• 대순사상논총
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• 제35집
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• pp.217-253
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• 2020

이 연구는 선경(仙境)과 음양합덕, 그리고 천지공사(天地公事)의 원리를 분석하여 조선 미술과 접목하는 입장이다. 이에 대순진리의 태극 사상이 조선 미술에 깊숙이 스민 정황을 찾아내는 연구이다. 이로 말미암아 한민족의 생활이나 습속에 내재한 대순사상이 어떻게 비치는지 파헤친다. 아울러 한민족의 정서나 사상이 어떤 모습인지 대순사상과 창작품을 바탕으로 검토하는 데 따른다. 더욱이 대순사상이 학예에 파고든 정황을 우주론 차원에서 입증하는 데 따른다. 이에 부응한 연구 목적은 대순사상이 내세우는 핵심을 시각 이미지로 생생하게 들춰내는 일이다. 이로써 대순사상과 조선 미술의 결합에 부합하는 문헌과 더불어 실재성을 동시에 확보한다. 그 일환으로 이 연구는 우주론에 입각한 태극 원리로써 대순사상의 세계를 다룬다. 이러한 사상 개념은 조선 미술에 고스란히 드러나는데, 이를 예술 철학 입장에서 분석하여 점검한다. 우선 대순사상을 해결하려는 방안으로 대순진리를 개진하고 이를 조선 미술과 직접 접목한다. 이로써 대순사상이 한국인의 삶에는 어떻게 비치는지 밝힌다. 이와 관련하여 조선 미술의 선정 방법은 민중 생활에 깊숙이 파고든 창작품을 선별한다. 가령 대순사상이 조선조의 풍속화, 민화, 산수화에 집중하여 나타나는 만큼 이를 단서로 입증과 검증 절차를 시각화하여 다룬다. 이 연구는 조선 미술에 스민 대순사상을 예술 철학 차원에서 분석하는 일이다. 이에 따라 음양합덕과 태극 사상이 조선 미술에 내재한 상황을 찾아내는 시도는 대순사상이 민중과 동화한 정황을 들추는 근거이다. 더불어 조선 미술에서 대순사상을 점검하는 일은 조선 미술의 양식뿐만이 아니라 한민족의 생활과 의식, 그리고 정신세계를 생생하게 확인할 기회이다. 그 일환으로 2장에서는 대순사상의 형성을 밝혔다. 3장에서는 '선경(仙境)'과 '음양합덕' 사상의 구조, 그리고 '천지공사(天地公事')와 '태극' 사상을 우주의 운행 법칙에 기인하여 밝혔다. 이에 천지공사의 운행 법칙과 태극 구조를 접목했다. 4장에서는 대순사상과 조선 미술의 융합 차원에서 한민족의 삶과 더불어 창작품에 나타난 대순사상을 분석했다. 이른바 창작품 분석은 실증 자료로 드러내는 데에는 유용한 효과인 만큼 조선 미술에 배인 대순사상을 정밀하게 밝힐 단서이다. 이를테면 <금강전도>, <금강내산전도>, <쌍검대무>, <쌍치도>, <주사채부적도>, <화조기명화분도>, <문자도>에서 선경, 음양합덕, 천지공사의 이치를 분석 대상으로 삼았다. 그 결과 대순사상에 나타난 태극 사상이 조선 미술에 고스란히 스민 정황을 입증했다. 이 모든 진술을 감안할 때, 대순진리가 추구하는 태극 사상은 만물이 상호 생성하면서 변화를 따르는 섭리이다. 그런즉 태극 사상은 한민족의 삶에 지대하게 자리하여 '상생(相生, Mutual life-saving, mutual life-bettering)'으로 융화하는 섭리에 상호 응대한다는 점을 도출했다.

• 한국조경학회지
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• 제51권3호
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• pp.70-82
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• 2023

최근 IT 기술과 데이터의 범람으로 생활 전반적인 부분의 패러다임이 전환되고 있다. 이러한 기술의 발전과 변화는 학술영역에도 영향을 미치고 있다. 학문적 교류와 연계를 통해 연구주제나 연구 방법의 개선이 이루어지고 있다. 특히, 데이터 기반의 연구 방법이 다양한 학문분야에서 진행되고 있으며 조경학에서도 지속적인 연구가 필요한 시점이다. 따라서 본 연구에서는 이러한 시대적 상황을 반영하여 인공지능의 한 분야인 머신러닝을 활용한 경관 선호 평가 및 예측모델의 개발 가능성을 알아보는 것을 목표로 한다. 본 연구의 목표를 달성하기 위하여 경관 분야에 머신러닝 기법을 적용하여 경관 선호 평가 및 예측 모델을 구축하고, 구축된 모형의 모의정도를 검증하였다. 이를 위해 본 연구에서는 최근 신재생에너지 사업으로 주목받는 풍력발전시설 경관 이미지를 연구대상으로 선정하였다. 분석을 위하여 풍력발전시설 경관 이미지를 웹크롤링 기법을 활용하여 수집하고 분석 테이터셋을 구축하였다. 우수한 성능의 예측모델 도출을 위하여 머신러닝 분석에 활용되는 University of Ljubljana의 프로그램인 오렌지 버전 3.33을 활용하였다. 또, 머신러닝 학습데이터의 평가기준을 통합한 모델과 평가기준 별도 모델 구조를 활용하였으며, 머신러닝 분류모델에 적합한 kNN. SVM, Random Forest, Logistic Regression, Neural Network 알고리즘을 사용해 모델을 생성하였다. 생성된 모델을 성능 평가를 실시하여 본 연구에 가장 적합한 예측모델을 도출하였다. 본 연구에서 도출된 예측모델은 경관의 유형에 따른 분류, 경관과 대상의 시거리에 따른 분류, 선호에 따른 분류 등 3가지 평가기준을 별도로 평가 후 종합해 예측하여 결과를 도출하였다. 연구 결과 경관 유형에 따른 평가 기준 정확도 0.986, 시거리에 따른 평가 기준 정확도 0.973, 선호에 따른 평가 기준 정확도 0.952에 달하는 높은 정확도를 가진 예측모델을 개발하였으며, 평가데이터 예측 결과를 통한 검증과정을 보아도 모델의 성능 치를 상회하는 성과를 도출했음을 알 수 있다. 경관 관련 연구에서 머신러닝을 활용한 예측모델 개발 가능성을 알아본 실험적 시도로 이미지 데이터의 수집 및 정제를 통해 데이터 세트를 구축하여 높은 성능의 예측모델이 생성 가능하며, 이후 경관 관련 연구 분야에 활용될 수 있다는 가능성을 확인할 수 있었다. 본 연구의 결과와 시사점, 한계점을 반영한다면 풍력발전시설의 경관뿐만 아니라 자연경관이나 문화경관 등 다양한 형태의 경관 예측모델 개발이 가능할 것으로 생각되며, 경관 유형에 따라 이미지를 분류하는 모델의 연구를 통해 데이터 분류의 시간을 단축하거나 머신러닝을 활용한 경관예측 인자분석을 통해 경관계획 요소의 중요도 분석 등의 주제에 맞는 연구 방법을 탐색하고 적용하여 후속 연구를 진행한다면 조경학 분야에서도 머신러닝 기법을 보다 유용하고 가치 있게 활용할 수 있을 것으로 생각된다.

• Asia Marketing Journal
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• 제14권2호
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• pp.127-156
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• 2012

본 연구에서는 가족 내 높은 의사결정권을 가진 베이비부머세대 중년여성을 연구대상으로 선정하여 이 소비자에 대한 이해를 높이기 위해 이들이 삶에서 추구하는 가치를 질적연구방법을 통해 알아보았다. 그 결과, 시간, 관계, 젊음과 건강, 자아실현, 의식의 총 5개의 핵심가치를 도출했다. 상위범주들의 맥락적 관계를 구축하여 모형을 도출한 결과, 베이비부머세대 중년여성은 시간적 여유의 증가와 이전/이후세대와는 다른 의식을 인과적 조건으로 하여 자아실현과 타인과의 관계맺기 현상을 나타내며 이 과정에서 스트레스를 받고 있었다. 이들은 이와 같은 현상을 대처하기 위해 건강과 젊음을 위해 다양한 노력을 취하고 있었으며, 이를 통해 최종적으로 시간적 여유가 있고 경제적으로 크게 고통 받지 않는 현재의 삶에 감사하고 있다는 결론을 도출하였다. 모형을 보다 추상적인 중심현상으로 축약화하여 베이비부머세대 중년여성의 삶에 대한 이야기를 구성하였으며, 이를 통해 베이비부머 중년여성이 여러 가지 활동과 노력을 통해 추구하고자 하는 것은 '건강하고 젊고 행복한 삶'이라는 결론을 내렸다. 본 연구를 통해 도출된 실무적 시사점은 다음과 같다. 첫째, 베이비부머세대 중년여성의 삶에 가장 큰 영향을 미치는 시간을 잘 활용하도록 도와주는 상품, 서비스가 필요하다. 둘째, 자아실현 욕구가 높은 베이비부머세대 중년여성이 자아효능감을 느낄 수 있도록 이들의 감각, 능력, 인맥을 활용할 수 있는 기회를 제공해야 한다. 셋째, 이들의 집안과 외모 가꾸기는 자아실현의 방법이므로 이 시장에 대한 세분화가 필요하다. 질적인 방법으로 진행된 본 연구의 한계점을 보완하기 위해서는 다양한 지역과 소득계층을 포함하는 후속연구가 진행되어야 한다. 그리고 이상의 결과를 확인하고 보완하는 차원의 양적연구가 후속으로 진행되어야할 것이며, 이들 삶의 한 부분을 집중적으로 조명하여 더욱 깊이 있는 결과를 도출하는 후속연구가 필요하다.

