• 제목/요약/키워드: Feature point selection

검색결과 62건 처리시간 0.023초

Ensemble of Nested Dichotomies 기법을 이용한 스마트폰 가속도 센서 데이터 기반의 동작 인지 (Ensemble of Nested Dichotomies for Activity Recognition Using Accelerometer Data on Smartphone)

  • 하으뜸;김정민;류광렬
    • 지능정보연구
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    • 제19권4호
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    • pp.123-132
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    • 2013
  • 최근 스마트 폰에 다양한 센서를 내장할 수 있게 되었고 스마트폰에 내장된 센서를 이용항 동작 인지에 관한 연구가 활발히 진행되고 있다. 스마트폰을 이용한 동작 인지는 노인 복지 지원이나 운동량 측정. 생활 패턴 분석, 운동 패턴 분석 등 다양한 분야에 활용될 수 있다. 하지만 스마트 폰에 내장된 센서를 이용하여 동작 인지를 하는 방법은 사용되는 센서의 수에 따라 단일 센서를 이용한 동작인지와 다중 센서를 이용한 동작인지로 나눌 수 있다. 단일 센서를 이용하는 경우 대부분 가속도 센서를 이용하기 때문에 배터리 부담은 줄지만 다양한 동작을 인지할 때에 특징(feature) 추출의 어려움과 동작 인지 정확도가 낮다는 문제점이 있다. 그리고 다중 센서를 이용하는 경우 대부분 가속도 센서와 중력센서를 사용하고 필요에 따라 다른 센서를 추가하여 동작인지를 수행하며 다양한 동작을 보다 높은 정확도로 인지할 수 있지만 다수의 센서를 사용하기 때문에 배터리 부담이 증가한다는 문제점이 있다. 따라서 본 논문에서는 이러한 문제를 해결하기 위해 스마트 폰에 내장된 가속도 센서를 이용하여 다양한 동작을 높은 정확도로 인지하는 방법을 제안한다. 서로 다른 10가지의 동작을 높을 정확도로 인지하기 위해 원시 데이터로부터 17가지 특징을 추출하고 각 동작을 분류하기 위해 Ensemble of Nested Dichotomies 분류기를 사용하였다. Ensemble of Nested Dichotomies 분류기는 다중 클래스 문제를 다수의 이진 분류 문제로 변형하여 다중 클래스 문제를 해결하는 방법으로 서로 다른 Nested Dichotomy 분류기의 분류 결과를 통해 다중 클래스 문제를 해결하는 기법이다. Nested Dichotomy 분류기 학습에는 Random Forest 분류기를 사용하였다. 성능 평가를 위해 Decision Tree, k-Nearest Neighbors, Support Vector Machine과 비교 실험을 한 결과 Ensemble of Nested Dichotomies 분류기를 사용하여 동작 인지를 수행하는 것이 가장 높은 정확도를 보였다.

초등학교 안전교육 내용분석연구 (A Study on the Contents Analysis of Safety Education in Elementary School : Focusing on Comparison with the Needs of Students)

  • 김탁희;이명선
    • 보건교육건강증진학회지
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    • 제18권2호
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    • pp.45-63
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    • 2001
  • The objective of this study is to give basic materials for selection and improvement of contents of safety education, which is substantially helpful to elementary students, by analysis of contents of safety education in some subjects and assessment of the needs of elementary students for safety education. For this purpose, this study was analyzed the contents of safety education in five subjects for elementary school and conducted the survey of 883 students in some elementary schools in Seoul from April 7 to 22, 2000. The results were as follows; 1. As a result of analysis of the proportion of contents regarding safety-related education in some subjects, Physical Education occupied the highest proportion (14.09%), and that was followed by Practical Subject (9.55%) and Moral Education (9.34%). However, the proportions in Social Study and Natural Science were very low, 1.85% and 1.31% each. In total lines of these five subjects, the numbers of line regarding safety education was contained by 5.78%. 2. Analyzing the proportion of domains of safety education in five textbooks, the Meaning of Safety and Basic Principles occupied the highest portion (29.5%), and that was followed by the Home Safety (24.0%), the Safety in School (17.1%), and the Play and Leisure Safety (14.0%). The Coping with Accidents and First Aid, the Safety from Fire and Explosion, and the Traffic Safety occupied relatively low portion, 6.9%, 5.7%, and 2.8% each. 3. As a result of analysis of the proportion of the safety education domain in each subject, the Meaning of Safety and Basic Principles occupied the highest portion (23.6%) in Moral Education, the Home Safety (12.7%) in Practical Subject, and the Play and Leisure Safety (10.9%) in Physical Education. 4. Most of the participants in this survey experienced the Home Accidents (71.1%). And also, they experienced the Play and Leisure Accidents (57.9%), the Accidents in School (49.7%), the Traffic Accidents (45.3%), and the Fire and Explosion Accidents (24.7%) in order. 5. In the average proportion of the needs of participants for safety education in each domain, the Coping with Accidents and First Aid has the highest point (4.05). And, that was followed by the Home safety (3.79), the Safety from Fire and Explosion (3.73), the Meaning of Safety and Basic Principles (3.65), the Play and Leisure Safety (3.50), the Safety in School (3.37), and the Traffic Safety (3.35). The average proportion of the needs for safety education of total domains was 3.66. 6. In the needs for safety education regarding the feature of participants, it showed higher scores in female students than male ones (p〈0.001), in lower grader than higher grader (p〈0.05), and in the students born to wealth than those born poor (p〈0.05). Also, the children who recognize the necessity of safety education showed higher scores of the needs for safety education (p〈0.001). And it also showed the same results of high score to the children whose parents did the safety education (p〈0.00l) and to the children and their parents who have the higher degree of practicing safety (p〈0.001), and these differences were statistically significant. 7. In the extent of preference for methods of safety education, it showed high score to the Field Learning, followed by the Audio- Visual Education, the Discussion, and the Instruction of teacher. In the extent of preference for subjects regarding the contents of safety education by each domain, it showed high score to the subject of Safety for 4 domains - the Meaning of Safety and Basic Principles, the Traffic Safety, the Safety from Fire and Explosion, and the Coping with Accidents and First Aid. And also, they preferred Moral Education for 2 domains - the Home safety and the Safety in School, and Physical Education for a domain of the Play and Leisure Safety. 8. While 27 of 36 detail items was contained the contents of safety education, the proportion of needs of participants for safety education showed more than average 3.00 score in 34 of 36 detail items. However, none of 9 detail items was included in five textbooks. Also, 2 detail items - the Coping with Disasters and the Safety from Poisoning - were included together 2 parts; One part had the higher ranked 7 items acquired by analysis of the needs, and the other had the higher ranked 7 items acquired by analysis of the contents. But, except those 2 items, none of items were matched with each part.

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