지가의 공간분포 분석을 통한 부산시 도시공간구조해석에 관한 연구

최창환(Choi Chang Hwan),이동본(Lee Dong Bon) 한국부동산학회 2005 不動産學報 Vol.25 No.-

1. CONTENTS (1) RESEARCH OBJECTIVES This study investigates the urban spatial structure which analyzes land distribution into its price in Busan. The land is limited resources, so the price and property of land are changed. It affects the urban spatial structure. Therefore it is important that the urban spatial structure was explained by using the price of land. (2) RESEARCH METHOD cluster analysis (3) RESEARCH RESULTS As result we realized that they have no relations between density of population and the price of land, but between the price of land and the distance from downtown have relations. The relations explained that farther place from downtown is lower price of land than a location which is near to downtown. 2. RESULTS The study reaches the two conclusion : first, the spatial structure of Busan was divided into two parts of inner functional space, a part of outer functional space and 7 parts of outer area. The second conclusion of the study is that the price of outer land is more expansive than center of city in some cases. 3. KEY WORDS the piece of land, urban spatial structure, Cluster Analysis, a economic zone

과민성 장증후군과 면역 활성화

최창환 ( Chang Hwan Choi ),설혜령 ( Hye Ryoung Sul ) 대한장연구학회 2008 Intestinal Research Vol.6 No.2

Irritable bowel syndrome (IBS) is a highly prevalent functional gastrointestinal disorder characterized by chronic abdominal pain and bowel habit change. Its specific pathophysiologic mechanism underlying IBS is not known; however, it is generally accepted that IBS symptoms represent dysregulation at multiple levels of the brain-gut axis. IBS symptoms are manifested by abnormal motor reactivity to various stimuli, and low sensation and pain thresholds. Recently, a variety of new findings have been reported which suggests low-grade inflammation or immune activation is present in IBS patients, including post-infectious IBS. The immune activation can generate various symptoms such as abdominal pain, bloating, and diarrhea that may result from motor dysfunction and visceral hypersensitivity. Anti-inflammatory therapy with either antibiotics or probiotics seems to be effective in reducing the symptoms of IBS. While this pathophysiologic approach to the management of IBS is in its infancy, it is evident that the immune activation deserves further attention in IBS. (Intest Res 2008;6:95-102)

진통소염제에 의한 위 십이지장 궤양에 합병된 위 출구 폐쇄 1예

최창환,변성환,장수희,백소야,Choi, Chang Hwan,Byun, Sung Hwan,Chang, Soo Hee,Paik, So Ya 대한소아소화기영양학회 2005 Pediatric gastroenterology, hepatology & nutrition Vol.8 No.2

저자들은 11개월 영아의 고열을 조절하기 위해 진통소염제 근주와 경구 해열제 병용투여 후 발생한 다발성 식도 위 십이지장 궤양 치료 과정 중 조기에 위 출구 폐쇄가 합병된 1예를 경험하였기에 보고하는 바이다. Peptic ulcer disease complicated with gastric outlet obstruction is rare in children. Even though NSAIDs have been reported to cause various adverse events, they are still regarded as safe and, therefore, widely utilized in children. In the past, pediatric patients who were at risk of seizure due to high fever, were treated with dipyrone (Metamizole sodium) injection which inhibits cyclooxygenase-1 and inhibit prostaglandin, to weaken the gastro-duodenal defensive mechanism. A case of an infant with multiple esophagogatroduodenal ulcers and bleeding caused by NSAID complicated with gastric outlet obstruction is reported in this paper.

기전 시스템의 구동 모터 선정 방법과 견마로봇용 지뢰탐지 구동 장치에의 적용

최창환,정승호,김석환,이정엽,최덕선,정상철,박용운,Choi, Chang-Hwan,Jung, Seung-Ho,Kim, Seok-Hwan,Lee, Jeong-Yeob,Choe, Tok-Son,Chung, Sang-Chul,Park, Yong-Woon 한국군사과학기술학회 2007 한국군사과학기술학회지 Vol.10 No.4

This paper presents a motor selection technique for a manipulator design that is used in a multipurpose dog-horse robot. Since the dynamics of a manipulator and its servo drives are closely related to each other, it requires a repetitive analysis to determine a suitable motor. In order to simplify this procedure, Straete et al. proposed a simple normalization method to separate the load dependent terms and the motor dependent terms. This technique is adopted in this paper for selecting a motor in designing a manipulator.