• Tuberculosis and Respiratory Diseases
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• 제46권2호
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• pp.215-228
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• 1999

배 경: 유육종증은 원인 모르게 비건락성 상피성 육아종이 전신에 발생하는 질환으로서 그 경과가 매우 다양하여 많은 환자들은 자연적으로 치유되기도 하나 일부 환자들은 계속 진행하여 호흡부전으로 사망하기도 하며 이러한 다른 결과가 초래되는 기전이나, 그 결과를 예측하는 지표는 아직 알려진 것이 없다. 유육종증은 병변내에서는 CD4+ T 임파구가 수적으로 증가할 뿐 아니라 그 작용이 과다하게 증가하며 이러한 병변내에서의 CD4+ T 임파구의 과다한 작용은 정확한 원인은 아직도 모르지만 이들이 oligoclonality를 가진 것으로 미루어 어떤 항원의 지속적인 자극에 기인할 것으로 추측하고 있다. 근래에 CD4+ T 임파구가 주로 IL-2 및 IFN-$\gamma$을 분비하고 지연성 과민 반응에 기여하는 Th1 세포와 IL-4, IL-5, IL-10을 분비하여 알레르기 반응에 관여하는 Th2 세포의 두 종류가 있다는 것이 밝혀졌고, 유육종증 병변 내 CD4+ T 임파구는 IL-2 및 IFN-$\gamma$를 분비하는 Th1 세포가 주인것으로 생각되고 있다. 또한 최근 미분화 T 세포들을 Th1 세포쪽으로 분화를 유도하는 데에 IL-12가 중요한 역할을 한다는 것이 알려졌으며, Mmoller등은 폐유유종증 환자에서 기관지폐포세척액(Bronchoalveolar lavage fluid : BALF) 내 IL-12가 증가한 것을 관찰하였다. 그러므로 폐유육종증의 병변의 계속적인 진행, 또는 자연치유 여부의 결정에 IL-12가 관여할 것을 추측할 수 있다. 이에 저자들은 IL-12가 유육종증의 활동성 지표로 사용될 수 있는지를 알아보기 위하여 본 연구를 시행하였다. 대 상: 조직학적으로 확진된 폐유육종증 환자 26명(남자: 10명, 여자: 16명, 연령: $38.7{\pm}10.6$세)과 정상 대조군 11명을 대상으로 진단 시 얻은 BALF 내 IL-12양과 BALF내 폐포대식세포 (Alveolar macrophage : AM)를 24 시간 배양 시 배양액 내로 분비되는 IL-12양을 ELISA 방법으로 측정 비교하였다. 폐유육종증 환자들중 12명이 임상적으로 비활동성이었고, 14명은 활동성이었다. 결 과: 폐유육종증 환자들의 BALF내 총세포수, AM 총수, 임파구백분율 및 총수, CD4/CD8 비가 대조군에 비해 유의하게 증가하였으나, 활동성 및 비활동성 환자군 사이에 유의한 차이는 없었다. BALF내 IL-12 농도는 폐유육종종 환자에서 $49.3{\pm}9.2$ pg/ml로 정상대조군의 $2.5{\pm}0.4$ pg/ml 보다 유의하게 (p<0.001) 높았고, 활동성 유육종증에서는 $70.3{\pm}14.8$ pg/ml로 비활동성 환자들의 $24.8{\pm}3.1$ pg/ml 보다 유의하게 높았다(p=0.001). BALF내의 IL-12 농도는 BALF내 AM백분율 (p<0.001), 임파구 백분율 (p<0.001) 및 임파구 총수 (p<0.001)와도 유의한 상관관계를 보였다. 또한 BALF내의 IL-12 농도는 최근에 유육종증의 활동성의 지표로 알려지고 있는 혈청 및 BALF내 sICAM-1 농도(각각 p<0.001, p=0.001), AM의 ICAM-1 발현도와도 (p<0.001) 유의한 상관관계를 보였다. AM에서의 IL-12분비량은 폐유육종증 환자들에서 $206.2{\pm}61.9$ pg/ml로 정상대조군의 $68.3{\pm}43.7$ pg/ml 보다 높았으며 (p<0.008), 활동성 및 비활동성 환자군간 유의한 차이는 없었다. 결 론: 이상의 결과로 BALF 내 IL-12 농도는 폐내 염증 세포의 침윤 정도를 반영하며, 유육종증의 활성도를 예측하는 지표로서 유용할 것으로 사료되었다.

• 인터넷정보학회논문지
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• 제14권6호
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• pp.71-84
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• 2013

컴퓨터 시스템 운용 간에 발생하는 많은 정보들이 기록되는 로그데이터는 컴퓨터 시스템 운용 점검, 프로세스의 최적화, 사용자 최적화 맞춤형 제공 등 다방면으로 활용되고 있다. 본 논문에서는 다양한 종류의 로그데이터들 중에서 은행에서 발생하는 대용량의 로그데이터를 처리하기 위한 클라우드 환경 하에서의 MongoDB 기반 비정형 로그 처리시스템을 제안한다. 은행업무간 발생하는 대부분의 로그데이터는 고객의 업무처리 프로세스 간에 발생하며, 고객 업무 프로세스 처리에 따른 로그데이터를 수집, 저장, 분류, 분석하기 위해서는 별도로 로그데이터를 처리하는 시스템을 구축해야만 한다. 하지만 기존 컴퓨팅환경 하에서는 폭발적으로 증가하는 대용량 비정형 로그데이터 처리를 위한 유연한 스토리지 확장성 기능, 저장된 비정형 로그데이터를 분류, 분석 처리할 수 있는 기능을 구현하기가 매우 어렵다. 이에 따라 본 논문에서는 클라우드 컴퓨팅 기술을 도입하여 기존 컴퓨팅 인프라 환경의 분석 도구 및 관리체계에서 처리하기 어려웠던 비정형 로그데이터를 처리하기 위한 클라우드 환경기반의 로그데이터 처리시스템을 제안하고 구현하였다. 제안한 본 시스템은 IaaS(Infrastructure as a Service) 클라우드 환경을 도입하여 컴퓨팅 자원의 유연한 확장성을 제공하며 실제로, 로그데이터가 장기간 축적되거나 급격하게 증가하는 상황에서 스토리지, 메모리 등의 자원을 신속성 있고 유연하게 확장을 할 수 있는 기능을 포함한다. 또한, 축적된 비정형 로그데이터의 실시간 분석이 요구되어질 때 기존의 분석도구의 처리한계를 극복하기 위해 본 시스템은 하둡 (Hadoop) 기반의 분석모듈을 도입함으로써 대용량의 로그데이터를 빠르고 신뢰성 있게 병렬 분산 처리할 수 있는 기능을 제공한다. 게다가, HDFS(Hadoop Distributed File System)을 도입함으로써 축적된 로그데이터를 블록단위로 복제본을 생성하여 저장관리하기 때문에 본 시스템은 시스템 장애와 같은 상황에서 시스템이 멈추지 않고 작동할 수 있는 자동복구 기능을 제공한다. 마지막으로, 본 시스템은 NoSQL 기반의 MongoDB를 이용하여 분산 데이터베이스를 구축함으로써 효율적으로 비정형로그데이터를 처리하는 기능을 제공한다. MySQL과 같은 관계형 데이터베이스는 복잡한 스키마 구조를 가지고 있기 때문에 비정형 로그데이터를 처리하기에 적합하지 않은 구조를 가지고 있다. 또한, 관계형 데이터베이스의 엄격한 스키마 구조는 장기간 데이터가 축적되거나, 데이터가 급격하게 증가할 때 저장된 데이터를 분할하여 여러 노드에 분산시키는 노드 확장이 어렵다는 문제점을 가지고 있다. NoSQL은 관계형 데이터베이스에서 제공하는 복잡한 연산을 지원하지는 않지만 데이터가 빠르게 증가할 때 노드 분산을 통한 데이터베이스 확장이 매우 용이하며 비정형 데이터를 처리하는데 매우 적합한 구조를 가지고 있는 비관계형 데이터베이스이다. NoSQL의 데이터 모델은 주로 키-값(Key-Value), 컬럼지향(Column-oriented), 문서지향(Document-Oriented)형태로 구분되며, 제안한 시스템은 스키마 구조가 자유로운 문서지향(Document-Oriented) 데이터 모델의 대표 격인 MongoDB를 도입하였다. 본 시스템에 MongoDB를 도입한 이유는 유연한 스키마 구조에 따른 비정형 로그데이터 처리의 용이성뿐만 아니라, 급격한 데이터 증가에 따른 유연한 노드 확장, 스토리지 확장을 자동적으로 수행하는 오토샤딩 (AutoSharding) 기능을 제공하기 때문이다. 본 논문에서 제안하는 시스템은 크게 로그 수집기 모듈, 로그 그래프생성 모듈, MongoDB 모듈, Hadoop기반 분석 모듈, MySQL 모듈로 구성되어져 있다. 로그 수집기 모듈은 각 은행에서 고객의 업무 프로세스 시작부터 종료 시점까지 발생하는 로그데이터가 클라우드 서버로 전송될 때 로그데이터 종류에 따라 데이터를 수집하고 분류하여 MongoDB 모듈과 MySQL 모듈로 분배하는 기능을 수행한다. 로그 그래프생성 모듈은 수집된 로그데이터를 분석시점, 분석종류에 따라 MongoDB 모듈, Hadoop기반 분석 모듈, MySQL 모듈에 의해서 분석되어진 결과를 사용자에게 웹 인터페이스 형태로 제공하는 역할을 한다. 실시간적 로그데이터분석이 필요한 로그데이터는 MySQL 모듈로 저장이 되어 로그 그래프생성 모듈을 통하여 실시간 로그데이터 정보를 제공한다. 실시간 분석이 아닌 단위시간당 누적된 로그데이터의 경우 MongoDB 모듈에 저장이 되고, 다양한 분석사항에 따라 사용자에게 그래프화해서 제공된다. MongoDB 모듈에 누적된 로그데이터는 Hadoop기반 분석모듈을 통해서 병렬 분산 처리 작업이 수행된다. 성능 평가를 위하여 로그데이터 삽입, 쿼리 성능에 대해서 MySQL만을 적용한 로그데이터 처리시스템과 제안한 시스템을 비교 평가하였으며 그 성능의 우수성을 검증하였다. 또한, MongoDB의 청크 크기별 로그데이터 삽입 성능평가를 통해 최적화된 청크 크기를 확인하였다.

