroMagnetic) wave absorbers. In this study, the EM wave absorption abilities for natural lacquer which is newly suggested in this study as a binder for composite EM wave absorbers were investigated to develop an improved EM wave absorbers. In addition, MnZn ferrite composite EM wave absorbers mixed with the natural lacquer were prepared and their absorption ability was also investigated. MnZn ferrite composite EM wave absorption characteristics in comparison with the conventional binder such as a silicone rubber and a chloride polyethylene(CPE). The matching frequency and the absorption ability of EM wave absorbers mixed with natural lacquer can be controled the change of the thickness of them.

중증장애인의 보조기기 서비스 이용과정에 관한 사례비교 연구 : 거주유형 및 서비스 이해관계자 중심으로

최동일(Dong-il Choi),배영현(young-Hyeon Bae),송원경(Won-Kyung Song),이범석(Bum-Suk Lee) 한국사회복지학회 2020 한국사회복지학회 학술대회 자료집 Vol.2020 No.10

본 연구는 중증장애인의 보조기기 서비스 이용과정에 관하여 거주유형 및 서비스 이해관계자를 중심으로 중증장애인별 사례비교를 통해 실제 보조기기 서비스 이용과정에 대한 이해를 높이고 제한점을 파악하여 수요자 중심의 통합적인 보조기기 서비스 이용 방안을 제시하고자 한다. 본 연구는 질적 사례연구인 개별 면담을 이용해 중증장애인 4명을 대상으로 거주공간 정보, 이해관계자 정보, 사용하고 있는 보조기기에 대한 정보 수집 경로, 보조기기 공적급여 이용 정보, 자부담을 통한 보조기기 획득 경로, 보조기기 사용 교육 및 관리안내, 보조기기 활용 목적 등 보조기기와 관련된 종합적인 내용을 파악하였다. 사례별 면담내용을 기반으로 보조기기 사용자와 이해관계자 간 상호관계를 한눈에 볼 수 있도록 이용과정을 도식화하였고 이용과정 비교분석을 통해 중증장애인별 거주유형에 따른 서비스 이해관계자(이용자, 생산자, 서비스기관, 의사 결정기관 등) 유형 및 역할의 차이를 확인하였으며, 수요자 중심의 통합적인 보조기기 서비스 이용과정 방안을 제시하였다. This study is to analysis of the process of using the assistive technology service with focusing on type of residence and service stakeholder on Severe Disability Persons for providing comprehensive assistive technology service. This case study was used the individual interview with information of stakeholder, residence, process and management of using assistive technology for 4 severe disability persons. Based on the results of interviews by case, the process of the assistive technology service was illustrated so that the relationship between the type of residence and service stakeholder. Also, through the comparative analysis of process of using assistive technology service, there were to confirm the differences in the process of using assistive technology service and provide comprehensive assistive technology service for improving activities of daily living and quality of life in severe disability person.