수복재료와 임플랜트 종류에 따른 임플랜트 및 지지조직의 응력분포

최창환,오종석,방몽숙,Choi Chang-Hwan,Oh Jong-Suk,Vang Mong-Sook 대한치과보철학회 2002 대한치과보철학회지 Vol.40 No.1

This study was aimed to analyze the stress distribution of implant and supporting tissue in single tooth implant restoration using Branemark $system^{(R)}$(Nobel Biocare, Gothenberg, Sweden) and Bicon system(Bicon Dental Implants, Boston, MA). Two dimensional finite element analysis model was made at mandibular first premolar area As a crown materials porcelain, ceromer, ADA type III gold alloy were used. Tests have been performed at 25Kgf vertical load on central fossa of crown portion and at 10Kgf load with $45^{\circ}$ lateral direction on cusp inclination. The displacement and stresses of implant and supporting structures were analyzed to investigate the influence of the crown material and the type of implant systems by finite element analysis. The results were obtained as follows : 1. The type of crown material influenced the stress distribution of superstructure, but did not influence that of the supporting alveolar bone. 2. The stress distribution of ceromer and type III gold alloy and porcelain is similar. 3. Stress under lateral load was about twice higher than that of vertical load in all occlusal restorative materials. 4. In Bicon system, stress concentration is similar in supporting bone area but CerOne system generated about 1.5times eater stress more in superstructure material. 5. In Branemark models, if severe occlusal overload is loaded in superstvucture. gold screw or abutment will be fractured or loosened to buffer the occlusal overload but in Bicon models such buffering effect is not expected, so in Bicon model, load can be concentrated in alveolar bone area.

지역통상정보 : 무역,ODA,FDI가 남미 경제발전에 미치는 영향 분석: 4개국 비교를 중심으로

최창환 ( Chang Hwan Choi ) 한국통상정보학회 2015 통상정보연구 Vol.17 No.3

본 연구에서는 공적개발원조(ODA), 해외직접투자(FDI), 수출과 수입 등 무역이 남미 경제발전에 어떠한 영향을 미치는지를 실증 분석하고자 하였다. 1960년∼2014년까지 자료를 기반으로 실증분석 결과 브라질은 ODA 보다는 FDI와 무역이 경제성장에 지대한 영향을 미친 것으로 확인되었고, 아르헨티나는 FDI, ODA가 긍정적인 영향을 주었고, 베네주엘라, 페루의 경우에는 ODA가 FDI가 무역보다 더 경제성장에 큰 영향을 준 것으로 확인되었다. 이러한 실증분석 결과를 바탕으로 우리가 알 수 있는 것은 저개발국가의 경제성장을 위한 선진국들의 정책지원이 경제성장 단계에 따라 다르게 시행되어야 한다는 것이다. 경제발전 초기인 경우 ODA를 증대하여 경제성장의 기반을 조성하는 것이 필요하고, 경제성장의 도약기인 경우에는 FDI나 무역증대를 통해 경제성장을 촉진하는 정책실행이 중요하다는 시사점을 도출하였다. This paper investigates how ODA·FDI·Trade affect economic growth in 4 South America countries over the last 50 years and ODA, FDI, Trade have a impact on the 4 South America countries economic growth using the Vector Error Correction Model. The results of empirical analysis based on data from 1960 to 2014 confirmed that FDI and trade than ODA has had a significant impact on Brazil and FDI, Trade had affected on Argentina economic growth. On the other hand, ODA had a more major impact on Venezuela,Peru economic growth than FDI and trade. Based on the results of these empirical analysis, when it comes to support for economic growth of underdeveloping countries, developed countries have to supply enough ODA for least developing countries to start economic growth, in case of economic take off stage, they should consider FDI, and international trade volume increase.