• Journal of the Korean Wood Science and Technology
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• 제2권2호
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• pp.32-34
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• 1974

본 논문은 1968년 과학기술처 Trust Fund에 의하여 실시된 연구로서 전남 지방에 있어서 최적합한 양송이 재배사를 구명하기 위하여 이미 구미에서 연구된 결과를 토대로 하여 우리나라의 기후적 조건과 경제적 조건을 고찰한 자연공기 순환법을 적용, 양송이 재배에 최적한 환경 조건과 이의 조절법을 구명코저 시상식재배사와 지하실에 구축한 태양열을 이용하는 태양열식 재배사를 본실험용으로 구축하고 전자에 대하여서는 외가의 온도의 영향을 받지 아니하는 측벽구조와 천정의 구조, 환기구의 위치 및 그 환기량등에 관하여 검토하였으며 후자에 관하여는 태양열 이용 효과에 대하여 검토하였다. 또한 동기에 있어서의 계속적 재배를 가능케 하기 위하여 양송이 재배사의 보온에 적합한 가열 장치에 대하여서도 검토하였다. 1. 실험용 지상식 양송이 재배사의 효과에 관하여는 이미 실험결과 및 그 분석에서 지적된 바 있거니와 그 측벽 및 천정의 구조는 재배사를 외계의 기상조건에서 격리하는데 충부한 효과가 있는 것으로 고려된다. 2. 반지하실에 구축한 실험용 태양식 양송이 재배사의 효과에 관하여는 실험결과 및 그 분석에 지적한 바와 같거니와 태양열을 이용하는데 있어 충분한 효과가 있는 것으로 고려된다. 그러나 이것을 농가에 적용하기 위하여는 다음과 같은 제점이 개선되어야 할 것으로 고려된다. 즉 (1) 태양식의 지붕과 천정은 실험용 지상식재배사의 그것과 동일히 하고, (2) 태양열 수열 장치는 적당히 제고되어야 할 것으로 고려된다. 3. 본 실험 연구에서 실시한 각조의 환기법중 GE-CV 및 VS-CV 환기법이 가장 효과적인 것으로 본다. 4. 측벽수치 및 지중 환기장치는 이미 지적한 바와 같이 농가용 양송이재배사의 자연환기법으로 실용적 가치가 충분하다. 그것은 이들 환기장치는 그 환기로를 통하여 사내에 유입되는 외기의 온도를 인공적으로 가열이나 또는 냉각하지 않고 사내 온도에 접근하지 않도록 조절하는 효과가 있기 때문이다. 지금 외온을 $X^{\circ}C$로 할때 각종 환기로에 의하여 흡수되는 온도 $Y^{\circ}C$를 X의 함수로 하는 실험식은 다음과 같이 회귀직선으로 표시된다. GP$\cdots$Y=0.9X-12.8 GE$\cdots$Y=0.96X-15.11 VS$\cdots$Y=0.94X-17.57 5. 재배사내에 유입되는 공기 및 사외로 배출되는 공기에 관한 실험식은 다음과 같이 회귀직선 및 지수곡선으로 표시된다. 5.1 배출속도 Ycm/sec.를 유입속도 Xcm/sec.의 함수로 하는 회귀직선식 GE-CV(50%)법$\cdots$Y=1.0X-1.65 GE-CV(100%)법$\cdots$Y=0.42X+2.03 VS-CV(100%)법$\cdots$Y=0.85X+0.96 5.2 배출량 $Ym^3$/hr.를 유출량${\times}m^3$/hr.의 함수로 하는 회귀직선식 GE-CV(50%)법$\cdots$Y=2.59X-10.88 GE-CV(100%)법$\cdots$Y=2.16X+26.53 5.3 상면 공기이동 속도 Ym/sec.를 배출공기 속도${\times}m$/sec.의 함수로 하는 회귀직선식 GE-CV(50%)법$\cdots$Y=0.5X+0.84 5.4 $CO_2$ 축적량 Y(%)를 상면공기이동속도 cm/sec.의 함수로 하는 회귀직선식 GE-CV(50%)$\cdots$Y=114.53-6.42X 5.5 $CO_2$ 축적량Y(%)를 배출공기량 $m^3$/hr.의 함수로 하는 지수곡선식 GE-CV(50%)$\cdots$Y=$127.18{\times}1.0093^{-x}$ 5.6 Natural ventilation system에 있어서 양송이 생육에 적합한 환경적조건을 마련하기 위한 환기구의 단면적은 재배사 전용적에 대하여 다음과 같은 비율로할 수 있다. GE(지중유입 환기구 단면적)$\cdots$0.3-0.5%(요조절) CV(천정배출 환기구 단면적)$\cdots$0.8-1.0% (요조절) 6. 본 연구에서 실험한 각종의 가열장치중 무압증기수 보이라도 사요할 수 있는 온수 보이라가 농가용 양송이재배사 가열장치로서, 그 효과면에 있어서나 또는 그 가격면에 있어서 최적합다하는 것이 확인되고 있다.

• 지능정보연구
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• 제19권2호
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• pp.1-20
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• 2013

소셜 네트워크는 사용자들의 공통된 관심사, 경험, 그리고 일상 생활들을 함께 공유하기 위해 소셜 네트워크 상 사람들을 서로 연결시켜주는 거대한 커뮤니케이션 플랫폼이다. 소셜 네트워크상의 사용자들은 포스팅, 댓글, 인스턴스 메시지, 게임, 소셜 이벤트 외에도 다양한 애플리케이션을 통해 다른 사용자들과 소통하고 개인 정보 관리하는데 많은 시간을 소비한다. 소셜 네트워크 상의 풍부한 사용자 정보는 추천시스템이 추천 성능을 향상시키기 위해 필요한 큰 잠재력이 되었다. 대부분의 사용자들은 어떤 상품을 구매하기 전 가까운 관계이거나 같은 성향을 가진 사람들의 의견을 반영하여 의사 결정을 하게 된다. 그러므로 소셜 네트워크에서의 사용자 관계는 추천시스템을 위한 사용자 선호도 예측을 효율적으로 높이는데 중요한 요소라 할 수 있다. 일부 연구자들은 소셜 네트워크에서의 사용자와 다른 사용자들 사이의 상호작용 즉, 소셜 관계(social relationship)와 같은 소셜 데이터가 추천시스템에서 추천의 질에 어떠한 영향을 미치는가를 연구하고 있다. 추천시스템은 아마존, 이베이, Last.fm과 같은 큰 규모의 전자상거래 사이트 또한 채택하여 사용되는 시스템으로, 추천시스템을 위한 방법으로는 협업적 여과 방법과 내용 기반 여과 방법이 있다. 협업적 여과 방법은 사용자들의 선호도 학습에 의해 사용자가 아직 평가하지 않은 아이템 중 선호할 수 있는 아이템을 정확하게 제안하기 위한 추천시스템 방법 중 하나이다. 협업적 여과는 사용자들의 데이터에 초점을 맞춘 방법으로 유사한 배경과 선호도를 가지는 사용자들로부터 정보를 수집하여 사용자들의 선호도 예측을 자동으로 발생시킨다. 특히 협업적 여과는 근접한 이웃 사용자들에 의해서 목적 사용자가 선호할 수 있는 아이템을 제시하는 것으로 유사한 이웃 사용자를 찾는 것이 중요하다. 좋은 이웃 사용자 발견은 사용자와 아이템을 고려하는 방법이 일반적이다. 각 사용자는 아이템 즉, 영화, 상품, 책 등에 자신의 선호도를 나타내기 위하여 평가 값을 입력하고, 시스템은 이를 바탕으로 사용자-평가 행렬을 구축한다. 이 사용자-평가 행렬은 목적 사용자와 유사하게 아이템을 평가한 사용자 그룹을 찾기 위한 것으로, 목적 사용자가 아직 평가하지 않은 아이템에 대하여 사용자-평가 매트릭스를 통해 그 평가 값을 예측한다. 현재 이 협업적 여과 방법은 전자상거래와 정보 검색에서 적용되어 개인화 시스템에 효율적으로 사용되고 있다. 하지만 초기 사용자 문제, 데이터 희박성 문제와 확장성 그리고 예측 정확도 향상 등 해결해야 할 과제가 여전히 남아 있다. 이러한 문제들을 해소하기 위해 많은 연구자들은 하이브리드, 신뢰기반, 소셜 네트워크 기반 협업적 여과와 같은 다양한 방법을 제안하였다. 본 논문에서는 전통적인 협업적 여과 방식의 예측 정확도와 추천 성능을 향상시키기 위해 소셜 네트워크에 존재하는 소셜 관계를 이용한 협업적 여과 시스템을 제안한다. 소셜 관계는 소셜 네트워크 서비스 중 하나인 페이스북 사용자들이 남긴 포스팅과 사용자의 소셜 네트워크 친구와 의견 교류 중 남긴 코멘트와 같은 사용자 행동을 기반으로 정의된다. 소셜 관계를 구축하기 위해 소셜 네트워크 사용자의 포스팅과 댓글을 추출하고, 추출된 텍스트에 불용어 및 특수 기호 제거와 스테밍 등 전처리를 수행하였다. 특징 벡터는 TF-IDF를 이용하여 전처리된 텍스트에 나타난 각 단어에 대한 특징 점수를 계산함으로써 구축된다. 본 논문에서 이웃 사용자를 결정하기 위해 사용되는 사용자 간 유사도는 특징 벡터를 이용한 사용자 행동 유사도와 사용자의 영화 평가를 기반으로 한 전통적 방법의 유사도를 결합하여 계산된다. 제안하는 시스템은 목표 사용자와 제안한 방법을 통해 결정된 이웃 사용자 집단을 기반으로 목표 사용자가 평가하지 않은 아이템에 대한 선호도를 예측하고 Top-N 아이템을 선별하여 사용자에게 아이템을 추천하게 된다. 본 논문에서 제안하는 방법을 확인하고 평가하기 위하여 IMDB에서 제공하는 영화 정보 기반으로 영화 평가 시스템을 구축하였다. 예측 정확도를 평가하기 위해 MAE 값을 이용하여 제안하는 알고리즘이 얼마나 정확한 추천을 수행하는지에 대한 예측 정확도를 측정하였다. 그리고 정확도, 재현율 및 F1값 등을 활용하여 시스템의 성능을 평가하였으며, 시스템의 추천 품질은 커버리지를 이용하여 평가되었다. 실험 결과로부터 본 논문에서 제안한 시스템이 보다 더 정확하고 좋은 성능으로 사용자에게 아이템을 추천하는 것을 볼 수 있었다. 특히 소셜 네트워크에서 사용자 행동을 기반으로 한 소셜 관계를 이용함으로써 추천 정확도를 6% 향상시킴을 보였다. 또한 벤치마크 알고리즘과의 성능비교 실험을 통해 7% 향상된 추천 성능의 결과를 보여준다. 그러므로 사용자의 행동으로부터 관찰된 소셜 관계를 CF방법과 결합한 제안한 방법이 정확한 추천시스템을 위해 유용하며, 추천시스템의 성능과 품질을 향상시킬 수 있음을 알 수 있다.

• 대한의용생체공학회:의공학회지
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• 제6권2호
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• pp.1-8
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• 1985