폐색전 제거술 후 혈전에서 우연히 확인된 원발 미상 편평 상피 세포암

최창환 ( Chang Hwan Choi ),박영수 ( Young Soo Park ),류동렬 ( Dong Ryeol Ryu ),박성하 ( Sung Ha Park ),고원기 ( Won Ki Ko ),안강현 ( Kang Hyun Ahn ),박재민 ( Jae Min Park ),김세규 ( Se Kyu Kim ),장준 ( Joon Chang ),김성규 ( Sung 대한결핵 및 호흡기학회 1999 Tuberculosis and Respiratory Diseases Vol.47 No.1

궤양성 대장염 치료 가이드라인

최창환 ( Chang Hwan Choi ),김영호 ( Young Ho Kim ),김유선 ( You Sun Kim ),예병덕 ( Byong Duk Ye ),이강문 ( Kang Moon Lee ),이보인 ( Bo In Lee ),정성애 ( Sung Ae Jung ),김원호 ( Won Ho Kim ),이희영 ( Hee Young Lee ) 대한소화기학회 2012 대한소화기학회지 Vol.59 No.2

Ulcerative colitis (UC) is a chronic inflammatory bowel disorder characterized by a relapsing and remitting course. The quality of life can decreases significantly during exacerbations of the disease. The incidence and prevalence of UC in Korea are still lower than those of Western countries, but have been rapidly increasing during the past decades. Various medical and surgical therapies are currently used for the management of UC. However, many challenging issues exist and sometimes these lead to differences in practice between clinicians. Therefore, Inflammatory Bowel Diseases (IBD) Study Group of Korean Association for the Study of Intestinal Diseases (KASID) set out the Korean guidelines for the management of UC. These guidelines are made by the adaptation using several foreign guidelines and encompass treatment of active colitis, maintenance of remission and indication for surgery in UC. The specific recommendations are presented with the quality of evidence. These are the first Korean treatment guidelines for UC and will be revised with new evidences on treatment of UC.

태권도 능력평가의 적절성 검토: 멀티미디어형 태권도 지식검사 활용

최창환(Chang Hwan Choi),이재봉(Jae Bong Lee),박재현(Jae Hyeon Park),김혜진(Hyeoi Jin Kim) 한국체육측정평가학회 2010 한국체육측정평가학회지 Vol.12 No.1