The wall shear stress in the vicinity of end-to end anastomoses under steady flow conditions was measured using a flush-mounted hot-film anemometer(FMHFA) probe. The experimental measurements were in good agreement with numerical results except in flow with low Reynolds numbers. The wall shear stress increased proximal to the anastomosis in flow from the Penrose tubing (simulating an artery) to the PTFE: graft. In flow from the PTFE graft to the Penrose tubing, low wall shear stress was observed distal to the anastomosis. Abnormal distributions of wall shear stress in the vicinity of the anastomosis, resulting from the compliance mismatch between the graft and the host artery, might be an important factor of ANFH formation and the graft failure. The present study suggests a correlation between regions of the low wall shear stress and the development of anastomotic neointimal fibrous hyperplasia(ANPH) in end-to-end anastomoses. 30523 T00401030523 ^x Air pressure decay(APD) rate and ultrafiltration rate(UFR) tests were performed on new and saline rinsed dialyzers as well as those roused in patients several times. C-DAK 4000 (Cordis Dow) and CF IS-11 (Baxter Travenol) reused dialyzers obtained from the dialysis clinic were used in the present study. The new dialyzers exhibited a relatively flat APD, whereas saline rinsed and reused dialyzers showed considerable amount of decay. C-DAH dialyzers had a larger APD(11.70$\pm$1.32mmHg/min)compared to CF dialyzers(4.32$\pm$0.55mmHg/min)(p<0.05). However, there was no observable difference in the UFR between the two dialyzers. Neither APD nor UFR showed any significant increase with an increasing number of reuses for up to more than 20reuses. A substantial number of failures observed in APD(larger than 20mmHe/min)on the reused dialyzers(2 out of 40 CP and S out 26 C-DAK) were attributed to the Possible damage on the fibers. The CF 15-11 HFDs which failed APD test did not show changes in the UFR compared to normal dialyzers indicating that APD is a more sensitive test than UFR test to evaluate the integrity of the fibers. 30527 T00401030527 ^x For quantitative measurement of reflected light from a clinical diagnostic strip, a prototype old reflectance photometer was designed. The strip loader and cassette were made to obtain more accurate reflectance parameters. The strip was illuminated at 45˚c through optical fiber and the intensity of reflected light was determined at rectanguLat angle using a photodiode. The kubelka-munk coefficient and reflection optical density were determined ar four different wavelengths(500, 550, 570 and 610nm) for blood glucose strip. For higher concentration than 300mg/41 about glucose, a saturation state of abforbance was observed at 500, 550 and 570nm. The correlation between glucose concentration and parameters was the best at 610nm. 30535 T00401030535 ^x Radiation-induced fibrosarcoma tumors were grown on the flanks of C3H mice. The mice were divided into two groups. One group was injected with Photofrin II, intravenously (2.5mg/kg body weight). The other group received no Photofrin II. Mice from both groups were irradialed for approximately 15 minutes at 100, 300, or 500 mW/cm2 with the argon (488nm/514.5 nm), dye(628nm) and gold vapor (pulsed 628 nm) laser light. A photosensitizer behaved as an added absorber. Under our experimental conditions, the presence of Photolfrin II increased surface temperature by at least 40% and the temperature rise due to 300 mW/cm2 irradiation exceeded values for hyperthermia. Light and temperature distributions with depth were estimated by a computer model. The model demonstrated the influence of wavelength on the thermal process and proved to be a valuable tool to investigate internal temperature rise. 30536 T00401030536 ^x We investigated the structural geometry of thirty-eight Korean femurs. The purpose of this study is to identify major geometrical differences between Korean femurs 3nd others that we believe belong to Caucasians so that we would be able to get insights into the femoral component design that fits Asians including Koreans. We utilized computerized tomography (CT) images of femurs extracted from cadavers. The CT images were transformed into bitmap data by using a film scanner, and then analyzed by using a commercially available software called Image v.1.0 and a Macintosh IIci computer.The resulting data were compared with already published data. The major results show that the geometry of the Korean femurs is significantly different from that of Caucasians: (1) the anteversion angle and the canal flare index are greater by the amount of approximately 8˚ and 0.5, respectively, (2) the shape of the isthmus cross section is more round, and (3) the distance between the teaser trochanter and the proximal border of the isthmus is shelter by about 15 mm. The results suggested that the femoral component suitable for Asians should be different from the currently-used components designed and manufactured mostly by European or American companies. 30537 T00401030537 ^x It is well known that nonlinear propagation characteristics of the wave in the tissue may give very useful information for the medical diagnoisis. In this paper, a new method to detect nonlinear propagation characteristics of the internal vibration in the tissue for the low frequency mechanical vibration by using bispectral analysis is proposed. In the method, low frequency vibration of f0( = 100Hz) is applied on the surface of the object, and the waveform of the internal vibration x (t) is measured from Doppler frequency modulation of silmultaneously transmitted probing ultrasonic waves. Then, the bispectra of the signal x (t) at the frequencies (f0, f0) and (f0, 2f0) are calculated to estimate the nonlinear propagation characteristics as their magnitude ratio, w here since bispectrum is free from the gaussian additive noise we can get the value with high S/N. Basic experimental system is constructed by using 3.0 MHz probing ultrasonic waves and the several experiments are carried out for some phantoms. Results show the superiority of the proposed method to the conventional method using power spectrum and also its usefulness for the tissue characterization. 30541 T00401030541 ^x This paper describes the implementation of a computerized radial pulse diagnosis by aids of a clinical expert. On this base, we composed of the radial pulse diagnosis system in korean traditional medicine. The system composed of a radial pulse wave detection system and a radial pulse diagnosis system. With a detection system, we detected Inyoung and Cheongu radial pulse wave and processed it. Then, we have got the characteristic parameters of radial pulse wave and also quantified that according to the method of Inyoung-Cheongu Comparison Radial Pulse Diagnosis. We defined the jugement standard of radial pulse diagnosis system and then we confirmed the possibility for realization of automatic radial pulse diagnosis in korean traditional medicine. 30545 T00401030545 ^x Microspheres are expected to be applied to biomedical areas such as solid-phase immunoassays, drug delivery systems, immunomagnetic cell separation. To synthesize microspheres for biomedical application, "two stage shot growth method" was developed. The uniformity ratio of synthesized microspheres was always smaller than 1.05. And the surface charge density (or the number of ionizable functional groups) of the microspheres synthesized by "two stage shot growth method" was 6~13 times higher than that of the microspheres synthesized by conventional seeded batch copolymerization. As a previous step for biomedical application, adsorption experiments of bovine albumin on microspheres were carried out under various conditions. The maximum adsorbed amount was obtained in the neighborhood of pH 4.5. Isoelectric point of bovine albumin is pH 5.0, so experimental result shows that it shifted to acid area. The adsorption isotherm was obtained, the plateau region was always reached at 2.Og/L (bulk concentration of bovine albumin).The effect of the kind and the amount of surface functional group was also examined. 30575 T00401030575 ^x A medical image workstation was developed using multimedia technique. The system based on PC-486DX was designed to acquire medical images produced by medical imaging instruments and related audio information, that is, doctors' reporting results. Input information was processed and analyzed, then the results were presented in the form of graph and animation. All the informations of the system were hierarchically related with the image as the apex. Processing and analysis algorithms were implemented so that the diagnostic accuracy could be improved. The diagnosed information can be transferred for patient diagnosis through LAN(local area network). 30592 T00401030592 ^x In the conventional infrared imaging system, complex infrared lens systems are usually used for directing collimated narrow infrared beams into the high speed 2-dimensional optic scanner. In this paper, a simple reflective infrared optic system with a 2-dimensional optic scanner is proposed for the realization of medical infrared thermography system. It has been experimentally proven that the intfrared thermography system composed of the proposed optic system has the temperature resolution of 0.1˚c under the spatial resolution of lmrad, the image matrix size of 256 X 240, and tile imaging time of 4 seconds. 30593 T00401030593 ^x In this paper, MIIS (Medical Image Information System) has been designed and implemented using INGRES RDBMS, which is based on a client/server architecture. The implemented system allows users to register and retrieve patient information, medical images and diagnostic reports. It also provides the function to display these information on workstation windows simultaneously by using the designed menu-driven graphic user interface. The medical image compression/decompression techniques are implemented and integrated into the medical image database system for the efficient data storage and the fast access through the network. 30594 T00401030594 ^x In this paper, computerized BEAM was implemented for the space domain analysis of EEG. Trans-formation from temporal summation to two-dimensional mappings is formed by 4 nearest point inter-polaton method. Methods of representation of BEAM are two. One is dot density method which classify brain electrical potential 9 levels by dot density of gray levels and the other is colour method which classify brain electrical 12 levels by red-green colours. In this BEAM, instantaneous change and average energy distribution over any arbitrary time interval of brain electrical activity could be observed and analyzed easily. In the frequency domain, the distribution of energy spectrum of a special band can easily be distinguished normality and abnormality. 30608 T00401030608 ^x Laboratory information system (LIS) is a key tool to manage laboratory data in clinical pathology. Our department has developed an information system for routine hematology using down-sized computer system. We have used an IBM 486 compatible PC with 16MB main memory, 210 MB hard disk drive, 9 RS-232C port and 24 pin dot printer. The operating system and database management system were SCO UNIX and SCO foxbase, respectively. For program development, we used Xbase language provided by SCO foxbase. The C language was used for interface purpose. To make the system use friendly, pull-down menu was used. The system connected to our hospital information system via application program interface (API), so the information related to patient and request details is automatically transmitted to our computer. Our system interfaced with fwd complete blood count analyzers(Sysmex NE-8000 and Coulter STKS) for unidirectional data tansmission from analyzer to computer. The authors suggests that this system based on down-sized computer could provide a progressive approach to total LIS based on local area network, and the implemented system could serve as a model for other hospital's LIS for routine hematology. 30609 T00401030609 ^x To develop an artificial bone substitute that is gradually degraded and replaced by the regenerated natural bone, the authors designed a composite that is consisted of calcium phosphate and collagen. To use as the structural matrix of the composite, collagen was purified from human umbilical cord. The obtained collagen was treated by pepsin to remove telopeptides, and finally, the immune-free atelocollagen was produced: The cross linked atelocollagen was highly resistant to the collagenase induced collagenolysis. The cross linked collagen demonstrated an improved tensile strength. 30618 T00401030618 ^x This paper is a study on the design of adptive filter for QRS complex detection. We propose a simple adaptive algorithm to increase capability of noise cancelation in QRS complex detection with two stage adaptive filter. At the first stage, background noise is removed and at the next stage, only spectrum of QRS complex components is passed. Two adaptive filters can afford to keep track of the changes of both noise and QRS complex. Each adaptive filter consists of prediction error filter and FIR filter The impulse response of FIR filter uses coefficients of prediction error filter. The detection rates for 105 and 108 of MIT/BIH data base were 99.3% and 97.4% respectively. 30619 T00401030619 ^x To develop an artificial bone substitute that is gradually degraded and replaced by the regenerated natural bone, the authors designed and produced a composite that is consisted of calcium phosphate and collagen. Human umbilical cord origin pepsin treated type I atelocollagen was used as the structural matrix, by which sintered or non-sintered carbonate apatite was encapsulated to form an inorganic-organic composite. With cross linking atelocollagen by UV ray irradiation, the resistance to both compressive and tensile strength was increased. Collagen degradation by the collagenase induced collagenolysis was also decreased. 30620 T00401030620 ^x We have developed a monoleaflet polymer valve as an inexpensive and viable alternative, especially for short-term use in the ventricular assist device or total artificial heart. The frame and leaflet of the polymer valve were made from polyurethane, To evaluate the hemodynamic performance of the polymer valve a comparative study of flow dynamics past a polymer valve and a St. Jude Medical prosthetic valve under physiological pulsatile flow conditions in vitro was made. Comparisons between the valves were made on the transvalvular pressure drop, regurgitation volume and maximum valve opening area. The polymer valve showed smaller regurgitation volume and transvalvular pressure drop compared to the mechanical valve at higher heart rate. The results showed that the functional characteristics of the polymer valve compared favorably with those of the mechanical valve at higher heart rate. 30621 T00401030621 ^x Explosive evaporative removal process of biological tissue by absorption of a CW laser has been simulated by using gelatin and a multimode Nd:YAG laser. Because the point of maximun temperature of laser-irradiated gelatin exists below the surface due to surface cooling, evaporation at the boiling temperature is made explosively from below the surface. The important parameters of this process are the conduction loss to laser power absorption (defined as the conduction-to-laser power parameter, Nk), the convection heat transfer at the surface to conduction loss (defined as Bi), dimensionless extinction coefficient (defined as Br.), and dimensionless irradiation time (defined as Fo). Dependence of Fo on Nk and Bi has been observed by experiment, and the results have been compared with the numerical results obtained by solving a 2-dimensional conduction equation. Fo and explosion depth (from the surface to the point of maximun temperature) are increased when Nk and Bi are increased.To find out the minimum laser power for explosive evaporative removal process, steady state analysis has been also made. The limit of Nk to induce evaporative removal, which is proportional to the inverse of the laser power, has been obtained. 30622 T00401030622 ^x N1 and N2 gross neural action potentials were measured from the round window of the guinea pig cochlea at the onset of the acoustic stimuli. N1-N2 audiograms were made by means of regulating stimulant intensities in order to produce constant N1-N2 potentials as criteria for different input tone pip frequencies. The lowest threshold was measured with an input tone pip I5 dB SPL in intensity and 12 KHz in frequency when the animal was in normal physiological condition. The procedure of experimental measurements is explained in detail. This experimental approach is very useful for the investigation of the Cochlear function. Both noN1inear and active functions of the Cochlea can be monitored by N1-N2 audiograms. 30623 T00401030623 ^x In electrical impedance tomography(EIT), we use boundary current and voltage measurements toprovide the information about the cross-sectional distribution of electrical impedance or resistivity. One of the major problems in EIT has been the inaccessibility of internal voltage or current data in finding the internal impedance values. We propose a new image reconstruction method using internal current density data measured by NMR. We obtained a two-dimensional current density distribution within a phantom by processing the real and imaginary MR images from a 4.77 NMR machine. We implemented a resistivity mage reconstruction algorithm using the finite element method and sensitivity matrix. We presented computer simulation results of the mage reconstruction algorithm and furture direction of the research. 30624 T00401030624 ^x A new method of digital image analysis technique for discrimination of cancer cell was presented in this paper. The object image was the Thyroid eland cells image that was diagnosed as normal and abnormal (two types of abnormal: follicular neoplastic cell, and papillary neoplastic cell), respectively. By using the proposed region segmentation algorithm, the cells were segmented into nucleus. The 16 feature parameters were used to calculate the features of each nucleus. A9 a consequence of using dominant feature parameters method proposed in this paper, discrimination rate of 91.11% was obtained for Thyroid Gland cells. 30625 T00401030625 ^x An electrical stimulator was designed to induce locomotion for paraplegic patients caused by central nervous system injury. Optimal stimulus parameters, which can minimize muscle fatigue and can achieve effective muscle contraction were determined in slow and fast muscles in Sprague-Dawley rats. Stimulus patterns of our stimulator were designed to simulate electromyographic activity monitored during locomotion of normal subjects. Muscle types of the lower extremity were classified according to their mechanical property of contraction, which are slow muscle (msoleus m.) and fast muscle (medial gastrocneminus m., rectus femoris m., vastus lateralis m.). Optimal parameters of electrical stimulation for slow muscles were 20 Hz, 0.2 ms square pulse. For fast muscle, 40 Hz, 0.3 ms square pulse was optimal to produce repeated contraction. Higher stimulus intensity was required when synergistic muscles were stimulated simultaneously than when they were stimulated individually. Electrical stimulation for each muscle was designed to generate bipedal locomotion, so that individual muscles alternate contraction and relaxation to simulate stance and swing phases. Portable electrical stimulator with 16 channels built in microprocessor was constructed and applied to paraplegic patients due to lumbar cord injury. The electrical stimulator restored partially gait function in paraplegic patients. 30626 T00401030626 ^x Two-Dimensional modelling of the Cochlear biomechanics is presented in this paper. The Laplace partial differential equation which represents the fluid mechanics of the Cochlea has been transformed into two-dimensional electrical transmission line. The procedure of this transformation is explained in detail. The comparison between one and two dimensional models is also presented. This electrical modelling of the basilar membrane (BM) is clearly useful for the next approach to the further. Development of active elements which are essential in the producing of the sharp tuning of the BM. This paper shows that two-dimension model is qualitatively better than one-dimensional model both in amplitude and phase responses of the BM displacement. The present model is only for frequency response. However because the model is electrical, the two-dimensional transmission line model can be extended to time response without any difficult. 30627 T00401030627 ^x A method has been proposed for the fully automatic detection of left ventricular endocardial boundary in 2D short axis echocardiogram using geometric model. The procedure has the following three distinct stages. First, the initial center is estimated by the initial center estimation algorithm which is applied to decimated image. Second, the center estimation algorithm is applied to original image and then best-fit elliptic model estimation is processed. Third, best-fit boundary is detected by the cost function which is based on the best-fit elliptic model. The proposed method shows effective result without manual intervention by a human operator. 30628 T00401030628 ^x The intelligent trajectory control method that controls moving direction and average velocity for a prosthetic arm is proposed by pattern recognition and force estimations using EMG signals. Also, we propose the real time trajectory planning method which generates continuous accelleration paths using 3 stage linear filters to minimize the impact to human body induced by arm motions and to reduce the muscle fatigue. We use combination of MLP and fuzzy filter for pattern recognition to estimate the direction of a muscle and Hogan's method for the force estimation. EMG signals are acquired by using a amputation simulator and 2 dimensional joystick motion. The simulation results of proposed prosthetic arm control system using the EMf signals show that the arm is effectively followed the desired trajectory depended on estimated force and direction of muscle movements. 30638 T00401030638 ^x A new neural network architecture for the recognition of patterns from images is proposed, which is partially based on the results of physiological studies. The proposed network is composed of multi-layers and the nerve cells in each layer are connected by spatial filters which approximate receptive fields in optic nerve fields. In the proposed method, patterns recognition for complicated images is carried out using global features as well as local features such as lines and end-points. A new generating method of matched filers representing global features is proposed in this network. 30659 T00401030659 ^x An implementation scheme of the magnetic nerve stimulator using a switching mode power supply is proposed. By using a switching mode power supply rather than a conventional linear power supply for charging high voltage capacitors, the weight and size of the magnetic nerve stimulator can be considerably reduced. Maximum output voltage of the developed magnetic nerve stimulator using the switching mode power supply is 3, 000 volts and switching time is about 100 msec. Experimental results or human nerve stimulations using the developed stimulator are presented. 30768 T00401030768 ^x In this paper, we describe the design methodology and specifications of the developed module-based bedside monitors for patient monitoring. The bedside monitor consists of a main unit and module cases with various parameter modules. The main unit includes a 12.1" TFT color LCD, a main CPU board, and peripherals such as a module controller, Ethernet LAN card, video card, rotate/push button controller, etc. The main unit can connect at maximum three module cases each of which can accommodate up to 7 parameter modules. They include the modules for electrocardiograph, respiration, invasive blood pressure, noninvasive blood pressure, temperature, and SpO2 with Plethysmograph.SpO2 with Plethysmograph.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
• /
• 한국우주과학회 1993년도 한국우주과학회보 제2권2호
• /
• pp.17-17
• /
• 1993