이 연구는 멀티미디어형 태권도 지식검사를 활용하여 동급 태권도 유단자가 동등한 태권도 지식수준을 가지고 있는지 확인함으로써 현행 태권도 능력평가의 적절성을 검토하는 것이 목적이다. 이 목적을 위하여 121명의 학생 (대학생 태권도 선수 49명, 태권도학과 대학생 31, 고등학생 태권도 선수 41명)을 임의선정 하였다. 임의선정의 기준은 태권도 수련기간이 7년 이상이면서 태권도 등급이 4단의 유단자로 정하였다. 측정을 위하여 멀티미디어 기반의 40개 태권도 지식검사 문항(기본동작, 겨루기, 품새, 시범에서 각 10문항)을 개발하였으며 태권도 및 측정평가 전문가 집단의 내용검토가 이루어졌다. IRT 1모수 다국면 Rasch 모형을 적용하여 태권도 지식검사 영역에서의 능력추정이 이루어졌으며 Facets 4.0(Linacre, 1994) 프로그램을 이용하여 분석이 이루어졌다. 이때 유의도 수준은 .05로 설정하였다. 전체적으로 태권도학전공자가 logit .10으로 대학태권도선수 -.02와 고등태권도선수 -.08로 χ2 6.6으로 p=.03 수준에서 통계적으로 유의한 차이가 있는 것으로 나타났다. 기본동작을 포함하여 겨루기, 품새 그리고 시범의 영역에서 모두 태권도학전공자가 선수집단(대학생 및 고등학생)에 비해서 태권도 4단의 동급 평가임에도 불구하고 높은 태권도지식수준을 나타내었다. 태권도관련 단순지식, 이해도, 응용력으로 구분된 검사유형에서 응용력은 태권도학전공자(logit=.11)와 고교선수(logit=-.19) 그리고 대학선수(logit=-.30)의 순으로 나타났다(χ2 6.9, p =.03). 그러나 태권도관련 단순지식과 이해도는 세 집단간 차이가 없는 것으로 나타났다. 결론적으로 태권도 동급 유단자이더라도 태권도관련 지식수준은 차이가 있는 것으로 나타나 현행 태권도 능력평가(승단심사)제도는 태권도 지식수준을 반영하지 못하고 있음을 시사해준다. 따라서 태권도 관련 표준화된 지식검사를 통한 능력평가는 태권도 유단자의 질 및 권위의 관리에 도움이 될 수 있을 것으로 판단된다. The purpose of this study is to test the appropriateness of the assessment on taekowndo abilities using the test items based on multimedia contents. For this study, 121 students (49 taekowndo players on university level, 31 students on studying taekowndo at univ., and 41 taekowndo players on high school level) were recruited by optional selecting method in Seoul and Kyung-Ky area, Korea. A selecting rules for this study considered by career of training duration and fourth Dan of taekowndo ability level. 40 items based on multimedia for taekowndo knowledge test were classified into four domains (basic motion, kyorugi, poomsae, and demonstration of taekowndo) by experts of taekowndo and measurement specialists. A difficulties of items and abilities of students were calculated using Rasch model of item response theory(IRT). The result of this study shows that there are statistically significant difference (χ2 6.9, p=.03) among players on university level(logit=-.30), majoring students of taekowndo(logit=.11), and players on high school level(logit=-.19). In conclusion, we can consider testing of knowledges of taekowndo for assessing taekowndo abilities.

철근 공장가공화를 위한 철근 스프링 백에 대한 수치적 연구

최창환(Choi, Chang-Hwan),김진호(Kim, Jin-Ho),이성규(Lee, Sung-Kyu) 한국산학기술학회 2013 한국산학기술학회논문지 Vol.14 No.8

현재 공사현장에서 사람이 직접 기계로 철근 굽힘 가공을 하고 있다. 하지만 사람이 직접 기계로 가공하기 때문에 정밀성이 떨어지고 시간이 많이 소요된다. 이를 공장가공방식으로 자동화하여 정밀성과 가공성을 높이기 위해 서는 스프링 백 현상을 분석해야한다. 이 현상은 굽힘 공정 이 후 하중제거에 따른 재료의 복원 능력이 발생하여 원 래의 요구하는 형상에서 벗어나게 하며 이는 굽힘 각도, 굽힘 반경, 철근의 직경에 영향을 받는다. 우리는 굽힘 각, 굽힘 반경, 철근의 직경을 스프링 백 현상에 영향을 미치는 인자로 정하고 FEM을 통해 각 인자들이 철근 굽힘 가 공에 미치는 영향에 대한 경향성을 분석하였다. 그 결과 굽힘 각도 10°씩 증가함에 따라 약 0.1°씩 스프링 백 현상이 커졌으며 철근 직경은 φ10mm에서 φ16mm로 증가함에 따라 약 0.6° 증가하였다. 반면 굽힘 반경은 30mm에서 40mm로 증가함에 따라 스프링 백 각도가 약 0.2° 줄어드는 현상을 확인할 수 있었다. These days, workers in a construction site conduct a rebar bending process with a machine. This bending process has some problems such as long processing time and bad quality of the rebar. In order to manufacture a rebar having precision and machinability, we should study on Spring-back phenomenon. This phenomenon affects a shape of rebar after unloading due to restoration ability of material and it is influenced by bending angle, bending radius and a rebar diameter. The change of spring-back ratio according to the change of the parameters are analyzed by FEM. Consequently, Spring-back increases around 0.1° as bending angle increases 10°. and it also increases around 0.6° as diameter of rebar increases from φ10mm to φ16mm. while we can confirm that it decreases around 0.2° as bending angle increases 10°.