The wall shear stress in the vicinity of end-to end anastomoses under steady flow conditions was measured using a flush-mounted hot-film anemometer(FMHFA) probe. The experimental measurements were in good agreement with numerical results except in flow with low Reynolds numbers. The wall shear stress increased proximal to the anastomosis in flow from the Penrose tubing (simulating an artery) to the PTFE: graft. In flow from the PTFE graft to the Penrose tubing, low wall shear stress was observed distal to the anastomosis. Abnormal distributions of wall shear stress in the vicinity of the anastomosis, resulting from the compliance mismatch between the graft and the host artery, might be an important factor of ANFH formation and the graft failure. The present study suggests a correlation between regions of the low wall shear stress and the development of anastomotic neointimal fibrous hyperplasia(ANPH) in end-to-end anastomoses. 30523 T00401030523 ^x Air pressure decay(APD) rate and ultrafiltration rate(UFR) tests were performed on new and saline rinsed dialyzers as well as those roused in patients several times. C-DAK 4000 (Cordis Dow) and CF IS-11 (Baxter Travenol) reused dialyzers obtained from the dialysis clinic were used in the present study. The new dialyzers exhibited a relatively flat APD, whereas saline rinsed and reused dialyzers showed considerable amount of decay. C-DAH dialyzers had a larger APD(11.70${\pm}$1.32mmHg/min)compared to CF dialyzers(4.32${\pm}$0.55mmHg/min)(p<0.05). However, there was no observable difference in the UFR between the two dialyzers. Neither APD nor UFR showed any significant increase with an increasing number of reuses for up to more than 20reuses. A substantial number of failures observed in APD(larger than 20mmHe/min)on the reused dialyzers(2 out of 40 CP and S out 26 C-DAK) were attributed to the Possible damage on the fibers. The CF 15-11 HFDs which failed APD test did not show changes in the UFR compared to normal dialyzers indicating that APD is a more sensitive test than UFR test to evaluate the integrity of the fibers. 30527 T00401030527 ^x For quantitative measurement of reflected light from a clinical diagnostic strip, a prototype old reflectance photometer was designed. The strip loader and cassette were made to obtain more accurate reflectance parameters. The strip was illuminated at 45˚c through optical fiber and the intensity of reflected light was determined at rectanguLat angle using a photodiode. The kubelka-munk coefficient and reflection optical density were determined ar four different wavelengths(500,550,570 and 610nm) for blood glucose strip. For higher concentration than 300mg/41 about glucose, a saturation state of abforbance was observed at 500,550 and 570nm. The correlation between glucose concentration and parameters was the best at 610nm. 30535 T00401030535 ^x Radiation-induced fibrosarcoma tumors were grown on the flanks of C3H mice. The mice were divided into two groups. One group was injected with Photofrin II, intravenously (2.5mg/kg body weight). The other group received no Photofrin II. Mice from both groups were irradialed for approximately 15 minutes at 100,300, or 500 mW/cm2 with the argon (488nm/514.5 nm), dye(628nm) and gold vapor (pulsed 628 nm) laser light. A photosensitizer behaved as an added absorber. Under our experimental conditions, the presence of Photolfrin II increased surface temperature by at least 40% and the temperature rise due to 300 mW/cm2 irradiation exceeded values for hyperthermia. Light and temperature distributions with depth were estimated by a computer model. The model demonstrated the influence of wavelength on the thermal process and proved to be a valuable tool to investigate internal temperature rise. 30536 T00401030536 ^x We investigated the structural geometry of thirty-eight Korean femurs. The purpose of this study is to identify major geometrical differences between Korean femurs 3nd others that we believe belong to Caucasians so that we would be able to get insights into the femoral component design that fits Asians including Koreans. We utilized computerized tomography (CT) images of femurs extracted from cadavers. The CT images were transformed into bitmap data by using a film scanner, and then analyzed by using a commercially available software called Image v.1.0 and a Macintosh IIci computer.The resulting data were compared with already published data. The major results show that the geometry of the Korean femurs is significantly different from that of Caucasians: (1) the anteversion angle and the canal flare index are greater by the amount of approximately 8˚ and 0.5, respectively, (2) the shape of the isthmus cross section is more round, and (3) the distance between the teaser trochanter and the proximal border of the isthmus is shelter by about 15 mm. The results suggested that the femoral component suitable for Asians should be different from the currently-used components designed and manufactured mostly by European or American companies. 30537 T00401030537 ^x It is well known that nonlinear propagation characteristics of the wave in the tissue may give very useful information for the medical diagnoisis. In this paper, a new method to detect nonlinear propagation characteristics of the internal vibration in the tissue for the low frequency mechanical vibration by using bispectral analysis is proposed. In the method, low frequency vibration of f0( = 100Hz) is applied on the surface of the object, and the waveform of the internal vibration x (t) is measured from Doppler frequency modulation of silmultaneously transmitted probing ultrasonic waves. Then, the bispectra of the signal x (t) at the frequencies (f0, f0) and (f0, 2f0) are calculated to estimate the nonlinear propagation characteristics as their magnitude ratio, w here since bispectrum is free from the gaussian additive noise we can get the value with high S/N. Basic experimental system is constructed by using 3.0 MHz probing ultrasonic waves and the several experiments are carried out for some phantoms. Results show the superiority of the proposed method to the conventional method using power spectrum and also its usefulness for the tissue characterization. 30541 T00401030541 ^x This paper describes the implementation of a computerized radial pulse diagnosis by aids of a clinical expert. On this base, we composed of the radial pulse diagnosis system in korean traditional medicine. The system composed of a radial pulse wave detection system and a radial pulse diagnosis system. With a detection system, we detected Inyoung and Cheongu radial pulse wave and processed it. Then, we have got the characteristic parameters of radial pulse wave and also quantified that according to the method of Inyoung-Cheongu Comparison Radial Pulse Diagnosis. We defined the jugement standard of radial pulse diagnosis system and then we confirmed the possibility for realization of automatic radial pulse diagnosis in korean traditional medicine. 30545 T00401030545 ^x Microspheres are expected to be applied to biomedical areas such as solid-phase immunoassays, drug delivery systems, immunomagnetic cell separation. To synthesize microspheres for biomedical application, "two stage shot growth method" was developed. The uniformity ratio of synthesized microspheres was always smaller than 1.05. And the surface charge density (or the number of ionizable functional groups) of the microspheres synthesized by "two stage shot growth method" was 6~13 times higher than that of the microspheres synthesized by conventional seeded batch copolymerization. As a previous step for biomedical application, adsorption experiments of bovine albumin on microspheres were carried out under various conditions. The maximum adsorbed amount was obtained in the neighborhood of pH 4.5. Isoelectric point of bovine albumin is pH 5.0, so experimental result shows that it shifted to acid area. The adsorption isotherm was obtained, the plateau region was always reached at 2.Og/L (bulk concentration of bovine albumin).The effect of the kind and the amount of surface functional group was also examined. 30575 T00401030575 ^x A medical image workstation was developed using multimedia technique. The system based on PC-486DX was designed to acquire medical images produced by medical imaging instruments and related audio information, that is, doctors' reporting results. Input information was processed and analyzed, then the results were presented in the form of graph and animation. All the informations of the system were hierarchically related with the image as the apex. Processing and analysis algorithms were implemented so that the diagnostic accuracy could be improved. The diagnosed information can be transferred for patient diagnosis through LAN(local area network). 30592 T00401030592 ^x In the conventional infrared imaging system, complex infrared lens systems are usually used for directing collimated narrow infrared beams into the high speed 2-dimensional optic scanner. In this paper, a simple reflective infrared optic system with a 2-dimensional optic scanner is proposed for the realization of medical infrared thermography system. It has been experimentally proven that the intfrared thermography system composed of the proposed optic system has the temperature resolution of 0.1˚c under the spatial resolution of lmrad, the image matrix size of 256 X 240, and tile imaging time of 4 seconds. 30593 T00401030593 ^x In this paper, MIIS (Medical Image Information System) has been designed and implemented using INGRES RDBMS, which is based on a client/server architecture. The implemented system allows users to register and retrieve patient information, medical images and diagnostic reports. It also provides the function to display these information on workstation windows simultaneously by using the designed menu-driven graphic user interface. The medical image compression/decompression techniques are implemented and integrated into the medical image database system for the efficient data storage and the fast access through the network. 30594 T00401030594 ^x In this paper, computerized BEAM was implemented for the space domain analysis of EEG. Trans-formation from temporal summation to two-dimensional mappings is formed by 4 nearest point inter-polaton method. Methods of representation of BEAM are two. One is dot density method which classify brain electrical potential 9 levels by dot density of gray levels and the other is colour method which classify brain electrical 12 levels by red-green colours. In this BEAM, instantaneous change and average energy distribution over any arbitrary time interval of brain electrical activity could be observed and analyzed easily. In the frequency domain, the distribution of energy spectrum of a special band can easily be distinguished normality and abnormality. 30608 T00401030608 ^x Laboratory information system (LIS) is a key tool to manage laboratory data in clinical pathology. Our department has developed an information system for routine hematology using down-sized computer system. We have used an IBM 486 compatible PC with 16MB main memory, 210 MB hard disk drive, 9 RS-232C port and 24 pin dot printer. The operating system and database management system were SCO UNIX and SCO foxbase, respectively. For program development, we used Xbase language provided by SCO foxbase. The C language was used for interface purpose. To make the system use friendly, pull-down menu was used. The system connected to our hospital information system via application program interface (API), so the information related to patient and request details is automatically transmitted to our computer. Our system interfaced with fwd complete blood count analyzers(Sysmex NE-8000 and Coulter STKS) for unidirectional data tansmission from analyzer to computer. The authors suggests that this system based on down-sized computer could provide a progressive approach to total LIS based on local area network, and the implemented system could serve as a model for other hospital's LIS for routine hematology. 30609 T00401030609 ^x To develop an artificial bone substitute that is gradually degraded and replaced by the regenerated natural bone, the authors designed a composite that is consisted of calcium phosphate and collagen. To use as the structural matrix of the composite, collagen was purified from human umbilical cord. The obtained collagen was treated by pepsin to remove telopeptides, and finally, the immune-free atelocollagen was produced: The cross linked atelocollagen was highly resistant to the collagenase induced collagenolysis. The cross linked collagen demonstrated an improved tensile strength. 30618 T00401030618 ^x This paper is a study on the design of adptive filter for QRS complex detection. We propose a simple adaptive algorithm to increase capability of noise cancelation in QRS complex detection with two stage adaptive filter. At the first stage, background noise is removed and at the next stage, only spectrum of QRS complex components is passed. Two adaptive filters can afford to keep track of the changes of both noise and QRS complex. Each adaptive filter consists of prediction error filter and FIR filter The impulse response of FIR filter uses coefficients of prediction error filter. The detection rates for 105 and 108 of MIT/BIH data base were 99.3% and 97.4% respectively. 30619 T00401030619 ^x To develop an artificial bone substitute that is gradually degraded and replaced by the regenerated natural bone, the authors designed and produced a composite that is consisted of calcium phosphate and collagen. Human umbilical cord origin pepsin treated type I atelocollagen was used as the structural matrix, by which sintered or non-sintered carbonate apatite was encapsulated to form an inorganic-organic composite. With cross linking atelocollagen by UV ray irradiation, the resistance to both compressive and tensile strength was increased. Collagen degradation by the collagenase induced collagenolysis was also decreased. 30620 T00401030620 ^x We have developed a monoleaflet polymer valve as an inexpensive and viable alternative, especially for short-term use in the ventricular assist device or total artificial heart. The frame and leaflet of the polymer valve were made from polyurethane, To evaluate the hemodynamic performance of the polymer valve a comparative study of flow dynamics past a polymer valve and a St. Jude Medical prosthetic valve under physiological pulsatile flow conditions in vitro was made. Comparisons between the valves were made on the transvalvular pressure drop, regurgitation volume and maximum valve opening area. The polymer valve showed smaller regurgitation volume and transvalvular pressure drop compared to the mechanical valve at higher heart rate. The results showed that the functional characteristics of the polymer valve compared favorably with those of the mechanical valve at higher heart rate. 30621 T00401030621 ^x Explosive evaporative removal process of biological tissue by absorption of a CW laser has been simulated by using gelatin and a multimode Nd:YAG laser. Because the point of maximun temperature of laser-irradiated gelatin exists below the surface due to surface cooling, evaporation at the boiling temperature is made explosively from below the surface. The important parameters of this process are the conduction loss to laser power absorption (defined as the conduction-to-laser power parameter, Nk), the convection heat transfer at the surface to conduction loss (defined as Bi), dimensionless extinction coefficient (defined as Br.), and dimensionless irradiation time (defined as Fo). Dependence of Fo on Nk and Bi has been observed by experiment, and the results have been compared with the numerical results obtained by solving a 2-dimensional conduction equation. Fo and explosion depth (from the surface to the point of maximun temperature) are increased when Nk and Bi are increased.To find out the minimum laser power for explosive evaporative removal process, steady state analysis has been also made. The limit of Nk to induce evaporative removal, which is proportional to the inverse of the laser power, has been obtained. 30622 T00401030622 ^x N1 and N2 gross neural action potentials were measured from the round window of the guinea pig cochlea at the onset of the acoustic stimuli. N1-N2 audiograms were made by means of regulating stimulant intensities in order to produce constant N1-N2 potentials as criteria for different input tone pip frequencies. The lowest threshold was measured with an input tone pip I5 dB SPL in intensity and 12 KHz in frequency when the animal was in normal physiological condition. The procedure of experimental measurements is explained in detail. This experimental approach is very useful for the investigation of the Cochlear function. Both noN1inear and active functions of the Cochlea can be monitored by N1-N2 audiograms. 30623 T00401030623 ^x In electrical impedance tomography(EIT), we use boundary current and voltage measurements toprovide the information about the cross-sectional distribution of electrical impedance or resistivity. One of the major problems in EIT has been the inaccessibility of internal voltage or current data in finding the internal impedance values. We propose a new image reconstruction method using internal current density data measured by NMR. We obtained a two-dimensional current density distribution within a phantom by processing the real and imaginary MR images from a 4.77 NMR machine. We implemented a resistivity mage reconstruction algorithm using the finite element method and sensitivity matrix. We presented computer simulation results of the mage reconstruction algorithm and furture direction of the research. 30624 T00401030624 ^x A new method of digital image analysis technique for discrimination of cancer cell was presented in this paper. The object image was the Thyroid eland cells image that was diagnosed as normal and abnormal (two types of abnormal: follicular neoplastic cell, and papillary neoplastic cell), respectively. By using the proposed region segmentation algorithm, the cells were segmented into nucleus. The 16 feature parameters were used to calculate the features of each nucleus. A9 a consequence of using dominant feature parameters method proposed in this paper, discrimination rate of 91.11% was obtained for Thyroid Gland cells. 30625 T00401030625 ^x An electrical stimulator was designed to induce locomotion for paraplegic patients caused by central nervous system injury. Optimal stimulus parameters, which can minimize muscle fatigue and can achieve effective muscle contraction were determined in slow and fast muscles in Sprague-Dawley rats. Stimulus patterns of our stimulator were designed to simulate electromyographic activity monitored during locomotion of normal subjects. Muscle types of the lower extremity were classified according to their mechanical property of contraction, which are slow muscle (msoleus m.) and fast muscle (medial gastrocneminus m., rectus femoris m., vastus lateralis m.). Optimal parameters of electrical stimulation for slow muscles were 20 Hz, 0.2 ms square pulse. For fast muscle, 40 Hz, 0.3 ms square pulse was optimal to produce repeated contraction. Higher stimulus intensity was required when synergistic muscles were stimulated simultaneously than when they were stimulated individually. Electrical stimulation for each muscle was designed to generate bipedal locomotion, so that individual muscles alternate contraction and relaxation to simulate stance and swing phases. Portable electrical stimulator with 16 channels built in microprocessor was constructed and applied to paraplegic patients due to lumbar cord injury. The electrical stimulator restored partially gait function in paraplegic patients. 30626 T00401030626 ^x Two-Dimensional modelling of the Cochlear biomechanics is presented in this paper. The Laplace partial differential equation which represents the fluid mechanics of the Cochlea has been transformed into two-dimensional electrical transmission line. The procedure of this transformation is explained in detail. The comparison between one and two dimensional models is also presented. This electrical modelling of the basilar membrane (BM) is clearly useful for the next approach to the further. Development of active elements which are essential in the producing of the sharp tuning of the BM. This paper shows that two-dimension model is qualitatively better than one-dimensional model both in amplitude and phase responses of the BM displacement. The present model is only for frequency response. However because the model is electrical, the two-dimensional transmission line model can be extended to time response without any difficult. 30627 T00401030627 ^x A method has been proposed for the fully automatic detection of left ventricular endocardial boundary in 2D short axis echocardiogram using geometric model. The procedure has the following three distinct stages. First, the initial center is estimated by the initial center estimation algorithm which is applied to decimated image. Second, the center estimation algorithm is applied to original image and then best-fit elliptic model estimation is processed. Third, best-fit boundary is detected by the cost function which is based on the best-fit elliptic model. The proposed method shows effective result without manual intervention by a human operator. 30628 T00401030628 ^x The intelligent trajectory control method that controls moving direction and average velocity for a prosthetic arm is proposed by pattern recognition and force estimations using EMG signals. Also, we propose the real time trajectory planning method which generates continuous accelleration paths using 3 stage linear filters to minimize the impact to human body induced by arm motions and to reduce the muscle fatigue. We use combination of MLP and fuzzy filter for pattern recognition to estimate the direction of a muscle and Hogan's method for the force estimation. EMG signals are acquired by using a amputation simulator and 2 dimensional joystick motion. The simulation results of proposed prosthetic arm control system using the EMf signals show that the arm is effectively followed the desired trajectory depended on estimated force and direction of muscle movements. 30638 T00401030638 ^x A new neural network architecture for the recognition of patterns from images is proposed, which is partially based on the results of physiological studies. The proposed network is composed of multi-layers and the nerve cells in each layer are connected by spatial filters which approximate receptive fields in optic nerve fields. In the proposed method, patterns recognition for complicated images is carried out using global features as well as local features such as lines and end-points. A new generating method of matched filers representing global features is proposed in this network. 30659 T00401030659 ^x An implementation scheme of the magnetic nerve stimulator using a switching mode power supply is proposed. By using a switching mode power supply rather than a conventional linear power supply for charging high voltage capacitors, the weight and size of the magnetic nerve stimulator can be considerably reduced. Maximum output voltage of the developed magnetic nerve stimulator using the switching mode power supply is 3,000 volts and switching time is about 100 msec. Experimental results or human nerve stimulations using the developed stimulator are presented. 30768 T00401030768 ^x In this paper, we describe the design methodology and specifications of the developed module-based bedside monitors for patient monitoring. The bedside monitor consists of a main unit and module cases with various parameter modules. The main unit includes a 12.1" TFT color LCD, a main CPU board, and peripherals such as a module controller, Ethernet LAN card, video card, rotate/push button controller, etc. The main unit can connect at maximum three module cases each of which can accommodate up to 7 parameter modules. They include the modules for electrocardiograph, respiration, invasive blood pressure, noninvasive blood pressure, temperature, and SpO2 with Plethysmograph.